A mass bleaching event is occurring in coral reefs around the world as the climate crisis triggers record-breaking ocean heat, two science organizations announced Monday. some experts warn this could be the worst bleaching period in recorded history.
More than 54% of the world’s coral reef areas experienced bleaching last year, affecting at least 53 countries and territories, including large areas of the Atlantic, Pacific and Indian Oceans, according to a joint statement from the National Oceanic and Atmospheric Administration (NOAA). ) and the International Coral Reef Initiative (ICRI) said.
“This event is likely to surpass the previous peak of 56.1% soon,” Derek Manzello, coordinator of NOAA’s Coral Reef Watch program, said in an email to CNN. “The percentage of reef areas experiencing heat stress at the bleaching level is increasing by approximately 1% per week.”
When corals are exposed to stress from marine heat waves, they expel the algae living in their tissues, which provides them with both their color and much of their energy. If ocean temperatures do not return to normal, bleaching could cause mass coral death and threaten the species and food chains that depend on them with collapse.
This is the fourth global bleaching event in the world and the second in the last decade, with previous periods in 1998, 2010 and 2014-2017.
Last year, mass bleaching was confirmed in regions such as Florida and the wider Caribbean, Mexico, Brazil, Australia, the South Pacific, the Red Sea, the Persian Gulf, Indonesia and the Indian Ocean, including the east coast of Africa. Seychelles.
Professor Ove Hoegh-Guldberg, a climate scientist specializing in coral reefs at the University of Queensland in Australia, predicted this mass bleaching event months ago.
“We knew that sea temperatures were rising rapidly, but not at this rate,” Hoegh-Guldberg told CNN on Monday. “The worrying issue is that we don’t know how long this major temperature change will last.”
The last 12 months have been the planet’s warmest on record, and ocean temperatures have risen incredibly. Global sea surface temperatures reached record levels in February and March, according to data from the European Commission’s Copernicus Climate Change Service.
In February, scientists in the Coral Reef Monitoring program at NOAA added three new warning levels to coral bleaching warning maps to allow scientists to assess the new scale of underwater warming.
Will La Niña bring relief?
El Niño, a natural climate pattern that originates from the Pacific Ocean along the equator and tends to increase global temperatures, has helped increase unprecedented ocean temperatures.
NOAA is predicting that La Niña, El Niño’s colder counterpart, could arrive between June and August this year, providing “a glimmer of hope” for coral reefs, NOAA’s Manzello said.
But he added that La Niña bleaching events have still occurred in the last few years.
“I am increasingly concerned about summer 2024 for the broader Caribbean and Florida,” Manzello said. “Once we enter summer and bleaching season for Florida and the Caribbean, there will be no need for additional seasonal warming to raise temperatures above the bleaching threshold.”
In mid-February, CNN witnessed extensive coral bleaching at five different reefs spread across northern and southern regions of Australia’s Great Barrier Reef (the world’s largest coral reef system). A mass bleaching event was officially confirmed there last month following aerial and underwater surveys by the Australian Institute of Marine Science (AIMS) and the Great Barrier Reef Marine Park Authority.
“The increasing frequency and extremeness of marine heatwaves driven by climate change are testing the tolerance levels of coral reefs,” said AIMS CEO Selina Stead. “Climate change is the biggest threat to coral reefs worldwide and this global confirmation shows just how far-reaching its impact has been over the last 12 months.”
“That’s why it’s critical that the world works to reduce carbon emissions,” Stead added. “It is also important to ensure that coral reefs are well managed at the local and regional level.”
The UN Environment Program has warned that unless the world aggressively reduces its emissions, the planet is heading towards warming of around 3 degrees Celsius above pre-industrial levels this century.
Scientists estimate that even with 2 degrees of warming, which the world could reach around 2050, approximately 99% of corals on Earth would die.
In addition to being an important habitat for marine life, coral reefs are also vital to coastal communities around the world; It acts as a vital defense system against the threat of flooding from storms and sea level rise, and also provides livelihoods and a vital source of food. an estimated one billion people worldwide.
Greenpeace Australia CEO David Ritter said the reefs faced “existential danger” and that the blame lay with “the main culprits fueling global warming: fossil fuel companies and the governments that support this industry.”
“We are running out of runway to avoid an irreversible climate catastrophe,” he added, “and we must act quickly to ensure an immediate end to new fossil fuels.”
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