Crops that account for half the world’s calories will struggle to adapt to climate change

Grasses like wheat and rice won’t be able to adapt in time, according to a new study.

CREDIT: ISTOCK/YGREK
CREDIT: ISTOCK/YGREK

More bad news for climate change and agriculture: A new study has found that the rate of climate change is likely to outpace the ability for key staple crops, like rice, corn, or wheat, to adapt.

Together, these crops account for almost half of the world’s calories, raising concerns that climate change could lead to nutritional shortages around the world.

Researchers from the University of Arizona looked at 236 species of grass — which included crops like wheat, maize, rice, and sorghum — and compared their ability to adapt to and successfully grow in changing environments with the forecasted climate conditions for 2070. If climatic shifts change the niche climate for crops — the particular environment in which that crop thrives — crops can survive by either moving to another location or evolving to thrive in the changed environment.

For grasses, however, the researchers found that in most instances, the grasses were not able to adapt to a different environment as quickly as the pace of climate change. In some instances, the climate change outpaced the grasses’ adaptation 20,000-fold.

Grasses also can’t move easily, because grasses don’t spread their seeds readily over long distances.

The study only looked at wild crops, not cultivated species used in conventional agriculture, but the researchers said that the results could easily apply to cultivated crops as well.

“The findings are similar across all the groups so they could be applied to wild species as well as to the cultivated ones,” John Wiens, co-author of the study and professor of ecology and evolutionary biology at the University of Arizona, told BBC News. “There is no way that cultivated species are somehow exempt from our findings.”

This is hardly the first study to find a connection between climate change and staple crops. A 2014 study found that 2 degrees Celsius of warming could seriously damage yields for crops like wheat, rice, and maize, if those species are unable to adapt to changing climate conditions — something that this study argues is unlikely. By the end of the century, the study argues, decreases in crop yields could be as high as 25 percent.

One way to help crops adapt to climate change is by exploring the genetic diversity of the crop contained in wild crop relatives, which are the species of cultivated crops that have not been domesticated for agriculture. But while those species often grow in more strenuous climatic conditions — thriving in areas that are warmer or drier than conventional crops — the University of Arizona study shows that wild crops are perhaps equally slow at adapting to shifting climate environments as their cultivated relatives. Moreover, a study released earlier this year warned that crucial crop wild relatives aren’t adequately protected in seed banks, which are supposed to protect crop biodiversity from calamitous events like floods, earthquakes, war, or climate change.