Trains arrêtés, routes liquéfiées et centrales arrêtées: l'Europe n'a qu'un avant-goût de ce que peut apporter la chaleur extrême

Extreme heat waves have struck Europe with unprecedented intensity, causing widespread disruptions to transportation systems, infrastructure, and human life. As temperatures soared well above historical norms during late June 2026, the continent witnessed a series of crises that exposed the vulnerabilities of modern societies to climate change. From melting asphalt on roads and railways to the paralysis of nuclear power plants, the effects were both immediate and alarming. These events serve as a stark warning of what could become routine in the coming decades if global efforts to mitigate climate change remain insufficient.

The heat wave reached its peak in mid-June, with temperatures in parts of Europe climbing to levels previously considered impossible. In England, for instance, temperatures hit 35 degrees Celsius, nearly 12 degrees above the average for the season. Such conditions led to the cancellation of a major conference on extreme heat hosted by the London School of Economics, which had aimed to address the very issue that made the event impractical. The organizers cited inadequate cooling systems in their chosen venue, highlighting how even academic institutions are struggling to cope with the new normal.

Transportation networks across Europe faced significant challenges. In Britain, the National Rail service reported issues ranging from fallen overhead lines to track deformation and fires along the edges of railway lines. Both National Rail and LNER advised passengers against non-essential travel. Across the Channel, French rail operators acknowledged severe impacts from the heat, cancelling up to 71 intercity trains daily. Belgium and Austria reduced train speeds and suspended approximately 100 routes per day. Similarly, the high-speed Eurostar network experienced cancellations and speed reductions due to the extreme temperatures.

One of the most visually striking consequences of the heat wave was the liquefaction of asphalt on road surfaces. In Leipzig, Germany, a tram system became unusable when melted bitumen flooded the tracks, creating a thick, dark substance that blocked movement. Residents were called upon to assist in clearing the affected areas. Similar incidents occurred in Nuremberg, where tram services were halted due to the same phenomenon. In several German highways, sections of road lifted due to thermal expansion, forcing closures. In France, six kilometers of asphalt melted along the Meurthe-et-Moselle route, while in Great Britain, stretches of roads were covered with sand or rock dust to prevent further damage from softened surfaces.

Beyond the physical destruction of infrastructure, the human toll of the heat wave was profound. In London, the ambulance service received a record number of emergency calls, with over 6,400 classified as critical. In France, hospitals struggled to manage the influx of patients suffering from heat exhaustion, with some staff resorting to seeking ice from fast-food outlets to treat patients. Preliminary reports indicated more than 1,000 additional deaths attributed to the heat, though the actual figure is believed to be much higher, potentially exceeding 20,000 due to delayed reporting of fatalities among isolated elderly individuals.

The economic implications of these events are equally concerning. According to a report by ING's global head of macroeconomics, Carsten Brzeski, extreme heat is becoming a significant factor affecting economic growth, productivity, inflation, and supply chains across Europe. The analysis noted that the current heat wave bore similarities to the restrictions imposed during the pandemic, albeit with a different cause. Countries such as France, Germany, Switzerland, and the United Kingdom were particularly hard-hit, with the latter experiencing a recurrence of the devastating 2003 heat wave that claimed thousands of lives.

Economic studies suggest that the loss in productivity due to extreme heat could reduce European GDP by between 0.3% and 0.5%, with some regions losing over 1%. Additional costs include increased energy expenditure for cooling, supply chain interruptions, damage to transport infrastructure, agricultural losses, and rising healthcare expenses. Research conducted jointly by the University of Mannheim and the European Central Bank estimated that the European economy lost about 0.3% of GDP in 2025 due to extreme weather events, with potential cumulative losses reaching up to 0.8% by 2029 if such occurrences become more frequent.

The long-term risks associated with extreme heat extend beyond immediate economic impacts. Disruptions to supply chains, declining tourism revenue in affected regions, and increasing investments in climate adaptation measures are anticipated. The European Central Bank has warned that prolonged heat and drought could increase food prices by 0.4 to 0.9 percentage points, an effect that could intensify in the coming decades.

Germany, despite being traditionally less vulnerable to extreme heat compared to Southern Europe, faces significant risks due to its infrastructure and housing stock being designed for cooler climates. An analysis commissioned by the World Bank highlighted Germany's lack of a comprehensive strategy to manage extreme heat risks, noting that infrastructure adaptation lags behind the pace of climate change. Businesses in Germany and Spain increasingly cite extreme weather conditions as factors hindering production, indicating broader economic repercussions.

As the world grapples with the escalating impacts of climate change, the recent heat wave serves as a sobering reminder of the urgent need for adaptive strategies and mitigation efforts. With the frequency and severity of such events projected to rise, the challenge lies not only in responding to each crisis as it arises but in proactively building resilient systems capable of enduring the changing climate.