- By Prerna MankadPrerna Mankad is a researcher at Foreign Policy.
Increasing global demand for food along with biofuels production has meant that rising food prices have been hitting our paychecks hard. But the news will likely only get worse.
In a recently released National Bureau of Economic Research paper, Wolfram Schlenker of Columbia University and Michael J. Roberts of the U.S. Department of Agriculture reveal the effects of climate change on crop yields in the United States. The results are alarming: According to Schlenker and Roberts’s model, which employs data on crop yields in the United States between 1950 and 2004 along with a matching weather/temperature data set, yields are likely to diminish significantly by the end of the century.
Although yields for corn and soybeans increase until temperatures reach about 29° Celcius and yields for cotton increase until about 33° Celcius, temperatures above these thresholds result in a rapid and steep decline thereafter. Global warming is expected to shift temperatures upward and produce more damaging heatwaves. As a result, Schlenker and Roberts predict that corn yields will decrease by 44 percent, soybean yields will drop by 33-34 percent, and cotton yields will decline by 26 to 31 percent — and that’s just under the "slow warming" scenario of the model. If the model assumes "quick warming," the news is even more dire. Corn, soybean, and cotton yields will plummet by 79-80 percent, 71 to 72 percent, and 60 to 78 percent respectively.
To make matters worse, "hotter southern [U.S.] states exhibit the same threshold as cooler states in the north, suggesting there is limited potential for adaptations." In other words, the prospect of crops evolving quickly to adapt to a warmer environment looks slim. Technology, too, appears unlikely to save the day just yet. The authors conclude, "[W]e find no evidence that technological progress increased heat tolerance over the last 55 years: while average yields have gone up almost threefold, the breakpoint where temperatures become harmful is the same in later periods as it is in earlier periods." As the Earth gets hotter, expect inflation to soar. Time to stock up on corn, soybean, and cotton products.