Reversibility of European Heatwaves in a CO₂ Removal Scenario

다국어 초록 (Multilingual Abstract)

Europe has experienced severe extremes more frequently since the 21<SUP>st</SUP> century. In terms of heatwave, it is expected to increase in frequency, intensity, and duration in an enhanced warming world. To investigate the reversibility of European heatwaves, we performed a CO₂ removal experiment using an Earth system model, in which the CO₂ concentrations are ramp-down returned to the present-day(PD) level, referred to as a Restoring period (RP), after reaching the ramp-up toward CO₂ quadrupling. As a result, the changes in heatwave characteristics have a difference by regions. Compared to the PD, annual heatwave days of RP are increased twice over around the UK, whereas more than half of events are decreased in Central Eastern Europe. The changes of average daily maximum temperature in both areas are also quite different. Overall, change of the heat wave characteristics over Southern Europe follows directly the CO₂ level changes, while that over the UK is likely influenced by the enhanced anomalous North Atlantic warming associated with the overshooting of Atlantic Meridional Overturning Circulation (AMOC) at the end of the ramp-down period. Our results help in understanding regional different heatwave trends in the Future.