Berry hopes it will serve as a foundation for future research that will help us fight climate change.

“We’re beginning to see a number of papers looking at different ways consumers can make more environmentally friendly decisions across contexts,” he said. “This area is just beginning to take off — and, I hope, gaining traction in our field.”

Adding CO2e labels to menus works, research shows

To determine how consumers respond to receiving information about their food’s carbon footprint, Berry and his coauthors conducted two studies using three types of menu labels.

The first menu label simply presents the numeric information about each menu item’s carbon footprint. The second flags items that are below a specific emission threshold, such as the “Cool Foods Meals” menu program developed by the World Resources Institute and recently implemented by Panera Bread. The third option uses stop signs on the menu to indicate which foods have high emissions.

“The numeric information works in the appropriate directions, so that’s good,” Berry said. The potential unintended consequence arises with the “Cool Foods Meals” option, which the researchers found could lead consumers to incorrect conclusions.

“If you have an item that’s just above the threshold and then an item that’s just under the threshold, then what a number of consumers are doing is they’re choosing the item that’s just under the threshold — so, the one with the ‘Cool Foods’ menu icon,” Berry said.

If two menu items are very similar in their environmental impact, but one is eligible for the icon and the other isn’t, the icon could be driving perceptions in an unhelpful direction. While consumers should be focused on the value of ordering a salad instead of a hamburger, for example, they might be stuck debating various types of salads.

Ultimately, all three types of labels were found to have potential benefits to consumers when compared with control groups that had no information, but adding numeric information about a meal’s CO2e emissions to a restaurant’s menu may be the most objective and least likely to mislead consumers, the studies show.

The research also found that the presence of menu labels could lead consumers to view the restaurant more positively.

“Even in the presence of that stop sign warning, they’re actually perceiving the restaurant to be more concerned about the environment,” Berry said.

Building on decades of nutrition labeling research

Berry has spent much of his career examining consumers’ responses to food labeling and nutrition disclosures, from calorie labeling on menus to health warnings in advertisements for tobacco products.

“I’m applying my expertise on disclosures and health communications to an environmental sustainability context, which, personally, I feel is extremely important as we combat climate change,” Berry said.

Although CO2e emissions labeling can in some ways be compared to familiar practices such as adding calorie counts to menus, there’s one crucial difference: Calorie labeling became mandatory for many restaurants in 2018, but CO2 emissions labeling is unregulated and completely voluntary.

“There’s no mandate — there’s not even self-regulation around this yet — which provides the opportunity to look at potential avenues for disclosure,” Berry said.

Finding ways to encourage consumers to make climate-conscious food decisions is just one way that we can combat climate change, he said. Consumers should be more aware of how the decisions they make every day could affect the environment, from selecting what to have for lunch to choosing how to commute to work.

“In my opinion, this is just one piece of the puzzle — an important piece, but one piece of the puzzle in fighting climate change,” Berry said. “I hope that this motivates additional research thinking about CO2e communications and disclosures in other contexts as well.”