Large Antarctic Iceberg Facing Collapse

Nasa has announced that one of the largest icebergs closely monitored since it broke away from Antarctica 40 years ago is at risk of “complete collapse.” The iceberg, known as A-23A, initially measured twice the size of Rhode Island when it finally detached in 1986—a year when Ronald Reagan was President and Top Gun was breaking box office records.

Now, it’s floating in the South Atlantic Ocean between South America’s eastern tip and South Georgia Island. Back in 1986, the iceberg was over 1,500 square miles, but recent estimates from the U.S. National Ice Center suggest it has shrunk to about 456 square miles this year after losing significant chunks to warmer temperatures last summer.

Iceberg Observations

Despite its smaller size, A-23A still ranks among the world’s largest icebergs, eclipsing even New York City in scale. Recent satellite imagery from NASA taken shortly after Christmas revealed the iceberg’s stunning blue hue, enhanced by snowmelt. Close-up images captured by scientists aboard the International Space Station the following day showed an even larger melt pool.

Remarkably, the blue and white stripes visible on the iceberg may date back hundreds of years, indicating when a part of the glacier was dragging over Antarctic rock.

Chris Schuman, a retired scientist from the University of Maryland, Baltimore County, remarked on the continued visibility of those stripes even after extensive snowfalls and meltings over the years. The iceberg also seems to be “leaking,” as water accumulation at its top is creating enough pressure to force it out at the edges, according to NASA’s observations.

Scientists are uncertain about the timeline for A-23A’s potential breakup, estimating it could occur in days or weeks.

Future of A-23A

Schuman expressed skepticism about A-23A’s chances of surviving into the Southern Hemisphere summer, which takes place from December to February. NASA noted the iceberg’s journey has been both lengthy and unpredictable, providing valuable insights into the behavior of large icebergs, often referred to as “megabergs,” released into the Southern Ocean.

The iceberg spent more than three decades in the shallow Weddell Sea before it was released back in 2020. It was entangled in an ocean vortex for several months, later moving north and nearly colliding with South Georgia Island, east of the Falkland Islands, before drifting into more open waters and deteriorating rapidly last year.