Western and central Europe are currently enduring a heatwave described as the hottest and most humid ever recorded on the continent. A recent study by the World Weather Attribution network of scientists has concluded that these extreme temperatures would have been virtually impossible in the absence of climate change, definitively ruling out other factors such as a potential 'super El Niño'.
The research analysed the likelihood of the average daily maximum temperatures projected for 26 to 28 June if climates were similar to those of 1976 or 2003. It found that while the specific weather pattern – a low-pressure heat dome trapping hot air from the south – is not unusual, the intensity of the temperatures is. Fifty years ago, a typical June heatwave would have been approximately 3.5°C cooler, and the temperatures observed this week would have been an event occurring less than once in 10,000 years.
This heatwave has seen daytime temperatures soar above 44°C in parts of France, while nighttime temperatures have remained stubbornly above 30°C in areas of Spain. Theodore Keeping of Imperial College London highlighted the severity, stating, "This event would not have been possible in June without climate change. The three-day nighttime temperatures would not have been possible at any time of year without climate change."
Adding to the danger is the unprecedented humidity, which has reached over 50 per cent in many British cities. Dew-point temperatures have been in the low 20s, significantly higher than the single digits recorded during the UK's record-breaking July 2022 heatwave. This elevated humidity is particularly concerning as it impedes the body's natural cooling mechanism by slowing sweat evaporation, thereby increasing health risks. The wet-bulb globe temperature, a comprehensive measure accounting for air temperature, humidity, heat radiation, and air movement, is expected to break records in nearly half of European cities.
The health implications are expected to be substantial, especially for vulnerable groups such as the elderly, individuals with chronic illnesses, migrants, and those experiencing homelessness. Friederike Otto, also from Imperial College London, underscored the unequal impact, noting, "What we see very clearly… is how unequal the effects of this heatwave are and how that really demonstrates the inequality that widens due to climate change." While a full assessment of excess mortality is pending, a previous, less intense heatwave in June and July 2022 was linked to 2,300 deaths across London and 11 other European cities. The researchers stress that without rapid reductions in fossil fuel emissions, such heatwaves will become even more frequent and intense, exposing Europe's largely unprepared, ageing, and urban population to greater risks.