EPA's State and Local Capacity Building Branch partners with states to develop greenhouse gas (GHG) inventories and action plans. Forty-one states and Puerto Rico have completed inventories. Each inventory identifies the major sources of GHG emissions and creates a baseline upon which reduction strategies are based. States play a critical role in reducing GHG emissions; many states have developed State Action Plans that draw heavily on the information in their inventories.
The inventories present annual emissions of GHGs 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 (MMTCDE); both units provide a common metric across the various gases, and normalize their influence on warming as expressed by their global warming potential. The methods on which the inventories are based generally estimate GHG emissions as a function of (a) activity data (e.g., electricity usage, cement production, fertilizer consumption, etc.) and (b) activity- and gas-specific emission factors. The EPA State and Local Capacity Building Branch has been instrumental in developing methods for state GHG inventories.
The inventory method has changed since EPA published the first guidance on developing state inventories of greenhouse gas (GHG) emissions in 1992. In fact, EPA has revised its guidance four times to incorporate changes in international inventory guidance, US inventory methods, and input from a panel of state representatives. The most recent guidance can be found in Volume VIII of the Emission Inventory Improvement Program (EIIP) Guidelines, entitled Estimating Greenhouse Gas Emissions.
EPA's online state inventory summaries attempt to reflect the most recent guidance by recalculating some of the emission estimates supplied by the states. Thus, GHG emissions reported in these summaries may differ from emission estimates reported in the states' inventory document. We have explained the difference between EPA and state estimates (22KB pdf).
Brief summaries of many state inventories are available at this site. In some cases, we also provide links to full text at state-sponsored websites. We have also created an overview of state GHG emissions by sector, reflecting the adjustments made by EPA (46KB pdf). To view inventory summaries and full text of state inventories, click on a state shaded orange in the map below or select a state from the “State GHG Inventories” drop-down menu. There is currently no information available for states shaded blue.
