| A. Coral reefs are threatened well beyond coastal areas. B. It won't happen immediately but it will be death by 1,000 blows. C. The reefs are likely to be among the first ecosystems to be wiped out by the climate crisis. D. It upgraded risk assessments for coral reefs following faster-than-expected global bleaching. E. The consequences include more than losing one of the most beautiful and bio-diverse habitats on the planet. F. Most available evidence suggests that coral dominated ecosystems will be non-existent at this temperature or higher. |
Children born today may be the last generation to see coral reefs in all their glory. That's a warning from a marine biologist who is coordinating efforts to monitor the decline of the world's most colorful ecosystem.
Global heating and ocean acidification(酸化) have already taken a heavy toll on the world's coral reefs. Some 16 to 33 percent of all warm-water reefs have been severely bleached(漂白), and the remaining reefs are vulnerable to even a fraction of a degree more warming, said the marine biologist, David Obura. He chairs the Coral Specialist Group in the International Union for the Conservation of Nature.
"It will be like lots of lights blinking off," he told the Observer. " Between now and 2 degrees Celsius, we will see more reefs dropping off the map."
Today's reefs have a history going back 25 million to 50 million years. They have survived collisions between the Earth's tectonic plates(地壳板块), such as that of Africa into Europe, and India into Asia. Yet in five decades, Obura said, mankind has undermined the global climate so fundamentally that the globally connected reef system could be lost in the next generation.
The warning follows a landmark UN climate report. Scientists warned that if warming reached 2℃, which now appears very likely in the next 50 years, there would be a more than 99% chance that tropical coral reefs would be wiped out.
The UN report also warned of severe knock-on impacts to fisheries and millions of people living in coastal communities, who will lose vital sources of income and be less protected from storms.
Coral reefs are often described as undersea forests, but they are declining far more quickly than the Amazon rainforests. A temperature rise of just 1 to 2 degrees Celsius can cause the algae(藻类) upon which corals(珊瑚虫) depend to leave. That would drain the coral reefs of colour and make the structure more easily broken. These bleaching events can be temporary if waters cool, but the more frequent they are and the longer they last, the greater the risk of irreparable damage.
