Nearly one-fifth of the world’s coral reefs have already succumbed to the combined onslaught of global warming, water pollution, and overfishing. Without immediate measures to mitigate climate change and reduce the local pressures on reefs, the world is set to lose another 15% of coral reefs over the next 10−20 years and 20% over 20−40 years. Those are the main conclusions of a new report, produced jointly by a handful of government agencies and nongovernmental organizations from around the world, including the U.S. National Oceanic and Atmospheric Administration (NOAA).