Estimating Carbon Impacts

Efforts to curb climate change are hampered by consumers’ lack of knowledge about what causes harm.

“BEEF IS THE SUV of food,” says Rick Larrick, a professor of management and organizations at Duke University’s Fuqua School of Business in Durham, North Carolina. He was one of four researchers who studied how efforts to curb climate change can be hampered by consumers’ lack of knowledge. The study was led by Adrian Camilleri, a senior lecturer in consumer psychology at the University of Technology Sydney’s Business School in Australia; he was joined by Larrick, Shajuti Hossain of Duke’s Law School, and Dalia Patino-Echeverri of Duke’s Nicholas School of the Environment.

The food system uses large amounts of energy and generates about the same proportion of global greenhouse gas emissions as transportation. But the researchers found that people don’t give the same thought to food’s environmental impact. They asked more than 1,000 participants to rate the energy used—and the greenhouse gas emitted—by the production of one serving of 19 different kinds of food, and by using one of 18 different appliances for one hour.

Participants underestimated the environmental impacts of both appliance use and food production, but they underestimated the impacts of food significantly more. They equated the impact of one serving of beef with using a 25-watt CFL bulb for an hour, when it creates as much greenhouse gas as running a microwave for two hours. They also underestimated the environmental impact of beef compared to other kinds of food.

“To produce and distribute a serving of beef releases about 50 times more greenhouse gas than putting corn on your table,” says Camilleri, who started the research as a postdoctoral researcher at Duke. “People think beef production emits only twice as much as the corn.”

Customers might make different choices if they understood the carbon footprints of their food options. Researchers showed 120 participants images of six different cans of soup—three beef, three vegetable—and asked participants to buy three cans using money they received for taking part in the research. Those who had been given information about the carbon footprint of each soup chose to buy, on average, one can of beef soup, compared to 1.5 cans for those who had not.

“We need creative ways to get people this information. In the absence of information, people just aren’t aware of the impact of their choice,” says Larrick.

“Consumers underestimate the emissions associated with food but are aided by labels” appeared online December 17, 2018, in Nature Climate Change. View a video of Larrick discussing the research.