California’s processing tomato industry, valued at $1 billion, is expected to experience minimal postharvest losses due to rising temperatures and traffic congestion, according to a study from the University of California, Davis. The research was published in the American Journal of Agricultural Economics and examined 1.4 million truckloads of tomatoes transported from farm fields to processing facilities between 2011 and 2020.
Sarah Whitnell, who led the research as a postdoctoral scholar at UC Davis and is now with the University of Western Australia in Perth, said: “It’s rare that we find an example where climate change is expected to have a negligible effect. Ultimately, the supply chain is a well-oiled machine. The losses are relatively small, and while temperature does increase them, it’s not by a huge amount.”
The researchers matched each truckload with state highway traffic data and hourly temperature readings ranging from 48 degrees to 108 degrees Fahrenheit. They compared truckloads from the same field within the same growing season under different conditions—for example, one transported early in the morning when it was cooler and traffic was lighter versus another moved later in the day when both heat and congestion were higher.
According to Whitnell: “If you have this magic scenario where temperatures are cool but there is traffic, you actually have the lowest losses. This is because faster speeds cause vibrations that can increase damage in fresh produce.”
The study found that under worst-case conditions—hot weather combined with heavy traffic—the proportion of damaged tomatoes (soft, split or squished) doubled from about 1% to 2%. However, these remain modest losses for such a large-scale operation.
Tim Beatty, chair of the Department of Agricultural and Resource Economics at UC Davis and senior author on the paper, noted: “Most supply chains aren’t nearly as efficient as the California supply chain, so what this says is if you’re a very efficient supply chain, you can mitigate the losses associated with climate change. It says that adaptation is possible to really reduce loss past the farm gate.”
Beatty also highlighted that while most climate change research focuses on agricultural production itself rather than postharvest stages—where most farm revenue is generated—this study used comprehensive public data along with detailed industry-supplied information on transport logistics and product quality.
“We know very little about the effects of climate change once product leaves the farm gate,” Beatty said. “I think this paper is one of the very first to actually tackle that.”
The research received support from the U.S. Department of Agriculture’s Agriculture and Food Research Initiative.
