Huge ‘mega iceberg’ weighing one trillion tonnes has broken off of Antarctica and is now on a collision course for a tiny island

A humungous 'mega iceberg' known as A23a has got scientists alarmed with it expected to be a collision course with a tiny island in the South Atlantic Ocean.

Weighing a whopping one billion tonnes, the iceberg has been tracked by scientists for years since breaking off from the Antarctic ice sheet back in 1986.

But until 2020, it had been essentially been trapped in a spot of ocean known as the Weddell Sea in the Southern Ocean, where it remained wedged to the ocean floor due to the sheer size of it.

Then five years ago, it broke free - before getting stuck again in 2024. There's a theme here.

Well, last year it was on the move once more and this time in a direction away from the ice sheet for good and in to the South Atlantic Ocean.

And there is a very real worry it will head directly for an island in the ocean known as South Georgia, which itself lies in a space of water known as 'Iceberg Alley'; an area of the South Atlantic Ocean where Antarctica icebergs are pushed north by winds and currents.

And if it does reach the island, it could pose a major problem to life.

Specifically, the life that is born on the island, which is a breeding hotspot for seals, albatrosses, and penguins.

It's a monster (UK MOD Crown Copyright via Getty Images)

That is, according to a new paper from Utrecht University, assessing the dangers of these mega icebergs.

"In 1986, iceberg A23a broke off of the Filchner ice sheet deep in the Weddell Sea," the paper writes. "This super-iceberg remained stuck on the bottom of the shallow Weddell Sea for decades, until it began to drift away in 2020.

"It rode the waves for several years, until it recently set a course for the southern coast of South Georgia.

"Scientists are closely monitoring the iceberg’s progress, because South Georgia is an important breeding ground for colonies of penguins, seals and albatrosses."

The paper adds that if A23a smashed in to the island it could be a nightmare 'blocking countless animals’ access to breeding grounds and foraging waters'.

Penguin chicks after being born on South Georgia Island (Wolfgang Kaehler/LightRocket via Getty Images)

Thankfully, experts believe that is unlikely to happen 'because the island is surrounded by a broad strip of shallow waters, against which A23a would most likely run aground' - so those baby penguins should be alright.

"If that happens, the iceberg’s presence may even have a positive effect on the colonies, as there would be more food to find in the currents moving around the iceberg," the paper adds.

"The ocean’s currents may also guide the iceberg around the island, where it will gradually melt away in the open ocean."