Scanning Climate Change Impacts on Water Resources of the Largest African River Basins

Abstract

The objectives were to ensemble and analyze the projected signals of climate change recently published in peer reviewed outlets with respect to five African river basins, viz. Nile, Senegal & Volta, Niger, Congo, and Zambezi & Limpopo. Results of 55 papers were assessed (distributed as 30, 25, 16, 13, an d 16%, respectively). Findings stated the dominant tendency for using unmitigated emission pathways (A2 for the Nile and RCP8.5 for the remaining basins), with fewer applications to hypothetical scenarios. Compared to the individual member, the majority of the papers followed the ensemble GCMs approach to obtain robust results compared mostly (40-50%) to the 1960-1990 baseline. Nevertheless, all models agreed in the increasing trend of temperature compared to the dominant uncertain trends in rainfall. The studies applied 19 hydrological models (especially SWAT, HBV and CLiRuN) coupled with limited land use considerations. In contrast to uncertain trends in future rivers’ flow, all basins showed decreasing trends in runoff. This discrepancy in climate change projections delayed the adoption of adaptation plans. Technically, runoff, stream flows and evapotranspiration terms were largely misused. The north-south cooperation is direly needed in building observational datasets, a priori input for characterizing the regional uncertainty and better climate change projections.