Comparing environmental impacts of regional and national-scale food supply chains: A case study of processed tomatoes

•We modeled life cycle impacts of regional and national-scale food supply chains.•Regional crop production advantages can compensate for impacts of longer shipping.•Highly concentrated products are energy intensive but amplify regional advantages.•Mode of transport greatly affects life cycle impacts of food supply chains.•Organic methods reduced field production impacts and increased processing impacts. This study uses life cycle assessment methodology to quantify the energy use, greenhouse gas (GHG) emissions, and water use of processed tomato products grown, processed, and consumed within the Great Lakes region of the United States, and tomato products produced in California and then shipped to the Great Lakes region for consumption. The purpose is to assess the potential for regional food systems to reduce selected environmental impacts, particularly the energy and GHG footprints, of consumer-ready, processed food products, when compared to national-scale food systems in which consumer products are shipped long distances. The study also examines the role of different types of food processing in influencing life cycle energy use, water use, and emissions. Our results indicate that California-produced conventional and organic tomato paste and canned diced tomatoes are almost equivalent in energy use and GHG emissions to regionally produced and consumed products, but use of developed water resources is significantly higher for California-grown products. California tomato production benefits from higher per hectare yields and soil amendments with lower carbon dioxide emissions. These efficiencies substantially offset the added energy use and GHG emissions associated with long-distance shipment of products to the Great Lakes region, as long as shipments are made by rail rather than by truck. Paste, the more processed and concentrated product evaluated, amplifies any environmental advantages or disadvantages accrued in the field production stage, due to its raw tomato to finished product ratio of 6:1, suggesting that comparative regional advantage can play a role in lowering life cycle environmental impacts of highly condensed foods shipped long distances.