His journey evokes the game “One, two, three, sun!”. The A23a iceberg broke away from Antarctica in 1986, but quickly froze in the Weddell Sea (Southern Ocean). The imaginary leader of the game was in no hurry: it would in fact take around thirty years before the ice giant could get moving again.
From 2020, glaciologists were therefore able to follow its progress. Except that in the spring of 2024, woes: A23a started filming on site. The iceberg was indeed caught in a “Taylor column”, a type of marine vortex, near the South Orkney Islands.
However, after long months of waiting, it has finally emerged from this rotating water column, announced the British Antarctic Survey (BAS) on December 13. Its trajectory is currently taking it north, say British scientists.
The fate of the iceberg
With its surface area of 3,800 km², equivalent to almost half of Corsica, A23a held the title of “largest iceberg today” on several occasions, sometimes dethroned by larger icebergs but with a shorter duration of existence, notably A68 in 2017 and A76 in 2021, recalls CNN.
The massive iceberg should eventually leave the Southern Ocean to enter the Atlantic Ocean. There, it will encounter warmer waters and will then break into smaller icebergs, before melting and disappearing completely, the researchers anticipate.
“It’s exciting to see A23a moving again after being stuck for a while”rejoices Dr Andrew Meijers, co-leader of the OCEAN:ICE project at BAS (press release). “We are curious to see if it will follow the same route as the other large icebergs that have calved off Antarctica. And above all, what the impact will be on the local ecosystem”he adds.
In its wake, the ice giant is expected to leave a valuable legacy for marine life. “We know that these giant icebergs can provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less productive areas”assures biogeochemist Laura Taylor, member of the BIOPOLE expedition crew (press release).
“What we don’t know is the difference that particular icebergs, their size and their origin can make in this process”she specifies. The water samples taken by his team near A23a last year should provide answers to this question.
Rising sea levels
Although it is unlikely that the melting of A23a will contribute to sea level rise, this iceberg having in fact broken away as part of the “natural ice shelf growth cycle”climate change is however causing upheavals in Antarctica, notes CNN, with “potentially devastating consequences” in terms of rising sea levels on a global scale.
The British Antarctic Survey’s latest report on the state of Antarctic sea ice, published last May, indicates that levels “historically low” were measured in 2023, completes El Mundo. More specifically, the study published in the journal Geophysical Research Letters indicated a negative deviation of two million square kilometers of ice compared to a winter “normal”.
