How Oceans Rise and Die on a Warming Planet

In a Park Hyatt hotel ballroom in midtown Manhattan, on Wednesday, Greta Thunberg, the sixteen-year-old climate activist, stood before world leaders and delivered a goosebump-inducing speech. The occasion was the release of “The Ocean and Cryosphere in a Changing Climate,” a major scientific report by the U.N.’s Intergovernmental Panel on Climate Change, which concluded that human activities have made the oceans increasingly inhospitable to marine life and have caused glacial melt and sea-level rise to happen at an even faster rate than scientists had previously projected. The effects—already well under...