ECOLOGY:
The Sahara Is Not Marching Southward
Richard A. Kerr
Twenty-five years ago, images from sub-Saharan Africa led people to believe that human activity was irreversibly expanding the world's deserts, which provoked an outpouring of aid and an international treaty. For the past decade, however, scientists have been fighting the idea that such "desertification" is widespread or largely human induced. Now, they have satellite images to bolster their argument that much of what has been called desertification was instead the reflection of natural ups and downs of rainfall. That finding also opens the door for humans to help in remediating the damage.