Biggest iceberg in the world stalled, saving wildlife haven

PARIS – The largest iceberg on Earth appears to be grounded about 70 kilometers (about 44 miles) from a remote island in Antarctica, a development that could spare a critical wildlife haven from a direct hit, a research organization said Tuesday.

The enormous iceberg A23a — more than twice the size of Greater London and almost one trillion tonnes heavy — has been drifting away from the Antarctic towards South Georgia island.

That had heightened fears that it could crash into the island or run aground on shallower water around it, possibly interfering with the ability of penguins and seals to feed their young.

But the gigantic wall of ice has been hanging up 73 kilometres away from the island since March 1, British Antarctic Survey (BAS) said in a statement.

“If the iceberg remains grounded, we don’t expect it to dramatically impact the local wildlife,” said Andrew Meijers, an oceanographer at BAS.

“In the last few decades, the majority of icebergs that have taken this journey through the Southern Ocean quickly break up, disperse and melt,” said Meijers, who observed A23a in late 2023, and subsequently has tracked its fate using satellites.

Satellite photos analysed by AFP indicated the nearest end of the iceberg had been more than 70 kilometres from the island in late February.

It’s still unclear if the iceberg is stuck for good.

“It will be interesting to see what will happen now,” Meijers said.

Potential benefits for wildlife?

The world’s largest and oldest iceberg broke away from the Antarctic shelf in 1986.

For more than 30 years, it did not move much before being liberated in 2020, its slow trek north sometimes held back by ocean currents that kept it from making forward progress.

Satellite imagery had previously indicated that it was not disintegrating into smaller pieces along the well-known path taken by such icebergs. But in January a 19km section detached.

There were fears for wildlife on the key breeding grounds of South Georgia if the iceberg parked too close.

This would have compelled animals such as penguins and seals to journey much farther to navigate around the massive iceberg.

“This could reduce the food going back to pups and chicks on the island, and so increase mortality,” Meijers said.

But in its present location, the iceberg could have advantages for wildlife.

“Nutrients churned up by the grounding (of the berg) and from it melting may help the entire regional food web, including by raising food availability for such charismatic species as penguins and seals, Meijers said.

The seal and penguin populations on South Georgia were already suffering from a “bad season” because of a bird flu outbreak, Meijers told AFP in January.

What about climate change?

The iceberg does not pose a shipping threat. So big, in fact, that vessels can simply steer around it.

But as it fragments into smaller pieces, some areas might become off-limits to commercial fishing vessels “because of the quantity of smaller — although often more dangerous — bergy bits,” Meijers said.

The UK administers South Georgia as a British overseas territory, which has no permanent human population.

Argentina lays claim to the island as well — and the Falklands to the west.

Icebergs of this size are unusual, but not unprecedented. In the past five years, two of similar size have occurred in the same area, Meijers said.

The formation of such massive icebergs is a “perfectly normal part of the life cycle” of Antarctic ice sheets, Meijers stressed.

But ice shelves lost 6,000 billion tonnes of mass since the year 2000, matched by increasing ice loss, not least because of climate change, he said.

Last month, scientists cautioned that an increase in the planet’s average temperature to between 1.5 and 2.0 degrees Celsius above pre-industrial levels could thaw enough frozen water to raise oceans by a dozen metres — and past the point of no return.

Last year, which set multiple previous heat records as the planet was pummeled by fires, floods and storms, was also the first calendar year to average more than 1.5C of warming.