Plant fossils, frozen under a kilometer and a half of ice in Greenland, represent a worrying indicator that this ice sheet has completely melted in previous warm periods. This is shown by the new study, published in the journal ‘Proceedings of the National Academy of Sciences’, provides solid evidence that Greenland is more sensitive to climate change than previously believed, and runs the risk of melting irreversibly. In 1966, US Army scientists drilled nearly a mile of ice in northwestern Greenland and pulled out a fourteen-foot-long tube of earth from the bottom. Then this frozen sediment It was lost in a freezer for decades and was accidentally rediscovered in 2017.