How a Saltier Ocean Could Upset the Climate

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TThe waters around Antarctica suddenly and unexpected to become more salty. This turns a trend of several decades from the salinity of the ocean falls, which had protected southern sea ice against fusion.

In the mid -1970s, early satellite imaging showed that massive holes were periodically formed in glacial caps, called polynyas. One of these recurring gaps – in the ice cap of the Weddell Sea – has so large that it has received a name, the Maud Rise Polynya (named after an underwater mountain which rises below). Sometimes this hole was larger than the state of California.

But in the intermediary decades, the upper layers of the southern ocean encircling the Antarctic refreshed – moving less salty. This stratification has helped maintain the upper levels of the water cooler to water, protecting sea ice like a kind of warmer and more salty waters below. Huge holes in sea ice have become smaller and less common, despite the warming planet. The Maud Rise Polynya has not been revised for almost 40 years.

More recently, the polya and compatriots of Maud Rise began to return. Robots and seating satellites have collected worrying data: the freshwater protection model at the top of the water column has suddenly changed. More salty and warmer waters from below are now mixed on the surface, gnawing at sea ice much faster.

“The return of Maud Rise Polynya reports how unusual the current conditions are,” said Alessandro Silvano, an oceanographer from the University of Southampton who led the new research, in a press release. The study appears in the Proceedings of the National Academy of Sciences.

The results reversed certain climatic hypotheses on their heads. Most of the previous models provided that the reason for the South Ocean strongly in diapers would continue, helping to protect the sea ice store in the southern ocean, which is crucial to maintain the climate of the land as we know it. “Instead, a rapid reduction in sea ice – an important reflector of solar radiation – has occurred, potentially accelerating global warming,” said Aditya Narayanan, article co -author and postdoctoral researcher also at the University of Southampton, in a press release.

We still don’t know why this protective trend has reversed.

The work, largely funded by the European Space Agency, shows how little we know about the complex functioning of the dynamic and dynamic systems of our planet.

“If this salted and low ice state continues,” said Silvano, “it could permanently reshape the southern ocean – and with him, the planet.”

Main photo gracked from the University of Southampton

• Katherine Harmon Courage

  Published on July 1, 2025

  Katherine Harmon Courage is the editor -in -chief of Nautilus.