The pdf link to the article is OPEN ACCESS.
The law of unintended consequences, aka human nature, strikes again.
Scientists Show That Vegetation Conditions Drive The North Africa DroughtWilliam Lau, a Goddard Space Flight Center (Greenbelt, Md.) atmospheric scientist... along with UCLA atmospheric scientists Ning Zeng and David Neelin, found that the addition of vegetation to climate computer models proved to be the missing link in what was driving the drought... changing sea surface temperatures couldn't account for much of the drought at all... another factor -- soil moisture -- ...was only enough to account for a drought half as severe as what actually happened in the Sahel. Finally, the team added natural vegetation to the model and found that the natural vegetation interacts significantly with climate, and in the case of the Sahel drought, caused enhanced drying... Also, since plants transpire by losing water through their leaves, less vegetation decreases humidity. The loss of a direct moisture supply means less rainfall, which causes weaker circulation, dampening the monsoon season... Lau said that the new model including natural vegetation changes is a much better reflection of what the Sahel region actually experienced. And it suggests that without the addition of man-made landscape changes, the climate system is fully capable of generating this devastating type of drought.
ScienceDaily
November 24, 1999
Adapted from materials from NASA Goddard Space Flight Center