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A giant iceberg sails towards the open sea after 20 years

A huge and long-lived iceberg located off the Antarctic coast and stranded for more than two decades, in late 2022 began to move towards the open sea.

16 de April de 2023 11:03

Between December 2022 and March 2023, the B-22A moved about 175 kilometers (110 miles).

Now that its proximity to the coast is no longer there, scientists hope to see if the change will affect the nearby Thwaites Glacier, one of the largest contributors to global sea level rise due to the West Antarctic Ice Sheet.

The moving iceberg is known as B-22A . At more than 3,000 square kilometers as of March 2023 , it is the largest remaining piece of the giant iceberg that calved off the Thwaites Glacier in early 2002.

In the decades since it became adrift in the Amundsen Sea, B-22A has remained relatively close to the Thwaites Glacier. It became stuck (on land) in 2012 and has remained parked in a relatively shallow part of the sea a only 100 kilometers (60 miles) from his birthplace; that is, until recently.

In the fall of 2022, Iceberg B-22A broke away from the seabed and began moving northwest. The movement is visible with an animation, made with images from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on satellites. NASA's Terra and Aqua.

The iceberg moving away from the continent between October 24, 2022 and March 26.

“The final movement of Iceberg B22a to completely free itself began today and this simultaneously with the breakup of the sea ice pack in front of the Pine Island glacier. Large chunks of both glaciers threaten to break off,” he described on his Twitter account. the expert on climate change and international climate policy, Kris Van Steenbergen.

It is rare, but not unheard of, for an iceberg to persist for that long. " More than twenty years is a long-lived iceberg, generally speaking," Christopher Shuman , a glaciologist at the University of Maryland, Baltimore County, added in a statement. , based at NASA's Goddard Space Flight Center. Their unmooring is also notable for what it could mean for the future of the Thwaites Glacier.

Icebergs on land play an important role in stabilizing the area's sea ice, which in turn helps reinforce glacial ice on the coast and slow its flow out to sea. While icebergs do not contribute to sea level rise, sea (because they are already floating in the ocean), land ice from glaciers does contribute.

Several factors likely helped the iceberg move again. Shuman said warm waters reaching the Amundsen Sea Inlet have likely been thinning the berg from below since it broke free from Thwaites.Such thinning could have helped it lose contact with the shallow seafloor and allow wind, waves and tides to carry it away.

By mid-April, the polar darkness of Antarctica's southern winter had almost completely enveloped this part of Antarctica.

By Agenda Malvinas


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