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World's Largest Iceberg Vanishes in Southern Ocean
21 Apr
Summary
- The A23a iceberg, once the world's largest, has completely broken apart.
- It lost 99% of its original area, shrinking to less than 50 square kilometers.
- The iceberg broke off Antarctica in 1986 and has been tracked for 40 years.
The A23a iceberg, once recognized as the world's largest, has completely broken apart in the Southern Ocean. Scientists from the Arctic and Antarctic Research Institute (AARI) have been monitoring the frozen mass for 40 years. This disintegration means the iceberg has lost approximately 99% of its original area since its formation.
Originally breaking off from Antarctica's Filchner-Ronne ice shelf in 1986, A23a initially spanned 4,170 square kilometers. After more than three decades grounded in the Weddell Sea, it began a journey into open waters by November 2024. By the start of 2025, it neared South Georgia Island.
Significant fragmentation occurred in late August 2025, when three large pieces detached, reducing its size by about 70%. Although it lost its title as the largest iceberg, it continued to drift and break apart. As of the present, A23a's remaining area is less than 50 square kilometers, and it has traveled 1,000 kilometers in the past three months across the South Atlantic and Atlantic Oceans.
