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After slowly drifting round Antarctica for greater than a yr and barely melting, the world’s largest iceberg might quickly be set on an accelerated course towards its eventual demise, a brand new satellite tv for pc 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 facet of Antarctica’s Ronne Ice Shelf in Might 2021 and later fractured into three chunks: A-76A, A-76B and A-76C.
On Oct. 31, NASA’s Terra satellite tv for pc 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 reveals that the girthy berg is presently 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’s going to 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 shortly dragged eastward by robust ocean currents, earlier than being whipped northward into hotter waters, the place they utterly soften quickly after, in keeping with Earth Observatory.
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To this point, 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. Knowledge collected by the U.S. Nationwide Ice Middle in June revealed that A-76A is sort of precisely the identical dimension because it was when it fractured from its father or mother berg greater than a yr in the past, in keeping with Earth Observatory.
Nevertheless, 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 primary cause 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 another present on Earth. The ACC, which runs from west to east via the Drake Passage, transports between 3,400 and 5,300 million cubic ft (95 and 150 million cubic meters) of water each second, in keeping with 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.
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The ACC will not be 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 research within the journal Science Advances 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 highly effective ocean currents after narrowly avoiding a probably catastrophic collision with South Georgia Island in late 2020. On the time, researchers have been shocked when the mighty berg all of the sudden fractured in the course of the ocean. However the research revealed {that a} sudden shift within the path and power of close by currents was guilty for the large iceberg’s breakup.
It’s presently unclear how lengthy A-76A will stay within the Drake Passage, the place it is going to find yourself, and the way lengthy it is going to survive as soon as turbulent currents fling the ice mass northwards.
