Rich Pirog, associate director of the Leopold Center at Iowa State University and one of the pioneers of the concept of "food miles."

May 9, 2015

Rich Pirog, associate director of the Leopold Center at Iowa State University and one of the pioneers of the concept of "food miles," is the first to concede that it's smarter to assess the environmental impact of a food item over its entire lifetime. That means looking not only at transportation impacts but also those of production and distribution. But not a few commentators have gone further, suggesting food miles do not matter at all. For example, Dr Adrian Williams of the National Resources Management Centre at Cranfield University, told reporters for the Guardian newspaper in the United Kingdom ("The Observer," 23 March 2008): "The concept of food miles is unhelpful and stupid. It doesn't inform about anything except the distance traveled." Pirog has just pointed out to me three recent studies, however, which underscore that food miles still matter enormously. The first study comes from the University of Washington in Seattle. It compares two plates with identical amounts of salmon, potato, asparagus, and apple. One is locally produced; the other isn’t. The researchers perform a Life Cycle Assessment (LCA) on each plate, and find that the nonlocal plate contributed 50% more of the greenhouse gases (GHG) responsible for climate disruption than the local plate did. ("Seattle Food System Enhancement Project: Greenhouse Gas Emissions Study.") Interestingly, salmon dominates both sides of the analysis because fishermen – local and nonlocal, for aquaculture and wild catch – use prodigious amounts of diesel fuel. Even so, what ultimately tips the climate scales against the nonlocal plate is transportation. The study found foreign producers of fruits and vegetables are slightly more efficient in their use of chemicals and farm fuels, but the transportation of the nonlocal plate produces six times more GHG than transportation for the local plate. Overall, the nonlocal fruits and vegetables produced nearly two times as much GHG as the local alternatives. Somewhat different conclusions come from a team of researchers at the Catholic University in Leuven, Belgium. ("Energy Lifecycle Inputs in Food Systems: A Comparison of Local versus Mainstream Cases," Journal of Environmental Policy & Planning, March 2007.) The study finds that local food systems can produce more greenhouse gases than mainstream food systems. For example, if local means a household makes a car trip to a community supported agriculture farm several times each week, rather than one trip to a supermarket, the associated energy consumption is relatively high. But the Belgian study also suggests the best GHG strategy is to localize intelligently. Walk or ride a bike when you go shopping. Choose food products that are in season (and avoid GHG burdens of heated greenhouses). Plan ahead to minimize storage and packaging


Source: Michael Shuman, Small-Mart, Ideas and Tools for Building Healthy, Local Communities, April 24 2008,

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