As global warming has been up on the agenda this week, I believe many of you will find the following synopsis of a recent study on the impact of food-miles on CO2 emissions quite interesting. The study is from two pioneers in the field of environmental life-cycle analysis at Carnegie-Mellon University in Pittsburgh. [Note: This study is presented from a US perspective, however its main conclusions can easily be applied to other developed countries.]
As you are most likely aware, “food miles” refer to the distance food travels from farm to plate, are a simple way to gauge food’s impact on climate change. The simplicity of this approach has been recognized by commentators (likely from its birth), and several other recent studies had already poked holes in the “food mile” concept. However, this new study is one of the first (if not the first) comprehensive study to look at the end-to-end (life-cycle) processes and identifies where the largest CO2 producers lie in the process.
Essentially, it’s how food is produced, not how far it is transported, that matters most in the production of CO2. The study shows that transportation creates only 11% of the greenhouse gases that an average U.S. household generates annually as a result of food consumption. However, the agricultural and industrial practices that go into growing and harvesting food are responsible for 83% of the greenhouse gas emissions. In other words, eating locally may not make a difference and could even be a worse alternative. As an example, it can be more energy efficient for a British household to buy tomatoes or lettuce from Spain than from heated greenhouses in the UK, although it has been pointed out that eating food flown on an airplane is almost certainly a losing proposition; for those of us from Canada, this problem can only be exacerbated during our winters. Of particular interest, the study notes that a relatively small dietary shift (i.e., once of twice a week) can accomplish about the same greenhouse gas reduction as eating locally (food for thought?).
Finally, the study also notes that eating less red meat and dairy can be a more effective way to lower CO2 emissions than buying local food (Jeremy – Per your request this morning…).
While the study is only available for a price, you can get a more detailed synopsis at: