The world’s largest iceberg, A23a, is once again on the move, drifting through the Southern Ocean after months of being stuck in a rotating current, CNN reports, citing the British Antarctic Survey (BAS).
The colossal iceberg, measuring 3,672 square kilometers (slightly larger than Rhode Island) when last measured in August, has captivated scientists since it calved from the Filchner-Ronne ice shelf in 1986.
For over three decades, A23a remained grounded on the Weddell Sea floor before eventually becoming mobile. Ocean currents carried it away, only for it to become trapped in a Taylor column – a spinning vortex of water created by currents interacting with an underwater mountain. Now freed from this watery prison, the iceberg is expected to continue its drift towards warmer waters and the remote island of South Georgia. There, it is likely to break apart and eventually melt.
A23a has held the title of “largest current iceberg” multiple times since the 1980s, though other massive icebergs, such as A68 (2017) and A76 (2021), have briefly surpassed it in size. While scientists emphasize that A23a’s initial calving was likely a natural process and won’t directly contribute to rising sea levels, they highlight the concerning impact of climate change on Antarctica. These changes, they warn, could have devastating consequences for global sea levels.
BAS scientists have been closely monitoring A23a’s journey, studying its erosion and the influence of sea ice on global ocean cycles of carbon and nutrients. Biogeochemist Laura Taylor, who collected water samples around the iceberg, explained the research’s importance: “We know that these giant icebergs can provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less productive areas. What we don’t know is what difference particular icebergs, their scale, and their origins can make to that process.”
