A hole as large as the state of Maine (91,646 km² or 35,384 mi²) has opened up in Antarctica, and scientists are baffled by its sudden appearance.
The enormous, mysterious hole “is quite remarkable. It looks like you just punched a hole in the ice.” said atmospheric physicist Kent Moore, a professor at the University of Toronto’s Mississauga campus.
Areas of open water surrounded by sea ice, such the one pictured above, are known as polynias. They form in coastal regions of Antarctica. What makes this event strange, is that this polynia is deep in the ice pack, and must have formed through other processes that aren’t understood.
“This is hundreds of kilometres from the ice edge. If we didn’t have a satellite, we wouldn’t know it was there.” (It measured 80,000 k㎡ or 30,888 mi² at its peak.)
In the 1970s, a polynia was observed in the same location, in Antarctica’s Weddell Sea. Back then, observational equipment weren’t nearly as good as they are today, so that hole remained largely unstudied. Then it went away for four decades, until last year, when it reopened for a few weeks. Now it’s back again.
“This is now the second year in a row it’s opened after 40 years of not being there,” Moore said. (It opened around September 9.) “We’re still trying to figure out what’s going on.”
Scientists fear that the polynia will have a wider impact on the oceans.
“Once the sea ice melts back, you have this huge temperature contrast between the ocean and the atmosphere,” Moore explained. “It can start driving convection.” Denser, colder water sinks to the bottom of the ocean, while warmer water comes to the surface, “which can keep the polynia open once it starts,” he said.