Below graph shows the greenhouse gas (GHG) emissions per kilogram of food product from 29 different food products, researched by One World in Data. In this study, data was taken from the largest meta-analysis of global food systems to date, published in Science by Joseph Poore and Thomas Nemecek (2018), who collected data across more than 38,000 commercial farms in 119 countries.
CO2 is not the only the critical source of GHG emission; agriculture is a large source of the greenhouse gases methane and nitrous oxide, therefore to capture all GHG emissions from food production, in this study, researchers has expressed them in kilograms of ‘carbon dioxide equivalents’.
Insights from this study shows that overall, animal-based foods tend to have a higher footprint than plant-based. Producing a kilogram of beef emits 60 kilograms of greenhouse gases (CO2-equivalents). Lamb and cheese both emit more than 20 kilograms CO2-equivalents per kilogram. Poultry and pork have lower footprints but are still higher than most plant-based foods, at 6 and 7 kg CO2-equivalents.
For most foods, most GHG emissions result from land use change (shown in green), and from processes at the farm stage (brown). Farm-stage emissions include processes such as the application of fertilizers – both organic (“manure management”) and synthetic; and enteric fermentation (the production of methane in the stomachs of cattle). Combined, land use and farm-stage emissions account for more than 80% of the footprint for most foods.