Scientists solve Antarctic ice collapse puzzle
The rapid collapses of two ice shelves on the Antarctic Peninsula over the past quarter-century were most likely triggered by the arrival of huge plumes of warm, moisture-laden air that created extreme conditions and destabilized the ice, researchers said Thursday.
The disintegration of the Larsen A shelf in 1995 and of the Larsen B shelf in 2002 were preceded by landfall of these plumes, called atmospheric rivers, from the Pacific Ocean. They generated extremely warm temperatures over several days that caused surface melting of the ice that led to fracturing, and reduced sea ice cover, allowing ocean swells to flex the ice shelves and further weaken them.
“We identify atmospheric rivers as a mechanism that can create extreme conditions over the ice shelves of the Antarctic Peninsula and potentially lead to their destabilization,” said Jonathan Wille, a climatologist and meteorologist at the Université Grenoble Alpes in France and lead author of a study describing the research in the journal Communications Earth and Environment.
Although there have been no collapses on the peninsula since 2002, Wille and his colleagues found that atmospheric rivers also triggered 13 of 21 large icebergcalving events from 200020.
Wille said the larger Larsen C shelf, which is still mostly intact and, at about 17,000 square miles, is the fourth-largest ice shelf in Antarctica, could eventually suffer the same fate as A and B.
“The only reason why melting has not been significant so far is because it's just farther south compared to the others, therefore colder,” he said. But as the world continues to warm, atmospheric rivers are expected to become more intense. “The Larsen C will now be at risk from the same processes,” he said.
Kyle Clem, a researcher at Victoria University of Wellington in New Zealand who was not involved in the study, said the work also showed that other parts of Antarctica that are not warming as fast as the peninsula could eventually be susceptible as well, since the mechanism that the researchers documented is more dependent on warming where the atmospheric river originates.