Ocean warming threatens the viability of 60% of Antarctic ice shelves
Summary
This Nature study combines projections of Southern Ocean warming with ice-shelf melt sensitivity to estimate how many Antarctic ice shelves will remain viable as the ocean warms. Using CMIP6-based ocean warming scenarios, multiple basal-melt parameterisations and observational constraints, the authors find that roughly 60% of present-day Antarctic ice shelves could become non-viable under plausible future ocean-warming pathways. Non-viability here means basal melting and associated weakening exceed thresholds that sustain shelf integrity and buttressing of grounded ice.
Key Points
- Approximately 60% of Antarctic ice shelves are projected to become non-viable under realistic ocean-warming scenarios when accounting for basal melt sensitivities and geometry.
- The study uses CMIP6 ocean projections combined with several basal-melt parameterisations to capture model and process uncertainty.
- Ocean-driven basal melting is the principal driver of the projected loss of shelf viability, though surface melt and hydrofracturing remain important locally.
- Loss of ice-shelf viability reduces buttressing, which can accelerate grounded-ice discharge and contribute to sea-level rise over decades to centuries.
- Results vary regionally: some sectors (e.g. Amundsen and parts of West Antarctica) show higher vulnerability due to warm water access and shelf geometry.
- The authors quantify uncertainties and provide datasets and scripts to reproduce figures, improving transparency and model intercomparison.
Content summary
The paper synthesises ocean-warming projections with ice-shelf basal-melt responses to evaluate shelf stability across Antarctica. It examines multiple basal-melt parameterisations and applies them to CMIP6-derived ocean changes to estimate where and when basal melting will undermine shelf viability. The analysis highlights regional differences in vulnerability tied to ice-shelf geometry, ocean access and present-day melt rates. The authors discuss downstream impacts: weaker shelves lead to reduced buttressing, faster glacier flow and raised sea-level contribution risks. They also outline sources of uncertainty — notably differences between melt parameterisations, climate-model spread and local processes like rift propagation and surface hydrofracture — and provide data and code to reproduce their results.
Context and relevance
This work builds on decades of observations and modelling showing ice-shelf thinning and collapse (Larsen, Thwaites, Pine Island, Conger) and places those changes in the context of ocean warming trajectories from CMIP6. It is directly relevant to sea-level projections, Antarctic ice-sheet modelling and adaptation planning. The findings matter for coastal planners, climate policymakers and the glaciology community because ice-shelf loss can unlock enhanced ice discharge and longer-term sea-level rise that is harder to reverse. The study’s transparency (data and scripts available) also helps integrate these results into broader ice-sheet projection efforts.
Why should I read this?
Short version: if you care about sea-level risk or how Antarctica responds to warming oceans, this paper tells you which ice shelves are most at risk and why — saved you time, and it’s a proper heads-up about where things could get messy for global coasts.
Author style
Punchy. The authors make a clear, data-driven argument that ocean warming poses a systemic threat to Antarctic ice-shelf integrity. Because the result — ~60% potential loss of viability — has direct implications for future sea-level rise, the detail is worth digging into rather than skimming.