A combination of climate change and unsustainable agricultural practices could lead to Dust Bowl–like conditions
- By Christian Elliott on
The thick dust cloud formed in minutes, engulfing part of Interstate 55—Illinois’s main thoroughfare between Saint Louis and Chicago—in blizzardlike whiteout conditions on May 1. Drivers slammed on their brakes but not quickly enough. Car after car collided, leaving seven dead and the mangled remains of 72 vehicles lining both sides of the highway.
For a tragedy like this to occur in the Midwest, a perfect storm of factors must come together, says National Weather Service meteorologist Chuck Schaffer, who tracked the imposing wall of dust on satellite imagery. In this case, straight-line winds swept across crop fields near the interstate just after farmers plowed them, loosening topsoil that was left unusually dry by weeks without rain. That combination of circumstances doesn’t happen often, which means that dust storms are rare in Illinois. But researchers warn that with the effects of climate change and the ever expanding agricultural industry, such storms could be a growing problem across the Great Plains and Midwest. That concern has even led some scientists to consider whether the country’s heartland is tumbling into a new Dust Bowl. The original Dust Bowl in the 1930s was the worst drought in U.S. history, which caused unprecedented dust storms and devastated agriculture.
“These were storms that eroded hundreds of millions of pounds of topsoil and spread dust as far as New York City,” says Benjamin Cook, a climate scientist specializing in land surface change and drought at NASA’s Goddard Institute for Space Studies. The intensification of agriculture—tilling prairie to plant corn and wheat—helped drive the original Dust Bowl, Cook has shown in his research. In the wake of the calamity, the government’s Soil Conservation Service took major steps to improve practices that had degraded the soil. Farmers now rely heavily on irrigation to keep dust under control. But experts say today’s conventional agriculture practices still leave soil at risk.
“Conventional agricultural practices are super intense,” says Evan Thaler, a researcher at Los Alamos National Laboratory, who specializes in agricultural soil erosion in the Midwest. “They’re out there plowing a bunch for weed control and for soil moisture control, and what happens is that soil gets really nice and fluffy and easy to erode by water and wind.” And during the winter, when plants aren’t growing, the soil is left bare and exposed. Thaler and his colleagues have calculated that over the past 160 years, a third of the dark topsoil that made the Midwest famous for farming has eroded.
The impact of farming on dust has also been seen more widely. In a recent study, Gannet Hallar, an atmospheric scientist at the University of Utah, and her then graduate student Andrew Lambert found atmospheric dust levels across the Great Plains increased by 5 percent per year between 2000 and 2018—that’s nearly a doubling of dust in two decades. The increases coincide with areas that farmers converted from grassland to cropland over that period. Dust concentrations were highest during spring planting and fall harvesting.
And agriculture is still expanding. Policies pushing biofuel production are driving farmers to convert even lands that are less agriculturally productive into fields to grow corn for ethanol, and those lands then generate more dust, Hallar says. Only a tenth of a percent of the prairie that held the soil together for centuries in Illinois, the “Prairie State,” remains today. More broadly, less than 4 percent of North America’s original tallgrass prairie still exists unplowed. Even some land returned to prairie through the U.S. Department of Agriculture’s Conservation Reserve Program (CRP) has been converted back to cropland. “It’s more lucrative to have even poorly performing crops in marginal areas, compared to what the USDA pays for CRP land,” Thaler says.
Climate change is likely exacerbating the dust problem in some places, as alterations in weather patterns bring less rainfall and high temperatures dry out soils faster. “Most of the western United States has been locked in almost continuous drought for the last 20 years,” Cook says. There and in the Great Plains, “if we see continued increases in aridity and drought, as we expect with climate change, we’ll start to see further increases in dust loads in the atmosphere.” Scientists are actively studying dust hotspots near highways in the Southwest and have identified the Great Plains and the Midwest as regions to watch.
While much of the West, Southwest and Great Plains are getting drier under climate change, Illinois is generally set to get wetter, with more frequent heavy precipitation events and localized flooding. Yet the amount of dust is still increasing. Hallar’s data show the south-central region of the state where the May storm originated is getting dustier by about 2 percent per year. That points to the role agriculture is playing there and puts the onus on the government to incentivize better farming practices, Thaler says. One option to keep dust down is no-till agriculture, which uses a specific planter that drills seeds into the ground in tiny furrows, eliminating the need to plow the soil. Another is cover cropping, which involves planting crops such as oats or hairy vetch during the winter so fields never lay bare and exposed.
“In conjunction, those two methods have been shown to decrease erosion by something like 95 percent,” Thaler says. There is an opportunity for Congress to include incentives for sustainable agriculture practices in the Farm Bill, which is up for renegotiation this year, though Thaler is not confident that will happen. “At the end of the day,” he says, “it’s all about policy.”
Encouraging such practices and continuing irrigation could help prevent a Dust Bowl on the scale of the 1930s disaster, Cook says. Hallar agrees. “I would say this is an emerging trend that we should be really concerned about,” she says. “Is it going to get as bad as the Dust Bowl? That, we can’t say. But it’s something we should all be aware of and paying attention to.”
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ABOUT THE AUTHOR(S)
Christian Elliott is a science and environmental journalist based in Chicago. Follow Elliott on Twitter @csbelliott or visit his website at christianelliott.me.