Agriculture Sector Emissions

On this page:

• Sources of Agriculture Sector Emissions
• Agriculture Sector Emissions Trends
• Reducing Emissions from Agriculture

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Sources of Agriculture Sector Emissions

Agricultural activities — crop and livestock production — contribute to emissions in a variety of ways:

• Various management practices on agricultural soils can lead to increased availability of nitrogen in the soil and result in emissions of nitrous oxide (N₂O). Specific activities that contribute to N₂O emissions from agricultural lands include the application of synthetic and organic fertilizers, the growth of nitrogen-fixing crops, the drainage of organic soils, and irrigation practices. Management of agricultural soils accounts for just over half of the greenhouse gas emissions from the Agriculture sector. Management of croplands and grasslands can also lead to emissions or sequestration of carbon dioxide (CO₂). These emissions and removals are included under the Land Use, Land-Use Change, and Forestry sector.
• Livestock, especially ruminants such as cattle, produce methane (CH₄) as part of their normal digestive processes. This process is called enteric fermentation, and it represents over a quarter of the greenhouse gas emissions from the Agriculture sector.
• The way in which manure from livestock is managed also contributes to CH₄ and N₂O emissions. Different manure treatment and storage methods affect how much of these greenhouse gases are produced. Manure management accounts for about 14% of the total greenhouse gas emissions from the Agriculture sector in the United States.
• Smaller sources of agricultural emissions include CO₂ from liming and urea application, CH₄ from rice cultivation, and burning crop residues, which produces CH₄ and N₂O.

More information about emissions from agriculture can be found in the agriculture chapter in the Inventory of U.S. Greenhouse Gas Emissions and Sinks.

Agriculture Sector Emissions Trends

• In 2022, direct greenhouse gas emissions from the agriculture sector accounted for 9.4% of total U.S. greenhouse gas emissions.
• Greenhouse gas emissions from agriculture have increased by 8% since 1990. Agricultural soil management activities, such as application of synthetic and organic fertilizers, deposition of livestock manure, and growing nitrogen fixing plants, were the largest contributors to U.S. N₂O emissions in 2022, accounting for 75% of total N₂O emissions. Emissions from other agricultural sources have generally remained flat or changed by a relatively small amount since 1990.

Reducing Emissions from Agriculture

The table shown below provides examples of opportunities to reduce emissions from agriculture. For a more comprehensive list of options and a detailed assessment of how each option affects different gases, see Chapter 7 of the Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.

Examples of Reduction Opportunities for the Agriculture Sector

Type	How Emissions Are Reduced	Examples
Land and Crop Management	Adjusting the methods for managing land and growing crops.	Fertilizing crops with the appropriate amount of nitrogen required for optimal crop production, since over-application of nitrogen can lead to higher nitrous oxide emissions without enhancing crop production. Draining water from wetland rice soils during the growing season to reduce methane emissions.
Livestock Management	Adjusting feeding practices and other management methods to reduce the amount of methane resulting from enteric fermentation.	Improving pasture quality to increase animal productivity, which can reduce the amount of methane emitted per unit of animal product. Also, increased productivity in livestock can be introduced through improved breeding practices.
Manure Management	Controlling the way in which manure decomposes to reduce nitrous oxide and methane emissions. Capturing methane from manure decomposition to produce renewable energy.	Handling manure as a solid or depositing it on pasture rather than storing it in a liquid-based system such as a lagoon would likely reduce methane emissions but may increase nitrous oxide emissions. Storing manure in anaerobic lagoons to maximize methane production and then capturing the methane to use as an energy substitute for fossil fuels. For more information on capturing methane from manure management systems, see EPA's AgSTAR Program, a voluntary outreach and education program that promotes recovery and use of methane from animal manure.