In an alarming revelation, recent research indicates that 77% of the world’s coral reefs are now affected by bleaching, primarily driven by warming ocean waters linked to human-induced climate change. This extensive bleaching event, the fourth and most widespread on record, is impacting coral ecosystems across both hemispheres, according to the United Nations Capital Development Fund (UNCDF).
The findings prompted an urgent response, leading to an unprecedented emergency session on coral reefs convened on Wednesday during the final days of the U.N. biodiversity summit, COP16, held in Cali, Colombia. Such sessions are typically reserved for addressing sudden crises like natural disasters or escalating conflicts, underscoring the gravity of the situation.
Margaux Monfared, international policy and advocacy manager at the International Coral Reef Initiative, emphasized the dire stakes in a press conference on Tuesday. “We stand at a critical juncture. The evidence is undeniable,” Monfared stated. “Immediate, decisive action is necessary to confront the threats to the world’s coral reefs to prevent functional collapse.”
Coral reefs are essential to global biodiversity, sustaining over 25% of marine species and providing critical resources such as food, coastal protection, and economic stability for nearly a billion people worldwide. Yet, these ecosystems are particularly vulnerable to rising temperatures. A shift of just a few degrees can cause coral to expel the algae that provide their color and nutrients, leading to a weakened state known as bleaching. While other factors like low tides, pollution, and excessive sunlight can contribute, warming seas are the primary driver of the current crisis.
Notably, Australia’s Great Barrier Reef, the world’s largest coral reef system, has already seen 90% of its coral impacted by bleaching as of 2022. Florida’s Coral Reef, the third-largest globally, also experienced significant bleaching last year, highlighting the crisis’s reach across diverse geographies.
Following the emergency session, governments from New Zealand, the United Kingdom, Germany, and France committed an additional $30 million to the U.N. Coral Reef Fund, launched in 2020 to address coral conservation. With an ambitious target to mobilize up to $3 billion in public and private funding by 2030, the fund has so far raised $225 million. As an early step toward broader engagement, nations are encouraged to pledge an additional $150 million by next year’s U.N. Ocean Conference, set to take place in Nice, France.
The scale of coral bleaching reflects a mounting threat to marine biodiversity and human communities that depend on coral ecosystems. With global temperatures rising, Monfared and other experts are calling for urgent intervention and an immediate upscaling of funding to mitigate and reverse coral loss before it’s too late.