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Green Fix
Positive Tipping Points with Prof. Tim Lenton, Director of the Global Systems Institute, University of Exeter
Welcome to Episode 1 of the Positive Tipping Points Special! A 7-episode special series on the road to COP30 in Belem, with guest host Liz Courtney.
What if the smartest way to cut climate risk is to make progress contagious? We sit down with Professor Tim Lenton to decode climate and positive tipping points—how small, smart pushes can trigger self-propelling change in technology, policy, and social norms.
Tim unpacks why systems slow down before they snap, and how that same nonlinear logic powers breakthroughs: Norway’s EV market tipping to ~95% battery electric sales through activist-driven policy, learning curves that crushed battery costs and boosted range, and solar’s decades-long price freefall that’s delivering the cheapest electricity in history. We dig into green hydrogen for zero‑emissions steel, green ammonia shipping that cleans port air, and synthetic aviation fuels that cut contrail warming—plus the policy mandates that can push these solutions over the edge so scale takes care of the rest.
Your Hosts:
Dan Leverington
Loreto Gutierrez
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Welcome to the Green Fix, a positive tipping points special series with guest host Liz Courtney, an award-winning film director and science communicator. This seven-episode weekly special is offering a fresh lance on the climate conversation. It will explore the science of solutions and the many sparks of change already underway in the moments when small ships create a big impact. Expect good news stories, evidence of real progress, insights on the urgency of acceleration, and above all, a huge dose of optimism about the world we can build together. Enjoy the show.
Dan Leverington:Welcome to the Green Fix Positive Tipping Points. I'm Dan Leverington.
Liz Courtney:I'm Liz Courtney.
Loreto Gutierrez:And I'm Loreto Gutierrez. And for the opening episode of Green Fix Positive Tipping Points series, we are unpacking positive tipping points with Tim Lenton, professor of climate change and earth system science at the University of Exeter, but he also serves as the director of the Global Systems Institute. He's internationally renowned for his pioneering research on climate tipping points, earth system modeling, and the Gaia hypothesis, which explores how living organisms interact with the planet. Tim Lenton has received numerous awards for his climate science research, including an officer of the order of the British Empire in 2025. His latest book, Positive Tipping Points, How to Fix the Climate Crisis, has just been released and he has been a significant inspiration for this limited series. Thank you for joining us, Tim. Great to have you on the podcast.
Tim Lenton:Great to be on the show.
Liz Courtney:We wanted to just wind back before we talk about the book and the positive tipping points, just to really wind back and understand what climate tipping points are. Could you dive into just taking the listen through uh what those tipping points are and how you started to discover that the climate and explain it as a system, which was really a new vernacular back in 2012, 2013?
Tim Lenton:Sure thing, Liz. Maybe I should just try and land the concept of a tipping point for everyone. So if you're on an ordinary kind of chair, you can always lean back to that balance point where you can remind yourself that a small nudge one way or the other can make a big difference to the state or fate of you than the chair, the system in this case. You could end up sprawled on your back on the floor if you nudge one way, or back upright if you nudge the other. A small change is making a big difference to the system, and once that change starts, it gathers its own momentum, if you like. It gets stronger and stronger, it's self-amplifying, and you might wheel your arms around frantically trying to rescue the situation, but it's pretty difficult because that's the nature of tipping point change. It tends to be self-propelling, and that makes it hard to reverse. So I was interested from more than 20 years ago in trying to spot the bits of the climate, our life support system, where our activities, global warming in particular, could tip bits of the climate system into a state that would be worse for us. And in short, we could see even then that there was a possibility to tip the irreversible loss of major ice sheets that would commit us to large amounts of sea level rise, which would be a problem. We could commit the loss of big parts of the biosphere, like the Amazon rainforest, into a more degraded kind of savannah state that would be bad for the regional climate and add lots of carbon to the atmosphere, making it worse for everybody. And also we could tip changes in ocean circulation and atmospheric circulation like the monsoons that would change the whole pattern of climate and make it a big challenge to adapt to. So yeah, I saw my task initially was let's map this stuff out and let's try to sense how close we are to some of these tipping points. Also, what can we do to avoid them? Because some of them, the consequences are so big and bad, we should be doing everything in our power to avoid or minimize the likelihood of crossing them.
Liz Courtney:And with those tipping points, would you be able to just name some of those elements in the system that you've been observing?
Tim Lenton:Well, the tipping elements in the climate that we're most concerned about in the sense that they might be the closest to their tipping points, they include one that we've probably almost certainly crossed, which is widespread dieback of coral reefs in the tropics, including the Great Barrier Reef. Everybody should be aware that uh those those reefs have just experienced the most extreme marine heat wave and bleaching and destruction ever, on top of recent other devastating marine heat waves. And about 500 million people variously depend on coral reefs in the tropics for their livelihoods. So that's quite a big deal. We have two big ice sheets, Greenland and West Antarctica, where we already see accelerating loss of ice from those ice sheets, and we're struggling to rule out whether they've crossed a tipping point or not, at least in parts of the ice sheets. If you lost the whole of both of them on the long run, you get ten meters of sea level rise, and at least a billion people live within ten meters of sea level. In fact, about 250 million live within the first meter of sea level rise. And then we have permafrost, which is our fancy name for frozen soil in the high Arctic. There's an enormous amount of carbon in the deep freeze at the moment, but it's thawing in a way that's abrupt. We're seeing in some locations the sudden thaw of the permafrost, the creation of lakes, the outgassing of carbon dioxide and methane that adds to global warming. And beyond that, we've got a concern about part of the circulation of the North Atlantic Ocean. There are basically two places either side of Greenland where we call it deep water formation happens. The water gets dense enough to sink from the top of the ocean to the bottom, and that propels something called the Great Atlantic Meridian or overturning circulation. We're definitely seeing the formation of those deep waters at risk in what are called the Labrador and Ermiga seas to the southwest of Greenland. And if even just the collapse of that deep water formation would have, within a decade, pretty um striking consequences for the climate.
Loreto Gutierrez:Tim, that's really interesting. And you're monitoring and you have all this information. How hard is it to communicate this to the public and not just the scientific community?
Tim Lenton:Great question, Loreto. On the monitoring, what we have is a mixture of things. We have the trying to directly observe the systems, and then we also have what do we know happened to them in the past to show us what kind of behavior is possible. And then our models, our fancy climate models, um of of what happens when we play out in the model, say increasing global warming and greenhouse gas emissions from humans. Now the models are never perfect, but they give us actually some striking clues because a bunch of abrupt shifts and tipping points happen in the models. But we want to back that up with what we can learn from directly observing and sensing the systems. So we might expect, just like tipping over on the chair, that we'd expect to see change in a bad direction accelerating if we're near or passing a tipping point. And that's exactly what we see tragically for the declining height of the Greenland ice sheet and the loss of mass there, for example. But there's also a really interesting clue before you reach a tipping point. Before you reach a tipping point, a system, whether it's an ice sheet, the ocean circulation, or a bit of society, will get less good at recovering from little shocks it's getting all the time. Which in the climate is the weather. Because recovery is some kind of resilience in the system or damping feedback, we call it, that's being lost. And at the tipping point, some other kind of amplifying feedback is going to take over, and you're never going to recover from a shock. You're just going to go off into some other state. Now we've been busy looking hard in the data we have for big systems like the Atlantic Ocean overturning circulation, the Amazon rainforests canopy, the western part of the Greenland Ice Sheet. Um these are all systems that are showing this telltale sign of slowing in their recovery from little shocks and actually showing a bigger response to a little shock than they did before, which tells you they're losing resilience. So that's the observational challenge which we continue to master and develop. On the other side, how do I communicate to a broad audience? Well, I suppose I I try to convey what I've just done, which is this kind of core notion of what a tipping point is, and also this some of these ways in which we really can sense the behaviour of a system before it tips. And it kind of works for the example when you leant back on the chair near the balance point, because when you're near the balance point, movement initially is sluggish and slow. It's just it accelerates when uh you tip in either direction. It's a bit more subtle than that in these complex systems I'm talking about. So I'll often use movies of of tipping toy systems and things like this, and m movies of the actual data, for example, we have from sensing the Amazon rainforest, just to try and get the bits of our brains that actually are quite good at grasping complex systems dynamics activated, even if our conscious minds have been taught to tell us that complexity just means complicated and baffling, and I'm going to get paralyzed by the complexity. So, really, the art form is for the audience, everybody listening, not to just switch off when you hear complex system, not to feel disempowered and think, oh my God, enormous, complicated horror show, can't possibly understand it, but to realise there are some really ultimately quite simple governing principles here. But we have to grasp that change is not always what we call linear, which means outputs from the system, from the the inputs from our actions are not always proportional. We're not dealing with a clockwork machine, we're dealing with something that feels a bit more organic. We all experience going into a pandemic, and we all got a keen sense of how change can sometimes escalate way beyond their expectations.
Liz Courtney:It's really interesting to understand those time lags between what's happening in the system now that might have been something we did 15 or 20 years ago, and to understand what we're doing now in the next five years is going to really make or break what those sort of changes will be. Maybe you could unpack that a little bit.
Tim Lenton:Absolutely, Liz. So, first of all, uh in the book I just published on positive tipping points, I was trying to find a good metaphor to describe the fact that that indeed in the climate, certainly, there's always a lag between our interventions and the response of the system. And I I couldn't resist the Titanic as a kind of metaphor for this. It's a big ship, it's quite hard to turn, even when you see the iceberg straight in front of you. It's the same thing for supertankers. I'm afraid it's true in the climate. The climate is still trying to catch up or respond to what we've done historically, which is create an imbalance between the amount of energy coming in to heat the system up and the amount going back out to space. There's an excess of energy coming in, we call it an energy imbalance, that's pretty simple. The only way the climate can refine balance is to heat up, and as it heats up, that means it radiates more to space. But there's a lag in there because there's a thing we call a massive heat capacity of the ocean. It takes a lot of energy has to come in to heat the system up. So that's the climate. Even when we switch to human systems, we may also observe that people are trying to create change in the world. We can spend a lot of time being frustrated because we think, I tried so hard and nothing's happening, nothing's happening, nothing's happening. But remember that was always the case. It used to be when I was a kid, you'd go in a restaurant and people be smoking. That would be just totally normal. And you might think, Oh, this is disgusting, I wish they wouldn't do that, and you might be part of a public health campaign to try and get rid of it. But it for ages nothing happens, then bang, everything changes. And afterwards you're like, How could it have ever been like that? Because we've shifted what we call our social norms and shift uh our perception of the world. We should not despair when it comes to social change that we push, push, push, and maybe we don't feel anything's happening. This is the nature of tipping point change. We must remember this uh this this clue. Don't give up just because you're not seeing the response yet. That's why I've been working really hard, Liz, to develop this sensing capability so you can see the subtle clues before the tipping point. And that means looking for this slowing down of the system in response to little shocks. I'm now leading um big project, part of a big wider program, where we really want to raise the bar of the state of the art of those methods and apply them to particular bits of the climate. We are particularly concerned about what's going on with melt of the Greenland ice sheet, the fresh water pouring off Greenland, and then a potential tipping point in what I talked about earlier, which was this collapse of deep water formation in in the seas to the southwest of Greenland. Um and we're using that as a test case for what would be more general methods of spotting the telltale signs before a tipping point. Ha, these systems are slowing in their recovery from little shocks. But on top of that, the climate is indeed a complex thing. It's like a really complicated dance or orchestra. What's interesting is before a tipping point, if we take the orchestra metaphor, you might have particular rhythmic patterns like in an orchestral, and they're overlaid on each other to make the overall symphony, but the balance of those rhythmic patterns is going to shift often in a telltale way before the system tips. It's like the clue to a whole new actor is about to take over. That could be a pattern in both space and time of change that we're effectively developing the capacity with the other projects to look for and put new sensing instruments out in that part of the ocean, for example, if we can find this rebu reliable pattern to improve our skill in early warning.
Liz Courtney:The listener might be also saying, What if that um melt off Greenland or Antarctica does affect the ocean circulation systems, or if they slow down andor stop? What might that impact look like?
Tim Lenton:First of all, if we lose this formation of deep water which has got cold and salty and sunk from the top of the ocean to the bottom, normally it would mix up a load of cold water from underneath. So there's a s there's a fundamental shift in sea surface temperatures which then impacts the atmosphere, and that then shapes winds and the what's called the jet stream that's coming across the Atlantic. The last time this thing tipped, just in the seas to the southwest of Greenland, well we found an association between that and the change from what's called the medieval warm period to the little ice age in Europe. Art connoisseurs will remember the Dutch masters' paintings of frozen landscapes of Europe in the early modern period, and the fact that the Thames used to float freeze over regularly. In simple terms, we'd be tipping back to that more seasonal climate. Um that's a little version of what happens if we lose deep water formation in both regions, either side of Greenland, and we collapse what's called the Atlantic overturning circulation. That is like a big brother version of that, and you're removing a massive transport of heat across the equator and up to the North Atlantic region. So you suddenly put a massively more seasonal climate on Europe. The summers are still hot with unprecedented heat waves, but the winters could be every decade or extreme would be like minus 20 degrees C in London and minus 30 degrees C in Edinburgh, five and a half frozen months in Edinburgh, three frozen months in London. Infrastructure would fall apart. But in a global context, what you're doing shifting the position of a donut or ring of rainfall that goes all around the tropics, you shift it southwards if you stop heat transporting a massive amount of heat across the equator. That means you seriously disrupt or stop the monsoon in West Africa and in India, for example, as well as disrupting the North and South American monsoons. That could be a humanitarian catastrophe. If you suddenly have the rains failing in the Sahel, that's already a region of great conflict between settled farmers and pastoralists, unfortunately. So that won't help that situation. And in India, you're talking about over a billion people depending on the monsoon. So everywhere would be feeling the impacts, including the southern hemisphere, where the heat's got left behind. So it just adds to the warming there, and that can mean um bigger threat to the ice sheets of Antarctica. Extremes in either direction tend to be challenging for us in adaptation, in simple terms.
Dan Leverington:Now that we have this knowledge, thankfully, then means that we're we're not flying blind. How can it help us better understand the urgency of accelerating the energy transition and then also help us put in better mitigation plans in place across the globe?
Tim Lenton:Well, basically what I've told you should be reason to think do not want to cross some of these big bad tipping points. And actually we know that several of them lurk in the sort of range of one and a half to two degrees C global warming. There's always an uncertainty range on this, but we know that every 0.1 degrees C of warming is increasing the risk. And we know we're already at about 1.4 degrees C of global warming, and we will be tragically stampeding at this rate through 1.5, if not in 2030 soon after. So we should be saying to ourselves, Blimey, how can we stop the warming to control these otherwise probably unmanageable risks? And the only the only way to stop the warming is to stop the emissions of the greenhouse gases that cause it. So, in simple terms, we have to stop all fossil fuel burning and we have to stop the patterns of land use change which trace back to dietary choices and eating too much meat that also cause emissions. So we then should be asking ourselves, how are we getting on with what we call decarbonizing the economy to ultimately stop the emissions or get to what we call net zero emissions? Because we accept that some activities are really difficult to stop altogether, but we've got to counterbalance that with some net regeneration of nature, some regrowing of ecosystems that are going to suck up carbon and balance whatever residual emissions there are. Well, when we ask ourselves the question, how fast are we going to clean up our act? Unfortunately, the answer comes back way too slowly. A friend of mine, Simon Sharp, wrote a book called Five Times Faster a few years ago, because he calculated we need to go five times faster to have hold the warming below two degrees C with reasonable odds. Unfortunately, we haven't been going five times faster in the intervening few years, so I calculate we might need to go nearer ten times faster to have a reasonable chance of say limiting warming to about 1.7 degrees C before ultimately we hope to bring it back down again. That should tell us, wow, we've really got to step on the metaphorical accelerator pedal of transition. My case is basically the only plausible way we could achieve that kind of acceleration to clean technologies and behaviour change is if I can convince you there are also positive tipping points where the changes in technologies and behaviors and norms we need can also become self-accelerating, self-propelling.
Liz Courtney:Well, I think that is the perfect moment because you've given us the outline of what's at stake if we don't change. And I really love your new book that's just come out, Positive Tipping Points, where you really flip the script and say we need to understand that there are positive things happening in the world. We just need to put our foot on the accelerator and get that speed going. I'm really interested to know that kind of what really inspired you to actually write the book. There's some really lovely personal reflections at the start of the book.
Tim Lenton:Thanks, Liz. That's I feel very blessed as a person and and lucky as a kid. My grandparents love the mountains. They'd been founders of the Youth Hostel Association in the UK, and I would just jagged up the mountains as a kid. And I just I fell in love with nature right from the start. And then I fell in love with science as a geeky teenager and was passionate about wanting to study the earth as a as a living system, what what Jim Lovelock called the Gaia hypothesis. So as a scientist, you're full of wonder and at the majesty of it all and trying to understand how it works, which is which is great, which is why it's pretty traumatic when you also discover as a scientist what a what a what a what trashing we're doing of our life support system. And you're thinking, my God, I've seen this, I've seen the lice sheet melting away at an accelerating rate, and these massive bits of the ice sheet breaking off. And you're thinking, we've really got to change. Is there I convince myself that we could credibly get ourselves out of trouble? Because otherwise we're just left in a state of kind of despair or doomism, as some people are calling it. And that's why I doubled down also on working on the evidence that there's really good change happening in the world, clean technology and behaviour changes that have become, in some instances, incredibly fast and self-propelling. And I found that the only way I could generate plausible grounds for hope or conditional optimism that that there is a way to limit the unmanageable damages that are otherwise coming, and that we should all feel that agents seem to be part of creating the self-propelling change we need, that each of us acting creates amplification that brings more people on board and more and more and more. So that was the inspiration for the book. It's partly personal sanity, as well as I find so many people and so many audiences are just befuddled by the complexity of the climate's changing, and there's all this stuff going on in the world, and how could I how could little me even understand it, let alone make a difference? So I want to cut through that and show we have to brace the complexity up to a point to re because through that we realise the agency we have to be part of change.
Loreto Gutierrez:Such a good point, Tim, and particularly about the sanity and the much-needed positivity we need in in the field. Um I'd love to ask you what are some of the critical positive tipping points that you describe in your book?
Tim Lenton:It's all about the big activities or sectors of the economy that at the moment are causing a lot of emissions that could go to zero emissions. I talk a lot about how we transform our power supply, electricity, from burning fossil fuels to to embracing the solar plus wind revolution that's starting to unfold around us. And I also spend a lot of time on mobility, in particular road transport, because just cars and trucks is about 15% of emissions. The power supply I mentioned is about 25%. There's a really great story about the one nation that's led the world in tipping away from petrol and diesel cars to electric vehicles, which is Norway. Why Norway? This little cold country where the batteries shouldn't work as well in the freezing cold. Well, that one traces back to social activists, to members of the pop band AHA, who people like me are old enough to remember. Uh so Morton Harkett and his and his friend, professor of architecture Harold Rosvik, who no one would have heard of. These guys are buddies, uh, along with other members of the band and an environmentalist Frederick Haug. And in the late 80s, they're annoyed with their prime minister, who's called Grohan Bruntland, for preaching sustainable development to the rest of the world whilst increasing oil and gas extraction and exports in Norway, what you some of us would describe as hypocrisy. And they they start a campaign to say let's incentivize the transition to electric vehicles, because over in Norway they already have almost 100% hydroelectricity, it's cheap, they have good grid connections. Electric vehicles aren't as good as they are now, but they still existed back then. What they did is they came up with line policy demands that would incentivize the uptake of EVs, like waiving the import registration tax, waiving the VAT, waiving road tolls, and and they m started a campaign leveraging the fact that they're a world-famous pot band to draw it, draw this possibility to the attention of the people. And then they uh they actually imported a hobby converted electric vehicle to Norway. They got the import registration tax waive for that and every electric vehicle since. And then they fought almost a decade-long campaign to get their other demands met, which was great fun because they would drive the electric vehicle around the road tolls of Oslo and refuse to pay the tolls, get the vehicle impounded, it would go up for auction. Some one of their friends in the audience would buy it back and then give it back to them and they'd repeat the cycle. Anyway, after some years, they got a bunch of their demands in place, and Norway's experimenting with early EVs and the fact that they have like free access to bus lanes when you're when it's rush hour and you're trying to get your kids to school or you're trying to get to work, people see, oh, this is a good thing, I want one of those. Anyway, by the time major manufacturers put EVs on the market around 2010, 11, 12, the Norwegian population's already primed, and the cost of owning an EV is comparable for them as a petrol diesel car, and boom, they the market tips. It's now it's about 95% full battery electric vehicle sales in the Norwegian market. But the point is, in the bigger picture, if um there's some other really good amplifiers, it's not it's not just the amplifiers of what we call social contagion, it's the fact that the more electric vehicles, especially the more batteries we make, the better they get and the cheaper they get. Uh they've got about a factor of ten cheaper in a decade, which is amazing. And the range you can get from a given battery has gone up by a factor of three almost in a decade. This is spectacular. This is making each person who adopts now improves the technology in a sense that makes it more attractive for the next person to adopt. And that's why that tipping point of car markets is starting to cascade around the world, and we've seen the Chinese market tip and several other markets tip. So that's good news because at some point it becomes cheaper to make the EV than the petrol diesel car, and then it's going to be cheaper to buy everywhere. And even the most um resistant nations or policymakers, people will consume the the cheaper, better technology. In the energy revolution over in Australia, as you've all witnessed the people get hold of solar panels for their roofs of their houses, people like energy autonomy, cheap, essentially free electricity once you've installed the panels, and then you can hook it up to the now super cheap battery that you might stick in the garage or in your EV that you might plug in. In the global context, it's the same story that the more solar panels or wind turbines that have got made, the cheaper and the better they've got. In the case of solar panels, it's just spectacular. Every doubling of the installed capacity worldwide reduces the price by 25% and has done that, has done that for the last nearly about 50 years, and and that continues, and it means now we have the cheapest electricity ever, and it's continuing to get cheaper. And that's that solar revolution means that there are people, particularly in sub-Saharan Africa, about 600 million of them, who haven't ever had access to electricity, who are starting to get it now for the first time in the form of a mixture of off-grid solar, battery storage, and a pay-as-you-go tariff. So this is the this is the great level, you might say of the most productive places to uh to make say solar energy are often in the global south. And it's a big bonus on your balance of trade. If you're a poor country, if you stop importing fossil fuels, which cost you a whole lot of money and you generate your power supply in country.
Liz Courtney:That's really exciting. Headlines that we don't always hear, right, Tim. Also in your book, you touch on nature being a climate ally. At the heart of some of these climate solutions, we're seeing countries and cities like Paris scaling up on green zoning, we're seeing cooling zones coming in across um Southeast Asia, we're seeing nature being seen as an important part of mental health for people now and in the future. Do you want to just unpack a little bit about that role of nature as well as a positive tipping point?
Tim Lenton:Absolutely. There's uh it is ultimately in all ways our life support system, nature, the rest of nature. I mean, I consider we are a part of nature. But yeah, both as a source of resilience and adaptation for the climate change we can't avoid, it's important. But also we'll all be we'll all have a sense that we've kind of tipped nature in some cases in a bad way. I mentioned the coral reefs right at the start. There's plenty of other degraded ecosystems, or ones that have just been run over with farming essentially, and most of that is pasture land. It's for raising livestock, or it's for the crops that you're going to feed to the livestock if they're in lots. In fact, 80% of the agricultural land of the world is used to raise livestock. Livestock, 80% to give us 17% of our calories and 37% of our protein. In other words, a spectacularly inefficient way to feed ourselves. And so that's the main thing that's destroying nature in a global sense still, is the fact that on average people want to eat more meat. But we can get into this. That's not people everywhere. In fact, there's several rich nations, including the UK and New Zealand, for example, where measurably people are starting to eat less meat that's better for their health and undoubtedly better for the planet. In the big picture, firstly, we need to turn around that trend that's been driving nature destruction to reclaiming land on which to regenerate nature. And I would argue there's a potential for tipping points in social norms around diet that will be big in liberating the space for nature to be regenerated. And I say that because we know that diet choices are sort of socially contagious, whether they're good ones or bad ones, it is possible for norms to tip just like they did for smoking in restaurants. Then to get more specifically back to nature, we know that when you can take the pressure off nature and you've got a negatively tipped bit of nature, you still have the chance potentially to positively tip its recovery. If you work with the feedbacks that are in nature, then it's full of its own amplifiers that can create good change. And I write about several examples of this, like smallholder farmers in East Africa planting trees on the land and then seeing greening of the wider landscape. But also simple stuff like somebody kills the last wolf in Yellowstone National Park, the whole ecosystem changes. But when conservationists win the battle to put wolves back, suddenly they get back control over the elk population and the other herbivores that have eaten down all the tree saplings. So suddenly the forests are bouncing back at record rates. I believe and I evidence how we could have positive tipping points of nature regeneration. We need to have our own social positive tipping points, just take off the big pressures on nature loss. But yeah, we have to learn to work with the feedbacks that are in nature.
Loreto Gutierrez:One of the other sectors that you mentioned in your book is transport. And you already covered um quite a bit of it through the discussion around EVs. But I'm curious um whether there are some other surprising positive stories, perhaps, in the shipping sector or maybe in aviation that we may not have heard of yet.
Tim Lenton:Yeah, so imagine this. We're gonna have a renewable energy future, we're gonna try and electrify every activity we can, but there are some things that are quite hard to electrify. If you want to move a large mass a long distance on a ship, just doing that off electricity and a battery is gonna be a challenge. Equally, if you want a lot of thrust to fly through the air in a in an airplane in an airplane with loads of people on board, it's challenging. Or if you want to make um steel, you need a lot of heat. Um, what are you gonna do? Well, for all of those things, there's an option which involves creating what gets called in the tech language green hydrogen. It it just means we've made hydrogen by splitting water in a process that we've known about for well over a century called electrolysis. But we use renewable electricity to split the water, to split the hydrogen off the oxygen in the H2O. Green hydrogen is something we can then use sometimes directly as a fuel, and we can use it directly to reduce iron ore ore that's oxidized down to the elemental form of iron to make steel, which is great, because then we can make steel in an elect in an electric arc furnace that's powered by renewable electricity, so we can get zero emissions of steel. That's a big deal. That's 7% of greenhouse gas emissions just from the steel sector that can go to zero. Great. But then let's go back to the shipping or um how are we going to power the ships? Well, you can take the green hydrogen, you combine it with nitrogen, you separated from the air in a famous process called the harbour bosch process to make ammonia. And ammonia we usually think of as fertilizer, and indeed we could use that, we call it green ammonia as fertilizer, and that'll be a big deal because that's about three percent of greenhouse gas emissions. We can also use green ammun ammonia as a fuel, including for ships. We're gonna need to retrofit the engine or put in a new engine to run on ammonia rather than bunker fuel, which is what most of them run on, sort of the worst bit of the oil, if you like. But it's eminently doable. And over in Australia, you have a pioneer of this in Andrew Forrest. I think you know him as Twiggy, the man whose um whose Fortescue company has some of the biggest mines in the Pilboro for iron ore, but he's been a pioneer, and the Fortescue have been pioneers in retrofitting a a ship to show that it can run on green ammonia, making sure to lobby and pressure the International Maritime Organization to make sure that they allow that as a clean as a clean green fuel. And it has a bunch of other benefits apart from just being um zero emissions fuel for shipping. You're also taking away the horrible sooty rubbish emissions that come from burning running a ship on bunker fuel, which still kill a lot of people in port cities around the world. So there's a big there's a big opportunity space in what we call this green hydrogen economy, and it also could ultimately extend to airplanes because you can make synthetic jet fuel. You can combine green hydrogen with carbon dioxide that you separate that from the air and you make methanol, it's called as a building block to then synthesize a whole bunch of fuels that could include jet fuel. And the good news there is this synthetic jet fuel doesn't produce the little high clouds, we call them contrails, the white streaks you'll see from the aeroplane as it goes across the sky, which is at the moment roughly doubling the warming effect from the greenhouse gases coming out the engine of the aeroplane. There's a whole exciting space of innovation there that can essentially decarbonize or get to zero emissions, a bunch of the activities that we can't just electrify.
Liz Courtney:I think that's been really exciting to hear the perspective on flipping the script and really starting to lean into those positive tipping points that are actually happening around the world. And also for the listener to know that those things are happening. We've got certain goals to hit by 2030 and 2035. If there were like three or five things that we really must need to do to really propel and accelerate these positive tipping points and give us the best shot for the future world and for future generations, how would you summarize that?
Tim Lenton:We can think about that either in the bottom-up way of what can we do as consumers or individuals or as part of a business. And also we can think about it in the top-down way. What policies and regulations do we want to see our leaders um promote and stick to? Let's maybe start on the top-down, even though my message is one that we have enormous power from the bottom-up. It's pretty simple what the most effective policies are to bring forward positive tipping points, because it's all about um activating the amplifiers that are within a system. I talked about how price will come down through economies of scale the more we deploy something, and quality and performance will go up through learning by doing the more we deploy it. What we really need are policies that mandate the phase out of the fossil fuel technology and the phase in of the clean technology. By which I mean things like you are not going to be able to sell a petrol or diesel car in our market after 2030 or 2035, which are like the UK and European targets. What that does is force the hand of the automotive industry to seize the opportunity to get over the initial hunt, which is I'm going to have to retool my production lines for batteries and EVs rather than what I was doing before. But I know that I'm going to make at least as much or more money in that. I just need to know that the policy is set, and then I'm going to realise all the all the benefits of the declining price improving quality as I as I go for it in this new technology path. But business needs to know and to believe that policy is setting clear phase-in, phase outs and is not going to waver at some point in the future. And you might say, well, that's great, Tim. How do we ensure that policy doesn't waver? And I'd say that we all, whether it with our business voice and lobbying or with individual consumer or voting voice, we make it clear in whatever way we can that we support that. Because surveys around the world show that eight, eight, eighty percent of people think there should be more urgent action on climate change and governments should be doing more. So we might be the quiet majority, but we're definitely the majority. Then I would emphasize beyond that key policy message that even in our individual lives, we've got agency to make a difference. We can choose what we eat, we can choose the vehicles and things we move around in. And actually, for most richer consumers, the two of the biggest sources of emissions will be personal transport and food or how we eat. If we are eating rather a lot of meat, and most rich people are eating more meat protein than is healthy for them, and all dietary guidelines would encourage you to eat less meat, especially less beef, has disproportionate benefit, both for the for the emissions, for the climate, for nature, and for your health. Um, and you can enjoy it, by the way. It's it's there are tasty alternatives. And then mobility, maybe we've got to change our car, go for the electric vehicle, the electric scooter, or the electric bike. This is a big part of individual emissions. And the key point is the more of us who adopt the clean option, the more attractive we're making it for other people to adopt. Because we're doing our bit in triggering the innovation that makes it better, cheaper, more accessible.
Dan Leverington:Tim, here at the Green Fix, we're very fortunate to have an instrument that we call the Green Fix magic wand. And so we'd like to give you this magic wand. And we we'd love for you to think about from here to 2035. How would you want to use this wand to accelerate positive climate tipping points?
Tim Lenton:Oh, this isn't this is supreme executive power. I like I like it. Well, without rip being boring and repeating myself, I'd I'd somehow cast the magic wand to write into law the kind of mandates that I just talked about across all some major markets. The good news is we don't need everybody um to be on board in order to get to a sufficient minority for the tipping point to happen and then everybody will change. But we would be great to wield the one to make sure, for example, I think we don't need to China are already on message, but to to m to be phasing in the clean tech and phasing out the old tech. I'd love to perhaps help in use the one to help India commit on the transition and realise the benefits, along with encourage Europe to hold the line. Of course, if it's an all-powerful wand, I would uh dismiss President Trump and reinstate a more sane regime in the US. But maybe it has some some limits to its power. But I think that that kind of sane, just an instigation of sane, progressive policy that's not going to be revocable, would do it do a power of good to activate all the amplifiers and the positive tipping points. I guess my deeper wish is if I could magically tip other people's worldviews to have the pleasure of enjoying and seeing this worldview that's emerged from the sort of science that people like me do that shows us that we're part of this bigger living system that gave us the oxygen atmosphere we breathe and the nice cool equipable climate we're busy ruining, and all the other living things are playing their part in that, but we currently don't value them at all, and in an economic sense, we just run roughshod over them. So I'd at a deeper level, I'd make wave the magic wand so that everybody got what I'd call Gaia and understood our dependence on the rest of life and the need to actually disproportionately value our life support system, and that means rewriting the economic script and re-changing what we value as a society and what we view as as a notion of progress or betterment. That's wonderful. Thank you.
Liz Courtney:That's fantastic, Tim. And on behalf of myself and Dan and Loretta, we firstly want to thank you so much for having the vision and the courage to write a book and giving us a roadmap to solutions with positive tipping points and also reminding us about the power of science and that knowledge that science brings us. I'm sure many people listening also are thinking about either their grandchildren or their children. And we're so grateful that you're helping us with a roadmap for future generations because, in a sense, we're just the the guardians for the future. So thank you for everything that you've done. And you know, kind of encourage people more to read the positive tipping points book that you've done. And thank you again, Tim, for being on the show.
Tim Lenton:Yeah, thanks for having me on the show.
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