Beirut: As the summer sun scorches Europe, the effects of a warming planet are becoming increasingly tangible - and while nuclear energy is often touted as part of the solution, it too is buckling under the heat.

According to Anadolu Agency, Paul Dorfman, chair of the Nuclear Consulting Group and a senior academic at the University of Sussex, has highlighted the vulnerability of nuclear power in the face of climate change, stating that it could become a significant and early casualty.

This year, several European plants have reduced output or shut down altogether - not due to technical faults, but because the rivers that cool them are either too shallow or too hot. France, where nuclear accounts for around 65% of electricity, has been particularly affected, with nearly all of its 18 nuclear sites reporting capacity reductions this summer.

Europe hosts around 166 operable nuclear reactors with a combined capacity of nearly 149 gigawatts (GW), approximately one-third of the global total. France leads with 57 reactors, followed by the UK with nine. Other major operators include Spain, Sweden, Finland, Switzerland, and Belgium, with smaller but strategic fleets in the Czech Republic, Hungary, and Slovakia. Most of these reactors were designed decades ago without climate resilience in mind and rely heavily on water - often drawn from nearby rivers - to cool the systems that produce electricity.

Dorfman explained that when river levels drop or water temperatures rise too high, the cooling process becomes less effective, and in some cases, dangerous. 'If that . superheated water is discharged back to the rivers, basically it kills the river ecology,' he said, noting that France has breached regulatory temperature thresholds. Inland reactors are already suffering due to 'low flow and heating' in rivers such as the Rhone and the Loire, two of the country's most crucial cooling sources.

While France may be the worst hit, the same situation played out in several countries this summer. In Switzerland, at the Beznau plant on the Aare River, one reactor was halted entirely and the other reduced to 50% capacity. Other inland reactors across Central Europe, including those in countries like the Czech Republic, Hungary, and Slovakia, face similar vulnerabilities.

The issue is compounded by projections that Europe's extreme heat events will only intensify in the coming decades. According to the European Environment Agency, Europe is the fastest-warming continent in the world, with temperatures rising at roughly twice the global average rate. Recently, the UK Met Office said that scorching temperatures are becoming the new normal, along with more frequent extreme events like drought, flash flooding, and storms.

Europe's energy dilemma is further complicated by surging electricity demand during heat waves, driven largely by air conditioning. Just as power is needed most, nuclear output often declines. According to a new report by energy think tank Ember, the June-July 2025 heat wave caused electricity demand to surge by 14% in Spain, 9% in France, and 6% in Germany.

There are signs of a shift towards renewables, however. According to Ember, solar power accounted for 22% of the EU's electricity generation in July, narrowly surpassing output from the bloc's nuclear power plants. Combined generation from natural gas and coal fell short of both solar and nuclear. Meanwhile, electricity produced from wind and hydropower sources exceeded that of all fossil fuels combined.

Dorfman and Czyzak emphasize the growing importance of renewables and energy efficiency measures in building a more resilient power system. Although the transition will take time, the increasing deployment of solar power and other renewable sources offers a promising path forward.