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Earth Science

World's Biggest Iceberg on the Move After 30 Years (bbc.com) 35

Posted by msmash from the watch-out dept.
The world's biggest iceberg is on the move after more than 30 years being stuck to the ocean floor. From a report: The iceberg, called A23a, split from the Antarctic coastline in 1986. But it swiftly grounded in the Weddell Sea, becoming, essentially, an ice island. At almost 4,000 sq km (1,500 sq miles) in area, it's more than twice the size of Greater London. The past year has seen it drifting at speed, and the berg is now about to spill beyond Antarctic waters. A23a is a true colossus, and it's not just its width that impresses.

This slab of ice is some 400m (1,312 ft) thick. For comparison, the London Shard, the tallest skyscraper in Europe, is a mere 310m tall. At the time, it was hosting a Soviet research station, which just illustrates how long ago its calving occurred. Moscow despatched an expedition to remove equipment from the Druzhnaya 1 base, fearing it would be lost. But the tabular berg didn't move far from the coast before its deep keel anchored it rigidly to the Weddell's bottom-muds.

So, why, after almost 40 years, is A23a on the move now? "I asked a couple of colleagues about this, wondering if there was any possible change in shelf water temperatures that might have provoked it, but the consensus is the time had just come," said Dr Andrew Fleming, a remote sensing expert from the British Antarctic Survey. "It was grounded since 1986 but eventually it was going to decrease (in size) sufficiently to lose grip and start moving. I spotted first movement back in 2020." A23a has put on a spurt in recent months, driven by winds and currents, and is now passing the northern tip of the Antarctic Peninsula.
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World's Biggest Iceberg on the Move After 30 Years More

World's Biggest Iceberg on the Move After 30 Years

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  • In the area left behind after the calving?
    • This ice shelf is (was) glacial ice that came from up in the mountains somewhere, met the coast, then spread out to form a thick (though a half or a quarter of the ice thickness, when it was a glacier confined in a valley) slab floating on the sea at it's edge but "grounded" on the seabed closer to the glacier's mouth. (Sometimes several adjacent glaciers in the coastal mountains merge together when they're spreading out along the coast.) By a combination of flexing under tides, and seawater currents driven

  • Units (Score:4, Funny)

    by crunchygranola ( 1954152 ) on Friday November 24, 2023 @01:32PM (#64029209)

    it's more than twice the size of Greater London.

    What is that in standard Manhattans?

  • For anyone who wants to pull it to their coast. And it can last for decades.

    • Re:Free freshwater (Score:5, Funny)

      by taustin ( 171655 ) on Friday November 24, 2023 @01:55PM (#64029251) Homepage Journal

      Most of the countries who would benefit from that would find it easier tow their country to the iceberg.

    • I was wondering about that. Could it be towed to Saudi Arabia before it all melted? Would it be more effective to put the diesel fuel to use in desalination instead?

    • "Free" for values of "free" similar to the "free" in "free diesel", and "free rental of multiple very powerful tugboats, which drink diesel like it's going out of fashion".

      You'd probably also need a lot of "free" plastic sheeting to reduce losses to melting en route (by reducing water flow near the ice surface underwater) and to reduce the amount of bird shit which you'd have to process out of the "fresh water". Well, for drinking - it'd be OK for agricultural water. Those thousands of square km of sheetin

  • How many rugby fields is that?

    • They measure the height in London Shards and the area in Greater Londons - how much more English do you want the units to be? Although I'll admit that referring to it as "Greater" London does sound rather inappropriate now.
    • What about cricket fields or soccer pitches? Those might be a more "international" units of measure.
  • That's a lot of salad

  • "the time had just come."

    - Shit happens
    - Was bound to happen sooner or later
    - Better late than never

    Love the answer. Somebody's trying to corner them into a statement about climate change. Shoulders are shrugged, and the question is poo-poo'd.

    This is the way I feel about the whole climate question. Shit's going down, we'll deal. Don't care about causality anymore.

    • It was already detached from the ice sheet. Eventually enough was going to melt to get it unstuck from the bottom. Then off it goes by way of wind and current.

  • Great, plant hundreds of autonomous motorized sails across its surface and set course for the worst drought-stricken coastline.

  • "Captain! There's a giant boat in our path!"
    "Ram it. Our Iceberg is invincible."

    (Thank you, Zach, for the laughter! "Hubris" [smbc-comics.com])

  • If someone could just lift it up and place it in the middle of the Saharas, that would be awesome.

    • How ... would a sudden, brief, inundation of the middle Sahara help to develop usable soils in an area of structureless loose rock ("reg" desert) or structureless loose sand ("erg" desert).

      Sorry, but soil science is a lot more complex than the people who created the "Dust Bowl" understood.

  • Well, by "normal", I mean normal for the Weddel Sea. Which is a pretty uncomfortable place for humans.

    Different masses of ice in the sea drift at different rates at various times, in a manner that is difficult to predict with our current level of knowledge. This is not new. The book about the voyage of the crew of Endurance, goes into a fair amount of detail about this, from the perspective of people who were trapped on the ice for a year or so (until they eventually found a way off) because nobody knew

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