Beans: they’re not fruit (technically, they’re legumes) but when it comes to feeding a growing, warming world, they might be magical. One of the world’s oldest staple crops, beans provide cheap, stable protein for some 400 million people in the developing world. Until recently, scientists worried that the food security provided by beans could be threatened by climate change, as global temperature rise would decimate world bean populations.
Now, they’ve got 30 reasons for optimism, as researchers at CGIAR, a global food research consortium, recently announced the discovery of new, heat-resistant beans that can survive even under the worst-case scenarios for global warming. In experiments, these 30 bean strains were able to tolerate nighttime temperatures of up to 72 degrees Fahrenheit, about 7 degrees warmer than the common bean can usually handle.
“Even if [the heat-tolerant beans] can only handle a 3 degree [Celsius] rise, that would still limit the bean production area lost to climate change to about five percent,” Steve Beebe, a senior CGIAR bean researcher, said in a press release.
Traditionally, beans are grown in places where nighttime temperatures stay below 64-degrees Fahrenheit. Because beans pollinate themselves during the night, and pollination is incredibly sensitive to temperature change, night temperatures are a valuable indicator of a bean’s ability to withstand temperature fluctuations.
Previous studies warned that by 2050, climate change could threaten 50 percent of land suitable for growing beans. For places like Latin America and Africa — where beans are an especially critical source of nutrients — the disappearance of farmland capable of growing beans endangers basic food security. Scientists also estimate that to keep up with a growing world population, food production will need to increase by 60 percent by 2050, which means that losing half of the world’s bean production would be dire for the world’s food security.
The new bean varieties — or “lines,” as plant breeders call them — are the result of cross-breeding between popular lines of beans, like the pinto or the white bean, with less popular strains, like the tepary bean. The tepary bean, grown mostly by indigenous communities in the American Southwest, is a particularly hardy bean, showing resistance to both heat and drought. But it’s also small and low-growing, causing it to often be overlooked by bean farmers.
According to NPR, Colombian scientist Alvaro Mejia-Jimenez was one of the first to try and blend the heat resistant properties of the tepary with more common bean varieties. In the late-1990s, Mejia-Jimenez succeeded, growing a hybrid bean by fertilizing a common bean flower with pollen from a tepary bean plant. After a few generations, Mejia-Jimenez had created a line of bean that could grow on its own.
Mejia-Jimenez’s work sat largely unnoticed for years, until an alarming report warned of the extensive damage rising temperatures might have on world bean production. Hoping to find varieties of beans that could withstand a warming world, researchers at the International Center for Tropical Agriculture (CIAT) went looking through the thousands of bean strains that they keep in stored in seed banks (part of CIAT’s mission is to safeguard the genes of vital staple crops, like beans and cassava). They tested the beans in controlled plots along Colombia’s Caribbean coast, as well as in greenhouses, where researchers could adjust the temperature at will.
One variety of the heat-resistant beans researchers found through their testing is currently being grown in Costa Rica, and farmers are seeing double the yields of traditional beans.
“What this shows us is that heat may already be hurting bean production in Central America far more than we thought and farmers could benefit from adopting the new heat-beater beans right now,” Beebe said.