It’s big, beautiful and blue. But this 40 year old iceberg is about to disappear forever
listen to this article
estimated 5 minutes
The audio version of this article has been generated by AI-based technology. There may be incorrect pronunciations. We are working with our partners to continually review and improve results.
A 40-year-old iceberg that was once the largest on the planet is floating in the South Atlantic Ocean, where it may soon melt into water.
But it is going out of style.
A-23A, as it is known, was discovered off Antarctica in 1986 and has attracted the attention of scientists ever since.
But the world’s eyes are now on the giant berg because of its brilliant blue pattern nasa satellite images Caught just after Christmas.
However, the spectacular splash is a sign that A-23a is in its final days, as it drifts away from what scientists call an “iceberg graveyard” some 2,800 kilometers away from where it broke up. Here’s what you need to know about the life and legacy of the A-23A.
more than 1 trillion tons
A-23a was once part of Antarctica’s Filchner Ice Shelf, which lies east of the Antarctic Peninsula that extends toward South America.
In 1986, a 4,000 square kilometer slab broke, or broke, creating a tabular iceberg – basically a flat-topped block of ice the size of Rhode Island and weighing more than a trillion tons.
But for a long time it did not go far from home.
It remained stranded at the bottom of the Weddell Sea until 2020, when it began its deadly journey north along the Antarctic Peninsula. Now, after some more grounding, it’s bouncing near South Georgia Island.
The A-23a is now much smaller. according to US National Ice CenterAs of Friday, it has shrunk to about 781 square kilometers after parts of it calmed down in warm waters.
Chris Shuman, a retired scientist, told NASA Earth Observatory It is unlikely that the A-23A would survive the Southern Hemisphere summer.
The world’s largest iceberg, known as A23a, is floating in open waters after being stuck on the ocean floor since the 1980s. It is flowing off the coast of Antarctica and could pose a threat to wildlife if it hits the sparsely populated South Georgia Islands.
a beautiful death
Icebergs of any shape and size are quite a sight to behold. But what people find attractive about the A-23A are the bright blue patches on its surface.
Ted Scambos, a senior research scientist at the University of Colorado at Boulder, told NASA Earth Observatory The blue muddy areas are probably meltwater accumulating on the surface of the ice as it slowly breaks apart.
“You have the weight of water that’s sitting inside the ice cracks and forcing them to open up,” he said.
Walt Meyer, senior research scientist at the National Snow and Ice Data Center, said the pattern effect appears to be stripes, parallel ridges, forming on the ice over time that “direct the flow of meltwater.” told NASA.
International climate correspondent Susan Ormiston embarks on the first all-Canadian voyage to Antarctica with 15 climate scientists and the crew of HMCS Margaret Brooke. She explains the geopolitical tensions at the far South Pole and what is happening in the region and what is at stake.
beyond the blue
White and blue might be the colors you expect to see on an iceberg. But what about green? Yellow? black too?
Scientists are investigating why some icebergs in the Weddell Sea turned a bright emerald or jade color, saying it could be due to ice reflect color of phytoplankton in water.
According to a 2019 article in Yellow Iceberg National GeographicThis may be the result of iron oxide-rich dust kicked up by the retreat of glacial ice on Antarctica’s bedrock.
“Ice filters red light, and iron oxides filter blue light, so when refracted sunlight reemerges from the iceberg, all that is left is green to escape,” Steve Warren, professor emeritus at the University of Washington, told the publication.
Then a rare black iceberg was seen there last spring On the coast of Labrador.
Local man Hallur Antoniosen told CBC Radio labrador morning It wasn’t just the dark color that was surprising – but also its diamond-like shape.
It is unclear what caused the color.
But Lev Tarasov, a physicist and glacial Earth system modeler at Memorial University in St. John’s, told CBC News at the time that it was possible the iceberg had rolled over at some point and that it was actually its bottom surface, blackened with dirt and rocks, that was visible above the water.
A ‘fatal’ turn for icebergs
It should come as no surprise that distant icebergs would move away from this area of ​​Antarctica as they approach warmer waters and begin to disintegrate in an area commonly referred to as the “iceberg graveyard.”
The Weddell Sea Gyre is a current that rotates clockwise and pulls icebergs northward from this part of Antarctica, on the same path that A-23a followed, and into the Scotia Sea and Drake Passage.
“The water at this latitude – about 54 degrees south – is generally warmer than the Southern Ocean and lethal for icebergs,” he said. NASA Earth Observatory. A-23a is located at approximately this latitude.
A satellite view of an iceberg seen on wednesday A significant part of the A-23A is seen breaking off on NASA Worldview.
As the oceans are warming and circulation patterns are changing, a Canadian science team is trying to collect water and sediment samples around Antarctica, hoping to find clues about what might happen to Earth’s past and future climate.
