The world’s main system for warning about heat stress on the planet’s coral reefs has been forced to add three new alert categories to represent ever-increasing temperature extremes. The changes introduced by the US government’s Coral Reef Watch program come after reefs across the Americas were hit by unprecedented levels of heat stress last year, bleaching and killing corals en masse.

Coral Reef Watch, hosted by the National Oceanic and Atmospheric Administration, previously issued warnings for coral reefs in four stages, with the highest, alert level 2, suggesting that “severe bleaching and significant mortality [is] likely”. Now the program has added three further alert levels to a program used by scientists, conservationists, marine park managers and citizen scientists around the world to understand the conditions being faced by coral reefs in their areas.

You can access Coral Reef Watch’s alert level here.