Earth Protect Blog

Vegans produce fewer greenhouse gas emissions, research says Oxford research says vegans produce fewer greenhouse gas emissions

By Cara Buckley

The New York Times

People who follow a plant-based diet account for 75% fewer greenhouse gas emissions than those who eat more than 3.5 ounces of meat a day, and a vegan diet also results in significantly less harm to land, water and biodiversity, according to new research from the University of Oxford.

Although the link between animal agriculture and environmental harm is well-established, earlier studies used scientific modeling to reach those conclusions. By contrast, the Oxford research drew from the actual diets of 55,500 people — vegans, vegetarians, fish eaters and meat eaters — in the United Kingdom and used data from some 38,000 farms in 119 countries.

The peer-reviewed study, led by Peter Scarborough, a professor of population health at Oxford, was published Thursday in the journal Nature Food.

If meat eaters in the United Kingdom who consumed more than 3.5 ounces of a meat a day (slightly less than the size of a quarter-pound burger) cut their intake to less than 1.7 ounces a day (about the amount of a single McDonald’s meat patty) it would be the equivalent of taking 8 millions cars off the road, Scarborough said.

The study found that, compared with meat-heavy diets, vegan diets resulted in 75% less land use, 54% less water use, and 66% less biodiversity loss. A vegan diet avoids all animal products, including meat, eggs and dairy.

In terms of greenhouse gas emissions, people who ate more than 3.5 ounces of meat daily accounted for 22.5 pounds of carbon dioxide emissions a day due to, among other variables, the farming of livestock and land used to grow animal feed. People who ate less than 1.7 ounces of meat accounted for about half that amount, or about 11.8 pounds of carbon dioxide emissions, while fish eaters accounted for 10.4 pounds of carbon dioxide a day, and vegetarian diets produced 9 pounds of carbon dioxide daily. Vegan diets had the lowest totals, accounting for 5.4 pounds of carbon dioxide a day.

There were parallel effects on freshwater pollution and biodiversity loss by diet type. In terms of land and water use and effects on species’ extinction, vegetarians, fish eaters and low-meat diets had similar results.

The study also found that vegans and vegetarians were on average younger than fish and meat eaters.

Scarborough said that although critiques of plant-based diets often highlighted environmental effects of select vegan foods, such as the volume of water required to produce almond milk, the new research showed that plant-based diets had far less of an environmental toll than animal-based ones, regardless of how the food was produced.

In the Oxford study, meat was defined as all land animals. Earlier research has found that organic cow, chicken and pig meat production is just as harmful to the climate as conventional livestock farming.

“What our work says is even in the worst-case scenarios, the environmental footprint of not only vegan diets but low-meat diets are much, much better than high-meat-consuming diets,” Scarborough said.

“This reinforces the message that the amount of meat we consume is strongly related with our environmental footprint,” Scarborough said. “Small changes from being a high meat eater to a low meat eater can make a huge difference in environmental impact.”

Globally, the food system is responsible for about one-third of planet-heating emissions, 70% of freshwater use and 78% of freshwater pollution. To slow the worst climate effects, the United Nations has called for a drastic reduction in meat consumption.

The Oxford study was funded by the Wellcome Trust, an independent global charity based in London focused on health research.