The smokestacks of North American and European factories may have spawned the devastating droughts that killed millions of people in Ethiopia and other parts of the Sahel region of Africa.
Scientists have been puzzled about the source of the 40-year dry spell, among the most severe in recorded history. Now a global climate model developed by Leon Rotstayn of CSIRO Australia and Ulrike Lohmann of Dalhousie University in Canada appears to link the two phenomena.