Global coral bleaching event largest on record, reefs in 74 countries hit

The unprecedented scale of this bleaching event raises serious concerns about the long-term health and survival of coral reef ecosystems worldwide.

In Short

• This event has already exceeded the previous record by more than 11%
• Coral bleaching occurs when corals expel their symbiotic algae due to heat
• The current event has affected reefs in 74 countries and territories

The National Oceanic and Atmospheric Administration (NOAA) has confirmed that the ongoing global coral bleaching event, which began in February 2023, has become the most extensive on record.

An alarming 77% of the world's coral reef areas across the Atlantic, Pacific, and Indian oceans have experienced bleaching-level heat stress, surpassing previous records by a significant margin.

NOAA Coral Reef Watch coordinator Derek Manzello emphasized the severity of the situation, stating that this event has already exceeded the previous record by more than 11% in about half the time.

The unprecedented scale of this bleaching event raises serious concerns about the long-term health and survival of coral reef ecosystems worldwide.

Coral bleaching occurs when corals expel their symbiotic algae due to heat stress, leaving them vulnerable to starvation and disease. While bleached corals are not necessarily dead, their recovery depends on a rapid cooling of ocean temperatures.

The current event has affected reefs in 74 countries and territories, with recent confirmations in Palau, Guam, and Israel.

In response to this crisis, scientists have called for an emergency session on coral reefs at the upcoming United Nations Convention on Biological Diversity summit (COP16) in Colombia.

World leaders will discuss urgent strategies to prevent the functional extinction of corals, including enhanced protections and increased funding.

The severity of this bleaching event adds to growing evidence that coral reefs may have already crossed a critical tipping point.

Scientists had previously projected that up to 90% of reefs would be lost at 1.5°C of global warming, but the current situation suggests this threshold may have been reached at just 1.3°C.

The implications of this widespread bleaching are dire for ocean health, fisheries, and tourism.

Coral reefs provide an estimated $2.7 trillion in annual goods and services.

While the end of El Nino and the potential onset of La Nina may offer some relief, concerns remain that even cooler temperatures may not be enough to facilitate recovery if current ocean temperatures become the new normal.