The most important yet misunderstood concept in climate science - Tim Lenton

So what I'm saying is that we only flourish on this planet because of the circular metabolism, because of life, cycling, everything it needs. So we've got to be concerned with that process if we've got any sense of self preservation of survival. we are looking at the world through the wrong eyes or with the wrong worldview anyway, because we've grown up in a culture that has been telling itself that the world and the universe is a big clockwork machine where the response you get is kind of propo

rtional to the input you give it. That, I believe, is basically a delusion. Hello everyone, and welcome to the Circular Metabolism Podcast, the bi weekly meeting where we have in-depth discussions with researchers, policymakers and practitioners to better understand the metabolism of our societies, or in other words, their resource use and pollution emissions and how to reduce them in a systemic socially just and context specific way. Today, we will talk about an essential concept to understand

our ecological crisis. Tipping points. In fact, several climate tipping points, including ice loss both in Greenland and Antarctica, the slowdown of the Atlantic circulation and more are dangerously close, and risk triggering a tipping cascade. to understand these risks and how to keep us in a safe space through positive tipping points. I have the great pleasure to welcome Professor Tim Lenton. Tim is chair in Climate Change and Earth Systems Science at the University of Exeter. In this discussi

on, we’ll cover: how to understand Earth as a system. the different types of feedback loops and cycles, the different types of tipping points from ecological ones to socio ecological ones, as well as early warning signals for climate and socio ecological tipping points. so with all that being said, Tim, thanks so much for being here and welcome to the podcast. thanks for bringing me onto the podcast Aristide. That's great. Yes, there is this topic of tipping points, which I am so excited to disc

uss. Of course, you have just written - or edited - a major report on this and you have published many articles on this. Before we get to tipping points, I think we just need a short introduction perhaps of how did you get into biogeochemistry modeling and understanding that the Earth as a system. I mean, what was a bit your passion with this? because this has turned into your career right? I was an 18 year old kid. Had gone up to Cambridge University to study the natural sciences because I was

passionate about science. Read avidly as a teenager. I was a bit disillusioned with my degree, if I'm honest. But I after at university, my dad gave me James Lovelock's books on Gaia, a new look at Life on Earth. And I was captivated by that. It was just like my calling. I thought “Yeah, that's what I want to research”. So I wrote to James and said “Look, I'd love to research this and study this and help you out when I graduate.” And he wrote back saying “Great, come visit and have chat” And

it sort of started from there, really. Yeah. So I was very lucky. I was 19 when I met my kind of scientific mentor if you like, James Lovelock. And when I graduated my degree, I went straight into my Ph.D. studies trying to work on “Gaia”, as he called it. Understand how life has evolved in regulating the cycling and the concentrations of nitrogen and phosphorus in the ocean. Oxygen in the atmosphere. And it's just gone on from there. And I've always been passionate about trying to understand t

he earth as a living system and then kind of explain that new scientific worldview to my students or to anybody else who's interested, because it's like a world view. We desperately need that shift in worldview now. yeah, I mean, it's a long journey always. But if you study how life has transformed the planet in the past and how the Earth has gone through the occasional tumultuous change that actually got us to where we are now, interspersing long periods of time of relative stability and calmne

ss, then you kind of appreciate that when we evolve and the way we have, when we start hitting the Earth-system hard, with our greenhouse gas emissions and all the rest of it, then you have a keen sense already. Well, I know the Earth is ... Or bits of the Earth and the climate have tipped in the past. It seems intuitive that we could tip them again now, so better start studying that. And so that's what I was doing. But... You know, by the late 1990s onwards really, I suddenly thought, I really

must have a careful look at that. Yeah. I think it's fascinating. You already use some terms. I think that we might need to to define a bit better. So you talked about circulation of flows, you talked about nitrogen. You talk about the earth as a system. I think when we talk about tipping points, there is a certain grammar or vocabulary or jargon that we need to define for the listeners or the viewers. So for instance, when we talk about the system, we have to define this system, right? That we'

re studying. We define it both in spatial scope, temporal scope, we define what are the feedback loops, what are the flows that we are studying within this massive system, especially when it's earth, right? So perhaps can you help us, by a small example explain us what is this Earth system? Right? What do we study when we look at Earth as a system? Well we study the thin film of life and, and the gas envelope of the atmosphere and the liquid envelope of the ocean and the organic matter, the soil

s and maybe the very top of the crust of the earth, but the realm that some would call the biosphere as well, which is the realm that supports life. And then to my definition, that is the system of earth system science. There's another earth underneath that that's powered by the heat of internal radioactive decay, and also the heat that's still left over from when the earth was formed. And it's smashed together as bits of rock colliding under gravity. And that heat is what drives the the mantle,

circulation and so on and so forth. But that's like those are like in my eyes, two systems and it's the surface earth system. If you want to call it that, bounded at the top by outer space and with a slightly fuzzy and a boundary somewhere, depending on the timescale, somewhere between the Earth's crust and the top of the bottom of the Earth's crust. That's the system that we need to be concerned with. If we're concerned with our own life support system, what makes this such a remarkable planet

for life a real anomaly. We don't know how much of an anomaly, but clearly a very, very special place and a place where life has profoundly reshaped the conditions for its own flourishing. Meaning: life is principally responsible for cycling all the elements it needs to flourish to build its bodies, if you like. And I did mention a couple of those as well. That's the relevant Earth system. And within that, we would probably define something we call the climate system, which would just be a way

of referring to the bits... also the long term mean temperature and conditions of the climate at the surface of the earth. So, that shifts the emphasis a little bit more maybe to the to the atmosphere of the ocean, to particular elements like and particularly the gases like carbon dioxide and methane as gases, and their cycling and maybe it places less emphasis on the cycling of another element like nitrogen. or phosphorus for example. We dont ‘t think of phosphorous as being particularly heavil

y connected into the climate part of the system, although as usual, there's always some connection. So yeah, the climate system is essentially a subsystem of the living earth system. And within the climate system we could then define some other subsystems of that, by which I mean: an ice sheet like the one on Greenland or Western Antarctica is a system in itself, and it's also a subsystem within the larger climate system because it's kind of affected by the climate and has some effect on the cli

mate. So it's kind of Russian dolls of systems and subsystems you look at the circulation of these dolls and sub dolls of how all of them interconnect and make each other function? That’s right. It's like... philosophers have fancy words for it : “ontology” but like when you're looking at the world, you could take an “object” or a “thing” view of the world and then you would label things like “ice sheets” or trees or what happens in rain forest. Or you could take a process based philosophy an

d you can say, “well, actually maybe the processes are the primary thing” and maybe it's actually the cycles and the flows of nitrogen or water that are more the primary thing we should focus on. Of course there are both and mostly in Western philosophy, we've opted for the “thing approach” the object approach over the process philosophy. But the kind of science that I do speaks to... certainly putting a bit more emphasis on a process based view of the world because it's the processes that keep

the world stable or propel instability. And we are, of course, in a time of change. I think we can all agree on that. And change is a process. So for those reasons I play a sort of I have to weave both threads. the object or the process view. And it's just like you and I asking, you know, what does it mean to be alive? Well, that's really a process thing, isn't it? Because tragically sometimes things die, but nothing has apparently changed from one moment to the next. But everything has changed.

So in an object sense, nothing has changed. A process sense something just changed profoundly. this is extremely interesting because of course you mentioned if it's a process, there are dynamics within the process. So you talk about stability change and of course we're going to come later to tipping points. There is this notion of what is too much, what is too little in terms of speed, in terms of magnitude, in terms of many different things. And of course, these are also the different vital si

gns What is a vital sign in these circulations? What is the pulse that you're measuring? First things first. Why do we care about cycles or what we might call the circular metabolism of the planet? Well, this is essential to our life support. So it's probably not widely known that if you take an essential element for life like phosphorus, though, this is an element that is essential to the molecules in us that carry energy. It's also essential to the nucleic acids that carry information in takin

g on it like phosphorus. And you look at the amount of phosphorus that comes into the earth as a system and the amount that might go out into the rocks, if you like. So it might come in from volcanic processes, it might go out. And new rocks is tiny compared to the amount of phosphorus that cycling around, around in ecosystems and in the whole biosphere, by which I mean any estimate phosphorus will go round around your typical, say, forest ecosystem. Maybe 40 or 50 times before it's lost. So wha

t I'm saying is this that we only flourish on this planet because of the circular metabolism, because of life, cycling, everything it needs. So we've got to be concerned with that process if we've got any sense of self preservation of survival. We also realize, we've got this thing, the climate, and we appear to be knocking it out of whack. As my late friend Bruno Latour puts it. And that tells us that hold on a minute. If we're knocking it out of whack something was keeping it stable before, ho

w does that happen? And that then speaks to a number of things. It speaks to what you mentioned, this word “feedback” that sometimes that a complex system like the earth or the climate a change happens, but then within the system comes back a response that can sometimes dump initial change and thus maintains stability. Occasionally things go the other way. You get it. You cause a change in the system. You get a response from within the system that amplifies the initial change. And then, well, th

at's the other sign or type of feedback that then can be, well, a problem if if it's change that is being propelled away from what we like. So we certainly need to be concerned with that kind of cycle in the sense of a feedback loop. It's a cycle of causality. It's not necessarily a cycle of material stuff, although often material stuff is involved. So yeah, we have the literal cycles of material elements like phosphorus, carbon, these things that we depend on, and then we have the causal cycles

or the causal loops that can either stabilize or distabilize things that we care about. And in that sense, when we when we're talking about the concept we introduced of Planetary boundaries, we're trying to put a label on some of the big ticket things we've got to care about as our life support. Like temperature or the climate, ozone layer, water cycle, nutrient cycles, biodiversity or nature or whatever you want to call it. And planetary boundaries is just very crudely trying to summarize well

, if we push some of these aspects of our life support system too far or too hard, it's going to be bad for us. And there's some kind of point beyond which it's really not sustainable to go. And that's what we were trying to get at in defining a planetary boundary of and that that would then loop us back around to thinking about these other cycle things. yeah let's talk more about that at some as we go through I think what is fascinating is what you just mentioned: this point This point is that

you know, if we push harder, then something either accelerates, decelerates, brakes or something like that. And What is a good threshold? How do we identify it? How do we work with it? Exactly. And a tipping point. My favorite sort of subject is a particular kind of threshold which is made very clear because it's the kind of threshold where you go past it and then you trigger such strong amplification within a system that change becomes self-propelling and you don't have to keep pushing it. The

change just continues. So I often like to encourage people to think about leaning back on their chair because everybody knows you lean back to a certain point on the chair and you get to a point where a little nudge one way or the other is going to overtake you off into a very different state, sprawled on your back on the floor or tip you back upright. And yeah, that's one of those points where the tiny nudge one way or the other then suddenly gets amplified into two different very, very differ

ent outcomes. Now, for some, although not all of the planetary boundaries we identified, I could use this understanding we have of tipping points to be able to ground that notion of a boundary because it begins to become clear, for example, with the ozone hole that opened up or was first discovered when I was not quite a teenager in the 1980s. That was a classic case where there was some of this amplifying stuff going on in the chemistry of how particular compounds got into the stratosphere and

then were that chemical magic or whatever you want to think of it, on the surface of frozen ice particles of what are called polar stratospheric clouds high in the atmosphere, but then we say catalyze the disruption of the ozone layer, which and that word catalysis is that is talking about an amplifier process of the ozone destruction. So that was like a tipping point I'd grown up with in a broader sense of the word, and also one that defined a kind of clear boundary like we within. We don't wan

t an ozone hole we were starting to see the nasty consequences that could have that one is pretty clear. But as you said, we're not talking about a simple system like a chair. We're talking about this beautiful, complex living earth and we don't pretend we understand it perfectly. So we are always talking “probabilities” because we never know perhaps have a perfect foresight of where the tipping points are. But we don't have no, we have some information which is good as well as best. So we're na

vigating with a perfect map. But we don't have no map. We have we have a sort of map with some blurry bits. So yeah, exactly. And it and that that's okay because some information is way better than none. in this tipping points elements, you say that's, you know, you wobble a bit and you can either come back out to a sitting position or fall in your back. Right? So here we have two table states, let's say, which are well-defined. Yeah, How does it work with the Earth system? what is the stable st

ate or is the best state? And when was it this best stable state? And where are we going? This hothouse earth states, you know, have we been in a tipping point for a long time or how does these dynamics work? an easier a better entry to point to take a step down from the global scale and look at what I call the “tipping elements” So, like, I gave a label to the subsystems as the climate system or the earth system that could clearly demonstrate these different stable states. Like you mentioned in

the introduction, the great overturning circulation, the Atlantic Ocean or the Greenland ice sheet or the West Antarctic ice sheet, or the Amazon rainforest. In each of those cases, we got well, various lines of evidence from Earth's past, from models and from kind of theory to to believe that they have different stable states that they can be tipped into and out of. So for each of those, we can then, well, we can look around the Earth as a system and try to identify all those systems that migh

t be tipping elements. And then we can ask ourselves what information do we have about how close they might be to a tipping point, and could we force those systems past the tipping points. And if we could, what would the consequences be? And how big an issue is that and should we do something about it? That's sort of the exercise I've been doing on and off for 20 years and trying to focus in terms of that people to the basic answers. Because even nearly 20 years ago when we were first looking a

t this, it was obvious that there were there are several to be honest, several bits of the climate system that could could be tweaked into another state and that we would really care about the consequences. And in each case, we know what's at the core of this. It's that you can get to a point where within a system you go from a situation where there were these damping feedbacks that maintain the status quo, like preserving the ice sheets of Greenland. But if you were forcing it to melt, you shif

ted the balance of feedback and you could trigger a self-propelled amplifying feedback. In that case, you get to a point where as the sea surface drops an altitude that moves into warmer air, which melts things further and at some point you get a tipping point where that becomes what we call runaway feedback. Well, we would I've been busy cataloging all the bits of the planet for which, yeah, there's credible reason to think you had the alternative stable state that existed and you could reach t

his tipping point of a self propelling change. And the the hard that is to try to work out how near that tipping point is. But we have ways of doing the imperfect we're getting a clue getting a clue that maybe we can talk about more. But in essence, If you think about the example, of leaning back on the ten year balance point, you know that when you near the balance point, things are actually a bit more sluggish. The sort of the things that tend to move around so fast near the balance point. And

there's a more general thing that as a system approaches a tipping point, the things that gave it resilience. That's a popular word. The things that were the damping feedbacks that try to maintain the original state or status quo, they're getting weaker. And so whenever you get to a tipping point, the more sluggish a system becomes because you hit it, but it can't recover. It wants to recover, but it can't recover as effectively. And we look for that signal is slowing down and also increasing v

ariability. We'll go along with that in the system as a kind of clue. The tipping point may be approaching and we can we try to do that as best we can across all of these tipping elements. But you rightly asked: well how does that all add up? Because at some point even if we try to be, I might say, reductionist and identify these separate systems that could tip we then quickly realize, well, they're coupled together and actually, if you tip one thing, it can sometimes make tipping another more l

ikely. So if things are wired up like that, you realize, well, eventually that might the consequences of one tipping element tipping another, tipping another... it become they become very global and they have many ramifications. That's where we can start to talk about. Well, you mentioned a hothouse, so I actually think a wet house, if you can call it that, is is the is the more worrying or the more likely kind of global tipping point. Because of rising waters and also... rising sea level, preci

sely that we could tip a kind of coupled loss of the ice sheets of both poles and it might unfold by human terms relatively slowly but quite irreversibly and lead into the wet house. Equally, we could fundamentally reorganize the circulation of the ocean and thus the circulation of the atmosphere in the whole climate. Now that does not have to necessarily translate into amplifying the global warming or the global temperature change. It would still be an absolute catastrophe because if, as has ha

ppened in earth’s past if you reorganize the circulation of the atlantic ocean and you thus break the monsoon in West Africa and India and disrupted in South America and and all the other monsoons, well, given where people live and how much they depend on the monsoons, we're all going to feel that as a catastrophe. Yeah. So I'm not sure which with the that's not wet house so I have to give that a snappy name. I have to think of one, but it's kind of is certainly catastrophe House Earth even if

it isn't hothouse. Yeah. share. I think it's in in your paper called The Climate Tipping Points. you have listed nine of them. You have the Amazon rainforest, the Arctic sea ice, the Atlantic circulation, boreal forest, coral reefs, Greenland ice sheets, permafrost, West Antarctic Ice Sheet and Watkiss Basin. So I think over there what's important, you mentioned some impacts. What happens when we tip you mentioned their link. So there is the domino effect or the cascade effect that one can tip t

o another. And you also mentioned the irreversibility. Some of these we might have already crossed. And it's just these feedback loops that will make, for instance, the Arctic sea ice disappear. Right? So some of them we have already crossed or what is the state here? this is both the beauty of science and the thing that frustrates non-scientists. I think that it's quite hard to be absolutely definitive. We're in one of those times of profound sort of uncertainty. We've got quite a lot of eviden

ce that part of the West Antarctic ice sheet could now be in irreversible retreat. It's some couple of major glaciers draining into the Amundsen Sea that drained a large chunk of the ice sheet, large meaning enough to raise the world's sea levels by over a meter. We can't rule out that one's crossed and we also think from our modeling that when you lose that part of the asset, unfortunately, that destabilizes other parts of the ice. So you might end up losing most of the West Antarctic ice sheet

, which would be about three and a half meters of sea level rise in the long run. And then if we go around to Greenland, it's we know that Greenland is losing ice and accelerating rate We're just not sure if it could lose again about a meter or so sea level rise equivalent. And at that point, a lot of the bits of Greenland that are stuck in the ocean will have gone and you'll be left with the bits of Greenland that are on the land. And then we're not sure whether it will restabilize or whether i

t'll reach a further tipping point where you basically the amount of snowfall is not enough each to balance the amount of melt. And then and then it definitely committed the whole thing to go. And if the whole thing is on the way out, it's another seven meters of sea level rise. So it's hard to rule out that we can't be sure either way. But it's hot. But it's certainly hard to rule out that we might have committed to like ten meter higher sea level in the long run. The long run means it could me

an thousands of years or it could go quicker if we keep warming things up. But ten meters of sea level means if it's already baked in, which we're not sure, it means at some point London, Shanghai, Amsterdam, New York, Boston as some as a bunch of cities, they're going to have to well, they won't be where they are now. Yeah. In the long run. And you're saying, well, thousand years doesn't matter or whatever your ethical position is. But I live in Exeter. It's a Roman city. It's been here the bes

t part of 2000 years. London's the same. So actually, even when I started writing about this 15 years ago, try to say that that I'll be clear about my ethical time horizon. I haven't going to care about things that could unfold even on a thousand year timescale because many of us would identify something about our society that goes back, you know, thousands of years. So why not think about commitments we're making a thousand years hence? I think over here we have a very interesting point because

the irreversibility, I think many of us do not fully understand what does that mean? we often are very good with linear systems and linear responses. But very bad with exponentials, nonlinear responses and all of that. And that also means that once we go, once we have tipped, we will not see again this, you know, these beautiful landscapes, but also these elements that keep us alive in a certain sense. So the 1.5 degrees, not just, well, we missed it, we're going to do better next year. Yes. Th

e worst kind of irreversibility is death, or even maybe worse than that is extinction of a species, for example. You're never going to get it back. But we're talking about, yes, as you put it, like mentally king into that concept that you can make we can collectively make commitments to those things. And even if they haven't gone yet, we're not going to be able to stop them going. So I suppose you could think of it as having this macabre power of being able to collectively create a kind of deat

h for some things that we think are quite normal and might when we thought about it, cherish or might want to preserve like it's the death won't come immediately, certainly not from the sea level rise but it’s still... I find it like a moral proposition to consider us collectively committing well, even the death of London now I think of it, but certainly the death of the a major Ice sheet I'm not saying that the ice sheet as always been there for all the time. Of course it hasn't, but it's been

there for all the time humans have been here, that's for sure. Certainly in the case of the ones we've talked about. And when we go to talk about the species or things like the Amazon rainforest, they've been here a lot longer than we have. And so it is something we really haven't got our brains around in a kind of collective cultural sense. But this is arguably because we are looking at the world with through the wrong eyes or with the wrong worldview anyway, because we've grown up or not, as t

he case may be, in a culture that for 400 years or so has been telling itself that the world and the universe is a big clockwork machine where like the response you get is kind of proportional is the input you give it. And we, I believe, is basically a delusion. But, you know, if we continue to teach our kids that and we continue to adopt an economic framework that is sort of strongly believes in or is connected to that, then well then it's going to take a bit of snapping out of that delusion. B

ut unfortunately, we're also not out of the delusion if we start to see more of that kind of off the scale extremes of the climate that we witnessed in 2023, everybody starts waking up and realizing that, hold on, the output doesn't seem to be proportional to the input here. What's going on yeah. And I think it's very interesting because over here you very much have this ontological versus process approach, right? ontology or a or an object by themselves, but also are part of this circulation hu

mans as well. So yeah, it's, it's very interesting that you introduce that before Yeah, I like the way you asked the question originally, and I sometimes think, yeah, there must have been something you might call a tipping point, perhaps an evolutionary tipping point in the human and coupled to the earth sort of story It's hard to put your finger on it, but it was gosh, we entered the what's called the Anthropocene and we all we entered the great acceleration and we went into this mode of what r

eally appears to be driving in terms of its own destruction. I think the most compelling case is to be made for the switch into persistent economic growth, which some people obviously would celebrate, some of us would have reservations about, and that only really comes with the industrial revolution. Prior to that, there really was a strong damping feedback that you might get a little bit richer, but then you tended to have or have a bit more food production, but then you tended to have more kid

s and you just dilute the gains among all people. And that dumped the thing down. Again, the crux of what the most fundamental change that probably ties back to the origins of capitalism and extractivism and all of it since is the point at which you switch into a long term growth regime. Because as people get richer, instead of thinking, I'll have more kids, I think now we'll have fewer and I'll educate them more. And then you get into this, essentially you get the beginnings of what is being t

hought, what it now a century and a half or so, the so-called long run economic growth, but great as continuing to accelerate escalating cost on our life support system. And everybody knows when they scratch their heads hard enough that that just can't continue. You can't it as people have said for decades, sensible people have said for decades, you cannot continue to grow indefinitely on a finite planet. As K. Boulding was saying: ‘”you need to be either a madman or an economist to believe that

.” And he said that, what was it, 1970? Yeah. Before we switch gears to even more complex elements which would be like socio ecological systems. There is this one last piece that I would like to introduce which are early warning signals. Where do these fit in in this whole tipping point when a system reaches a tipping point as it approaches, what you're saying is the damping feedbacks that maintain the status quo are getting weaker and then some amplifying feedbacks that are about to really take

over and the power chains are getting stronger. So it's like a tug of war or something. Now that's going to give telltale signs because in a complex world, systems are getting kind of nudged all the time by the little changes. And then you can watch how a system responds. And as you approach a tipping point, a system gets less and less good at recovering from the little shocks it might get from the world because the damping feedbacks that want to maintain the status quo are losing their power.

And so that manifests as an intertial system and now it moves further than it did and it struggles to come back. So it slows down in a literal sense of recovery. But the variability, or variance, in the system goes up. So we expect to see this coupled change, in statistical terms increase in the variance. But coupled with something we technically talk about is “correlation in time” or “autocorrelation”, but it's really just saying if a system is slowing down, then at one point in time, like toda

y, it's more like yesterday and tomorrow, be more like today as the system slows down and we can statistically measure that. So we look for those coupled signals as a clue that damping feedback or resilience in our system is getting weaker. That's not a cast iron guarantee that we about here's a tipping point. We what we should do as scientists have other additional reasons to be thinking The system we're looking at could tip. And that evidence can be because it has in the past. For example. Now

then once we've got those ingredients, we think, okay, yeah, this system could tip we look at the data essentially for that it's technically called critical slowing down behavior. We look for those statistical signals and of late, other groups have been getting stuck into this as well. We've begun to get confident enough in the method and have enough data to be able to see that we can look at, say, the Amazon rainforest from space, from from satellites, from the actually, including from the Int

ernational Space Station. And we're looking at things like the fluctuation of the moisture content of the forest, which kind of, if it's a massive the biomass of the forest fluctuates, the moisture content fluctuates as well. We can look at something like that and we can see, “oh no !” those fluctuations are slowing down over the last 20 years. It doesn't mean we've arrived to a tipping point, but it means the system is losing resilience. That's that's a worry. And that's just one of many examp

les where we start to see this as possible. And it gives us extra information about what's going on and where we're supposed to raise the alarm bells. Yeah. So more points in your map I guess to to read your direction. so I'd like to picture brings about socio ecological systems and how can we apply tipping points within these because as if ecological systems were easy enough and not complex enough, if you add the strata layer of humans that are completely non logical human beings and organize i

nto societies and interact with these ecological systems, you know, there is this famous element that says that there are some social tipping points. If more than 25% of population adopt a certain behavior, then we are we have this cultural tipping point. How do you approach, you know, territorial or socio ecological systems with this, with the glasses, you already have? I tend to first of all, look at it through the feedback glasses because I know at some deep level and you could say it's a mat

hematical level and in this case you're going to have to buy into the view that there are some sort of laws of nature essentially. all of us as scientists have kind of signed up to that. But I would go to the social that the message is social ecological systems through the same lens as a feedback. And so do we have can we have or do we have a situation where the balance of feedback in this now even more complex system with the people in it could shift and the amplifier feedback that can exist in

these systems, Can it get to a point where it's strong enough, where it becomes self propelling, which is by my definition, a tipping point How do I go about that? Well, I would look, I do the same I do for the planet or the climate. You look into history and you say, yeah, there are some apparent tipping points here. There are these political protests that turn into violent or nonviolent revolutions, which then fundamentally change the trajectory of a nation or, we went we went from horse draw

n carriages to cars in a decade, and the US cities throughout the 20th century or a bunch of other examples. And then I then you ask yourself why? I ask myself, okay, this is interesting. What are the reinforcing feedbacks that can bring it that are behind these tipping point changes? Well, protests, political revolutions are a classic example. first person to protest is very brave. So they're putting their life on the line, sometimes only. But they, crucially, by changing what's called the publ

ic, is stated preference. They're making it incrementally easier for the next person to break from social norms, as they're called, and and join them in the protest. Who makes it incrementally easier for the next. So on and so on. And sometimes that reinforcing feedback can get it can get strong enough to cause exponential growth. So propelling change, as we all saw with the climate protest movement and as we've all seen in history with other examples. And then then you discover, well, that's ju

st one case of a sort of social contagion dynamics that can apply to other things like a bank run, as they're famously called when you know. So as soon as some people start thinking, I'm not sure the banks a safe place for my money, I better queue up to get my money out. Other people start going, my God, they're worried about the banks being insolvent. That's taken their money. I'd better go and take my money out. And then that and so on. Right. So it's obvious that those ones are tipping points

and strongly reinforcing feedback technology is really interesting in our relationship with it, but it's not hard to dig around and learn a bit about those fields and realize, yeah, actually the people there are specialists on what's called diffusion of innovation. I've been saying for over 60, 70 years that, hey, there's a common pattern here that new innovations, suddenly some they take off exponentially in their uptake and that there's a bunch of stuff usually going on there. It's partly bec

ause people seem times they're imitating what other people do and taking up the in this case of technology or behavior. So it's very pure social contagion. It gets cold. But also the more we make something, if it's a if it's a technology, the better we get. It makes it so the more attractive it becomes to us to to adopt it. But also the more we make something, usually the cheaper it gets to make economies of scale, we call it. And that's a reinforcing feedback as well. Now all these reinforcing

feedback, sometimes going in the melting pot together to together become strong enough to give you the tipping point like, like coastal carriages, two cars or something like that, or, or at the moment it's like petrol, diesel cars or electric cars. So these are some of the positive tipping points that you call them ? Yeah. So then my basic argument is, well, look at the evidence that we’re crossing... We're starting to cross the bad climate tipping points and risking domino effects and things th

at are real genuine, existential risks. And we've left it too late to just incrementally try to tackle climate change and stop all fossil fuel burning and greenhouse gas emissions. That's not going to cut it. So we're not going fast enough. We're doing something to try to act on climate change, but we're going about, I reckon, by my latest estimate, somewhere between seven and ten times to slowly decarbonizing the economy. So we've got to believe we can find some pretty strong amplifier feedback

s that going to amplify the change we need to technology and behavior change to get to to basically stop emitting greenhouse gases and and that means finding and triggering what I call positive tipping points positive because in the in the normative sense, it's a very positive thing to avoid what will either be otherwise be, by my own calculations, the harm to billions of people later this century. So positive in that sense, accepting that every tipping point of behavioral and technological chan

ge will always run the possibilities of losers as well as winners beneficiaries, as well as those who will feel like they suffer from the change. And where where this benefit or suffering from change intersects with people that are already suffering or less well-off. Then there's a political need to stop those cases and well, essentially provide or social safety nets of support for those who might be dis-benefited for something that's for the that we can all agree has to be for the collective go

od to avoid the extraordinary kind of harms that are escalating from climate change. And so these positive tipping points, I think you have identified a couple of them. You mentioned the electrification of vehicles. I did. I mentioned electric vehicles because you just look at the data from Norway in ten years, the market has tipped from to 90% electric vehicle sales in 2023 and globally I would I would argue and my group's analysis would suggest we're very close to, if not past, the kind of glo

bal market tipping point. But we could probably think of it market by market. So a lot of Europe is already, I think, passed the tipping point to electric vehicles. The Chinese market has the US markets a couple of years behind. But the point, the more electric vehicles and the more crucially, the more batteries for electric vehicles that get made, the cheaper the next battery has got to make. And also the bet, the better the next battery. And if it gets and we're near that cost parity tipping p

oint, we've already at the tipping point, the total cost of ownership of an electric vehicle is cheaper than or competitive with a petrol or diesel car in many markets. And we're even getting to the point where the purchase price is the same. Knowing that they're cheaper to run electricity is way cheaper than than petrol or diesel. So that one's underway and it's not a perfect technology, the new technology, but for sure it's way better than the one it's replacing. And then the other really big

one is the power sector. It's electricity generation. It's the tipping point from fossil fuel power, electricity to renewable power. We're really you know, I'm saying in the UK where we in the last ten years of or since 2012, we went to 40% of our power from coal burning to pretty much zero. There's one coal burning power station left in the UK and it's closing in September this year. So in less than nine months time and all that 40% and a little bit more is being taken over by renewables. And a

s hopefully listeners will already know, there's exponential growth of solar power and wind power worldwide. And solar power is they're both coming down in price all the time the more they're deployed. But solar power is coming down in price the fastest. And for that reason, my colleague Femke Nijsse is predicting robustly that, you know, maybe we're already past the tipping point for solar power to have the potential to dominate even by 2050. There's a number of conditions that need to be met f

or that to happen. And it could go faster. But we're already, in a sense, the point where, yeah, those reinforcing feedbacks, the more panels I deploy, the cheaper the next panel gets so strong that the beginning to rule the day or rule the dynamics and even you, for whatever political reasons, think you want to try and preserve the coal burning or the coal mining industry somewhere you might find yourself faced with. In this case you could call them economic forces that are so strong you won't

be able to... I’d to summarize perhaps our discussion about these tipping points. Right. I think for the listener or the viewer, they really need to take home perhaps a message about this dynamic component. Is it going from one state to another? What something that after 20 years or so, still surprises you? Or whenever you say to someone you feel like this is still a blowing your mind, you know about these tipping points are so essential in our everyday life or in our everyday understanding. Yea

h. I mean, I try to pinch myself sometimes when I wake up and realize, on my work, we're right on potentially on the cusp of five big tipping points in the climate to commit ourselves to irreversible and damaging changes like the loss of major ice sheets loss of carbon, frozen soils and so forth. Yet at the same time I pinch myself because we have one “get out of jail” card left and that is the evidence that we're also seeing this self propelling tipping point change happening in our social worl

d and technological world with a much faster than expected exponential growth of some things, things being crucial, things like a renewable power supply, electrification of the activities around us and all arguably of some social and political changes. Although it always seems frustrating, it always seems like, why hasn't it happened? Why hasn't it happened? But there's a lot of evidence that it is starting to happen. And that's what keeps me saying the knowledge that maybe that's a positive tip

ping point, can win could win the race against the the negative climate tipping points. what an existential and nail biting matter here, perhaps... Could you recommend with a movie or a book that you would like to recommend for people to inspire themselves or continue the discussion? Of course, you had the discussion that inspired you to become a researcher. yeah. I would have to say if you've never read it, you have to read James Lovelock Gaia and you look at life on Earth of 1979, I think he f

irst published it that book changed my life. So did the next book. You write The Ages of Gaia, a biography of Living Earth, in fact, the second one is for me, better than the first. They changed my life, so they might change yours if you've not read them. Well fantastic. There you go everyone you have more to read and to understand after that Many thanks Tim for our discussion it was lovely