Emissions of Greenhouse Gases in the Agriculture Sector

The agriculture sector emits greenhouse gases (GHGs) through its two main activities: producing crops and managing livestock (including poultry). The sector is the nation's leading source of emissions of GHGs other than carbon dioxide (CO₂). The accumulation of GHGs in the atmosphere contributes to climate change, which affects the economy and the federal budget.

This is the fourth in a series of reports from the Congressional Budget Office on GHG emissions in various sectors of the economy. It provides an overview of the main components of GHG emissions from agriculture, recent trends in those emissions, and projections of future emissions.

• Agriculture accounts for about 10 percent of total U.S. GHG emissions (measured by their capacity to trap atmospheric heat), including nearly half of the nation's total non-CO₂ emissions. Agricultural GHG emissions are mainly nitrous oxide and methane, which, per ton emitted, are much more potent than CO₂ in trapping atmospheric heat. Agriculture accounts for nearly all U.S. emissions of nitrous oxide and almost half of emitted methane.
• About half of agricultural GHG emissions are from crop production; nearly all of the rest come from livestock. The sector's nitrous oxide emissions mainly come from fertilizers used to produce crops. Most of its methane emissions are from livestock operations, particularly from collecting and storing manure and from the digestive emissions of cattle.
• Agricultural GHG emissions have increased much less than agricultural production has in the past 25 years. Those emissions have increased by about 7 percent since 1990 (mostly from greater livestock emissions), whereas milk production and harvests of field crops have both increased by more than 50 percent, on average, and meat production has increased by about 75 percent. The much larger increase in agricultural production compared with the rise in the sector's GHG emissions can be attributed to advances in agricultural technologies and in livestock breeding, nutrition, and health.
• CBO projects that in the coming decades, GHG emissions from agriculture will increase by about a quarter of a percent each year. Actual GHG emissions will vary depending on whether future demand for U.S. agricultural production is greater or less than projected and on the pace at which agricultural technologies that would reduce emissions are developed and adopted.