Agriculture makes the greatest contribution to total food system emissions. It contributes 7,300 to 12,700 million metric tonnes of carbon dioxide equivalent (MtCO2e) per year—about 80 to 86 percent of food systems emissions and 14 to 24 percent of total global emissions.

Vermeulen et al., 2012

Data from Vermeulen, et al., 2012; US-EPA, 2011; and Stern, 2006

Extra facts

  • Food production and consumption contribute 19 to 29 percent of total greenhouse gas emissions—9,800 to 16,900 MtCO2e (million metric tonnes of carbon dioxide equivalent at 2008 levels) per year. This figure includes the full supply chain, including fertilizer manufacture, agriculture, processing, transport, retail, household food management and waste disposal.
  • Agriculture makes the greatest contribution to total food system emissions. It contributes 7,300 to 12,700 MtCO2e per year—equivalent to 80 to 86 percent of food systems emissions and 14 to 24 percent of total global emissions.
  • Deforestation and land use change account for 2,200 to 6,600 MtCO2e per year—30 to 50 percent of agricultural emissions and 4 to 14 percent of total global emissions.
  • Direct emissions from agriculture, through, for example, activities like managing soils, crops and livestock contribute 5,100 to 6,100 MtCO2e per year—50 to 70 percent of agricultural emissions and 10 to 12 percent of total global emissions.
  • The food chain, excluding agriculture, contributes 14 to 20 percent of food-related emissions and, at most, 5 percent of global emissions.
  • The proportion of emissions from portions of the food chain that take place after food leaves the farm (“post-farmgate”) is larger in high-income countries. For example, these activities make up some 50 percent of food system emissions in the United Kingdom (Garnett 2011). Middle-income countries will likely follow this trend in the future.
  • Fisheries and aquaculture are estimated to make only minor contributions to greenhouse gas emissions.
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Methods, caveats and issues

Methods

The figure for total global emissions from food systems is an estimate based on:

  • Global data on fertilizer manufacture from the direct agricultural emissions from Smith et al 2007;
  • Global data on direct emissions from US-EPA 2011;
  • Global data on deforestation and associated emissions from van der Werf et al 2009 and Blaser and Robledo (2007); and
  • Chinese data on the post-farmgate portions of the food chain from Chen and Zhang 2010, assuming that, as a large middle-income country, China is suitably representative of the global level.

Issues

The wide percentage ranges are associated with geographic variation and uncertainty.

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Sources

  • Vermeulen, SJ, Campbell BM, Ingram JSI. 2012. Climate change and food systems. Annual Review of Environment and Resources 37:195–222.
  • HM Treasury. 2006. The economics of climate change: the stern review. London: HM Treasury. (Available from http://webarchive.nationalarchives.gov.uk/+/http:/www.hm-treasury.gov.uk/sternreview_index.htm)
  • [US-EPA] United States Environmental Protection Agency. 2011. Global anthropogenic non-CO2 greenhouse gas emissions: 1990 – 2030 EPA 430-D-11-003. (Draft.)  Office of Atmospheric Programs, Climate Change Division. Washington, DC: U.S. Environmental Protection Agency. (Available from http://www.epa.gov/climatechange/EPAactivities/economics/nonco2projections.html)
  • Smith P, Martino D, Cai ZC, Gwary D, Janzen H, Kumar P,  McCarlg B, Ogleh S, O’Marai F, Ricej C, Scholesk B, Sirotenkol O, Howdenm M, McAllistere T, Pann G, Romanenkovo V, Schneiderp U, Towprayoonq S. 2007. Policy and technological constraints to implementation of greenhouse gas mitigation options in agriculture. Agriculture, Ecosystems and Environment 118:6–28.
  • Blaser J, Robledo C. 2007. Analysis on the mitigation potential in the forestry sector. Report for the UNFCCC Secretariat. Bern: Intercooperation.
  • Chen GQ, Zhang B. 2010. Greenhouse gas emissions in China 2007: inventory and input-output analysis. Energy Policy 38:6180–93.
  • van der Werf GR, Morton DC, DeFries RS, Olivier JGJ, Kasibhatla PS,  Jackson RB, Collatz GJ, Randerson JT. 2009. CO2 emissions from forest loss. Nature Geoscience 2:737–38. (Available from http://152.3.12.176/jackson/ng09.pdf)
  • Garnett T. 2011. Where are the best opportunities for reducing greenhouse gas emissions in the food system (including the food chain)? Food Policy 36:23–32.
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