The Influence of Sea Ice and Ice Mélange on Outlet Glacier Dynamics in the Arctic and Antarctic: Recent Progress and Future Challenges

Abstract Sea ice is situated close to the termini of many outlet glaciers in the Arctic and Antarctic and has the potential to influence their dynamics and, therefore, their contribution to sea level rise. However, the nature, prevalence, and ice‐dynamic significance of sea ice‐glacier interactions remains subject to several open questions. This paper reviews existing research on this critical topic in order to assess the extent to which sea ice influences glacier dynamics, focusing on recent developments while highlighting complexities and uncertainties. Evidence suggests that sea ice can directly influence outlet glacier dynamics through mechanical interactions and/or indirectly via the modulation of ocean‐driven basal melting, either alone or as part of ice mélange. Key knowledge gaps include the influence of mélange‐ocean interactions on glacier melting, and a comprehensive understanding of variations in Antarctic outlet glacier sensitivity to sea‐ice conditions. Current knowledge is skewed toward Arctic outlet glaciers, where the seasonal expansion of sea ice forms a compact mélange which can suppress calving and potentially buttress ice flow. A growing number of studies also suggest that sea ice can influence Antarctic glacier behavior, with observed correspondence between the growth/calving of glacier tongues and ice shelves, and the presence/absence of multi‐year landfast sea ice. However, there is considerable spatial variability in glacier‐dynamic responses to sea‐ice conditions, both within and between the Arctic and Antarctic, predominantly attributed to glacier‐specific factors. Given that recent reductions in sea‐ice extents are likely to contribute to glacier retreat in both polar regions, addressing current knowledge gaps is crucial.