World’s biggest iceberg breaks free and could leave Antarctic waters

An iceberg that’s twice the size of London and two thirds the height of the world’s tallest skyscraper has started drifting away from Antarctica and could wind up in British waters

The world’s biggest iceberg is on the move for the first time after being stuck to the ocean floor for 30 years.

The iceberg, called A23a, is 3884 km sq in size, which is twice the size of London.

It is also 399m thick, which is about two-thirds as high as the world’s tallest skyscraper, the Burj Khalifa in Dubai.

The iceberg split from the Antarctic coastline in 1986 but got stuck to the ocean floor and became an ice island.

It started drifting again in 2020 but picked up speed this year as wind and currents pushed it along faster.

The iceberg has started heading past the northern tip of the Antarctic Peninsula and could soon leave Antarctic waters altogether.

British Antarctic Survey remote sensing expert Dr Andrew Fleming told the BBC that scientists had been expecting the iceberg to start moving again once it had melted enough to lose its grip on the ocean floor.

The iceberg will most likely end up in the Antarctic “Circumpolar Current” before being pushed into a path known as “iceberg alley”.

Icebergs like A23a that end up in the Weddell sector usually follow the same path because of the movements of the Circumpolar Current, which is the strongest current in the Earth’s oceans.

From there, the huge iceberg might drift towards South Georgia island, which often has big tabular icebergs sitting off its coast.

The ice blocks usually get pinned on the shallow continental shelf of the island, which is considered British territory.

If A23a gets stuck near South Georgia, it might pose a problem for the millions of seals, penguins and other seabirds that live on the island.

The mega berg could get in the way of the animals’ normal foraging routes, stopping them from feeding their young properly.

But all icebergs eventually melt and wither away, releasing mineral dust.

And this dust is an important part of oceanic food chains.

“In many ways these icebergs are life-giving; they are the origin point for a lot of biological activity,” said Dr Catherine Walker, from the Woods Hole Oceanographic Institution.

The scientists will observe the movement of A23a closely.

GLOSSARY

• Circumpolar current: an ocean current that flows clockwise around Antarctica from west to east

• Weddell sector: part of the Weddell Sea, off the north of Antarctica

• tabular icebergs: icebergs with flat tops that have broken off an ice shelf or glacier

• continental shelf: the edge of the continent that is covered by water

• British territory: under British rule

• foraging routes: places to look for food

• oceanic: things that have something to do with the ocean

• origin point: starting point

• biological: related to life and living things

BASIC SHORT ANSWER 4

Fill in the blanks with NO MORE THAN 3 WORDS AND/OR A NUMBER

1. What is the size of the iceberg in comparison to that of London?

2. What has prevented the world's biggest iceberg from moving for 30 years?

3. What is the name of the iceberg?

4. Where is the world's tallest skyscraper?

5. What are the main causes of faster movement of the iceberge this year?

6. What is the strongest current in the Earth’s oceans?

7. What can people usually find around South Georgia island?

8. What kinds of animal might be in danger if A23a gets stuck near South Georgia island beside seals and penguins?

9. What will icebergs leave after melting?

10. Icebergs are the foundation of plenty of ...