Food miles are a measure of how far food travels between its production and its eater. An in-season carrot at the local farmers market travels only a few miles, while out-of-season carrots may come from another continent. Transportation requires energy, and as oil energy becomes scarce it is increasingly expensive to support a global food supply chain.
Two years ago, I wrote an manifesto criticizing America’s industrial agriculture in part on the unsustainable cost of transportation.
Chain supermarkets offer discount prices on grocery items. This is possible because the chain is able to purchase food products at volume discounts from suppliers and wholesalers; these savings are then passed on to customers. To support this structure, chains use regional distribution to pass inventory along to individual locations. That is, an apple goes from a farm to a distribution center, to a truck, to the loading dock of a store, and finally to the display case and a customer’s shopping cart. This organization has led to an unsustainable structure in which the average American meal travels thousands of miles before arriving at a dinner plate.
A parallel argument is carbon footprint. Fossil fuels release carbon into the atmosphere, contributing to climate change. I never used this claim specifically, but I did take some solace in buying locally-sourced steak as an environmentally-friendly choice.
A 2008 study in the Journal of Environmental Science and Technology challenges this point.
Despite significant recent public concern and media attention to the environmental impacts of food, few studies in the United States have systematically compared the life-cycle greenhouse gas (GHG) emissions associated with food production against long-distance distribution, aka “food-miles.” We find that although food is transported long distances in general (1640 km delivery and 6760 km life-cycle supply chain on average) the GHG emissions associated with food are dominated by the production phase, contributing 83% of the average U.S. household’s 8.1 t CO2e/yr footprint for food consumption. Transportation as a whole represents only 11% of life-cycle GHG emissions, and final delivery from producer to retail contributes only 4%. Different food groups exhibit a large range in GHG-intensity; on average, red meat is around 150% more GHG-intensive than chicken or fish. Thus, 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.
If you’re trying to reduce your carbon footprint, the takeaway is clear — eating less meat is more effective than eating local. I suggest you try both.
Why does meat have a big impact?
Meat has a greater impact on carbon output because:
- Animals produce greenhouse gas emissions.
- Industrial animal farms release huge amounts of environmental waste.
- Ten calories of energy input are required for every one calorie of energy output in meat production. Animals have to be fed before they can feed you, and feed has transportation costs associated with it as well.