Droughts can grip the vast Sahel region of Africa for decades, dramatically altering the border where forest and savannahs give way to the Sahara Desert. Predicting those droughts is vital, but hard.
Trying to improve those predictions, University of Wisconsin–Madison climate scientists used data from satellites, rainfall gauges and other sources to test models of the link between rainfall and vegetation in the dry region. They found that more vegetation encourages more precipitation by drawing moisture out of the ground and recycling it into the atmosphere, where it can fall as rain again. The research can help refine climate models to improve their short- and long-term predictions for the Sahel and other regions.