Rising global temperatures are set to devastate food crops across the world, with particularly alarming impacts projected for the United States, where production of key crops could plummet 50% by the end of the century, according to a sweeping new analysis.
Of the many impacts of the fossil fuel-driven climate crisis, damage to the global food system is one of the most terrifying. But the overall impact of climate change on crops — and how much it can be offset by farmers’ adaptations — has been hard to establish and hotly debated.
The new analysis, eight years in the making, is “the first attempt to really tackle both of those problems,” said Solomon Hsiang, a study author and professor of global environmental policy at the Stanford Doerr School of Sustainability.
The scientists analyzed six crops — maize, soybeans, rice, wheat, cassava and sorghum — in more than 12,000 regions across 54 countries. Together, these crops provide more than two thirds of humanity’s calories.
They also measured how real-world farmers are adapting to climate change, from changing crop varieties to adjusting irrigation, to calculate the overall impact of global warming.
Their findings are stark. Every 1 degree Celsius the world warms above pre-industrial levels will drag down global food production by an average of 120 calories per person per day, according to the study, published Wednesday in Nature.
This will push up prices and make it harder for people to access food, Hsiang said.
“If the climate warms by 3 degrees, that’s basically like everyone on the planet giving up breakfast,” he said. The world is currently on track for around 3 degrees Celsius of warming by the end of the century.
Wheat, soy and maize — high value crops for a lot of the world — will be especially badly affected, the study found.
If humans keep burning large amounts of fossil fuels, maize production could fall by 40% in the grain belt of the US, eastern China, central Asia, southern Africa and the Middle East; wheat production could fall by 40% in the US, China, Russia and Canada; and soybean yields could fall 50% in the US.
The only staple crop that might be able to avoid substantial losses is rice, which can benefit from warmer nighttime temperatures.
One of the striking findings of the study is that some of the wealthiest countries are likely to be hardest hit.
Poorer parts of the world, where climate conditions are already fairly harsh, tend to be more adapted and better prepared for the impacts of the climate crisis, Hsiang said. Agricultural systems in breadbaskets such as the US and parts of Europe, however, are optimized for the current temperate climate, he said.
Global warming will be particularly devastating for the US, where it’s projected to reduce yields by 40% to 50% for all staple crops except rice, Hsiang said.
“Places in the Midwest that are really well suited for present day corn and soybean production just get hammered under a high warming future,” said study author Andrew Hultgren, an assistant professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign. “You do start to wonder if the Corn Belt is going to be the Corn Belt in the future.”
Lower-income countries won’t escape effects, however. Yields of the subsistence crop cassava will fall in sub-Saharan Africa as the world heats up, a substantial threat to nutrition for some of the world’s poorest people, the study found. “One reason people grow cassava is because it’s pretty robust to droughts, but we see that it is actually still very adversely affected by extreme heat conditions,” Hsiang said.
Shelby McClelland, a researcher specializing in climate change and agriculture at New York University who was not involved in the research, said the study reveals the importance of adaptation but also its limits. “The authors show that current adaptation decision-making is insufficient to ensure future food security,” she told CNN.
Erin Coughlan de Perez, an associate professor at Tufts University who specializes in climate risk management, said one of the study’s limitations is that it does not take into account two major climate adaptations: crop switching or changes to planting dates. In the US, for example, corn and soybean crops have moved northward. These changes could offset more climate impacts, she told CNN.
Ultimately, the findings add to a long list of alarming research about the global food system, said Tim Lang, professor emeritus of food policy at City St George’s, University of London.
“The data pile up. The politicians turn a blind eye… Land use is not altering fast or radically enough. Some pioneers do their best. But the net effect is that the global wriggle room diminishes,” he told CNN.
Hsiang hopes the study will provide more evidence for the urgent need to transform the energy system and the high costs of failing to doing so.
“This is a major problem. It’s incredibly expensive. As a species, we have never confronted anything like this.”
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