After slowly drifting round Antarctica (opens in new tab) for greater than a yr and barely melting, the world’s largest iceberg may quickly be set on an accelerated course towards its eventual demise, a brand new satellite picture reveals.
The gargantuan ice slab, often known as A-76A, is round 84 miles (135 kilometers) lengthy and 16 miles (26 km) large. It’s the largest fragment of the world’s earlier greatest iceberg, the Rhode Island-size A-76, which broke off from the western side of Antarctica’s Ronne Ice Shelf (opens in new tab) in Could 2021 and later fractured into three chunks: A-76A, A-76B and A-76C.
On Oct. 31, NASA’s Terra satellite captured a photograph of A-76A floating within the mouth of the Drake Passage, a deep waterway that connects the Pacific and Atlantic oceans between Cape Horn in South Africa and the South Shetland Islands to the north of the Antarctic Peninsula. The picture exhibits that the girthy berg is at the moment sitting between Elephant Island and the South Orkney Islands (each obscured by clouds within the picture) on the southern finish of the passage, however its trajectory hints that it’ll head additional north into the waterway within the coming weeks. The picture was launched on-line Nov. 4 by NASA’s Earth Observatory (opens in new tab).
Usually, when icebergs drift into the Drake Passage they’re rapidly dragged eastward by sturdy ocean currents, earlier than being whipped northward into hotter waters, the place they fully soften quickly after, based on Earth Observatory.
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Thus far, A-76A has traveled round 1,250 miles (2,000 km) since breaking off from the Antarctic Peninsula in 2021. The berg has managed to keep away from substantial ice loss throughout its journey up to now. Information collected by the U.S. Nationwide Ice Middle in June revealed that A-76A is sort of precisely the identical measurement because it was when it fractured from its mother or father berg greater than a yr in the past, based on Earth Observatory.
Nonetheless, it’s unlikely to stay intact for much longer as a result of the Drake Passage is famend for sending icebergs on a one-way journey to their watery graves. The principle purpose for that is the Antarctic Circumpolar Present (ACC); it is the one present that flows solely across the globe, and it incorporates extra water than some other present on Earth. The ACC, which runs from west to east by way of the Drake Passage, transports between 3,400 and 5,300 million cubic toes (95 and 150 million cubic meters) of water each second, based on Britannica (opens in new tab). Because of this, wandering bergs that enter the Drake Passage are swiftly dragged away from the Antarctic and dumped in hotter waters, the place they quickly soften away.
The ACC is just not the one ocean present that helps decide the destiny of icebergs. Different smaller currents additionally play a key position within the distribution and eventual destruction of the wandering ice lots, however researchers are nonetheless attempting to grasp precisely how.
On Oct. 19, a examine within the journal Science Advances (opens in new tab) revealed that one other record-breaking berg, A68a, which held the title of the world’s largest iceberg for round three years, was ripped in half by powerful ocean currents (opens in new tab) after narrowly avoiding a potentially catastrophic collision (opens in new tab) with South Georgia Island in late 2020. On the time, researchers had been shocked when the mighty berg out of the blue fractured in the midst of the ocean. However the examine revealed {that a} sudden shift within the course and power of close by currents was in charge for the large iceberg’s breakup.
It’s at the moment unclear how lengthy A-76A will stay within the Drake Passage, the place it should find yourself, and the way lengthy it should survive as soon as turbulent currents fling the ice mass northwards.
