Climate change enhances interannual variability of the Nile river flow

The human population living in the Nile basin countries is projected to double by 2050, approaching one billion(1). The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation(2,3). Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% ( +/- 35%) ( multi-model ensemble mean +/- 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Nino and La Nina events(4,5) and to observed teleconnection between the El Nino-Southern Oscillation and Nile River flow(6,7). Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.