Southern Ocean freshened by sea ice

The Southern Ocean has become less salty during the past few decades. An analysis of sea-ice transport in the ocean suggests that this phenomenon can be explained by coupled changes in sea-ice drift and thickness. See Letter p.89 Antarctic ice freshening the oceans The Southern Ocean has freshened over the past few decades, but the underlying mechanisms involved have remained unclear. Alex Haumann and colleagues bring together multiple lines of evidence and — despite large uncertainties in the underlying datasets — they find that northward transport of sea ice formed around the Antarctic coast can explain the bulk of the observed freshening.