They concluded that it would be more effective in reducing GHG emissions to change the diet of consumers than to buy local foods.

Christopher Weber, one of the researchers, comments, "There is more [total] greenhouse gas impact from methane and nitrous oxide than from all the CO2 in the supply chain.” [Environmental Science & Technology: “Do food miles matter?”]

The paper “Food-Miles and the Relative Climate Impacts of Food Choices in the United States” is published in the journal Environmental Science & Technology (Environ. Sci. Technol., 42 (10), 3508–3513, 2008. 10.1021/es702969f).

Christopher L. Weber and H. Scott Matthews are from the Department of Civil and Environmental Engineering and the Department of Engineering and Public Policy at Carnegie Mellon University (Pittsburgh, Pennsylvania, U.S.A.). The paper was published at the EST website on April 16, 2008.

In the  May 24, 2008 article “For food’s ecological impact, meat means more than miles” in Science News (page 11), Rich Pirog, associate director of the Leopold Center for Sustainable Agriculture (Iowa State University, Ames, Iowa, U.S.A.) stated, “There are many good reasons for going local. But this study is important. Food miles alone are not a reliable indicator of environmental impact.” (Pirog is not associated with the research study.)

Weber adds his advice (which he says has been given for generations), “Eat a healthy balanced diet, with a minimum of processed food. Eat a moderate amount of dairy and meat. Eat more whole grains and veggies. Following that advice will probably reduce your carbon footprint." [Science News]