A seaplane flies over one section of Australia’s fourteen-hundred mile-long Great Barrier Reef, one of the planet’s most dynamic, productive, beautiful, and imperiled storehouses of biological diversity. The reef was one of the biggest victims of the most extended and far-reaching heat-driven episode of coral bleaching on record, which ended in 2017. By some estimates, half the reef saw widespread coral death. Human-propelled climate change is considered a dominant driver of the hot spells. At the same time, though, scientists have found sources of resilience in heat-tolerant variants of the algae that live in symbiosis with corals. There is also evidence from a 2018 study that the reef was able to withstand several periods of rapid sea-level change and rising flows of choking sediment over the past thirty thousand years. That research, done by drilling in the seabed to find past reef locations, was also sobering. It took hundreds, or even thousands, of years for the reef to recover after the starkest shocks. Queensland, Australia.