World’s largest iceberg breaks free

The giant hunk of ice, three times the size of NYC, is on the move for the first time in decades

An iceberg roughly equivalent to three times the area of New York City has broken free from the ocean floor and has begun drifting north towards the so-called ‘Iceberg alley,’ scientists have reported.

The iceberg, called A23a, is the largest in the world at a colossal 1,500 square miles (4,000 square km). It broke away from the Antarctic coast in 1986 but soon grounded itself in the Weddell Sea, effectively transforming the area into a giant ice island.

After remaining in situ for some 37 years, however, scientists confirmed on Friday that satellite imagery has shown the trillion-ton hunk of ice drifting north past the Antarctic Peninsula, backed by strong winds and ocean currents.

An iceberg of this size on the move is a rare sight for glaciologists. “Over time it’s probably just thinned slightly and got that little bit of extra buoyancy that’s allowed it to lift off the ocean floor and get pushed by ocean currents,” Oliver Marsh of the British Antarctic Survey said, according to Reuters.

Why exactly the ‘berg, which is the oldest such slab of ice on the planet, has shaken free of its moorings remains a mystery, for now at least. “The consensus is the time had just come,” Dr Andrew Fleming, a colleague of Marsh’s, told the BBC.

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“It was grounded since 1986 but eventually it was going to decrease (in size) sufficiently to lose grip and start moving,” said Fleming, adding that he had noted telltale signs of the impending journey back in 2020.

Like most icebergs in the region, A23a will very likely maneuver into the Antarctic Circumpolar Current which in turn will deliver it towards ‘iceberg alley,’ where several of its peers congregate in the dark waters.

Scientists fear, though, that the giant iceberg could once again ground itself off South Georgia Island in the South Atlantic, potentially wreaking havoc for Antarctic wildlife by cutting access to millions of seals, penguins and seabirds who use the area to breed or to hunt for food.

Like all icebergs, A23a’s ultimate fate will see it melt away into nothingness – but a behemoth like this one could take a long time to do so, potentially causing more headaches down the line.

“An iceberg of this scale has the potential to survive for quite a long time in the Southern Ocean even though it’s much warmer,” Marsh told Reuters. “It could make it way farther north up towards South Africa, where it could disrupt shipping.”