Antarctica narrowly escapes collision with huge iceberg

With rising temperatures and significant climate changes predicted for Antarctica in the coming years, the ice continent could use a break. Now it’s getting one, as it has just nearly collided with a giant iceberg twice the size of Chicago.

The iceberg in question is the A-74. Originally attached to Antarctica, it broke out into open waters back in February, the result of a major crack that broke through the Brunt Ice Shelf in just a few months.

Then, for the past six months, the A-74 kept close to its original position, largely due to the ocean currents that prevailed in the area; but in early August, a strong easterly wind forced the iceberg to move south and twist, changing its course.

Along the way, it touched the edge of the Brunt Ice Shelf, where it was born, in what the European Space Agency (ESA) called a “minor collision.”

Had it been strong, another giant chunk might have broken off Brunt.

“A nosy chunk of the ice shelf, which is even larger than the A-74, remains connected to the Brunt Ice Shelf, but just barely,” said ESA geophysicist Mark Drinkwater.

“If the iceberg had collided with this piece with more force, it could have accelerated the collapse of the remaining ice bridge, causing it to break away. We will continue to monitor the situation regularly with Sentinel satellite imagery.”

These satellite images are crucial to finding out what’s happening to Antarctica on the largest scale: the integrated radar instruments are capable of imaging the remotest regions day and night, summer and winter, in all weather conditions.

At 1,270 square kilometers (490 square miles), the A-74 is one of the largest free-floating icebergs in the world (the largest is the A-76 iceberg, which came down earlier this year and covers 4,320 square kilometers).

If A-74 had actually crashed into the Brent Ice Shelf, a new iceberg of about 1,700 square kilometers (656 square miles) could have formed, according to ESA.

This is due to the presence of other cracks that have put the western edge of the Brant Ice Shelf in a dangerous position – Chasm 1, extending from the south, and the Hallowe’en crack to the north, running from west to east.

https://www.sciencealert.com/images/2021-08/iceberg-ani.gif

Meanwhile, shifting ice is keeping researchers busy: in 2017, the Halley VI research station was moved 20 kilometers (12.4 miles) to make it safer from an ice shelf landslide that scientists knew could happen.

“The Halley station consists of eight interconnected capsules mounted on skis, making it easy to move the capsules in the event of unstable ice or new chasms forming on the ice shelf,” ESA explained in a statement.

Late last year, another free-floating iceberg called A68a came dangerously close to South Georgia Island in the South Atlantic Ocean, home to millions of penguins, sea lions, albatrosses and petrels.

As the climate crisis continues to unfold around the world, scientists need all the information they can get about how Antarctic ecosystems might change in the coming years. In the meantime, the icebergs will continue to arrive.

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