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World's Largest Iceberg A23a Nears Complete Melting After 40-Year Journey

Key Points
  • The world's largest iceberg A23a has only weeks left before completely melting after nearly 40 years at sea.
  • The iceberg originally measured 4,000 square kilometers when it broke off from Antarctica in 1986.
  • NASA reported the iceberg had shrunk to 1,500 square kilometers by September 2025 and is now melting rapidly in warmer waters.

The world's largest iceberg, known as A23a, is reportedly in its final weeks before completely melting, according to scientific assessments reported by Swedish media. The massive iceberg, which broke off from Antarctica in 1986, has been drifting in the ocean for nearly four decades. At its peak size, A23a measured approximately 4,000 square kilometers - larger than the Swedish island of Gotland.

After being stuck on the seafloor in the Weddell Sea for over 30 years, the iceberg began moving northward in 2020. It recently entered warmer waters where it has been melting rapidly. NASA reported last September that the iceberg had shrunk to about 1,500 square kilometers.

Researchers now estimate it has only weeks remaining before disappearing completely. While iceberg calving is a natural process, scientists note that climate change is causing more icebergs to break off from Antarctica than in previous decades.

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