The coral Around the world they lose their color on an unprecedented scale as a result of increasing sea temperature, scientists have said this week, with 84% of reefs now in danger in the near future.

The huge blow to the marine habitats mentioned by the National Ocean and atmosphere National Service – The highest percentage ever recorded – comes as the planet experiences the fourth global coral boiling event, which occurs when bleaching is confirmed in every ocean basin at the same time.

OR Noaa He says that the last world event began on January 1, 2023 and has now observed mass whitening in at least 83 countries and territories, threatening marine life from Fiji to Florida keys and up to Great Barrier Reef of Australia.

“The ongoing global coral bleaching event is the largest to date,” said Noaa scientists.

The bleaching occurs when heat overturns the metabolism of the coral, resulting in white as it drives the symbiotic algae that provides it with nutrients and color. Whitening does not mean that the coral has died, but prolonged whitening – which scientists say it becomes more common and severe than rising sea temperatures – can kill it.

“Bleaching becomes more serious if the thermal stress episodes are more intense or if they last for a longer period,” said Joerg Wiedenmann, a marine biologist who runs the laboratory Coral Reef at the University of Southampton in England.

The growing Earth’s increasing temperatures have caused the most frequent appearance of bleaching phenomena and their longer duration, “he said. Changing and mixing ocean currents can also affect peripheral water temperatures, he added, further increasing the risk of bleaching.

Since the early 1980s, scientists say, coral whitening events have increased in frequency and seriousness, as the burning of fossil fuels raises the temperature of the planet. Noaa recorded the first world -class coral whitening event in 1998 and the second in 2010. During the previous world event, between 2014 and 2017, 68% of the world’s coral reefs suffered thermal stress at whitening level.

Mass whitening often coincides with episodes of El Ninium. This happened in 1998, 2016 and again last year, which was the warmest year recorded.

The oceans have consistently absorb rising temperatures for years, but in 2023 and 2024, temperatures broke a record. The seas also become more acidic as they are heated, which can dissolve the skeletons of the corals and make it difficult to grow.

In 2023, a sea wave off the coast off Florida It caused dramatic bleaching in parts of the unique living coral reef of the continental United States, impressing the experts with its rapid appearance. High temperatures made the coral tissue melt from its skeleton so fast that the color didn’t even have the opportunity to drain.

The bleaching was also so devastating that it prompted NOAA scientists to introduce a new bleaching warning scale – adding three categories to take into account the higher rates of coral mortality and bleaching levels. The new scale extends from Level 1, which means significant bleaching, at level 5 – five times the level of level 1 – which means that the coral is approaching mortality.

Last year, a deadly heat wave hit southern parts of the large 1,400 miles of Australia. In 2016, a mass whitening struck 93% of the reef, killing almost 50% of corals.

In addition to the loss of a flourishing underwater ecosystem, the death of corals can degrade reef structure and leave coastal communities vulnerable to flood risks, according to the US Geological Survey. In Florida, for example, coral reefs act as a natural regulator in the energy of storms that can protect the coasts from catastrophic forces.

According to Wiedenmann, coral reefs support one -third of marine biodiversity either directly or indirectly. “If corals die, this support structure that provides food and houses is lost. Consequently, many species will also suffer, “he said. According to a 2020 study, an increase in sea surface temperature and acidic waters could eliminate almost all surviving habitats of coral reefs by 2100.

However, Wiedenmann said, he is durable, offering some reason for hope. “The ancestors of today’s corals survived as an asteroid that eliminated the dinosaurs on land and many creatures at sea. So, if we manage to reduce ocean overheating, there is always the chance that corals will recover. “