South Georgia and the Other Iceberg of Doom

It’s déjà vu all over again

A couple of months ago I wrote a bit about iceberg A68 as what I called a “miniature of alarm.” To recap: iceberg A68 snapped off Larsen C in 2017 and slowly drifted north. By 2020 it was drifting towards South Georgia, which spawned stories like:

A68 iceberg heads towards South Georgia

An iceberg is heading towards the sub-Antarctic island of South Georgia. A68a – the size of the UK county of Somerset – broke off from the Larsen C ice shelf in 2017 and has been drifting north ever since. If it becomes grounded near the island, it could cause disruption to the local wildlife that forage in the food-rich ocean. Professor Geraint Tarling, an ecologist at British Antarctic Survey, says: “Ecosystems can and will bounce back of course, but there’s a danger here that if this iceberg gets stuck, it could be there for 10 years. An iceberg has massive implications for where land-based predators might be able to forage.”

BAS 4 November 2020

In reply to which I wrote:

The idea that A68 might end up stuck on South Georgia for ten years was very far fetched. In these pages I made the point … that South Georgia is at an equivalent latitude to Whitby. I did not make any comparisons between the life forms seen on the respective beaches of the two locations.

In comments under that post Dennis Ambler left this somewhat cryptic quote from a BAS press release, which I reproduce in its entirety:

Today 13 October 1998 the British Antarctic Survey received a satellite image showing an iceberg, approximately 150 km x 35 km, has broken off Ronne Ice Shelf, in the Weddell Sea, Antarctica (approx 77 S 50 W). In this region the front of the ice has now retreated to its 1947 position. The Ronne iceberg is four times the size of the last large iceberg to calve in the region which came from Larsen Ice Shelf. Dr Doake said “Regular calving of large ice bergs is a natural part of the life-cycle of an ice shelf. We have been expecting this event for some time…. Although ice shelves are retreating on the Antarctic Peninsula as a result of regional warming, we do not believe that this event is associated with climate change.”

The date was 19 years before A68 broke free and 22 before it became the iceberg of doom.

What Dennis had remembered but I had not was what became of the earlier iceberg of doom, A38. It took five years for A38 to drift north and reach the position A68 had when all the alarm bells started ringing in 2020. And what it was later feared A68 would do A38 actually did. On Christmas Day 2003, A38 grounded in the shallows by South Georgia:

South Georgia, December 25, 2003: NASA Worldview

Here are a couple of snaps from space showing what happened next.

South Georgia, April 17, 2004: NASA Worldview

South Georgia, October 14, 2004: NASA Worldview

A38 survived for the southern winter, but in all hung about for less than ten months. Not ten years: ten months. As to its impact on wildlife, I’m not sure. Wiki says this:

Iceberg A-38B remained grounded for some months, affecting the foraging routes of adult seals and penguins, resulting in the death of young penguins and seals on the beaches of South Georgia.[7]

Wiki

The link [7] takes you to the BBC, in a story about the panic around A68, wherein it is written:

When the colossus A38 grounded at South Georgia in 2004, countless dead penguin chicks and seal pups were found on local beaches.

It would take a more dedicated search to find actual data on such matters, if there are any. To judge by the fact that the link used at Wiki was to a BBC story published 16 years later, perhaps there are no such data.

The point of all this is that a recent analogue of A68 (A38 was in fact larger when it broke free: 2750 square miles vs 2200) actually did what it was feared A68 would do. It grounded in the shallows at South Georgia. But it did not get stuck for a decade: it got stuck for one winter, less than ten months in all. Now, it is excusable for an amateur like YT to be unaware of this or to have forgotten it. Not so a professional, who should have known very well the history, if prepared to go on the record with what seemed an obvious exaggeration of the threat of the next giant iceberg to drift towards South Georgia.