Greenhouse gas inventories from animal agriculture for the United States

The 2005 EPA greenhouse gas emissions inventory estimates that in 2003 total U.S. greenhouse gases were 6900.2 Tg CO 2 Eq. of which 486.4 Tg CO2 Eq. was from agriculture . The contribution of greenhouse gases from agriculture was estimated to be 7.0% of the total emissions. Using the same methodology, EPA estimated that 1990 contributions from agriculture were 418.4 Tg CO 2 Eq. In EPA estimates, contributors to the inventory include methane from enteric fermentation and manure management, and N 2 O from manure management and agricultural soils management. The category agricultural soils management includes N 2 O emissions from pasture, range and paddock distribution, synthetic fertilizer use, sewage sludge application, and some other cropping practices. Other contributors to the agriculture sector include livestock facility fuel and power associated emissions, as well as fuel-CO 2 and N 2 O from growth and processing of the crops consumed by livestock. To date, these other contributions are not separately identified by economic sector in any available U.S. inventory. Adding the categories currently unaccounted for into the agricultural inventory would be expected to increase the total from 486.4 to approximately 670 Tg CO 2 Eq. and the livestock sector contribution could reach approximately 380 Tg/year CO 2 Eq.