The rapid collapses of two ice shelves on the Antarctic Peninsula over the last 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 the lead author of a study describing the research in the journal Communications Earth and Environment.
While there have been no collapses on the peninsula since 2002, Dr. Wille and his colleagues found that atmospheric rivers also triggered 13 of 21 large iceberg-calving events from 2000 to 2020.