Ethiopia: Water resources

Ethiopia is known as the “water tower of Africa”, having twelve river basins, 22 major lakes and a groundwater potential of about 2.6 billion m3 [19]. However, rapid population growth and future variability of water resources can affect the economy through a growing energy and water demand in different sectors including agriculture, infrastructure, ecosystems and health. Precipitation strongly depends on elevation: It currently ranges from 1900 mm per year in the highlands to around 100 mm per year in low-lying areas [15]. Agricultural production follows these precipitation patterns. However, areas with high agricultural production also coincide with high population density and pressure on land, especially in the weyna dega (warm to cool climate) and dega (cool climate) zones that are best suited for the production of major staple crops in Ethiopia [20].

Per capita water availability

Figure 8: Projections of water availability from precipitation per capita and year with (A) national population held constant at year 2000 level and (B) changing population in line with SSP2 projections for different GHG emissions scenarios, relative to the year 2000.

Current projections for water availability in Ethiopia display high uncertainty under both GHG emissions scenarios. Assuming a constant population level, multi-model median projections suggest no change in per capita water availability over Ethiopia by the end of the century under RCP2.6 and only a slight increase under RCP6.0 (Figure 8A). Yet, when accounting for population growth according to SSP2 projections⁶, per capita water availability for Ethiopia is projected to decline by 65 % by 2080 relative to the year 2000 under both scenarios (Figure 8B). While this decline is driven primarily by population growth, rather than climate change, it highlights the urgency to invest in water saving measures and technologies for future water consumption.

Spatial distribution of water availability

Figure 9: Water availability from precipitation (runoff) projections for Ethiopia for different GHG emissions scenarios.

Projections of future water availability from precipitation vary depending on the region and scenario (Figure 9). Under RCP2.6, water availability will decrease by up to 30 % in southern Ethiopia and increase by up to 35 % in eastern Ethiopia by 2080. All models agree on this trend, making water saving measures in these regions particularly important after 2050. However, the picture is different for RCP6.0, where projections for the south and east of Ethiopia are less certain and the projected difference in water availability is smaller, which is why a clear trend cannot be identified.

6 Shared Socio-economic Pathways (SSPs) outline a narrative of potential global futures, including estimates of broad characteristics such as country-level population, GDP or rate of urbanisation. Five different SSPs outline future realities according to a combination of high and low future socio-economic challenges for mitigation and adaptation. SSP2 represents the “middle of the road”-pathway.

References

[19] D. Mulugeta, D. Weijun, and J. H. Zhao, “Hydropower for sustainable water and energy development in Ethiopia,” Sustain. Water Resour. Manag., vol. 1, no. 4, pp. 305–314, 2015.
[20] J. Chamberlin and E. Schmidt, “2 Ethiopian Agriculture: A Dynamic Geographic Perspective,” in Food and Agriculture in Ethiopia, 2014.