European cities are facing the most severe impacts of climate change, according to a new report by the Lancet Countdown Europe, which analyzed data from 850 cities across the continent. The study reveals that urban areas are increasingly at risk from a range of health threats, including wildfires, the spread of infectious diseases like dengue, and higher pollen levels that worsen allergies. Many cities also act as "heat islands," where temperatures are significantly higher than in surrounding rural areas due to human activity and infrastructure. The report notes that Europe is warming faster than any other region on Earth. Southern Europe, in particular, has seen a dramatic rise in heat-related deaths. Between 1991–2000 and 2015–2024, heat-related mortality in this region increased by 160 percent. In France, the city of Perpignan experienced the largest jump, with heat-related deaths per million inhabitants rising by 1,184 percent. This figure climbed from 10.7 per million in the early 1990s to 139.2 in the most recent period. Other French cities, including Martigues and Toulouse, also saw significant increases in heat-related mortality. In addition to rising temperatures, urban areas are dealing with worsening allergy seasons. Allergenic pollen levels have more than doubled in cities across southern and eastern Europe between the 1990s and the period 2015–2024. This increase is linked to warmer and longer growing seasons, which allow plants to produce more pollen. Some major French cities, like Chambéry, Annecy, and Nancy, experienced over 300 days between 2003 and 2020 where urban temperatures were more than 1.5°C higher than nearby rural areas, highlighting the urban heat island effect. While some cities have started to implement measures like planting more greenery or using reflective surfaces to cool streets, these efforts have not yet been enough to counteract the growing risks. The Lancet Countdown report urges cities to invest more in green spaces, promote active transportation like walking and cycling, and expand public transit networks. These strategies are seen as critical to reducing the health impacts of climate change in urban areas.