Antarctica's sea ice started shrinking dramatically in 2015 after resisting global warming for decades, and researchers now know why. A study published May 8 in the journal Science Advances reveals that Antarctic sea ice succumbed to strong winds that disturbed the Southern Ocean's layers, replacing cold and relatively fresh surface water with warmer, saltier water that caused some initial melting. As sea ice declined over the years and reflected less sunlight back to space, the ocean absorbed more heat, thus accelerating the loss way beyond what scientists were expecting . In February 2023, sea ice in Antarctica hit its lowest extent since records began. (Image credit: European Union, Copernicus Climate Change Service data) To pinpoint what caused such sudden and rapid sea ice loss, Narayanan and his colleagues used a model and observations from satellites and sensors in the Southern Ocean.…