Change your diet, help the planet

If your household is anything like the American average, your diet generates lots of greenhouse gas emissions: roughly the same amount in a single week, a new study finds, as a drive from Washington, D.C. to Trenton.

Food requires huge amounts of energy to grow. It must be transported from farms in rail cars or semi trucks. Then it is processed, packaged, stored, shelved, cooked and delivered — a complex industrial supply chain that generates an estimated 16 percent of U.S. greenhouse gas emissions, according to a study in the journal Food Policy.

Consumers can make changes to bring that number down, said Rebecca Boehm, a postdoctoral fellow at the Rudd Center for Food Policy and Obesity at the University of Connecticut and lead author of the study.

“If people reduced their spending on protein foods by 18 percent, they’d see almost a tenfold reduction in household greenhouse gas emissions,” Boehm said.

Here are Boehm’s other evidence-based tips for shrinking your diet’s carbon footprint.

Eat less red meat and dairy

Studies consistently show that animal agriculture is the most carbon-intensive type of farming, in part because livestock such as cows and sheep produce methane as part of their digestive processes. To further compound the issue, Americans eat lots of red meat: 54 pounds per person last year, according to the Department of Agriculture.

Some researchers have urged people to go vegan, citing the climate gains. But Boehm says smaller changes, like the 18-percent reduction, could also go a pretty long way. That’s particularly true if people make up the difference with less-intensive proteins, such as seafood, poultry and beans.

Research suggests that trading beef for something like chicken cuts emissions more than switching between different types of beef.

“It’s more impactful,” Boehm said, “to switch to plants or seafood or poultry.”

Buy local vegetables and melons

Compared to red meat, produce doesn’t have much of an on-farm carbon footprint. But that changes once the fruits and veggies leave the farm. Boehm’s study shows that vegetables and melons generate particularly high emissions during transport — probably because they travel long distances on refrigerated trucks to restaurants and stores.

Consumers may want to buy vegetables and melons locally, Boehm said. For many consumers, this rule limits when they can eat certain foods: no more asparagus or watermelon in the offseason.

Should concerned eaters start buying everything local? That would cut emissions from transportation. But Boehm said that, for most foods, there’s no point worrying about it.

“For certain industries, like vegetables and melons, the postproduction emissions are a large share of total emissions,” she said.

Shop at stores and restaurants that watch their emissions

Discussions about food and greenhouse gas emissions tend to focus on farms. But emissions are also a major problem at grocery stores and restaurants.

“It’s not just about the food you eat — it’s about all the other things that are required to bring the food to you,” she said.

Boehm admits that it’s difficult for consumers to prompt change at the industry level — but they can support businesses that are documenting and reducing their carbon emissions. One restaurant group in Portland, Ore., has published dish-by-dish emission data online. The Zero Foodprint project helps restaurants calculate and offset their carbon footprints. Major grocery chains, including Walmart and Meijer, have also tweaked their supply chains to reduce emissions.