Philosopher Peter Singer has just published a new book, The Way We Eat: Why Our Food Choices Matter (Is it just me, or does there seem to be a lot of talk about food lately? Crunchy Cons, The Omnivore’s Dilemma, an entire issue of Sojourners dedicated to the topic; people seem to have food on the brain. Is food the new sex?).

Anyway, in this interview at Salon, he points out that “buying local,” as we’re often urged to do, may not be the best thing to do, all things considered:

In your book you say that socially responsible folks in San Francisco would do better to buy their rice from Bangladesh than from local growers in California. Could you explain?

This is in reference to the local food movement, and the idea that you can save fossil fuels by not transporting food long distances. This is a widespread belief, and of course it has some basis. Other things being equal, if your food is grown locally, you will save on fossil fuels. But other things are often not equal. California rice is produced using artificial irrigation and fertilizer that involves energy use. Bangladeshi rice takes advantage of the natural flooding of the rivers and doesn’t require artificial irrigation. It also doesn’t involve as much synthetic fertilizer because the rivers wash down nutrients, so it’s significantly less energy intensive to produce. Now, it’s then shipped across the world, but shipping is an extremely fuel-efficient form of transport. You can ship something 10,000 miles for the same amount of fuel necessary to truck it 1,000 miles. So if you’re getting your rice shipped to San Francisco from Bangladesh, fewer fossil fuels were used to get it there than if you bought it in California.

In the same vein, you argue that in the interests of alleviating world poverty, it’s better to buy food from Kenya than to buy locally, even if the Kenyan farmer only gets 2 cents on the dollar.

My argument is that we should not necessarily buy locally, because if we do, we cut out the opportunity for the poorest countries to trade with us, and agriculture is one of the things they can do, and which can help them develop. The objection to this, which I quote from Brian Halweil, one of the leading advocates of the local movement, is that very little of the money actually gets back to the Kenyan farmer. But my calculations show that even if as little as 2 cents on the dollar gets back to the Kenyan farmer, that could make a bigger difference to the Kenyan grower than an entire dollar would to a local grower. It’s the law of diminishing marginal utility. If you are only earning $300, 2 cents can make a bigger difference to you than a dollar can make to the person earning $30,000.