Why Europe's cities are struggling to cope with 40-degree heatwaves

As thousands die during European heatwaves despite advanced healthcare, doctors say buildings, urban planning, ageing populations and inadequate preparedness are turning heat into a silent killer

The World Health Organization (WHO) has called heat the leading weather-related cause of death in Europe. On Sunday, the global health agency said more than 1,300 excess deaths have been recorded across Europe since June 21 as a result of the continent's record-breaking heatwave. French health officials said about 1,000 more deaths than expected had been recorded since June 24, mostly among older people.

 

Temperatures have crossed 40 degrees Celsius in several countries, schools have shut, rail services have been disrupted, and power systems have come under pressure. But why does one of the world's richest regions continue to struggle with extreme heat?

 

Europe's heat is getting hotter and lasting longer

"The increasing intensity of heatwaves in Europe is primarily being driven by anthropogenic climate change, which has increased both baseline temperatures and the frequency of extreme heat events," Dr Ranjan Modi, senior consultant, interventional cardiology, Cardiac Care, Medanta Noida, told Business Standard.

 

He said meteorological phenomena such as heat domes and persistent atmospheric blocking patterns can trap hot air over a region for prolonged periods. From a health perspective, the danger depends not only on how high temperatures rise but also on how long people remain exposed to them, especially when nights stay unusually warm, and the body cannot recover from cumulative heat stress.

 

Europe is now spending more days under dangerous heat than ever before. According to the European State of the Climate 2025 report by the Copernicus Climate Change Service (C3S) and the World Meteorological Organization (WMO), 2025 recorded nearly a month of at least 'strong heat stress' across Europe on average, while parts of southern Europe experienced up to 30 more tropical nights than the 1991-2020 average, with some localised areas recording up to 40 additional tropical nights.

 

The World Weather Attribution (WWA) group found that the latest western European heatwave was 2 degrees Celsius to 4 degrees Celsius hotter because of human-caused climate change, making such events around 100 times more likely than they were just two decades ago. In 2024, southeastern Europe experienced 66 days of 'strong heat stress' and 23 tropical nights, both the highest on record for the region.

 

According to the WMO, the latest heatwave has broken temperature records across much of Europe. Here are some of the highest temperatures recorded in the past few days:

 

France (24 June): Temperatures reached 43.8 degrees Celsius in Pulluau, while the country recorded its hottest day on record with a national average temperature of 30 degrees Celsius. Overnight temperatures also hit a record 22 degrees Celsius.

Spain (23-24 June): Spain recorded its hottest June days on record. Temperatures crossed 40 degrees Celsius in many regions, while Bilbao touched 42.7 degrees Celsius, the city's highest June temperature ever.

Germany (28 June): The town of Coschen recorded 41.7 degrees Celsius after Germany broke temperature records for three consecutive days. According to the German Weather Service (DWD), 252 weather stations registered all-time temperature records, while 46 stations exceeded 40 degrees Celsius. Eastern Saxony also recorded a record overnight minimum temperature of 29.4 degrees Celsius.

Hungary (28 June): A new June record of 40.7 degrees Celsius was recorded near Budapest.

Poland (28 June): Poland provisionally recorded an all-time national temperature record of 40.5 degrees Celsius.

Czech Republic (28 June): The country also provisionally recorded its highest-ever temperature, exceeding 40 degrees Celsius.

Austria (29 June): Vienna recorded a new June record of 40.0 degrees Celsius.

United Kingdom (25 June): Southern England recorded 37.3 degrees Celsius, its highest June temperature on record. The country also experienced its warmest June on record.

Netherlands (26 June): The country recorded a new June temperature record of 39.4 degrees Celsius, prompting its first-ever Red Alert for extreme heat across eight provinces.

Denmark (late June): Denmark recorded a new all-time temperature record of 37.0 degrees Celsius, breaking a record that had stood since 1975.

Switzerland (late June): Basel recorded 39.0 degrees Celsius, the highest June temperature ever recorded there.

Built for winter, not for heat

According to the European Environment Agency (EEA) and the International Energy Agency (IEA), unlike India, where people have long lived with extreme summer temperatures, much of Europe was built for a colder climate. Homes, hospitals, schools, and transport systems were designed to keep heat in, not let it out. Air conditioning is still uncommon in many countries, while an ageing population, densely built cities and climate change have combined to make heatwaves far more dangerous than they were a few decades ago.

 

"The urban heat island effect causes densely built areas to retain heat and remain several degrees warmer than surrounding regions, especially after sunset," Modi said. Elevated night-time temperatures reduce physiological recovery and increase cardiovascular and metabolic stress.

 

Dr Santosh Kumar Agrawal, director, internal medicine, Yatharth Super Speciality Hospital, Faridabad, told Business Standard that dense concrete structures, limited green spaces, older buildings that retain heat, and low air-conditioning use make European cities particularly vulnerable. These factors keep temperatures high both during the day and night, extending exposure and limiting the body's ability to cool itself.

 

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When heat becomes deadly

Doctors say heatstroke accounts for only a small share of heat-related deaths. Instead, extreme heat acts as a trigger that worsens existing illnesses.

 

Modi said older adults are especially vulnerable because ageing reduces the body's ability to regulate temperature, and many already live with chronic conditions. Heat increases dehydration, thickens the blood and places extra stress on the heart, kidneys and lungs, raising the risk of heart attacks, strokes, respiratory failure and acute kidney injury.

 

Agrawal said people over 65 years, young children, pregnant women, outdoor workers, and patients with heart disease, diabetes, kidney disease or lung disease face the greatest risks. Many medications, including diuretics and some heart medicines, can also reduce the body's ability to cope with heat.

 

According to them, many deaths occur before patients even reach a hospital.

 

"Heatwaves are primarily a public health challenge rather than a hospital care issue," Modi said. Many victims are elderly people living alone who may not recognise symptoms early or lack access to cooling.

'Hospitals alone cannot solve the problem'

Europe introduced heat-health warning systems after the devastating 2003 heatwave that killed an estimated 70,000 people. Yet experts say preparedness still falls short.

 

Hospitals, nursing homes, and long-term care facilities often lack adequate cooling systems. Public health agencies also struggle to identify and monitor vulnerable people before temperatures peak.

 

Agrawal said prolonged heatwaves place enormous pressure on emergency services because entire populations are affected simultaneously. He added that delayed public warnings, limited outreach to at-risk communities, and weak coordination between health, emergency, and social care services continue to hamper the response.

Europe steps up emergency response

Governments across Europe have activated emergency measures as the heatwave has strained hospitals, transport systems and power infrastructure.

 

According to local media reports, France placed 58 departments under the highest Red Alert, closed hundreds of schools, issued wildfire warnings and activated emergency heat-health plans. Cooling centres were opened in many cities and authorities urged people, particularly the elderly, to remain indoors during peak afternoon hours.

 

Spain issued widespread heat alerts, strengthened public health advisories and expanded access to climate shelters and cooling spaces. Several regions also restricted outdoor work during the hottest part of the day.

 

Germany imposed speed restrictions on rail services after extreme heat affected tracks, while health authorities issued nationwide heat advisories.

 

Hungary opened more than 2,000 cooling centres across the country and maintained nationwide heat alerts.

 

United Kingdom issued Red Warnings for Extreme Heat for three consecutive days for the first time under its current warning system. Hundreds of schools closed or shortened classes, the NHS activated heat-health alerts and rail operators imposed speed restrictions.

 

Netherlands issued its first-ever Red Alert for extreme heat across eight provinces, advising residents to stay indoors, remain hydrated and avoid unnecessary travel.

 

Austria, Poland, Czechia and Switzerland issued heat warnings, advised residents to avoid outdoor activity during the hottest hours, and urged them to check on elderly neighbours and other vulnerable groups.