The Nile has given life to northern and eastern Africa since time immemorial. When early humans first ventured out of Africa into the Middle East and beyond, they followed the path of the Nile. In recent millennia, mighty civilisations have sprung up along its banks, making the Nile a symbol of national pride for the countries that have inherited the lands around it since. Since 2015, two of those countries have had a dispute over control of the river. Ethiopia is building a large-scale dam to harness the force of the Nile’s flow for electricity production, whereas Egypt – which lies downstream – fears that such a project will deprive much of its population of its primary water source. The Grand Renaissance Dam, as Ethiopia’s structure is known, is being built on the country’s border with Sudan. The US has endeavoured to mediate, proposing a framework in which Ethiopia would regulate the dam’s operations on a schedule mutually agreeable to Egypt and Sudan, but hopes for a solution were dashed on Saturday when Ethiopia refused to endorse the American plan. In response, Cairo has warned Addis Ababa that it would use “all means necessary” to protect the interests of Egyptians. Egypt and Ethiopia have begun a war of words that has a dangerous potential for escalation. It comes at a time when they should, instead, seize a rare window of opportunity to resolve this crisis once and for all when all parties can still count on the attention and interest of Washington. Ethiopia’s energy ambitions are valid – the country has one of the most promising economies on the African continent, and its recent political reforms are cause for celebration across the region. Furthermore, Ethiopia’s dam project – costing about $4 billion – has, like the river upon which it is being built, become a source of pride for Ethiopians. With it, their country can become Africa’s largest power exporter. But the dam may jeopardise the well-being of ordinary Egyptians, who rely on the Nile for water and agriculture. The river meets 90 per cent of Egypt’s water needs, and 80 per cent of the water drawn from it is used in farming. In Sudan, too, the Nile forms part of the backbone of the economy. The Sudanese are recovering from a host of civil and regional conflicts, along with recent political turmoil and have also been responding to the region’s locust outbreak and its threat to food security. The risk of water scarcity should not be added to the country’s challenges. At a time when many Egyptians and Sudanese are struggling because of poverty and climate change, Addis Ababa would do well to remember that the pursuit of ambition without regard for the health and prosperity of one’s neighbours is an unsustainable long-term strategy. Egypt has reached out to Ethiopia repeatedly in an attempt to find a middle ground in which the food security and energy needs of the whole of north-eastern Africa are respected. It has long been understood that access to resources – including water and electricity – will always be a regional issue in Africa, not a national one. The continent’s people and geography are too interconnected for any other approach. Now, the task for leaders in Addis Ababa, Cairo and Khartoum alike is to diminish the flow of harsh words between their capitals and to pick up the conversation again – this time on the basis that peace and prosperity lie downstream from understanding.