Latest news with #BrittaSchaffelke
Yahoo
23-04-2025
- Science
- Yahoo
Most of world's colourful corals go white in record-breaking bleaching
The world's rainbow reefs have gone ghostly white in seas around the globe. The "most intense global coral bleaching event ever" has so far struck 84 per cent of the world's reefs and is ongoing, the International Coral Reef Initiative (ICRI) — a global partnership between nations and non-governmental and international organizations focused on sustainable management of coral reefs — reported on Wednesday. The new figure is far worse than previous events that hit 21 to 68 per cent of reefs. But scientists say the reefs and the corals are not all dead yet and could still bounce back if people take the right steps, including conservation and cutting greenhouse gas emissions. Corals are small marine animals that live in colonies with colourful symbiotic algae that give them their rainbow hues and supply them with most of their food. But when the water gets too warm for too long, the algae release toxic compounds, and the corals expel them, leaving behind a white skeleton — causing "bleaching." The current global bleaching event, the fourth since 1998, started in January 2023, hitting different parts of the world at different times over the past two years, amid record-breaking ocean temperatures. It was officially declared a global coral bleaching event in April 2024. Last year, the Earth's hottest on record, the oceans also broke a record, hitting an average annual sea surface temperature of 20.87 C away from the poles. WATCH | Coral reefs experiencing mass bleaching event: No end in sight? The fact that it's ongoing two years later takes the world's reefs "into uncharted waters," Britta Schaffelke, a researcher with the Australian Institute of Marine Science and co-ordinator of the Global Coral Reef Monitoring Network, said in a statement accompanying ICRI's news release. "In the past, many coral reefs around the world were able to recover from severe events like bleaching or storms," she said. But the length of this bleaching event and the fact that it is getting longer by the day worries coral scientists. Mark Eakin, corresponding secretary of the International Coral Reef Society and retired chief of the Coral Reef Watch program of the U.S. National Oceanic and Atmospheric Administration, said it's an open question when — and even if — the current bleaching will end. "We may never see the heat stress that causes bleaching dropping below the threshold that triggers a global event," he told The Associated Press. WATCH | Coral reefs in Florida are hurting, but this may be the way to save them: Valeria Pizarro, a researcher with the non-profit Perry Institute for Marine Science who studies corals in the Caribbean, said bleaching used to sometimes happen at the end of summer, when the waters are at their warmest. But the current event started in her region in July, and temperatures are already 30 C to 32 C, when they're usually 28 C at this time of year. It has also damaged even very common species, she said, adding, "That is shocking." Nicola Smith, an assistant professor of biology at Montreal's Concordia University who also studies coral reefs in the Caribbean, noted that the Intergovernmental Panel on Climate Change has projected that coral reefs will decline 70 to 90 per cent if the global temperature warms to 1.5 C above pre-industrial temperatures. "We're seeing it play out before our eyes," she said. "This is what it's going to look like, not just in summer during bleaching, but year-round." Smith said the loss of coral reefs could harm many fish and other marine creatures. A report from the Intergovernmental Panel on Climate Change projected that if the world warms 1.5 C, there will be a 70 to 90 per cent decline in coral reefs. (CBC) "They provide literally thousands of other species with habitat as well as food, as well as shelter and sites for reproduction." The ICRI said not only does a third of marine life rely on coral reefs, but also a billion people — both directly and indirectly — for things like food, tourism and protection from storms. It estimates they contribute $10 trillion to the global economy. Not dead yet Still, the ICRI thinks corals can still survive this century if people take conservation measures and cut greenhouse gas emissions to slow ocean warming. And other scientists say despite the grim news, corals can often withstand and bounce back from bleaching. Melanie McField, founder and director of the Florida-based non-profit Healthy Reefs for Healthy People, said even without their food-supplying symbiotic algae, corals starve to death very slowly. "It ... takes months usually," she said. "They're kind of hanging on. Part of it is alive, it's partly dead." And even if the coral dies, other reef organisms such as sponges and crusty, pink coralline algae live on. WATCH | Our oceans are warming. What does that mean for the ecosystem?: "The Australians call it living dead. So you've still got a reef, you've still got some fish around," McField said. "Everything is kind of brown and grey." But the reef is vulnerable at that point, as sponges, worms and other creatures eat into the coral that is no longer rebuilding itself. "And then when that hurricane comes, it turns into rubble," McField said. She said that can be scary for people living on coasts protected by the coral reefs: "It's life and security." WATCH | Reef Rescue: Coral Atlas: The ICRI estimates that to save coral reefs and the people who rely on them, spending on solutions needs to increase sevenfold. Things that could help include selective breeding, coral restoration, reducing pollution and stopping overfishing. McField said that so far, a lot of those strategies are "very small little efforts at this time" and more of them are needed. Tiny fish hover over bleached corals in Ningaloo, Western Australia, in a February 2025 photo. Sponges and other marine creatures may still remain, and the corals may not be dead yet. (Daniel Nicholson/Ocean Image Bank) But keeping the global temperature as little above 1.5 C as possible is "necessary to give these coral conservation measures a chance to work," the ICRI said. McField agrees. "You can have all these efforts at 1.5 or 1.6 or 1.7, but probably not 2.... Don't go above that [or] I'm not sure we're going to be able to save them."
Yahoo
23-04-2025
- Science
- Yahoo
84% of world's coral reefs struck by worst bleaching event in history
April 23 (UPI) -- More than 80% of the world's coral reefs fell victim to harmful bleaching and is now in "uncharted territory" with the worst global bleaching event in recorded history. The coral reef system in at least 82 nations and other territories have been exposed to enough heart to turn at least 84% of the world's coral white since the global event started last year in January, according to data by the U.S. government's Coral Reef Watch. "Reefs have not encountered this before," said Dr. Britta Schaffelke of the Australian Institute of Marine Science and coordinator of the Global Coral Reef Monitoring Network, adding it was "unprecedented" and now the most intense event of its kind ever recorded. When water is too warm, coral will expel the algae -- otherwise known as zooxanthellae -- living in their tissues which causes the coral to turn completely white, according to the National Oceanic and Atmospheric Administration. During coral bleaching events, environmental stress like temperature change will trigger a breakup of the symbiotic relationship between coral and algae, which is now spreading like a wildfire to corals across the Pacific, Atlantic and Indian oceans and killing countless coral habitats. Otherwise known as the "rainforests of the sea," coral supports biodiversity and about a third of all marine species and at least a billion people. Although corals can recover from bleaching if temperatures are less extreme, past surveys have indicated a bleak picture of widespread global coral elimination. NOAA said last April that the world's oceans were undergoing the fourth global coral bleaching event on record and its second in the last 10 years as scientists in Florida, Mexico and the Caribbean raised alarm bells that summer over extreme bleaching in the northern hemisphere. Scientists further describe a "graveyard of dead corals" in Australia's northern Great Barrier Reef following 2024's bleaching event that caused about 40% of its coral life to die in one spot to its south. In Florida, where divers worked to save the Sunshine State's coral reefs, an average of one in five corals were lost and on Mexico's Pacific side, one area lost nearly 93% of its corals. But while warming water temps -- a result of climate change -- are a primary driver, newer research suggests that nitrogen pollution is the main cause of coral bleaching in Florida. Meanwhile, almost a quarter of corals were killed by heat last year in the middle of the Indian Ocean in the remote Chagos Islands. "Bleaching is always eerie -- as if a silent snowfall has descended on the reef," said Melanie McField, founder of the Caribbean-based Healthy Reefs for Health People initiative. "There is usually an absence of fluttering fish and an absence of the vibrant colors on the reef. It's an ashen pallor and stillness in what should be a rowdy vibrant reefscape." The report came as U.S. President Donald Trump has taken steps to boost fossil fuel production and a rollback of clean energy programs. "World leaders need to really commit to reduce fossil fuels and increase investments in clean energies and make it a reality," said Dr. Valeria Pizarro, a senior coral scientist at the Perry Institute for Marine Science working on reefs in the Bahamas and Caribbean Sea. The small island nation of Palau in the western Pacific experienced intense marine heatwaves in 1998, 2010 and 2017, but interestingly, each successive event led to less coral bleaching. However, scientific consensus is that ultimately the future of coral reefs will depend on a rapid reduction of carbon emissions which runs counter to Trump administration policy. "We need them to stop having it on paper and on the news, we need it to be real," Pizarro said.
The Guardian
23-04-2025
- Science
- The Guardian
More than 80% of the world's reefs hit by bleaching after worst global event on record
The world's coral reefs have been pushed into 'uncharted territory' by the worst global bleaching event on record that has now hit more than 80% of the planet's reefs, scientists have warned. Reefs in at least 82 countries and territories have been exposed to enough heat to turn corals white since the global event started in January 2023, the latest data from the US government's Coral Reef Watch shows. Coral reefs are known as the rainforests of the sea because of their high concentration of biodiversity that supports about a third of all marine species and a billion people. But record high ocean temperatures have spread like an underwater wildfire over corals across the Pacific, Atlantic and Indian oceans, damaging and killing countless corals. The 84% of reefs exposed to bleaching-level heat in this ongoing fourth event compares with 68% during the third event, which lasted from 2014 to 2017, 37% in 2010 and 21% in the first event in 1998. Even reefs considered by scientists to be refuges from the ocean's rising levels of heat have been bleached, Dr Derek Manzello, the director of Coral Reef Watch, said. 'The fact that so many reef areas have been impacted, including purported thermal refugia like Raja Ampat and the Gulf of Eilat, suggests that ocean warming has reached a level where there is no longer any safe harbour from coral bleaching and its ramifications,' he said. Many areas have seen bleaching in back-to-back years, including the world's biggest reef system, Australia's Great Barrier Reef, where last week authorities declared a sixth widespread bleaching event in just nine years. Australia's other World Heritage-listed reef along the Ningaloo coast in Western Australia has seen its highest levels of heat stress on record in recent months. Scientists on the other side of the Indian Ocean have reported bleaching in recent weeks affecting reefs off Madagascar and the east African coast, including South Africa's World Heritage iSimangaliso wetland park. Dr Britta Schaffelke, of the Australian Institute of Marine Science and coordinator of the Global Coral Reef Monitoring Network (GCRMN), said the event was unprecedented. 'Reefs have not encountered this before.' 'With the ongoing bleaching it's almost overwhelming the capacity of people to do the monitoring they need to do,' she said. 'The fact that this most recent, global-scale coral bleaching event is still ongoing takes the world's reefs into uncharted waters. '[For] people who spend their entire working lives on monitoring and observing reefs and protecting reefs, and living alongside them and relying on them, seeing something like this must be devastating. 'Ecological grief is real. People who spend a lot of time under the water see it changing before their eyes,' she said. The GCRMN is collating monitoring data for a status report due out next year, but Schaffelke said even that report would not give a full picture of the impact of the event. Scientists in north and central America, including Florida, the Caribbean and Mexico, were among the first to raise the alarm after record ocean temperatures saw extreme bleaching in the northern hemisphere's summer of 2023. Corals can recover from bleaching if temperatures are not too extreme, but surveys done in the months after the event have begun to paint a picture of widespread coral death. Sign up to Down to Earth The planet's most important stories. Get all the week's environment news - the good, the bad and the essential after newsletter promotion Across Florida, an average of one in five corals were lost. On the Pacific side of Mexico, one area lost between 50% and 93% of its corals. Almost a quarter of corals were killed by heat last year in the remote Chagos Islands in the middle of the Indian Ocean. Scientists described a 'graveyard of dead corals' in the northern section of the Great Barrier Reef after bleaching in early 2024 that caused 40% of corals to die in one area in the south. After the extreme heat of 2023, Coral Reef Watch was forced to add three new threat levels to its global bleaching alert system to represent the unprecedented heat stress corals had faced. Melanie McField, the founder of the Healthy Reefs for Healthy People initiative in the Caribbean, said reefs had fallen quiet across the world. 'Bleaching is always eerie – as if a silent snowfall has descended on the reef … there is usually an absence of fluttering fish and an absence of the vibrant colours on the reef,' she said. 'It's an ashen pallor and stillness in what should be a rowdy vibrant reefscape.' Dr Lorenzo Álvarez-Filip, a coral scientist at the National Autonomous University of Mexico, has been surveying reefs across the Mexican Caribbean and the Gulf of Mexico after the bleaching in 2023 and again in 2024. He said the most devastating impact was the loss of reef-building corals, such as elkhorns, that help protect coastlines and support a multitude of other marine life. 'Many of the coral colonies I knew well, and which had survived [a major disease] outbreak just a few years earlier, died in a matter of weeks. 'The feeling of impotence combined with the need to at least document what was happening made me very anxious – this was particularly hard when we were about to dive in sites where we knew there were big aggregations of susceptible corals. In almost all cases, we ended up with a very depressing feeling when we confirmed that all or nearly all the coral had died.' Dr Valeria Pizarro, a senior coral scientist at the Perry Institute for Marine Science that works on reefs in the Bahamas and Caribbean, witnessed extreme bleaching in the Bahamas in July 2023. She said 'in a blink of my eyes' shallow reefs became white landscapes, with widespread death among staghorn corals used in restoration projects. Spectacular sea fans and soft corals died quickly. 'It was like they were melting with the heat,' she said. 'World leaders need to really commit to reduce fossil fuels and increase investments in clean energies and make it a reality. We need them to stop having it on paper and on the news, we need it to be real.'
