ACC News Brief

Climate Science Antarctica

Pine Island ice-shelf regrounding added little drag and may have aided calving

An Antarctic glacier and floating ice shelf meet the dark Amundsen Sea at a fractured calving front.
Image credit: Affect Climate Change Inc. custom editorial artwork; evidence source: Nature Portfolio

What happened

Satellite radar tracking and ice-sheet modeling reveal repeated contact between Pine Island Ice Shelf and shallow bedrock since 2009. The contacts added little extra resistance to ice flow, and the analysis indicates they may instead have helped promote calving between 2015 and 2020, contributing indirectly to the glacier's faster flow over the past decade.

Why it matters

Ice shelves slow the glaciers behind them, but small changes in contact, rifting, and calving can alter that support. Better representation of these mechanics can improve projections for one of Antarctica's closely watched glacier systems and future sea-level rise.

What to watch

  • Whether continued satellite observations detect new regrounding, rifts, or calving changes.
  • How ice-sheet models represent small bedrock contacts and their indirect effects.
  • Whether the shelf's geometry continues to reduce resistance to the glacier upstream.

Sources & evidence

Topics

  • Pine Island Glacier
  • Antarctica
  • Ice Shelves
  • Sea-Level Rise
  • Satellite Science