Abstract
BACKGROUND: The farm animal sector is the single largest anthropogenic user of land, contributing to many environmental problems, including global warming and climate change. OBJECTIVES: The aim of this study was to synthesize and expand upon existing data on the contribution of farm animal production to climate change. METHODS: We analyzed the scientific literature on farm animal production and documented greenhouse gas (GHG) emissions, as well as various mitigation strategies. DISCUSSIONS: An analysis of meat, egg, and milk production encompasses not only the direct rearing and slaughtering of animals, but also grain and fertilizer production for animal feed, waste storage and disposal, water use, and energy expenditures on farms and in transporting feed and finished animal products, among other key impacts of the production process as a whole. CONCLUSIONS: Immediate and far-reaching changes in current animal agriculture practices and consumption patterns are both critical and timely if GHGs from the farm animal sector are to be mitigated.