Unprecedented Europe Heat in June-July 2019: Risk in the Historical and Future Context

Western-central Europe experienced the most severe June-July heat on record in 2019, with several heatwaves occurring over the most densely populated regions. Highest 3-day averaged daily mean temperature in June-July averaged over the region exceeds normal by 4.7 degrees C, which is estimated to be a 1-in-283-year event over the 1950-2014 climate. The driver and future likelihood of this extreme heat in a changing climate have drawn extensive attention. Based on the newly released climate model data from the sixth Coupled Model Intercomparison Project (CMIP6), we find that anthropogenic climate change has caused a sevenfold increase in the likelihood of the extreme heat over 1950-2014 climate, and even a 23-fold increase since 1980s. Such extreme heat will become more frequent in the future, with return periods of 1.8-7.2 years under future emission and societal development scenarios. Without sufficient adaptation strategies, such extreme heat would become more widespread, long-lasting, and severe over Europe.