The fourth global coral bleaching event may have concluded in the mid-2025, scientists have said.
As many as 83 countries and territories were impacted in all three coral reef housing ocean basins — Pacific, Atlantic and Indian Oceans.
Following the severe bleaching in Western Australia in early 2025, global heat stress has been in decline and there have been only isolated reports of coral bleaching.
The western Australia bleaching event likely bookended the fourth global event, the statement from NOAA said.
The Global Tipping Points Report 2025 noted that earth reached its first catastrophic tipping point - that is widespread bleaching and death of coral reefs.
The fourth global coral bleaching event may have concluded in the mid-2025, scientists have said.
Researchers from the National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch stated that after analysing satellite data and bleaching observations, the record-breaking event that was confirmed on April 15, 2024 concluded, causing 84 per cent bleaching-level heat stress.
As many as 83 countries and territories were impacted in all three coral reef housing ocean basins — Pacific, Atlantic and Indian Oceans.
Following the severe bleaching in Western Australia in early 2025, global heat stress has been in decline and there have been only isolated reports of coral bleaching.
The western Australia bleaching event likely bookended the fourth global event, the statement from NOAA said. “We needed to confirm that no widespread, large-scale bleaching was reported anywhere during the austral summer which ran from December 2025 through February 2026, before we were confident the event had ended,” said Derek Manzello, Coordinator of NOAA’s Coral Reef Watch in the statement.
“We are now in the era where reefs will bleach on a near-annual basis, which means defining when global events begin and end is becoming increasingly difficult. The plan moving forward is to rely on field bleaching observations to determine if and when global events are happening,” he added.
The Global Tipping Points Report 2025 noted that earth reached its first catastrophic tipping point - that is widespread bleaching and death of coral reefs.
The report stated that warm-water coral reefs, or shallow coral reefs in tropical and sub-tropical regions, are crossing their thermal tipping point and undergoing unprecedented die-off that threatens the livelihoods of almost one billion people who directly and indirectly depend on reefs for food, income and coastal protection.
