The recent heatwave in Europe has shattered records, with peak temperatures surpassing those from the 1970s. This extreme weather event is a stark reminder of the accelerating climate crisis and its devastating impacts. As John Kennedy, head of climate information at the World Meteorological Organization (WMO), aptly states, "Heatwaves like this are what we expect to see in a changing climate." Europe's rapid warming, having increased by around two degrees since 1976, is a cause for grave concern. The highest sea surface temperatures on record for June, as reported by the Copernicus Climate Change Service, are driving these heat spikes. This is a global phenomenon, with the monthly average sea-surface temperature for the extra-polar ocean (60°S-60°N) reaching unprecedented heights in June, just 0.01°C above the previous record set in June 2024. The consequences of this extreme heat are far-reaching. It has led to severe health impacts, including heat-related deaths, which have been under-reported in many countries. More than 200,000 heat-related deaths occurred in Europe over the past four years, according to the World Health Organization (WHO), and globally, WMO estimates approximately 489,000 heat-related deaths annually between 2000 and 2019. The vulnerable populations at risk include older adults, young children, pregnant women, outdoor workers, and people unhoused or living with chronic illnesses. However, as Lachlan McIver, a health adviser at the WHO-WMO Climate and Health Joint Office, emphasizes, heat stress can affect anyone when temperatures are extreme enough for long enough. One of the most alarming aspects of this heatwave is the persistence of "tropical nights." A "tropical night" occurs when the temperature does not drop below 20°C, and these nights are becoming increasingly common during heatwaves, particularly in cities. As Armel Castellan, an extreme heat services technical advisor at the WMO-WHO Climate and Health Joint Office, notes, "When assessing the health impact of a heatwave, minimum temperatures can be more telling than the peak afternoon high." This is because a day that reaches a high temperature but drops to a low temperature overnight poses a higher health risk than a day that stays above a certain temperature throughout. The WMO, along with other UN entities, is actively working to combat the impacts of extreme heat. They are supporting the Secretary-General's Call to Action on Extreme Heat, which aims to strengthen international cooperation and reduce heat impacts through improved science, early warning systems, public awareness, and coordinated action. The UN weather agency and its partners are mobilizing with early warnings and coordinated action plans to save lives and minimize economic and ecosystem damage. In addition, the UN health and weather agencies have launched updated heat-health action guidance to help nations and communities cope with extreme temperatures. The WMO is also compiling a regularly updated snapshot of temperature records, highlighting the unprecedented nature of the heatwave in Europe. For instance, Denmark recorded a new all-time high of 37.0°C in two locations, breaking a record set in 1975. France saw its average national temperature reach 30.0°C on June 24, with a peak temperature of 43.8°C in Pulluau and overnight temperatures setting a new national record of 22°C. The Netherlands, Spain, and Switzerland also experienced record-breaking temperatures, with Spain's Bilbao reaching 42.7°C, the highest ever recorded there. These record-breaking temperatures underscore the urgent need for action to mitigate the impacts of climate change and protect vulnerable populations from the devastating effects of extreme heat.
