That matters because when ice shelves thin, crack or weaken, they can lose some of that holding power. More land ice can then move toward the sea, adding to long-term sea-level rise.
A new modeling study of the Fimbulisen Ice Shelf in East Antarctica suggests one hidden feature could make these shelves more fragile than expected: channels carved into the underside of the ice.
These channels are like grooves or ditches on the bottom of the ice shelf. Scientists have known about them for years, but their role in melting has been harder to pin down, especially in colder parts of Antarctica where ice shelves were often seen as less exposed to warm-water melt.
The study found that even modest amounts of warmer deep ocean water can create problems when they move into these under-ice channels.
Instead of simply flowing past, the warmer water can become trapped inside the grooves. Once there, it melts the ice from below much faster than it would under a smoother section of ice.
In the simulations, some deep channels saw melt anomalies of more than 10 meters per year under warmer conditions. As the channels melt and deepen, they may also become better at holding more warm water, creating a feedback loop that can increase local melt over time.
The takeaway is not that every cold Antarctic ice shelf is at immediate risk. But the study does suggest that some East Antarctic shelves may be more sensitive to modest ocean warming than current broad models show.
For coastal planners, insurers, infrastructure owners and climate-risk teams, the finding is a reminder that sea-level projections are not just shaped by big-picture warming trends. Small features hidden beneath the ice can also affect how quickly and where Antarctic ice weakens.
