World's largest iceberg may crash into a wildlife sanctuary

In the Southern Ocean, the world’s largest iceberg is making headlines with its colossal presence and potential impact on wildlife and humans alike.

The protagonist of this unfolding tale? A gargantuan iceberg named A23a, a marvel of nature that once stretched over 1,540 square miles – twice the size of Greater London. For perspective, the current size of the main section is roughly comparable to the entire county of Cornwall, UK.

However, it isn’t A23a’s size that’s now causing a sense of trepidation among scientists. It’s the iceberg’s trajectory that is now the primary concern.

A23a has become untethered from the South Orkney Islands and is ominously drifting towards South Georgia – a British territory and wildlife haven.

Stark warning from the high seas

Commanding the South Georgia government vessel, Pharos, Simon Wallace has observed the impending crisis first-hand.

“Icebergs are inherently dangerous. I would be extraordinarily happy if it just completely missed us,” he said.

Iceberg A23a isn’t just a looming mass of ice. It’s a potentially devastating force, with parts of it already breaking into large slabs.

These fragments could dwell in the surrounding waters for years, making nautical navigation a perilous undertaking.

From Antarctica to the Southern Ocean

The story of A23a began in 1986, when the iceberg was born from the Filchner Ice Shelf of Antarctica. It lay dormant at the seabed of the Weddell Sea before embarking on its journey north in 2020.

Initially, the iceberg’s progress was hindered by an ocean phenomenon known as a Taylor Column, causing it to spin almost on the spot.

Nonetheless, its liberty was confirmed by satellite images in December, which showed it had split from its restrictive shackles.

“It’s exciting to see A23a on the move again after periods of being stuck. We are interested to see if it will take the same route the other large icebergs that have calved off Antarctica have taken,” noted Dr Andrew Meijers, an oceanographer with the prestigious British Antarctic Survey (BAS).

Antarctica’s iceberg highway

Interestingly, NASA reports that most icebergs from Antarctica follow a similar route. Over 90% of them enter the Weddell Gyre’s clockwise-flowing current off East Antarctica.

They ultimately make their way north along the Antarctic Peninsula and venture into the Drake Passage’s warmer South Atlantic waters. This passage is playfully referred to as “iceberg alley.”

Iceberg threat to South Georgia

This isn’t the first time South Georgia has faced the prospect of an invading iceberg. In 2017, an iceberg named A68a embarked on a three-year, 10,000-mile odyssey towards the island, fortunately passing by without incident.

However, three years later, an iceberg called A76 posed a similar threat, leaving dangerous ice slabs scattered around the island.

“Those pieces basically cover the island – we have to work our way through it,” said Captain Wallace.

A wildlife sanctuary at risk

The island, located in the southern Atlantic Ocean, is often referred to as a “wildlife sanctuary.” It is a true oasis amid the tumultuous Southern Oceans.

From penguins and seals to whales and albatrosses, this sanctuary is home to a dazzling array of species.

The majestic A23a has now become a point of intense study for scientists, sailors, and fishermen as they closely monitor its movement via satellite images.

“The iceberg, at least in satellite images, appears to be maintaining its structure and has not yet broken up into smaller chunks, as previous “megabergs” have done,” noted Dr. Meijers.

“It is presently in a meander of the current and not moving directly towards the island, but our understanding of the currents suggests that it is likely to again move towards the island soon.”

Dr. Meijers noted that the current follows the shallow continental shelf around the island to the south east, but the question is whether the berg will follow this out into the open South Atlantic, or run up onto the shelf and become stuck for some time.

“If this happens it could seriously impede access to feeding grounds for the wildlife – seals and penguins mostly – that breed on the island.”

The story of A23a serves as a stark reminder that while mankind’s actions may contribute to climate change, nature itself is perfectly capable of scripting its own potentially perilous narratives.

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