State and Local
Climate and Energy Program
From Inventory to Action:
Putting Greenhouse Gas
Inventories to Work
What are the uses of inventory results?
Developing an inventory is typically the first step toward setting a state or local emissions goal, but
inventory results have a variety of other important uses. In some ways, having an inventory is like having
a GPS unit in your car: it shows you where you are, how to get to where you want to go, and how far
along the path you've progressed. States and localities use greenhouse gas inventories to do the following:
• Identify sources of emissions, their current magnitude, and their rate of growth. An inventory can reveal
which sources require priority attention and which are too small to effectively matter.
• Establish a foundation for projecting future emissions.
• Provide a basis for emissions goals and a benchmark for progress toward achieving them.
• Evaluate the effects of proposed emissions reduction policy options.
Note that emissions inventories involve a process of continuous improvement: as methodologies are
refined and more reliable or comprehensive sources of data are developed, states and localities can
improve the accuracy of their inventories and projections.
Key steps and issues in setting emissions goals
Some of the choices and decisions below will be determined in part by inventory results; in all cases the
results of inventories (and projections based on them) will factor into the decision-making process.
• Scope: States and localities need to decide whether they will set goals for all six basic greenhouse gases
or a subset of them (such as carbon dioxide, methane, and nitrous oxide). Goals may be set for the entire
economy of a jurisdiction, a subset of the economy, or particular sectors.
• Time frame: Emissions goals may be short-term (e.g., two to five years out), mid-term (e.g., 20-30
years), or long-term (e.g., 40-50 years). The goals' time frame will influence the range of actions and
policy options used to achieve them. A state or locality may set a long-term goal but also have short-
term targets that serve as incremental steps toward that goal. This approach may allow you to test and
demonstrate the viability of a range of policy options for reducing emissions while working toward longer-
term goals.
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California GHG Inventory Forecast
Last updated: June 26, 2008
600
500
S 400
300
= 200
100
1990
Base year: The choice of a base year from which to
compare emission reduction goals is very important,
although this may be limited by data availability.
Ideally the base year should be "typical," in the sense
that emissions during that year were not influenced
by unusual conditions such as extremely high or low
economic growth, abnormal weather, or other outliers.
Criteria: States and localities have a range of criteria to
choose from in setting their emissions goals. A goal may
be based on a scientific recommendation, such as aiming
to reduce emissions by 80 percent below 1990 levels
by 2050 in order to stabilize atmospheric concentrations
at levels that avoid dangerous impacts. Alternatively,
goals and baseline years may be established to be
consistent with existing targets, such as those of the
U.S. Council of Mayors' Climate Protection Agreement
or another established international, national, or regional
agreement. Goals also may be designed to be pragmatic,
based on technical and economic feasibility; this is often
the case for short-term goals.
EPA, state governments, and a variety of organizations
can provide support for efforts to set emissions goals and
develop policies to achieve them. For more information,
please visit the following EPA resources online:
Climate Change: State and Local Governments
http://www.epa.gov/climatechange/wycd/stateandlocalgov/index.html
Climate Change: State and Local Tools and Resources
http://www.epa.gov/climatechange/wycd/stateandlocalgov/tools resources.html
Clean Energy: Local Best Practices
http://www.epa.gov/cleanenergv/energy-programs/state-and-local/local-best-practices.html
Clean Energy: State Best Practices
http://www.epa.gov/cleanenergv/energy-programs/state-and-local/state-best-practices.html
Clean Energy: State and Local Tools and Resources
http://www.epa.gov/cleanenergv/energy-programs/state-and-local/tools.html
2002-2004
average
2020
Transportation
Electric Power
Commercial and Residential
Industrial
Recycling and Waste
High GWP
Agriculture
Forestry
California projected business-as-usual emissions (see graph)
from its inventory to assess what reductions would be
needed to meet 1990 emissions levels by 2020. Source: Draft
California 2020 Greenhouse Gas Emissions Forecast, 2008.
EPA-430-F-09-002 February 2009
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