For a severe heatwave that swept through much of Europe in late June 2026, about 10,000 excess deaths are estimated, a new scientific analysis has shown. And the alarming findings have reignited fears of the growing health dangers of extreme heat as climate change continues to increase the frequency, intensity and duration of heatwaves in Europe.
Researchers used mortality data and statistical models to estimate the number of excess deaths (a measure of total number of deaths during a period of time compared to what would normally be expected based on historical trends). Excess mortality does not mean that every death was caused by heat, but it is an important indicator of the overall impact of extreme weather on public health.
The late June heatwave gave rise to record-high temperatures in a number of European countries, and a lot of them experienced extreme heat for a long time. Daytime temperatures were well above seasonal levels, and nights were high as well, with little relief for the most vulnerable groups. Some areas saw temperatures above 40 degrees Celsius and healthcare systems were under great strain and heat-related illnesses were likely to occur.
Health experts say extreme heat can have deadly consequences on the human body. The risk of heat exhaustion, heatstroke, dehydration and cardiovascular complications increases as you remain exposed to high temperatures for longer. Many other diseases (heart disease, respiratory problems, kidney diseases, diabetes etc.) are also worse when extreme heat is present.
Older people are especially vulnerable, since their bodies are less efficient at controlling temperature. Infants, young children, pregnant women, outdoor workers and people with chronic health problems are also high-risk groups. Public health agencies across Europe issued repeated warnings during the heatwave; they recommended people to keep hydrated, to avoid direct sunlight during peak afternoon hours and to seek cooler environments whenever possible.
Researchers say the results are consistent with growing evidence of global warming and climate change contributing to hotter and more dangerous heat events. Rising global temperatures have made heatwaves more common and more intense in many parts of the world. Natural weather variability is still a factor on the individual side, but climate researchers have concluded that human-induced global warming has driven record-breaking temperatures to all-time highs; so far, there is no doubt that climate change is responsible for global warming and global warming is a global phenomenon.
Urban areas were hardest hit due to the urban heat island effect, which is the heat island effect in which buildings, roads and other city infrastructure absorb and retain heat (and thus are far warmer than the surrounding rural areas). The relatively small green space and dense construction also contribute to elevated temperatures, especially at night.
European governments took various emergency measures during the heatwave. They opened cooling centers, expanded emergency medical services, issued public health advisories, and asked employers to shorten working hours for outdoor laborers. Hospitals and emergency departments also planned to meet increased numbers of patients suffering from heat-related conditions.
Excess mortality estimates can provide insights into the larger impact of extreme weather on society. Besides direct illnesses from heat, high temperatures can also exacerbate pre-existing medical problems, pollution of air quality by the formation of ozone, and the burden on healthcare facilities. These indirect effects often contribute significantly to the total mortality of large heatwaves.
The latest results have made climate adaptation strategies even more crucial. Public health experts would like to see improved early warning systems, an urban planning plan that is tree-friendly, more shaded public spaces and a way of cooling vulnerable communities during extreme weather events. Resilient healthcare infrastructure is also a key factor as heatwaves become more common.
Climate experts say Europe has experienced numerous deadly heatwaves over the past two decades with some of the most deadly events in 2003, 2019, 2022 and subsequent years. Each of these events has convinced climate change experts that preparedness is critical as well as reducing greenhouse gas emissions to prevent global warming from increasing in the long term.
The World Health Organization and various environmental agencies have long warned that heat is among the deadliest natural hazards. Unlike storms or floods, heat-related deaths usually occur quietly for a few days, and the full impact will be apparent only after a mortality analysis has been conducted.
Researchers stress that although adaptation measures can significantly reduce health risks, addressing the issue of climate change's underlying cause is as important. Green energy and climate change are important long-term solutions but reducing carbon emissions, switching to cleaner sources of energy and strengthening international climate cooperation are also seen as key components of long-term solutions.
The estimated 10,000 excess deaths of Europe’s late-June heatwave are another reminder of the increasing human toll of extreme weather. Governments, health workers and the whole society are being put under more and more pressure to prepare for future climate crises and to protect vulnerable people and also strengthen their resilience to climate change.
