Science / Medicine : Satellite Finds Sahara Expanding

Environmentalists have argued that the Sahara Desert, the world’s largest, has been steadily increasing its size southward as a result of drought and land mismanagement, particularly overgrazing, increased cultivation and firewood cutting. But evidence of the extent of this process, called desertification, has been largely anecdotal.

Researchers from NASA’s Goddard Space Flight Center in Greenbelt, Md., and Texas Tech University reported last week in Science that they had used satellite imagery to confirm the desertification process and the first good evidence of its extent.

They reported that between 1980 and 1990, the southern edge of the Sahara advanced nearly 81 miles. During that period, the total area of the desert increased by nearly 16%, from 3,333,000 square miles to 3,854,000. The new study, the authors said, should provide a good base line for future studies of changes in the desert.