Satellites Watch World's Largest Iceberg Break Away From Antarctica

An enormous iceberg, the largest on record, has broken away from the Brunt Ice Shelf in Antarctica, satellite images have revealed. The colossal chunk of ice, dubbed A23a, measures an astonishing 4,000 square kilometers (1,500 square miles), making it more than three times the size of New York City.

The iceberg's calving was first detected in May by the British Antarctic Survey (BAS), and its movement has been closely monitored ever since. It is now drifting away from Antarctica towards the Weddell Sea, where it is expected to remain for several years before eventually breaking up into smaller pieces.

The calving of A23a is not entirely unexpected, as the Brunt Ice Shelf has been showing signs of instability for some years. However, the sheer size of the iceberg is remarkable, and it is a reminder of the ongoing impact of climate change on Antarctica's ice sheets.

"This is a significant event, and it is a reminder of the fragility of the Antarctic ice sheet," said BAS glaciologist Dr. Laura Gerrish. "The calving of A23a is a natural process, but it is also a consequence of climate change. The warming of the atmosphere is leading to the melting of ice shelves, and this is contributing to the destabilization of the ice sheet."

The loss of ice from Antarctica is a major concern, as it contributes to sea-level rise. If all of the ice on Antarctica were to melt, sea levels would rise by about 60 meters (200 feet), inundating coastal cities around the world.

The calving of A23a is a stark reminder of the urgent need to address climate change. The world must take action to reduce greenhouse gas emissions and prevent further warming of the planet. If we do not, the consequences will be catastrophic. 

A23a is a large tabular iceberg which calved from the Filchner–Ronne Ice Shelf in 1986. It was then stuck on the sea bed for many years but then started moving in 2020. Its area is about 3,900 square kilometres (1,500 sq mi), which made it one of the largest icebergs in the world until it was temporarily surpassed in size by A76.

In November 2023, A23a was tracked moving past the northern tip of the Antarctic Peninsula and headed toward the Southern Ocean.

The base Druzhnaya I was placed on this iceberg, until it calved. Subsequently, a rescue mission was started in 1987 and ultimately moved/renamed the base to Druzhnaya III.