Der Einfluss des zukünftigen Meereisrückgangs auf Wetterextreme in Europa

The influence of future sea ice retreat on weather extremes in Europe: We investigate how Arctic amplification, and in particular the associated sea ice retreat, can impact cold extremes over Europe. Our investigations are based on climate simulations with a global atmospheric model that is driven by present day and future reduced sea ice conditions. These future sea ice scenarios show no decrease in the frequency of winter cold extremes over Central Europe and even an increase over Eastern Europe. From a purely thermodynamical point of view, however, one would expect a decrease in cold extremes as a result of Arctic warming. Hence, we also considered changes in atmospheric circulation patterns. One of the main results is an increased frequency of high-pressure blocking systems over Scandinavia/Urals in midwinter in the future scenarios.  This circulation pattern is closely linked to more frequent winter cold extremes over Western, Central and Eastern Europe. It is shown that more frequent blockings over Scandinavia/Urals counteract the thermodynamical effect in January and can therefore lead to more frequent cold extremes in the future. However, the effects of future sea ice retreat are of secondary relevance compared to the expected global temperature increase.