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Which crops are most vulnerable to climate change, and in which places? 

Crops that thrive in very specific environments will face the toughest odds as climate change advances, but even the relatively resilient crops we rely on most—like wheat, corn and rice—will be affected. 

 

October 23, 2024

Today, people around the world get more than half of their calories from just three crops: rice, corn, and wheat.1 So what will happen as climate change alters the weather and soil conditions in which we grow them? 

Big cereal crops are actually relatively resilient to climate changes, says David Des Marais, a professor of civil and environmental engineering at MIT. In the U.S., they’re grown in huge fields in the middle of the country. As the world gets hotter, they can relatively easily move northward, where they can find temperatures they’re well-suited for. 

Still, cereal crops are vulnerable to changing conditions. Those crops have been bred to be relatively genetically uniform. That makes them the “Ferrari” of growing in their current environments, says Des Marais, but they may not be as high-performing in new landscapes. 

In the future, climate change will play with yields in different locations, with big economic consequences. Even if crops can migrate, local economies will suffer, because farmers will need to switch to new staple crops. Certain areas may lose their agricultural economy altogether.2 Already, we’re seeing climate change slow the rise in wheat yields in parts of Asia, Australia, South America and the Caribbean, and Southern and Western Europe.3 Rice production has been hindered in North America. And corn and soy yields have suffered in Latin America.4 Most of these declines, says Des Marais, are due to low rainfall, higher temperatures, or a combination of the two. 

Corn (maize) may be especially vulnerable, because high temperatures at the wrong time of year can cause the plant to abort seeds during reproduction. In addition, corn sees very little benefit from the “CO2 fertilization effect,” which allows many plants, including wheat and rice, to grow faster as carbon dioxide in the air rises. Since rising CO2 levels are the main driver of climate change, this effect has offset some of the harms of rising temperatures and extreme weather—but not for corn.5

Geographically, tropical countries, many of which already have high temperatures and variable rainfall, are likely to be more impacted—especially those with the fewest resources to adapt their agricultural practices. Sub-Saharan Africa and Central and South America, for instance, stand out in many studies of crop vulnerability.6 

The more we warm the Earth, the harder it will become to estimate the effects on crop yields. Future projections for heat, drought, and intense rainfall all become more uncertain as climate change progresses, and crop growth depends on interactions between all these variables.7 But we can be confident that the faster we act to control our climate pollution, the less agriculture will be disrupted.

Absent that kind of serious action, cereal crop prices could increase substantially by 2050,6 bringing a growing risk of food shortages. “It’s going to take a combined effort of breeders, agronomists, and supply chain experts to maintain the yields we’re accustomed to,” says Des Marais.

And not all plants have the luxury of migrating to friendlier climates. The crops that are most likely to struggle with climate change are those that require highly specific conditions—in terms of light, soil and temperature—to flourish. 

“They're what crop breeders would call landraces, or local varieties,” says Des Marais. “For centuries or millennia, these have been bred in a local setting to do well in that particular climate and that particular soil type and with specific management strategies.”

Those crops may include tomato and potato varieties raised by Indigenous people in the Andes, or okra cultivated by Native Nations in the U.S.8 Even stone fruits like peaches, plums and cherries—which are sensitive to chilly temperatures as well as high heat—may have a hard time adapting.9 “It's the ones that are really relied on by local communities or small regions that we're probably going to see the biggest losses from,” says Des Marais. 

Reducing our CO2 emissions in order to slow or stop climate change would help these plants survive. But there is another way to keep these various crops from being “orphaned,” says Des Marais. “There's no reason that any of these crops have to go extinct,” he says. Seed banks, which already exist in many places, can stow seeds away for planting in new areas where better climate conditions may exist. Seed banks can even be useful in protecting the big cereal crops, he adds, by letting us hold onto diverse varieties of these crops in case some are more resilient to future changes.  

Des Marais also recommends learning from traditional farming practices, which often featured more types of crops on the same land, letting farmers respond more quickly as conditions changed. “'I’m optimistic that we'll be able to solve a lot of this food crisis by looking backwards a little bit and not thinking about this as this technological problem to be solved, but rather a system that can be more adaptive than I think it has been in recent history.”

 

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Footnotes

1 Awika, Joseph M, "Major cereal grains production and use around the world." ACS Publications, Volume 1089, 2011, doi:10.1021/bk-2011-1089.ch00.

2 Rising, James and Naresh Devineni, "Crop switching reduces agricultural losses from climate change in the United States by half under RCP 8.5." Nature Communications, Volume 11 2020, doi:10.1038/s41467-020-18725-w. 

3 Advances in agricultural technology, and its continuing spread around the world, mean that overall crop yields continue to rise. Studies of the impacts of climate change on crop yields typically show results relative to a world without climate change.

4 Intergovernmental Panel on Climate Change: "Chapter 5: Food, Fibre, and other Ecosystem Products." In: Climate Change 2022: Impacts, Adaptation and Vulnerability. Working Group II Contribution to the IPCC Sixth Assessment Report.

5 Tigchelaar, Michelle, et al., "Future warming increases probability of globally synchronized maize production shocks." Proceedings of the National Academy of Sciences, Volume 115, Number 26, 2018, doi:10.1073/pnas.1718031115

6 Intergovernmental Panel on Climate Change: "Food Security." In: IPCC Special Report on Climate Change and Land, 2019.

7 Rezaei, Ehsan Eyshi et. al., "Climate change impacts on crop yields." Nature Reviews Earth & Environment, Volume 4, 2023, doi:10.1038/s43017-023-00491-0.

8 Ramirez-Villegas, Julian et. al.,"State of ex situ conservation of landrance groups of 25 major crops." Nature Plants, Volume 8, 2022, doi:10.1038/s41477-022-01144-8.

9 U.S. Department of Agriculture Climate Hubs: "Climate Vulnerabilities of California Speciality Crops." Accessed October 23, 2024.