First major chunk breaks off world's biggest iceberg

AFP
Fri 31 January 2025 


The world's largest iceberg has stayed largely intact as it has drifted through the ocean but scientists say a piece 19 kilometres (12 miles) long has now cleaved off (Handout) (Handout/NASA/AFP)


An enormous chunk has broken off the world's largest iceberg, in a possible first sign the behemoth from Antarctica could be crumbling, scientists told AFP on Friday.

The colossal iceberg -- which is more than twice the size of Greater London and weighs nearly one trillion tonnes -- had largely stayed intact since it started slowly moving north in 2020.

It has been drifting toward the remote island of South Georgia in the South Atlantic, raising the prospect it could run aground in shallower water and disrupt feeding for baby penguins and seals.

But a chunk about 19 kilometres (12 miles) long has cleaved off, said Andrew Meijers from the British Antarctic Survey, who encountered the iceberg in late 2023 and has tracked its fate via satellite ever since.

"This is definitely the first significant clear slice of the iceberg that's appeared," the physical oceanographer told AFP.

Soledad Tiranti, a glaciologist currently on an Argentinian exploration voyage in the Antarctic, also told AFP that a section had "broken" away.

The jagged piece has an area of roughly 80 square kilometres (31 square miles) -- huge in its own right, but just a fraction of the approximately 3360 square kilometres that remained.

Meijers said icebergs were full of deep fractures, and although this monumental specimen had shrunk over time and lost a much smaller piece, it had "held together pretty nicely".

"This is a sign that those rifts in it are starting to break up," he said.

In the past, other mega-icebergs had fallen apart "relatively quickly over the course of several weeks" once they started losing big pieces, he said.

It was hard to say if this was "a loose tooth just waiting to come out" or evidence of a much bigger change underway.

"I'm sorry to say but it's not really an exact science how these things fall apart... it's really hard to say if this is going to blow apart now, or it's going to hang together for longer," Meijers said.

Known as A23a, the world's biggest and oldest iceberg calved from the Antarctic shelf in 1986.

It remained stuck for over 30 years before finally breaking free in 2020, its lumbering journey north sometimes delayed by ocean forces that kept it spinning in place.

This monster block of freshwater was being whisked along by the world's most powerful ocean "jet stream" -- the Antarctic Circumpolar Current.

Meijers said its trajectory toward South Georgia, a crucial feeding ground for seals and penguins, would unlikely change because it had lost this chunk.

But should it collapse further it would pose "much less of a threat for wildlife" because foraging animals could manoeuvre unimpeded between the smaller chunks to find food, he added.

Icebergs had grounded there in the past and caused significant mortality to penguin chicks and seal pups.

Tiranti said the iceberg was expected to keep plodding its way north but its exact course depended greatly on how local currents influenced its movements.

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What we know about iceberg A23a and its collision course with a remote British island

Iceberg A23a is on a collision course with the remote British island of South Georgia, which provides an Antarctic haven for penguins and seals.

Rob Waugh
·Contributor
Updated 24 January 2025·

The iceberg is around three times the size of the Peak District. (Getty)


The world’s largest iceberg is heading towards a remote British island of South Georgia in the South Atlantic Ocean and could threaten millions of penguins and seals that live there.

The huge iceberg A23a measures almost 1,500 square miles, roughly twice the size of Greater London, and is as tall as the Shard in London.

Dr Andrew Meijers, physical oceanographer at British Antarctic Survey told Yahoo News that the collision may have a deadly impact on baby seals and penguins.

After the iceberg broke off from one of the ice shelves four decades ago, it immediately grounded on the shallow ocean bottom. It has since spent three years slowly meandering northwards.

Millions of penguins and seals live on South Georgia. (Getty)

"It wasn’t until the end of 2023, that it came out, and that was when I encountered it on a research vessel," Dr Meijers said.
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Millions of seals, penguins, and seabirds breed on South Georgia and forage in the surrounding waters.

Dr Meijers said: "People might be worried that it's likely to come into contact with South Georgia in the next two or four weeks. South Georgia is home to fur seals and penguins, and currently, they're in the middle of their breeding.

"So if it grounds, it will disrupt their access to food supplies, which means a lot of the chicks and pups are likely to die. That’s on top of a bad season already, because bird flu is affecting seals and penguins in the region.

When did iceberg A23a break off?

(Getty)

The iceberg calved off West Antarctica's Filchner-Ronne Ice Shelf in 1986 and previously hosted a Soviet research station.

For many years, it was stranded after its base became stuck on the floor of the Weddell Sea but in 2023 it broke off and started moving until it eventually passed the northern tip of the Antarctic Peninsula.

"It is presently in a meander of the current and not moving directly towards the island," Dr Meijers said. "But our understanding of the currents suggest that it is likely to again move towards the island soon.

Experts now fear the iceberg could stop seals and penguins feeding in South Georgia. (Getty)

"The current follows the shallow continental shelf around the island to the southeast, but the question is whether the berg will follow this out into the open South Atlantic, or run up onto the shelf and become stuck for some time."
Why does it pose a threat to South Georgia?

The iceberg could ground against the island, meaning that the many seals and penguins which live there could be unable to access food.

The iceberg is currently 173 miles away from the island, according to the BBC.

Cruise ship passengers look at A23a in December 2023. (Getty)

Large slabs of ice are already breaking off A23a, and experts fear it could break into segments which could hang around South Georgia for years.

"If this happens it could seriously impede access to feeding grounds for the wildlife - seals and penguins mostly - that breed on the island," Dr Meijers explained.

In 2020, another gigantic iceberg, A68, stirred fears that it would collide with South Georgia.

Researchers feared that the iceberg would end up crushing marine life on the sea floor and cutting off food access, but the iceberg eventually broke into smaller chunks.
What is causing this?

The root cause of the melting of such huge icebergs is climate change, Dr Meijers said. "This iceberg is a natural phenomenon, but it really does represent an increase in the ice loss of Antarctic ice shelves.

"Since 2020, the ice shelves have lost six trillion tons of ice. They've gotten smaller by then amounts, and that's due to climate change."