NASA, the United States aerospace agency, released last Thursday, 8, an image of the largest iceberg in the world, the A-23A, about to collapse, somewhere in the South Atlantic Ocean between the east of the South American continent and the island of South Georgia.
The A-23A separated from Antarctica in 1986. At the time, it measured 4 thousand km² – for comparison purposes, more than double the area of the city of São Paulo (1,521 km²) and close to the area of the Federal District (5.8 thousand km²). Since then, the iceberg has lost mass until it reached 1,181 km², close to the area of the city of Rio de Janeiro (1,200 km²).
In the satellite image, captured on December 26, it is possible to see the remaining parts of the iceberg soaked, with extensive pools of melted blue water visible on its surface.
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The next day, an astronaut on the International Space Station captured a closer image that showed even larger puddles.
The “blue” areas are likely the result of ongoing disintegration events, Ted Scambos, a senior researcher at the University of Colorado, explained to the NASA website. “You have the weight of the water inside the cracks in the ice, forcing them open.”
You can also see a thin white line around the outer edge of the iceberg, which appears to trap the melted blue water – a “bulwark-moat” pattern caused by a curvature of the iceberg as its edges melt at the waterline.
The satellite image suggests that the iceberg has a fissure, which could be the result of what retired University of Maryland scientist Chris Shuman described as “an explosion,” in which the weight of the water accumulated at the top would have created enough pressure on the edges of A-23A to pierce them. The “explosion” would have allowed meltwater to spread tens of meters to the ocean surface.
Scientists say these signs indicate the iceberg may be just days or weeks away from completely disintegrating. “I certainly don’t expect the A-23A to last until the end of the Southern Hemisphere summer,” Shuman said. He is already in waters that are around 3 degrees Celsius and being pushed by currents that take him to even warmer waters, which will quickly corrode him.
Even by Antarctic standards, A-23A has had a long and winding journey, filled with unexpected chapters that have improved scientists’ understanding of megaicebergs. After being stranded in the shallow waters of the Weddell Sea for more than 30 years, the A-23A broke free in 2020 and spent several months in a spinning ocean vortex called the Taylor column.
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It ended up turning and heading north, nearly colliding with the island of South Georgia and becoming trapped in shallow waters for several months before escaping into the open ocean, where it rapidly fragmented throughout 2025.
On the NASA website, scientists who followed the iceberg throughout its “life” said they had a bittersweet feeling about its imminent disappearance.
“I’m incredibly grateful that we had the satellite capabilities that allowed us to follow it and document its evolution so closely. A-23A faces the same fate as other Antarctic icebergs, but its journey was remarkably long and eventful. It’s hard to believe it won’t be with us for a long time,” said Shuman.
