Earlier [in October], a storm front swept across the Great Plains of the United States, plowing up a wall of dust that could be seen from space…. It was a scene straight from the Dust Bowl of the 1930s, when farmers regularly saw soil stripped from their fields and whipped up into choking blizzards of dust.
…. According to a new study, dust storms on the Great Plains have become more common and more intense in the past 20 years, because of more frequent droughts in the region and an expansion of croplands. “Our results suggest a tipping point is approaching, where the conditions of the 1930s could return,” says Gannet Haller, an atmospheric scientist at the University of Utah ….
The dust storms not only threaten to remove soil nutrients and decrease agricultural productivity, but also present a health hazard, says Andy Lambert, a co-author on the study and a meteorologist at the U.S. Naval Research Laboratory in Monterey, California. The dust contains ultrafine particles that can penetrate cells in the lungs and cause lung and heart disease.
The findings, reported on 12 October in Geophysical Research Letters, show that across large parts of the Great Plains, levels of wind-blown dust have doubled over the past 20 years. One clue that agriculture is responsible is that the dust levels tend to peak during spring and fall—planting and harvesting seasons, Hallar notes.