A large swath of ice might be on the verge of breaking off of Antarctica and drifting off into the sea, according to Sky News.
Pine Island Glacier has a crack tens of kilometers long and is one of Antarctica's fastest flowing rivers of ice, moving 4,000 meters a year, according to the report.
"It looked to me incredibly unstable," British Antarctic Survey's Dr. Joanne Johnson told Sky News. "It is about to calve off, and it's a huge part of the glacier.
"To see that in front of me made me think, 'Gosh, this is really happening.'
"I haven't appreciated that in the same way before."
The West Antarctic Ice sheet is estimated to be 2.2 million cubic kilometers of ice, which, if it melted, would raise world sea level about 3 meters and submerge cities like London and New York, per the report.
While rising air temperatures can melt polar glaciers, it is now scientifically known warming oceans melt ice far more quickly, and a 2019 study has shown oceans are warmer than any time in recorded history, according to Sky News.
Pine Island Glacier, reportedly about three kilometers deep, is reportedly melting from underneath at a rate of 22 meters per year, according to the report.