Credit: Joshua Brown, 2012
Under the Greenland Ice Sheet, scientists were greatly surprised to discover an ancient tundra landscape. "We found organic soil that has been frozen to the bottom of the ice sheet for 2.7 million years," said University of Vermont geologist Paul Bierman—providing strong evidence that the Greenland Ice Sheet has persisted much longer than previously known, enduring through many past periods of global warming. He led an international team of scientists that reported their discovery on April 17 in the journal Science.