Climate Change increases the need for regulating the flow of the Nile River

 

 

MoFA June 25  2017 - A recent report produced earlier this year by researchers at the world famous Massachusetts Institute of Technology has detailed their conclusions that climate change may drastically increase the variability of the Nile’s annual output. Of course, the annual flow of the Nile has always been unpredictable and there have been many reports over the centuries of both floods and droughts affecting the River’s flow. Even in the Bible there were the reports of seven years of abundance followed by seven years of famine for Egypt. Now, research at the Massachusetts Institute of Technology (MIT) has demonstrated that climate change is clearly going to increase variability in Nile's annual flow drastically. If this is correct, it will become highly important to be able to predict the amount of variability, to forecast likely years of reduced flow and even more important to find ways to control that variability. This is particularly the case as the population of the Nile Basin, in Egypt, Sudan and Ethiopia, is expected to increase significantly by 2050. Indeed, estimates suggest it may double to a billion.

 

The MIT report, which is based on “a variety of global climate models and records of rainfall and flow rates over the last half-century”, projects a major increase in flow variation from year to year. It even considers an increase of 50% in the amount of flow variation is likely.  The report by Professor Elfatih Eltahir, Professor of Civil and Environmental Engineering and Dr. Mohamed Siam, was published in the journal “Nature Climate Change”. They found that as a result of climate warming there will be significant increases in the intensity and duration of the Pacific Ocean El Niño/La Niña cycles. These, as the researchers have demonstrated previously, connect strongly with the annual rainfall variations in the Ethiopian highlands and adjacent eastern Nile basins.  The last two years, of course, have demonstrated this link again very clearly. These regions are also the primary sources of the Nile's waters, accounting for some 80 percent of the river's total flow.

Professor Eltahir has previously shown the correlation between the El Niño/La Niña cycle and Ethiopian rainfall, helping with seasonal and short-term predictions of the river's flow, for planning storage and releases from the river's many dams and reservoirs. His new analysis adds another dimension, and can be expected to provide highly useful information for much longer-term strategies for placement and operation of new and existing dams, including the Grand Ethiopian Renaissance Dam.

Professor Eltahir notes that his latest study underlines the points to the importance of focusing on the potential impacts of climate change and rapid population growth as the most significant drivers of environmental change in the Nile basin. He says the real issues facing the Nile are bigger than any controversy between Ethiopia and Egypt over construction of the Great Ethiopian renaissance Dam, not least, as he points out because: “We think that climate change is pointing to the need for more storage capacity in the future." There can be no doubt that the Great Ethiopian Renaissance Dam would be extremely important and valuable in this connection. 

Using various different global circulation models, and assuming that major reductions in greenhouse gas emissions do not take place, the report says that if the world continues on a "business as usual" trajectory, with no major reductions in greenhouse gas emissions over coming years, the expected changing rainfall patterns will lead to an average increase of between 10 and 15% in the Nile’s annual flow. This could be a bonus for water-scarce countries but unless the water levels are properly managed, with storage and releases from the various dams and reservoirs along the Nile coordinated, there will certainly be extensive flooding in many areas.

Such an increase would mean a rise from the present average flow of 80 cubic kilometers a year to some 92 cubic kilometers averaged over the century. The findings also suggest that this means there would be substantially fewer normal years, with flows varying widely between 70 and 100 cubic kilometers per year. There will also be many more extreme years with flows greater than 100, and more years of drought. This pattern is already becoming visible over the last two years. 2015 was an intense El Niño year and saw drought conditions in the Nile basin, while the La Niña year in 2016 saw high levels of flooding. Professor Eltahir emphasized that this was no longer an abstract issue: “This is happening now."

Professor Eltahir also underlines that the knowledge of such changes can help planners be prepared not least by storing water in huge reservoirs that can be released when needed and so regulate the flow of the whole basin. Professor Eltahir’s work is already being used operationally in the region to help issue seasonal flood forecasts, providing an improved lead-time, offering water resource engineers more time to react. His work, in fact, is already playing a major role in reducing uncertainty. This latest report will only improve the prospects of effective planning and regulating flows to remove the extremes.

The experts at the Massachusetts Institute of Technology are clear: global warming means the river’s water levels will become ever more unpredictable, resulting in what could be devastating floods one year and severe drought the next. With growing variability in water levels already taking place, the last two years, the conclusions are very clear. There will be substantially fewer “normal" years when the Nile flows conform to traditional patterns. There will be greater extremes and more years of drought. Professor Eltahir and his fellow researchers hope their findings will lead to long-term policies for managing the river. The report says that instead of arguing about GERD, the focus should be on the potential impact of climate change and population growth along the Nile. “We think that climate change is pointing to the need for more storage capacity in the future,” says Professor Eltahir. “The real issues facing the Nile are bigger than that one controversy surrounding that dam.”