Ice-shelf buttressing

Ice-shelf buttressing is the restraint an ice shelf exerts on the seaward flow of grounded ice. It arises when contact with coastal boundaries or other resisting forces slows the shelf and transmits back stress inland.

Ice shelf: A floating extension of a glacier or ice sheet that remains attached to grounded ice on land. The shelf transfers resistance from its margins and underside to the grounded ice feeding it.
Glacier acceleration: An increase in the speed at which a glacier flows toward its terminus. Grounded glaciers often accelerate after the buttressing of their ice shelves weakens.
Larsen B Ice Shelf: An Antarctic ice shelf that rapidly disintegrated in 2002 after decades of thinning and fracturing. Its collapse was followed by acceleration of glaciers that had flowed into it.
Ice-sheet modeling: The numerical representation of ice flow, mass change, and interactions with the ocean and atmosphere. Models must represent stress transmission accurately to predict the effects of buttressing loss.
Back stress: A stress that opposes the forward motion of a flowing material. Back stress is the force transmitted inland when shelf flow is resisted.
Ice-sheet mass balance: The difference between an ice sheet’s gains from snowfall and losses through melting or ice discharge. Reduced buttressing can increase ice discharge and shift the mass balance.
Pine Island Glacier: A fast-flowing West Antarctic glacier that drains into the Amundsen Sea. Its floating ice shelf provides buttressing that affects the glacier’s discharge.
Ice-shelf–ocean interaction: The exchange of heat, freshwater, and momentum between floating ice shelves and the ocean. Ocean-driven melting can alter shelf thickness and the resistance it provides.
Ice-shelf pinning point: A seabed high or grounded obstacle that locally anchors a floating ice shelf. Pinning points create localized resistance that can strengthen buttressing.
Sea-level rise: A long-term increase in the average height of the global ocean surface. Faster discharge of grounded ice after buttressing loss contributes to sea-level rise.

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