Report: Global coral cover falls 9.5% as reefs struggle to recover

The world's coral reefs are under increasing pressure, with recovery periods between mass bleaching events becoming shorter and coral cover declining, according to a report published on Monday.
Global hard coral cover has fallen by about 9.5% compared with the 1980-2009 average, according to the 'Status of Coral Reefs of the World: 2025' report by the Global Coral Reef Monitoring Network (GCRMN), presented in the Pacific island nation of Palau.
The assessment analysed more than 21 million observations from over 36,800 reef sites across 124 countries, territories and areas. Each of the four major global coral bleaching events since 1998, driven by marine heatwaves, was followed by a significant decline in hard coral cover.
The latest event in 2023-24 resulted in an 8.9% decline, compared with 6.5% in 1998-89, 9.9% in 2010-11 and 6.6% in 2016-17.
Coral bleaching occurs when corals lose the algae living in their tissues, leaving them weakened and pale. Climate change is the main driver of mass bleaching worldwide. Only if temperatures fall again in time can the corals take in new symbiotic algae and recover.
Scientists warned that reefs are increasingly running out of time to recover. Global hard coral cover increased by about 6% between 2017 and 2019, showing reefs can recover when given enough time, the report said.
But reefs that once had decades between severe bleaching events now often have only five to six years, said lead author Manuel González Rivero of the Australian Institute of Marine Science.
'This is creating a staircase of decline that becomes harder to reverse with every bleaching event,' González Rivero said. 'After decades of studying coral reefs, what concerns me most isn't the current loss of hard coral cover; It's that we're steadily eroding the conditions they need to recover.'
Coral reefs cover less than 0.2% of the ocean floor but provide habitat for at least a quarter of marine species and support food supplies, incomes, coastal protection and tourism.
The EU's Copernicus climate change service said just days ago that the world's oceans were at their warmest since records began in 1979.