More than 80 percent of the world’s reefs have been exposed to the worst bleaching event in history, according to a report from NOAA and the International Coral Reef Initiative. Coral reefs—dubbed the “rainforests of the sea"—are a vital part of the marine ecosystem.

Coral reefs have long been losing their color due to bleaching, but a recent uptick has caused nearly all of the world's reefs to be damaged. A record-breaking amount of marine life fell victim to the bleaching, and scientists say the effects may be irreversible.