Amundsen Embayment = mass loss hotspot
Mass loss in AntarcticaHotspots of change
Pine Island Glacier
and Thwaites Glacier in the Amundsen Sea Embayment are among the fastest
changing outlet glaciers in West Antarctica with large consequences for global
sea level.
Before/after view
Antarctica with/without ice
Pine Island and Thwaites Glacier have retrograde beds below sea level which makes them prone to marine ice sheet instability
Sea level rise potential
Over the past 40 years Pine Island and Thwaites Glacier have contributed ~5 mm to global sea level rise.
However, when retreating further, they could destabilize the entire West Antarctic Ice Sheet, which contains enough ice to raise sea level by ~3.4 m.
However, when retreating further, they could destabilize the entire West Antarctic Ice Sheet, which contains enough ice to raise sea level by ~3.4 m.
How much? How fast?An uncertain future
Yet, projecting the future of these glaciers remains
a major uncertainty as many of the processes that control their retreat are poorly understood or quantified.
Satellite observations
Damage accelerates mass loss
In this study, we
identify damage processes that might be crucial to the future
of both glaciers. Evidence of this damage consists of highly crevassed areas and open fractures on their ice shelves.
Tearing an ice shelf apart
Satellite time series show the rapid evolution from lack of crevasses to highly damaged shear zones during recent years.
Preconditioned for disintegration
We
hypothesize that this damage preconditions these ice shelves for further
disintegration. First, because it already compromises the integrity of both ice shelves.
Unprecedented retreat
An example of this preconditioning can be seen in the unprecedented retreat of the ice shelf front over the last years.
More sensitive
Second, because the weakening due to damage makes the future response of both ice shelves more sensitive to varying and extreme future atmospheric,
oceanic, and sea ice conditions.
Damage feedback
Third, because the damage initiates a feedback process, where damage enhances speedup,
shearing, and weakening, hence again promoting additional damage.
Modelling damage
Modelling damage impact
To assess the importance of this damage feedback, we ran an ice sheet model in an idealized setup with different weakening scenarios.
Damage accelerates mass loss
The model results highlight the importance
of the damage feedback as a driver for ice shelf instability and grounding line retreat through time.
Implications
Damage implications
This illustrates that weakening these glaciers at their most vulnerable locations, as can be currently observed in the satellite observations, is a very effective way of causing additional grounded ice mass loss from Pine Island and Thwaites glaciers.
Damage implications
This implies that these damage areas close to the grounding lines could have important implications for future mass loss.
It also underlines the need for incorporating these feedback processes, which are currently not accounted for in most ice sheet models, to improve sea level rise projections.
It also underlines the need for incorporating these feedback processes, which are currently not accounted for in most ice sheet models, to improve sea level rise projections.
Acknowledgements
More info?
This research is the result of a team effort on an international team consisting of Stef Lhermitte (TUDelft), Sainan Sun (ULB), Christopher Shuman (UMBC/NASA), Bert Wouters (TUDelft/IMAU), Frank Pattyn (ULB), Jan Wuite (Enveo),
Etienne Berthier (CNRS) and Thomas Nagler (Enveo).
We gratefully acknowledge NWO, NASA, CNES, ESA, NSIDC, Enveo and the European Commission for their support via funding or as a data provider.
We gratefully acknowledge NWO, NASA, CNES, ESA, NSIDC, Enveo and the European Commission for their support via funding or as a data provider.
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Mass loss in Antarctica
Sea level rise potential
How much? How fast?
Damage accelerates mass loss
Tearing an ice shelf apart
Preconditioned for disintegration
Unprecedented retreat
More sensitive
Damage feedback
Modelling damage impact
Damage accelerates mass loss
Damage implications
Damage implications