"The agriculture sector is a source of greenhouse gas (GHG) emissions, which many scientists agree are contributing to observed climate change. Agriculture is also a 'sink' for sequestering carbon, which might offset GHG emissions by capturing and storing carbon in agricultural soils. The two key types of GHG emissions associated with agricultural activities are methane (CH4) and nitrous oxide (N2O). Agricultural sources of CH4 emissions mostly occur as part of the natural digestive process of animals and manure management at livestock operations; sources of N2O emissions are associated with soil management and fertilizer use on croplands. This report describes these emissions on a carbon-equivalent basis to illustrate agriculture's contribution to total national GHG emissions and to contrast emissions against estimates of sequestered carbon. […] The 110th Congress is considering a range of climate change policy options, including mandatory GHG emission reduction programs. The current legislative proposals would not require emission reductions in the agriculture and forestry sectors. However, some of the GHG emission reduction programs would allow the agriculture and forestry sectors to generate carbon offsets, whereby participating farmers and landowners could generate (and sell) carbon offsets and credits associated with carbon capture and storage, emissions reductions, and/or other implemented environmental improvements. Also, as part of the pending omnibus farm bill debate, there are provisions in the House and Senate versions of the bill (H.R. 2419) that could expand the scope of existing farmland conservation programs that contribute to emissions reductions and carbon storage in agricultural activities."
CRS Report for Congress, RL33898