Changes in ice dynamics and mass balance of the Antarctic ice sheet

• Main Author: Rignot, Eric
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2006
• Subjects: Climate Action; Antarctica; interferometry; Southern Ocean; polar climate; General Science & Technology; Antarctic; Antarctic Peninsula; Cook Ice Shelf; East Antarctica; Island Bay; Pine Island Bay; Pine Island Glacier; The Antarctic; Thwaites Glacier; West Antarctica; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves; Pine Island
• Online Access: https://escholarship.org/uc/item/59n371j2

The concept that the Antarctic ice sheet changes with eternal slowness has been challenged by recent observations from satellites. Pronounced regional warming in the Antarctic Peninsula triggered ice shelf collapse, which led to a 10-fold increase in glacier flow and rapid ice sheet retreat. This chain of events illustrated the vulnerability of ice shelves to climate warming and their buffering role on the mass balance of Antarctica. In West Antarctica, the Pine Island Bay sector is draining far more ice into the ocean than is stored upstream from snow accumulation. This sector could raise sea level by 1m and trigger widespread retreat of ice in West Antarctica. Pine Island Glacier accelerated 38% since 1975, and most of the speed up took place over the last decade. Its neighbour Thwaites Glacier is widening up and may double its width when its weakened eastern ice shelf breaks up. Widespread acceleration in this sector may be caused by glacier ungrounding from ice shelf melting by an ocean that has recently warmed by 0.3 degrees C. In contrast, glaciers buffered from oceanic change by large ice shelves have only small contributions to sea level. In East Antarctica, many glaciers are close to a state of mass balance, but sectors grounded well below sea level, such as Cook Ice Shelf, Ninnis/Mertz, Frost and Totten glaciers, are thinning and losing mass. Hence, East Antarctica is not immune to changes.