Streamflow response to climate change in the Greater Horn of Africa

The Greater Horn of Africa region increasingly experiences high risk of water scarcity. A combination of frequent droughts, rapid population growth and rising urbanization have reduced streamflow and intensified water abstraction, causing water and food shortages. Estimates of future streamflow changes in the region have so far been highly uncertain and evaluations using ground-based measurements are still limited. Here future streamflow changes are estimated using a distributed hydrological model forced with an ensemble of high-resolution climate simulations produced using the European community Earth-System Model v3.1. The simulated streamflow is evaluated using observed data from 29 stations from river basins across different climate zones in the region. Evaluation results show large sub-regional variations in the performance of simulated streamflow with monthly correlation ranging from >0.9 in the Blue Nile to <0.4 in Ruvuma basin, Tanzania. The sign and magnitude of future streamflow changes also vary between the ensembles and across river basins with varying flow seasonality. Overall, the streamflow projections indicate large (seasonal, long-term mean, and extreme) streamflow decreases for all major rivers in Ethiopia and increases in the equatorial parts of the region at the end of the century. The ensemble mean shows a 10% to 25% decrease in the long-term mean flow in Ethiopia and a 10% increase in the equatorial part of the region in 2080s. Similarly, a substantial change in high flows in 2080s, with up to -50% reduction in the northern and 50% increase in the equatorial parts of the region.

HIRPA Feyera;  ALFIERI Lorenzo;  LEES Thomas;  PENG Jian;  ELLEN Dyer;  DADSON Simon J.; 

2019-11-15

SPRINGER

JRC117455

0165-0009 (online),   

https://link.springer.com/article/10.1007%2Fs10584-019-02547-x,    https://publications.jrc.ec.europa.eu/repository/handle/JRC117455,   

10.1007/s10584-019-02547-x (online),