NewsBite

Advertisement

World’s largest iceberg on collision course with British island

By Samuel Montgomery

The world’s largest and oldest iceberg is on a collision course with a British island in the South Atlantic, raising fears that colonies of penguins and seals could be wiped out.

The mega-iceberg, known as A23a, is larger than the ACT and twice the size of Greater London. It broke off the Filchner Ice Shelf in Antarctica in 1986 before running aground for 30 years.

The iceberg, known as A23a, in November off the coast of Antarctica.

The iceberg, known as A23a, in November off the coast of Antarctica. Credit: AP

It became dislodged from the seafloor in 2020 and began drifting northwards until it was trapped in a swirling ocean vortex in 2024. It has now been slingshotted in the direction of the British overseas territory of South Georgia near South America.

It was about 278 kilometres from the island and was expected to make contact in two to four weeks, depending on ocean currents.

“Icebergs are inherently dangerous. I would be extraordinarily happy if it just completely missed us,” sea captain Simon Wallace told the BBC, speaking from the South Georgia government vessel Pharos.

“We have searchlights on all night to try to see ice; it can come from nowhere.”

In the past, penguin chicks and seal pups on South Georgia have died after giant icebergs blocked access to their feeding grounds.

The iceberg’s 400-metre cliffs are higher than the Gold Coast’s Q1 Tower – Australia’s tallest building – and it covers roughly 3500 square kilometres, though the warmer northern waters are melting the iceberg and could break it up.

Advertisement

Should it disintegrate, the segments could float around South Georgia uncontrollably for years, putting the territory’s king penguins, as well as elephant and fur seals, in danger.

In 2004, an iceberg called A38 grounded on the continental shelf to the north-east of South Georgia, devastating the penguin and seal populations by preventing them from using their foraging routes.

“South Georgia sits in ‘iceberg alley’, so impacts are to be expected for both fisheries and wildlife, and both have a great capacity to adapt,” Mark Belchier, a marine ecologist who advises the South Georgia government, told the BBC.

A team with the British Antarctic Survey aboard the Sir David Attenborough research vessel investigated A23a in 2023, sailing into a crack and collecting water samples.

Dr Andrew Meijers, chief scientist on the vessel, said: “It is amazing to see this huge berg in person – it stretches as far as the eye can see.”

An iceberg seen on NASA’s Aqua satellite, known as A23a, centre, is visible as it heads towards South Georgia Island.

An iceberg seen on NASA’s Aqua satellite, known as A23a, centre, is visible as it heads towards South Georgia Island.Credit: AP

Laura Taylor, a biogeochemist who also took part in the mission, said in December 2024: “We know that these giant icebergs can provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less-productive areas.”

She added: “We took samples of ocean surface waters behind, immediately adjacent to and ahead of the iceberg’s route. They should help us determine what life could form around A23a.”

The Telegraph, London

Get a note directly from our foreign correspondents on what’s making headlines around the world. Sign up for the weekly What in the World newsletter here.

Most Viewed in World

Loading

Original URL: https://www.smh.com.au/world/south-america/worlds-largest-iceberg-on-collision-course-with-british-island-20250124-p5l6va.html