The next generation "will never see the glory of coral reefs" | Environment

Children born today may be the last generation to see coral reefs in all their splendor, according to a marine biologist who coordinates efforts to monitor the decline of the world's most colorful ecosystem.

Global warming and ocean acidification have already severely bleached 16 to 33 percent of all warm-water reefs, but the rest is vulnerable to even more modest warming, said David Obura, group president. of Coral Specialists from the International Union for the Conservation of Nature.

"It will be as if a lot of lights are going out," he told the Observer. "It will not happen immediately but it will be death by 1,000 strokes. Between now and 2 degrees Celsius, we will see more reefs fall off the map. "

Obura added, "The children born today are perhaps the last generation to see the coral reefs in all their splendor. Today's reefs have a history that goes back 25 to 50 million years and have survived tectonic collisions, such as that of Africa in Europe and India in Asia. Yet in five decades, we have undermined the global climate so fundamentally that we are going to lose the world-connected reef system, which has survived for tens of millions of years. "

This warning follows a UN climate report that has improved coral risk assessments after global bleaching faster than expected. Scientists from the Intergovernmental Panel on Climate Change (IPCC) have warned that if warming reaches 2 ° C, most likely in the next 50 years, the risk of eradicating tropical corals would be over 99%.

"Most of the available evidence suggests that coral-dominated ecosystems will be non-existent at this temperature or higher," said the IPCC study, which was endorsed by the 195 member countries of the UN the month latest.

In addition to losing one of the world's most beautiful and biodiverse habitats, the UN report warned of serious repercussions on the fishery and millions of people living in the wild. coastal communities, which will lose vital livelihoods and be less protected from storms.

Corals are often described as underwater forests, but their decline is much faster than the Amazon. With Arctic landscapes and high mountains, reefs – which have evolved over hundreds of millions of years – will likely be one of the first ecosystems to be wiped out by the climate crisis. A temperature rise of only 1 to 2 ° C can trigger an evacuation of the algae on which the corals depend, which drains them of color and makes the structure more fragile. These bleaching episodes can be temporary if the waters cool down, but the more frequent and long lasting they are, the greater the risk of irreparable damage.

But that's exactly what's happening. Whitening was first observed in 1983. It was observed globally in 1998, then in 2010, and then for three consecutive years from 2015 to 2017.

"The episodes of coral bleaching are becoming so severe and so frequent on the planet that reef systems are fragmenting into isolated pockets," Obura said. "Some of them will undoubtedly survive this century, but the highest scientific evidence tells us that, if we do not do everything in our power to limit warming to 1.5 ° C, we let's lose 99% of coral reefs in the coming decades. "

Eleven of the 29 World Heritage reefs have already undergone bleaching. UNESCO anticipates, according to current trends, that this number will increase to 25 by 2040.

More broadly, the reefs off Saudi Arabia, Madagascar, Hawaii and Papua New Guinea are likely to suffer bleaching well before the world average of 2043. Those with a perspective Larger – though thin – survival risks Egypt, Australia (including the Great Barrier Reef), Cuba, Indonesia and the Philippines.

But there are other threats than warming and acidity. Off the Philippine island of Palawan, pristine reefs have been severely damaged by sewage from tourist centers, pollution from boats and reckless fishing, including cyanide pumping into the coral structure to stun the fish that float, gather and gather. off for aquariums at the Chinese house.

According to Vince Cinches, Greenpeace Southeast Asia's Oceans Campaigner, it is disastrous for this to happen in the Coral Triangle, which should be a safe haven because it is one of the most ocean regions most resistant to climate change. "Even in the Philippines, we are losing our coral fast," he said. "We need to reduce the stress caused by overfishing, coastal development, pollution, mining, tourism and climate change."

Although some environmentalists are putting their lives at risk to avoid this, economic pressures continue to grow and corals' chances of survival are slim. The IPCC report noted that even if temperatures were maintained at 1.5 ° C, between 70% and 90% of the reefs would be lost.

Some of the more than 800 coral species have already been declared extinct, but as long as major reef builders continue to exist, it is unlikely that these complex systems can be rebuilt if temperatures stabilize.

Scientists like Obura are turning more and more to advocacy rather than to observation, but they claim that the last great function of corals could be to teach humanity to be better concerned about Other ecosystems.

"I am a generation of scientists watching them disappear. It's very depressing, "he said. "Above 1.5 ° C, in about 50 years, they will be legendary ecosystems, with beautiful virtual recreations and a treasure trove of historical and fantastic films and images, but very little to see in the real life."

"We are trying to do more than record the decline by making militant statements. We must convey the message that we must prevent this from happening for other ecosystems. That's what motivates me. If we do not take this lesson to limit global warming, we will have a lot more impact. "