The United States is largely self-sufficient in agricultural food production, supported by extensive storage capacity and a well-developed system of interstate trade. However, the growing frequency and intensity of extreme weather events are placing increasing strain on agriculture, raising concerns about the country’s ability to sustain food production for an increasing population. These pressures highlight the importance of a resilient food supply chain that can withstand climate-related shocks.

A new study from the University of Illinois Urbana-Champaign examines how extreme weather in one part of the country can affect agricultural trade and food manufacturing far beyond the areas directly impacted. Published in the Proceedings of the National Academy of Sciences, the research analyses state-to-state trade flows for agricultural products to show how local climate shocks propagate through national supply chains.

“With climate change, we’re going to experience more intense and more frequent extreme weather events such as drought and flooding, which impact agricultural output,” said lead author Hyungsun Yim, a doctoral student in agricultural and consumer economics. “It’s important to prepare for ways to mitigate climate shocks to food manufacturing.” Sandy Dall’erba, a professor in the same department and founding director of the Center for Climate, Regional, Environmental and Trade Economics, co-authored the study.

According to Dall’erba, the research is the first to systematically map how extreme weather in individual states reduces local agricultural yields and then affects food manufacturing nationwide through interstate trade. For example, a severe drought in Midwestern grain-producing states can disrupt supply chains and influence production in central food manufacturing states such as California, Texas, Illinois, and New York.

Although the US produces roughly 80 to 85 per cent of the food it consumes domestically, this self-sufficiency depends heavily on internal trade and transportation networks. Around 57 per cent of grain production and 77 per cent of livestock output are used as inputs for domestic food manufacturing rather than being sold directly to households. This interdependence makes the system vulnerable to regional climate shocks, even when national production remains relatively strong.

To analyse these dynamics, the researchers combined two decades of data on interstate trade flows with detailed weather information on temperature, precipitation, drought, and excess wetness. One key example was the 2012 Midwestern drought, which sharply reduced grain output in Iowa, Illinois, and Nebraska. These states typically account for about 34 per cent of the US grain trade, but their share fell significantly that year. As a result, Nebraska increased imports to support its livestock sector, while Texas shifted grain sourcing to states such as Kansas, Oklahoma, and Louisiana. Prices for wheat, maize, and soybeans rose by up to 20 per cent, affecting food manufacturers nationwide.

Overall, the study found that a one per cent increase in drought intensity in producing states reduces domestic agricultural exports by 0.5 to 0.7 per cent, leading to an average decline of 0.04 per cent in food manufacturing output. While this downstream effect is relatively small, it reflects both the resilience of the US agrifood system and the need for planning. The authors argue that their findings can help guide investments in infrastructure, storage, transportation, and multi-state coordination to better prepare for future climate shocks.

More information: Hyungsun Yim et al, Impact of extreme weather events on the US domestic supply chain of food manufacturing, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2424715122

Journal information: Proceedings of the National Academy of Sciences Provided by University of Illinois College of Agricultural, Consumer and Environmental Sciences