Unprecedented Movement: The World's Largest Iceberg Sets Sail
The colossal iceberg, over twice the size of London, has finally broken free from its decades-long anchorage on the Antarctic seafloor, marking an unprecedented moment in its remarkable journey across the vast ocean
The largest iceberg in the world, which is more than twice the size of Britain's capital city, is finally on the move after being stuck on the seafloor in Antarctica for decades. It broke away from the Filchner-Ronne ice shelf in 1986 and quickly grounded on the Weddell Sea floor.
The iceberg, known as A23a, measures approximately 400 meters (1,312 feet) in thickness and covers an area of nearly 4,000 square kilometers (1,544 square miles). To put that into perspective, Greater London spans 1,572 square kilometers (607 square miles).
West Antarcticahome to the Thwaites Glacier, also known as the "Doomsday glacier"is the continent's largest contributor to global sea level rise.
Jeremy Harbeck/OIB/NASA
The rapid melting of West Antarctica is inevitable, posing potentially catastrophic effects on rising sea levels, according to a recent study.
Now, nearly thirty years later, the iceberg has likely decreased in size enough to release its hold on the seafloor as part of the ice shelf's natural growth cycle, and has begun to drift, according to scientists Ella Gilbert and Oliver Marsh from the British Antarctic Survey.
A23a has been the largest current iceberg multiple times since the 1980s, although larger but shorter-lived icebergs like A68 in 2017 and A76 in 2021 have occasionally surpassed it. The iceberg is expected to continue eastward due to ocean currents, traveling at a rate of five kilometers (three miles) per day.
Gilbert and Marsh stated that although this specific iceberg likely separated as a normal part of the ice shelf's growth cycle, climate change is causing significant changes in Antarctica's ice, leading to the loss of large amounts of ice each year.
