“Over the last 15 years, it looked like we wouldn’t have to worry too much about the Greenland ice sheet melting too fast,” Schaefer said. “Most of the climate models treated it as a solid ice cube sitting on bedrock. With climate warming, it melts off the top, but it takes a long time. Compared to other ice sheets like West Antarctica, is looked pretty strong and resilient to warming.
“New, direct samples of the bedrock pierced that belief.”These might be the most precious rocks since the moon rocks,” he said. “We got the huge privilege of working with these rocks, and cutting-edge isotopic tools, and the surface of Greenland gave us a very clear answer. Unfortunately, the answer is it was ice-free during an important period.”