Greenhouse gas emissions by the livestock sector could be cut by as much as 30% through the wider use of existing best practices and technologies, according to a new study released Sept. 26 by the U.N. Food & Agriculture Organization (FAO).
The report, "Tackling Climate Change Through Livestock: A Global Assessment of Emissions & Mitigation Opportunities," represents the most comprehensive estimate made to-date of livestock's contribution to global warming — as well as the sector's potential to help tackle the problem.
The report can be downloaded at www.fao.org/docrep/018/i3437e/i3437e.pdf.
All told, FAO said greenhouse gas (GHG) emissions associated with livestock supply chains add up to 7.1 gigatonnes (GT) of carbon dioxide equivalent per year — or 14.5% of all human-caused GHG releases.
The main sources of emissions are: feed production and processing (45% of the total), outputs of GHG during digestion by cows (39%) and manure decomposition (10%). The remainder is attributable to the processing and transportation of animal products, according to FAO.
To arrive at its estimates, FAO conducted a detailed analysis of GHG emissions at multiple stages of various livestock supply chains, including the production and transport of animal feed, on-farm energy use, emissions from animal digestion and manure decay, as well as post-slaughter transport, refrigeration and packaging of animal products.
Substantial emission reductions can be achieved across all species, systems and regions, FAO's report argues, with the greatest potential for cuts found in low productivity ruminant livestock systems in South Asia, Latin America and Africa.
However, in developed countries — where emission intensities are relatively low but the overall volume of production, and therefore, emissions are high — even small decreases in intensity could still add up to significant gains. This is the case for example for dairy farming in Europe and North America and for pork raising in East Asia.