For coral reefs, climate change is an existential threat. Australia’s Great Barrier Reef has endured seven mass bleaching events over the past 25 years. Five have occurred in the past eight years. But amid the story of decline, something curious is happening. Surveys from the air and on water show a few reef groups, such as the Ribbon Reefs in the far north and the Swains and Pompey reefs in the south, are consistently escaping severe bleaching while their neighbouring reefs suffer. But how? In our new research, we found their survival is due to cold water. That is, most…