A recent study analyzing samples taken from centuries-old coral has revealed the grave threat that climate change poses to the Great Barrier Reef. Researchers in Australia have found that temperatures in and around the vast coral reef over the past decade are the highest recorded in the last 400 years.
Extreme heat has already triggered five mass bleaching events across the Great Barrier Reef in the past nine years alone. The scientists behind this study, published in the journal Nature, conclude that the increased temperatures driven by climate change now pose an "existential threat" to this natural wonder of the world.
"The science tells us that the Great Barrier Reef is in danger - and we should be guided by the science," said Prof Helen McGregor from the University of Wollongong.
The new evidence comes directly from the coral itself. Marine scientists have collected core samples drilled from the coral skeletons, which provide chemical clues about how the surrounding environment has changed as the coral grew over the centuries. Since coral are long-lived animals, they lay down these chemical indicators about their natural environment over time.
By re-examining data from thousands of these coral cores and cross-referencing them with historical sea temperature records, the researchers were able to determine that the temperatures around the Great Barrier Reef in the previous decade were the warmest in the past 400 years. This underscores the unprecedented threat that climate change now poses to the future of this vital marine ecosystem.
"The recent events in the Great Barrier Reef are extraordinary," said Dr. Benjamin Henley, the lead researcher who carried out this study while working at the University of Wollongong. "Unfortunately, this is terrible news for the reef."
However, Dr. Henley added, "There is still a glimmer of hope though. If we can come together and restrict global warming, then there's a glimmer of hope for this reef, and others around the world, to survive in their current state."
Corals are adapted to survive and grow within a specific temperature range, forming a skeleton that provides a living habitat for other marine life. Corals exist in a symbiotic partnership with a special type of marine plant - a species of algae - which lives inside the coral, providing it with food and giving it its bright color.
Bleaching occurs when sea temperatures rise too high, causing corals to expel their algae and turn white. "It's not a pretty sight," said Dr. Henley. "Eventually, other algae grows on the surface of the white coral, turning it brown. While bleached coral can recover, if the heat does not relent, it doesn't have the chance to."
Prof. Helen McGregor, another researcher involved in the study, said, "I'm a little reluctant to say things are doomed. Reefs have survived a lot of change over geological time. So I guess the question comes down to - what kind of reef do we end up with? It won't be like what we have now."
The Great Barrier Reef is currently a UNESCO World Heritage site, and scientists hope this research could persuade the organization to change its status to "endangered." As Prof. McGregor explained, "That would send a huge signal to the world about how grave the problem is. We know what we need to do - we have international agreements in place [to limit global temperature rise]. I think we just need to put the politics aside and get on with it."
Reference: Victoria G. (7 Aug, 2024) Prolonged Record-Breaking Heat Poses Grave Threat to Great Barrier Reef
Retrieved from https://www.bbc.co.uk/news/articles/cy0ngx130kxo 400-year record heat threat to Great Barrier Reef
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