The heat waves that powered the Dust Bowl are now more than twice as likely to happen again

They were called "black blizzards" and "black rollers," towering billows of dust rising thousands of feet high that became ominous symbols of the catastrophic Dust Bowl that hit the United States during the 1930s. Sweeping across the Great Plains, these choking storms reduced visibility to less than three feet and, upon reaching the East Coast, blotted out the sun and erased from view prominent landmarks such as the Statue of Liberty and the U.S. Capitol Building.

"It has been a terrible week, with one day of almost complete obscurity, and others when only a part of the sun's rays struggled through the gloom with a strange bluish luminance," wrote one farmer in 1936. "On such days each little wave of the troubled water in the stock tank glitters with a blue phosphorescent light. When I dip out a pail of water to carry to the hen-house, it looks almost as if it were covered with a film of oil."

All told, the Dust Bowl and the black blizzards it spawned triggered drought and erosion across more than 100 million acres of America's agricultural heartland, stretching from Montana to Texas. While overgrazing and intensive farming practices laid the foundation for the ecological disaster, record-setting heatwaves in 1934 and 1936 — with the latter still the hottest ever recorded — provided the critical tipping point.

According to study just published in the journal Nature Climate Change, a Dust Bowl-like heat wave is now more than twice as likely to happen in the U.S. each century due to climate change.

"These record-breaking events in 1934 and 1936 occurred perhaps once every hundred years, but with present day greenhouse gases they reduced to about one in every 30 or 40 years," Tim Cowan, a research fellow at the University of Southern Queensland and the report's lead author, told Forbes.

Buying time with groundwater

If farming practices since the Dust Bowl have prevented another from happening, why should we be so concerned about the coming decades? According to the study, widespread use of groundwater irrigation by farmers has effectively kept a lid on black blizzards from appearing in modern times.

"Groundwater is used quite extensively across the U.S., and we know, from previous research, that increased irrigation and agricultural intensification has led to cooler summer maximum temperatures," Cowan told CBS News.

With groundwater depletion already occurring and vast regions of the western U.S. already locked in what's described as the first human-caused megadrought, it's likely only a matter of time before the luck that has kept us sheltered from another Dust Bowl runs out. "Even though you have better practices in cropping now, the rises in temperature reduce those benefits, so there would still be a negative impact," Cowan added.

The research team concludes that only reductions in both greenhouse gas emissions and groundwater use will help stem future instances of horizons streaked black with towering dust clouds. Warning that such events as the 1936 heat wave could become "the new normal," study co-author Gabi Hegerl, professor of climate system science at the University of Edinburgh, told Forbes that the next decades will likely eclipse anything since.

"With summer heat extremes expected to intensify over the US throughout this century, it is likely that the 1930s records will be broken in the near-future," she said.