University of Wisconsin–Madison
photo of an irrigated corn field

Food system vulnerability

Food security: warming, water availability, and abrupt shifts in crop yield

Climate change threatens US food security and economies. The US agriculture system is the world’s largest producer of maize and soybean. Research has already demonstrated that warming and frequent extreme heat can be detrimental to production through increasing evapotranspiration. Therefore, increasing pressure may be put on irrigation to maintain high productivity. However, yield trends have stagnated in some regions, suggesting that agriculture will not be able to keep pace with a rapidly growing global population. With concerns already surrounding unsustainable water management practices to produce food, climate change could exacerbate water use problems, and could force new policies that impact agricultural production.
In the US, we identify three at-risk regions where irrigation is a mainstay, the Central Valley of California, the Great Plains, and the Central Sands region of Wisconsin, and ask such questions: 1) Has yield growth stagnated in some regions due to climate change, or will it likely stagnate due to limited water resources? 2) Where and for what crops might the demand for water be escalating, and are there tipping points at which production might be significantly affected? 3) How will crop demand for water change with projected future changes in climate, and will we see regime shifts that are dependent on region and/or crop type? With historical weather data and downscaled climate model (GCM) data, we assemble USDA databases on annual agricultural productivity with agroecosystem models to evaluate how climatic changes affect agricultural yield and test if there are abrupt changes existing in agricultural ecosystems and what are their driving forces.