The environmental impact of meat and dairy: what the data shows in 2026

The 2018 Science paper by Joseph Poore and Thomas Nemecek — still the largest meta-analysis of food's environmental impact ever published — concluded that "a vegan diet is probably the single biggest way to reduce your impact on planet Earth." Seven years later, the data has only gotten stronger. Here is what's actually known.

Greenhouse gases

• Food systems are responsible for roughly 26–34% of global greenhouse gas emissions (Crippa et al., Nature Food 2021).
• Of that, ~57% comes from animal-based foods, despite providing only ~18% of calories and ~37% of protein consumed globally (Xu et al., Nature Food 2021).
• Per kilogram of protein: beef emits about 60 kg CO₂-equivalent; lamb ~24 kg; pork ~7 kg; chicken ~6 kg; tofu ~2 kg; lentils ~0.9 kg; peas ~0.4 kg.

Land use

Animal agriculture uses ~77% of the world's farmland (pasture plus feed-crop land) while producing only ~18% of calories. If the world adopted a plant-based diet, global farmland use could fall by an estimated 3.1 billion hectares— an area roughly the size of Africa — freeing land for rewilding, reforestation, and carbon drawdown (Poore & Nemecek, 2018).

Deforestation

Beef and animal-feed soy are the two largest drivers of tropical deforestation. Roughly 80% of Amazon deforestation is linked to cattle ranching, and a large share of soy grown in the Cerrado is fed to chickens, pigs, and farmed fish — not eaten directly by humans (TRASE, 2023). Most soy humans eat (tofu, tempeh, soy milk) comes from non-deforestation supply chains, often North American or European.

Water

• 1 kg of beef: ~15,400 L of water
• 1 kg of cheese: ~5,000 L
• 1 kg of chicken: ~4,300 L
• 1 kg of tofu: ~2,400 L
• 1 kg of lentils: ~1,250 L

(Source: Mekonnen & Hoekstra, Water Footprint Network, updated 2023.)

Fisheries and the ocean

About 34% of marine fish stocks are overfished and another 60% are fished at maximum sustainable limit (FAO SOFIA 2022). Industrial trawling destroys seabed habitat, and bycatch — non-target species caught and discarded — runs into the tens of billions of animals per year. Ghost gear (lost fishing nets) makes up an estimated 46% of the Great Pacific Garbage Patch by mass.

Biodiversity

Of the ~7,000 vertebrate species threatened with extinction whose drivers have been analyzed, agriculture is a threat to ~86% (Benton et al., Chatham House 2021). Livestock and crops grown to feed livestock are the dominant single pressure on terrestrial biodiversity.

What the IPCC and EAT-Lancet say

The IPCC's 2019 Special Report on Climate Change and Land concluded that shifting toward plant-based diets is one of the highest-leverage climate actions available. The EAT-Lancet Commission's "planetary health diet" (2019) — designed to feed 10 billion people within planetary boundaries — caps red meat at ~14 g/day and dairy at ~250 g/day, levels far below average Western consumption.

What individual change actually does

• Switching from a high-meat to a vegan diet reduces a person's food-related emissions by about 75%, land use by 75%, and water use by 54% (Scarborough et al., Nature Food 2023, ~55,000-person UK study).
• Even cutting beef alone, while keeping chicken, can cut food emissions by ~35%.
• For most people, dietary change has a larger lifetime carbon impact than switching to an electric car (Wynes & Nicholas, Environmental Research Letters 2017).

What about "regenerative" or grass-fed beef?

Some regenerative grazing genuinely improves local soil and biodiversity. But independent analyses (Garnett et al., FCRN "Grazed and Confused?" 2017) find soil-carbon sequestration offsets at most a small fraction of the methane and land cost of cattle, and the model cannot scale to anything near current beef consumption. Per kilogram, grass-fed beef often has a higher climate footprint than feedlot beef because cattle live longer and belch methane for more years.

You don't have to be perfectly vegan to move the needle. Every meal swapped is a real number. VeggieOS's Impact tab estimates the water, CO₂, land, and animal lives saved by your scans over time.