In Antarctica, an iceberg the size of Liguria risks breaking away from the ice shelf. The Larsen C platform is under threat, and geographical maps could change forever.
An enormous block of ice covering 5,000 square kilometres, almost the size of Liguria, is about to break away from the Antarctic Peninsula. When it does, the Larsen C ice shelf – a glacial mass formed by the flow of glaciers and ice sheets from the mainland into the ocean – will lose more than 10 per cent of its extent, changing the geographical maps of the Earth as we know them.
Scientists from the Midas project, a British Antarctic research project aimed at monitoring the effects of climate change in the area, have revealed that the crack already present in the shelf expanded suddenly in the second half of December. Today, only 20 kilometres of ice are keeping the iceberg attached to the shelf and preventing it from floating freely in the Antarctic Ocean. However, even though the cause could be linked to global warming, scientists say there is currently no evidence to confirm this.
Researchers have warned that the loss of such a quantity of ice could make the structure of the Larsen C shelf less stable. Some previous research and experience shows that, following the break, the Larsen C shelf could meet the same tragic fate as the Larsen A shelf, which collapsed in 1995, and, even more significantly, Larsen B, which disintegrated in 2002 after a similar calving episode.
"The calving of this enormous iceberg could be the first step in the collapse of the Larsen C shelf, which would cause a vast area of ice to disintegrate into numerous smaller icebergs and fragments," said glaciologist David Vaughan, director of the British Antarctic Survey (Bas).
Even though scientists do not know when or how quickly the shelf will disintegrate, they warn that the crack will certainly make the shelf less stable. "Over the coming months, or years, we should expect further calving events, or even collapse. It is a very difficult thing to predict and our models show that the shelf will be less stable, but not that it will collapse immediately," Adrian Luckman, professor and head of the Midas project, told the BBC.
As it is part of the ice shelf, the calving of the iceberg would not directly cause sea levels to rise. However, scientists fear that a reduction of this magnitude in the ice shelf could accelerate the movement of ice from the mainland into the ocean. If all the ice supported by the Larsen C shelf were to end up in the ocean, sea levels would rise by 10 centimetres.
Fortunately, scientists confirm that the likelihood of this occurring in the future is remote, for now. According to a study conducted by Nature Climate Change, the Larsen C shelf holds back ice only passively, so the calving would not affect the flow of ice from the mainland into the ocean.
Translated by Camilla Soldati
