Rising Ocean Temperatures Sparking Unprecedented Global Coral Bleaching Crisis

Coral reefs worldwide are facing a significant bleaching event due to the increasing ocean temperatures caused by the climate crisis. Experts are concerned that this could potentially be the worst bleaching period ever recorded.

According to a joint statement from the National Oceanic and Atmospheric Administration (NOAA) and The International Coral Reef Initiative (ICRI), over 54% of coral reef areas globally have undergone bleaching in the last year. This has impacted at least 53 countries and territories, including vast areas of the Atlantic, Pacific, and Indian Oceans.

"It is expected that this event will soon exceed the previous peak of 56.1%, according to Derek Manzello, the coordinator for NOAA’s Coral Reef Watch program. The percentage of reef areas experiencing bleaching-level heat stress has been steadily increasing by about 1% per week," Manzello mentioned in an email to CNN.

When corals face stress from marine heatwaves, they expel the algae living in their tissue, which gives them their color and much of their energy. If ocean temperatures do not return to normal, bleaching can result in widespread coral mortality, posing a threat to the species and the food chains that depend on them.

This is the fourth global bleaching event that has occurred in the world, and the second one in the last ten years. Previous events took place in 1998, 2010, and between 2014-2017.

In the past year, mass bleaching has been observed in various regions such as Florida, 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 and the Seychelles.

French Polynesia is home to the stunning Society Islands, where coral reefs are a sight to behold. Recently, these reefs have been experiencing major bleaching, prompting marine biologist teams from CRIOBE to take action. Led by PhD Laetitia Hédouin, these specialists are focusing on identifying and studying "resilient corals" that are not affected by thermal stress. By conducting genetic analysis and growing coral cuttings in a "coral nursery", they aim to understand and enhance the resilience capacity of coral colonies in the region. (Photo by Alexis Rosenfeld/Getty Images)

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Ocean temperatures are currently at unprecedented levels, causing concern among scientists.

Professor Ove Hoegh-Guldberg, a climate scientist who focuses on coral reefs at the University of Queensland in Australia, had foreseen this widespread bleaching event months in advance.

"We were aware that sea temperatures were rising quickly, but the rate at which it's happening now is unexpected," Hoegh-Guldberg told CNN on Monday. "The concerning part is that we are unsure of how long this drastic temperature increase will continue."

The past year has seen the highest temperatures on record for the planet, with ocean temperatures skyrocketing beyond previous levels. Data from the European Commission’s Copernicus Climate Change Service shows that global sea surface temperatures reached record highs in February and then again in March.

In February, the Coral Reef Watch program at NOAA introduced three additional alert levels to the coral bleaching alert maps. This update will help scientists better evaluate the increasing levels of underwater warming.

Divers swim past bleached corals in the waters of Raja Ampat Regency in east Indonesia's West Papua region on November 5, 2023.

Divers swim past bleached corals in the waters of Raja Ampat Regency in east Indonesia's West Papua region on November 5, 2023.

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Could La Niña provide some relief?

El Niño, a natural climate pattern that starts in the Pacific Ocean near the equator and usually leads to higher global temperatures, has played a role in the record-breaking ocean heat.

NOAA's Manzello mentions that La Niña, the cooler counterpart of El Niño, is expected to arrive between June and August this year. This could bring some hope for coral reefs. However, it is important to note that bleaching events have still been observed during La Niña in recent years.

"I am getting more worried about the summer of 2024 for the wider Caribbean and Florida," Manzello expressed. "As we approach summer and the bleaching season for Florida and the Caribbean, it won't require much more warming to exceed the bleaching threshold."

A turtle swims over bleached coral in the lagoon of Lady Elliot Island on the southern Great Barrier Reef, on February 19 2024.

A turtle swims over bleached coral in the lagoon of Lady Elliot Island on the southern Great Barrier Reef, on February 19 2024.

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In mid-February, CNN observed widespread coral bleaching on Australia's Great Barrier Reef, the world's largest coral reef system, across five different reefs in the northern and southern regions. Last month, a significant bleaching event was officially confirmed following aerial and underwater surveys conducted by the Australian Institute of Marine Science (AIMS) and the Great Barrier Reef Marine Park Authority.

Selina Stead, the CEO of AIMS, highlighted that the increasing frequency and severity of marine heatwaves, caused by climate change, are pushing the limits of coral reef resilience. She emphasized that climate change poses the greatest threat to coral reefs globally, as evidenced by the widespread impact over the past year.

"It is crucial for the world to focus on lowering carbon emissions," Stead emphasized. "Equally important is the proper management of coral reefs at both local and regional levels."

File photo taken in October 2016 shows coral bleaching at the Great Barrier Reef in Australia, a World Heritage Site.

File photo taken in October 2016 shows coral bleaching at the Great Barrier Reef in Australia, a World Heritage Site.

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Australia’s Great Barrier Reef hit once more by mass coral bleaching

The UN Environment Programme has issued a warning about the consequences of not reducing emissions. If we do not take aggressive action, the planet could warm by nearly 3 degrees Celsius above pre-industrial levels this century.

Scientists have made predictions that are concerning. If the world reaches 2 degrees of warming, which could happen around 2050, it is estimated that about 99% of the world's coral reefs would die.

Coral reefs are not only important for marine life, but they also play a critical role in protecting coastal communities from flooding caused by storms and rising sea levels. Additionally, they provide livelihoods and a crucial food source for approximately one billion people worldwide.

According to David Ritter, CEO of Greenpeace Australia, coral reefs are in serious danger and the main responsibility lies with those contributing to global warming, such as fossil fuel companies and governments supporting this industry.

“We are running out of runway to avoid irreversible climate disaster,” he added, “and must act quickly to ensure an immediate end to new fossil fuels.”

Editor's P/S:

The article paints a dire picture of the current state of coral reefs worldwide, with the ongoing bleaching event threatening to be the worst on record. It is heartbreaking to witness these vibrant and diverse ecosystems, which support countless marine species and provide livelihoods for coastal communities, being pushed to the brink of collapse. As a concerned individual, I find it imperative to amplify awareness about this pressing issue and urge collective action to mitigate the impacts of climate change.

Efforts like those undertaken by marine biologist teams in French Polynesia offer a glimmer of hope by focusing on identifying and studying resilient corals that can withstand thermal stress. Such initiatives hold the potential to enhance the resilience of coral colonies and preserve these invaluable ecosystems for future generations. Moreover, it is crucial for governments and corporations to prioritize the reduction of carbon emissions and transition to renewable energy sources to mitigate the root cause of coral bleaching. The future of these underwater wonders and the well-being of our planet depend on our collective responsibility and commitment to safeguard them.