Hexbyte Glen Cove Giant iceberg breaks off near UK Antarctic base thumbnail

Hexbyte Glen Cove Giant iceberg breaks off near UK Antarctic base

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A vast iceberg almost the size of Greater London has broken away from the Antarctic ice shelf near a British research station, the British Antarctic Survey said Friday.

The research body said the iceberg measuring 1,270 square kilometres (490 square miles) had broken off from the 150-metre-thick Brunt Ice Shelf in a process called “calving”.

This came almost a decade after scientists first saw massive cracks had formed in the shelf.

A crack in the ice widened by several hundred metres on Friday morning before the iceberg broke off completely.

Britain’s Halley VI Research Station monitors the state of the vast floating ice shelf daily.

“Our teams at BAS have been prepared for the calving of an iceberg from Brunt Ice Shelf for years,” said BAS director Jane Francis.

The mobile research base relocated inland for in 2016-2017 as cracks in the ice threatened to cut it off.

“That was a wise decision,” commented Simon Garrod, BAS director of operations.

The glaciologists said the latest event is unlikely to affect the station’s current location.

The base’s 12-person team left earlier this month, as they leave the base uninhabited in winter due to the unpredictable conditions.

While they are away, data from GPS instruments at the site goes to a centre in Cambridge, eastern England, for analysis.

Icebergs naturally break off from Antarctica into the ocean in a process accelerated by .

The BAS said in this case, there is “no evidence that climate change has played a significant role”.

“Over coming weeks or months, the may move away; or it could run aground and remain close to Brunt Ice Shelf,” said Francis.

The British Antarctic Survey is a world leader in environmental research in the region.

© 2021 AFP

Giant iceberg breaks off near UK Antarctic base (2021, February 26)
retrieved 1 March 2021
from https://phys.org/news/2021-02-giant-iceberg-uk-antarctic-base.html

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Hexbyte Glen Cove Massive iceberg threatens remote penguin sanctuary  thumbnail

Hexbyte Glen Cove Massive iceberg threatens remote penguin sanctuary 

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King penguins like these could see their foraging routes cut off by the giant iceberg

The world’s biggest iceberg is on a collision course with a remote South Atlantic island that is home to thousands of penguins and seals, and could impede their ability to gather food, scientists told AFP Wednesday.

Icebergs naturally break off from Antarctica into the ocean, but climate change has accelerated the process—in this case, with potentially devastating consequences for abundant wildlife in the British Overseas Territory of South Georgia.

Shaped like a closed hand with a pointing finger, the iceberg known as A68a split off in 2017 from Larsen Ice Shelf on the West Antarctic Peninsula, which has warmed faster than any other part of Earth’s southernmost continent.

At its current rate of travel, it will take the giant ice cube—which is several times the area of greater London—20 to 30 days to run aground into the island’s shallow waters.

A68a is 160 kilometres (93 miles) long and 48 kilometres (30 miles) across at its widest point, but the iceberg is less than 200 metres deep, which means it could park dangerously close to the island.

“We put the odds of collision at 50/50,” Andrew Fleming from the British Antarctic Survey told AFP.

Many thousands of King penguins—a species with a bright splash of yellow on their heads—live on the island, alongside Macaroni, Chinstrap and Gentoo penguins.

A68a iceberg, drifting in the South Atlantic, could crush organisms and their seafloor ecosystem, which would need decades or centuries to recover

Seals also populate South Georgia, as do wandering albatrosses, the largest bird species that can fly.

If the iceberg runs aground next to South Georgia, foraging routes could be blocked, hampering the ability of penguin parents to feed their young, and thus threatening the survival of seal pups and penguin chicks.

Release of stored carbon

“Global numbers of penguins and seals would drop by a large margin,” Geraint Tarling, also from the British Antarctic Survey, told AFP in an interview.

The incoming iceberg would also crush organisms and their seafloor ecosystem, which would need decades or centuries to recover.

Carbon stored by these organisms would be released into the ocean and atmosphere, adding to caused by , the researchers said.

As A68a drifted with currents across the South Atlantic, the iceberg did a great job of distributing microscopic edibles for the ocean’s tiniest creatures, said Tarling.

Icebergs naturally break off from Antarctica into the ocean, but climate change has accelerating the process

“Over hundreds of years, this has accumulated a lot of nutrients and dust, and they are starting to leach out and fertilise the oceans.”

Up to a kilometre thick, icebergs are the solid-ice extension of land-bound glaciers. They naturally break off from ice shelves as snow-laden glaciers push toward the sea.

But global warming has increased the frequency of this process, known as calving.

“The amount of ice going from the centre of the Antarctic continent out towards the edges is increasing in speed,” Tarling said.

Up to the end of the 20th century, the Larsen Ice Shelf had been stable for more than 10,000 years. In 1995, however, a huge chunk broke off, followed by another in 2002.

This was followed by the breakup of the nearby Wilkins Ice Shelf in 2008 and 2009, and A68a in 2017.

Hydrofracturing—when water seeps into cracks at the surface, splitting the ice farther down—was almost certainly the main culprit in each case.

© 2020 AFP

Massive iceberg threatens remote penguin sanctuary  (2020, November 4)
retrieved 7 November 2020
from https://phys.org/news/2020-11-massive-iceberg-threatens-remote-penguin.html

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