Paul Bierman's discovery that Greenland's ice sheet melted when Earth was no warmer than it is today sounds an alarm for our planet.In 2018, frozen soil from the bottom of the world's first deep ice core, lost for decades, reappeared in Denmark. When geologist Paul Bierman and his team analyzed this material, it led them to a startling Greenland's ice sheet melted naturally 400,000 years ago. That meant the ice was unstable even without human interference. In When the Ice Is Gone , Bierman traces the story of this pivotal discovery, delving into the nuances of polar science and arctic history. He explains how scientists, across more than a century, learned to read the language of ice and snow. He describes how engineers drilled the ice core at Camp Century, a Cold War military base built inside the ice sheet. And he explores the cataclysmic events the discovery portends if we don't address climate change, urging us to heed the warning from the ice and understand Greenland's significance for our collective future.