A Sustainable Future
Prof. Adam Sobel, Columbia University, on the Social Responsibility of Climate Scientists

 

Where are the tensions in the climate science community driving research and real-world policy impact? Listen to Jason Mitchell discuss with Professor Adam Sobel, Columbia University, about what the tropics and wet bulb temperature mean in the context of climate change; how to think about the trade-offs between the applied and theoretical sides of science; and why we need to rethink the social responsibility of climate scientists.

Recording date: 25 March 2024

Professor Adam Sobel

Adam Sobel is Professor at Columbia University’s Lamont-Doherty Earth Observatory and Engineering School. He studies the dynamics of climate and weather phenomena, particularly in the tropics. In recent years he has become particularly interested in understanding the risks to human society from extreme weather events and climate change. He is author or co-author of over 150 peer-reviewed scientific articles; Storm Surge, a book about Hurricane Sandy; and numerous op-eds. He is also host of the Deep Convection podcast.

 

Episode Transcript

Note: This transcription was generated using a combination of speech recognition software and human transcribers and may contain errors. As a part of this process, this transcript has also been edited for clarity.

Jason Mitchell:

Welcome back to the podcast, and I hope everyone is staying well. So this episode is about a couple of things. One part is about the tropics and wet bulb temperatures. If you've read Kim Stanley Robinson's book, "The Ministry of the Future", you'll get a sense from the first couple of chapters at least, fictionally, for the kind of chaos a wet bulb temperature event can potentially create. Another part is a meditation on the tensions in the science community. I'm talking about the tensions between science and citizenship, big science and small science, academic work and public policy, the focus on mitigation versus adaptation. And add to that a discussion about the collective work driving big IPCC model development cycles, weather attribution modelling, and avoiding bias as a scientist in the search for knowledge.

Which is why it's great to have Professor Adam Sobel on the podcast. We talk about what the tropics and what bulb temperatures mean in the context of climate change, how to think about the trade-offs between the applied and theoretical sides of science, and why we need to rethink the social responsibility of climate scientists. Adam is professor at Columbia University's Lamont-Doherty Earth Observatory Engineering School. He studies the dynamics of climate and weather phenomena, particularly in the tropics. In recent years, he's become particularly interested in understanding the risks to human society from extreme weather events and climate change. He's author or co-author of over 150 peer-reviewed scientific articles, a popular book, "Storm Search" about Hurricane Sandy, and numerous op-eds. He's also a host of the Deep Convection podcast, which I highly recommend. Welcome to the podcast, Professor Adam Sobel. It's great to have you here, and thank you for taking the time.

Adam Sobel:

Thanks for having me, Jason. Looking forward to talking.

Jason Mitchell:

I am too. So Adam, I want to lead off with your latest essay in nature titled, "Are We All Doomed? How to Cope With the Daunting Uncertainties of Climate Change." It's a fascinating meditation on climate as both an existential risk and a threat multiplier. One of your conclusions as an atmospheric scientist is to focus on adaptation and not mitigation. How does this reflect current politics? I mean, frankly, when I read the essay, I couldn't help but feel some small degree of pragmatic capitulation to the politicisation of climate change and generally speaking, government inaction on climate mitigation.

Adam Sobel:

First of all, I mean a few things to say. First of all I think the government action, though far behind where we should be to avoid the worst impacts of climate change, nonetheless the last few years have seen some big steps forward. I mean we had the Paris Agreement, which for all its limitations, was a big advance over anything before. And I was quite happy when it happened, despite those limitations. And then the Biden administration passing the Inflation Reduction Act, it's the biggest climate law in the US. And various other forms of climate action are happening, so in a way it's an exciting time with a lot more climate action than ever before, it's just that we need much more to actually solve the problem in any kind of satisfactory way. So that's the first thing.

The other thing to say is that, and it's really important that I say this because I'm easily, easily misunderstood on this point. When I describe my focus on adaptation, which you're right about, that is not to say that mitigation is not the most important thing. It is. I mean as I say in the piece, by mitigation what we mean in climate is reducing or cutting to zero carbon emissions, greenhouse gas emissions and the other things that we do to change the climate system. Land surface modifications and so on. Mitigation is like addressing the root cause of the disease, and we have to do that. It's critically important. It's just that we have to adapt too because climate change is not just a future concern anymore, it's already happening and we have to deal with it. It's also the only thing that an individual person or government of a particular country, any individual entity at the scale smaller than the planet can only do so much to mitigate the impacts of climate change on them. And that's adaptation. Mitigation has to be done collectively. Adaptation can be done at many levels.

So it has to happen, it's something that people have more leverage to do on smaller scales than mitigation, thus giving people some agency. But I think more importantly, really my point there is not that we should do adaptation and not mitigation, mitigation is ultimately the big thing we have to do. It's that we have to do adaptation also, and beyond that, as a scientist who over the last years has tried to think, "How can the scientific research that I do be useful to actually addressing the climate problem on the ground?" I have become convinced that, at least with the kind of science I do, which is and to about the carbon cycle but it's about weather and how extreme weather events are related to climate, that I can have more of an impact on adaptation rather than mitigation through my science. Mitigation is a politically constrained thing.

The reason we aren't doing more mitigation than we're doing is political. It's about money and power, and politics. So and I don't think it's limited fundamentally by science. In other words, we know enough to know that we should be doing more mitigation than we're doing, and more information is not, I think in most cases, there may be important exceptions, in most cases going to change that substantially. Whereas for adaptation, I think there's more room for new science to have an impact. And this is a pitch I've been trying to make to my colleagues over the last few years, that adaptation is very diverse activity. It means anything people do anywhere on the planet to deal better with the impacts of climate change. So it involves food, and infrastructure, and health, water, any number of things. And to know how to reduce the harms from climate change on those systems, you need local information, you need to understand how those systems are effected by climate. You need a lot of things where the science is not as well-developed, I think, as in the big picture of global warming.

And so the focus on adaptation is not to say adaptation is more important than mitigation, it is not. It's just where I think I can make a more direct contribution, and scientists like me can make more direct contribution at this particular point in history. And so in a sense you're very right. I wouldn't call it a capitulation to the politics, and I think in individual scientists like me of course can be engaged in the politics through the normal means that citizens can, right? I can vote, I can do activist things, I can go knock on doors for my favourite candidates, and I've done a little bit of that. We can do all of that, give money to your favourite causes. You can do all of that stuff, but as a scientists I think there's more leverage in adaptation. And some of us would like in this time to see our science be used directly to address the kind of problems. So that was my point there.

Jason Mitchell:

That's interesting. Are you an outlier or are other scientists you find, are they sort of aligning or sort of formalising their work around specifically and explicitly adaptation versus mitigation?

Adam Sobel:

I think most climate scientists would not say they're doing either one. Most climate scientists would say they're just trying to understand the climate system. And that there isn't a specific policy orientation to their work. There's many exceptions to that, there's plenty of climate scientists who think about the policy applications of their work. But there's a lot who don't, or at least not explicitly, not day-to-day. I think the dominant paradigm in climate science over the late 20th and early 21st centuries as it's kind of evolved into the thing it is today, is mitigation-focused though, whether people recognise it or not. I mean when I was young, it was somewhat taboo to even talk about adaptation, because if you talked about adaptation it meant that you were giving up on mitigation.

Those days are passed, everybody knows we have to do adaptation as well now. But the organising, the paradigmatic policy application of climate science was, I would argue, the IPCC reports. So the IPCC is this UN body where hundreds of climate scientists from all over the world get together, look at all of the data, and put out a big report that says what is going on with the climate system and how it's projected to change. And the explicit purpose of that is to inform international negotiations on climate, which are mostly about emissions. I mean there's an adaptation part too, but mostly the Paris Agreement is about reducing emissions, for example, and all the UNFCC processes working up to that.

So I think to the extent that most climate scientists thought about their work is relevant. To policy, first of all they didn't think about it that hard, I certainly didn't when I was young. But we would think, "Well, we do our science and it will kind of go into things like the IPCC, if not the IPCC itself, and policy makers will read that and make their decisions." So I just think there was an implicit mitigation orientation there, as well as the fact that adaptation was sort of politically taboo. Now all of that has changed, but I think the structures and habits of climate scientists hasn't changed that much. So when I wrote a paper saying, "Usable climate science is adaptation science." And making the argument that I just made to you, I got a lot of agreement from a lot of people.

But I think our practise as climate scientists has not quite caught up to that. So I think there is a lot of my colleagues, and especially the younger ones who are now thinking this way and want to see their work be practically used, and so there is a recognition that adaptation is a way to see our work be practically used. But I think that's a change that's occurring fairly recently, and we're in a period of rapid change around that, I think.

Jason Mitchell:

I wanted to take a step back and maybe focus on your field. The tropics represent roughly 40% of Earth's surface area and population. So why is studying climate effects and the tropics important versus focusing on, let's say, current systems like the Atlantic Meridional Overturning Circulation? I guess what I'm asking is in what way are the tropics, call it the, "Canary in the coal mine"? How does signals propagate through the tropics?

Adam Sobel:

So first of all I wouldn't want to prioritise studying any part of the planet over any other. It's not like the tropics are more important than the Atlantic Meridional Overturning or something, but they are different in ways that you started to allude to. And I think the two main things that make the tropics different is first of all it's the place where most of the energy is coming into the system. I mean the sun just shines hotter in the tropics. And so that's one difference. And the other difference is that the effects of the planetary rotation are different. The so called Coriolis force that makes storms spin one way in the Northern Hemisphere and the other way in the Southern Hemisphere becomes relatively weak in the tropics, and that makes the tropical climate, and atmosphere, and ocean dynamics different than the higher latitudes.

I think, so a couple things to say, one is that climate change is actually happening the fastest at the poles. I mean the arctic is the region of the most dramatic and rapid warming. So if the canary in the coalmine is where are the changes biggest, then the tropics are not the canary in the coalmine. But I think when it comes to human impacts, the tropics have a lot of people, and because it's already the hottest part of the planet, for the most part, or at least the tropics and subtropics are. The subtropics being a little bit further from the equator where the deserts are and some of the places that are very hot in summer. Those low latitude regions, although the climate change is a little less fast, in terms of degrees of increase per any amount of time in the tropics, nonetheless because they're already hot places, a degree, at least on people, may be more harmful.

So the places of greatest heat stress are the Middle East, South Asia, parts of the African continent, etc. These are hot places, so you make them a little hotter, even though the temperature change is not as great as what's happening in Greenland, nonetheless these were places where there's already considerable heat stress. So that's one thing. I mean the other thing about the tropics, this is a little bit technical, but because of the weaker Coriolis force, because basically the axis of the earth's rotation points through the poles and not through the equator, it means that the tropics temperature changes are fairly uniform. So the tropics kind of warms and cools in sync with itself. For example, in El Niño events, it goes up and down by the way El Niños and La Ninas. And warming is sort of warming the whole tropics together as a unit.

So that has some implications too. It means, for example, that species can't escape heat within the tropics by migrating, unless they migrate out of the tropics. I wrote a paper on this with Solomon Hsiang a while ago, but they can migrate up mountains, that's about it. That's a bit of a technical point too, but those are some things about the tropics. I mean there's fascinating differences in atmosphere and ocean dynamics, and the tropics and higher latitudes, but I don't know if that's what your question was really about. To summarise, it's the canary in the coalmine not in the sense of having the largest climate changes and absolute number of degrees, but in already bing the hottest [inaudible 00:14:27] every additional degree has a big impact.

Jason Mitchell:

It really, really interesting. I mean, this area of focus for you, tropical weather such as cyclones, intra-seasonal variability, precipitation, and obviously severe convection was imagined in Kim Stanley Robinson's novel, "Ministry For The Future." And I think what really stuck out was the first, what was it, four, five or six chapters in that book that described a kind of a wet bulb nightmare, really, that takes place in India where millions die. So from the perspective of a climate scientist yourself, can you talk about the circumstances and conditions for how extreme wet bulb temperature occurs and the dangers that they represent?

Adam Sobel:

Sure, yeah. So wet bulb temperature is a combined measure of temperature and humidity that is thought to measure the real effect of heat and humidity combined on people or animals, or other systems that respond to both temperature and humidity. Basically we cool ourselves by sweating at high temperatures, so high humidity makes it harder and harder for us to cool ourselves by sweating. So if the wet bulb temperature gets above some threshold somewhere in the low thirties of degrees, or maybe 35 degrees, it's thought that human beings can't survive very long in those conditions without external aids like air conditioning or something, because we can't cool ourselves by sweating anymore and so your body can't thermoregulate. Now there is some disagreement about exactly what the number is or whether those thresholds are useful, and there's also disagreement about whether wet bulb is exactly the right measure to characterise the effective humidity.

But broadly speaking, as the planet warms, it also gets more humid, at least in humid climates. And so the wet bulb temperature is an appropriate measure that combines those to think about how humid heat has an impact on people. So yes, I mean events where the wet bulb temperature becomes sufficiently high are becoming more likely as the climate warms, and they have the potential to pose big threats to human health and wellbeing. So Stanley Robinson's book is based on real science, although that was a very extreme event, that's what he's trying to capture there. I should add, because at this year's American Geophysical Union meeting, a big meeting of many scientists from all over the world, or scientists from all over the world, the presidential lecture was given by another great author, Amitav Ghosh, who is a friend of mine. I know Amitav well.

And he specifically critiqued that part of Stanley Robinson's book on the grounds that this notion of an absolute threshold doesn't account for human adaptation and that people in South Asia are better adapted to heat extremes than maybe Europeans are. And so this was an overwrought exaggerated example, which I think has some truth to it. And also that the response of, although you didn't bring it up, the response of people in India in the book to that was unrealistic. And so there's some critique of that particular episode, but it's based in fact in the sense that events where the wet bulb temperature gets sufficiently high are dangerous, and those events are becoming more frequent and more severe. So that part is true.

Jason Mitchell:

It's super, super interesting. In a recent Time's article of yours you wrote that, "We have to learn to be good scientists and good citizens at the same time, and to see those obligations as connected rather than at odds.' I guess beyond your academic work, you've published widely about climate science and particularly climate impacts in the popular media. How do you think about the risks of sharing political opinions while simultaneously maintaining credibility as an impartial scientific researcher? In other words, how can scientists serve as trustworthy, call it brokers of knowledge in this political climate?

Adam Sobel:

It's a great question and it's one that I've struggled with for many years, and surely not only me. I think a few things to say, one is I think it's a myth that scientists can be some kind of pure, objective beings whose political views and personal characteristics have no impact on our science. I mean we're human beings, science is a thing done by human beings, the philosophers, and historians, and sociologists of scientists have proved conclusively that we can't behave independently of our humanity. I think what we can ask of scientists is to try to be as impartial as possible in their interpretation of data. In their drawing of conclusions from evidence. We have to try to detach ourselves from our personal traits. We don't want to look at a bunch of data and see the answer we want to see and say that's the right answer. So I think in that sense it's appropriate to ask scientists to be objective, and that's what our training tries to teach us to do. Not to see conclusions that aren't there, or mislead ourselves about what the data say.

At the same time, there's a lot that we do as scientists that is not that. Choosing the questions we ask in the first place, and how we approach those, and with whom, and where we put up the answers, and how we explain the answers, all those things are human acts. And so we have to accept that. And so I think that the right way to go about this, and this is not to say that it's easy to do, but I think the ideal we should strive for is to be clear in our communications when we're speaking as scientists and when we're speaking as citizens. And some of that is just admitting when you have expertise and when you don't. So I may sometimes write something that has an opinion about how hurricane risk is changing with climate, and there I'm speaking as somebody who knows the literature quite well and has published a lot on the subject and I think I have some claim to authority there.

When I'm speaking about things that are less scientific or that are outside my field, or expressing political opinions, I'm not. I'm just a citizen. And I think it's fine for me to do both of those things, as long as I'm clear, at least implicitly, when I'm doing one and when I'm doing the other. And that's not always easy, but I think that's the ideal we should strive for. I think when it comes to trusted and honest broker, and all of that stuff, I think we have to recognise that this field, climate science has become politicised, not because climate scientists wanted it, but because the science itself has formed the basis for a belief on the part of most of the world that we have to change our energy systems, and we have to change a lot of things about how the world works. And there are powerful people and entities in the world, such as fossil fuel companies for example, that don't like this conclusion, and some governments too.

And so it's become politicised. I mean you can read "Merchants of Doubt" by Naomi Oreskes and Erik Conway, or any number of other books that explain the denial movement. And that's the politicisation of science. So there are some people I can't win over. My point is I can't be a trusted conveyor of information to everyone on the planet, because there are some people who won't accept anything I say before I even say it. They know that I'm a climate scientist from a university in New York City, and that's it. That's disqualifying right away. So I have to accept that, and accept that to some extent, just by the nature of what this debate is in this society, we're always speaking to the converted a little bit.

I mean you can try to win over the people who are ... I mean I think it's important to be as even-handed as possible, and to accept and even try to look for the ways where a truly sceptical person, a person who doesn't necessarily everything told but is open to arguments and evidence, and to some extent to accepting the authority of institutions. Because we can never evaluate all of the evidence ourselves. Nobody knows enough to do that. I mean somebody who is open-minded and willing to listen, I have to be willing to speak to that person, even if they're not going to agree with everything I say. But somebody who is going to reject anything I say out of hand, I have to give up on. So that's kind of how I look at it, and I think I've given up on trying to win over the hardcore deniers, if you want to use that word. Or sceptics, or whatever. People who I can't win over, I have to give up on them. They've given up on me and there's nothing more we can really do.

The people who are open-minded, I have to try to not overstate my case so that I remain as credible as I can be. But I think that because the subject is politicised, and because many of us working this field have strong feelings that our work should contribute to the solution of the problem. And you wouldn't be surprised if this was coming from a doctor, right? A doctor has an opinion about ... Or a medical scientist. Biomedical scientist, has opinions about science but also wants their work to be useful and will have opinions about how that should happen. And you wouldn't object to that. So I think we have to think of ourselves like that. We have to find our way through this maze, recognising that some of the politicisation is out of our control, and that science and citizenship can't really be completely at odds and the myth that they can be, I think is just that, a myth.

Jason Mitchell:

Yeah. You started by saying that others were caught up in this as well, and the name Michael Mann immediately came to mind, and frankly, it was fantastic to see that he won his defamation lawsuit against the two conservative writers. But I'm wondering, is there a cautionary tale there for scientists, and if there is, what is it? Not him specifically, but the mechanisms around the IPCC, the whole effort to communicate and kind of create a narrative around climate change?

Adam Sobel:

The IPCC is actually a fairly conservative, I mean not conservative in the sense of politically conservative, but I mean the IPCC is accused, if anything, of understating things because of so called scientific reticence. There's a nice paper, another Naomi Oreskes reference, but she wrote a paper at some point that scientists choose the route of least drama. I mean in peer review we are trained to understate things, not overstate things. Because you get beat up by reviewers. So I think to the extent that there's a narrative out there that overstates the threat of climate change, and I do think it's possible to overstate it. I mean it's a huge challenge, and terribly scary in the big picture, but it's not going to kill us all tomorrow, and you sometimes do read things that give you the sense that it might. I think to the extent that's out there, it's not really coming from the scientific community.

There may be exceptions, but I think the statements that I would view as too extreme, as too scary, as really doomist in a sense that's counterproductive, I don't think those are by and large coming from the scientific community. The scientific community tends to understate things. So while I think ... Which is to say the extreme messages are coming from the media are for activists or something. None of whom who I think are as a class wrong, but I think there's been some exaggeration at some point. So when I wrote this essay about, "Are we doomed?", you sometimes do meet people who just can't sleep at night because they think the world is going to end soon, and that's an overstatement.

So I guess I don't really see the cautionary tale for scientists. I mean you can always be attacked, there is movement now in the United States in some states, and at the federal level, to suppress speech of various kinds, and we as scientists, like many others, are always at risk of crossing somebody who doesn't want us to say what we're saying. And that's what happened with Mike, although the details of that were from a different time, but it's not to say it couldn't happen today. I just think I don't know what the cautionary tale is. I think we have to say what we think the truth is the best we can say it, and there may be people in certain states or countries who don't feel they have the freedom to say that, but I still do and many of us still do here, and so I ...

Jason Mitchell:

My point was how do you think about framing scientific narratives in research papers versus popular publications? On the one hand, if one emphasises disastrous climate storylines and points of no return, it tends to lead to obviously a sense of despair, anxiety, even paralysis.

Adam Sobel:

Ah, yes.

Jason Mitchell:

On the other hand, it's obviously important. It's critical to convey the grave risks of continued warming so that the stakes are known. I'm kind of thinking back to a good example of this, February 2024 paper called "Physics-Based Early Warning Signal shows That AMOC Is On Tipping Course." So I mean, how do you weigh the merits of that narrative in research versus popular mediums?

Adam Sobel:

This is a really subtle one, and it has partly to do with timescale, and partly to do, I think, with the tension between mitigation and adaptation, and those things are related. So when it comes to mitigation, I mean why do we communicate about climate is the question we could all ask ourselves, those of us who do it. I mean you were talking about scientific objectivity and honest broker stuff. I mean I once saw Gavin Schmidt, the director of The Goddard Institute for Space Studies, which is across the street from me, and affiliated with Columbia. He gave a lecture once where he basically said any scientist who speaks publicly has reasons for doing it that are not scientific. So we shouldn't pretend that there's some sort of pure objectivity, we should be open about what our reasons are, and try to be clear when we're speaking as scientists and when we're speaking as citizens, and have it all out on the table rather than pretending that we're purely objective.

And I think that comes up here. We should ask ourselves, "Why are we communicating and to whom?" And so when you're writing for your peers in a scientific journal, we're trying to advance the knowledge in some narrow way. And it's not to say that there aren't all sorts of preconceptions about the policy, relevance of our work, but that's usually not at the forefront of what we're doing, and so we usually ... When we're writing for our peers we have a shared understanding of things, and you're just taking it one step forward. When you're writing for the public, and I would say that papers in the highest impact journals like Nature and Science are really somewhat aimed at the public. Those journals are part way between the mainstream media and scientists. So I think I would include those as speaking to the public.

Then we have to think about why we're saying it. And I think if the point is to make people grasp the full enormity of the problem, including in the long sweep of time, so thinking out to 2100 and beyond, if we don't do something about emissions pronto, things get pretty scary, more and more so as the decades go by and it becomes an intergenerational thing, and one of the things that's so scary about it is that the carbon stays in the system, effectively forever from human point of view, unless you can remove it artificially.

So when we're trying to motivate people to support climate mitigation, it is appropriate to talk about the scariest stuff, and the further out you go in time, the scarier it gets. And also, the more you talk about the different risks, I mean things that may not happen or may not happen soon, and that we can't pin down the probabilities but they would be bad if they did, so the thermohaline circulation, stopping or big amounts of methane coming out of the permafrost at the bottom of the ocean and suddenly adding much more warming, or huge chunks of the ice sheets falling into the sea and raising sea level by a lot, quickly, these are all things that are probably not going to happen next month or next year, or maybe not even next decade, but in the long term they're there.

And if we think about ourselves as citizens in not just the world today, but who are passing the world down to our children and grandchildren, and so on, then we should talk about all the scariest stuff. If you're talking to somebody who is trying to do adaptation, who's trying to deal with climate change today, so we talk to insurance companies, we talk to NGOs who are doing development finance, if we're talking to states and localities that have to write adaptation plans, they're thinking about the near future and what they can do to mitigate the impacts that are happening today or in the near future. And not to trivialise those, they're substantial, but they're not as substantial as what's going to happen in the future.

So in that case, I think emphasising all the worst stuff that's far in the future may get people to over focus on it and may almost be counter productive, because the people think they're doomed, they're not going to do anything. And really the climate today, although it is different from the historical climate, but it's not nearly as different as it could be, yet. And so I think when we're talking for adaptation, we're talking much shorter term, and we're talking about it in ways that are relevant to pragmatic actions we can take to cope with it on the ground. And so then I think we shouldn't necessarily emphasise the biggest picture, longest term, most extreme things as much because it just isn't as helpful in that context.

So that's where I think the adaptation versus mitigation thing, it's not to say that one is more important than the other, it's just to say that I think as scientists sometimes we could stand to think a little bit more about what we think the policy relevance, or the human application of what we're saying is because it might lead to different framing. In other words, understand our audience in a given situation and act accordingly.

Jason Mitchell:

Can you talk about your views on the current paradigm and culture of climate science? I'm thinking for example, about the relationship between, we just talked about it, but I see IPCC model development cycles and scientific research or the role of funding agencies or the relationship between big science, which is I'd say IPCC driven and internationally coordinated versus little science, which is a more decentralised scientific culture. Is the focus and the resources dedicated to areas like new IPCC models, is it productive or are they producing ultimately diminishing returns?

Adam Sobel:

Yeah, so first of all, let me just say as a personal comment so that the people understand where I'm coming from in this, one of the things that drew me to this field in the first place when I was young is that there was a small science aspect to it. I mean I had a brief period of working in a field closely connected to high energy physics where the papers had hundreds of authors. This was in the early '90s, and I was really turned off by that. And so I really appreciate it about this field that I've been able to work in relatively small groups. I found that much more satisfying, just from a personal point of view.

And climate science has been getting bigger, I mean the teams have been getting bigger, the models take more people to create and update, and manage. Some of the observational programmes are big too, satellite missions and so on. So we are starting to have more and more papers with more and more authors in. And about the IPCC, I mean I think what you're referring to there is that part of the IPCC process, or connected to it, is a big model into comparison project called CMIP, Coupled Model Intercomparison Project, which is where all the big climate model centres of the world run their models together on the same set of simulations.

The inputs are defined to be consistent so that it's apples and apples, and that gives us the projections that go into the IPCC. So you see graphs showing temperature into the future, with different models getting warmer at different rates, and that's coming out of CMIP. And so the model development centres of the world, of which there's three, or maybe there's four now, I'm trying to remember, in the United States that contribute to CMIP. And then there's a whole bunch more in other countries. There's a few dozen. Those modelling centres do get somewhat locked into IPCC cycles. They upgrade their models but then when it's time to do a new bunch of CMIP runs, they have to freeze the model so that when they put out the runs they can say, "This is the model we used." And it's not going to change tomorrow.

And that process has been very powerful. I mean the IPCC for all it's flaws and all the criticism it gets, I think has played a really, really important role in the global climate debate. And the science has supported that. And the CMIP archive, which is the climate model groups put all their data in one place so that, and this started in CMIP three I believe, in the early 2000s so that individual scientists, whether their affiliated with CMIP or not, or any of the insititutions, the data is publicly available and I can get data from all the climate models of the world that participate in CMIP and I can analyse them all together. And that really was transformative for the field because it's a big difference between looking at all the models and looking at one. You can understand the uncertainty and so on much better if you can look at all of them. And so you don't have to know everybody and all the model centres to do that, all the data is centralised.

centralised just to say, CMIP and IPCC have been tremendously important. I think there is a feeling amongst some of my colleagues, and I don't have the strongest views on this, maybe because I'm not at a CMIP modelling centre, although I know many people who are, and I have worked with many of them. So my opinions are not the hottest and heaviest of anyone, but there are people that feel that it's become too big, and too unwieldy. And I think there's two parts of that. One is the science is kind of big and locked into these cycles, and some people feel that it's not nimble enough. Everybody is doing the same thing and we don't need to do as much of it in such a coordinated way. There could be more individual creativity flourishing. Maybe that's true, I certainly like small science. I feel that a little bit. On the other hand, I think that the consensus we have around the big picture of climate change has been built by CMIP and IPCC, and we shouldn't be too quick to reject that.

I think the other part of it though is that there's a feeling that the IPCC reports are not really ... The headline conclusions are not really changing much from one to the next anymore. The language has gotten a little stronger, and the reports have gotten fatter, and the richness of detail has gotten much more, but there's a feeling that the amount of effort that goes into them, both IPCC itself and CMIP, which are different although coupled processes, that it doesn't quite warrant the same level effort and that the world kind of gets the picture now. I mean I can't remember, there was an Onion headline about this at some point like, "Scientists put out a new report saying: Go back and read all of the other damn reports that were the same." There's some truth to that and I think we could stand to keep rethinking, or to maybe start rethinking how we might have a more dynamic process that recognises the current state of the politics, and the science and design something effectively to do that.

But I don't think we want to give up on the UN and that whole process, as troubled as it is, because it's the only truly international process that we have, and I think it has a lot of power. So anyway, I see both sides of that one and I like small science, I would like to see new ideas and everything, but I think you don't want to throw the baby out, so.

Jason Mitchell:

How do you think about the trade-offs between pursuing, I guess questions on the theoretical side versus the applied side, which you have sort of, I gather, been moving closer to? Do you see these two lines of work, are they complementary or tension particularly in your own career?

Adam Sobel:

Yeah, I have definitely moved, when I started in this field I considered myself a theorist. I mean we don't have a schism between theory and experiment as strong as you do in some branches of physics, for example. But I thought of myself as a theorist in the sense that I always try and understand the basic mechanisms that work in the atmosphere in as direct, close to first principle way as possible. And I wasn't so concerned about making explicit predictions, or about putting out products that would be used by anyone outside the scientific community. And that started changing about 10 years ago, after Hurricane Sandy I ended up speaking to the media a lot, and I wrote a book, and that sort of started me on the trajectory that I've been on since, which we've been working with the insurance industry and some NGOs. And I've been thinking a lot about what some in the science and technology studies call 'usable science'.

So I've done some work with my historian colleague, Deborah Cohen at Yale who is a historian who has thought a lot about usable science and what the history of that term is, and what it means, and the different words people have used, and the tension between basic and applied. And she wrote a little history that argued that in the past, basic science sort of has been seen as, maybe still is seen as the highest form of science, and the smartest people get to do it, and applied science is done by lesser beings that just take the conclusions of the basic research and apply it for practical purposes. I don't believe in that, and obviously the way I just framed it suggests that she doesn't either.

I think some people don't like the term basic and applied, they use different terms. But science is oriented towards a particular pragmatic goal that's not just understanding the universe. Yes, that's the direction I've been going over the last 10 years, although I still do both. I think there is a tension between them. I think it would be naive to say there isn't. But I also think they're complementary. I mean I think some of the greatest discoveries have been made, and certainly whatever the small successes of my scientific career that I think I've been most recognised for by my colleagues, have been in the area of basic research and have resulted from being able to change the question. I think that's ... Basic research is sometimes called curiosity driven research. And what it really means is if I'm thinking about a problem, and I can't solve it, or I'm struggling with it, but at some point I realise that there's some other problem I could solve that I hadn't really thought about before, then I can go ahead and solve that one. And that's perfectly fine.

If I publish a paper and my colleagues think it's good, then I've achieved something. Nevermind that I didn't solve the problem I was trying to solve in the first place. To me that's kind of the definition of basic research. I've often described it like ... Whereas applied research is you're trying to do a particular thing, often for a particular person or group of people, and you've said, "Let me try and help you with this problem." And if you don't solve that problem, then you haven't solved that problem. The fact that you solved some other one, they may or may not care.

And so the way I describe it is that it's like if you've ever done orienteering, and I did a lot of this in my youth, where you're trying to find your way through a forest with a map and a compass. And you have somewhere you're trying to get to, but sometimes it's hard to get there because the forest is really thick, or there's a cliff in the way that you can't climb over or something. So you'd take some other route where it's easier, and you might find something else when you do that, but you still won't get to the place you're going.

So basic research is like you're sometimes following the path of least resistance, or maybe greatest curiosity, and you may not get where you thought you were going, but you get somewhere. So the thing I have found is that there is a tension between them, but I think they can be complementary. And I have found that the failing of applied research is that sometimes it gets a little narrow. Sometimes you're trying to do something and it can start to feel a little routine sometimes, or sometimes you just can't solve the problems, those are fairly obvious. I think the problem with basic research is sometimes it chases its own tail. Sometimes our curiosity is not a reliable guide to what's important, or interesting necessarily.

Curiosity is a personality trait like any other, and it's subject to all kinds of foibles. So I may think something is interesting just because my thesis advisor worked on it, or because I worked on it before and there's one problem leads to the next problem, leads to the next problem. And it can go down a path that becomes self-referential and unimportant after a while. And so what I like as a basic researcher about doing applied research is you get a new source of questions. Somebody says to you, "Can you do this for us?" And you think about it and you say, "Maybe not, actually. But I could do this other thing. How about that?" And they may like it or they may not, but the fact that the information is coming from outside of my own mind leads to new questions, and sometimes that can be very stimulating.

So I think there is, and a lot of great 'basic research' has been done when somebody was trying to solve some applied problem that they may or may not then have ever really solved. The guys who found the cosmic microwave background I don't think knew that that's what they were looking for in the beginning. I can't remember what it even was that they were doing, but they were thinking about radio interference for signals going through the atmosphere and then they found something about the early universe, if I'm not mistaken. So I think there are positive interactions between them, and I think scientists that have a chance to do both can often benefit by being both.

Jason Mitchell:

Yeah, it's really interesting. It seems like there's the turn towards policy and governance is, I've got a small sample set of let's say you, of Tim Lenton and Simon Levin on the ecology side, but it seems almost inevitable for scientists studying climate change or nature or certainly attractive. And I guess I'm wondering why is it, how do you think back on this expansion? Was it organic or does it reflect, I guess a larger frustration with the constraints of the science community to drive real world policy change? Or it might be something else? I've heard you on a TedTalk about a midlife crisis.

Adam Sobel:

No, I think the second thing you said, the frustration is very much a part of it. I mean I think frustration with the pace of change, and with the political system, and with the effectiveness of science in causing change. I mean so there definitely has been a change in the course of my career, and I think what I've gone through, I might be a little bit further along down this path than some of my colleagues, but I'm less far along than others. And I think there are many others that are along there with me, and certainly the young ones. But I think the change that has happened, when I was a graduate student, so this is the early to mid '90s, my PhD thesis was related to stratospheric ozone, not global warming. And the ozone hole, if you remember, which I mean it still exists, chlorofluorocarbons-

Jason Mitchell:

CFCs, yeah absolutely.

Adam Sobel:

In refrigerators. Yeah, CFCs, and then HCFCs after those were banned. I mean these are chemicals that humans put in the atmosphere that were chewing up the ozone layer and that caused human health risks and so on. And that was a huge science to policy success story, because the scientists discovered this thing, they figured out what the cause was, and within a few years we had the Montreal Protocol, which banned the bad stuff and it kept getting updated, and more recently we banned HCFCs. So the scientists said, "We have a problem. We should get rid of this bad stuff." And it worked. So now we understand later that the chemical industry got on board with it because they realised they could make substitutes and sell a whole lot more refrigerators and air conditioners. It wasn't totally selfless.

Jason Mitchell:

I think that was specifically DuPont, right?

Adam Sobel:

Yeah, I mean so ... Well I don't know maybe as good as you the roles of individual companies, but I think that's correct, yes.

Jason Mitchell:

Yeah.

Adam Sobel:

So I mean climate, in hindsight, is already a problem because we don't have the substitution of other things for fossil fuels has not been as easy. But my point is that in the '90s there was a justification for a young scientist in this field to think, "I don't really need to think about how my science relates to policy that much." Because the way things work is the scientists do the science, somebody translates that into policy relevant terms, and then the government decision makers look at it and do the right thing. That's the so called linear model of science to policy interface that's now discredited by all the people who study these things. But that's how we sort of imagined it worked. And I think without really thinking about it that consciously, that's what we could've thought at that time. And the Montreal Protocol gave us really concrete reasoning to believe in it in a short term because it had worked in that case.

So I could be justified for thinking, "Just by doing my research I'm doing something about solving the climate problem, and I don't need to think any harder about it because the downstream steps in the chain are not my job, they're somebody else's job. We all have our own role to play and that's my role." The subsequent 30 years show that that really didn't work with global warming. We didn't decarbonize, policy makers repeatedly failed to act, the fossil fuel industry had way too much power over the outcome, et cetera, et cetera. So I think you saw scientists in this field, me and many, many, many others becoming disenchanted with it and thinking, "Jeez, wait a second. What am I really doing here?"

I mean it's fine to just do the science. I think there's value in understanding the world. I'm a teacher, I educate students. I mean I'm not saying that our work is useless, but it clearly wasn't having the impact that we thought it would have in the way we thought it would have it, to the extent that we thought about it consciously at all, which I think a lot of us didn't think about it consciously that much. At least I know I didn't. And from talking to a lot of colleagues on my own podcast, I don't think I'm that unusual. But anyway, so yeah. There was a frustration with that, and thinking, "What can we do?" And I think one answer is we should all be activists, and we should all vote and support the right candidates, and get our message out in the public, and so on.

But the other thing is what is there a way that our science can evolve to become more relevant to actions on the ground, and that's the other part I've been thinking about. But it absolutely is a response to frustration with the way the political system takes up science, or doesn't, and acts on it. Or doesn't and a certain amount of disenchantment, or loss of belief in the naive view that we used to have. We were forced to lose it by observing events in the world.

Jason Mitchell:

I am going to change lanes here, but there have been enormous advances in approaches to extreme weather event attribution and modelling. I'm thinking, for instance, the World Weather Attribution Initiative. This isn't so much a question about the debate around whether attribution and human induced climate change. It's more kind of a question of what are the remaining uncertainties in terms of driving that causal linkage?

Adam Sobel:

Yeah. So when you talk about attribution, and the World Weather Attribution Project, we're talking about the science of saying, "When a given extreme weather event happens, how was that event influenced by climate change? Did the fact that humans have made the climate warmer make that event more likely to occur, or more intense or harmful, given that it did occur? Or so on. So that's what we're talking about here. And that's a science that has evolved during my career. When I was starting out and when there would be an extreme weather event, the reporters would call the scientists and say, "Was this due to climate change?" And the scientists would say, "We can't answer that. Climate change science only tells us about large scale trends. It doesn't tell us about individual weather events."

Now that changed in the early 2000s with the work of Miles Allen at Oxford, and then others that's become World Weather Attribution and other things, where we now try to answer the question as systematically as we can. Because it never completely made sense to say that climate change is changing the probabilities of different types of weather events, for example making a heat wave of any given magnitude more likely, which it does. And yet say, "We can't say anything about any individual event."

Rather we can make statistical statements that say, "Events of this type through science suggest have been influenced in such and such way are more likely or more intense given what we know about climate change and extreme weather." So I guess a few things to say about attribution that I think need to always be said. One is that there's no simple answer about it. I mean in other words, every type of event is different. And we can do attribution better for some kinds of events than others. And broadly speaking it's correlated with how well we understand how that type of event is related to climate change. Or we're also heatwaves are strongly and directly effected by global warming because after everything is warmer, then the probability of exceeding some temperature, however you define a heatwave, becomes greater. And we can do attribution fairly confidently on heatwaves.

Hurricanes less so, because their relationship to climate change is a little bit more complicated. But we can still say somethings about them, and when you get to tornados and winter storms it becomes harder because the way they're related to climate change is even more uncertain. So that's the first thing to say is that it's event specific. The question you were asking is "What are the frontiers of it?" If that was the question?

Jason Mitchell:

Yes, yes.

Adam Sobel:

I think yeah, I guess I want to add a couple more things before trying this one. I think the other thing to say is that I see attribution of individual events, I think that despite what some people might say, the main reason to do attribution is to influence the public conversation in the media. Because, and that's what it's mainly been used for. There was a paper by my colleague [inaudible 00:53:28], a French scientist, who has shown that the main ... This is an oversimplification of her results. But that the main uses of attribution science are the media. And that basically because extreme events get in the media, it's a natural time to talk about climate, and so reporters are calling us so attribution science tries to give the best answer we can when people are paying attention.

My point is that almost the same type of science goes into what I would call risk assessment. But the aim is different. So attribution scientists say ... If I wanted to do risk assessment I could say, "What's the probability of this event occurring? What's the probability of a Hurricane Sandy hitting New York?" For example, and how has that changed since 100 years ago? And how might it change in the future, and what would the impacts be? That's what I would call adaptation science. That's where we say a decision maker who has to understand should they build a sea wall or not, which New York City is doing, wants to know the answer to that.

Attribution asks a slightly different question which is how much has that probability changed, and can we say with confidence how much more likely the event is to happen today than 100 years ago. I might be able to assess the risk pretty well. If the change is small or uncertain, then I might not be able to make a strong attribution statement. But I might still be able to do a risk assessment. And I might even be able to say something about how the risk is changing, because uncertainty is really just part of risk. I mean if I can't tell you by how much the storms are getting stronger, then I can't rule out them getting a lot stronger, then that's part of the risk in some broader conceptual sense.

So it's just to say that I think the short answer would have been the frontier is just understanding better how extreme weather events are related to climate change. And there's plenty to do there. I mean I think for every type of extreme event you can name, there's ways in principle as we make our science better and our models better, and our observational data sets better, and our understanding better, there's ways of narrowing the uncertainties and being able to make clearer attribution statements. Although with some events we might not get there any time soon because of hard problems.

So we can always try and make the science better, but I think that for the broader problem of climate risk assessment, which I would say attribution is a subset of, in that it's closely related in the type of science it is, that a big frontier is characterising the uncertainty in the most decision relevant way. So I would make the argument, and this is getting back to my adaptation science theme again, that when climate scientists are asked, "What do we need to do to help decision makers deal with climate change?" We tend to say we need to make our predictions better. We need to make our models better so our predictions get more accurate, so we reduce the uncertainties. And I certainly agree that we should always be working to do that, and we always are. But that's often a long term project.

The problems we're trying to solve, if they were easy we would've already solved them. The models have gotten better for decades, but some things are stubborn. There's some things that are wrong with them that we know about that have been very hard to fix. And we won't be able to do that by next year. Whereas for some people that have to make decisions today, and this is where it's relevant to adaptation, they can't wait for that. And some fraction of our effort would be better spent, I think, on characterising what we know today, including all of the uncertainties as reliably and realistically as we can because that's part of the risk is what do we know? And what we don't know, and what we don't know can hurt us. And so I think that sort of characterising the knowns, unknowns, and the unknown unknowns and all of that in a way that's relevant to decision makers, I think is a frontier maybe not exactly of attribution, but certainly of risk science which is coupled tightly to attribution.

Jason Mitchell:

So last question. The IRA is a good example of driving private sector investment to finance mitigation and adaptation efforts. But how do you think about the role of markets in addressing climate change? Do you worry about the financialization of climate nature as well?

Adam Sobel:

Yes, I do worry about that. I think this is an important problem and I spend a lot of time thinking about it from different perspectives. I should first of all say I am not an economist. So I can't say anything too sophisticated about markets and how they work, but I think we all understand more or less the basics of it and how the private sector differs from the public. And a few basic things to say. I mean one is that because of the failure in large part of governments, including very much our own in the United States to act sufficiently on cutting greenhouse gas emissions, and the increasing frustration of ever wider segments of the public on that. There's been a push for the private sector to do what it can. And I know you've had plenty of podcast episodes about it. I listened to a couple of really good ones.

And that's great, and admirable, and to be encouraged, but I think the private sector can only do so much on its own. And I've heard some of your guests say this, but to put it very simply, there's a lot of decarbonization that would make sense if there was a real price on carbon set by governments in a way that only governments can, because only governments can legislate and regulate such things in a binding way. And if there's no price on carbon, then it's not as attractive to do various decarbonization measures. And so the attempt at voluntary carbon markets that have crashed recently as people have realised that a lot of the offsets being sold were, if not nonsense, not what they were cracked up to be. That's you see part of the failure of markets there. I mean I just think we need some amount of government action to make private sector ... To galvanise the private sector to use its magic.

The private sector is great at solving a problem if there's a financial incentive to do so. It's not so great at setting the financial intensive in the first place. So I think that's where the private sector can't really do it by itself, as much as we might wish it could. I think the other thing, a more narrow problem that I've spent a lot more time thinking about is the private sectorization of climate information. So an exciting development in the last decade, really not even in less than a decade is the growth of a whole new private sector industry around climate, and part of that is consulting firms, and existing consulting firms and banks and so on adding groups to ... And start ups that are doing what we might call climate risk assessment.

I mean trying to characterise both transition risk and physical risk in a way that can be used by other companies or their own company that wants to decarbonize to reduce their physical climate risk and to help others do the same. And that's great. I mean I have a lot of former students and colleagues working at these companies. And they produce scientific information. They produce models and data sets that will characterise climate risk in various ways. I think that's a super exciting development. I would much rather see the private sector care about climate and try to do something about it than not, but I think a problem with this stuff is that it's first of all, mostly proprietary. So it's for paying customers, and generally not free.

And that obviously limits who can use it. A related problem is that the proprietareness means that the models are generally if not complete black boxes, at least not fully documented and peer reviewed that a government funded scientific work would be, and so it's harder to evaluate how good they are, and to know what the underlying assumptions are. I wouldn't say it's impossible, but it's harder. And I think as we need to have both adaptation and mitigation occurring in the public as well as the private space, I mean a lot of adaptation for example is going to have to be done by state and local governments, and community groups, and so on. We need climate information to be available that is free, that has been subject to the kind of vetting and open debate that only, I think, the academic and government sector can do because we have a mandate to be open about everything, and to debate everything and peer review.

I think we need that not just so that it's free, but the openness is so that people understand limitations and the assumptions. So because for example let's say this kind of climate science is used by the insurance industry now, and I work with a lot of companies in that space and I'm pro private sector, I think insurance is a good thing. It's part of the response to climate change. But we're doing climate science that's supposed to assess how is hurricane risk changing in Florida and the other costal regions of the US affected by hurricanes. That science could be used to influence decisions by governments about how to support people living in high risk areas. So I mean ultimately as sea level rises and as storms get stronger, there's people living in high risk areas that probably won't be able to live there. And the government will have very politically painful decisions about how much to subsidise people living in the places they've been at the expense of others.

And as it becomes too expensive to keep everybody where they are at the low cost they've had for insurance and infrastructure, and if those politically difficult decisions are made on the basis of science that's not open because it was done by private companies with a profit motive to keep their science private, then I think that's a political problem. So that's another way that I worry about the private sectorization. I am not against any of the stuff being done in the private sector, I just think some of it needs to be done in the public sector also. I shouldn't say I'm not against any of it, I probably am against some of it. But I mean I think the private sector engagement on climate is by and large a good thing, I just think there is a lot of ... First of all the government has to set some of the boundary conditions, and also there is tremendous incentive for green washing, and for corporations overstating what they're really doing. And also from a narrower point of view I'm concerned about the openness of information, especially as it influences the public debate on climate adaptation.

Jason Mitchell:

That's a great way to end. It actually brings to mind a previous guest, Madison Condon at Boston University, who's got a paper out called "Climate Services, the Business of Physical Risk". Where she describes this climate intelligence arms race, which you've just very aptly characterised. So completely agree. So it's been fascinating to discuss what the tropics and wet bulb temperatures mean in the context of climate change, how to think about the trade-offs between the applied and theoretical sides of science, and why we need to rethink the social responsibility of climate scientists. So I'd like to really thank you for your time and insights. I'm Jason Mitchell, head of Responsible Investment Research at Man Group here today with Professor Adam Sobel from Columbia University's Lamont Doherty Observatory and Engineering School. Adam, thanks so much for this. It's been fantastic.

Adam Sobel:

A pleasure, thank you, Jason.