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World sees 'severe' coral bleaching event — US agency

April 15, 2024

The NOAA scientific agency says that the world is experiencing its second bleaching event in 10 years. A coral reef off the coast of Florida has been impacted, as has Australia's Great Barrier Reef.

A photo of bleached coral reef at the Great Barrier Reef off Australia
The world's largest coral reef, the Great Barrier Reef off Australia, faces a bleaching threat amid global rising temperaturesImage: Grace Frank/Australian Institute of Marine Science/REUTERS

The US National Oceanic and Atmospheric Administration (NOAA) said in a reporton Monday that the world is experiencing a major coral bleaching event following months of record levels of heat in the oceans.

This is the second such event in 10 years, according to the agency. It is caused by warming oceans as part of climate change.

2023 was the hottest year on record.

What else did the agency say about bleeching?

"As the world's oceans continue to warm, coral bleaching is becoming more frequent and severe," NOAA'S Derek Manzello said.

"When these events are sufficiently severe or prolonged, they can cause coral mortality, which hurts the people who depend on the coral reefs for their livelihoods."

The agency's heat-stress monitoring is based on satellite measurements from 1985-2024.

The current bleaching event is the fourth on record. The last three events were in 1998, 2010 and 2016.

Bleaching occurs when coral expel their algae and turn white. Algae provide coral with their primary source of food.

Tackling coral-reef damage using the sounds of the sea

Where is the bleaching occurring?

Mass bleaching of coral reefs has been confirmed throughout the tropics since early 2023. It has been recorded in at least 53 countries or territories since February 2023.

NOAA said that a heatwave in the southeastern US state of Florida lasted longer and was more severe than any other recorded event in the region. Florida's coral reef is the third-largest in the world.

The world's largest coral reef, the Great Barrier Reef off the eastern coast of Australia, has also been affected by the bleaching event. Other corals experiencing bleaching are in the South Pacific, the Red Sea and the Persian Gulf.

"We know the biggest threat to coral reefs worldwide is climate change. The Great Barrier Reef is no exception," Australia's Environment Minister Tanya Plibersek said recently.

According to the WWF environmental NGO, around 850 million people rely on coral reefs for food, jobs and protection from storms and erosion.

sdi/wd (AFP, AP)