Hydrometeorological Extreme Events in West Africa: Droughts

West African rainfall is an important part of the global climate system that influences the Atlantic thermohaline circulation, hurricane activities, and dust transport. The water cycle is linked to the monsoon and its interannual to decadal variations. Over the past decades, West Africa has seen major climate variability with extended droughts that had negative effects during the 1970s and 1980s. Indeed, when it is too scarce, rain causes shortages, reduces agricultural yields, and leads to migrations. On the other hand, when it is too abundant, it causes catastrophic floods and poses threats to populations, water resources as well as natural and farmlands. In this paper, drought is considered as part of climate-related hazards and one of the main hydrometeorological extreme events occurring in West Africa. The exposure to drought has made the region more vulnerable. Thus, two sites, namely the Niger river basin and the Bandama watershed (Côte d’Ivoire), are studied in this paper to review and analyze the weather and climate extreme events that affect vast areas of West Africa. Grounded in remote sensing, statistical, and socio-anthropological approaches, this work first reviews drought as observed from space; then assesses rainfall and evapotranspiration between 1970 and 2013 as indicators of risks of water resources scarcity in the hydro-system of the Bandama river in Côte d'Ivoire. The results reveal that the West African region is highly vulnerable to this hydrometeorological extreme event with heavy impacts on people and the economy due to a large dependency on rainfed agriculture. Thus, planning and management of drought require a change of paradigm. In addition, more comprehensive studies on hydrometeorological extreme events are necessary and policies must be better designed to significantly improve the tackling of droughts with better mitigation strategies.