The ecological impact of food

Food, and particularly the meat we consume, is a major source of greenhouse gas emissions. There are two main reasons for this. First, we need a lot of land to feed our animals (by growing cereals) and to let them graze. Agriculture is responsible for about 80% of global deforestation. This deforestation releases CO₂ (through burning), destroys the natural habitat of many species, and deprives us of a major carbon sink. Secondly, ruminants—especially cows—emit large amounts of CO₂-equivalent gases through their burps and manure. This is why animal proteins generate far more greenhouse gas emissions than plant proteins, even when produced locally. For example, for every 100 g of protein, beef releases almost 50 kg of CO₂-equivalent gases, compared with less than 3 kg for cereals.

Greenhouse gas emissions per 100g of protein

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Greenhouse gas emissions are measured in kilograms of carbon dioxide equivalent (kg CO2eq) per 100g of protein. This measurement takes into account most greenhouse gases (CH4, N2O, O3, etc.). As these gases have different global warming potentials, for simplicity’s sake, the measurements are converted and expressed in kg CO2 equivalent.

Animal proteins generate more greenhouse gas emissions than plant proteins, even in short supply chains

eq 49,89kg CO₂

Beef

eq 5,98kg CO₂

Farmed fish

eq 0,26kg CO₂

Hazelnuts

Note : The data represents global average greenhouse gas emissions from food products based on a comprehensive meta-analysis of food production covering 38,700 commercially viable farms in 119 countries.
Source : Poole, J., & Nemecek, T. (2018). Additional calculations by Our World in Data.