The world is experiencing the largest wave of coral bleaching — more than 80% of all reefs affected

As of 2023, 84% of coral reefs worldwide have suffered from bleaching. Due to global warming, scientists are unsure when it will end, or if it will end at all.

This is reported by The Washington Post.

When corals are exposed to high temperatures for too long, they lose their color and eventually die. The planet is currently experiencing the fourth global coral bleaching event, with at least 83 countries and territories affected, from Fiji to Florida and the Great Barrier Reef in Australia.

“This is the largest global coral bleaching event we have ever recorded,” says the US National Oceanic and Atmospheric Administration (NOAA).

Stress causes corals to expel the zooxanthellae that live in them and provide them with color and nutrients. As a result, the corals lose their color and turn white. Bleaching itself does not mean that the coral has died, but if the stress continues for a long time, the corals cannot withstand it. The longer the heating, the worse the consequences.

Coral bleaching has become more frequent since the 1980s. The reason is rising ocean temperatures due to climate change. Due to frequent bleaching, corals do not have time to recover, which leads to their gradual disappearance.

In 2023 and 2024, ocean temperatures reached record highs. This not only made the water hotter, but also more acidic, which is a threat to corals, as the acidity destroys their limestone skeletons and makes it difficult for them to grow. Corals are important not only for the marine ecosystem. Their death weakens the structure of reefs, making coastal areas more vulnerable to flooding. For example, in Florida, reefs act as natural protection against storms and waves.

According to scientist Joerg Wiedenmann, corals support a third of all marine life. If they disappear, so do species that depend on reefs for food and shelter. A 2020 study found that unless greenhouse gas emissions are reduced and climate change is halted, coral ecosystems will almost completely disappear by 2100.

But scientists are not giving up hope. As Wiedenmann notes, the ancestors of modern corals even survived the asteroid impact that wiped out the dinosaurs. If humanity can slow down the warming of the oceans, corals have a chance to recover.

• Coral reefs are among the oceanʼs most endangered ecosystems: they are vulnerable to pollution, rising sea temperatures, and changes in water chemistry caused by carbon dioxide emissions. Scientists predict that 70% to 90% of all living coral will disappear within the next 20 years. According to UNESCO, only about 20% of the ocean floor has been mapped to date.

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