A Great (Green) Wall of Africa

http://news.bbc.co.uk/2/hi/world/africa/10344622.stm

African leaders are meeting to discuss plans for a belt of trees 15 km wide and 7,775 km long to halt the advancing Sahara desert. The belt would pass through 11 countries from east to west, covering a distance greater than the width of Canada. The trees would be "drought-adapted" species, preferably native to the area.

Organizers hope the trees will slow soil erosion, reduce wind speeds and help rain water filter into the ground, to stop the desert from growing. Richer soil content would also help communities who depend on land for grazing and agriculture.