The worldwood for corals is reached by new records – Liberation

Almost 84% of the planet’s reefs are now damaged. The massive episode of laundering corals in progress for two years continues to break records, threatening to kill these ecosystems essential to marine life and hundreds of millions of people who feed on fishing. Corals are very vulnerable to increase water temperatures. However, those of the globe oceans have been maintained since 2023 at unpublished levels, under the effect of global warming.

Consequence of this overheating and the acidification of the seas, caused by the greenhouse gas emissions of humanity, a world episode of whitening, the fourth since 1998, has been expanding for two years through the Atlantic, the Pacific and the Indian Ocean.

« Between January 1, 2023 and April 20, 2025, thermal stress synonymous with whitening affected 83.7 % of the planet reefs »announced the American ocean and atmospheric observation agency (NOAA) in its latest update published this Monday. In addition, several scientists, united by the International Initiative for Coral Reefs, alert this Wednesday, April 23 in a press release on the magnitude of the current episode.

The decline of the coral, manifested by its discoloration, is caused by an increase in the water temperature which causes the expulsion of its zooxanthelles – algae living in symbiosis with it – giving it its nutrients and its bright color. If high temperatures persist, coral can die.

The reefs can however recover if temperatures drop permanently or if other factors such as pollution or overfishing regress. But the temperatures noted in certain regions are extreme enough for « Enter a mortality of several species or quasi-total on a coral reef »explains the Noaa.

« The extent and extent of thermal stress are shocking »commented Melanie McField, founder in the Caribbean of the Healthy Reefs for Healthy People initiative, describing the whitening « Worrying » Who « Updated on the reef as a silent snowstorm »making the « Fish that are agitated and the bright colors ». « If the marine heat waves follow one another, it is difficult to see how the recovery will occur »alerts this scientist.

About a billion people worldwide live less than 100 km from these reefs and benefit, at least indirectly, from their presence. These « animal superorganisms » are home to huge fauna, bring millions of fishermen to life, attract a strong tourism activity but also protect the coasts from the damage of storms by serving as breakwards.

Nevertheless, 70 to 90 % of corals could disappear in a 1.5 ° C warmer planet than in the pre -industrial era, the climate expected by scientists in the early 2030s. It is even 99 % of corals which are threatened by global warming of 2 ° C, limit set by the Paris Agreement. For the time being, commitments to reduce carbon pollution in countries are taking the world to a warmed climate of 3.1 ° C at the end of the century, according to the UN.

« We must urgently put an end to the era of fossil fuels and operate a transition to a fair and lasting future, fueled by clean energies »urges SURANGEL Whipps Junior, president of the Petit Atoll in danger of Palau, in the Pacific.

« The link between fossil fuel emissions and the mortality of corals is direct and undeniable »abounded Alex Sen Gupta, from the University of New South Wales, in Australia. According to him, we must tackle the causes of evil but « Local measures such as reducing pollution, tourism management and control of parasitic epidemics can help strengthen resilience »he pleaded.

The year 2024 was the warmest ever measured on continents as on the surface of the oceans. And the rhythm of warming of the seas of the world has almost doubled since 2005, noted in September the European Observatory Copernicus. This warming is mainly explained by the fact that the oceans have absorbed since 1970 « More than 90 % of the excess heat of the climate system » Provided by greenhouse gases issued by humanity, according to the IPCC, climatologists mandated by the UN.