Feedback loop between Arctic sea-ice decline and eddy dynamics: Lessons from an ultra-high resolution climate model

Abstract The Arctic sea ice is vanishing at an alarming pace, far outstripping the predictions of many current climate models (Shu et al., 2020). This growing discrepancy suggests that vital oceanic processes—especially (sub)mesoscale eddies responsible for heat transport to the sea ice—are not being fully captured. In this study, we leverage a cutting-edge, coupled ocean-sea ice model with an unprecedented 2 km eddy-resolving resolution, spanning 1980 to 2100, to explore how oceanic eddies are driving the dramatic loss of Arctic sea ice. Our findings reveal that eddy-driven processes are playing an increasingly dominant role in sea ice decline, with their most profound impact occurring in the final decades of the 21st century. The main driver of this intensifying trend is the transport of heat to the ice-ocean interface by oceanic eddies, particularly in the marginal ice zones. We further propose that a self-amplifying feedback loop between sea ice loss and eddy dynamics is at play, accelerating the melting process. These results highlight the urgent need to integrate eddy dynamics into future Arctic sea ice models, especially as the region undergoes rapid transformation in a warming climate.