The world’s coral reefs are running out of time to recover between increasingly frequent marine heatwaves and global bleaching events, driven by human-induced climate change, a new global study – the ‘Status of Coral Reefs of the World: 2025’ said on Monday. Overall, a 9.5% relative decline in hard coral cover has been observed when comparing modern averages (2020–2024) with the reference period (1980–2009), it said.
Released by the Global Coral Reef Monitoring Network (GCRMN), the report which looked at more than 40 years of global data, said every major global bleaching event since 1998 has driven a sharp decline in global hard coral cover, creating a “staircase of decline” as recovery windows shrink.
The study further adds while recovery is still possible after a bleaching event, the window for recovery is shrinking. During the first global coral bleaching event between 1998 and 1999), there was a roughly 6.5% decline in hard coral cover . The second global coral bleaching event (2010–2011) led to a rough 9.9% decline; the third global coral bleaching event (2016–2017) led to a 6.6% decline and the latest and fourth global coral bleaching event (2023–2024) has led to a 8.9% decline, the study says. Recovery intervals have shrunk from approximately 10 years to 5–6 years in many regions, with no return to reference-period cover at any point since 2010, it noted. There was a 6% relative recovery in global hard coral cover following the third global bleaching event, it adds.
The study flagged four major global coral bleaching events in total, each of which led to a substantial drop in hard coral cover, with the reefs only partially recovering before the next marine heatwave strikes.
“GCRMN’s long-term monitoring tracks not just the pulse of coral reefs, but of our planet too. It shows which regions are under the greatest pressure, that actions to date have not been sufficient, and warns where reefs will be under increasing threat in years to come. We must act now to halt this decline and invest in solutions that reduce pressures and build resilience, while sustaining the monitoring that turns good intentions into effective policy,” he added.
