Feedback attribution to recent Arctic temperature extremes and the role of natural variability

Abstract The polar regions have been undergoing amplified warming in recent years. However, natural climate variability can further amplify or dampen the ongoing warming trend causing extreme temperature events. Therefore, it is important to determine the role of climate variability on shaping the characteristics of extreme temperature events. By employing a surface radiation budget framework, we examine the main causes for Arctic amplification and extreme summer temperature events over the period 1979-2021, considering feedback attribution analysis and natural climatic modes. The results demonstrate that increases in clear-sky longwave radiation explain most of the temperature trend, with the surface albedo feedback and changes in ocean heat storage playing a supporting role. Regarding recent extreme temperature events on inter-annual time scales, climate variability such as the North Atlantic Oscillation and the Greenland Blocking Index has exerted a significant impact on such extreme events by modulating the feedback strength. Furthermore, we find that extreme temperature events can be explained in large part by anomalous atmospheric circulation related to strengthened blocking anti-cyclones associated with the Greenland Blocking Index.