Desertification

sheep on drought addled pasture Sheep on a drought-affected paddock near Uranquinty, Australia. Credit: Bidgee at the Wagga Wagga Heritage Centre. February, 2009
dust storm
Bodele Depression in Chad is the site of frequent dust storms. Even though this area is a desert, dust storms are one of the ramifications of desertification. Credit: NASA Earth Observatory, 2011.

 

Desertification is the spreading of the deserts into areas that were not previously desert, is caused by several different things.

Desertification and Conservation (PDF)