In this episode from our archives, Ramanan speaks with Tim Lenton, Professor of Climate Change and Earth System Science at the University of Exeter and Director of the Global Systems Institute.
Lenton has over 20 years of research experience in studying the Earth as a system, and developing and using models to understand its behavior. He is particularly interested in how life has reshaped the planet in the past, and what lessons we can draw from this as we proceed to reshape the planet now.
These topics are covered in his books Earth System Science: A Very Short Introduction (2016) and (with Andrew Watson) Revolutions That Made The Earth (2011). Dr. Lenton leads the University of Exeter’s Climate Change MOOC (Massive Open Online Course), which has attracted over 60,000 learners worldwide since its launch in 2014. He obtained his BA in natural sciences from Robinson College, Cambridge in 1994 and completed his PhD under Andrew Watson at the University of East Anglia in 1998.
In this conversation, they discuss the Gaia hypothesis, tipping points, and human intervention in climate systems. Time stamps and the full transcript are below. This episode is also available on Apple Podcasts and Spotify.
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[00:00:13] Ramanan Raghavendran: Hello, everyone. We're here with Dr. Tim Lenton, and we're very excited about this because we're going to cover subjects that we have not covered in this series and that are important. He is the Professor of Climate Change and Earth Systems Science at the University of Exeter, and Director of the global systems Institute. He has more than two decades of research experience in studying the earth as a system and developing and using models to understand its behavior. He is especially interested in how life has reshaped the planet in the past, and what lessons we can draw from this as we proceed willingly or unwillingly to reshape the planet now. He leads the University of Exeter's climate change MOOC, or massive open online course, which has attracted over 60,000 learners worldwide since its launch in 2014. And as always, we're going to begin with a quick warmup question.
[00:01:07] Tim, could you talk us through your life and career? What sparked your interest in systems theory, and how did you end up where you are now?
[00:01:14] Tim Lenton: I guess I was a geeky teenager. I loved reading Popular Science. I loved the outdoors as well. I went up to University in Cambridge reading natural sciences, and I was very quickly kind of depressed actually, by their version of fragmented science and the idea year that we were being trained to be chemical engineers or something like that. And I came home for my first Christmas quite depressed. And my dad gave me James Lovelock's books on the Gaia hypothesis, as he called it for. And that sort of saved me in a way, because I just immediately connected with these wonderful pieces of popular science writing that explained this view of the earth as a living system, and began to convey how past life had created the conditions for all of us to be flourishing now.
And I knew I wanted, I had the scientific calling in me, but that was where I realized, aged 18, that's what I wanted to study and research when I graduate. And I boldly wrote to the Jim Lovelock and he wrote back and said, oh, why don't you come and see me? And from one thing led to another. So that's what captivated me, and what I committed to when I was still at a formative age. And it meant that I then, as soon as I left being an undergrad, I got straight into research on this fascinating new view of the world, and all the conies and excitement around that, really.
[00:02:39] Ramanan Raghavendran: Could you walk us through the arc of your life after undergrad for a few minutes?
[00:02:44] Tim Lenton: Yeah, so I was lucky, because through that initial connect with Jim Lovelock, I was able to get myself onto a PhD with a guy called Andy Watson, one of Jim's former students, and able to start working straight into big questions. They were questions about, how is the oxygen content of the atmosphere stabilized or regulated, and what's the role of life in that? How is the nutrient balance of the ocean stabilized and regulated, and what are those little fighter plankton in the ocean doing to regulate their own chemical world? And that was a brilliant training, and this is the mid 1990s. This was a brilliant training in systems thinking and modeling.
But at the same time there were a lot of debates and arguments about how on earth could life have evolved to be doing things that are good for all life, when we were taught that it's all about selfish genes and survival of the fittest, and blah, blah, blah. So at the same time I started building with Jim sort of toy models of how could these regulatory systems evolve consistent with natural selection and Darwin's thinking. And that got me connected to some leading evolutionary thinkers. So I was blessed as a young researcher to be learning how to represent this stuff in a computer, but wrestling with a deep theory and trying to bring together a theory of evolution with a theory of what was once called cybernetics or systems thinking.
And then I landed a job after my PhD at a government research lab, where up in Edinburgh, a great place. And I had a great boss who gave me the space to just do my thing as an earth system thinker and bring some repute to the Institute, bless him. So I started, I thought, oh, what should I do? And I started making a model of the carbon cycle, as we call it, and the climate. And again, how is all of that regulated or how are we breaking it at the moment? That was about the year 2000.
And from there we sort of stepped into, okay, that gives us some clues for how thankfully the biosphere is taking up half of the emissions we emit every year, but things could go wrong in that. It could go worse. And maybe we want to build some slightly more sophisticated models. So then we carried on and we got into fancier models in simple terms, but starting to stretch our time horizon out, we were looking at not just what will happen this century, but what's the change we're creating in 1000 years time, or 10,000 years time, how long will this human experiment altering the climate last? What's the tail on that?
And then by the mid 2000s, I probably got my first faculty academic job, University of East Anglia in Norwich, famous for environmental sciences. And I was really getting hooked on this idea of tipping points. Then I was like, I knew there'd been these big tipping points in earth history, which have created a world in which we could flourish. But we were also seeing the evidence around us of accelerating climate change, accelerating the amount of the Greenland ice sheet, the Arctic sea ice. We knew from the Earth's climate record that there were these extraordinary jumps that happened, these abrupt changes. And I just started pulling together an understanding of that, and a map of what we called the tipping elements in the climate, the bits of the climate system that took human activities might tip this century.
And I started working on, could we get any early warning signals that the tipping points were coming? That's kept me going. For the last 10 or 15 years I've tried to keep that research thread alive and develop it. But at the same time I was like, yeah, that's like the horseman of the apocalypse role, but people don't just want know the bad stuff that's coming, charging towards them. We want to know how to get out trouble, and to get out of trouble it becomes to me clear that we need some other kinds of tipping points in society, whether that's part us and behavioral change individually and collectively. And of course there's also, it's a both end with technology change as well.
[00:07:02] Ramanan Raghavendran: Got it. Well, and the only reason I don't want to dig further is we are about to dig further. So I'll launch into the main thread. So you are obviously one of the leading scholars in earth system science, Director of the Global Systems Institute, and also for the public by way of your authorship of the Oxford University Press, very short introduction on earth system science. And as a minor sidebar, can I just say, I love the very short, the very short introductions, I think were designed for people like me. And as we've just discussed, you are a long-time proponent of the Gaia hypothesis. And can we double-click on the Gaia hypothesis? So while it was critiqued when it first came out, some elements are now more broadly accepted.
[00:07:53] Can you peel the onion a little bit and help us understand the intersection between earth system science, the Gaia hypothesis, and how all of that adds to our scientific understanding of our planet and the crisis of climate change?
[00:08:06] Tim Lenton: Absolutely. So the Gaia hypothesis is in some sort of nutshell, the idea that the collective actions of life on the planet are helping to create their own conditions to flourish. And that life is also somehow involved in stabilizing and self-regulating some key planetary properties like the climate or the oxygen content of the atmosphere. There's a subtlety to this, because things sometimes do change over time. And we've gone from a world with no oxygen to a world with 21% oxygen to breathe. But the crux of it is when we look, the proposition is that things change through, we might call punctuated equilibrium. There are long intervals of stability, and then there's a revolutionary change that then creates a new stable regime. And that's how Lovelock began to conceptualize the coupled relationship of life on the planet through its long history. It's something I picked up on.
All of that doesn't sound too controversial, does it? But actually if you're an evolutionary thinker, it's deeply problematic because the perspective of evolutionary thinking is very much, how do individuals, and this might these days be thought of as individual genes, let alone individual organisms, how do they make as many copies of themselves as possible? And the things that make the most descendants or copies of themselves just end up ruling the world. That's the blunt version. And why would making a better climate for everybody help you win the race of evolution, in the sense of making the most offspring? It's not obvious. In fact, it often got misconstrued that Gaia was like a giant argument for altruism on the part of everything.
[00:09:59] Ramanan Raghavendran: And the hypothesis, all that Dawkins began doing much of his writing at the same time. So was there a conflict here?
[00:10:09] Tim Lenton: Yeah. I feel it's to do with the cultural timing as well. If you think about the 1980s in particular as a time of Thatcherism, Reaganism, deregulation of markets, selfish gene fits the zeitgeist pretty well. And Gaia just sounds like some weird, new-age hippie sort of tree-hugging...
[00:10:34] Ramanan Raghavendran: The 60s.
[00:10:35] Tim Lenton: 60s, I don't want to go anywhere near that thing. And so I think it's part cultural, the moment, the timing that a lot of people misread it perhaps, and turned against it. Because Lovelock himself has said, and I would argue that it doesn't work through some kind of giant altruism. And we might debate whether the Gaia name is a good or bad choice, to choose a mythological name that gives it a certain animism. Certainly it makes some scientists and serious people sometimes uncomfortable, but then they forget that they're not having a problem when they talk about, for example, the planetesimal that hit the earth and created the moon. They're quite happy to call that Theia, which is another Greek theological mythological name. They don't get upset about that, but yeah, that's by the by. I think it's the baggage that comes with a methodological name that sometimes makes people worry, this isn't proper science or something. On the other hand, it has a huge benefit if it grips the general public, and they get an intuitive sense of what this different world view is about.
So I should finish and answer the question. And why is that not something, why is that different to an idea of earth system or earth system science? Well, clearly they're close bedfellows, but you could also make the case that to see the earth as a system is just to recognize that the geology, the rocks, the physics, the flow of the ocean and the atmosphere, the chemistry of what makes cloud droplets or cycles the elements, as well as the biology, are all coupled together and they interact, and sometimes there are feedbacks. But it doesn't have to be the case that it ends up with regulation or this particular pattern of punctuated equilibrium. So you could say earth system science has necessarily pins its colors to the mast of there being some fundamental reasons why this system is more persistent over time and self stabilizing. And in that weaker view, you might say, you'd have to infer that you might think it's even more fragile if you didn't think there were, there were regulatory processes or principles at work.
So that somewhat delineates a slight difference, but really the crux of it is a lot of what Lovelock first talked about and presented has become assimilated under the earth system science banner. And we're all happy working under that banner, even if most of my colleagues don't want to be associated with the word Gaia.
[00:13:14] Ramanan Raghavendran: Words do matter. It's very interesting, right. If you'd called it earth system science, perhaps the history of his thinking might have evolved a little differently. But moving along from that. So you touched on feedbacks, which is obviously a huge part of systems thinking. And that brings us to some very interesting, and in some ways, startling research you've done on tipping points. And historically, tipping points have been viewed as very low probability. The IPCC report that's taken on a life of its own, as it always does, that's a separate discussion item for one day. It states that we have... Because they are part of the system, weirdly enough. So they generate their own feedback loops. Anyhow, that's a rabbit hole we can save for later. So that report states we have actually passed some crucial tipping points, rendering many of the effects of climate change irreversible.
[00:14:10] Can you help us understand tipping points, and why their importance has not been well understood?
Tim Lenton: Yeah, so I can see one behind me, but I sometimes use the metaphor of an ordinary chair. Upright is one stable state of the chair, but lying on its back is another stable state. And if you lean back on the chair, you get to this point where a small nudge one way or the other is going to take you [back]. So this is a way of introducing the idea that... I mean, the chair is a simple system, but when you get to complex systems, you also have this property that they can have alternative stables states. And sometimes you get to a condition where a very small change can cause a big difference to the outcome. And that's crucially because in complex systems some shift in the balance of what we call feedbacks is happening. And at the tipping point, damping feedbacks that would've maintained stability have weakened completely, and reinforcing feedbacks that can self propel change are coming to rule what's going on. And so one little change becomes a bigger change, becomes a bigger change.
Now that is something that's true of, you and I as organisms can have tipping points, it's true of major parts of the climate system like ice sheets, large parts of the ocean circulation, monsoons, big biomes like the Amazon coupled to the atmosphere. It's also true of social dynamics sometimes, like mass protest movements, political revolution. All of these under the hood share the same maths or physics, if you like of this principle of the reinforcing feedback suddenly taking over. Now, that's not the norm, as you hint. If it were the norm, I don't think we'd probably be here to talk about it. But it can happen. And of course, we don't have to think too hard to see examples in this human realm of tipping points, like market crashes or sudden changes in the uptake of technologies.
If you look in the earth system or climate realm, if you start to learn a bit about that, it suddenly becomes apparent that actually, oh yes, there are these tipping point changes in the climate. There were ones in and out of ice ages not so long ago, within the last ice age, there were 20 of these abrupt climate change events. They're not as infrequent as maybe we would be conditioned to think, because we've all been educated in this view of a clockwork universe that's very mechanical and linear, and everything is all response is proportional to input. Well, it ain't like that. And so now the challenge becomes to say, okay, well, when and where are the tipping points? What does it take to trigger them? And can you spot them before you get there?
One of my favorite topics, because everybody says, oh, well, tipping points, it's unpredictable. But actually, because they're truly a general behavior, and because by definition they mean that something that was self stabilizing and resisting perturbation is getting weaker, then we can watch a system over time. We can see when it's far from a tipping point, you hit it, it bounces back quickly to where it wants to be. You get towards a tipping point, you hit it, it bounces back slower, because it's losing its resilience, as we like to call it. And that's a crucial early warning signal.
[00:17:50] Ramanan Raghavendran: I mean, just as you were, because you used the example you did, I'm or there are very bright people on Wall Street and financial environments who try and link tipping point math and science to movements in markets. I want to... Go ahead.
[00:18:07] Tim Lenton: Well, they do. And the market is a very unusual system, of course, because the human beings or agents within it are understood to be changing their decisions all the time based on their perceptions and information about what the other agents are doing. So it's a very peculiar system, which may display sometimes this thing that physicists call self-organized criticality. But there are some aspects of market dynamics where these warning signals have been seen, particularly in housing bubbles, which of course a big housing bubble was responsible for the '08, '09 crash. Now that is a classic case where exactly what I described has been shown. So yeah.
[00:18:56] Ramanan Raghavendran: Fascinating. When we go down that thread as we can all our threads for a long time, but I want to move us on to something that's very topical and has been for a while, which is in your book you conclude chapter seven by talking the limits to growth model that researchers in the 1970s put forth. And that seems significant controversy in economics and sociology. And so the question for you is not so much about the controversy directly, but how does the scope of human involvement in our earth's processes in the period of human life here, how does that influence the practice of hard sciences?
[00:19:37] And if I can turn that language into something more specific, how does an earth system scientist approach contemporary debates on human activities like sustainable development?
[00:19:49] Tim Lenton: Well, I have perhaps an unusual take on it. I take the view of if life has done such a fantastic job of not just maintaining itself, but actually flourishing, often in the face of adversity, for about 3.8 billion years, then maybe there are some clues to be learned from the biosphere as to what makes a long and happy life flourishing on this planet.
And they're very... It might seem obvious, but you look at Gaia or the biosphere, you rapidly learn, yet pair yourself with the energy from the sun, whether directly or via the winds or whatever in the renewable energy sense, recycle all the materials you need to flourish, because ultimately on a finite planet, you don't have that much coming in from space and you don't have that much coming in from the inner earth underneath you. We are flourishing because the whole biosphere is flourishing because it's doing an incredible job of recycling all the material stuff it needs and keeping hold of it within the system. And of course that means it's using some of what we call as physicists that free energy from the sun to make the material cycling as efficient as possible. If you contrast it with the human endeavor or project at the moment, we look to be doing a really bad job in comparison. We would get poor grades from Gaia.
And it goes deeper than just energy and materials. Because of course it's also about information and about learning and evolution. So there's a level at which you can say to yourself, what kind of information flows and structures make the biosphere such a robust thing? Well, it doesn't have this hierarchical restriction of information flow that we're so fond of in human institutions. It's what we might call a heterarchy. There's a lot more clever, horizontal ways of exchanging information and learning, if you like. And of course it maintains diversity, and that turns out to be a very useful strategy, if you can call it that, unplanned strategy in the face of unexpected threats. So it has several, if you like, ways in which it can respond and evolve when bad things kick in or unexpected things kick in.
And so that gives a sort of deep time perspective or big history perspective on some of the dimensions that we could learn from. Of course, because there's no precursor for collectively self-aware humans, you can't draw all of the lessons for sustainability from what went before us. We have to layer onto that some careful consideration about, is there something special about us? And if there is, I think it's not that we are conscious, because I'm very confident dolphins are conscious, and arguably octopuses, some other species I could name. But I don't think the dolphins are collectively aware of the impact of all dolphins on the planet in the way that humans are growing self-aware, collectively self-aware.
So I think the challenge we give to ourselves, that I call can we make it, can we make a Gaia 2.0, is can we do self-aware self regulation? Can we become part of a new feedback loop, where we realize that our collective actions are not ultimately good for us or for many other parts of our life support system, and we consciously collectively change the way we do things in society accordingly, and then that alters those actions. Then we've got a whole new kind of self-aware self-regulation. Wouldn't that be cool if we get there?
[00:23:31] Ramanan Raghavendran: Well, it's interesting. It doesn't feel like this most days, but at least some days I feel like we are actually heading in that direction, as the awareness is... And I think of our own actions, whether it's me or Mary or others on our team, and how we've changed our own behavior. There is an awareness that is now filtered in. And Gaia 2.0, the allusion to it is a great entree to our last question. And this is a little hairy, which is in my world of VC and tech, the one Mary and I live in, there's an enormous obsession with the shiniest new thing. And so one shiny new thing is the idea of geo-engineered solutions to climate change. And this relates intimately to our previous question and your response, which is, this is obviously an element of self-awareness, and an ability to interfere directly in the processes that underpin how our planet works.
[00:24:38] Based on your Gaia 2.0 work, how should we think about different kinds of human interventions in climate systems?
I'm constantly complaining about geoengineering, and on occasion, I think to myself, but is that right? That's an intervention, me changing how I live is an intervention, there's an intervention and there's an intervention, you know? So help us think about that.
[00:25:03] Tim Lenton: Yeah. So conceptually, I think what this speaks back to is what is the worldview underneath the proposition like geoengineering, or some other approach? Because I feel some of the hard-line geoengineers haven't kind of got Gaia, or even got system thinking completely. I might be being a little unfair, but I feel like it fits in the old world view the clock world view, that yeah, well, we screwed the climate up, but let's come up with a novel, big-scale solution, [inaudible] the medicine, whatever, that's going to correct this other big mistake we unwittingly made. If you scratch your head on that one a bit, you'll quickly start thinking, hold on, might not this create its own problems? Might it not be a new kind of mistake? Because we haven't thought of all of its unintended consequences.
Oh, and by the way, how do we know how strong to turn on the stratospheric sulfate, aerosol dial or whatever, do we honestly believe our models? Do we honestly think we've got the perfect model that will tell us how hard to turn a dial? Well, no is the honest truth as a specialist scientist in the area. So you could make a spectacular mistake with very potent geoengineering approach, but the deeper mistake might be the work that is still stuck in slightly the wrong worldview. It's a part, of course, question of moral philosophy. It's partly over here in Europe, there's still a rich attraction to this idea of when faced with a medical situation, would you try to tackle the symptoms or would you go back to the root cause of the ailment?
For many of us, we would say the best place to start is go back to the root cause of trouble, try and reduce those greenhouse gases. And if you can't reduce them, okay, you've got to work out some way of drawing the ones that long lived out of to the atmosphere. But you don't let all of that continue and just try and whack on some other novelty untested medical intervention on top of the mess you're already making, it's not going to end well.
So I like to use a slightly different language, because I'm Gaia engineering. There's a way I would describe designing interventions that are going to work with Gaia, or nature, if you prefer, and seek to reestablish stability, balance the climate, the carbon cycle, everything else we need to flourish. But I'd look at that slightly more from the bottom up, like a good Gaia engineering intervention is going to, you're going to start with it and it's going to spread because it's providing the benefits you hoped it would. And hopefully, you've got a regulator in there that if it turned out to do something pathological you hadn't spotted, you can shut it down.
And so as conceptually, to me, it's just a different way of thinking about, yeah, we need to do some stuff. We certainly are going to have to repair some damage we've done. We are going to have to regenerate some of the other bits of the biosphere around us that are our life support system. But maybe you work with them and you work from the bottom up, I think maybe as a first line of approach for me and a far less risky one.
[00:28:36] Ramanan Raghavendran: You've you've given me and Mary, and soon other people who view this a whole new set, a whole new vocabulary to respond to the would-be geoengineers who show up in my life from time to time.
[00:28:51] Tim Lenton: I bet they do, yeah. Good.
[00:28:54] Ramanan Raghavendran: Oh, God. So I want to wrap us up here. This has been fantastic. And I mean, truly fantastic. And I'm deeply grateful. I want to thank you for your time, and we're going to go think about everything you said, and see if we can put some of that into action in our work or home or other components of our lives. Thank you.
[00:29:14] Tim Lenton: Thanks for having me. Great.