Global warming could hurt crop yields significantly

Comparison of statistically estimated effects
of temperatures on observed and simulated
U.S. yields in rainfed counties

Rising temperatures caused by climate change could greatly reduce U.S. crop yields of corn, wheat and soybeans, says a study by researchers at Germany's Potsdam Institute for Climate Impact Research, published in Nature Communications.

Researchers found that without efficient emission reductions, U.S. farmers could suffer yield losses of 50 percent for corn, 40 percent for soybeans and 20 percent for wheat by 2100. Bernhard Schauberger, lead author of the study, said: "Projections tell us that in the U.S., these crops will suffer from hotter days. Since these days will get more frequent with climate change, there will be harvest losses."

Researchers came to their conclusions through computer simulations, Kavya Balaraman reports for Climatewire. "According to their estimates, corn and soybean plants can lose 5 percent of their harvest for every single day that is recorded above 30 C (86 F). Such crop losses could have huge repercussions for domestic food security and—given that the U.S. is one of the largest crop exporters in the world—affect prices in the international market."

The main problem is that hotter days lead to higher water evaporation rates, Balaraman writes. "Moreover, plants tend to open their stomata—small pores on their leaves—to transpire water when temperatures increase, creating an additional source of stress. Certain studies have also suggested that high temperatures during a plant's flowering period could actually lead to a 'sterilization' effect . . . The problem is exacerbated in areas like Kansas and West Texas that are entirely reliant on groundwater resources."