An international team of oceanographers, Antarctic specialists and meteorologists has found evidence that the collapse of Antarctica’s Conger ice shelf in 2022 was due to ice melting and weakening that had progressed for decades.
In their study, published in the journal Nature Geoscience, the group analyzed archival satellite imagery of the area prior to the collapse. Karen Alley with the University of Manitoba has published a News & Views piece in the same journal issue, outlining the work by the team on this new effort and explaining why the collapse of the shelf was so alarming to climate scientists.
In 2022, when Antarctica’s Conger-Glenzer Ice Shelf separated from Bowman Island, it was not even noticed for several weeks, until one of the researchers from this new study happened to look at a satellite image of the region. The reason it went unnoticed was no one expected it to separate.
Typically, when an ice shelf is about to break loose, water appears on the surface, evidence of melting. But no water had accumulated on the Conger-Glenzer Ice Shelf, suggesting its separation was different from others in the past.
To find out what happened, the research team pulled up archival satellite imagery of the region. They found the ice shelf had grown increasingly thinner over several decades and eventually became so thin that it lost its integrity. The ice shelf broke away from Bowman Island and was torn apart by waves. The reason researchers had not seen water on top of the ice shelf was it was melting from the bottom—conditions in the eastern parts of Antarctica were still cold enough to prevent the top from melting.
As Alley explains, the reason the Conger-Glenzer Ice Shelf collapse is so concerning is it suggests that East Antarctica ice sheets and shelves may be much closer to melting than previously suspected. And this is important because the amount of ice in the east is far greater than the west, which is where warmer temperatures have been melting top ice. If the ice shelves in the east are melting from below, it could lead to drastically higher ocean levels across the globe.
More information:
Catherine C. Walker et al, Multi-decadal collapse of East Antarctica’s Conger–Glenzer Ice Shelf, Nature Geoscience (2024). DOI: 10.1038/s41561-024-01582-3
Karen E. Alley, Ice-shelf disintegration in East Antarctica, Nature Geoscience (2024). DOI: 10.1038/s41561-024-01607-x
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Antarctica’s Conger ice shelf was weakening for decades before collapse, scientists find (2024, December 4)
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