The Carbon Cost: Farm to Fork

It's the golden rule of the local-food movement: the fewer miles that food travels, the better for the environment. The only problem is, it may not be true. "Very few studies support the idea that local-food systems are greener," says Rich Pirog of Iowa State University's Leopold Center for Sustainable Agriculture. When it comes to calculating the carbon cost of a certain dish, the method of transport matters as much as the distance from farm to fork. Sea-freight emissions are less than half of those associated with airplanes, trains are cleaner than trucks and a tractor-trailer can be a green machine compared with an old pickup. If you live east of Columbus, Ohio, it's actually greener to drink French Bordeaux than wine from California, which is trucked over the Rockies, according to one study. How food is grown and harvested is also key, says Gail Feenstra, a food-systems analyst at the University of California, Davis. New York state apples, for instance, can be less ecofriendly than those imported from New Zealand, where, among other things, growing conditions produce greater yields with less energy. We need a complete picture of carbon emissions, Feenstra says—not just a mile marker.