A new study published in the Proceedings of the National Academy of Sciences has found that the Greenland Ice Sheet has added a quarter inch of water to global sea levels in just the past eight years. The research covers nearly 20 years previously not included in our detailed understanding of the troubled Greenland Ice Sheet. The paper finds that climate change has already bled trillions of tons of ice from the island reservoir, with more loss than expected coming from its unstable northern half. The paper's findings are stirring in part because they go much further back in time. "A lot of the publications about Greenland's mass start in 2000 or 2002, some go back to 1992, but this is the first time we go back another 20 years," said Eric Rignot, a senior scientist at NASA and an author of the paper.