Sahel

Sahel, region in western Africa, serving as a transition zone between the arid Sahara on the north and the wetter tropical areas to the south. A relatively sparse savanna vegetation of grasses and shrubs predominates. Rainfall averages between 102 and 203 mm (4 and 8 in) and falls mostly from June to September. Nomadic herding and limited cultivation of peanuts and millet are possible in most areas. Desertification of the Sahel has been sped up by an extended drought between the late 1960s and early 1980s, the worst in 150 years, and the stress of increasing human and livestock populations. Desertification, whereby soil loses its ability to retain moisture and allows deserts to encroach on arable land, is shrinking the size of the Sahel and causing famine in much of the region.