The Adventures of Iceberg A23a Continues

Been a while since I've written about something not golf or beer related, but it's been a busy few months.

Anyway, a while back I wrote about A23a, an iceberg caught in an ocean current that was spinning in place like the world's largest top. In the following months, A23a managed to break free, but now it's potentially heading for more trouble: a collision with South Georgia Island. This is hardly an unprecedented threat, as a similarly large iceberg threatened the island in 2020, but it is worth observing. Scientists have anticipated A23a will break apart into smaller, relatively harmless chunks, but that hasn't happened yet, so we still have a block of ice the size of Rhode Island bearing down on a vital piece of land for numerous forms of wildlife. Plus, anything living on the ocean floor would quite obviously be crushed as the enormous iceberg grinds to a halt on the island's continental shelf.

A23a doesn't pose much threat to people, fortunately, as the only resident of South Georgia are researchers, and the Southern Ocean isn't exactly well-traveled water for ships. But it's been a bit of a media hog, as far as state-sized icebergs are concerned, so I wouldn't be surprised if it does manage to hold together and run into the island, just for that last bit of news glory.

You Spin My Iceberg Right 'Round

(For full effect, here's a link to the song for some appropriate mood setting.)

The world's largest iceberg is spinning right 'round, like a record. And it'll be doing so for a long time.

You'd probably like some context to that statement.

Way back in 1986, an enormous iceberg, even larger than Rhode Island, split off from Antarctica's Filchner-Ronne ice shelf. Dubbed A23a (not a particularly catchy name), it almost immediately hit the bottom of the sea, sitting in place for over 30 years until 2020. At that point, A23a melted enough to drift free, resuming a long journey north to join the Antarctic Circumpolar Current. And while A23a is certainly much larger than your average iceberg, its fate would eventually be the same, drifting along until finally the last ice melted.

But before all that could happen, something rather amusing happened: A23a passed directly over a seamount. And not just any seamount, but the Pirie Bank Seamount, which juts out about a kilometer above the surrounding abyssal plain. Crucially, this seamount is slightly larger than A23a (roughly 60 by 60 kilometers), which made the iceberg the perfect size to get caught in something called a Taylor column – a vortex formed by ocean currents hitting and flowing around the seamount. 

The end result is something scientists say they've never seen before, as this enormous iceberg spins round and round (completing one rotation in roughly 25 days), trapped by the currents flowing around it. Not only did the A23a have to hit the bulls-eye with quite literally the entire Southern Ocean to play with, the conditions around the seamount also had to be correct (the water had to be flowing at certain speed, not too fast or to slow) in order to capture the enormous block of ice trundling overhead.

While the conditions keeping A23a in place will eventually end, releasing it from its 80s pop music prison, it will likely take a few years before the iceberg can continue on its merry way. Until then, we need to find the world's largest needle ... what? It's spinning like a record, maybe we ought to treat it like one. I'm all for guitar solos longer than your average geologic epoch.

Expanding Ice in a Warming World

The planet is getting warmer. This is a fact, backed by data. This year is looking to be the warmest on record, even if the year doesn't end all that warm. However, it is important to note that despite this fact, the world has not gotten warmer overall, and that some regions may not behave how you might expect.

This year, Antarctic sea ice covered 7.72 million square miles, the biggest area since the 1970's, when accurate measurements began. It's theorized that changing wind conditions from global warming have caused cold air to move across the Ross Sea, allowing for large scale ice expansion, since there's no land to stop anything. Warm air has instead started moving across the Antarctic Peninsula, and it's worth noting that ice coverage in that area has shrunk from past years.

Another area that is not behaving as expected is half a world away, in the Himalayas. Glaciers in the Karakorum region are not shrinking like other glaciers in the area, and if anything, are expanding. As the planet warms, the Himalayas receive more moisture, and for most mountains, this moisture comes in the summer, as rain. Because of geography, the Karakorum receives most of its moisture in the winter, so it falls as snow, feeding the glaciers in the area.  So again, even though the area is warming, not everywhere behaves the same way. It is important to note that while some glaciers are expanding, many are not, and that some inconsistency does not mean global warming is not an issue. It would be more remarkable if every place on the planet was warming in the same way.