Half of the world’s population could face severe food shortages by the end of the century as rising temperatures take their toll on farmers’ crops, scientists have warned.
Harvests of staple food crops such as rice and maize could fall by between 20 percent and 40 percent as a result of higher temperatures during the growing season in the tropics and subtropics. Warmer weather in the region is also expected to increase the risk of drought, cutting crop losses further, a new study shows.
The worst of the food shortages are expected to hit the poor, densely inhabited regions of the equatorial belt, where demand for food is already soaring because of a rapid growth in population.
A study in the US journal Science found there was a 90 percent chance that by the end of the century, the coolest temperatures in the tropics during the crop growing season would exceed the hottest temperatures recorded between 1900 and 2006.
More temperate regions such as Europe could expect to see previous record temperatures become the norm by 2100.
“The stress on global food production from temperatures alone is going to be huge, and that doesn’t take into account water supplies stressed by the higher temperatures,” said David Battisti, at the University of Washington, who led the study.
Battisti and Rosamond Naylor, at Stanford University in California, combined climate models from the Intergovernmental Panel on Climate Change (IPCC) and historical examples of the impact of heatwaves on agriculture, and found severe food shortages were likely to become more common.
Naylor, who is director of food security and the environment at Stanford, said the study emphasized the need for countries to invest in adapting to a changing climate. To develop new crops to withstand higher temperatures could take decades, she added.
The tropics and subtropics, which stretch from the southern US to northern Argentina and southern Brazil, from northern India and southern China to southern Australia, and cover all of Africa, are currently home to 3 billion people. Future temperature rises are expected to have a greater impact in the tropics because crops grown there are less resilient to changes in climate.
“When all the signs point in the same direction, and in this case it’s a bad direction, you pretty much know what’s going to happen,” Battisti said.
“You’re talking about hundreds of millions of additional people looking for food because they won’t be able to find it where they find it now,” he said. “You can let it happen and painfully adapt, or you can plan for it. You could also mitigate [climate change] and not let it happen in the first place, but we’re not doing a very good job of that.”