Shrinking ice shelves

This section is all about ice shelves. Ice shelves are floating ice, connected to the mainland. They receive ice from glaciers flowing into them from the mainland, from accumulation from snow directly onto the ice shelf, and from sea water freezing onto the bottom of the ice shelf. Most mass loss from the Antarctic continent is from ice shelves, and most of this is from just a few small ice shelves around the Antarctic Peninsula and West Antarctica.

Simplified cartoon of a tributary glacier feeding into an ice shelf, showing the grounding line (where the glacier begins to float), the floating ice shelf, and the calved icebergs.

Ice shelves can collapse dramatically. This can occur over just a few weeks, following progressive thinning by warm ocean waters below, and from excessive melting during a warm summer above. If an ice shelf collapses, it changes the boundary conditions for the glaciers that flow into the ice shelf. This means that ice-shelf tributary glaciers accelerate, thin and recede following ice-shelf collapse. So, although ice shelves are already floating and therefore do not contribute to sea level rise when they collapse, ice-shelf removal has significant consequences for the grounded glaciers on the mainland.

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