Alex Byelyavtsev, a master mariner with Maersk, likes to write about the intersection of shipping, sustainability and global supply chains. Today, he discusses how extreme heat quietly dismantles Europe’s infrastructure.
In late June 2026, France recorded the hottest day in its history, a national average of 29.8°C, with one town passing 44°C and two-thirds of the country under red alert. The UK broke a fifty-year record the same week, reaching 36.1°C. Weather maps across the continent showed red alerts, and the heatwave led the news in most European countries. That is the part of a heatwave that gets reported: the temperature. It is easy to record and easy to show. The effects on shipping, power and farming are harder to see and are measured less consistently. A heatwave presses on all three at the same time, and the failures appear slowly, in figures that rarely reach the news.
Europe does not move only on motorways and railways. It moves on water. The continent has tens of thousands of kilometres of navigable rivers and canals connecting ports to factories, farms to mills, and fuel to power stations. When river levels fall, the effect is not limited to one river. It runs across a network that crosses the continent. The most important single artery is the Rhine, running from the Alps through the industrial heart of Germany to the North Sea. It is one of the busiest inland waterways in the world, carrying grains, minerals, ores, coal and oil products including heating oil, according to Reuters. The whole river is governed by one narrow point: a measuring station called Kaub, between Koblenz and Mainz, where the shallowest stretch sets the maximum load for everything moving up and down.
A drought on a river does not stop the barges. They keep sailing on schedule. But a shallow river cannot float a full hull, so each barge carries less. During the 2026 heat, traders told Reuters that vessels at Kaub could sail only about 50% full. Bloomberg reported that a barge that normally hauls up to 2,500 tonnes of diesel and jet fuel was restricted to about 1,360 tonnes past Kaub, with the gauge forecast to keep falling. In the severe drought of 2022, Bloomberg reported the water at Kaub fell to around 30 centimetres against a normal level several times that, and barges were forced to sail only a third full. In 2018, a prolonged drought dropped the Rhine to around 30 centimetres in places and forced ships to stop hauling cargo for a period, denting German industrial output. The waterway does not close, but it carries less, and the decline happens gradually rather than in a single visible event. The consequences are still large. Less cargo per barge means more barges are needed, so freight costs rise through low-water surcharges, and that cost reaches the wider economy. When Rhine shipping was disrupted in late 2018, German chemical and pharmaceutical production fell by around 10% over three months. BASF, whose largest site sits on the Rhine, said the low water that year cost it around €250 million, and economists estimated the 2022 disruption may have cut up to half a percentage point from Germany’s annual economic growth.
The Rhine is not unique. The Danube runs through ten countries from the Black Forest to the Black Sea, through a basin that covers a tenth of continental Europe, and carries much of the grain of Central and Eastern Europe. In 2022 the Danube dropped to very low levels. Across the region the drought exposed sand bars and never-before-seen islands in the shallowed channels, and barges could not load to capacity, pushing traders onto slower, costlier road and rail. The same low water reduced electricity supply: in the first half of 2022, Romania’s hydropower utility generated about a third less electricity than normal, and Serbia’s hydro output fell sharply in what researchers later called the worst hydrological year in a century. One drought reduced shipping, food transport and energy supply at the same time, through the level of a single river.
Heat also affects electricity generation. A large share of electricity depends on cold water, because nuclear and thermal plants draw river water to cool themselves and return it slightly warmer downstream. That exchange is regulated. On the Garonne in France, the river may not exceed 28°C after the plant’s water rejoins it; on the Seine, the plant may not warm the river by more than 3°C. In a heatwave the river arrives already warm, so the plant has to reduce output to stay within the limit. During the June 2026 heatwave, French nuclear output was cut by around 4 gigawatts, roughly 7% of national demand, as the Garonne, Rhône and Seine pressed against their limits. Supply fell at the same time as demand rose, because the same heat drove people to switch on cooling. In 2022, French power at one point reached around €900 per megawatt hour, more than ten times the previous year’s level. The plants were not switched off. They were throttled, and the cost moved into the price of power.
Heat also affects food production directly. The clearest example is the Po Valley in northern Italy, which produces around a third of the country’s farm output and grows roughly half of all the rice in the European Union. In 2022 the Po fell to a fraction of its normal flow, in the region’s worst drought in 70 years. With the flow so low, seawater moved upstream into the river channel, and salt reached farmland and aquifers. Rice paddies that should have stood under water dried out, and rice growers warned that up to 60% of the crop could be lost. Italy’s main farming association estimated the drought threatened around €3 billion in agriculture and put the loss as high as a third to 40% of the seasonal harvest in the worst areas. The salt left in the soil can take years to wash out.
There is one more link, and it is the one a mariner sees from the other side. When an inland barge loses half its cargo, that cargo does not disappear. It waits. Containers that should have moved up the river sit at the coast. Ocean shipping runs on schedules that assume the rivers behind the ports are working, so when the rivers shrink, the timing slips, storage fills and bookings are rearranged. A disruption that began as a few missing centimetres at an inland gauge reaches the deep-sea ports weeks later as delay. The inland leg of the journey, on a falling river, is the part that receives the least attention.
A single period of extreme heat reduced the capacity of a continent’s most important rivers, forced a nuclear fleet to cut power, damaged a harvest, and pushed the delay out to sea. Around the edges, reservoirs drained and, in 2022, nearly 900,000 hectares burned across the EU, the second-worst wildfire year on record. Most of the reporting reduced it to one line: Europe faces another heatwave. These events are becoming more frequent. The summer of 2026 brought Europe’s second major heatwave in two months, on a continent warming at twice the global rate, with infrastructure built for a cooler climate. Europe measures the heat precisely, to a tenth of a degree, everywhere, every hour. It measures far less well what the heat takes apart: the cargo that never moved, the power never generated, the harvest lost to salt. Those numbers exist, but they are rarely added together, so the most expensive part of the heatwave stays out of the account. A heatwave is not only a climate story. It is an infrastructure story.
