Home   News   Article

Subscribe Now

Ice shelf that could be next to collapse ‘has been stable for 10,000 years’ say British Antarctic Survey scientists



More news, no ads

LEARN MORE


The last remaining ice shelf on the eastern Antarctic peninsula has been stable for the past 10,000 years, a new study has shown, but there are signs that it may be next in line to collapse.

Scientists at the Madingley-based British Antarctic Survey have used geological records to reconstruct the history of the Larsen C Ice Shelf.

Larsen C Ice Shelf on the Antarctic Peninsula. Picture: Ali Rose/BAS
Larsen C Ice Shelf on the Antarctic Peninsula. Picture: Ali Rose/BAS

Twice the size of Wales, the ice shelf is the biggest remnant of a much more extensive area of ice on the Antarctic peninsula that began to break up in the 1990s.

The disintegration of the northernmost region, known as Larsen A, in January 1995 was followed by the dramatic collapse of Larsen B in 2002.

Then after a huge rift developed in Larsen C, a vast 5,800 square kilometre iceberg weighing more than a trillion tonnes calved in 2017. It broke up completely in April 2021, after three years drifting from the Antarctic Peninsula to the sub-Antarctic island of South Georgia.

A satellite image of the A68a iceberg from December 2020. Picture: BAS
A satellite image of the A68a iceberg from December 2020. Picture: BAS

Several of the region’s ice shelves have collapsed over the past 25 years. This sequential break-up along the eastern Antarctic peninsula has been linked to global warming, with higher atmospheric temperatures moving southwards over the last half a century.

Warm ocean currents have increased over the same period, which has weakened the ice shelves from below.

Scientists collected seabed sediment cores from beneath Larsen C back in 2011, using hot water drilling technology to penetrate through the 300-metre thick ice shelf.

For their new study, the team combined the findings with data from sediment cores recovered offshore a decade earlier.

This enabled them to reconstruct a detailed history of the ice shelf for the first time.

The study’s lead author, marine geologist Dr James Smith, from British Antarctic Survey, said: “There is a huge international scientific effort under way to get a better understanding of what’s happening to Antarctica’s ice shelves.

“If we can understand what happened in the past we will have a sense of what might happen in the future.

A crack in the Weddell Sea pack ice from 2018. Picture: Susie Grant / British Antarctic Survey
A crack in the Weddell Sea pack ice from 2018. Picture: Susie Grant / British Antarctic Survey

“We can perhaps differentiate natural events that affect the ice shelves from environmental change related to human activity.

This new study provides the final piece of the puzzle to the history of this last remaining ice shelf on the eastern Peninsula.”

“Their findings are concerning, for the researchers conclude that despite modest retreat and advances of the ice shelf front, there has been no significant collapse during the past 10,000 years.

The Larsen C Ice Shelf calved the mighty A68 iceberg in 2017. Picture: European Copernicus Satellite
The Larsen C Ice Shelf calved the mighty A68 iceberg in 2017. Picture: European Copernicus Satellite

The longevity of Larsen C, and Larsen B, suggests these ice shelves were more resilient to past climate warming because they were thicker or may indicate the heat from the atmosphere and ocean did not penetrate this far south.

The 2002 collapse of Larsen B provides a clue that contemporary ice shelf break-ups are now being seen further south than at any point in the past 10,000 years.

And there is good scientific evidence that climate change has caused a thinning of the ice shelf.

Lead author Dr James Smith with a sediment core retrieved from beneath 300 metres of ice on Larsen C Ice Shelf. Picture: Paul Anker/BAS
Lead author Dr James Smith with a sediment core retrieved from beneath 300 metres of ice on Larsen C Ice Shelf. Picture: Paul Anker/BAS

“We now have a much clearer picture of the pattern and extent of ice shelf break-ups, both past and present,” said Dr Smith. “It starts in the north and progresses southward as the atmosphere and ocean warms.

“Should collapse of Larsen C happen, it would confirm that the magnitudes of ice loss along the eastern Antarctic Peninsula and underlying climate change are unprecedented during the past 10,000 years.”

The study was published in the journal Geology.

Read more

Climate change not responsible for world’s largest iceberg, says British Antarctic Survey

British Antarctic Survey scientists lead urgent mission to South Georgia to assess impact of huge iceberg

Emperor penguins from space: British Antarctic Survey uses satellite images to uncover new colonies

First evidence that human-induced global warming has led to melting of West Antarctic Ice Sheet

Sign up for our weekly newsletter and stay up to date with Cambridge science



This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies - Learn More