![\"Ove](\"https:\/\/ichef.bbci.co.uk\/news\/480\/cpsprodpb\/4c0c\/live\/f0e70df0-54b6-11ef-995b-4fa5edfe263b.jpg.webp\")
Ove Hoegh-Guldberg<\/span><\/div>\n<\/div>\nA study of samples taken from inside the bodies of centuries-old coral has revealed the threat climate change now poses to the Great Barrier Reef.<\/p>\n Researchers in Australia say temperatures in and around the vast coral reef over the past decade are the highest recorded in 400 years.<\/p>\n Extreme heat has already caused five mass bleaching events in the past nine years alone.<\/p>\n Writing in the journal Nature<\/a>, the scientists behind the study say increased temperatures, driven by climate change, now pose an \u201cexistential threat\u201d to this natural wonder of the world.<\/p>\n<\/div>\n \u201cThe science tells us that the Great Barrier Reef is in danger – and we should be guided by the science,\u201d Prof Helen McGregor, from the University of Wollongong, told BBC News.<\/p>\n The new evidence comes from within the coral itself.<\/p>\n Over many years, marine scientists have collected cores – samples drilled out of the skeletons of coral – which provide chemical clues about how the environment around the reef has changed as the coral developed.<\/p>\n Coral – which are animals, not plants – can live for centuries, laying down chemical indicators about their natural environment.<\/p>\n Researchers in Australia re-examined the data from thousands of these cores and cross-referenced them with historical sea temperature records from the UK\u2019s Hadley Centre. <\/p>\n The research showed temperatures around the Great Barrier Reef in the previous decade were the warmest of the past 400 years.<\/p>\n<\/div>\n “The recent events in the Great Barrier Reef are extraordinary,\u201d said lead researcher Dr Benjamin Henley, who carried out the study whilst working at Wollongong University.<\/p>\n \u201cUnfortunately, this is terrible news for the reef.”<\/p>\n \u201cThere is still a glimmer of hope though,” he added. “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.\u201d<\/p>\n Corals have adapted to survive and grow within a specific temperature range – forming a skeleton that provides a living habitat for other marine life. <\/p>\n 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 colour.<\/p>\n Bleaching occurs when sea temperatures rise too high and corals expel their algae, subsequently turning white.<\/p>\n \u201cIt\u2019s not a pretty sight,\u201d said Dr Henley. \u201cEventually [other] algae grows on the surface of the white coral, turning it brown.<\/p>\n “While bleached coral can recover, if the heat does not relent, it doesn\u2019t have the chance to,” he explained.<\/p>\n<\/div>\n \u201cI’m a little reluctant to say things are doomed,\u201d said Prof McGregor. <\/p>\n “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?<\/p>\n \u201cIt won’t be like what we have now.\u201d<\/p>\n![](\"https:\/\/www.bbc.com\/bbcx\/grey-placeholder.png\")
![\"Deb](\"https:\/\/ichef.bbci.co.uk\/news\/480\/cpsprodpb\/69c8\/live\/65982480-54b8-11ef-b2d2-cdb23d5d7c5b.jpg.webp\")
Deb Henley<\/span><\/div>\n<\/div>\n![\"Tane](\"https:\/\/ichef.bbci.co.uk\/news\/480\/cpsprodpb\/6417\/live\/df612a10-54b7-11ef-b39c-e325fe012747.jpg.webp\")
Tane Sinclair-Taylor<\/span><\/div>\n<\/div>\n‘Huge signal’<\/h2>\n<\/p>\n