Our analysis shows that human-induced climate change has contributed to increasing the intensity of all 213 heatwaves analysed here. With reference to 1850–1900, the median estimates for the changes in intensity range across events from +0.3 °C to +2.9 °C. The study also reports that climate change made heatwaves about 20 times more likely over 2000–2009 and about 200 times more likely over 2010–2019.

It is an established fact that human-induced greenhouse gas emissions have led to an increased frequency and/or intensity of some weather and climate extremes since pre-industrial time, in particular for temperature extremes. Human-induced greenhouse gas forcing is the main driver of the observed changes in hot and cold extremes on the global scale (*virtually certain*) and on most continents (*very likely*). Anthropogenic forcing directly affects thermodynamic variables, including overall increases in high temperatures and atmospheric evaporative demand, which intensify heatwaves, droughts and heavy precipitation events when they occur (*high confidence*).

Heatwaves are primarily caused by high-pressure systems that trap warm air in a particular area, preventing it from dissipating. These high-pressure systems, also known as anticyclones, create a dome of heat by forcing air to sink and compress, which increases temperatures at the surface. Climate change is also a significant factor contributing to the increasing frequency and intensity of heatwaves. The rise in global temperatures due to the accumulation of greenhouse gases in the atmosphere enhances the likelihood of extreme heat events. The frequency and intensity of extreme heat events is increasing in Europe. According to the WMO Europe Regional Climate Centre (RCC), 23 of the 30 most severe heatwaves in Europe since 1950 have occurred since 2000, and five in the last three years. The frequency, intensity and duration of heatwaves are likely to continue to increase, with serious consequences for public health, as the combined effects of climate change, urbanisation and population ageing exacerbates heat-related impacts in the future.

The frequency and intensity of hot extremes, including marine heatwaves, have increased in recent decades and are projected to keep increasing regardless of the greenhouse gas emissions scenario (high confidence). Despite strong internal variability, observed trends in European mean and extreme temperatures cannot be explained without accounting for anthropogenic factors. Before the 1980s, warming by greenhouse gases was partly offset by anthropogenic aerosol emissions. Reduced aerosol influence in the recent decades has led to an observable positive trend in shortwave radiation.

World Weather Attribution studies involve several steps to determine whether, and to what extent, an extreme weather event has been influenced by climate change. Researchers analyse a wide range of climate models to compare the likelihood and intensity of the weather event in two ‘worlds’: today’s world with about 1.3ºC of warming, and a hypothetical cooler climate without warming caused by the burning of fossil fuels. They then combine observational datasets and climate models in a synthesis that "produces an overarching quantitative estimate of the change in intensity and likelihood caused by climate change," allowing attribution of how much human-caused warming changed the odds of specific heatwaves.

Extreme weather events often lead to the question: how much was this event influenced by climate change? The science of extreme weather attribution has developed over the past 15 years to try to answer this question. It can now be performed quickly after an extreme weather event occurs. The prototype activity investigated a range of extreme events. For some – such as heat waves, cold spells and large-scale precipitation events – it is deemed easier to quantify how much they are related to climate change, and therefore a ready-to-use fast attribution element of the service was set up and tested within the duration of the contract. A typical attribution analysis provides: the likelihood of that event happening in today’s climate; estimates from climate models of how much climate change affects the likelihood of the event happening; and an estimate of how the likelihood of occurrence and intensity of the event might change in the future.

Since AR5, there has been a substantial increase in detected or attributed impacts of climate change in Europe, including extreme events (high confidence). Changes in several climatic-impact drivers have already emerged in all regions of Europe: increases in mean temperature and extreme heat, and decreases in cold spells. Mean and maximum temperatures, frequencies of warm days and nights, and heatwaves have increased since 1950, while the corresponding cold indices have decreased (high confidence).

The IPCC AR6 Summary for Policymakers states: "Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and in particular, their attribution to human influence, has strengthened since AR5." Specifically for Europe, it notes that there is "high confidence" that the frequency and intensity of hot extremes, including heatwaves, have increased due to human-induced global warming. The report concludes that further increases in the magnitude and frequency of heatwaves are expected with additional warming, with Europe highlighted as a region where compound hot and dry events will become more frequent.

Researchers from several European and North American institutions assessed how human-induced climate change altered the likelihood and intensity of extreme heat in Western Europe. The analysis says that, compared with the mid-20th century, very high temperatures during the 2026 event are now expected regularly in summer, and that these heat events are tens to hundreds of times more likely than in 2003.

World Weather Attribution (WWA) states that it works "with scientists around the world" to quantify how climate change influences the intensity and likelihood of an extreme weather event. As an example, it notes that in a July 2021 study of the Pacific Northwest heatwave, "climate change made the heatwave at least 150 times more likely and 2ºC more intense," illustrating that anthropogenic warming can be a dominant factor in extreme heat events. Since its formation in 2014, WWA reports having performed more than 100 rapid attribution studies on heatwaves and other extremes, 26 of which have been additionally published in peer‑reviewed journals, indicating scientific vetting of the methods and findings.

The Copernicus Climate Change Service combines observations of the climate system with the latest science to develop authoritative, quality-assured information about the past, current and future states of the climate in Europe and worldwide. It supports society by providing information to increase resilience and improve preparedness for climate-related hazards such as heatwaves, floods and droughts. It also informs policy development to protect citizens from climate-related hazards such as high-impact weather events.

The article reports that fossil fuel emissions have rapidly worsened European heatwaves in just a few decades, citing a World Weather Attribution study. It notes that a recent analysis of temperatures in 854 cities across Europe found that nearly half have set or are expected to set new all‑time records for heat stress, and that every city surveyed in the Czech Republic, Lithuania, and Luxembourg has experienced unprecedented temperature highs. Climate researchers quoted in the piece state that "since 1980, there has been a dramatic increase in global temperatures in Europe" and caution that such extreme weather events "are likely to become more common in the future due to ongoing global warming," linking the increase in intensity and frequency of heatwaves to human‑driven climate change.

This study finds a significant upward trend in heat wave occurrences across most European regions, with a notable surge in the last three decades beginning in the early 1990s. It reports the most pronounced rise in heat wave frequency in southern regions including Spain, France, and Italy, and identifies circulation patterns that may influence the observed variability.

In Europe, there is an increasing trend in the frequency and temperature of warmer-than-average days and nights, and in the frequency and intensity of heatwaves and extreme precipitation events. In recent decades, extreme heat has been by far the leading cause of reported deaths due to extreme weather and climate events in Europe. The frequency, intensity and duration of heatwaves will continue to increase, with serious consequences for public health. The combined effects of climate change, urbanisation and population ageing is likely to significantly exacerbate heat-related impacts in the future.

Reuters reports on a World Weather Attribution analysis finding that global warming has worsened Europe's heatwaves in just a few decades. The article states that scientists concluded the current European heatwave was "virtually impossible" without human-caused climate change, and that a similar heatwave in June 1976 "would have been around 1.6 degrees Celsius cooler" in a world without today's levels of greenhouse gas emissions. The coverage emphasizes that the study attributes both increased likelihood and greater intensity of the heatwave to anthropogenic climate change rather than natural variability alone.

Researchers from the World Weather Attribution Group have published data reporting a link between the French heatwave and climate change. One expert summary states: "The results demonstrate the clear impact of human activities in making the level of extreme temperatures seen this June substantially more likely in France as a whole, and in Toulouse in particular." The same reaction notes: "Observations of present-day heatwaves show a very large increase in temperature, in fact, a similarly extreme heatwave 100 years ago would have likely been around 4°C cooler." Experts interviewed emphasise that "Heatwaves occur in any climate, but we know that heatwaves are becoming much more likely due to climate change. The global climate just keeps getting hotter, as greenhouse gases continue to build up, as scientists have predicted for decades."

Data from the Copernicus Climate Change Service show that Europe had its warmest summer on record. The period from June to August was the warmest ever on a global scale, with temperatures 0.7 degrees Celsius above the 1991–2020 average. A bulletin for May 2026 notes: "Europe experienced its seventh-warmest May and its third warmest spring, with an unusually early and intense heatwave affecting western Europe towards the end of May." It reports that daily average temperatures in parts of western France, England and Wales reached more than 10°C above average. These bulletins are based on ERA5 reanalysis data and systematically document the increasing prevalence of record-breaking heat conditions in Europe in the context of ongoing climate warming.

This World Weather Attribution page describes that after "a severe heatwave that broke all-time May records, Europe is experiencing another major heatwave that is breaking June and annual records." It explains that across France, Germany, Italy, Spain, and southern England, temperatures are reaching 5–12°C above seasonal averages, and links to the detailed study "Fossil fuel emissions have rapidly worsened European heatwaves in just a few decades," which analyzes the role of human-induced climate change. The framing indicates that the sequence of recent record-breaking European heatwaves is examined specifically to determine how much climate change has altered their probability and severity.

This attribution study concludes that the June 2019 heatwave in France "would have been almost 4°C cooler a century ago" and that such an event "has become at least five times more likely" due to human-induced climate change. The authors state: "We find that climate change increased the likelihood of the event by at least a factor of 5. In the present climate, such a heatwave is expected to occur about once every 50 years, while in a world without human-induced climate change such an event would be expected less than once every 250 years." They emphasise that the study provides a quantitative estimate of the influence of anthropogenic greenhouse gas emissions on the intensity and probability of a specific European heatwave.

Attribution studies have become an important line of evidence connecting real-world extreme weather with anthropogenic climate change. The review notes that these studies are now part of the evidence base assessed in the IPCC, and that they quantify how climate change alters the likelihood and intensity of extreme events.

The heatwaves experienced since June in western Europe are the clearest signs of global warming caused by human activities, as shown by the various reports from the Intergovernmental Panel on Climate Change (IPCC). Scientific studies have shown that recent heatwaves in Europe would have been highly unlikely without human-induced climate change. As the planet continues to warm, extreme heat events are expected to become more frequent, more intense and longer-lasting.

The Royal Society and the US National Academy of Sciences jointly state that "There is clear evidence that global warming is increasing the likelihood of heatwaves and other extreme temperature events." They explain that as average temperatures rise, the entire distribution of temperature shifts, making extremely hot days much more probable. The document emphasises that while natural variability and regional atmospheric circulation determine the specific timing and location of individual heatwaves, the increased background temperatures due to human greenhouse gas emissions make recent record-breaking heat events more intense and more likely. It cites observational data from Europe among other regions showing substantial increases in the frequency and severity of heatwaves over recent decades consistent with climate model projections of anthropogenic warming.

Reuters reports that scientists with the World Weather Attribution project concluded the heatwave would have been virtually impossible without human-caused climate change, and that climate change made the event far more likely and intense.

Human-caused climate change intensified the recent European heatwave and increased the number of heat deaths by about 1,500 in 12 European cities. Focusing on ten days of heat from June 23 to July 2, the researchers found climate change nearly tripled the number of heat-related deaths, with fossil fuel use having increased heatwave temperatures up to 4°C across the cities. About 1,500 of the 2,300 estimated heat deaths, or 65%, are a result of climate change increasing the heat by 1–4°C, meaning the death toll was tripled due to the burning of fossil fuels.

Climate change is increasing the frequency and intensity of extreme weather events such as heatwaves. Increasingly frequent and intense heatwaves are directly linked to climate change, and they are associated with excess mortality, especially in older people and people with chronic diseases. In Europe and other regions, heatwaves exacerbated by climate change have led to tens of thousands of premature deaths.

The abstract states that a sizable proportion of the excess mortality during the heat waves in the two cities can be attributed to human emissions. It also notes that European heat waves are projected to increase, linking human-caused warming with both impacts and future risk.

Our attribution studies show that human-induced climate change has made UK heatwaves more frequent, intense and long-lasting. For example, the chances of extreme heat events comparable to recent record-breaking UK heatwaves are now several times higher than in the pre-industrial climate. While natural variability and weather patterns still play a role in triggering individual heatwaves, the background warming from climate change is a key factor in their severity.

Whenever an extreme weather event occurs nowadays, the question is invariably asked to which extent the event can be attributed to anthropogenic climate change; was this heat wave less likely in the past? Should such extreme rainfall, in this particular river basin, be expected to intensify in a warmer future climate? The aim of this project is to develop a protocol for these analyses and lay the foundations of an operational service for extreme event attribution under the umbrella of the European Copernicus program. Future analyses using these tools will then benefit from the massive amount of data in the Copernicus Data Store and have the means to construct a transparent, reproducible and well-performing workflow to compute and model climate extremes. Ultimately, these data and tools will accelerate and improve attribution studies, such that the general public can be rapidly and reliably informed about the role of climate change during extreme weather events.

In this interview, atmospheric physicist Dr. Joanna Remiszewska says that "Europe is experiencing one of its most intense heat waves on record" with temperatures surpassing 40°C and explains "why scientists say these extreme conditions would be nearly impossible without climate change." She describes climate change as a scientific fact and states that natural phenomena "are actually being strengthened by climate change" because "we are putting more greenhouse gases into atmosphere, and that's why we are just heating up it." Later in the video she adds that heatwaves in general over Europe "occur earlier than they used to before" and "will hit us more often" and last longer, attributing these changes in timing and frequency to ongoing climate warming.

A communication from ECMWF Copernicus on an ongoing western European heatwave states: "Climate change is driving more intense heat and cold extremes." It highlights that Copernicus datasets allow users to explore more than 80 years of temperature records to see how the distribution of extremes has shifted over time. The post uses the example of current extreme heatwave conditions in western Europe to illustrate how long-term warming trends have increased the intensity of such events compared to past decades.

The IPCC AR6 concludes that human influence has caused observed warming of the atmosphere, ocean and land, and that climate change has already increased the frequency and intensity of hot extremes in Europe. This is high-level synthesis context relevant to European heatwaves, though it is not a single event attribution study.

The post states that human-caused climate change made the record-breaking European heatwave unequivocally more intense, citing a rapid analysis. It is secondary coverage of an attribution result rather than a primary scientific source.