The footprint of what we eat
Food accounts for roughly a quarter of global greenhouse gas emissions. The biggest differences come from what we eat, not where it comes from. Ruminant meat is by far the most carbon-intensive, because cattle and sheep need a lot of land and feed and produce methane.
Emissions per kilogram of food
These global averages come from a large 2018 study by Poore and Nemecek, covering about 38,000 farms, as published by Our World in Data:
| Food | kg CO₂e per kg |
|---|---|
| Beef (beef herd) | 99.5 |
| Lamb and mutton | 39.7 |
| Beef (dairy herd) | 33.3 |
| Shrimp (farmed) | 26.9 |
| Cheese | 23.9 |
| Fish (farmed) | 13.6 |
| Pork | 12.3 |
| Poultry | 9.9 |
| Eggs | 4.7 |
| Rice | 4.5 |
| Tofu | 3.2 |
| Milk (per liter) | 3.2 |
| Peas | 1.0 |
| Potatoes | 0.5 |
Worked example
You eat 1.5 lb (0.68 kg) of beef a week and are thinking of replacing it with chicken.
- Weekly emissions: 0.68 × 99.5 = 67.7 kg CO₂e.
- Yearly emissions: 67.7 × 52 = 3,520 kg, about 3.5 tonnes.
- With poultry instead: 0.68 × 9.9 × 52 = 350 kg.
- Savings: 3,170 kg CO₂e per year, a 90% cut.
- Your current beef emissions equal driving a gas car about 8,800 miles.
What matters most
- Type of food: swapping beef for poultry, pork, beans or tofu has the largest effect.
- Portion size: halving red meat portions halves their footprint.
- Waste: about a third of food is lost or wasted; buying what you eat avoids emissions for nothing.
- Transport: usually under 10% of a food’s footprint, except for air-freighted produce such as some berries and asparagus out of season.
- Packaging: generally a small share, though it matters for waste.
Limits
Values vary a lot between farms: the most carbon-intensive beef can emit 10 times more than the least. Grass-fed, organic or local labels do not always mean lower emissions. Use the figures to compare foods, not to compute an exact personal footprint.