The world’s largest iceberg is on the move: Huge trillion-ton ‘megaberg’, twice the size of Greater London, has broken free – and is now floating in the Southern Ocean

The world’s largest iceberg is officially on the move.

A23a is twice the size of Greater London and weighs almost a trillion tonnes.

The mega mountain has been on the seabed for more than 30 years and recently started spinning on site.

Now experts from the British Antarctic Survey (BAS) have confirmed that A23a has finally broken free from its position north of the South Orkney Islands.

It now begins a new journey as it begins to drift in the Southern Ocean.

“It is exciting to see the A23a moving again after a period of stalling,” said Dr. Andrew Meijers, oceanographer at BAS.

‘We are curious to see if it will follow the same route as the other large icebergs that have calved off the coast of Antarctica.

‘And more importantly: what impact this will have on the local ecosystem.’

The megamountain has been on the seabed for more than 30 years and recently began rotating on the spot. Now experts from the British Antarctic Survey (BAS) have confirmed that A23a has finally broken free from its position north of the South Orkney Islands

A23a is about double the size of Greater London and weighs almost a trillion tonnes

The iceberg originally calved from the Filchner Ice Shelf in Antarctica in 1986.

It then remained grounded in the Weddell Sea before beginning its slow journey north in 2020.

In February this year, the iceberg became stuck in a Taylor Column – a phenomenon in which rotating water above an undersea mountain holds objects in place.

This left the A23a running in place, delaying the expected rapid drift northwards.

Now images taken by satellites above us have confirmed that the iceberg has broken free.

BAS experts now expect it to continue its journey into the Southern Ocean, following the Antarctic Circumpolar Current.

This will likely push it towards the sub-Antarctic island of South Georgia.

Warmer conditions in that region will likely lead to the breakup of A23a into smaller icebergs, which will eventually melt.

The iceberg originally calved from the Filchner Ice Shelf in Antarctica in 1986. It then remained grounded on the seabed in the Weddell Sea before beginning its slow journey north in 2020.

In February this year, the iceberg became stuck in a Taylor column – a phenomenon in which rotating water above an undersea mountain holds objects in place

In addition to the satellites, the megamountain is being studied by researchers aboard RRS Sir David Attenborough.

Laura Taylor, a biogeochemist aboard the ship, hopes to study the iceberg’s impact on local ecosystems.

She said:We know that these giant icebergs can provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less productive areas.

‘What we don’t know is what difference certain icebergs, their size and their origin can make to that process.

‘We took samples of the surface water of the ocean behind, immediately next to and in front of the iceberg’s path.

“They should help us determine what life might form around A23a and how this affects the ocean’s carbon and its equilibrium with the atmosphere.”