The world's largest iceberg runs aground, sparing an island of wildlife March 4, 2025

The movement of iceberg A23a until February 28, shortly before it became trapped (Jean-Michel CORNU) (Jean-Michel CORNU/AFP/AFP)

By AFP - Agence France Presse

The world's largest iceberg runs aground, sparing an island of wildlife

Daniel Lawler

The world's largest iceberg appears to have run aground about 70 kilometers from a remote Antarctic island, potentially sparing the crucial wildlife haven from being hit, a research organization said Tuesday.

The colossal A23a iceberg - which is more than twice the size of Greater London and weighs almost a trillion tons - has been moving north from Antarctica towards South Georgia Island since 2020.

This has led to fears that it could collide with the island or run aground in shallower waters close to it, which could harm the ability of penguins and seals to feed their chicks.

However, the gigantic wall of ice has been stuck 73 kilometers (45 miles) from the island since March 1, according to a statement from the British Antarctic Survey (BAS).

“If the iceberg remains stranded, we do not expect it to significantly affect local wildlife,” said BAS oceanographer Andrew Meijers.

“In recent decades, the many icebergs that end up taking this route through the Southern Ocean soon break up, disperse, and melt,” added Meijers, who found A23a at the end of 2023 and has followed its fate via satellite ever since.

Satellite images analyzed by AFP showed that the nearest edge of the iceberg had stopped more than 70 kilometers from the island at the end of February.

It is not yet clear whether the iceberg is permanently trapped.

“It will be interesting to see what happens now,” added Meijers.

- Possible advantages for wildlife?

The world's largest and oldest iceberg broke off from the Antarctic shelf in 1986.

It remained trapped for more than 30 years before finally breaking free in 2020, its heavy journey north sometimes delayed by the oceanic forces that kept it spinning in place.

Satellite images had previously suggested that it wasn't disintegrating into smaller pieces along the familiar path these icebergs take. However, a 19-kilometer chunk broke off in January.

There were concerns for wildlife in South Georgia's crucial breeding area if the iceberg stalled too close.

This would have forced animals such as penguins and seals to travel much further to get around the colossal block of ice.

“This could reduce the amount of food reaching the island's chicks and young, increasing mortality,” explained Meijers.

However, in its current location, the iceberg can offer benefits to wildlife.

The nutrients stirred up by the grounding (of the iceberg) and its melting can increase the availability of food for the entire regional ecosystem, including the charismatic penguins and seals,” said Meijers.

South Georgia's seal and penguin populations have already had a “bad season” due to an outbreak of bird flu, Meijers told AFP in January.

- What about climate change?

The iceberg poses no threat to navigation. It is so large that ships can easily avoid it.

However, as it fragments into smaller pieces, certain areas could become off-limits to commercial fishing vessels “due to the number of smaller but often more dangerous pieces,” said Meijers.

There is no permanent human population in South Georgia, which the UK administers as a British overseas territory.

Argentina also claims the island, along with the Falklands to the west.

Icebergs of this size are rare, but not unheard of. There have been two of similar size in the same area in the last five years, said Meijers.

These huge icebergs are a “completely normal part of the life cycle” of the Antarctic ice sheets, Meijers emphasized.

But the ice shelves have lost 6,000 billion tons of mass since 2000, which is accompanied by accelerating ice loss attributed to climate change, he added.

Researchers warned last month that an increase in the planet's average temperature of between 1.5 and 2.0 degrees Celsius above pre-industrial levels could melt enough frozen water to raise the oceans by a dozen meters - and beyond the point of no return.

Last year, which broke previous heat records while the world was hit by fires, floods and storms, was the first calendar year above 1.5ºC.

dl/gil