The U.S. Environmental Protection Agency estimated that agriculture, including its electricity consumption, accounted for an estimated 10.6 percent of U.S. greenhouse gas (GHG) emissions in 2021. Globally, carbon dioxide emissions are the largest contributor to climate change. However, the emissions profile for agriculture differs from that of the overall economy. In agriculture, crop and livestock activities emit nitrous oxide and methane, mainly from fertilizer application, enteric fermentation (a normal digestive process in animals that produces methane), and manure storage and management. GHG emissions from U.S. agriculture have increased by approximately 6.9 percent since 1990, while total U.S. GHG emissions in 2021 were 2.3 percent lower than they were in 1990.
