Loading video... VIDEO: Scientists were stunned to find frozen plant fossils--twigs and leaves--preserved under a mile of ice on Greenland. The discovery, explained in this video, helps confirm a new and troubling understanding... view more Credit: Quincy Massey-Bierman In 1966, US Army scientists drilled down through nearly a mile of ice in northwestern Greenland--and pulled up a fifteen-foot-long tube of dirt from the bottom. Then this frozen sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017. In 2019, University of Vermont scientist Andrew Christ looked at it through his microscope--and couldn't believe what he was seeing: twigs and leaves instead of just sand and rock. That suggested that the ice was gone in the recent geologic past--and that a vegetated landscape, perhaps a boreal forest, stood where a mile-deep ice sheet as big as Alaska stands today.