If you’re trying to reduce your carbon footprint, you may want to think twice next time you reach for a burger. According to a new study, people with a high-meat diet contribute more than twice the diet-related greenhouse gas emissions to the atmosphere as a vegan, and a little less than twice the emissions of a vegetarian.
The study, published in the journal Climatic Change, looked at the diets of 55,504 people in the U.K., who took a survey asking them how many times per year they ate 130 different foods. The researchers then placed the people into groups of high, medium, and low meat-eaters, along with fish-eaters, vegetarians and vegans, based on their responses to the survey. They found that, on average, meat-eaters contributed 46 to 51 percent more food-related greenhouse gas emissions than fish eaters, 50 to 54 percent more than vegetarians and 99 to 102 percent more than vegans. The difference between high meat-eaters and vegetarians and vegans was even more distinct — high meat-eaters contributed an average 7.19 kg of CO2 equivalent each day, while vegetarians contributed 3.81 kgCO2e and vegans contributed 2.89 kgCO2e.
The study also noted that health benefits often came with choosing to eat less meat — the researchers noted “significant trends” toward higher intake of fiber and fruits and vegetables and lower intake of saturated fat as animal-based foods decreased in diets. The study, the researchers write, illustrates that eating less meat, even on the individual level, can help reduce carbon emissions.
“This work demonstrates that reducing the intake of meat and other animal based products can make a valuable contribution to climate change mitigation,” the researchers write. “Other work has demonstrated other environmental and health benefits of a reduced meat diet. National governments that are considering an update of dietary recommendations in order to define a ‘healthy, sustainable diet’ must incorporate the recommendation to lower the consumption of animal-based products.”
The study is the first, according to the researchers, to quantify the differences in self-reported diets among meat-eaters, fish-eaters, vegetarians, and vegans. But it’s not the first to demonstrate the high-carbon intensity of meat, eggs and dairy products. According to the U.N. Food and Agriculture Organization, livestock is responsible for 14.5 percent of the world’s emissions, with the majority — 45 percent — coming from the process of growing and shipping the corn and soy used to feed most cattle, pigs, and poultry. Cow’s digestive processes — namely, their burps and farts — make up the next 39 percent of livestock’s contribution to climate change, according to the FAO, and manure decomposition makes up 10 percent.
And the idea that, because meat’s contribution to climate change is significant, eating less of it can help combat climate change has been around for a while. In 2007, Gidon Eshel, a Bard Center fellow at New York’s Bard College, said according to his studies, the diet of an average American requires the production of an extra ton and a half of CO2 equivalent compared to a vegetarian diet.
“If you simply cut down from two burgers a week to one, you’ve already made a substantial difference,” Eshel told the New York Times.
But as developing countries become wealthier, demand for meat around in some parts of the world is rising. In China, pork consumption has skyrocketed since the mid-1970s, due to higher income and standards among the country’s citizens. That’s why scientists from the U.N. have urged people in rich countries to cut back on their meat consumption, in hopes of softening the blow this rise in meat consumption in developing countries will have.
“Eat meat, but less often — make it special,” Mark Sutton, lead author of a U.N. Environment Programme 2013 study on meat consumption, said. “Portion size is key. Many portions are too big, more than you want to eat. Think about a change of culture that says, ‘I like the taste, but I don’t need so much of it.'”
Scientists are also looking into other ways to reduce the carbon footprint of agriculture, including better soil management and more easily-digestible feeds. But in a time when drought is driving up cattle prices (and rising temperatures threaten the global poultry supply), eating less meat as a way of helping the climate makes sense from a personal cost standpoint. A study in 2011 that compared opportunities for carbon reduction in U.S. households found changes in food habits — eating less meat and wasting less food — helped households achieve some of the largest savings in money and carbon emissions.