Detection of a Climate Change Signal in Extreme Heat, Heat Stress, and Cold in Europe From Observations

In the last two decades Europe experienced a series of high‐impact heat extremes. We here assess observed trends in temperature extremes at ECA&D stations in Europe. We demonstrate that on average across Europe the number of days with extreme heat and heat stress has more than tripled and hot extremes have warmed by 2.3 °C from 1950–2018. Over Central Europe, the warming exceeds the corresponding summer mean warming by 50%. Days with extreme cold temperatures have decreased by a factor of 2–3 and warmed by more than 3 °C, regionally substantially more than winter mean temperatures. Cold and hot extremes have warmed at about 94% of stations, a climate change signal that cannot be explained by internal variability. The clearest climate change signal can be detected in maximum heat stress. EURO‐CORDEX RCMs broadly capture observed trends but the majority underestimates the warming of hot extremes and overestimates the warming of cold extremes. Key Points We detect a clear climate change signal in extreme heat, heat stress, and cold over Europe that cannot be explained by internal variability On average across Europe, days with extreme heat and heat stress have tripled and days with extreme cold more than halved from 1950–2018 Hot and cold extremes warmed significantly more than the corresponding seasonal mean in Central Europe, by 2.3 and >3 °C, respectively