As sea ice melts in a warming climate, the Southern Ocean should be getting fresher. That’s what scientists expected to find when they analysed recent satellite data. Instead, they were astonished to find it’s actually getting saltier.
It likely means the delicate structure of the ocean has been upset, and relatively dense, warm, and salty water, which is usually held down by a fresher layer on top, is now bursting to the surface—accelerating ice retreat around Antarctica. The researchers speculate that stronger westerly winds, a consequence of climate change, might be to blame.
“We think this could be a regime shift,” says Alessandro Silvano from the University of Southampton, who led the research. “What the consequences are in the long term is an open question.”
