An iceberg that broke off from Antarctica in 1986 is now facing its final days as it rapidly turns blue. Earth satellites have been watching iceberg A-23A for decades, and recently, it transformed from a snowy white to a bright cyan. This change indicates that meltwater is gathering on its surface, speeding up its breakdown.
Chris Shuman, a retired Earth scientist, doesn’t think A-23A will survive the coming austral summer. The iceberg has been melting due to warmer waters in the Southern Ocean.
Icebergs come in various colors based on their composition. Most are white due to trapped air bubbles, which scatter light. As ice ages and compresses, it becomes more transparent. Pure ice is actually blue, but A-23A is melting rapidly rather than forming a typical “blue iceberg.”
After calving from the Filchner Ice Shelf in 1986, A-23A remained mostly stable for about 30 years in the Weddell Sea. However, by 2023, it started to drift and became trapped in a current called a Taylor column for months, before continuing its journey.
In early 2025, it wedged onto the seafloor, freeing itself later that year, but its condition worsened. Scientists observed chunks breaking off more frequently. Initially, in January 2025, A-23A measured around 3,640 square kilometers, making it the largest iceberg in the world. By September, its size had shrunk to about 1,700 square kilometers, and more recently, it’s now just 1,182 square kilometers.
The iceberg’s state destabilizes as meltwater pools in cracks, causing parts to break off faster. Satellite images also show a white rim around the iceberg, a phenomenon called a “rampart-moat effect.” This effect occurs as the ice bends and creates a barrier that traps meltwater, increasing pressure and causing leaks into the surrounding ocean.
Researchers expect A-23A is headed for an iceberg graveyard near South Georgia Island, where it will melt back into the sea. Shuman reflects on the significance of tracking this iceberg: “Its journey has been extraordinary, but it’s hard to believe it won’t be with us much longer.”
Additional Insights
Recent studies suggest that icebergs like A-23A are becoming more common due to climate change. According to the Intergovernmental Panel on Climate Change, melting ice sheets contribute to rising sea levels, which could impact coastal areas globally.
Social media users frequently react to dramatic iceberg changes, with viral posts showcasing A-23A and others. These conversations highlight public interest in climate issues and the urgency for action.
Icebergs may seem small, but they play a vital role in our ecosystem. As large ice masses melt, they affect ocean currents and wildlife habitats. Tracking these changes provides essential data as we confront climate challenges.
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