The limits of "food miles"

Yesterday, Will Wilkinson spoke on NPR's Marketplace about the locavore movement. He pointed out that despite a 25% increase in the distance that the average American's dinner traveled over the past ten years, carbon emissions have only increased by 5%. This fact is the result of efficient forms of transportation (like large tankers), and it highlights the limitations of "food miles". Wilkinson notes:

"A tomato raised in a heated greenhouse next door can be more carbon-intensive than one shipped halfway across the globe. And cows spew a lot more greenhouse gas than hens, or kumquats, so eating just a bit less beef can do more carbon-wise than going completely local. It's complicated."

If you're already a vegetarian, your diet already has low carbon-intensity (except for the cheese). However, depending on where you live and what can be grown efficiently, going local is not always the most environmentally friendly option.

However, the locavore movement is as much political as it is environmental. As one of the comments on NPR's website indicates, supporting family farms and supporting the local economy are considered equally prominent goals:

"Eating locally and seasonally keeps more of the food dollar in the local economy. In western Minnesota where I'm from that is very important. Local foods will keep more people on small farms and help decrease our national dependence on petroleum. Modern corn and soybean production puts money in Monsanto, Archer Daniel Midland, and the other conglomerates pockets at the expense of local economies. Local food puts the food dollar into local farmer's and grocer's bank accounts."

This is an example of what Frederic Bastiat called the "broken windows fallcy". This concept comes from Bastiat's fable about a glazier whose son breaks a window, requiring his services to fix it. On-lookers conclude that since the son's action has created work for the man, breaking windows must be an effective way to stimulate the economy. However, while this is good for the glazier, it lowers everyone else's standard of living, leaving them with less money to spend on other goods and services, both from within and outside the local economy.

How does this relate to the local foods movement? Paying more for locally-grown food keeps local farmers in business, but it comes at a cost to everyone else in the community. This is akin to a voluntary tax on local residents, used to fund local farmers.

Additionally, local farmers would be much better served if the government eliminated the billions of dollars in farm subsidies that it hands out every year. Though these subsidies are often sold as "support for local farmers" they mostly go to large agribusiness companies. Removing the subsidies would improve the relative competitiveness of small farmers without increasing the burden on local consumers.

The local foods movement has been successful at helping people understand the environmental impact of their diets. Even the normally libertarian economist Tyler Cowen recently acknowledged, "we do have duties to behave more responsibly at the dinner table". But while "food miles" has been a useful concept, we need to get much more sophisticated if we want to make real environmental, as well as economic, progress.