Nearly 40 years after breaking off Antarctica, the colossal iceberg A23a, one of the oldest and largest ever recorded, is disintegrating in warmer waters and could vanish within weeks. Earlier this year, the 'megaberg' weighed nearly a trillion tonnes and was more than twice the size of Greater London.
The iceberg, which calved from the Antarctic shelf in 1986, spent over 30 years grounded in the Weddell Sea before escaping in 2020. It drifted along 'iceberg alley' into the South Atlantic Ocean, briefly threatening penguin feeding grounds near South Georgia island before moving on.
Satellite images from the EU’s Copernicus programme show the iceberg has shrunk to 1,770 sq km (683 sq miles) and 60 km at its widest point. In recent weeks, enormous chunks of about 400 sq km have broken off, with smaller fragments littering the surrounding sea.
Andrew Meijers, a physical oceanographer from the British Antarctic Survey, described the breakup as 'fairly dramatic'. He said: 'It’s basically rotting underneath. The water is way too warm for it to maintain. I expect it won’t be really identifiable within a few weeks.'
Scientists were surprised the iceberg lasted so long. 'Most icebergs don’t make it this far,' Meijers noted. Iceberg calving is natural, but the rate of ice loss from Antarctica is increasing, likely due to human-induced climate change.
