Attributing temperature extremes in the Euro-Atlantic region to Arctic Sea Ice changes using a framework of conditional extreme event attribution

Over the last century and decades, Arctic climate change has been detected coming along with a rapid decrease of Arctic sea ice extent and a much faster warming of Arctic regions compared to global average. At the same time, an increasing number of record-breaking extreme weather events has been observed also over midlatitudes. In this respect, several studies proposed and studied dynamical Arctic-midlatitude pathways suggesting that Arctic sea ice retreat may not only have local impacts on the polar atmosphere but is also linked to weather and climate in midlatitudes.

In this study, we aim to assess to what extent temperature extremes in the Euro-Atlantic region may be attributed to Arctic sea ice changes. Therefore, in the context of circulation regimes we apply a framework of conditional extreme event attribution to ECHAM6 time slice simulations forced under different sea ice scenarios. As extreme events are generally strongly conditioned and dynamically-driven by specific atmospheric flow configurations, this will help to separate the overall effect induced by Arctic sea ice changes into its thermodynamical and dynamical contributions. This is also motivated by previous studies indicating that sea ice retreat might influence the occurrence probability of certain circulation regimes or blocking patterns and therefore may impact potential dynamical drivers of such extremes.