Since Ethiopia announced its plan to build the Grand Ethiopian Renaissance Dam, it has inspired threats of sabotage from Egypt, which sits downstream and relies on the Nile for electricity, farming and drinking water. Egypt claims that it is entitled to a certain proportion of the Nile’s water based on colonial-era treaties….
By 2050 around a billion people will live in the countries through which the Nile and its tributaries flow. That alone will put enormous stress on the water supply. But according to a study by Mohamed Siam and Elfatih Eltahir of MIT, potential changes to the river’s flow, resulting from climate change, may add to the strain. Messrs Siam and Eltahir conclude that on current trends the annual flow could increase, on average, by up to 15%. That may seem like a good thing, but it could also grow more variable, by 50%. In other words, there would be more (and worse) floods and droughts.
There is, of course, uncertainty in the projections, not least because differing global climate models give different numbers. But the idea that the flow of the Nile is likely to become more variable is lent credibility, the authors argue, by the fact that trends over decades seem to agree with them, and by consideration of the effects of El Niños.
More storage capacity will be needed to smooth out the Nile’s flow. But unlike Egypt’s large Aswan Dam, which was built with storage in mind, the new Ethiopian one is designed for electricity production. Once water starts gushing through its turbines, it is expected to produce over 6,000 megawatts of power. It is unclear, though, if the structure has the necessary flexibility to meet downstream demands in periods of prolonged drought.
The talks between the three countries, Ethiopia, Sudan and Egypt, seem to be glossing over the potential effects of climate change. “Nowhere in the world are two such large dams on the same river operated without close co-ordination,” says another study from MIT. But so far co-operation is in short supply. The latest round of talks has been postponed. Even the methodology of impact studies is cause for wrangling.
Excerpts from: Climate Change and the Nile: Flood and Famine, Economist, Aug. 5, 2017