Table 20. U.S. Methane Emissions from the Solid Waste of Domesticated Animals, 1990-1998
(Thousand Metric Tons of Methane)

Type of Animal 1990 1991 1992 1993 1994 1995 1996 1997 P1998
Cattle 1,163 1,184 1,196 1,208 1,230 1,232 1,216 1,212 1,216
  Beef Cattle 249 264 271 278 288 287 277 276 274
  Dairy Cattle 914 920 924 930 943 945 939 936 943
Swine 1,234 1,306 1,312 1,308 1,343 1,338 1,259 1,360 1,392
  Market Swine 861 912 924 918 958 952 895 981 1,026
  Breeding Swine 373 394 388 390 385 387 364 379 366
Poultry 157 161 167 179 184 189 193 197 203
  Caged Layers 83 84 86 88 89 89 91 92 97
  Broilers 73 77 81 91 95 100 102 105 107
Other Animals 18 17 17 17 17 17 17 17 18
  Sheep 5 5 5 5 4 4 4 4 3
  Goats 1 1 1 1 1 1 1 1 1
  Horses 12 11 11 11 12 12 13 13 13
Total 2,571 2,669 2,692 2,712 2,774 2,776 2,684 2,786 2,829
P = preliminary data.
Notes: Data in this table are revised from the data contained in the previous EIA report, Emissions of Greenhouse Gases in the United States 1997, DOE/EIA-0573(97) (Washington, DC, October 1998). Totals may not equal sum of components due to independent rounding.
Sources: Population data for horses and goats extrapolated from U.S. Department of Commerce, Bureau of the Census, Census of Agriculture, 1982, 1987, and 1992. Population data for all other animals from U.S. Department of Agriculture, National Agricultural Statistics Service, Livestock, Dairy and Poultry Branch. Typical animal sizes from U.S. Environmental Protection Agency, Office of Air and Radiation, Anthropogenic Methane Emissions in the United States: Estimates for 1990, Report to Congress (Washington, DC, April 1993), p. 6-8. Cattle sizes adjusted by annual slaughter weight from U.S. Department of Agriculture, National Agricultural Statistics Service, Livestock, Dairy and Poultry Branch. Maximum methane production, and waste management systems used from L.M. Safley, M.E. Casada, et al., Global Methane Emissions from Livestock and Poultry Manure (Washington, DC: U.S. Environmental Protection Agency, February 1992), pp. 24-27, and U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-1994, EPA-230-496-006 (Washington, DC, November 1995), Appendix D. General methane conversion factors from Intergovernmental Panel on Climate Change, Greenhouse Gas Inventory Reference Manual: Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 3 (Paris, France, 1997), p. 4.25, web site www.iea.org/ipcc/invs6.htm. State methane conversion factors for dairy cattle from U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-1997, EPA-236-R-99-003 (Washington, DC, April 1999), pp. 162-164, web site www.epa.gov/globalwarming/inventory/1999-inv.html.

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