The largest global coral bleaching event ever recorded: US agency October 18, 2024

Coral bleaching - like the one seen here around Lizard Island on Australia's Great Barrier Reef - happens when the water is too warm (DAVID GRAY) (DAVID GRAY/AFP/AFP)

By AFP - Agence France Presse

The largest global coral bleaching event ever recorded: US agency

A global coral bleaching event that began last year has grown rapidly to become the largest ever recorded, according to a US agency, with the area of reefs affected continuing to grow.

From the beginning of 2023 until October 10, 2024, “about 77 percent of the world's reef area has experienced bleaching-level thermal stress,” Derek Manzello of the National Oceanic and Atmospheric Administration (NOAA) told AFP on Friday.

He said the current bleaching event - the fourth since 1998 - surpassed the previous record of 65.7% in half the time and “is still increasing in size.”

Corals are marine invertebrates made up of individual animals called polyps.

They have a symbiotic relationship with the algae that live inside their tissues and provide their main source of food, as well as their captivating colors.

When the water is too warm, as during the heatwaves that hit areas from Florida to Australia last year, the corals expel their algae and turn white, an effect called “bleaching” that leaves them exposed to disease and at risk of dying.

The last record was set during the third global bleaching event, which lasted from 2014 to 2017 and followed previous events in 1998 and 2010.

NOAA's heat stress monitoring is based on satellite measurements from 1985 to the present.

Manzello said that NOAA had confirmed reports of mass coral bleaching from 74 countries or territories since February 2023.

“This includes locations in the northern and southern hemispheres of the Atlantic, Pacific, and Indian Oceans,” he told AFP by email.

Around 850 million people around the world depend on coral reefs for food jobs and to protect coastlines from storms and erosion, according to the non-profit organization WWF.

The ecosystems provide a haven for ocean life, with more than a quarter of marine species calling them home.

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