Transportation makes up a fifth of all food system carbon emissions

We depend on our grocery stores to provide access to produce and food products from all around the world, any time of the year. And while we’ve come to expect avocados on the East Coast in the middle of winter, these culinary delights come with a price for the planet. 

New research out yesterday in Nature Food shows that food miles, or the distance between the place where food is grown to your plate, has a much higher carbon footprint than previously estimated. The carbon cost is actually around 19 percent of all food-related transportation emissions. 

Taking the entirety of the food supply chain into account, global food miles add up to around 3 gigatons of carbon dioxide equivalent emissions, which stands around 3.5 to 7.5 times higher than previous estimates. All of that amounts to about half of direct emissions from road vehicles, the study authors write. This is a significant deviation from previous estimates that put food transportation at under 5 percent of emissions of the global food system.

Unsurprisingly, these results are especially relevant for wealthy countries with especially well-stocked grocery stores. The authors looked at food miles in 74 different countries, incorporating 37 economic sectors like livestock or vegetables, transport distances, and the weight of the commodities. While the largest countries in the world, China, India, and the US, make up most of these food emissions, smaller wealthy nations tend to have a bigger impact per person. For example, combine the US, France, Germany, and Japan, and the numbers crunch to around 12 percent of the world’s population, but nearly half of the emissions associated with food transport. 

“Prior to our study, most of the attention in sustainable food research has been on the high emissions associated with animal-derived foods, compared with plants,” David Raubenheimer, coauthor and nutritional ecologist at the University of Sydney said in a release.  It’s true that meat and animal products do rack up a considerable carbon footprint: Research from 2018 shows how 20 percent of Americans are responsible for half of the country’s food emissions. Other studies suggest that most of us are eating too much protein in our diets—the overconsumption also likely contributing to emissions. However, this new study actually shows that eating fruits and vegetables is a noteworthy dilemma. Fresh produce Is especially a major player when it’s out of season and shipped from far away. 

Transportation associated with fruits and vegetables added up to around 36 percent of the total food-miles emissions (or over 1 billion tons of carbon dioxide equivalent), nearly doubling the amount of greenhouse gas emissions from their production. Meat production, on the other hand, emits around 3 billion tons of carbon dioxide equivalent, but transportation costs a little over 100 million tons. The higher emissions for fruits and vegetables is largely due to carbon-intensive refrigeration to keep produce looking as ripe and plump as possible. 

[Related: Here’s the actual impact of cutting down on red meat]

On top of the surprisingly high environmental cost of fruits and vegetables in general, over half of the emissions came from moving food around inside of countries, with less contributed from international transport. Essentially, your indulgent French cookies or Korean ramen shipped to your neighborhood store aren’t just what’s driving up emissions—even getting a “US grown” banana could rack up some serious environmental mileage.

The answer to this problem, however, is quite simple—learn about and purchase foods in season where you live.

“One example is the habit of consumers in affluent countries demanding unseasonal foods year-round, which need to be transported from elsewhere,” Manfred Lanzen, another author and professor of sustainability research at the University of Sydney, said in the release. “Eating local seasonal alternatives, as we have throughout most of the history of our species, will help provide a healthy planet for future generations.”

This may initially seem like a nuisance when you’ve got a hankering for mango or pineapple while living in a cold region, but there are lots of tools out there that can help you determine when your favorites are in season and where they are coming from. For example, the nonprofit Grace Communications Foundation shows that in Georgia, now is the time to dive into cantaloupe, peaches, and zucchini; on the other side of the country in Oregon it’s time for rhubarb, endives, and apples.

If the whole population of the planet ate locally, emissions would drop by around a third of a gigatonne. For foods that must be transported, shifting to cleaner vehicles and natural refrigerants could help lessen the blow.