Buying Local Won't Save Us?

Local food devotees, hold onto your seats — your ideas are in for a challenge. A new report from the USDA's Economic Research Service (ERS) compares small-scale-local to industrial food supply chains. Notably, the study found that the amount of fuel used for transportation is more closely related to the size and efficiency of the supply chain than to the distance the food travels. This means that food delivered via truck from a local farm might actually be using up more fuel and doing more damage to the environment than food shipped halfway around the world in an 18-wheeler.

Products grown on small farms get transported in much smaller loads, oftentimes in old, inefficient vehicles, which might bring the fuel use per unit up higher than it is for huge loads of things shipped long distances in relatively fuel-efficient vehicles. The USDA summary page states that, "In these cases, greater fuel efficiency per unit of product is achieved with larger loads and logistical efficiencies that outweigh longer distances."

Advocates of the modern sustainable food movement place so much emphasis on reducing the distance from farm to plate that the point about the inefficiencies of local food, though only one of the many conclusions in the report, should not go understated. While building up local food resources is indeed good for the health and vitality of local communities and economies, shipping small batches of things to farmers' markets from relatively nearby isn't a panacea to our carbon-emissions problems.

The report, titled “Comparing the Structure, Size, and Performance of Local and Mainstream Food Supply Chains,”is composed of a series of related case studies that include interviews, site visits with farms and businesses, and secondary data. The studies look at the way in which food gets from farms to consumers in 15 food supply chains, comparing these processes to mainstream supply chains on a number of factors.

So what’s the conclusion to be drawn about local food? Quite simply, the distance food travels is only one factor in its impact on our environment. The picture is quite a lot more complicated than local vs. non-local.

In one good example, think about the use of water. Is it better to advocate that water be shipped into dry areas like the Southwest to grow things locally than it is to grow the food in temperate areas where water is abundant and then ship the finished goods using efficient distribution systems? The sooner we as advocates and consumers start understanding these complexities, the sooner we can start finding practical solutions for the large-scale picture of our agricultural system.

An extensive discussion of food miles’ role in food’s environmental impact can be found in the book Just Food by James E. McWilliams, which I strongly encourage anyone espousing the local-food paradigm to read. His premise — that reducing food miles is not the cure-all that many claim it to be — is based on the fact that multiple analyses of food-product life cycles have found transportation to almost always account for a rather minor amount of the energy used in getting food from field to fork. The vast majority of energy is used at various stages of the production of crops — harvesting, for example — and a surprisingly large amount of energy goes into its preparation in inefficient home kitchens.

“In focusing on food miles at the expense of so many other detrimental factors of production and consumption, we’re wasting time, energy, and a heap of good intentions that could very well save future generations from the mess that previous generations have dumped on us," McWilliams writes in the book.

He argues that there are things we can do — from changing production practices to making in-home cooking more efficient — that would reduce the energy used in the process much more than cutting down on food miles. Unfortunately most of these types of changes — farmers sharpening equipment properly or changing elements of their equipment to make harvesting more efficient, for example — are things that are beyond consumers' control. But the important point is that we need to start talking about how tactics beyond locavorism must come into play in order to improve our food system.

Photo: stevendamron via Flickr