When the Ice Is Gone: What a Greenland Ice Core Reveals About Earth’s Tumultuous History and Perilous Future

Bierman, a geology professor at the University of Vermont, debuts with a granular account of studying Greenland ice cores. He recounts how in 2019, he joined an international team of scientists who stumbled upon long-neglected cores extracted from the Greenland ice sheet in the 1960s. Using them to reconstruct climatological history, the team discovered that Greenland’s ice sheet had melted at some point in the last million years, when atmospheric carbon dioxide levels were significantly lower than they are today. The implication is that the ice sheet is more fragile than previously believed, Bierman argues, warning that if it melts again, it could “put a half-million square miles of land underwater and displace several hundred million people.” Bierman presents an accessible discussion of the scientific methods used to date samples (to determine “the ages of boulders left behind by melting glacial ice... measure the concentration of isotopes in a sample and divide by the production rate of each isotope”). Unfortunately, extensive background on the logistical difficulties of maintaining the tunnel and heating systems at Camp Century, the northern Greenland U.S. Army outpost where the cores were collected, distracts from the book’s focus on climate change. The result is an intermittently stimulating glimpse into the workings of climate science. Photos. (Aug.)