Climatic perspectives on Sahelian desiccation: 1973-1998

The African Sahel provides the most dramatic example of multi-decadal clima te variability that has been quantitatively and directly measured. Annual r ainfall across this region fell by between 20 and 30 per cent between the d ecades leading up to political independence for the Sahelian nations (1930s to 1950s) and the decades since (1970s to 1990s). Climatic perspectives on the nature and causes of this period of desiccation have changed and, in s ome cases, matured as the years - and the drought - continued. This paper r eviews these changing perspectives and reflects on three central questions: How unique an occurrence has been this desiccation in the recent human his tory of the Sahel? Can we find an adequate explanation for this desiccation in the natural forces that shape the climate system, or do we have to impl icate human interventions in the system? Is our understanding of climate va riability sufficient to allow us to develop seasonal rainfall forecasting c apabilities for the region? (C) 2001 Elsevier Science Ltd. All rights reser ved.