Future Irreversible Ice Loss in East Antarctica Accelerated by Subglacial Hydrology

Subglacial hydrology significantly influences future sea-level rise through its impacts on ice sliding, yet remains one of the least constrained factors in Antarctic ice-sheet projections. Here, we employ a fully coupled ice sheet–hydrology model of the Wilkes Subglacial Basin in East Antarctica—a largely understudied but vulnerable region holding 3–4 meters of sea-level equivalent—to explore the impact of ice–subglacial hydrology interactions on ice sheet mass loss. Our results indicate that ice–subglacial hydrology interactions amplify mass loss from the Wilkes Basin by ~75% by 2500 relative to an otherwise identical simulation held at static subglacial conditions, giving a sea-level contribution of ~0.39 m under a very-high emissions scenario. In idealised mitigation experiments a critical threshold is identified around 2200: when the forcing is subsequently reduced, retreat continues and the grounding line does not re-advance, indicating that mass loss becomes self-sustaining and effectively irreversible on centennial timescales. The irreversible phase is characterised by accelerated ice flow and subglacial water piracy toward Cook Glacier. Simulations based on commonly used simplified hydrology parameterizations typically underestimate both the magnitude of ice loss and rapid onset of tipping relative to fully coupled models, with discrepancies largely governed by distinct bed morphology assumptions. Our findings underscore the importance of dynamic subglacial hydrology for Antarctic ice sheet projections, and highlight the need for targeted observations and model development to reduce uncertainties in ice-loss estimates from regions with substantial subglacial meltwater production.