How bad is beef for Earth? Scientists have number

A new Israeli-American study tells Americans exactly how guilty to feel about the animal-based products they eat – finding that beef is 10 times worse for the environment than other meats or dairy.

Dairy, the research also shows, is just as destructive as popular meats other than beef. Score one for vegans.

Published last week in the journal Proceedings of the National Academy of Sciences, the study makes use of American food production data to calculate the respective tolls that beef, poultry, pork, dairy, and eggs take on the planet. The findings could help inform personal dietary choices and government policies.

“What we found is that there is a very large difference between beef and all the other items when it comes to the environmental burden of production, said Prof. Ron Milo, a biological physicist at the Weizmann Institute’s plant sciences department and one of the leaders of the study. “Also, perhaps surprisingly, dairy was no better than chicken or pork for the environment.”

There is quite a bit of science on the environmental damage caused by food production, but the Israel-American study is the most up to date and comprehensive research yet on animal-derived foods.

Using information from the U.S. Department of Agriculture and other sources, the researchers developed equations to estimate the environmental costs per calorie and per unit of protein for each type of food. The costs they looked at included use of land, water, and nitrogen fertilizer and greenhouse gas emissions. Because they had access to high-quality data, the researchers were able to include factors like transportation distances and livestock feed type in the costs.

The biggest challenge, Milo says, was determining a single number for each cost based on a variety of farming techniques. For example, raising cattle in arid parts of the western United States uses enormous amounts of land but relatively little irrigation water. Cattle in feedlots, on the other hand, eat mostly corn, which requires less land but much more irrigation and fertilizer.

The researchers also had to take complex environmental systems into account. For example, land use not only ties up valuable real estate, it is also the main cause of biodiversity loss, and nitrogen fertilizer pollutes natural waters.

Running the numbers revealed that beef is the least eco-friendly source of protein. While this is not news, the size of the environmental cost gap between producing beef and other animal based foods is a surprise.

Taking all the costs into account, producing beef is on average 10 times worse for the environment than producing poultry, pork, dairy, or eggs, the study finds. Cattle, it says, require an average of 28 times more land and 11 times more irrigation water, release five times more greenhouse gases and consume six times more nitrogen than do eggs or poultry.

Poultry, pork, dairy, and egg production all do about the same environmental damage as each other, according to the study. This finding was also surprising, because dairy production is often thought to be relatively “green.” The price of irrigating and fertilizing the crops to feed dairy cows, which convert calories less efficiently than other livestock, boosted dairy’s costs in the study.

In addition to helping people make better-informed choices about their diets, the study could guide official agricultural and marketing decisions, the researchers say. Models based on the research could help governments around the world better ensure food security through sustainable practices.

“As a scientist, I just provide the information,” said Milo. “It’s up to policymakers to use it.”

As a bonus, the researchers also analyzed three staple plants: wheat, rice, and potatoes. In line with previous research, they found that the environmental costs of these staples were much lower than those of meat and dairy – 10 to 100 times lower than beef and two to six times lower than the other foods, taken together on average.

Follow-up studies are underway to expand the approach used in the study to additional types of food, like fruits and vegetables, the researchers say.

Only then would you know exactly what to order at a vegan cafe.