More than half of the world’s coral reefs were bleached between 2014-2017, a new study showed – a record-setting episode now being eclipsed by another series of devastating heatwaves.<\/p>\n
The analysis concluded that 51% of the world’s reefs endured moderate or worse bleaching while 15% experienced significant mortality over the three-year period known as the “Third Global Bleaching Event”.<\/p>\n
It was “by far the most severe and widespread coral bleaching event on record”, said Sean Connolly, one the study’s authors and a senior scientist at the Panama-based Smithsonian Tropical Research Institute.<\/p>\n
“And yet, reefs are currently experiencing an even more severe Fourth Event, which started in early 2023,” he said in a statement.<\/p>\n
When the sea overheats, corals eject the microscopic algae that provides their distinct colour and food source.<\/p>\n
Unless ocean temperatures return to more tolerable levels, bleached corals are unable to recover and eventually die of starvation.<\/p>\n
“Our findings demonstrate that the impacts of ocean warming on coral reefs are accelerating, with the near certainty that ongoing warming will cause large-scale, possibly irreversible, degradation of these essential ecosystems,” said the study in the journal Nature Communications.<\/p>\n
An international team of scientists analysed data from more than 15,000 in-water and aerial surveys of reefs around the world over the 2014-2017 period.<\/p>\n
They combined the data with satellite-based heat stress measurements and used statistical models to estimate how much bleaching occurred around the world.<\/p>\n
No time to recover<\/p>\n
The two previous global bleaching events, in 1998 and 2010, had lasted one year.<\/p>\n
“2014-17 was the first record of a global coral bleaching event lasting much beyond a single year,” the study said.<\/p>\n
“Ocean warming is increasing the frequency, extent, and severity of tropical-coral bleaching and mortality.”
Australia’s Great Barrier Reef, for instance, saw peak heat stress increase each year between 2014 and 2017.<\/p>\n
“We are seeing that reefs don’t have time to recover properly before the next bleaching event occurs,” said Scott Heron, professor of physics at James Cook University in Australia.<\/p>\n
A major scientific report last year warned that the world’s tropical coral reefs have likely reached a “tipping point” – a shift that could trigger massive and often permanent changes in the natural world.<\/p>\n
The global scientific consensus is that most coral reefs would perish at warming of 1.5C above preindustrial levels – the ambitious, long-term limit countries agreed to pursue under the 2015 Paris climate accord.<\/p>\n
Global temperatures exceeded 1.5C on average between 2023-2025, the European Union’s climate monitoring service, Copernicus, said last month.<\/p>\n
“We are only just beginning to analyse bleaching and mortality observations from the current bleaching event,” Sean Connolly said.<\/p>\n
“However the overall level of heat stress was extraordinarily high, especially in 2023-2024, comparable to or higher than what was observed in 2014-2017, at least in some regions,” he said.<\/p>\n
He said the Pacific coastline of Panama experienced “dramatically worse heat stress than they had ever experienced before, and we observed considerable coral mortality”.<\/p>\n","protected":false},"excerpt":{"rendered":"More than half of the world’s coral reefs were bleached between 2014-2017, a new study showed – a…\n","protected":false},"author":2,"featured_media":469384,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[49,48,295,66],"class_list":{"0":"post-469383","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-ca","9":"tag-canada","10":"tag-environment","11":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/469383","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=469383"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/469383\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/469384"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=469383"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=469383"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=469383"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}