Congressional Budget OfficeNonpartisan Analysis for the U.S.CongressEmissions ofGreenhouse Gases inthe Agriculture SectorAt a GlanceThe agriculture sector emits greenhouse gases(GHGs)through its two main activities:producingcrops and managing livestock (including poultry).The sector is the nation's leading source ofemissions of GHGs other than carbon dioxide(CO,).The accumulation of GHGs in the atmospherecontributes 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 invarious sectors of the economy.It provides an overview of the main components of GHG emissionsfrom 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 theircapacity to trap atmospheric heat),including nearly half of the nation's total non-CO,emissions.Agricultural GHG emissions are mainly nitrous oxide and methane,which,per tonemitted,are much more potent than CO,in trapping atmospheric heat.Agriculture accounts fornearly 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 comefrom livestock.The sector's nitrous oxide emissions mainly come from fertilizers used to producecrops.Most of its methane emissions are from livestock operations,particularly from collectingand storing manure and from the digestive emissions of cattle.Agricultural GHG emissions have increased much less than agricultural production has in thepast 25 years.Those emissions have increased by about 7 percent since 1990(mostly from greaterlivestock emissions),whereas milk production and harvests of field crops have both increasedby 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 GHGemissions 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 byabout a quarter of a percent each year.Actual GHG emissions will vary depending on whetherfuture demand for U.S.agricultural production is greater or less than projected and on the pace atwhich agricultural technologies that would reduce emissions are developed and adopted.www.cbo.gov/publication/61467