Less Dust (And More Hurricanes) With Warming
The decrease in dust could also improve air quality in west Africa.
Dust blowing out of the Sahara Desert spreads all over the planet, even reaching the poles, and alters weather patterns.
But scientists now say that the Sahara will generate less dust over the next century, as a result of global warming's influence on wind patterns.
Among other things, reduced dust could help lead to increased hurricane formation in the Atlantic Ocean.
In a study published in the journal Nature, a team of American and French researchers, used a computer simulation of wind patterns to analyze Saharan dust over a 160-year period, from 1851 to 2011. They found that the airborne dust goes through cyclic periods of high and low concentrations.
The highest concentrations occurred from the 1910s to the 1940s and the 1970s to the 1980s. There also have been several low-concentration periods, in the 1860s, 1950s and 2000s.
When the researchers projected wind patterns onto climate models, they found they predicted a statistically significant downward trend in African dust emission and transport as greenhouse emissions increase in the course of the 21st Century. That's because global warming would cause a slowdown of tropical wind circulation.
That atmospheric feedback would enhance warming of the tropical North Atlantic, which would make the basin more suitable for hurricane formation and growth.
But the dust decrease also could have some beneficial environmental effects, the researchers said. For example, it might lead to improved air quality in west Africa.
Saharan dust has wide-ranging effects upon the planet. It contains nutrients that fertilize both land and water, and it also blocks or reflects sunlight, and affects the formation of clouds. The dust consists mainly of aerosols measuring between 0.1 and 20 microns across–less than 1/1000th of an inch–which remain wind-borne until they are deposited by their weight or by rainfall.
In 2014, an intense Saharan dust storm caused "very high" pollution levels in England and Wales, and prompted public health officials to issue a warning to people with respiratory problems.
Saharan dust moves over the Atlantic in 2014, in an image captured from the International Space Station.
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