Ofu Island – a speck of land emerging from the southwest Pacific Ocean – is a textbook paradise. Jagged, forest-covered peaks rise steeply from palm-fringed white sand beaches, as colorful birds sound off in the distance.

But beneath the waves, it’s a different story: Ofu Island’s coral reefs are suffering. As temperatures in some lagoons eclipse 35 °C on a daily basis, extensive coral bleaching is leaving a graveyard of rocky, spindly skeletons reaching into the warming water.

Corals