Does Local Mean Green?

Locavore (noun) – a person whose diet consists only or principally of locally grown or produced food.

Coined in 2005 at the Bay Area World Environment day, locavore was the Oxford American Dictionary’s word of the year in 2007, and has quickly become common place in both foodie and environmental circles. Among the myriad of reasons to “eat local”, the environment tends to rank high on the list, and the following statistic from a 2001 report is frequently cited.

“Produce arriving by truck traveled an average distance of 1,518 miles to reach Chicago in 1998, a 22 percent increase over the 1,245 miles traveled in 1981.”

A quick glance through my fridge revealed produce from no fewer than 6 countries. That red pepper up there probably traveled the furthest -it’s from Holland. The potatoes, on the other hand, are from right here in Pittsburgh. Although I love a good weekend farmers market as much as the next person, this post is about why I don’t feel an ounce of guilt about eating avocados from Chile and red peppers from Holland.

First, distance traveled is not the only factor that determines greenhouse gas emissions from the transport of our food. In fact the small truck that the local farmer uses to haul a couple crates of strawberries to your farmer’s market is likely to be significantly less efficient than a big rig, a train, or a boat used to ship many tons of strawberries to the supermarket. Even if the food transported on the big rig travels more miles, it’s unclear that it uses more energy. If I’ve learned anything from NPR, it’s that “Trains can move a ton of freight nearly 500 miles on a single gallon of fuel.” Thanks CSX.

Second, transportation accounts for a very small fraction of green house gas emissions. This study , published in April 2012, estimates the potential environmental and nutritional effects of localization in Santa Barbara County (SBC). The study finds, surprisingly, that although SBC is among the top 1% of counties in terms of agricultural production (mostly produce), residents of SBC import approximately 96.7% of their produce. Despite this staggering figure, the authors estimate that 100% localization of produce consumption would decrease greenhouse gas emissions from the “agrifood system” by less than 1%.

Third, small farms aren’t necessarily more environmentally friendly than big farms. Some proponents of the locavore movement point to this study from Sweden comparing 6 small farms to 6 big ones, concluding that small farms are better for the environment than big ones. The study found that the small farms had more than twice as many bird species, butterflies, and herbaceous plant species, and five times more bumblebees. However, this overlooks the fact that since large farms are more efficient, less land needs to be devoted to agricultural production to obtain the same yield. Those small farms may have more species of birds than the large farms, but probably not more than, say, a forest.

Fourth, since the majority of green house gas emissions result from the production of food rather than the transport of food (see point #2), we should also consider ways to reduce the production costs. You can grow tomatoes in Minnesota, peaches in Kansas, rhubarb in California, and apples in Nevada, but you’re probably going to end up using more resources (water, fertilizer, electricity, etc…) than if you grew them in the suitable climate and shipped them to market.

Finally, food from abroad supports foreign economies. There’s a lot of talk about supporting your local economy. Particularly during the slow recovery, we all feel an obligation to get out there and do our part. The reality is that US agriculture robs the developing world of  $31.4 billion annually.

The good news for the locavore movement is that since the food is typically fresher and allowed to ripen longer before being picked, it is indeed quite tasty. The bad news is that eating local isn’t going to save the world, not even close.

Note: After writing this post, I listened to the recent Freakonomics podcast, You Eat What You Are: Part 2, in which Stephen Dubner makes several similar arguments to those above. If you’re interested, you should definitely check it out!