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Giant Iceberg A23a Melts Away After 40 Years
8 Mar
Summary
- A23a iceberg broke from Antarctica in 1986, covering 4,000 sq km.
- Stuck for decades, it finally drifted in 2020 and began melting.
- Scientists expect the colossal iceberg to fully disintegrate within weeks.
One of the world's oldest and largest icebergs, A23a, is nearing the end of its 40-year voyage across the Southern Ocean. Originating from Antarctica's Filchner-Ronne Ice Shelf in 1986 with an initial size of 4,000 square kilometers, it became grounded on the Weddell Sea seafloor for over three decades.
In 2020, A23a finally broke free and embarked on a northward journey, influenced by ocean currents and winds. It traversed "Iceberg Alley" and experienced a period of spinning within a Taylor column, a type of ocean vortex.
Upon entering the warmer South Atlantic waters, the iceberg began a rapid deterioration. Recent satellite observations reveal a dramatic shrinkage, with reports indicating significant melting, fracturing, and disintegration over the past year. By March 5, 2026, its size had reduced to 180 sq km from 3,600 sq km in January 2025.
Researchers are fascinated by A23a's unusual longevity and its subsequent rapid demise. As it melts, the iceberg releases nutrients that can boost marine productivity, though it also contributes slightly to global sea-level rise. Scientists now predict A23a's complete disintegration within weeks, concluding one of the longest-tracked iceberg journeys on record.
