Friday, November 15

The London-sized chunk of ice that broke off Antarctica and why it's interesting to science

El pedazo de hielo del tamaño de Londres que se desprendió de la Antártida y por qué es interesante para la ciencia

Halley Station is known for its research on the ozone layer.

Photo: BAS / THOMAS BARNINGHAM / Courtesy

A large iceberg of about 1, 270 square kilometers, roughly the size of the London metropolitan area, broke off from Antarctica.

This Friday, detection instruments at the surface of the Brunt ice shelf confirmed the separation.

Not far away, the British Antarctic Survey (BAS), a UK institution dedicated to research from Antarctica, operates Halley Station. Since 2017 has done so with reduced capacity due to the impending prospect of a detachment .

Currently there is no one at the base, so there is no risk to human life.

BAS has a variety of GPS devices on the Brunt platform that transmit information about ice movements to the agency’s headquarters in Cambridge.

Experts will inspect the satellite images of what happened when they are available.

They will want to verify that unexpected instabilities do not appear in the remaining ice shelf where the Halley station is located.

“Although the rupture of large pieces of the Antarctic ice shelves is something completely normal from its operation, large landslides such as the one detected on the Brunt ice shelf on Friday continue being quite rare and exciting, “said Professor Adrian Luckman, who has been tracking satellite images of the Brunt for the past few weeks and predicted the breakout.

” With three long fissures that have been actively developing in the Brunt platform system for the last five years, we have all been anticipating that something spectacular was going to happen, “he told the BBC.

“Time will tell if this detachment will cause more pieces to break off in the coming days and weeks. At Swansea University we study the development of ice shelf cracks because while some lead to large landslides, others do not; and the reasons for this may explain why large ice shelves exist, “he added.

Borde del iceberg A68
Although the new iceberg is huge, it is not as big as the A 68 (in this image) which is four times the size of London.

Where exactly did the breakup occur?

The detachment detected this Friday is on the Brunt ice shelf, which is the floating bulge of glaciers that have flowed from the land into the Weddell Sea.

On a map, the Weddell Sea is that sector of Antarctica directly south of the Atlantic Ocean. The Brunt is on the eastern side of the sea.

As with all ice shelves, periodically icebergs break off from it. The last large chunk to break off in this area was at the beginning of the decade of 1970.

How big is the new iceberg?

Estimated to measure about square miles (1, 270 square kilometers). That’s big from any point of view, although not as big as Iceberg A 68 that came off in July 2017 of the Larsen C ice shelf, on the western side of the Weddell Sea.

But even with a quarter the size of A 68 It will be necessary to track this Brunt block due to the future risk it could represent for navigation.

The US National Ice Center will give the new detachment a name in due course. Since it is in the same Antarctic quadrant (0 – 90 W) from which the A originated 68, will also have the letter “A” in its name. It is likely called A 74

Is this a consequence of climate change?

Do not. The detachment of icebergs on the leading edge of an ice shelf is a very natural behavior.

The platform tends to balance and the expulsion of icebergs is a way of balancing the accumulation of masses derived from snowfall and the entry of more ice from glaciers that feed on land.

Unlike the Antarctic Peninsula, across the Weddell Sea, scientists have not detected climate changes in the Brunt region that would significantly alter the natural process described above.

In addition, estimates suggest that the Brunt had reached its greatest extension in recent 100 years when this detachment occurred. This rupture was long overdue.


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