Creeping desertification affects every fifth inhabitant in the world, and it might force some 60 million to migrate from sub-Saharan Africa to northern Africa and Europe by 2020, according to experts. The merciless transformation of arable and habitable land to desert drew the focus at a conference (Jun. 19-21) in Tunis in which some 400 scientists and policy-makers from the world's parched regions participated.