The researchers are interested in Totten not only because of the massive global consequences were it to be destabilized, but also because it could help solve a riddle from the Earth’s past. Researchers have calculated that during previous warm eras, such as during the Pliocene, about 3 million years ago, global temperatures not too much higher than those that exist today led to radical amounts of sea level rise. It’s too much of an ocean surge for the loss of West Antarctica, alone, to explain — so they’ve been going looking to East Antarctica to close the sea-level budget from those eras.

And it turns out that like West Antarctica, East Antarctica features several regions — including Totten — where massive amounts of ice rise above the ocean level, but are grounded deep below it. In the case of Totten glacier, its so-called “grounding line,” which is where the glacier begins to lift off the seafloor and to float, forming an ice shelf with an ocean cavity beneath it, is nearly a mile and a half deep.

Granted, none of this means that Totten is contributing much to sea-level rise — yet. The large loss of ice from the ice shelf doesn’t raise seas because that ice is already afloat. But the weakening of the ice shelf is troubling because the shelf holds back Totten’s more dangerous ice, and when it goes it will allow that ice to flow more easily into the ocean.

For Blankenship, the new study, combined with past aircraft and satellite research on Totten, puts the remaining piece in place and suggests an increasingly clear picture of ocean-driven melt that could lead to growing instability.

“The whole process is here and going on,” he says. “This is the biggest potential contributor in East Antarctica. It needs to be understood.”