Southern Ocean Saltier, Warmer, Antarctic Ice Loss Accelerates Since 2015

Recent research led by the University of Southampton reveals a dramatic and unexpected environmental shift in the Southern Ocean, with surface water salinity rising sharply since 2015 and Antarctic sea ice declining at a record pace, amounting to a loss roughly the size of Greenland. This reversal from decades of surface freshening weakens water stratification, allowing deep ocean heat to rise and melt sea ice from below, creating a dangerous feedback loop that accelerates ice loss and ocean warming. One striking consequence is the re-emergence of the Maud Rise polynya in the Weddell Sea, a large open water area within the ice that had not appeared since the 1970s. The decline in sea ice reduces Earth's albedo, leading to increased solar absorption, warmer oceans, stronger storms, and habitat loss for Antarctic wildlife such as penguins. This shift signals a possible tipping point into a new climatic state with global repercussions including rising sea levels and intensified weather extremes. Advanced satellite and underwater robotic monitoring have been crucial in detecting and understanding these rapid changes in this remote and harsh environment.