Great Barrier Reef suffers biggest annual drop in live coral since 1980s after devastating coral bleaching
The Australian Institute of Marine Science (Aims) report is the first to comprehensively document the devastating impacts of the early 2024 mass coral bleaching event – the most widespread and severe on record for the Great Barrier Reef.
In the months that followed, scientists described a 'graveyard of corals' around Lizard Island in the north and a study recorded the death of 40% of corals at One Tree Island in the south.
Aims has conducted annual in-water surveys of the world's biggest reef system since 1986, checking the health and extent of corals.
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This year's survey report found that in the reef's northern section – between Cooktown and the tip of Cape York – bleaching, two cyclones and associated flooding had caused coral cover to fall by 25%.
In the southern section, from Mackay to just north of Bundaberg, coral cover had fallen by 30%. The northern and southern zones suffered the highest annual drops on record.
Coral cover fell by 13% in the central section, which had escaped the worst of the heat in 2024.
Dr Mike Emslie, who leads the long-term reef monitoring program at Aims, said coral cover was becoming more volatile. 'It has been a pretty sobering year of surveys with the biggest impacts I have seen in the 30-plus years I have been doing this,' he said.
'This volatility is very likely a sign of an unstable system. That's our real concern. We're starting to see record highs in coral cover that quickly get turned around to record falls.'
Coral bleaching describes a process whereby the coral animal expels the algae that live in its tissues and give it its colour and much of its nutrients.
Without its algae, a coral's white skeleton can be seen through its translucent flesh, giving off a bleached appearance.
Mass coral bleaching over large areas, first noticed in the 1980s around the Caribbean, is caused by rising ocean temperatures.
Some corals also display fluorescent colours under stress when they release a pigment that filters light. Sunlight also plays a role in triggering bleaching.
Corals can survive bleaching if temperatures are not too extreme or prolonged. But extreme marine heatwaves can kill corals outright.
Coral bleaching can also have sub-lethal effects, including increased susceptibility to disease and reduced rates of growth and reproduction.
Scientists say the gaps between bleaching events are becoming too short to allow reefs to recover.
Coral reefs are considered one of the planet's ecosystems most at risk from global heating. Reefs support fisheries that feed hundreds of millions of people, as well as supporting major tourism industries.
The world's biggest coral reef system – Australia's Great Barrier Reef – has suffered seven mass bleaching events since 1998, of which five were in the past decade.
With relatively benign impacts from cyclones and bleaching in the five years before the 2024 event, coral cover had reached record levels in some places.
But that recovery, Emslie said, was largely driven by fast-growing acropora corals that were more susceptible to heat stress.
'We had said it could all get turned around in one year and, low and behold, here we are,' he said, adding that coral cover was now mostly back in line with long-term averages.
The 2024 and 2025 events were part of an ongoing global mass coral bleaching event that led to more than 80% of the planet's reefs being hit with enough heat to cause bleaching, affecting corals in at least 82 countries and territories.
A study last year found ocean temperatures on the Great Barrier Reef were probably at their hottest for at least 400 years and were an 'existential threat' to the Unesco world heritage-listed reef.
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Widespread mass bleaching of the Great Barrier Reef was first seen in 1998 and happened again in 2002, 2016, 2017, 2020, 2022, 2024 and 2025.
'These impacts we are seeing are serious and substantial and the bleaching events are coming closer and closer together,' Emslie said.
'We will ultimately get to a tipping point where coral cover can't bounce back because disturbances come so quickly that there's no time left for recovery.
'We have to mitigate the root causes of the problem and reduce emissions and stabilise temperatures.'
The Aims report comes a month before the federal government is due to reveal its emissions reduction target for 2035.
The Albanese government promised Unesco last year it would 'set successively more ambitious emissions reduction targets' that would be 'in alignment with efforts to limit global temperature increase to 1.5C'.
Last week the Climate Change Authority, which will advise the government on what target to set, released a report that said holding warming 'as close as possible to 1.5C' was key to addressing the threats facing the reef.
Richard Leck, head of oceans at WWF Australia, said the government needed to set a target consistent with 1.5C.
'This is the one action the government can take to give the reef a fighting chance.'
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The Guardian
an hour ago
- The Guardian
Can an AI chatbot of Dr Karl change climate sceptics' minds? He's willing to give it a try
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After speaking with longtime friend and technology journalist Leigh Stark, the pair settled on an idea: an AI-powered Digital Dr Karl. Using a large language model (LLM), they're creating a chatbot designed to sound like Kruszelnicki that provides users with evidence, backed by trustworthy sources, that the climate crisis is caused by humans and is an urgent problem to solve. 'I cannot answer all the questions by myself and people want questions answered. The only way I can do it is develop this digital AI,' he says. Kruszelnicki's achievements as a science communicator are unparalleled: in Australia he's considered a National Living Treasure, he won the Unesco Kalinga prize, he wrote dozens of books and is the one and only Julius Sumner Miller Fellow at the University of Sydney, a position he has held since 1993. 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Sign up to receive it in your inbox every Saturday morning after newsletter promotion Kruszelnicki plans to run his digital self for 100 days because 'it's a nice round number'. He will also deliver 100 TikToks, one a day, alongside the project and each one will push people to his Digital Dr Karl, Stark says. After 100 days, the pair will switch off their AI and 'work out what the fuck just happened'. At that juncture they will do a survey with the hope that the result is that 'more people are open-minded and believe in climate change', says Stark. Kruszelnicki says they're just 'trying to do the Mark 1' and will see what they find before deciding whether they go on to a Mark 2. There are some hints about what could happen. Mounting evidence – academic and anecdotal – suggests LLMs can influence emotion, opinion and belief. 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Daily Mail
7 hours ago
- Daily Mail
The surprising similarities between near-death experiences and psychedelic drug trips – and why both mean seeing a bright light
Across hundreds of reported near–death experiences, people see the same things with staggering consistency. Now, scientists have discovered that these brushes with death share a surprising similarity with another type of mind–altering experience. According to new research, psychedelic drug trips and near–death experiences often result in the same bizarre visions. Strikingly, a bright light at the end of the tunnel is seen in 'nearly all' high–dosage experiences with certain drugs. Both types of experience also produce feelings of detaching from the body, encountering supernatural beings, and travelling mysterious spaces. Similarly, both potent drug trips and near–death experiences (NDEs) can be some of the most transformative moments in a person's life. Researchers now say that the striking similarities between these different experiences might hint at a common underlying mechanism. Dr Pascal Michael, of Greenwich University, told the Daily Mail: 'Both states share the same neurobiological 'scaffold,' but individual psychology builds different experiential 'stories' on that foundation.' What are the similarities between near–death experiences and psychedelic drug trips? In a recent trial, Dr Michael and his co–authors from Greenwich University compared people's subjective reports of drug–induced trips and NDEs. In the study, 36 participants took a high dose of vaporised DMT – an extremely potent psychedelic and the main active component of the Ayahuasca brew. Researchers then compared the details of the participants' trips to a database of near–death experiences triggered by heart attacks. What they found is that both types of experience share a surprisingly large set of common attributes. For example, people in both cases reported feeling 'disembodied' and travelling to a new location or through a strange space. 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Different cell types have different capacities for survival, including white blood cells in humans. However, researchers suggest that their similarities could be caused by the common physical structure of our brains. Dr Michael says: 'The common structural experiences – such as disembodiment, entities, environments, ego dissolution, timelessness, and visual intensity – stem from bottom–up neurological effects.' For example, the vision of a tunnel could be triggered because both experiences impact our brain's visual processing centres. During a DMT trip, the activation of serotonin receptors in the brain 'disintegrates' the networks that inhibit activity, leading to an explosion of spontaneous stimulation. During an NDE, meanwhile, the physical stress on the brain pushes the visual system into 'hyperexcitability', producing visions of bright lights and tunnels. In some cases, a powerful DMT trip could be so overwhelming that it actually produces an NDE. 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However, there still isn't evidence to show that DMT concentrations in the brain reach truly psychedelic levels during cardiac arrest or other extreme states. 'The neurobiology of both DMT and the NDE continues to be under–researched and the theory remains highly debatable,' says Dr Luke. How do NDEs differ from psychedelic drug trips? In addition to finding how these experiences were similar, Dr Luke and Dr Michael's research also found a number of important ways in which they differ. Although the types of visions experienced can be similar, they are often wildly different in content. For example, people undergoing an NDE sometimes report encountering dead loved ones or people they knew in their lives. People taking DMT, on the other hand, report encountering bizarre insectoid or octopus–like entities. 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In fact, the researchers say that explaining why these experiences are so different is the 'big question'. The researchers believe that these may be caused by 'top–down cognitive factors' such as cultural expectations, memory, personal belief systems, and context. But how exactly our personal psychology builds the unique character of a near–death experience, or overwhelming drug trip, remains mysterious. WHAT DOES DYING FEEL LIKE? Scientists reported in October 2017 that they had discovered a person's consciousness continues to work after the body has stopped showing signs of life. That means they may be aware of their own death and there is evidence to suggest someone who has died may even hear their own death being announced by medics. A team from New York University Langone School of Medicine investigated the topic through twin studies in Europe and the US of people who have suffered cardiac arrest and 'come back' to life, in the largest study of its kind. Study author Dr Sam Parnia told Live Science: 'They'll describe watching doctors and nurses working and they'll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them.' He said these recollections were then verified by medical and nursing staff who reported their patients, who were technically dead, could remember details of what they were saying. Doctors define death based on when the heart no longer beats, which then immediately cuts off blood supply to the brain. Once that happens, blood no longer circulates to the brain, which means brain function halts almost instantaneously. You lose all your brain stem reflexes, including your gag reflex and your pupil reflex. The brain's cerebral cortex, which is responsible for thinking and processing information from the five senses, also instantly flatlines. This means that within two to 20 seconds, no brainwaves will be detected on an electric monitor. This sparks a chain reaction of cellular processes that will result in the death of brain cells. However this can take hours after the heart has stopped, researchers said.
The Guardian
7 hours ago
- The Guardian
A huge stick insect has been discovered in Australia. Here's why that's important
Scientists recently announced they had found an enormous new stick insect in Australia. At 41cm in length and weighing 44g, the main question I heard was: 'Why didn't scientists notice something that big before now?' The short answer is: it's a stick. Stick insects spent over 100m years perfecting their cosplay as leaves, branches and moss. They are diabolically difficult to spot, even with fairly acute human vision. If you disturb a stick insect, its usual response is to fall to the ground and lay still. So now you are looking for a stick lying on the ground … among all the other sticks. Scientists were alerted to the presence of this new insect, Acrophylla alta, by a photo posted on iNaturalist, the community science sharing site. Based on that image, they spent several nights tramping through a rainforest with headlamps and flashlights, hoping for a glimpse of this rare new beast. They eventually located and knocked the stick insect off of its perch, which can be 30 metres up in the tree canopy, with a long (actual) stick. Phasmids (stick and leaf insects) are an incredible example of natural selection at work. As herbivores quietly munching leaves, stick insects are a delicious snack for many other animals. Evolution shaped the 3,500-plus described species of phasmids into stunning examples of camouflage, usually by pretending to be objects that are irrelevant to predators: sticks, bark and leaves. They solved the problem of hiding in plain sight through a variety of forms most beautiful and wonderful; their bodies range from long skinny tubes to wide and flattened leaf shapes. Stick insects are grouped into delightful categories with names like broad prickly sticks, winged bark huggers, stout crawlers, narrow leaf mimics and tree lobsters. The last is a group best described as insects that gave up on the whole delicate leaf and twig act to become heavily armoured, spiny tanks – determined to make a predator profoundly regret ever trying to eat them. As a former keeper of stick and leaf insects in a bug zoo, I can attest to just how good these animals are at being invisible. Even when you knew there were exactly 10 leaf insects in a cage, finding numbers 9 and 10 always involved a long manual search of every single branch and leaf, sometimes requiring multiple people. Jungle nymphs (Heteropteryx dilatata) are 17cm lime-green spiky monsters that somehow manage to disappear into foliage despite their size. Often you only discovered one by getting a painful kick from a spiny leg. The recently described Australian stick insect also lives in a rainforest tree canopy, so it's not surprising it remained hidden for so long. Insects and their relatives are the animals science knows the least about, despite being some of the most abundant organisms on Earth. After almost three centuries of taxonomic research, scientists have only described and named about 1m insect species; thousands of new species are added to that total yearly. The question is not why weird new insects keep getting described by science, but why there aren't more strange insects, spiders and other relatives with extra legs being discovered daily. Research suggests that at least 5m insect species exist, and insects and their relatives (arthropods) make up 85% of all known animal species. To put that in context, there are as many species of just ladybirds as there are of all mammals combined. The International Union for Conservation of Nature's (IUCN) Red List of Threatened Species is a good benchmark to get a sense of how little we know. IUCN is the primary information source on the global conservation status of animal species, but its database lists only 1.3% of known insect species for evaluation. For the entire category of insects, the most species-rich animals on our planet, IUCN's data table simply says 'insufficient coverage'. It simply doesn't have enough data to estimate the percentage of threatened insect species. Naming and describing is just the first step of understanding and preserving our biological diversity. For many species, we have no idea where they live, what they eat, or what their lives are like. Of the insects listed in the IUCN database, 26% are listed as 'data deficient'. This adorable little willowherb leafcutter bee is extinct in the UK, and we don't know enough about it to say much more than that. By focusing on large, charismatic animals, we miss understanding the little animals that run our world and provide essential ecosystem services. It's little invertebrates that pollinate plants, feed birds and other animals, and keep soils healthy. They deserve to be studied as much, or more, than their bigger vertebrate kin. Concentrating on common threats to animals, big and small, can help us make better choices about prioritising research and conservation. Gwen Pearson is adjunct faculty at Michigan State University Department of Entomology. She received the Entomological Foundation Medal of Honor for her work in education and science communication
