First climate tipping point triggered; Man controls another person's body by brain implant; health worries over sumo wrestlers

0:00We do have bad news this week. The first global tipping point for one of Earth's ecosystems has been triggered. There's been a jump in ocean temperatures and mass bleaching and death of corals globally, affecting more than 80 % of the world's corals. And the crucial thing about these tipping points is that they're irreversible. Once they're gone, they're gone. Scientists have been screaming, no one is listening. We've got an exclusive report on a man with paralysis who's been able to move and sense another person's hand as if it was his own, thanks to telepathic brain implants. Amazing. One day this sort of development could lead to...

0:36Avatar. And there's a sumo tournament in London this week, and we're going to hear about the physiological effects of being a sumo wrestler. 15 years ago, we were still at the stage where we were banging our heads into wooden poles to toughen up the skull. It's a ticking time bomb.

0:54This episode is sponsored by Yakult, the gut experts for over 90 years. Welcome to the world, the universe and us. I'm Dr. Penny Sarchet. And I'm Dr. Rowan Hooper. Now, there's still time to get your ticket for our festival of Science and Technology, New Scientist Live. It's being held in London on Saturday the 18th and Sunday the 19th of October. There's also a school's day on Monday the 20th and there's so much going on. Talks on archaeology, gravitational waves, the microbiome. Dark matter, human reproduction, climate change, loads. Plus we're recording a podcast live from the show. Yep and if you can't make it to London you can also watch it online.

1:30Search New Scientist Live to get your tickets and And if you're there, please come and say hi. Now, this week, I'm afraid we've got to sound the climate alarm because there is some huge news about the state of the world's oceans. Yes, we've been reporting for a couple of years now about this rapid acceleration in ocean heating that we've seen since 2023. And it now seems the rising water temperatures have pushed the world's warm water corals, which are already struggling right to their limits. And here to tell us more about it is new scientist environment reporter Madeleine Koff. Hi, Maddy. Hi, guys.

2:01Maddy what's happened to the coral? Yeah I'm afraid I bring some bad news so the major news this week is that scientists have officially declared that there's been a widespread dieback of warm water corals over the last two years that in effect means that the first major global climate tipping point has been triggered and we do talk about tipping points a lot and the odd thing about them is that these ones these climate tipping points as scary and monumental as they are it's not actually clear when exactly you've triggered them right you don't necessarily know if you're in the middle of it right now.

2:33Yeah, so a climate tipping point for people who aren't aware, these moments when there's a small change in a system that makes a big difference to the overall state or fate of that system. So in climate terms, it's where we push an ecosystem like the polar ice cap, for example, or a coral reef to the limit of its survivability. And then all of a sudden it will either die back or disappear and kind of change the way that ecosystem works completely. And the crucial thing about these tipping points is that they're irreversible. Once they're gone, they're gone. And the system has shifted into a new state that can have catastrophic knock-on consequences.

3:13And yeah, Penny, as you say, it's often really difficult to spot when a climate tipping point has been triggered. Unfortunately, or fortunately, in the case of warm water corals, they're probably one of the most straightforward ones to pinpoint because warm water corals are very sensitive to even marginal changes in water temperatures. So if temperatures climb by more than a few degrees above normal, that can bleach and then essentially kill off the corals. And if that dieback happens too often or is too widespread, then the corals can't recover and they die off in the ecosystem that they support and the marine life that they support vanishes.

3:48Yeah, and in case people don't grasp quite how important that ecosystem is, They support up to a third of all marine biodiversity, a third. And that's just in a tiny amount of the area of the ocean. And they provide food, coastal protection and, you know, income to millions of people living there. Protection all around the world. Yeah, the statistics around the benefits that warm water corals provide are pretty staggering and quite difficult to get your head around. but to break it down into kind of pure economic terms they're worth almost 10 trillion dollars to the global economy and like you say rowan that's not even mentioning the fact that they act as a nursery for marine species so they they essentially prop up other ocean ecosystems so this is a real classic tipping point where a small change the demise of one small bit of ecosystem can push a system the way the world's oceans work past a point of no return.

4:49So how have scientists gone about declaring right now that this tipping point has now been reached? Yeah good question it does get a little bit technical so bear with me. So central academic estimates suggest that the thermal limit of warm water corals is reached when global atmospheric temperatures hit 1.2 degrees above pre-industrial levels or above with an upper threshold of 1.5 degrees. So the long-term average temperature at the moment is about 1.3 degrees above pre-industrial levels. That's the amount of warming we've already caused. But in 2024, we obviously saw a huge surge in global temperature and that pushed average global temperatures up to that 1.5 degree limit for the first time in human history.

5:33That's all to say that we've definitely now passed that central 1.2 degrees temperature estimate for corals for their thermal tipping point. And last year we bumped up against the upper 1.5 degree limit. The other thing to note is that since 2023, as you mentioned, Penny, the world corals have suffered a huge bleaching event that's impacted more than 80 % of the coral ecosystem in the world. That's by far the most severe and extensive bleaching that we've seen on record ever. As Tim Lenton at the University of Exeter put it to me, we've taken a sample of the 1.5 degree world and we've seen the consequences.

6:09So if they're saying we've passed this central estimate, we're already seeing that we're basically going to go past 1.5 degrees. It means we're going to go past the upper estimate as well. Yes, so at this point, unfortunately, it's virtually certain that we're going to see the widespread die-off of warm water corals around the world. It's almost incomprehensible really the impacts and also just how sort of tragic that loss is. Hard to imagine ocean health or biodiversity without it. Is there anything we can do? Yeah we're really entering uncharted territory here and unfortunately at this point there isn't that much that can be done.

6:45I mean we can help to protect the existing corals as much as possible by reducing the other pressures that are on them like overfishing and water pollution for example but that doesn't get away from the fact that the main thing that we would need to save the corals is a global concerted effort to get global temperatures back down to at least only 1.2 degrees above pre-industrial levels and ideally lower than that and given that it's looking pretty inevitable that we will exceed 1.5 degrees of warming I certainly wouldn't put any money on 1.2 degrees being at all feasible in the near term and certainly not anywhere like the time frame that we would need to save the corals.

7:25Is there a feeling that our media in Europe, in the UK and in the US consider this a sort of global south problem and that there hasn't been the reporting on it that there should have been? Because, you know, we understand from our work as journalists, science journalists, the real importance of corals. But do you think it's sort of out of sight out of mind yeah is it just a tourist thing for us you know those of us who don't live near these amazing reefs yeah i was thinking about this i mean it was this news has been covered by some major news outlets but there's certainly no sense that it's been kind of front page talking point in the uk and north america and i do think that if we were talking about one of the other tipping points that was closer to home so for example a collapse in ocean circulation in the North Atlantic, then that really would kind of dominate the airwaves.

8:21And I do think that there is a kind of out of sight, out of mind problem here that extends to not just the fate of the world's corals, but also to other issues around climate change. Like I've just been pulling together a big piece on the future of solar power. And everybody I speak to who says that solar energy is going to change the game and the way that we run the world in the long term. But it just doesn't seem to be a narrative that has caught hold in parts of the Northern Hemisphere because we have long dark winters and therefore solar is probably not going to be our dominant energy force in that part of the world.

9:00But for the rest of the world, it will power everything. So I do think there's a kind of blinkered view that we have that if something doesn't directly affect small parts of the northern hemisphere that are the richest in the world then we don't really consider it in the same way but these these issues have massive global importance and will change the way everybody has to live and exist in this world so having now hit this first climate tipping point uh you mentioned some others there are there are there other ones looming like coming along the track unfortunately yeah there are a few that scientists think are probably the most likely to come next as we've said it's really difficult to pinpoint exactly what level of warming might trigger a tipping point and and the triggering of one tipping point might hasten the arrival of another one so we could be really uncertain about the timings here but the next ones that are coming down the track is likely the widespread dieback of the amazon rainforest the melting of the polarized sheets and the collapse of this crucial ocean current in the North Atlantic that's known as the AMOC.

10:05And those could all happen at warming levels of below two degrees Celsius above pre-industrial levels. Another story that you reported on, Maddy, this week was the jump in carbon dioxide concentrations. It's now reached a record of 423.9 parts per million. And I saw there's a conference going on in London at the moment, the Blue Earth Summit. I saw Mike Berners-Lee there, the climate writer, and he was saying there's mounting evidence for these cascading tipping points that you're talking about. And he said the language in scientific papers is as close to screaming as you'll get in an academic journal.

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11:23Next up, we've got a slightly spooky story, just as Halloween draws near we've got a man with paralysis who is able to move and feel sensations through another person's hand amazing so Carissa Wong you're here to talk to us about it how does this work? Yeah it's a slightly strange but absolutely fascinating story and researchers have as they put it essentially made a mind-body connection between two different individuals and it all began in 2021 when researchers started working with a man in his 40s Keith Thomas, he had paralysis after a diving accident that left him paralyzed from the chest down and that left his arms and hands essentially unable to move or feel any sensation.

12:08So Keith was telling me he was looking for a way to regain some of these abilities so he agreed to have five sets of electrodes implanted into the part of his brain that controls the movement and sensation in his right hand and essentially these electrodes transmit his brain activity to a computer that then decodes that activity into signals that are sent wirelessly to electrodes that are worn on Keith's arm and those electrodes on the arm then stimulate his muscles with electrical signals allowing him to contract and relax those muscles and open and close his hand. That's really interesting but I lose track of it because there have been a lot of studies over the years looking at things like brain implants and BCIs for paralysis.

12:53What's new about this one? Yes, you're right. So what made this so cool was that Keith also wore four sensors on his fingers and these four sensors transmitted the sensation of objects pressing against his hand into his brain implant which then stimulated his brain activity so that he had a sense of touch. So instead of just going from the brain to the arm muscles it went the other way as well. Exactly. And this allowed Keith back then to feel objects and move his hand for the first time in years. And he was telling me, you know, some of the most emotional sensations he got to feel again were like the fur of his pet dog and holding his sister's hand again for the first time in years.

13:36Wow. It sounds really emotional and amazing. But how does this then get to this telepathic thing of feeling what someone else is feeling? Yeah, so in this latest study, Keith has now used this same setup to control and feel sensations through other people's hands, which, yeah, it's pretty wild. So essentially, the researchers got someone who wasn't paralyzed. They got her to wear the arm electrodes and the four sensors on her thumb and index finger. And essentially, Keith just had to think about opening and closing his own hand and it opened and closed her hand. Wow. So then it must have felt to him like that was his hand.

14:20Yes. He gained ownership of it and she'd given it up. Yeah, what must it have felt like for her to feel that? Yeah, yeah. What did it feel like? Yeah, so she was told not to intend to move her hand at all. So she did have to completely relax and give him the control of her hand. What if she punched herself in the face? That's not very nice. She's let you. Yeah, I know. Yeah, and I do know what it felt like for Keith. I spoke to him and he said it did feel quite strange to start with, but then he said you sort of get used to it. And because she was wearing those four senses on her fingers, like he could feel her picking up objects.

14:59So that was like as if it was his own hand. But you might think, I like this, actually. You're not having it back to the woman. I want this hand now. She might have something to say about it. She might do, but you can imagine in the future, a scenario where there might be some sort of you might pay someone yeah to say okay you just give me the control of your body for the next year i'll give you a million or 10 million dollars any sci-fi authors out there listening yeah there's one yeah yeah we can get on to that a bit later yeah i jumped the gun yeah so i was just going to say that in a test that keith did he was blindfolded and the other person picked up three types of balls one was a soft foam ball one was a denser form of that ball and another ball was was a baseball and Keith was able to distinguish between these three balls with 64 accuracy based on the hardness of those objects but he wasn't able to feel things like the texture of the surface of the balls or the curvature well early days but you know that's not too bad that amount of accuracy is it yeah it's not terrible It could be improved and luckily it can be improved.

16:12So Chad Bouton, the researcher involved in this study at the Feinstein Institute for Medical Research in New York, said this figure could be easily improved if you essentially optimise the number of force sensors that are on the second person's hand or to those angles. and he also said it should be possible to feel the shapes of various types of objects if you put a few more electrodes in the brain and also adjust those four senses. And what's the stated aim in all this, without getting into the sci-fi quite yet? Like, what is there? What do they want to do? Why did they do it? Yeah, it's a very good question.

16:48This isn't just a wild experiment. So, you know, also in the study, they got Keith to control the hand of another paralysed person, So a woman who had very little movement in her fingers. And so she struggled to do things like pick up a drink and take a sip. So what they found is by getting her to wear the arm electrodes and the force sensors, Keith could use his thoughts to assist her in being able to carry out those kind of tasks. So like drinking from a can in this case. So the point of this is that you could have this kind of collaborative rehabilitation for people with spinal cord injury.

17:28Keith, with just his thoughts, was able to help her to gain some abilities. And it wasn't just while he was thinking about it. The researchers told me they found after a few months of working together, Kathy, who was the paralyzed woman, had actually had nearly double the muscle strength in her arm, the grip strength, compared to before she was working with Keith. So there are real improvements. So is that a better way of doing it than the kind of traditional way of sort of using electrical stimulation that we might have done before this? So no, standard therapies that involve stimulating our muscles or like neurons can lead to similar improvements in like grip strength and things like that.

18:12But the real kind of selling point to this approach is that, as the researcher said to me, it's a much more socially enriching and engaging way for people with paralysis to work with each other. So, you know, in standard rehabilitation, people will work with physiotherapists and things like that. But there is a real value in them working with other people who have experienced something similar. So Keith told me it actually was pretty amazing. You're helping someone by just thinking about it. And he also said there's benefit from just talking to them like the other person. How's your weekend? And that makes you feel good about yourself.

18:48And it makes them feel good about themselves, too. I also spoke to Rob Tyler who is paralyzed and a lay member of the scientific committee at this spinal cord charity called the Inspire Foundation. And he echoed sort of what Keith's experience was. He said that he really did think for some people with a spinal cord injury, this could help them to be motivated to rehabilitate themselves. Which, you know, can get a bit boring and it's easy to kind of feel like you're not seeing much improvement. but having someone else there who's working with you can really help you to have that motivation to keep working on yourself and he also said you know after you experience a spinal cord injury you've got to kind of find a new identity there's things you can't do and and having someone to talk to about that who's really involved in your recovery can really help yeah it does sound really motivating and and rewarding to do something together like that and I suppose that helps overcome the the ick factor basically of letting someone invade you invade your body and letting them use use your neural system for a while yeah you're right to say you know it is a pretty invasive you know to have someone sort of inhabiting your hand and and hands aren't just hands they're the really personal things that allow us to do so many different personal tasks in our lives so it is going to be really important as Rob told me that you appropriately match people with paralysis so that they do share motivations and outlooks and of course they must feel psychologically safe and comfortable with each other if you're going to pair them to do this because psychologically if you've lost the use of your hand just on an emotional level however much you trust the other person to have someone else basically being able to control it it's quite a difficult thing to swallow but I can see how with physio it can be so gruelling, so demanding, anything that sort of boosts that social connection and builds the motivation, you can see the power of it, won't you?

20:46Yeah, it's really deep stuff, isn't it? It's really wonderful. About the sci-fi side of it, did you ask him about that, those sort of more far out aspects of it? Yeah, of course, it's such an intriguing idea. So I did ask Bhutan, the researcher, and he really did envision that one day this sort of development could lead to... Avatar. Yes, people remotely interacting with each other in a way that's never been done before. You know, people sharing sensory experiences, collaborating on tasks through these mind-body connections happening thousands of miles away. He said, yeah, this could be a whole new way for humans to connect on a new level.

21:30but of course that does come with ethical issues this is by no means going to be you know something that happens in the next five years and as harith akram at university college london hospitals told me it brings up that question is it good or bad for society for people to be able to control and feel through other people and he said you can imagine you could cause harm to another person through their own body or commit a crime by controlling their body and then say it wasn't me Yeah, I get that. But let's end on, I think this is a really positive, lovely story. And let's end on all the good that this could do.

22:04And we'll keep that other stuff in check. Yeah, sure. Rowan, you've been at the sumo. I have. I love the sumo. There's a grand sumo tournament here in London. It's only the second time in history, in all the ancient history of sumo, that they've held one outside of Japan. The last time was in 1991. And was that also here in London? At the Albert Hall, yeah. So they've brought in tons of soil and clay and they've built a proper dojo, the circle that the wrestlers fight on. And they've built like a shrine roof over it. And they basically transformed it into this little island of Japan. It's really great.

22:46And seeing the sumo wrestlers around London and there last night, there's just something wondrous for me about seeing them. They're just huge, strong and, you know, otherworldly. I'm jealous. Every time I pop out for lunch and come back, someone tells me I've just missed them. You should have longer lunch breaks. Yeah, this is true. All really interesting. But what's the science connection? How are you going to concoct one here? So I have managed to concoct one. So there's no weight division in sumo like there is in boxing, right? So you can have a relatively small guy matched up. say he's only 120 kilos, fighting a guy 60 kilos on top of that 180 kilo.

23:29And so you really have this David and Goliath type matchups. And that means there is some interesting physics. I mean, there is some interesting physical, like what strategy do you use to lever someone out? That's the sort of physics side of it. Then there's a diet of sumo wrestlers as well, of course. right yeah so they must eat so much to so much yeah and they make this famous dish called chanko nabe which is really delicious um i only eat it in small bowls they eat vast amounts of it but there's also some quite worrying stuff about their longevity actually yeah it can't be good to eat that much and maintain that large size for so long yeah exactly so to find out more about this i spoke with John Gunning.

24:13He's a sumo writer for the Japan Times in Tokyo, my old place, and he commentates for the sumo for Japanese TV and he runs Inside Sport Japan. This is a media sport company and he was an amateur sumo wrestler himself and here he is. John, thanks for joining us. Welcome to the pod. I want to start with a bit of physics and then get into the physiology of sumo. And so for people who might not know much about it sumo is this game for two people one has to push the other out of a ring or make them fall over and naturally that means that the bigger you are the better right so that's the physics to a certain extent but because it's down or out as you said and there's balance involved it's not just merely size because there's also the element at the beginning of a fight where you could do that kind of all a dodge to the side so if your momentum will carry you straight out of the ring if you're too big and you can't stop all that mass moving forward.

25:11So there is a certain sweet spot in height and weight in terms of ratio. But even in the top division, there's a wide variety of body types, heights, weights, sizes, and skill sets. But generally, you do have to bulk up to get to that sweet spot. Yeah, there's a certain minimum and maybe, yeah, maximum as well, we'll say in terms of height and weight, that's where most people will be within those ranges. Yeah, okay. Take us through a typical day, a sumo stable, maybe a bit about the diet. And let's get rid of this myth that they eat 10 ,000 calories a day. Yeah, I don't know where the original 10 ,000 calories came from.

25:57I think it was a journalist before my time, but it stuck like a few other things. Because it's such a set number, it's like saying a football player eats a certain amount of calories. It's so varied. Each person is different. It depends on your height and your weight and how hungry you are on that day, what you're eating, what you're eating out. They do eat a lot more than, say, the regular person. They do eat more regularly, even though people don't seem to realize that. They think they just eat once or twice a day. But, I mean, sumo wrestlers are snacking constantly, a lot of them throughout the day.

26:26they're young, they're men in their late teens to early twenties, mid twenties that most of them. So, you know, they, their energy requirements are high anyway. And they're put, they're then in this incredibly intense sporting environment that, you know, requires like full active participation for hours every morning. So they, they do put in a lot of calories. Um, but again, it depends on the person, the size and the particular day. They would eat a lot of rice, you know, large bowls of rice. But the basic meal after training is what's known as chanko nabe. Chanko is just a sumo word that means food, and nabe is a kind of soup stew that maybe a lot of people would know about.

27:07But I mean, in terms of vitamins, minerals, macronutrients, stuff like that, it's very healthy. You know, there's a lot of vegetables, there's a lot of lean meat, chicken, fish, stuff like that. So it's just the amount, really. You know, they're eating healthy food, they're just eating a lot of vast amounts of it vast amounts when i was in japan um there was a famous foreign-born wrestler called akibono and he was definitely on the outlier of what you've just said he was he's six foot eight so over two meters tall uh weighed 233 kilos and very sadly he died last year aged only 54 and there have been studies showing that the wrestlers have a much lower life expectancy than the average, certainly the average in Japan, and maybe 15 years less than the average.

27:57So there is this bad, very bad physiological effect that it has, not just on the heart, but the other injuries they pick up, right? Yeah, Akibono, obviously, somebody I knew very well. It was very sad when Chad Rowan was his name. You know, his last name is the same as your first name. But he, you know, him, Musashimaru, Konishiki, the Samoan Hawaiians, obviously genetically, we're talking about a very different body type there. You know, they're, they're, they're very large individuals anyway, but you can't disagree with what you said there. The fact that sumo takes a massive toll on your body.

28:33It's, and it's not just the weight related stuff. It's, you know, your body, like even when I was doing sumo, you know, 15 years ago, we were still at the stage where we're like, you know, banging our heads into wooden poles to toughen up the skull. Like that was the mentality, you know, the CTE and, you know, microtraumas to the brain and the repeated impacts and the concussion, all of that, I mean, still really hasn't seeped into sumo's consciousness. So that's obviously taking a toll on people. I mean, I feel it myself. I was an amateur, but I trained with pros for 10 years. And, you know, I have, you know, discs out of place, my back, neck, like lingering injuries.