The iceberg that became the star of social media melts


Wide but very thin: A68 averaged about 230m thick

The iceberg that was once the largest in the world is no longer there.

As is known, the A68 covered an area of ​​approximately 6,000 square kilometers (2,300 square miles) when separated from Antarctica in 2017.

It’s like a small country. It is one-fourth the size of Wales.

However, satellites show that Megaberg is virtually gone and divided into innumerable small pieces. US National Ice Center It’s no longer worth tracking.

A68 born from the Larson C ice shelf Located on the edge of the Antarctic Peninsula, it has hardly moved for a year. However, after that, riding the strong current and wind, it began to drift north while increasing its speed.

The one billion ton block followed a familiar route and spun out into the South Atlantic towards South Georgia’s British Overseas Territories. Small islands are where many of the largest icebergs die. It is destined to be caught in the local shallow water and gradually melt.

But this somehow managed to escape that particular fate.

Instead, it was the Atlantic waves, warm water, and higher temperatures that ultimately consumed the A68. It simply shattered into pieces.

“It’s amazing that the A68 lasted a long time.” Adrian Luckman of Swansea University, Told BBC News.

“Given the thickness ratio, it’s like stacking four sheets of A4 paper, so it’s very flexible and fragile as you move around the ocean. That’s how it lasted for years. But in the end it broke. When I split it into 4-5 pieces, they were also split. “



An iceberg born in the satellite era

The A68 is probably best remembered as the first iceberg to become a star on social media.

People around the world shared satellite photos online, especially when frozen blocks approached South Georgia. If it had been grounded, Berg’s immense size could have disrupted the foraging behavior of many penguins on the island-and who is worried about the penguins at risk?

Daily conversations on Twitter, Instagram, and more are made possible by today’s easy access to a range of publicly available space data tools.

“The A68 has attracted the attention of many different people,” commented mapping specialist Laura Gerish. British Antarctic Survey (BAS).. “We saw twists and turns little by little. We were able to track its progress with daily satellite imagery at a level of detail that we couldn’t really do before.”

Satellite image of the iceberg

The largest fragment, the A68a, looked like a hand with the index finger extended.

What did you learn from A68?

Of course, the iceberg wasn’t just a mystery. It was also the subject of some serious scientific research.

Its origin, the Larsen Ice Shelf, is a giant ice floating platform built by the fusion of glacier tongues that have slipped from land to sea.

The A68 life story almost certainly tells researchers how ice shelves are constructed and how they break down to form icebergs.

“One of the scientific consequences that is probably worth mentioning was how much we learned about the fracture toughness of suture zones where inland glaciers join to form floating ice shelves,” said the University of Maryland. Christopher Schumann of Baltimore County commented. (UMBC) and Nasa-Goddard.

“I’m confident that we’ve gathered useful insights that we couldn’t’see’10 years ago, as we had new sensors that looked at the evolution of the lift more often. This is a true testament to our investment in earth observation. “

Larsen ice shelf

The Larsen Ice Shelf is made up of glacier ice amalgam that has flowed from land to the sea.

Most glaciologists consider the A68 to be the product of a very natural process. Ice shelves maintain equilibrium, and Berg release is one way to balance mass buildup from snowfall with more ice influx from terrestrial feeding glaciers.

Therefore, in that sense, the A68 cannot be presented as a poster child of human-induced climate change.

However, A68 has shown a process in which warming destroys the structure of ice.

How ice turns into muddy very quickly


Hydrofracturing: A large area at the bottom of this iceberg debris collapses suddenly

One of these is called hydrofracturing. In this process, warming produces large amounts of surface meltwater that fills cracks and cracks and pushes these openings to the bottom of the ice.

Towards the end of A68’s existence, there were some great examples of hydrofracturing crushing the remaining debris almost overnight.

“‘Death by Hydrofracture’,’Slash’s Puppy’,” Ted Scanbos called. “Another example of the fast-forward evolution of icebergs, which shows how ice shelves collapse in a warmer world. I think icebergs have tested a lot of possible knowledge, and that knowledge has almost taken on the challenge.” CIRES-University of Colorado Boulder expert told BBC News.

Underwater robot sent for investigation

Robot glider and RRS James Cook

BAS placed the robot glider underwater and studied the environment around Berg

BAS also deployed two robots in the ocean in February in an attempt to scrutinize some of the late-day segments of the A68.

One soon went missing, and the other managed to release himself and continue observing after actually getting stuck in the ice for two weeks.

This robot will be restored in May and will acquire data. Information about how icebergs affect their surroundings, such as dumping large amounts of freshwater into the ocean as the iceberg melts, needs to be revealed.

How to end last week


The last major fragment known as A68a, seen at the end of an ice slash

USNIC is an internationally recognized agency for naming icebergs and tracking icebergs that can threaten shipping.

To be included in USNIC’s concerns, Berg’s major axis must be greater than 10 nautical miles (18.5 km) or more than 20 nautical miles (68.5 square kilometers) in area.

Currently, none of the A68 fragments are eligible. The last major part, known as the A68a, was measured on Friday to be only 3 nautical miles x 2 nautical miles. RIP.