In the comments thread of another post, Vickie asks:

I have a question for those of you who have already made diet changes to eat locally produced food. I am struggling here. What should a person eat if they live in the north where the growing season is shorter and there is nothing (but meat) produced all winter? Everything seems to be trucked in from somewhere.

That’s a great question! Unfortunately, it’s also enormously difficult to answer. In fact, a pithy article in Newsweek nicely points up the difficulty of this question—and of the more general difficulty with relying on individual awareness to achieve good environmental outcomes. Local food turns out to be a great example:

Although lists of “what you can do to save the planet” include eating locally—buying food that is grown nearby—to reduce your carbon footprint, the calculation is more complicated than counting up your food’s frequent-flier miles. If the local tomato comes from a greenhouse that gobbled up electricity produced from coal and was trucked in via an 8 miles-per-gallon pickup, and a long-distance one was grown in sunny fields and transported by a 400mpg train, you’ll leave a smaller carbon footprint if you opt for the latter.

You can find several more examples like this in a recent New Yorker article.

  • Although I’m a regular at my neighborhood farmer’s market, I’m certainly no food saint. And I ‘m fascinated by how local food calculations reveal just how incredibly difficult it is for consumers to make well-informed decisions, even when they really want to. (Heck, it’s proven mighty difficult even for big grocery corporations to figure out the carbon consequences of their products.) The difficulty is no failing of good intentions: it’s that the global economy is terribly complicated:

    Each calculation depends on the food and where you live, but studies find that dairy products imported by Europe from New Zealand leave half the carbon footprint as local ones, while imported New Zealand lamb (which is pasture-raised) leaves one quarter the carbon footprint as local kinds that rely on energy-intensive feed. While bottled water from the South Pacific is an eco-no-no, “you can’t say that food from thousands of miles away is [worse for the environment],” says Jonathan Harrington, author of the new book “The Climate Diet.” “Transportation is only one piece of it.”

    Okay, okay. I don’t want to make too much out of all this. It’s still true that all else being equal, local food less carbon-intensive than far-away food. And certainly it’s commendable to live (and shop) responsibly — and to think hard about the consequences of our decisions. It’s just that all else usually isn’t equal, and that consequences are often counterintuitive.

    The real lesson here, I think, is that invidual awareness—while laudable—cannot substitute for good policy. To take just one example that I’m obsessed with: a comprehensive global cap on carbon emissions would render largely irrelevant the climate implications of food choices. Of course, there are many other good reasons to choose local food. But some of these too would be better addressed with policy than with consumer choice.