FAO's Livestock's Long Shadow: Livestock's contribution to Climate Change
Summary of Livestock’s contribution to Climate Change: “Overall, livestock activities contribute an estimated 18% to total anthropogenic GHG emissions from five major sectors for GHG reporting: energy, industry, waste, land use, land use change, land use change and forestry (LULUCF) and agriculture.” p.112 “Considering the last two sectors only, livestock’s share is over 50%. For the agriculture sector alone, livestock constitute nearly 80% of all emissions.” p.112 Carbon Dioxide: “When deforestation for pasture and feedcrop land and pasture degradation are taken into account, livestock-related emissions of carbon dioxide are an important component of the global total (some 9 percent).” p.112 “The livestock food chain is becoming more fossil fuel intensive, which will increase carbon dioxide emissions from livestock production.” p.112 Methane: “Together, enteric fermentation and manure represent some 80 percent of agricultural methane emissions and about 35-40 percent of the total anthropogenic methane emissions.”p.112 “Methane emissions from animal manure, although much lower in absolute terms, are considerable and growing rapidly.” p.114 Nitrous Oxide “Livestock activities contribute substantially to the emission of nitrous oxide, the most potent of the three major greenhouse gases.” p.114 “They contribute almost two-thirds of all anthropogenic N2O emissions, and 75-80 percent of agricultural emissions. Current trends suggest that this level will substantially increase over the coming decades.” p.114 Ammonia “94 percent of [ammonia emissions] is produced by the agricultural sector. The livestock sector contributes about 68 percent of the agricultural share, mainly from deposited and applied manure.” Here is a google doc I have compiled with additional info: https://docs.google.com/document/d/1i_8w4x8vztdyn23kgPi5tO2MVGLE5HTVN5ST...
Source: Henning Steinfeld, "Livestock's Long Shadow: Environmental Issues and Options," Food and Agriculture Organization of the United Nations, Rome, 2006 available at:http://www.fao.org/docrep/010/a0701e/a0701e00.HTM [verified 4/17/14]