Beef pollutes more than pork, poultry, study says
WASHINGTON — Raising beef for the American dinner table does far more damage to the environment than producing pork, poultry, eggs, or dairy products, a study says.
Compared with other animal proteins, beef produces five times more heat-trapping gases per calorie, puts out six times as much water-polluting nitrogen, takes 11 times more water for irrigation, and uses 28 times the land, says a study published Monday in the journal Proceedings of the National Academy of Sciences.
Cows are not efficient at converting feed to protein for human consumption, said the lead author, Gidon Eshel, an environmental physics professor at Bard College in New York.
Eshel used US government figures to calculate air and water emissions and how much water and land were used to produce the commodities.
While other studies have looked at the issue, this is one of the most comprehensive pieces of research on the environmental costs of meat and other animal protein.
The beef industry called the study ‘‘a gross oversimplification of the complex systems that make up the beef value chain.’’
Kim Stackhouse, sustainability director at the National Cattlemen’s Beef Association, said the industry has improved its environmental sustainability and the United States produces beef with the lowest greenhouse gas emissions of any country.
In the study, pork, poultry, dairy, and eggs all had comparable environmental footprints, so close there were no statistically significant differences among them, Eshel said. But cows were off-the-chart different. The study did not look at plants or fish.
Cows produce considerably more methane — a greenhouse gas that is dozens of times more potent than carbon dioxide — than pigs, chickens, or turkeys do, Eshel said. The manure used to grow feed for cows also releases methane. And because they are bigger, cows eat more food than other animals raised for protein that humans eat. And nitrogen, from fertilizer runoff, can harm rivers, lakes and bays.