Europe's worst drought in decades is rippling through the continent's transport, energy and agricultural sectors, bringing shipping on parts of the Danube to a standstill, threatening nuclear power generation and exposing growing vulnerabilities as climate change pushes temperatures to unprecedented levels.

The immediate crisis is centred on the Danube, where record-low water levels have forced partial closures of nuclear power plants in Hungary and Romania, while severely disrupting one of Europe's most important inland shipping routes, with knock-on effects stretching from Germany to the Black Sea.

Paks shutdown looms

Hungary has activated a three-tier contingency plan to maintain electricity supplies after warning that the Paks nuclear power plant could be forced to close completely within days because there is insufficient water in the Danube to cool its reactors. Paks, which has four reactors with a combined capacity of around 2 GW, normally supplies almost half of Hungary's electricity consumption during peak summer periods.

The Paks nuclear power plant could be completely shut down for the first time in its 42-year history within the next two to three days, Prime Minister Peter Magyar said after hosting Bavarian Minister-President Markus Söder in Budapest. State utility MVM later confirmed the announcement, saying the shutdown, which does not constitute a nuclear safety emergency, would be carried out gradually and in accordance with nuclear safety protocols. The cooling of the plant while offline is guaranteed, it added.

The crisis has been driven by exceptionally low water levels on the Danube. At Paks, the river had fallen to a historic low, around 24 cm below the previous record set in 2018, creating an unprecedented operational challenge for both the nuclear station and Hungary's electricity system. Water levels are expected to decline further as another heatwave develops over the region, making a restart unlikely in the short term.

The situation has been compounded by an unrelated technical failure at the Dunamenti Power Plant, removing a further 400 MW of generating capacity from the grid. Magyar said electricity demand during the current heatwave was expected to reach around 7,200 MW during the evening peak, roughly 20% above a normal summer evening, although still below the all-time summer record.

To maintain supplies, the government has activated a three-stage emergency plan that includes maximising domestic generation and increasing electricity imports; reducing industrial demand and cutting electricity consumption in government buildings. Magyar also appealed directly to households to delay energy-intensive activities such as electric vehicle charging and air conditioning until after the evening peak. He pointed out that Hungary also has an existing rotational load-shedding plan that could be activated if all other measures fail.

"Given the gravity of this unprecedented situation, we ask both major consumers and the public to act responsibly. It is in all our interests to avoid unplanned outages and an unexpected but previously experienced system collapse in Western Europe."

Magyar also criticised previous governments for failing to prepare for a risk that experts have highlighted for years. He said construction of a new pumping station costing HUF10bn (€28mn) would have enabled the nuclear plant to continue drawing cooling water from the Danube even under exceptionally low river conditions, potentially delaying the shutdown by days or weeks and avoiding billions of forints in electricity import costs. Instead, he alleged, MVM had spent "hundreds of billions of forints" on politically motivated advertising, sponsorships and sports clubs, adding that those decisions would be investigated.

Hungary is not alone. At Romania’s Cernavoda nuclear power plant, Unit 1 was taken offline on July 28 because of the low flow of the Danube, leaving only one reactor generating electricity. Together, the two units normally provide around 20% of Romania's electricity demand during the summer. The company warned that the second reactor could still be shut down at any time if river conditions deteriorate further.

Romania's state nuclear operator Nuclearelectrica (BVB: SNN) said it managed to keep the remaining reactor operating after overnight monitoring showed stable conditions, delaying what could otherwise have become a complete shutdown.

Further upstream, Bulgaria's Kozloduy nuclear power plant has so far remained operational despite the drought. The station's location and engineering have helped shield it from the worst effects of the falling river. Its pumping station was designed with 34 high-capacity pumps capable of drawing water through deep suction channels even during exceptionally low river levels, allowing both reactors to continue operating.

The problems in the nuclear sector are not confined to Central and Eastern Europe. As well as the damage to agriculture across much of Europe, earlier this month, France temporarily shut down three nuclear reactors and reduced output at eight others because cooling water discharged back into rivers would otherwise have exceeded environmental limits during the heatwave.

Record-breaking temperatures

The prospect of simultaneous disruption to nuclear generation across several Danube countries has heightened concerns about regional electricity security just as Europe experiences another summer of record-breaking temperatures.

Scientists say this summer's extreme temperatures have broken the normal "Bell curve" distribution of temperature variations and shifted it sharply towards unprecedented highs, as reported by IntelliNews.

Researchers say temperatures are now moving beyond the range of historically observed climate variability, while a rapidly developing super El Niño has pushed global ocean temperatures to fresh records. The warmer oceans disrupt atmospheric circulation patterns by causing hot air to rise, altering wind systems around the world and contributing to floods in some regions, violent storms elsewhere and prolonged drought across large parts of Europe.

For governments across the continent, the immediate priority is maintaining electricity supplies, keeping freight moving and protecting harvests. But the scale and breadth of the current crisis are also fuelling a broader debate over whether infrastructure built around historical climate patterns is equipped to cope with a future in which record-breaking heat, prolonged drought and extreme weather events become increasingly frequent rather than exceptional.

Danube shipping disrupting

In Central and Southeast Europe, the consequences have already extended well beyond the electricity sector. The Danube, Europe's second-longest river and one of its most important inland transport corridors, has become increasingly difficult to navigate as water levels continue to fall to historic lows across much of Central and Southeast Europe.

The Danube is a crucial export route for agricultural commodities from Central Europe, linking Germany, Austria, Slovakia and Hungary with Romania's Black Sea port of Constanța.

In Budapest, the river fell to just 26 cm on July 28, breaking the previous record low of 33 cm set in 2018, while river flow has dropped to around 60% below its long-term average.

The Hungarian authorities say the combination of prolonged heat across both the Alps and the Carpathian Basin and the absence of significant rainfall across the Danube and Tisza catchments means water levels are likely to continue falling over the coming days, with little immediate relief in sight as another heatwave approaches.

Much of Hungary's wheat, maize and oilseed harvest is transported by barge downriver before being loaded onto ocean-going vessels for export to international markets. However, with river depths falling below navigable levels in several sections, barges are operating at only a fraction of their normal capacity. Industry estimates suggest grain vessels are carrying 20-40% less cargo than usual, while some barges have been forced to reduce loads to just 10-20% of capacity, sharply increasing transport costs because more voyages are needed to move the same volume of freight.

Although exporters can switch cargoes to rail or road, both alternatives are significantly more expensive and risk undermining the competitiveness of Central European grain on world markets.

In Serbia, water levels near Bezdan have fallen to minus 131 cm, prompting the provincial government to declare a state of emergency in Sombor and the municipalities of Kula and Vrbas. Officials warned earlier this month that critically low water levels could halt navigation on parts of the Danube altogether.

The Danube at Bratislava measured only 217-218 cm on July 27, a 30-year low. Authorities have introduced water-saving measures at the Gabčíkovo dam complex and warned that river transport could be suspended altogether if levels continue to fall.

Boat operators have already been instructed to assess whether vessels can navigate safely based on their draft.

"Boat captains have to assess whether they are still able to cross considering their weight and draft. If not, they are required to dock somewhere and wait for the situation to improve," Peter Molda, chief executive of state water company Vodohospodárska výstavba, told Slovak broadcaster STVR.

Fuel supplies disrupted

The river's problems are affecting fuel supplies. Barges carrying petroleum products from Austrian, Slovak and downstream Danube refineries have been delayed, raising concerns over shortages for smaller fuel distributors if low water levels persist.

Serbia’s Energy Minister Dubravka Đedović Handanović said barges were carrying only 30-40% of their normal cargoes, with only around one quarter of planned July petroleum imports reaching the country.

Alternative deliveries by road and rail have increased costs but cannot fully replace river transport, officials said.

The Serbian government has sought to offset the disruption by relying more heavily on domestic refining at the Pančevo refinery while maintaining strategic diesel reserves.

Moldova has declared a 30-day state of alert in its energy sector after commercial diesel inventories fell to the equivalent of just under seven days of consumption. The government said low Danube water levels had reduced the carrying capacity of fuel barges by around half and restricted access by larger vessels to the country's Giurgiulești river port, forcing importers to rely more heavily on costlier road transport. The shortages have coincided with peak agricultural demand during the harvest and winter sowing season.

"It is important to act proactively to prevent a diesel shortage, particularly during the agricultural season, and ensure that the country continues to receive fuel," Prime Minister Vasile Tofan said.

Ukraine routes squeezed

The disruption comes at an especially sensitive time for regional trade. Ukraine has increasingly relied on Danube shipping routes since Russia's attacks on Black Sea port infrastructure reduced the country's maritime export capacity. At the same time, restrictions at Russia's Black Sea port of Novorossiysk and continuing security risks across the region have diverted additional freight towards the Danube, placing further strain on an already constrained transport corridor.

Grain traders have begun diverting some wheat shipments towards the Danube as Russian attacks intensify against Black Sea port infrastructure. However, most exporters remain reluctant to abandon the main maritime corridor through Greater Odesa because alternative routes lack sufficient capacity. Greater Odesa handled almost 97.2mn tonnes of cargo in 2024, dwarfing the Danube's estimated capacity of around 1.3mn tonnes per month. Rail and road exports to the European Union are also constrained by border crossings and railway infrastructure.

The problems are compounded as the Danube now faces mounting bottlenecks from low water levels, limited storage facilities, shortages of barges and increasing congestion at Romania's port of Constanța, reducing its ability to compensate for disruptions elsewhere.

Agriculture suffers

Across Europe, agriculture is emerging as another major casualty of one of the hottest summers on record.

A June heatwave destroyed more than €2bn worth of grain crops, with France and Hungary among the hardest-hit countries, according to economic analyst and former National Bank of Ukraine governor Kyrylo Shevchenko, IntelliNews reported.

Within weeks, EU and UK grain production forecasts were reduced by almost 9mn tonnes after extreme heat struck wheat during its critical grain-filling stage across central and southern France, southern Germany, Austria, Poland and Hungary. Spring barley suffered even greater damage than winter varieties. The losses threaten to add another source of inflationary pressure to European food markets at a time when global agricultural supply chains are already under strain from conflicts in Ukraine and the Middle East.

Poland is also experiencing one of its most severe droughts in decades. After an exceptionally dry start to the year, cumulative rainfall by the end of May was more than 100 millimetres below the 1991-2020 average, according to the country's meteorological service. By July 20, drought conditions were affecting spring cereals across nearly two-thirds of Poland's municipalities, while hydrological drought warnings had expanded nationwide by the end of the month.

The prolonged water deficit has also increased wildfire risks. More than 300 hectares of the Solska Forest in eastern Poland were destroyed in the country's largest fire of the season, while much of the country remains under medium to high fire-risk warnings.

The Moldovan government declared a hydrological alert after water levels in the Dniester basin fell sharply, warning that reduced flows could eventually affect public water supplies.

Tourism has also suffered. Around Budapest, sightseeing boats and hydrofoil services have been operating reduced schedules, while several international cruise operators have shortened or cancelled itineraries, transferring passengers by bus where navigation has become impossible.