Carlos Solis
Satellite data that has tracked iceberg A-23A for decades reveals that this massive iceberg, which is breaking apart, has transformed from white to a vivid blue in a very short time. The reason is the melting water accumulating in cavities on its surface.
This change indicates that the iceberg, which has had a relatively long life, is nearing its end. The melting water is likely to accelerate its disintegration.
“I certainly don’t expect A-23A to last until the end of the Australian summer,” says Chris Shuman, a retired geologist who previously worked at the University of Maryland in Baltimore.
What’s Happening with A-23A?
Icebergs come in various colors for several reasons. Many of these icy formations are white because air bubbles trapped in the ice during formation increase light scattering and reflection.
As the ice ages, it compresses, forcing out the air bubbles and becoming more transparent. Impurities trapped in the ice can give it a greenish hue. Pure ice, meanwhile, tends to have a bluer tint.
However, something different is happening with A-23A. This 40-year-old iceberg is not a classic blue iceberg: as it rapidly melts, it is drifting in the warm waters at the boundary of the Southern Ocean and the South Atlantic, between the Falkland Islands and South Georgia.
After breaking off from the Filchner Ice Shelf in 1986, A-23A grounded on the Weddell Sea seafloor, where it remained relatively unchanged for about 30 years. By 2023, it finally broke free. Then it got caught in a swirling current known as the Taylor Column for several months before breaking free again and continuing its dramatic journey.
After that, A-23A became stuck on the seabed once more, only to free itself again and begin its final movement.
On the Brink of Total Disintegration
The demise of iceberg A-23A has been building for several months, according to Science Alert. Researchers have observed increasingly larger chunks breaking off from it. In January 2025, its estimated area was 3,640 square kilometers, making it the largest iceberg in the world at that time. By September, after A-23A lost several large chunks, its area shrank to 1,700 km². Now, it measures only 1,182 km².
This once-massive ice block is unlikely to last much longer. NASA has reported that A-23A is “on the brink of total disintegration,” as melting water fills its weaker cracks and causes them to widen more rapidly.
Currently, A-23A is heading toward an area known as the iceberg graveyard near South Georgia. There, the iceberg will melt away and eventually merge with the ocean.
“I’m incredibly grateful that we had satellite resources that allowed us to track it and meticulously document its evolution. A-23A will meet the same fate as other Antarctic icebergs, but its journey has been remarkably long and eventful. It’s hard to believe it will soon be gone,” Shuman reflects sadly.
Photo: NASA
