Agriculture accounted for an estimated 10.6 percent of U.S. greenhouse gas emissions in 2021

Farming activities in the United States accounted for 10.6 percent of U.S. greenhouse gas emissions in 2021. From 2020 to 2021, agricultural greenhouse gas emissions remained nearly constant but decreased from 11.1 percent to 10.6 percent as a share of total U.S. emissions because of changes in other industries. 

The U.S. Environmental Protection Agency estimated that in 2021, agriculture emitted 312.6 MMT as nitrous oxide (N₂O), 278.4 MMT as methane (CH₄), 44.7 MMT as on-farm carbon dioxide (CO₂), and 35.7 MMT emitted indirectly through the electricity that the agricultural sector uses. Emissions include activities that emit nitrous oxide, such as fertilizer application and manure storage and management, and methane from enteric fermentation (a normal digestive process in animals). 

Of the common economic sectors in the United States defined by the Energy Information Administration, industry accounted for the largest portion of total greenhouse gas emissions (30.1 percent), followed by transportation, commercial, residential, agriculture, and U.S. territories (no specific consumption data can be attributed within the territories, so they are listed as a group). Total U.S. greenhouse gas emissions in 2021 were 2.3 percent lower than they were in 1990. This chart appears in the USDA, Economic Research Service topic page Climate Change.