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A huge Antarctic iceberg the size of a small country is heading for the island of South Georgia with concerns that it could disrupt the British Territory’s economy and wildlife.
The A-68A iceberg broke off the Larsen C Ice Shelf in the eastern Antarctic Peninsula in July 2017 and is about the same size as South Georgia, where it is feared it may head.
The A-68A, which is now 150 km (93 miles) long and 48 km (30 miles) wide, has veered about 1,400 km north through an area known as “icebergs alley” to meet about 500 km from South Georgia.
“It’s absolutely huge and it’s the largest iceberg in the Southern Ocean,” said Dr Sue Cook, a glaciologist with the Australian Antarctic Program Association.
She told The Guardian that the iceberg was following a familiar trail to many others, but its final destination was very difficult to predict. “It has lasted three years, which is longer than expected,” he said.
Cook said weather patterns, currents and the shape of the iceberg make predictions difficult. The gigantic island of floating ice, which is only about 200 meters thick, could break or run aground.
The iceberg’s thin profile, which has been monitored by satellites, may make it more likely to float closer to South Georgia before getting stuck on the ocean floor.
Professor Geraint Tarling of the British Antarctic Survey told the BBC that he was concerned about the iceberg’s potential to impact South Georgia.
“A nearby iceberg has massive implications for where land predators might feed,” he said.
“When you talk about penguins and seals during the period that is really crucial for them, during the rearing of cubs and chicks, the actual distance they have to travel to find food really matters. If they have to make a big detour, it means they won’t get back to their young in time to prevent them from starving in the meantime. “
Tarling said that while ecosystems are recovering, there is a risk that the iceberg will remain for a decade. “That would make a huge difference, not just to the South Georgia ecosystem, but to its economy as well,” he said.
The chunk broke off Antarctica’s Larsen C Ice Shelf in July 2017 and, at the time, was about 175 km long and about 50 km wide, larger than Luxembourg.
According to the European Space Agency, the iceberg lost an early chunk, prompting a naming convention in which the largest section was renamed A-68 to A-68A and the smaller piece A-68B.
A-68A lost another piece in April 2020 (spawning A-68C) and is now about 150 km long and 48 km wide. South Georgia is 165 km long and 35 km wide.
In April, the iceberg was 230 kilometers west-southwest of the South Orkney Islands.
“It’s difficult for us to predict exactly where it will end up,” Cook said.
“It is about 500 km from South Georgia right now, but since it is 150 km long, it is not very far and I can see why people would be concerned. Since most of it is underwater, it will project a lot below, which means it’s easy for it to run aground, and that’s common too. “
He agreed that depending on where the iceberg ended up, it could disrupt the routes the animals used to reach the feeding grounds.
“It scrapes the seabed and affects those animal communities there. If one gets stuck in the wrong place, it can affect shipping. “
Cook said the iceberg release was natural and there was nothing about A-68A’s size that was particularly unusual “but this is happening in a region where there is a lot of change.”
The northern ice shelves had undergone disintegration events and it was speculated that Larsen C was also vulnerable to disintegration. “When a large area is lost, there is always the possibility that the remaining shelf is more unstable,” he said.
Dr Andrew Fleming, also from the British Antarctic Survey, told the BBC that the A-68A could also circle around South Georgia and head into warmer waters, where it could break apart much faster.
Ice shelves are already floating in the ocean, so when they break they don’t directly lead to a rise in ocean level.
