A huge dust storm moves across the land during the Dust Bowl of the 1930s. (Image: USDA)

New research shows that a repeat of 1930s drought conditions would be comparably destructive to US crops, despite modern agricultural techniques. The news gets considerably worse in light of climate change.

A new study published in Nature Plants demonstrates the surprisingly damaging effects of a 1930s-type drought on current US crops, and the impacts of global warming on agriculture in the years to come. Researchers Michael Glotter and Joshua Elliot from the University of Chicago ran computer simulations to predict the effects of a Dust Bowl-like drought on today’s maize, soy, and wheat crops.

“We expected to find the system much more resilient because 30 percent of production is now irrigated in the United States, and because we’ve abandoned corn production in more severely drought-stricken places such as Oklahoma and west Texas,” noted Elliott in a press release. “But we found the opposite: The system was just as sensitive to drought and heat as it was in the 1930s.”

Image: USDA

The Dust Bowl crisis was caused by three distinct droughts that struck in quick succession, in 1930-31, 1933-34, and 1936. Wheat yields declined at a staggering rate during this period, including losses of 32 percent in 1933. The drought caused severe hardship to Americans living in the Great Plains region, eroding land value, kicking up devastating dust storms, and displacing millions of people.

Agricultural practices have changed extensively since the 1930s, but not necessarily with an eye to the future and the potential for changing or more extreme climatic conditions. Crops are now optimized to be bountiful instead of resilient, leaving many staple crops vulnerable to droughts and high temperatures.

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By simulating the effects of the 1936 drought on today’s agriculture, Glotter and Elliot observed 40 percent losses in maize and soy yield, and 30 percent declines in wheat—numbers comparable to the Dust Bowl crisis. The predicted harm would be about 50 percent worse than the drought of 2012, which caused nearly $100 billion of damage to the US economy.

“Technology has evolved to make yields as high as possible in normal years,” said Glotter. “But as extreme events become more frequent and severe, we may have to reframe how we breed crops and select for variance and resilience, not just for average yield.”

When the researchers factored in climate change, the situation went from bad to worse. With each degree of temperature increase, yield losses increased by 25 percent. An increase of four degrees above today’s average temperatures (a possible scenario by mid-century) reduced crop yields by as much as—brace yourselves—80 percent over the course of an entire season. And this is exclusive of drought conditions. Even with normal amounts of rainfall, this hotter weather is expected to result in losses as bad as those experienced in the 1930s.

It’s difficult to know what will happen to US crops in the event of a double-whammy drought and temperature boost, but the word “catastrophe” certainly comes to mind. Given recent predictions that parts of the US could soon experience “megadroughts” lasting for as long as 35 years (yes, you read that correctly), these results should serve as a serious wakeup call.

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In addition to reducing greenhouse gas emissions, the authors of the new study recommend developing new strains of crops with higher heat tolerance, shifting towards more drought-resistant crops (such as sorghum), and migrating wheat, soy, and maize agriculture to northern US states. These measures will undoubtedly cost a lot of money, but the eventual cost of inaction is practically incalculable.

[Nature Plants]