Coral stress: temperature thresholds from 1982 to 2016
Heat stress – and likely bleaching and mortality – on the Great Barrier Reef over 34 years, prepared for the Guardian by Noaa's Coral Reef Watch. Heat stress is estimated based on satellite measurement of water temperature. Alert level one means bleaching is likely; alert level two means mortality is likely. Mass bleaching events in 1998, 2002 and 2016 are highlighted
Great Barrier Reef
No stress
Alert level one
Alert level two