GWAC article for the Lexington Minuteman 8/8/08
Will 'Thinking Global, Eating Local' Reduce Your Carbon Footprint?
Among the most important things you can do personally to reduce your personal greenhouse gas emissions are to drive and fly less (much, much less!) and make sure your home is as energy-efficient as possible. Transportation is responsible for about a third of global warming emissions, and home operations (energy use, construction, and water and sewage) make up another third.
But you also eat—probably several times a day. What contribution do your food choices make to global warming? Well, overall, food is responsible for 12 percent of consumers' total global warming impact, which is a lot less than the bite taken by driving and home energy use, but still considerable.
Recently, people have been paying a lot of attention to "food miles" (how far food travels from its source to your plate). As a blanket statement, researchers have found that food in general has traveled more than 1,500 food miles to reach you!
However, that number doesn't hold up too well under closer examination. For one thing, there's no such thing as an "average" food. What do a head of lettuce and a side of beef have in common, other than being edible?
Also, here in the Northeast, during our long, relatively cold winters, we have virtually no access to locally grown produce. A tomato grown in a heated greenhouse in Maine in January could very well rack up more carbon emissions than one shipped from California, although it has traveled a tenth of the food miles to your local store.
And what does “local” mean anyway? In July, stores in Massachusetts and New Hampshire start selling 'local' corn from New Jersey. That's at least a few hundred miles away from most of us.
A study published this spring by researchers at Carnegie Mellon University compared global warming impacts of many food types. They found that transportation as a whole represents only 11 percent of the total greenhouse gas emissions of food throughout its "life." Many other things affect the global warming impacts of food, including farm management techniques (e.g., soil tilling, pesticide and fertilizer use, handling of waste products), and especially shipping methods and water requirements.
Okay, so now you're really frustrated and ready to quit reading altogether, right? But wait! There is, in fact, something you can do that will have a significant, clearly documented, across-the-board effect to reduce carbon emissions. What is it?
Eat Less Red Meat and Dairy Products.
That's all. Nothing complicated about it. No need to check where an animal was raised, what it was fed, or whether the cheese was from organic milk. Just eat less beef, pork, lamb, and dairy foods.
This is the conclusion of the Carnegie Mellon researchers, who said: “We suggest that dietary shift can be a more effective means of lowering an average household's food-related climate footprint than 'buying local.” Shifting less than one day per week's worth of calories from red meat and dairy products to chicken, fish, eggs, or a vegetable-based diet achieves more GHG reduction than buying all locally sourced food."
In fact, they calculated that a completely local diet (pretty hard to do in New England) would reduce a household's greenhouse emissions by an amount equivalent to driving a 25-mpg car 994 fewer miles per year, whereas switching off red meat just one day a week would spare 1,155 miles of driving.
Producing red meat and dairy products requires enormous energy inputs—so much so that total food miles for the entire supply chain account for only 6 percent of the GHG emissions for red meat and for dairy. For beef, water and land use up the most energy--about five times that of rice and twice that of chicken.
On the other hand, sticking to local foods grown in their natural season has significant advantages. One estimate says that local food purchased at a farmers market travels an average of just 63 miles. (If you already eat "low on the food chain," buying food locally, or possibly growing some of your own, will have a greater impact proportionally.) There are also many other reasons to love local foods, among them helping small Northeast farmers to survive in a wildly competitive environment, helping to retain open space, the security of knowing where your food came from, and fresher, more flavorful foods. (See "The Economics of Buying Local" in this issue.)
So don't sweat the details too much, but DO substitute more vegetables, fruits, and grains for meat and dairy products, and support your community by buying local products in season.
This week’s column is guest authored by Susan Altman, Massachusetts Climate Action Network (MCAN)
Brought to you by Lexington Global Warming Action Coalition. Contact us at www.lexgwac.org