Saturday, May 25, 2024

NOAA and ICRI Confirm Fourth Global Coral Bleaching Event


The world is currently experiencing its fourth global coral bleaching event, the second in the last 10 years, scientists announced this week.

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

According to NOAA CRW coordinator Derek Manzello:

“From February 2023 to April 2024, significant coral bleaching has been documented in both the Northern and Southern Hemispheres of each major ocean basin.”

Mass bleaching of coral reefs, since early 2023, has been confirmed in at least 53 countries, territories, and local economies, including the US state of Florida, 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.

Bleaching must be confirmed within each Ocean basin to make a final determination of a global bleaching event, according to NOAA and the International Coral Reef Initiative. Reports have now been confirmed of widespread bleaching across parts of the Western Indian Ocean, including Tanzania, Kenya, Mauritius, the Seychelles, Tromelin, Mayotte and off the western coast of Indonesia.

Manzello said:

“As the world’s oceans continue to warm, coral bleaching is becoming more frequent and severe. When these events are sufficiently severe or prolonged, they can cause coral mortality, which can negatively impact the goods and services coral reefs provide that people depend on for their livelihoods.”

Where coral bleaching results in mortality, especially on a widespread scale, it impacts economies, livelihoods, food security and more. However, it’s important to remember that coral bleaching does not always lead to coral death, according to a NOAA and ICRI joint statement. Rather, if the stress driving the bleaching diminishes, corals can recover, with reefs maintaining their biodiversity and continuing to provide the ecosystem services that we rely on.

Coral Bleaching and Recovery (Image credit: NOAA)
Coral Bleaching and Recovery (Image credit: NOAA)

Jennifer Koss, director of NOAA’s Coral Reef Conservation Program (CRCP), said:

“Climate model predictions for coral reefs have been suggesting, for years, that bleaching impacts would increase in frequency and magnitude as the oceans warm.”

ICRI is a partnership of 101 international members, currently co-chaired by NOAA and the US Department of State. 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.

NOAA has incorporated resilience-based management practices, increasing the emphasis on coral restoration, into its 2018 strategic plan, and funded a National Academies of Sciences study, leading to the publication of the 2019 Interventions to Increase the Resilience of Coral Reefs.

Koss added:

“We are on the frontlines of coral reef research, management and restoration, and are actively and aggressively implementing the recommendations of the 2019 Interventions Report.”

John Liang
John Liang
John Liang is the News Editor at He first got the diving bug while in High School in Cairo, Egypt, where he earned his PADI Open Water Diver certification in the Red Sea off the Sinai Peninsula. Since then, John has dived in a volcanic lake in Guatemala, among white-tipped sharks off the Pacific Coast of Costa Rica, and other places including a pool in Las Vegas helping to break the world record for the largest underwater press conference.