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 way, with some locked in over the next century—pose an immediate threat to the survival of certain island nations and high-alpine communities, as well as hundreds of millions of other coastal inhabitants and many of the world’s fisheries. “The reason we have taken to the streets is because of science,” Thunberg said, after thanking the U.N. scientists who authored the report. “This is about an existential crisis for the biosphere and for humanity.” On the projection screen behind her was a seal stranded on a tiny iceberg in a big blue ocean. “Our main enemy now is physics. We can still fix this, it is still possible, but not if we continue like now.” She concluded, “We must listen to the scientists.”