Meat Carbon Footprint Calculator

Life-cycle assessment (LCA) of food products traces emissions from farm to fork. For beef, the largest sources are enteric fermentation (methane from cow digestion, ~40%), feed production (~35%, including deforestation for pasture and soy), and manure management (~10%). Methane (CH4) is a particularly potent greenhouse gas with a global warming potential 28 times that of CO2 over 100 years. Lamb has the highest emission factor per kilogram of any common meat, primarily because sheep are ruminants like cattle but have lower feed conversion efficiency (more feed per kilogram of meat). Pork and chicken are monogastric animals (single-chambered stomach) and do not produce significant enteric methane, giving them much lower emission factors. Farmed fish emissions come mainly from feed production and energy use at aquaculture facilities. Wild-caught fish emissions are dominated by fuel consumption for fishing vessels. Both are significantly lower than ruminant meat but vary widely by species and method. Plant-based proteins like tofu, lentils, and beans have the lowest emission factors because they require no animal feed conversion step, produce no enteric methane, and fix nitrogen naturally (reducing fertiliser needs for legumes). Replacing beef with lentils for one meal can reduce emissions by over 90%. Emission factors vary by region, farming system, and methodology. Grass-fed beef in some studies shows lower emissions than grain-fed, while other studies show the opposite depending on land-use change assumptions. The values in this calculator are global averages from peer-reviewed meta-analyses and should be treated as indicative rather than exact. Beyond carbon, meat production has major impacts on water use (15,000 litres per kg of beef), land use (70% of agricultural land is used for livestock), and biodiversity loss through habitat conversion.