Eating less meat could help slow global warming by reducing the number of livestock and thereby decreasing the amount of methane flatulence from the animals, scientists said on Thursday.
In a special energy and health series of the medical journal The Lancet, experts said people should eat fewer steaks and hamburgers. Reducing global red meat consumption by 10 percent, they said, would cut the gases emitted by cows, sheep and goats that contribute to global warming.
"We are at a significant tipping point," said Geri Brewster, a nutritionist at Northern Westchester Hospital in New York, who was not connected to the study.
"If people knew that they were threatening the environment by eating more meat, they might think twice before ordering a burger," Brewster said.
Other ways of reducing greenhouse gases from farming practices, like feeding animals higher-quality grains, would only have a limited impact on cutting emissions. Gases from animals destined for dinner plates account for nearly a quarter of all emissions worldwide.
"That leaves reducing demand for meat as the only real option," said Dr. John Powles, a public health expert at Cambridge University, one of the study's authors.
The amount of meat eaten varies considerably worldwide. In developed countries, people typically eat about 224 grams per day. But in Africa, most people only get about 31 grams a day.
With demand for meat increasing worldwide, experts worry that this increased livestock production will mean more gases like methane and nitrous oxide heating up the atmosphere. In China, for instance, people are eating double the amount of meat they used to a decade ago.
Powles said that if the global average were 90 grams per day, that would prevent the levels of gases from speeding up climate change.
Eating less red meat would also improve health in general. Powles and his co-authors estimate that reducing meat consumption would reduce the numbers of people with heart disease and cancer. One study has estimated that the risk of colorectal cancer drops by about a third for every 100 grams of red meat that is cut out of your diet.
"As a society, we are overconsuming protein," Brewster said. "If we ate less red meat, it would also help stop the obesity epidemic."
Experts said that it would probably take decades to wane the public off of its meat-eating tendency. "We need to better understand the implications of our diet," said Dr. Maria Neira, director of director of the World Health Organization's department of public health and the environment.
"It is an interesting theory that needs to be further examined," she said. "But eating less meat could definitely be one way to reduce gas emissions and climate change."