The carbon footprint of cold chain food flows in the United States

The food system is an important contributor to carbon dioxide emissions. The refrigerated food supply chain is an energy-intensive, nutritious, and high-value part of the food system, making it particularly important to consider. In this study, we develop a novel model of cold chain food flows between counties in the United States. Specifically, we estimate the truck transport via roadways of `meat' and `prepared foodstuffs' for the year 2017. We use the roadway travel distance in our model framework rather than the great-circle distance between two locations to improve the estimate of the long-haul freight with temperature controlled system. This enables us to more accurately calculate the truck fuel consumption and CO2 emissions related to cold chain food transport. We find that the cold chain transport of `meat' emitted 8.4x10^6 T CO2 yr-1 and `prepared foodstuffs' emitted 14.5x10^6 T CO2 yr-1, which is in line with other studies. `Meat' has a longer average refrigerated transport distance, resulting in higher transport CO2 emissions per kg than processed foodstuffs. We also find that CO2 emissions from cold chain food transport are not projected to significantly increase under the temperatures projected to occur with climate change in 2045. These county-level cold chain food flows could be used to inform infrastructure investment, supply chain decision making, and environmental footprint studies.