Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything — vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised to discover an ancient tundra landscape preserved under the Greenland Ice Sheet, below two miles of ice.
The new discovery indicates that even during the warmest periods since the ice sheet formed, the center of Greenland remained stable; “it’s likely that it did not fully melt at any time,” Vermont’s Bierman said. This allowed a tundra landscape to be locked away, unmodified, under ice through millions of years of global warming and cooling.
Many geologists are seeking a long-term view of the history of the Greenland Ice Sheet, including how it moves and has shaped the landscape beneath it — with an eye toward better understanding its future behavior. It’s 656,000 square miles of ice, containing enough water, if fully melted, to raise global sea levels twenty-three feet — “yet we have very little information about what is happening at the bed with regards to erosion and landscape formation,” said Corbett.
What is clear, however, from an abundance of worldwide indicators, is that global temperatures are on a path to be “far warmer than the warmest interglacials in millions of years,” said Bierman. “There is a 2.7-million-year-old soil sitting under Greenland. The ice sheet on top of it has not disappeared in the time in which humans became a species. But if we keep on our current trajectory, the ice sheet will not survive. And once you clear it off, it’s really hard to put it back on.”