Will deserts grow in a warming world?
DB: This is Earth and Sky. A listener asks, as global climate warms, is more of Earth’s surface turning into desert?
JB: A recent report by the U.N. projected an increase in the coming years of desertification, the process by which useful land becomes desert. In addition to climate change, the report cited unsustainable land use practices as a major reason.
DB: But that doesn’t mean major deserts are expanding around their edges. We spoke to Christopher Potter of the Ecosystem Modeling Group at Ames Research Center in California. He said satellite data over the past 25 years show that the southern margins of the Sahara Desert looking greener now than two decades ago.
JB: And Potter said that a warmer climate doesn’t necessarily mean a drier climate. In fact, he said, a warmer climate might bring more rainfall to many areas.
Christopher Potter: So surprisingly we may see…that we accelerate the water cycle but we don’t turn it off. . . But there are going to be winners and losers. It just, you know, it depends on where you live . . .
DB: Using climate models to predict exactly which places on Earth will get more rain – and which less – is extremely difficult.
Christopher Potter: The smaller the place you’re trying to look at, the more difficult it is to take the climate model information … and then scale it down to say, “you’re going to be OK, and you’re not.”
_JB: And that’s our show. Special thanks today to NASA explore, discover, understand. I’m Joel Block with Deborah Byrd for Earth and Sky.
Read the June, 2005 United Nations report on desertification. (PDF)
Don’t have the time to read the full report? Then skip ahead to a press release about the United Nation’s report on desertification.
Our thanks to:
Christopher Potter
Ecosystem Science and Technology Branch
NASA Ames Research Center
Moffett Field, CA
Additional Teacher Resources
NASA: Temporary Drought or Permanent Desert?
Desertification. The word invokes images of sand dunes blowing over abandoned farms as some irresistible, dark force steadily transforms fertile fields into inhospitable wasteland. The United Nations’ official definition says desertification is land degradation in typically dry areas resulting from various factors, including climatic variations and human activities.
NASA Earth Observatory: From the Dust Bowl to the Sahel
A severe drought combined with poor soil conservation practices can lead to extreme topsoil erosion, with devastating effects on the land. This is just what happened in the Great Plains region of the U.S. during the 1930s Dust Bowl years.
