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Please see EPA's Climate Change site for current information on climate change and global warming. EPA no longer updates EPA's Global Warming Site, but is maintaining this archive for historical purposes. Thank you for visiting the archive of EPA's Global Warming Site.
Comparison of EPA State Inventories and the Inventory of U.S. Greenhouse Gas Emissions and Sinks
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The estimates of CO2 from fossil fuel combustion found in the Inventory of U.S. Greenhouse Gases and Sinks differs slightly from the sums of the State Inventory emissions estimates. The methodological differences between the two inventories are discussed below.
- U.S. Territory CO2 emissions are included in the U.S. Inventory’s national emissions totals, but not in the State Inventory national totals.
- Emissions from fuels used for international transport (bunker fuels) are not included in the U.S. Inventory’s national totals; however, they may be included in the State Inventory emissions totals. Bunker fuel data is not provided from the EIA on a state-by-state basis, so this subtraction can only be made at the national level. In some cases, individual states have data on bunker fuel consumption, and have used this data in their state-authored inventories.
- For certain fuel types, such as coal and LPG, the U.S. Inventory uses carbon coefficients which change annually. For simplicity and consistency, this is not part of EIIP Workbook and is not used in calculating emissions for the State Inventories.
- Small adjustments are made to certain fuel categories in the U.S. Inventory to reduce the chances of double counting. Examples include subtractions made from motor gasoline to account for ethanol, subtractions made from industrial coal to account for synthetic natural gas production, and subtractions made from natural gas to account for refined landfill methane used for fuel. Although some of this data is available on a state-by-state basis and could be included in the State Inventory method, the absolute change in emissions would be very small. Also, it is currently not included in EIIP Workbook.
- The US Inventory now reports emissions from fuels used for non-energy uses (NEU) separately from fuel combustion estimates. The State Inventory Tool still uses the accepted method of subtracting carbon stored from total fossil fuel carbon, which results in including NEU emissions in the estimates of CO2 from fossil fuel combustion.
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