Limiting global warming to 1.5 degrees C above pre-industrial levels will still be catastrophic for coral reefs, new research suggests. More than 90 percent of tropical coral reefs will suffer frequent heat stress — their number one threat — even under Paris Agreement climate warming limits. The scale is even worse than predicted by the Intergovernmental Panel on Climate Change, which reported in 2018 that such a level would cause 70 percent to 90 percent of coral reefs to decline.