The future response of the Antarctic Slope Current (ASC) to projected transient changes in winds, radiative forcing, and meltwater input is examined in a high-resolution eddy-resolving ocean-sea ice model. Meltwater changes are found to dominate the almost-circumpolar strengthening of the ASC. The strength of the ASC increases non-linearly despite the linear meltwater perturbation applied, with a 9% increase in strength from 2000-2025 contrasting a 71% increase from 2025-2050. This non-linear increase is, however, not seen in the coastal currents on the continental shelf. The non-linear growth of ASC strength is attributed to meltwater accumulating on the continental shelf and poleward shifting warm waters north of the ASC, both triggered by reduced dense shelf water formation, and causing an accelerating ASC through thermal wind balance. Despite the strengthening ASC, any vulnerabilities in the current system could bring poleward shifted warmer waters onto the shelf, with implications for Antarctic ice shelf melt.

Ocean eddies are crucial around the Antarctic margin and there is evidence that they facilitate cross-slope flow of warm water, potentially contributing to ice shelf melt and accelerating sea level rise. However, because eddies around Antarctica are smaller than in other parts of the ocean, these eddies are also more difficult to observe and model. Here we compare the representation of eddies around the Antarctic continental margin in ocean-sea ice models at two different resolutions (1/10⁰ and 1/20⁰), and examine their link to local circulation features. Compared to the 1/20⁰ model, the 1/10⁰ resolution model has stronger shelf currents, especially in East Antarctica, but lower eddy kinetic energy (EKE). On a seasonal timescale, sea ice, EKE and current strength co-vary, with strong correlations on the shelf between current strength and EKE. Current strength and EKE both exhibit prominent seasonal hysteresis, where winter sea ice growth precedes a decline in EKE and current strength, and springtime sea ice decline leads an increase in EKE and current strength. The seasonal link between eddy energy, sea ice and current strength is stronger on the continental shelf than on the slope, and is amplified under higher model resolution. Given how strongly sea ice modulates eddy growth in higher resolution models, a decline in sea ice extent under climate change could greatly increase the projected EKE in models, which could have implications on cross-slope heat transport and thus Antarctic ice shelf melting.