Outline the main controversies involved in the desertification debate.

             Despite the fact that desertification is not a new concept, having occurred for "millennia" (Grainger, 1990) or "since the Neolithic" (Spooner, 1985), it has only in the last three or four decades been thrust into the limelight. It was conceptualised as a serious problem for the first time in the 1970s, upon the recognition of the varying patterns of spatial desert conditions, especially in the Sahel, where such changes coincided with a period of sustained drought. It was perhaps the "first big environmental issue" (Thomas + Middleton, 1994) which encompassed not only environmental issues, but also wider social, political and economic angles. It is thus no surprise that its study, interpretation and extent are clouded with controversy, as the complexity of the issue does not lead to any universally accepted and agreed explanations of the phenomenon. This complexity is further hampered by our practical inability to extrapolate individual causes and effects, from what is in reality, an interactive, multi-factorial system. .

             "Desertification is fraught with confusions and contradictions, generalisations based on a lack of data, and uncertainties stated as facts" (Thomas + Middleton, 1994).

             Similarly, concern arises as to the spatial areas of vulnerability to desertification, their areal extent, and the temporal nature of the phenomena, which will set it apart from the naturally variable and stochastic nature of climate in drylands, and emphasise its irreversibility.

             Semi-arid areas are more at risk to the supposed effects of desertification, as these form the desert (arid) borders, which are where desertification was initially believed to operate. The United Nations Environmental Programme (UNEP) believes that 35 % of the world is at risk to desertification, with especial risk for the 22 countries in the Sahel region, forming the southern border of the Sahara.