Europe's inland waterways are in crisis. The Rhine, the continent's most important commercial river, fell to a water depth of just 25 centimetres at the critical gauging station of Kaub, near Koblenz in western Germany, on Friday — matching the historic low recorded in 2018 — before recovering slightly over the weekend. A further drop to 24 centimetres, forecast for this week, would mark the lowest level since records began in 1880. The Kaub station is the benchmark for navigability on the Rhine because it determines how heavily cargo vessels can be loaded: at levels of 40 to 50 centimetres, barges can carry only around 20 to 30 percent of their normal volume. Freight rates from Rotterdam, the Netherlands' major port and the river's outlet to the North Sea, have more than tripled in two months, rising from roughly 45 euros per tonne in June to close to 150 euros in July.

The consequences are spreading rapidly through European supply chains. Shipping authorities say a complete halt to Rhine traffic remains unlikely, but cargo must be distributed across more vessels to reduce individual loads, pushing costs higher and creating bottlenecks. "There comes a time when loads are too small to be worthwhile or vessel owners are worried about damaging their ships," one commodity trader told Reuters. Record low levels have also been recorded at Cologne and at Lobith, where the Rhine crosses into the Netherlands, with river inflow running at roughly 692 cubic metres per second against a seasonal average of around 1,900.

The drought is striking simultaneously across multiple major European rivers, with severe consequences for energy production. Hungary shut down the Paks nuclear power plant — its only nuclear facility and normally responsible for around 40 percent of national generating capacity — for the first time in its 44-year history, due to insufficient cooling water in the Danube. In Romania, authorities conducted a controlled explosion on large rocks in the Danube to redirect water flow toward the Cernavodă nuclear plant, which supplies around 20 percent of Romania's electricity under normal conditions; if the measure proves insufficient, the plant faces shutdown. Serbia has cut output at coal-fired power stations due to cooling difficulties, while two car manufacturing plants run by Dacia and Ford in Romania have agreed to suspend production for more than a fortnight to reduce electricity demand. The Danube has fallen to its lowest levels in 30 years across parts of Serbia and Romania.

In Italy, the Po — the country's longest river, running through the agricultural heartland of the north — hit a historic low near the city of Cremona in late July. Authorities have raised the drought alert to "high" across the entire Po Valley. Reduced river flow has allowed saltwater from the Adriatic to push inland through the riverbed, damaging farmland that depends on Po water for irrigation.

Scientists say the crisis reflects a broader pattern driven by climate change. David Hannah, professor of hydrology at the University of Birmingham, points to rising baseline temperatures reducing river flows and to diminished snow and glacier runoff from the Alps. Dominik Schumacher of ETH Zurich says human-induced warming has already made the current drought more severe. A recent study by the World Weather Attribution group found no clear long-term decline in rainfall across much of Europe, but concluded that higher temperatures are increasing evaporation of moisture from the land, making drought conditions significantly more likely — while simultaneously raising demand for water from households, agriculture and industry.