This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Given enough time, coral reefs can recover from cyclones, bleaching and other destructive events. But a new report released today suggests they are losing that time.
The "Status of Coral Reefs of the World: 2025" is the most comprehensive global assessment of coral reefs yet. Released by the Global Coral Reef Monitoring Network (GCRMN), the report draws on more than 21 million observations from around 90,000 surveys, contributed by 600 partners across more than 120 countries, territories and economies. The findings show global hard coral cover has declined by 9.5% from an average of 30.2% during the historical reference period of 1980–2009 to 27.3% in 2020–2024.
Four global coral bleaching events, caused by climate-driven marine heat waves, were the main cause of the loss. "We have entered a time when disturbance is a regular feature of coral reefs," says UNSW Sydney's Associate Professor Tracy Ainsworth, a report coauthor and current vice president of the International Coral Reef Society. Major bleaching events previously occurred about once a decade.
Since 2010, they have occurred approximately every five to six years. But many corals need at least five years just to mature and begin reproducing. "In some places, severe disturbance is already happening annually.
In others, it is happening every few years," Ainsworth says. "The growth and maturity timeline that corals need is now being overwhelmed by stress and disturbance events." This means established corals can disappear faster than a new generation can grow and repopulate the reef. "The large corals we expect to see on reefs can be decades old," Ainsworth says.
"When they are lost, it takes decades for that population structure to return. "But that timeline is now interrupted by more, and increasingly severe, stress events, making it harder for new corals to grow and fill the reef." The report provides some evidence of reefs' resilience. Global hard coral cover increased by 6% from 2017 to 2019 following the third global bleaching event.
Extract — continue reading at the source.
