A new study shows dust storms have become more common and more severe on the Great Plains, leading some to wonder if the United States is headed for another Dust Bowl, reports Roland Pease for Science. With nearly half the country currently in drought and a winter forecast predicting continued dry weather for many of the afflicted regions, dust storms could become an even bigger threat.

In the 1930s, the Dust Bowl was caused by years of severe drought and featured dust storms up to 1,000 miles long. But the other driving force behind the plumes of dust that ravaged the landscape was the conversion of prairie to agricultural fields on a massive scale—between 1925 and the early 1930s, farmers converted 5.2 million acres of grassland over to farming, reported Sarah Zielinski for Smithsonian magazine in 2012.

Hardy prairie grasses would have likely withstood the drought, but crops covering the newly converted tracts swiftly bit the proverbial dust, which loosened the grip their roots had on the soil. High winds then whipped that loose soil into the huge clouds that blanketed the landscape with dust, including 1935’s Black Sunday which lifted 300,000 tons of the stuff skyward.

Besides blotting out the sun, dust storms strip valuable nutrients from the soils, making the land less productive, and create a significant health hazard at a time when a respiratory illness is sickening people around the world, according to Science.

dust graphic
A graphic representing the hazards of increasing atmospheric dust. (Talie Lambert)

The new research, published earlier this month in the journal Geophysical Research Letters, used data from NASA satellites and ground monitoring systems to detect a steady increase in the amount of dust being kicked into the atmosphere every year, reports Brooks Hays for United Press International. The researchers found that levels of atmospheric dust swirling above the Great Plains region doubled between 2000 and 2018.

According to the paper, the increasing levels of dust, up to five percent per year, coincided with worsening climate change and a five to ten percent expansion of farmland across the Great Plains that mirrors the prelude to the Dust Bowl. Together, the researchers suggest these factors may drive the U.S. toward a second Dust Bowl.

“We can’t make changes to the earth surface without some kind of consequence just as we can’t burn fossil fuels without consequences,” says Andrew Lambert, a meteorologist at the U.S. Naval Research Laboratory and the paper’s first author, in a statement. “So while the agriculture industry is absolutely important, we need to think more carefully about where and how we plant.”

Part of what allowed Lambert and his colleagues to tie the added dust in the sky to agriculture were clear regional upticks when and where major crops such as corn and soybeans were planted and harvested, per the statement. Ironically, much of the grassland that was converted to agriculture in recent years was not for food but for corn destined to become fodder for biofuels intended to reduce reliance on fossil fuels, Lambert tells Science.

Human-caused climate change is also making the Great Plains hotter and drier. In April, a paper published in the journal Science said the Southwestern part of North America may be entering a megadrought worse than anything seen in 1,200 years.

“The current drought ranks right up there with the worst in more than a thousand years, and there’s a human influence on this of at least 30 percent and possibly as much as 50 percent in terms of its severity,” as Jason Smerdon, a paleoclimatologist at Columbia University’s Lamont Doherty Earth Observatory who co-authored the study, told Smithsonian magazine’s Brian Handwerk at the time.

Just last week, a large dust storm struck eastern Colorado, reports Jesse Sarles for CBS Denver.

“I think it’s fair to say that what’s happening with dust trends in the Midwest and the Great Plains is an indicator that the threat is real if cropland expansion continues to occur at this rate and drought risk does increase because of climate change,” Lambert says in the statement. “Those would be the ingredients for another Dust Bowl.”