Reef-building corals cannot survive if the water keeps warming. Corals rely on algae living inside them to supply them with food. These algae, which create the brilliant colors of healthy coral, die if the water gets too hot. The loss of the algae leaves the coral with a bleached appearance and leads to starvation.
Not only are ocean waters warming, but they also absorb more carbon dioxide (CO2)—a greenhouse gas that contributes to climate change. CO2 alters the ocean’s pH balance, which makes it more acidic and toxic to some marine organisms. Shellfish and corals are extremely vulnerable to ocean acidification because it interferes with their ability to form hard skeletons. Climate change also causes sea levels to rise—a big threat to coastal communities in the Coral Triangle, as well as to beach-dependent species such as marine turtles.