ENVIRONMENTAL IMPACT STATEMENT
ON
MONTREAL PROTOCOL ON SUBSTANCES
THAT DEPLETE THE OZONE LAYER
PREPARED BY
STRATOSPHERIC PROTECTION PROGRAM
OFFICE OF PROGRAM DEVELOPMENT
OFFICE OF AIR AND RADIATION
U.S. ENVIRONMENTAL PROTECTION AGENCY
JANUARY 20, 1988
FINAL ENVIRONMENTAL IMPACT STATEMENT
-------
ENVIRONMENTAL IMPACT STATEMENT
ON
MONTREAL PROTOCOL ON SUBSTANCES
THAT DEPLETE THE OZONE LAYER
PREPARED BY
STRATOSPHERIC PROTECTION PROGRAM
OFFICE OF PROGRAM DEVELOPMENT
OFFICE OF AIR AND RADIATION
U.S. ENVIRONMENTAL PROTECTION AGENCY
JANUARY 20, 1988
FINAL ENVIRONMENTAL IMPACT STATEMENT
-------
EIS ON MONTREAL PROTOCOL ON SUBSTANCES
THAT DEPLETE THE OZONE LAYER
FINAL EIS: This EIS on the Montreal Protocol is being prepared as a
legislative EIS under Council on Environmental Quality guidelines (40 CFR
1506.8). It is being submitted as a final document to the U.S. Senate and is
also being made available to the public for their review. Commenters have 45
days from the date of notice of the availability of this document (to be
published in the Federal Register) to provide EPA with their review. Comments
should be sent to: Stephen Seidel, ANR-445, Office of Program Development;
U.S. Environmental Protection Agency, 401 M Street, S.W. Washington, D.C.
20460.
LEAD AGENCIES: The Environmental Protection Agency and the Department of
State were joint lead agencies in the preparation of this EIS.
CONTACTS: Stephen Seidel, U.S. EPA, (202) 382-2787
Suzanne Butcher, Department of State, (202) 647-9312
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SUMMARY
Since 1974 there has been increasing scientific evidence that the
emissions of chlorofluorocarbons (CFC.<0 and halon compounds could lead to
depletion c£ the ctratosphetic ozone layer. Stratospheric ozone shields the
earth's surface from damaging ultraviolet radiation; depletion of
stratospheric ozone would therefore result in a range of adverse effects on
human health and the environment.
In response to concerns about the destructive effects of ozone depletion,
the United States, along with 23 other nations and the European Economic
Community, recently signed the Montreal Protocol on Substances that Deplete
the Ozone Layer. Among other things, the Protocol calls for a freeze on the
use of CFCs beginning in approximately 1989, a 20 percent reduction in their
use beginning in 1993, and another 30 percent reduction in their use beginning
in 1998. The Protocol also places a freeze on the use of Halons beginning in
approximately 1992.
This Environmental Impact Statement (EIS) evaluates health and
environmental effects in the United States of regulatory actions taken around
the world in accordance with the Protocol. It examines the role of the
stratosphere in protecting human health, welfare, and the environment;
evaluates potential depletion of stratospheric ozone; and describes the
environmental and human health effects of regulatory actions. In addition,
this EIS estimates the social costs of regulatory action taken in the United
States. This EIS examines a range of future control levels, including: (1)
no controls, (2) Protocol controls, (3) controls that are less stringent than
the Protocol, and (4) controls that are more stringent than the Protocol.
For each control level analyzed, this EIS presents estimates of effects
on human health and the environment, including: ozone depletion; cases of skin
cancer; deaths from skin cancer; cataracts cases; changes in sea level; damage
to crop yields; damage to commercial fish harvests; and damage to plastic
materials; and damage to U.S. coastal ports due to sea level rise. The EIS
shows that the restrictions called for in the Montreal Protocol would
substantially reduce health and environmental damages in the United States.
Much of the analysis presented in this EIS is based on two reports
prepared previously by U.S. EPA: Assessing the Risks of Trace Gases that Can
Modify the Stratosphere (1987) (EPA's Risk Assessment); and Regulatory Impact
Analysis: Protection of Stratospheric Ozone (1987) (EPA's Regulatory Impact
Analysis). Selected portions of these documents are included as appendices to
this EIS.
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TABLE OF CONTENTS
Page
Summary i
Chapter 1: Purpose and Need for Action 1-1
Abstract 1-1
Basis of Concern About CFCs and Ozone Depletion 1-1
Past and Current Actions to Protect the Stratosphere .... 1-2
Recent International Negotiations 1-7
Basis for EIS Preparation 1-8
Organization of this EIS 1-10
References - 1-12
Appendix A to Chapter 1: Comments and Responses to
Announcement of EIS 1-13
Chapter 2: Description of Affected Environment 2-1
Abstract 2-1
Evidence of a Changir-; Atmosphere 2-1
Potential Health and Environmental Effects of
Stratospheric Modification 2-24
References 2-31
Chapter 3: Description of Alternatives 3-1
Abstract 3-1
Provisions of the Montreal Protocol 3-2
EIS Alternatives 3-3
Description of Additional Sensitivity Tests - Other
Alternatives Considered 3-4
References 3-12
Chapter 4: Health and Environmental Consequences of Alternatives ... 4-1
Abstract 4-1
Modelling the Effects of Alternatives 4-1
Health and Environmental Consequences of EIS
Alternatives 4-19
Projected Ozone Depletion for Sensitivity Cases 4-33
References 4-45
-------
TABLE OF CONTENTS (continued)
Page
Chapter 5;. Socio-Economic Costs of Alternatives 5-1
Abstract 5-1
Definition of Socio-Economic Costs 5-1
Methods Used to Estimate Social Costs 5-2
Cost Results 5-9
Comparison of Costs and Health and Environmental
Effects 5-11
Health, Safety, and Energy Implications of Chemical
Substitution 5-13
Trade Issues 5-15
References 5-19
Appendix A: Montreal Protocol ori Substances that Deplete the
Ozone Layer
Appendix B: Executive Summary of U.S. EPA, Assessing the Risks of
Trace Gases that can Modify the Stratosphere (1987)
(EPA's Risk Assessment)
Appendix C: Framework and Method for Estimating Costs of
Reducing the Use of Ozone-Depleting Compounds
in the U.S.
Appendix D: Key Sources
Appendix E: List of Preparers and Reviewers
-------
LIST OF EXHIBITS
Page
1-1 CFC-11 and CFC-12 Production in the United States 1-4
2-1 Measured Increases in Tropospheric Concentrations of
CFC-11 (CFC13) 2-2
2-2 ' Measured Increases in Tropospheric Concentrations of
CFC-12 (CF2C12) 2-3
2-3 Measured Increases in Tropospheric Concentrations of
CFC-113 (C2C13F3) 2-4
2-4 Measured Increases in Tropospheric Concentrations of
HCFC-22 (CHC1F2) 2-4
2-5 Measured Increases in Tropospheric Concentrations of
Carbon Tetrachloride (CCl^ 2-6
2-6 Measured Increases in Tropospheric Concentrations
of Methyl Chloroform (O^CC^) 2-7
2-7 Measured Increases in Tropospheric Concentrations
of Halon 1211 (CF2ClBr) 2-8
2-8 Measured Increases in Tropospheric Concentrations
of Nitrous Oxide (N20) 2-9
2-9 Measured Increases in Tropospheric Concentrations
of Carbon Dioxide (C02) 2-10
2-10 Measured Increases in Tropospheric Concentrations
of Methane (CH4) 2-11
2-lla CFC-12: Constant Emissions 2-13
2-llb CFC-12: Atmospheric Concentrations 2-13
2-12a CFC-12: Emissions Reduced 85% 2-14
2-12b CFC-12: Atmospheric Concentrations 2-14
2-13 CFC-12: Atmospheric Concentrations from Different
Emission Trajectories 2-15
2-14 Time Dependent, Globally-Averaged Change in Ozone
for Coupled Perturbations (LLNL 1-D Model) 2-18
2-15 Time Dependent Seasonally-Averaged Change in Ozone
for 3% Growth in CFC Emissions and Coupled Perturbations
(IS 2-D Model) 2-19
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LIST OF EXHIBITS (continued)
2-16 Vertical Distribution of the Ozone Mixing Ratio in
the Upper Stratosphere 2-20
2-17 CIO Vertical Profiles; Models Versus Measurements '.. . 2-21
2-18 Unkehr Decadal Trend 1970-1980 2-23
2-19 Nimbus 7 Antarctic Ozone Measurements; Mean Total Ozone
in October 2-25
2-20 Cumulative Surface Temperature Change 2-30
3-1 Chemical Formula, Atmospheric Lifetime, and Ozone-
Depleting Potential of Potential Ozone-Depleters 3-6
3-2 Signatories to the Montreal Protocol '.... 3-8
3-3 Sensitivity Cases Examined 3-11
4-1 Compound Use in 1985 By Region 4-3
4-2 Projected Use by Compound by Region 4-4
4-3 Growth of Trace Gas Concentrations Over T4me 4-7
4-4 Comparison of Atmospheric Models and Parameterized
Model Used by EPA 4-9
4-5 Percent Change in Weighted UV Energy as a Function
of Change in Ozone Abundance for Three U.S. Regions 4-10
4-6 Dose-Response Coefficients: Non-Melanoma Skin Cancer 4-11
4-7 Dose-Response Coefficients: Melanoma Skin Cancer
Incidence 4-13
4-8 Dose-Response Coefficients: Melanoma Skin Cancer
Mortality 4-14
4-9 Does-Response Coefficients: Cataracts 4-15
4-10 Effect of Increased Levels of Solar UV-B Radiation on
the Predicted Loss of Larval Northern Anchovy from Annual
Populations, Considering the Dose/Dose-Rate Threshold
and Three Vertical Mixing Models 4-16
4-11 Global Ozone Depletion for the No Controls Alternative
and Protocol Alternative 4-21
4-12 Global Ozone Depletion Estimates for EIS Alternatives 3-7... 4-22
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LIST OF EXHIBITS (continued)
4-13 Summary of Global Ozone Depletion Estimates for EIS
Alternatives ; 4-24
4-14 Additional Cases of Nonmelanoma Skin Cancer in the
U.S. for People Bom by 2075 4-25
4-15 Additional Deaths from Nonmelanoma Skin Cancer in the
U.S. for People Born by 2075 4-26
4-16 Melanoma Skin Cancer: Additional Cases and Deaths
in the U.S. for People Born by 2075 4-27
4-17 Additional Cataract Cases in the U.S. for People
Born by 2075 4-28
4-18 Decline in U.S. Commercial Fish Harvests Due to Increased
UV Radiation 4-30
4-19 Decline in Major Grain Crop Harvests in the U.S. Due
to Increased UV Radiation 4-31
4-20 Increase in Tropospheric Ozone (Smog) and Loss in Major
Grain Crop Production in the U.S 4-32
4-21 Costs of Adding UV Stabilizers in Response for Ozone
Depletion 4-34
4-22 Sea Level Rise and Damage to U.S. Coastal Ports 4-35
4-23 Global Ozone Depletion Estimates: Chemical Coverage
Sensitivity Case 4-37
4-24 Global Ozone Depletion Estimates: Stringency
Sensitivity Cases 4-38
4-25 Global Ozone Depletion Estimates: Stringency-Sensitivity
Cases - - Varying USSR Participaton Levels 4-39
4-26 Global Ozone Depletion Estimates: Stringency Sensitivity
Cases -- Varying Developing Nations Participation 4-40
4-27 Global Ozone Depletion Estimates: Global
Participation Sensitivity Cases ' 4-41
4-28 Global Ozone Depletion Estimates: Trace Gas Growth
Sensitivity Cases 4-42
4-29 Global Ozone Depletion Estimates: Rate of Compound
Growth Sensitivity Cases 4-43
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LIST OF EXHIBITS (continued)
4-30 Summary of Global Ozone Depletion Estimates for
EIS Sensitivity Cases 4-44
5-1 Changes in Consumer and Producer Surplus Due to an
Increase in CFC Price 5-6
5-2 Social Cost Estimates for Alternative Levels of CFC
Control 5-10
5-3 Social Cost Estimates for the Protocol Alternative
and Three Sets of Cost Assumptions 5-12
5-4 Summary of Social Costs and Major Benefits in the
U.S. of EIS Alternatives 5-14
5-5 Potential Impacts of the Protocol's Trade Control
Provisions 5-18
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CHAPTER 1
PURPOSE AND NEED FOR ACTION
ABSTRACT
Stratospheric ozone shields the earth's surface from damaging ultraviolet
radiation (UV-B). Since 1974, scientists have theorized that chlorine released
from chlorofluorcarbons (CFCs) in the stratosphere may deplete ozone. Since
the early 1980s, the U.S. has participated in international negotiations under
the auspices of the United Nations Environment Programme (UNEP) aimed at
establishing an international agreement that restricts global use of CFCs.
These negotiations were successfully concluded on September 16, 1987, in
Montreal, Canada when 24 nations, including the United States, signed the
Montreal Protocol on Substances that Deplete the Ozone Layer^-. This
Environmental Impact Statement (EIS) is being prepared in conjunction with
final U.S. agency action with respect to the agreement. It examines the role
of the stratosphere in protecting human health, welfare, and the environment;
evaluates potential depletion of stratospheric ozone; and describes the
environmental and socioeconomic effects of options related to the international
agreement to protect the ozone layer.
This EIS is being prepared by the Department of State and the Environmental
Protection Agency pursuant to section 102(2)(c) of the National Environmental
Policy Act (NEPA) and in furtherance of Executive Order 12114 (E.O. 12114),
"Environmental Effects Abroad of Major Federal Actions" (see sections 2-3(a)
and 2-4(b)(i)). The intent to prepare this EIS was initially announced in the
Federal Register on August 1, 1984 (49 FR 30823) and updated on August 5, 1987
(52 Fjl 29110). Because the Protocol is being sent to the Senate for its advice
and consent, this document is being prepared as a legislative EIS under the
applicable NEPA guidelines (52 F£ 45520, November 30, 1987).
The purpose of this chapter is to summarize past and current actions taken
to protect the stratosphere and the scientific evidence that led to these
actions. The first section addresses the scientific basis for concern about
ozone depletion. The next two sections detail past and current actions taken
internationally to protect the stratosphere, including the recent international
negotiations that led to the signing of the Montreal Protocol. The final two
sections describe the basis for the preparation of this EIS and the
organization of the chapters that follow.
BASIS OF CONCERN ABOUT CFCS AND OZONE DEPLETION
Ozone levels in the atmosphere are the result of complex processes which
affect the rates of creation and destruction of ozone. These processes involve
a dynamic equilibrium, with the sun's ultraviolet radiation breaking apart
ozone (03), and various chemical cycles leading to both its formation and
^ The text of the Montreal Protocol is included as Appendix A to this
document.
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1-2
destruction. ,
In 1974, Molina and Rowland theorized that chlorine atoms from
chlorofluorocarbons (CFCs) could upset this equilibrium and lead to
stratospheric ozone depletion (Molina and Rowland, 1974). CFCs are industrial
compounds that are used as aerosol propellants, foam-blowing agents,
refrigerants, and solvents. One of their major industrial advantages is their
stability, which ensures that they are non-toxic and non-flammable. Molina and
Rowland hypothesized that this stability would allow them to remain intact
until they were eventually transported to the stratosphere, where they would be
dissociated by high-energy solar radiation. This would release chlorine, which
would enter into catalytic reactions that destroy ozone.
Since 1974, considerable, scientific effort has been devoted to studying the
effects of CFCs and other trace gases on stratospheric ozone, and the basic
outline of Molina and Rowland's theory has been further supported. A
comprehensive international assessment, coordinated by the World Meteorological
Organization (WHO, 1986) found that, based on current atmospheric models,
growth in emissions of CFCs would lead to stratospheric ozone depletion.
Production data show that despite restrictions on aerosol uses, world use of
CFCs has been increasing. In fact, based on data collected by the Chemical
Manufacturer's Association, production of CFC-11 and CFC-12 has increased by 17
percent from 1980 to 1986 (CMA, 1987).
The stratospheric ozone layer plays an important role in prc'acting human
health, welfare and the environment. Stratospheric ozone strongly absorbs low-
wavelength ultraviolet radiation (UV-B), thereby decreasing UV-B doses at the
earth's surface. Existing research indicates that increases in UV-B due to
stratospheric ozone depletion could increase the incidence of skin cancer and
cataracts, suppress the human immune system, damage crops and aquatic
organisms, contribute to the formation of smog, and accelerate the degradation
of outdoor materials. These risks were recently evaluated and summarized in
EPA's comprehensive risk assessment, Assessing the Risks of Trace Gases that
can Modify the Stratosphere (EPA, 1987a). The Executive Summary of this
document is included as Appendix B to this EIS.
Protection of the stratosphere is a global issue. CFCs are produced in
approximately 18 countries and are used in many more. Emissions of CFCs are
rapidly mixed throughout the global atmosphere, and their point of origin does
not affect their potential to deplete ozone. To fully safeguard the ozone
layer, global action is essential.
PAST AND CURRENT ACTIONS TO PROTECT THE STRATOSPHERE
Domestic Activities
1. U.S. action to limit CFC's as aerosol propellants
In 1974, in the United States over 50 percent of CFC-11 and CFC-12
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1-3
f\
production (the most widely used CFCs) was used for aerosol propellants .
After Molina and Rowland published their theory linking CFCs to ozone
depletion, this use began to decline. Initial reductions in CFCs used as
aerosol propellants may have been due to economic forces (CFCs were relatively
expensive as propellants) and environmental concern (consumers voluntarily
reduced their use of aerosol sprays). In 1978, Federal regulations were
jointly promulgated by the U.S. Environmental Protection Agency (EPA), acting
under the authority of the Toxic Substances Control Act (43 FR 11318; March 17,
1978); and the Food and Drug Administration, under the Federal Food, Drug, and
Cosmetic Act (43 FR 11301; March 17, 1978), that banned the use of CFCs as non-
essential aerosol propellants. In addition, the Consumer Product Safety
Commission issued regulations requiring all aerosol products containing CFCs to
bear warning labels (42 Fg 42780; August 24, 1977). Significant reductions in
U.S. use of CFCs were achieved (Exhibit 1-1). By 1978, aerosol uses in the
United States in exempted products such as medical devices accounted for only 5
percent of CFC-11 and CFC-12 production (Hammitt et al., 1986).
2. 1977 Clean Air Act Amendments and 1980 ANFR
In the 1977 amendments to the Clean Air Act, the U.S. Congress broadened
EPA's authority to protect the stratosphere. Part B, Section 157, provides
that:
"....the Administrator shall propose regulations for the control of any
substance, practice, process or activity (or any combination thereof) which in
his judgment may reasonably be anticipated to affect the stratosphere,
especially ozone in the stratosphere, if such effect in the stratosphere may
reasonably be anticipated to endanger public health or welfare." —
Acting under this provision, in 1980 the U.S. EPA issued an Advance Notice
of Proposed Rulemaking (ANPR) (45 FR 66726; October 7, 1980), that stated that
EPA was considering regulations to .restrict total CFC production. Because of
the increased scientific and economic complexity of this issue, no regulations
were developed or promulgated under this ANPR.
3. EPA's Stratospheric Ozone Protection Program
In January 1986, the Agency published its Stratospheric Ozone Protection
Plan (51 IS 1257; January 10, 1986). It called for an enhanced program of
research and analysis related to stratospheric ozone protection. In addition,
the plan placed considerable emphasis on U.S. participation in on-going
international research and discussion of global strategies for protecting 'the
ozone layer. Research and analyses prepared as part of this program or
developed by other sources were to serve as the technical basis for EPA to
2 Total U.S. CFC-11 and CFC-12 production in 1974 (154.7 million kilograms
of CFC-11 and 221.1 million kilograms-of CFC-12) is reported in USITC,
Synthetic Organic Chemicals. Annual Series, Washington, DC. Production for
aerosols (86.7 million kilograms of CFC-11 and 123.9 million kilograms of CFC-
12) is based on estimated market shares reported in Wolf (1980), p. 80,
multiplied by total production estimated on p. 73-74.
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1-4
EXHIBIT 1-1
CFC-11 AND CFG-12 PRODUCTION IN THE UNITED STATES
400
360-
320-
280-
240-
Mjllions of 200-
Kilograms
160-
120-
80
40
* A«rosol/Non»«romol division* »r» tslimalt*
1960
1965
1970
1975
1980
198S
Year
Production of CFC-11 and CFC-12 in the United States increased rapidly
throughout the 1960s and early 1970s. Production reached a maximum of 376.4
million kilograms in 1974, with 56 percent used in aerosol sprays. Non-
essential use of CFCs was banned in 1978, and aerosol use today accounts for
only 5 percent of total CFC-11 and CFC-12 production.
Sources: CFC-11 and CFC-12 production data are reported by the United States
International Trade Commission (USITC, 1961-1987). Allocation to aerosol/non-
aerosol use based on Wolf (1980) and Hammitt et al. (1986).
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1-5
decide whether or not to regulate CFCs or other chemicals that may affect the
stratospheric ozone layer. This plan also served as the basis for settling a
lawsuit brought in 1985 by the Natural Resources Defense Council, seeking to
require EPA to act on its 1980 ANPR.
*
The EPA plan called for the Agency to issue a Federal Register notice by
May 1987 summarizing the results of its program and either proposing further
regulation or presenting the basis for a proposed decision to take no further
action. A Federal Register notice promulgating regulations or announcing a
decision to take no immediate action was scheduled for November 1987. In May
1986, this schedule was extended by the District Court. The revised schedule
required EPA to propose by December 1, 1987 a decision on whether further
restrictions were warranted and to promulgate regulations (or a final decision
that none are warranted) by August 1, 1988.
On December 1, 1987, EPA's Administrator signed a notice proposing
regulations to limit CFCs and halons (52 FR 47489, December 14, 1987). The
proposal closely mirrors the terms of the Montreal Protocol. The rule would
regulate the same chemicals on the same phasedown schedule, would include the
same trade provisions, and would only go into effect following United States
ratification of the Protocol and its entry into force. The preamble to the
proposal summarizes the results of an accompanying Regulatory Impact Analysis
(EPA, 1987b) which was also used as the basis for the analysis contained in
this EIS.
International Activities
1. Actions by other countries
Several nations -- Canada, Denmark, Sweden, and Norway --joined the U.S.
in severely restricting CFC use in aerosols. Several other nations took
different approaches to reduce CFC use. The European Economic Community (EEC)
banned increases in production capacity for CFC-11 and CFC-12, required a 30
percent reduction in CFC aerosol use from 1976 levels, and formulated
engineering codes of practice to eliminate unnecessary CFC emissions. Other
nations also implemented restrictions on CFCs including the Netherlands, which
requires a warning label on CFC-propelled aerosols; Portugal, which has banned
CFC production and set CFC import quotas; Australia, which since 1974 has
reduced its use of CFCs in aerosols by two-thirds; Japan, which called for its
industries to reduce their use of CFCs in aerosols and avoid increasing their
CFC-11 and CFC-12 production capacity; and Brazil, which has also implemented a
CFC production capacity cap. While these measures, along with the U.S. limit
on CFCs in aerosols, resulted in dampening use of CFCs, production levels of
the major CFCs (including CFC-113) now exceed those prior to 1974.
2. Initiation of global activities
Recognizing the need for a concerted international response to the threat
of stratospheric ozone depletion, UNEP has sponsored scientific evaluations and
coordinated international negotiations on stratospheric ozone. At its 1981
Montevideo Senior Level Meeting on Environmental Law, the subject was
recommended as a priority for future work within UNEP. On the basis of this
recommendation, the UNEP Governing Council established the Ad Hoc Working Group
of Legal and Technical Experts, which in 1982 began negotiating a global
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1-6
framework convention to protect the stratospheric ozone layer.
During the early rounds of negotiations, discussions aimed at formulating
an international control protocol focused on the extension of policies
previously implemented by individual nations or groups of countries. For
example, the U.S. called for tighter global restrictions on CFC use as aerosol
propellants, and the EEC called for a global cap on CFC production capacity.
At the time, negotiations focused on both a framework convention which
would provide for international cooperation in research and data collection and
a control protocol which would specifically limit use of ozone-depleting
chemicals. Both were scheduled to be completed by April 1985. While no
agreement on a control protocol could be reached within this time period, a
framework treaty, the Vienna Convention for the Protection of the Ozone Layer.
was successfully completed in March 1985.
The Vienna Convention for the Protection of the Ozone Layer was signed by
the U.S. on March 25, 1985; approved by the U.S. Senate on July 24, 1986; and
ratified by the U.S. on August 27, 1986; To date, sixteen states, of the
twenty needed for entry into force, have completed their formal process to
become parties. The Convention consists of 21 Articles and 2 Annexes that
provide for international cooperation in research and exchange of scientific,
technical, and legal information, and that serve as a framework for potential
control protocols.
At the Diplomatic Conference which adopted the Convention in March 1985, a
resolution was passed calling '"or studies and workshops "leading to a more
common understanding of possible scenarios for global production, emissions and
use of CFCs and other substances affecting the ozone layer," to support the
resumption of negotiations on a control protocol in December 1986. Analyses of
the future supply and demand for CFCs and other atmospheric perturbants and
feasibility of emission reduction technologies were presented at an
international workshop in Rome, Italy, in May 1986. Analyses of potential
control strategies to protect the ozone layer were evaluated at an
international workshop in Leesburg, Virginia in September 1986. Domestic
workshops on these same topics were held prior to these UNEP meetings.
The health and environmental effects of stratospheric ozone modification
and global climate change were presented at an international conference co-
sponsored by UNEP and EPA in June 1986 in Arlington, Virginia (UNEP, 1986).
A comprehensive assessment of scientific issues related to ozone monitoring
and modeling and climate change was prepared in 1986 by NASA and others under
the auspices of the WMO (WMO, 1986). In addition, several meetings of UNEP's
Coordinating Committee on the Ozone Layer (CCOL) were held during 1986
involving scientists from around the world. Reports summarizing the current
state of science were issued for background use by nations preparing for the
next round of Protocol negotiations. UNEP also brought together in April 1987
in Wurzberg, FRG, an international panel of atmospheric modelers to compare
their models and to evaluate the effects on potential depletion of control
options being considered as part of a protocol.
Based on this extensive program of research and integration, EPA summarized
the technical understanding of issues related to stratospheric ozone depletion
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1-7
in its recently completed risk assessment, Assessing the Risks of Trace Gases
that can Modify the Stratosphere, which was reviewed and generally endorsed by
EPA's Science Advisory Board in late 1986 and early 1987.
The above-mentioned documents and information developed during the series
of domestic and international workshops were used extensively in the
preparation of the EIS.
RECENT INTERNATIONAL NEGOTIATIONS
By the resumption of negotiations in December 1986, the substance of
proposals differed markedly from the prior round of talks. Despite this change
in thinking, substantial differences existed concerning most key aspects of the
negotiations including the basic approach to controls and their stringency,
timing, and coverage.
At the follow-on negotiating sessions held in February 1987 and April 1987,
substantial differences continued to exist concerning treatment of important
issues essential to any agreement, but a growing consensus was emerging that a
protocol to limit ozone-depleting substances was warranted and differences
among approaches were beginning to narrow.
The Protocol agreed to on September 16 in Montreal reflects substantial
agreement on the need for a global response to the threat of ozone depletion.
Key provisions in the Protocol include the following:
o The production and consumption of CFG-11, -12, -113, -114,
and -115, which are all the commercially-produced fully -
halogenated CFCs, is to be limited.
o Consumption levels for the above CFCs are frozen at 1986
levels beginning the first day of the seventh month after the
conditions for entry into force are satisfied. Consumption
is defined as production plus imports minus exports.
o Consumption of the above CFCs is reduced to 80 percent of
1986 levels beginning July 1, 1993, and to 50 percent of 1986
levels beginning July 1, 1998.
o Production levels of the specified CFCs are reduced according
to the same schedule, but a 10 percent increase is permitted
for the purposes of exports to parties who are developing
nations with low levels of consumption of controlled
substances or for industrial rationalization. The allowance
increases to 15 percent beginning in mid-1998.
o Production and consumption of Halon 2402, 1301, and 1211 are
to be frozen at 1986 levels beginning three years after entry
into force. A 10 percent production increase is permitted as
specified above.
o Imports of bulk CFCs and halons from States not party to the
protocol are banned one year after entry into force.
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1-8
The parties shall develop a list of products containing CFCs
and halons whose importation would be banned from non-
parties in the fourth year after entry into force.
The parties shall determine within five years of entry into
force the feasibility of banning or restricting imports from
non-parties of products produced with but no longer
containing the controlled substances.
Developing nations with consumption levels under 0.3
kilograms per capita are permitted to increase consumption up
to that level for a period of ten years from entry into
force, after which they must phase down their production and
consumption of controlled substances.
In 1990 and at least every four years thereafter, the parties
shall assess the need for modifying the control requirements
contained in the Protocol to reflect the available
scientific, economic, environmental, and technical
information.
BASIS FOR EIS PREPARATION
The National Environmental Policy Act (NEPA) (Section 102), and Executive
Order 12114 require the preparation of an EIS for major Federal actions that
could significantly affect the environment including the environment of the
global commons outside the jurisdiction of any nation (Sections 2-3(a) and 2-
4(b)(i)). Guidance published by the Council on Environmental Quality
specifically includes major Federal actions that significantly affect
stratospheric conditions in areas outside the jurisdiction of any nation as an
example of the global commons (44 FR 18722; March 29, 1979).
1984 Notice of Intent
The State Department and EPA anticipated in 1984 that negotiations on
stratospheric ozone protection would result in the successful completion of a
control protocol. In August 1984 they published a notice of intent to prepare
an EIS (49 FR 30823; August 1, 1984).
The 1984 notice of intent reviewed the history of scientific research on
threats to the stratospheric ozone layer, and the ongoing attempts to negotiate
a protocol. Based on the anticipated design of the protocol, the notice
presented preliminary lists of alternatives and issues to be evaluated in the
EIS.
The preliminary list of alternatives to be considered reflected the
positions advocated at the time by the parties to the negotiation: (1) no
protocol; (2) global ban on non-essential CFC use in aerosols; (3) phased-in
controls on non-essential CFC use in aerosols; (4) limits on other uses or
substances; and (5) other options such as production capacity limits.
The preliminary list of issues to be evaluated in the EIS included:
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1-9
o Relationship of CFG emissions and other atmospheric
perturbants to depletion of ozone and to changes in the
vertical column of ozone in the earth's atmosphere.
o Effects of alternative Protocol options on potential
increases in UV-B radiation.
o Potential health effects.
o Potential plant and animal effects, including effects on
marine organisms and crops.
o Potential damages to materials.
o Potential quality of life impacts.
o Effects of alternative Protocol options on potential changes
in climate.
o Socio-economic effects of alternative Protocol options.
o Costs associated with potential effects on human health, food
crops, aquatic life, and materials damage.
o Potential effects associated with using [CFG] substitutes.
o Potential impacts on U.S. trade and foreign subsidiaries.
To encourage public participation in the EIS preparation, in the notice of
intent, the State Department and EPA invited written comments on the scope of
the EIS and held a public "scoping meeting" on August 13, 1984, at the State
Department headquarters.
Written comments on the scope of the EIS were submitted by 4 parties.
Attendees at the August 1984 scoping meeting included 15 non-governmental
individuals representing various industrial and environmental groups and one
foreign nation. Comments on the scope of the EIS included both administrative
and technical issues (see Appendix A to Chapter 1). These comments and changes
that have occurred in the negotiations since that time were reflected in the
development of EPA's revised notice of intent for the EIS preparation, which
was published in August 1987 (52 FR 29110; August 5, 1987).
1987 Revised Notice of Intent (NOI)
As explained above, the 1984 international negotiations resulted in the
adoption of the Vienna Convention for the Protection of the Ozone Layer, but
did not result in a control protocol. After the year of research and review,
negotiations on a control protocol resumed, but the discussions differed
markedly from previous negotiations. To reflect this change, a revised notice
of intent was prepared for an EIS to review a potential control protocol (52 FR
29110; August 5, 1987).
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1-10
The preliminary list of issues to be addressed in the EIS is similar to
that specified in the 1984 notice of intent: effects of CFCs and other trace
gases on ozone; impact of protocol options on possible changes in a range of
human health and environmental conditions; and the socioeconomic impacts of
limiting ozone-depleting chemicals. Because considerably more information
about these topics had become available since the 1984 notice, it would have to
be incorporated into the EIS. In addition, based on comments received during
the 1984 scoping session, the revised NOI specified that the EIS would
explicitly take into account the potential health, safety and energy impacts
from actions to reduce the use of CFCs and halons.
The revised NOI listed alternatives to be examined in the EIS which
reflected the altered focus of the recent negotiations and the resulting terms
of the Montreal Protocol. These alternatives also reflected comments received
from the public at the 1984 scoping session:
o no international action;
o no international action, but the U.S. acts unilaterally;
o an international protocol providing for:
-- freeze at 1986 levels
-- 20% reduction
-- 50% reduction
-- 85% reduction.
The EIS would also ex£ _:ine the timing, participation, and coverage of controls
(e.g., CFC-11,-12,-113,-114, and -115 and Halon 1211 and 1301) in various
combinations. Some nations had proposed that fewer chemicals be included under
the protocol, while others had sought broader coverage (e.g., adding HCFC-22
and methyl chloroform). Other issues that would be examined in the EIS
included the impact of:
o trade provisions to restrict trade of bulk ozone-depleting
chemicals, or products made with or containing CFCs, between
parties to the protocol and non-parties; and
o provisions concerning the treatment of developing countries
which are not yet large consumers or producers of CFCs.
Written comments on the revised scope of the EIS were submitted by 26
organizations. Comments and responses to the 1984 NOI and scoping session, and
the 1987 updated NOI are included as Appendix A to Chapter 1.
ORGANIZATION OF THIS EIS
The remainder of this EIS is organized as follows:
o Chapter 2: Description of Affected Environment. This chapter
summarizes scientific evidence concerning ozone depletion. The
chapter describes historical changes in concentrations of ozone-
-------
1-11
depleting compounds in the stratosphere and the modeling approaches
that have been used to predict stratospheric ozone modification.
Potential human health and environmental effects associated with ozone
depletion are identified.
Chapter 3: Description of Alternatives. This chapter defines the
control levels that are analyzed in this EIS. The chapter details the
provisions of the Montreal Protocol, including chemical coverage,
stringency, and trade provisions. The chapter then defines a range of
control levels that could be undertaken. Also considered are a series
of sensitivity cases that vary important assumptions in the analysis,
such as levels of international participation in controls.
Chapter 4: Health and Environmental Consequences of Alternatives.
This chapter, presents estimates of the health and environmental
impacts of ozone modification, including effects on skin cancers,
cataracts, sea level, crop production, aquatic organisms, tropospheric
ozone, and polymers. Estimates are presented for the U.S. for the
control level alternatives identified in chapter 3.
Chapter 5: Socio-Economic Costs of Alternatives. This chapter
presents estimates of social costs for the U.S. associated with the
alternative control levels. Cost estimates are shown for each control
level under a range of assumptions regarding the manner in which the
major CFC-consuming industries in the U.S. respond to regulatory
restrictions. The chapter also presents a side-by-side comparison of
social costs and human health effects for each control level analyzed
in this EIS.
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1-12
REFERENCES
Chemical Manufacturers Association (CMA) (1987), Production. Sales and
Calculated Release of CFC-11 and CFC-12 through 1986. CMA, Washington, D.C.
Hammitt, J.K., and K.A. Wolf, F. Canm, W.E. Hooz, T.H. Quinn, and A. Bamezai
(1986), Product Uses and Market Trends for Potential Ozone-Depleting
Substances. 1985-2000. R-3386-EPA, The RAND Corporation, Santa Monica, CA.
Molina, M.J., and F.S. Rowland (1974), "Stratospheric Sink for
Chlorofluoromethanes: Chlorine Atorn-Catalysed Destruction of Ozone," Nature.
249, pp. 810-812.
United States Environmental Protection Agency (U.S. EPA) and United Nations
Environment Programme (1986), Effects of Changes in Stratospheric Ozone and
Global Climate. Volumes 1-4.. U.S. EPA, Washington, D.C.
U.S. EPA (1987a), Assessing the Risks of Trace Gases that can Modify the
Stratosphere. U.S. EPA, Washington, D.C.
U.S. EPA (1987b), Regulatory Impact Analysis: Protection of Stratospheric
Ozone. U.S. EPA, Washington, D.C.
United States International Trade Commission (USITC) (1961-1987), Synthetic
Organic Chemicals. USITC, Washington, D.T.
United Nations Environment Programme (UNEP) (1985), Vienna Convention for the
Protection of the Ozone Layer. UNEP, Geneva, Switzerland.
Wolf, K.A. (1980), Regulating Chlorofluorocarbon Emissions: Effects on
Chemical Production. N-1483-EPA, The RAND Corporation, Santa Monica, CA.
World Meteorological Organization (WMO) (1986), Atmospheric Ozone 1985:
Assessment of our Understanding of the Processes Controlling its Distribution
and Chanee. WMO Report No. 16, WMO, Geneva, Switzerland.
-------
1-13
APPENDIX A TO CHAPTER 1
COMMENTS AND RESPONSES TO ANNOUNCEMENT OF EIS
I. COMMENTS ON THE 1984 NOTICE OF INTENT
Written comments on the scope of the EIS were submitted by four
organizations: the Air Conditioning and Refrigeration Institute; the Alliance
for Responsible CFC Policy, Inc.; the Fluorocarbon Program Panel of the
Chemical Manufacturers Association; and the World Resources Institute.
Comments on Administrative Procedure
Comment: The Alliance for a Responsible CFC Policy (Alliance) commented that
preparation of the EIS should precede U.S. participation in
international negotiations to formulate a control protocol, and
that a "programmatic" EIS that reviews the overall stratospheric
ozone protection strategy of the State Department and EPA is
required.
Response: As required by NEPA and E.G. 12114, preparation of the EIS precedes
the final Federal action which, in this case, is transmittal of the
Protocol to the Senate. The EPA announced its overall
stratospheric protection plan in the Federal Register, in January
1986 (51%FR 1257; January 10, 1986). The plan provided for
extensive opportunities for public participation in EPA's research
and review of stratospheric issues. This EIS document draws
extensively from the public input received during that process.
This legislative EIS is being prepared pursuant to NEPA guidelines.
Comment: The Alliance requested full public participation in preparation of
the EIS.
Response: As stated above, throughout the course of its stratospheric ozone
protection negotiations, the State Department and EPA continually
sought and received public review and comment. A 45 day comment
period is being allowed for public comment in the EIS.
Comments on the Scope of the EIS
Comment: The Alliance and Fluorocarbon Program Panel of the Chemical
Manufacturers Association (FPP) requested inclusion of another
policy alternative, i.e., accelerated research and monitoring to
evaluate the future need for development of a control protocol.
Response: This alternative is included within the alternative: No controls.
Comment: The Alliance and FPP noted that the science indicated no imminent
threat to the stratosphere from current levels of CFC emissions and
from realistic multiple-perturbant scenarios of trace gases.
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1-14
Response: The EIS reviews the state of the science on stratospheric issues.
It relies heavily on the international scientific assessment
coordinated by the World Meteorological Organization, United
Nations Environment Programme, and National Aeronautics and Space
Administration. The EIS gives full consideration to scientific
uncertainty and a range of trace gas scenarios.
Comment: The Alliance noted that monitoring has not shown any observed
depletion of total column ozone.
Response: The EIS addresses recent findings of global and regional ozone
monitoring and their role in decision making.
Comment: The Alliance and World Resources Institute (WRI) noted that the EIS
should consider all trace gases that affect the stratosphere. WRI
urged the consideration of synergistic ozone-climate effects.
Response: The EIS considers a broad range of substances that affect the
stratosphere, and reviews linkages between the stratosphere and
global climate.
Comment: Commenters focused on the EIS review of the effects of
stratospheric ozone depletion. The Alliance questioned the
scientific evidence involving several effects areas including
immune suppression, melanoma skin cancer, and ecosystem effects.
In addition, it noted that the benefits of projected UV-B decreases
from ozone increases should be considered.
Response: The EIS reviews current knowledge and uncertainties in all health
and environmental effects areas identified. The EIS analysis of
effects draws heavily from the recently completed EPA risk
assessment, which was reviewed by the EPA's Science Advisory Board.
Comment: The FPP requested that all effects be quantified.
Response: The EPA's risk assessment, and its review .by the Science Advisory
Board, noted that several potential effects of stratospheric change
are not quantifiable, but are significant enough to deserve
inclusion in analyses of stratospheric protection. The EIS follows
this view, and discusses both potential quantitative and
qualitative health and environmental impacts.
Comment: WRI noted that the EIS should evaluate the potential for future
growth in CFC emissions and consider the effects of non-linear
ozone response to such growth.
-------
1-15
growth in CFCs and other trace gases. This issue was extensively
reviewed in workshops sponsored by the EPA and UNEP. Non-linear
response to chlorine is no longer believed likely except under high
chlorine levels. This issue is evaluated in the EIS discussion of
atmospheric effects of CFCs and other trace gases.
Comment: WRI noted that the EIS should evaluate strategies that encourage
innovation among users of CFCs, as this may lower regulatory
compliance costs.
Response: The effects of the protocol on innovation is implicitly considered
in the development of the controls data base used in preparing the
EIS.
Comment: WRI noted that analysis is needed of the risks of inaction versus
waiting for more scientific certainty.
Response: The preliminary alternatives to be considered include both cases,
and the relative risks of each type of action is evaluated in the
EIS.
Comment: WRI noted that the EIS should evaluate effects of a U.S. action on
international cooperation.
Response: This potential effect will be modelled in the evaluation of the
effects of protocol participation on global use of CFCs.
II. COMMENTS ON THE 1987 NOTICE OF INTENT
Written comments on the revised scope of the EIS were submitted in 1987 by
26 organizations. Of these commenters, 21 represented manufacturers and
distributors of halon fire protection systems: Fire Defense Equipment Company,
Inc.; Protection Technologies, Inc.; .Engineered Data Environments, Inc.;
Capital Fire Protection Co.; National Association of Fire Equipment
Distributors, Inc.; Fire Suppression Systems Association; Fire Equipment
Manufacturers Association, Inc.; National Fire Protection Association; Amerex;
Fike Fire Suppression Systems; Pryotronics; Megacity Fire Protection; G.S.
Parsons Co.; Fuller Engineering Sales Corp.; Northern Fire & Safety Inc.;
National Fail Safe; Ellenco, Inc.; Henry's Safety Supply Company; ICI Specialty
Chemicals; Steven Environmental Systems, Inc.; and Taylor/Wagner, Inc.
Other organizations submitting comments were the E.I. duPont de Nemours &
Company, Inc.; Alliance for Responsible CFC Policy, Inc.; Illinois
Environmental Protection Agency; and the Environmental Defense Fund.
Comoents on Control of Halon Production and Emissions
Comment: Commenters from the halon community reviewed the relative
advantages of halons as fire extinguishing agents.
-------
1-16
Response: The EIS evaluates the costs of alternative technologies to reduce
halon consumption and emissions. EPA has worked with the halon
industry to ensure that the alternatives considered will meet all
relevant health and safety criteria.
Comment: Commenters noted that quantities of Halon 1301 are contained in
total flooding systems and are usually released only during fires.
Emphasis should be placed on controlling emissions rather than
production.
Response: The alternatives evaluated in this EIS generally track those
contained in the Montreal Protocol, which mandates controls on
production. EPA recognizes the importance of limiting unnecessary
halon emissions and will continue to work with the halon industry
to limit such emissions. It is anticipated that the protocol
members will review the halon provisions in the future.
Comment: Several commenters noted the considerable effort undertaken by the
halon community to reduce unnecessary emissions.
Response: EPA and the Department of State appreciate and encourage such
voluntary efforts'.
Comment: Several commenters noted that comprehensive data on halon use and
emission patterns have not yet been collected. In addition, many
commenters urged that a decision on control of halons be postponed
until 1990.
Response: In evaluating halon use, emissions and control technologies, EPA
has successfully worked with the halon community to collect a
considerable amount of data which are sufficient for regulatory
analysis. To set a future date for controls in the Protocol would
have encouraged expansion of halon use and discouraged the
voluntary efforts noted above. The Protocol requires only a freeze
on halons at 1986 levels beginning three years after entry in
force, thus providing ample opportunities for the parties to
consider additional or alternative control strategies as further
information becomes available.
General Comments
Comment: E.I. DuPont de Nemours & Company, Inc. (DuPont) and the Alliance
for Responsible CFC Policy, Inc., (Alliance) requested that the
EPA's technical basis for decision making, including its risk
analysis and regulatory impact analysis, be published in advance of
U.S. participation in international negotiations on stratospheric
protection and preparation of this EIS.
Response: On December 1, 1987, EPA published its final risk assessment and
regulatory impact analysis. During the research and preparation of
-------
1-17
these documents, EPA requested and received considerable public
comment and review.
Comment: DuFont and the Alliance requested clarification of the EIS's
treatment of observed seasonal losses of ozone in Antarctica. They
noted that scientific analysis of this phenomenon does not support
conclusions about its causes and effects or its relevance to global
ozone levels.
Response: EPA and the Department of State agree that the global relevance of
the Antarctic hole is uncertain. In this EIS, global ozone levels
are projected using models that do not attempt to replicate the
Antarctic ozone losses.
Comment: DuPont and the Alliance noted that current production levels of
CFCs and halons do not pose a significant risk to future ozone
levels. They suggested that a scenario of low CFG and'halon growth
be included.
Response: The EIS evaluates the sensitivity of future ozone levels to various
scenarios of baseline CFC and halon use. One such scenario assumes
long-term growth in CFCs of approximately 1.2 percent per. year.
Comment: The Alliance noted that atmospheric models project long-term
increases of ozbnf= for scenarios of low CFC growth. It suggested
that the EIS quantify the benefits of ozone increases.
Response: The effects models used in this EIS quantify both the effects of
ozone decreases and ozone increases.
Comment: DuPont questioned the need to evaluate "economic and trade
provisions unless they account for identifiable differences in
emissions."
Response:' Economic and trade provisions will play an important role in
determining global production levels of CFCs and halons, and thus
are evaluated in this EIS.
Comment: DuPont and the Alliance noted that the EIS should consider the
health, safety and environmental effects of substitute chemicals
and control technologies.
Response: Chapter 5 of this EIS, "Socio-Economic Costs of Alternatives,"
discusses these effects.
Comment:
The Alliance suggested that the EIS evaluate the benefits of
-------
1-18
continued use of CFCs and other chlorinated compounds with
relatively low ozone depletion potentials.
Response: The EIS alternatives consider controls on the fully-halogenated
CFCs and halons. Controls on compounds with lower ozone depletion
potentials such as HCFC-22 and methyl chloroform are not evaluated.
Comment: Dr. Michael Reischel of the Illinois Environmental Protection
Agency noted that the EIS should focus on the products of CFC
photodissociation, particularly chlorine.
Response: The scientific assessments and models used in this EIS pay close
attention to atmospheric chlorine chemistry and other chemical
processes.
Comment: Dr. Reischel suggested that the EIS specifically address
uncertainties regarding the effects of clouds on atmospheric
processes.
Response: EFA's scientific risk assessment relies heavily on the
comprehensive three-volume report recently prepared by the World
Meteorological Organization (WMO, 1986). This report specifically
addresses the role of clouds. Explicit evaluation of cloud
processes is not warranted in this EIS.
Comment: Reischel noted that the EIS should consider a range of chemical
coverage options.
Response: The EIS explicitly evaluates alternative chemical coverage options.
Comment: The Environmental Defense Fund forwarded a journal article
containing its thoughts on stratospheric protection.
Response: The EPA and Department of State appreciated the opportunity to
review this article.
-------
CHAPTER 2
DESCRIPTION OF AFFECTED ENVIRONMENT
ABSTRACT
Measurements indicate that atmospheric concentrations of trace gases that
influence stratospheric ozone have been increasing. Scientific models of the
atmosphere project that if these trends continue, the concentration and
vertical distribution of stratospheric ozone will be altered. Stratospheric
modification would have significant effects on human health, welfare and the
environment. Increases in UV-B radiation due to stratospheric ozone depletion
could increase the incidence of skin cancer, cataracts, and systemic immune
suppression in humans, damage crops and aquatic organisms, and accelerate the
degradation of outdoor materials and the formation of ground-level pollution.
Increases in these trace gases along with changes in the vertical distribution
of ozone would contribute to global climate change.
This chapter discusses the scientific evidence available today concerning
the changing atmosphere and the potential effects of these changes. The first
section details the measured changes in the atmospheric concentrations of
various compounds, the lifetimes of these compounds, and the modelling of the
effects on stratospheric ozone due to these compounds. The last section
discusses potential human health and environmental effects of stratospheric
modification, including skin cancer, cataracts, plants, aquatics, and global
climate change.
EVIDENCE OF A CHANGING ATMOSPHERE
Recent measurements indicate that the concentrations of many trace gases
are increasing throughout the lower atmosphere (the troposphere). Some of
these gases are slowly transported to the upper atmosphere (the stratosphere)
and become involved .in chemical reactions that affect the creation and
destruction of ozone. They also can play an indirect role in the stratosphere
by influencing the atmosphere's radiative balance (temperature) or dynamics.
1. Tropospheric Concentrations of Potential Ozone-Depleting Trace Gases
Chlorofluorocarbons (CFCs) are anthropogenic gases used in a variety of
consumer goods and industrial processes. Measurements show that the
atmospheric concentrations of the two most widely used CFCs, CFC-11 and
CFC-12, have more than doubled in the past ten years (Rasmussen and Khalil,
1986). Recently, their concentrations have increased at 5 percent per year
(Exhibit 2-1 and Exhibit 2-2) (WHO, 1986). Measurements show that
concentrations of other CFCs are also increasing: CFC-113 at 10 percent per
year (Exhibit 2-3) (Rasmussen and Khalil, 1982) and HCFC-22 at 11 percent per
year (Exhibit 2-4) (Rasmussen and Khalil, 1982). Concentrations of other
-------
2-2
EXHIBIT 2-1
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF CFC-11 (CFC13)
era., in AOIWOU. imukho
..
n.'M'ii"1
itn i*n
era., m CAK MCAMS. omaoN
1 110
J
i'-
i1"
5 in
Hill'"1
iiiuH.Hll1"""'
„,."' "'"
.iiini11'
! ! 1 1 •
itn itn 100 not <*a
CRL, in MAGQEO POINT. SAM8AOOS
5 snl
iaool
l'-j ,.„..'!
i in niil1"
1 Jllill " "
,.,»
itn ttn
CTCU in MINT MATATULA. AMCMICAN SAMOA
1"
*'«
l III
!'
ili'
Mill"
'llll
itn itn mo
cm, in CAM mat. TASMANU
Average concentrations of CFG- 11 are increasing at approximately
five percent per year. Data are from the Atmospheric Lifetime
Experiment .
Source: World Meteorological Organization, 1986; Figure 3-2.
-------
2-3
EXHIBIT 2-2
*
MEASURED TwrPEASRS IN TROFOSFHERIC CONCENTRATIONS
OF CFC-12
CF.CL, AORIOOIE. IRELAND
I""
a-:
I HI 1*M
CP.CL, CAPE MEARES. OREO ON
tin it»
CF.CL. RAGGED POINT. BARBADOS
i»:
J 110 i
ttlt t«7f
iwa t«u t*
CF.CL, POINT MATATULA. AMERICAN SAMOA
l»
a"e
i "•
a no
: **o
i
. i • 1 1 1 1 •
,i in'
1M1 1*U
CF.O.I CAPE GRIM. TASMANIA
r
.1"
Average concentrations of CFC-12 are increasing at approximately
five percent per year. Data are from the Atmospheric Lifetime
Experiment.
Source: World Meteorological Organization, 1986; Figure 3-3.
-------
2-4
EXHIBIT 2-3
MEASURED INCREASES IN TRDPOSPHERIC CONCENTRATIONS
OF CFC-113 (C2Cl3F3)
1975
1977
1979
1981
1983
Average concentrations of CFC-113 are increasing at approximately 10
percent per year.
Source: Rasmussen and Khalil, 1982.
EXHIBIT 2-4
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF HCFC-22 (CHC1F2)
3
S*
a
I
20
1975
1977
1979
1981
1983
Average concentrations of HCFC-22 are increasing at approximately 12
percent per year.
Source: Rasmussen and Khalil, 1982.
-------
2-5
chlorinated compounds are also increasing: carbon tetrachloride and methyl
chloroform are increasing at 1 percent per year (Exhibit 2-5) and 7 percent
per year (Exhibit 2-6) (WMO, 1986).
Halons are brominated compounds used in fire-fighting applications.
Until recently, researchers had not attempted to measure trends in
concentrations of these trace gases. Khali1 and Rasmussen (1985) report that
the concentrations of Halon 1211 are increasing at 23 percent per year
(Exhibit 2-7). Measurements of Halon 1301 show similar increases (Rasmussen,
personal communication).
Nitrous oxide (N20) is emitted from natural sources, fossil fuel
combustion, and fertilizer use. Ice core measurements have established that
N2<3 concentrations began to rise concurrent with the Industrial Revolution
(Pearman et al., 1986). Recent measurements indicate that N20 concentrations
are increasing at approximately 0.2 percent per year (Exhibit 2-8) (Weiss,
1981; WMO, 1986). Depending on the levels of N20 and chlorine species, this
gas could either increase or decrease ozone levels.
2. Tropospheric Concentrations of Potential Ozone-Increasing Trace Gases
Carbon dioxide (C02) is emitted from natural sources and fossil fuel
combustion. Ice core data show that atmospheric concentrations of 002 began
to increase concurrent with the Industrial Revolution (Pearman et al., 1986).
Direct measurements made at Mauna Loa Observatory in Hawaii (Keeling and
GMCC/NOAA, n.d.) indicate that since 1958, concentrations have risen by ten
percent. Recently, they have increased at approximately 0.5 percent per year
(Exhibit 2-9).
Methane (CH^.) has both natural and anthropogenic sources. As with N20
and C02, atmospheric concentrations appear to have begun to increase 150 to
200 years ago (Pearman et al., 1986). Recent analyses indicate that CH4
concentrations are increasing at 0.017 parts per million per year (Exhibit 2-
10) (Blake et al., 1982; Rinsland, Levine and Miles, 1985; and Rowland,
personal communication).
3. Trace Gas Lifetimes and Transport to the Stratosphere
Because of the long atmospheric lifetime of most of these gases,
increases in their tropospheric concentrations will influence their
stratospheric abundances because their tropospheric concentrations form a
growing reservoir for future increases in stratospheric concentrations. The
number of trace gas molecules that eventually reach the stratosphere depends
on the trace gas's source strength and removal processes.
Unless a rapid process exists for its removal, a trace gas molecular
released at the surface becomes distributed throughout the troposphere. The
time scale for local vertical mixing is a few weeks; that for east-west mixing
is a few months; and that for exchange between the northern and southern
hemisphere is one to two years (NAS, 1976). Thus, CFCs released in the
-------
2-6
EXHIBIT 2-5
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF CARBON TETRACHLORIDE (CC14)
CCU ADRIOOLE. IRELAND
llhlllllllll'1"1'"1"1 .,,,,••,""'.,,Hi
1(7* 1*7* 1MO 1M1 'Ml KM 1*M
CCU CAPC MEARES. OREGON
9 "»
i130
I'll
,,,,,,nil • |,mi,,nil "
1*7*
CCU RAGGED POINT. BARBADOS
I-
l-j,,,,.,.!, ' ' '"""""
j 1101' ' •I
1170 l»7t
CCU POINT MATATULA. AMERICAN SAMOA
I"
J 110
J1OO
•0
[ 1 1 1 1 III'* ' 1
1MJ 1*M
CCU CAP6 GRIM. TASMANIA
i1"
I"°
5 MO
I"
Average concentrations of carbon tetrachloride are increasing at
approximately one percent per year. Data are from the Atmospheric
Lifetime Experiment.
Source: World Meteorological Organization, 1986; Figure 3-5.
-------
2-7
EXHIBIT 2-6
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF METHYL CHLOROFORM (GH3CC13)
CH.CCU. AORICOLE. IRELAND
l-
«••
i'»
,,.
J.,,0
1*71 1171
CH.CCt. CAPE MEARES. OREGON
J, 30.
110
I ll1'1
1MO 1M1
CH.CCL, RAGGED POINT, BARBADOS
..,,„, ..... ,
^iniii in'!;'11 • •'
CH.CCL, POINT MATATULA. AMERICAN SAMOA
Til.
1 110
2 100
• 00
1 70
i( ., ,,,1i""""'1 "
M!,|| '• !'
.
ItTI t»7t
CH.CCL, CAPE GRIM. TASMANIA
i 100
i«
in1
.,!.•••. Ill"" .......
t 1 '
' 1 1 1 '
Average concentrations of methyl chloroform are increasing at
approximately seven percent per year. Data are from the Atmospheric
Lifetime Experiment.
Source: World Meteorological Organization, 1986; Figure 3-4.
-------
2-8
EXHIBIT 2-7
MEASURED INCREASES IN TROFOSFHERIC CONCENTRATIONS
OF HALON 1211 (CF2ClBr)
1979
1980
1981
1982
1983
1984
Measurements from South Pole. Average concentrations of Halon 1211
are increasing at approximately 23 percent per year.
Source: Khali1 and Rasmussen, 1985.
-------
2-9
EXHIBIT 2-8
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF NITROUS OXIDE (N20)
AORIOOIE. IRtlANO
III"1
lit,, ,11)1111 I'HIIIIHIMI,
i—;
1*71' i»7» IMO IMI ' ini i*u '
-------
2-10
EXHIBIT 2-9
MEASURED INCREASES IN TROPOSPHERJC CONCENTRATIONS
OF CARBON DIOXIDE (CO2)
350
315
^m
1 310
o
>
5
3 335
2 330
5
•n^
5
§ 3'
§
i_i
g
M 320
315 -
310
1955
1960
1965
1970
1975
1980
Monthly measurements from Mauna Loa, Hawaii. Data collection began
in 1958 with the International Geophysical Year. Since that time,
concentrations have increased 10 percent.
Source: Keeling, C.D., and GMCC/NCAA, unpublished.
-------
2-11
EXHIBIT 2-10
MEASURED INCREASES IN TROPOSPHERIC CONCENTRATIONS
OF METHANE
1.65 -
O
.1.60
I
I
s
8
1.56
1.50
1977
1979
1981
1983
1985
Average concentrations of methane are increasing at approximately
0.017 ppm per year.
Source: Rowland, in NASA, 1986; Figure 5.
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2-12
Northern Hemisphere are uniformly mixed through both hemispheres within two
years.
Trace gases can be removed from the troposphere by a number of processes
that occur at the earth's surface or in the atmosphere. Physical processes,
such as absorption of C02 by the oceans, are one type of removal process.
Chemical processes are another type. An important example of chemical removal
is the reaction of the OH radical with trace gases such as methyl chloroform.
CFCs are stable gases that have no significant removal processes in the
troposphere (NAS, 1983), other than transport to the stratosphere. This
transport occurs in large scale motion of air masses, which is a relatively
slow process.
Based primarily on scientific research sponsored by the Atmospheric
Lifetime Experiment, estimates exist for the atmospheric lifetimes of these
chemicals: 75 years for CFC-11 and 111 years for CFC-12 (WMO, 1986). Other
trace gases with long lifetimes include CFC-113 (90 years; NAS, 1984); carbon
tetrachloride (50 years; WMO, 1986); Halon 1211 (25 years; NAS, 1984);
Halon 1301 (110 years; NAS, 1984); and N20 (150 years; WMO, 1986). Their long
lifetimes imply that their atmospheric concentrations would continue to rise
even if emissions were held constant. While an equilibrium would eventually
be reached, it would be at a much higher concentration than current levels.
Exhibit 2-11 shows an example for CFC-12. Given their long atmospheric
lifetimes, it is likely that regardless of their use, CFCs will eventually
migrate to the stratosphere and release their chlorine.
The disequilibrium between sources and sinks for long-lived perturbants
such as CFC-11 and CFC-12 imparts a momentum for stratospheric change --
tropospheric concentrations will continue to rise (and trace gas molecules
will increase in the stratosphere), despite drastic cuts in emissions. A
simplified, first-order model of CFC emissions and concentrations demonstrates
that to hold tropospheric concentrations of CFC-11 and CFC-12 constant would
require an 80 percent cutback in CFC-11 emissions and an 85 percent cutback in
CFC-12 emissions. Exhibits 2-12 and 2-13 show estimates of concentrations for
CFC-12.
Other tropospheric compounds have shorter lifetimes, and their future
concentrations are thus more sensitive to current rates of emissions. These
shorter-lived compounds include HCFC-22 (20 year lifetime; NAS, 1984); methyl
chloroform (6.5 year lifetime; WMO, 1986); and CH4 (11 year lifetime; WMO,
1986). While these lifetimes are short relative to CFCs, they are long
compared to gases such as carbon monoxide, which has a 16 week average
lifetime (Ramanathan et al., 1985). The main removal process for HCFC-22,
methyl chloroform, and CH4 is their chemical reaction with the OH radical in
the troposphere.
While the vertical distribution of trace gases in the troposphere is
relatively uniform, stratospheric concentrations of CFCs and other trace gases
rapidly decrease with altitude (WMO, 1986). This is because the structural
bonds of these trace gases are broken apart by high-energy solar radiation in
-------
2-13
EXHIBIT 2-11
CFC-12: CONSTANT EMISSIONS
(•ill kg)
(A)
500
400
300
200
100
1930 1985 2100
CFC-12: ATMOSPHERIC CONCENTRATIONS
(ppbv)
(B)
1.6
1.2
0.8
0.4
0
1930
2100
If future emission of CFC-12 were held constant at today's levels
(A), atmospheric concentrations would continue to rise for over 100
years (B). Computed with simplified model of source and loss terms.
Source: EPA, 1987, Exhibit 2-15.
-------
(A)
500
2-14
EXHIBIT 2-12
CFC-12: EMISSIONS REDUCED 85%
(.ill kg)
400 •
300
200
100
1930 1985 2100
CFC-12: ATMOSPHERIC CONCENTRATIONS
(ppbv)
(B)
0.40 ••
0.30 '
0.20 -
0.10 -
1930
1985
2100
A reduction of 85% in CFC-12 emissions (A) would be required to hold
concentrations constant (B). Computed with simplified model of
source and loss terms.
Source: EPA, 1987, Exhibit 2-16.
-------
2-15
EXHIBIT 2-13
CFC-12: ATMOSPHERIC CONCENTRATIONS FROM
DIFFERENT EMISSION TRAJECTORIES
§
s
a
3
&
s
1 1
!
i
0
Constant
emissions
15% Cut
50% Cut.
85% Cut
1930
1985
2100
For CFC-12, holding emissions constant at 85% of today's level (a 15
percent cut), would allow concentrations to increase by a factor of
four. Only a reduction of emissions to 15 percent of today's level
(an 85 percent cut) could hold concentrations constant. Computed
with simplified model of source and loss terms.
Source: EPA, 1987, Exhibit 2-17.
-------
2-16
the stratosphere. Stratospheric composition is influenced by the products of
this dissociation: chlorine (a product of CFCs, other chlorinated compounds,
and Halon 1211), bromine (a product of Halon 1211 and Halon 1301), and
nitrogen (a product of ^0), which interact through various chemical cycles
with ozone.
4. Modelling Stratospheric Ozone Changes
The abundance of ozone is controlled by its production and loss rates.
The effect of chlorine, bromine, and nitrogen is to increase the loss rate of
ozone through catalytic chain .reactions. A simplified schematic of this cycle
for chlorine is:
Cl + 03 > CIO + 02
CIO + 0 > Cl + 02
Net 0 +03 > 02+02
This set of reactions is called "catalytic" because the chlorine atom (Cl)
first reacts to destroy ozone (03), but then is freed at the end of the chain.
The significance of this type of catalytic cycle is that small amounts of
chlorine, bromine, or nitrogen can destroy substantial amounts of ozone.
To estimate the stratosphere's response to increasing concentrations of
trace gases requires modelling the physical and chemical forces that influence
the catalytic cycles that control ozone abundance. Scientists have developed
mathematical models that attempt to simulate these processes.
One-dimensional atmospheric models are the most widely used tools for
investigating stratospheric change. One-dimensional models include detailed
representations of chemical reactions among atmospheric species, and consider
variations by altitude (the "one-dimension" that is represented). One-
dimensional models do not attempt to represent latitudinal or longitudinal
variations, but instead rely on global averages.
Two-dimensional models also include latitudinal and seasonal variations,
and are thus potentially more useful tools for predicting the patterns of
stratospheric change on the earth's environment. The computer resources
required for these models are intensive, however, and only one two-dimensional
model has thus far been developed that can produce time-dependent projections.
No three-dimensional models with complete chemistry yet exist.
The structure and outputs of the major one-dimensional models used to
assess stratospheric modification have been extensively reviewed, most
recently at a workshop sponsored by the United Nations Environment Programme,
WHO, NASA, and others. Current one-dimensional models project a 5-9 percent
depletion for the equilibrium concentrations of chlorine that would result
from constant emissions of CFCs at 1977 levels. While useful for
intercomparing models, these values cannot be used to assess the risks of
depletion in an atmosphere in which CFCs and other gases, such as C02, CH4,
and N20, are all changing.
-------
2-17
One-dimensional models predict that average column ozone will decrease if
CFC emissions continue to rise from current levels, even if concentrations of
C02, CH4, and ^0 continue to rise at current rates -- for a 2.5 percent
growth of CFCs, one-dimensional models predict over a 25 percent depletion by
2075 (Exhibit 2-14) (Connell andWuebbles, 1986).
Two-dimensional models used in steady state analyses indicate that ozone
depletion will exceed the global average at latitudes greater than 40°N,
especially in the spring season (WHO, 1986).
Time-dependent simulations of stratospheric change using a 2-D model
predict that depletion over 4 percent will occur at some latitudes for all
cases of positive growth in CFC emissions. A time-dependent 2-D model
analysis with CFC emissions growing at 3 percent per year and other trace
gases increasing at observed rates -- CH4 concentrations at 1 percent per
year, ^0 concentrations at 0.25 percent per year, and C02 concentrations at
0.6 percent per year -- projects annual average depletion at 40 degrees north
of 2 percent by 2000 and 6 percent by 2030. At 50 degrees north depletion is
projected to be 2.7 percent by 2000 and 7.8 percent by 2030. At 60 degrees
north depletion is projected to be 3.5 percent by 2000 and 9.5 percent by 2030
(Exhibit 2-15). Springtime depletion would be higher (Isaksen, personal
communication).
The extent to which models reproduce observed concentrations wil 1 have a
bearing on the confidence we place in them. Existing discrepancies between
model predictions and the observed atmosphere lower our confidence in the
predictions of one- and two-dimensional models. For example, models do not
correctly reproduce concentrations of ozone in the upper stratosphere (Exhibit
2-16). For other species, however, models do a relatively good job of
reproducing both concentrations and distributions (Exhibit 2-17). Despite
their shortcomings, both the WHO and EPA assessments concluded that current
atmospheric models represent the best tools available for assessing the
implications for ozone levels of trace gas concentrations.
One particular note of caution concerns the apparent discrepancy between
observations and projections of total ozone levels by current models. Based
on past emissions of CFCs, methane, carbon dioxide and nitrous oxides, these
models project that almost no change should be occurring in current total
column ozone levels. However, recent measurements suggest that global column
ozone may have decreased by 3-5 percent during the past 6-8 years. While
additional analysis is required to determine whether this decline falls within
natural variation (e.g., caused by solar cycle, volcanic activity), this
discrepancy raises questions concerning the accuracy of current models. (See
discussion below.)
-------
2-18
EXHIBIT 2-14
TIME DEPENDENT, GLOBALLY-AVERAGED CHANGE IN OZONE
FOR COUPLED PERTURBATIONS
(LLNL 1-D Model)
•Reference Case"
1990 2000 2010 2020 2030 2040 2090 2060 2070 2080
Total column ozone change for "reference case" scenario of trace
gases: -2.5% growth in CFCs, concentrations of CH4 at 1%, ^0 at
0.25%, and CC>2 at - 0.6%.
Source: Connell and Wuebbles, 1986.
-------
2-19
EXHIBIT 2-15
TIME DEPENDENT SEASONALLY-AVERAGED CHANGE IN OZONE
FOR 3% GROWTH IN CFC EMISSIONS AND COUPLED PERTURBATIONS
(IS 2-D Model)
-10
I9«4
1940
2030
2020
Results shown for 3% growth per year in CFC emissions; 1% growth in
CH^ concentrations; 0.25% growth in N20 concentrations, and
approximately 0.5% growth in C02 concentrations. Changes shown for
40°N, 50°N, and 60°N. Temperature feedback considered in model.
Source: Isaksen (personal communication).
-------
2-20
EXHIBIT 2-16
VERTICAL DISTRIBUTION OF THE OZONE MIXING RATIO
IN THE UPPER STRATOSPHERE
US STO ATM
JAN. 30*M
JULY 30 *N
a • 10
VOtUMC NHXINO RATIO Ippnwl
14
The shaded area included 2-D model results obtained for winter and
summer conditions at 30°N. The 03 mixing ratio given by the U.S.
Standard Atmosphere as well as representative observations at 30°N
for January and July are also indicated.
Source: NASA, 1986, Figure 16.
-------
2-21
EXHIBIT 2-17
CIO VERTICAL PROFILES; MODELS VERSUS MEASUREMENTS
40 ~
I
30
25
MODEL PREDICTIONS. 30 "N
_____ SUMMER
- _ . _ . WINTER
MEASUREMENTS
IN-SITU RESONANCE FLUORESCENT
• WEINSTOCX ET AL. 119811
• BRUNEET AL. I198SI
BAUOON.BASED REMOTE
•f- WATERS ET AL. 119811
l-Ot MENZIES 119831
GROUNO-8ASEO REMOTE
r*" BARRETT ET AL. (19851
10
10 •'• 10-'
CIO VOLUME MIXING RATIO
The mean of the in-situ and ground-bases [CIO] data agrees with one-
and two-dimensional predictions to within a factor of two at 25 km
and better at higher altitudes.
Source: NASA, 1986.
-------
2-22
5. Observed Trends in Ozone Concentrations
t
Monitoring of ozone is done with a variety of ground-based and satellite
systems. Until recently, ozone monitoring showed changes that were roughly
consistent with model predictions. Measurements by balloons and Umkehr show 3
percent depletion at mid-latitudes in the upper atmosphere, 1.3 percent
depletion in the lower stratosphere, and 12 percent increases in the lower
troposphere (Exhibit 2-18).
A global network of ground-based Dobson spectrographic instruments has
been operational since 1970. These Dobson instruments convert the measured
irradiance received by the spectrometer into a total column ozone reading.
Readings from each station are combined to represent seasonal and annual
averages. To develop global averages, station values are weighted by area and
averaged.
The latest analyses of Dobson network data show that from 1980 to 1985,
total column ozone decreased by 4 percent. One-quarter of this decrease may
be attributable to fluctuations in solar activity (Angell, 1987). An
independent analysis of the same data found a 0.34 percent per year decrease
in total column ozone from 1978 to 1985 after allowing for the effects of the
solar cycle (Kerr, 1987). However, these decreases ^ccur from a period of
relatively .high levels of ozone which further complicate the determination of
whether a meaningful decrease has occurred.
Measurements of ozone levels have also been made by the Solar Backscatter
Ultraviolet (SBUV) instrument aboard the Nimbus-7 satellite which was launched
in 1978. The SBUV measures solar radiation by wavelength that is scattered
from the atmosphere and compares the amounts with the direct influx from the
sun. Preliminary and unpublished data from SBUV show that total column ozone
decreased about 4 percent from 1978 to 1985, or about 0.5 percent per year.
As discussed above, depletion of this magnitude is substantially greater than
would be predicted by current models based on historical growth in CFCs.
At the current time the scientific community is actively engaged in a
major review of satellite and ground based data to determine whether a trend
in ozone depletion has occurred. EPA in its risk assessment, feels it is
premature to conclude that ground based or satellite data invalidate model
projections. The decreases claimed by some scientists need broader scrutiny
along with their implications for current atmospheric models.
If these decreases in global ozone levels are verified, a second issue
which must be addressed is whether the changes can be attributed to increases
in chlorine concentrations. As noted above, other possible explanations
include natural variations caused by solar cycles or other processes. Until
further analysis is performed to determine what, if any, changes to current
models and theories are necessary, the existing models remain the best
available tools for assessment purposes.
-------
2-23
EXHIBIT 2-18
UMKEHR DECADAL TREND 1970-1980
(Units: percent per decade)
LYH
MB
REINSEL ET AL (1984)
WUEBBLES ET AL (1983)
REINSEL ET AL (1984)
1-2
2-4
4-8
8-16
16-32
-6 -5 -4 -3 -2 -1
Source: NASA, 1986
-------
2-24
Measurements in the Antarctic spring have also recently provided an
additional area of concern. These measurements show that the gradual
depletion that occurred in the mid-1970's over and near Antarctica has given
way to a steep non-linear depletion of approximately 40 percent from 1979 to
1986. The ozone maximum outside Antarctica (between 50"S and 70°S) also
appears to be showing a decline. The depletion of all areas south of 80°S
appears to be 16 percent (Exhibit 2-19).
Models with conventional chemistry do not predict the "Antarctic hole."
Care should be exercised in interpreting the meaning of the phenomenon.
Several hypotheses have been advanced, including anthropogenic chemical
mechanisms (chlorine and bromine), natural chemical mechanisms (NOX and the
solar cycle), and changes in climate dynamics. Preliminary evidence from two
National Ozone Expeditions and from the National Airborne Ozone Expeditions
strongly suggests that chlorine plays a role in observed depletion. However,
additional research is required to determine if the anomalous chlorine
chemistry in Antarctica is unique to that region and whether or not these
seasonal losses directly affect global ozone levels.
POTENTIAL HEALTH AND ENVIRONMENTAL EFFECTS OF STRATOSPHERIC MODIFICATION
Changes in column ozone abundance and distribution and a rise in global
temperature would be expected to harm human health, welfare and t..e
environment.
1. Increases in DV-B Radiation
The stratospheric ozone layer shields the earth's surface from harmful
ultraviolet (UV-B) radiation. A decrease in total column ozone would increase
this radiation, especially at its most harmful wavelengths. A 1 percent ozone
depletion would increase DNA-damaging UV radiation by about 2 percent (NAS,
1984).
2. Skin Cancer
The most common form of skin cancer is non-melanoma skin cancer -- basal
cell carcinoma and squamous cell carcinoma. In the U.S., approximately
500,000 cases of non-melanoma skin cancer occur each year. Eighty percent of
these cases are basal cell, the less severe type of cancer, with a fatality
rate of approximately 0.3 percent. Twenty percent of non-melanoma cases are
the more serious type, squamous cell carcinoma, which has a fatality rate of
approximately 3.75 percent (estimated from data in Scotto, Fears, and
Fraumeni, 1981).
Researchers have demonstrated that UV-B radiation is the primary cause of
non-melanoma skin cancer. Several lines of evidence support this conclusion:
(1) non-melanoma skin tumors tend to develop in sun-exposed sites (e.g., the
head, face and"neck); (2) higher incidence rates occur among occupational
groups subject to greater sun exposure (e.g., outdoor workers); (3) non-
-------
2-25
EXHIBIT 2-19
NIMBUS 7 ANTARCTIC OZONE MEASUREMENTS; MEAN TOTAL
OZONE IN OCTOBER
1979
1980
1981
1982
1983
1984
1985
Six-year sequence of October monthly means of total ozone. South
polar projections, with the pole indicated by a cross and 30"S
latitude by a dashed circle. The Greenwich meridian is towards the
top of each panel. Contours are every 30 DC. The shaded regions
indicate monthly mean total ozone amounts of <240 and >390 DC.
Source: Stolarski et al., 1986.
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2-26
melanoma incidence rates increase toward the equator, as UV-B exposure also
increases; (4) skin pigmentation provides a protective barrier that reduces
the incidence of non-melanoma skin tumors; (5) the risk of non-melanoma skin
tumors is highest among genetically-predisposed individuals; and (6) a
predisposition to develop non-melanoma skin tumors exists among light-skinned
individuals who are susceptible to sunburn and who have red/blond hair,
blue/green eyes, and a Celtic heritage (EPA, 1987).
Researchers have correlated UV measurements with non-melanoma incidence
data to develop models that predict the increases in incidence due to UV-B
increases in the United States. Results from six studies show that an
increase in UV-B of 1 percent would lead to an increase in non-melanoma
incidence of 1.8 to 2.85 percent. This range of estimates reflects
uncertainty over dose estimates and the weighing scheme used to account for
variations in damage caused by different wavelengths (EPA, 1987).
Melanoma skin cancer is a serious, life-threatening disease that affects
a large number of people in the United States. In 1985 there were an
estimated 25,000 cases and 5,000 deaths from melanoma in the U.S. In the
absence of changes in UV-B due to ozone depletion, the lifetime risk of
melanoma in the U.S. is expected to be about 1 in 250. While uncertainties
exist, a large array of evidence supports the conclusion that UV-B radiation
is one of the causes of melanoma (EPA, 1987).
The relationship between melanoma and UV-B is less certain than for non-
melanoma for the following reasons: (1) there currently is no animal model in
which exposure to UV-B experimentally induces melanomas; (2) there is no
experimental in vitro model for malignant transformation of melanocytes; and
(3) no epidemiological studies of melanoma have been conducted in which
individual human UV-B exposures (and biologically effective doses of solar
radiation) have been adequately assessed (EPA, 1987).
Despite these limitations, several lines of evidence support the
conclusion that melanoma is linked to UV-B radiation: (1) whites, whose skin
contain less protective melanin, have higher melanoma rates than blacks; (2)
light-skinned whites, including those who are unable to tan or who tan poorly,
have a higher incidence of melanoma than darker-skinned whites; (3) sun
exposure leading to sunburn apparently induces melanocytic nevi, which
researchers have associated with a greater risk of developing melanoma; (4)
sunlight also induces freckling, another risk factor for melanoma; (5)
incidence has been increasing in cohorts in a manner consistent with changes
in patterns of sun exposure; (6) higher incidences appear in immigrants who
move to sunnier climates; (7) evidence strongly links melanomas to childhood
sunburns; and (8) melanoma incidence increases with lower latitude, as UV-B
also increases .(EPA, 1987).
To evaluate the relationship between melanoma and UV-B, quantitative
estimates were developed in EPA's recently published risk assessment. Based
on a range of estimates for the major scientific uncertainties, the risk
assessment concluded that a 1 percent ozone depletion in the U.S. would lead
to a 1 to 2 percent increase in melanoma incidence and a 0.8 to 1.5 percent
increase in melanoma mortality (EPA, 1987).
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2-27
3. Other Hunan Health Effects: Tnmnm*. Suppression and Cataracts
Experimental studies have found the UV-B exposure leads to systemic
suppression of immune response (EPA, 1987). Reductions in immune function due
to stratospheric ozone depletion are likely to have a deleterious effect with
regard to many human diseases. Preliminary studies indicate that UV-B
radiation may prevent an effective immune response to micro-organisms that
infect the skin, thereby predisposing to reinfection or chronic infection.
Two human diseases that may be influenced by UV-B induced Immune suppression
are herpes virus infections and leishmaniasis, a disfiguring tropical disease.
Though potentially substantial, the link between UV-B and other diseases has
not been fully explored, and the effects in this area have not been quantified
for the purposes of this assessment.
UV-B has been found to play an important role in the formation of
cataracts. Supporting evidence includes UV-induced cataracts in laboratory
animals and epidemiological studies linking UV-B exposure (via latitude) to
cataract prevalence (EPA, 1987).
4. Plants
Limited studies have analyzed the effects of increased UV-B radiation on
plants. Studies generally show adverse impacts; however, because of
difficulties in experimental design, the large number of species involved, and
complex interactions that occur both in agricultural and natural ecosystems,
detailed quantitative estimates of effects are not currently possible (EPA,
1987).
Of plant cultivars tested in the laboratory, approximately 70 percent
were determined to be sensitive to UV-B. These experiments, however, do not
properly replicate field conditions, in which photorepair mechanisms appear to
be more effective.
The only long-term controlled field study of a crop involves soybeans
(Teramura, 1986). This study found that enhanced levels of UV-B radiation
simulating a 16 percent and 25 percent ozone reduction caused reductions in
crop yield of up to 25 percent in a particular cultivar. Substantially
smaller reductions in yield were exhibited in those years when the crop was
subject to drought, another perturbation.
Other aspects of UV-B effects on plants need further study. No research
has been conducted on six of the ten major terrestrial ecosystems and two-1
thirds of the plant growth forms. In addition to studying effects of plant
yield, researchers need to evaluate possible shifts in plant competition and
community composition, and interactions with other limiting growth factors
such as pathogens and drought.
5. Aquatics
Effects of UV-B radiation on aquatic ecosystems are also subject to
uncertainty, primarily due to the difficulty of measuring UV-B penetration and
-------
2-28
organism response. Studies have been conducted, however, that show that
zooplankton appear sensitive to UV-B radiation. If they are sensitive to
small increases in UV-B, they are likely to experience damage, as studies
indicate that they possess no sensory mechanism for detecting and thus
avoiding UV-B exposure (Worrest, 1982).
Other aquatic resources sensitive to UV-B include the larval stages of
fish and crustaceans. In one case study, a mathematical model predicted that
a 9 percent ozone reduction would lead to an 8 percent loss in larval anchovy
population (Hunter, Kaupp, and Taylor, 1982).
The effects of UV-B on individual organisms appear to differ for each
species, and thus an important implication of UV-B increases would be changes
in community composition and the aquatic food chain. Given our limited
knowledge of the individual species, however, it is not currently possible to
quantify in detail these effects (EPA, 1987).
6. UV-B Effects of Outdoor Materials and Ground-Level Pollution
Initial studies suggest that increases in UV-B radiation due to
stratospheric ozone depletion would accelerate the degradation of outdoor
materials and the formation of ground level pollution.
Several polymers are used in important commercial ortdoor applications
such as siding and window glazing. Laboratory and field experiments have
demonstrated that their current useful lifetime is shortened by exposure to
ambient levels of UV-B radiation. Absorbtion of UV-B by polymers causes
photo-induced reactions and alters important mechanical, physical and optical
properties of the polymers. Examples of UV-B damage include yellowing and
brittleness.
To protect polymers, producers add UV stabilizers to their products. A
case study found that the cost of adding extra stabilizers to compensate for
increased UV-B exposure due to ozone depletion (a 26 percent depletion by
2075) would lead to a cumulative cost of $4.7 billion in the U.S. (Horst et
al., 1986)
Initial studies have also evaluated the effects of UV-B on photochemical
reactions in the atmosphere. Case studies have found that increased UV-B
radiation would cause ground-based ozone to form earlier in the day, thus
exposing a greater population to its harmful effects. In addition, one study
indicates that large increases in hydrogen peroxide, an important acid rain
precursor, would result from increased UV-B (EPA, 1987).
7. Effects of Global Climate Change
Stratospheric modification may influence global climate in several ways.
First, many of the compounds that influence ozone are greenhouse gases and
will affect climate directly. Secondly, changes in the vertical distribution
of ozone would perturb the earth's radiative balance. Thirdly, increases in
stratospheric water vapor due to increases in methane concentrations would
directly affect climate. Exhibit 2-20 shows the increase in global
-------
2-29
equilibrium temperature expected by 2030 from projected emissions of these
trace gases. The direct radiative forcing from CFC concentrations accounts
for 23 percent of the expected warming (Ramanthan et al., 1985).
The key effects of projected climate change include increased in global
temperature and changes in key hydrological conditions such as precipitation
patterns.
Increased global temperature would accelerate the current rate of sea
level rise by expanding ocean water, melting alpine glaciers, and eventually
increasing the rate at which polar ice sheets melt or discharge ice into the
oceans. A substantial rise in sea level would permanently inundate wetlands
and lowlands, accelerate coastal erosion, exacerbate coastal flooding, and
increase the salinity of estuaries and aquifers.
Climate change would also have significant effects on agriculture,
forestry, water resources, human health, biodiversity and natural ecosystems.
Although no quantitative estimates of impacts from climate change are examined
in this study, these effects could be substantial.
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2-30
EXHIBIT 2-20
CUMULATIVE SURFACE TEMPERATURE CHANGE (K)
F»TV VCAM FHOM ISM UVfLSI
J»
I I I I I I I I I I
— J
1.
0.1 —
I I I I I I I I I I I
1 5
— IS
— 2
1
O
5
^
^
«
4
1.S
Cumulative equilibrium surface temperature warming due to increased of CO2
other trace gases. Surface temperature change is based on a 1-D model
including some climate feedbacks, with estimated feedback factor f - 1.5;
AT0, can be obtained by dividing the indicated surface temperature changes by
that value of f.
Source: NASA, 1986, Figure 38.
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2-31
REFERENCES
Angell, J.K. (1987), "Seasonal Differences in the Trend of Total Ozone .and
Contributions from Tropospheric and Stratospheric Layers," Monthly Weather
Review. 115, pp. 753-762.
Blake, D.R., E.W. Mayer, S.C. Tyler, Y. Makide, D.C. Montague, and S.S.
Rowland (1982), "Global Increases in Atmospheric Methane Concentrations
Between 1978 and 1980," Geophysical Research Letter. 9, pp. 243-248.
Connell, Peter S. and Donald J. Wuebbles (1986), Ozone Perturbations In the
LLNL One Dimensional Model - Calculated Effects of Projected Trends in CFCs.
CH/, ^ C02. NoO and Halons Over 90 years. Lawrence Livermore National
Laboratory, Livermore, CA.
Horst, R. , K. Brown, R. Black, and M. Kiankis (1986), The Economic Impact of
Increased UV-B Radiation on Polymer Materials: A Case Study of Rigid PVC.
Mathtech, Princeton, NJ.
Keeling, D.C., and GMCC/NOAA (n.d.), Monthly Concentrations of Carbon Dioxide
at Mauna Loa. Hawaii, unpublished.
Kerr, R.A. (1987), "Has Stratospheric Ozone Started to Disappear," Science.
237, pp. 131-132.
Khalil, M.A.K., and R.A. Rasmussen (1985), "The Trend of
Bromochlorodifluoromethane (CBrClF2) and the Concentrations of other Bromine
Containing Gases at the South Pole," Antarctic Journal of the United States:
1985 Review.
National Academy of Sciences (NAS) (1976), Halocarbons: Effects on
Stratospheric Ozone. National Academy Press, Washington, D.C.
National Academy of Sciences (NAS) (1984), Causes and Effects of Changes in
Stratospheric Ozone. National Academy Press, Washington, D.C.
NASA (1986), Present State of Knowledge of the Upper Atmosphere: An
Assessment Report. Processes that Control Ozone and Other Climatically
Important Trace Gases. NASA Reference Publication 1162, NASA, Washington, D.C.
Pearman, G.I., D. Etheridge, F. deSilva,' and P.J. Fraser (1986), "Evidence of
Changing Concentrations of Atmospheric C02, ^0, and CH4 from Air .Bubbles in
Antarctic Ice," Nature. 320, pp. 248-250.
Ramanathan, V., R.J. Cicerone, H.B. Singh, and J.T. Kiehl (1985), "Trace Gas
Trends and their Potential Role in Climate Change," Journal of Geophysical
Research. 90(D3), pp. 5547-5566.
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Rasmussen, R.A., and M.A.K. Khalil (1982), "Atmospheric Fluorocarbons and
Methyl Chloroform at the South Pole," Antarctic Journal of the United States:
1982 Review, pp. 204-205.
Rasmussen, R.A., and M.A.K. Khalil (1986), "Atmospheric Trace Gases: Trends
and Distributions over the Last Decade," Science. 232, pp. 1623-1624.
Rinsland, C.P., J.S. Levine, and T. Miles (1985), "Concentrations of Methane
in the Troposphere Deduced from 1951 Solar Spectra," Nature. 318, pp. 245-249.
Scotto, Fears, and Fraumeni (1981), Incidence of Nonmelanoma Skin Cancer in
the United States. U.S. Department of Health and Human Services, 82-2433,
Bethesda, MD.
Stolarski, R.S., A.J. Krueger, M.R. Schoebert, R.D. McPeters, P.A. Newman, and
J.C. Alpert (1986), "Nimbus 7 Satellite Measurements of the Springtime
Antarctic Ozone Decrease," Nature. 322, pp. 808-810.
Stordal, F., and I.S.A. Isaksen (1986), "Ozone Perturbations Due to Increases
in N20, CH^, and Chlorocarbons: Two-Dimensional Time-Dependent Calculations,"
in J.G. titus, (ed.), Effects of Changes in Stratospheric Ozone and Global
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Teramura, A.H. (1986), "The Potential Consequences of Ozone Depletion Upon
Global Agriculture," in J.G. Titus, (ed.), Effects of Changes in Stratospheric
Ozone and Global Climate. Vol""e 2. Stratospheric Ozone, U.S. EPA and UNEP,
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Ultraviolet Radiation in Marine Ecosystems. Plenum, NY.
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CHAPTER 3
DESCRIPTION OF ALTERNATIVES
ABSTRACT
On September 16, 1987, the United States, 23 other nations and the European
Economic Community signed the Montreal Protocol on Substances that Deplete the
Ozone Layer, which calls for global limits on the consumption and production of
chlorofluorocarbons and halons. This EIS evaluates the Protocol and a range of
alternatives including:
o No U.S. ratification (or entry into force) of the Montreal Protocol
and no unilateral U.S. action.
o U.S. ratification (and entry into force) of the Montreal Protocol, and
its domestic implementation.
o U.S. ratification (and entry into force) of the Montreal Protocol, and
domestic regulations that are more stringent than its provisions
(i.e., U.S. reductions of 80 percent).
o U.S. ratification (and entry into force) of a Protocol but with
reductions less stringent than called for in the Montreal Protocol
(i.e., freeze only or 20 percent reduction.)
o U.S. ratification (and entry into force) of a Protocol, but with
international reductions more stringent than called for in the
Montreal Protocol (i.e., 85 percent reductions).
o No U.S. ratification (or entry into force) of the Montreal Protocol
but unilateral action by the U.S.
The first section of this chapter details the provisions of the Montreal
Protocol, including chemical coverage, stringency, and trade provisions. The
next section further defines the control levels that are analyzed in this EIS.
The final section describes a series of sensitivity cases that vary key
underlying assumptions in the analysis, such as levels of international
participation in controls.
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3-2
PROVISIONS OF THE MONTREAL PROTOCOL
Chfiii *?a1 Coverage
In Che Montreal Protocol, two sets of chemical compounds are considered
separately. "Group 1" chemicals include the fully halogenated CFCs: CFC-11,
-12, -113, -114 and -115. "Group 2" chemicals include the Halons: Halon 1211,
1301, and 2402.
Allowable consumption and production of these compounds is interchangeable
within each group based on ozone-depletion weights (see Exhibit 3-1 below).
Stringency
The Montreal Protocol requires phased-in reductions in weighted consumption
and production of Group 1 CFCs and a freeze on weighted consumption and
production of Group 2 halons.
The timing of some of the protocol provisions depends upon the date at
which it enters into force. This will occur on January 1, 1989, if 11 nations
and/or regional economic integration organizations (e.g., the European Economic
Community) which together represent two-thirds of global consumption of the
controlled substances become parties to the protocol by that date or 90 days
after those conditions are met, whichever is later.
Beginning the first day of the seventh month after the protocol enters into
force, annual weighted production and consumption of Group 1 compounds will be
frozen for each nation based on its weighted 1986 consumption and production.
Beginning July 1, 1993, annual weighted production and consumption of Group
1 chemicals must be reduced to 80 percent of 1986 baseline levels. Beginning
July 1, 1998, annual weighted production and consumption of Group 1 compounds
will be reduced to 50 percent of each nation's 1986 levels.
Thirty-seven months after entry into force, each nation's annual production
and consumption of the Group 2 halons will be frozen at its 1986 levels.
The Montreal Protocol allows limited increases in production of 10 percent,
or 15 percent after July 1, 1998, above the restricted levels for the purposes
of industrial rationalization or exports to developing nations as described
below.
Additional Provisions
a. Developing Nations. To encourage long-term participation by developing
nations, the protocol provides a short-term exemption from its restrictions.
Nations whose weighted consumption of controlled substances is less than 0.3
kilograms per capita are permitted to increase their use up to that level for a
period of ten years, and then must begin their reduction schedule. To assure
supply to developing nations, developed nations may produce at levels slightly
above their own allowed domestic consumption levels.
b. Industrial Rationalization. Parties are also permitted to exceed their
allowable level of production for purposes of industrial rationalization which
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3-3
is defined in the Protocol as "the transfer of all or a portion of the
calculated level of production of one party to another for the purpose of
achieving economic efficiencies or responding to anticipated shortfalls in
supply as a result of plant closures.'
n
c. Production Facilities Under Construction. Under specified conditions,
nations that had production facilities under construction, or contracted for,
are permitted to add production from those facilities to their 1986 baseline
levels, provided that their total weighted consumption would not exceed 0.5
kilograms per capita. Under this provision, the Soviet Union will be permitted
to complete construction of two CFC plants called for in its latest 5-year
economic plan.
Trade Provisions
Trade among protocol parties is not restricted. However, imports from non-
parties of bulk CFCs are banned one year after entry into force. The protocol
calls for developing a list of products containing CFCs (e.g., air
conditioners) of which imports from non-parties would be banned in the fourth
year after entry into force. Within five years after entry into force, the
parties are to determine the feasibility of import restrictions on products
manufactured with, but no longer containing, CFCs (e.g., computer chips that
were cleaned with CFC-113).
Periodic Assessnents
The protocol calls for periodic reassessments of the control measures based
on advances in scientific, environmental, technical, and economic information.
The first such reassessment is scheduled for .1990, with expert panels to be
convened in 1989.
EIS AT.TgRHATlVKS
The alternatives evaluated in this EIS are chosen to assist in the U.S.
decision on adherence to the Montreal Protocol. The primary alternatives are:
1. No Controls: No U.S. ratification (or entry into force) of the
Montreal Protocol and no unilateral U.S. action.
2. Protocol: U.S. ratification (and entry into force) of the Montreal
Protocol, and its domestic implementation.
3. Protocol/U.S'. 80%: U.S. ratification (and entry into force) of the
Montreal Protocol and domestic regulations that require a unilateral
80 percent reduction in the use of CFCs by 2004 (which is more
stringent than the Protocol requirements).
4. Unilateral U.S.: No U.S. ratification (or entry into force) of the
Montreal Protocol but unilateral action by the U.S. that corresponds
to the protocol provisions.
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3-4
5. Freeze: U.S. ratification (and entry into force) of an international
agreement that requires a freeze in the consumption and production of
CFCs at 1986 levels (this represents the first stage of the protocol
requirements).
6. 20% Reduction: U.S. ratification (and entry into force) of an
international agreement that requires a 20 percent reduction in the
consumption and production of CFCs relative to 1986 levels (this
represents the first two stages of the protocol requirements).
7. 85% Reduction: U.S. ratification (and entry into force) of an
international agreement that requires nations to make an 85 percent
reduction in the consumption and production of CFCs relative to 1986
levels and a freeze on halons (this is more stringent than the
protocol requirements).
In the analysis that follows these EIS alternatives are referred to using
the underlined notation shown above.
U.S. ratification will play a large role in determining whether the
Montreal Protocol enters into force. Non-ratification of the Montreal Protocol
by the U.S. would probably preclude entry into force. Entry into force
requires ratification by nations representing two-thirds of global weighted
consumption of controlled substances, and the U.S. accounts for approximately
one-third of the global total. Moreover, U.S. leadership was important in the
protocol negotiations.
The Montreal Protocol has already been signed, and is likely to be
ratified, by nations representing sufficient global consumption of controlled
substances that, with ratification by the U.S., future entry into force is
likely.
The analyses of ozone depletion and human health and environmental effects
for each of the EIS alternatives rely on a series of assumptions regarding
domestic and international compound usage, and other factors. Several of the
assumptions are identified in the following description of sensitivity tests.
Others are described in Chapter 4 (assumptions for modeling ozone depletion and
human health effects) and in Chapter 5 (assumptions for estimating costs).
DESCRIPTION OF ADDITIONAL SENSITIVITY TESTS -- OTHER ALTERNATIVES CONSIDERED
Projections of future stratospheric modification are sensitive to changes
in the quantities of trace gases that reach the stratosphere. The
effectiveness of alternative strategies in protecting ozone will thus differ
depending on the consequent trends and possible reductions in trace gas
emissions. Critical elements in assessing these reductions include chemical
coverage, stringency, and international participation.
Chemical Coverage Options
Several chemical compounds are potential ozone depleters: CFC-11, CFC-12,
HCFC-22, CFG-113, CFC-114, CFC-115, carbon tetrachloride, methyl chloroform,
Halon 1211, Halon 1301, and Halon 2402. These compounds contain chlorine and
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3-5
bromine, which are capable of catalytically depleting ozone in the
stratosphere. Furthermore, most have very long atmospheric lifetimes, allowing
them to be transported to the stratosphere. The relative ozone depleting
potential of each compound is generally a function of its chlorine and bromine
content and atmospheric lifetime. Exhibit 3-1 shows the chemical formula,
atmospheric lifetime, and relative ozone depletion potential per kilogram of
each compound.
Exhibit 3-1 shows that two of the chlorinated compounds, HCFC-22 and methyl
chloroform, have relatively short atmospheric lifetimes and low ozone depleting
potentials. Because HCFC-22 and methyl chloroform are substantially less
harmful to ozone, they are excluded from coverage. Because of their short
atmospheric lifetimes, the future atmospheric concentrations of these chemicals
can be more quickly reduced by emission limits if that is deemed necessary in
the future.
In contrast, carbon tetrachloride is a relatively strong potential ozone
depleter, having four chlorine atoms per molecxile and a long atmospheric
lifetime. It is excluded from coverage; however, because most of the carbon
tetrachloride produced is consumed as a feedstock in manufacturing CFCs and
relatively little is emitted into the atmosphere. Remaining uses as a grain
fumigant and as a solvent are severely restricted under other Federal
regulations.
The fully-halogenated CFCs and halons are considered separately in analyses
of chemical coverage because of their differing ozone-depleting weights and use
characteristics -- CFCs are emitted relatively promptly while halons are banked
and most emission- occur during discrete events such as system testing, fires,
or training.
In EIS alternative 2, Protocol. CFCs are reduced 50 percent and halons are
frozen. As a sensitivity case, the controls on the halons are omitted.
Stringency
The total reductions achieved in emissions of fully-halogenated CFCs and
halons will depend on the stringency with which the covered chemicals are
controlled. In evaluating the effect of reductions on projected ozone
depletion, a range of stringency alternatives must be evaluated. The
foreseeable spectrum of stringency alternatives ranges from no controls (based
on U.S. non-ratification of the Montreal Protocol), to international
implementation of an international agreement more stringent than required by
the Montreal Protocol.
The EIS alternatives 5, 6, and 7 described above cover a broad range of
stringency requirements, from a freeze to an 85 percent reduction. No
additional stringency sensitivities of this type are performed. However, four
additional cases examine alternative stringency requirements for the Soviet
Union (USSR) and for developing nations.
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3-6
EXHIBIT 3-1
CHEMICAL FORMD1A, ATMOSPHERIC LIFETIME, AND
OZONE-DEPLETING POTENTIAL OF POTENTIAL OZONE DEPLETERS^/
Atmospheric Ozone Depletion
Lifetime Potential
Compound Formula (years) (mass basis)
CFC-11 CC13F 75 1.0
CFC-12 CC12F2 111 1.0
HCFC-22- CHC1F2 20 0.05
CFC-113 C2C13F3 90 0.8
CFC-114 C2C12F4 185 1.0
CFC-115 C2C1F5 380 0.6
Halon 1211 CBrClF2 25 3.0
Halon 1301 CF3Br 110 10.0
Halon 2402 C2F4fir2 not reported 6.0
Methyl Chloroform CH3CC13 6.5 0.1
Carbon Tetrachloride CC14 50 1.06
a/ Lifetime estimates are based on WHO (1986), and are summarized in the EPA
Risk Assessment (EPA, 1987a). Ozone-depletion potentials are reported in the
protocol for the fully-halogenated CFCs and for Halon 1211 and Halon 1301. The
ozone-depletion potentials for HCFC-22, methyl chloroform, and carbon tetra-
chloride were reported by Connell (personal communication) based on results of
the Lawrence Livermore National Laboratory one-dimensional atmospheric model.
The ozone-depletion potential for Halon 2402 is not part of the Protocol text,
but was reported at negotiations for the Montreal Protocol and, along with the
depletion weights for the other halons will be subject to future revisions.
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3-7
As described above, the protocol allows the USSR limited expansion in
production through 1990. Two sensitivity cases examine the implications of
requiring the USSR to.reduce their use relative to their 1986 levels. For one
sensitivity case, the USSR is assumed to participate in the controls. Another
sensitivity case assumes that the USSR does not participate in the controls
because it is not allowed to expand production.
Also, the protocol allows developing nations to increase use over a period
of ten years. Two sensitivity cases examine the implications of requiring the
developing nations to follow the same timetable of reductions as developed
nations. In the first case, developing nations representing 65 percent of
compound use in these nations are assumed to participate in controls. The
second case evaluates ozone depletion if only 40 percent of compound use in
developing nations is subject to controls because fewer developing nations
participate in this more stringent requirement.
International Participation
Stratospheric ozone depletion is a global issue which depends on the
worldwide production and consumption of CFCs and halons. In evaluating the
effectiveness of regulatory alternatives, assumptions must be made as to the
extent of worldwide participation in the controls.
It is unlikely that all nations of the world will participate in-the
Montreal Protocol. For purposes of assessing the EIS alternatives, assumptions
regarding potential international participation are required.
Exhibit 3-2 lists the nations that have already signed the Protocol. As
shown in the exhibit, 24 nations plus the EEC have signed. Virtually all
industrialized nations have indicated an intention to sign.
It is estimated that the nations who have signed the Montreal Protocol or
have been involved in its international negotiation account for a large
majority of global CFC and halon production. However, a significant portion of
this production (e.g., one-third from the EEC) is exported, some portion
potentially to nations that have not been involved to date. Also, many CFC-
related products are exported. Therefore, the effective global participation
in the Montreal Protocol may be expected to be less than 100 percent, the
extent to which will likely depend on the effectiveness of its trade
provisions.
In the EIS alternatives 1 and 4 (No Controls and Unilateral U.S.) it is
assumed that without U.S. ratification the Montreal Protocol does not enter
into force, and other nations do not restrict CFC or halon use. In the other
EIS alternatives, it is assumed that: (1) in addition to the U.S., developed
nations representing 94 percent of consumption in developed nations outside the
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3-8
EXHIBIT 3-2
SIGNATORIES TO THE MONTREAL PROTOCOL
Belgium
Canada
Denmark
Egypt
European Economic Community
Finland
France
Germany
Ghana
Italy
Japan
Kenya
Mexico
Netherlands
New Zealand
Norway
Panama
Portugal
Senegal
Sweden
Switzerland
Togo
United Kingdom
United States
Venezuela
Source: U.S. EPA
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3-9
U.S. participate; and (2) developing nations representing 65 percent of
developing nations' consumption.
Due to the considerable uncertainty regarding future participation, low and
high sensitivity cases are examined. In the low case, it is assumed that
nations representing only 75 percent of consumption in developed nations
(outside the U.S.) and 40 percent of consumption in developing nations join the
protocol. In the high case, it is assumed that 100 percent of developed
nations and 100 percent of developing nations join the protocol.
Trace Gas Concentrations
As described above in Chapter 2, the concentrations of C(>2 CH^ and ^0
also influence total column ozone levels. In all seven EIS alternatives the
following assumptions are made about the growth in these trace gas
concentrations: CH^ 0.017 ppm/yr; CC^: NAS 50th percentile estimates (about
0.7 percent per year); and ^0: 0.2 percent per year. Low and high
sensitivity cases are examined for these gases as follows:
o Low trace gas sensitivity:
-- CH4- 0.01275 ppm/yr (75 percent of the base assumption)
-- 0)2: NAS 25th percentile estimate
-- N20: 0.15 percent per year.
o High trace gas sensitivity:
-- CH^. 1 percent compound growth
-- C(>2: NAS 75th percentile estimate
-- ^0: 0.25 percent per year.
These sensitivity cases reflect uncertainties in our understanding of these
gases. In addition, however, these trace gases all contribute to the
greenhouse effect. Therefore, it is possible that in the future governments
may agree to limit the growth in the concentrations of these gases. As an
additional sensitivity, it is assumed that governments limit these gases
sufficiently to limit equilibrium greenhouse-gas warming to 38C by 2075.^
1 As described in EPA (1987b), it is assumed that the non-participants'
use of the controlled compounds does not grow as rapidly as would be expected
in the absence of the controls by others. The reduction in growth is due to
the development of non-CFC and non-halon dependent technologies by the
participants. These technologies may spread to the non-participants, thereby
reducing their CFC and halon use.
f\
*• The three gases that are limited in this scenario are CH^, C02, and
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3-10
Rates of Compound Growth
Based on analyses by EPA and others (see Chapter 4 below), it is assumed
that the use of CFCs and the other compounds will grow between zero percent and
five percent per year in the future (EPA, 1987a). The EIS alternatives 1
through 7 are evaluated below using a growth rate of about 2.7 percent per year
through 2050-, with no growth thereafter. As sensitivities, average annual
growth rates of 1.3 percent (low case) and 4 percent (high case) are assumed
through 2050, with no growth thereafter.
Exhibit 3-3 lists the sensitivities examined.
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3-11
EXHIBIT 3-3
SENSITIVITY CASES EXAMINED
Chemical Coverage
No Halons Controls: Halon freeze omitted from Protocol case.
Stringency
USSR @ 1986 Base levels: USSR not permitted to increase production through
1990.
USSR Nonparticipation: USSR not permitted to increase production through
1990 -- and USSR does not participate.
Developing @ 1986 Base levels: Developing nations not permitted to
increase use over a ten year period.
Developing @ 1986 levels: 40% Participation: Developing nations not
permitted to increase use over a ten year period - - low participation among
developing countries.
Participation .
Low Participation: 75 percent among non-U.S. developed nations, 40 percent
among developing nations.
High Participation: 100 percent global participation.
Trace Gas Growth
Low Trace Gas: Lower rates for CH^, C02, and
High Trace Gas: Higher rates for 014, C02, and
Warming Limited: Trace gas growth constrained to limit global warming to
3°C by 2075.
Rates of Compound Growth
Low Compound Growth: 1.3 percent per year through 2050, no growth
thereafter.
High Compound Growth: 4 percent per year through 2050, no growth
thereafter.
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3-12
REFERENCES
EPA (1987a), Assessing the Risks of Trace Gases that Can Modify the
Stratosphere. U.S. Environmental Protection Agency, Washington, D.C.
EPA (1987b), Regulatory Impact Analysis: Protection of Stratospheric Ozone.
U.S. Environmental Protection Agency, Washington, D.C.
WHO (1986), Atmospheric Ozone 1985. Assessment of our Understanding of the
Processes Controlling its Present Distribution and Change. World Meteorological
Organization Global Ozone Research and Monitoring Project -- Report No. 16,
Geneva, Switzerland.
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CHAPTER 4
HEALTH AMD ENVIRONMENTAL CONSEQUENCES OF ALTERNATIVES
ABSTRACT
Future growth in use and emissions of chlorofluorocarbons (CFCs) and
halons could lead to significant depletion of stratospheric ozone, resulting
in increases in harmful ultraviolet radiation (UV-B). Increased exposure to
UV-B radiation could lead to increases in skin cancer incidence and mortality,
increased cataract prevalence, suppression of the human immune system, damage
to crops and aquatic ecosystems, increased formation of ground level ozone
(smog), and accelerated degradation of outdoor materials. Entry into force of
the Montreal Protocol on Substances that Deplete the Ozone Layer would reduce
future use of CFCs and halons, and thus reduce the incidence and severity of
projected health and environmental damages from depletion of stratospheric
ozone.
This chapter presents estimates of health and environmental impacts of
ozone modification. The first section summarizes the methods and data used to
estimate these impacts. The second section then presents estimates of these
impacts. A final section shows ozone depletion estimated for a set of
sensitivity cases that vary key assumptions used in the analysis.
MODELLING THE EFFECTS OF ALTERNATIVES
To assess the effects of alternative strategies to limit stratospheric
ozone depletion, EPA has developed an integrated model of current and future
CFC and halon use and emissions, atmospheric response, and the effects of UV-B
increases and global climate change on human health, welfare, and the
environment. The model is documented in Chapter 17 of EPA's recently
completed risk assessment (EPA, 1987a). The executive summary of this risk
assessment is attached to this EIS as Appendix B to this document. A
description of the model's major components is presented below.
Use and Emissions of CFCs and Halons
The model tracks current and projected use of five fully-halogenated
CFCs: CFC-11, CFC-12, CFC-113, CFC-114, CFC-115; and two brominated compounds:
Halon 1211, and Halon 1301. Halon 2402, which is controlled in the Montreal
Protocol, is not included in the integrated model due to a lack of data.
For purposes of specifying baseline use of these compounds, the model
divides the world into six regions:
o United States
o USSR and Eastern Bloc
o Other Developed Countries (e.g., Western European countries,
Canada, Japan, Australia, New Zealand)
o Peoples' Republic of China and India
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4-2
o Developing countries with.1985 compound use of 0.1 to 0.2
kilograms per capita (Group I Developing Countries) (e.g.,
Argentina, Mexico, South Korea, Turkey, Malaysia)
o Other Developing Countries (Group II Developing Countries) (e.g.,
African countries).
Exhibit 4-1 displays estimates of the 1985 use of these compounds across these
regions taken from EPA (1987b). Although the regional distribution outside
the U.S. is somewhat uncertain, the global totals are considered reliable.
Use of each compound is allocated among ten major end-use categories:
o Aerosol propellant
o Flexible Foam
o Rigid Polyurethane Foam
o Rigid Nonurethane Foam
o Fast release refrigeration
o Medium release refrigeration
o Slow release refrigeration
o Solvent
o Fire extinguishing
o Miscellaneous.
EPA (1987b) presents estimates of the distribution of use across these
categories, and estimates of rates of release from each.
In 1986, both the U.S. Environmental Protection Agency and the United
Nations Environment Programme convened domestic and international workshops
that focused on the future demand for CFCs and halons. Researchers presented
evidence that in the near term, market conditions would support growth in
specific CFC and halon uses, and that in the long term, general CFC and halon
growth would continue based on the strong historical correlation between CFC
use and economic growth (Quinn et al., 1986; and Gibbs, 1986).
Based on the research presented at these workshops, in its Regulatory
impact Analysis, EPA developed baseline CFC and halon projections (EPA,
1987b). The baseline case for 1985 to 2050 assumes world growth in CFC use of
slightly higher than 2.5 percent per year (relative to the scenarios presented
in EPA (1987a). This estimate is adjusted to reflect the higher than
previously expected Soviet growth resulting from future construction of two
CFC production facilities and more recent information that suggests stronger
growth in developing nations). After the year 2050, projected use of both
CFCs and halons is held constant to account for the growing uncertainty
associated with long-term projections. Exhibit 4-2 summarizes these baseline
projections.
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4-3
EXHIBIT 4-1
COMPOUND USE IN 1985 BY REGION
(millions of kilograms)
Compound
CFC-ll
CFC-12
CPC-113
CFC-114
CFC-11S
Halon 1211
Halon 1301
United States
79.7*'
136.9*'
68.5*'
4.0*'
4.5*'
2.8*
3.3*
USSR and .
East Blocs/
42.8
89.2
9.0
2.0
0.8
0.9
0.7
Other
Developed2'
172.9
151.0
88.8
5.1
2.2
2.3
1.9
China and
India-'
4.4
12.2
1.1
0.2
0.1
0.1
0.1
Developing .
Nations Group I-
21.0
33.7
3.8
0.8
0.4
0.4
0.3
Developing .
Nations Group II-
47.5
32.0
5.8 •
1.3
0.5
0.6
0.5
Total
368.3^
455.0*'
177.0*
13.5*'
8.3*
7.0^
7.0*
a/ ITC (1987).
b/ Bamnitt (1986).
£/ Industry estimates of U.S. and global CFC-114 an CFC-115 use supplied to EPA.
d/ lEc (1987).
e/ Share of use in the non-U.S. regions is estimated based on published estimates. Exhibit 4-2 below.
f/ Global estimates derived from CMA (1986) and UNEP (1986).
-------
4-4
EXHIBIT 4-2
PROJECTED USE BY COMPOUND BY REGION
(thousands of metric tons)
CFC-II
CFC-12
CFC-113
CFC-II4
CFC-M5
HALON 1211
HALON 1 30 1
GLOBAL
UNITED STATES
USSR & EAST BLOC
OTHER DEVELOPED
CHINA ft INDIA
DEVELOP INC (CROUP I)
DEVELOPING (CROUP II)
GLOBAL
UNITED STATES
USSR I EAST BLOC
OTHER DEVELOPED
CHINA I INDIA
DEVELOPING (GROUP I)
DEVELOPING (GROUP II)
GLOBAL
UNITED STATES
USSR I EAST BLOC
OTHER DEVELOPED
CHINA 4 INDIA
DEVELOPING (CROUP I)
DEVELOPING (GROUP II)
GLOBAL
UNITED STATES
USSR 1 EAST BLOC
OTHER DEVELOPED
CHINA ft INDIA
DEVELOPING (GROUP I)
DEVELOPING (GROUP II)
GLOBAL
UNITED STATES
USSR ft EAST BLOC
OTHER DEVELOPED
CHINA I INDIA
DEVELOPING (CROUP 1)
DEVELOPING (GROUP II)
GLOBAL
UNITED STATES
USSR ft EAST BLOC
OTHER DEVELOPED
CHINA ft INDIA
DEVELOPING (CROUP I)
DEVELOPING (GROUP II)
GLOBAL
UNITED STATES
USSR ft EAST BLOC
OTHER DEVELOPED
CHINA ft INDIA
DEVELOPING (CROUP 1)
DEVELOPING (CROUP II)
1966
368.3 •
79.7 b
42.6 c
172.9 c
4.4 C
21.0 c
47.6 c
4SS.O •
136.9 b
89.2 c
151. 0 c
12.2 C
33.7 c
32.0 c
177.0 k
66. 5 k
9.0 •
88.8 1
1 . 1 •
3.6 •
5.8 •
13. SO o
4.00 o
2.00 p
5.13 p
0.25 p
0.84 p
1.28 p
6.50 o
4.50 o
0.84 p
2 Hi p
0. II p
0.35 p
0.54 p
7.00 r
2.75 r
0.89
2.30
0. II
0.38
0.57
7.00 r
3.50 r
0.74
1.89
0.09
0.31
0.47
1986
421 .7 d
91.3 •
49.0 B
198.0 f
5.1 1
24.0 ft
54.4 J
485.8 d
146.2 •
95.2 a
161.2 f
13.1 1
36.0 t\
34.1 J
183.6 n
71 . 1 n
9.4 n
92.2 n
1.2 n
3.9 n
6.0 n
13.84 q
4. 10 q
2.05 q
5.26 q
0.26 q
0.86 q
1.31 q
8.71 q
4.61 q
0.86 q
2.22 q
0. 1 1 q
0.36 q
0.55 q
9.69 r
2.87 r
1 .44
3.69
0.18
0.60
0.92
6.00 r
4.03 r
0.84 »
2.14 •
0.10 •'
0.35 •
0.53 »
19901
479. 1
100.8
66.7
218.5
7.5
29.2
56.6
567.2
161.4
129.5
177.9
19.1
43.8
35.5
217.5
82.3
14.7
106.8
2.0
5.2
6.3
15.91
4.53
2.79
5.81
0.37
I.OS
1 .36
9.88
5.09
1. 17
2.45
0. 16
0.44
0.57
14.31
4.15
2. 14
5.49
0.27
0.90
1.37
9.52
4.61
1.03
2.65
0. 13
0.43
0.66
2000 1
623.4
129.0
65.3
279.7
19.3
47.5
62.5
760.3
206.6
165.8
227.8
49.6
71.3
39.2
321.0
119.0
21.3
154..
8.3
10.8
7.4
20.98
5.79
3.57
7.44
0.97
1 .70
I.SO
12.91
6.52
1.50
3.13
0.41
0.72
0.63
24.68
6.40
3.85
9.88
0.48
1.62
2.46
8.21
3.59
0.97
2. SO
0.12
0.41
0.62
2050t
2142.6
443.4
293.3
961.4
66.5
163.3
214.8
2613. 1
710. 1
569.9
782.9
170.5
245.0
134.8
1103.2
409.0
73. 1
530.3
28.4
37. 1
25.3
72. t 1
19.91
12.27
25.56
3.34
5.86
5. 17
44.38
22.40
5. 17
10.76
1.41
2.47
2.18
104.71
24. 79
16.83
43.20
2. 10
7.06
10. 74
38.87
17.89
4.42
1 1 .34
O.SS
i .as
2.82
-------
4-5
EXHIBIT 4-2
PROJECTED USE BY COMPOUND BY REGION
(continued)
FOOTNOTES TO EXHIBIT 4-2
a Global estimate calculated from CMA (1986) and Hammitt (1986).
b U.S. International Trade Commission (1987).
c Estimate for region calculated using shares of global compound use
identified for 1986.
d Global estimate calculated from CMA (1986), Hanmitt (1986), and ITC
(1987).
e U.S. International Trade Commission (1987), preliminary estimate.
f EEC estimate calculated from U.S. industry estimate provided to U.S.
EPA; Sheffield (Canadian) estimate provided to U.S. EPA: Australia
estimate from UNEP (1986) Japanese estimate from Kurosawa and Imazeki
(1986); other use estimates based on Dupont (1987) use per capita
estimates provided to U.S. EPA.
g USSR and East Bloc estimate calculated from industry estimates
provided to U.S. EPA.
h OuPont (1987). Use estimated by multiplying estimated use per capita
by population.
i Estimated from Zhijia (1986).
j Global estimate minus documented use.
k Hanmitt (1986).
1 Araki (MITI) in U.S. state department cable; Buxton (1987) personal
correspondence.
m Regional estimates are same proportion of remaining use as average
proportion of CFC-11 and CFC-12 in 1986.
n All estimates 3.75 percent higher than 1985 levels, see EPA Q987a).
o U.S. industry estimates provided to EPA.
p Non-U.S. use is allocated in the same regional proportions as the
average of CFC-11 and CFC-12.
q 1986 estimates are 2.5 percent greater than 198S estimates, see EPA
(1987a).
r Revised version of lEc (1987).
s Non-U.S. use is allocated in the same regional proportions as the
average of CFC-11 and CFC-12.
-------
4-6
Other Trace Gases
Several other chlorinated compounds , including carbon tetrachloride
(0014), methyl chloroform (Cl^CC^) , and HCFC-22 are not controlled in the
Montreal Protocol, but are considered in the integrated model because their
future use and emissions will influence future depletion. The baseline trends
for these gases are discussed in EPA's Risk Assessment (EPA, 1987a) . Three
other trace gases have an important effect on ozone depletion:
o Carbon dioxide (CC>2)
o Methane (CH4)
o Nitrous oxide
Future stratospheric ozone levels appear to be especially sensitive to future
trends in methane concentrations. Methane and carbon dioxide act to offset
ozone depletion from CFCs and halons. Nitrous oxide could either increase or
decrease ozone levels depending on the relative concentrations of chlorine and
nitrogen in the stratosphere. Each of these gases contributes to the
projected global warming associated with the greenhouse effect. The sources,
sinks, and projected emissions and concentrations of these gases are discussed
in EPA (1987a). In this EIS , the middle case scenario of future
concentrations is adopted and sensitivity anal/ses are shown for alternative
assumptions.
For carbon dioxide, projected concentrations are taken from projections
prepared by Nordhaus and Yohe (1983) for the National Academy of Sciences, who
developed a probabilistic model that linked future economic and population
growth to energy use and emissions. In the 50th percentile scenario that is
used in this EIS, the average annual rate of growth in carbon dioxide
concentrations from 1975 to 2100 is approximately 0.7 percent per year. After
2100, concentrations are assumed to grow by 5.9 parts per million (ppm) per
year.
Integrated projections of methane are more difficult to prepare because of
current uncertainty about sources and sinks, and in this study it is assumed
that growth in concentrations continues at the historically observed linear
rate of 0.017 parts per million per year.
Future nitrous oxide concentrations are also extrapolated based on
historical growth of 0.2 percent per year.
Exhibit 4-3 shows the concentrations of carbon dioxide, methane, and
nitrous oxide used for the middle case.
Modelling Future Ozone Depletion
The current models that have been developed to explore the effects of
trace gases on the stratosphere are described in Chapter 2. In its integrated
assessment model, EPA uses a parameterization of the Lawrence Livermore
National Laboratory one -dimensional model that was found to produce ozone
-------
4-7
EXHIBIT 4-3
GROWTH OF TRACE GAS CONCENTRATIONS OVER TIME
(Middle Case)
Year
1985
2000
2025
2050
2075
2100
2165
Carbon Dioxide
(ppm)
350.2
366.0
422.0
508.0
625.0
772.0
1,154.2
Methane
(ppm)
1.8
2.0
2.4
2.9
3.3
3.7
4.8
Nitrous Oxide
(ppb)
303.1
312.3
328.3
345.1
362.8
381.4
434.3
Source: U.S. EPA (1987b).
-------
4-8
depletion estimates that are within the range of the estimates of the more
complex models, although slightly on the low side (i.e., underestimating ozone
depletion in some cases (UNEP, 1987)). Exhibit 4-4 compares the results of
the parameterized model and several 1-dimensional models and a. 2-dimensional
model for the same trace gas scenario.
Increases in TJV-B Radiation
Future depletion of stratospheric ozone would allow greater quantities of
ultraviolet radiation to reach the earth's surface. The relative increase
would be greatest at the shorter, more harmful wavelengths of UV-B, and each
one percent ozone depletion would lead to an increase of roughly two percent
in biologically-damaging UV-B (NAS, 1984). In the integrated model, estimates
of the ozone depletion-induced changes in UV-B are based on a model that
parameterizes satellite observations of UV and ozone levels (Serafino and
Frederick, 1986). As shown in Exhibit 4-5, the model predicts average UV
levels (for two different biological-damage weighting schemes) for three U.S.
regions.
Umrnaol anmrna Skin Cancer
The e idence linking UV-B radiation to nonmelanoma skin cancer is
summarized in Chapter 2. In the integrated model, changes in the incidence of
nonmelanoma skin cancer as a result of UV increases are calculated with the
following dose-response equation:
Fractional change in incidence - (fractional change in exposure + 1)^ - 1
where the fractional change in exposure is defined as the change in UV flux
reaching the earth's surface during a person's life and "b" is the dose-
response coefficient, often referred to as the "biological amplification
factor" (BAF). The BAF equals the percent change in incidence associated with
a 1 percent change in UV exposure.
In this analysis, the BAF is computed based on epidemiological studies
conducted by the National Cancer Institute (Scotto, 1986). Values of the BAF
are computed separately for basal cell and squamous cell skin cancers, and are
based on UV levels weighted by the relative effectiveness of each waveband in
damaging DNA (this is commonly referred to as the "DNA damage action
spectrum"). These coefficients are" presented in Exhibit 4-6.
Using these dose-response coefficients and the percent increase in DNA-
damage weighted UV-B radiation computed by the integrated model, the percent
increase in nonmelanoma skin cancer is computed. This percentage increase in
skin cancer is then multiplied by .the baseline incidence to compute the total
number of additional cases.
Although most cases of nonmelanoma skin cancer can successfully be
treated, a small fraction metastasize and result in death. Although the
mortality rate is somewhat uncertain due to poor data, current estimates are
-------
4-9
EXHIBIT 4-4
COMPARISON OF ATMOSPHERIC MODELS
AND PARAMETERIZED MODEL USED BY EPA
Ozone
Depletion
1985
1995
2005
2015
2025
Global average change in total column ozone as calculated by several modeling
groups for a common scenario of:
Compound
Growth Rate (% per year)
CFCs
CH4
N20
C02
3.0 (emissions)
1.0 (concentrations)
0.25 (concentrations)
-0.60 (concentrations)
Results shown for 2-D models of Isaksen and AER, 1-D models of Brasseur and
Wuebbles, and Conneil's parameterization of the LLNL 1-D model.
Source: Chemical Manufacturers Association (1986); World Meteorological
Organization (1986); Conneil (1986); Brasseur and DeRudder (1986);
and Isaksen and Stordal (1986).
-------
4-10
EXHIBIT 4-5
PERCENT CHANGE IN WEIGHTED UV ENERGY AS A FUNCTION OF
CHANGE IN OZONE ABUNDANCE FOR THREE U.S. REGIONS
DNA-Damage Action
Spectrum Change in UV
Erythema Action
Spectrum Change in UV
Change in Ozone
10% Increase
5% Increase
2% Increase
0 (No Change)
2% Depletion
5% Depletion
10% Depletion
20% Depletion
30% Depletion*
North
-17.3
-9.3
-3.8
0.0
4.2
10.8
22.9
53.8
96.0
Middle
-17.2
-9.1
-3.8
0.0
4.3
10.6
22.8
53.2
94.8
South
-16.7
-8.9
-3.8
0.0
4.2
10.5
22.2
51.0
90.4
North
-14.5
-7.7
-3.2
0.0
3.5
8.9
18.8
43.4
76.5
Middle
-14.4
-7.6
-3.2
0.0
3.5
8.9
18.7
43.1
75.9
South
-14.2
-7.5
-3.1
0.0
3.5
8.8
18.5
42.1
73.1
* For depletion in excess of 30 percent, the following values are
multiplied by the estimated depletion in order to compute changes in
weighted UV radiation flux: DNA-damage: North -- 96.0/30 - 3.2;
Middle -- 94.8/30 - 3.16; and South -- 90.4/30 - 3.01-3; Erythema:
North -- 76.5/30 - 2.55; Middle -- 75.9/30 - 2.53; South -- 73.1/30 •
2:437. Given the fact that UV appears to increase non-linearly with
ozone depletion, this extrapolation is an underestimate.
Source: Based on analyses using the UV Model developed by Serafino
and Frederick (1986). See EPA (1987a) for U.S. region
definitions.
-------
4-11
EXHIBIT 4-6
DOSE-RESPONSE COEFFICIENTS: NONMELANOMA SKIN CANCER
(Whites Only)
DNA-Damaee Action Soectrum
Male
Female
Basal
Male
Female
Low^/
1.42
1.47
0.932
0.316
Middle
2.03
2.22
1.29
0.739
High**/
2.64
2.98
1.65
1.16
Erythema Action
Low^/
1.54
1.57
1.02
0.346
Middle
2.21
2.42
1.41
0.809
Spectrum
High**/
2.88
3.26
1.80
1.27
£ Middle minus one standard error.
£/ Middle plus one standard error.
Source: EPA (1987a).
-------
4-12
that approximately 1 percent of cases result in death. It is further
estimated that 75 percent of these deaths are due to squamous cell carcinoma
and 25 percent to basal cell carcinoma. Given that 80 percent of all
nonmelanoma cases are squamous and 20 percent are basal, this implies
mortality rates of 3.75 percent for squamous cell skin cancer and 0.31 percent
for basal cell skin cancer. To compute the total nonmelanoma deaths due to
ozone depletion, these fractions are multiplied by the projected total of
cases.
Melanona Skin Cancer
The evidence linking UV-B radiation and melanoma skin cancer is summarized
in Chapter 2. In the integrated model, a dose-response equation is used for
projecting increases in melanoma incidence. The model has the same general
form as that for nonmelanoma, but has different dose-response coefficients
based on estimates prepared for EFA's risk assessment and (EPA, l$87a). See
Exhibit 4-7.
Based on the percent change in incidence computed by this dose-response
equation, the projected baseline incidence, and the population size, the total
number of additional melanoma cases is computed.
Increases in mortality from melanoma are calculated based on separate
dose-response coefficients computed by Pitcher (1987). See Exhibit 4-8.
Cataracts
Estimates of the effects of increased UV on cataract incidence are based
on an epidemiological study by Killer, Sperduto, and Ederer (1983), which
related the prevalence of cataracts in 35 locations with a statistical
reconstruction of UV levels. Their regression results are translated into
dose-response models that predict the fractional change in cataract incidence
from a one percent change in ozone. The dose-response coefficients resulting
from this approach are provided in Exhibit 4-9.
Risks to Marine Organisms
The extent to which increased UV radiation levels may affect aquatic
organisms depends on several variables, including the type of water body, the
degree to which UV radiation penetrates the water, the amount of vertical
mixing that occurs, and the seasonal abundance and vertical distributions of
the organisms.
To develop a rough quantification of these effects, a dose-response
relationship was used based on estimates by Hunter, et al. (1982) for anchovy
larvae assuming ocean vertical mixing occurring within the top ten meters of
the ocean. Exhibit 4-10 shows this relationship. Increases in UV-B of less
than 10 percent have little effect due to poor transmission through the ocean
water and the ability of the anchovy population to avoid the increase by
vertical shifts in distribution. Increases above 10 percent begin to affect
-------
4-13
EXHIBIT 4-7
DOSE-RESPONSE COEFFICIENTS:
MELANOMA SKIN CANCER INCIDENCE
(Whites only)
Low^/ Middle High^/
Face. Head and Neck
Male
Female
Trunk and Lower Extremities
Male
Female
0.398 0.512
0.477 0.611
0.200 0.310
0.268 0.412
0.624
0.744
0.420
0.553
£ Middle minus one standard error.
k/ Middle plus one standard error.
Source: Derived from: Scottb and Fears, "The Association
of Solar Ultraviolet Radiation and Skin Melanoma
Among Caucasians in the United States," Cancer
Investigation, in press.
-------
4-14
EXHIBIT 4-8
DOSE-RESPONSE COEFFICIENTS:
MELANOMA SKIN CANCER MORTALITY
(Whites Only)
DNA- Damage Action
Hale
Female
Low^X
0.39
0.25
Middle
0.42
0.29
Spectrum
High&/
0.46
0.33
Ervth
Low^/
0.42
0.28
ema Action
Middle
0.46
0.32
Spectrum
High^/
0.50
0.36
£/ Middle estimate minus one standard error.
&/ Middle estimate plus one standard error.
Source: Pitcher, H.M., "Examination of the Empirical Relationship
Between Melanoma Death Rates in the United States 1950-
1979 and Satellite-Based Estimates of Exposure to Ultra-
violet Radiation." U.S. EPA, Washington, D.C.
March 17, 1987, draft.
-------
4-15
EXHIBIT 4-9
DOSE-RESPONSE COEFFICIENTS: CATARACTS
Middle
0.127 0.225- 0.296
£/ Middle minus one standard error.
k/ Middle plus one standard error.
Source: Derived from data presented in: Miller,
Sperduto, and Ederer, "Epidemiologic
Associations with Cataract in 1971-1972
National Health and Nutrition Examination
Survey, American Journal of Epidemiology.
Vol. 118, No. 2, pp. 239-249, 1983.
-------
4-16
EXHIBIT 4-10
EFFECT OF INCREASED LEVELS OF SOLAR UV-B RADIATION ON THE
PREDICTED LOSS OF LARVAL NORTHERN ANCHOVY FROM ANNUAL POPULATIONS,
CONSIDERING THE DOSE/DOSE-RATE THRESHOLD AND THREE VERTICAL
MIXING MODELS
30
Larval Northern Anchovy
10-m Mixed layer
o-m Mixed layer
0 10 20 30 40 50 60 70
INCREASED UV-B RADIATION (%)
Source: Based on data of Hunter, et al. (1982).
-------
4-17
the anchovy population, with a 60 percent change in UV-B leading to a 25
percent loss in total population. These effects are assumed to be reflected
in commercial harvest levels. For example, it is assumed that a 25 percent
change in survival would lead to a 25 percent decline in harvest.
In'addition to the potential impacts on anchovy harvests, increases in UV-
B would likely have deleterious effects on a wide variety of marine organisms.
Much of the evidence is presented in a summary paper prepared by Worrest
(1983). Unfortunately, effects on other marine life have not been adequately
quantified, and it is thus assumed that the dose-response relationship
developed for anchovy larvae also applies to other commercial fish, including
fin fish'(menhaden, Pacific trawlfish, halibut, sea herring, jack mackerel,
Atlantic mackerel, sablefish, and tuna); and shell fish (clams, crabs,
American lobster, spiny lobster, oysters, shrimp, scallops, and squid). While
clearly speculative, this extrapolation provides one scenario of the
dimensions of the problem. Real damages could be significantly larger or
smaller.
Risks to Crops
Many studies have focused on the effects of UV-B on crops. Unfortunately,
most of these studies were conducted in greenhouses, which do not expose the
plants to natural levels of ambient light. It: has been shown that under
natural lighting conditions, UV-B damage can be ameliorated in_p_lants by
photorepair mechanisms which are not activated in greenhouses. Only one'long
term field study has been, conducted. The EIS analysis relies on the results
of this study, which was conducted by Teramura on the Essex cultivar of
soybean from 1981 to 1986 (Teramura, 1986).
Teramura has analyzed the potential impacts of stratospheric ozone
depletion of up to 25 percent. Although there has been some variation in the
results, the general relationship has been a 0.3 percent decline in yield for
each one percent decrease in stratospheric ozone.
To determine the magnitude of UV-B impacts on agricultural crops, this
relationship is assumed to apply to the major grain crops (wheat, rye, rice,
corn, oats, barely, sorghum, and soybeans) using average annual production
levels from 1980 to 1983. In the absence of crop specific dose-response
relationships, this extrapolation provides one scenario of possible impacts.
Nonetheless, this assumption leads to considerable uncertainty in the
estimates, which could be significantly higher or lower.
The economic effects of the yield reductions is calculated based on the
National Crop Loss Assessment Network (NCLAN) Model, which was originally
developed to assist EPA in setting National Ambient Air Quality Standards for
tropospheric ozone. The NCLAN model computes the annual change in national
economic surplus due to the fractional change in crop yields.
-------
4-18
Impacts Due to Tropospheric Ozone
Increases in UV-B radiation would accelerate the reaction rates of
processes that form tropospheric ozone (smog). Whitten and Gery (1986),
incorporated this effect into current atmospheric models for three cities that
have varying degrees of tropospheric ozone concentrations: Nashville,
Philadelphia, and Los Angeles. The increase in tropospheric ozone reported
below is the average of the results for these three cities.
This analysis considers the effects of increased tropospheric ozone on
agricultural production. The agricultural impacts are evaluated based on
.EPA's National Crop Loss Assessment Model (Rowe and Adams, 1987), which is
described above. Because of a lack of adequate data, the analysis does not
include the effects of tropospheric ozone on acute respiratory disfunction,
such .as shortness of breath.
Degradation of Polymers
To determine the effect of increased UV radiation on polymers, it is
assumed that polymer manufacturers will increase the amount of light
stabilizers in the polymer to counteract the effects of higher UV radiation
levels. Andrady (1986) developed a dose-response model for one type of
outdoor plastic, polyvinlychloride, that predicts the average amount of
stabilizer required as a result of increases in UV-B. This dose-response
model is assumed to apply to other outdoor plastics in luding polyesters,
polycarbonates and acrylics.
Based on the projected size of the outdoor plastics market (Horst et al.,
1986), the total physical amount of increased stabilizer is computed. The
economic implications of this change include the costs of the stabilizers
themselves and the capital cost required to reformulate the plastics.
Global Climate Change and Sea Level Rise
Because they are radiatively active gases that, like carbon dioxide,
absorb outgoing infrared radiation, increased concentrations of CFCs are
expected to contribute to global climate change. Although many environmental
concerns are likely to result from projected global warming, because of the
limited information currently available, only the effects of sea level rise
are considered in this analysis.
Other possible impacts of global climate change include: loss of crops
and forests due to shifts in temperature and precipitation; changes in water
availability with resulting impacts on water quality and the availability of
drinking water; effects on wetlands, other natural ecosystems, and endangered
species; and shifts in hurricane frequency and tracks and storm patterns.
Additional research in each of these areas is essential to better
understanding the potential impacts related to climate change.
As global warming occurs, sea level rise is likely to occur due to three
basic mechanisms: the warming and expansion of the upper layers of the oceans;
-------
4-19
the melting of alpine glaciers; and the melting and disintegration of polar
ice sheets in Greenland and Antarctica.
Using a model originally developed by Lacis (1981) that evaluates the
expected change in average air temperature due to trace gas concentrations,
sensitivity to greenhouse-gas forcings, and heat transport into the oceans,
the rise in global temperature and sea level is projected.
The economic implications of sea level rise were only calculated assuming
that anticipatory actions are taken to limit damages, and only include damage
to major U.S. ports based on case studies prepared for Charleston, South
Carolina and Galveston, Texas (Gibbs, 1984).
General Modelling Assumptions
The integrated model used in this analysis is subject to several
limitations. Although it projects global ozone levels, it only evaluates
damages for the United States. Also, because of limited research to date,
many impacts of ozone depletion are not quantified. Health effects that are
not quantified include: actinic keratoses; suppression of the human immune
system; impacts of tropospheric ozone on the pulmonary system; and pain and
suffering from skin cancer.
Environmental effects that are not quantified include: beach erosion;
loss of coastal wetlands; effects of UV-B on natural ecosystems; and effects
of tropospheric ozone on other crops, forests, other plant species, and man-
made materials.
Due to the long time scale of the model, many projections and effects are
truncated. Growth in CFC emissions is assumed to stop in 2050. Effects are
not evaluated for populations that are born after 2075. Increases in HCFC-22
and methyl chloroform or HCFC-123 that occur as a result of chemical
substitution for controlled substances is not considered.
Several models were not constructed for high levels of ozone depletion,
and their results are held constant after a certain threshold. For example,
ozone depletion is not computed beyond 50 percent (the range of the LLNL 1-D
model), and anchovy depletion is not calculated for UV-B increases greater
than 60 percent.
HEALTH AND ENVIRONMENTAL CONSEQUENCES OF EIS ALTERNATIVES
This section presents estimates of health and environmental effects that
can occur due to ozone depletion under the seven EIS alternatives.^ The
analysis starts with projections of ozone depletion. Health and environmental
consequences of the ozone depletion estimated for each alternative are
presented next.
seven EIS alternatives are defined in Chapter 3.
-------
4-20
Projected Ozone Depletion
1. No Controls Alternative
The No Controls alternative (EIS alternative 1) assumes that no action is
taken to limit the use of CFCs and halons; the United States does not ratify
the Montreal Protocol, which fails to enter into force; and neither the United
States nor other nations take unilateral controls.
Exhibit 4-11 displays estimates of ozone depletion over time for the No
Controls alternative. As shown in the exhibit, the horizontal axis is time
(1985 to 2075) and the vertical axis is the level of global ozone depletion
simulated to occur'. Note that ozone depletion is identified as negative, so
that increasing levels of ozone depletion are depicted as downward sloping
curves.
The No Controls case shows average column ozone depletion of 2 percent by
the year 2015 from 1985 levels; depletion that may have occurred prior to 1985
is ignored. Note that depletion continues to get worse after 2050 when
CFC/halon use is assumed arbitrarily to level out. The depletion continues
because the concentrations of chlorine and bromine in the stratosphere do not
reach steady-state by 2050, and concentrations continue to increase even
though emissions are held constant.
2. Montreal Protocol
Exhibit 4-11 also displays estimates of global ozone depletion assuming
global ratification and implementation of the Montreal Protocol (EIS
alternative 2). As shown in the exhibit, the Montreal Protocol results in
substantially less ozone depletion. Under the protocol, ozone depletion
reaches only 1.3 percent by 2075 compared to approximately 40 percent in the
No Controls alternative.
3. Other Control Cases
Ozone depletion estimates for alternative control cases are presented in
Exhibit 4-12.2 Note that in the Protocol/U.S. 80% alternative, the U.S., by
taking more stringent action than required by the Protocol, could achieve
slightly less ozone depletion compared to the Protocol case. If the Protocol
fails to enter into force, unilateral action by the U.S. (Unilateral U.S. --
EIS alternative 4) allows more depletion compared to the Protocol alternative
but substantially less than No Controls (see Exhibit 4-11).
Chapter 3 for a complete definition of these alternative control
levels.
-------
4-21
EXHIBIT 4-11
GLOBAL OZONE DEPLETION FOR THE
NO CONTROLS ALTERNATIVE AND PROTOCOL ALTERNATIVE
(Percent)
-40.0
1985
2015
2030
2045
2060
2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFG and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-22
EXHIBIT 4-12
GLOBAL OZONE DEPLETION ESTIMATES
FOR EIS ALTERNATIVES 3-7
(Percent)
85% REDUCTION
PROTOCOL/U.S. 80%
L 20% REDUCTION
1985 2000 2015 2030 2045 2060 2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-23
Exhibit 4-13 summarizes ozone depletion estimates for all seven EIS
alternatives in tabular form. For each alternative, estimated ozone depletion
is listed for the years 2000, 2025, 2050, and 2075. As expected, the more
stringent control policies (e.g., alternatives 3 and 7) result in less ozone
depletion.
Human Health Effects
1. Nonmelanoma Skin Cancer
The EIS alternatives result in different amounts of ozone depletion
between now and the year 2075. These differences can be expected to cause
people born through 2075 to experience different increases in lifetime
exposures to UV radiation. Differences in cumulative lifetime exposures, in
turn, result in different estimates of additional nonmelanoma skin cancer
cases and deaths for the EIS alternatives.
Exhibit 4-14 shows the additional number of nonmelanoma cases estimated to
occur in people born by 2075 by type of nonmelanoma. These estimates are
incremental to the number of cases expected in the absence of ozone depletion.
Without this depletion, an estimated 160 million cases of basal and squamous
cancers would occur for people born by 2075, indicating that skin cancer
already is a serious problem. Of the additional cases estimated for the EIS
alternatives, the vast majority of cases occur in people not yet born (e-^.,
people born between 2029 and 2075).
Based on estimates of the fraction of nonmelanoma skin cancer cases that
result in death, Exhibit 4-15 presents projected additional deaths from
nonmelanoma cancers for the EIS alternatives. Nonmelanoma skin cancer deaths
among people born before 2075 assuming no ozone depletion are estimated at 1.8
million.
2. Melanoma Skin Cancer
Increases in melanoma skin cancer cases and deaths due to ozone depletion
estimated for the EIS alternatives are shown in Exhibit 4-16. In the absence
of depletion, some 4.2 million melanoma skin cancer cases would be expected
for people born before 2075. The majority of additional cases and deaths
estimated for this population group and shown in Exhibit 4-16 occur in later
generations. As expected, increasing levels of CFC and halon reduction result
in fewer additional cases and deaths.
3. Cataracts .
Based on the linkage between changes in ozone depletion and changes in
human exposure to UV radiation, Exhibit 4-17 provides estimates of the
-------
4-24
EXHIBIT 4-13
SUMMARY OF GLOBAL OZONE DEPLETION
ESTIMATES FOR EIS ALTERNATIVES
(Ozone Depletion Reported in Percent)
1.
2.
3.
4.
5.
6.
7.
EIS Alternative
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S. 50%
Freeze
20% Reduction
85% Reduction
2000
0.9
0.8
0.8
0.8
0.8
0.8
0.8
2025
3.9
1.3
1.2
3.1
2.6
1.9
0.8
2050
12.4
1.6
1.4
8.5
4.3
3.4
0.6
2075
39.9
1.3
1.2
20.4
6.2
5.0
0.0
-------
4-25
EXHIBIT 4-14
ADDITIONAL CASES OF NONMELANOMA SKIN CANCER
IN THE U.S. FOR PEOPLE BORN BY
1.
2.
3.
4.
5.
6.
7.
EIS Alternative
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
(Whites
Ozone Depletion
by 2075
(percent)
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Only)
Basal
79,727,700
2,337,300
2.119,000
49,394,900
9,560,800
7,500,700
408,200
2075
Squamous
73,959,400
1,347,600
1,217,000
41,603,600
5,914,100
4,577,900
189,500
Total
153,687,100
3,684,900
3,336,000
90,998,500
15,474,900
12,078,600
607,700
-------
4-26
EXHIBIT 4-15
ADDITIONAL DEATHS FROM NONMELANOMA SKIN CANCER
IN THE U.S. FOR PEOPLE BORN BY 2075
(Whites Only)
Ozone Depletion
by 2075
EIS Alternative (percent) Basal
1.
2.
3.
4.
5.
6.
7.
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
39.9
1.3
1.2
20.4
6.2
5.0
0.0
247,100
7,200
6,700
153,100
29,700
23,300
1,300
Squamous
2,773,400
50,500
45,700
1,560,100
221,800
171,600
7,600
Total
3,020,500
57,700
52,400
1,713,200
251,500
194,900
8,900
-------
4-27
EXHIBIT 4-16
MELANOMA SKIN CANCER: ADDITIONAL CASES AND
DEATHS IN THE U.S. FOR PEOPLE BORN BY 2075
(Whites Only)
Ozone Depletion
by 2075
EIS Alternative (percent)
1.
2.
3.
4.
5.
6.
7.
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Additional Cases
782,100
34,300
31,400
507,300
125,900
100,000
8,300
Additional Deaths
186,900
7,900
7,200
124,600
30,200
23,900
1,700
-------
4-28
EXHIBIT 4-17
ADDITIONAL CATARACT CASES IN THE
1.
2.
3.
4.
5.
6.
7.
U.S. FOR
EIS Alternative
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
PEOPLE BORN BY 2075
Ozone Depletion
by 2075
(percent)
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Additional Cases
18,171,000
6U.200
554,800
13,066,600
2,847,200
2,234,200
228,700
-------
4-29
additional number of cataract cases that can be expected in the U.S. under the
EIS alternatives. The number of additional cases expected for people born
before 2075 is very sensitive to the levels of CFC and halon reduction
achieved. Global implementation of the Montreal Protocol (EIS alternative 2)
results in 96 percent fewer additional cases compared to the No Controls
alternative.
Environmental Effects
1. Risks to Marine Organisms
The anchovy larvae dose-response relationship described above was used to
develop a rough estimate of damages to marine organisms likely to occur due to
ozone depletion. This dose-response relation is used as a measure of
potential impacts on all major commercial aquatic organisms, including fin
fish and shell fish. Extrapolating the dose-response relationship estimated
for anchovy larvae to other species is highly uncertain, and effects estimated
from this relationship may be higher or lower. This relationship is used,
however, because it represents the best available basis for assessing risks to
marine organisms.
Exhibit 4-18 summarizes potential decreases in commercial fish harvests
associated with the EIS alternatives and the- expected value of these
decreases. Note certain alternatives (e.g., U.S. ratification and global
implementation of the protocol) eliminate risks to marine organisms, implying
that increased U.S. controls would achieve no marginal benefit. This finding
is an artifact of the anchovy dose-response model, in which increases in UV
radiation of less than ten percent have no effect on survival rates.
2. Risks to Crops
Extrapolating from the dose-response model for the Essex cultivar of
soybean, which was described above, the percent decline in grain harvest was
calculated for each EIS alternative. The harvest declines were valued based
on the NCIAN model. Exhibit 4-19 shows the harvest decline and economic
effect of each EIS alternative. Because the estimates shown in the exhibit
are based on analysis of a single cultivar, the estimates must be considered
highly extrapolative; actual risks to crops could be significantly greater or
lower. In addition, ozone depletion greater than 25 percent is assumed not to
affect crop yields; larger depletion is outside the valid range of the dose-
response model used in this analysis.
3. Impacts Due to Tropospheric Ozone
Using the results of Whitten and Gery's case studies of three U.S.
cities, the percent increase in tropospheric ozone was calculated for each EIS
alternative. The economic effect of increased tropospheric ozone was
evaluated only for damage to major agricultural losses, based on the NCLAN
model. The results are shown in Exhibit 4-20.
-------
4-30
EXHIBIT 4-18
DECLINE IN U.S. COMMERCIAL FISH HARVESTS
DUE TO INCREASED UV RADIATION^/
Ozone Depletion
by 2075
EIS Alternative (percent)
1.
2.
3.
4.
5.
6.
7.
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Harvest Decrease
by 2075
(percent)^
>25.0
0.0
0.0
24.0
1.7
0.2
0.0
Value of Decrease^/
(billions of 1985 $)
5.5
0.0
0.0
3.11
0.13
<0.01
0.0
» Extrapolated from dose-response relationship estimated for anchovy larvae.
«/ UV radiation increases above 60 percent were assumed not to have any
additional effects on harvest levels; this assumption was made to avoid
extrapolating beyond the range analyzed by Hunter, Kaupp, and Taylor (1982).
£/ Value assessed using a discount rate of two percent.
-------
4-31
EXHIBIT 4-19
DECLINE IN MAJOR GRAIN CROP HARVESTS IN THE U.S.
DDE TO INCREASED UV RADIATION
Ozone Depletion
by 2075
EIS Alternative (percent)
1.
2.
3.
4.
5.
6.
7.
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Harvest Decrease
by 2075
(percent)^
>7.5
0.4
0.4
6.1
1.9
1.5
0.0
Value of Decrease^/
(billions of 1985 $)
28.92
5.53
5.26
20.74
11.32
9.45
3.43
» Value assessed using a discount rate of two percent.
-------
4-32
EXHIBIT 4-20
INCREASE IN TROPOSPHERIC OZONE (SMOG)
AND LOSS IN MAJOR GRAIN CROP PRODUCTION
IN THE U.S.
Increase in
Tropospheric Ozone
by 2075
EIS Alternative (percent)
1.
2.
3.
4.
5.
6.
7.
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
>30.9
1.1
1.0
17.7
5.2
4.1
<0.01
Value of Damage to
Major Grain Crops
(billions of 1985 $)£/
14.9
2.5
2.4
9.7
5.2
4.5
1.6
Value assessed using a discount rate of two percent.
-------
4-33
4. Degradation of Polymers
Based on the dose-response model developed by Andrady for
polyvinylchloride, the impact of UV radiation on polymers was estimated for
the EIS alternatives. This impact was assessed as the cost of adding light
stabilizer in polymers to counteract the effects of higher UV radiation
levels. Impacts on polymeric materials currently in use are ignored. The
results of this analysis are shown in Exhibit 4-21. Note that the maximum
allowable increase in light stabilizers was constrained at 25 percent, a limit
that is reached in the No Controls alternative.
5. Global Climate Change and Sea Level Rise
The EIS alternatives, by controlling the future emissions of CFCs and
halons, which are greenhouse gases, will influence the magnitude and timing of
global climate change and its effects, including sea level rise. Exhibit 4-22
shows the equilibrium temperature rise and the sea level rise associated with
each alternative. Changes in temperature which are responsible for sea level
increases could be greater or smaller depending on the actual responsiveness
of the atmosphere to increases in greenhouse gases. In addition, Exhibit 4-22
shows the costs of damage to major U.S. ports induced by sea level rise.
PROJECTED OZONE DEPLETION FOR SENSITIVITY CASES
The estimates of ozone depletion for the EIS alternatives are sensitive to
numerous assumptions. This section displays estimates of projected future
depletion for a series of sensitivity cases that vary key assumptions. The
assumptions that are considered include:
o chemical coverage -- controls on halons are omitted;
o stringency -- the implications of requiring developing
nations and the USSR to follow the timetable of reductions
set for other developed nations are analyzed;
o participation -- the percentage of worldwide compound
production that is subject to protocol controls is varied;
o
future growth in trace gases -- the rate of growth in
greenhouse gases (CC^, ^0, and CH^) is analyzed as a
sensitivity; and
^Equilibrium temperature is that temperature reached when incoming
radiation is roughly equivalent to outgoing radiation.
-------
4-34
EXHIBIT 4-21
COSTS OF ADDING UV STABILIZERS
IN RESPONSE TO OZONE DEPLETION
1.
2.
3.
4.
5.
6.
7.
EIS Alternative
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
Ozone Depletion
by 2075
(percent)
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Cost of Adding
UV Stabilizers
(billions of 1985 $)£/
4.69
1.-57
1.57
3.98
2.32
1.90
0.42
Value assessed using a discount rate of two percent.
-------
4-35
EXHIBIT 4-22
PROJECTED SEA LEVEL RISE AND DAMAGE TO U.S. COASTAL PORTS
1.
2.
3.
4.
5.
6.
7.
EIS Alternative
No Controls
Protocol
Protocol/U.S. 80%
Unilateral U.S.
Freeze
20% Reduction
85% Reduction
Ozone
Depletion
by 2075
(percent)
39.9
1.3
1.2
20.4
6.2
5.0
0.0
Equilibrium Sea Level
Global Warming Rise by
by 2075 (°C) 2075
5.8
4.3
4.3
5.4
4.7
4.5
4.3
97.8
86.7
86.5
94.7
89.4
88.4
85.3
Valuation
of Sea. Level
Rise Impacts
Impacts on
Ports^/
(billions
of 1985 $)
54.4
50.1
50.0
53.2
51.1
50.7
49.5
Value assessed using a three percent discount rate.
-------
4-36
o growth in consumption and production in CFCs and halons -- the effect
of varying assumptions about the growth of ozone depleting compounds
in the absence of controls is investigated.
The definitions of these sensitivity cases are provided in Chapter 3.
The results of this sensitivity analysis are presented in a series of
graphs and in a final sensitivity table.. Each graph shows projected ozone
depletion estimates for the Montreal Protocol (EIS alternative 2) and for the
protocol under one"or more sensitivity cases.
The results of this sensitivity analysis lead to the following principal
conclusions:
o Excluding halons from control results in increased ozone
depletion (Exhibit 4-23). If halons are excluded, ozone
depletion reaches 3.2 percent.by 2075 compared to 1.3
percent for complete protocol requirements;
o Requiring the USSR and developing nations to follow the
schedule of reductions set for other developed countries
and to base future compliance with protocol requirements on
their 1986 levels of production would lead to small
reduction in depletion (Exhibit 4-24). If the U.S.S.R. did
not join, however, or if compliance rates in LDCs were
lowered, say to 40 percent, the impact would be to weaken
the performance of the protocol (Exhibits 4-25 and 4-26);
o Ozone depletion is sensitive to worldwide participation in
the protocol (Exhibit 4-27). For sensitivity case
assumptions, ozone depletion by 2075 ranges from 0.5 to 2.6
percent depending upon participation rates;
o Trace gases tend to counter ozone depletion. Increasing
the rate of growth in these gases lowers ozone depletion
and results in ozone abundance for the high trace gas
growth sensitivity (Exhibit 4-28).
o Estimates of ozone depletion would be higher if larger
growth rates were used for production and consumption of
ozone depleting compounds (Exhibit 4-29). Depletion for
the high growth rate sensitivity in 2075 is approximately 6
percent, more than 4 times the depletion estimated for the
Protocol alternative (EIS alternative 2).
-------
4-37
EXHIBIT 4-23
GLOBAL OZONE DEPLETION ESTIMATES:
CHEMICAL COVERAGE SENSITIVITY CASE
2.0
Q.
O
Q
9
c
o
N
O
"3
o
1.0 -
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
NO HALON CONTROLS
1985
2000
2015
2030
2045
2060
2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFG and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-38
EXHIBIT 4-24
GLOBAL OZONE DEPLETION ESTIMATES:
STRINGENCY SENSITIVITY CASES
e
o
o
c
o
N
O
75
A
o
O
2.0
1.0 -
0.0
-1.0
-2.0
-3;0
-4.0
-5.0
-6.0
DEVELOPING NATIONS 1986 BASE LEVELS
PROTOCOL
USSR <•> 1986 BASE LEVELS
1985
2000
2015
2030
1
2045
2060
2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-39
EXHIBIT 4-25
GLOBAL OZONE DEPLETION ESTIMATES:
STRINGENCY SENSITIVITY CASES-
VARYING USSR PARTICIPATION LEVELS
C
o
e
e
o
N
O
o
O
USSR 9 1986 BASE LEVELS
i 1
USSR
NONPARTICIPATION
-6.0
1985
2000
2015
2030
2045
2060
2075
USSR 0 1986 Base Levels and Protocol cases assume that: (1) developed
nations outside the U.S. representing 94 percent of CFC and halon
consumption in these developed nations participate; and (2) developing
nations representing 65 percent of consumption in developing nations
participate. USSR Nonparticipation case assumes that USSR does not
participate in controls.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-40
EXHIBIT 4-26
GLOBAL OZONE DEPLETION ESTIMATES:
STRINGENCY SENSITIVITY GASES --
VARYING DEVELOPING NATIONS PARTICIPATION
2.0
1.0 -
~ o.o 4
c
JO
3j -1.0 -\
"5.
«
Q -2.0 -
0
-3.0 H
-4.0 -
-5.0 -
-6.0
DEVELOPING NATIONS D 1986 BASE LEVELS
DEVELOPING NATIONS 0 1986 BASE LEVELS;
40% PARTICIPATION
PROTOCOL
1985 2000 2015 2030 2045 2060
2075
Developing Nations (3 1986 Levels and Protocol cases assume that: (1)
developed nations outside the U.S. representing 94 percent of CFG and
halon consumption in these developed nations participate; and (2)
developing nations representing 65 percent of consumption in developing
nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-41
EXHIBIT 4-27
GLOBAL OZONE DEPLETION ESTIMATES:
GLOBAL PARTICIPATION SENSITIVITY CASES
2.0
o
o
N
O
O
1.0 -
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
HIGH
PARTICIPATION
i 1 1 1
LOW
PARTICIPATION
1985
2000
2015
2030
2045
2060
2075
High Participation case assumes 100 global participation. Protocol case
assumes that: (1) developed nations outside the U.S. representing 94
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate. Low Participation case
assumes that: (1) developed nations outside the U.S. representing 75
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 40 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-42
EXHIBIT 4-28
GLOBAL OZONE DEPLETION ESTIMATES:
TRACE GAS GROWTH SENSITIVITY CASES
•
Q
«
C
o
N
O
o
O
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
HIGH TRACE
GAS GROWTH
LOW TRACE
GAS GROWTH
GLOBAL WARMING
LIMITED TO 2*C
1985
2000
1
2015
2030
2045
1
2060
2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-43
EXHIBIT 4-29
GLOBAL OZONE DEPLETION ESTIMATES:
BATE OF COMPOUND GROWTH SENSITIVITY CASES
c
JO
"S
SL
"o.
•
a
9
C
O
N
O
75
.a
o
a
LOW COMPOUND
GROWTH
HIGH COMPOUND
GROWTH
-6.0
1985
2000
2015
2030
2045
2060
2075
Assumes that: (1) developed nations outside the U.S. representing 94
percent of CFC and halon consumption in these developed nations
participate; and (2) developing nations representing 65 percent of
consumption in developing nations participate.
Source: Estimates based on statistical method developed by Connell
(1986).
-------
4-44
EXHIBIT 4-30
SUMMARY OF GLOBAL OZONE DEPLETION ESTIMATES
FOR EIS SENSITIVITY CASES
(Ozone Depletion Reported in Percent)
Sensitivity Case 2000 2025 2050 2075
Reference Case:
EIS Alternative 2 (Protocol) 0.8 1.3
Chemical Coverage:
No Halons
Stringency:
USSR @ 1986 Base Levels
USSR Nonparticipation
Developing @ 1986 Base Levels
Developing @ 1986 Levels:
40% Participation
Participation:
Low Participation
High Participation
Trace Gas Growth:
Low Trace Gas Growth
High Trace Gas Growth
Global Warming Limited (2eC)
Rate of Compound Growth:
Low Compound Growth
High Compound Growth
0.8
0.8
0.8
0.8
0.7
0.8
0.8
0.9 '
0.7
0.9
0.7
0.8
1.5
1.1
1.7
1.0
1.3
1.6
1.2
1.8
0.8
2.4
0.8
2.0
2.3
1.2
2.9
1.1
1.7
2.3
1.1
2.5
0.3
3.9
0.4
4.0
. 3.2
0.8
4.2
0.7
1.7
2.6
0.5
2.9
-1.3&/
5.1
-0.3fi/
5.8
» Negative number indicates ozone abundance (in percent).
-------
4-45
REFERENCES
Andrady, A. (1986), Analysis of Technical Issues Related to the Effect of UV-B
on Polymers. Research Triangle Institute, Research Triangle Park, NC
CMA (1986), Production. Sales, and Calculated Release of CFC-11 and CFC-12
Through 1984. Chemical Manufacturers As-sociation, Washington, D.C.
Connell, Peter S. (1986), A Parameterized Numerical Fit to Total Column Ozone
Changes Calculated by the LLNL 1-D Model of the Troposphere and Stratosphere.
Lawrence Livermore National Laboratory, Livermore, California.
DuPont (1987) DuPont Estimates of Per Capita Consumption of CFCs, provided to
EPA.
EPA (1987a), Assessing the Risks of Trace Gases That Can Modify the
Stratosphere. U.S. Environmental Protection Agency, Washington, D.C.
EPA (1987b), Regulatory Impact Analysis: Protection of Stratospheric Ozone.
U.S. Environmental Protection Agency, Washington, D.C.
Gibbs, Michael J. (1984) "Economic Analysis of Sea Level Rise: Methods and
Results." In Earth and Titus (eds.) Greenhouse Effect and Sea Level Rise:
'A Challenge for This Generation. Van Nostrand Reinhold, NY.
Gibbs, Michael J. (1986), Scenarios of CFC Use: 1985 to 2075. prepared for the
U.S. Environmental Protection Agency, Washington, D.C.
Hammitt, James K., et al. (1986), Product Uses and Market Trends for Potential
Ozone Depleting Substances: 1985 - 2000. The RAND Corporation, prepared for
the U.S. Environmental Protection Agency, Washington, D.C.
Killer, R., R. Sperduto, and F. Ederer (1983), "Epidemiologic Associations
with Cataract in the 1971-1972 National Health and Nutrition Examination
Survey," American Journal of Epidemiology. Vol. 118, No. 2, pp. 239-248.
Horst, R. , K. Brown, R. Black, and M. Kianka, The Economic Impact of Increased
UV-B Radiation on Polymer Materials: A Case Study of RJEid PVC. Mathtech,
Inc., Princeton, New Jersey.
Hunter, J.R., S.E. Kaupp, and J.H. Taylor (1982). "Assessment of Effects of UV
Radiation on Marine Fish Larvae." In: Calkins, J. (ed.) The Role of Solar
Ultraviolet Radiation in Marine Ecosystems. pp. 459-497, Plenum, New York.
Isaksen, I.S.A. and F. Stordal (1986), "Ozone Peturbations by Enhanced Levels
of CFCs, N2© and CH^.: A Two-Dimensional Diabatic Circulation Study Including
Uncertainty Estimates," Journal of Geophysical Research. 91 (D4), 5249-5263.
-------
4-46
Isaksen, I.S.A. (1986), "Ozone Perturbations Studies in a Two-Dimensional
Model with Temperature Feedback in the Stratosphere Included," presented at
UNEP Workshop on the Control of Chlorofluorocarbons, Leesburg, Virginia,
September 1986.
ITC (1986), Synthetic Organic Chemicals. U.S. International Trade Commission,
Washington, D.C.
Kurosawa, K. and K. Imakezi (1986), "Projections of the Production Use and
Trade of CFCs in Japan in the Next 5-10 Years," Japan Fluoride Gas Association
and the Japan Aerosol Association.
Lacis, A., J.E. Hansen, P. Lee, T. Mitchell, and S. Lebedeff (1981)
"Greenhouse Effect of Trace Gases, 1970-1980," Geophysical Research Letters
8:(10), pp.1035-1038.
National Academy of Sciences (NAS) (1984), Causes and Effects of Changes in
Stratospheric Ozone. National Academy Press, Washington, DC.
Nordhaus, William D. and G.W. Yohe (1986) Probabilistic Projections of
Chlorofluorocarbon Consumption. y*le University and Wesleyan University,
prepared for the U.S. Environmental Protection Agency, Washington, D.C.
Pitcher, H.M. (1987) Examination of the Empirical Relationship Between
Melanoma Death Rates in the United States 1950-1979 and Satellite-Based
Estimates of Exposure to Ultraviolet Radiation. Unpublished manuscript, in
press.
Quinn, Timothy H., et al. (1986), Projected Use. Emissions, and Banks of
Potential Ozone-Depleting Substances. The RAND Corporation, prepared for the
U.S. Environmental Protection Agency, Washington,D.C.
Rowe, R.D. and R.M. Adams (1987), Analysis of Economic Impacts of Lower Crop
Yields Due to Stratospheric Ozone Depletion. Draft Report for the U.S.
Environmental Protection Agency, Washington, D.C.
Scotto, J. (1986) "Nonmelanoma Skin Cancer -- UV-B Effects." In: Effects of
Changes in Stratospheric Ozone and Global Climate. Volume 2: Stratospheric
Ozone. Titus, J. (ed). 'United Nations Environment Programme, United States
Environmental Protection Agency, p. 34.
Scotto, J., and T.R. Fears (1986), "The Association of Solar Ultraviolet
Radiation and Skin Melanoma Among Caucasians in the United States." Cancer
Investigations In press.
Serafino, G.N., and Frederick, J.E. Global Modeling of the Ultraviolet Solar
Flux Incident on the Biosphere. In Press 1986.
Teramura, Alan H. (1986) Current Risks and Uncertainties of Stratospheric
Ozone Depletion Upon Plants. University of Maryland, College Park, Maryland.
-------
4-47
UNEP (1986), Report of the First Part of the Workshop on the Control of
Chlorofluorocarbons. United Nations Environment Programme, UNEP/WG.148/2,
Nairobi, Kenya.
Whitten, Gary Z., and M.W. Gery (1986) "Effects of Increased UV Radiation on
Urban Ozone," Presented at EPA Workshop on Global Atmospheric Change and EPA
Planning. Edited by Jeffries, H., EPA Report # 600/9-86016 July 1986.
WHO (1986), Atmospheric Ozone 1985. Assessment of Our Understanding of the
Processes Controlling its Present Distribution and Change. World
Meteorological Organization Global Ozone Research and Monitoring Project --
Report No. 16, Geneva, Switzerland.
Worrest, R.C. (1983), "Depletion of Stratospheric Ozone: Impact of UV-B
Radiation Upon Nonhuman Organisms." In: Covello, V., et al. (eds.) The
Analysis of Actual Versus Perceived Risks, pp 303-315, Plenum Press, New York.
Zhijia, W. (1986), "Country Paper for Topic I: UNEP Workshop on the
Protection of the Ozone Layer," National Environmental Protection Agency of
the People's Republic of China.
-------
CHAPTER 5
SOCIO-ECONOMIC COSTS OF ALTERNATIVES
ABSTRACT
This chapter presents estimates of socio-economic costs for the U.S. of
foregoing the use of CFCs and halons as would be required under various
possible alternatives related to stratospheric protection. Socio-economic
costs are estimated for the U.S. for the following alternatives:
o Protocol -- U.S. ratification and implementation of the Montreal
Protocol.
o Protocol/U.S. 80% -- U.S. ratification of'the Protocol and
domestic regulations that require additional reductions of
80 percent in the use .of CFCs by 2004.
o Freeze -- the U.S. implements only the first stage of
Protocol controls, a freeze on CFC use at 1986 levels
starting in 1990.
o 20% Reduction -- the U.S. implements only the first two
stages of the Protocol, a freeze on CFC use and reduction
of 20 percent in GFC use in 1993.
o 85% Reduction -- the U.S. ratifies the Protocol but
implements a reduction of 85 percent in 1999. This
reduction exceeds the Protocol requirement of 50 percent in
1999.
These scenarios represent alternative levels of CFC control in the U.S.
These scenarios correspond to the EIS Alternatives described in Chapter 3;
however, because the levels of U.S. reductions are the same for several of the
alternatives described in Chapter 3, socio-economic costs have been estimated
only for the set of scenarios shown above.
The first two sections of this chapter define socio-economic costs and
describe the methods used to estimate these costs. The next section presents
cost estimates for the control levels. The possible health, safety, and energy
implications of chemical substitution are discussed next, and a final section
examines trade issues.
DEFINITION OF SOCIO-ECONOMIC COSTS
For purposes of estimating socio-economic costs, this EIS narrowly defines
these costs to include:
-------
5-2
o real resource costs incurred by society in response to
government-imposed restrictions on the domestic use of CFCs
and halons ,
o possible health, environmental, and energy consequences
arising from the measures taken by industries to reduce
their consumption of the compounds; and
o possible effects on international trade.
Other important socio-economic impacts such as effects on human health, plants,
agriculture, and aquatic organisms were described in Chapter 4.
METHODS USED TO ESTIMATE SOCIAL COSTS
The methods and data used in this EIS to estimate the social costs of the
EIS alternatives are described in EPA's recent Regulatory Impact Analysis:
Protection of Stratospheric Ozone (EPA, 1987b). The technical appendix from
the RIA describing EPA's cost analysis approach is included as Appendix C to
this EIS.
The basic method for estimating social costs is to measure decreases in
society's welfare attributable to reduced availability of CFC-using products.
The technique adopted for this purpose is the measurement of decreases in
producer and consumer surplus in the relevant markets that result from
regulatory restrictions on CFC use. Consumer surplus represents the loss in
satisfaction to consumers of CFC-using products. Producer surplus represents
the loss in income to the owners of factors of production used in manufacturing
CFC-using products. The relevant markets are.
o the markets for the various CFC compounds, i.e, the
markets in which CFCs are sold by producers of these
compounds to the various CFC-using industries (e.g., the
market for CFC-11); and
o the markets for the outputs of the CFC-using industries,
i.e., the markets in which the products of the CFC-using
industries are sold to consumers (e.g., the market for
foam-based packaging materials.)
The initial impact of any system of CFC regulation is to reduce the supply
of CFCs and therefore to increase CFC prices. Demands for CFCs are "derived
demands" because they are derived from manufacturers' desires to meet the
1 Unless specified, the following sections generally refer only to CFCs
but include impacts on the three regulated halons.
r\
*• This analysis assumes that the markets for complements and substitutes
for the output of CFC-using industries do not experience price changes.
Consequently, there is no welfare change in these markets.
-------
5-3
demands of consumers for final products. Because CFCs are used as inputs to
many products, e.g., insulating foams, air conditioners, etc., the increases in
CFC prices will cause accompanying increases in the costs of supplying these
products. Ultimately, the costs borne by society due to CFC regulation will be
reduced consumption and increased prices of all products that currently use or .
would potentially, use CFCs as an input. The reduced satisfaction which society
will receive from these products is the real economic cost of CFC regulation.
Estimating the full cost burden to society requires careful attention to the
modeling of all likely changes in both relevant markets -- outputs of CFC-using
industries and CFC markets themselves. "The discussion below first examines the
nature of CFC demands, which are closely related to the supply decisions of
CFC-using industries. Next, it considers the nature of CFC supply. Finally, it
describes how information about the demand and supply of CFCs is used to
estimate the costs of CFC regulation.
Demand for CFCs
The demands for CFCs are largely determined, by the choices made by both
buyers and sellers of CFC-using products. Three possible adjustments could
occur in CFC-using markets as a result of regulation-induced CFC price
increases:
o switches from CFC-using products to other products;
o switches to production processes that use fewer CFCs per
unit of output; and
o switches from CFC-using production processes to ones using
other chemicals.
Each of these adjustments would change the quantity of CFCs demanded by
industry. Alternatively, CFC-using markets could do nothing and simply pay
higher prices for CFCs, in which case no change in CFC demand would occur.
An example of the first type of adjustment is the replacement of CFC-based
foam egg cartons with paper-based egg cartons. The result of this type of
adjustment is a reduction in CFC demand that is directly proportional to the
extent to which, the substitute product, in this case, paper egg cartons,
penetrates the CFC blown egg carton's market. In the extreme case in which the
CFC price rise is large and CFCs comprise a large share of the product costs,
the penetration could be complete and the demand for CFCs from this type of
product could fall to zero.
An example of the second type of adjustment is the use of recovery and
recycling equipment to collect and recycle CFC emissions during the production
of computer chips. Because collection and recycling result in significantly
less CFC usage in the manufacturing process, the installation of this equipment
would partially reduce the demand for CFCs from this type of product.
An example of the third type of adjustment is the use of an ethylene
oxide/carbon dioxide mixture instead of an ethylene oxide/CFC -mixture in the
sterilization of hospital equipment. Here again CFC demand will be reduced to
the extent the new mixture captures a share of the sterilization market. The
-------
5-4
derived CFC demand is reduced to the extent the new chemical captures a share of
the CFC input market.
To model all possible adjustments in production processes and consumer
behavior, this analysis draws on an extensive engineering analyses of
manufacturing processes of CFC-using products. These engineering analyses are
presented in EPA's Regulatory Impact Analysis (EPA, 1987b). These engineering
analyses characterize the substitution possibilities available across 74 use
categories involving 8 broad categories of CFC-consuming industries.
For the 74 applications identified in this analysis, a total of nearly 900
cpntrol possibilities were identified.^ These controls form a "menu" of actions
from which firms within each of the applications may choose to reduce their
consumption of CFCs. Although the identification of control possibilities was
designed to be as comprehensive as possible, additional options may be available
that are not included in the data available for this analysis.
Of note is that not all of the options identified are available immediately.
For each control option an estimate was made of its expected future availability
over time. The following definitions were used:
o short term -- available in 0 to 3 years;
o medium term -- available starting in 4 to 7 years; and
o long term - - available starting in more than 7 years.
Of the nearly 900 control possibilities identified, about 350 were excluded
from further analysis because of factors that make the controls unacceptable for
use by industry, including:
o risk/toxicity;
o technical feasibility;
o cost;
o effectiveness at reducing CFC use;
o enforceability; and
o insufficient data to evaluate the costs and reduction achieved by the
substitute.
For the remaining approximately 550 control options identified, detailed
estimates were prepared concerning the cost of undertaking the control and the
possible reduction in annual CFC use achievable with the control over time.
Control costs include all variable costs, such as material, labor and energy
expenses; capital costs, properly discounted for the expected useful life of the
equipment; and nonrecurring costs, such as the costs of retooling, research and
^ The data on the control possibilities are documented separately in
addenda to EPA's RIA (EPA, 1987b) found in Volume III.
-------
5-5
development expenditures, and training.
Decisions by producers and consumers to switch from one production
technology or product to another were simulated based upon estimates of private
costs as seen by the producers and consumers themselves. Private costs can
differ from social costs because:
o taxes cause gross returns from any investment to differ
from net returns; and
o the discount rate used by firm owners may be higher than
the rate of social discount appropriate for government
decision making.
Social costs usually exceed, private costs because private costs are
measured net of taxes.
The analysis assumes that CFC consumers use a fixed amount of CFCs over a
range of CFC prices until CFC prices rise enough to induce the consumers to
implement the substitution. The derived demand from any particular CFC-using
product therefore will be constant over the some range of CFC prices. The
derived demand curve for CFCs appears as a step function in which each vertical
segment indicates the range of CFC prices over which the technology is preferred
to all others, and each horizontal section represents the reduction in CFC
demand that occurs as manufacturers choose to switch to a new production
technology. The downward sloping curve in Exhibit 5-1 illustrates a derived
demand function. • .
The results of the engineering analyses provide the basis for the
characterization of CFC demand curves for each specific industry. As an example
of how an individual demand curve might be characterized in the analysis,
consider the demand for CFCs from polystyrene foam manufacturers. If CFC price
increases were small -- say $0.10 per kilogram, the least expensive response
from foam manufacturers might be a switch to carbon adsorption to reduce loss of
CFCs during the production process. This technology might be estimated to save
about five percent of total CFC usage in this industry. If CFC price increases
were higher -- say $0.25 per kilogram, the increased CFC price might induce some
foam manufacturers to switch to the use of HCFC-22 or pentane as a blowing
agent. This switch might reduce industry demand for CFCs by 30 percent.
The aggregate derived demand schedule for CFCs is obtained by summing the
individual derived demand schedules of all CFC-using industries. Thus, the
aggregate demand curve represents an ordering of all options that could be taken
to decrease the use of CFCs. These steps are ordered from least costly to most
costly as seen by the participants in the CFC markets.
-------
5-6
EXHIBIT 5-1
CHANGES IN CONSUMER AND PRODUCER SURPLUS
DUE TO AN INCREASE IN CFG FRIGE
Price of
CFC in
Year t
P(0)
qd)
q(0)
s(0)
d(0)
Quantity of
CFC in Ytar t
-------
5-7
Supply of CFCs
The supply of CFCs is more difficult to characterize. If the industry were
competitive, this curve would reflect the marginal cost of CFC production at any
particular output level. Unfortunately, there are almost no data concerning the
marginal costs of production of CFCs. Moreover, data suitable for econometric
estimation of CFC supply schedules are unavailable.
The nature of modern chemical manufacture makes it reasonable to assume that
marginal costs of production of CFCs are constant over current levels of
production. However, even if such an assumption is reasonable at moderate
levels of CFC reduction, this assumption is certainly unreasonable over the
entire range of CFC production. Unfortunately, this analysis is constrained by
the lack of quantitative knowledge about the nature of CFC production and
assumes that the supply curve is horizontal ("perfectly elastic") over all
relevant CFC production levels.
The analysis recognizes that the domestic CFC industry is highly
concentrated and that it is possible that CFC prices do exceed their marginal
costs. The implications of this possibility for the estimation of the costs of
CFC regulation are explained in the next section.
Estimating Costs
The costs of CFC regulation are determined by examining the changes -- both
in price and in quantity -- occurring due to regulation in the CFC market.
Exhibit 5-1 illustrates the method. The result of CFC regulation would be a
decrease in CFC supply and an increase in CFC price. It is immaterial to the
cost estimates whether this is accomplished through a fee system that drives up
CFC prices from p(0) to p(l) and then induces quantity reductions by CFC users
or through a quota or auction that reduces CFC production from q(0) to q(l) and
induces higher prices for CFCs.
The total consumer surplus created from the consumption of CFCs is the area
below the demand curve for CFCs and above the market price of CFCs. Thus, the
decrease in consumer surplus caused by regulation is measured as the sum of
areas T and D in Exhibit 5-1. The relevant economic cost of CFC regulation is
area D. This area represents the loss in economic welfare to society through
reduced consumption of CFCs.
The other part of the reduction in consumer surplus, area T, represents a
transfer in income from consumers of CFC-using products to other segments of
society. Although this area does represent a decrease in the utility that
society derives from the consumption of CFCs and CFC-using products, it is
offset by an increase in utility that society may derive from the consumption of
substitute chemicals and other products.
As mentioned above, the analysis assumes the supply of CFCs to be horizontal
("perfectly elastic") over the entire range of production. This assumption is
equivalent to assuming that no producer surplus exists in CFC manufacture and
therefore underestimates decreases in producer surplus earned by the CFC
industry as CFC production levels decrease. This implies that the cost
estimates presented in the next section are also underestimated.
-------
5-8
As a final step in constructing the cost estimates, this methodology is
repeated annually throughout the analysis period beginning in 1989 (when costs
are first incurred due to a freeze on CFC usage at 1986 levels). Consideration
of the impact of time is essential because manufacturers will possess
considerably more opportunities to substitute new production technologies for
old ones as time progresses. Similarly, the passage of time will allow
substitute products to penetrate markets now dominated by CFC-based products.
To reflect the expected availability of new methods of reducing CFC use, the
engineering analyses identified potential technologies that may be available
over the next ten years. One example of this type of emerging technology is the
development of new chemicals, such as FC-134a or HCFC-123. As a result of the
creation of additional substitution possibilities, the demand curve for CFCs
becomes less steeply sloped ("more elastic") and the cost of achieving any
specified level of CFC reduction should decrease over time. It is likely,
moreover, that as CFC prices rise due to regulation, unforeseen opportunities
will develop, particularly over the very long time horizon of this analysis.
Consequently, long-term costs are likely to be overestimated.
A major difficulty encountered in performing the cost analysis was the
construction of a set of assumptions concerning those control options that were
not only technically feasible, but also likely actually to occur. The extensive
engineering analyses described in EPA's RIA provided substantial information
about the technologies that would be available for reducing the use of CFCs over
the foreseeable future. Each technology was characterized according to:
o the date it was expected to become available;
o the reduction in CFC use potentially achievable;
o the length of time it would take to penetrate the market;
and
o cost.
A major task of the economic analysis is to convert these characterizations of
the technological base into derived demand curves usable for economic analysis.
The cost analysis implicitly accepts a number of assumptions about human
behavior that are probably inaccurate, at least in the short run. In
particular, structurally the analysis assumes that each technology is directly
converted into practical use at the first time it is available, which requires
that producers of CFC-using products:
o possess perfect information about all available
technologies;
o always act to minimize the costs of production;
o face no costs of switching technologies beyond those
measurable in dollars due to the purchase of additional
equipment and training; and
o have unobstructed access to capital markets.
-------
5-9
Reality, as we know, is considerably different from this "idealized" view of
the world. In practice, producers of CFC-using products:
o may not learn about a technology for quite some time after
its availability;
o may not have to minimize production costs because costs
can be passed on to consumers of their products;
o face a number of "hidden costs," such as difficulties in
changing prevailing work practices, acquiring knowledge of
how to implement the new technology, or reluctance to
alter established manufacturing practices; and
o may not be able to finance a switch to a new technology
even if such an investment is profitable.
To capture some of the likely "stickiness" in conversion from one set of
manufacturing technologies to another, a number of simulations were performed.
The first simulation, labelled "least cost", assumes the availability and
penetration rates of all new technologies as described in the engineering
analyses presented in EPA's RIA (EPA, 1987b). Three other simulations, labelled
"moderate stretchout," "moderate to major stretchout," and "major stretchout"
reduce the pace at which switches to these new technologies occur. The cost
estimates that follow show cost results under each simulation.
COST RESULTS
This section describes the results of the cost analysis for alternative
levels of CFC control in the United States. The Integrated Assessment Model
(LAM) described in EPA's recent risk assessment (EPA, 1987a) and modified to
include information about the CFC cost methodology was used to develop these
estimates.
Exhibit 5-2 shows social costs estimated for the alternative control levels
over two time periods, short term (1989-2000) and longer term (1987-2075). The
costs shown in the exhibit are for the U.S. only. As shown in the exhibit,
social costs estimated for the U.S. vary with the level of required reductions.
Increasing reduction levels leads to larger U.S. costs.
Through the year 2000, the various control levels impose substantial costs
on the United States. Not only may transfer payments be substantial, but
significant capital outlays are required, for which payback will take five to
twenty years. In the first year of the freeze, on the order of $100 million in
capital investment is simulated to be required, the majority being associated
with solvent applications. Social costs are reported as small, however, because
reduced operating expenses are expected to offset these capital outlays.
-------
5-10
EXHIBIT 5-2
SOCIAL COST ESTIMATES FOR ALTERNATIVE
LEVELS OF CFC CONTROL a/
(Billions of 1985 U.S. dollars)
EIS
Alternative
Least
Cost
Moderate
Stretchouts
Moderate/
Major
Major
Short Term (1989-2000)
.2.
3.
5.
6.
7.
Long
2.
3.
5.
6.
7.
Protocol
Protocol/U.S. 80% ^/
Freeze
20% Reduction
85% Reduction^/
Term (1989-2075)
Protocol
Protocol/U.S. 80%
Freeze
20% Reduction
85% Reduction^
689
689
0
248
2,837
27 , 040
33,950
6,778
12,070
42 , 340
1,146
1,146
0
316
4,774
29,220
44,410
7,050
16,590
69,040
1,628
1,628
24
890
6,609
37,910
57,350
17,220
27,230
85,520
1,850
1,850
70
1,146
8,814
38,140
57,960
17 , 240
27,460
88,590
a/ Social costs discounted at a rate of 2 percent.
^/ The costs are equal through 2000 for Protocol and Protocol/U.S. 80% because
the 80% Reduction does not occur until after 2000.
£/ For this control level, the maximum allowable increase in CFC prices was
constrained at 50 dollars. This limit was reached in all four cost
simulations for the 85 percent reduction level.
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5-11
In the short term the social costs of alternative regulatory options vary
greatly according to assumptions about the pace at which technologies are
adopted. For example, the costs of a phased reduction in CFG use to 50 percent
combined with a freeze on halons is estimated to vary from $689 million (in 1985
dollars) under the most optimistic least cost assumptions to nearly $2 billion
if major stretchouts in technology adoption occur. Similar variations are
observed for the other alternatives.
In the long term, costs are slightly less sensitive to the pace at which
technology is adopted. Costs in the major stretchout simulation, the most
pessimistic case, are two and one-half times greater than the costs in the least
cost case for the Global Freeze. However, the percentage difference in costs is
only about 40 percent for the alternatives in which CFCs are reduced to 50
percent of the 1986 usage levels. Costs are higher in the more pessimistic
cases because, by assumption, fewer control options are available and those that
are available take longer to penetrate the market.
Over the longer term the social costs vary greatly according to the
stringency at which CFCs and halons are controlled. For example, using the
least cost simulation, costs vary from only $7 billion if CFC use is frozen at
1986 levels to nearly $43 billion if. CFC use is reduced 85 percent. Combining
lengthy stretchouts of available technologies with large restrictions in CFC use
is particularly expensive -- resulting in costs in excess of $80 billion.
Exhibit 5-3 shows the results of further sensitivity analyses examining the
implications of alternative assumptions about how CFC users might react to
increases in CFC prices. In a first simulation (the "One Year Delay" case), it
is assumed that adoption of all technologies for reducing the use of CFCs occurs
at the same rate as specified in the moderate stretchout case, but that all
changes are delayed by one year. Results of this simulation are very close to
those of the moderate stretchout simulation.
In a second simulation (the "Hidden Cost" case), it was assumed that all CFC
users face some "hidden costs" to adopting a CFC-reducing technology. These
hidden costs could be the need to amortize the cost of capital equipment just
recently purchased or a simple reluctance to adopt new methods. In this
simulation, all CFC-reduction options were assumed to cost at least $0.10 per
kilogram. Again, the results of this simulation are similar to the moderate
stretchout case.
COMPARISON OF COSTS AND HEALTH AND ENVIRONMENTAL EFFECTS
This section integrates the analysis of social costs presented in this
chapter with estimates of health and environmental consequences described in
Chapter 4.
The control alternatives that require actual reductions in CFC and halon use
significantly reduce the extent of ozone depletion, i.e., increase the amount of
stratospheric ozone available to block harmful ultraviolet radiation. The
reduction in ultraviolet radiation reaching the earth's surface decreases the
incidence of both melanoma and nonmelanoma skin cancers in the U.S. population.
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5-12
EXHIBIT 5-3
SOCIAL COST ESTIMATES FOR THE PROTOCOL ALTERNATIVE
AND THREE SETS OF COST ASSUMPTIONS^
(Present values in millions of 1985 dollars)
Social Costs b/
1989-2000
1989-2075
Moderate
Stretchout
1,146
29,220
One Year
Delay
1,193
29,270
Hidden
Cost
1,248
29,970
™ Assumes U.S ratification and implementation of the Protocol.
The Alternative assumes that CFCs are regulated with an initial
freeze in 1990 at 1986 levels, 20 percent reduction in 1994, and
50 percent reduction in 1999, and halons frozen at 1986 levels
in 1992.
Social costs are discounted at a rate of 2 percent.
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5-13
As shown in Exhibit 5-4, the number of skin cancer cases likely to occur in
people born before 2075 due to ozone depletion would be reduced by an estimated
63 to 154 million cases depending upon the levels of reductions that are
implemented worldwide. These avoided cases would have resulted in between 1.3.
and 3.2 million deaths among that same population.
The magnitude of the costs associated with each control alternative is more
sensitive to the extent to which CFC and halon use is restricted than is the
number of skin cancer cases. Thus, the deaths avoided in the Protocol
alternative are only 8 percent more than in the Freeze alternative, but the
costs of the more stringent alternative "are nearly 300 percent higher. Costs of
relatively mild restrictions on CFC use are low because a number of inexpensive
substitutes for CFCs and CFC-based products are available to achieve small
reductions in CFC emissions.
Despite this difference in sensitivity, the number of deaths avoided are
large enough that the cost of saving additional lives in the Protocol
alternative is estimated to be only $88,000 per life. Similar low costs per
life saved exist for the other alternative implementations.
HEAT.TH SAFETY, AND ENERGY IMPLICATIONS OF CHEMICAL SUBSTITUTION
One action that may be taken by consumers of CFCs in response to a
government-imposed restriction is substituting alternative chemicals for CFC
compounds. EPA's regulatory investigations have identified numerous potential
substitutes in a wide variety of applications, including such chemicals as FC-
134a and HCFC-22. The possibility exists, however, that the adoption of
chemical substitutes will itself introduce new health, safety, and environmental
risks. Some chemical substitutes, for example, are believed themselves to
deplete stratospheric ozone (e.g., HCFC-22).
Studies have been performed regarding the risks to human health and the
environment posed by the chemicals that are potential substitutes for CFCs.
Information about newer and as yet uncertain substitutes such as FC-134a is
limited, however, because toxicity testing is incomplete. The results of risk
analyses for potential CFC substitutes have recently been summarized by E.
Clarence-Smith (1986) and Dupont (1986).
Although no quantitative estimates of the risks posed by regulation-induced
chemical substitution exist, in analyzing the substitutions likely to be
implemented by industry, estimates of the extent to which chemical substitutes
may be used considered risk factors where possible. Wherever relevant, the cost
estimates include the capital and operating expenses required to meet current
environmental and safety restrictions.
The responses of CFC-consuming industries to alternative implementations of
the Montreal Protocol in the U.S. also may lead to changes in the use of energy
for these industries. EPA's analysis explicitly includes changes in energy
consumption and costs as a cost to society.
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5-14
EXHIBIT 5-4
SUMMARY OF SOCIAL COSTS AND MAJOR
BENEFITS IN THE U.S. OF EIS AT.TEBNAT-iVKS
For U.S.
Population Born Before 2075 '•
Avoided Deaths U.S. Control
EIS Ozone Depletion Avoided Cases from Skin Costs a/
Alternative in 2075 of. Skin Cancers Cancers (Millions)
(Percent) . (Millions) (Millions) of Dollars)
2 . Protocol
3. Protocol/U.S. 80%
4. Unilateral U.S.
5 . Freeze
6. 20% Reduction
7. 85% Reduction
1.3 151
1.2 151
20.4 63
6.2 139
5.0 142
0.0 154
3.14 27,040
3.15 33,950
1.34 27,040
2.93 6,778
2.99 12,070
3 . 20 42 , 340
a/ Estimates assume a 2 percent discount rate. Assumes "Least Cost" simulations.
Costs shown for long term (1989-2075) in 1985 U.S. dollars.
Source: Exhibits 4-14, 4-15, 4-16, and 5-2.
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5-15
For each substitution possibility potentially available to industry,
changes in energy usage and costs were assessed. In addition, in certain
cases, product substitutions that replace CFC-blown insulating foams with other
insulating materials were simulated to increase energy costs in homes and
buildings. These energy costs also are included in the social cost estimates
to the extent that such product substitutions are simulated to occur.
Because the reduced insulating abilities of some product substitutes
increases the projected costs of energy throughout the lifetime of the
insulating foam by significant amounts, the costs of reducing CFC use with
these products were very high (exceeding $20 per kilogram of CFC use avoided).
Because the least expensive available control options were simulated to be
undertaken before more expensive options, in general these costly options were
not simulated to be undertaken. Therefore, the energy impacts associated with
the increased costs of CFCs needed to make insulating foams are expected to be
small in nearly all cases.
Additional energy impacts may result from increased energy requirements of
refrigeration equipment operating with substitute refrigerants. For this
analysis, the expected replacements (HCFC-123 and FC-134a) are believed to have
similar enough thermodynamic properties to existing refrigerants so that no
energy impacts will result. Because" these replacement refrigerants are not yet
available in commercial quantities, and have not been fully tested, this
conclusion is somewhat tentative.
TRADE ISSUES
One component of the Montreal Protocol's approach to limiting global
emissions of CFCs and halons is to restrict trade by countries that are not
parties to the treaty. The Protocol trade restrictions- apply to bulk
CFCs/halons, products containing CFCs/halons, and possibly products
manufactured with but not containing CFCs (such as electronic components
cleaned with CFC solvents). This section analyzes the potential impacts of
Protocol trade controls, including the likely effects on U.S. competitiveness.
The Montreal Protocol includes provisions to control trade in CFC and
halon bulk chemicals and CFC and halon end-user products. The parties agree
"to:
o ban imports of CFC and halon bulk chemicals from any state
not party to the Protocol one year after entry into force;
o ban the export by developing country parties of CFC or
halon bulk chemicals to non-party countries;
o ban imports of products containing CFCs and halons from
non-party countries based on an agreed-upon list of
products;
o determine the feasibility of banning or restricting
imports of products manufactured with, but not containing
CFCs from non-party countries; and
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5-16
o discourage exports to non-party countries of technologies
for producing or using CFCs and halons.
In addition, bulk exports to other parties may be subtracted from a party's
consumption calculation, but beginning in 1993, exports to non-parties may not
be subtracted.
The goals of these provisions are to ensure free trade among parties and to
impose trade restrictions on non-parties, with the ultimate aim of protecting
the environment and creating incentives for non-parties to join.
Prices of CFCs and halons in the United States (and other Protocol
countries) can be expected to increase under the Protocol. This will occur,
largely, because of the restricted supply from Protocol limits on CFC and halon
production and trade. However, CFC and halon prices should not increase in
countries that do not join the Protocol and have their own domestic production,
or have access to CFCs and halons produced in other non-party countries.
It is theoretically possible that a disparity in CFC and halon.prices
between the U.S. and non-party countries could result in relatively higher
costs of U.S. made products related to CFCs or halons. As a consequence, U.S.
industries could become less competitive in the U.S. and international markets.
U.S. exports of CFC and halon end-user products could decline while
like-product imports could increase from non-party countries until imports are
restricted under the Protocol or domestic regulation. Transnational corporate
producers of CFC-related products might consider increasing production in
non-Protocol countries for export to the United States. Exhibit 5-5 summarizes
the effects that the Protocol may have on the international trade positions of
CFC-related products and market participants.
The actual consequences of the Protocol for the international
competitiveness of U.S. CFC and halon producers and end-user industries will
depend on at least four factors:
o the portion of product costs associated with CFCs and
halons;
o which countries join the Protocol;
o the extent to which prices for CFCs and halons and related
products increase in party compared to non-party
countries; and
o the existence of trade restrictions on CFC and halon bulk
chemicals and end-user products between Protocol party and
non-party countries.
Assessing the importance of these factors requires developing detailed data
regarding trade in relevant products as well as a method of predicting the
behavior of other governments. Unfortunately, accurate data have not been
compiled on trade of CFC and halon bulk chemicals as tariff schedules of most
countries, including the United States, do not include specific breakouts for
the various CFCs and halons. It appears, however, that the U.S. is a net
importer of CFC bulk chemicals, with imports accounting for between 5 percent
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5-17
and 10 percent of domestic U.S. CFC and halon use.
Accurate data on trade of most major CFC and halon end-user products are
available. U.S. trade in CFC end-user products is more economically important
than trade in CFC bulk chemicals. U.S. imports of products that contain CFCs
include automobiles, refrigerators, air conditioners and other products.
Electronics components and consumer goods are examples of U.S. imported
products made with but not containing CFCs.
Much uncertainty exists concerning which countries will decide to join the
Protocol. However, based on the list of- signatories, it appears that the major
trading partners of the U.S. are likely to become parties to the Protocol. The
incentive for countries to join the Protocol will vary depending upon levels of
industrial development, dependence on trade, and the political will to protect
the global environment. Those countries with export-led development strategies
and large existing or potential levels of CFC product exports will have a
strong incentive to join the Protocol. Countries in which CFCs and related
products play a small or insignificant economic role will not have a
substantial incentive to join, but may join for environmental or political
reasons.
The extent to which trade in CFC-consuming products will be affected will
depend primarily on the magnitude of CFC price increases, the amount of CFCs
used in the product's manufacture, and the decisions of other governments to
implement the Protocol. EPA's engineering analyses indicate that with few
exceptions CFCs represent a small fraction of final product prices. Those
products that are more dependent on CFCs, such as insulating foams, are not
traded significantly. Consequently, overall impacts on U.S. competitiveness
can be expected to be small.
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5-18
EXHIBIT 5-5
Affected
Products
of Protocol
Import BSD
IMPACTS OF *tw ISGVOCQL'S inun GCHCBOL
Impacted Groups
Signatory
Countries
Non-Signatory
Countries
U.S. CFC
Producers
U.S. End-User
Producers/Importers
CFC Bulk CFC prices may increase
Chemicals slightly. CFC Imports
.decline slightly. CFC
end-user product prices
Increase marginally (e.g.
foam products).
Products Prices increase for
Containing products containing CFCs.
CFCs Small welfare loss for
consumers. Imports decline.
Domestic industry profits,
output, and euiplu/maut
increase to substitute for
imports in these products.
Exports to non-signatories
decline as prices increase,
but may increase among
signatories.
Products Prices increase for
Manufae- products made with CFCs.
tured With Welfare loss for consumers.
CFCs Imports decline. Industry
profits, output and employ-
ment increase to substitute
for imports. Exports to
non-signatories decline,
but may increase among
signatories.
CFC export earnings decline
for producers. Little
impact for non-producers
(most). Higher CFC import
costs for non-producers.
Possible incentive to
produce CFCs for domestic
use and export to other
non-signatory.* Mild
incentive to join protocol.
Export earnings for .
automobiles, refrigeration
and like products decline.
Industry loses profits,
employment. Incentive to
adopt substitute chemicals
and applications to retain
market access in signatory
countries. Strong
incentive to join protocol.
Export earnings decline for
most electronics, furniture,
and consumer products.
Industry loses profits,
employment. Incentive to
adopt substitute chemicals
and applications to retain
market access in signatory
countries. Strongest
incentive to join protocol.
Small effect due to limited
CFC imports/exports. CFC
prices.and producer
profits increase slightly
in near term. Exports
may decline to non-
signatories due to higher
relative CFC prices vis-a-
vis non-signatory CFC
producers.
Possible small export
decline to non-signatory
producers of products made
with CFCs. Incentive to
develop substitute chemicals
for non-signatories
seeking to retain market
access to signatory markets.
Possible small CFC export
decline to non-signatory
producers of products
made with CFCs.
Incentive to develop
substitute chemicals for
non-signatories seeking
to retain market access
to signatory markets.
Higher CFC prices have
greatest impact on foam
industry. Other end-users
only marginally affected.
Incentive to develop ncm-
CFC products applications.
End-user product prices
increase. Possible small
decline in exports, but
increase in domestic
output, employment and
profits. U.S. importers
of products containing
CFCs lose inexpensive
foreign sources of supply,
profits and employment.
Product prices increase.
Domestic output, employ-
ment and profits increase.
Imports decline sharply.
U.S. importers lose
sources of supply,
profits and employment.
Impact could be significant
for U.S. importers of
electronics if current
suppliers do not join
protocol.
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5-19
REFERENCES
EPA (1987a), Assessing the Risks of Trace Gases That Can Modify the
Stratosphere. U.S. Environmental Protection Agency, Washington, D.C.
EPA (1987b), Regulatory Impact Analysis: Protection of Stratospheric Ozone.
U.S. Environmental Protection Agency, Washington, D.C.
Clarence-Smith, E. (1986), "Health, Safety, and Environmental Risks Associated
with Potential Substitutes for CFC-11, CFC-12, and CFC-113," The Bruce Company,
presented at Workshop on Demand and Control Technologies, Leesburg, Virginia,
March 1986.
Dupont (1986) "Alternatives to Fully Halogenated Chlorofluorocarbons: The
DuPont Development Program," Fluorocarbon Ozone Update. March 1987
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APPENDIX A
MONTREAL PROTOCOL ON
SUBSTANCES THAT DEPLETE THE OZONE LAYER
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United Nations Environment Programme UNEP
MONTREAL PROTOCOL ON
SUBSTANCES THAT DEPLETE THE OZONE LAYER
FIRAL ACT
1987
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MONTREAL PROTOCOL ON SUBSTANCES THAT DEPLETE THE OZONE LAYER
The Parties to this Protocol,
Parties to the Vienna Convention for the Protection of the Ozone
Mindful of their obligation under that Convention to take appropriate
measures to protect human health and the environment against adverse effects
resulting or likely to result from huma*i activities which modify or are likely
to modify the ozone layer,
Recognizing that world-wide emissions of certain substances can
significantly deplete and otherwise modify the ozone layer in a manner that is
likely to result in adverse effects on human health and the environment,
Conscious of the potential climatic effects of emissions of these
substances,
Aware that measures taken to protect the ozone layer from depletion should
be based on relevant scientific knowledge, taking into account technical and
economic considerations,
Determined to protect the ozone layer by taking precautionary measures to
control equitably total global emissions of substa-ces that deplete it, with
the ultimate objective of their elimination on thf- Dasis of developments in
scientific knowledge, taking into account technica and economic
considerations,
Acknowledging that special provision is required to meet the needs of
developing countries for these substances,
Noting the precautionary measures for controlling emissions of certain
chlorofluorocarbons that have already been taken ac national and regional
levels,
Considering the importance of promoting international co-operation in the
research and development of science and technology relating to the control and
reduction of emissions of substances that deplete the ozone layer, bearing in
mind in particular the needs of developing countries,
HAVE AGREED AS FOLLOWS:
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ARTICLE 1: DEFINITIONS
For Che purposes of this Protocol:
1. "Convention" means the Vienna Convention for the Protection of the Ozone
Layer, adopted on 22 March 1985.
2. "Parties" means, unless the text otherwise indicates, Parties to this
Protocol.
3. "Secretariat" means the secretariat of the Convention.
4. "Controlled substance" means a substance listed in Annex A to this
Protocol, whether existing alone or in a mixture. It excludes, however, any
such substance or mixture which is in a manufactured product other than a
container used for the transportation or storage of the substance listed.
5. "Production" means the amount of controlled substances produced minus the
amount destroyed by technologies to be approved by the Parties.
6. "Consumption" means production plus imports minus -xports of controlled
substances.
7. "Calculated levels" of production, imports, exports and consumption means
levels determined in accordance with Article 3.
8. "Industrial rationalization" means the transfer of all or a portion of the
calculated level of production of one Party to another, for the purpose of
achieving economic efficiencies or responding to anticipated shortfalls in
supply as a result of plant closures.
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ARTICLE 2: CONTROL MEASURES
1. Each Party shall ensure that for the twelve-month period commencing on the
first day of the seventh month following the date of the entry into force of
this Protocol, and in each twelve-month period thereafter, its calculated level
of consumption of the controlled substances in Group I of Annex A does not
exceed its calculated level of consumption in 1986. By the end of the same
period, each Party producing one or more of these substances shall ensure that
its calculated level of production of the substances does not exceed its
calculated level of production in 1986, except that such level may have
increased by no more than ten per cent based on the 1986 level. Such increase
shall be permitted only so as to satisfy the basic domestic needs of the
Parties operating under Article 5 and for the purposes of industrial
rationalization between Parties.
2. Each Party shall ensure that for the twelve-month period commencing on the
first day of the thirty-seventh month following the date of the entry into
force of this Protocol, and in each twelve month period thereafter, its
calculated level of consumption of the controlled substances listed in Group II
of Annex A does not exceed its calculated level of consumption in 1986. Each
Party producing one or more of these substances shall ensure that its
calculated level of production of the substances does not .exceed its calculated
level of production in 1986, except that such level may have increased by no
more than ten per cent based on the 1986 level. Such increase shall be
permitted only so as to satisfy the basic domestic needs of the Parties
operating under Article 5 and for the purposes of industrial rationalization
between Parties. The mechanisms for implementing these measures shall be
decided by the Parties at their first -meeting fol'^wing the first scientific
review.
3. Each Party shall ensure that for the period . July 1993 to 30 June 1994
and in each twelve-month period thereafter, its c Lculated level of consumption
of the controlled substances in Group I of Annex A does not exceed, annually,
eighty per cent of its calculated level of consumption in 1986. Each Party
producing one or more of these substances shall, for the same periods, ensure
that its calculated level of production of the substances does not exceed,
annually, eighty per cent of its calculated level of production in 1986.
However, in order to satisfy the basic domestic needs of the Parties operating
under Article 5 and for the purposes of industrial rationalization between
Parties, its calculated level of production may exceed that limit by up to ten
per cent of its calculated level of production in 1986.
4. Each Party shall ensure that for the period 1 July 1998 to 30 June 1999,
and in each twelve-month period thereafter, its calculated level of consumption
of the controlled substances in Group I of Annex A does noc exceed, annually,
fifty per cent of its calculated level of consumption in 1986. Each Party
producing one or more of these substances shall, for the same periods, ensure
that its calculated level of production of the substances does not exceed,
annually, fifty per cent of its calculated level of production in 1986.
However, in order to satisfy the basic domestic needs of the Parties operating
under Article 5 and for the purposes of industrial rationalization between
Parties, its calculated level of production may exceed that limit by up to
fifteen per cent of its calculated level of production in 1986. This
-------
paragraph will apply unless the Parties decide otherwise at a meeting by a
two-thirds majority of Parties present and voting, representing at least
two-thirds of the total calculated level of consumption of these substances of
the Parties. This decision shall be considered and made in the light of the
assessments referred to in Article 6.
5. Any Party whose calculated level of production in 1986 of the controlled
substances in Group I of Annex A was less than twenty-five kilotonnes may, for
the purposes of industrial rationalization, transfer to or receive from any
other Party, production in excess of the limits set out in paragraphs 1, 3 and
4 provided that the total combined calculated levels of production of the
Parties concerned does not exceed the production limits set out in this
Article. Any transfer of such production -shall be notified to the secretariat,
no later than the time of the transfer.
6. Any Party not operating under Article 5, that has facilities for the
production of controlled substances under construction, or contracted for,
prior to 16 September 1987, and provided for in national legislation prior to
1 January 1987, may add the production from such facilities to its 1986
production of such substances for the purposes of determining its calculated
level of production for 1986, provided that such facilities are completed by
31 December 1990 and that such production does not raise that Party's annual
calculated level of consumption of the controlled substances above 0.5
kilograms per capita.
7. Any transfer of production pursuant to paragraph 5 or any addition of
production pursuant to paragraph 6 shall be notified to the secretariat, no
later than the time of the transfer or addition.
8. (a) Any Parties which are Member States of a r gional economic
integration organization as defined in Art.:le 1(6) of the
Convention may agree that they shall joint'./ fulfil their
obligations respecting consumption under this Article provided that
their total combined calculated level of consumption does not exceed
the levels required by this Article.
(b) The Parties to any such agreement shall inform the secretariat of
the terms of the agreement before the date of the reduction in
consumption with which the agreement is concerned.
(c) Such agreement will become operative only if all Member States of
the regional economic integration organization and the organization
concerned are Parties to the Protocol and have notified the
secretariat of their manner of implementation.
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9. (a) Based on the assessments made pursuant to Article 6, the Parties may
decide whether:
(i) adjustments to the ozone depleting potentials specified in
Annex A should be made and, if so, what the adjustments should
be; and
«
(ii) further adjustments and reductions of production or consumption
of the controlled substances from 1986 levels should be
undertaken and, if so, what the scope, amount and timing of any
such adjustments and reductions should be.
(b) Proposals for such adjustments shall be communicated to the Parties
by the secretariat at least six months before the meeting of the
Parties at which they are proposed for adoption.
(c) In taking such decisions, the Parties shall make every effort to
reach agreement by consensus. If all efforts at consensus have been
exhausted, and no agreement reached, such decisions shall, as a last
resort, be adopted by a two-thirds majority vote of the Parties
present and voting representing at least fifty per cent of the total
consumption of the controlled substances of the Parties.
(d) The decisions, which shall be binding on all Parties, shall forthwith
be communicated to the Parties by the Depositary. Unless otherwise
provided in the decisions, they shall enter into force on the expiry
of six months from the date of the circulation of the ujtnmunication
by the Depositary.
10. (a) Based on the assessments made pursuant : Article 6 of this Protocol
and in accordance with the procedure se- out in Article 9 of the
Convention, the Parties may decide:
(i) whether any substances, and if so which, should be added to or
removed from any annex to this Protocol; and
(ii) the mechanism, scope and timing of the control measures that
should apply to those substances;
(b) Any such decision shall become effective, provided that it has been
accepted by a two-thirds majority vote of the Parties present and
voting.
11. Notwithstanding the provisions contained in this Article, Parties may take
more stringent measures than those required by this Article.
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ARTICLE 3: CALCULATION OF CONTROL LEVELS
For the purposes of Articles 2 and 5, each Party shall, for each Group of
substances in Annex A, determine its calculated levels of:
.(a) production by:
(i) multiplying its annual production of each controlled substance
by the ozone depleting potential specified in respect of it in
Annex A; and
(ii) adding together, for each such Group, the resulting figures;
(b) imports and exports, respectively, by following, mutatis mutandis,
the procedure set out in subparagraph (a); and
(c) consumption by adding together its calculated levels of production
and imports and subtracting its calculated level of exports as
determined in accordance with subparagraphs (a) and (b). However,
beginning on 1 January 1993, any export of controlled substances to
non-Parties shall not be subtracted in calculating the consumption
level of the exporting Party.
ARTICLE 4: CONTROL OF TRADE WITH NON-PARTIES
1. Within one year of the entry into force of this Protocol, each Party shall
ban the import of controlled substances from any State not party to this
Protocol.
2. Beginning on 1 January 1993, no Party operating un:-;r paragraph 1 of
Article 5 may export any controlled substance to any Scite not party to this
Protocol.
3. Within three years of the date of the entry into force of this Protocol,
the Parties shall, following the procedures in Article 10 of the Convention,
elaborate in an annex a list of products containing controlled substances.
Parties that have not objected to the annex in accordance with those procedures
shall ban, within one year of the annex having become effective, the import of
those products from any State not party to this Protocol.
4. Within five years of the entry into force of this Protocol, the Parties
shall determine the feasibility of banning or restricting, from States not
party to this Protocol, the import of products produced with, but not
containing, controlled substances. If determined feasible, the Parties shall,
following the procedures in Article 10 of the Convention, elaborate in an annex
a list of such products. Parties that have not objected to it in accordance
with those procedures shall ban or restrict, within one year of the annex
having become effective, the import of those products from any State not party
to this Protocol.
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5. Each Party shall discourage the export, to any State not party to this
Protocol, of technology for producing and for utilizing controlled substances.
6. Each Party shall refrain from providing new subsidies, aid, credits,
guarantees or insurance programmes for the export to States not party to this
Protocol of products, equipment, plants or technology that would facilitate the
production of controlled substances.
7. Paragraphs 5 and 6 shall not apply to products, equipment, plants or
technology that improve the containment, recovery, recycling or destruction of
controlled substances, promote the development of alternative substances, or
otherwise contribute to the reduction of emissions of controlled substances.
8. Notwithstanding the provisions of this Article, imports referred to in
paragraphs 1, 3 and 4 may be permitted from any State not party to this
Protocol if that State is determined, by a meeting of the Parties, to be in
full compliance with Article 2 and this Article, and has submitted data to that
effect as specified in Article 7.
ARTICLE 5: SPECIAL SITUATION OF DEVELOPING COUNTRIES
1. Any Party that is a developing country and whose annual calculated level of
consumption of the controlled substances is less than 0.3 kilograms per capita
on the date of the entry into force of the Protocol for it, or any time
thereafter within ten years ot the date of entry i-to force of the Protocol
shall, in order to meet its basic domestic needs,' •? entitled to delay its
compliance with the control measures set cut in paragraphs 1 to 4 of Article 2
by ten years after that specified in those paragra-hs. However, such Party
shall not exceed an annual calculated level of consumption of 0.3 kilograms per
capita. Any such Party shall be entitled to use either the average of its
annual calculated level of consumption for the period 1995 to 1997 inclusive or
a calculated level of consumption of 0.3 kilograms per capita, whichever is the
lower, as the basis for its compliance with the control measures.
2. The Parties undertake to facilitate access to environmentally safe
alternative substances and technology for Parties that are developing countries
and assist them to make expeditious use of such alternatives.
3. The Parties undertake to facilitate bilaterally or multilaterally the
provision of subsidies, aid, credits, guarantees or insurance programmes to
Parties that are developing countries for the use of alternative technology and
for substitute products.
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ARTICLE 6: ASSESSMENT AND REVIEW OF CONTROL MEASURES
Beginning in 1990, and at least every four years thereafter, the Parties
shall assess the control measures provided for in Article 2 on the basis of
available scientific, environmental, technical and economic information. At
least one year before each assessment, the. Parties shall convene appropriate
panels of experts qualified in the fields mentioned and determine the
composition and terms of reference of any such panels. Within one year of
being convened, the panels will report their conclusions, through the
secretariat, to the Parties.
ARTICLE 7: REPORTING OF DATA
1. Each Party shall provide to the secretariat, within three months of
becoming a Party, statistical data on its production, imports and exports of
each of the controlled substances for the year 1986, or the best possible
estimates of such data where actual data are not available.
2. Each Party shall provide statistical data to the secretariat on its
annual production (with separate data on amounts destroyed by technologies to
be approved by the Parties), imports, and exports to Parties and non-Parties,
respectively, of such substances for the year during which it becomes a Party
and for each year thereafter. It shall forward the data no later than nine
months after the end of the year to which th- data relate.
ARTICLE 8: NON-COMPLIANCE
The Parties, at their first meeting, shall consider and approve
procedures and institutional mechanisms for determining non-compliance with the
provisions of this Protocol and for treatment of Parties found to be in
non-compliance.
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ARTICLE 9: RESEARCH, DEVELOPMENT, PUBLIC AWARENESS
AND EXCHANGE OF INFORMATION
1. The Parties shall co-operate, consistent with their national lavs,
regulations and practices and taking into account in particular the needs of
developing countries, in promoting, directly or through competent international
bodies, research, development and exchange of information on:
(a) best technologies for improving the containment, recovery, recycling
or destruction of controlled substances or otherwise reducing their
emissions;
(b) possible alternatives to controlled substances, to products
containing such substances, and to products manufactured with them;
and
(c) costs .and benefits of relevant control strategies.
2. The Parties, individually, jointly or through competent international
bodies, shall co-operate in promoting public awareness of the environmental
effects of the emissions of controlled substances and other substances that
deplete the ozone layer.
3. Within two years of the entry into force of this Protocol and every two
years thereafter, each Party shall submit to the secretariat a summary of the
activities it has conducted pursuant to this Article.
ARTICLE 10: TECHNICAL ASS:STANCE
1. The Parties shall, in the context of the provisions of Article 4 of the
Convention, and taking into account in particular the needs of developing
countries, co-operate in promoting technical assistance to facilitate
participation in and implementation of this Protocol.
2. Any Party or Signatory to this Protocol may submit a request to the
secretariat for technical assistance for the purposes of implementing or
participating in the Protocol.
3. The Parties, at their first meeting, shall begin deliberations on the means
of fulfilling the obligations set out in Article 9, and paragraphs 1 and 2 of
this Article, including the preparation of workplans. Such vorkplans shall pay
special attention to the needs and circumstances of the developing countries.
States and regional economic integration organizations not party to the
Protocol should be encouraged to participate in activities specified in such
workplans.
-------
ARTICLE 11: MEETINGS OF THE PARTIES
1. The Parties shall hold meetings at regular intervals. The secretariat
shall convene the first meeting of the Parties not later than one year after
the date of the entry into force of this Protocol and in conjunction with a
meeting of the Conference of the Parties to the Convention, if a meeting of the
latter is scheduled within that period.
2. Subsequent ordinary meetings of the Parties shall be held, unless the
Parties otherwise decide, in conjunction with meetings of the Conference of the
Parties to the Convention. Extraordinary meetings of the Parties shall be held
at such other times as may be deemed necessary by a meeting of the Parties, or
at the written request of any Party, provided that, within six months of such a
request being communicated to them by the secretariat, it is supported by at
least one third of the Parties.
3. The Parties, at their first meeting, shall:
(a) adopt by consensus rules of procedure for their meetings;
(b) adopt by consensus the financial rules referred to in paragraph 2 of
Article 13; • -
(c) establish the panels and determine the terms of reference referred to
in Article 6;
(d) consider and approve the procedures and institutional mechanisms
specified in Article 8; and
(e) begin preparation of workplans pursuant to paragraph 3 of Article 10.
4. The functions of the meetings of the Parties shall be to:
(a) review the implementation of this Protocol;
(b) decide on any adjustments or reductions referred to in paragraph 9
of Article 2;
(c) decide on any addition to, insertion in or removal from any annex of
substances and on related control measures in accordance with
paragraph 10 of Article 2;
10
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(d) establish, where necessary, guidelines or procedures for reporting of
information as provided for in Article 7 and paragraph 3 of
Article 9;
(e) review requests for technical assistance submitted pursuant to
paragraph 2 of Article 10;
(f) review reports prepared by the secretariat pursuant to sub-
paragraph (c) of Article 12;
(g) assess, in accordance with Article 6, the control measures provided
for in Article 2;
y(h) consider and adopt, as required, proposals for amendment of this
Protocol or any annex and for any new annex;
(i) consider and adopt the budget for implementing this Protocol; and
(j) consider and undertake any additional action that may be required for
the achievement of the purposes of this Protocol.
5. The United Nations, its specialized agencies and the International Atomic
Energy Agency, as well as any State not party to this Protocol, may be
represented at meetings of the Parties as observers. Any body or agency,
whether national or international, governmental or non-governmental, qualified
in fields relating to the protection of the ozone layer which has informed the
secretariat of its wish to be represented at a meeting of the Parties as an
observer may be admitted unless at least one third of the Parties present
object-. The admission and participation of observ rs shall be subject to the
rules of procedure adopted by the Parties.
ARTICLE 12: SECRETARIAT
For the purposes of this Protocol, the secretariat shall:
(a) arrange for and service meetings of the Parties as provided for in
Article 11;
(b) receive and make available, upon request by a Party, data provided
pursuant to Article 7;
(c) prepare and distribute regularly to the Parties reports based on
information received pursuant to Articles 7 and 9;
11
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(d) notify the Parties of any request for technical assistance received
pursuant to Article 10 so as to facilitate the provision of such
assistance;
(e) encourage non-Parties to attend the meetings of the Parties as
observers and to act in accordance with the provisions of this
Protocol;
(f) provide, as appropriate, the information and requests referred to in
subparagraphs (c) and (d) to such non-party observers; and
(g) perform such other functions for the achievement of the purposes of
this Protocol as may be assigned to it by the Parties.
ARTICLE 13: FINANCIAL PROVISIONS
1. The funds required for the operation of this Protocol, including those for
the functioning of the secretariat related to this Protocol, shall be charged
exclusively against contributions from the Parties.
2. The Parties, at their first meeting, shall adopt by consensus financial
rules for the operation of this Protocol.
ARTICLE 14: RELATIONSHIP OF THIS PROTOCOL TO THE CONVENTION
Except as otherwise provided in this Protocol, the provisions of the
Convention relating to its protocols shall apply to this Protocol.
ARTICLE 15: SIGNATURE
This Protocol shall be open for signature by States and by regional
economic integration organizations in Montreal on 16 September 1987, in Ottawa
from 17 September 1987 to 16 January 1988, and at United Nations Headquarters
in New York from 17 January 1988 to 15 September 1988.
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ARTICLE 16: ENTRY INTO FORCE
1. This Protocol shall enter into force on 1 January 1989, provided that at
least eleven instruments of ratification, acceptance, approval of the Protocol
or accession thereto have been deposited by States or regional economic
integration organizations representing at least two-thirds of 1986 estimated
global consumption of the controlled substances, and the provisions of
paragraph.1 of Article 17 of the Convention have been fulfilled. In the event
that these conditions have not been fulfilled by that date, the Protocol shall
enter into force on the ninetieth day following the date on which the
conditions have been fulfilled.
2. For the purposes of paragraph 1, any such instrument deposited by a
regional economic integration organization shall not be counted as additional
to those deposited by member States of such organization.
3. After the entry into force of this Protocol, any State or regional economic
integration organization shall become a Party to it on the ninetieth day
following the date of deposit of its instrument of ratification, acceptance,
approval or accession.
ARTICLE 17: PARTIES'JOINING AFTER ENTRY INTO FORCE
Subject to Article 5, any State or regional economic integration
organization which becomes a Party to this Protocol after the date of its entry
into force, shall fulfil forthwith the sum of the obligations under Article 2,
as well as under Article 4, that apply at that da ? to the States and regional
C'conomic integration organizations that became Farcies on the date the Protocol
entered into force.
ARTICLE 18: RESERVATIONS
No reservations may be made to this Protocol.
ARTICLE 19: WITHDRAWAL
For the purposes of this Protocol, the provisions of Article 19 of the
Convention relating to withdrawal shall apply, except with respect to Parties
referred to in paragraph 1 of Article 5. Any such Party may withdraw from this
Protocol by giving written notification to the Depositary at any time after
four years of assuming the obligations specified in paragraphs 1 to 4 of
Article 2. Any such withdrawal shall take effect upon expiry of one year after
the date of its receipt by the Depositary, or on such later date as may be
specified in the notification of the withdrawal.
13
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ARTICLE 20: AUTHENTIC TEXTS
The original of this Protocol, of which the Arabic, Chinese, English,
French, Russian and Spanish texts are equally authentic, shall be deposited
with the Secretary-General of the United Nations.
IN WITNESS WHEREOF THE UNDERSIGNED, BEING DULY AUTHORIZED TO THAT EFFECT,
HAVE SIGNED THIS PROTOCOL.
DONE AT MONTREAL THIS SIXTEENTH DAY OF SEPTEMBER, ONE THOUSAND NINE
HUNDRED AND EIGHTY SEVEN
14
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ANNEX A
CONTROLLED SUBSTANCES
Group Substance Ozone Depleting
Potential *
Group I
CFC13 (CFC-11) 1.0
CF2C12 (CFC-12) 1.0
C2F3C13 (CFC-113) 0.8
C2F4C12 (CFC-11A) " 1.0
C2F5C1 (CFC-115) 0.6
Group II
CF2BrC'l (halon-1211) 3.0
CF3Br (halon-1301) ' 10.0
C2F4&r2 (halon-2402) (to be determined)
* These ozone-depleting potentials are estimates based on existing
knowledge and will be reviewed and revised periodically.
15
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APPENDIX B
EXECUTIVE SUMMARY OF
U.S. EPA, ASSESSING THE RISKS OF
TRACE GASES THAT CAN MODIFY THE
STRATOSPHERE (1987) (EPA'S RISK ASSESSMENT)
-------
ASSESSING THE RISKS OF TRACE GASES
THAT CAN MODIFY THE STRATOSPHERE
VOLUME I: EXECUTIVE SUMMARY
BY
OFFICE OF AIR AND RADIATION
U.S. ENVIRONMENTAL PROTECTION AGENCY
401 M STREET, S.U.
WASHINGTON, D.C. 20460
p
DECEMBER 1987
-------
ASSESSING THE RISKS OF TRACE GASES
THAT CAN MODIFY THE STRATOSPHERE
VOLUME I: EXECUTIVE SUMMARY
SENIOR EDITOR AND AUTHOR: JOHN S. HOFFMAN
CONTRIBUTORS: CRAIG EBERT?, SARAH FOSTER?,
MICHAEL J. GIBBS?,
KEVIN HEARLE2, BRIAN HICKS?,
PATSY H. LILL^, JANICE LONGSTRETH^,
NEIL PATEL*, HUGH M. PITCHER!,
ALAN F. TERAMURA^, DENNIS TIRPAK*,
JOHN B. WELLS6, G. Z. WHITTEN?,
ROBERT WORREST^
1 U.S. ENVIRONMENTAL PROTECTION AGENCY, 401 M STREET, S.W.,
WASHINGTON, DC
? ICF INCORPORATED, 9300 LEE HIGHWAY, FAIRFAX, VA
3 UNIVERSITY OF SOUTH CAROLINA SCHOOL OF MEDICINE, COLUMBIA,
SC
4 ICF-CLEMENT, 9300 LEE HIGHWAY, FAIRFAX, VA
5 DEPARTMENT OF BOTANY, UNIVERSITY OF MARYLAND, COLLEGE PARK,
MD
6 THE BRUCE COMPANY, SUITE 410, 3701 MASSACHUSETTS AVE., N.W.,
WASHINGTON, DC
7 SYSTEMS APPLICATIONS, INC., 101 LUCAS VALLEY ROAD, SAN
RAFAEL, CA
8 CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY, 200 SOUTHWEST
35TH STREET, CORVALLIS, OR
DECEMBER 19S7
-------
ACKNOWLEDGEMENTS
Many'people made this document possible.
A Science Advisory Board panel chaired by Dr. Margaret Kripke and co-
chaired by Dr. Warner North conducted an extensive and constructive review of
this document. Members of the panel provided important insights and assistance
in the assessments development. Members of the panel are:
Dr. Martyn Caldwell (Utah State University)
Dr. Leo T. Chylack, Jr. (Center for Clinical Cataract Research)
Dr. Nien Dak Sze (A.E.R., Inc.)
Dr. Robert Dean
Dr. Thomas Fitzpatrick (Massachusetts General Hospital)
Dr. James Friend (Drexel University)
Dr. Donald Hunten (University of Arizona)
Dr. Warren Johnson (National Center for Atmospheric Research).
Dr. Margaret Kripke (Anderson Hospital and Tumor Institute)
Dr. Lester Lave (Carnegie-Melon University)
Dr. Irving Mintzer (World Resources Institute)
Dr. Warner North (Decision Focus, Inc.)
Dr. Robert Watson (National Aeronautics and Space Administration)
Dr. Charles Yentsch (Bigelow Laboratory)
Dr. Terry F. Yosie (U.S. Environmental Protection Agency)
The panel's contribution to the process of protecting stratospheric ozone has
been critical. We also want to thank Terry Yosie, Director of the Science
Advisory Board, for setting up and helping to run the panels, and Joanna
Foellmer for helping to organize meetings.
Other scientists and analysts, too numerous to name, provided reviews of
early drafts of the chapters.
Production assistance, including editing, typing, and graphics, was
provided by the staff of ICF Incorporated, including:
Bonita Bailey
Susan MacMillan
Mary O'Connor
Maria Tikoff of the U.S. Environmental Protection Agency, coordinated
logistical parts of this document.
Technical support documents (Volumes VI, VII, and VIII) have been published
along with the first five volumes of the Risk Assessment. These documents are
not part of the official Risk Assessment, and have not been reviewed by the •
SAB. Their publication is simply to assist readers who wish more background
than available in the Risk Assessment.
-------
TABLE OF CONTENTS
PAGE
VOLUME I
ACKNOWLEDGMENTS i
ORGANIZATION ES-1 .
INTRODUCTION ES-2
SUMMARY FINDINGS ES-5
CHANGES IN ATMOSPHERIC COMPOSITION . '.'. ES-15
POTENTIAL CHANGES IN OZONE AND CLIMATE ES-23
HUMAN HEALTH, WELFARE, AND ENVIRONMENTAL EFFECTS ES-32
QUANTITATIVE ASSESSMENT OF RISKS WITH INTEGRATED MODEL ES-54
TABLE OF CONTENTS FOR FULL RISK ASSESSMENT ' ES-65 .
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ORGANIZATION
This document summarizes a multi-volume assessment of the risks of
stratospheric modification. Since the early 1970s, scientists have been
concerned that human activities could alter the composition of the stratosphere,
leading to reductions in the quantity of ozone protecting earth from the sun's
ultraviolet-B (UVB) radiation. If such reductions in ozone levels occurred,
public health and welfare would be harmed.
Substantial scientific progress has been made since concern about ozone
depletion was first raised. This document represents a synopsis of current
understanding of how atmospheric composition may change, the effects this change
is likely to have on ozone abundance and its vertical distribution, and the
impacts of these changes in ozone on skin cancer, cataracts, suppression of the
immune system, polymers, plants, and aquatic systems. It also examines related
changes in climate and the potential impacts of climate change on sea level
rise, agriculture, human health, water resources, and forests.
Despite significant improvement in our understanding of these issues,
substantial uncertainties remain. This risk assessment identifies and discusses
these uncertainties and, where possible, estimates quantitatively their
potential significance.
Following a brief introduction, this summary volume is organized into five
sections:
o Summary findings (page ES-5);
o Changes in atmospheric Composition covers chapters 2, 3, and
4 (page ES-15);
o Potential changes in ozone and climate covers chapters 5 and
6 (page ES-23);
o Human health, welfare, and environmental effects covers
chapters 7 through 16 (page ES-32); and
o Quantitative assessment of risks with integrated model covers
chapters 17 and 18 (page ES-54).
Readers desiring greater detail are encouraged to refer to the five-volume risk
assessment and the three volumes of the technical support reports.
This summary concludes with a brief listing of major prior assessments of
this issue.
-------
ES-2
INTRODUCTION
Current scientific theory and evidence indicate that continued increases in
the concentrations of a variety of trace gases in the atmosphere .are likely to .
modify the vertical distribution and column abundance of stratospheric and
tropospheric ozone. Changes in the total abundance of column ozone would alter the
flux of ultraviolet radiation reaching the surface of the earth, and consequently
affect public health and welfare. Scientific evidence indicates that increases in
ultraviolet-B radiation (UV-B) would alter skin cancer morbidity and mortality,
increase cataracts, and probably suppress the human immune system. Evidence also
supports the conclusion that such increases could reduce crop yields and alter
terrestrial and aquatic ecosystems. Scientific theory and studies also support the
conclusion that polymers would be degraded more quickly and that urban tropospheric
oxidants would increase as a result of UV-B increases, although additional
scientific study is needed to validate the possible effects on tropospheric air
quality. The dimensions of many of these risks are at this time unquantifiable.
Exhibit ES-1 summarizes these relationships.
Changes in trace gases that can modify the stratosphere can be expected to
contribute to climate change in three ways: they are all greenhouse gases that
would increase global warming; by modifying vertical distribution of ozone, they
could change the Earth's radiative balance and climate dynamics; by adding water
vapor to the stratosphere, one of these gases (methane) directly adds to the
stratosphere's greenhouse or warming capacity. The effects of global warming
include changes in weather and climate patterns; rises in sea level; changes in
forests, hydrologic processes, and agriculture; and a variety of associated
impacts.
Current science projects that changes in ozone and climate will occur slowly
enough in the next decade that it is unclear that monitoring systems will be
capable of clearly detecting change, or of attributing changes to particular trace
gas increases. Because of the large lags expected between the emission of gases
and their ultimate effect on ozone and climate, the stabilization of atmospheric
concentrations and the prevention of further change would require large decreases
in trace gas emissions. Consequently, while monitoring can provide a valuable
system to test model .projections, as well as to better understand atmospheric
systems, except in the case of a larger than expected atmospheric change,
monitoring cannot be expected to provide definitive information about the nature of
future risks. With the exception of Antarctic ozone depletion, an unexpected and,
at this time, unexplained phenomenon, past monitoring supports current models,
which project that ozone depletion and climate change are likely to occur in the
face of growth in the concentrations of trace gases. It is important to recognize
1 This Risk Assessment was written before the results of the two Antarctic
campaigns were available and has not been revised to consider them. It now appears
that the Antarctic ozone hole is at least partly caused by man-made chemicals. The
implications for ozone in the rest of the world are unclear, depending on whether
the loss mechanisms operating in Antarctica are likely to operate elsewhere and on
whether Antarctic losses themselves might have global implications. Consequently,
until those issues are resolved, we cannot conclude that the 'hole' is a portent of
things to come elsewhere on the Earth. In the rest of this summary the original
Risk Assessment findings on Antarctica and trends are kept intact.
-------
EXHIBIT ES-1
The Basis for Concern About CFCs and Ozone Depletion
( 1) Production of CFCs (9) Increases In UV-B produce effects
,«*•? • • ... For example:
(2) Emissions then occur
On skin cancer
(3) Concentrations build up
(4) Slow transport to stratosphere
(6) Photodissociatlon of CFCs
releases chlorine
(6) Chlorine catalytlcally
reduces ozone
(7) Ozone depletion causes
changes in UV-B
(8) CFCs and column reorganization
change the climate
On Larval Northern Anchovy
Larval Norlhirn Anchovy
Causal Chain:
10 20 30 40 M M
INCREASED UV-B RADIATION (XI
TO
Production ^-Emissions—^- Concen **~ Atmospheric—^" UV-B —•*- Effects
trations Response and climate
in
Source: NAS (197$). Scotto (1986). and Hunter. Kaupp ntid Taylor (1982).
-------
ES-4
that "by the time it is possible to detect decreases in ozone concentrations
with a high degree of confidence, it may be too late to institute corrective
measures that would reverse this trend" (EPA Science Advisory Board, March
1987).
-------
ES-5
SUMMARY FINDINGS
Past and Possible Future Changes in Trace Gases
1. Considerable research has taken place since 1974 when the theory linking
chlorine from chlorofluorocarbons (CFCs) and depletion of ozone was first
developed. While uncertainties remain, the evidence to date continues to
support the original theory that CFCs have the potential to decrease
stratospheric ozone.
2. Atmospheric measurements show that the chemical composition of the
atmosphere -- including gases that affect ozone -- has been changing.
Recently measured annual rates of growth in global atmospheric
concentrations of trace gases that influence ozone include: CFC-11:
5 percent; CFC-12: 5 percent; CFC-113: 10 percent; carbon tetrachloride: 1
percent; methyl chloroform: 7 percent; nitrous oxide: 0.2 percent; carbon
monoxide: 1 to 2 percent; carbon dioxide: 0.5 percent; and methane: 1
percent. More limited measurements of Halon 1211 show recent annual
increases of 23 percent in atmospheric concentrations.
3. CFCs, Halons, methyl chloroform, and carbon tetrachloride release chlorine
or bromine into the stratosphere where they act as catalysts to reduce the
net amount of ozone. In contrast, carbon dioxide and methane either add to
the total column of ozone -r slow the rate of depletion. The effect of
increases in nitrous oxide varies depending on the relative level of
chlorine.
•arr
4. CFCs, methyl chloroform, carbon tetrachloride, and Halons are industrially
produced. Emissions of methane, carbon dioxide, and nitrous oxide occur
from both human activity and the natural biosphere. Because all these gases
(with the exception of methane and methyl chloroform) remain in the
atmosphere for many decades to over a century, emissions today will
influence ozone levels for more than a century. Also, as a result of these.
long lifetimes, concentrations of these gases will rise for more than a
century, even if emissions remain at constant levels. For example, to
stabilize concentrations of CFC-11 or -12 would require a reduction in
current global emissions of about 80 percent. (Exhibit ES-2 demonstrates
effects of various reduction levels on CFC-12 concentrations).
5. In order to assess risks, scenarios of atmospheric change were evaluated
using models. For CFCs, methyl chloroform, carbon tetrachloride, and
Halons, demand for goods that contain or are manufactured with these
chemicals (e.g., refrigerators, computers, automobile air conditioners) and
the historic relationship between economic activity and the use of these
chemicals were analyzed. These analyses indicate that in the absence of
regulation, the use and emissions of these compounds are expected to
increase in the future. However, for purposes of analyzing risks, six
"what-if" scenarios were adopted that cover a greater range of future
production of ozone-depleting substance than is likely to occur.
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ES-6
EXHIBIT ES-2
CPC-12: Atmospheric Concentrations
from Different Emission Trajectories
* 2
1
§
8.
2
* 1
§
8
8
0
Constant
emissions
15% Cut
50% Cul
85% Cut
1930
1905
2100
Atmospheric concentrations of CFC-12 will continue to rise unless emissions are
cut. Holding emissions constant at today's level or even 15 percent or 50
percent lower would still allow atmospheric concentrations to grow. Only a cut
of 85 percent or more could stabilize atmospheric concentrations.
Source: Hoffman, 1986.
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ES-7
Model Projections for Ozone Changes
6. Atmospheric chemistry models were used to assess the potential effects of
possible future changes in atmospheric concentrations of trace gases. These
models attempt to simulate processes that influence the creation and
destruction of ozone. While the models replicate many of the
characteristics of the atmosphere accurately, they are inconsistent with
measured values of other constituents, thus lowering our confidence in their
ability to predict future ozone changes accurately.
7. Based on the results from these models, the cause of future changes in ozone
will be highly dependent on future emissions of trace gases.
One-dimensional models project that if the use of chlorine and bromine
containing substances remains constant globally, and other trace gas
concentrations continue to grow, total column ozone levels would at first
decrease slightly, and then would subsequently increase. If the use of CFCs
continues to grow at past rates and other gases also increase at recent
rates, substantial total column ozone depletion would occur by the middle of
the next century. If the use of CFCs stays at current levels and the growth
in the concentrations of other trace gases slows over time, model results
indicate total column ozone depletion will also occur. (Exhibit
ES-3 shows various model projections for "what-if" scenarios.)
8. In all scenarios examined, substantial changes are expected in the vertical
distr'.bution of ozone. Ozone decreases are generally expected at higher
altitudes in all scenarios in which CFC concentrations increase. Ozone
increases are expected at lower altitudes in some scenarios examined due to
increases in methane concentrations. Such changes may have important
climatic effects.
9. Two-dimensional (2-D) models provide information on possible changes in
ozone by season and by latitude. Results from 2-D models suggest that
global average depletion could be higher than estimates from a
one-dimensional (1-D) model for the same scenario. Moreover, the 2-D model
results suggest that average annual ozone depletion above the global average
would occur at higher latitudes (above 40 degrees), while depletion over
tropics is predicted to be lower than the global average; and depletion
would be greater in the spring than the annual average. Uncertainties in
the representation of the transport of chemical species used in 2-D models
introduces uncertainty in the magnitude of the latitudinal gradient of ozone
depletion, but all 2-D models project a gradient.
Measurenents of Ozone
10. Measurements of ozone concentrations are another valuable tool for assessing
the risks of ozone modification. Based on analysis of data for over a
decade from a global network of ground-based monitoring stations, ozone
concentrations have decreased at mid-latitudes in the upper and lower
stratosphere and increased in the troposphere. According to studies using
ground-based instruments, there appears to have been no statistically
significant change in column ozone between 1970 and 1983. High altitude,
lower stratospheric, and total column trends are roughly consistent with
current two-dimensional model predictions.
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ES-8
EXHIBIT ES-3
Global Average Ozone Depletion: Emission Scenarios
10.0
-50.0
No Growth
Globally
No Growth
Globally --
Warming Llmltec
1985 2005 2025 2045 2065 2085
*This scenario assumes no growth in global production of ozone depleters, and
concentrations of other trace gases are prevented from rising to an amount
greater than that compatible with an increase in equilibrium global temperature
of 3.0°C ± 1.5°C by 2075.
Assumptions:
Current 1-D models accurately reflect global depletion; Antarctic ozone hole
has no impact on global ozone levels.
Greenhouse gases that counter depletion grow at historically-extrapolated
rates.
Growth rates for ozone depleters are for global emissions; it is assumed
that emissions do not increase after 2050.
Ozone depletion limited to 50 percent.
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ES-9
11. Recent evidence indicates that since the late 1970s substantial decreases in
ozone (up to 50 percent) have occurred over and near Antarctica during its
springtime. These losses have been verified by different measurement
techniques, and different theories have been suggested to explain the cause
of the seasonal loss in ozone. Insufficient data exist to state whether
chlorine and bromine are responsible for the observed depletion, or whether
some other factor is the cause (e.g., dynamics or changes in solar flux that
alters NOx). Furthermore, even if man-made chemicals are the cause of the
phenomenon, stratospheric conditions surrounding Antarctica are different
from the stratospheric conditions .for the rest of the world, so that it
cannot be assumed that similar depletion would occur elsewhere. Models did
not predict the Antarctic ozone depletion, however. Consequently, the
change in Antarctica suggests that ozone abundance is sensitive to yet
unknown natural or anthropogenic factors not yet incorporated in current
models.
12. Preliminary data from Nimbus-7 suggest a decrease in global ozone
concentrations (4-6 percent) may have occurred during the past several
years. These data have not yet been published and require additional review
and verification. If verified, further analysis would be required to
determine if chlorine is responsible for the reported decrease in ozone
levels, or whether the decrease is due to other factors or reflects
short-term natural variations.
Potential Health Effects from Ozone Depletion
13. Decreases in total column ozone would increase the penetration of
ultraviolet-B (UV-B) radiation (i.e., 290-320 nanometers) reaching the
earth's surface. (Exhibit ES-4 shows relative increases in UV-B at 295,
305, and 315 nanometers.)
14. Exposure to UV-B radiation has been implicated by laboratory and
epidemiologic studies as a cause of two common types of skin cancers
(squamous cell and basal cell). It is estimated that there are more than
400,000 new cases of these skin cancers each year. While uncertainty exists
concerning the appropriate action spectrum (i.e., the relative biological
effectiveness of different wavelengths of ultraviolet radiation), a range of
relationships was developed that allows increased incidence of these skins
cancers to be estimated for future ozone depletion (these cancers are also
referred to as nonmelanoma skin cancers).
15. Studies predict that for every 1 percent increase in UV-B radiation (which
corresponds to less than a 1 percent decrease in ozone because the amount of
increase in UV-B radiation, depending on the action spectrum, is greater
than rather than proportional to ozone depletion), nonmelanoma skin cancer
cases would increase by about 1 to 3 percent. The mortality for these forms
of cancer has been estimated at approximately 1 percent of total cases based
on limited available information.
16. Malignant melanoma is a less common form of skin cancer. There are
currently approximately 25,000 cases per year and 5,000 deaths. The
relationship between cutaneous malignant melanoma and UV-B radiation is a
complex one. Laboratory experiments have not succeeded in transforming
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ES-10
EXHIBIT ES-4
Increases in Ultraviolet Radiation
Due to a 1 percent Ozone Depletion
Talahaaa«e. Rorido
4 -
o
2
u
c
c
u
2 -
1 -
295
305
Wav«l«ngth (nm)
315
Ozone depletion would lead to increases in the amount of ultraviolet radiation,
particularly at the harmful lower wavelengths, that reaches the earth's surface,
Source: Estimates based on the ozone-UV model developed by Serafino and
Frederick (1986).
-------
ES-11
melanocytes with UV-B radiation. However, recent epidemiological studies,
including large case control studies, suggest that UV-B radiation plays an
important role in causing melanoma. Uncertainties in action spectrum, dose
measurement, and other factors necessitates the use of a range of
dose-response estimates. Taking .into account such uncertainties, recent .
studies predict that for each 1 percent change in UV-B intensity, the
incidence of melanoma could increase from 0.5 to 1 percent.
17. Studies have demonstrated that UV-B radiation can suppress the immune
response system in animals and possibly humans. While UV-B-induced immune
suppression has been linked to chronic reinfection with herpes simplex virus
and leishmaniasis in animals, its possible impact on other diseases and its
impact on humans has not been studied.
18. Increases in exposure to UV-B radiation are likely to increase the incidence
of cataracts and could adversely affect the retina.
Potential Effects on Plants and Aquatic Organisms
19. While studies generally show adverse impacts on plants from increased UV-B
exposure, difficulties in experimental design, the limited number of species
and cultivars tested, and the complex interactions between plants and their
environments prevent firm conclusions from being made for the purpose of
quantifying risks. Field studies on soybeans suggest that yield reductions
could occur in some cultivars of soybeans, while evidence fr^m laboratory
studies suggest that two out of three cultivars are sensitive to UV-B.
20. Laboratory studies with numerous other crop species also show many to be
adversely affected by UV-B. Increased UV-B has been shown to alter the
balance of competition between plants. While the magnitude of this change
cannot be presently estimated, the implications of UV-altered, competitive
balance for crops and weeds and for nonagricultural areas such as forests,
grasslands, and desert may be far reaching.
21. Aquatic organisms, particularly phytoplankton, zooplankton, and the larvae
of many fishes, appear to be susceptible to harm from increased exposure to
UV-B radiation because they spend at least part of their time at or near
surface waters. However, additional research is needed to better understand
the ability of these organisms to mitigate adverse effects and any possible
implications of changes in community composition as more susceptible
organisms decrease in numbers. The implications of possible effects on the
aquatic food chain requires additional study.
Effects of Depletion on Tropospheric Ozone and Polymers
22. Research has only recently been initiated into the effects of UV-B on the
formation of tropospheric ozone (an air pollutant with negative health and
plant effects). An initial chamber and model study shows that tropospheric
ozone levels could increase, resulting in additional urban areas being in
non-compliance with National Ambient Air Quality Standards. The increase in
UV-B would also produce ozone peaks closer to urban centers, exposing larger
populations to unhealthy concentrations of tropospheric ozone. The same
study also predicts substantial increase in hydrogen peroxide, an acid rain
precursor. However, because only one study has been done, the results must
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ES-12
be treated with caution. Additional theoretical and empirical work will be
needed to verify these projections.
23. Research indicates that increased .exposure to UV-B would likely cause
accelerated weathering of polymers, necessitating polymer reformulation or
the use of stabilizers in some products, and possibly curtailing use of
certain polymers in some areas.
Clinate Impacts front Trace Gas Growth
24. The National Academy of Sciences (NAS) has recommended that 1.5°C to 4.5°C
represents a reasonable range of uncertainty about the temperature
sensitivity of the Earth to a doubling of C02 or an increase in other trace
gases of the equivalent radiative forcing. While some of the trace gases
discussed above deplete ozone and others result in higher ozone levels, all,
on net, would increase the radiative forcing of the Earth and would
contribute to global warming.
25. Using the middle of the NAS range for the Earth's temperature sensitivity
and a wide range of future trace gas growth (e.g., from a phase-down of CFCs
by 80 percent from current levels by 2010 to a 5 percent annual increase
through 2050; C02 doubling by 2060; N20 increasing at 0.2 percent; CH4
increasing by 0.017 ppm/year through 2100), equilibrium temperatures can be
expected to rise from 4°C to 11.6°C by 2075. Of this amount, depending on
the scenario, uFCs and changes in ozone would be responsible for
approximately 15-25% of the projected climate change. (See Exhibit ES-5)
26. In most situations, inadequate information exists to quantify the risks
related to climate change. Studies predict that sea level could rise by
10-20 centimeters by 2025, and by 55-190 centimeters by 2075. Such
increases could damage wetlands, erode coastlines, and increase damage from
storms. Changes in hydrology, along with warmer temperatures, could affect
forests and agriculture. However, lack of information about the regional
nature of climatic change makes quantification of risks difficult. A study
suggests that rising temperatures could adversely affect human health if
acclimatization lags.
Summary of Potential Risk
27. To perform the computations necessary to evaluate the risks associated with
stratospheric modification, an integrating model was developed to evaluate
the joint implications of scenarios or estimates for: (1) potential future
use of CFCs and change in other trace gases; (2) ozone change as a
consequence of trace gas emissions; (3) changes in UV-B radiation associated
with ozone change; and (4) changes in skin cancer cases and cataracts
associated with changes in UV-B radiation. Potential impacts of
stratospheric modification that could not be quantified were not addressed
by the integrating model. On a global basis, the risks of ozone depletion
may be greatest for plants, aquatic systems and the immune system, even
though knowledge to assess these efforts is much less certain than for skin
cancers.
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ES-13
EXHIBIT ES-5
Equilibrium Temperature Change for the Six Emission Scenarios
Assuming 3.0'C Warning for Doubled C02*
12.0
9
3
4)
O>
C
0
s.
«
w
3
o
I.
a
E
5.0% Growth
i 3.8% Growth
2.5% Growth
1.2% Growth
No Growth
80% Redactio
1985
1995
2005
2015
2025
2035
2045
2055
2065
2075
* Computed assuming that the climate sensitivity to a doubling of carbon
dioxide is 3°C. This assumption is in the middle of the NAS range of 1.5°C to
4.5"C (see Chapter 6). Note that the actual warming that may be realized will
lag by several decades or more. To compute the equilibrium warming associated
with high or low NAS estimates multiply the y axis 'temperature change' by 1.5
or 0.5.
Growth levels refer to global estimates of production of all ozone
depleters.
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ES-14
28. Uncertainty about future risks is partly driven by the rate at which CFC and
Halon use and other trace gases grow or decline. For this reason, a wide
range of "what-if scenarios of potential CFC and Halon use and growth in
trace gas concentration was evaluated. To reflect the large uncertainties,
the scenarios range from an 80 percent global phase-down in the use of CFCs
by 2010 to an average annual growth in use of 5 percent per year from 1985
to 2050. For ozone-modifying gases other than CFCs, scenarios were based on
recently measured trends, with uncertainties being evaluated by considering
a range of future emissions and concentrations.
29. Across the wide range of "what-if scenarios considered, ozone change by
2075 could vary from as high as over 50 percent ozone depletion to increased
abundance of ozone of approximately 3 percent. This range of ozone change
implies a change in the number of skin cancer cases among people -alive today
and born through 2075 ranging from an increase of over 200 million to a
decrease on the order of 6.5 million. The overwhelming majority (over 95
percent) of the increases and decreases in skin cancer cases estimated for
this wide range of scenarios is associated with basal and squamous cell
cancers (i.e., nonmelanoma skin cancer). Mortality impacts are estimated co
be on the order of 1.5 to 2.0 percent of the changes in total cases, and a
large percentage of the estimated impacts are associated with people born in
the future. The statistical uncertainty of these estimates is on the order
of plus and minus 50 percent. Additional uncertainties exist, some of which
cannot be quantified. The greatest single uncertainty about future risks is
driven by the rate at which CFC and Halon use grows or declines. This
uncertainty is reflected in the assessment by examining a wide range of
"what if" scenarios of future use.
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ES-15
CHANGES IN ATMOSPHERIC COMPOSITION
The abundance of stratospheric- ozone depends upon chemical and physical
processes that create and destroy ozone. For over a decade scientists have
hypothesized that changes in the concentrations of trace gases in the atmosphere
could possibly perturb the processes that control ozone abundance and its
distribution at different altitudes. The findings of this section summarize the
currently available evidence on how emissions and concentrations of various
gases may change over time. The findings in this section can be found its
chapters 2 through 4 of the body of the risk assessment.
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ES-16
FINDINGS
1. HUMAN ACTIVITIES ARE THE ONLY SOURCE OF EMISSIONS FOR THREE CLASSES OF
POTENTIAL OZONE-DEPLETING CHEMICALS: CHLOROFLUOROCARBONS (CFCs):
CHLOROCARBONS (CARBON TETRACHLORIDE AND METHYL CHLOROFORM): AND HALONS
(chapter 3)z.
la. Since their development in the 1930s, CFCs have become useful
chemicals in a wide range of consumer and industrial goods, including:
aerosol spray cans; air conditioning; refrigeration; foam products
(e.g., in cushions and insulating foams); solvents (e.g.,
electronics); and a variety of miscellaneous uses.
Ib. CFC-11 (CC13F) and CFC-12 (CC12F2) have dominated the use and
emissions of CFCs, accounting for over 80 percent of current CFC
production worldwide. Because of increased demand for its use as a
solvent, CFC-113 (CC12FCC1F2) has become increasingly important as a
potential ozone-depleting chemical.
2. MEASUREMENTS OF TROPOSPHERIC CONCENTRATIONS OF INDUSTRIALLY PRODUCED
POTENTIAL OZONE-DEPLETING GASE-S SHOW SUBSTANTIAL INCREASES (chapter 2) .
2a. Measurements of current global average concentrations of CFC-11 are
200 parts per trillion volume (ppcv), CFC-12 are 320 pptv, CFC-113 are
32 pptv, carbon tetrachloride (CC14) are 140 pptv, and methyl
chloroform (CH3CCL3) are 120 pptv.
2b. Based on measurements from a global monitoring network, worldwide
concentrations of chlorine-bearing perturbants (i.e., potential ozone
depleters) have been growing annually in recent years at the following
rates: CFC-11 and CFC-12 at 5 percent; CFC-22 (CHC1F2) at 11 percent;
CFC-113 at 10 percent; carbon tetrachloride (CC14) at 1- percent; and
methyl chloroform at 7 percent.
2c. Limited measurements show that global tropospheric concentrations of
Halon 1211, a bromochlorofluorocarbon containing both chlorine and
bromine (which is potentially more effective at depleting ozone), have
been growing recently at 23 percent: annually. Concentrations have
been measured as one pptv.
2d. Measurements of tropospheric concentrations of Halon 1301, another
brominated compound that is a potential ozone depleter, estimate that
concentrations are approximately one pptv. No trend estimates have
been published.
The chapter references refer to the main body of the risk assessment.
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ES-17
3. ALMOST ALL EMISSIONS OF CFG-11. -12. -113. HALON 1211. AND HALON 1301
PERSIST IN THE TROPOSPHERE WITHOUT CHEMICAL TRANSFORMATION OR PHYSICAL
DEPOSITION. AS A RESULT. MOST OF THESE EMISSIONS WILL EVENTUALLY BE
TRANSPORTED TO THE STRATOSPHERE (chapter 2).
3a. Gases which are photochemically inert accumulate in the lower
atmosphere. Their emissions migrate to the stratosphere slowly.
Estimates of their atmospheric lifetimes (generally calculated based
on the time when 37 percent of the compound still remains in the
atmosphere) are the following: CFC-11 is 75 years (107/58 years);
CFC-12 is 111 years (400/55 years); CFC-113 is 90 years; CC14 is 50
years; Halon 1211 is 25 years; N20 is 150 years; and Halon 1301 is
110 years. (Where provided, the range in parentheses shows one
standard deviation).
3b. Because of their long atmospheric lifetimes, the concentrations of
these gases are currently far from steady state and will increase
over time unless there is a large reduction in future.emissions.
3c. Because of their long atmospheric lifetimes, these gases would
continue to contribute to possible future ozone depletion and climate
change (CFCs and other gases affecting ozone are also greenhouse
gases) long after they are emitted. Full recovery from any depletion
or climate change would take decades to centuries;
4. WHILE CFCs USED IN AEROSOLS DECLINED FROM 1974 UNTIL 1984. NONAEROSOL USES
OF CFCs HAVE GROWN CONTINUOUSLY AND APPEAR CLOSELY COUPLED TO ECONOMIC
GROWTH (chapter 3).
4a. From 1960 to 1974, the combined production of CFC-11 and CFC-12 from
both aerosol and nonaerosol applications grew at an average annual
rate of approximately 8.7 percent. Total global CFC-11 and -12
production peaked in 1974 at over 700 million kilograms.
4b. From 1976 to 1984, sales of CFC-11 and CFC-12 for aerosol
applications declined from 432 million kilograms to 219 million
kilograms, an average annual rate of decline of over 8 percent.
During the same period, sales for nonaerosol applications grew from
318 million kilograms" to 476 million kilograms, an average annual
compounded growth rate of 5 percent. By 1986, total CFC-11 and -12
global production was nearly that in 1974.
5. STUDIES OF FUTURE PRODUCTION OF CFCs-11 AND -12 PROJECT AN AVERAGE ANNUAL
GROWTH RATE OF APPROXIMATELY 1.0 TO 4.0 PERCENT OVER THE NEXT 15 TO 65
YEARS (chapter 3).
5a. A large number of studies of future global demand for CFCs were
conducted by experts from six countries under the auspices of the
United Nations Environment Programme. These studies used a variety
of methods for estimating both near- and long-term periods. In
general, these studies assumed that: (1) demand for CFCs was driven
by economic factors; (2) no additional regulations on CFC use were
imposed; and (3) consumers or producers do not voluntarily shift away
from CFCs because of concern about ozone depletion. These studies
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ES-18
provide a range of growth races for developing alternative baseline
scenarios of future CFC use and emissions.
5b. In general, these studies projected that CFC aerosol propellant
applications would remain constant or decrease further in many
regions of the world.
5c. In the U.S. over the past four decades new uses of CFCs have
developed first in refrigeration, then in aerosols, then in foam
blowing, and then in solvents.
5d. Studies have projected that growth in developed countries for
nonaerosol applications is expected to be driven by increased use in
foam blowing (primarily for insulation) and as solvents, and by the
continued introduction of new uses. The wide range of estimates of
future growth reflects the large uncertainties related to population
and economic growth, and technological change.
5e. Studies suggest that future CFC use. in developing countries will grow
faster (i.e., at a higher rate) than future CFC use in the developed
world. Nevertheless, the projected rates for the developing
countries are lower than the historical rates that have been
experienced in wealthier countries. While these studies were done
using aggregate relationships of GNP and CFC use, they made different
assumptions about how closely the pattern of CFC vise in developing
nations would replicate the pattern in developed nations, generally
assuming lower use rates. However, evidence from one recently
completed study (not completed at the time of the UNEP workshop)
indicates that in developing countries the penetration of CFC--using
goods may be occurring faster than expected on the basis of the
historical relationship in developed nations. If that study is
correct, growth in developing nations would be larger than projected
in the above-mentioned studies, which generally assumed less
penetration in developing nations than had occurred in developed
nations.
5f. Three long-term studies of CFC demand report annual average rates of
growth for CFC-11 and CFC-12 over the next 65 years ranging from 0.2
percent to 4.7 percent, with a median estimate of about 2.5 percent.
The "what-if" scenarios used for quantitative risk assessment in
Chapter 18 span a wider range of growth, including one scenario with
substantial decline.
5g. Limited studies on CFC-113 and CF.C-22 project that in the absence of
regulation or-voluntary shifts away from these chemicals, their
growth will increase at a faster rate than CFC-11 and -12 as new
markets develop and existing ones expand (e.g., use of CFC-113 as a
solvent in metal cleaning).
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ES-19
6. THE CHLOROCARBONS (METHYL CHLOROFORM AND CARBON TETRACHLORIDE) ARE USED
PRIMARILY AS SOLVENTS AND CHEMICAL INTERMEDIATES. ANALYSIS SUGGESTS
LIMITED FUTURE GROWTH FOR THESE CHEMICALS (chapter 3).
6a. Methyl chloroform is primarily used as a general purpose solvent.
Global use in 1980 was estimated at nearly 460 million kilograms.
Limited analysis of future demand indicates that it is expected to
grow at the rate of growth of economic activity (as measured by GNP).
Factors affecting future demand include possible control on it or
other solvents due to their health effects. Thus, use of methyl
chloroform could increase if other solvents are found more dangerous.
Similarly, its use could be increased if CFC-113 use is restricted.
Because methyl chloroform has a substantially shorter atmospheric
lifetime than CFC-113, it has relatively less potential for depleting
ozone.
6b. Carbon tetrachloride is primarily used to make CFCs in the U.S. In
developing countries it is also sometimes used as a general purpose
solvent. In general, future production and emission of carbon
tetrachloride is expected to follow the pattern of production of
CFCs.
7. HALONS. ON A PER POUND BASIS. POSE A GREATER THREAT (2-1/2 TO 12-1/2 TIMES')
TO OZONE DEPLETION THAN DO CFCs (chapter 3).
7a. Halons have been used in hand-held and total-flooding fire
extinguishers since the 1970s. Annual production has been limited
(approximately 20,000 kilograms) and emissions have been assumed to
be only a small fraction of production based on the assumption that
the halons remain inside the fire extinguishers. Recent research
suggests the' proportion of Halons released may be substantially
higher. In the U.S., industrial response to concern about depletion
from halons is likely to lead to some voluntary steps to curtail
emissions.
7b. A single study has projected future demand for Halons. It indicates
that near-term demand is growing rapidly and that production may
double by the year 2000. In that study, longer-term demand is judged
uncertain and may range from an average annual decline of 1 percent
from 2000 to 2050 to an annual increase exceeding 5 percent.
7c. The expected rate of Halon emissions is very uncertain. The one
study assumed most production would remain within fire extinguisher
systems as part of a growing Halon "bank." That study has been the
basis for scenarios used in this analysis.
7d. The historic growth in Halon 1211 concentrations (recently measured
at over 20% per year) is significantly higher than the rate assumed
for future years in the one existing study. .
•^ Since the Risk Assessment was drafted, another study has been developed;
see Chapter 3 Appendix. That study was not included in this Risk Assessment.
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ES-20
7e. Discussions with Halon users indicate that Halon 1301 emissions may
be underestimated in the study used for this risk assessment. A
recent survey showed that existing systems are undergoing widespread
testing and accidental discharge occurs more frequently than assumed
in prior studies.
7f. Additional analysis of Halon emission estimates are necessary to
assess more adequately the risks associated with this trace gas.
8. FUTURE CONCENTRATIONS OF STRATOSPHERIC PERTURBANTS THAT HAVE AT LEAST SOME
BIOGENIC SOURCES. CARBON DIOXIDE. METHANE. AND NITROUS OXIDE. ARE DIFFICULT
TO PROJECT (chapter 4).
8a. The size of existing source terms (wetland areas, for example) is not
known with certainty today for all these trace species. Greatest
uncertainty exists for methane, least for C02. To estimate future
emissions reliably requires estimating the growth of source terms
(e.g., acreage of rice paddies, wetlands area), which will be
determined by many technical, political, environmental, and social
factors.
8b. Current emission factors for each source term must be estimated; some
are not known today or have not been reliably estimated (emissions
from soils, for example).
8c. Possible changes in emission factors due to changes in the
environment must be projected. Projection of changes is difficult
because the underlying physical or biological processes that
determine emissions are not well understood and because changes in
the environment that could alter emissions are not easy to project.
8d. Biogeochemical cycles that control the fate of emissions once
released into the atmosphere must be understood to determine future
concentrations of these trace species; severe limitations to our
current understanding of these cycles limits our capacity to
determine the consequences of changing emissions in the future.
8e. Possible changes in these biogeochemical cycles due to changes in the
environment must be projected; again deficiencies in existing
knowledge makes this task difficult.
9. DESPITE THE UNCERTAINTIES ASSOCIATED WITH EACH OF THESE FACTORS.
RESEARCHERS HAVE DEVELOPED SCENARIOS FOR THREE GASES WHICH ARE COMMONLY
USED. IN THIS RISK ASSESSMENT A SCENARIO CONSISTENT WITH ONES USED IN THE
ATMOSPHERIC COMMUNITY'S WILL BE ADOPTED. AS WELL AS SEVERAL SENSITIVITY
SCENARIOS TO EXAMINE THE SENSITIVITY OF ATMOSPHERIC EVOLUTION TO THE
SCENARIOS (chapter 4).
Since this risk assessment was originally completed, Halon users in the
U.S. have taken a variety of steps to reduce emissions. This step is not
considered in this Risk Assessment.
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9a. The scenarios used in this risk assessment are consistent with that
commonly used by the atmospheric community and assume the following
changes in trace gas concentrations:
o for C02, a scenario developed by the National Academy of
Sciences (its 50th percentile, i.e., pre-industrial C02
concentrations doubling by about 2065);
o for CH4, -a linear increase in concentrations of 0.017 ppm
per year;
o for N20, concentration increases of.0.2 percent per year.
9b. Additional scenarios used to analyze risks will include:
- for C02
o NAS 25th percentile (pre-industrial concentrations
doubling by 2100)
o NAS 75th percentile. (pre-industrial concentrations
doubling by 2050)
- for CH4
o 0.01275 ppm per year growth in concentrations (75
percent of the historically observed 0.017 ppm per
year increase)
o 0.02125 ppm per year growth in concentrations (125
percent of the historically observed 0.017 ppm per
year increase)
o 1 percent compound growth per year in concentrations
o 1 percent compound growth per year in concentrations
from 1985 to 2010, followed by constant concentrations
at 2.23 ppm
o 1 percent compound growth per year in concentrations
from 1985 to 2020, growing to 1.5 percent compound
annual growth by 2050 and thereafter
- for N20
o 0.15 percent per year compound growth in
concentrations
o 0.25 percent per year compound growth in
concentrations
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10. DECISION MAKERS SHOULD BE MADE AWARE THAT THE MOST COMMONLY USED SCENARIOS
IN STRATOSPHERIC MODELING IMPLICITLY ASSUME THAT FUTURE DECISION MAKERS
NEVER TAKE ACTION TO LIMIT THE RISE IN CONCENTRATIONS OF CARBON DIOXIDE.
METHANE. AND NITROUS OXIDE. THREE GASES CONTRIBUTING TO THE GREENHOUSE
WARMING (chapter 4).
lOa. The standard assumption in most atmospheric modeling has been, by
default, that greenhouse gases will be allowed to increase without
limit regardless of the level of global warming that occurs or is
projected.
lOb. In order to provide decision makers with adequate information to
assess the risks of ozone modification due to rising CFCs and Halons,
alternative assumptions about the future of greenhouse gases need to
be examined. Two scenarios are examined:
limiting global warming to 2°C.
limiting global warming to 3°C.
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POTENTIAL CHANGES IN OZONE AND CLIMATE
MODELS OF THE ATMOSPHERE THAT INCORPORATE CURRENT SCIENTIFIC UNDERSTANDING
OF CHEMISTRY AND PHYSICS PROJECT CHANGES IN GLOBAL OZONE (TOTAL COLUMN AND/OR
VERTICAL DISTRIBUTIONS'AND INCREASES IN GLOBAL SURFACE TEMPERATURE IF TRACE GAS
CONCENTRATIONS GROW SIGNIFICANTLY. UNCERTAINTIES ABOUT MAGNITUDES REMAIN LARGE.
Models that incorporate current scientific understanding are used as the
primary tool to project the potential consequences of future changes in
abundances of trace gases. These models can be partly tested by comparing their
results with measurements of the atmospheric, historically observed changes in
ozone, and in the case of climate, with paleoclimatic and extraterrestrial
environments. While current models accurately represent some aspects of the
atmosphere, they fail to.replicate other characteristics. This section
summarizes the currently available evidence on how changing atmospheric
abundance could modify total column ozone, alter column distribution, and change
global climate.
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FINDINGS
11. STRATOSPHERIC MODELING PROJECTS THAT THE COMBINED EFFECTS OF A VARIETY OF
TRACE GASES (CHLOROFLUOROCARBONS. NITROUS OXIDE. CARBON DIOXIDE. HALONS.
AND METHANE) ARE LIKELY TO REDUCE THE COLUMN DENSITY OF OZONE UNLESS
EMISSIONS OF OZONE DEPLETERS ARE PREVENTED FROM GROWING (chapter 5).
lla. Photochemical theory continues to support the conclusion that
chlorine, nitrogen, and hydrogen can catalytically destroy ozone in
the stratosphere, thus depleting column levels.
lib. One-dimensional (1-D) models currently predict a 5-9 percent
depletion for the equilibrium concentrations of chlorine that would
result from constant emission of CFCs at 1977 levels. While useful
for intercomparing models, these values cannot be used to assess the
risks of depletion in an atmosphere in which other gases are also
changing.
lie. One-dimensional (1-D) models predict average column ozone will
decrease if global emissions of CFCs and other ozone depleters
continue to rise from current levels, even if concentrations of
methane, carbon dioxide, and nitrous oxide continue to grow at past
rates. For a 3 percent growth of CFCs, models predict over a 25
percent depletion by 2075 if the other gases continue to grow.
lid. Two-dimensional models (2-D) used in steady state multi-perturbant
studies that include chlorine, methane, and nitrous oxide project
depletion higher than global averages at latitudes greater than 40°N,
especially in the spring.
lie. Time-dependent simulations of stratospheric change in which 2-D
models are used predict that depletion over 4 percent will occur at
some latitudes for all cases of positive growth in CFC emissions.
Such models even predict ozone depletion of up to 3 percent at
inhabited latitudes for a scenario in which emissions of chlorine-
bearing substances are reduced from current to 1980 levels and in
which halon emissions are eliminated, but in which the greenhouse
gases that counter depletion are allowed to grow at historical rates.
llf. Time-dependent simulation with one 2-D model, with CFCs growing at 3
percent, methane rising at 1 percent, nitrous oxide at 0.25 percent
and carbon dioxide growing at 0.6 percent, projects annual average
depletion at 40°N of approximately 1.1 percent by 2000 and 5.2
percent by 2030. At 50°N, depletion is projected to be 1.5 percent
by 2000 and 6.5 percent by 2030. At 60°N, depletion is projected to
be 2.1 percent by 2000 and 8.1 percent by 2030. Springtime depletion
would be higher.
llg. Time-dependent simulation with one 2-D model, with CFC-11 and -12
emissions rolled back to 1980 levels, CFC-113 capped, other
chlorinated emissions and bromine emissions eliminated, methane.
rising at 1 percent, nitrous oxide at 0.25 percent, and carbon
dioxide at 0.6 percent, projects depletion by 2030 of about 0.5
percent at 40°N, 0.7 percent at 50°N, and 1.1 percent at 60°N (these
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ES-25
depletion values are from 1985 levels). If carbon dioxide
concentrations are prevented from growing from current levels,
depletion would be anticipated to be higher.
llh. Time-dependent simulations with two other two-dimensional models show
roughly comparable results to those reported here, with a slightly
less latitudinal gradient. However, these models also project
latitudinal gradients from equatorial to polar and regions.
Hi. Because of possible increases in the emissions of bromine molecules
(see Chapter 4), Halons present a more important risk for
stratospheric depletion than has generally been appreciated.
12. CURRENT THEORY AND MODELS FAIL TO REPRESENT ALL OBSERVATIONAL MEASUREMENTS
OF THE ATMOSPHERE AND PROCESSES THAT WILL INFLUENCE STRATOSPHERIC CHANGE IN
A COMPLETE AND ACCURATE MANNER (chapter 5).
12a. While accurately reproducing many measurements in the- current
atmosphere, current models fail to reproduce some measurements; the
amount of ozone at 40 kilometers is underestimated, for example.
12b. While including representations of most atmospheric processes,
current models fail to include all the processes that influence
stratospheric composition and structure in a realistic manner.
Transport processes, for example, are represented in a simplified
manner that does not encompass all the complications of movement in
the real atmosphere.
12c. The inability of models to wholly reproduce measurements of the
current atmosphere lowers our confidence in them to predict the
future; it is possible that models are over- or under-predicting
future depletion.
13. UNCERTAINTY ANALYSES THAT CONSIDER A RANGE OF POSSIBLE VALUES FOR CHEMICAL
AND PHYSICAL INPUTS CRITICAL FOR MODEL ESTIMATION OF DEPLETION INDICATE
THAT DEPLETION IS LIKELY IF CFCS CONTINUE TO GROW (chapter 5).
13a. Uncertainty analyses conducted with one-dimensional models predict
depletion for a variety of CFG levels.
13b. Uncertainty analyses using different sets of kinetics and cross
sections have not been tested in two-dimensional models. However,
different 2-D models have used different approaches for transporting
species. This provides a useful test of the sensitivity of model
predictions to the uncertainty of how transport actually works.
While differing somewhat in the latitudinal gradients of depletion,
the models with different transport both predict depletion that
increases with distance from the equator.
13c. Not all uncertainties can be tested in the modeling process. The
possibility that missing factors may lead to a greater or lesser
depletion than indicated in formal uncertainty analyses cannot be
excluded.
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14. OZONE MONITORING SHOWS CHANGES IN OZONE ROUGHLY CONSISTENT WITH MODEL
PREDICTIONS. WITH TWO EXCEPTIONS (chapter 5).
14a. Measurements by balloons and Umkehr show 3 percent depletion at
mid-latitudes in the upper atmosphere, 1.3 percent depletion in the
lower stratosphere, and 12 percent increases in the lower
troposphere. Uncertainty exists about the accuracy of all these
observations. These results, however, are roughly consistent with
the expectations generated by one-dimensional and two-dimensional
models. The ground based measurement system covers only a small part
of the Earth and is limited at high latitudes.
14b. Nimbus 7 measurements appear to show a decrease in global ozone,
especially at both poles. However, the decrease in Arctic ozone from
1978 to 1984 may have occurred only in the last several years.
Concern exists about calibration problems, which make an exact
determination of the absolute magnitude of depletion difficult.
However, the latitudinal variations in depletion seem .to indicate
that a real phenomenon is being observed, not just instrumental
drift.
14c. The cause of these apparent ozone decreases measured by Nimbus 7 has
not been sufficiently analyzed to determine whether the changes (if
they are real) can be attributed to manmade chemicals. Other
possible explanations include natural variations caused by solar
cycles or other processes. The latitudinal gradients of the changes,
are, however, roughly consistent with those projected by 2-D model
results, although the magnitude is substantially larger than models
predict. Until further analysis is performed to determine whether
depletion is actually occurring and whether it can be attributed to
man-made chemicals, models to assess risks to the stratosphere should
not be revised.
14d. Measurements in the Antarctic spring show that the gradual depletion
that occurred in the mid-1970s over and near Antarctica has given way
to a steep non-linear depletion from 1979 to 1985. The ozone maximum
outside Antarctica (between 50°S and 70°S) appears to be showing a
decline. The depletion of all areas south of 80°S appears to be 16
percent.
14e. Models with conventional chemistry do not predict "the Antarctic
ozone hole." Care should be exercised in interpreting the meaning of
the phenomenon. Several hypotheses have been put forward, including
a chemical explanation that attributes the loss of ozone to manmade
sources (bromine and chlorine), a chemical explanation that
attributes the loss to natural sources (NOx, solar cycle), or an
explanation that claims the phenomenon is entirely due to the change
in climate dynamics. Until more is understood about the true causes
of the hole, it is impossible to determine whether the hole is a
precursor of atmospheric behavior that will occur in other regions of
the world. Until a better understanding of the mechanisms creating
the depletion is obtained, the existence of the Antarctic ozone hole
should not be used as a basis for making regulatory decisions.
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14f. This risk assessment will assume that Antarctic ozone and global
trends have no implications for global projections. Future reviews
should update this conclusion as necessary.
15. INCREASES IN THE ABUNDANCE OF CFCs AND OTHER TRACE GASES CAN INCREASE
GLOBAL TROPOSPHERIC SURFACE TEMPERATURES. THESE GASES CAN ALTER THE
VERTICAL DISTRIBUTION OF OZONE AND INCREASE STRATOSPHERIC WATER VAPOR.
THEREBY INFLUENCING GLOBAL WARMING (chapter 6).
15a. Trace gases that act as stratospheric perturbants also are greenhouse
gases--as their concentrations increase in the troposphere they will
retard the escape of infrared radiation from earth, causing global
warming.
15b. Increases in methane (CH4) will also add water vapor to the
stratosphere, thereby enhancing global wanning. Methane increases
will also add ozone to the troposphere, where it acts as a strong
greenhouse gas that will further increase global warming.
15c. In all model-generated scenarios of ozone depletion, ozone decreases
in the stratosphere above 28 km. This allows more ultraviolet
radiation to penetrate to lower altitudes where the "self-healing
effect" increases ozone to partially compensate for the ozone loss
above. In some scenarios sufficient depletion occv-s so that ozone
eventually decreases at all altitudes.
15d. Decreases in ozone at approximately 28 km or above will have a
warming effect on the Earth. There is a small net gain in energy
because the increase in ultraviolet radiation (UV-B) allowed to reach
the earth's surface more than compensates for the infrared radiation
that is allowed to escape due to depletion of ozone above that
altitude.
15e. Below approximately 28 km, increases in ozone are more effective as
absorbers of infrared radiation. Consequently, increases in ozone
below 28 km also will produce a net warming. In this case, the
additional UV blocked by more ozone is less than the additional
infrared that is blocked from escaping the earth. Conversely, a
decrease in ozone below 28 km will tend to cool the Earth's surface.
15f. The direct effect of column depletion of ozone on global temperatures
will depend on the magnitude of the depletion. Until the depletion
is of sufficient magnitude that it occurs at the lower part of the
column, ozone depletion will be a net contributor to global warming.
If the stratosphere continues to deplete so that ozone is depleted
below 28 km, this depletion will cause a cooling. One-dimensional
models differ from two-dimensional models in the vertical
distribution of ozone change, with depletion occurring at all
altitudes in the higher latitudes in two-dimensional models, rather
than just at high altitudes. Thus, according to 2-D models, the
changes in radiative balance will be latitude dependent. At the
current time, no studies have been undertaken to determine the net
radiative forcing of changes projected by 2-D models.
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15g. Radiative forcing may vary strongly with changes in ozone at
different altitudes and latitudes. Consequently, until comparisons
are made between the models in terms of their global impact,
estimates of the effects of changes in the vertical column of ozone
on global warming made with 1-D models must be viewed cautiously, in
addition, changed vertical distribution of ozone could influence
stratospheric dynamics.
16. INCREASES IN TRACE GAS CONCENTRATIONS ASSOCIATED WITH STRATOSPHERIC
MODIFICATION ARE LIKELY TO WARM THE EARTH SIGNIFICANTLY (chapter 6).
16a. Two National Academy of Sciences panels have concluded that the
equilibrium warming for doubling atmospheric concentrations of C02,
or for an equivalent increase in the radiative forcing of other trace
gases, will most likely be between 1.5° and 4.5°C.
16b. The magnitude of warming that would be directly associated with
radiative forcing from increases in trace gases without feedback
enhancement would increase temperature by approximately 1.2°C for a
doubling of C02, and approximately an additional 0.45°C for a
simultaneous doubling of N20 and CH4. Direct radiative forcing from
a uniform 1 ppb increase in both CFC-11 and CFC-12 would increase
temperature by about 0.15°C.
16c. The initial warming from direct radiative forcing would change some
of the geophysical factors that determine the earth's radiative
balance (i.e., feedbacks will occur) and these changes would amplify
the initial warming. Increased water vapor and altered albedo
effects (snow and ice melting, reducing the reflection of radiation
back to space) have been projected by several modeling groups to
increase the warming by as much as 2.5°C for doubled C02 or its
radiative equivalent. Large uncertainties exist about the
feedbacks between global warming and clouds, which could further
amplify, or possibly reduce, the magnitude of warming.
16d. The three major general circulation modeling groups in the U.S.
estimate an average global warming of around 4°C for doubled C02 or
its radiative equivalent. However, because of uncertainties in the
representation of the cloud contributions, greater or lesser
amplifications, including a negative feedback that would reduce the
wanning to 2°C or an even lower value, cannot be ruled out.
16e. Global average temperature has been estimated as having risen about
0.6°C over the last century. This increase is consistent with
general predictions of climate models. Attempts to use these data to
derive empirically the temperature sensitivity of the earth to a
greenhouse forcing are not likely to succeed. Uncertainty about the
past concentrations of trace gases in the atmosphere, other exogenous
factors that affect the climate (such as aerosols or solar input),
and oscillation and instabilities in the internal dynamics of the
climate system (such as ocean circulation), currently prevent the
derivation of the earth's temperature sensitivity from examination of
the historic rise of temperature. This limitation is likely to
remain for more than another decade.
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16f. The global wanning associated with increases in ozone-modifying gases
varies with scenarios of future growth in these gases. If the use of
CFCs grows at 2.5 percent per year through 2050, C02 concentrations
grow at the 50th percentile rate defined by the NAS (approximately
0.6 percent per year from 1985 to 2050), N20 concentrations grow at
0.20 percent per year, and CH4 concentrations grow at 0.017 ppm per
year (approximately 1.0 percent of current concentrations), then
equilibrium temperatures would rise by about 5.6°C by 2075 (relative
to observed temperature in 1985),. based on a temperature sensitivity
of 3°C for doubled C02. Values would be about 50 percent higher for
a 4.5°C-based temperature sensitivity and about 50 percent lower for
1.5°C. If CFC use remains constant through 2050, the projected
warming would be about 4.3°C by 2075 (± 50%), and if use were phased
out by 2010, projected warming would be about 4.0°C (± 50%).
16g. Efforts to gather worldwide time series data for clouds have begun.
If adequate, these data may narrow estimates of the cloud
contribution to temperature sensitivity within the next decade.
However, because of the complexity of this issue, this effort may
fail to resolve the large uncertainties affecting this aspect of
climate.
17. THE.TIMING OF GLOBAL WARMING DEPENDS ON THE RATES AT WHICH GREENHOUSE GASES
INCREASE. THE RATES AT WHICH OTHER FORCINGS SUCH AS VOLCANOES AND SOLAR
' RADIATION CHANGE. *ND THE RATE AT WHICH OCEANS TAKE UP HEAT AND PARTIALLY
DELAY TEMPERATURE EFFECTS. A GLOBAL WARMING GREATER THAN VARIATIONS THAT
QCrURRED THIS PAST CENTURY IS EXPECTED IN THE NEXT TEN YEARS IF VOLCANIC
AND SOLAR FACTORS DO NOT SUBSTANTIALLY CHANGE (chapter 6).
17a. The delay in temperature rise introduced by absorption of heat by the
oceans can only be roughly estimated. The simple one.-dimensional
models of oceans that have been used for this purpose do not
realistically portray the mechanisms for heat transport into the
oceans. Instead, these models use eddy diffusion to treat heat in a
parameterized manner so that heat absorption is consistent with data
from the paths of transient tracers. These models indicate that the
earth will experience substantial delays (on the order of several
decades) in experiencing the full wanning from greenhouse gases.
17b. The earth's current average temperature is not in equilibrium with
the radiative forcing from current concentrations of greenhouse
gases. Consequently, global average temperature would increase in
the future even if concentrations of gases did not rise any further.
For example, if 2°C is the actual sensitivity of the earth's climate
system to a C02 doubling, simple models estimate the current
"unrealized warming" to be approximately 0.34°C; for a 4°C
temperature sensitivity, the current unrealized warming would be
approximately 1.0°C.
17c. Only one three-dimensional general circulation model has been used to
simulate changes in temperature as concentrations of greenhouse gases
increase over time. This simulation shows a faster wanning than
predicted by simpler one-dimensional models that use ocean box models
to simulate time-dependent warming.
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17d. Future uptake of heat by the oceans may change as global warming
alters ocean circulation, possibly altering the delaying effect of
the oceans as well as reducing their uptake of C02.
17e. Inadequate information exists to predict how volcanic or solar
forcings may change over time. Analyses done of transient warming
assume that past levels of volcanic aerosols will continue into the
future and that solar forcing changes will average out over
relatively short periods of time.
18. WITH A FEW GENERALIZED EXCEPTIONS. THE CLIMATIC CHANGE ASSOCIATED WITH
GLOBAL WARMING CANNOT BE RELIABLY PREDICTED ON A REGIONAL BASIS
(chapter 6).
18a. In general, as the earth warms, temperature, increases will be greater
with increasing distance from the equator.
18b. Global warming also can be expected to increase precipitation and
evaporation, intensifying the hydrological cycle. While models lack
sufficient reliability to make projections for any single region, all
perturbation studies with three-dimensional models (general
circulation models) show significant regional shifts in dryness and
wetness, which suggests that shifts in hydrologic conditions will
occur throughout the world.
18c. Current general circulation models represent oceanic, biospheric, and
cloud processes with insufficient realism to determine how extreme
weather events and climatic norms are likely to change on a regional
basis. For example, one analysis of general circulation model
outputs suggests that the frequency of extreme climatic conditions
will change in many regions of the world. Another model projects
increased summer drying in mid-latitudes for perturbation studies,
utilizing either of two different representations of clouds. Still
another analysis suggests changes in latitudinal gradients of sea
surface temperature will1play a critical role in determining regional
climatic effects.
19. LIMITING GLOBAL WARMING BY REDUCING EMISSIONS OF STRATOSPHERIC PERTURBANTS
THAT TEND TO INCREASE OZONE WOULD INCREASE THE STRATOSPHERE'S VULNERABILITY
TO OZONE DEPLETION. UNDER SCENARIOS IN WHICH CONTINUED BUFFERING OF OZONE
DEPLETION BY OTHER TRACE GASES IS ASSUMED. SUBSTANTIAL GLOBAL WARMING
RESULTS (chapter 6).
19a. Decreases in substance? with the potential to deplete stratospheric
ozone--that is, chlorofluorocarbons and nitrous oxides--would
decrease the rate and magnitude of global warming.
•
19b. Decreases in methane emissions, which have the potential to increase
stratospheric and tropospheric ozone and thereby buffer ozone
depletion, would decrease warming in three ways: by reducing direct
radiative effects from its presence in the troposphere; by lowering
water vapor in the stratosphere; and by reducing ozone build-up below
28 km.
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19c. Decreases in C02 emissions would decrease global wanning, but would
also have the effect of increasing the stratosphere's vulnerability
to ozone depletion.
19d. Decreases in carbon monoxide concentrations, which may occur as
energy production practices change, could result in decreases in
methane concentrations by increasing OH-radical abundance which, in
turn, would shorten the lifetime of methane and could shorten the
lifetime of methyl chloroform and CFC-22.
20. ADDITIONAL RESEARCH IS NEEDED ON CLIMATE TO REDUCE UNCERTAINTIES ABOUT
GLOBAL WARMING ASSOCIATED WITH TRACE GAS GROWTH (chapter 6).
20a. The key to improving the accuracy of estimates of global temperature
sensitivity is to acquire a better understanding of the effect of
clouds. This recommendation has been made by numerous groups over
the last decade; yet research devoted to this issue remains
relatively small.
20b. An increased understanding of ocean circulation is critical to
improving estimates of timing and regional projections.
20c. The effect of climate on biological systems and soils and their
impact on climate must be modeled if regional estimates of climate
change are to be developed.
20d. A better understanding of the radiative properties of CFC-113 and
other compounds is needed for estimating the effects of this compound
on climate.
20e. Experiments with three'dimensional models that have altered scenarios
of vertical ozone need to be undertaken to assess the possible
impacts on the magnitude of global warming and on general
circulation.
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.HUMAN HEALTH, WELFARE, AND ENVIRONMENTAL EFFECTS
CHANGES IN COLUMN OZONE ABUNDANCE AND DISTRIBUTION AND A RISE IN GLOBAL
TEMPERATURE WOULD BE EXPECTED TO HARM HUMAN HEALTH. WELFARE. AND THE
ENVIRONMENT. SOME RISKS CAN BE QUANTIFIED USING RANGES. OTHER RISKS
CANNOT BE QUANTIFIED OR DATA NECESSARY FOR QUANTIFICATION ARE AVAILABLE
ONLY FOR LIMITED CASE STUDIES.
Ozone shields Che earth from UV-B radiation. A decrease in total
column ozone will increase this radiation, especially at its most harmful
wavelengths. For the DNA action spectrum, a 1 percent depletion would
increase the weighted UV flux by about 2 percent. Changes in column ozone
and increases in global temperatures could alter many environmental
conditions. The findings of this section cover the effects of these
changes on human health, ecosystems, crops, materials, air pollution, sea
level and other areas that influence human welfare.
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FINDINGS
21. BASED ON SURVEYS (PARTICULARLY IN THE UNITED STATES AND IN AUSTRALIA).
PROLONGED SUN EXPOSURE IS CONSIDERED TO BE THE DOMINANT RISK FACTOR FOR
NONMELANOMA SKIN TUMORS (chapter 7).
21a. Nonmelanoma skin tumors tend to develop in sun-exposed sites (e.g.,
the head, face, and neck).
21b. Higher incidence rates occur among groups subject to greater exposure
to the sun's rays because of occupations that necessitate their
working outdoors.
21c. A latitudinal gradient exists for UV-B radiation, and higher
incidence rates of nonmelanoma skin tumors generally occur in
geographic areas of relatively high UV radiation exposure.
21d. Skin pigmentation provides a protective barrier that reduces the risk
of developing nonmelanoma skin tumors.
21e. The risk of nonmelanoma'skin tumors is highest among genetically
predisposed individuals (e.g., those with xeroderma pigmentosum).
21f. A predisposition to develop nonmelanoma skin tumors exists among
light-skinned individuals (skin phenotypes I and II) who are
susceptible to sunburn and who have red/blond hair, blue/green eyes,
and a Celtic heritage.
22. AVAILABLE EPIDEMIOLOGICAL EVIDENCE INDICATES THAT THE TWO MAJOR TYPES OF
NONMELANOMA SKIN TUMORS. SOUAMOUS CELL CARCINOMA (SCO AND BASAL CELL
CARCINOMA fBCC)..RESPOND DIFFERENTLY TO SOLAR EXPOSURE. IT HAS BEEN
SUGGESTED THAT CUMULATIVE UV RADIATION HAS A GREATER EFFECT ON THE
DEVELOPMENT OF SCC THAN ON BCC (chapter 7).
22a. The BCC/SCC incidence ratio decreases with decreasing latitude and
therefore, increasing UV levels.
22b. BCC is more likely to develop on normally unexposed sites (e.g., the
trunk) compared to SCC.
22c. SCC is more likely than BCC to develop on sites receiving the highest
cumulative UV radiation doses (e.g., the nose).
22d. For a given cumulative level of sunlight exposure, the risk of
developing SCC may be greater than the risk of developing BCC.
23. THE RESULTS FROM SEVERAL EXPERIMENTAL STUDIES SUGGEST THAT UV-B MAY BE THE
MOST IMPORTANT COMPONENT OF SOLAR RADIATION THAT CAUSES VARIATIONS IN THE
INCIDENCE OF NONMELANOMA SKIN TUMORS (chapter 7).
23a. UV radiation produces nonmelanoma skin tumors in animals. UV-B
wavelengths have been shown to be most effective in producing these
tumors.
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23b. UV-B has been shown to cause a variety of DNA lesions, to induce
neoplastic transformation in cells, and to be a mutagen in both
animal and bacterial cells.
24. SEVERAL RESEARCHERS HAVE INVESTIGATED THE CHANGES IN THE INCIDENCE OF
NONMELANOMA SKIN TUMORS THAT MAY RESULT FROM INCREASES IN EXPOSURE TO SOLAR
UV RADIATION. GIVEN UNCERTAINTIES. RANGES OF ESTIMATES OF INCREASED
INCIDENCE THAT COULD OCCUR WITH DEPLETION ARE ESTIMATED (chapter 7).
24a. The action spectra for initiation and promotion of basal cell and
squamous cell skin cancer have not been precisely determined.
Photocarcinogenic studies indicate that the erythema and DNA action
spectra span a range likely to encompass that of squamous cell and
basal cell skin cancer. The Robertson-Berger .(R-B) meter, while
providing useful data for describing ambient UV radiation, does not
relate as closely to those wavelengths thought to promote sunburn and
skin cancer.
24b. Several studies have provided estimates of a biological amplification
factor (BAF), which is defined as the percent change in tumor
incidence that results from a 1 percent change in UV-B radiation.
The results from six studies produced an overall BAF range that is
1.8-2.85 for all nonmelanoma skin tumors.
24c. BAF estimates are generally higher for males than for females and
generally increase with decreasing latitude. In addition, the BAF
estimates for SCC are higher than the BAF estimates for BCC. This
finding is consistent with observations that the BCC/SCC ratio
decreases with decreasing latitude and that BCC is more likely to
develop on unexposed sites.
24d. Optical amplification (the change in UV-B radiation related to ozone
depletion) increases the response of these cancers to ozone
depletion, because the relevant action spectra increase more than 1
percent for a 1 percent depletion. For example, a 1 percent
depletion has an optical amplification of over 2 for the DNA action
spectrum.
24e. Uncertainty exists in the actual doses of solar UV radiation received
by populations and in the statistical estimates of the dose-response
coefficients. Therefore, a range of estimates must be developed for
changes in incidence associated with changes in dose.
24f. Currently available nonmelanoma mortality data are of uncertain
accuracy because of the discrepancy of reporting between death
certificates and hospital diagnoses and the low proportion of deaths
reported on both hospital diagnoses and death certificates. Based* on
published studies, the rates of metastasis among SCCs and BCCs have
been estimated to be 2-20% and 0.0028-0.55%, respectively. The
overall case fatality rate for nonmelanoma skin tumors is
approximately 1-2% with three- fourths to four-fifths of the deaths
attributable to SCC.
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24g. Changes in behavior have tended to increase skin cancer incidence and
mortality. While some evidence exists that this is reaching a limit,
skin cancer rates, even in the absence of ozone depletion, would be
likely to rise. Future rates of skin cancer could be reduced if.
people changed their behavior. Care should be taken, however, in
interpreting such a change as a 'cost-free' response.
25. CUTANEOUS MALIGNANT MELANOMA (CMM) IS A SERIOUS LIFE-THREATENING DISEASE
THAT AFFECTS A LARGE NUMBER OF PEOPLE IN THE UNITED STATES. THERE ARE
SEVERAL HISTOLOGICAL FORMS OF MELANOMA THAT ARE LIKELY TO HAVE SOMEWHAT
DIFFERENT ETIOLOGIES AND RELATIONSHIPS TO SOLAR AND UV-B RADIATION (chapter
8).
25a. CMM incidence and mortality is increasing among fair-skinned
populations. These increases appear not to be merely the result of
improved diagnosis and reporting.
25b. In 1987, it is estimated that there will be an estimated 25,800 cases
of CMM and 5,800 fatalities related to melanoma in the United States.
In the absence of ozone depletion, the lifetime risk of CMM in the
United States is expected to be about 1 in 150.
26. LIMITATIONS IN THE DATABASE PREVENT ABSOLUTE CERTAINTY ABOUT THE
RELATIONSHIP OF SOLAR RADIATION. UV-B. AND CUTANEOUS MALIGNANT MELANOMA
(CMM) (chapter 8).
26a. There currently is no animal model in which exposure to UV-B
radiation experimentally induces melanomas.
26b. There is also no experimental in vitro model for malignant
transformation of melanocytes.
26c. No epidemiologic studies of CMM have been conducted in which
individual human UV-B exposures (and biologically effective doses of
solar radiation) have been adequately assessed.
27. EVALUATION OF THE EPIDEMIOLOGICAL AND EXPERIMENTAL DATABASES FOR MELANOMA
REQUIRES CLOSE ATTENTION TO THE RELATIONSHIP OF WAVELENGTH AND DOSE AND TO
THE VARIATIONS OF SOLAR RADIATION IN THE AMBIENT ENVIRONMENT (chapter 8).
27a. Ozone differentially removes wavelengths of UV-B between 295 and 320
nm; UV-A (320-400 nm) in wavelengths above 350 nm is not removed, nor
is visible light (400-900 nm). Ozone removes all UV-C (i.e.,
wavelengths less than 295 nm).
27b. Wavelengths between 295 nm and 300 nm are generally more biologically
effective (i.e., damage target molecules in the skin, including DNA)
than other wavelengths in UV-B and even more so than UV-A radiation.
27c. Latitudinal variations exist in solar radiation; model predictions
indicate that the greatest variability is seen in cumulative UV-B
(e.g., monthly doses) followed by peak UV-B (highest one-day doses)
and then cumulative UV-A. Peak UV-A does not vary significantly
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across latitudes up to 60°N. Greater ambient variation also exists
in UV-B than in UV-A by time of day.
27d. The biologically effective dose of radiation that actually reaches
target molecules depends on the duration of exposure at particular
locations, time of day, time of year, behavior (i.e., in terms of
clothes and sunscreens), pigmentation, and other characteristics of
the skin including temporal variations (e.g., changes in pigmentation
due to tanning).
21e. Cloudiness and albedo, although causing large variations in the
amount of exposure to UV-B and UV-A, do not greatly change the ratio
of UV-B to UV-A.
21f. Ozone depletion is predicted to cause the largest increases in
radiation in the 295-299 nm UV-B range, less in the 300-320 nm UV-B
range; UV-A is virtually unaffected by ozone depletion.
27g. Cutaneous malignant melanoma has a number of different histologic
types that vary in their relationship to sunlight, site, racial
preference, and possibly in their precursor lesions. Assessment of
incidence by types is not consistent among registries, thus
complicating attempts to evaluate the relationship between CMM and
solar radiation.
27h. Melanin is the principal pigment in skin that gives it color; melanin
effectively absorbs UV radiation; the darker the skin, the more the
basal layer is protected from UV radiation.
28. A LARGE ARRAY OF EVIDENCE SUPPORTS THE CONCLUSION THAT SOLAR RADIATION IS
ONE OF THE CAUSES OF CUTANEOUS MALIGNANT MELANOMA (chapter 8).
28a. Whites, whose skin contains less protective melanin, have higher
incidence and mortality rates from CMM than do blacks.
28b. Light-skinned whites, including those who are unable to tan or who
tan poorly, have a higher incidence of CMM than do darker-skinned
whites.
28c. Sun exposure leading to sunburn apparently induces melanocytic nevi.
28d. Individuals who have more melanocytic nevi have a higher incidence of
CMM; the greatest risk is associated with a particular type of nevus
-- the dysplastic nevus.
28e. Sunlight induces freckling, and freckling is an important risk factor
for CMM.
28f. Incidence has been increasing in cohorts in a manner consistent with
changes in patterns of sun exposure, particularly with respect to
increasing intermittent exposure of certain anatomical sites.
28g. Immigrants who move to sunnier climates have higher rates of CMM than
populations who remain in their country of origin. Immigrants
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develop rates approaching chose of prior (but native born) immigrants
to the adopted country; this is particularly accentuated in
individuals arriving before the age of puberty (10-14 years).
28h. It has been suggested that CMM risk may be associated with childhood
sunburn; other evidence suggests that childhood sunburn may reflect
an individual's pigmentary characteristics or may be related to nevus
development, rather than being a separate risk factor.
28i. Most studies that have used- latitude as a surrogate for sunlight or
UV-B exposure have found an increase in the incidence or mortality of
CMM correlated to proximity "to the equator. A recent study of
incidence using measured UV-B and CMM survey data found a strong
relationship between UV-B and incidence of CMM. Another study that
used modeled UV-B data and an expanded database on mortality found a
strong UV-B/mortality relationship.
28j. One form of CMM, Hutchinson's melanotic freckle, appears almost
invariably on the chronically sun-damaged skin of older people.
29. SOME EVIDENCE CREATES UNCERTAINTY ABOUT THE RELATIONSHIP BETWEEN SOLAR
RADIATION AND CUTANEOUS MALIGNANT MELANOMA (chapter 8).
29a. Some ecologic epidemiology studies, primarily in Europe or close to
the equator, have failed to find a latitudinal gradient for CMM.
29b. Outdoor workers generally have lower incidence and mortality rates
for CMM than indoc. workers, which appears incompatible with a
hypothesis that cumulative dose from solar exposure causes CMM.
29c. Unlike basal cell and squamous cell carcinomas, most CMM occurs on
sites that are not habitually exposed to sunlight; this contrast
suggests that cumulative exposure to solar radiation or UV-B is not
solely responsible for variations in CMM.
30. UV-B RADIATION IS A LIKELY COMPONENT OF SOLAR RADIATION THAT CAUSES
CUTANEOUS MALIGNANT MELANOMA (CMM). EITHER THROUGH INITIATION OF TUMORS OR
THROUGH SUPPRESSION OF THE IMMUNE SYSTEM (chapter 8).
30a. Xeroderma pigmentosum patients who fail to repair UV-B-induced
pyrimidine dimers in their DNA have a 2,000-fold excess rate of CMM
by the time they are 20.
30b. UV-B is the most active part of the solar spectrum in the induction
of mutagenesis and transformation is vitro.
30c. UV-B is the most active part of the solar spectrum in the induction
orf carcinogenesis in experimental animals and is considered by most
to be a causative agent of nonmelanoma skin cancer in humans.
30d. UV-B is the most active portion of the solar spectrum in inducing
immunosuppression, which may have a role in melanoma development.
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30e. The limitations in the epidemiologic and experimental database leave
some doubt as to the effectiveness of UV-B wavelengths in causing
CMM.
31. WHILE UNCERTAINTY EXISTS. INCREASES IN THE INCIDENCE AND MORTALITY OF
CUTANEOUS MALIGNANT MELANOMA ARE LIKELY AS A RESULT OF OZONE DEPLETION.
WHILE MANY UNCERTAINTIES EXIST (E.G.. REGARDING ACTION SPECTRA. PEAK VERSUS
CUMULATIVE DOSE. ETC.) ABOUT THE NATURE OF THE RELATIONSHIP BETWEEN UV-B
AND MELANOMA. THE FACT THAT UV-B RADIATION VARIES ACROSS THE ENVIRONMENT IN
THE RANGE OF VARIATION EXPECTED FROM DEPLETION PROVIDES INFORMATION USUALLY
UNAVAILABLE TO RESEARCHERS MAKING QUANTITATIVE RISK ESTIMATES. THUS
ALTHOUGH IMPERFECT. EPIDEMIOLOGIC INFORMATION EXISTS TO ESTIMATE A RANGE OF
CHANGES IN INCIDENCE AND MORTALITY IF THE OZONE LAYER IS DEPLETED (chapter
8).
31a. Uncertainty exists about the appropriate action spectrum to be used
in estimating dose, the best functional form for dose-response, and
the best way to characterize dose (peak value, cumulative summer
exposure, etc.)- Histologically different CMMs (or possibly CMM
located at different anatomical sites) are likely to have different
dose-response relationships. Most estimates of CMM dose-response
relationships fail to consider these histological or site
differences. Nonetheless, by encompassing a range of possibilities,
it is possible to estimate dose-response because of the systematic
variations in UV-B.
31b. A recent study by the NIH presents a well-designed ecological study
of melanoma and UV-B using survey data and measured UV-B at ground
level. While uncertainties exist, this dose-response relationship,
when used with different action spectra and assumptions about the
importance of peak versus cumulative exposure, can be utilized to
estimate a range of values for cases. The relationship estimates
that a 1 percent change in ozone is likely to increase incidence by
between slightly less than 1 to 2 percent, depending on the choice of
action spectrum. The appropriate action spectrum is likely to be
encompassed in the range of erythema and DNA.
31c. Melanoma mortality is estimated at about 25 percent of all cases.
This result is consistent with the projections of a dose-response
model of mortality developed by EPA/NCI. It is estimated that a 1
percent change in ozone would result in between a 0.3 and a 2.0
percent change in CMM mortality depending on the assumptions about
the appropriate dose and UV weighting functions used in the model.
31d. Additional uncertainties for projecting future incidence and
mortality of CMM in the U.S. include the lack of an adequate database
describing variations ih skin pigmentation and human sun-exposure
behavior among different populations and estimates of how these
relationships may change in the future.
32. UV-B SUPPRESSES THE IMMUNE SYSTEM IN ANIMAL EXPERIMENTS (chapter 9).
32a. UV radiation administered at relatively low doses causes a depression
in local contact hypersensitivity (a form of cell-mediated immunity)
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resulting from an inability to respond to an antigen presented
through UV-irradiated skin.
32b. High doses of UV radiation cause a depression in systemic contact and
delayed type hypersensitivity reactions, that result in an inability
of the animal to respond to an antigen which is presented to the
animal through unirradiated skin.
32c. Both the local and systemic effects on contact hypersensitivity are
mediated by a T suppressor, -cell which prevents the development of
active immunity to the antigen.
32d. The immunosuppressive effects of ultraviolet radiation (UVR) have
been found to reside almost entirely in the UV-B portion of the
ground level solar radiation.
33. SUPPRESSION OF .THE IMMUNE SYSTEM MAY PLAY AN IMPORTANT ROLE IN
CARCINOGENESIS (chapter 9). .
33a. Animals which are UV-irradiated develop T suppressor cells which
interfere with the immune response to UV-induced tumors in such a way
that the animals are more susceptible to the growth of autochthonous
UV-induced tumors. The contribution of the suppression of the immune
system to cancer incidence that would result from ozone depletion is
reflected in the dose-response estimates of photocarcinogenesis
assuming that the action spectra for the two phenomena are the same.
If these two impacts have different action spectra, the estimates
could be either high or low.
34. LIMITED EXPERIMENTAL DATA INDICATE UV-B SUPPRESSES THE HUMAN IMMUNE SYSTEM
(chapter 9).
34a. Although there is limited information about the effects of UV
radiation on humans, several studies indicate that the immune
response of humans is depressed by UV radiation and is depressed in
UV-irradiated skin.
35. UV-B-INDUCED SUPPRESSION OF THE HUMAN IMMUNE SYSTEM COULD HAVE A
DELETERIOUS EFFECT WITH REGARD TO MANY HUMAN DISEASES (chapter 9).
3Sa. Preliminary studies indicate that UV radiation may prevent an
effective immune response to micro-organisms that infect via the
skin, thus predisposing to reexpression or chronic infection.
35b. Two human diseases that may be influenced by UV-B-induced immune
suppression are herpes virus infections and leishmaniasis.
35c. Almost no research has been conducted on the influence of UV-B on
other infectious diseases; additional investigation is clearly
warranted.
35d. For at least one theory of the mechanisms of UV-B-induced suppression
of the immune system (that involving urocanic acid), a possibility
exists that non-whites, as well as whites, would be vulnerable to
increased immune suppression caused by ozone depletion.
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35e. Because UV-B can produce systemic immunologic change, Che possibility
exists that changes in UV-B could have resulted in effects on
diseases whose control requires systemic rather than local immunity.
35f. Immunologic studies to date have not assessed the effects of long-
term, low-dose UV-B irradiation. Consequently, the magnitude of this
risk cannot be assessed.
36. EVIDENCE EXISTS SUGGESTING THAT CATARACT INCIDENCE WILL CHANGE WITH
ALTERATIONS IN THE FLUX OF UV-B CAUSED BY OZONE DEPLETION (chapter 10).
36a. Many possible mechanisms exist for formation of cataracts. UV-B may
play an important role in some mechanisms.
36b. Although the cornea and aqueous humor of the human eye screen out
significant amounts of UV-A and UV-B radiation, nearly 50 percent of
radiation at 320 nm is transmitted to the lens. Transmittance
declines substantially below 320 nm, so that less than 1 percent is
transmitted below approximately 290 to 300 nm. However, the results
of laboratory experiments on animals indicate that short wavelength
UV-B (i.e., below 290 nm) is perhaps 250 times more effective than
long wavelength UV-B (i.e., 320 nm) in inducing cataracts.
36c. Human cataract prevalence varies with latitude and UV radiation;
brunescent nuclear cataracts show the strongest relationship.
37. INCREASES IN THE AMOUNT OF UV-B THAT CAN REACH THE RETINA APPEAR CAPABLE OF
CAUSING STABLE RETINAL DISORDERS AND RETINAL DEGENERATION. TWO CAUSES OF
BLINDNESS (chapter 10).
38. LIMITED STUDIES ANALYZING THE EFFECT OF INCREASED UV-B RADIATION ON CROPS
GENERALLY SHOW ADVERSE IMPACTS. HOWEVER. CONCLUSIONS ABOUT THE AMOUNT OF
YIELD LOSSES ATTRIBUTABLE TO UV-B CANNOT BE DRAWN (chapter 11).
38a. Difficulties in experimental design, the large number of species and
cultivars, and complex interactions between plants and their
environment have prevented quantification of total crop loss from
increases in UV-B.
38b. Action spectra for UV damage to higher plants are limited, but
indicate a strong weighting toward shorter UV-B wavelengths which are
those most affected by ozone reduction.
39. OF PLANT CULTIVARS TESTED IN THE LABORATORY. APPROXIMATELY 70 PERCENT WERE
DETERMINED TO BE SENSITIVE TO UV-B: CARE MUST BE TAKEN IN INTERPRETING THIS
FINDING (chapter 11).
39a. Different cultivars within a species have exhibited different degrees
of UV-B sensitivity. While this suggests selective breeding could
limit damage, neither the basis for selectivity nor the potential
effect on other aspects of growth has been studied.
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39b. Laboratory experiments have been shown to inadequately replicate
effects in the field, thus the implications of cultivar sensitivity
are not certain.
39c. In some species, mitigation responses more readily apparent in the
field (e.g., increased production of UV absorbing flavonoids) have
reduced adverse impacts.
40. THE EFFECTS OF UV-B RADIATION HAVE BEEN EXAMINED FOR ONLY FOUR OF THE TEN
MAJOR TERRESTRIAL ECOSYSTEMS AND FOR ONLY A THIRD OF THE PLANT GROWTH FORMS
(chapter 11).
40a. Little or no data exist on enhanced UV-B effects on trees, woody
shrubs, vines, or lower vascular plants.
41. LARGE UNCERTAINTIES EXIST AS A RESULT OF AN IMPERFECT EXPERIMENTAL DESIGN
OR DOSIMETRY. EXISTING EXPERIMENTAL FIELD DATA SUGGEST A POTENTIAL
REDUCTION IN CROP YIELD FOR SOME CROPS DUE TO ENHANCED UV-B RADIATION
(chapter 11).
41a. Field experiments in which UV-B radiation has been supplemented are
limited. Several of the earlier field experiments are of limited
value since UV-B doses or other factors such as soil temperature were
not sufficiently controlled or representative of field conditions.
Dose-response studies in the field are particularly different.
41b. The only long-term field studies of a crop involved soybeans. These
studies have found that enhanced levels of UV-B, simulating between
16 and 25 percent ozone depletion, caused crop yield reductions of up
to 25 percent in a particular cultivar. Smaller reductions in yield
were experienced in years where drought conditions existed.
41c. Soybean (CV Essex) yield could be accurately predicted when total
UV-B dose, daily maximum temperature, and number of days of
precipitation were included in a regression model.
41d. The lipid and protein content of soybean was reduced up to 10
percent; however, higher UV-B doses alone did not consistently result
in the largest reductions.
41e. While only several cultivars have been tested in the field, two out
of three soybean cultivars tested under laboratory conditions were
sensitive to UV-B. If this relationship holds true in the field, it
suggests (when considered in light of yield reduction experiments)
that UV-B increases could harm the potential of the world
agricultural system to produce soybeans.
42. THE EFFECTS OF UV-B ON FUNGAL OR VIRAL PATHOGENS VARY WITH PATHOGEN. PLANT
SPECIES. AND CULTIVAR (chapter 11).
42a. Current evidence on possible interactions with pathogens is very
limited.
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42b. Reduced vigor in UV-sensitive plants could render the plants more or
less susceptible to pest or disease damage and thus result in changes
in crop yield.
43. CHANGES IN UV-B LEVELS MAY INDUCE SHIFTS IN INTERSPECIFIC COMPETITION
(chapter 11).
43a. If enhanced UV-B favors weeds over crops, agricultural costs (e.g.,
for increased tilling and herbicide application) could increase.
However, insufficient evidence exists to form a basis for evaluating
this effect.
43b. Increases in UV-B could alter the results of the competition in
natural ecosystems and thus shift community composition. Since UV-B
changes would be both global and long term, possible UV-induced
alterations of plant species balances could result in large-scale
changes in the character and equilibrium of vegetation in
nonagricultural areas such as forests and grasslands.
44. UV-B RADIATION INHIBITS AND STIMULATES FLOWERING. DEPENDING ON THE SPECIES
AND GROWTH CONDITIONS (chapter 11).
44a. The timing of flowering may also be influenced by UV-B radiation, and
there is limited evidence that pollen may be susceptible to UV damage
upon germination.
44b. Reproductive structures enclosed within the ovary appear to be
well-protected from UV-B radiation.
45. INTERACTIONS BETWEEN UV-B RADIATION AND OTHER ENVIRONMENTAL FACTORS ARE
IMPORTANT IN DETERMINING POTENTIAL UV-B EFFECTS ON PLANTS (chapter 11).
45a. UV-B effects may be worsened under low light regimes or less apparent
under conditions of limited nutrients or water.
45b. Interactions with other environmental effects make extrapolation of
data from growth chambers or greenhouses to field conditions
difficult and often unreliable.
45c. The combined effect of higher UV-B and other environmental changes
cannot be adequately assessed by current data. Extensive, long-term
studies would be required.
46. INITIAL EXPERIMENTS SHOW THAT REDUCTIONS IN STRATOSPHERIC OZONE. WHICH
INCREASES SOLAR ULTRAVIOLET RADIATION. HAVE THE POTENTIAL TO HARM AQUATIC
LIFE. DIFFICULTIES IN EXPERIMENTAL DESIGNS AND THE LIMITED SCOPE OF THE
STUDIES PREVENT THE QUANTIFICATION OF RISKS (chapter 12).
46a. Increases in energy in the 290-320 nm wavelengths that would occur if
the ozone layer were depleted could harm aquatic life.
46b. Various experiments have shown that UV-B radiation damages fish
larvae and juveniles, shrimp larvae, crab larvae, copepods, and
plants essential to the marine food web.
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46c. Up to some threshold level of exposure, most zooplankton show no
effect due to increased exposure to UV-B radiation. However,
exposure above the dose threshold elicits significant and
irreversible physiological and behavioral effects.
*
46d. While the exact limits of tolerance and current exposure have not
been precisely determined, estimates of these two properties for a
variety of aquatic organisms show them to be essentially equal.
46e. The equality of tolerance and exposure suggests that solar UV-B
radiation is currently an important limiting ecological factor, and
the sunlight-exposed organisms sacrifice potential resources to avoid
increased UV-B exposure. Thus, even small increases of UV-B exposure
would be likely to further injure species currently under UV-B
stress.
46f. A decrease in column ozone is reasonably likely to diminish the time
that zooplankton can survive or breed at or near the surface of
waters they inhabit. For some zooplankton, the time they spend at or
near the surface is critical for breeding. Whether the population
could endure a significant shortening of surface time is unknown.
46g. Sublethal exposure of copepods produces a reduction in fecundity.
46h. Of the animals tested, no zooplankton possess a sensory mechanism for
directly detecting UV-B radiation; therefore, it would be unlikely
that they would actively-*iv-oid enhanced levels of exposure resulting
from a reduction in column ozone.
46i. Exposure of a community to UV-B stress in controlled experiments has
resulted in a decrease in species diversity, and therefore a possible
reduction in ecosystem resilience and flexibility.
46j. One experiment predicted an 8 percent annual loss of the larval
anchovy population from a 9 percent reduction in column ozone in a
marine system with a 10-meter mixed layer.
47. IN COMMON WITH ALL OTHER LIVING ORGANISMS. THE AQUATIC BIOTA COPE WITH
SOLAR UV-B RADIATION BY AVOIDANCE. SHIELDING. AND REPAIR MECHANISMS.
UNCERTAINTY EXISTS AS TO THE EXTENT TO WHICH SUCH MITIGATION MECHANISMS
WOULD OCCUR (chapter 12).
48. DETERMINATION OF UV-B EXPOSURE IN AQUATIC SYSTEMS IS COMPLEX BECAUSE OF THE
VARIABLE ATTENUATION OF UV-B RADIATION IN THE WATER COLUMN (chapter 12).
48a. Because aquatic organisms are small and do not usually have fixed
locations, it is very difficult to obtain accurate data needed to
model the systems and verify results. Current understanding of the
life cycle of organisms is very limited.
49. ABOUT ONE HALF OF THE WORLD'S PROTEIN IS DERIVED FROM MARINE SPECIES. IN
MANY THIRD WORLD COUNTRIES. THIS PERCENTAGE IS LARGER. RESEARCH IS NEEDED
TO IMPROVE OUR UNDERSTANDING OF HOW OZONE DEPLETION COULD INFLUENCE THESE
SYSTEMS (chapter 12).
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49a. A comprehensive analysis of sublethal and lethal effects of solar UV
on littoral, benthos, and planktonic ecosystems is needed.
49b. A model of energy flow analysis leading to protein production where
solar input is augmented by increased ultraviolet radiation would be
required to better evaluate potential effects. Marine organisms
responses to projected increases in UV must be considered in the
context of the oceans as a dynamic moving fluid.
49c. Better documentation of the effects of present levels of ultraviolet
light on marine organisms is needed.
49d, Intensive research is needed to identify biochemical indices that
reflect UV stress in marine organisms.
50. INCREASED UV-B RADIATION WILL ACCELERATE THE DEGRADATION OF POLYMERS
(chapter 13).
50a. Several commercial polymers (e.g., polyethylene, polypropylene,
poly(vinylchloride)), although theoretically UV transparent, contain
chromophore impurities that absorb light in the UV-B region of the
spectrum. Other polymers (e.g., polycarbonate) have structural
features in their molecules that result in strong UV-B light
absorption.
50b. Several polymers have important outdoor applications (e.g., used in
siding and window glazing in the building industry, in film and
containers in packaging, in housewares and toys, and in paints and
protective coatings). Such polymers are likely to be exposed to
significant amounts of UV-B radiation. Other polymers are stored
outside before use and could deteriorate during these periods.
50c. Absorption of UV-B radiation in polymers causes photo-induced
reactions and alters important mechanical, physical, or optical
properties of the polymers (e.g., yellowing, brittleness) and thus
degrades (i.e., reduces the useful life of) the polymers.
51. INCREASED USE OF UV-STABILIZERS FOR PROTECTION OF POLYMERS AGAINST UV
RADIATION WOULD HAVE NEGATIVE EFFECTS (chapter 13).
51a. Increased amounts of stabilizers might adversely affect the
processing and use properties of some polymers (e.g., hardness,
thermal conductivity, flow characteristics). For example, increased
amounts of titanium dioxide in poly(vinylchloride) might affect its
processing properties, increasing its costs of production.
51b. Changes in the amount of stabilizer (and other additives) would
increase costs of products. Alternatively, manufacturers could
develop new formulations to avoid or minimize impurities in
production.
51c. The addition of stabilizers to polymers may be limited by practical
problems of material characteristics or manufacture. However, other
responses may be possible to limit damage.
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52. INCREASED UV-B RADIATION DUE TO OZONE DEPLETION COULD HAVE ADVERSE ECONOMIC •
EFFECTS (chapter 13).
52a. Changes in polymer processing properties can result in more equipment
shutdowns, higher maintenance costs, and increased utility costs.
52b. Increased operating costs and material costs (e.g., for stabilizers,
lubricants, and other additives) would have an adverse economic
impact on the polymer/plastic and related industries.
52c. In a case study using preliminary data and methods, and a given
scenario of ozone depletion (26% depletion by 2075), undiscounted
cumulative (1984-2075) economic damage for poly(vinylchloride) is
estimated at $4.7 billion (USA only). Due to the lack of data,
possible damage to other polymers has not been assessed.
53. POTENTIAL DAMAGES TO POLYMERS RELATED TO OZONE DEPLETION AND CLIMATE CHANGE
ARE DIFFICULT TO ESTIMATE (chapter 13).
53a. Due to lack of relevant experimental data, only approximate
estimation methods are available to determine the potential extent of.
light-induced damage to polymers and other materials.
53b. Depending upon the chemical nature of a polymer, the components of
the compound, and the weathering factors, both temperature and
humidity tend to increase the rate of degradation.
53c. Research on dose-response relationships for polymers could increase
our ability to project the effects of ozone depletion.
53d. Actual action spectra need to be developed for different polymers.
53e. The feasibility of different mitigation measures needs to be
experimentally determined.
53f. The synergistic effects of increased humidity and temperature need to
be considered.
54. RESULTS FROM ONE MODELING STUDY AND ONE CHAMBER STUDY SUGGEST THAT
INCREASED ULTRAVIOLET RADIATION FROM OZONE DEPLETION MAY INCREASE THE RATE
OF TROPOSPHERIC OZONE FORMATION (chapter 14).
54a. According to these studies, increases in UV-B associated with ozone
depletion would increase the quantity of ground-based ozone
associated with various hydrocarbon and nitrogen oxides emission
levels. Results for individual cities vary, depending on the city's
* location and on the exact nature of the pollution.
54b. According to these studies, global warming would enhance the effects
of increased UV-B radiation on the formation of ground-based ozone.
54c. According to these studies, ground-based ozone would form closer to
urban centers. This would cause larger populations in some cities to
be exposed to peak values.
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54d. More research is needed to verify and expand the results of these
initial studies.
55. PRELIMINARY RESULTS FROM ONE STUDY ALSO SUGGEST THAT LARGE INCREASES IN
HYDROGEN PEROXIDE WOULD RESULT FROM INCREASED UV-B RADIATION (chapter 14):
55a. If hydrogen peroxide increases as predicted in this study, the
oxidizing capability potential of the atmosphere, including the
formation of acid rain, would be influenced.
55b. More research, especially a chamber study, is needed to verify this
effect.
56. INCREASES IN GROUND-BASED OZONE WOULD ADVERSELY AFFECT PUBLIC HEALTH AND
WELFARE (chapter 14).
56a. If UV-B increases enhanced ozone production, more U.S. cities would
be unable to meet health-based ground-level ozone standards, and
background ozone would increase.
56b. Crops, ecosystems, and materials would be adversely affected by
increased ground-level ozone.
57. THE PROJECTED GLOBAL WARMING WOULD ACCELERATE THE CURRENT RATE OF SEA LEVEL
RISE BY EXPANDING THE DENSITY OF OflAN WATER. MELTING ALPINE GLACIERS. AND
EVENTUALLY INCREASING THE RATE" AT WHICH POLAR ICE SHEETS MELT OR DISCHARGE
ICE INTO THE OCEANS (chapter 15).
58. GLOBAL AVERAGE SEA LEVEL APPEARS TO HAVE RISEN 10 TO 15 CM OVER THE LAST
CENTURY (chapter 15).
58a. Studies of the possible contribution of thermal expansion and alpine
meltwater to sea level rise, based on the 0.6°C warming of the past
century, indicate that these two sources are insufficient to explain
the estimated sea level rise that has occurred during this period.
Consequently, some other source, such as melting of the polar ice
caps, must be considered a possibility.
59. ESTIMATES OF THE RISE IN SEA LEVEL THAT COULD TAKE PLACE IF MEASURES TO
LIMIT THE GLOBAL WARMING ARE NOT UNDERTAKEN RANGE FROM 10 TO 20 CM BY THE
YEAR 2025. AND 50 TO 200 CM BY 2100 (chapter 15)
59a. According to published studies, thermal expansion of the oceans alone
would increase sea level rise between about 30 cm and 100 cm by 2100,
depending on the realized temperature change. This is the most
certain contribution.
59b. Melting of alpine glaciers and possibly of ice on Greenland could
each contribute 10 to 30 cm through 2100, depending on the scenario.
This contribution also has a high degree of likelihood.
59c. The contribution of Antarctic deglaciation is more difficult to
project. It has been estimated at between 0 and 100 cm; however, the
possibilities cannot be ruled out that (1) increased snowfall could
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increase the size of the Antarctic ice sheet and thereby partially
offset part of the sea level rise from other sources; or (2)
meltwater and enhanced calving of the ice sheet could increase the
contribution of Antarctic deglaciation to as much as 2 m. The
Antarctic contribution to sea level rise may be more sensitive to
time delays after certain threshold conditions are reached than to
the magnitude of total wanning.
60. OVER THE MUCH LONGER TERM (THE NEXT FEW CENTURIES) DISINTEGRATION OF THE
WEST ANTARCTIC ICE SHEET MIGHT RAISE SEA LEVEL BY 6 METERS (chapter 15).
60a. If a disintegration takes place, glaciologists generally believe that
such a complete disintegration of the west Antarctic ice sheet would
take at least 300 years, and probably at least 500 years.
60b. A global warming might result in sufficient thinning of the Ross and
Filcher-Ronne Ice Shelves in the next century to make the process of
disintegration irreversible.
61. LOCAL TRENDS IN SUBSIDENCE AND EMERGENCE MUST BE ADDED OR SUBTRACTED TO
GLOBAL RISK ESTIMATES IN ORDER TO ESTIMATE RELATIVE SEA LEVEL RISE AT
PARTICULAR LOCATIONS (chapter 15).
61a. Host of the Atlantic and Gulf Coasts of the United States — as well as
the Southern Pacific coast--are subsiding 10-20 cm per century.
61b. Louisiana is subsiding 1 m per century, while parts of Alaska are
emerging 10-150 cm per century. —
61c. Due to subsidence already occurring in areas such as Bangladesh,
Bangkok, and the Nile-delta, these areas are extremely vulnerable to
sea level rise.
62. A SUBSTANTIAL RISE IN SEA LEVEL WOULD PERMANENTLY INUNDATE WETLANDS AND
LOWLANDS. ACCELERATE COASTAL EROSION. EXACERBATE COASTAL FLOODING. AND
INCREASE THE SALINITY OF ESTUARIES AND AQUIFERS (chapter 15).
62a. Louisiana is the state most vulnerable to a rise in sea level.
Important impacts would also occur in Florida, Maryland, Delaware,
New Jersey, and in the coastal regions of other states.
62b. A rise in sea level of 1 to 2 m by the year 2100 could destroy 50
percent to 80 percent of U.S. coastal wetlands.
62c. Limited studies predict that increased salinity from sea level rise
would convert cypress swamps to open water and threaten drinking
water supplies in areas such as Louisiana, Philadelphia, and New
Jersey. Other areas, such as Southern Florida, may also be
vulnerable but have not been investigated.
62d. Studies of Bangladesh and the Nile River Delta indicate that these
river deltas, which are already subsiding, would be greatly affected
by rising sea level, experiencing significant economic and
environmental losses.
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63. EROSION PROJECTED IN VARIOUS STUDIES TO RESULT FROM ACCELERATED SEA LEVEL
RISE COULD THREATEN U.S. RECREATIONAL BEACHES (chapter 15).
63a. Case studies of beaches in New Jersey, Maryland, California, South
Carolina, and Florida have concluded that a 30-cm rise in sea level
would result in beaches eroding 20-60 m or more. Major beach
preservation efforts would be required if recreational beaches are to
be maintained.
64. ACCELERATED SEA LEVEL RISE WOULD INCREASE THE DAMAGES FROM FLOODING IN
COASTAL AREAS (chapter 15).
64a. Flood damages would increase because higher water levels would
provide a higher base for storm surges.
64b. Erosion would increase the vulnerability to storm waves, and
decreased natural and artificial drainage would increase flooding
during rainstorms.
65. ESTIMATES OF DAMAGE FROM SEA LEVEL RISE MUST CONSIDER POSSIBLE MITIGATION
BY HUMAN RESPONSES (chapter 15).
65a. The adverse impacts of sea level rise could be ameliorated through
anticipatory land use planning and structural design changes.
65b. In a case study of two cities, Charleston, South Carolina, and
Galveston, Texas, accelerated anticipatory planning was estimated to
reduce net damages by 20 to 60 percent.
66. RELATED IMPACTS OF A GLOBAL WARMING WOULD ALSO AFFECT IMPACTS OF SEA LEVEL
RISE (chapter 15.).
66a. Increased droughts might amplify the salinity impacts of sea level
rise.
66b. Increased hurricanes and increased rainfall in coastal areas could
amplify flooding from sea level rise.
66c. Warmer temperatures might impair peat formation of salt marshes and
would enable mangrove swamps to take over areas that are presently
salt marsh.
66d. Decreased northeasters might reduce damage.
67. RESEARCH OPPORTUNITIES EXIST TO IMPROVE SEA LEVEL RISE ESTIMATES AND
IMPACTS (chapter 15).
67a. The most critical areas of research for reducing the variation in
estimates of future sea level rise are ice melting and runoff in
Antarctica and Greenland and ice discharge.
67b. Research in glacial discharge in Antarctica should focus not just on
West Antarctica, but on Pine Island and East Antarctica.
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67c. An improved program of tidal gauge stations, especially in the
southern hemisphere, and satellite altimetry should be used to
measure sea level rise and the mass balance of ice sheets.
68. CLIMATE CHANGE HAS HAD A SIGNIFICANT IMPACT ON FORESTS IN THE PAST. IF
CURRENT PREDICTIONS PROVE ACCURATE. THERE IS A POTENTIAL FOR DRAMATIC
SHIFTS IN FORESTS AND VEGETATION OVER THE NEXT 100 YEARS (chapter 16).4
68a. Climate models predict that a global warming of approximately 1.5°C
to 4.5°C will be induced by a doubling of atmospheric C02 and other
trace gases during the next 50 to 100 years. The period 18,000 to 0
years B.P. is the only general analog for a global climate change of
this magnitude. The geological record from this glacial to
inter-glacial interval provides a basis for qualitatively
understanding how vegetation may change in response to large climatic
change.
68b. The paleovegetational record shows that climatic change as large as
that expected to occur in response to C02 doubling is likely to
induce significant changes in the composition and patterns of the
world's biomes. Change's of 2°C to 4°C have been significant enough
to alter the composition of biomes, and to cause new biomes to appear
and others to disappear. At 18,000 B.P., the vegetation in eastern
North America was quite distinct from that of the present day. The
cold, dry climate of that time seems to have precluded the widespread
growth of birch, hemlock, beech, alder, hornbeam, ash, elm, and
chestnut, all of which are fairly abundant in pL3sent-day deciduous
forest. Southern pines were limited to grow with oak and hickory in
Florida.
68c. Available paleoecological and paleoclimatological records do not
provide an analog for the high rate of climate change and
unprecedented global warming predicted to occur over the next
century. Previous changes in vegetation have been associated with
climates that were nearly 5°C to 7°C cooler and took thousands of
years to evolve rather than decades, the time during which such
changes are now predicted to occur. Insufficient temporal resolution
(e.g., via radiocarbon dates) limits our ability to analyze the
decadal-scale rates of change that occurred prior to the present
millennium.
68d. Limited experiments conducted with dynamic vegetation models for
North America suggest that decreases in net biomass may occur and
that significant changes in species composition are likely.
Experiments with one model suggest that eastern North American
biomass may be reduced by 11 megagrams per hectare (10% of live
biomass) given the equivalent of a doubled C02 environment. Plant
taxa will respond individualistically rather than as whole
communities to regional changes in climate variables. At this time
such analyses must be treated as only suggestive of the kinds of
4 Findings 68 to 71 are summarized from Appendix B, which provides a
comprehensive review of potential impacts of global climate change.
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change that could occur. Many critical processes are simplified or
omitted and the actual situation could be worse or better.
68e. Future forest management decisions in major timber-growing regions
are likely to be affected by changes in natural growing conditions.
For example, one study suggests that loblolly pine populations are
likely to move north and northeast into Pennsylvania and New Jersey,
while its range shrinks in the west. The total geographic range of
the species may increase, but a net loss in productivity may result
because of shifts to less accessible and less productive sites.
While the extent of such changes is unclear, adjustments will be
needed in forest technology, resource allocation, planning, tree
breeding programs, and decision-making to maintain and increase
productivity.
68f. Dynamic vegetation models based on theoretical descriptions of all
factors that could influence plant growth must be improved and/or
developed for all major kinds of vegetation. In order to make more
accurate future predictions, these models must be validated using the
geological record and empirical ecological response surfaces. In
particular, the geological record can be used to test the ability of
vegetation models to simulate vegetation that grew under climate
conditions unlike any of the modern day conditions.
68g. Dynamic vegetation models should incorporate direct effects of
atmospheric C02 increases on plant growth and other air pollution
effects. Improved estimates of futur" regional climates are also
required in order to make accurate predictions of future vegetation
changes.
69. LIMITED ASSESSMENTS SUGGEST THAT IMPORTANT CHANGES IN AGRICULTURE AND FARM
PRODUCTIVITY ARE LIKELY THROUGHOUT THE WORLD IF CLIMATE CHANGE OCCURS AS
PREDICTED. ESTIMATES OF IMPACTS ON SPECIFIC REGIONS ARE DIFFICULT TO MAKE
BECAUSE REGIONAL PROJECTIONS OF CHANGE CANNOT BE RELIABLY MADE. CURRENT
CLIMATIC KNOWLEDGE IS ONLY SUFFICIENT TO SUPPORT VULNERABILITY STUDIES FOR
ALTERNATIVE SCENARIOS (chapter 16).
69a. Climate has had a significant impact on farm productivity and
geographical distribution of crops. Examples include the 1983
drought, which contributed to a nearly 30 percent reduction in corn
yields in the U.S.; the persistent Great Plains drought between
1932-1937, which contributed to nearly 200,000 farm bankruptcies; and
the climate shift of the Little Ice Age (1500-1800), which led to the
abandonment of agricultural settlements in Scotland and Norway.
69b. World agriculture is likely to undergo significant shifts if
trace-gas-induced climate warming in the range of 1.5°C to 4.5°C
occurs over the next 50 to 100 years. Climatic effects on
agriculture will extend from local to regional and international
levels. However, modern agriculture is very dynamic and is
constantly responding to changes in production, marketing, and
government programs.
69c. The main effects likely to occur at: the field level will be physical
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ES-51
impacts of changes in thermal regimes, water conditions, and pest
infestations. High temperatures have caused direct damage to crops
such as wheat and corn; moisture stress, often associated with
elevated temperatures, is harmful to corn, soybean, and wheat .during
flowering and grain fill; and increased pests are associated with
higher, more favorable temperatures.
69d. Even relatively small increases in the mean temperature can increase
the probability of harmful effects in some regions. Analysis of
historical data has shown that an increase of 1.7°C (3°F) in mean
temperature changes by about a factor of three the likelihood of a
five-consecutive-day maximum.temperature event of at least 35°C
(95°F) occurring in a city like Des Moines. In regions where crops
are grown close to their maximum tolerance limits, extreme
temperature events may have significant harmful effects on crop
growth and yield.
69e. Limited experiments using climate scenarios and agricultural
productivity models have demonstrated the sensitivity of agricultural
systems to climate change. Future farm yields are likely to be
affected by climate because of changes in the length of the growing
season, heating units, extreme winter temperatures, precipitation,
and evaporative demand. In addition, field evaluations show that
total productivity is a function of the drought tolerance of the land
and the moisture reserve, the availability of land, the ability of
farmers to shift to different crops, and other factors.
69f. The transition costs associated with adjusting, to global climatic
change are not easily calculated, but are likely to be very large.
Accommodating to climate change may require shifting to new lands and
crops, creating support services and industries, improving and
relocating irrigation systems, developing new soil management and
pest control programs, and breeding and introducing new heat- or
drotight-tolerant species. The consequences of these decisions on the
total quantity, quality, and cost of food are difficult to predict.
69g. Current projections of the effects of climate change on agriculture
are limited because of uncertainties in predicting local temperature
and precipitation patterns using global climate models, and because
of the need for improved research studies using controlled
atmospheres, statistical regression models, dynamic crop models and
integrated modeling approaches.
70. WATER RESOURCE SYSTEMS HAVE UNDERGONE IMPORTANT CHANGES AS THE EARTH'S
CLIMATE HAS SHIFTED IN THE PAST. CURRENT ANALYSES SUGGEST AN INTENSIFIED
HYDROLOGIC CYCLE. IF CLIMATE CHANGE OCCURS AS PREDICTED (chapter 16).
70a. There is evidence that climate change since the last ice age (18,000
years B.P.) has significantly altered the location of lakes --
although the extent of present day lakes is broadly comparable with
18,000 years B.P. For example, there is evidence indicating the
existence of many tropical lakes and swamps in the Sahara, Arabian,
and Thor Deserts around 9,000 .to 8,000 years B.P.
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70b. The inextricable linkages between the water cycle and climate ensure
that potential future climate change will significantly alter
hydrologic processes throughout the world. All natural hydrologic
processes--precipitation, infiltration, storage and movement of soil
moisture, surface and subsurface runoff, recharge of groundwater, and
evapotranspiration--will be "affected if climate changes.
70c. As a result of changes in key hydrologic variables such as
precipitation, evaporation, soil moisture, and runoff, climate change
is expected to have significant effects on water availability. Early
hydrologic impact studies provide evidence that relatively small
changes in precipitation and evaporation patterns might result in
significant, perhaps critical, changes in water availability. For
many aspects of water resources, including human consumption,
agricultural water supply, flooding and drought management,
groundwater use and recharge, and reservoir design and operation,
these hydrologic changes will have serious implications.
70d. Despite significant differences among climate change scenarios, a
consistent finding among hydrologic impact studies is the prediction
of a reduction in summer soil moisture and changes in the timing and
magnitude of runoff. Winter runoff is expected to increase and
summer runoff to decrease. These results appear to be robust across
a range of climate change scenarios.
70e. Future directions for research and analyses suggest that improved
estimates of climate variables are needed from lr-ge-scale climate
models; innovative techniques are needed for regional assessments;
increased numbers of assessments are necessary to broaden our
knowledge of effects on different users; and increased analyses of
the impacts of changes in water resources on the economy and society
are necessary.
71. MORBIDITY AND MORTALITY RATES ARE ASSOCIATED WITH WEATHER EXTREMES IN OUR
SOCIETY (chapter 16).
71a. Weather has a profound effect on human health and well being. It has
been demonstrated that weather is associated with changes in birth
rates, outbreaks of pneumonia, influenza, and bronchitis, and related
to other morbidity effects, and is linked to pollen concentrations
and high pollution levels.
71b. Large increases in mortality have occurred during previous heat and
cold waves. It is estimated that 1,327 fatalities occurred in the
United States as a result of the 1980 heat wave, and Missouri alone
accounted for over 25 percent of that total.
«•
71c. Hot weather extremes appear to have a more substantial impact on
mortality than cold wave episodes.
71d. Threshold temperatures, which represent maximum and minimum
temperatures associated with increases in total mortality, have been
determined for various cities. These threshold temperatures vary
regionally; for example, the threshold temperature for winter
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ES-53
mortality in mild southern cities such as Atlanta is 0°C and for more
northerly cities such as Philadelphia, threshold temperature is -5°C.
71e. If future global warming induced by increased concentrations of trace
gases does occur, it has the potential to affect human mortality
significantly. In one study, total summertime mortality in New York
City was estimated to increase by over 3,200 deaths per year for a
7°F trace-gas-induced warming without acclimatization. If New
Yorkers fully acclimatize, the number of additional deaths is
estimated to be no different than today. It is hypothesized that if
climate warming occurs, some additional deaths are likely to occur
because economic conditions and the basic infrastructure of the city
will prohibit full acclimatization even if behavior changes.
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QUANTITATIVE ASSESSMENT OF RISKS WITH INTEGRATED MODEL
AN INTEGRATED ASSESSMENT OF RISKS FOR VARIOUS SCENARIOS OF OZONE-DEPLETING
SUBSTANCES SHOWS THAT HARM DEPENDS ON THE LEVEL OF THE PRODUCTION OF CHLORINE
AND BROMINE BEARING SUBSTANCES.
Risks are evaluated by using the integrated model to simulate the impact of
"what-if" scenarios of production of ozone-depleting substances and scenarios of
other trace gas concentrations on the atmosphere and on l.jman health and the
environment. Sensitivity analyses of alternative assumptions are also
conducted.
Analysis of the results of all the scenarios indicates that adverse impacts
on health and welfare are lowered with reductions in the production of ozone-
depleting substances.
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72. MODIFICATION OF THE TRACE GAS COMPOSITION OF THE ATMOSPHERE CAN BE EXPECTED
TO ALTER COLUMN OZONE ABUNDANCE (chapter 18).
72a. The range of global average total column ozone change projected for
the year 2075 based on a parameterized representation of a
one-dimensional model could vary from as high as over 50 percent
depletion, for a case where global use of chlorine and bromine
bearing substances grows at an average annual rate of 2.8 percent
from 1985 to 2100 (5.0 percent per year from 1985 to 2050, followed
by no growth through 2100)., to increased abundance of ozone of
approximately 3 percent, for a case where global use of chlorine and
bromine bearing substances declines to 20 percent of its 1985 value
by 2010. Exhibit ES-6 displays the global ozone change estimates
for these two scenarios, as well as estimates for four scenarios in
between; the six "what if scenarios examined include:
o 80% Reduction: Use of chlorine and bromine bearing substances
declines to 20 percent of its 1985 value by 2010, and remains
constant thereafter, yielding approximately 3.0 percent increased
ozone abundance by 2075;
o No Growth: no growth in use of chlorine and bromine-bearing
substances from 1985 to 2100, yielding approximately 0.3 percent
increased ozone abundance by 2075;
o 1.2% Growth: 1.2 percent growth from 1985 to 2050, followed by
no growth, yielding approximately 4.5 percent depletion by 2075;
o 2.5% Growth: 2.5 percent growth from 1985 to 2050, followed by
no growth, yielding approximately 25 percent depletion by 2075;
o 3.8% Growth: 3.8 percent growth from 1985 to 2050, followed by
no growth, yielding over 50 percent depletion by 2075;
o 5.0% Growth: 5.0 percent growth from 1985 to 2050, followed by
no growth, yielding over 50 percent depletion by 2075.
The trace gas concentration assumptions used in these six cases are:
C02 -- NAS 50th percentile; CH4 -- 0.017 ppm per year (approximately
1 percent of current CH4 concentration); and N20 -- 0.20 percent per
year.
72b. Current data are not sufficient for distinguishing whether CH4
concentrations are likely to increase in a linear manner (e.g, at
0.017 ppm per year, or approximately 1 percent of current
concentrations) or in a compound manner (e.g., at 1 percent per year,
compounded annually). The sensitivity of the ozone change estimates
in 2075 was evaluated for the following six assumptions regarding
future CH4 concentrations:
o Scenario A: compound annual growth of 1 percent from 1985 to
2010, followed by constant concentrations at 2.23 ppm; and
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ES-56
EXHIBIT ES-6
ESTIMATES OF GLOBAL OZONE DEPLETION IN 2075
FOR SIX CASES OF CFG USE
10
-10
Global
Ozone Change
•20
•30
-40
-SO
SOX No
I- Reduction Growth 1.2% 2.5% 3.8% 5.0%
3.2 0.3
greater than 50% depletion
Using a parameterized representation of a one-dimensional model, the
potential change in ozone was evaluated for six scenarios: 80% Reduction:
global CFC use declines to 20 percent of current levels by 2010, and remains
constant thereafter; No Growch: no growth in CFC use from current levels; 1.2%
Growth: 1.2 percent growth from 1985 to 2050, followed by no growth; 2.5%
Growth: 2.5 percent growth from 1985 to 2050, followed by no growth; 3.8%
Growth 3.8 percent growth from 1985 to 2050, followed by no growth; 5.0% Growth:
5.0 percent growth from 1985 to 2050, followed by no growth through 2100). The
trace gas concentration assumptions used in these six cases are: C02: NAS 50th
percentile; CH4: 0.017 ppm per year (approximately 1 percent of current CH4
concentration); and N20: 0.20 percent per year.
Assumptions:
Current 1-D models accurately reflect global depletion; Antarctic ozone
hole has no impact on global ozone levels.
Greenhouse gases that counter depletion grow at historically-extrapolated
rates.
Growth rates for ozone depletion are for global emissions; it is assumed
that emissions do not increase after 2050.
Ozone depletion limited to 50 percent.
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ES-57
o Scenario B: linear growth at 0.01275 ppm per year (75 percent of
the 0.017 ppm growth);
o Scenario C: linear growth of 0.017 ppm per year (approximately 1
percent of current concentrations);
o Scenario D: linear growth at 0.02125 ppm per year (125 percent
of the 0.017 ppm growth);
o Scenario E: compound annual growth of 1 percent;
o Scenario F: compound annual growth of 1 percent from 1985 to
2020, growing to 1.5 percent compound annual growth by 2050 and
thereafter.
For the 2.5% Growth scenario, the estimate of ozone depletion by 2075
ranges from about 14 percent (Scenario F) to 30 percent (Scenario A)
across these six CH4 assumptions evaluated. Exhibit ES-7 displays
the results for these six CH4 assumptions. As shown in the exhibit,
the difference between the 1 percent linear (0.017 ppm per year) and
1 percent compounded assumptions (Scenarios C and E) is approximately
6 percent depletion. This sensitivity of the ozone depletion
estimates to the assumption about linear versus compound growth of
CT'v concentrations is much larger than the sensitivity to the range
of assumptions examined regarding future C02 concentrations (from the
25th to the 75th percentile NAS estimates) and regarding future N20
concentrations (from 0.15 percent annual compound growth to 0.25
percent annual compound growth).
73. TWO-DIMENSIONAL C2-D) MODELS PREDICT GREATER AVERAGE GLOBAL DEPLETION THAN
ONE-DIMENSIONAL fl-D) MODELS. 2-D MODELS ALSO PREDICT THAT OZONE DEPLETION
WILL EXCEED THE GLOBAL AVERAGE AT HIGH LATITUDES AND BE LESS THAN THE
GLOBAL AVERAGE AT THE EQUATOR (chapter 18).
73a. For a case of 3 percent annual growth in emissions of CFCs, no
emissions of Halons, and increases in trace gases of: C02 --
approximately 0.6 percent per year; CH4 -- 1 percent per year; and
N20 -- 0.25 percent per year, a 2-D model estimates approximately 5.4
percent global average depletion by 2030. For the same scenario of
emissions and trace gas concentrations, the parameterized
representation of a 1-D model estimates only 3.0 percent depletion by
2030.
73b. For this same case of emissions and trace gas concentrations, the 2-D
model estimates of ozone depletion in 2030 at high latitudes are
approximately: 60°N -- 8.7 percent; and 50°N -- 7.0 percent.
74. ESTIMATES OF ATMOSPHERIC MODIFICATION. SKIN CANCER CASES AND DEATHS.
CATARACT CASES. MATERIALS DAMAGE. GLOBAL TEMPERATURE. AND SEA LEVEL DEPEND
ON THE RATE AT WHICH OZONE-DEPLETING GASES GROW. ATMOSPHERIC RESPONSE. DOSE
RESPONSE. AND WHETHER GREENHOUSE GASES THAT COUNTER OZONE DEPLETION GROW
INDEFINITELY. THE ASSUMPTIONS BEHIND QUANTITATIVE PROJECTIONS MUST BE
NOTED CAREFULLY (chapter 18).
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EXHIBIT ES-7
ESTIMATES OF GLOBAL OZONE DEPLETION IN 2075
FOR SIX METHANE CONCENTRATION ASSUMPTIONS
10
Global
Ozone Change
•10
•20
•30
-40
Scenario A Scenario B Scenario C Scenario 0 Scenario E Scenario F
•29.6
Using a parameterized representation of a one-dimensional model, the
potential change in ozone was evaluated for six assumptions about future methane
concentration: Scenario A: compound annual growth of 1 percent from 1985 to
2010, followed by constant concentrations at 2.23 ppm; Scenario B: linear growth
at 0.01275 ppm per year (75 percent of the 0.017 ppm growth); Scenario C: linear
growth of 0.017 ppm per year (approximately 1 percent of current
concentrations); Scenario D: linear growth at 0.02125 ppm per year (125 percent
of the 0.017 ppm growth); Scenario E: compound annual growth of 1 percent; and
Scenario F: compound annual growth of 1 percent from 1985 to 2020, growing to
1.5 percent compound annual growth by 2050 and thereafter.
All estimates based on the 2.5% Growth scenario 1985 to 2100 (2.5 percent
growth from 1985 to 2050, followed by no growth thereafter). The other trace
gas assumptions used in these cases are: C02: NAS 50th percentile; and N20: 0.20
percent growth per year.
Assumptions:
Current 1-D models accurately reflect global depletion; Antarctic ozone
hole has no impact on global ozone levels.
Greenhouse gases that counter depletion grow at historically-extrapolated
rates.
Growth rates for ozone depletion are for global emissions; it is assumed
that emissions do not increase after 2050.
Ozone depletion limited to 50 percent.
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ES-59
74a. The models used in this risk assessment assume that Antarctic ozone
depletion has no global implications and that global trends do not
invalidate estimates of current models.
74b. Except as noted, projected, effects assume that: greenhouse gases.grow
at historical rates indefinitely; current one-dimensional models
accurately project depletion; production of ozone depleters does not
grow after 2050; ozone depletion is limited to 50 percent; the action
spectrum causing skin cancers is DNA; and the temperature sensitivity
of the earth to doubled C02 is 3°C.
74c. In 2100, projections of ozone depletion range from over 50 percent
for the 5% Growth scenario (ozone depletion is constrained at 50
percent in this analysis) to 47 percent for the 2.5% Growth scenario
to an increase in column ozone abundance of nearly 5 percent for the
80% Reduction scenario.
74d. For cohorts born before 2075, the number of additional nonmelanoma
skin cancers projected ranges from a 261.5 million increase for the
5% Growth scenario to a 115 million increase for the 2.5% Growth
scenario to a reduction of 6.5 million skin cancers for the scenario
of 80% Reduction in all ozone depleters.
74e. For cohorts born before 2075, the increase in total melanoma cases
ranges from a 1.3 million case increase for the 5% Growth scenario to
a 609,000 increase for the 2.5% Growth scenario to 54,000 fewer cases
for the scenario of an 80% Reduction in all ozone depleters.
74f. For cohorts born before 2075, total mortality from melanoma and
nonmelanoma ranges from a 5.6 million increase for the 5% Growth
scenario to a 2.4 million increase for the 2.5% Growth scenario to
115,000 fewer cases for the scenario of 80% Reduction in all ozone
depleters.
74g. For cohorts born before 2075, the increase in total cataract cases
ranges from 26 million for the 5% Growth scenario to 15.1 million for
the-2.5% Growth scenario to 9,500 for the scenario of 80% Reduction
in ozone depleters.
74h. The rise in global temperature by 2075 ranges from 11.6°C in the 5%
Growth scenario to 5.6°C in the 2.5% Growth scenario to 4°C in the .
scenario of 80% Reduction in all ozone depleters.
74i. Impacts are also projected for other areas such as sea level rise,
ground-based ozone, materials, aquatics, and soybean yield.
75. QUANTITATIVE ESTIMATES OF RISKS VARY WITH ASSUMPTIONS ABOUT FUTURE
EMISSIONS OF GREENHOUSE GASES THAT WILL CONTRIBUTE TO GLOBAL WARMING
(chapter 18).
75a. Model projections that extrapolate historical growth rates of
greenhouse gases, which tend to counter ozone depletion, into the
indefinite future assume certain policy decisions from future
decisionmakers; alternative assumptions are possible.
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ES-60
75b. If future decisionmakers limit the concentrations of C02, N20, and
CH4 to prevent global warming from exceeding 2°C (±50%) in 2075, they
would by necessity have to limit growth of ozone depleters to the No
Growth case; for other cases increases in ozone depleters would be
too large to achieve that objective.
75c. Ozone depletion associated with the No Growth or 1.2% Growth
scenarios increases nearly 3 to 5 percent if global warming is
limited to 3°C (±50%); skin cancer deaths would increase 43 percent
for people alive today.
75d. Estimates of methane emissions are inherently uncertain even without
consideration of future policy decisions and could affect
quantitative risk estimates.
76. QUANTITATIVE ESTIMATES OF RISK VARY WITH UNCERTAINTY ABOUT DOSE-RESPONSE
COEFFICIENTS. ACTION SPECTRUM. LIMITS OF OZONE DEPLETION. AND
RESPONSIVENESS OF MODELS TO ATMOSPHERIC DEPLETION (chapter 18).
76a. For people alive today and born before 2075, additional skin cancer
cases would be reduced 45 percent if one assumes the lower dose-
response coefficients that are one standard error below the best
estimate and 66 percent higher if one assumes the higher coefficients
that are one standard error above the best estimate.
76b. For people alive today and born before 2075, additional skin cancer
cases would be reduced 11 percent if the Erythema action spectrum,
rather than the DNA action spectrum, were used to measure health
effects.
76c. Limiting projected depletion to 50 percent from what the
parameterized 1-D model would project reduces projected deaths for
later cohorts. For people born from 2030 to 2074, limiting depletion
to 50 percent reduces deaths by 13 percent for the 2.5% Growth
scenario and 66 percent for the 5% Growth scenario.
76d. For people alive today and born before 2075, skin cancer cases would
be reduced 62 percent in the 2.5%.Growth scenario if the atmosphere
were less sensitive to potential ozone depleters (using the 10th
percentile), and increased 54 percent if the atmosphere were more
sensitive (using the 90th percentile).
77. WHILE NATIONAL QUANTITATIVE ESTIMATES OF AQUATIC. CROP. GROUND-BASED OZONE.
AND SEA LEVEL RISE DAMAGE CANNOT BE MADE AT THIS TIME. CASE STUDY RESULTS
INDICATE THAT SIGNIFICANT INCREASES IN GROUND-BASED OZONE. LOSS OF AQUATIC
LIFE. SEA LEVEL RISE DAMAGE. AND LOSS OF CROP YIELD ARE POSSIBLE (chapter
18).
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ES-61
MAJOR PRIOR ASSESSMENTS OF THIS ISSUE
A number of prior assessments of stratospheric modification and climate
change have been done. A partial list with descriptions is included below:
STRATOSPHERIC OZONE
1. National Academy of Sciences (HAS),'1975, 1976, 1979, 1982, 1983
Several assessments of anthropogenic influences on the stratospheric ozone
layer were coordinated by the National Academy of Sciences. The first report,
in 1975, focused on the effects of proposed fleets of supersonic transports on
the stratosphere. Subsequent reports focused on chlorofluorocarbons.
2. National Aeronautics and Space Administration (NASA), 1977, 1986
NASA has convened several technical panels to review models and chemistry.
In addition, it completed a scientific assessment in 1986.
3. World Meteorological Organization,
National Aeronautics and Space Administration,
Federal Aviation Administration,
National Oceanic and Atmospheric Administration,
United Nations Environment Programme,
Commission of the European Communities, and
Bundeministerium fur Forschung und Technologic
International assessments of the stratosphere have been conducted by the
European Community, the United Kingdom's Department of the Environment (1979),
and by the United Nations Environment Coordinating Committee on the Ozone Layer
(1981, 1984, 1986).
The most recent and most ambitious assessment of the scientific issues
regarding the stratosphere was coordinated by the World Meteorological
Organization with the assistance of several other organizations. Approximately
150 of the world's leading scientists participated in this assessment.
CLIMATE
1. Climatic Impact Assessment Program, 1974
Initial concern over anthropogenic influences on the climate and the
stratospheric ozone layer led in 1971 to the establishment of the Climatic
Impact Assessment Program (CIAP). Coordinated by the Department of
Transportation, CIAP's objective was to assess, by a report in 1974, the impacts
of climatic changes due to projected fleets of supersonic transports.
%
2. National Academy of Sciences: 1979, 1982, 1983
Three panels were convened by the National Academy of Sciences to assess the
scientific basis and certainty of the effects of carbon dioxide concentrations
on global climate. Reports were released in 1979, 1982, and 1983.
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3. World Meterological Organization,
International Council of Scientific Unions, and
United Nations Environment Programme
Efforts to achieve an international scientific consensus on carbon dioxide,
trace gases, and climate were coordinated by the World Meterological
Organization (WHO), International Council of Scientific Unions (ICSU), and
United Nations Environment Programme (UNEP). Assessments were released in 1979,
1981,. and 1985.
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REFERENCES
Commission of the European Communities, (1981), Evaluation of the Effects of
Chlorofluorocarbons on Atmospheric Ozone: Present Status of Research. EEC
Brussels, Belgium.
Department of the Environment, (1979), Chlorofluorocarbons and the Effect on
Stratospheric Ozone. Pollution Paper No. 15, Central Directorate of
Environmental Pollution, Department of the Environment, London, U.K.
EPA Science Advisory Board, (March 1987), Review of EPA's An Assessment of the
Risks of Stratospheric Modification, prepared by EPA's Science Advisory
Board, Washington, D.C., SAB-EC-87-025.
Grobecker, A.J., S.C. Coroniti, and R.H. Cannon, Jr., (1974), Report of
Findines. The Effects of Stratospheric Pollution bv Aircraft.
DOT-TST-75-50, prepared by the Department of Transportation Climatic Impact
Assessment Program, Washington, DC.
Hoffman, J.S. (1986), "The Importance of Knowing Sooner," in J.G. Titus (ed.),
Effects of Changes in Stratospheric Ozone and Global Climate. Volume 1:
Overview. U.S. Environmental Protection Agency, Washington, DC.
Hunter, J.R., S.E. Kaupp, and J.M. Taylor, (1S'2), "Assessment of Effects of
Radiation on Marine Fish Larvae," in J. Collins (ed.), The Role of Solar
Ultraviolet Radiation in Marine Ecosystems, pp 459-497, Plenum, New York.
National Academy of Sciences (NAS), (1979), Carbon Dioxide and Climate: A.
Scientific Assessment. National Academy of Sciences, Washington, DC.
NAS (1982), Carbon Dioxide and Climate: A Second Assessment. National Academy
of Sciences, Washington, DC.
NAS (1983), Changing Climate. Report of the Carbon Dioxide Assessment
Committee. National Academy of Sciences, Washington, DC.
NAS (1975), Environmental Impact of Stratospheric Flight. NAS, Washington, DC.
NAS (1976), Halocarbons: Effects on Stratospheric Ozone. NAS, Washington, DC.
NAS (1979), Protection Against Depletion of Stratospheric Ozone by
Chlorofluorocarbons. NAS, Washington, DC.
NAS (1979), Stratospheric Ozone Depletion bv Halocarbons: Chemistry and
Transport. NAS, Washington, DC.
NAS (1982), Causes and Effects of Stratospheric Ozone Reduction: An Update.
NAS, Washington, DC.
NAS (1984), Causes and Effects of Changes in Stratospheric Ozone: Update 1983.
NAS, Washington, DC.
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National Aeronautics and Space Administration (NASA) (1977),
Chlorofluoromethanes and the Stratosphere. NASA Reference Publication 1010,
NASA, Washington, DC.
NASA (1986), Present State of Knowledge of the Upper Atmosphere: Ah Assessment
Report. Processes that Control Ozone and Other Climatically Important Trace
Gases. NASA Reference Publication 1162, NASA, Washington, DC.
Scotto, J. (1986), "Nonmelanoma Skin Cancer - UV-B Effects," in J.G. Titus
(ed.), Effects of Changes in Stratospheric Ozone and Global Climate. Volume
2: Stratospheric Ozone. U.S. Environmental Protection Agency, Washington,
DC.
Serafino, G. and J. Frederick (1986), "Global Modeling of the Ultraviolet Solar
Flux Incident on the Biosphere," prepared for the U.S. Environmental
Protection Agency.
United Nations Environment Programme, UNEP (1984), Environmental Assessment of
Ozone Layer Depletion and its Impact as of October 1984. Coordinating
Committee on the Ozone Layer (CCOL), UNEP.
UNEP (1986), draft report of the CCOL meeting, 1986.
World Meteorological Organization (1979), Report of the First Session of the CAS
Working Group on Atmospheric Carbon Dioxide. WMO Project on Research and
Monitoring of Atmospheric C02, Rep. No. 2, Commission for Atmospheric
Sciences, WMO, Geneva, Switzerland.
WMO (1981) , Joint WMO/ICSU/UNEP Meeting of Experts on the Assessment of the Role
of C02 on Climate Variations and their Impact. Joint Planning Staff, WMO,
Geneva, Switzerland.
WMO (1985),. Report of the International Conference on the Assessment of the Role
of Carbon Dioxide and of other Greenhouse Gases in Climate Variations and
Associated Impacts. WMO-No. 661, WMO/ICSU/UNEP, WMO, Geneva, Switzerland.
WMO (1986), Atmospheric Ozone 1985. Assessment of our Understanding of the
Processes Controlling its Present Distribution and Change. WMO Global Ozone
Research and Monitoring Project -- Report No. 16, WMO, Geneva, Switzerland.
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TABLE OF CONTENTS
PAGE
VOLUME I
ACKNOWLEDGMENTS 1
ORGANIZATION ES-1
INTRODUCTION ES - 2
SUMMARY FINDINGS ES-5
CHANGES IN ATMOSPHERIC COMPOSITION '. ES -15
POTENTIAL CHANGES IN OZONE AND CLIMATE ES - 23
HUMAN HEALTH, WELFARE, AND ENVIRONMENTAL EFFECTS ES-32
QUANTITATIVE ASSESSMENT OF RISKS WITH INTEGRATED MODEL ES-54
VOLUME II
ACKNOWLEDGEMENTS 8 i
INTRODUCTION 1
The Rise of Concern About Stratospheric Change 1
Concern About Public Health and Welfare Effects of Global
Atmospheric Change 1
Need for Assessments 2
1. GOALS AND APPROACH OF THIS RISK ASSESSMENT 1-1
Analytic Framework 1-1
Supporting Documents and Analysis for this Review 1-2
Chapter Outlines 1-2
2. STRATOSPHERIC PERTURBANTS: PAST CHANGES IN CONCENTRATIONS
AND FACTORS THAT DETERMINE CONCENTRATIONS 2-1
Summary 2-1
Findings 2-3
Measured Increases in Tropospheric Concentrations of
Potential Ozone Depleters 2-4
Measured Increases in Tropospheric Concentrations of
Potential Ozone Increasers 2-13
Factors that Influence Trace Gas Lifetimes 2-21
Long-Lived Trace Gases 2-22
Trace Gases with Shorter Lifetimes 2-26
Carbon Dioxide and the Carbon Cycle 2-26
Source Gases for Stratospheric Sulfate Aerosol (OCS, CS2) 2-26
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TABLE OF CONTENTS
(Continued)
PAGE
Appendix A: CFC Emissions-Concentrations Model 2-28
References 2-30
3. EMISSIONS OF INDUSTRIALLY PRODUCED POTENTIAL OZONE MODIFIERS 3-1
Summary 3-1
Findings 3-3
Introduction 3-6
Chlorofluorocarbons 3-6
Chlorocarbons 3-58
Halons 3-59
References 3-66
Appendix A: Chemical Use Estimate Made Available
Since Publication of the Risk Assessment A-l
Appendix A: References A-10
4. FUTURE EMISSIONS AND CONCENTRATIONS OF TRACE GASES WITH
PARTLY BIOGENIC SOURCES 4-1
Summary 4-1
Findings 4-2
The Influence of Trace Gases on the Stratosphere and
Troposphere 4-4
Trace Gas Scenarios 4-4
Effects of Possible Future Limits on Global Warming 4-23
Conclusion 4-23
References 4-25
5. ASSESSMENT OF THE RISK OF OZONE MODIFICATION 5-1
Summary 5-1
Findings .' 5-3
Introduction 5-6
Equilibrium Predictions for Two-Dimensional Models 5-18
Time Dependent Predictions for One-Dimensional
Models for Different Scenarios of Trace Gases 5-32
Time Dependent Predictions for Two-Dimensional Models
with Different Scenarios of Trace Gases 5-40
Models Fail to Represent All Processes That Govern
Stratospheric Change in a Complete and Accurate Manner 5-61
The Implications of Ozone Monitoring for Assessing Risks
of Ozone Modification 5-80
References 5-104
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ES-57
TABLE OF CONTENTS
(Continued)
PAGE
VOLDME III
6. CLIMATE 6-1
Summary 6-1
Findings 6-2
The Greenhouse Theory 6-7
Radiative Forcing by Increases in Greenhouse Gases 6-8
Ultimate Temperature Sensitivity 6-15
The Timing of Global Warming 6-18
Regional Changes in Climate Due to Global Warming 6-22
Effects on the Stratosphere of Possible Control of Greenhouse
Gases
6-26
Attachment A: Description of Model to be Used in Integrating
Chapter
6-28
Attachment B: Trace Gas Scenarios 6-32
References 6-33
7. NONMELANOMA SKIN TUMORS .' 7-1
Summary 7-1
Findings 7-2
Background on Solar Radiation and the Concept of Dose 7-5
Introduction 7-5
Biology of Nonmelanoma Skin Tumors: Links to UV-B 7-11
Epidemiological Evidence 7-27
Dose-Response Relationships '. 7-40
Attachment A 7-49
References 7-58
8. CUTANEOUS MALIGNANT MELANOMA 8-1
Summary 8-1
Findings 8-3
Introduction 8-7
Epidemiologic Evidence 8-11
Experimental Evidence .. 8-28
Dose-Response Relationships 8-29
References 8-41
9. UVR-INDUCED IMMUNOSUPPRESSION: CHARACTERISTICS AND POTENTIAL
IMPACTS 9-1
Summary 9-1
Findings 9-3
Introduction 9-5
Basic Concepts in Immunology 9-5
Salt: Skin-Associated Lymphoid Tissues 9-7
Effects of Ultraviolet Radiation on Immunological Reactions 9-8
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TABLE OF CONTENTS
(Continued)
PAGE
Human Studies 9-14
Effects of Ultraviolet Radiation on Infectious Diseases 9-15
References 9-18
10. CATARACTS AND OTHER EYE DISORDERS 10-1
Summary 10-1
Findings 10-2
Cataracts 10-3
Potential Changes in Senile Cataract Prevalence for
Changes in UV-B 10-29
Other Eye Disorders 10-33
References 10-37
11. RISKS TO CROPS AND TERRESTRIAL ECOSYSTEMS FROM ENHANCED
UV-B RADIATION , 11-1
Summary 11-1
Findings 11-2
Introduction 11-5
Issues and Uncertainties in Assessing the Effects
of UV-B Radiation on Plants 11-5
Issues Concerning .UV Dose and Current Action Spectra
for UV-B Impact Assessment 11-5
Issues Concerning Natural Plant Adaptations to UV Radiation 11-7
Issues Associated with the Extrapolation of Data from
Controlled Environments to the Field 11-10
Uncertainties in Our Current Knowledge of UV-B Effects on
Terrestrial Ecosystems and Plant Growth Forms 11-11
Uncertainties with the Ability to Extrapolate Knowledge to Higher
Ambient C02 Environment and Other Atmospheric Pollutants 11-13
Risks to Crop Yield Resulting from an Increase rn
Solar UV-B Radiation 11-15
Risks to Yield Due to a Decrease in Quality 11-20
Risks to Yield Due to Possible Increases in
Disease or Pest Attack 11-20
Risks to Yield Due to Competition with Other Plants 11-22
Risks to Yield Due to Changes in Pollination and Flowering 11-23
References 11-25
12. AN ASSESSMENT OF THE EFFECTS OF ULTRAVIOLET-B
RADIATION ON AQUATIC ORGANISMS 12-1
Summary 12-1
Findings 12-2
Introduction 12-4
Background on Marine Organisms and Solar Ultraviolet
Radiation 12-4
Effects of UV-B Radiation in Phytoplankton 12-9
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TABLE OF CONTENTS
(Continued)
PAGE
Effects on Invertebrate Zooplankton 12-11
Effects on Ichthyoplankton (Fisheries) 12-23
Conclusions 12-28
References 12-29
13. EFFECTS OF UV-B ON POLYMERS .'. 13-1
Summary 13-1
Findings 13-2
Photodegradation of Polymers 13-4
Polymers in Outdoor Uses and the Potential for Degradation 13-7
Damage Functions and Response to Damage 13-16
Effect of Temperature and Humidity on Photodegradation 13-29
Future Research 13-31
References 13-32
14. POTENTIAL EFFECTS OF STRATOSPHERIC OZONE DEPLETION ON
TROPOSPHERIC OZONE 14-1
Summary 14-1
Findings 14-2
Introduction 14-3
Potential Effects of Ultraviolet Radiation and Increased
Temperatures on Ground-based Ozone 14-5
Conclusions and Future Research Directions 14-9
References 14-14
15. CAUSES AND EFFECTS OF SEA LEVEL RISE 15-1
Summary 15-1
Findings 15-2
Causes of Sea Level Rise : 15-5
Effects of Sea Level Rise : 15-15
Conclusion 15-32
Notes 15-33
References 15-34
16. POTENTIAL EFFECTS OF FUTURE CLIMATE CHANGES ON FORESTS
AND VEGETATION, AGRICULTURE, WATER RESOURCES
AND HUMAN HEALTH 16-1
Summary 16-1
Findings 16-5
References 16-10
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TABLE OF CONTENTS
(Continued)
PAGE
17. MODELS FOR INTEGRATING THE ANALYSES OF HEALTH AND
ENVIRONMENTAL RISKS ASSOCIATED WITH OZONE MODIFICATION 17-1
Summary 17-1
Introduction 17-2
The Model as a Framework •;._ 17-2
Analysis Procedure 17-4
Model Limitations 17-9
References 17-11
Appendix A: Model Design and Model Flow A-l
Appendix B: Scenarios of Chemical Production, Population,
and GNP B-1
Appendix C: Evaluation of Policy Alternatives C-l
Appendix D: Emissions of Potential Ozone-Depleting Compounds D-l
Appendix E: Atmospheric Science Module E-l
Appendix F: Health and Environmental Impacts of Ozone
Depletion F-1
18. HUMAN. HELATH AND ENVIRONMENTAL EFFECTS 18-1
Summary 18-1
Findings 18-2
Introduction 18-6
Methods for Estimating Health and Environmental Risks 18-11
Description of Range of Production, Emissions, and Concentrations
Scenarios for Evaluating Risks 18-12
Sensitivity of Health and Environmental Effects to Differences
in Emissions of Ozone Depleters 18-18
Sensitivity of Results to Alternative Atmospheric Assumptions 18-23
Sensitivity of Effects to Uncertainty in Dose Response 18-54
Relative Importance of Key Uncertainties 18-61
Summary 18-62
References '. , 18-65
VOLUME IV
Appendix A
Ultraviolet Radiation and Melanoma
VOLUME V
Appendix B
Potential Effects of Future Climate Changes on Forests and
Vegetation, Agriculture, Water Resources, and Human Health
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ES-71
TABLE OF CONTENTS
(Continued)
VOLUME VI
Technical Support Documents
Appendix C
Projecting Production of Ozone Depleting Substances
VOLUME VII
Technical Support Documents
Appendix D
Scientific Papers
VOLUME VIII
Technical Support Documents
Appendix E .
Current Risks and Uncertainties of Stratospheric Ozone Depletion
Upon Plants
-------
APPENDIX C
FRAMEWORK AND METHOD FOR ESTIMATING
COSTS OF REDUCING THE USE OF OZONE-DEPLETING
COMPOUNDS IN THE U.S.
NOTE: This Appendix is a copy of an appendix originally prepared for
U.S. EPA's Regulatory Impact Analysis: Protection of
Stratospheric Ozone (1987) (EPA's Regulatory Impact Analysis). In
the RIA document, this appendix was included as Appendix I.
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APPENDIX I
FRAMEWORK AND METHOD FOR
ESTIMATING COSTS OF REDUCING THE USE OF
OZONE-DEPLETING COMPOUNDS IN THE U.S.
This paper describes the analytical framework and methods used to estimate
the costs of reducing the use of potential ozone-depleting compounds. The
emphasis of the approach is on estimating the net social costs of reducing the
use of the compounds. An essential step in estimating these social costs is
assessing potential industry responses to regulations which would be implemented
to achieve the desired reductions. This assessment, in turn, calls for estimates
of the private costs faced by the affected industries of complying with the
regulations. These private compliance costs are also required for performing a
Regulatory Flexibility Act analysis. Hence, the approach employed provides
estimates of both private and social costs.
The framework for estimating social costs essentially consis-ts of measuring
the changes in consumer surplus caused by the regulations in the markets for
chlorofluorocarbon (CFG) and Haloh compounds (hereafter referred together as
CFCs) . Hence, a major component o'f the analysis is characterizing these CFC
markets and, in particular, estimating the derived demand schedules for each.
The appendix is organized as follows:
o Section 1 presents the economic framework for estimating
costs. It discusses the assumptions employed in the
analysis and the economic justification for measuring
changes in consumer surplus in the CFC markets.
o Section 2 discusses the analysis of the four basic
regulatory alternatives -- auctioned permits,
allocated quotas, regulatory fees, and engineering
controls and product bans.
o Section 3 describes the methods used to estimate derived
demand schedules for CFCs using the engineering and
financial data collected by EPA. It also describes the
procedure for estimating changes in consumer surplus using
the estimated derived demand schedules.
o Section 4 discusses some of the inherent limitations of
the analytic methods used.
1 The methods and results of the Regulatory Flexibility Act analysis are
presented separately in Appendix L.
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1-2
1. CONCEPTUAL APPROACH FOR ESTIMATING REGULATORY COSTS
This section discusses the economic theory that underlies the approach used
to estimate the private and social costs of regulations that restrict the use of
CFCs. The basic method for estimating costs is to measure changes in producer
and consumer surplus in the relevant markets that result from restrictions on
CFC use required by regulation.
The section initially identifies the relevant markets, establishes the
relationships between these markets, and characterizes the supply and demand
schedules that underlie them. The section then turns to the issue of measuring
changes in producer -and consumer surplus in these markets due to exogenously
imposed restrictions on CFCs. The section ends with a discussion of the
differences between private and social costs.
1.1 Affected Parties and Relevant Markets
To analyze the costs of the proposed regulations it is necessary, first, to
identify the parties that are likely to be significantly affected by the
regulations and the markets in which the changes in the welfare of these parties
can be measured.
The parties likely to be affected by the regulations are.
o firms producing CFCs;
o owners of factors employed in the production of CFCs;
o firms in the CFC-using industries;
o owners of factors employed in the CFC-using industries;
and
o final consumers of goods manufactured using CFCs.
To determine the costs borne by each of these parties it is generally
necessary to measure changes in consumer and producer surpluses in two sets of
markets:
o the markets for the various CFC compounds, i.e., the
markets in which CFCs are sold by producers of these
compounds to the various CFC-using industries; and
o the markets for the outputs of the CFC-using industries,
i.e., the markets in which the products of the CFC-using
industries are sold to consumers.
2 It is assumed that the markets for complements and substitutes for the
outputs of CFC-using industries would not experience price changes as che result
of reductions in CFC use. Therefore, these markets do not experience gains or
losses.
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1-3
It is possible, however, to measure the net costs of the proposed regulations by
measuring changes in surpluses in the CFC markets alone. Here net costs are
defined to be the sum of the costs borne by the affected parties minus any
transfers (e.g., to the government) in the form of revenues generated by the
regulations (e.g., fees collected). The rationale for measuring these costs
entirely in the CFC markets is explained in the following sections.
1.2 General Analysis of the Relationships Between the Relevant Markets
A general overview of the relationships between the markets for CFCs and the
markets for the outputs of the CFC-using industries is presented in this
section. The overview is a stylized one in that it employs very general
assumptions about the shapes of the various supply and demand curves. This
allows a derivation of the full range of relationships that may exist between
the relevant markets.
An important assumption maintained throughout the analysis is that all
relevant markets are competitive. Furthermore, it is assumed that the various
"application categories" discussed in Section 3 of this appendix roughly
correspond to distinct industries. Hence, the term application category and
industry are used synonymously in this appendix.
Note, finally, that the discussion in this and subsequent sections is
couched frequently in terms of a single ozone-depleting compound (e.g., CFC-11).
Thus, reference is made to a single market. Howeve^, the analysis applies to
the markets for all of the CFC and Halon compounds subject to the proposed
regulations.
Before examining the relationships between the relevant markets, the supply
and demand schedules underlying these markets are briefly characterized.
1.2.1 DEMAND SCHEDULES
Three sets of relevant demand schedules can be identified:
o the derived demand for CFCs of a single CFC-using
industry;
o the demands for the outputs of the CFC-using industries;
and
o the aggregate derived demand for CFCs of all CFC-using
industries.
The relationship among these demands is best explained by means of an example.
An important use of CFCs is in manufacturing air-conditioners. This industry
has a derived demand schedule for CFCs that specifies the quantity of CFCs it
^ The assumption of competitiveness is probably reasonable for the
CFC-using industries. However, the CFC-producing industry is highly
concentrated, potentially leading to a non-competitive situation. The
implications of a non-competitive CFC-producing industry are described below.
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1-4
would buy at various CFC prices. This industry derived demand schedule is
obtained by horizontally summing the derived demand schedules of the firms in
the air-conditioner industry.^ The shape of this derived demand schedule for
this industry is influenced, in part, by the demand for air-conditioners (i.e.,
by the demand for the outputs of the CFC-using industry).
The aggregate derived demand schedule for CFCs is obtained by horizontally
summing the derived demand schedules of all the CFC-using industries
(air-conditioning, foam blowing, etc.). Thus, the aggregate derived demand
schedule for CFCs is obtained via a two-stage procedure:
o First, the derived demand schedules of firms in a given
industry are summed to obtain the derived demand schedule
for CFC of that industry. This is carried out for each
CFC-using industry.
o Then, the derived demand schedules for CFC of all
CFC-using industries are summed to obtain the aggregate
derived demand schedule for CFC.
Typically, derived demand schedules for an input to production assume that
factors influencing the demand for the input other than its price are held
constant. Most important among these factors are the prices of other inputs and
the price of the output produced using the input in question. The relationship
between other input prices and the demand for CFC inputs depends on whether
other inputs complement or substitute for the use of CFCs in the production
process.
The relationship between output price and CFC input demand hinges on the
link between output price and output quantity. The price a competitive firm
receives for its output determines the level of output that it produces. The
higher the price the firm receives; the larger is the quantity of output it
produces (provided that marginal production costs are increasing, as is commonly
assumed). This output level, in turn, determines the quantity of input that is
needed by the firm. Higher output levels imply higher demands for the input.
Thus, there is a positive relationship between output price and input demand.
Although derived demand schedules are commonly specified with output price
held constant, this need not be the case. Derived demand schedules can also be
specified holding output quantity constant, requiring only the removal of the
intermediate link between output price and output quantity. In later sections,
derived demand schedules are specified in this manner. However, in this section
we adhere to economic convention and assume output price is held constant.
It is assumed throughout that external effects of scale are negligible so
that industry demand and supply curves can be approximated by horizontally
summing individual firm demand and supply curves. An example of an external
effect of scale is factor prices rising as industry output expands.
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1-5
1.2.2 SUPPLY SCHEDULES
Two sets of relevant supply schedules can be identified:
o the supply schedule for CFCs of-the CFC-producing
industry; and
o the output or product supply schedules of the CFC-using
industries.
The supply schedule for CFCs gives the- total amount of CFCs that would be
supplied by CFC producers for various prices of CFCs. This supply schedule is
obtained by horizontally summing the supply schedules of the individual
CFC-producing firms.
Turning to the CFC-using industries, each industry has an output supply
schedule that specifies the level of output it supplies for different output
prices. The output supply schedule for each industry is obtained by
horizontally summing the supply curves of the firms in the industry. These
firm-level supply schedules are based on firms' marginal costs of production.
Thus, along a supply schedule, the prices of inputs are held constant. The
effect of a change in the price of'an input, such as CFCs, is to shift the
output supply schedules because of its effect on the marginal cost of
production.
1.2.3 RELATIONSHIPS BETWEEN THE CFC (INPUT) MARKET AND THE OUTPUT MARKET
Exhibit 1-1 shows an illustrative supply schedule and an illustrative
aggregate derived demand schedule for a CFC. Along the aggregate derived demand
schedule, the prices of the outputs of the various CFC-using industries are held
constant at their current equilibrium values. The equilibrium price and
quantity of the CFC are determined by the intersection of the supply schedule
and the aggregate derived demand schedule. The equilibrium price p is the
price of the CFC faced by all the firms in CFC-using industries. The
equilibrium quantity q is the total quantity of the CFC demanded by the
CFC-using industries at this price.
Exhibit 1-2 shows the output supply curve of one of the many CFC-using
industries as well as the demand schedule it faces for its output. Along the
output supply curve, the price of the CFC is held constant at its current
equilibrium value, p . The equilibrium price and quantity in the output
market, P and Q , are given by the intersection of the supply and demand
schedules.
It is assumed that supplies of all inputs (other than CFCs) are perfectly
elastic.
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1-6
EXHIBIT 1-1
MARKET FOR A CFC
Price of
CFC in
Year t
Supply of CFC
Aggregate
Derived
Demand for
CFC
Quantity of
CFC in Year t
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1-7
EXHIBIT 1-2
MARKET FOR THE OUTPUT OF A CFC-USING INDUSTRY
Price of
Output
in Year t
Supply of Output
Demand for
Output
Quantity of
Output in Year t
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1-8
The relationships between the CFC market and the output markets can be
identified by tracing the effects of an increase in CFC price due to an upward
shift in the supply schedule for CFC. The initial effect of the higher CFC
price is to shift up the output supply schedules of the CFC-using industries.
This shift would eventually result in a higher equilibrium output price and a
lower equilibrium quantity in each output market.
Given the dependence of the derived demand schedule for CFCs on the level of
output produced, the lower equilibrium output quantities would cause a
contraction in the aggregate derived demand for CFCs. This contraction would
lower the equilibrium price of CFCs, assuming the supply curve for the CFCs is
upward sloping, and initiate a new round of shifts in the two markets.
The above interaction between the input and output markets would continue
until a new equilibrium is established in both markets. This new equilibrium is
illustrated in Exhibit 1-3. Panel (a) shows the input market and panel (b)
shows one of-the many output markets. The equilibrium CFC price in.panel (a)
rises from p to p and the equilibrium quantity falls from q to q . In
t t Q ^ t • t
panel (b), the equilibrium output price rises from P to P and the equilibrium
01 t t
output quantity falls from Q to Q . Along the new output supply schedule,
1
labeled S-, the price of the CFC is held constant at its new equilibrium level
1 •"•
V
To summarize, the key relationships between the market for a CFC and the
markets for outputs are: (1) th^ dependence of the derived demand for the CFC on
the demand for the outputs of the CFC-using industry; and (2) the relationship
between the equilibrium price of the CFC, which is determined in the input
(i.e., CFC) market, and the positions of the output (i.e., CFC-using industry)
supply'curves. In the general setting examined, an upward shift in the CFC
supply curve triggers a series of linked adjustments in each of the markets
before a new equilibrium is achieved.
1.3 Assumptions Regarding CFC Supply and CFC-Using Product Demands
The discussion contained in the previous section is based on very general
assumptions about the characteristics of the various supply and demand
schedules. This section presents the specific assumptions we make about the
supply curve for CFCs and the output demand curves faced by the CFC-using
industries, and the justification for these assumptions.
Given the assumption that all relevant markets are competitive, the supply
schedule for CFCs reflects the marginal costs of producing CFCs. A survey of
the available literature on the CFC industry revealed no engineering data on
marginal production costs. Moreover, data suitable for econometric estimation
of CFC supply schedules are also not available. Therefore, empirical derivation
of CFC supply curves is not possible.
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1-9
EXHIBIT 1-3
EFFECTS OF A SHIFT IN THE CFC SUPPLY CURVE: GENERAL CASE
Price of
CFC in
Year t
(a) Market for CFC
*',
Quantity of CFC
in Year t
Price of
Output
in Year t
(b) Market for Output of
a CFC-Using Industry
1 O° Quantity of Output
» v » in Year t
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1-10
An examination of the CFG production process, and those of similar
chemicals, suggests, however, that the marginal costs of production are likely
to be constant over a very large range of output. This implies that the supply
schedule for CFCs is perfectly elastic (i.e., horizontal) over a large range of
output. For purposes of this analysis, it is assumed that the supply curve is
perfectly elastic over its entire range.
Because the CFC-producing industry is highly concentrated in the U.S., it
may not exhibit all the necessary characteristics of a competitive market. In
such cases, price may exceed marginal costs. Due to the lack of empirical data,
the extent to which the price of CFCs 'exceeds the marginal cost of production
has not been assessed.
A review of the available data on production costs for the CFC-using
industries indicates that CFC costs account for only a small fraction (under 5
percent) of total production costs for a majority of the outputs examined. This
implies that even substantial increases in the price of CFCs would cause only
small increases in the marginal costs of production in the CFC-using industries.
Hence, the shifts in the output supply curves for these industries caused by
higher CFC prices will be small. This, in turn, implies that higher CFC prices
will induce only small changes in equilibrium prices and quantities in the
output market if demand is not very elastic.
Therefore, for outputs that have low CFC cost shares and low demand
elasticities, a simplifying assumption is made that, over the relevant range,
demand for outputs is perfectly inelastic. That is, the demand schedules for
these outputs are assumed to be vertical so that changes in output price have no
effect on the quantity of output demanded. This approximation is acceptable
given the small changes in output price and output quantity associated with
higher CFC prices. In terms of the final social cost estimates derived, the
approximation generates a small upward bias in the estimates.
For the few outputs that have relatively large CFC cost shares and possibly
higher demand elasticities, the potential for output substitution is
accommodated by interpreting the demand for output in terms of the services
provided by the CFC-based output. This services-provided demand is then assumed
to be perfectly inelastic.
For example, CFC costs account for roughly 16 percent of the total costs of
making rigid polyurethane foam, a material used as insulation in building
construction. The services provided by this foam consist of insulation
(measured as an R-value) over the expected life of the foam. Because substitute
insulation materials are available at reasonable prices, it would be
inappropriate to assume that the quantity of rigid foam demanded is constant
when there are large increases in the price of CFCs. Thus, in modeling the
demand for rigid polyurethane foam, the price of the foam is compared to the
cost of using substitute insulation materials. (The costs of using substitutes
include the costs of higher energy bills given their inferior insulation
properties). If the price of rigid polyurethane foam exceeds the cost of using
a substitute (including the increased energy costs), consumers are assumed to
switch to the substitute and to stop buying rigid polyurethane foam.
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1-11
1.4 Characteristics of Derived Denand Schedules for CFCs
The smooth derived demand schedules drawn in Exhibits 1-1 and 1-3 are
consistent with the assumption, traditional in economic theory, that production
processes are such that inputs can be continuously substituted for one another.
In other words, it is always possible to reduce use of an input and keep the
level of output constant by increasing the use of other inputs. This assumption
implies that increases in the price of an input invariably result in a lower
quantity demanded of that input (assuming other input prices are constant).
Engineering data on production processes indicate, however, that
substitution possibilities are limited for any given production technology."
In general, these data imply that, for a specific production technology, no
substitution of inputs is possible. In other words, it is not possible to
reduce use of one input and keep the quantity of output constant by raising the
use of other inputs. Production technologies of this type are called
fixed-proportions technologies. For these technologies, the quantity of input
used per unit of output is a constant.
The data collected on options for reducing CFC use in the various
application categories imply that .the portions of the overall production
processes related to CFC use are characterized by fixed proportions. Thus, for
a given production technology, the quantity of CFCs used per unit of output is a
constant. It follows that the quantity of CFCs demanded for a given level of
output is constant over some range of CFC price. This implies that the derived
demand schedule for CFCs of a single CFC-using firm or industry (along which
output is held constant) is a series of vertical line segments or a step
function. As shown in Exhibit I- i, the quantity of output (rather than the
price of output) is constant along each of these segments.
Although substitution of inputs is not possible within any given
fixed-proportions technology, it is possible across fixed-proportions
technologies. For instance, in the context of CFC use, the quantity of CFCs
used per unit of output is constant for a given fixed-proportions production
technology, but the quantity may be changed by "switching" to a different
fixed-proportions production technology. As used here, switching technologies
encompasses replacing CFCs with less ozone depleting chemicals, modifying
production processes, and recycling or recovering CFCs.
CFC-using firms will choose the production technology that minimizes
production costs given prevailing input prices. Changes in input price, if
sufficiently large, will induce firms to switch technologies and alter their
levels of input use for a given level of output.
For example, if the price of CFC rises sufficiently, CFC-using firms will
switch to less CFC-intensive production technologies (assuming these exist) and
See P.R.G. Layard and A.A. Walters, Microeconomic Theory, McGraw-Hill,
1978, Chapter 10 for a general discussion of this issue. For a good case study,
see J.M. Griffin, "The Process Control Alternative to Statistical Cost
Functions: An Application to Petroleum Refining," American Economic Review.
March 1972, Vol. 62, pp. 46-56.
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1-12
EXHIBIT 1-4
CHARACTERIZING THE DERIVED DEMAND SCHEDULE FOR CFCs
AS A STEP FUNCTION
Price of
CFC in
Year t
_ »
Pt
2
Pt
Pt
Pt
A
P?
_______
q
F
E _
D
'
C B
r A
2 _ l n 0 Quantity of
» q l q l CFC in Year t
-------
1-13
reduce their use of CFCs per unit of output. This is reflected in Exhibit
1-4 by a switch from line segment AB to the line segment labeled CD. For a CFC
1 2
price above p but below p , the switch to a less CFC-intensive production
t t ' • o i -
technology implies a reduction in the quantity of CFC demanded from q to q
t t
The derived demand schedule in Exhibit 1-4 further implies that if the CFC
2
price rises above p , firms switch to an even less CFC-intensive production
t "12
technology that reduces their CFC use from q to q . ^
t t
Thus, each vertical "step" in the derived demand schedule corresponds to a
different fixed-proportions production technology. As the price of CFCs
increases, firms "climb up" the demand schedule and switch to less CFC intensive
technologies. Along the entire demand schedule, the quantity of output produced
by the firm or CFC-using industry in question is constant, as are the prices of
other inputs.
Although there are three steps in Exhibit 1-4, the actual number of steps in
a derived demand schedule may be smaller or larger. The number of steps depends
on the number of suitable production technologies: more technologies imply more
steps in the schedule. Foi. derived demand schedules that are obtained by
horizontally summing demand schedules for different firms or different
industries, such as the aggregate derived demand schedule for CFC defined above,
the number of steps is likely ..o be large.
1.5 Relationships Between the Relevant Markets
Given the assumptions regarding the shapes of the relevant supply and demand
schedules, the relationships between the CFC market and the various output
markets are simpler than those described in Section 1.2. This can be
established by once again tracing the effects of an increase in CFC price due to
an upward shift in the supply curve for CFC.
Panel (a) of Exhibit 1-5 shows the CFC market with a perfectly elastic
supply schedule and a step aggregate derived demand schedule for CFC. Along
this demand schedule, the level of output of each of the CFC-using industries is
held constant.
1 2
' For "switch" prices such as p and p , the quantity of CFCs demanded is
t t
1
indeterminate. For example, at a price of p , the quantity of CFCs demanded
0 ' 1 t
may range from q to q . At prices other than these switch prices, however, the
t t
quantity of CFC demanded is determinate.
-------
1-14
EXHIBIT 1-5
EFFECTS OF A SHIFT IN THE CFC SUPPLY CURVE
(a) Market for CFC
Price of
CFC in
Year t
d°
Quantity of
CFC in Year t
Price of
Output
in Year t
Pi
(b) Market for Output of a
CFC-Using Industry
Quantity of
Output in Year t
-------
1-15
Panel (b) shows the output market of a single CFC-using industry (recall
that there are many such industries). The demand curve for the output is drawn
as being vertical "over the relevant range. The dashed portions of the demand
schedules are those outside the relevant range and no assumptions are made about
the shape of the demand schedule over these ranges. As before, the output
supply schedules are drawn as upward sloping."
The effect of the higher CFG price due to the upward shift in the CFG
supply curve is to push up the output supply curve from S to S . This raises
the equilibrium price of output from P to P , but, given the shape of the
relevant portion of the demand curve, it does not alter the equilibrium
quantity of output, which remains at Q . Because the aggregate derived demand
schedule for CFC in panel (a) is specified holding output levels constant, there
is, therefore, no "feedback" contraction of the derived demand schedule. Thus,
the new equilibrium in the Input market is simply given by the intersection of
S^- and the existing aggregate derived demand schedule, while the new
equilibrium in the output market is given by the intersection of S^ and the
output demand schedule.
1,6 Measuring Social Costs in the Input and Output Markets
The welfare measures relevant to the calculation of .the economic costs of a
regulation are producer surplus and consumer surplus:
o Consumer surplus is a measure of the difference between
what consumers are willing to pay for a good and what they
have to pay for it. As such, it indicates the net gain to
consumers of being able to buy all units of the good at
the prevailing price. In graphical terms, consumer
surplus is given by the area under a demand curve above
the price line.
o Producer surplus is a measure of the difference between
the price firms received for their output and the price at
which they are willing to supply the output. Thus, it is
a measure of the net gains to firms of being able to sell
all of their output at the prevailing price. In graphical
terms, the aggregate producer surplus of a competitive
industry is given by the area above the industry's supply
curve under the price line.
Panel (a) of Exhibit 1-6 shows consumer surplus under the aggregate derived
demand schedule for CFCs. There is no producer surplus in the CFC market
because of the assumption that price equals marginal cost and that CFC supply is
perfectly elastic. Panel (b) shows consumer and producer surpluses in the
o
We do not have data on the shapes of these output supply curves. But
upward sloping curves are not inconsistent with the assumption that the
CFC-related portion of the production process is of the fixed-proportions
variety.
-------
1-16
EXHIBIT 1-6
ILLUSTRATION OF CONSUMER AND PRODUCER SURPLUS IN
THE CFC AND CFC-USIHG PRODUCT MARKETS
(a) Market for CFC
Price of
CFC in
Year t
Consumer
Surplus
Quantity of
* C in Year t
Price of
Output
in Year t
(b) Market for Output of a
CFC-Using Industry
, sf//f/f/////s//s
,////////////M^^
^Plllp^
'-\
NX
Consumer
Surplus
Producer
Surplus
Quantity of
Output in Year t
-------
1-17
output market of a CFC-using industry. Consumer surplus is not well-defined in
this panel since the shape of the demand curve is specified over only a small
range.
The social costs of an increase in the price of CFCs due to higher
production costs can be measured in terms of the changes in consumer surplus in
the CFC market or the changes in producer and consumer surplus in the output
markets. Panel (a) of Exhibit 1-7 shows the effect in the CFC market of an
increase in CFC price from p to p . Consumer surplus under the aggregate
derived demand schedule falls by an amount equal to the irregularly-shaped area
C. Thus, the net social cost of the CFC price increase is given by area C.
Panel (b) of Exhibit 1-7 shows the change in producer and consumer surplus due
to the CFC price increase in an output market. Consumer surplus in this market
falls by an amount equal to the rectangular area D+E. The change in producer
surplus is equal to the difference between the lower triangular area F+G and the
upper triangular area D+F; this difference is area G-D. If the higher CFC price
simply results in a parallel shift in the output supply curve, area D is equal
to area G and there is no change in producer surplus.
The net change in the sum of producer and consumer surpluses in the output
market is equal to area D+E plus area G-D, which is areas E+G. Thus, the cost
of the CFC price increase in this particular output market is equal to area E+G.
Given the links, between the CFC market and the output markets of the
CFC*using industries, we would expect some relationship between the social cost
measures in the two sets of markets. In fact, area C in the CFC market is equal
to the sum of the E+G areas in all the ^atput markets of the CFC-using
industries.1° Thus, the social cost of a change in CFC price can be measured in
either the CFC market or the relevant output markets. Given the nature of the
data collected as part of this analysis, it is far easier to measure costs in
the CFC market.
1.7 Social Versus Private Costs
In the discussion thus far, no distinction has been made between the private
costs of undertaking an action to reduce CFC use and the social costs of such an
action. The distinction is unnecessary if private and social costs are
identical. However, there are two reasons why the two costs measures diverge:
o businessmen are concerned only with their profits after
taxes while society is concerned with total costs
including taxes and
" If the price exceeds marginal cost in the CFC-using industry, then
additional social costs are incurred, equal to the reduction in CFC production
times the amount by which price exceeds marginal cost.
10 See R. E. Just, D.L. Hueth, and A. Schmitz (1982), Applied Welfare
Economics and Public Policy. Prentice-Hall, Englewood Cliffs, New Jersey,
Chapters 4 and 9.
-------
1-18
EXHIBIT 1-7
CHANGES IN CONSUMER AND PRODUCER SURPLUS
DUE TO AN INCREASE IN CFC PRICE
(a) Market for CFC
Price of
CFC in
Year t
d°
Quantity of
CFC in Year t
(b) Market for Output of a
CFC-Using Industry
Price of
Output
in Year t
Quantity of
Output in Year t
-------
1-19
o the private discount rate exceeds the social discount
rate.
The first factor implies that social costs exceed private costs if the firm's
tax burdens are reduced by the CFC regulations. The second factor implies
relatively higher private costs because the amortized value of capital
expenditures increases with a higher discount rate.
Because the primary purpose of the cost analysis described in this appendix
is to determine the social costs of the proposed regulations, the relevant cost
measure is the social one. Thus, the final cost estimates are based on the real
before-tax costs of industry responses to the proposed regulations. However," to
assess potential industry responses, private costs are the relevant measure
because they determine the choice of control options by CFC-using firms. In
evaluating alternative control options, these firms will compare the private
(rather than the social) costs of the options.
In terms of the supply and demand relationships discussed earlier, the
divergence between private and social costs is accommodated in the following
manner:
o The ordering of technologies along the steps of the
derived demand schedules for CFC is always based on
private costs. This is consistent with firms choosing
technologies on the basis of private costs.
o The aggregate derived demand schedule used to determine
equilibrium prices and quantities in the C^C market is
based on private costs.
o The aggregate derived demand schedule under which changes
in consumer surplus are measured is expressed in terms of
social costs. That is, for each of the underlying derived
demand schedules, the heights of each of the steps in the
demand schedules reflect social rather than private costs.
Thus, for each CFC compound there are two sets of derived demand schedules:
one reflecting private costs and another reflecting social costs. The two sets
of demand schedules differ only in terms of the heights of the steps; the
correspondence between technologies and steps is identical for the two sets.
2. ANALYSIS OF THE REGULATORY ALTERNATIVES
There are four basic regulatory alternatives for controlling the use of
CFCs: a regulatory fee on CFCs; auctioned permits for CFC use; quotas on CFC
production; and engineering restrictions and product bans on the use of CFCs in
particular applications. Combinations of these alternatives may also be used.
Each of these alternatives is analyzed below in terms of the framework developed
in Section 1. For purposes of exposition, a stylized version of each of the
regulatory alternatives is analyzed. The actual alternatives being considered
are considerably more complex, but their salient features are captured by the
constructs employed here.
-------
1-20
2.1 Regulatory Fees on CFCs
The regulatory fee alternative under consideration is simply a constant fee
imposed on producers of virgin (i.e., non-recycled) CFCs. The fee may differ
across CFC compounds depending on their ozone depletion potential.
The basic effect of a fee is to raise the price of CFC faced by users. This
is illustrated in Exhibit 1-8. The fee pushes up the supply curve for CFC by an
amount equal to the fee itself. The effect of this shift is to raise the
equilibrium price of CFCs and to lower, the equilibrium quantity. As shown, the
equilibrium price rises from p to p and the equilibrium quantity'falls from
01 1
q to q . At the new equilibrium, the price paid by users of CFC is p and,
0
given the horizontal supply curve, the price received by sellers is p . The
difference between the two prices is the regulatory fee per unit of CFCs.
The rectangular area A in the exhibit represents the revenue generated by
the fee. It is equal to the difference between the price paid by users at the
new equilibrium and the price received by suppliers times the new equilibrium
quantity. The revenue generated comes out of the producer surplus of the
CFC-using industries and the consumer surplus of the buyers of the outputs of
these industries. ^ However, the revenue generated offsets some of the losses
experienced by these parties, hence the revenue is a transfer from the affected
parties to the government. It does not represent a net social cost.
The net social cost of the fee is given by the irregularly shaped area B in
Exhibit I-'8. The costs captured by this area are borne by the same set of
parties as those identified above. Because of the horizontal supply curve for
CFCs and the assumption that price equals marginal cost, there are no losses (in
terms of producer surplus) experienced by the producers of CFCs or the owners of
the factors used in its production.
2.2 Auctioned Pernits for CFC Use
The auctioned permit alternative would require firms to purchase permits in
order to use CFCs. The total number of permits available would be set by EPA.
The permits would initially be allocated via an auction, but firms would
subsequently be allowed to buy and sell permits from one another. The permits
would not be defined by CFC compound, but in terms of ozone depletion
equivalents. For example, if the ozone depletion potential of CFC-11 is taken
as the base, then using ten kilograms of CFC-11 would require purchasing permits
worth 10 kilograms. Fewer permits would be needed to use ten kilograms of a CFC
H Losses in producer surplus occur to the extent that the higher CFC price
induces consumers to switch to substitute non-CFC based outputs. Given the
assumption that the supplies of all inputs are perfectly elastic, no losses
accrue to the owners of the factors employed in the CFC-using industries.
-------
1-21
EXHIBIT 1-8
SOCIAL COSTS OF A REGULATORY FEE ON CFC
Price of
CFC in
Year t
i
Pt
o
P?
^ transfer
S^ 1
t "
I ^s net social costs
fee A ^
*
|
T _ 0
1
o Quantity of
q l CFC in Year t
-------
1-22
that is less ozone depleting than CFC-11, and more permits would be needed to
use one that is more ozone depleting. Thus, there would be a single permit
market for all CFC compounds instead of separate markets for each compound.
To model the market for permits that would develop under this regulatory
alternative, it is necessary, first, to specify the conduct of the market.
Given the large numbers of firms that use CFC compounds and would participate in
the market, it may be reasonable to assume that the market is a competitive one.
Although this is the assumption adopted in the analysis, alternative assumptions
are possible. *
The second step is to determine the aggregate demand for permits. Because
the permits are based on ozone depletion equivalents, it is necessary to
translate the demands for the various CFC compounds into ozone depletion
equivalents and then sum these translated demands. Conceptually, this is
accomplished by multiplying the vertical and horizontal scales on the aggregate
derived demand schedule for each CFC compound by its corresponding ozone
depletion index. The individual aggregate derived demand schedules for
different CFCs are then measured in the same units. These aggregated derived
demand schedules can then be horizontally summed to obtain a single "composite"
aggregate derived demand schedule for permits defined in terms of ozone
depletion equivalents.
This composite demand schedule is depicted in Exhibit 1-9 along with a
vertical line representing the total number of permits available at a given
time." The intersection of this line with the demand schedule gives the
composite "full" price, r , paid for CFCs in terms of their ozone depletion
equivalents. This composite full price can be translated back to a full price
for each CFC compound (in standard units) by dividing the composite full price
by the ozone depletion index for the compound.
The result is illustrated in Exhibit I-10 for a single CFC market. In
addition to the standard'aggregate demand and supply schedules, a line
representing the full price for this CFC compound is presented. The full
1
price, p , is the price paid by users of the CFC for both the compound itself
The highly-concentrated CFC-producing industry could lead to a
highly-concentrated market for permits. In such a case, the observed market
price for the permits would be below their true value, and the transfer payments
would flow to the holders of the permits instead of to the permit-issuing agency
(presumed to be the government). Assuming that the same non-competitive market
behavior exists both before and after the permits are auctioned, the assumption
of a competitive market for permits does not bias the estimates of net social
costs.
13 The above discussion implicitly assumes that the number of permits
issued is binding. In other words, the level of CFC use allowed under the
permit scheme is lower than that in the absence of regulations. The permit
scheme would otherwise be redundant and permits would have no value.
-------
1-23
EXHIBIT 1-9
MARKET FOR PERMITS IN OZONE DEPLETION EQUIVALENTS
Composite Price
in Year t
Composite
full price
Permits Available
Composite Aggregate
~ Derived Demand
Composite Quantity
in Year t
-------
1-24
EXHIBIT 1-10
SOCIAL COSTS OF AUCTIONED PERMITS FOR CFC USE
(full
(CFC
Price of
CFC in
Year t
. i
price) pt
. n
price) pj
- •
.x transfer
t ^
\ rift <:nrial rn«r«
permit A x —
price ^
R
s°
0 Quantity of
l CFC in Year t
-------
1-25
0
and the permits required to use it. The price of the CFC is given by p ; this
is the price received by the producers of the compound. The price of a permit
is equal to the difference between the full price and the price received by the
producers.
The total amount spent on permits is given by the rectangular area A. This
area is simply equal to the permit price times the quantity of the CFC demanded
at the full price. As in the case of a regulatory fee, the permit payments
represent a transfer from one firm to either another firm or to the government.
As.such, permit payments are not counted as net social costs.
The net social costs of the permit scheme are given by the irregularly
shaped area B. These costs are borne by the same set of parties as those in the
regulatory fee case. Once again, because of the horizontal supply curve for CFC
and the assumption that price equals marginal cost, there are no losses
experienced by the producers of CFC or the owners of the factors used in its
production.
2.3 Allocated Quotas
Under the allocated quota alternative, producers and importers of CFCs would
be issued quotas based on their historical market shares. They would then be
allowed to trade the-s quotas among themselves. Like the auctioned permits,
these quotas would be defined in terms of ozone depletion equivalents.
Conceptually, the allocat d quota and auctioned permit alternatives are very
similar. The major differences between them are: (1) allocated quotas are
targeted specifically at producers/importers, whereas auctioned permits are also
bought and sold by CFC users; and (2) quotas are initially issued free, whereas
auctioned permits are auctioned off by EPA.
Because the allocated quotas can be traded, the analytical procedure for
determining the social costs of allocated quotas is identical to that for
auctioned permits. The differences noted above only affect the magnitude of the
transfers under the two alternatives, and the parties across which they take
place. In terms of the framework outlined in the previous section for measuring
the costs of a auctioned permit scheme, the total number of quotas issued
corresponds to the available number of permits and the quota price corresponds
to the permit price.
2.4 Comand and Control Alternatives
The two major command and control alternatives being considered are:
o mandatory adoption by some industries of specific
engineering controls; and
o bans on the use of CFCs in selected products.
-------
1-26
The procedure for calculating the costs associated with the first alternative is
straightforward. Because it is not necessary to first determine the response of
the CFG-using industries to the regulations (unlike the case for the economic
incentive based alternatives), the cost analysis entails tabulating and summing
the social costs of implementing the required engineering controls.
The method for determining the costs of bans on CFC use in specific products
is also straightforward. The costs can be determined by measuring the consumer
surplus under the derived demand schedule of the industry producing the banned
output. Exhibit I-11 depicts the derived demand schedule and associated
consumer surplus for an industry manufacturing a banned product. To reduce CFC
use in the product to zero, the industry must implement all the control options
to the left of the one employed in the baseline. Hence, all consumer surplus in
this market is lost. None of this loss is a transfer. "Therefore, the costs of
the regulation are equal to the baseline consumer surplus, represented by area A
in Exhibit I-11. ** As in the previous cases, the loss comes out of the producer
surplus of the CFC-using industries and the consumer surplus of the buyers of
their output.
3. EMPIRICAL APPROACH FOR ESTIMATING COSTS OF REGULATION
This chapter describes the manner in which the framework presented in the
previous chapter was implemented to estimate the social and private costs of
U.S. regulations aimed at reducing the domestic use of CFCs. To compute the
social and private costs of reg- lations, demand schedules for CFCs were
estimated that define the amount of CFCs that would be demanded in each of the
major CFG applications (i.e., industries) at higher CFC prices. With these
schedules, the costs of regulations chat restrict domestic CFC use were
estimated as changes in consumer and producer surplus.
The demand schedules were estimated from engineering cost data developed for
EPA. ^ These engineering data describe the capital and operating costs of
options for modifying the manner in which products are produced and/or used in
order to reduce the use and/or emissions of CFCs. These options for reducing CFC
use and/or emissions have been variously referred to as "control options,
control possibilities, technical possibilities, and alternative technologies."
In the previous sections of this appendix, the opportunities for reducing CFC
use were discussed in terms of alternative "fixed proportion production
technologies." In this chapter, all the above terms are considered to be
interchangeable.
The data upon which the derived demand schedules are based describe the
steps that firms may take in response to increased CFC prices. These steps
include using alternative production methods, using alternative chemicals,
1* Because the supply curve for CFCs is perfectly elastic, the price of
CFCs does not change in response to the lower demand for CFCs resulting from the
ban. Hence, there are no changes in non-banned markets. This would not be true
if the supply curve for CFCs were upward sloping. It would then be necessary to
examine non-banned markets.
" The engineering data are described separately in a series of addenda to
the RIA, found in Volume III.
-------
1-27
EXHIBIT 1-11
SOCIAL COSTS OF A PRODUCT BAN
Price of CFC
in Year t
P?
Derived Demand Schedule of
Industry Producing Banned Product
Quantity of CFC
in Year t
-------
1-28
installing equipment to collect and recycle CFCs, and switching to non-CFC
products. The increased prices of CFCs (caused by the restrictions imposed by
the regulation) are assumed to drive the adoption of these steps by firms.
Based on the derived demand curves developed from the engineering data,
social costs are evaluated using pre-tax costs discounted at a social discount
rate. Private costs are evaluated using after-tax costs discounted using a
private after-tax discount rate.
The steps used to estimate costs are as follows:
1. Identify Major CFC Applications. The major CFC
applications were identified and divided into key product
areas. The patterns of CFC use in each application were
defined.16
2. Specify Control Possibilities Applicable in Each
Application. A wide range of control possibilities was
identified for each of the application categories. Some
controls are available today, while others are expected to
become available in the future. For each of the control
possibilities, the potential cost of undertaking the
control and the influence that the control may have on CFC
use and emissions was defined.
3. Estimate CFC Use Reductions Achievable with Each Control
Possibility. The annual reduction in CFC use that can be
achieved if the control possibility wer. implemented was
estimated for each control individually, using the 1985
pattern of use.
4. Estimate Annualized Costs of the Control Possibilities.
Social and private annualized costs of the control
possibilities were estimated from the capital and
operating data provided. One-time costs (such as capital
costs) were converted into equivalent annual costs using a
standard annualization factor. The annualized costs were
expressed in terms of dollars per kilogram of CFC use
avoided by dividing the annualized cost estimate by the
number of kilograms of CFC use that are avoided by
implementing the control.
5. Construct Derived Demand Schedules for Each Application.
Derived demand schedules were constructed for each
application using subsets of the control possibilities.
The subsets of the control possibilities were selected to
represent groups of options that may be undertaken over
time in response to increased prices of CFCs. The groups
represent internally consistent sets of steps that may be
undertaken within each of the applications.
1° The definitions of the CFC applications and their products are
presented separately in addenda to the RIA, found in Volume III.
-------
1-29
The general shape of these schedules is shown in Exhibit
1-4. The height of each vertical step in the schedules
represents the annualized costs of each control
possibility (on a per kilogram basis). The width of each
horizontal step represents the reduction in annual CFG use
associated with the controls. Different schedules were
developed for: (1) social and private costs, and (2) each
year in the analysis period reflecting the expected future
availability of control possibilities over time.
6. Aggregate Derived Demands for CFCs. The derived demand
schedules for each of the applications were summed
horizontally to estimate aggregate derived demand.
7. Estimate Private and Social Costs. The social and private
costs of regulatory alternatives were computed by
comparing the required reduction in CFC use to the
aggregate derived demand schedule. The changes in consumer
surplus were estimated using both the private and social
derived demand schedules, resulting in estimates of the
private and social costs of the required reduction.
Each of these steps is described below, followed by a description of major
limitations.
3.1 Identify Major CFC Applications
The major uses of CFCs are in:
o refrigeration;
o foam blowing;
o fire extinguishing;
o solvent cleaning;
o sterilization; and
o miscellaneous applications.
For this analysis, these broad end-uses were divided into more detailed
application categories that differentiate the types of products made with CFCs.
A list of these applications is shown in Exhibit 1-12 along with estimates of
the 1985 CFC use in each.
The applications were defined as products (e.g., insulating foam) or
services (e.g., metal cleaning). In some cases a single product is divided into
separate applications. For example, two applications are defined for boardstock
rigid polyurethane foams -- construction and industrial. Although the
manufacturing processes and firms producing foams for both applications are
similar, a division between the two was kept in order to capture possible
differences in control options available for each.
-------
1-30
EXHIBIT 1-12
LIST OF CFC APPLICATIONS USED IN THE ANALYSIS
1985 Use
Application
FOAM BLOWING
Rigid Polvurethane Foam
Laminated- Construction
Boards tock- Cons truction-Bldg.
Boards tock- Construction- Ind.
Poured-Refrigeration
Poured- Packaging
Poured- Transportation
Poured- Cons tt uc tion- Bldg .
Poured- Construction- Ind.
Poured- Cons truction-Bldg.
Poured- Construction- Ind.
Sprayed-Transportation
Flexible Polvurethane Foam
Slabstock
Molded
Compound
CFC -11
CFC -11
CFC -11
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC-ll/CFC-12
CFC -11
CFC -11
(million of kiloerams)
12.8
2.7
0.2
9.2
3.4
3.4
' 3.2
0.5
8.0
3.0
1.3
11.5
3.3
Phenolic Foam
Polypropylene Foam
Polyethylene Foam
PVC Foam
Extruded Polystyrene Foam
Sheet
Boardstock
CFC-ll/CFC-113
CFC-ll/CFC-114
CFC-ll/CFC-114
CFC-ll/CFC-12
CFC-12
CFC-12
1.4
1.9
3.1
6.3
3.0
-------
1-31
EXHIBIT 1-12 (continued)
LIST OF CFC APPLICATIONS USED IN THE ANALYSIS
1985 Use
Application Compound (million of kilograms)
REFRIGERATION
Mobile Air Conditioners
Retail Food
Cold Storage
Centrifugal Chillers
Refrigerators
Transport
Process Refrigeration
Freezers
Reciprocating Chillers
Dehumidifiers
Ice Machines
Water Coolers
Vending Machines
Centrifugal Chillers
Centrifugal Chillers
Centrifugal Chillers
Retail Food
Cold Storage
SOLVENTS
Conveyorized Vapor Degreasing
Open Top Vapor Degreasing
Cold Cleaning
Dry Cleaning
STERILIZATION
Hospitals
Medical Equipment
Contract Sterilization
Pharmaceutical
Spice Fumigant
Commercial R&D Labs
Libraries
Non-commercial R&D Labs
Animal Labs
Bee Hive Fumigant- -DOA
CFC- 12
CFC -12
CFC -12
CFC -12
CFC -12
CFC- 12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -11
CFC -114
CFC -500
CFC -502
CFC- 502
CFC- 113
CFC -113
CFC-113
CFC -113
CFC -12
" CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
CFC -12
54.1
4.7
2.6
2.0
1.8
0.7
0.7
0.5
• 0.4
0.3
0.2
<0.1
<0.1
5.5
0.8
0.9
6.2
3.0
18.1
15.9
4.6
1.4
6.9
3.1
1.3
0.6
0.2
0.1
<0.1
<0.1
<0.1
<0.1
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1-32
EXHIBIT 1-12 (continued)
LIST OF CFC APPLICATIONS USED IN THE ANALYSIS
Application
Compound
1985 Use
(million of kilograms^
FIRE EXTINGUISHING
Total Flooding Systems
Civilian Electronic
Military
Civilian Flammable Liquid
Civilian Other
Civilian Electronic
Military
Civilian Flammable Liquid
Civilian Other
Portable Systems
Civilian Electronic
Military
Civilian General
Civilian Residential
Civilian Flammable Liquid
Military
Locally Applied Systems
Locally Applied Systems
MISCELLANEOUS
Skin Chiller/Cleaner
Liquid Food Freezing
Blower Cleaner
Warning Devices
Heat Detectors
Whipped Topping Stabilizer
Aerosol Propellant
Halon
Halon
Halon
Halon
Halon
Halon
Halon
Halon
1211
1211
1211
1211
1301
1301
1301
1301
Halon 1211
Halon ??11
Halon 1211
Halon 1211
Halon 1211
Halon 1301
Halon 1211
Halon 1301
CFC-113
CFC-12
CFC-12
CFC-12
CFC-12
CFC-115
CFC-ll/CFC-12
2.2
0.5
0.4
0.3
1.3
0.8
0.2
0.2
0.1
0.1
3.0
0.9
0.6
0.9
0.1
9.5
Source: See addenda to the RIA, Volume III.
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1-33
The applications cover all CFC use associated with manufacturing,
installation, and use of the application. ' Mobile air conditioners, for
example, require CFCs during manufacturing, installation, and for replacing CFCs
lost during product use. Manufacturing, installation and service use of CFCs
are each analyzed within this application, recognizing that the control
possibilities may influence each portion of the use separately from the other
portions.
For some applications, the output produced can best be described as a
"service." Examples include solvent and sterilization uses. For service uses,
applications were defined by the entity performing the service (e.g., hospitals
sterilizing surgical equipment) or the type of service being performed (e.g.,
conveyorized vapor degreasing).
3.2 Specify Control Possibilities Applicable in Each Application
Having identified the primary applications of CFCs, the next step was to
define the set of control possibilities that may be undertaken for purposes of
reducing CFC use within each application. The following types of control
possibilities were identified:
o- Product substitutes -- replace CFC-consuming products with
non- (or less-) CFC-consuming substitute products. An
example is substituting packaging materials manufactured
using 3FC-blown foam with paper-based packaging materials.
o Chemical substitutes -- replace CFCs used in the
manufacture, installation, or use 01 products with less
ozone depleting chemicals.
o Process substitutes and other controls -- process changes,
use of add-on recovery/recycling equipment, and other
kinds of controls for reducing CFC use or emissions (e.g.,
recovery of CFCs from existing products).
For the 74 applications identified in this analysis, a total of nearly 900
control possibilities were identified.^° These controls form a "menu" of
actions from which firms within each of the applications may choose to reduce
their consumption of CFCs. Although the identification of control possibilities
was designed to be as comprehensive as possible, additional options may be
available that are not included in the data available for this analysis.
1' The available application data do not account for the total amount of
CFC produced, imported, and exported in the U.S. The difference between the sum
of the use across all the application data and the total amount produced is
referred to as "unallocated use."
^ The data on the control possibilities are documented separately in
addenda to the RIA, found in Volume III.
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1-34
Of note is that not all of the options identified are available immediately.
For each control option -an estimate was made of its expected future availability.,
over time. The following definitions were used:
o short term - - available in 0 to 3 years;
o medium term -- available in 4 to 7 years; and
o long term -- available in more than 7 years.
Of the nearly 900 control possibilities identified, about 350 were excluded
from further analysis because of factors that make the controls unacceptable for
use by industry, including:
o risk/toxicity;
o technical feasibility;
o cost;
o effectiveness at reducing CFG use;
o enforceability; and
o insufficient dsra to evaluate the costs and reduction
achieved by the substitute.
For the remaining approximately 550 control options identified, detailed
estimates were prepared concerning the cost of undertaking the control and the
possible reduction in annual CFC use achievable with the control over time.
These factors were used to estimate the annualized cost of the control per.
kilogram of use avoided, which is used to estimate the appropriate derived
demand schedules.
3.3 Estimate CFC Use Reductions Achievable with Each Control Possibility
The potential effectiveness of each control possibility to reduce CFC use
was estimated within its application category based on three factors:
o the portion of the application for which the control is
effective;
o the reduction potential of the control; and
o 1985 U.S. CFC use and emissions within the application.
The portion of the application for which the control is effective defines
the segment of the application that may reduce its CFC use through the
implementation of the control. For example, the mobile air conditioning
application includes several types of use, including service use. The control
being analyzed may be applicable for the service use segment of the application,
but may not be applicable for the other segments. In this case, the control is
analyzed as being capable of reducing only the climate service use, and the
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1-35
other uses are assumed to be unaffected. This case is further refined in that
the control may apply only to a portion of the service use segment (e.g., only
larger automotive repair shops). In this case, the control is analyzed as being
capable of reducing only a portion of the service use, and the remaining service
use is assumed to be unaffected.
%
An alternative example is the case where a chemical substitute is estimated
to be applicable to only a portion of the total application's use of CFCs. The
portion for which the chemical substitute is not applicable may have certain
product characteristics or manufacturing requirements that preclude the use of
the substitute. In this case, the chemical substitute is assumed to be capable
of replacing only the applicable segment of the application, and the
non-applicable segment is assumed to be unaffected.
Reduction potential refers to the extent to which a control reduces CFC use
in its applicable segment of the application. For example, recovery equipment
used during mobile air conditioning servicing may result in a fraction of
service use being recycled, thereby reducing total use in the application. In
this example, only the fraction of the use that is recovered is counted as a
potential reduction in compound use. The reduction potential is generally less
than 100 percent for engineering cpntrols. The reduction potential for chemical
substitutes was assumed to be 100 percent (within the applicable segment of the
application) because chemical substitutes generally result in a complete
replacement of a CFC. ' Similarly, the reduction potential for product
substitutes is 100 percent.
The final factor considered is the use and emissions of the compound in the
applications. The 1985 use in the application is divided into manufacturing
use, installation use, service use, other use, and unallocated use. The total
use in the application equals the sum of these component uses. The total use in
some applications could not be allocated to manufacturing, installation, or
service. In this case, an amount was identified as "other or unallocated," and
unless specifically assumed otherwise, this portion of the use was assumed to be
controllable to the same extent as the allocated portion of CFC use in that
control option.
Emissions in 1985 are divided into emissions during manufacturing,
installation, product use and servicing, product disposal, and "other"
emissions. Engineering controls are assumed to reduce CFC emissions in these
categories. As with unallocated use, "other" emissions were assumed to be
controllable to the same extent as allocated emissions.
Given these definitions, the approach used to estimate the potential for
control options to reduce CFC use differed by the type of control as follows:
o Product substitutes were assumed to reduce CFC use during the
manufacturing and installation of CFC-consuming products they
replaced. Therefore, the use reduction of product substitute
1" Some of the chemical substitutes are themselves potential ozone
depleters. The increase in the use of these compounds as a consequence of the
undertaking of the control option is identified as well.
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1-36
controls was estimated by multiplying the 1985 compound use
during manufacturing and installation in the application
category by the estimated portion of the manufacturing and
installation use to which the product substitute applies.
o Chemicat substitutes may be capable of replacing CFC use in:
(1) manufacturing and installing new products (e.g., making a
new refrigerator) and/or (2) servicing existing products
(e.g., replacing CFCs while servicing an old refrigerator).
Therefore, separate use reductions were estimated for chemical
substitutes in new products and in existing products. The
use reduction associated with chemical substitute in new
products was estimated by multiplying the portion of new
production that may adopt the chemical substitute by the 1985
CFC use during manufacturing and installation. Similarly, for
existing products, the reduction potential was estimated by
multiplying the portion of existing products for which the
substitute may be applicable by the 1985 CFC use for service
existing products.
o For process substitutes. add-on engineering controls, and
other kinds of controls, 'use reduction potentials were
calculated as the sum of the reductions possible in each of
the emissions categories. The separate emissions reductions
estimates for the emissions categories (i.e., manufacturing,
etc.) were multiplied by the 1985 emissions estimates to
estimate the total.
The estimates of the portion of the application to which each control
applies were allowed to change over time. A maximum level was defined,
indicating the likely full extent to which the control would be implemented in
the application, given time for the firms in the application to implement the
controls.' The time required to implement the controls was also estimated (and
is generally on the order of 2 to 10 years), so that the estimated use reduction
changes over time as the level of applicability of the control increases. For
purposes of this analysis the increase in the applicability of the control over
time is modelled using linear interpolation, so that the maximum likely
penetration is reached in the time required for firms to adopt the control.
3.4 Estinate Azmualized Costs of the Control Possibilities
For each control possibility, both social and private annualized costs were
estimated. These annualized costs reflect the capital, operating, and other
costs that are incurred when the control is undertaken. These costs are based
on engineering estimates and are defined as the costs that are incremental
relative to continuing to manufacture and use the CFC-related products in their
current forms. The social costs reflect the total resource costs to society,
and the private costs reflect the costs faced by firms, including appropriate
adjustments for tax liabilities and costs of capital.
To enable the controls to be compared and analyzed in relation to a policy
of restricting the use of CFCs, the annualized costs are expressed on a per
kilogram of use avoided basis. This "per kilogram" estimate is made by dividing
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1-37
the annualized cost of undertaking the control by the amount of the compound use
that may be reduced by the control. The resulting value (based on private
costs) is taken as an indication of the increase in the price of CFCs that would
be required in order for firms to be indifferent between undertaking the control
or continuing to use the CFCs. If the price of the CFCs exceeds this annualized
value, the firm would be better off to reduce its use of CFC and undertake the
control. Consequently, the cost estimates are designed to be used in the
analysis framework described in the previous chapter, where derived demand
schedules form the basis of the analysis.
The following types of costs were reported (where applicable) for each
control possibility:^
o capital costs - - such as the acquisition cost of equipment
required to convert production capacity to use substitute
chemicals. Capital costs are one-time costs that are
subject to depreciation.
o non-recurring costs -- transitional, one-time costs such
as research and development, reformulation, or training
required to implement ~a control. For purposes of
computing private annualized costs, non-recurring costs
were considered not to be depreciable.
o annual operating costs -- incremental materials, and labor
required to implement the control.
o salvage of capital equipment -- residual value of
equipment used to implement a control. 1
o annual offsetting savings -- reduced expenditures due to
lower use of CFCs and other factors.
In addition to the costs identified above, several special costs were
reported for product and chemical substitutes:
o Product substitutes.
the price differential between the CFC-using product
and its replacement product was included as a cost (or
possibly a savings); and
for insulating foams, an estimate was made of the
potential stream of annual energy losses caused by the
use of less-well-insulating products.
™ Not all of these cost categories apply to all of the controls. Some
chemical substitutes, for example, can be used without additional capital
investment.
21 A salvage value for necessary capital equipment was included
in only a few instances.
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1-38
o Chemical substitutes - - the expected future price per
kilogram of CFC-replacing chemicals was estimated along
with the amount of the substitute needed to replace a
single kilogram of CFC.
All of these reported engineering-based cost estimates are on a before-tax, real
basis in 1985 U.S. dollars.
3.4.1 METHODS FOR COMPUTING SOCIAL ANNUALIZED COSTS
Estimates of capital and non-recurring costs were annualized by multiplying
these costs by:
r t
1 - [!/(!«)]
where r is the real social discount rate and t is the estimated economic life of
capital. This factor is used to spread capital and non-recurring costs over the
economic life of the capital to which a control is applied. The economic life of
the capital equipment for each control was estimated, and ranged' between 5 to 20
years.
Non-recurring costs (such, as research and development costs) represent
one-time costs which, in practice, will not be replicated in future years. Using
this interpretation, such non-recurring costs should not be included in
annualized costs because they will not recur at a constant scale (i.e., the
costs only occur once, regardless of how long the control is undertaken).
Nonetheless, non-recurring costs were included with capital costs so that the
annualized cost estimates would reflect the full social costs of controls.
To compute total annualized costs, annualized capital and non-recurring
costs were added to estimates of other annual pre-tax costs as follows:
o annual operating costs -- annual operating costs such as
labor and utilities were added directly.
o salvage of control equipment -- few controls were expected
to have salvageable capital. The present value of the
salvage value of control equipment was estimated as:
S * C/(l+r)c
where S is the percentage "of capital costs estimated to be
recoverable on salvage, C is the original capital cost, t
is the useful life of capital, and r is the real social
discount rate. This present value salvage amount was
annualized in the same manner as described above for
capital and non-recurring costs. The resulting annualized
salvage value was then deducted from total annualized
costs.
o annual savings -- the estimated annual savings due to
reduced CFC use, operating efficiencies, or other factors
associated with implementing a control were subtracted
from total annualized costs.
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1-39
In addition to these cost components, adjustments are required for product
substitute and chemical substitute controls. For product substitutes, the
differential costs of the products and their differences in lifetimes must be
reflected. 2 The annualized cost associated with replacing one CFC-related
product was estimated as:
-Pc -i- Ps *
where: PC - the 1985 price of the CFG -based product;
Ps - the 1985 price of the product substitute;
tc - the average useful life of the CFC-based product;
ts - the' average useful life of the product substitute; and
r - real social discount rate.
This annualized cost was added to the annualized costs computed above.
For substitute insulating materials, the costs of reduced insulating
capacity was reported in terms of the annual incremental energy costs
experienced per metric ton of CFC -blown foam replaced. Because these energy
costs occur during each year for which alternative insulating materials are
used, annual energy costs were aggregated to reflect the stream of costs
incurred over the useful life of the product as follows:
PV(E) - E *
with r representing the real social discount rate, t the life of the CFC-blown
foam product, and E the real before-tax annual energy penalty. This energy cost
value was added to the annualized cost estimates described above.
The adjustment to the annualized cost estimate for chemical substitute
controls was based on two factors: (1) the price of the chemical substitute
compared to the price of the CFC it replaces and (2) the amount of substitute
required to replace a unit of the CFC. These factors were combined to estimate
the relative cost of replacing one kilogram of the CFC with the substitute as:
Ps * R - PC
where Ps is the price of the chemical substitute, R is the number of kilograms
of substitute required to replace one kilogram of the CFC, and PC is the price
of the displaced CFC. Separate estimates of R were made for chemical
22 The difference in the lifetimes of the CFC-related product and the
substitute product must be incorporated so that the relative cost of switching
to the substitute can reflect the costs over the full lifecycle of the products.
If the substitute product lasts longer than the current CFC-related product,
then the cost of switching is reduced; if the product life of the substitute is
shorter, then the cost of switching is increased. In general, the reported
lifetime differences were small, so that the lifetime adjustment had a small
impact on the cost estimate.
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substitutes in new and existing products. Annual chemical replacement costs
were added to annualized capital, operating, and other costs of chemical
substitutes (if any). As a final step, the annualized costs were adjusted to
reflect differences in the basis for expressing the engineering cost estimates,
which included:
o Costs reported for the maximum fraction of the application
expected to take the control. In this case the cost
estimates are based on the segment of the application
expected to implement the control, and consequently no
adjustment was required.
o Costs reported per unit of application (e.g., per metric
ton of foam produced). In this case the costs had to be
multiplied by the number of units (e.g., the number of.
metric tons of foam) expected to be affected
by the control. The number of units was estimated as the
total units in the application times the expected fraction
of the application that could undertake the control.
o Costs reported as if the entire application adopted the .
control. In this case the costs were multiplied by the
maximum fraction of the application expected to implement
the control (if the entire application was expected to
implement the control, then no adjustment was required).
Once these adjustments are made, the total annualized costs for the control
are divided by the reduction potential for the control to produce a social
annualized cost per kilogram of use avoided. Detailed examples of social
annualized cost calculations are shown in Exhibits 1-13 through 1-15 for product
substitute, chemical substitute, and add-on engineering control options.
3.4.2 METHODS FOR COMPUTING PRIVATE ANNUALIZED COSTS
For purposes of assessing firms' potential reactions to restrictions on
CFCs, the costs faced by the firms must be estimated. These costs are referred
to as private costs. As discussed in Section 1, private costs will differ from
social costs because of tax effects, differences in discount rates, and possible
differences in the kinds of costs incurred.
To estimate private costs, a discounted cash flow analysis was used. This
cash flow analysis: (1) computes annualized before-tax costs using a before-tax
private discount rate, (2) estimates incremental cash flows incurred by private
entities including the effects of depreciation and taxes on cash flows, and (3)
computes an annual cost as the net of all annualized cash flows.
In general, the methods used to compute private annualized costs follow
those described to compute social annualized costs. The methods used to
estimate private annualized costs are comprised of the following steps:
1. The magnitude and timing of pre-tax costs (i.e., capital and
operating costs) were specified. Assumptions regarding the
timing of the costs and expenses (relative to the initiation
of the control) are:
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1-41
EXHIBIT 1-13
EXAMPLE SOCIAL COST ESTIMATE
FOR A PRODUCT SUBSTITUTE
Control Description: Fiberglass Batts -- Use Fiberglass as an
alternative insulating material
Application Category: Rigid Polyurethane Foam -- Boardstock Building
Construction
Ozone-Depleting Compound: CFC-11
1. Estimated Use Reduction Potential for Application Category
CFC-11/ Market Use Reduction
Use in 1985 Penetration For Application
(Metric Tons) * (Percent) - (Metric Tons)
During Manufacturing 2,700 ' 10 270
During Installation 0 10 0
During Product Use
or Servicing 0 --
Other Use 0
Unaccounted For 0 - - _-_-
TOTAL 2,700 270
2. Estimated Annualized Costs per Metric Ton of Foam Replaced
Annualized
Costs (S)
Capital Cost 0 * 0.062 a/ - 0.00
Annual Operating Cost - 0.00
a/ Represents annualization factor used to spread capital costs. Calculated
as4:
90
0.02/(1-(1/(1+0.02) )) - 0.062.
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1-42
EXHIBIT 1-13 (continued)
EXAMPLE SOCIAL COST ESTIMATE FOR A PRODUCT SUBSTITUTE
Annualized
Costs
%
Salvage of Capital
0 % Salvageable Capital
x $ 0 Capital Cost
x 0.673 b/
x 0.062 c/ - 0.00
Product Substitution Costs
+ $11.820 Price of Fiberglass
Required to Replace One Metric
Ton of Rigid PU Foam
x 1.0 d/
- $11,820
$4,600 Price per Metric
Ton of Rigid PU Foam - $7,220
Present Value Energy Cost
$0 Annual Energy Cost
x 31.42 e/ $ 0
TOTAL ANNUALIZED COST $7,220
20
b/ Present value factor calculated as: 1/(1+0.02) - 0.673
c/ See footnote a/.
d/ Factor that accounts for differences in useful lives of fiberglass and
rigid polyurethane foam in this application. In this case, the lives are the
same, so the factor equals 1.0.
e/ Annuity factor calculated as: (1-1/(1+0.02)5°)/0.02 - 31.42 where 50
years is the estimated useful life of fiberglass board.
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1-43
EXHIBIT 1-13 (continued)
EXAMPLE SOCIAL COST ESTIMATE FOR A PRODUCT SUBSTITUTE
3. Cost Adjustment to Industry-Wide Values
19.100 1985 U.S. Consumption of Rigid PU Foam for Application
(Metric Tons)
X 10Z Estimated Market Penetration for Fiberglass
1,910 Metric Tons of Rigid PU Foam Potentially Replaced
X $ 7,220 Annualized Cost Per Metric Ton of Foam
$13.8 Million
4. Annualized Cost Per Kilogram of CFC Use Reduction
$13.8 Million Adjusted Annualized Costs
270,000 Use Reduction for Application (Kilograms)
Social Annualized cost Per Kilogram •• $51
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1-44
EXHIBIT 1-14
EXAMPLE SOCIAL COST FOR A CHEMICAL SUBSTITUTE
Control Description: FC-123
Application Category: Rigid Polyurethane Foam Boardstock -- Building
Construction
Ozone-Depleting Compound: CFC-11
1. Estimated Use Reduction Potential for Application Category
CFC-11 Market Use Reduction
Use in 1985 Penetration For Application
(Metric Tons) * (Percent) - (Metric Tons)
During Manufacturing 2,700 90 a/ 2,430
During Installation 0 90 a/ 0
During Product Use
or Servicing 0 Ob/ "0
Other Use 0 0 b/ 0
Unaccounted For 0 - - --
TOTAL 2,700 2,430
2. Estimated Annualized Costs per Metric Ton of Foam Replaced
Annualized
Costs (S)
Capital and 92 * 0.062 c/ - 5.70
non-recurring Cost
Annual Operating Cost - 0
a/ Estimated market penetration for new products.
b/ Estimated market penetration for existing products. Not relevant for
foams.
c/ Annualization factor used to spread capital and non-recurring costs.
Calculated as:
20
0.02/(1-(1/(1+0.02) ))-0.062.
Note, in this example all costs are non-recurring reformulation costs, and
no capital costs are expected.
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1-45
EXHIBIT 1-14 (continued)
EXAMPLE SOCIAL COST FOR A CHEMICAL SUBSTITUTE
Annualized
Costs
Salvage of Capital
0 Z Salvageable Capital
x $ 0 Capital Cost
x 0.673 d/
x 0.062 e/ - .0.00
Chemical Substitution Costs
New Existing
Products Products
4.14 NA Price of FC-123
x 1.25 NA Kilograms of FC-123
Blowing Agent Needed to
Replace 1 Kilogram of CFC-11
- 5.18 NA
1.41 NA Price of CFC-11 ($/kg)
3.77 NA Cost of Substituting 1 kg of
CFC-11
x 1.41 f/ NA
531.57 NA
20
d/ Present value factor calculated as: l/(l+0.02) - 0.673
e/ See footnote c/
f/ Estimated number of kilograms of CFC-11 used per metric ton of foam.
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1-46
EXHIBIT 1-14 (continued)
EXAMPLE SOCIAL COST FOR A CHEMICAL SUBSTITUTE
Total Annualized Costs (New Products) 537.27
Total Annualized Costs (Existing Products) NA
3. Cost Adjustment to Industry-Wide Values (New Products Only)
19.100 19.85 U.S. Consumption of Rigid PU Foam for
Application (Metric Tons)
x 902 Market Penetration for FC-123
17,190 Metric Tons of Foam
x $537.27 Annualized Cost Per Metric Ton of Foam
$9.2 million
4. Annualized Cost Per Kilogram of CFC Use Reduction
$9.2 million Adjusted Annualized Costs
2,430,000 Use Reduction for Application (Kilograms)
$3.80 Social Annualized Cost per Kilogram
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EXHIBIT 1-15
EXAMPLE SOCIAL COST ESTIMATE FOR AN ADD-ON
ENGINEERING CONTROL OPTION
Control Description:
Vertical Foam Chamber with Carbon Absorption
and Recovery*
1.
Application Category: Flexible Polyurethane Foam -- Slabstock
Ozone-Depleting Compound: CFC-11
Estimated Use Reduction Potential for Application Category
CFC-11 Estimated
Emissions Market Control
in 1985 Penetration Effectiveness
(Metric Tons) x (Percent) x (Percent)
During Manufacturing 11,500 2
During Installation 0 " 0
During Product Use
or Servicing 0 0
During Product
Disposal
Other Use
Unaccounted For
TOTAL 11,500
2. Estimated Annualized Costs for All Industry
60
0
0
0
0
0
0
. .
0
0
. .
Capital Cost
Non-Recurring Cost
Annual Operating Cost
155.000.000 x 0.062 a/
57.500.OOP x 0.062 a/
Use Reductioi
For Applicatit
(Metric Tons
138
0
0
0
138
Annualized
Costs (S)
9,610,000
3,565,500
21.000.000
*Note: This control is used here to illustrate the method used to estimate
costs. It is not anticipated that this control is likely to be undertaken in
response to regulations on CFCs.
a/ Annualization factor used to spread capital costs. Calculated as:
0.02/(1-(1/(1+0.02)20)) - 0.062.
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EXHIBIT 1-15 (continued)
EXAMPLE SOCIAL COST ESTIMATE FOR AN ADD-ON
ENGINEERING CONTROL OPTION
Annualized
Costs (S)
Salvage of Capital
10 Z Salvageable Capital
x 155.000.000 Capital Cost
x 0.673 b/
x 0.062 c/ - -647,000 d/
Annual Offsetting Savings -8.000.000
TOTAL
25,528,000
3. Cost Adjustment to Industry-Wide Values
$25,528,000 Annualized Costs
x 2Z Market Penetration
$ 510,560
4. Annualized Cost per Kilogram of CFC Use Reduction
$ 510,560 Adjusted Annualized Costs
138,000 Use Reduction for
Application (Kilograms)
Social Annualized cost per kilogram - $3.70
20
b/ Present value factor calculated as: 1/(1+0.02) - 0.673
c/ See footnote a/
d/ Negative cost.
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o capital and non-recurring costs occur in year 0;
o capital salvage occurs at end of the capital's
operating life;
o depreciation expense occurs over seven years;
operating costs and offsetting savings are
incurred during the technical substitute's
operating life.
2. Total pre-tax costs were calculated for each year over the
control's operating life.
3. Taxes were applied to costs incurred after year 0 by
multiplying the costs by (1-tax rate). Annual offsetting
savings were also multiplied by (1-tax rate).
4. Depreciation was "added back" to net after-tax costs to
account for the tax savings attributable to this non-cash
expense.
5. The stream of after-tax cash flows was discounted using
the private cost of capital to compute a net present value
of the costs of the control over its entire life.
6. The present value of the after-tax costs was annualized
using the private cost of capital as the discount rate.
This present value is then divided by the total reduction
in CFC use that can be achieved by the control to produce
an annualized private cost per kilogram of use avoided.
Taxes were calculated using a marginal total tax rate of 44 percent. This
rate includes a federal corporate income rate of 34 percent and an assumed
average state tax rate of 10 percent. Investment Tax Credits (ITCs) were
assumed not to be available. After-tax cash flows arising from capital salvage
were calculated by multiplying pre-tax salvage by (1-tax rate). A tax loss was
included on undepreciated capital whenever the depreciable life exceeded the
operating life of capital.
Annual depreciation expense was calculated, using the straight line method
over seven years. This assumption is conservative because depreciation expenses
occur uniformly over the depreciation period, whereas accelerated depreciation
methods produce tax benefits in earlier years. Because depreciation is based on
initial acquisition costs, annual depreciation expense was deflated by an
inflation index to calculate real depreciation. An inflation rate of 4 percent
was used.
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To select the appropriate rate of private discount, the available literature
was surveyed. ^ As was the case for the social rate of discount (see Appendix
H), little consensus existed among the experts who have studied this problem.
The range of estimated values for the real rate of return on private investments
was from 4 to 9 percent. Accordingly, 6 percent was selected as a median
estimate.
This range of estimates agrees well with the cited range for the rate of
social discount. One would expect the private rate to be from 2 to 5 percentage
points higher than the social rate because of (a) the taxation of private income
and (b) the need for society to subsidize capital formation to provide for
future generations.
The costs of energy losses due to reduced insulating abilities of product
substitutes may not be incurred by firms. Instead, these costs (or a portion of
these costs) may be incurred by consumers if the reduced insulating value of the
product substitutes is not capitalized into their market price. The analysis
assumes that the reduced insulating' value of the substitutes is capitalized into
the price of the substitutes, meaning that consumers are left unaffected, and .
the firms making the substitutes "incur" these costs. The importance of this
baseline assumption may be explored through sensitivity analysis by varying the
portion of these costs incurred by firms, and the portion incurred by
consumers.^
3.5 Construct Derived Demand Schedules for Each Application
Based on estimates of social and private annualized costs and reduction
potentials for control possibilities, two derived demand schedules for CFCs
(social and private) were constructed for each application. The demand
schedules reflect the amounts of reduction that the controls can achieve and the
annualized cost per kilogram of achieving them.
Of particular importance in developing these demand schedules is that the
individual control possibilities be aggregated in a proper manner, so that
compatible controls are adopted over time. To specify the set of compatible
23 Studies surveyed included Jacob Stockfish, "The Interest Rate Applicable
to Government Investment Projects," in Program. Budgeting and Benefit Cost
Analysis. Hinrichs and Taylor (eds.); Daniel Holland and Stewart Myers,
"Profitability and Capital Costs for Manufacturing Corporations and All
Nonfinancial Corporations," American Economic Review. May 1980; Barbara Fraumeni
and Dale Jorgenson, "Rates of Return by Industrial Sector in the United States,
1948-1976," American Economic Review. May 1980; William Brainard, John Shoven
and Laurence Weiss, "The Financial Valuation of the Return to Capital,"
Brookings Papers on Economic Activity. 1980; Robert Lind, "A Primer on the Major
Issues Relating to the Discount Rate for Evaluating National Energy Options," in
Discounting for Time and Risk in Energy Policy. Resources for the Future, 1982.
^ This issue does not arise in the computation of social costs because the
distribution of the costs (i.e., between manufacturers and consumers) is not consid
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controls, the full list of control possibilities for each application was
examined, and a subset of likely controls was identified. This subset is
referred to as a control plan.
The choice of options to include in the control plan is uncertain and
somewhat subjective. The key factors considered in developing the control plans
were: technical feasibility and expected availability; cost; potential impacts
on product quality; and internal consistency both within each year (i.e.,
substitutes may be mutually exclusive) and across time (i.e., firms may decide
not to undertake controls available today in anticipation of other, preferred
controls becoming available later). For example:
o although several potential chemical substitutes may be
feasible, only one chemical substitute is likely to be
used, particularly if different process modifications are
required to use each of the substitutes;
o some controls are likely to be used in tandem, requiring
the analysis to ensure equal adoptions of each; and
o two (or more) controls may be mutually exclusive, meaning
that only one is likely to be undertaken.
In general, the development of the control plan reduced the menu of likely
controls from the total of about 550, to about 350. The number of control
possibilities per application generally ranges from about three to ten. These
three to ten control possibilities were used to construct the derived demand
schedule for each of the applications.
The control possibilities in the control plan for each application were then
ordered from least to most costly based on the private annualized cost,
representing the assumption that the available least costly controls would be
undertaken first. Then the use reduction potential over time for each of the
controls was modified to reflect the impacts of the controls being taken in a
group. (The use reduction estimates described above in section 3.3 were
estimated based on the assumption that the controls were taken individually).
F.or controls that are independent, the. least expensive control was assumed
to achieve its full use reduction potential. More costly controls are modeled
to result in less reductions, because the cheaper controls have already reduced
the total use in the application. In general, the more expensive controls are
assumed to apply only to the portion of the application not affected by the
cheaper controls. ^
Because the various controls are estimated to become available over time,
and because each control requires time to penetrate the market and become
implemented, the potential reductions that can be achieved increase over time.
" Several exceptions to this procedure were implemented in cases where the
control plans specified that the separate controls applied to different segments
of the application in a manner that results in the full reduction potential of
each being achievable.
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Based on these estimates, the private and social derived demand schedules
for each application can be drawn. The private derived demand schedule is drawn
first because the private costs determine the order of the controls in the
curve. As shown in Exhibit 1-16, the horizontal steps in the demand schedule
represent the reduction in annual CFG use associated with the controls. The
vertical steps are the annualized costs per kilogram of undertaking the
controls. The private derived demand schedule slopes downward because the
controls are ordered from least to most costly.
Also shown in Exhibit 1-16 is the fact that the derived demand schedule
shifts over time. As additional controls become available and may be
implemented, the level of reduction that can be achieved increases. Therefore,
the curve appears to shift downward over time.
Exhibit 1-17 displays a social derived demand schedule. The format for the
curve is the same, but it need not be downward sloped because the order of the
controls is defined by the private costs.
3.6 Aggregate Derived Demand for CFCs
The social and private aggregate derived demand schedules for all the CFCs
being controlled as a group were estimated by: (1) summing the derived demand
schedules from all the applications within each compound to create aggregate
compound derived demand schedules; and (2) aggregating across compounds by
scaling according to the ozone depletion potential of each. The results are
social and private aggregate derived demand schedules that relate total demand
for all the ozone depleting compounds to their price (expressed in ozone
depleting potential units as well).
These aggregate derived demand schedules are analogous to the individual
application schedules and have the same general shape. The primary difference
is that the aggregate schedule is expressed in terms of ozone depleting
potential, and there are many more steps.
3.7 Estimate Social and Private Costs
The social and private costs of restricting the use of CFCs is estimated by
identifying the appropriate area under the derived demand schedule as described
in Section 1. For each year of the analysis, the appropriate aggregate derived
demand curve is first identified. Then the level of reduction required by the
policy in that year is identified. The level of reduction is equal to the
percentage change from the baseline level of CFC use (that would occur, in the
absence of the controls) that is required. Because the level of CFC use is
generally expected to increase in the absence of regulatory requirements, even a
freeze in the amount of allowable CFC use at, say, 1986 levels will require a
reduction in use over time. Because baseline CFC use is expected to grow, the
required amount of reduction will also grow.
The level of reduction required is used to identify which controls in the
aggregate derived demand schedule must be undertaken. For example, Exhibit 1-18
displays the requirements of a 20 percent reduction. All the controls that fall
to the right of the line marked "quota" are simulated to be needed to reach the
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EXHIBIT 1-16
EXAMPLE OF A PRIVATE DERIVED DEMAND SCHEDULE
CFC
Price
1
I
I
Private
Derived Demand
Schedule for Tn
Private
Derived Demand
Schedule for Tt
I -.
100%
0%
Percent
Reduction
Achieved
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EXHIBIT 1-17
EXAMPLE OF A SOCIAL DERIVED DEMAND SCHEDULE
Social
Costs
Per
Kilogram
Social
Derived Demand
Schedule for Tn
Social
Derived Demand
Schedule for T.
100%
Percent
Reduction
Achieved
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desired 20 percent reduction. These controls may fall in any number of
applications, and some applications may be simulated to undertake no controls at
all (at this level of reduction).
As shown in the exhibit, the quota may fall in the middle of a horizontal
step. For purposes of analysis, it is assumed that the entire control
represented by that step will be undertaken. In this case, the actual reduction
achieved will exceed the desired reduction. The "over reduction" is expected to
be small, however, because the reductions achievable with individual controls
are small relative to the total use of the compounds.
The area labeled C in Exhibit 1-18 is used to estimate the private cost of
achieving the 20 percent reduction (an analogous area exists on the social
derived demand schedule for purposes of estimating social costs). An
analogous calculation is made using the social derived demand curve for purposes
of estimating the total social costs.
Exhibit 1-18 also identifies the transfer payments made by firms as the
result of the restriction in CFG production. The increased cost per kilogram
that results is given by P(l), the simulated resulting price, minus P(0), the
original price. This cost is equal to the incremental cost of the most costly
control simulated to be taken in that year. This value times the remaining CFG
use (in this example, 80 percent of the baseline use) gives the estimate of the
transfer payments.*'
The implications for each application can also be evaluated by breaking the
aggregate derived demand curve back into its individual components. The costs
of the controls that are simulated to be taken within each application can be
estimated, along with the level of reduction achieved and the transfer payment.
To compute the transfer payment for an application, the most costly control
simulated to be taken in the aggregate derived demand schedule is used, and not
the most costly control simulated in the application derived demand schedule.
As noted above, the level of reduction may vary across the applications.
By breaking the aggregate derived demand curve into its individual
components, the level of chemical substitute use can also be estimated. This
level is of interest because it depends upon the simulated availability of
potentially new compounds that are currently under development.
This method of analyzing a reduction in use can also be applied to the
evaluation of a fee or a command and control policy. The fee is evaluated by
identifying the intersection of the fee level with the derived demand curve. In
Exhibit 1-18 the fee level would be equal to P(l) minus P(0), and the cost of
the reductions associated with the fee would be the same as the cost of the
quota.
Note that the calculation is made on an aggregate basis. The cost of
the reduction is multiplied by the number of kilograms reduced. This method
assumes implicitly that the mix of uses in the baseline remains unchanged.
2' Transfer payments are only estimated using the private derived demand
schedule. The transfers are not considered to be social costs.
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EXHIBIT 1-18
EXAMPLE OF A PRIVATE COST ESTIMATE USING THE
PRIVATE DERIVED DEMAND CURVE
Price
Per
Kg Weighted
For Ozone-
Depleting
Potential
Quota
100*
20% Q% Percent
Reduction
Achieved
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To evaluate a command and control option, the controls required are arranged
into a derived demand schedule, and the area beneath it is used to estimate
.social and private costs. Because the controls are not simulated to be
undertaken in response to increased prices for CFCs, there is no transfer
payment in the command and control evaluation.
4. LIMITATIONS
The methods used to assess the social private costs of proposed restrictions
on CFC use are limited in terms of the data available and the manner in which
the method is applied. The primary limitations of the data include:
o Identification of Control Possibilities. By definition
only those control possibilities that are currently known
are included in the analysis. It is likely that as the
prices of CFCs rise in response to the constriction of
supply that additional control possibilities will be
identified. The inability to incorporate unknown control
possibilities biases the estimates of costs upward,
although the extent of the bias is not known.
.0 Aggregation of Control Possibilities. The aggregation of
the control possibilities to reflect the impacts of taking
groups of controls is subjective. Alternative views of
aggregation could lead to alternative estimates of control
costs and achievable reductions.
o Uncertainty Surroundine New Chemical Substitutes. Many of
the data estimates are very uncertain, and consequently
ranges of values are used, and sensitivity analysis is
performed. Nevertheless, the uncertainty surrounding the
data describing the new chemical substitutes has a large
influence on the cost estimates produced. The areas of
uncertainty primarily include the timing of availability
of the new chemical substitutes (which has a large
influence on the level of reductions that can be
achieved), the cost of the new 'chemical substitutes, and
the extent to which the new chemical substitutes can be
used in existing products.
o Unallocated Use. A significant portion of current CFC use
cannot be allocated to specific applications. Therefore,
there are no specific methods identified for controlling
these uses. The analysis addresses this problem by
assuming that the costs of controlling this unallocated
use are similar to the costs of controlling the allocated
use. As a sensitivity, the unallocated use may be assumed
to be uncontrollable. Because the unallocated use must be
controllable at some cost, the sensitivity analysis must
be biased upward. The potential bias of the base
assumption is not known, although the fact that the use is
not easily identifiable may imply that it is more
difficult to control than the identified use. If this is
the case, then the base assumption is biased downward.
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Another set of limitations of the method used relates primarily to the
aggregate manner in which the control data are applied. The aggregate derived
demand curve indicates the levels of reductions that can be achieved at various
levels of costs. The costs are expressed on a per kilogram basis, and are
estimated based on 1985 values. The method implicitly assumes that the controls
are divisible (i.e., there are no major economies of scale) and that they can be
phased in over time. Further, because the estimates are based on 1985 data, the
potential changing mix of uses (in the absence of controls) is not reflected.
Because the implementation of individual pieces of equipment are not tracked
over time, the implications of this 'aggregate approach cannot be assessed.
The method also assumes that the primary mechanism driving the allocation of
CFCs across competing uses is price. Although this is a standard assumption for
analyses of this type, other factors (such as the relationship between producers
and their customers) may influence the allocation of CFCs. To the extent that
CFCs are not allocated based on price, the estimates of costs will be biased
downward. A related assumption is that manufacturers implement the least costly
control options. If more costly controls are undertaken, the cost estimates are
also biased downward. The implications of the least costly controls not being
taken is evaluated by "omitting" sets of inexpensive controls from the menu of
control possibilities. (See Chapter 9 of Volume I.)
Two types of costs not considered are transition costs and risks.
Transition costs (e.g., temporary unemployment or premature retirement of
capital equipment) are generally small over the long-term, but' may be important
when reductions are initially required. Because significant phase-in times are
contemplated, transition costs are likely to be small. Also many of the control
options ar' compatible with existing equipment (thereby avoiding the premature
retirement of capital).
The additional risks posed by the control options have not been evaluated.
Numerous options were deleted from consideration due to risks, so
that the options used in the analysis may not result in significant risks.
However, some examples of risks are evident, and additional analysis to assess
these risks may be warranted. °
A key assumption is that the demand for the services provided by the
CFC-related products is sufficiently inelastic and the portion of the products'
costs accounted for by CFCs is sufficiently small that the reductions in end
u'seproduct demand that result from increased prices of CFCs can be ignored.
This is probably a reasonable assumption in most cases. The implications of the
assumption are that more controls are simulated to be taken than would otherwise
be the case, and social costs are biased upward.
Finally, the analysis assumes that the CFC supply curve is horizontal and
CFC prices equal their marginal costs. This assumption results in no estimates
of lost producer surplus in the CFC market. If the price of CFCs exceeds
marginal cost, and if the supply curve 'for CFCs is not horizontal in the
relevant range, then the social cost estimates are biased downward.
2° For example, pentane is listed as an alternative blowing agent.
Although the costs of equipment to address its potential fire hazard are
included in the cost estimates, the potential impact of pentane emissions on
smog conditions has not been evaluated, except as it adds costs to that option.
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KEY SOURCES
Primary sources relied upon in this document include:
U.S. Environmental Protection Agency (U.S. EPA) (1987), Assessing the
Risks of Trace Gases that can Modify the Stratosphere. U.S. EPA,
Washington, D.C.
U.S. Environmental Protection Agency (U.S. EPA) (1987), Regulatory Impact
Analysis: Protection of Stratospheric Ozone. U.S. EPA, Washington, D.C.
World Meteorological Organization (WHO) (1986), Atmospheric Ozone 1985:
Assessment of our Understanding of the Processes Controlling its
Distribution and Change. WHO Report No. 16, WHO, Geneva, Switzerland.
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LIST OF PREPARERS AND REVIEWERS
This EIS was prepared and reviewed by the following individuals:
Name Organization
Stephen Seidel Office of Air and Radiation/EPA
Judy Troast Office of Federal Activities/EPA
Nancy Ketcham-Colwill Office of General Counsel/EPA
Jamison Koehler Office of International Activities/EPA
Suzanne Butcher Office of Oceans, Environment and
Science/State Department
Debra Kennedy Legal Advisors Office/State Department
Consultants:
Michael Gibbs ICF Incorporated
Mark Handwerger ICF Incorporated
Kevin Hearle ICF Incorporated
Brian Hicks ICF Incorporated
William McNaught ICF Incorporated
John Wells The Bruce Company
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