Arctic sea-ice decline amplifies extreme wave exposure for coastal Inuit communities

The ongoing reduction of seasonal sea ice in the Arctic enhances the development of extreme wave conditions, increasing the exposure of coastal communities to storm-related hazards. It is particularly prominent in Ausuittuq, Nunavut, the northernmost civilian community in Canada, which has experienced repeated coastal flooding over the past decade. In this study, we reconstruct a 38-year time series of total water level (TWL) in Ausuittuq to quantify the relative contributions of tides, storm surge, and wave runup to historical extremes. Wave runup contributes ~30% of annual maximum TWL and directly drives 25% of extreme events. Future mean and extreme wave conditions are assessed using a locally calibrated parametric wave model forced with CMIP6 projections of wind and sea ice. By mid-century, the projected lengthening of the ice-free season —particularly the delayed autumn freeze-up— substantially increases the frequency of extreme wave events by 53% under SSP2-4.5 and 75% under SSP5-8.5 relative to 1985–2000. By 2100, the frequency of extreme wave events under SSP5-8.5 approaches levels comparable to an entirely ice-free year. It suggests that in fetch-limited, seasonally ice-covered Arctic regions, sea-ice loss amplifies hazard exposure primarily through more frequent wave extremes, signaling a shift toward more persistent wave-driven coastal hazards.