A hole the size of Maine has formed in the ice in Antarctica’s Weddell Sea, and scientists have no concrete theory as to why.
This patch of water among miles of ice appeared about a few months ago during a time when the ice is normally very thick, and because of its remote location, researchers are mostly relying on satellite imagery to study it.
The going theory on what caused it has to do with water currents and a flow of warmer water rising up and melting the ice.
Under certain circumstances, that warmer water can break through the insulating cooler water and melt the ice—a phenomena that happens regularly around coastal areas in both the Arctic and Antarctic, but normally not in the middle of the sea.
The warm water cools when it reaches the air, then sinks to the bottom and reheats.
This is the second time in two years the opening in the ice—called a polynya—has appeared. The last time it happened was in 2016.
Many climate scientists thought that, based on their theories of climate change, the formation of this deep-sea polynya would not form again in the Antarctic. Because there is a 40-year span between the last time this happened, there’s no clear pattern for scientists to follow.
“Two of these events happening two years in a row really isn’t a long enough kind of trend for us to say it’s the result of global warming,” Moore told CBC.