The Sahelian Climate

Abstract

The Sahel has experienced several drought periods in the past 500 years, however no available records show a drought as persistent and severe as the one that started in the 1960s (Nicholson 1978). Many thousands of people died and many more suffered severe disruption of their lives in the severe phases of this drought (e.g. in 1984). The human dramas and socio-economic consequences resulting from drought-induced famines in the Sahel region have presented a strong motivation for research into the causes of the drought. Ever since, the causes for this prolonged drought have been sought somewhere between two extreme views. One view considers land-surface degradation resulting from population pressure in excess of the region’s carrying capacity as the main driver. This implies the existence of positive land-surface/atmosphere feedbacks mostly internal to the region, and in principle could incite the development of mitigation strategies to reverse the trend. The other view attributes the drought to unfavourable anomalous patterns in sea-surface temperature (SST) in the oceans. This implies the existence of a driver external to the region and by nature beyond human control, and requires the development of adaptation strategies to make the region’s societies less vulnerable to droughts.