fourth Global Coral Bleaching Event

NOAA and ICRI Confirm Fourth Global Coral Bleaching Event

MOMBASA, KENYA (Monday 15th April 2024) – The National Oceanic and Atmospheric Administration (NOAA) and the International Coral Reef Initiative’s (ICRI) global network of coral reef scientists have announced that the world is currently experiencing its fourth global coral bleaching event, the second in the last 10 years. Full press release available here. 

Bleaching-level heat stress, caused by prolonged increases in anomalous ocean temperatures, as remotely monitored and predicted by NOAA’s Coral Reef Watch (CRW), has – and continues to be – extensive across the Atlantic, Pacific, and Indian Oceans. 

Mass bleaching of coral reefs since mid-2023, has been confirmed in at least 53 countries and territories, including Florida (U.S.A), the Caribbean, the Eastern Tropical Pacific (including Mexico, El Salvador, Costa Rica, Panama, and Colombia), Australia’s Great Barrier Reef, large areas of the South Pacific (including Fiji, Vanuatu, Tuvalu, Kiribati, and the Samoas), the Red Sea (including the Gulf of Aqaba), the Persian Gulf, and the Gulf of Aden. 

A global mass bleaching event is declared when widespread bleaching is confirmed within all three major ocean basins—Atlantic, Pacific, and Indian Oceans. As the Western Indian Ocean regional coordinator for the Global Coral Reef Monitoring Network (GCRMN), an operational network of ICRI, CORDIO East Africa and regional partners have reported widespread bleaching in the region since early 2024. Observations in the WIO have been confirmed from Kenya, Tanzania, Comoros, Seychelles, Mauritius, and Reunion. 

“With record temperatures across oceans and continents since April 2023 and continuing into 2024, the current spread of bleaching across our region is not a surprise. That this has become the fourth global bleaching event should reaffirm to decision-makers that global warming must be halted as a priority for all nations and people, to limit further loss of coral reefs, other ecosystems and human suffering across the planet” – Dr. David Obura, IPBES Chair and Director of CORDIO East Africa.

Among bleaching observations from Kenya and Tanzania, March and April, 2024. 

The bleaching data collected by CORDIO East Africa and its partners is crucial for understanding the scale and specifics of the impact within the Western Indian Ocean as well as confirming the global bleaching event. 

While widespread coral bleaching can signal potential threats to economies, livelihoods, food security, and more, it is important to note that bleaching does not inevitably lead to coral death. If conditions improve and stressors diminish, bleached corals can recover, maintaining the crucial ecosystem services that reefs provide and ensuring no lasting loss in biodiversity or reef health. Economic losses and biodiversity declines are primarily felt when bleaching results in significant coral mortality, and when recovery of reefs is prevented by local conditions and/or further warming. 

“It is very important during this time to escalate bleaching awareness among coral reef stakeholders, in particular local communities. Minimizing stressors such as overfishing, water pollution and tourist activity can go far in facilitating recovery ” – Swaleh Aboud, Coral Reef Scientist, CORDIO East Africa. 

What is Coral Bleaching?


Climate services indicate a shift from El Niño towards neutral conditions, with a potential transition to La Niña by mid-2024. This change could cool equatorial Pacific waters, easing heat stress on corals. Additionally, a predicted negative phase of the Indian Ocean Dipole could lead to cooler waters in the Western Indian Ocean region, potentially providing a crucial recovery period. 

This global event requires global action. The International Coral Reef Initiative (ICRI), a partnership of 101 international members, currently chaired by the United States of America, is promoting resilience-based management actions for coral reefs. In response to the three previous global bleaching events as well as regional and local events, ICRI and its members have advanced coral interventions and restoration in the face of climate change. ICRI develops, and shares, best practices for the effective management of coral reefs through the implementation of its Plan of Action.

The ongoing global coral bleaching event serves as a critical indicator of the need for global and regional cooperation in managing coral reef ecosystems. CORDIO East Africa continues to work closely with regional and global partners for coral reef monitoring and conservation, advocating for protective measures and increased public awareness and engagement.

Global bleaching events do not affect all coral reefs equally and require a suite of global, regional, and local interventions. This emphasizes the importance of regularly monitoring coral reef ecosystems and not just during bleaching events. Networks such as the Global Coral Reef Monitoring Network (GCRMN), organized through regional networks such as in the Western Indian Ocean provide mechanisms for reporting on the impact of bleaching on the world’s coral reefs.

To share key messages and resources about coral bleaching, its impacts, causes and solutions currently being implemented and developed, ICRI has developed the “Coral Bleaching Hub”. Additionally, materials and guidance on responding to coral bleaching and mortality, and reporting observations that are fed through to the global ICRI network, can be found on the CORDIO East Africa’s, Indian Ocean Coral Bleaching website. 

ICRI will be hosting a webinar on Tuesday 14th May 2024 to present and discuss the current status of the 4th Global Bleaching Event, and the role of the global coral reef community. Register for the webinar here.

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Media Contacts

Dr. David Obura, – Director, CORDIO East Africa

Timothy Allela, – Communications Manager, CORDIO East Africa