An iceberg three times the size of Malta, or just smaller than the Isle of Skye in Scotland, broke away from East Antarctica's Amery ice shelf last Saturday.
Up until then, scientists believed another section of the iceberg was due to fall off but were surprised when it was D28 instead.
What happened with D28?
The long overdue separation of the iceberg from the ice shelf caught scientists by surprise. They are part of the Australian Antarctic Program, the University of Tasmania’s Institute of Marine and Antarctic Studies, and the University of California San Diego’s Scripps Institution of Oceanography.
They've all been closely monitoring the Amery ice shelf.
A 1600 km² iceberg broke off Amery Ice Shelf, as seen in @CopernicusEU Sentinel-1 radar images. This part, coined the "Loose Tooth" by @helenafricker and colleagues, has been hanging by a thread since 2002 (https://t.co/IUhXDCWOFF) and finally gave way last week.@sentinel_hub pic.twitter.com/GG60Sk52GB— Bert Wouters (@bert_polar) September 30, 2019
Scientists have long believed that another section of the ice shelf was due to fall off between 2000 and 2015 — a section they named 'Loose Tooth,' for its close resemblance to just that — a loose tooth.
However, the section that did part ways was in a slightly different location.
Scripps' professor Helen Amanda Fricker said, "We knew it would happen eventually, but just to keep us all on our toes, it is not exactly where we expected it to be."
She continued by saying that they were "excited to see this calving event after all these years. It is like expecting a baby tooth to come out and instead out comes a molar."
The last calving event — when an iceberg breaks away from an ice shelf — took place on this ice shelf over 55 years ago, and a similar event was due to happen soon.
The calving was not due to climate change
The scientists who have been studying the Amery ice shelf do not believe this separation is linked to climate change. These researchers believe that it is a natural part of the cycle of the ice shelf.
Losing icebergs is a way in which these ice shelves maintain their equilibrium. It balances out the input of snow being added to the shelf upstream.
Regardless, scientists will keep a close eye on the iceberg as it slowly moves out into the ocean. Their major concern is ensuring it does not get in the way of any shipping streams and damage ships.
Amery Ice Shelf is the third largest ice shelf in Antarctica. The iceberg came from the western part of a rift system at the front of the ice shelf. pic.twitter.com/SUqSPfLC69— Scripps Institution of Oceanography (@Scripps_Ocean) October 1, 2019
Professor Fricker said, "We see major calving events every 60—70 years." So indeed, this massive calving moment was due to happen.
Adding to this, Australian Antarctic Program glaciologist Dr. Galton-Fenzi said, "The calving will not directly affect sea level, because the ice shelf was already floating, much like an ice cube in a glass of water."
Galton-Fenzi continued, "But what will be interesting to see is how the loss of this ice will influence the ocean melting under the remaining ice shelf and the speed at which the ice flows off the continent."