Warmer climate will dramatically increase the volatility of global corn crops
Corn, or maize, is the most widely grown crop in the world. Used in food, cooking oil, industrialized foods, livestock feed and even automobile fuel, the crop is one that both rich and poor people rely upon.
Research led by the University of Washington looks at what climate change will mean for global yields of this crop. The results show that warmer temperatures by the end of this century will reduce yields throughout the world, confirming previous research. But the study also shows dramatic increases in the variability of corn yields from one year to the next and the likelihood of simultaneous low yields across multiple high-producing regions, which could lead to price hikes and global shortages.
The study was published the week of June 11 in the Proceedings of the National Academy of Sciences.
“Previous studies have often focused on just climate and plants, but here we look at climate, food and international markets,” said lead author Michelle Tigchelaar, a UW postdoctoral researcher in atmospheric sciences. “We find that as the planet warms, it becomes more likely for different countries to simultaneously experience major crop losses, which has big implications for food prices and food security.”
In the wake of a recent UW study looking at the nutritional value of rice cropsunder climate change, this study addressed overall yields and price volatility of corn.
While most rice is used domestically, corn is traded on international markets. Four countries—U.S., Brazil, Argentina and the Ukraine—account for 87 percent of the global corn exports (China mostly produces for domestic use). Today the probability that all four exporters would have a bad year together, with yields at least 10 percent below normal, is virtually zero.
But results show that under 2 degrees Celsius warming, which is projected if we succeed in curbing greenhouse gas emissions, this risk increases to 7 percent. Under 4 degrees Celsius warming, which the world is on track to reach by the end of the century if current greenhouse gas emissions rates continue, there’s an 86 percent chance that all four maize-exporting countries would simultaneously suffer a bad year.
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