Tides and Ocean Layering Shape Ice Shelf Melt, Impacting Antarctic Sea-Level Rise Projections

Science Advances, 24 Apr 2026

Observations from the grounding zone beneath the Ross Ice Shelf in West Antarctica show that ocean conditions under the ice are far more dynamic than previously assumed. Instead of a simple two-layer system, warm seawater flows inward beneath the ice while colder, fresher meltwater flows outward above, and these layers shift and mix over time. Ocean tides play a major role in controlling this system, with ice melt increasing significantly during stronger tidal periods and dropping during weaker ones. These short-term fluctuations can triple the rate of ice loss over brief periods; with melting that is not steady, but comes in pulses. Mixing between water layers also moves heat upward toward the ice and increases melting. These fast-changing ocean processes beneath ice shelves need to be taken into account in ice sheet and climate models to better anticipate the rate of future Antarctic ice loss and sea-level rise.

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