Ice in Antarctica is supposed to form from the top down, the result of falling snow. But researchers who scanned an Antarctic mountain range with lasers and radar have discovered new ice developing at the bottom of miles-thick ice sheets ... and altering the surface. The earth’s heat melted the glaciers from below, and the water refroze, notes NPR—leaving "plumes" of ice thousands of feet thick. While scientists have known for more than a decade that liquid water forms under the continent, "this is showing that the water can actually change the overlying ice sheet"—so forcefully, in fact, that it can alter the shape of the surface as far as two miles above.
And this could throw a wrench in the way scientists study past climates on Earth. Typically, scientists drill through ice sheets and study air bubbles within them. “You think of each layer in the ice sheet being a history book and telling us what was going on on the planet at that time,” says one expert. But these plumes of new ice don’t hold those records, so “unfortunately, these books have been erased." That’s going to make it harder to track down evidence of ancient climates—though data already stretches back some 800,000 years.