Ice Cliff Collapse May Not Occur so Rapidly in the Near-Term, but Risks of Major Sea-Level Rise Remain

Science Advances, 21 August 2024

The collapse of ice shelves around Antarctica could expose tall ice cliffs at the edge of the ice sheet. Some models have shown that once the protective ice shelves are lost, these cliffs may fail structurally and collapse, leading to rapid ice loss and extremely fast rates of sea-level rise. This study, using detailed models of the ice sheet, instead showed that the ice rapidly thins and flows faster following ice shelf loss, stabilizing the cliff and slowing resulting ice loss. As a result, the initiation of such rapid rates of sea-level rise in the coming decades would not occur because of this cliff collapse process alone. However, authors emphasize that the West Antarctic Ice Sheet is not stable, and subject to other self-reinforcing processes — some of which scientists have only just discovered — that could still lead to high rates of sea-level rise lasting for centuries. The complexity of these findings makes clear that more research is badly needed to understand these near-term and long-term risks; and that only immediate cuts in fossil fuel emissions, staying within the lower 1.5°C Paris Agreement limit, will minimize chances of triggering catastrophic processes before we have the tools to understand them.

Full paper: https://www.science.org/doi/10.1126/sciadv.ado7794
News briefing: https://www.nytimes.com/2024/08/21/climate/antarctic-ice-cliff-collapse.html