At more than 6,600 kilometres long, the Nile basin extends to 11 countries, including Tanzania, Burundi, Democratic Republic of Congo, Rwanda, Uganda, South Sudan, Ethiopia and Egypt – where hundreds of heads of state gathered to attend the COP27 climate conference in Sharm el-Sheikh starting on Sunday.  

But global warming and overuse by humans is putting the world’s second-longest river under strain. In the past 50 years, the flow of the Nile has fallen from 3,000 cubic metres per second to 2,830. A lack of rainfall and increased droughts expected in East Africa means river flow could fall by 70 percent by 2100, according to UN forecasts.  

The world body has predicted a loss of 75 percent of available water per local inhabitant. Related land erosion, crop loss and lack of electricity are also likely to have a dramatic impact on the millions of people living in Africa who rely on the river for survival.  

‘Those with the least water will have even less tomorrow’ 

At the southern end of the Nile, the impact of climate change is being felt keenly in Africa’s largest lake. Located between Kenya, Uganda and Tanzania, Lake Victoria is the largest supplier of water to the Nile, with the exception of rainfall. Yet evaporation, lack of precipitation and changes in the tilt of the Earth’s axis mean the lake is now at risk of disappearing. 

One 2020 study analysed historical and geological data from the past 100,000 years and found that the entire body of water could disappear in the next 500 years. This would have a striking impact on the Nile, a river whose basin covers 10 percent of the African continent and which is an essential resource for 500 million people living in its vicinity.  

“Those who have the least water today will have even less tomorrow because competition for water will be even more fierce,” says Habib Ayeb, geologist and emeritus professor at the Paris-8-Saint-Denis University. 

In countries such as Egypt and Ethiopia, lack of access to water among people living along the Nile is already an issue due to politics rather than climate change, says Ayeb. Priority of access is currently given to large-scale agricultural businesses as opposed to local inhabitants. “There is a lot of competition for water intensified by agribusinesses that grow produce for export. Policies that aim to export water from the Nile in the form of tomatoes or cucumbers do not take into account the [local] populations that need this water,” Ayeb adds.  

Climate change threatens to worsen the situation for millions of people. “Lower water levels due to global warming will impact those who are already the most in need,” Ayeb says.

‘Invaded’ by saltwater 

At the northern end of the great river, another effect of climate change is being felt in the Nile Delta – the sediment-rich landform where the river meets the Mediterranean Sea. This area is one of the three locations in the world most vulnerable to global warming, according to the Intergovernmental Panel on Climate Change, as the weakened flow of the river struggles to push back the sea’s rising water levels.   

Every year since 1960 the Mediterranean has worn away between 35 and 75 metres of earth in the Nile Delta. If it were to rise by one metre it would submerge 34 percent of the surrounding region in northern Egypt, displacing 9 million people.  

Dwindling river reserves are worsening the problem. “The less water there is in the Nile valley, the more the Nile Delta will be invaded by water from the Mediterranean,” Ayeb says. This does not just bring the risk of ground erosion and flooding, but also changes the composition of the river. “The layer of groundwater beneath the river delta is increasingly made up of saltwater from the Mediterranean as less and less freshwater is arriving,” Ayeb adds.  

Along the northern banks of the river the water is becoming more saline. “Very little drainage water (freshwater from the river) is making it to the Mediterranean; less than 1 billion cubic metres of water, which is ridiculous compared to what there was 40 or 50 years ago,” says Ayeb. 

Already, salt from the Mediterranean has polluted hectares of land, weakening and killing plants. Farmers have reported a reduction in the quality of vegetables. 

The situation is likely to get worse ­– if temperatures continue to increase, the Mediterranean will advance 100 metres into the Nile Delta each year, according to the United Nations Environment Programme (UNEP). Over time it estimates the Mediterranean could swallow 100,000 hectares of agricultural land situated at less than 10 metres below sea level. This would be catastrophic for Egypt, where the north of the country accounts for 30 to 40 percent of national agricultural production 

To compensate, some are trying to restore the balance of freshwater in their fields using measures that are worsening the overall problem, such as pumping water from further down the Nile and constructing dams. 

The cost of hydroelectricity 

In the 10 countries that the Nile runs through, the river is not just a source of water, but also of energy. Sudan generates more than half of its electricity resources from hydropower. In Uganda, the figure rises to 80 percent.   

But this energy source is becoming increasingly unreliable. In Uganda electricity cuts are already a frequent occurrence, says Twinomuhangi Revocatus, senior lecturer at Makerere University’s college of agricultural and environmental sciences. “If rainfall goes down, water levels in Lake Victoria and the Nile will go down as well, which will reduce hydroelectric production,” he says. 

In Ethiopia, despite rapid economic growth, lack of access to electricity is a daily reality for half of the country’s 110 million inhabitants. The country’s leadership is banking on a large-scale dam to fix this, even if it means depriving neighbouring countries of electricity.

Construction on the Grand Ethiopian Renaissance Dam (GERD) began in 2011 on the Blue Nile ­– one of the river’s two major tributaries – with the aim of creating 13 turbines capable of producing 5,000 megawatts of electricity per year. Since August, 22 billion cubic metres of water have been stored in the dam’s reservoir, which has a total capacity of 74 billion cubic metres.  

This makes the structure the largest hydroelectric dam in Africa. Yet it is also a source of tension with Egypt that calls into question an agreement made in 1959 between Egypt and Sudan to share river flows, with 66 percent going to Egypt and 22 percent to Sudan. 

Egyptian leaders fear a drastic reduction in the flow of the Nile if the GERD fills too quickly. Scientists are also taking sides, with some accused of exaggerating water loss in Egypt in order to justify a potential intervention on Ethiopian soil and others accused of minimising the issue and “betraying” their country.  

In Egypt, farmers have already seen the effects of the Aswan Dam – one of the world’s largest embankment dams. As with dams in Ethiopia, Uganda and Sudan, it has reduced levels of silt – a precious natural fertiliser – in the water. 

In Sudan, such changes – along with lack of rainwater storage and recycling facilities – are posing a huge challenge for farmers and exacerbating a crisis that has left one out of four people facing severe hunger.

Like other countries along the Nile, Sudan is near the bottom of Notre Dame University’s GAIN rankings, which measure resilience to climate change. 

For Callist Tindimugaya, of Uganda’s ministry of water and the environment, rising temperatures will impact not just the country’s ability to feed its people but to generate electricity to power homes and industry. 

“Short heavy rains can cause flooding. Long dry periods will bring loss of water,” he said. “And you cannot survive without water.”

This article was translated from the original in French.