Assessing Floods and Droughts direct impacts in sub-Saharan Africa by using a regional hydrologic model: a fully probabilistic approach

Over the last few decades, disasters resulting from natural hazards have often derailed hard-earned development progress. This is especially true in developing countries such as in sub-Saharan Africa which was the object of this study. The majority of disasters in Africa are hydro-meteorological in origin, with droughts affecting the largest number of people and floods occurring frequently along major river systems and in many urban areas. Disasters, however, can be significantly minimised with rigorous understanding of the risk, obtained using scientific risk modelling and through effective institutional and community prevention, mitigation and preparedness. Specifically, this study focuses on the risk assessment due to both Floods and Droughts in 16 countries in Sub-Saharan Africa. The study describes the crucial role of a physically based regional hydrologic model as a common engine to assess drought and flood hazard and their subsequent risk implications on people and economy. The hydrologic simulations are at the basis of the fully probabilistic approach adopted in the study. The study develops risk estimates in both current and future climate conditions, using RCP8.5 projections, paired with socio economic development (i.e., considering population and GDP growth). Results are discussed in terms of impacts on population and different key sectors of the African economy, such as agriculture and infrastructure, while especially focusing on the direct economic losses caused by flood and drought disasters and on the  food security implications of drought disasters.