EPA 910-R-11-003 I May 2011 I www.epa.gov
Reducing Greenhouse Gas
Emissions through Recycling
and Composting
A Report by the Materials Management Workgroup
of the West Coast Climate and Materials
Management Forum
May 2011
United States Environmental Protection Agency, Region 10
Seattle, WA
-------
Acknowledgements
This report was prepared on behalf of the U.S. EPA Region 10 and the West Coast Climate and
Materials Management Forum by the Forum's Materials Management & Product Stewardship
Workgroup. Special thanks to all of the EPA staff and Forum members who reviewed drafts, offered
revisions, and contributed to the final product. Specifically, we acknowledge the contributions of
workgroup leaders Bill Smith of the City of Tacoma Solid Waste Management Division and John
Davis of the Mojave Desert and Mountain Recycling Authority, as well as EPA NNEMS Fellows
McKenna Morrigan and Evan Johnson. Questions about the report may be directed to Ashley Zanolli,
Environmental Engineer, U.S. EPA Region 10. To learn more about the West Coast Climate and
Materials Management Forum, visit http://www.epa.gov/regionio/westcoastclimate.htm
Table of Contents
Introduction 2
Section i. Objectives and Rationale for Our Project 4
Section 2. Research Design and Methodology 5
Section 3. Using WARM to Identify Priority Materials for Emissions Reduction 7
Section 4. Implications for Emissions Reductions and Carbon Offsets 10
Section 5. Additional Benefits of Recycling and Composting Priority Materials 12
Section 6. Opportunities for Reducing Emissions through Recycling and Composting 14
Section 7. Summary Reflections and Next Steps 20
APPENDIX A: State Waste Tonnage Data by WARM Category 22
APPENDIX B: WARM Per Ton Emissions Estimates for Alternative Management Scenarios 24
APPENDIX C: Concerns with WARM Emissions Factor for Carpet Recycling 25
APPENDIX D: Proportions of Waste from Commercial and Residential Substreams 26
APPENDIX E: Benefits and Limitations of WARM Model 27
List of Figures and Tables
Figure i Sector-based accounting of U.S. GHG Emissions 4
Figure 2 Systems-based accounting of US GH G Emissions 4
Table i: Materials with Highest Potential for GHG Emissions Reduction, by State 8
Figure 3: Net Annual Emissions Reduction Potential of Recycling and Composting 9
Table 2: Emissions Reduction Goals Relative to Potentials of Recycling and Composting 11
Table 3: Additional Revenue Potential from Recycling and Composting 13
-------
Introduction
"Materials management is an approach to serving human
needs by using and reusing resources most productively and
sustainably throughout their life cycles, minimizing the
amount of materials involved and all the associated
environmental impacts."
- Definition adapted from "Sustainable Materials
Management: The Road Ahead" (U.S. EPA 2009)
The West Coast Climate and Materials Management Forum, an EPA-led partnership of western local,
state, and tribal governments, established a Materials Management & Product Stewardship
Workgroup to identify key materials management strategies that could be used by local governments
to reduce greenhouse gas (GHG) emissions in the near term.
The workgroup began by focusing on the life-cycle impacts of materials currently being disposed in
landfills and the GHG emissions reductions that are possible by diverting discarded materials from
landfills through recycling and composting. Although additional materials management approaches,
including reuse, remanufacturing, source reduction, material reduction/substitution,
environmentally preferable purchasing, upstream design and manufacturing changes, also promise
significant emissions reductions, the scope of this paper is limited to evaluating only recycling and
composting. Future Workgroup projects will focus more on the emissions reduction potential of these
other approaches.
Purpose of the Report
This report is intended to help governments and other organizations make informed and strategic
decisions about how to direct their limited resources toward end-of-life management of materials
that provides the most significant impact on life-cycle greenhouse gas emissions. The report also
provides rationale, from a climate action, economic and pollution prevention perspective, for local
jurisdictions to adopt and implement recycling and composting initiatives in their communities.
We hope this report continues to build a unified intellectual foundation from which to consider
climate change in a materials management context. We also hope it opens opportunities for strategic
regional cooperation to improve materials management approaches to reduce emissions attributable
to goods and food throughout their life cycle.
Report Summary
The analysis uses the U.S. EPA's Waste Reduction Model (WARM) Calculator to estimate the GHG
emissions attributable to materials in the waste streams of California, Oregon, and Washington, and
to identify the materials with the greatest emissions reduction potential if recycled or composted
rather than landfilled.
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
This report draws on the WARM results to highlight ten materials, broken into four priority material
types with the greatest emissions reduction potential (presented alphabetically):
• Carpet
• Core Recyclables
• Corrugated containers
• Office paper
• Aluminum cans
• Newspaper
• Magazines
• PET and HDPE (or mixed plastics)
• Steel cans
• Dimensional Lumber
• Food Scraps
Section l of this report outlines the objective and rationale for our analysis.
Section 2 describes the research design and methodology used, including a brief introduction to the
WARM Calculator and how it can be used.
Section 3 presents the findings of our analysis for each state and across the three states.
Section 4 discusses the implications of our analysis and describes how the results relate to local and
state policy goals for emissions reductions.
Section 5 highlights additional benefits of recycling and composting these priority materials,
including job creation, economic development, and reduced land and marine pollution.
Section 6 briefly describes opportunities for reducing emissions through recycling/composting of
our four priority material types.
Section 7 provides summary reflections and concludes with comments about how the Materials
Management workgroup will explore ways to further reduce life-cycle emissions of materials through
research on additional sustainable materials management practices.
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
Section 1. Objectives and Rationale for Our Project
Traditional, sector-based accounting of GHG emissions obscures the importance of materials
management in addressing global climate change. Figure i depicts a typical accounting of GHG
emissions, attributing the majority of impacts to the industrial, transportation, and electric power
sectors.1 In this accounting, methane emissions generated by landfills (included under the
Commercial sector) account for 1.8% of total U.S. GHG emissions. While the sector-based approach is
useful for highlighting opportunities for end-of-pipe emissions reduction strategies, this accounting
fails to illustrate the emissions associated with the life cycles of materials and land management
practices.
In a September 2009 report, Opportunities to Reduce Greenhouse Gas Emissions through Materials
and Land Management Practices, the U.S. EPA employed a systems-based accounting method to
categorize U.S. GHG emissions. Figure 2 depicts the EPA's approach.2 The systems-based accounting
reveals that 42% of emissions result from materials management, i.e. the extraction of natural
resources, and production, transport and disposal of food and goods.3
Figure 1
Sector-based accounting of U.S. GHG Emissions
Figure 2
Systems-based accounting of US GHG Emissions
Residential
Commercial 5%
Agriculture
Industry
19%
Electric Power
Industry
34%
Materials
Management
42%
Transportation
28%
Local
Passenger
Transport
15%
Other
Passenger
Transport
Building HVAC
and Lighting
25%
Expanding the scope of the EPA's report, the Product Policy Institute took EPA's National Emissions
Inventory (NEI), subtracted out the emissions associated with exports and added in emissions
associated with imports to the US. This provides a more accurate view of the emissions associated
with goods used in the US. Under this global view of emissions associated with the US economy,
overall GHG emissions are 12% higher than domestic emissions, and 44% of the total are associated
with the production, transport, and end-of-life management of non-food materials alone.4
1 U.S. Inventory of GHG Emissions and Sinks: 1990-2006 (US EPA, 2008).
2 Opportunities to Reduce GHG Emissions through Materials and Land Management Practices (US EPA, 2009).
3 This percentage only accounts for emissions associated with domestic production. The figure would be much larger if it also
measured emissions from the international production of goods that are consumed in the U.S.
Joshua Stolaroff, Products, Packaging, and US Greenhouse Gas Emissions (Product Policy Institute, 2009).
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
Current trends in production, consumption, and waste management have led to enormous emissions
of heat-trapping greenhouse gases. The sources of such emissions are numerous, ranging from
carbon dioxide released during the extraction and production of new materials to methane from the
decomposition of organic waste in landfills.
Although the direct GHG emissions reductions achieved by landfill diversion are limited, the
potential upstream impacts are much higher, if the end-of-life strategies used are able to reduce
future emissions generated through the provision of goods and food. For example, diversion of
aluminum from landfills for recycling offers minimal reductions in landfill emissions, but the use of
recycled aluminum reduces emissions by reusing the material. The energy input of producing a ton of
aluminum, which is directly linked to emissions output, is 96% lower when recycled aluminum is
used. This is due to the elimination of the mining and smelting process required for virgin
aluminum. Thus, end-of-life materials management strategies such as recycling can lead to
significantly lower emissions from early stages in the material life cycle, including material
extraction, manufacturing, and distribution.
This report seeks to quantify those potential life-cycle emissions reductions that could be achieved by
recycling or composting waste currently being landfilled in California, Oregon, and Washington. By
identifying the materials with the greatest emissions reduction potential, the analysis reveals that
some of these emission reductions can be achieved in the short term through existing recycling
infrastructure, while others will require new infrastructure and programs to divert these priority
materials from disposal.
Section 2. Research Design and Methodology
Our analysis uses recent, state-level waste characterization data from California, Oregon, and
Washington. 7, it is important to note that the this analysis uses data on the amount of materials
currently being disposed of and does not analyze the emissions reductions of materials already being
diverted from disposal. While it is possible to estimate the emissions reductions from existing
recycling and composting programs, the goal of this report is to identify the additional emissions
reduction potential possible through recycling and composting materials still being discarded as
waste, so only data on materials currently disposed are included. To identify the top ten materials by
emissions reduction potential based on quantity of material available for recovery, we used the Waste
Reduction Model (WARM) created by the U.S. Environmental Protection Agency (EPA).
The EPA created WARM to help solid waste planners and organizations estimate greenhouse gas
(GHG) emission reductions from several different waste management practices. WARM is available
as a Web-based calculator format and as a Microsoft Excel© spreadsheet. Both versions of WARM
are available on the EPA's Web site.9
WARM calculates GHG emissions based on a comparison of a baseline and alternative waste
Tellus Institute Packaging Study (Tellus Institute, 1992).
6 California 2008Statewide Waste Characterization Study (Cascadia Consulting Group for CIWMB, 2009).
2009/2010 Waste Composition Study: Preliminary (Oregon Department of Environmental Quality, 2010).
8 2009 Washington Statewide Waste Characterization Study (Cascadia Consulting Group for WA Department of Ecology, 2010).
http://www.epa.gov/WARM
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
management practice, including source reduction, recycling, combustion, composting, and
landfilling. The model calculates emissions in metric tons of carbon equivalent (MTCE) or metric
tons of carbon dioxide equivalent (MTCO2E) across a wide range of material types commonly found
in municipal solid waste (MSW). WARM users can construct various scenarios by simply entering
data on the amount of waste handled by material type and by management practice. WARM then
automatically applies material-specific emission factors for each management practice to calculate
the GHG emissions and energy use of each scenario.
Several key inputs, such as landfill gas recovery practices and transportation distances to MSW
facilities, can be modified by the user. For this analysis, estimated tons of materials disposed, drawn
from each state's waste characterization study, were entered into the WARM Calculator. The WARM
Calculator quantified the GHG emissions reductions comparing two waste management scenarios: i)
all of the materials are deposited in landfills; and 2) all of the materials are instead recycled or
composted. Although a small amount of waste disposed of in California, Oregon and Washington is
incinerated, the large majority is disposed of in landfills, making this a reasonable, simplifying
assumption.
The emissions reduction potential of recycling or composting the materials disposed of in each state
was then ranked from highest to lowest and results from all three states were then compared.
The resulting list of priority materials includes the top ten materials from each state's list. For all
other WARM inputs, the default settings were used. This includes whether Landfill Gas (LFG) control
systems are in place, what percentage of methane is captured, whether collected methane is flared or
recovered for energy, and the assumed moisture conditions and associated bulk decay rate of
disposed waste, (all of which affect the rate of methane emissions from landfills), as well as the
assumed transport distances for landfilling, recycling, and composting, which affect the emissions
associated with these various end-of-life management options.10'11
Several difficulties persist for the accurate comparison of state waste measurements. First, waste
policies differ across states and localities, leading to differences in the types of materials collected.
Second, how waste characterization studies define material categories and gather data varies across
states. For instance, California and Washington specify plastic by polymer type (i.e. PET, HDPE,
etc.), while Oregon specifies it by container type (i.e. bottle, tub) and by whether it is accepted in
curbside recycling programs. Both Oregon and Washington specify 15 different types of paper, broken
into "packaging" and "non-packaging" subcategories, while California lumps these together and
includes fewer categories altogether. Even the 15 paper types differ somewhat between Oregon and
Washington, frustrating comparisons. Third, the categories and definitions included in the WARM
Calculator do not always correspond with state waste characterization studies. WARM users face the
challenge of reconciling their materials category definitions with those the model employs. Our
reconciling of categories for this analysis is presented in Appendix A.
10 The WARM Calculator allows users to customize a number of settings that affect the emissions associated with end-of-life
management options. These include whether Landfill Gas (LFG) control systems are in place, what percentage of methane is
captured, whether collected methane is flared or recovered for energy, the assumed moisture conditions and associated bulk
decay rate of disposed waste, and the assumed transport distances for the various end-of-life management scenarios. The default
scenario (which is what we used) calculates emissions based on the estimated proportions of landfills with LFG control in 2008.
Transportation distances only affect the model if the transportation required for the alternative scenario is significantly
different from the baseline scenario (e.g. recycling means sending materials to a nearby MRF, while landfill disposal requires
trucking waste to a landfill hundreds of miles away). However, it is worth noting that most emissions impacts of materials are
upstream, and the transportation emissions related to any end-of-life management approach are minimal in comparison.
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
These discrepancies make it challenging to estimate the emissions reduction opportunities across state
and local governments. Nevertheless, we believe that comparing WARM results for California, Oregon,
and Washington illustrates the opportunity for a common set of strategies for GHG emissions reduction
through recycling and composting in various government arenas. The WARM results, which showed
remarkable similarity across the states in terms of materials, appear to support this belief.
Section 3. Using WARM to Identify Priority Materials
The following section presents the WARM results for each of the three states featured in this report.
Despite incongruities between state measures and WARM features, as well as differences between the
states themselves, commonalities of top materials with emissions reduction potential among the
states are unambiguous. Table i identifies the top ten materials with the highest emissions reduction
potential for each state. Each state's WARM output is displayed graphically in Figure 3, which show
the emissions reduction benefits of recycling the listed materials (or composting, in the case of food
scraps), calculated against a baseline emissions scenario in which they are landfilled.
The WARM results suggest that the greatest potential for emissions reduction across all three states
can be achieved through better end-of-life management of ten materials, broken into four priority
material types:
• Carpet
• Core Recyclables
• Corrugated containers
• Office paper
• Aluminum cans
• Newspaper
• Magazines
• PET and HDPE (or mixed plastics)
• Steel cans
• Dimensional Lumber
• Food Scraps
Carpet12, dimensional lumber, and food scraps appear in the top ten for all three states. Six of the
seven materials comprising core recyclables also appear on all three lists. Of note among the core
recyclables is corrugated containers, or cardboard, which alone constitutes half of the total potential
of all core recyclables in California and Oregon and roughly one third of emissions reduction
potential of core recyclables in Washington.
There are two factors that determine which materials rank highest in terms of emissions reduction
potential: first, the GHG emissions reduction potential of recycling or composting each material on a
per ton basis according to WARM; second, the overall tonnage of each material that is disposed,
" The waste characterization data used in this analysis provide estimated tonnage for all carpet disposed in each state.
However, our emissions factors are for carpet made with nylon fibers only, resulting in some difference in the emissions
reduction potential reported here and the actual emissions reduction potential in each state, depending on what proportion
of disposed carpet is made with non-nylon fiber. In its 2009 Annual Report, the Carpet America Recovery Effort estimates
that 76% of carpet material recycled nationally in 2009 was nylon (49% N6, 27% N66).
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
relative to the tonnage of other materials disposed in the state. Most of the materials listed above
rank high in GHG emissions reduction potential on a per ton basis, even though they make up a
relatively small proportion of total waste disposed.
Food scraps are the exception, in that WARM does not assign them a particularly high emissions
reduction potential per ton, but they nonetheless appear in the top ten because they make up a
significant portion of disposed waste. The per ton emissions factors used in the WARM calculations
are listed in Appendix B.
Table 1: Materials with Highest Potential for GHG Emissions Reduction, by State
CALIFORNIA
Material Type
Carpet
(WARM)13
Carpet
(Sound Resource
Management)
Core
Recyclables
Aluminum Cans
Corrugated
Containers
Magazines
Newspaper
Office Paper
PET
Steel Cans
Dimensional
Lumber
Food Scraps
Est. Tons
1,285,473
1,285,473
3,904,101
47,829
1,905,897
283,069
499,960
731,298
199,643
236,405
1,184,375
6,158,120
MTCO2e
Reduction
Potential
9,324,721
2,892,314
12,217,563
652,958
6,061,274
750,902
913,943
3,093,923
310,425
434,140
2,123,138
5,837,189
OREGON
Material Type
Carpet
(WARM)
Carpet
(Sound Resource
Management)
Core
Recyclables
Aluminum Cans
Corrugated
Containers
Magazines
Newspaper
Mixed Plastics
Office Paper
Steel Cans
Dimensional
Lumber
Food Scraps
Est.
Tons
67,610
67,610
180,860
2,937
75,266
15,030
18,640
28,035
22,794
18,158
71,555
457,709
MTCO2e
Reduction
Potential
490,438
152,123
526,229
40,096
239,367
39,870
34,074
43,041
96,435
33,346
128,271
433,855
WASHINGTON
Material Type
Carpet
(WARM)
Carpet
(Sound Resource
Management)
Core
Recyclables
Aluminum Cans
Corrugated
Containers
Magazines
Newspaper
Office Paper
PET
HOPE
Dimensional
Lumber
Food Scraps
Est.
Tons
145,282
145,282
495,334
28,085
189,205
46,149
82,682
49,667
48,079
51,467
51,929
920,676
MTCO2e
Reduction
Potential
1,053,864
326,885
1,616,408
383,414
601,724
122,420
151,145
210,128
74,758
72,819
93,089
872,695
The first estimate of emissions reduction potential for carpet is based on the WARM Calculator factor for open loop recycling
of carpet (into carpet pad, molded plastic parts, and carpet tile backing). Because of concerns raised by several members of
the Forum about the assumptions on which the emissions factor is based, we also include an estimate of emissions reduction
potential for closed loop recycling from Sound Resource Management. For a detailed explanation of the concerns with the
WARM factor, see Appendix C.
The second estimate of emissions reduction potential for carpet is based on the emissions factor for recycling carpet into
carpet (closed loop recycling) developed by Dr. Jeffrey Morris of Sound Resource Management in a report for Seattle Public
Utilities titled, "Environmental Impacts from Carpet Discards Management Methods: Preliminary Results." April 26, 2010.
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
Figure 3: Net Annual Emissions Reduction Potential of Recycling and Composting
-9,324,7221
California 2008 MTCO2e Reduction Potential
-6,061,275 I
-5,837,189
-3,093,923 I
-2,892,314
-2,123,138
-913,942 •
-750,902 •
-652,958 •
-434,140
-310,425 •
-10,000,000 -8,000,000 -6,000,000 -4,000,000 -2,000,000 0
Carpet (WARM)
Corrugated Containers
Food Scraps
Office Paper
Carpet (Sound Resource Management)
Dimensional Lumber
Newspaper
Magazines/Third-class mail
Aluminum Cans
Steel Cans
PET
Oregon 2009 MTCO2e Reduction Potential
-490,438 •
-433,855
-239,367
-152,123
-128,271
-96,435
-43,041 I
-40,096 I
-39,870
-34,074
-33,346
-600,000 -500,000 -400,000 -300,000 -200,000 -100,000 0
Carpet (WARM)
Food Scraps
Corrugated Containers
Carpet (Sound Resource Management)
Dimensional Lumber
Office Paper
Mixed Plastics
Aluminum Cans
Magazines/third-class mail
Newspaper
Steel Cans
Washington 2009 MTCO2e Reduction Potential
-1,294,774
-872,695
-601,724
-383,414 •
-326,885
-210,128
-151,145 "
-122,420 •
-93,089 I
-74,758
-72,819
-1,500,000 -1,200,000 -900,000 -600,000 -300,000
Carpet (WARM)
Food Scraps
Corrugated Containers
Aluminum Cans
Carpet (Sound Resource Management)
Office Paper
Newspaper
Magazines/third-class mail
Dimensional Lumber
PET
HOPE
Reducing Greenhouse Gas Emissions through Recycling and Composting
-------
Section 4. Implications for Emissions Reductions and Carbon Offsets
All three West Coast states have set goals for reducing greenhouse gas emissions. Our analysis shows
that recycling and composting can produce significant emissions reductions, and are thus compelling
tools to include in climate plans. It is worth recognizing that some of the life-cycle emissions for
waste disposed in California, Oregon, and Washington that are calculated using WARM are not
generated exclusively (or even predominantly) in these states. Emissions from resource extraction,
manufacturing and transportation associated with materials used and discarded here sometimes
occur outside of the region and would not be captured by most current state GHG inventory methods.
To account for boundary issues, alternate methods for conducting inventories are being developed in
several jurisdictions, including the State of Oregon and King County (WA), which are developing
consumption-based inventories that account for emissions generated outside their boundaries as a
result of consumption within their boundaries. The Inventory Workgroup of the West Coast Climate
and Materials Management Forum has developed a toolkit for other jurisdictions interested in
including consumption-based methods into emissions inventories.15
Even in jurisdictions that have not yet adopted consumption-based inventory methods, some GHG
emissions associated with materials management, such as from long-distance trucks delivering goods
and hauling solid waste out of state, are undoubtedly generated within these states and are included
in existing state GHG emissions inventories. In these cases, reductions in these emissions due to
recycling and composting would be captured by the states' inventories and contribute toward
emissions reduction goals. In addition, methane emissions reductions due to diversion of food scraps
would likely be captured, as these emissions are often counted in conventional inventories.
Emissions Reduction
Diversion of food scraps from landfills offers the greatest quantity of in-state GHG emissions
reductions. Food scraps are responsible for a large share of methane emissions generated by landfills,
and while landfill emissions comprise only a small portion of life-cycle emissions attributable to
goods and food, they nonetheless represent a real opportunity for emissions reduction. This is largely
due to the large quantities of food that is wasted and sent to landfills.
According to our analysis, the emissions reduction potential of diverting one year's worth of food
scraps from landfills through composting is equal to approximately 1.5% of California's 2050
emissions reduction goal, 0.8% of Oregon's goal, and 1.8% of Washington's goal. Note that these are
not one-to-one comparisons—the 2050 emissions reduction goals are the emissions that must be
reduced on an annual basis, while the emissions reductions quantified by the WARM Calculator are
life-cycle emissions that occur over many years based on a single year's food waste—but are simply
16
intended to provide a sense of scale.
For more information about this, visit http://captoolkit.wikispaces.com/
While the emissions reduction in 2050 from composting food waste in 2050 would be much smaller than the numbers shown
in Table 4.1, emissions reductions in 2050 would also include emissions reductions resulting from food waste composting in
2049, 2048, 2047, and previous years. The sooner putrescible wastes are diverted from landfills, the sooner emissions
reductions can begin accumulating.
Reducing Greenhouse Gas Emissions through Recycling and Composting
10
-------
Table 2: Emissions Reduction Goals Relative to Potentials of Recycling and Composting
State 2050 annual emissions
goal (%)
1990 annual emissions
(MTCO2e)
Current annual emissions
(MTCO2e)
Based on most recent data
available
State 2050 annual emissions
goal (MTCO2e)
2050 annual emissions
reduction equivalency
Difference between current
emissions and 2050 annual
emissions goal
California
80% below 1990 levels17
427,000,000
477,700,00020
2008 emissions
85,000,000
(392,700,000)
Oregon
75% below 1990 levels18
55,811,000
68,058,00021
2007 emissions
13,952,750
(54,105,250)
Washington
50% below 1990 levels19
78,500,000
88,200,00022
2004 emissions
39,250,000
(48,950,000)
Lifetime emissions reduction potentials of materials wasted in one year (MTCO2e)
Carpet, core recyclables, and
dimensional lumber
(combined)
Food scraps
(17,233,016-23,665,424)
4-6% of 2050 annual
emissions reduction
(5,837,189)
1.5% of 2050 annual
emissions reduction
(806,623-1,144,938)
1-2% of 2050 annual
emissions reduction
(433,855)
0.8% of 2050 annual
emissions reduction
(2,036,382-3,004,271)
4-6% of 2050 annual
emissions reduction
(872,695)
1.8% of 2050 annual
emissions reduction
The California Environmental Protection Agency Air Resources Board has recently issued a draft
compost emissions reduction factor (CERF) as part of its rulemaking process for its AB 32 Mandatory
Commercial Recycling regulations. Whereas the WARM emissions factor for compost only considers
the carbon storage effects, the CERF includes emissions reductions due to decreased water use,
decreased soil erosion, and reduced fertilizer and herbicide use, as well as increased carbon storage
20 „
21 „
Office of the Governor of California, Executive Order S-3-05 (June 1, 2005).
5 Oregon H.B. 3543, 2007. http://www.leg.state.or.us/07reg/measpdf/hb3500.dir/hb3543.en.pdf
' Revised Code of Washington (RCW) 70.235.020. http://apps.leg.wa.gov/rcw/default.aspx?cite=70.235.020
"Trends in California Greenhouse Gas Emissions for 2000 to 2008." (California Air Resources Board, May 2010).
http://www.arb.ca.gov/cc/inventory/data/tables/ghgjnventory _trends_00-08_2010-05-12.pdf
"Oregon Greenhouse Gas Inventory, 1990-2007." (Oregon Department of Energy, 2010).
http://www.oregon.gov/ENERGY/GBLWRM/Oregon_Gross_GhG_lnventory_1990-2007.htm
" Stacey Waterman-Hoey and Greg Nothstein, "Greenhouse Gases in Washington State: Sources and Trends." (WA Department
of Community, Trade & Economic Development, December 2006).
"Proposed Method for Estimating Greenhouse Gas Emission Reductions from Compost from Commercial Organic Waste."
Planning and Technical Support Division, Air Resources Board. (California Environmental Protection Agency, August 31, 2010).
Reducing Greenhouse Gas Emissions through Recycling and Composting
11
-------
in soil. As a result, the CERF places the emissions reduction potential of compost at 0.42
MTCO2e/ton of food scraps, more than twice as high as the WARM factor of 0.20 MTCO2e/ton. If this
report's calculations were done using the CERF, the total emissions reduction potential of
composting food scraps would be even higher.
The WARM Calculator only evaluates the relative methane emissions reductions of open windrow
composting, but GHG emissions reductions can also be achieved by managing food scraps through
alternative composting methods (such as static aerated piles or enclosed systems) and by anaerobic
digestion. When anaerobically digested, food scraps can also be used as an alternative energy source.
The methane generated during decomposition can be captured and converted to a natural gas
equivalent fuel, or used to power a turbine to generate electricity.
Carbon Credits/Offsets
In addition to directly reducing emissions, composting and anaerobic digestion of food scraps may
also provide the opportunity to generating emissions offset credits. The Climate Action Reserve,
North America's largest carbon offset registry, issued an Organic Waste Digestion Protocol in 2009
and recently established an Organic Waste Composting Protocol. These protocols set standards for
the quantification and verification of GHG emissions reductions from composting and anaerobic
digestion projects.24 Projects adhering to the protocol and listed by the Reserve are eligible to sell
carbon offset credits, known as CRTs, generated from the projects and revenue from CRT sales can
help support private investment in composting and anaerobic digestion.25
Section 5. Additional Benefits of Recycling & Composting Priority Materials
The WARM results of this analysis reveal that materials management can help states achieve
emissions reductions. In addition, recycling and composting can contribute to other state and local
policy goals, such as job creation, economic development, and reducing land and marine pollution.
Job Creation and Economic Development
According to, "Recycling and Economic Development," a literature review conducted by Cascadia
Consulting Group for King County Solid Waste Division's LinkUp program, increasing recycling can
have positive benefits for job creation and economic development.
During a period in which many traditional manufacturing industries have been losing jobs in the U.S.,
several studies show that recycling has created manufacturing jobs, as well as jobs in recycling
24 For more information, visitwww.climateactionreserve.org/how/protocols/adopted/organic-waste-
digestion/current/ or
www.climateactionreserve.org/how/protocols/adopted/organic-waste-composting/current/
25The first composting offset project, "Z-Best Food Waste Composting," was listed by the Climate Action Reserve on
February 2. For more information, visitwww.cawrecycles.org/files/zanker.pdf
Cascadia Consulting Group, "Recycling and Economic Development: A Review of Existing Literature on Job Creation,
Capital Investment, and Tax Revenues." (King County Solid Waste Division LinkUp, April 2009).
Reducing Greenhouse Gas Emissions through Recycling and Composting
12
-------
27
processing. Additional research on the U.S. labor market suggests that recycling results in ten times
28
the jobs of waste disposal. And jobs in the recycling industry pay more, on average, than that
29
national average wage.
In 2001, CalRecycle (formerly the California Integrated Waste Management Board) released a study
showing that diverting a ton of recyclable or compostable material has approximately twice the
economic impact of sending it to a landfill. According to the report, diverting one additional ton of
waste would pay $101 more in salaries and wages, produce $275 more in goods and services, and
generate $135 more in sales than disposing of it in a landfill.
30
Using these figures, if just half of core recyclables and food scraps reported here that are currently in
the waste streams of California, Oregon, and Washington were recycled, that would result it almost
$1.6 billion in additional salaries and wages, $818 million in additional goods and services produced,
and $309 million in additional sales across the three states. These gains would translate into
additional revenue for state and local governments as well, through income, property, and sales taxes.
Table 3: Additional Revenue Potential from Recycling and Composting
Core Recyclables Est. Tons
Food Scraps Est. Tons
Additional Salaries and Wages
Additional Goods and Services
Additional Sales
TOTAL
4,580,295
7,536,505
$611,898,400
$1,666,060,000
$817,884,000
CALIFORNIA
3,904,101
6,158,120
$508,142,161
$1,383,555,388
$679,199,918
OREGON
180,860
457,709
$32,247,735
$87,803,238
$43,103,408
WASHINGTON
495,334
920,676
$71,508,505
$194,701,375
$95,580,675
Market values of several recyclable materials, such as cardboard and aluminum, have increased
substantially in the ten years since the CalRecycle analysis was conducted, meaning that the figures
above are lowered than might be expected today. Estimates of the job and economic benefits are not
available for carpet or dimensional lumber recycling, but they would also likely add hundreds of
millions more to these figures.
Reduced Land and Marine Pollution
According to the 2004 Washington State Litter Study, 1,125 tons of plastic or metal beverage containers,
cardboard, newspaper, magazines, food waste, carpet and wood were deposited on Washington
roadways. Together these materials accounted for 17.8% of the total material littered.
DSM Environmental Services and MidAtlantic Solid Waste Consultants (MSW). "Recycling Economic Information Study
Update." Prepared for the Northeast Recycling Council (NERC, 2009).
Seldman, Neil, Ph.D. "Recycling Sector Has 30-Year Record of Impressive Growth." (Institute for Local Self-Reliance, 2002).
3 R.W. Beck, "U.S. Recycling Economic Information Study." Prepared forthe National Recycling Coalition (NRC, 2001).
Goldman, George and Aya Ogishi, "The Economic Impact of Waste Disposal and Diversion in California." (California Integrated
Waste Management Board, April 4, 2001). http://are.berkeley.edu/extension/EconlmpWaste.pdf
1 Market prices for recyclable materials are published monthly by Resource Recovery.
1 Washington 2004 State Litter Study, "Litter Generation and Composition Report." Publication 05-07-029 (WA Solid Waste and
Financial Assistance Program, March 2005).
Reducing Greenhouse Gas Emissions through Recycling and Composting
13
-------
Marine pollution, demonstrated most visibly by the "Great Pacific Garbage Patch" in the northern
Pacific gyre, is now a major environmental concern. Research has found that the mass of plastics in
the gyre now exceeds the total mass of living creatures (plankton) by 6 to i. Worldwide, plastics
comprise 60 to 80 percent of marine debris on average, with some areas as high as 90 to 95 percent.
Urban runoff—material entering the water via storm drains or being swept or blown into the water-
is the primary source of marine debris and litter is the major source of trash in urban runoff. Litter
makes its way to the ocean through the storm drainage systems and waterways, by wind action and by
direct disposal into the water.
Any efforts that increase recycling and composting and reduce disposal and littering will help reduce
the amount of materials that end up in our waterways and oceans and reduce threats posed to the
animals that call the ocean their home.
Section 6. Opportunities for Reducing Emissions through Recycling and
Composting of Priority Materials
I. Carpet
Although carpet comprises only 3% of the waste stream in terms of tonnage in California, Oregon,
and Washington, it is a material with one of the highest emissions reduction potentials through
34
recycling in all three states. Carpet is made from natural gas and petroleum products and requires a
great deal of energy to produce. Most carpet in the U.S. is manufactured in Southern states, where
energy is derived largely from coal. The tremendous fossil fuel intensity of carpet inputs and
production makes the emissions of carpet manufacturing extremely high.
For many years, recycling carpet was technically challenging, expensive, and impractical. However,
new techniques and advances in recycling infrastructure are making recycling carpet more viable.
Several carpet manufacturers have developed processes for turning used carpet into new carpet, with
much lower life-cycle emissions than manufacturing with virgin content. Carpet can also be recycled
into other products, such as carpet pad or molded plastic parts (often for automobiles), also leading
to significant emissions reductions. However, carpet recycling requires source separation for clean,
high-value feedstock, which requires participation from private construction and demolition (C&D)
firms.
The U.S. carpet industry has had voluntary recycling programs in place for over a decade but recycling
rates remain relatively low. In 2002, members of the carpet industry, representatives of government
agencies at the federal, state and local levels, and non-governmental organizations signed a
Memorandum of Understanding for Carpet Stewardship (MOU) to improve carpet diversion and
recycling through voluntary product stewardship. Product stewardship is a product-centered approach
to environmental protection that calls on those in the product life cycle—manufacturers, retailers,
users, and disposers—to share responsibility for reducing the environmental impacts of products.
Gordon, M. "Eliminating land-based discharges of marine debris in California: a plan of action from the plastic debris project."
State Water Resources Control Board (California Coastal Commission, 2006).
Although there is some debate about the exact emissions reduction potential (see Appendix C), regardless of the emissions
factor used, carpet recycling clearly offers tremendous emissions reduction potential.
Reducing Greenhouse Gas Emissions through Recycling and Composting
14
-------
The agreement set an official goal of 40% landfill diversion, including a 20-25% recycling rate for
post-consumer carpet, by 2012, and established the Carpet American Recovery Effort (CARE) to
achieve these targets. An annual report published by CARE in 2009, however, revealed a growing gap
between the yearly goals for diversion and recycling and the actual levels reported. In 2009, for
example, the recycling rate missed CARE's 13% goal by 8.8%, with only a 4.2% rate being achieved.
Overall diversion (including combusting carpet for energy production) totaled only 5.3%, 15.7 points
lower than the 21% goal.
To achieve higher diversion rates, several states have begun exploring mandatory product
stewardship policies and in October 2010, the California legislature passed the first carpet product
stewardship bill in the country. AB 2398 requires every producer of carpet sold in the state of
California, individually or through a designated stewardship organization, to submit a stewardship
plan, including a funding mechanism that provides sufficient funding to carry out the plan, and to
demonstrate continuous meaningful improvement in the rates of recycling and diversion and other
36
specified goals in order to be in compliance.
37
In the Northwest, a similar bill, SB 5110 , was considered in the 2011 Washington legislative session.
In addition, state and local government groups have formed the Northwest Carpet Recycling
Workgroup in 2009, which is actively working to increase demand for carpet recycling and products
made with recovered carpet fiber, and to encourage carpet processing facilities to become established
in the northwest for economic development and easier carpet recycling. The effort, along with the
significant contributions of private industry, has been successful and new carpet recycling facilities
have opened in the area.
In 2009 CARE initiated another round of negotiations to develop a new ten-year MOU agreement
among stakeholders toward setting and meeting new carpet landfill diversion goals.
Since the first municipal recycling programs began in the igyo's, curbside collection of recyclables
has spread throughout the West Coast and across the United States. A recent survey estimates that
74% of the U.S. population currently has access to curbside recycling collection. Although the types
of materials included in curbside recycling varies from place to place, most programs cover a core set
of recyclable materials including aluminum and steel food and beverage containers, newspapers,
magazines, high-grade paper, corrugated cardboard containers, and #1 and #2 plastic bottles. Many
curbside recycling programs also accept glass containers and a wider array of paper and plastic types.
Cities with the most successful curbside recycling programs have used variable rate pricing structures
40
to incentivize recycling participation. This approach, often called "Pay As You Throw," or PAYT, sets
"A Decade of New Opportunities: Developing Market-Based Solutions for the Recycling and Reuse of Post-Consumer
Carpet." (CARE, 2009).
36 "Fact Sheet -AB 2398 (Perez, 2010) Carpet Producer Responsibility." (California Product Stewardship Council, 2010).
For the text of SB 5110, visit http://apps.leg.wa.gov/billinfo/summary.aspx?bill=5110&year=2011
38 For more information about the Northwest Carpet Recycling Workgroup, visit
http://your.kingcounty.gov/solidwaste/linkup/carpet/project.asp
39 "2008 ABA Community Survey." Produced for the American Beverage Association, (R.W. Beck, September 2009).
Canterbury, Janice and Sue Eisenfeld, "The Rise and...Rise of Pay-As-You-Throw." (MSW Management, 2006).
Reducing Greenhouse Gas Emissions through Recycling and Composting 15
-------
garbage collection charges on a per unit or weight basis, rather than charging a flat fee for unlimited
garbage collection. In addition, most PAYT programs provide recycling collection at free or reduced
rates, making it economically attractive for waste generators to divert recyclable materials from
landfill disposal. Communities with PAYT programs in place have reported significant increases in
recycling and reductions in waste. Overall, PAYT programs have been shown to reduce disposal by
41
about 17%, with 5-6% being directly diverted to recycling.
West Coast cities have been leaders in instituting PAYT programs, and as a result these programs are
widespread throughout the region. In fact, a recent survey of PAYT programs for the EPA estimates
that virtually all communities in Washington and Oregon have PAYT programs in place, while half of
California communities have them.
Curbside residential recycling programs in West Coast states continue innovating to increase
participation and reduce contamination through public information and outreach, including focused
social marketing. And Los Angeles recently began piloting a rewards-based approach in partnership
43
with Recyclebank. Recyclebank has been successful in increasing diversion of recyclables in
Philadelphia, Cincinnati, and other large cities.
Although California, Oregon, and Washington have high diversion rates of recyclable materials
compared to the national average, increasing recycling of core recyclables in these states can still
deliver important benefits, such as emissions reduction, cost savings, and jobs. As this analysis
shows, recyclable materials still appear in the disposed waste stream of West Coast states. In
California, Oregon, and Washington, core recyclables make up 7-10% of disposed waste by weight,
and are responsible for 33-55% of all emissions found in this analysis to be attributable to the top ten
materials in each state. This suggests that there remains significant room for improvement in
recycling programs and policies targeting diversion of core recyclables.
Although already recycled at high rates, corrugated containers continue to appear in the waste
streams of all three states in large quantities. Corrugated containers embody the third greatest
emissions reduction potential of all materials currently landfilled, and represent a valuable recyclable
commodity. An analysis of the waste characterization studies in California and Washington, which
break their state waste data into substreams by source, reveals that corrugated containers come
44
predominantly from commercial generators.
In California, although commercial sources are responsible for only 50% of total waste, the
commercial substream generates 75% of all corrugated containers. In Washington, the commercial
sector generates 44% of total waste but 55% of all corrugated containers.
While residential recycling programs are mandatory in many places, commercial recycling remains
largely voluntary, making it difficult for local and state governments to increase the diversion of
Skumatz, Lisa, "Variable-Rate or 'Pay-As-You-Throw' Waste Management: Answers to Frequently Asked Questions." Policy
Study #295 (Reason Public Policy Institute, 2002).
42 Skumatz, Lisa and David Freeman, "Pay as you Throw (PAYT) in the US: 2006 Update and Analyses." Prepared for US EPA and
SERA, (Skumatz Economic Research Associates, December 2006).
43 Carpenter, Susan, "LA Will Reward Recycling Through New Recyclebank Program." LA Times, February 24, 2010.
http://latimesblogs.latimes.com/greenspace/2010/02/recycling-rewards-los-angeles.html
See Appendix D for a breakdown of tonnage in California and Washington by commercial and residential substreams.
Reducing Greenhouse Gas Emissions through Recycling and Composting 16
-------
recyclable materials from the commercial waste stream. Recognizing the potential of increased
recycling to reduce greenhouse gas emissions, California has begun taking steps to mandate
commercial recycling statewide. The Mandatory Commercial Recycling Measure, being developed by
CalRecycle as part of its implementation of the California Global Warming Solutions Act of 2006
(AB 32), would require businesses generating 4 or more cubic yards of trash and/or recyclables for
weekly collection to receive recycling services. This measure is intended to achieve GHG reductions
of 5 million MTCO26.
Dimensional lumber is among the most easily diverted wood types, and is nonetheless disposed of in
sufficiently large volume to rank among the top ten materials with emissions reduction potential in
each of the three West Coast states. Wood comprises a surprisingly large portion of organic materials
disposed of in landfills. The broad category of wood in waste characterization studies includes many
different types of materials, such as "clean" (unpainted/untreated) lumber, painted/treated lumber,
hogfuel, pallets, crates, and wood furniture. Some of these wood types, such as clean lumber, could be
more easily diverted from disposal through recycling than others. Because of this, the WARM
Calculator—and thus this analysis—focuses only on clean dimensional lumber.
Dimensional lumber is a construction and demolition (C&D) waste with relatively good recycling
options. According to CalRecycle (formerly California Integrated Waste Management Board), this
type of wood waste is highly desirable and is sought by processors.45 Lumber scraps generated during
construction make an excellent feedstock for engineered wood, and can also be recycled into products
such as laminates, parquet, pallets, countertops, shelving, furniture, mulch, wood pellets, and
fiberboard.4 Some dimensional scraps can be reused in non-load bearing construction.
Much processed lumber currently ends up as biomass fuel, and is not recycled back into wood
products. This prevents the emission of methane from wood waste aerobically decomposing in
landfills, and can replace the need for fossil fuels, but does not offer the benefit in reducing the
impact of manufacturing of new wood products that recycling does.
As with carpet, recycling dimensional lumber requires source separation for clean, high-value feedstock,
and thus requires participation from private C&D firms. This can be challenging for these firms, especially
during demolition, when clean, reusable lumber and unrecyclable debris are often intermingled.
Local and state governments can improve lumber recycling practices by establishing C&D recycling
requirements, providing education and information about the recycling process and available
markets, and by supporting innovation in C&D processes that improve recycling opportunities.
For example, California's new CalGreen statewide building code requires at least 50 percent
construction materials diversion from each residential or commercial project.47 Governments can also
support market development of production of and demand for recycled wood products using locally
recovered and processed dimensional lumber. Going beyond lumber recycling, governments can
"Chapter 9: Wood & Organic Waste," from Best Practices in Waste Reduction. (California Integrated Waste Management
Board, 2009). www.calrecycle.ca.gov/Video/2009/BestPracCh9.pdf
46 Sherman-Huntoon, Rhonda, "Wood Waste Study Provides Clues to Recycling Success." BioCycle vol. 42, n.7, p.68 (July 2001).
For more information, visit www.calrecycle.ca.gov/LGCentral/Library/canddmodel/instruction/faq.htmttdiversion
Reducing Greenhouse Gas Emissions through Recycling and Composting 17
-------
promote deconstruction, an alternative method for building removal that preserves materials and
encourages the reuse of wood products.48
IV, F<
As mentioned previously, food scraps are a major source of methane emissions from landfills.
Because food decomposes relatively quickly, food scraps often begin releasing methane before landfill
methane collection systems can be installed. States can reap meaningful and direct emission
reductions from alternative management of food scraps. Food scraps are the single largest volume of
material, by weight, disposed in landfills in California, Oregon, and Washington.
More than 90 towns and cities in the U.S. offer single-family residential food waste collection for
composting and West Coast cities lead the pack.49 Many of these communities also have commercial
composting programs in place as well. Commercial sources can be used to initiate composting
programs, as they offer large volumes of source-separated food, a model followed by San Francisco and
other communities in California. Food scrap composting not only delivers emissions reductions, it
offers potential cost savings as well. Seattle Public Utilities estimates that its program costs about 20%
less per load than landfilling. In 2009, this translated into a savings of approximately $25O,ooo.5°
Compost produced by food scraps offers several additional benefits during its use, including reducing or
eliminating the need for chemical fertilizers, improving soil porosity and water retention, facilitating
reforestation and habitat restoration, and bioremediation, and promoting higher yields of agricultural
crops. As mentioned above, the WARM emissions factor leaves out a number of benefits from
composting, including emissions reductions from decreased water use, decreased soil erosion, and
reduced fertilizer and herbicide use. If these components were included, as they are in the California Air
Resources Board's methodology, the emissions reduction potential of food scraps would be even
greater51. ARB's analysis estimates 0.42 MTCO2e reduction for every ton composted, without considering
landfill methane avoidance. For further discussion of WARM and composting, see Appendix E.
As discussed earlier, GHG emissions reductions can also be achieved by diverting food scraps to
anaerobic digestion. The emissions reduction potential of anaerobic digestion is not presented here
because it is not included in the WARM Calculator. On the West Coast, the East Bay Municipal Utility
District is currently investigating the possibility of of anaerobically co-digesting food waste at its main
wastewater treatment plant.52And, in Washington, Cedar Grove Composting is seeking a permit to use
anaerobic digestion to convert food and yard scraps into biogas to produce electricity and natural gas.53
Environment Canada commissioned an evaluation of the life-cycle GHG benefits of composting and
anaerobic digestion, and found that if one considers the carbon storage benefits of compost,
For more information, visit www.epa.gov/osw/conserve/rrr/imr/cdm/reuse.htm
Yespen, Rhodes, "U.S. Residential Food Waste Collection and Composting." Biocycle vol. 50, n.12, p.35 (December 2009).
50 Bloom, Jonathan, "American Wasteland." p. 295 (Da Capo Press, 2010).
51 "Proposed Method for Estimating Greenhouse Gas Emission Reductions from Compost from Commercial Organic Waste."
Planning and Technical Support Division, Air Resources Board. (California Environmental Protection Agency, August 31, 2010).
52 U.S. EPA, "Turning Food Waste into Energy at the East Bay Municipal Utility District (EBMUD)."
http://www.epa.gov/region9/waste/features/foodtoenergy/
"Cedar Grove Composting Announces Partnership with BIOFerm." BIOFerm blog (July 7, 2010).
http://www.biofermenergy.com/us/blog/?p=225
Reducing Greenhouse Gas Emissions through Recycling and Composting 18
-------
composting is preferable to anaerobic digestion, although both reduce emissions relative to
landfilling (given average Canadian conditions).54 Food anaerobic digestion operations can combine
digestion with composting, taking advantage of the carbon storage role of compost and avoiding
landfill disposal of digestion residuals. A proposed San Jose facility would combine dry fermentation
anaerobic digestion with in-vessel composting.55
However, compost facilities can be problematic if not operated optimally. This can lead to emissions
of VOCs, as well as odor and vector issues, undermining community support. Best practices have
been developed by the U.S. Composting Council under a grant from the EPA that suggest how to
minimize odor and other potential issues through proper aeration, feedstock management,
carbon/nitrogen balance and covering rows with finished compost.5 However, in some regions,
anaerobic digestion of food waste may be a better option.57
Also, although not measured in the WARM Calculator, there are opportunities to "recycle" food by
diverting what is discarded by grocery stores and commercial food service operations to food banks
and soup kitchens. So-called "food rescue" programs exist in many communities for coordinating the
collection and distribution of discarded pre-consumer food waste.58 These programs deliver the
benefits of waste prevention while providing a valuable resource to people in need.
Of course, as with all of the top ten materials, reducing the amount of food wasted overall delivers
powerful emissions reductions as well. In a successful example from abroad, the UK's "Love Food,
Hate Waste" campaign, spearheaded by the British government, has engaged citizens with
information and educational outreach on how to waste less food. Since its launch in 2009, the
campaign estimates that it has reduced 2.8 million MTCO2e.59
Estimates for the U.S. suggest that between 26% and 40% of all available food is wasted. ° Preventing
that waste is a huge opportunity for emissions reductions and cost savings for individuals and
governments alike.
54 ICF Consulting, "Determination of the Impact of Waste Management Activities on Greenhouse Gas Emissions: 2005 Update,
Final Report." Prepared for Environment Canada and Natural Resources Canada (October 2005).
55 For more information, visit http://zerowasteenergy.com/content/san-jose-anaerobiic-diigestiionconipostiing-pllant
56 Christiansen, Eva, "Best Management Practices for Incorporation Food Residuals into Existing Yard Waste Composting
Operations." (U.S. Composting Council, 2009).
CalRecycle's final Program Environmental Impact Report for anaerobic digestion facilities will be published in May 2011. This
Program EIR assesses the environmental effects that may result from the development of anaerobic digestion facilities in
California. The results of the Program EIR will inform future policy considerations related to anaerobic digestion facilities and
provide background information on technologies, potential impacts, and mitigation measures. For more information, visit
http://www.calrecycle.ca.gov/swfacilities/Compostables/AnaerobicDig/default.htm
58 Examples of these programs include Food Lifeline's Grocery Rescue program in Western Washington and Metro's Fork It Over
program in the Portland metropolitan area.
59 Personal communication with Andrew Parry, Household Food Waste Programme Manager, WRAP UK. January 20, 2011.
Kantor, Lisa Scott et al. "Estimating and Addressing America's Food Losses," Food Review, January-April 1997, pp.2-12 (USDA
Economic Research Service, 1997).
Reducing Greenhouse Gas Emissions through Recycling and Composting 19
-------
The WARM results presented in this report provide policymakers and materials management
professionals in California, Oregon, and Washington a good idea of which materials carry the greatest
potential for emissions reduction if diverted from landfill disposal through recycling or composting.
At a time when limited resources are available for meeting multiple urgent policy goals, programs
that focus on diverting these priority material types from landfill disposal through recycling or
composting can deliver emissions reductions and contribute to climate action goals, while producing
other more widely accepted benefits such as resource conservation, cost savings, job creation and
economic development.
Although recycling is an established practice in many West Coast communities, this report shows that
further progress can be made, both to divert greater quantities of materials currently being recycled
and to establish new programs for additional materials. For some materials, such as carpet and
dimensional lumber, effective materials management strategies and mechanisms are relatively new
or still being developed and more research and experimentation is needed to understand how
communities can recycle these materials most effectively. Likewise, food scrap management offers
new and rapidly evolving opportunities. Further research and evaluation of on-the-ground results
will be important for helping communities determine how best to divert food scraps from landfills
and reap the GHG emissions reductions benefits. Even best practices for core recyclables are
undergoing change, such as a transition to single-stream collection and processing systems and
expansion of mandatory recycling to the commercial sector.
Meeting these opportunities will require expansion of processing, reuse, and manufacturing
infrastructure. The West Coast is deficient in food composting and anaerobic digestion facilities,
although several composting and digestion facilities employing various technologies are either
planned or under construction. Many traditional recycled materials are exported rather than utilized
domestically at the same time that domestic recyclers are in need of more materials. While increasing
diversion and recycling of more materials will generate more jobs domestically in the collection,
transport, sorting and marketing areas, the material will need to be recycled domestically to have the
greatest impact on job creation and economic activity. Reuse opportunities can also be expanded,
especially for deconstructed building materials.
These changes create challenges as well as opportunities, and necessitate continued innovation and
improvements. The Materials Management Workgroup of the West Coast Climate and Materials
Management Forum is committed to continuing to provide research and information on current
strategies and best practices in recycling and composting of these priority materials.
Si id
The analysis featured here estimates the emissions reduction potential of recycling and composting
various materials versus depositing them in a landfill, but it does not provide a comprehensive
comparison of other life-cycle materials management strategies, such as green purchasing, producer
responsibility, product stewardship, and decreased consumption, except to the extent that these
strategies might be used to achieve the recycling results simulated in the model's recycling scenario.
Reducing Greenhouse Gas Emissions through Recycling and Composting 20
-------
The analysis also fails to capture the significant GHG emissions reduction that can be achieved
through changes to materials management-related issues such as transportation modes,
manufacturing practices, distribution infrastructure, energy sources, and product design.
To fully understand the emissions reduction potential of sustainable materials management, the
entire spectrum of strategies available across the entire life cycle of materials must be examined. The
workgroup looks forward to the opportunity to focus on these strategies in future projects.
Reducing Greenhouse Gas Emissions through Recycling and Composting 21
-------
APPENDIX A: State Waste Tonnage Data by WARM Category
WARM v.ll
California
Oregon
Washington
Material
Categories
Aluminum Cans
Steel Cans
Glass
HDPE
LDPE
PET
Mixed Plastics
Corrugated
Containers
Magazines/
Third-class Mail
Newspaper
Office Paper
Phonebooks
Dimensional
Lumber
2008 CA Waste
Characterization
Study, Table 50
Aluminum Cans
Tin/Steel Cans
Glass (Combined)
Clear Glass Bottles and
Containers
Green Glass Bottles and
Containers
Brown Glass Bottles and
Containers
Other Glass Bottles and
Containers
Flat Glass
HDPE Containers
not available
PETE Containers
(Combined)
PETE Water Bottles
PETE Sealed Containers
Other PETE Containers
not applicable
Uncoated Corrugated
Containers
Magazines and
Catalogs
Newspaper
Office Paper
(Combined)
White Ledger Paper
Other Office Paper
Phone Books and
Directories
Clean Dimensional
Lumber
Est. Tons
47,829
236,405
459,006
196,093
79,491
108,953
40,570
33,899
157,779
na
199,643
51,706
18,477
129,460
N/A
1,905,897
283,069
499,960
731,298
259,151
472,147
24,149
1,184,375
2009 OR Waste
Composition Study
Aluminum Cans
Steel (Tinned) Cans
Glass (Combined)
Depost Beverage Glass
No- Deposit Glass
Containers
Flat Window Glass
not available
not available
not available
Plastic (recyclable)
acceptable at curb
Cardboard
(Combined)
Cardboard Packaging
Paper
Waxed Corrugated
Cardboard
Magazines
Newspaper
High Grade Paper
not available
Unpainted Lumber
Est. Tons
2,937
18,158
40,925
6,818
23,964
10,143
na
Na
na
28,035
75,266
72,652
2,614
15,030
18,640
22,794
na
71,555
2009 WA Waste
Characterization Study,
Table 9
Aluminum Cans
(Combined)
Aluminum Beverage Cans
Food Cans -Coated
Food Cans -Tinned
Glass (Combined)
Clear Glass Containers
Green Glass Containers
Brown Glass Containers
Plate Glass
HDPE (Combined)
#2 HDPE Plastic Natural Bottles
#2 HDPE Plastic Colored Bottles
#2 HDPE Plastic Jars & Tubs
#2 HDPE Plastic Products
LDPE (Combined)
#4 LDPE Plastic Packaging
#4 LDPE Plastic Products
PETE (Combined)
#1 PETE Plastic Bottles
#1 PETE Plastic Non-Bottles
#1 PETE Plastic Products
not applicable
Corrugated Containers
(Combined)
Cardboad/Kraft Paper
Packaging
Cardboard/Kraft Paper
Products
Magazines
Newspaper (Combined)
Newspaper
Newspaper Packaging
High-Grade Paper
Products
Other Groundwood Paper
Products
Dimensional Lumber
Est. Tons
28,085
23,031
5,054
35,772
73,517
42,353
8,592
17,490
5,082
51,467
12,547
17,017
20,020
1,883
445
329
116
48,079
33,344
14,563
172
N/A
189,205
185,311
3,894
46,149
82,682
70,594
12,088
49,667
13,874
51,929
Reducing Greenhouse Gas Emissions through Recycling and Composting
22
-------
WARM v.ll
California
Oregon
Washington
Material
Categories
Food Scraps
Yard Trimmings
Grass
Leaves
Branches
Carpet
Personal
Computers
Concrete
Fly Ash
Tires
Asphalt
Concrete
Asphalt Shingles
Drywall
TOTAL
2008 CA Statewide
Waste
Characterization
Study, Table 50
Food
Prunings and
Trimmings
not applicable
Leaves and Grass
Branches and Stumps
Carpet
Computer-related
Electronics
(Combined)
Computer-related
Electronics - Large
Computer-related
Electronics-Small
Concrete
Ash
Tires (Combined)
Vehicle and Truck Tires
Other Tires
Asphalt Paving
Asphalt Roofing
(Combined)
Asphalt Composition
Shingles
Roofing Tar Paper/Felt
Roofing Mastic
Built-up Roofing
Other Asphalt Roofing
Material
Gypsum Board
(Combined)
Clean Gypsum Board
Painted/Demolition
Gypsum Board
Est. Tons
6,158,120
1,058,854
N/A
1,512,832
245,830
1,285,473
32,931
26,357
6,574
483,367
40,736
60,180
23,627
36,553
129,834
1,121,945
637,912
100,648
18,559
108,162
256,664
642,511
449,097
193,414
18,502,023
2009 OR Statewide
Waste Composition
Study
Food (Combined)
Food not otherwise
specified
Non-packaged bakery
goods
Packaged bakery goods
Non-packaged other
vegetative food
Packaged other
vegetative food
Non-packaged non-
vegetative food
Packaged non-vegetative
food
All Prunings and
Stumps
Grass Clippings
Leaves/Weeds
not available
Carpet/Rugs
Computers &
Monitors
Rock, Concrete
not available
Tires
Not
Asphalt Roofing &
Tarpaper
Gypsum Wallboard
Est. Tons
457,709
254,896
13,312
12,638
97,084
30,609
31,979
17,191
25,473
40,737
55,169
na
67,610
4,776
31,168
na
4,773
101,246
73,593
1,155,594
2009 WA Statewide
Waste Characterization
Study, Table 9
Food (Combined)
Food - Vegetative
Food - Non-Vegetative
Fruit Waste
Prunings
n/a
Leaves & Grass
n/a
Carpet
Computers (Combined)
Computer Monitors - CRT
Computer Monitors - LCD
Computers
Concrete
Ash
Tires & Rubber
Asphalt Paving
Asphalt Roofing
Drywall
Est. Tons
920,676
654,458
258,823
7,395
26,941
203,909
145,282
3,090
1,476
322
1,292
10,917
7,889
15,216
9,676
62,215
131,475
2,208,157
Reducing Greenhouse Gas Emissions through Recycling and Composting
23
-------
Appendix B: WARM Per Ton Emissions Estimates for Alternative
Management Scenarios
Material
Aluminum Cans
Steel Cans
Copper Wire
Glass
HOPE
LDPE
PET
Corrugated Containers
Magazines/
Third-class mail
Newspaper
Office Paper
Phonebooks
Textbooks
Dimensional Lumber
Medium-density
Fiberboard
Food Scraps
Yard Trimmings
Grass
Leaves
Branches
Mixed Paper
Mixed Metals
Mixed Plastics
Mixed Recyclables
Mixed Organics
Mixed MSW
Carpet
Personal Computers
Clay Bricks
Concrete
Fly Ash
Tires
Asphalt Concrete
Asphalt Shingles
Drywall
Vinyl Flooring
Wood Flooring
GHG Emissions per
Ton Source
Reduced
(MTCO2E)
(8.26)
(3.19)
(7.38)
(0.53)
(1.77)
(2.25)
(2.07)
(5.60)
(8.65)
(4.89)
(8.00)
(6.29)
(9.13)
(2.02)
(2.23)
0.00
0.00
0.00
0.00
0.00
NA
NA
NA
NA
NA
NA
(4.02)
(55.78)
(0.29)
NA
NA
(4.34)
(0.11)
(0.20)
(0.22)
(0.63)
(4.08)
GHG Emissions
perTon
Recycled
(MTCO2E)
(13.61)
(1.80)
(4.97)
(0.28)
(1.38)
(1.67)
(1.52)
(3.10)
(3.07)
(2.80)
(2.85)
(2.65)
(3.11)
(2.46)
(2.47)
NA
NA
NA
NA
NA
(3.51)
(5.40)
(1.50)
(2.87)
NA
NA
(7.22)/(2.21)*
(2.26)
NA
(0.01)
(0.87)
(0.39)
(0.08)
(0.09)
0.03
NA
NA
GHG Emissions
perTon
Landfilled
(MTCO2E)
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.08
(0.42)
(0.97)
1.38
(0.97)
1.38
(0.66)
(0.66)
0.75
(0.11)
0.28
(0.54)
(0.66)
0.05
0.04
0.04
(0.05)
0.31
1.15
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.13
0.04
0.07
GHG Emissions
perTon
Combusted
(MTCO2E)
0.05
(1.55)
0.04
0.04
1.73
1.73
1.50
(0.35)
(0.24)
(0.40)
(0.33)
(0.40)
(0.33)
(0.42)
(0.42)
(0.07)
(0.10)
(0.10)
(0.10)
(0.10)
(0.35)
(1.06)
1.63
(0.29)
(0.09)
0.05
0.96
(0.13)
NA
NA
NA
0.51
NA
(0.34)
NA
(0.15)
(0.55)
GHG Emissions
perTon
Composted
(MTCO2E)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
(0.20)
(0.20)
(0.20)
(0.20)
(0.20)
NA
NA
NA
NA
(0.20)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NOTE: Categories that appear in parentheses are net emissions reductions, while others are net emissions increases.
* See Appendix Cfor an explanation of the two emissions factors used for carpet recycling
Reducing Greenhouse Gas Emissions through Recycling and Composting
24
-------
APPENDIX C: Concerns with WARM Emissions Factor for Carpet Recycling
The first emissions factor for carpet recycling (7.22 MTCO2e net emissions reduction) comes from
the WARM Calculator and assumes an open loop recycling process. A number of industry and
government stakeholders have expressed concerns with the assumptions used in the development in
the emissions factor. Specifically, there are three major concerns:
i) The WARM factor was developed using data about the material composition of residential
carpet, which is significantly different from commercial carpet. Because residential carpet
makes up a minority of carpet in the waste stream (only 22% of carpet landfilled in California
is from the residential sector, and only 10% in Washington is), the use of residential carpet
data may be misleading.
2) The WARM factor calculation assumes that carpet recycling is an "open loop" process, and
that carpet is recycled in the following proportions: 67% is recycled into carpet pad, 25% is
recycled into molded plastic parts, and 8% is recycled into carpet tile backing. These
assumptions do not match the latest reports from the carpet industry about how carpet is
recycled. According to the Carpet American Recovery Effort (CARE) 2009 Annual Report,
carpet is recycled as follows: 45% is turned back into carpet, 33% is recycled into plastic
pellets (used in plastic product manufacturing), 12% is recycled into carpet pad, 5% is
recycled directly into molded plastic parts, 4% is recycled into other products, and 1% is used
as engineered fuel.
3) The WARM factor calculation assumes that the current mix of inputs for carpet
manufacturing is 100% virgin materials. With 45% of all recycled carpet being recycled back
into carpet, this is clearly not entirely accurate. However, as of 2009, only 4.2% of all post-
consumer carpet is recycled, so it is likely that most carpet manufacturing includes little if
any recycled content.
The U.S. EPA is aware of the limitations and potential flaws in the WARM emissions factor for carpet
recycling and is working with experts in the industry and academic community to revise these factors
for future versions.
In the meantime, we have chosen to calculate the emissions reduction potential for carpet in two
ways. First, we continue using the WARM emissions factor for consistency and because the
assumptions and calculations are transparent and freely available for review and critique at
http://www.epa.gov/climatechange/wycd/waste/downloads/carpet-chapter10-28-10.pdf.
Second, we use an emissions factor for closed loop carpet recycling (2.2iMTCO2e net emissions
reduction for carpet recycled back into carpet) developed by Dr. Jeffrey Morris of Sound Resource
Management in a report to Seattle Public Utilities titled, "Environmental Impacts from Carpet
Discards Management Methods: Preliminary Results."
Because neither the assumptions used for WARM nor Dr. Morris's analysis accurately reflect the
nature of the carpet recycling market today, both emissions factors present skewed estimates of the
emissions reduction potential of recycling carpet currently in the waste stream in WA, OR, and CA.
Unfortunately, they represent the best estimates currently available for public use. We hope that by
providing both in our analysis, we reflect the range of estimated emissions reduction potential for
carpet recycling.
Reducing Greenhouse Gas Emissions through Recycling and Composting
25
-------
APPENDIX D: Proportions of Waste from Commercial and Residential
Substreams in California and Washington
CALIFORNIA 2008
61
Material
Categories
TOTAL TONS
Carpet
Core Recyclables
Aluminum Cans
Steel Cans
HOPE
LDPE
PET
Corrugated
Containers
Magazines
Newspaper
Office Paper
Dimensional
Lumber
Food Scraps
All Sectors
(tons)
39,722,818
1,285,473
4,061,880
47,829
236,405
157,779
n/a
199,643
1,905,897
283,069
499,960
731,298
1184375
6,158,120
Commercial
(tons)
19,672,547
697,461
2,481,237
20,169
113,789
74,261
n/a
89,176
1,423,530
117,828
190,237
452,247
730278
3,032,805
%
50%
54%
61%
42%
48%
47%
n/a
45%
75%
42%
38%
62%
62%
49%
Residential
(tons)
11,935,174
278,641
1,338,042
26,171
115,921
78,845
n/a
105,169
323,059
153,432
288,197
247,248
74,475
3,034,040
%
30%
22%
33%
55%
49%
50%
n/a
53%
17%
54%
58%
34%
6%
49%
Multi-Family
(tons)
3,351,428
159,536
487,042
4,561
30,862
31,186
n/a
34,922
147,048
40,627
99,735
98,101
22663
756,846
%
8%
12%
12%
10%
13%
20%
n/a
17%
8%
14%
20%
13%
2%
12%
Single-Family
(tons)
8,583,746
119,105
851,000
21,610
85,059
47,659
n/a
70,247
176,011
112,805
188,462
149,147
51812
2,277,194
%
22%
9%
21%
45%
36%
30%
n/a
35%
9%
40%
38%
20%
4%
37%
WASHINGTON 2009
Material
Categories
TOTAL TONS
Carpet
Core Recyclables
Aluminum Cans
Steel Cans
HOPE
LDPE
PET
Corrugated
Containers
Magazines
Newspaper
Office Paper
Dimensional
Lumber
Food Scraps
All Sectors
(tons)
4,978,496
145,282
531,551
28,085
35,772
51,467
445
48,079
189,205
46,149
82,682
49,667
51,929
920,676
Commercial
(tons)
2,174,075
87,897
248,158
10,064
16,266
25,016
95
16,714
103,609
16,108
31,615
28,671
16,942
484,521
%
44%
61%
47%
36%
45%
49%
21%
35%
55%
35%
38%
58%
33%
53%
Residential
(tons)
1,826,521
14,222
212,768
15,927
17,999
22,745
186
29,071
46,208
23,302
38,643
18,687
1,551
414,006
%
37%
10%
40%
57%
50%
44%
42%
60%
24%
50%
47%
38%
3%
45%
California 2008Statewide Waste Characterization Study (Cascadia Consulting Group for CA Integrated Waste Management
Board, 2009).
" 2009 Washington Statewide Waste Characterization Study (Cascadia Consulting Group for WA Department of Ecology, 2010).
Reducing Greenhouse Gas Emissions through Recycling and Composting
26
-------
APPENDIX E: Benefits and Limitations of WARM Model
From "Materials Management Approaches for State and Local Climate Protection"
http://captoolkit.wikispaces.com/WARM
EPA's Waste Reduction Model (WARM) is a tool for assessing the GHG emissions of a baseline and
an alternative waste management method for handling any of 32 materials and 8 mixed materials
categories. It was created to help solid waste planners and organizations track and voluntarily repo rt
GHG emissions reductions from several different waste management practices. WARM is publicly
available both as a Web-based calculator and as a Microsoft Excel spreadsheet.
WARM calculates and totals GHG emissions of baseline and alternative waste management practices
(i.e. landfilling, incineration, source reduction, recycling, and composting). The model calculates
emissions in metric tons of carbon equivalent (MTCE), metric tons of carbon dioxide equivalent
(MTCO2E), and energy units (million BTU) across 40 material types commonly found in municipal
solid waste (MSW). The emission factors represent the GHG emissions associated with managing i
short ton of MSW in a specified manner. GHG savings must be calculated by comparing the emissions
associated with the alternative scenario with the emissions associated with the baseline scenario.
Without the comparison, part of the emissions savings or cost will be excluded.
The model takes a life cycle view and incorporates in the emissions factors for each material the
emissions from raw materials acquisition, processing, manufacturing, transportation, and end-of-life
management. However, the use phase of materials is not considered in the model's calculations. For
most materials, recycling is modeled as a closed-loop. For example, a plastic PET bottle is recycled
into a plastic PET bottle. For those materials where there is not a dominant use of a recycled material
or a lack of data, an open-looped process maybe modeled. Open-loops are common for many of the
paper-based material categories. Details for what is and isn't included can be found in the FAQ.
(http://www.epa.gov/climatechange/wycd/waste/calculators/WARM_faq.html)
WARM is widely used by national, state, and local governments. Because it is commonly used, it
lends some universality and comparability to the analyses that are done with it. It is a "common
denominator" for solid waste GHG emissions in the US. Other available tools sometimes have
drawbacks that WARM does not; they may be proprietary and accessed only through contract, may
carry costs for use, and may not be as widely used.
Although it remains one of the best options available for state and local governments to estimate the
emissions reduction potential of recycling, composting, and source reduction (relative to incineration
and landfilling), WARM is not without limitations. Here are some that have implications for this report:
WARM and Materials Categories
WARM users face the challenge of reconciling their own materials category definitions with those the
model employs. WARM's categories for mixed paper and corrugated cardboard remain ambiguous
since there are a many materials with different emissions impacts that would fall into these
categories in varying ratios.
Reducing Greenhouse Gas Emissions through Recycling and Composting
27
-------
WARM and Products
WARM focuses on materials, not products, which leaves out some significant pieces of the solid waste
stream. It doesn't, for example, include such categories as sheetrock, textiles (which can have
multiple materials in products) or household items - furniture, toys, sporting goods, electronics
other than PCs. Material list is found on the WARM homepage:
http://www.epa.gov/climatechange/wycd/waste/calculators/Warm_home.html
WARM and Alternative Materials Management
Some materials management efforts are better evaluated using other methods and tools. WARM is
not easily adapted to comprehensive comparisons of materials management strategies such as
product stewardship, EPP or reuse programs. For example, the lack of "upstream" (or production-
related) emissions for food limits WARM's utility for evaluating food waste prevention projects. Also,
WARM currently has no capacity to calculate reuse separate from source reduction. The source
reduction management option assumes materials not manufactured. Using the source reduction
calculations as a proxy for reuse activities only works if one assumes that the reuse actually
substitutes for the mining and manufacture of virgin materials that would have otherwise been
necessary. This is a shaky assumption, since some reuse activities don't actually displace production
of new materials.
WARM and Methane Global Warming Potential (GWP)
GWP is a concept designed to compare the ability of a greenhouse gas to trap heat in the atmosphere
relative to another gas. The definition of a GWP for a particular greenhouse gas is the ratio of heat
trapped by one unit mass of the greenhouse gas to that of one unit mass of CO2 over a specified time
period. WARM uses 21 as the GWP for methane, which is the 100 year GWP listed in the IPCC's
second assessment from 1996. According to the EPA, November 2009, this will not be changed
anytime soon as the GWP is set by the United Nations Framework Convention on Climate Change
(UNFCCC) which EPA must use for national GHG inventories (and which is based on the IPCC
second assessment). It is important to note that the more recent IPCC Assessment 4 (2007) uses a
100 year GWP for methane of 25. However, many state and local inventory and waste professionals
believe that using a 20 year horizon GWP of 72 for methane highlights the potential for important
short-term emissions reduction benefits, since methane decays quickly (it has a 12 year lifetime) and
thus has its maximum warming impact well before 100 years is reached.
WARM and Composting
As of August 2010, a new version of WARM includes a more comprehensive analysis of composting
yard and food waste than it has in the past. First, the calculation of landfill emissions from organics is
based on a first-order decay rate to better measure when emissions are generated. Previous versions
of the model only calculated the lifetime methane yield. In addition, landfill gas capture systems is
modeled with a time element, assuming systems are phased in at landfills. With these two new
elements, the model is able to estimate the amount of methane being generated at a particular time
and the amount of methane being captured at that time. This new calculation methodology most
affects food waste and grass.
Reducing Greenhouse Gas Emissions through Recycling and Composting 28
-------
The emission factors for branches, which degrade at a very slow rate, changed very little. The new
emission factor takes into account the higher soil carbon sequestration capacity for compost-
improved soil as well as the GHG emissions involved in composting machinery and transportation.
However, the updated model still does not include an emission factor for other compostable
materials, like non-recyclable paper. WARM also does not include GHG emissions or emissions
reductions associated with other co-benefits associated with the use of compost, such as water
conservation and changes in fertilizer use. Finally, WARM does not differentiate between the
potential for varying emissions from compost sites themselves as a function of technology (e.g.,
anaerobic vs. aerobic composting, or centralized vs. home composting).
WARM does not currently break emissions and emissions reductions into the years in which they
actually occur. Rather, WARM rolls all future emissions and emissions reductions into a single
number. While appropriate for comparing program options against each other, this limits WARM's
usefulness in inventories, since most other emissions are reported in the years in which they actually
occur. Organic materials (e.g. cardboard, paper, lumber) have avoided emissions associated with
source reduction and recycling that are time-sensitive.
Forest carbon sequestration: When paper is recycled, fewer trees are cut down. This carbon
sequestration reduces the net emissions associated with paper source reduction and recycling. The
reductions occur over decades, since every year following the actual recycling or source reduction
event, over their lifetime, these trees absorb carbon as they continue to grow.
Avoided landfill emissions: When paper is recycled, less of it goes into the landfill. Landfill methane
emissions are reduced, and these avoided emissions reduce the net emissions associated with paper
source reduction and recycling. These reductions occur over decades, since decay in the landfill
occurs over decades. The same is true for diversion of other putrescible wastes, such as food waste
composting.
WARM treats international production - both of virgin and recycled materials - as if production in
other countries have the same emissions factors (emissions per ton) as domestic production. Given
the international flow of products and recycled feedstocks, and the potential for significant regional
differences in emissions based on regional fuel mixes and technology patterns, this is a potential
limitation. This is particularly acute in the forest carbon sequestration element of WARM (for paper
recycling and source reduction), which is based entirely on modeling of forest management practices
in the domestic US. Forest management practices, and the associated carbon benefits/impacts of
reducing use of wood, likely vary widely between the US and some other areas of the world, including
areas that would supply virgin fiber to foreign mills were it not for their use of wastepaper exported
from the US.
Reducing Greenhouse Gas Emissions through Recycling and Composting 29
------- |