"A majority of food's climate impact is due to non-CO2 greenhouse gases," the team wrote. Their findings appear online this week in the journal Environmental Science & Technology. Dairy products come in second in greenhouse impact in most of the team's analyses, since they also come from cows. Cereals and carbohydrates; chicken, fish and eggs; and fruits and vegetables were similar to each other in their contributions. Armed with this information, the team calculated that shifting roughly a quarter of the 240 red meat calories the average American eats a day to chicken, grains or fruits and vegetables would have the same effect as going completely local. Of course, if you are already eating mostly veggies and grains, cutting out the transportation component by choosing local food won't hurt. However, Weber cautioned, other studies have looked at the greenhouse gas impacts of individual foods like tomatoes and apples and found that long-term refrigerated storage or greenhouses may be required for even local supplies, which may create energy demands that balance or exceed that needed to transport the same foods from friendlier climes. "There are other advantages to going local," said Pamela Martin of the University of Chicago, who has also studied the greenhouse gas footprint of the food supply. "There are also local economic benefits and food security issues." Her preliminary research suggests that greenhouse gas emissions from fertilizers and pesticides outweigh transportation emissions. The importance of transportation may be different in other countries, added Weber. In the U.K., a larger fraction of food arrives by plane, emitting more CO2. Emissions will also vary locally, depending on how far one is from coastal ports or train lines. Related Links: |
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