Greenland Ice Sheet (image) NASA/Goddard Space Flight Center Caption Under the Greenland Ice Sheet, scientists were greatly surprised to discover an ancient tundra landscape. The finding provides strong evidence that the Greenland Ice Sheet has persisted much longer than previously known, enduring through many past periods of global warming. Credit Joshua Brown, University of Vermont Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.