One topic that has gotten some attention in 2008 is “food miles”, or the estimate of the environmental impact of the total resource use and transportation required to get food from grower to consumer. One argument for eating more locally-produced food is that it reduces the transportation impact; however, in making that argument we also have to take into account differentials in total factor productivity. In other words, if your local farmers are less productive than distant farmers, producing and consuming a given amount of food produced locally could increase resource use because the local farmers have less of a comparative advantage and achieve lower yields. That increased resource use mitigates the transportation benefits of local production, and if large enough can outweigh them entirely.
At Aguanomics David Zetland had a post recently with some links to work on the “carbon footprint of food”; interestingly, one report finds that transportation constitutes a small share of food’s environmental impact, and that most of food’s climate impact is a result of non-carbon dioxide greenhouse gases (such as methane). Very interesting.
Back in November Ron Bailey wrote about food miles at Reason, and I’ve been wanting to post about it since then. He mentions the studies that David noted in his recent post, and Ron also commented on a Mercatus Center study of the food miles argument (pdf).
In their recent policy primer for the Mercatus Center at George University, however, economic geographer Pierre Desrochers and economic consultant Hiroko Shimizu challenge the notion that food miles are a good sustainability indicator. As Desrochers and Shimizu point out, the food trade has been historically driven by urbanization. As agriculture became more efficient, people were liberated from farms and able to develop other skills that helped raise general living standards. People freed from having to scrabble for food, for instance, could work in factories, write software, or become physicians. Modernization is a process in which people get further and further away from the farm. …
Food miles advocates fail to grasp the simple idea that food should be grown where it is most economically advantageous to do so. Relevant advantages consist of various combinations of soil, climate, labor, capital, and other factors. It is possible to grow bananas in Iceland, but Costa Rica really has the better climate for that activity. Transporting food is just one relatively small cost of providing modern consumers with their daily bread, meat, cheese, and veggies. Desrochers and Shimizu argue that concentrating agricultural production in the most favorable regions is the best way to minimize human impacts on the environment.
In other words, the productivity effects on resource use swamp the resources used and emissions generated in the transportation portion of the supply chain. Incorporating this aspect of productivity into the food miles argument illustrates the point I raised above — much of what determines resource use and emissions in the food supply chain is factor productivity and comparative advantage.