Ambulances are queuing. Patients are sitting for hours in overcrowded waiting rooms. Others, who have been lucky enough to have had an initial assessment, are lying on trolleys along corridors wondering when a doctor will see them. Scores of elective procedures are cancelled. The intercom system is flowing with the names of clinicians who are needed to assist with yet another critically ill patient. Staff are overwhelmed, counting down the time until their shifts end, contemplating if they could even take another day of this.
This would be an all-too-familiar scene in many European hospitals in December or January, but it is also becoming an increasingly common scene in hospitals in the summer months, specifically during heatwaves, like the one that hit Europe in June.
In the span of three days, the UK broke three temperature records for the month of June, peaking at 37.3°C and exceeding the prior record set in 1976 at 35.6°C, a half century ago. On the mainland, temperature records for June were also shattered in France, Spain, and Switzerland.
July brought another heatwave, and more are predicted this summer. Is this the new normal for Europe, thanks to climate change?
Increasingly, heatwaves, and hotter temperatures more broadly, are associated with a higher demand for health services due to heat stress and exacerbations of chronic conditions.
The Copernicus Climate Change Service reports that between 1994 and 2024, global temperatures have risen by about 0.26°C per decade, meaning that the planet is now about 0.78°C warmer than it was 30 years ago. Europe, however, is warming at twice the rate of the rest of the planet, or about 0.53°C per decade, over the same period, which means that it is now warmer by about 1.59°C.
As the planet warms, heatwaves—periods of several consecutive days during which daily temperatures exceed a specific threshold—have become not only more frequent, but also more severe, longer lasting and covering wider geographic areas. The rapid onset of heatwaves, so called “heat spikes,” are becoming more common too, according to some meteorologists. During the June heatwave some locations in the UK experienced temperature increases of 10°C in just two days.
The resulting health-related impacts are becoming apparent. According to the 2025 Lancet Countdown Report, heat-related mortality has increased globally from 4.9 to 7.1 per 100,000 persons between 1990 and 2021, a 45 percent rise. Again, Europe is taking the brunt, where heat-related mortality has increased from 2.1 to 8.3 per 100,000 persons during the same period, a rise of nearly 300 percent. One study estimates that among the half a million heat-related deaths per year globally, between 2000 and 2019, 36 percent were in Europe, despite the continent composing only about 9 percent of the global population.
During winter, we have come to expect a higher demand for health services due to acute respiratory illnesses or injuries, such as falls or motor vehicle accidents, resulting from icy weather conditions. But increasingly, heatwaves, and hotter temperatures more broadly, are associated with a higher demand for health services due to heat stress and exacerbations of chronic conditions, like cardiovascular disease, diabetes, kidney disease, asthma, and frailty.
A recent study published by Oxford University, using more than 4 million patient records from general practices in England between 2007 and 2019, shows that very hot days (defined as >23°C) are associated with spikes in same-day health service utilization and mortality. The Climate Change Committee, in their recently released fourth independent assessment of UK climate risk, reports that by 2050 heat-related ED attendances and hospital admissions could triple, with costs potentially exceeding £4 billion. Another study from Portugal examining 12 million hospital records between 2000 and 2018 found that hospital admissions increased nearly 20 percent on heatwave days, with children being disproportionately affected.
These statistics should alarm national, regional and local bodies responsible for the funding, organization, and delivery of health services across Europe.
To remain resilient to the impacts of climate change, governments must take action. This includes not only ensuring that the system can absorb the increased demand for services but also that hospitals remain safe environments for patients.
In the UK, an estimated 90 percent of NHS hospital estates, which are largely composed of older buildings lacking centralized air-cooling systems, are at risk of overheating and vulnerable to heatwaves. This is true of many hospitals throughout Europe, even in wealthy countries like Germany. But even in countries where hospitals have centralized air-cooling, these systems cannot cope under extreme temperatures.
The recent June heatwave is evidence of the consequences. As hospital ward temperatures rose upward of 36°C in parts of England, staff struggled to keep patients hydrated and in stabilized conditions. Medical imaging devices, like MRIs, and IT systems also failed to work, slowing down the flow of patients through the system and resulting in longer waiting times and cancelled appointments and treatments.
[The effects of heatwaves] should alarm national, regional and local bodies responsible for the funding, organization, and delivery of health services across Europe.
These incidences are costly. During a heatwave in June 2022, hospitals in London experienced an IT outage (PDF) due to cooling system failures at two of their data centers, leading to treatment delays and £1.5 million in additional costs to the English NHS.
Last month, the World Health Organization (WHO) released a second edition of Heat-Health Action Plans, which is intended to serve as guidance document and an implementation framework, for responding to extreme heat as a public health threat. Within the HHAPs, the WHO emphasizes the need to build resilience into health systems.
Will European governments move at pace to protect its fragile health system infrastructure against climate change? This will likely require a substantial, long-term investment, but the cost of doing nothing is far greater.
