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- State and Local Emissions
- Energy CO2 Emissions by State
- State Greenhouse Gas Inventories
- Resources for Inventory Development
State Greenhouse Gas Inventories
Related Links
EPA supports state efforts to develop greenhouse gas inventories by providing inventory guidance, tools and technical assistance. Forty-four states and Puerto Rico have completed inventories as of March 2008. States use their inventories to understand their emissions sources, develop State Climate Change Action Plans, and implement policies and programs to reduce greenhouse gas emissions.
The “GHG Inventory” map located on the “State Planning and Measurement” site identifies which states have completed a greenhouse gas inventory. Brief inventory summaries for the recent or updated inventories as well as links to full text of the inventories at state-sponsored Web sites are available by clicking on each state. EPA also maintains a list of all completed state inventories.
The inventories present annual emissions of greenhouse gases by sector (e.g., energy, agriculture, waste), by source (e.g., transportation emissions, manure management) and by gas (e.g., carbon dioxide, methane). State totals are reported in million metric tons of carbon equivalent (MMTCE) or million metric tons of carbon dioxide equivalent (MMTCO2E); both units provide a common metric across the various gases, and normalize their influence on warming as expressed by their global warming potential (PDF, 8 pp., 441 KB, About PDF).
The methods on which the inventories are based generally estimate greenhouse
gas emissions as a function of (a) activity data (e.g., coal consumption,
cement production, fertilizer consumption, etc.) and (b) activity- and
gas-specific emission factors. EPA has been instrumental in developing methods
for state GHG inventories that are consistent with those used for the United
States national inventory, and with the Intergovernmental
Panel on Climate Change (IPCC) Guidelines 
.
EPA's online state inventory summaries reflect inventory estimates supplied
by the states. In some cases, state emission estimates are significantly
different from what would be calculated using EPA tools and guidance and
these cases are noted within specific state summaries.