The summer of 2026 was exceptionally hot across Europe, marked by five severe heat waves and record-high temperatures. This extreme heat is estimated to have caused over 50,000 excess deaths in urban areas. A significant portion, specifically 32,000 fatalities, or nearly two-thirds, are directly attributed to climate change caused by fossil fuel burning. This makes the summer of 2026 likely the "worst on record" for heat-related deaths in much of Europe. These findings stem from two studies published in Nature Health, conducted by Imperial College London and the London School of Hygiene & Tropical Medicine. Researchers analyzed 854 urban areas in 30 countries to estimate heat-related deaths between 2000 and 2026. Official mortality statistics, where available, align with these research estimates. Heat is a major contributor to mortality, stressing cardiovascular and metabolic systems and exacerbating other illnesses. The studies also highlight that while dangerous temperatures would have occurred naturally, human-caused warming significantly amplified the death toll. Temperatures in summer 2026 were 2.9°C above the prior decade's average, with some days 12°C higher. These stark figures underscore the increasing impact of extreme summers on public health and the urgent need to transition from fossil fuels to mitigate future warming.