Though climatologists fear global warming could lead to severe African droughts that could destabilize countries there, new research reported Friday indicates that droughts even more severe than those predicted are a relatively common occurrence on the continent.
Extreme droughts lasting at least a decade have occurred every 35 to 60 years on the continent for the last 3,000 years, researchers reported in the journal Science. But interspersed with those are droughts that lasted centuries, they found.
The last such megadrought began in 1400 and lasted until about 1750, according to scientists from the University of Texas and the University of Arizona. The infamous Sahel drought that lasted from the early 1960s into the 1970s, killing 100,000 people and displacing hundreds of thousands more, pales in comparison, they said.
The findings bode ill for what could happen if the effects of global warming are added onto the natural cycles, said geoscientist Jonathan Overpeck of the University of Arizona, a co-author. “This could be devastating,” he said at a news conference.
The authors reached their conclusions by studying the 3,000-year climate record contained in sediment layers on the bottom of Lake Bosumtwi in Ghana, about 20 miles southeast of the country’s second-largest city, Kumasi.
The researchers concluded that the droughts are linked to a 60- to 80-year cycle of temperature changes in the North Atlantic called the Atlantic Multidecadal Oscillation.
