Drivers of Antarctica’s dramatic sea ice decline could accelerate global warming: new research

For decades, Antarctic sea ice appeared resistant to global warming. Now, scientists say a cascade of ocean and atmospheric changes has ‘flipped the system’ – and the consequences could accelerate climate change worldwide.

For many years, as Arctic sea ice thinned and shrank in step with a warming planet, the frozen waters surrounding Antarctica – the other end of the world – appeared stable. The sea ice even expanded in the late 2000s.

While scientists were actively looking for answers, testing how Antarctica had escaped the consequences of a warming planet, sea ice levels then took a U-turn and dropped to record lows.

An international study published today in Science Advances shows the reasons why – and the consequences could be profound.

Lead author Dr Aditya Narayanan from the University of Southampton and a visiting Research Fellow based at the Centre for Marine Science and Innovation at UNSW Sydney says a ‘triple whammy’ of interacting climate processes tipped the Southern Ocean into a new state – which triggered a sudden and dramatic decline in Antarctic sea ice after 2015.

“First, greenhouse gas emissions and the ozone hole strengthened the winds surrounding Antarctica,” Dr Narayanan says.

“This hauled warm, salty water up to the surface. Then the mixing of that water unleashed its heat,” he says.

“And this resulted in a feedback loop that has since kept sea ice in a prolonged low state.”