Last year's marine heat waves were unprecedented, forcing researchers to make 3 new coral reef bleaching alert levels

Temperatures in parts of the world got so hot last year that it caused certain areas of the ocean to experience hot tub-level temperatures, which killed off essential coral reefs. The situation was unprecedented, to the point that researchers had to add three new levels to a coral bleaching warning system in an attempt to better protect marine life. 

The National Oceanic and Atmospheric Administration's Coral Reef Watch program, which uses satellites and models to monitor coral reef systems worldwide, said it revamped its bleaching alert system "in response to 2023's unprecedented marine heatwaves." 

"The revised system provides additional detail to help coral reef managers prepare for and take action during times of extreme heat stress," the program said on social media.