Home Ice bergs Antarctica lost an ice floe, but gained an island

Antarctica lost an ice floe, but gained an island


The collapse of ice shelves on the east coast of Antarctica has revealed something never seen before: a landform that could be an island. But it’s not the first newly revealed island off the Antarctic coast. A series of islands have appeared as the ice shelves along the mainland’s coastline have disintegrated in recent years.

The island is visible in all three images, which were taken by Landsat satellites between 1989 and 2022. The landform retains its shape, even though the ice around it has melted, shifted and disappeared. As the ice collapsed, scientists believe large icebergs probably crashed on the island, but the island retained its shape.

The east coast of Antarctica has lost most of the Glenzer and Conger ice shelves, as shown in these satellite images taken between November 15, 1989 and January 9, 2022. Credit: NASA GSFC/UMBC JCET.

However, scientists don’t know if there is solid earth under the mound of snow and ice.

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“It is undoubtedly similar to other ice islands, such as Bowman Island (also seen in the image above),” John Gibson, a scientist with the Australian Antarctic Division, said in a post. on NASA’s Earth Observatory. Gibson thinks the feature is likely an ice island: a large, heavy cap of ice sitting firmly on an underwater peak.

Gibson called the ice island “self-perpetuating,” which means that the snow and ice that accumulates on the surface of the island compensates for the amount of melting that occurs underwater. If this balance is disrupted by less snowfall, the ice island could thin and move away. “The unnamed island is a more or less permanent feature of the landscape,” Gibson said, “but may one day break away from the underlying rock and become an iceberg.”

NASA reports that December 2021 elevation data from the Advanced Topographic Laser Altimeter System (ATLAS) on NASA’s Ice, Cloud and Land Elevation Satellite 2 (ICESat-2) shows that at least part of the island is between 30 and 35 meters (100 to 115 feet) above the sea surface.

NASA says most of the Glenzer and Conger ice shelves are gone, after collapsing earlier this year. And with the continued collapse of Antarctica’s ice shelves due to warming oceans, more of these islands could appear.

“The discovery of more of these is expected to continue in the coming years due to shrinking glacial and sea ice,” said Christopher Shuman, a glaciologist from the University of Maryland, Baltimore County, based at Goddard Space. NASA Flight Center. “Obviously these are ‘new to us’ features, but we also have more people and more tools to observe the Antarctic margins now. Several examples do not make a trend, but they imply that d Other once-hidden features are likely to be noticed in years to come.

Learn more about this landform on NASA’s Earth Observatory.