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Sunday, August 2, 2009

Sahara desert becoming green due to climate change

According to a report in National Geographic News, if sustained, these rains could revitalize drought-ravaged regions, reclaiming them for farming communities.

This desert-shrinking trend is supported by climate models, which predict a return to conditions that turned the Sahara into a lush savanna some 12,000 years ago.

The green shoots of recovery are showing up on satellite images of regions including the Sahel, a semi-desert zone bordering the Sahara to the south that stretches some 2,400 miles (3,860 kilometers).

Images taken between 1982 and 2002 revealed extensive regreening throughout the Sahel, according to a new study in the journal Biogeosciences.

The study suggests huge increases in vegetation in areas including central Chad and western Sudan. he transition may be occurring because hotter air has more capacity to hold moisture, which in turn creates more rain, according to Martin Claussen of the Max Planck Institute for Meteorology in Hamburg, Germany.

"The water-holding capacity of the air is the main driving force," Claussen said.

While satellite images can't distinguish temporary plants like grasses that come and go with the rains, ground surveys suggest recent vegetation change is firmly rooted.

Throughout North Africa, new trees, such as acacias, are flourishing, according to Stefan Kropelin, a climate scientist at the University of Cologne's Africa Research Unit in Germany.

"Shrubs are coming up and growing into big shrubs. This is completely different from having a bit more tiny grass," he said.

SOURCE : National Geographic

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