Explained: Why is a giant Antarctic iceberg ‘A68a’ a cause for concern?

The giant iceberg A68, the biggest block of free-floating ice from Antarctica with an area of about 5,800 sq. km, has been drifting in the Atlantic Ocean since 2017. This year, due to an ocean current, the iceberg was propelled into the South Atlantic Ocean and since then it has been drifting towards the remote sub-Antarctic island of South Georgia, prompting fears about the impact the iceberg could have on the island’s abundant wildlife.

Icebergs travel with ocean currents and either get caught up in shallow waters or ground themselves.

What is the giant iceberg A68a and where is it headed?

A68a, an iceberg roughly the size of the state of Delaware, split off from Antarctica’s Larsen C ice shelf in July 2017. Since then it has been drifting towards the remote island of South Georgia, which is a British Overseas Territory (BOT).

On its journey, smaller icebergs have calved from the iceberg and right now, the biggest section of the iceberg is called A68a and spans an area of roughly 2,600 sq. km. Last week, the US National Ice Center (USNIC) (USNIC is responsible for naming icebergs, which are named according to the Antarctic quadrant in which they are spotted) confirmed that two new icebergs calved from A68a and were large enough to be named and tracked. They are called A68E and A68F.

The fear is that if the iceberg grounds itself near the island, it could cause disruption to the local wildlife that forages in the ocean. As per ecologists from the British Antarctic Survey (BAS), which will launch a research mission to study A68a’s impact on the ecosystem next month, if the iceberg gets stuck near the island, it could mean that penguins and seals will have to travel farther in search of food, and for some this might mean that they don’t get back in time to prevent their offspring from starving to death.

In this recent handout photo provided by the Ministry of Defense on Wednesday, Dec. 23, 2020, fragments fall from the A68d iceberg that had broken off from the northern part of its parent berg the A68a and is now roughly 30 nautical miles away from South Georgia in the South Atlantic. (AP)

On the other hand, there are some positives of an iceberg being stuck in the open ocean, since icebergs carry dust which fertilises ocean plankton, which draws up carbon dioxide from the atmosphere.

Why did the iceberg calve?

As per BAS, the iceberg’s calving is thought to be a natural event and not a result of climate change. However, some models predict that a warming Antarctica in the future could mean more calving events as ice shelves and glaciers retreat.