“Refrigerated food” is a net win or loss for climate emissions
Few inventions have had a greater impact on our daily lives, and especially on the food we eat, than refrigeration. But there are still places in the world, such as sub-Saharan Africa, where an unbroken refrigerated supply chain, or “cold chain,” that keeps perishable food cold from farm to market is not yet reality.
To researchers who study how various human activities affect the production of climate-altering greenhouse gases, the introduction of a cold chain into a region offers the opportunity to examine an understudied tradeoff:
Refrigeration reduces food losses significantly, but it’s an energy-intensive process responsible for an estimated 1 percent of the world’s total greenhouse gas emissions. On balance, do the increased emissions from cold-chain operation outweigh the emissions avoided due to reduced food loss?
Two University of Michigan researchers used computer models to simulate the introduction of an integrated, refrigerated food supply chain into sub-Saharan Africa. They concluded that greenhouse gas emissions tied to the operation of a North American-style cold chain would be about 10 percent greater than the food-loss emissions avoided.
“We looked at whether or not the greenhouse gas emissions associated with running a refrigerated supply chain are offset by expected reductions in food loss. Unfortunately, they’re not,” said Shelie Miller of the U-M Center for Sustainable Systems, co-author of a paper published online Dec. 19 in the journal Environmental Science & Technology.
“The message on the direct impacts of refrigeration is pretty clear. When you’re looking strictly at the technology itself, the cold chain adds more greenhouse gases than it saves,” said Miller, an associate professor at the School for Environment and Sustainability and director of the U-M Program in the Environment. First author of the paper is U-M doctoral student Brent Heard.
In the modeling study, Miller and Heard looked at scenarios where both North American and European-style cold chains are introduced into the post-harvest food system in sub-Saharan Africa, creating additional emissions through the use of refrigerants and electricity while reducing food spoilage.
The greenhouse-gas emissions required to get one kilogram of refrigerated food to retail outlets was estimated in seven food categories: cereals, roots and tubers, fruits, vegetables, meat, fish and seafood, and milk. The study examined only the pre-consumer or “upstream” portion of the food-supply chain.