World’s Largest Free-Floating Iceberg Is Starting to Crack Up

Iceberg A68a, along with new fragments, as spotted by the Sentinel-1 satellite on December 22nd, 2020 21:33 UTC.
Iceberg A68a, along with new fragments, as spotted by the Sentinel-1 satellite on December 22nd, 2020 21:33 UTC.
Image: Copernicus Sentinel/Sentinel Hub/Pierre Markuse

After more than three years of drifting through the Southern Ocean and taking a run at an biodiverse island, iceberg A68 is beginning to fall apart. The latest satellite imagery shows massive cracks forming along the surface of the biggest iceberg on Earth in what could be a sign of the iceberg finally losing its cohesion.

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Images taken by the European Sentinel-1 satellite on Tuesday show large cracks forming on the southern portions of the ‘berg, along with two new discrete icebergs. A68a— which calved from Antarctica’s Larsen C Ice Shelf in July 2017—is currently floating in the southern fringe of the Atlantic Ocean in the vicinity of South Georgia island. The 1,500-square-mile (3,884-square-kilometer) iceberg had been drifting towards the ecologically sensitive island, raising concerns over the past month that it could get stuck along the shallow seafloor and disrupt the local wildlife.

In a sign of things to come, the iceberg lost a sizable chunk late last week70-square-mile (181-square-kilometer) iceberg now named A68d (iceberg A68a lost a couple of pieces, A68b and A68c, earlier during its long journey).

The reason for the fragmentation is likely on account of strong ocean currents and other instabilities in the region. The iceberg has rotated dramatically over the past several days, resulting in a shearing effect.

Prompted by the latest satellite imagery, the U.S. National Ice Center has identified and named two more icebergs, now named A68e and A68f. The larger piece, A68e, measures 38 miles (61.2 kilometers) long and 9 miles (14.8 kilometers) wide, while the smaller piece, A68f, measures 16 miles (25.8 kilometers) long and 8 miles (12.9 kilometers) wide. The National Ice Center names icebergs based on the Antarctic quadrant from which they were originally sighted, and the sequential order in which they appeared.

Marked-up view of the new fragments, including A68d, which calved late last week.
Marked-up view of the new fragments, including A68d, which calved late last week.
Image: Copernicus Sentinel/Sentinel Hub/Pierre Markuse

Iceberg A68a may be fragmenting, but South Georgia island is not yet out of the woods. Scientists will be keeping a close watch on the iceberg and its brood over the coming days and weeks, as it and its new baby ‘bergs float around the island. Some large pieces could still get stuck on the seafloor, disrupting local wildlife such as penguins and seals.

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But this is the way of icebergs. Gigantic masses like A68a don’t just melt away into oblivion. Rather, they fragment into increasingly smaller pieces over time, and it’s these smaller pieces that gradually melt over time. A68a may be dying, but its many offspring will continue to live on, likely for many years to come.

Senior staff reporter at Gizmodo specializing in astronomy, space exploration, SETI, archaeology, bioethics, animal intelligence, human enhancement, and risks posed by AI and other advanced tech.

DISCUSSION

dnapl
Dense non aqueous phase liquid

Towability may be better now. There was a dude who wanted to tow icebergs up to South Africa from Antarctica. That was in the news last year.

Let’s assume A-68E is the one to tow. Let’s also assume it’s not lodged onto the sea floor and thusly towable. Length and width dimensions from above. Depth of 75 meters pulled off the internet. Could be less, but let’s move on.

A-68E: 61,000 meters x 15,000 meters x 75 meters = around 69 billion cubic meters or 69 trillion liters.

According to world-o-meter, South Africa consumes about 16 billion cubic meters (or 16 trillion liters) of water per year. So at least a year of water, maybe more.

How fast an iceberg melts as it’s towed into warmer water and what to do with an iceberg sitting off the coast is probably something to noodle on.

Please note: comment section math is around 50/50 right/wrong. Comment section water sourcing feasibility analysis is at best a crap shoot.