In the past eight years, sea ice in Antarctica has reached a new record low four times, the Australian Broadcasting Corporation (ABC) reports. The first three times, ice levels that have dropped in the summer have rebounded in the winter.

But this year — during what is currently winter in Antarctica — scientists have confirmed that the ice is not re-forming, leaving long stretches of the Antarctic coastline bare.

What’s happening?

According to physical oceanographer Edward Doddridge, this is the first time an event like this has been observed, the ABC reports — and it’s extremely unlikely to have happened on its own.

“To say unprecedented isn’t strong enough,” Doddridge told the ABC. “This is a five-sigma event. … Which means that if nothing had changed, we’d expect to see a winter like this about once every 7.5 million years. … There are people saying it could be natural variability … but it’s very unlikely”.

Continue here: TCD