Scientists said Monday that coral reefs face continuous bleaching episodes occurring so frequently that they no longer have adequate time to recover. The global coral cover has fallen well below its historical average and faces deterioration that will be difficult to reverse, they warned.
Coral reefs support roughly one-quarter of marine life worldwide and provide coastal protection, food and livelihoods for millions of people. Their survival is now threatened by pollution and accelerating coral bleaching caused by rising ocean temperatures.
The Global Coral Reef Monitoring Network, which analyzed data from more than 37,000 reef sites across 120 countries and territories over more than 40 years, found that intervals between bleaching episodes once spanned decades but now occur every five to six years. Manuel González Ribeiro, who led the study, said: "If corals are given sufficient time, they are capable of recovering. But we have not seen such time being given; in fact, the intensity of bleaching factors has roughly doubled."
Bleaching occurs when corals expel the colored algae living in their tissue; without these algae providing nutrition, corals lose color and become more vulnerable to starvation and disease. While bleached corals do not necessarily die, their recovery depends on ocean temperatures declining.
Hard coral cover declined 9.5 percent below its historical average between 2020 and 2024. González Ribeiro said: "Coral cover globally remained relatively stable over 40 years until 2010. Since then, there has been a very sharp change."
The report was released as Pacific leaders gathered in Palau on Monday for the annual Pacific Islands Forum, where they are expected to coordinate climate priorities before the United Nations climate conference in late 2025.
