El Niño 2023: How Much Coral Will Bleach?

Scientists remember the years between 2014 and 2017 as a particularly bad time for coral reefs. Elevated temperatures fueled by an El Niño climate pattern harmed about three-quarters of the world’s reefs in both hemispheres, forcing corals to release their life-sustaining zooxanthellae and turning them ghostly white in a process known as coral bleaching.