The finding at the bottom of the world is in some ways the most shocking. Antarctica is split into two massive ice sheets, the East and the West. Researchers have long considered the East Antarctic Ice Sheet to be less worrisome: Though it contains enough frozen water to raise global sea levels by 173 feet, it sits at a high enough altitude to withstand the first century or so of warming.

The new finding may complicate that conclusion. Using a new database of global ice movements, NASA scientists found that several glaciers in the East Antarctic Ice Sheet are quickening their march toward the sea. Since 2008, a set of glaciers that feed Vincennes Bay—which is due south of Australia—lost about nine feet of overall height. Their speed has also increased, suggesting that these glaciers are dumping more ice into the ocean than researchers previously expected.

The Vincennes Bay glaciers are important because they block the inland Aurora and Wilkes ice basins from tumbling into the sea. If both basins collapsed, they could raise sea levels by 92 feet. “Taken together, they’re about four Greenlands [worth of sea-level rise],” said Catherine Walker, a glaciologist at NASA, speaking at the annual meeting of the American Geophysical Union on Monday.

Read: The pond at the North Pole

Alex Gardner, another glaciologist at NASA, said that warming oceans—and not just a warming climate overall—seemed to be causing the decline in glacier levels. Some of the fastest-collapsing glaciers in the world—such as the Jakobshavn Glacier in Greenland—are primarily giving way because of warm ocean waters wearing at their icy fronts.

Both researchers said that existing models of sea-level rise may not account for these changes. “We weren’t expecting it because we never knew it was happening,” Walker said. “This isn’t new; it started happening 10 years ago. We just couldn’t see it.”

Not that the other end of the world is doing much better. NOAA’s new Arctic Report Card—an annual analysis, now in its 13th edition—finds that the world’s Far North is going through a tremendous upheaval. The report says that the catastrophic effects of climate change now wreak mayhem in every season of the year.

In the winter, when the Arctic Ocean has historically frozen into an enormous skating rink, sea ice now struggles to form at all. 2018 was the second-worst year on record for sea ice, the report says. The Arctic is now so warm that it hemorrhages ice even at the coldest, darkest time of the year: “During two weeks in February—normally the most important weeks for sea-ice growth in the year—the Bering Sea actually lost an area of ice the size of Idaho,” said Don Perovich, a geophysicist at Dartmouth, on Tuesday.