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Cutting Calories to Save the Planet

A new report highlights how relatively small shifts in diet could have substantial impacts on greenhouse gases and land use.

By Nathan Collins


(Photo: Chris Hondros/Getty Images)

Thinking about climate change will likely draw up images of smoke-spewing factories or highways crammed with cars. But food production is also an important piece of the equation, and small changes in diet could go a long way toward cutting greenhouse gases and preserving land that would otherwise be farmed, according to a new report.

“Small, manageable changes,” such as reducing Americans’ enormous—and nutritionally unnecessary—intake of beef and other animal protein could cut greenhouse gas emissions associated with producing food “nearly by half,” says Janet Ranganathan, lead author of the new report and vice president for science and research at the World Resources Institute in Washington, D.C.

“You don’t have to become vegans or vegetarians to have a big impact,” she says.

The report considers a number of different scenarios, with a focus on cutting overall calorie consumption and cutting beef and animal protein consumption in particular. (Raising cattle for beef, it turns out, is a remarkably inefficient, greenhouse-gas intensive way to feed people.) In constructing the scenarios, “we tried to be more realistic,” rather than look at truly extreme shifts, such as moving the entire world to a vegan diet.

“You don’t have to become vegans or vegetarians to have a big impact.”

Then, using consumption data from the United Nations’ Food and Agriculture Organization in combination with a computer model of greenhouse gas emissions, land use, and food production, Ranganathan and her colleagues computed how much impact each scenario could have.

According to the model’s results, even a modest shift from beef to pork and poultry could cut land use and emissions related to food production by 15 percent, Ranganathan says. If the average American were to cut their animal protein consumption by half, greenhouse gas emissions related to food production could drop by 45 percent. Doing so would also preserve an amount of land roughly twice the size of India in the long run.

So what to do? The report offers a number of possible solutions aimed mostly (and somewhat novelly) at private companies, including grocery stores and restaurants. Grocery stores, for example, could put soy milk in the same place as cow milk. Although soy milk doesn’t need to be refrigerated, people would be more likely to buy it if they could see it alongside cow milk, Ranganathan says—and not a few aisles away.

The report, “Shifting Diets for a Sustainable Food Future,” is the eleventh installment in a series of WRI reports on food sustainability and climate, such as the role food waste plays in climate change.