One-third of the Earth's surface is at risk, driving people into cities and destroying agriculture in vast swaths of Africa. Thirty-one percent of Spain is threatened, while China has lost 36,000 square miles to desert--an area the size of Indiana--since the 1950s.
This week the United Nations marks the 10th anniversary of the Convention to Combat Desertification, a plan aimed at stopping the phenomenon. Despite the efforts, the trend seems to be picking up speed--doubling its pace since the 1970s.
"It's a creeping catastrophe," said Michel Smitall, a spokesman for the U.N. secretariat that oversees the 1994 accord. "Entire parts of the world might become uninhabitable."
Slash-and-burn agriculture, sloppy conservation, overtaxed water supplies and soaring populations are mostly to blame. But global warming is taking its toll, too.
The United Nations is holding a ceremony in Bonn, Germany, on Thursday to mark World Day to Combat Desertification, and will hold a meeting in Brazil this month to take stock of the problem.
The warning comes as a controversial movie, "The Day After Tomorrow" is whipping up interest in climate change, and as rivers and lakes dry up in the American West, giving Americans a taste of what's to come elsewhere.
The United Nations Says:
* From the mid-1990s to 2000, 1,374 square miles have turned into deserts each year -- an area about the size of Rhode Island. That's up from 840 square miles in the 1980s, and 624 square miles during the 1970s.
* By 2025, two-thirds of arable land in Africa will disappear, along with one-third of Asia's and one-fifth of South America's.
* Some 135 million people--equivalent to the populations of France and Germany combined--are at risk of being displaced.
Most at risk are dry regions on the edges of deserts--places like sub-Saharan Africa or the Gobi Desert in China, where people are already struggling to eke out a living from the land.
As populations expand, those regions have become more stressed. Trees are cut for firewood, grasslands are overgrazed, fields are over-farmed and lose their nutrients, water becomes scarcer and dirtier.