The global food system is on track to become one of the biggest casualties of climate change — even as farmers adapt, new research warns.
A large-scale study, published in Nature, found that for every additional degree Celsius of global warming, the world’s agricultural capacity will shrink by the equivalent of 120 fewer calories per person per day — about 4.4% of today’s global average consumption.
“When global production falls, consumers are hurt because prices go up and it gets harder to access food and feed our families,” says author Professor Solomon Hsiang from the Stanford Doerr School of Sustainability. “If the climate warms by 3 degrees, that’s basically like everyone on the planet giving up breakfast.”
If emissions continue rising unchecked, global yields could fall 24% by 2100.
Drawing on real-world observations from over 12,000 regions in 55 countries, the researchers analysed the productivity and adaptability of the six crops that form the backbone of human diets: wheat, corn, rice, soybeans, barley, and cassava.
They found that farmers are already responding to the shifting climate — planting different crops, changing sowing dates, and adjusting inputs like fertiliser. But those adaptations can only go so far.
Even in the best-case scenarios, the team estimates that adaptation will offset just one-third of global yield losses by the end of the century.
“Any level of warming, even when accounting for adaptation, results in global output losses from agriculture,” says author Andrew Hultgren, an agriculture and consumer economics expert at the University of Illinois Urbana-Champaign.
According to the modelling, if emissions continue rising unchecked, global yields could fall 24% by 2100. Even if the world rapidly cuts emissions to net zero, crop production is still expected to drop by 11%.
In the U.S. Midwest, for example, current corn and soybean powerhouses are particularly vulnerable. “They just get hammered under a high-warming future,” Hultgren says.
Rice was the only crop that showed a possible upside: because it thrives in warmer nighttime temperatures, there’s a 50% chance global rice yields might increase in a hotter world. But for the other five crops, the chance of yield declines by century’s end ranges from 70% to 90%.
With the planet already around 1.5°C hotter than pre-industrial levels, farmers are seeing the early warning signs: longer droughts, off-season heatwaves, and unpredictable rain are eroding yields, even as they invest in better fertilisers, irrigation, and seed varieties.
Because carbon dioxide lingers in the atmosphere for centuries, the study finds little difference in projected losses by 2050, no matter how quickly emissions fall. By then, climate change is expected to drag global yields down by around 8%.
Beyond crop productivity, previous research has also shown how elevated CO₂ reduces crop nutrition, bringing a whole slew of additional problems.
The research team is now helping policymakers identify where adaptation efforts can be most effective. That includes access to weather forecasts, improved fertiliser, and basic infrastructure — resources many smallholder farmers still lack.
“Farmers know how to maintain the soil, invest in infrastructure, repair the barn,” says Hsiang. “But if you’re letting the climate depreciate, the rest of it is a waste. The land you leave to your kids will be good for something, but not for farming.”