A new climate study reveals what many refuse to accept about global warming: the number of deaths has been tripled during the extreme heat of June 2025.
People cool in public fountains during the heat wave of June 2025 Photo Profimedia
The heat wave caused 2,300 deaths in 12 European cities, of which 1,500 were directly attributed to the climatic crisis, warns scientists.
The pollution that warms the planet tripled the number of victims during the heat wave “Silent, but devastating” which encompassed Europe, according to a preliminary analysis carried out in 12 large cities, quoted by The Guardian.
The specialists draw an alarm signal on an increasing public health crisis, but often ignored.
Climatic changes have transformed the heat waves into silent killers
Between June 23 and July 2, the high temperatures caused 2,300 deaths in the big European cities, of which about 1,500 are attributed to the climatic collapse, the researchers say. Climatic changes have amplified heat waves, making the extremes not only more frequent, but also more lethal.
Milan was the most severely affected city, with 317 of the 499 deaths caused by heat directly attributed to human influence. Following is Paris and Barcelona, and London has registered 273 deaths, of which 171 are considered related to the pollution that warms the planet.
Two thirds of the deaths caused by the heat wave attributed to the climatic crisis
The old people are the most affected. The higher temperatures by only 2-3 ° C can make the difference between life and death.
A quick analysis by the international group World Weather Attribution, using consecrated scientific methods (but has not yet been evaluated by independent experts), shows that the climatic crisis is responsible for two thirds of the deaths caused by the heat wave that included Europe at the end of June.
According to the research, the elderly were the most vulnerable, 88% of the deaths associated with the climatic changes being registered among the over 65 years. Scientists warn that heat waves are a serious, but often underestimated danger, because victims die discreetly, in homes or hospitals, and the tragedy remains largely invisible in public and media space.
“The heat waves do not leave behind spectacular ruins as they do arson or storms. Their impact is invisible, but deeply devastating. An increase of only 2 or 3 degrees Celsius can make the difference between life and death for thousands of people ”, Explains Ben Clarke, a climatologist at Imperial College London and a study co -author.
European cities are facing record temperatures and serious consequences
The researchers used epidemiological models to estimate the number of deaths caused by heat in cities such as Paris, London, Madrid or Rome, between June 23 and July 2. Then they compared these figures with a hypothetical scenario in which the planet would not have been affected by fossil fuel pollution or the destruction of ecosystems.
However, they point out that the models were based on mortality data valid until 2019 and could not fully reflect the current ability of the population in the big European cities to adapt to the rising temperatures.
The results showed that, in some cities, the temperatures were up to 4 ° C higher due to the climatic crisis, which led to over 1,500 additional deaths. The number of victims exceeded even that of recent intensely publicized disasters, such as the floods in Spain in 2024, resulting in 224 dead, or floods in northwestern Europe, which caused 243 deaths.
Waves of heat, increasingly deadly in Europe: thousands of deaths in just 12 cities
Previous studies estimated that, on average, about 44,000 people die annually in Europe due to heat, based on data in recent decades. But the new estimate – 2,300 deaths caused by a single wave of heat, in just 12 cities – suggests that this summer could be particularly dangerous.
The European Copernicus climate monitoring service announced that June 2025 was the third hottest June in the history of global meteorological measurements. In addition, in the west of the Mediterranean, a wave of marine heat has developed “exceptional”with the average daily temperature of the sea reaching 27 ° C – the highest value ever recorded in the region for this month.
Copernicus also draws attention to the increase of tropical nights – those nights in which the temperature does not drop below 20 ° C, affecting the ability of people to rest. In some areas of Spain, up to 24 tropical nights were recorded, 18 more than the average of June.
Samantha Burgess, deputy director of the Copernicus service for climatic changes, warns that record temperatures in the Mediterranean area have greatly intensified the thermal stress felt by many parts of Europe.
“In an increasingly hot world, the heat waves will become more frequent, more intense and will affect an increasing number of people in Europe.”she said.
Mediterranean boils, on their own: Record heat waves threaten marine ecosystems
An analysis by Ocean Mercator, a non-profit organization that administers the Marine Service of the European Copernicus program, shows that almost two thirds of the Mediterranean have been hit by high or extreme intensity heat waves-the largest surface ever affected.
The high water temperatures seriously affect the marine ecosystems: it confuses the behavior of the fish and lead to the massive death of the marine plants that constitute the base of the trophic chain. In recent years, phenomena of mass mortality have become increasingly common, as these heat waves have increased in intensity.
Karina von Schukmann, an Ocean Mercator researcher, warns of a worrying phenomenon: the recurrence of marine thermal stress.
“A very alarming aspect is this constant recurrence of thermal stress. The more often, the more ecosystems become more vulnerable to these extreme phenomena“She explained.
