Sea ice has exhibited large variability over recent decades albeit with pronounced differences between the two poles. Superimposed on the long-term declining trend in Arctic sea ice, years with enhanced sea ice loss between 2007 and 2012 were followed by a now decade-long pause without a new record minimum. As for Antarctica, an increase in sea ice variability has been observed with anomalous high values followed by anomalous lows. The 2016 absolute maximum and the 2023 new record minimum followed by the approx. one-month delay in refreezing are prime examples. Capturing the sequence of these events in climate models is still challenging and, although rapid changes are already underway, our understanding of the drivers of extreme sea ice behavior is still incomplete. In this seminar I will review the driving mechanisms of Arctic/Antarctic sea ice variability with focusing on large-scale atmospheric variability and tropical-high latitude teleconnections. Two case studies are presented, one for the Arctic and one for the Antarctic. What did we learn when comparing observed and modelled sea ice sensitivities to high-altitude winds in terms of the projections of an ice-free Arctic? How unusual was the ~1 month delay in Antarctic ice growth during the austral spring/autumn in 2023?