March 31, 2022 - East Antarctica Ice Shelf Collapse

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It is relatively common for ice shelves in Antarctica to spawn
icebergs. It is less common for an ice shelf to completely
disintegrate. In March 2022, an ice shelf in East Antarctica did both.
The collapse has reshaped a part of the Antarctic landscape where
coastal glacial ice was once thought to be stable. The disintegration
of the entire shelf took just about two weeks. The icy remnants of both
glacial shelf ice and adjacent sea ice dispersed from the waters around
Bowman Island within weeks.

The change happened fast. At the start of March 2022, the floating
shelf fed by the Glenzer and Conger glaciers was still intact. By the
middle of the month, it had fallen apart. This true-color image,
acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS)
on board NASA’s Aqua satellite shows the shelf after it had
disintegrated. Thanks to the NASA Worldview App, a roll-over comparison
of this image and an Aqua MODIS image acquired of the same area on
January 15, 2022—when the ice shelf appeared intact—can be viewed
here

On January 15, the ice shelf floats on the Mawson Sea and appears
solidly attached to the coastline, surrounded by open water as well as
sea ice and ice bergs. Some areas of the ice shelf appear to be pitted
and bits of open water can be seen on the lower right section of the
shelf. The shelf had been noted to be in decline for the last two
years, with scientists estimating that the shelf was losing ice at an
average rate of about 1 square kilometer (1.08 sq. foot) per day
through the natural process of iceberg calving.

In early March 2022, the shelf in front of the Glenzer Glacier calved a
substantial iceberg. Named C-37, the berg initially measured about 144
square kilometers (56 square miles). The substantial loss of ice meant
the shelf disconnected from Bowman Island, although some sea ice
remained attached to the island. Loss of the land anchor on Bowman
Island destabilized the ice shelf, priming it for collapse. Shortly
after, on March 15, a weather system brought high temperatures (40˚C
above normal), enhanced ocean swells, and heavy winds near the ice
shelf. By March 16 the shelf was undergoing its final collapse, and in
doing so it spawned Iceberg C-38, which at the time measured about 415
square kilometers (160 square miles).

The loss of an ice shelf may indirectly contribute to sea level rise,
as the ice shelves serve as ‘safety bands’ protecting the rest of the
Antarctic ice sheet. When an ice shelf collapses, it may allow ice
behind them to flow into the ocean more quickly, increasing the risk of
sea level rise. This particular ice shelf and the surrounding glaciers
are relatively small, so the impact from this solitary event is likely
to be minimal. However, this is the first collapse in East Antarctica,
where scientists have, until recently, considered the ice relatively
stable. The demise of this ice shelf may signal a potential for more
rapid melting of Antarctic ice than expected, leading to faster sea
level rise.

Image Facts
Satellite: Aqua
Date Acquired: 3/21/2022
Resolutions: 1km (43.5 KB), 500m (86.9 KB), 250m (175.5 KB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC



https://modis.gsfc.nasa.gov/gallery/individual.php?db_date=2022-03-31

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