Diet and carbon footprint
Food is roughly a fifth of a typical European or American footprint. Within food, animal protein dominates: red meat and dairy account for most of the emissions, plant foods almost none.
Annual diet footprint by pattern
UK cohort estimates from Scarborough et al. (2023, Nature Food) for average dietary patterns. Tonnes of CO2-equivalent per person per year, food production from farm to retail.
Heavy meat (>100 g/day)3.32 tCO2e/yr
Medium meat (50-100 g/day)2.42 tCO2e/yr
Low meat (<50 g/day)1.88 tCO2e/yr
Pescatarian1.66 tCO2e/yr
Vegetarian1.39 tCO2e/yr
Vegan1.05 tCO2e/yr
Going from heavy-meat to vegan saves ~2.3 tCO2e/year. That's comparable to skipping one transatlantic round-trip flight, or to a full year of careful driving on a 12,000 km/year petrol car.
CO2 per kilogram, by food
From Poore & Nemecek (2018, Science 360): farm-to-retail emissions per kilogram of product. The variation is enormous — beef is 200× more carbon-intensive than nuts.
| Food | kg CO2e per kg | Relative | Note |
|---|---|---|---|
| Beef | 60 | highest of any major food | |
| Lamb | 24 | ||
| Cheese | 21 | ||
| Pork | 7.6 | ||
| Chicken | 6.9 | ||
| Fish (farmed) | 5 | ||
| Eggs | 4.5 | ||
| Rice | 2.7 | methane from paddies | |
| Milk | 2.7 | per litre | |
| Tofu | 2 | ||
| Bread / pasta | 1.4 | ||
| Beans / lentils | 0.9 | ||
| Vegetables | 0.4 | average | |
| Fruits | 0.5 | average | |
| Nuts | 0.3 | low — net-positive land use |
What actually moves the diet number
- Beef and lamb first. These are 5–10× the emissions of chicken or pork per kilogram. Cutting beef in half drops a heavy-meat diet by ~25%.
- Dairy second. Cheese is surprisingly high (21 kg CO2e/kg). Halving cheese is comparable to halving chicken.
- Local and seasonal does little. Transport is typically under 10% of food emissions. Production matters far more than miles.
- Food waste compounds. A third of food produced is wasted. Buying less and eating leftovers is roughly equivalent to going from heavy meat to medium meat.
Sources
- Poore & Nemecek (2018), Science 360 — per-food emissions meta-analysis.
- Scarborough et al. (2023), Nature Food 4, 565–574 — per-capita diet emissions by dietary pattern.