June 10, 2008 —
There are plenty of benefits to buying your food locally or growing it yourself: supporting small farmers and businesses in your community, keeping your food genetically unmodified and pesticide-free, better taste, and of course there's the satisfaction that comes along with a DIY lifestyle. But one of the arguments for living "locavore" has recently come under attack from several economists who began studying the issue a few years ago.
"Why," many asked, "do we fly lettuce from Mexico to New York, when it could be grown less than 20 miles from the restaurants where it's being served?" In today's world, the answer to any question about any business motive usually involves profit margins and supply chain efficiency, but environmentalists have long questioned whether these considerations should take priority over carbon emissions. And thus, the locavore movement was born, and in the past few years, with concern about global warming rising as fast as carbon levels in the atmosphere, it's been pretty popular of late.
But the underlying assumption about buying local—that cutting the final transportation distance of a food item will necessarily reduce the carbon emissions associated with its consumption—appears to be flawed. According to Stephen J. Dubner, author of the bestseller "Freakanomics" and it's sister-blog on NYTimes.com, preliminary research into the matter has failed to show a correlation between a local diet and a low-carbon diet.
Dubner cites a recent article in Environmental Science and Technology that attributes only 11 percent of a food's greenhouse gas emissions to transportation, with less than half of those emissions coming from the final trip between the farm it was grown on and your plate. In fact, according to the same article, eating less than one day's worth of red meat a week, would actually have a greater impact on a family's carbon footprint than eating 100 % locally sourced foods.
It's obviously going to be a long time before carbon emissions accounting becomes an exact science, but so far, the evidence does not support the importance of local foods in cutting greenhouse gases.