PLANET EARTH
The rate at which the West Antarctic ice sheet is melting will accelerate over the coming decades and is now an unavoidable consequence of climate change. Even if countries manage to cap greenhouse gas emissions and limit global temperature rise to 1.5 degrees Celsius above pre-industrial levels, the target adopted by world leaders in the 2015 Paris Agreement, melting will increase three times faster over the rest of the 21st century than it did during the 20th. “It looks like we’ve lost control of the melting of the West Antarctic ice sheet,” said Kaitlin Naughten, a researcher at the British Antarctic Survey. “If we wanted to preserve it in its historical state, we would have needed action on climate change decades ago.”
Enough water is locked up in the West Antarctic ice sheet to trigger up to five metres of sea level rise. Currently, the biggest contribution to sea level rise from this region appears to come from floating ice shelves in the Amundsen Sea, which are melting as a result of warmer temperatures in the Southern Ocean. Naughten and her colleagues ran simulations on a supercomputer to predict how much of this melting could still be avoided by reducing greenhouse gas emissions. Taking into account climate events and variability, such as the global effects induced by El Niño, the researchers found little change in the rate of ice loss among four different scenarios outlined in the Paris Agre
