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.

There is a kingdom of coral ... shelf that falls off, as if at the end of the world, into an abyss a mile and a quarter deep; and underwater mountains crowned, over the course of millennia, by reefs.

Lady Musgrave Island’s lagoon, part of a 3000-acre living reef, is nature’s own aquarium –­ pristine, wondrous, and now home ...