Meat, dairy and the planet

Going vegan cuts a diet’s climate cost sharply: a 2023 Oxford study of 55,504 people in the UK found vegan diets produced about a quarter of the emissions of diets with 100g or more of meat a day.

Grass-fed and regenerative beef is not carbon-negative at scale: an Oxford-led review (2017) found better grazing could offset at most 20 to 60% of grazing livestock’s emissions, and only for a few decades.

Cow methane is a serious climate problem: a tonne traps 27 times as much heat as CO2 over a century (IPCC, 2021). The figure overstates a steady herd’s warming and understates a growing one’s, and cuts pay off fast.

What we eat matters for the climate alongside fossil fuels: the IPCC (2022) put food systems at 31% of global greenhouse gas emissions in 2018, and Clark et al. (2020) found food on current trends would breach 1.5°C.

Cow methane is recycled carbon, but that only slightly lowers its warming: the IPCC (2021) rates a tonne at 27 times CO2 over a century, and fossil methane at about 30. A steady herd keeps up the warming it has caused.

Soy farming does clear forest, but cattle clear far more: Singh and Persson (2026) linked 42% of deforestation from 2001 to 2022 to pasture and 16% to all oil crops, soy included. Most soy feeds livestock.

A mainly plant-based diet could feed the world: Berners-Lee and colleagues (2018) found today’s crops could feed 9.7 billion people in 2050 if most meat and dairy gave way to plants and food reached far more people.

Farming can work without animals: manure only returns nutrients from feed, and animal products use 83% of farmland for 18% of calories (Poore and Nemecek, 2018). Stockfree soils need legumes to hold their organic matter.

Palm oil is vegan and has cleared real forest, but cattle pasture has cleared far more: the World Resources Institute (2021) found pasture replaced 45.1 million hectares of tree cover from 2001 to 2015, oil palm 10.5 million.

Animal farming is one of the biggest drivers of biodiversity loss: changing how land and sea are used is the top cause (IPBES, 2019), and meat, dairy, eggs and farmed fish take up 83% of farmland (Poore and Nemecek, 2018).

If everyone went vegan, the world would need about three-quarters less farmland: Poore and Nemecek (2018) found food’s land use would fall by 3.1 billion hectares, mostly pasture that could return to natural vegetation.

Animal farming uses a lot of water even with rain left out: in a 2023 Oxford study of 55,504 UK adults, vegans’ diets used 46% of the water of high meat-eaters’. Nuts and rice are thirsty too, and modelled diets vary.

Seafood is often unsustainable: the FAO found 37.6% of assessed marine fish stocks overfished in 2023. Most landed fish came from stocks it rated sustainable, a test that ignores harm to seabirds, turtles and the seabed.

It depends how you count: per litre, almond milk draws less fresh water than cow’s milk in Poore and Nemecek’s 2018 data, 371 litres to 628, but more per gram of protein or weighted for scarcity (2023 review).

Ocean dead zones are a meat problem as well as a fertiliser one: a 2023 Oxford study found UK vegans’ diets caused 27% of the nutrient pollution of diets with 100g or more of meat a day.

Per kilogram, avocados and quinoa emit far less than meat: estimates put them at 0.6 to 2.5kg of CO2-equivalent, against a mean of 9.9kg for poultry in Poore and Nemecek’s 2018 data. Avocado farming has real local water costs.

Eating local does little for your food’s carbon footprint: in Poore and Nemecek’s 2018 data, transport is about 6% of food’s emissions and 0.5% of beef’s, so what you eat matters far more than where it came from.

Factory farming helps new diseases emerge, says a 2020 UN report, and the 2009 flu pandemic, from pigs in Mexico, killed 151,700 to 575,400 people in its first year (US CDC, 2012). Wildlife is still the commonest source.

Slaughterhouse jobs are a weak case for meat: US meat and poultry workers are seriously injured at twice the average rate (Labor Department, 2024). Eating more plants would cut those jobs and create others, a 2026 review found.