Heatwave–blocking relation change likely dominates over decrease in blocking frequency under global warming

Abstract Extra-tropical continental summer heatwaves often occur under persistent anticyclones or blocking. Here we partition heatwave changes into contributions from blocking changes, heatwave–blocking relation change and mean temperature increase, global warming in climate models. We employ an optimized index that best correlates with (Pearson correlation of 0.7) find heatwave-driving decreases but the likely dominates. Over Europe, a historical frequency 2.5%, less will cause 0.6% fewer heatwaves, steepened 1.4% more increase 60% heatwaves. Greenland, flattened dominate over insignificant decrease The future is not caused by frequency, factors such as thermodynamics, enhance capacity to drive