Environment: Quantifying food-related global greenhouse gas emissions

Global food production is responsible for greenhouse gas (GHG) emissions equivalent to 17,318 teragrams (17.318 billion metric tonnes) of CO2 per year — 57% of which corresponds to the production of animal-based foods and 29% to plant-based foods, estimates a study published in Nature Food. This calculation — based on data from over 200 countries circa 2010 — includes GHGs associated with animal feed, transportation and international trade, among other factors.

The adoption of plant-based diets has been widely recognized as an effective strategy to mitigate climate change, however, the exact potential contribution of such dietary shifts has yet to be calculated. Despite previous efforts to assess GHG emissions from agriculture, forestry and land use, food sector data are sparse, spatially inexplicit and methodologically inconsistent across agricultural sub-sectors.

By developing a consistent, unified data-modelling framework, Atul Jain and colleagues were able to build an open-access database to allow for the estimation of global GHG emissions (CO2, methane and nitrous oxide) from plant- and animal-based human food. This database includes a wide range of farming practices, agricultural products — totaling 171 crops and 16 animal products — and data from more than 200 countries around the year 2010. The team estimates that global food production was responsible for GHG emissions equivalent to 17,318 teragrams of CO2 per year, of which 57% corresponds to the production of animal-based food, 29% to plant-based foods and 14% to other utilizations, such as rubber and cotton. Farmland management and land-use change represented major estimated shares of the total GHG emissions (38% and 29%, respectively), and rice and beef were the largest contributing plant- and animal-based commodities (12% and 25%, respectively). South and Southeast Asia and South America were the largest emitters of production-based GHGs.