Impacts of Climate Change and Land-use Change on Water Resources in Africa

Like many continents, Africa depends on its water resources for hydroelectricity, inland fisheries, and water supply for domestic, industrial, and agricultural operations. Anthropogenic climate change (CC) has changed the state of these water resources. Land use and land cover has also undergone significant changes due to the need to provide resources to a growing population. Yet, the impact of the Land Use and Land Cover Change (LULCC) in addition to CC on the water resources of Africa is underexplored. This study investigates how precipitation, evapotranspiration (ET), and streamflow respond to CC and LULCC scenarios. We set up a SWAT+ model for Africa and calibrated it using Hydrological Mass Balance Calibration. The model was then driven by an ensemble of bias-adjusted global climate models to simulate the hydrological cycle under a range of CC and LULCC scenarios. We analyse the changes in water resources between historical and future scenarios focusing on river flows and ET. Results show that the Zambezi and the Congo River basins are likely to experience reduced river flows under CC, while the Limpopo will likely have higher river flows. The Niger River basin is likely to experience the largest decrease in river flows in all of Africa due to CC. However, the Senegal and Congo River basins have the largest difference in river flows between scenarios with and without LULCC. The projected changes have implications on agriculture and hence the livelihood of people on the continent. Our results highlight the need to adopt policies to halt global greenhouse gas emissions and to combat the current trend of deforestation in Africa given the high combined impact of CC and LULCC on water resources.