It may seem counterintuitive that buying something grown halfway around the world can be more eco-friendly than buying something grown just a county or two away. Strange, but true. Someone should tell the “locavores,” who encourage people to buy food from the closest sources possible — like farmers markets and community supported agriculture (CSA) programs — in order to reduce the “food miles” of what’s on our plates. It sounds nice, but as New York Times contributor Stephen Budiansky wrote recently, some of the hip and popular locavore terms don’t mean much when actual facts are introduced:

Studies have shown that whether it’s grown in California or Maine, or whether it’s organic or conventional, about 5,000 calories of energy go into one pound of lettuce. Given how efficient trains and tractor-trailers are, shipping a head of lettuce across the country actually adds next to nothing to the total energy bill. …

A single 10-mile round trip by car to the grocery store or the farmers’ market will easily eat up about 14,000 calories of fossil fuel energy. Just running your refrigerator for a week consumes 9,000 calories of energy. That assumes it’s one of the latest high-efficiency models; otherwise, you can double that figure. …

[H]ouseholds make up for 22 percent of all the energy expenditures in the United States. Agriculture, on the other hand, accounts for just 2 percent of our nation’s energy usage; that energy is mainly devoted to running farm machinery and manufacturing fertilizer.

As usual, reality is beholden to a more complicated circumstance than the sound bite. Researchers at New Zealand’s Lincoln University compared the emissions and energy performance of their domestic agriculture industry and found that shipping lamb to England was two to four times less emissions-intensive than serving the Brits lamb produced in their own country. That may not seem very sensible until you consider the economies of scale. (Similarly, fresh flowers grown in Kenya and shipped to Europe have a smaller environmental impact than flora grown more locally in Holland and sold in neighboring countries.)

There are certainly some good reasons to buy local, like supporting farmers near where you live, but it isn’t the environmental panacea that its proponents wish it to be.