Even under the most optimistic scenarios, most of the coral reef ecosystems on our planet—whether in Australia, the Maldives or the Caribbean—will have disappeared or be in very bad shape by the end of this century. That’s because global warming is pushing ocean temperatures above the limit that single-cell algae, which are corals’ main allies, can withstand. These algae live inside coral tissue for protection and, in exchange, provide corals with essential nutrients produced through photosynthesis. Because the algae contain a variety of pigments and therefore give coral reefs their famous colors, if they are lost the corals turn white, which is known as coral bleaching. But in spite of the real threat caused by global warming, corals in the Red Sea look set to keep their vibrant color.