Stanford researchers say climate models missed key signs in Europe and China.
More frequent hot weather and drier air are taking a toll on global crop production, particularly for staple grains like wheat, barley and maize, according to a new study from Stanford University. Published in Proceedings of the National Academy of Sciences, the analysis found that warming and drying trends have intensified across nearly every major agricultural region.
“There have been a lot of news stories about crop failures around the world, and often I get asked whether the impacts are happening faster than we expected,” said David Lobell, lead author and director of Stanford’s Center on Food Security and the Environment. “That motivated a closer look at what’s been happening in farms around the world.”
The research estimates that global yields of barley, maize and wheat are currently 4% to 13% lower than they would have been without recent climate trends. In many cases, those losses have outweighed any benefits from elevated atmospheric carbon dioxide, which can boost photosynthesis and plant growth.
“In many ways, the changes farmers are experiencing are completely in line with what climate models predicted, so the overall impact should not be a surprise,” said Stefania Di Tommaso, co-author and research data analyst at the center.
But the study also revealed two major surprises: In temperate zones such as Europe and China, observed increases in air dryness far exceeded model projections. Conversely, in the U.S. Midwest, the warming and drying have been milder than anticipated.
“These two big surprises are important to resolve,” Di Tommaso said. “Of all the uncertainties in climate models, these are the two big ones that matter for global food production.”
The study emphasized that errors in modeling don’t just affect predictions — they also skew adaptation strategies. For instance, efforts to lengthen growing seasons by planting longer-maturing crop varieties may now be at risk because those same regions are drying out faster than expected.
The findings support earlier concerns raised in a March study that warned U.S. agricultural productivity could slow sharply without greater investment in climate adaptation. Together, the research points to an urgent need for more accurate forecasting tools and smarter, region-specific responses.
“Overall, I think climate science has done a remarkable job of anticipating global impacts on the main grains, and we should continue to rely on this science to guide policy decisions,” Lobell said. “If anything, I think the blind spots have been on specialized crops where we don’t have as much modeling, but which are very salient to consumers.
“That includes things like coffee, cocoa, oranges and olives. All these have been seeing supply challenges and price increases. These matter less for food security but may be more eye-catching for consumers who might not otherwise care about climate change.”
Lobell added that part of the public’s surprise may come from misplaced expectations.
“I think when people hear 5%, they tend to think it’s a small number,” he said. “But then you live through it and see it’s enough to shift markets. We’re talking about enough food for hundreds of millions of people.”
