(Editors note: I he local-food movement has been gaining momentum in developed countries, and in many developing countries as well in recent years; in the United States alone, sales of locally grown foods, worth about $4 billion in 2002, could reach as much as $7 billion by 2011. Local food's claimed benefits are driving health- and environment-conscious consumers to seek alternatives to the industrial agriculture system whose products dominate grocery-store shelves. It is also linked to the localization efforts of people who believe that rising transport costs and reaction to globalization will trigger a shortening of economic links and greater reliance on local and regional economies. This two-part series examines the potential impacts of greater localization of food, beginning with the environmental effects and then, in our July/August issue, the economic implications.)
In 1993, a Swedish researcher calculated that the ingredients of a typical Swedish breakfast--apple, bread, butter, cheese, cot-fee, cream, orange juice, sugar--traveled a distance equal to the circumference of the Earth before reaching the Scandinavian table. In 2005, a researcher in Iowa found that the milk, sugar, and strawberries that go into a carton of strawberry yogurt collectively journeyed 2,211 miles (3,558 kilometers) just to get to the processing plant. As the local-food movement has come of age, this concept of "food miles" (or "-kilometers")--roughly, the distance food travels from farm to plate--has come to dominate the discussion, particularly in the United States, the United Kingdom, and parts of Western Europe.
The concept offers a kind of convenient shorthand for describing a food system that's centralized, industrialized, and complex almost to the point of absurdity. And, since our food is transported all those miles in ships, trains, trucks, and planes, attention to food miles also links up with broader concerns about the emissions of carbon dioxide and other greenhouse gases from fossil fuel-based transport.
In the United States, the most frequently cited statistic is that food travels 1,500 miles on average from farm to consumer. That figure comes from work led by Rich Pirog, the associate director of the Leopold Center for Sustainable Agriculture at Iowa State University (he is also behind the straw-berry-yogurt calculations referenced above). In 2001, in some of the country's first food-miles research, Pirog and a group of researchers analyzed the transport of 28 fruits and vegetables to Iowa markets via local, regional, and conventional food distribution systems. The team calculated that produce in the conventional system--a national network using semitrailer trucks to haul food to large grocery stores--traveled an average of 1,518 miles (about 2,400 kilometers). By contrast, locally sourced food traveled an average of just 44.6 miles (72 kilometers) to Iowa markets.
In light of such contrasts, the admonition to "eat local" just seems like common sense. And indeed, at the most basic level, fewer transport miles do mean fewer emissions. Pirog's team found that the conventional food distribution system used 4 to 17 times more fuel and emitted 5 to 17 times more C09 than the local and regional (the latter of which roughly meant Iowa-wide) systems. Similarly, a Canadian study estimated that replacing imported food with equivalent items locally grown in the Waterloo, Ontario, region would save transport-related emissions equivalent to nearly 50,000 metric tons of [CO.sub.2] or the equivalent of taking 16,191 cars off the road.
But what exactly is "local food" in the first place? How local is local?
One problem with trying to determine whether local food is greener is that there's no universally accepted definition of local food. alisa Smith and J.B. MacKinnon, authors of The 100-Mile Diet, write that they chose this boundary for their experiment in eating locally because "a 100-mile radius is large enough to reach...