THE term "food miles" - how far food has traveled before you buy it - has entered the enlightened lexicon. Environmental groups, especially in Europe, are pushing for labels that show how far food has traveled to get to the market, and books like Barbara Kingsolver's "Animal, Vegetable, Miracle: A Year of Food Life" contemplate the damage wrought by trucking, shipping and flying food from distant parts of the globe.
There are many good reasons for eating local - freshness, purity, taste, community cohesion and preserving open space - but none of these benefits compares to the much-touted claim that eating local reduces fossil fuel consumption. In this respect eating local joins recycling, biking to work and driving a hybrid as a realistic way that we can, as individuals, shrink our carbon footprint and be good stewards of the environment.
On its face, the connection between lowering food miles and decreasing greenhouse gas emissions is a no-brainer. In Iowa, the typical carrot has traveled 1,600 miles from California, a potato 1,200 miles from Idaho and a chuck roast 600 miles from Colorado. Seventy-five percent of the apples sold in New York City come from the West Coast or overseas, the writer Bill McKibben says, even though the state produces far more apples than city residents consume. These examples just scratch the surface of the problem. In light of this market redundancy, the only reasonable reaction, it seems, is to count food miles the way a dieter counts calories.
But is reducing food miles necessarily good for the environment? Researchers at Lincoln University in New Zealand, no doubt responding to Europe's push for "food miles labeling," recently published a study challenging the premise that more food miles automatically mean greater fossil fuel consumption. Other scientific studies have undertaken similar investigations. According to this peer-reviewed research, compelling evidence suggests that there is more - or less - to food miles than meets the eye.
It all depends on how you wield the carbon calculator. Instead of measuring a product's carbon footprint through food miles alone, the Lincoln University scientists expanded their equations to include other energy-consuming aspects of production - what economists call "factor inputs and externalities" - like water use, harvesting techniques, fertilizer outlays, renewable energy applications, means of transportation (and the kind of fuel used), the amount of carbon dioxide absorbed during photosynthesis, disposal of packaging, storage procedures and dozens of other cultivation inputs.