World’s largest iceberg, twice the size of London and two-thirds as tall as the Burj Khalifa skyscraper, breaks free

An iceberg twice the size of London and two-thirds as tall as the world’s largest skyscraper has broken free from the ocean floor and begun moving.

The world’s biggest iceberg is on the move for the first time after being stuck to the ocean floor for 30 years.

The iceberg, called A23a, is 3884 square kilometres in size - twice the size of London - and is headed towards a British island.

It split from the Antarctic coastline in 1986 but was quickly anchored to the ocean floor and essentially became an ice island.

The past year has seen it drifting at speed, and now it is about to leave the Antarctic waters.

But it’s not just the size of the ice island that’s impressive.

A satellite shot of the a23a iceberg from the Copernicus Sentinel 3 satellite.

The slab of ice is 399m thick, which is about two-thirds as high as the world’s tallest skyscraper, the Burj Khalifa in Dubai.

Before it broke off in 1986, it hosted a Soviet research station dubbed “Druzhnaya 1”. Moscow dispatched an expedition to retrieve equipment from the base before it was lost.

But the berg didn’t move far from the coast as its deep keel got stuck in the Weddell Sea’s bottom-muds.

Now the iceberg, driven by winds and currents, is passing the northern tip of the Antarctic Peninsula.

Dr Andrew Fleming, a remote sensing expert from the British Antarctic Survey, told the BBC: “ It was grounded since 1986 but eventually it was going to decrease (in size) sufficiently to lose grip and start moving. I spotted first movement back in 2020.”

Like most icebergs in the Weddell sector, A23a will most likely be thrown into the Antarctic “Circumpolar Current”.

From there, it will be ejected onto a path known as “iceberg alley”.

A satellite shot of the a23a iceberg from the Copernicus Sentinel 3 satellite.

The huge iceberg might be on the path towards a British territory. South Georgia island frequently sees big tabular bergs sitting offshore.

The ice blocks often get pinned on the British Overseas Territory’s shallow continental shelf.

If A23a gets stuck near South Georgia, it might pose a problem for the millions of seals, penguins and other seabirds that inhabit the island.

The megaberg could get in the way of the animal’s normal foraging routes, preventing them from feeding their young properly.

But all icebergs eventually melt and wither away, releasing mineral dust.

And this dust is a source of viral nutrients for the organisms that support the foundation of oceanic food chains.

“In many ways these icebergs are life-giving; they are the origin point for a lot of biological activity,” said Dr Catherine Walker, from the Woods Hole Oceanographic Institution.

The scientists will observe the movement of A23a closely.

This story originally appeared in The Sun and is reproduced here with permission

Originally published as World’s largest iceberg, twice the size of London and two-thirds as tall as the Burj Khalifa skyscraper, breaks free