Food-Miles and the Relative Climate Impacts of Food Choices in the United States

• Published in: Environmental science & technology 2008-05, Vol.42 (10), p.3508-3513
• Main Authors: Weber, Christopher L, Matthews, H. Scott
• Format: Article
• Language: English
• Subjects: Applied sciences; Climate; Emissions; Environmental impact; Environmental science; Exact sciences and technology; Food; Food Supply; Greenhouse effect; Life cycles; Pollution; Transportation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es702969f

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.