Your Green Review

Inundated with messages to ‘Buy Local!’ and ‘Buy American!’ in order to save the environment and decrease ‘food miles’, consumers are flooding farmers markets, CSA’s and co-ops. And with U.S. produce traveling an average of 1,500 miles from farm to grocer, it would seem that the ‘Buy Local’ phenomenon makes sense in the movement towards sustainable agriculture. Or does it? While it’s true that (local) small scale farms may be more likely to practice sustainable farming, the environmental premise behind buying local to reduce greenhouse gas (GHG) emissions falls short.

A study conducted by engineers Christopher Weber and H. Scott Matthews of Carnegie Mellon University found that the transportation of food from farm to grocer accounted for only 4% of the food industry’s GHG emissions. Through a series of life cycle studies it was determined that 83% of the typical American household’s food-related carbon footprint results from the production phase and not from final phase transportation or food miles. From the use of fertilizer to processing methods and other energy/resource consumption, GHG emissions (CO2 and non-CO2) are more heavily influenced by our food-group choices than how far it’s traveled.

Some foods, like fruits and vegetables, tend to be less energy and resource depleting and contribute a relatively small percent of GHG to overall industry emissions. However, accounting for a whopping 30% of total emissions due to soil management techniques, manure management and enteric fermentation, red meat tops the study’s list of greenhouse-intensive foods. Ruminant animals, especially cows, are responsible for 37% of all human-related methane emissions (methane being 23 times as warming as C02). The study estimates that a 21-24% reduction in red meat consumption, replaced by chicken, fish or eggs, can offset the same amount of GHG as a totally localized diet.

But consumers must be discerning even when it comes to the local variety. Despite conventional wisdom, local production can, in some cases, be detrimental to surrounding ecologies. Dumping excessive resources into the production of food items not suited for a particular climate or environment can quickly deplete a region’s supply of natural resources with little return on the investment. Case in point: 20% of California’s developed water supply is diverted to produce alfalfa (a water-intensive crop) in the desert. 70% of the state’s harvest is used locally as feed for dairy cattle in California’s largest agricultural industry. While transport-related CO2 emissions may be lessened, growing such a water dependent crop in an area experiencing serious water shortages is contributing to an environmental and social crisis for an approximate return of about 30 cents a day (National Resource Defense Council).

In short, native foodstuffs are best bought at home where they can thrive without much coaxing. But if a product generates more waste when grown locally than it would by being shipped 1,500 miles or requires absurd amounts of resources to support its production, then we need to either rethink our food choice or rethink where we choose to purchase it. We have a greater capacity to facilitate change-as individuals and as a society-in a shift towards conscientious consumption where the entire life cycle of our food is taken into account and underlying habits driving GHG emissions are modified.

Read More:

NPR. Food Footprint. Minimizing GHG (Radio Interview):

http://www.npr.org/templates/story/story.php?storyId=89808292

FAO Newsroom. Livestock, a Major Threat to Environment (Article):

http://www.fao.org/newsroom/en/news/2006/1000448/index.html

UN News Center. Rearing Cattle Produces More GHG Than Driving Cars (Article):

http://www.un.org/apps/news/story.asp?NewsID=20772&Cr=global&Cr1=environment