Some West African countries have unconsciously neglected their northern areas that are predominantly semi-arid and poorer than the general indigenous populations. The lack of access to water for drinking and irrigation is a common concern. According to a World Commission on Environment and Development statistics, more than one-third of Africa is at present under the threat of desertification.  These changes coupled with periodic droughts, livestock over-grazing are but a part of the problem.  It is the mismanagement of the land itself that is causing desertification online source:

http://www.fao.org/docrep/Z5700E/z5700e03.htm  or Click to View Topic on Land Degradation & Mismanagement