Rising Tides

Daniel Grossman profiles Paul Hearty, otherwise known as "The Rock Whisperer," who believes ancient rocks hold the key to figuring out how fast and how much polar ice will melt due to climate change:

Such predictions matter tremendously. The world’s glaciers and ice sheets hold about two percent of Earth’s water. It’s a small fraction, but if all of it—about 6 million cubic miles of water—melted and poured into the oceans, the sea would rise by more than 230 feet. Most of today’s largest cities would vanish. A map of this waterlogged world would be missing Florida, the eastern shore of Maryland, Bangladesh, and Denmark.