Subscribe now

Earth

Going vegetarian halves CO2 emissions from your food

By Michael Slezak

26 June 2014

New Scientist Default Image

One of these is better for the environment

(Image: Vasko Miokovic Photography/Getty Images)

If you stop eating meat, your food-related carbon footprint could plummet to less than half of what it was. That is a much bigger drop than many previous estimates, and it comes from a study of people’s real diets.

As much as a quarter of our greenhouse gas emissions come from food production. But it’s not clear how much would really be saved if people swapped their beef steaks for tofu burgers. On some estimates, going vegetarian could cut out 25 per cent of your diet-related emissions. But it all depends on what you eat instead of the meat. With some substitutions, emissions could even rise.

So Peter Scarborough and his colleagues at the University of Oxford took data on the real diets of more than 50,000 people in the UK, and calculated their diet-related carbon footprints.

“This is the first paper to confirm and quantify the difference,” says Scarborough.

Stop those emissions

They found that the benefits could be huge. If those eating more than 100 grams of meat a day – a fairly small rump steak – went vegan, their food-related carbon footprint would shrink by 60 per cent, saving the equivalent of 1.5 tonnes of carbon dioxide a year.

Perhaps more realistically, if someone eating more than 100 grams of meat a day simply cut down to less than 50 grams a day, their food-related emissions would fall by a third. That would save almost a tonne of CO2 each year, about as much as an economy return flight between London and New York.

Pescatarians, who eat fish but not other meat, are almost as carbon-friendly as vegetarians, creating only about 2.5 per cent more food-related emissions. But vegans can feel the most superior, pumping out 25 per cent less emissions than vegetarians, who still eat eggs and dairy.

“In general there is a clear and strong trend with reduced greenhouse gas emissions in diets that contain less meat,” says Scarborough.

Where to cut?

There are other ways of reducing emissions, such as driving and flying less, but changing food habits will be easier for many, says Scarborough. “I think it is easier to change your diet than to change your travel behaviour, but others may not agree.”

“This research presents a strong case for the greenhouse gas benefits of a low-meat diet,” says Christopher Jones of the University of California, Berkeley.

In 2011, Jones compared all the ways US households can cut their emissions. Although food was not the biggest source of emissions, it was where people could make the biggest and most cost-effective savings, by wasting less food and eating less meat. Jones calculated that saving each tonne of CO2 emissions would also save the household $600 to $700 (Environmental Science & Technology, DOI: 10.1021/es102221h).

“Americans waste about a third of the food they buy, and eat about 30 per cent more calories than recommended, on average,” says Jones. “Reducing food purchases and physical consumption would have even greater greenhouse gas benefits than reducing meat consumption in the American case.”

Journal reference: Climatic Change, DOI: 10.1007/s10584-014-1169-1

Topics:

Sign up to our weekly newsletter

Receive a weekly dose of discovery in your inbox! We'll also keep you up to date with New Scientist events and special offers.

Sign up