Global coral bleaching event expands, now the largest on record
Published: 06:10 PM,Oct 17,2024 | EDITED : 09:10 PM,Oct 17,2024
Bleached corals are seen in a reef in Koh Mak, Trat province, Thailand. — Reuters file photo
COPENHAGEN: The mass bleaching of coral reefs around the world since February 2023 is now the most extensive on record, the National Oceanic and Atmospheric Administration (NOAA) said this week.
A staggering 77 per cent of the world’s coral reef areas — from the Atlantic to the Pacific to the Indian oceans — have so far been subjected to bleaching-level heat stress, according to satellite data, as climate change fuels record and near-record ocean temperatures across the world.
'This event is still increasing in spatial extent and we’ve broken the previous record by more than 11 per cent in about half the amount of time,” said NOAA Coral Reef Watch coordinator Derek Manzello. 'This could potentially have serious ramifications for the ultimate response of these reefs to these bleaching events.”
The NOAA coral reef authority declared the global bleaching event in April 2024, making it the fourth of its kind since 1998. The previous record from the 2014 to 2017 mass bleaching affected just below 66 per cent of the world’s reef area.
Triggered by heat stress in warm oceans, coral bleaching occurs when corals expel the colourful algae living in their tissues. Without these helpful algae, the corals become pale and are vulnerable to starvation and disease. A bleached coral is not dead, but ocean temperatures need to cool off for any hope of recovery.
At least 14 per cent of the world’s remaining corals were estimated to have died in the previous two global bleaching events.
Though this mass bleaching is already the most widespread, affecting reefs in 74 countries and territories, NOAA has so far stopped short of calling, it the 'worst' on record. In coming months and years scientists will conduct underwater assessments of dead corals to help tally up the severity of the damage.
In just the last six weeks, bleaching has been confirmed in the waters of Palau, Guam and Israel. Heat stress also remains high in the Caribbean and South China Sea.
In response to the bleaching record, scientists have called a special emergency session on coral reefs to be held at the United Nations Convention on Biological Diversity summit (COP16) in Colombia at the end of the month. World leaders will discuss last-ditch strategies to avert the functional extinction of corals, including further protections and financing.
Scientists had previously projected that coral reefs would cross a tipping point at 1.5 degrees Celsius (2.7 F) of global warming, whereby up to 90% of reefs would be lost. The latest record bleaching adds to growing evidence that reefs have already passed a point of no return at just 1.3 C (2.3 F) of warming.
This would have dire implications for ocean health, subsistence fisheries and tourism. Every year, reefs provide about $2.7 trillion in goods and services, according to a 2020 estimate by the Global Coral Reef Monitoring Network. — Reuters
A staggering 77 per cent of the world’s coral reef areas — from the Atlantic to the Pacific to the Indian oceans — have so far been subjected to bleaching-level heat stress, according to satellite data, as climate change fuels record and near-record ocean temperatures across the world.
'This event is still increasing in spatial extent and we’ve broken the previous record by more than 11 per cent in about half the amount of time,” said NOAA Coral Reef Watch coordinator Derek Manzello. 'This could potentially have serious ramifications for the ultimate response of these reefs to these bleaching events.”
The NOAA coral reef authority declared the global bleaching event in April 2024, making it the fourth of its kind since 1998. The previous record from the 2014 to 2017 mass bleaching affected just below 66 per cent of the world’s reef area.
Triggered by heat stress in warm oceans, coral bleaching occurs when corals expel the colourful algae living in their tissues. Without these helpful algae, the corals become pale and are vulnerable to starvation and disease. A bleached coral is not dead, but ocean temperatures need to cool off for any hope of recovery.
At least 14 per cent of the world’s remaining corals were estimated to have died in the previous two global bleaching events.
Though this mass bleaching is already the most widespread, affecting reefs in 74 countries and territories, NOAA has so far stopped short of calling, it the 'worst' on record. In coming months and years scientists will conduct underwater assessments of dead corals to help tally up the severity of the damage.
In just the last six weeks, bleaching has been confirmed in the waters of Palau, Guam and Israel. Heat stress also remains high in the Caribbean and South China Sea.
In response to the bleaching record, scientists have called a special emergency session on coral reefs to be held at the United Nations Convention on Biological Diversity summit (COP16) in Colombia at the end of the month. World leaders will discuss last-ditch strategies to avert the functional extinction of corals, including further protections and financing.
Scientists had previously projected that coral reefs would cross a tipping point at 1.5 degrees Celsius (2.7 F) of global warming, whereby up to 90% of reefs would be lost. The latest record bleaching adds to growing evidence that reefs have already passed a point of no return at just 1.3 C (2.3 F) of warming.
This would have dire implications for ocean health, subsistence fisheries and tourism. Every year, reefs provide about $2.7 trillion in goods and services, according to a 2020 estimate by the Global Coral Reef Monitoring Network. — Reuters