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Livestock and greenhouse gas emissions

Broadening Horizons N°5, January 2014

By Harinder Makkar, FAO, Rome

► Total emissions from global livestock is 7.1 Gigatonnes of CO2-equiv per year, representing 14.5% of all anthropogenic greenhouse gas emission (GHG) emissions.

► Feed production and processing (this includes land use change) and enteric fermentation from ruminants – representing 45 and 39% of total emissions, respectively – are the two main sources of emission. Manure storage and processing represent 10%, and the remaining emissions are sourced to the processing and transportation of animal products.

► Among the livestock species most emissions is from cattle, representing about 65% of the livestock sector’s emissions.

► Spanning over all species and activities, the consumption of fossil fuel along supply chains accounts for about 20% of the livestock sector’s emissions.

► On a commodity-basis, beef and cattle milk are responsible for the most emissions, contributing 41 and 20% respectively of the overall GHG outputs from the livestock sector (this figure excludes emissions from cow manure and cattle used as drought). They are followed by pig meat, (9% of emissions), buffalo milk and meat (8%), chicken meat and eggs (8%), and small ruminant milk and meat (6%). The remainder is attributable to other poultry species and non-edible products.

► Emission intensities (i.e. emissions as CO2 equivalent per unit of product) are highest for beef (almost 300 kg CO2-equivalent per kg of protein produced), followed by meat and milk from small ruminants (165 and 112 kg CO2-equivalent per kg protein produced respectively). Cow milk, chicken products and pork have lover global average emission intensities (< 100 CO2- equivalent/kg protein produced).

► From ruminant production, enteric emissions and feed production (including manure deposition on pasture) dominate the emissions. In poultry supply chain the feed supply represents the bulk of emissions, followed by energy consumption, while in pig production, the bulk of emissions are related to the feed supply and manure storage in processing.

► About 44% of livestock emissions are in the form of methane (CH4). The remainder is shared between nitrous dioxide (N2O, 29%) and carbon dioxide (CO2, 27%). This means that livestock supply chains emit:

  • 2 Gt CO2-equivalent of CO2 per annum, or 5% of anthropogenic CO2 emissions (IPCC, 2007)
  • 3.1 Gt CO2-equivalent of CH4 per annum, or 44% of anthropogenic CH4 emissions (IPCC, 2007)
  • 2 Gt CO2-equivalent of N2O per annum, or 53% of anthropogenic N2O emissions (IPCC, 2007)

Source: FAO http://www.fao.org/docrep/018/i3437e/i3437e.pdf

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