West Antarctica's ice cap threatened by northerly winds

It's not the westerly winds , as previously thought, but rather the northerly winds that are driving the melting of the West Antarctic ice sheet . This was discovered thanks to a series of simulations conducted under the guidance of Gemma O'Connor of the University of Washington and published in the journal Nature Geoscience. The result profoundly changes climate scenario forecasts.

The rapid melting of the West Antarctic ice shelves, a vast area bordering the Amundsen Sea , has been a real puzzle for years because it is occurring at a much faster rate than predicted by rising air temperatures alone. Ocean currents play a key role , with the arrival of warm currents that erode the ice from below , reaching the sea. This erodes the ice, forming tongues that act as props to limit the sliding of the ice masses on the continent.

Until now, it was believed that the phenomenon was somehow favored by high-altitude westerly winds, but this was unconfirmed. Now, based on new data and new types of computer simulations, researchers have solved the mystery. The source of it all seems to be the winds blowing from the north and their effect on the polynyas , ice-free stretches of sea, a sort of islands of water in the middle of the ice floe.

Models show that northerly winds reduce the formation of these fractures , which are pores that allow heat from the water to be released into the atmosphere . "But when northerly winds close the polynyas," said Kyle Armour of the University of Wisconsin, "ocean heat loss is reduced, which translates into warmer waters and increased melting of subsurface ice shelves ." This dynamic is further exacerbated by the fact that melting ice, water with a lower salt concentration , in turn attracts more warm water. This self-perpetuating mechanism is capable of altering ocean circulation.