JOSH: Hello, and welcome to Clearer Thinking with Spencer Greenberg, the podcast about ideas that matter. I'm Josh Castle, the producer of the podcast, and I'm so glad you've joined us today. In this episode, Spencer speaks with Diana Urge-Vorsatz and Misha Glouberman about forecasting the impact of climate change, the need for research on the long-term compound risks of global warming, and the accessibility of climate research to laypeople.

SPENCER: Diana and Misha, welcome.

MISHA: Hey, Spencer, it's great to be here.

DIANA: Thank you for the invitation.

SPENCER: Today we're talking about a very important topic, which is, how big a deal is climate change. So we're starting with the assumption that we are changing the climate through human activities. And the question is, is this going to destroy the world? Is this going to make the world much worse? Are we going to end up living in a hellscape, or is it just going to make the world a little bit worse? And I think it is a really interesting topic, because we hear from different perspectives, very different views on this. I just want to give a few quotes to start that people may have heard from sources that are commonly read. So I'll start with a quote from AOC, who's a well known US representative. So she says, “Millennials and Gen Z, and all these folks that come after us, are looking up, and we're like the world will end in 12 years if we don't address climate change. And your biggest issue is, how are we going to pay for it?” Here's a quote from Greta Thunberg, “Adults keep saying we owe it to young people to give them hope. But I don't want your hope. I don't want you to be hopeful. I want you to panic, I want you to feel the fear I feel every day. I want you to act. I want you to act as you would in a crisis. I want you to act as if the house is on fire, because it is.” And the final quote is one from The Guardian, “The earth is in a death spiral, it will take radical action to save us.” So here in quotes like this, it's very reasonable that people come away thinking, “Oh my gosh, the world might actually end or if it doesn't end, we might be in absolutely dire straits as a species if we don't get our act together.” And so this kind of thinking got Misha (who's on our podcast today) investigating this topic as a layperson, not as an expert, as a layperson who's just interested in how bad will climate change be. So Misha, I want to start with you. And I want to hear a little bit about the story about how you got into this, and sort how that journey went. So why don't we begin there?

MISHA: Yeah, for sure. I think I was really curious about it, and my assumption had been kind of in keeping with the things that you talk about there, that this is this enormous risk that the wellbeing of our children is in indirect peril, and that kind of thing. I was pretty worried about that. And at the same time, I think I was also beginning to notice how other issues that I knew about were covered in the news and seeing that sometimes how things got written about it, and how I knew them to be were different. And so, I guess, I thought I'd try to do some research and think, maybe a little bit quantitatively, because even those quotes you gave, like, what does that mean? What does it mean, the world is in a death spiral? What does it mean to say the house is on fire? What when I, as a layperson, tried to think quantitatively about risks, a big question for me is like, what are the experts actually saying? And how do we quantify that? Like, is 10% of the world's population going to die, or what are the kinds of risks that we're looking at? And so, I went and tried to find out about that. And it was really confusing. And I ended up doing it, I ended up presenting this presentation at a small conference that a friend of mine put together. So I did sort of a bunch of research. And I was surprised by a few things. I was surprised by how incredibly hard it was to find data that was quantitative. And partly, that it's hard to predict, even for people to put numbers on what ranges of things were possible, how incredibly hard it was to do that. And then also, what was even more surprising to me was that when I did find numbers, the numbers seemed orders of magnitude less bad than what I would have expected. I don't want to go on for too long, but the example that most struck me was that if you just Google how many people are likely to die from climate change, the very first result that comes up, and it comes up a lot — and it really sort of captures the whole thing for me is a page from who I think of as a very credible source. And what the page says is it says — climate change is the greatest risk to face humanity in its history, or something like that. And then it says 250,000 people a year may die from it. And to me, those are contradictory statements, like 250,000 people a year dying is, in the grand scheme of things, terrible. But, it's a real drop in the bucket, right? Six million people a year die from obesity. It's a very, very small number. And so, putting together this sort of qualitative claim that says, “This is the worst thing we've ever faced,” with this quantitative claim that if you look at the numbers seem very tiny. That was the sort of confusion I felt I kept encountering again and again, and I'm still not sure what's going on there. So, that's a long answer to a short question.

SPENCER: That's really helpful. And you're talking to friends of mine who are really interested in environmentalism and work in the space. I just see the fear that they go about their lives with around this. And I was talking to a friend and just sort of asking her, “What do you expect? What do you think life is going to be like in 50 years?” And she was saying, “Well, I think we're gonna have constant natural disasters, that life is just going to be terrible, like it may not be a place we want to live in.” Living everyday with that fear, I think it's a really important topic of like, “Okay, I think we all agree this is a really bad situation. But how bad is ‘really bad'? So, Misha raised this topic to me, and we had some interesting back and forth about it. And then I got in touch with Diana, who is an expert in this topic, who is involved in creating the IPCC report, which is one of the most credible reports on the topic of climate change. And so, Diana, do you wanna tell us just a little bit about your work on climate change and how you come to this topic?

DIANA: Yes, thank you very much, Spencer. And thank you for the invitation. I'm super excited to be talking about this because as I was looking into what Misha has put together, that really made me think twice. So who am I? I'm a professor at the Central European University in the Department of Environmental Sciences and Policy. I'm also Vice Chair in the Intergovernmental Panel on Climate Change in its Working Group 3. Working with 3 is responsible for looking at mitigation, or the solutions to climate change, or reducing climate change, and not the impact, but reducing climate change itself. So as such, I'm contributing a lot to what also Misha has been discussing. And as the Vice Chair, I'm really working with all three working groups, actually. So I work behind the scenes in IPCC, and I get to see how whole science has been cooked, and how our reports are being cooked, and what other people are thinking. And we socialize a lot together. So, I can offer a lot of the insights and feelings from that side. But it was really, really insightful for me to be able to think about what Misha has already described, and in general, to rethink. Why are we worried if the data that comes out to people are completely different?

SPENCER: Yes. So, this is an unusual episode for us, because we've had some episodes where we bring together people who disagree, and we tried to have a really respectful conversation and explore the roots of disagreement. But this is an interesting one, where Misha is playing the role of the interested lay person who's really trying to figure out what's true. And Diana is playing the role of the expert, who has vastly more knowledge than Misha and I are on this topic, and she's gonna be playing the role of helping us navigate this space. So it's gonna be a new podcast format. I'm excited to explore this format. We'll see how it goes. But I think it's gonna be a really interesting discussion.

MISHA: I sort of started off as a curious layperson. And now, I find myself in this slightly uncomfortable place where I'm kind of opinionated. I sort of came in with trying to hold on to a skeleton mindset and be curious, but because I've put so much time into this, I'm finding myself partly having opinions, which is okay. And partly, I'm finding myself inclined to sort of advocate for them a little bit in a way that I'm not sure I'm comfortable with, especially talking to a world expert as a layperson. So, I think it's a complicated thing that we're doing here. And we'll see.

DIANA: Yeah, and if you allow me, I also want to add two things to my short introduction. One thing that I think is also important about me is that I spent most of my life actually staying at home with my kids. I have seven children at the same time while I was working for the IPCC. And this is all voluntary work that we do for the IPCC. So that actually allowed me to have this luxury that I spent so much of my time in IPCC, but that's important. But the other important thing is that even though I'm wearing the IPCC hat in this conversation, whereas I will draw a lot on the IPCC side, I'm not representing the IPCC. So I'm just representing my own personal scientific perspectives, but certainly drawing up on a lot of the knowledge accumulated in the IPCC.

SPENCER: Yeah, thanks for clarifying that. So the place I want to start here is with the Good Judgment Project report, which Misha pointed out to me, basically. Do you want to give us a little background on that? What is the Good Judgment Project? What does that report talk about?

MISHA: On a higher level, the Good Judgment Project is like a group of super forecasters. And what super forecasters to me are a really interesting resource, if you're a layperson trying to make sense of what experts say. And especially, if the experts are saying different things. What super forecasters are is they're people who are experts and who have a proven track record of being able to predict things about the future. And the way that they generally do that is sometimes by being experts, sometimes by being able to judge and aggregate the opinions of different experts. And it's really important to understand that. These groups are groups who have demonstrated through track record and through competitions, basically, that they're better at this than anybody else in the world. So if you look out on some subject, you're like, “Oh, well, this expert says this is going to happen. And that expert says that's going to happen. How do I make sense of this?” Super forecasters are people who are experts in being experts in thinking about experts, basically, and making predictions. And so when I'm trying to understand what to think about a topic, especially with a topic of what's going to happen, one resource that I'm inclined to go to is to look at the super forecasters and see what they do in the aggregate and how they aggregate stuff. And so one source that I found — and again, all this stuff's really hard to find as a lay person, and I found that report incredibly hard to read as a layperson — but I found this report that's just from about six months ago from the Good Judgment Project, which is like the top super forecaster project, as I understand it. And they gave super forecasters a bunch of really very, very technical questions about what's likely to happen in different scenarios around climate change. And it seems to me that if you read those reports that the thing that I see again and again is — if I were to qualitatively summarize, what I think I see when I look at what experts say about climate change is that — it looks something like this. The most likely outcome around climate change is that climate change will be a problem that's kind of bad on the scale of a number of kinds of big problems that we face in the world right now. And examples that I keep coming back to are like obesity, smoking, car accidents, that it'll sort of be a scale on around that kind of scale. Those are really bad things, but they're not the kinds of things for which people don't decide not to have children, for instance. Because there are car accidents in the world, it's not something that destroys civilization. They're bad, but not civilization destroyed. And that there's a not impossible outcome that things will be worse than that, for sure. And also not impossible outcomes that things will be better than that. I don't mean to discount. I think those longtail possibilities are important, but when you look at most of those things, the most likely outcome is that climate change is a problem about that scale. And also that in 50, or 80, or 100 years from now, life on the planet, for most humans, will unbalanced be substantially better than it is now, not worse, because that's the overall trend. So that when you look at what most of the experts say on most issues, what it seems to me to say is that in 80 years from now, if climate change is pretty bad, fewer people will be starving, fewer life expectancies will be longer, there'll be less infant mortality, that by most measures of human wellbeing, most people will be better off including the poorest. They won't be as much better off as they would otherwise be because of climate change. That seems to be the kind of thing that I see. And when we looked at the super forecasters' report, which is the most trusted source that I'd be able to find for me personally, I'm not sure everyone would feel that way. It seemed to me like it bore up those kinds of results so that the results were so technical, that it was a little hard for me to understand them. And Spencer, I'm curious if it looked that way to you.

SPENCER: And I'll be very interested to get Diana's opinion. But let me just say a few things about the super forecaster report. And I'm gonna give you just a brief summary of what it says. So first of all, in the methodology, I think this is interesting. I was gonna read this to generate the most accurate forecasts available. Good Judgment works with some 180 super forecasters from around the world, whose forecasting accuracy placed them in the top one to 2% of more than 100,000 forecasters who took part in the US government research project, or on the public forecasting platform Good Judgment Open. These super forecasters are a diverse group with professionals ranging from finance to intelligence, management, to medicine, and psychology to archaeology. Most have one or more graduate degrees, and a third have doctorates. A third of super forecasters live outside the US, and most speak two or more languages. Good Judgment super forecasters analyzed 22 questions related to the long-term risk of climate change. Halfway through the project, 10 subject matter experts examined the initial forecasts and provided the super forecasters with feedback and additional sources. After which, super forecasters had the opportunity to consider and react to the expert feedback. Over the course of the project, 51 super forecasters made a total of 1,377 forecasts and 1,821 extended comments. That's kind of what the report is. And now let me give you just a little brief summary of some of their conclusions. And the way that they summarize these is in sort of probability distributions over outcomes. That's kind of hard to describe in audio. But a lot of the distributions we've heard of, the mean, mode, and median were all kind of similar to each other. So generally, what I'll just give you is sort of the most common answer that they gave as forecasters, and usually, that's going to be pretty close to the mean anyway. Okay, so one thing that they were predicting is the total tonnes of CO2 emissions per year. The estimate they gave for 2023 was about 37 billion tonnes. And the estimate for 2050 was about 35 billion tonnes. So, maybe slightly less, but about the same, basically. So, it sounds like their prediction is that the amount of CO2 emissions is gonna stay the same, which is kind of interesting. Now, of course, this is a probability distribution. So there's tails, where the emissions are a lot less, there's a lot more. But it seemed like the center of the distribution was that the emissions would be about the same in 2050 as in 2023. Another thing they predicted was about the yield from cereals per hectare. So basically, how much food are you getting out of each hectare of land? And interestingly, in the condition where they said, “Well, what would happen in 2100, if there is seven degrees more warming than there was in 1880. And even in that scenario, it seemed like they expected the yield to keep increasing. So in other words, they will be able to produce more food per hectare of land. In terms of the yield per hectare, they don't think that even with a seven degree increase in temperatures in 2100, compared to an 1880, that that will significantly reduce the amount of yield that cereals produce. Okay, another estimate they made was around the FAO food price index. It's a measure of the international prices of a basket of food commodities, because you could ask the question, “Will climate change greatly increase the cost of food?” And their estimate of this index for 2023 is around 140. Their estimate for this in 2050, it gets kind of more distributed, but it's about 80 to 150. So it seems like they think that in 2050, food prices will actually be a little bit cheaper most likely than they are in 2023. Then in terms of their estimate of about 2100, if temperatures increase greatly (so they go up by seven degrees) what will food cost? Their estimate is about 120 to 170. So something around the same as 2023 up to a bit more expensive. So up to like 170 rather than 140. I'll just do a couple more. So there's one about heat related deaths. This is one where they actually thought that heat related deaths, if they're seven degrees of temperature increased by 2100, could go up quite a lot. So in 2023, there's about 225,000 heat related deaths, whereas in the year 2100, they expect that there's about a 58% chance that it'd be over 1.2 million heat related deaths. That is kind of a substantial increase, although there's still not a huge number of deaths compared to people dying from all sorts of things. Then with flood deaths, if there were seven degrees of warming, they expected them not only to double from about 7000 to about 13,000. So really, not much increase. Storm deaths, they expected compared to 2023, they expected them to go up quite a bit from about 2,523 to about 12,500 in 20 50. So that's quite a big increase. But then that's very, very low numbers overall. And then, the last one I'll do is drought deaths. There's expected increase in drought deaths, but again, to some really low numbers. Still, it's about 10,000 drought deaths in 2100, with a seven degree increase. So anyway, I would say that the overarching result of this report is, in almost every metric, it just doesn't look that scary. And food prices are still going to be reasonable, even with a seven degree increase. Heat deaths will go up a lot, but the numbers are not massive. Deaths will go up from floods and storms. But again, these are tiny numbers. So going up quite a bit, just numbers are still tiny, and so on. So anyway, that's where we stand with the report. Now, Diana, I want to pull you into this. I don't know how much you had a chance to look at this report, but I'd love to just get your initial reaction to this.

DIANA: Oh, thank you, Spencer. But that was a lot. Not to speak very long, but there are so many, so many things that I would like to debunk or reflect on. So I'm not even sure where to start. First of all, I want to touch on the fact that I never liked forecasts because there are several problems with forecasts. Of course, forecasts with regard to natural systems, that's one thing. But forecasts with regard to societal systems that are very problematic, because the future is not something that exists in a crystal ball. The future depends on us and what we do. And when we forecast something, then people accept that that's the way it's going to be. And then people are going to go that way. So just as an example, so many of us, climate experts, were asked before we went into Paris for the COP 15, which is the big climate summit where the Paris Agreement was negotiated and agreed. And before we went to the meeting, everyone was, “Okay, what's going to happen?” Of course, all of us thought nothing was going to happen. We had so many climate talks, so many climate summits, never anything really happened. And even the little thing, the Kyoto Protocol, we agreed, but it hasn't really made any difference. So why would anything be kept in there? But if we had said that, would 140 heads of state appear in Paris? No, they would have stayed at home. But we didn't say that. We were saying very diplomatically that the future depends on us, and there's still a chance for us to solve this big problem. And as a result, 140 heads of state came to Paris. That's more heads of state ever, than any civil war, any massacre, any world war, any financial crisis, anything would have brought together. So that means already in 2015, the heads of 140 countries thought that this is a more important problem than almost anything else that has ever happened in history and came together. And we had, as a result, a really historic milestone, the Paris Agreement, which actually ran well ahead of science. At that time, any scientist would have said, “Well, actually, we really should try to treat global warming at one and a half degrees, and not two,” was kind of dismissed as a tree hugger. But the politicians then said, we have to keep global warming well under two degrees. And all of the world, including the United States has ratified this agreement with historic speed, no other global agreement has ever been ratified at that speed. So what I want to say is that the future depends on us, the future is in our hands. And we have to be very careful with what we say. So that's one thing which I want to say. The other thing is, of course, the things that you have been saying, fortunately, are not really predicting the worst thing. So in this case, it's perhaps less relevant, but still very relevant from the fact that I think all of these reports that you have cited so far were just looking at the wrong indicators. And coming back to the very first one that Misha cited, for example WHO — I looked at the source — it did not claim that climate change will only cause 250,000 deaths per year later on. It said due to diarrhea, malnutrition, and whatever from the heat will cause 250,000 deaths. But that's a very small fragment of how climate change will make people suffer. But let's take one more step back. I don't think death is the right indicator. First of all, we are all going to die anyway. So we can already predict that there will be 9 billion deaths, or whatever number of deaths in whatever period, because we are all going to die anyway. Much better indicators are really, it's a very good question, what are good indicators of human suffering? Because we could look at the economy, but the reason why there are very few quantitative projections on the economic impact and economic suffering, there are some, but the reason why there are very few is it's very difficult to predict. As long as we have to project how natural systems behave. Even that is becoming very complex. And I hope that we will get the chance in this conversation to talk about that. And I will have a chance to highlight a couple of the just really scary complexities in this whole climate change issue just as far as it comes even just for the natural systems and earth systems. But when it comes to societal systems, just tell me which of your super forecasters ever predicted the pandemic and what it will cause? Tell me which of your super forecasters ever predicted any of the big financial crises, which of them predicted the Russia-Ukraine war? None of them. These major societal collapses and societal problems can be triggered by the wing of a butterfly movement and the same is true for natural systems. But simply, the human reaction to storms, droughts, or heat is not at all from the direct impact of death. And that's exactly, I think, why Misha has not found so much quantitative data, and so much quantitative numbers on what's going to happen, because there are two problems here. One problem is that we scientists have been looking at climate change and its impact in our own little boxes, in our own little department, in our own little models. That means, yes, let me look at this. If there's a heatwave how many more people will die from heat. But in fact, the heatwave never comes just as a heatwave. And the last summer has been a superb, cool example of what it really means to have a major heatwave. What happened in Europe was okay, so there was a heatwave. It was hot. It was even a 500-year record, but it was, altogether — for example in Hungary — it was only two degrees centigrade warmer on average than an average summer, which one would think, “Two degrees? You don't even really notice two degrees. Why all this fuss about?” Okay, but what happened? Because of the heatwave, we already started with very, very dry conditions. [inaudible] So we ended up with a very severe drought. The severe drought and the heatwave together increased fire weather. This is very usual for you to hear in Canada and the US. But in Europe, except for Southern Europe, we don't have fires. We don't have bushfires. And wildfires, suddenly, half of Europe was on fire. But also we stopped being able to ship things. So even a lot of our commerce stopped because we did not have enough water in our rivers. It never happened before that the river Rhone and other big rivers were simply dry. This is not what Europe looks like. We also weren't able to run some of our power plants, because both hydropower and nuclear power require water for power production. Also, simply many municipalities just ran out of water. If you don't have water, you can be any rich, but you cannot buy water in the long term, you cannot produce, you cannot manufacture water. And even worse then, agriculture failed. And for example, in Hungary, we lost three quarters of our corn, of our maize harvest. It's still not so bad because we were exporting most of this. but because this was compounded by the war right next to us — I'm living in Hungary, and we are right next to Ukraine — and Ukraine is one of the biggest grain suppliers, because of the war, this grain supply exports have failed. But we know also that at the same time, there were also droughts in India and in Africa. And so their grain exports also were constrained. So what happened as a result, in Hungary, our food price inflation, one on one, is at 40%, just according to the official statistics. So what I'm saying is that just a slight two degree warmer summer, in the end resulted in just this, the 40% rise in food prices. And Hungary is not all that rich. So it is affecting people's quality of life very significantly. And there is a cost of living crisis in many parts of Europe. So my point, what I wanted to illustrate with this example is that, just looking at the direct deaths, an event directly — how many people are killed in a storm — is really the wrong indicator. And that's one thing. But the other thing is that, because we only looked so far at single effects from single things, that's why we have very little understanding of this compound — what we call the science — compound risks, or compound events, or cascading risks. And that's exactly where a lot of the publications came out in the last year. And we don't even spend research efforts, research money, on extreme climate scenarios. In Nature, which is one of the most influential scientific journals, exactly this year, a major commentary came out with a lot of the top climate scientists saying that simply we don't have research on extreme climate scenarios, because we are only just investigating the mean, what may happen. But unfortunately, these bad scenarios could happen. And we have no idea what will happen then, because we don't spend research money, we don't spend effort on understanding them. And we don't put the scientists from very different disciplines to think together, what happens if these multiple things happen together? Or are these risks cascade after each other?

SPENCER: That's super interesting. And I actually think a bunch of the things you said are going to frame the rest of this conversation. So I kind of want to come back to a number of the points you made. And as you follow up questions about them, and also get Misha's thoughts. But before we do that, Misha, anything you want to jump in with?

MISHA: Yeah, there's something I want to say, which is, I think, Spencer, as I've mentioned, I'm always like the meta stuff. And these conversations always matter a lot to me. And I'm not an expert on climate change at all. But I am an expert in how people talk about difficult and contentious issues. And I think one of the things for me that's really interesting about how people talk about (say) climate change is how quickly it is for people to move from a place of curiosity to a place of advocacy, like from that sort of scout mindset of wanting to know what goes on, to that sort of certain soldier mindset of wanting to advocate. And one thing that I feel like, because I feel like I've seen that happen just between us in the last 20 minutes, and I think we all contributed to that. I think when we were all hanging out at the beginning of the podcast, or before the podcast, Diana and I were talking, and I was sort of saying, “Oh, I feel really nervous to talk about this stuff. And I'm not really sure how I feel about these opinions.” And Diana, I hope it's fair to summarize. I think part of what you were saying was like, “Oh, wow, Misha I read the stuff that you read, and I feel like there's actually a lot for me to learn in there. And there's stuff where it leads me to question some things.” And we were kind of talking collaboratively about this thing. And now I feel like what's happened is we've fallen into something where it feels like a debate. I mean, the last thing Diana literally said was like, “I'm gonna have more bullets to fire.” And maybe you just made bullet points, but it feels to me like that too. I feel like what somehow we did was, Spencer you and I spent like 10 minutes giving up a whole bunch of points for one side of the argument. And then Diana, understandably, responded with like a whole bunch of points for the other side. And now, my emotional inclination is like I want to push back from my side. And I'm kind of dismayed that the conversation has gone that way. And I think that there's something in that that actually characterizes why it's hard for us to get accurate information about climate change is that I feel myself becoming less curious in digging in more. I want to point out that that's happening. I'm curious if it feels like that to you guys, too. And I also wonder if there's anything we can do to change the conversation to make it feel a little less like that.

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SPENCER: I feel like we're just beginning to dig into this. And as we go into the specific points, I think we're gonna have an interesting conversation that won't be too contentious, and we'll see each other's perspectives. But yeah, Diana, I'm curious to hear if you have a reaction to what Misha said.

DIANA: Yeah, that's very interesting, Misha, that you're saying that. And it's true that perhaps I haven't had a chance to say a few things that I said before we actually started the podcast while we were just waiting for it to start. So, it was really very useful for me to read all these materials. And it did stop me to pause a little bit and ask myself, “Are really my worries unfounded, or founded? Am I maybe overreacting?” And it came back to just the right time. It's very interesting, because I'm starting my climate change course on Monday, and I'm coming back to university lecturing after two decades of being absent from there. Of course, I lecture a lot about climate change, but I'm not actually teaching a course. And for that, I have just slipped through all the nights and so on a lot of the material, which is out there. And so, Misha's material really prompted me to stop and make sense of all of that and put it into place. But I think when you recited all your facts that you have found, and then I look back again, of what I looked again through all the nights, and in what we work within the IPCC, then Misha, I think I did get convinced, again, that unfortunately, these numbers are really not the right numbers to look at. And they are just some very, very superficial marginal indicators to the real extent of the problem. And the reason why I am actually not that happy to take the conversation away, just making climate change just as one general problem, because I do sincerely believe that it is the biggest problem facing humanity right now. I do hope we will solve it. But right now, we don't look like one. And just give you one fact, which is not a scientific fact. But I think it illustrates that those of us who really are into the science of climate change, that perhaps this is really bad, because a recent paper in Nature showed that 60% of IPCC scientists face various levels of mental health issues related to climate change. And if I remember, I think the number is also at 60%, who have already changed their life decisions significantly as a result of climate change. For example, either decisions about how many children, or to have children or not have children, or where to live. So that means that the scientists who really see what's coming are very worried. But it is true, I think it is important to acknowledge that the level of worry and the level of fear, or the level of belief of how bad it is going to be is very different among different scientists. And that's why I said I'm not representing the IPCC perspective, just my own. But then just to give you a few indicators that I would give you on the other side, which are also numbers, but that just gives you another perspective. This is just going to be a couple of facts. Carbon dioxide concentrations in the atmosphere. Just within one generation — I don't exactly know how old you guys are, but I'm sure that within all of our lives, so just within our lifetime and less than within our lifetimes — we have turned back the earth's geological clock by 2 million years; carbon dioxide concentrations have never been so high for 2 million years. Also, we could go on and on. The concentration of methane and of other greenhouse gases also have been so bad. The acidity of the ocean hasn't been so bad for 20 years and so. Also, just some other small facts that are not even talking about seven degrees, because we can talk about the seven degree future, but I just don't see how humans can survive that. But let's just talk about just three or four degrees warmer world, which can easily arrive by the 2070s. In that scenario. Also, PNES (which is the Proceedings of the US National Economic Sciences) paper says that 4.5 billion people would live in places that are just simply going to be uninhabitable, just because of heat, and not even due to sea level rise. Because currently, there are few places on the earth that simply are too hot for people to exist; too hot and humid, only hot or hot and humid. Because we just function at 36 degrees. In order to be able to survive, we constantly have to get rid of heat. So the calories that we eat, we burn them up, and we have to get rid of this. And as we know from our physics class, heat flows always from hot to cold. So we always have to get rid of this heat. And temporarily, we can — and I'm sorry, because I guess you work with fahrenheit, right? So whatever Fahrenheit. — but if it was temporarily hotter than that, you can temporarily handle that by sweating. But if it's too humid, beyond a certain point, you cannot even sweat anymore. So simply, after a certain while, your organs start to fail, because you cannot get rid of the heat that is inside you, and simply some of your organs will stop being able to function anymore. So there are simply physical limits to the existence of a Homo sapiens. And right now on earth, there are few places where this exists, but very few (in the Sahara, and some other tropical places). But by 2070, we expect that unless we do something seriously different, then this is going to be a very significant part of the world, which is going to experience such condition. So it's not that they're going to die. The question is, if 4.5 million people start to find another home for themselves, do you really think, Misha and Spencer, that currently nation states will be able to handle that? That pressure that 4.5 billion people will need to find another home for themselves. And that's just one single problem — heat — and we didn't even talk about food production and [inaudible].

SPENCER: I think it might be useful at this point to dig into this idea of weather forecasting, like this Good Judgment Project is a good way to look at this. Because you're saying that at three or four degrees C increase, 4.5 billion people may live in uninhabitable regions. But to me, it seems very hard to square that with the Good Judgment estimates. Do you disagree with that? Or do you think that that actually can be squared with the Good Judgment estimates?

DIANA: Oh, no, no, no. That's why I'm very skeptical about such forecasts, because the problem is that the vast majority of such forecasts work with extrapolation of previous trends, and looking at what happened in the past and trying to see how we might learn from that, and how that will pan out for the future. But what my point is that climate change is so disruptive, and it puts us into situations which we have never experienced before. And this is not about incremental change. But this is a fundamental disruption of our lives and of civilization, and on the fundamentals of civilization. If we think about that, I think another really important fact for these forecasts also, that if you look at the geological history of the planet in terms of temperature, yes, the earth had been colder and hotter. But interestingly, [inaudible] have roamed the planet for 3 million years. Also, Homo sapiens has been around for hundreds of thousands of years. Yet, only since when do we have civilization? We only have civilization and the Earth itself has a four and a half billion years history. We only have civilization since the climate entered a very stable era. For the last 10,000 years since we count civilization, the temperature of the globe has not moved out over one centigrade (I guess it's about two Fahrenheit if I'm right). It has never been hotter or colder. So civilization has been very finely tuned to a very stable climate. Where people live, what people eat, where they produce what they eat, where our country boundaries, even political systems, everything where wealth is, how we make our wealth, what we drink, what we like, what we do for leisure and what we work, all of this is really strongly defined by this extremely stable climate, which has been stable for 10,000 years. Already now we have moved out by one degree centigrade out of this very stable era. We are playing a huge global planetary experiment and societal experiment. And we see, and I do believe, that also the pandemic and the war and all these crises are partially the result of exactly our ecological pressures. And there's no way your super forecasters can ever have all of this wisdom in their forecast.

MISHA: I want to name what I think is a point of agreement that I just want to summarize. And then, Diana, I want to ask you a question or two. There's one point of agreement that I think is just worth saying, but I think should be evident. I think that all of us here agree that climate change is a really big deal, that it's complicated, that we probably need to be doing more to address it. I don't think anyone's disagreeing with that. The other thing I think that's a really important epistemic thing that I think Diana, you're talking about, and that I agree with — and I think, Spencer, you agree with too based on our conversations — is that whatever it is the forecasters say, this is an incredibly complicated issue. And it's certainly not an issue where any of us imagines that any group of experts can predict with tremendous certainty what's going to happen, because, Diana, for all the reasons that you say. It's an incredibly complicated interaction of physical systems, but more importantly, an interaction of social systems. So, whatever the forecasters say, we also understand that it could be very different. And I'm 100% in agreement with you on that, Diana. I think that, yeah, whatever they say, we don't know. There's a huge amount of uncertainty. And Spencer — I'm going to refer to conversations that happen outside — Spencer, I know that when you and I have talked, you're always (I think) concerned about those longtail possibilities, because, yeah, we don't know. And, and the things that seem like that might happen that we don't know about seems pretty terrible. I think we're all in agreement on that. Does that sound about right?

SPENCER: I think that sounds exactly right. And I think part of this debate is around, what is the sort of central estimate the mean estimate versus what is the tail risk estimate?

MISHA: A related question, I suppose, that I want to ask Diana is, if I'm a lay citizen who believes — as I do — that it's really hard to know what's going to happen with climate change. At the same time, as with things that are unpredictable, I still think it's possible to sort of get a sense of what I should think of as the most likely outcome, what I should think of is the range of distributions of outcomes. Even amid uncertainty, at some level, we have to quantify our uncertainty. But even within uncertainty, we want to quantify our risks, even if what we're doing is quantifying that uncertainty. And so the question for me is like, as a lay person who's trying to get a sense of how bad is this problem likely to be, in ways that are quantitative, in ways that quantify the impact and the risk? And I'll put those in qualitative terms. As a layperson, is it likely this is the kind of thing where civilizations are going to collapse? Is it likely where this is the kind of thing where everybody in the world is going to be starving? Or is it much smaller than that? What sources should I be looking at for me to get a quantitative sense of what the risks are, how big it's going to be, and how likely it'll be? Where should I look to find that out?

DIANA: Yeah, I think, Misha, I fully agree with you on many of the things that you just said. I don't quite agree on the fact that we're talking about tail risk, since the fact that I quoted from the PNES paper on the 4.5 billion people, I think that's not a tail risk. It's simply, if we get to three to four degrees, it's almost guaranteed that that's going to happen. And as a matter of fact, it's very interesting that just today, and when you talk about we just can't know what the future is. Well, actually, we can know a lot of this. Simply, the problem is that in the past, a lot of this knowledge has been obscured by interest. Just today, a very interesting paper came out in Science, which is definitely the most influential scientific journal that exists by two of the climate change super powers [inaudible] And what they are showing is that — and I don't know whether you allow the company names here, maybe I won't say that — but that paper is actually really about one particular oil company, how that already they had in the 70s more exact forecasts on climate change than NASA. Then, most of the predictions or projections on climate change were not as accurate as compared to what already we see has happened as their forecasts, so they knew all the way along. They knew everything in there, their scientists have projected. But in their public communication, in all their lobbying, was total denial and a very different communication. So one of the reasons why you are not able to find so much, or a lot of things are confusing, because exactly the interest, that whose interest it is to keep the status quo, to keep this kind of economy that still relies on fossil fuels, with enormous amount of money, is very effectively obscuring a lot of this knowledge to be publicly available and to be out there. For example, right now,with the war and with the terrible energy price hikes and energy market shocks, they are making amazing windfall profits, while billions are freezing. Or, at least in Europe, hundreds of millions are cold. Fortunately, our weather has been much warmer than the normal winters. That's the only thing that saves us from a lot of cold related deaths and generally just suffering. But the point is that with this enormous amount of windfall profit, a lot of that they're still using to exactly make sure that people like you don't get the kind of information that we have and we know.

MISHA: So to unpack that question again. So what sources, if I'm, as a layperson, trying to get a quantitative sense of the risks, including the uncertainty, where should I look? And I'm not asking that rhetorically. I've spent days and days and days trying to find the answer to that question. And it's been very confusing, so I'm curious. And so for me, the best answer that I came up with was the super forecasters and prediction markets. And you're telling me not to look at those. So where should I look?

DIANA: Definitely where you should look is the IPCC, the Intergovernmental Panel on Climate Change.

MISHA: When I looked through the IPCC, and I looked for quantitative measures, the most, and I found it super hard to read, I brought in a bunch of smart, quantitative-minded friends to read it with me. And the worst quantitative measures that we could find — and my understanding is these weren't single cause, this was the attempt at a multidisciplinary measure of total excess deaths from climate change, from all causes, I think (and I might be Miss reading it). — But even then, in bad situations, — and I now understand excess deaths aren't the only measure, but they're one measure — that even then, what I saw was net excess deaths that were (again) comparable to things like obesity and smoking. Maybe I'm misreading the report. But if that's the case, then it really looks to me that either there's something really missing and certainly the clarity is rough. But maybe there's something missing in the report that's not being captured. And if so, where should I be looking to find that if it's not in the report?

DIANA: Because simply, the kind of numbers you're looking for, first of all, may not fully exist. A lot of them are in the IPCC report. So a lot of the facts, the time I'm quoting to you now, are from IPCC reports. But what happens from them in terms of societal pressures is not in the IPCC report. The real deaths will come from wars. Can we predict the number of wars? We cannot predict the number of wars. The IPCC also says that climate change is not alone responsible for war, but it's making other societal problems worse. And that's exactly what I illustrated with the war and how it made, for example, our food prices increased so much. And these kinds of risks, we cannot attribute solely to climate change, so this is not in the report. Also, we just said that the recent papers are just coming out that compound risks. We haven't done enough science on this. There is not enough research on this. So my point is that you will not be able to find a lot of these very quantitative, worst case scenario forecasts for long term because simply there's no funding for this. Nobody pays for any research group to quantify this. Because nobody cares what happens in 2100. Governments are interested in what happens in a maximum of 20 years or 10 years, and what can I do tomorrow? And what is going to happen while I'm in government. So nobody is funding this. What I want to argue, Misha, is that the better way to think about this is not looking at very quantitative risk. Think about if your child — I don't know if you have children or not, but I'm a mother — so if your child is diagnosed with cancer, would you sit down and spend most of your time about “Okay, well, how serious is it? What's the quantitative risk, and what is exactly the chance of...?” No. What you would do is to do your best and put all your resources into making sure that even if there is only a 2% chance to save the child, that it goes that way. Also, there's an 80% chance to make sure that we really get into the 80%. So what I'm arguing is that we are gambling with a huge system, the planet (but not the planet), with civilization. And the reason why it's not a good idea to gamble, whatever risks come out, whatever quantitative numbers come out. It's just very uncertain because it has never happened before. We are heading into what we are already has never happened before. And the reason why this is not really worthwhile spending all our energy quantifying the risk, but instead, it's much better to spend all our energy looking at the alternatives. And please let me finish because I think these are really important points. Because we know we have the solutions, we know that the solutions can be implemented in ways that don't disrupt societies. But in fact, if we make the right choices, we will have a much more 21st century compatible society, economy, much more health, we know we are going to live better, we will have a better quality of life, we will have less injustice. In general, the world will be much better off. So why quantify, why go on and on about quantifying risks and so on? — I have this fantastic meme in which these dinosaurs are standing, and there is this comet coming already in the sky. And they are looking at the science and drawing the lines and saying, “Let's exactly calculate the cost of us developing the technology or just implementing our technology to get rid of this comet.” So the point is that simply sometimes the numbers don't matter, because simply the alternative is so much better anyway. But the reason we are not going into the alternative, because right now the incumbent power system's interest is to keep the present economic systems which are already these economic systems of the past, where it is energy systems of the past, and we are just not able to move. So anyway, I know I'm throwing in a lot of new stuff. But that's my meta topic where I think this whole discussion is leading us into that we know enough. Yes, you're right, we may not have quantified everything so well there. But it's more than enough what we know already, that the risks are high enough for us to really put everything into saving our child. And we know we can save the child. And we know we will even be better if we go make that (let's say) dietary changes or whatever. We just have to somehow try to think about how to resist the present power structures.

MISHA: And for sure. I agree. And again, I agree that part of what makes it so hard is because there are so many interests at work, and corporate interests, among them, making it really hard to get clear pictures on this stuff. I think that that's true. I also think yeah, you don't want to over quantify things. But maybe I do disagree with you a little bit about saying we don't want to quantify it, because to me we do. Like one of the things that you say is you say, “I'm certain that this is the biggest problem facing humanity.” And I feel that when you say that, you've basically quantified the risk. What you're saying is, “I don't know what the number is, but it's bigger than the other numbers.” So you have. And so when I say quantifying, I'm not saying it down to the decimal. I'm saying to within an order of magnitude or two or whatever. And, so part of what I'm hearing from you is what you're saying to me is like, “Misha, the quantitative risk that you, Misha, are perceiving from looking at the data that you've been able to find is somewhat very, very, very different from the quantitative risk that I, Diana, am saying is at work. Because, again, just with orders of magnitude, all the numbers that I find — and I want to say from any sources at all — seem to suggest that the more likely outcomes — and again, I recognize that there's a huge amount of uncertainty. And just to be clear, I think climate change is important, I think we should be doing more about it. I think the fact that we're not as tragic, I think that the fact that we're not is because, in part, of corporate interests, like things you name. I agree with you on all that. And at the same time, maybe I think a little differently than you do about quantifying risks, which is that, if I was told that my kid had a serious disease, I would want to know what the risks were, I would want to know what the chances were. So that, for instance, if I could choose between two very difficult treatments, I'd want to know which was the more likely one to work. Or if my kid had something that was scary sounding, I also might want to know if my kid only had a 3% chance of dying. I might want to know that as opposed to my kid having a 70% chance of dying, because it might alleviate my anxiety. A 3% chance of dying is scary, but it might help alleviate anxiety to know that the kid also had a 97% chance of survival. So for me, attempting to quantify those things, even on those big issues, feels important. And for me, I guess, I'm maybe a specialist comes back to some of the stuff I feel like you want to talk about, which is like how the forecasters work and stuff. My understanding of the best sources that I know of to look at for that is the super forecasters. I know, Diana, you've said that they don't consider all these different things, and they just extrapolate. But my sense is that that's not what they do. My sense is that the winning super forecasters teams try to do all the very things that you name, and they try to do it in ways that are of course imperfect. And like you said, you can't predict wars, you can't predict those things. But what you can do is you can begin to assign ranges of possibilities. Maybe you think it's impossible to do that. But I guess the thing that I think is that you're tacitly doing it. If you say there's going to be wars, what you're doing is you're tacitly saying wars are likely. If what you're saying is you know migrations gonna produce political instability, what you're doing is you're tacitly making assumptions. And then, what I think the super forecasters do is they try to bring their expertise. And I think they bring in expertise that we don't have, like I respect experts. I respect the scientists to predict the models and stuff like that. And then I also respect the groups of political scientists who, with good track records of predicting political science things, which are hard to predict for sure. They're hard to predict in business, but people don't have good records. I don't know, like, will climate change result in war? I don't know. Who do I ask? And one person I could ask would be climate scientists, or another person I could ask would be a group of political scientists who have a proven track record of being good at predicting political events. I'm going to trust the second group better. They're the experts with a proven track record on that.

SPENCER: I really want to dig into sort of what I think the crux of the disagreement is here. Because I actually think we agree on a huge amount of stuff. I think we all agree climate change is a really big problem. We all agree that it could go incredibly badly for humanity, right? We all agree that it's way under invested in, in the sense that there's not nearly enough being done. And so, what are we actually disagreeing about here?

MISHA: I think we disagree about a couple things. I think we disagree that if we were to draw our own subjective distribution curves of the risk, I think they would look different. So I have a feeling that if Diana were to build her subjective distribution curve with the risk — and you can tell me if this is right — then it sounds like the most likely outcome, or at least there are some pretty likely outcomes that are very, very terrible. Where I think, Spencer, what you and I think is that the most likely outcome is one that's pretty bad but not terrible. And we're scared more about the stuff sort of further out on the graph. I think that's one thing where I disagree. I also think we disagree on what sources we think are trustworthy. So I think, Spencer, you and I tend to really believe a lot in super forecasters and prediction markets. And those are the sources from which we draw those beliefs. And Diana, I think, in part because you have subject matter expertise, you're like, “No, I just trust my own expertise over those things.” Does that feel like that captures that?

DIANA: My problem is not that they don't look at the tail risk, but I think some of their numbers must be totally wrong. For example, claiming that under a seven degree world, [laughs] grains may be even higher. I'm sorry, but this actually really makes me laugh. I mean, maybe. But there won't be humans who can harvest or who can put that grain in the ground. In a seven degree warmer world, we just won't survive. Perhaps a few people may. But some of the super rich, who somehow managed to right now incubate themselves and somehow make sure that they can exist in some artificial environments. But it's just very hard for me to imagine. In a seven-degree-warmer world, definitely the vast majority of the population will not be able to survive.

MISHA: The question I want to ask, and this might seem like an aggressive question, I guess it is, but it's really an important question for me. My big question is, how am I as a layperson supposed to understand this situation? And one of the things for me is that as a layperson, one of the things I'm often inclined to do, that I think is a good thing to do, is sort of trust expertise as a kind of black box. So what I want to do is I want to find the best experts to listen to, and then believe what they tell me and not have to worry too much about the arguments that they make, because they're the experts. Because if I start listening to arguments, I kind of feel like I'm like “doing my own research,” and I'm like, “That's not my job.” So I'm really looking at a black box. So I have a choice between two sources to believe. So here's this thing from super forecasters that says that under seven degrees, we're gonna see these things. And the super forecasters — Spencer sort of described how that works — it's teams of multidisciplinary...

DIANA: Can I finally state my arguments why I think they are totally wrong? So I already said that our physical being has physical limits for existence. That means that at seven degrees, the vast majority of the planet will just not be habitable, except for air conditioned spaces. But for half a century, we have not been able to provide clean drinking water to billions of people. And just the pandemic pushed another billion people back to extreme poverty. How do we expect that just in a few decades, we are able to provide air conditioned spaces for everyone? And it's not for living, but it's about agriculture. It's about work. We simply will not be able to do work outside in these places. How could we have agriculture? But also, they have smartly, I think probably those who asked the questions already were manipulating this a bit, because it's about yield. Yield is about per square meter or per unit land, but not about total yield. Because if you look at it, if you look at the global map of where is produce today, this is actually a very narrow band on the whole planet where we can really produce a lot of the world's bushes, basically the breadbasket of the world. And even with one degree climate change, these ranges have already shifted a lot. With seven degrees climate change, I don't know where these ranges shift. I have not seen the map with that. I don't know if they looked at it, maybe Siberia still may have, and maybe some of Canada. But I simply don't know. But then, do we really believe that all of humanity can go and live in only these very little places? So simply, it's a laugh that we are asking questions which presume that everything else is going to go exactly how we live today. And we are just looking at exactly the yields, and looking at just the CO2. Actually they do show what the factors are. They don't look at the shift in the climate exhaust, but they do look at CO2 fertilization, precision agriculture. But for example, I just happened to talk to my son before we started this, and I just told him exactly this fact about this yield because I bursted out laughing when I read this forecast. He asked me what I'm laughing at. And I said, “Okay, what do you think?” He has just come back from one of the biggest global companies. He didn't want me to say the name but it's a pharmaceutical company but mainly they produce agricultural chemicals. And there, it's really seen in the research to find exactly the chemicals for precision agriculture. He also laughed, and not because he doesn't understand my clarity, but he understands about agro chemicals and food production. He said that we already have our really big problems with this huge monoculture agriculture. And already finding the next chemical, we are constantly running away from the fire and the fire is always behind us. And we are just happy to develop the next molecule, to which the pests are not resistant. So even without climate change, we have huge problems with our monoculture agricultural practices. And with thousands of percent of growth that we expect by business as usual, simply, it's just a completely different planet that we are talking about, and there is no way that we are going to keep these high yields. Also simply because the storms are going to be destroying them and the soils are going to be so much damaged. So altogether, maybe they are very smart guys. But because they don't see all these complexities, and because out there — as you correctly said, Misha — there are not a lot of facts and risks out there, which really captured the compound risks and these cascading effects. And this is why I think they were not able to put into their forecasts a lot of this knowledge that we just know implicitly.

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MISHA: One thing that I want to say is we've talked a little bit about the materials that, Diana, I shared with you and Spencer. I'm happy that this was like a slide deck that I gave at a really small conference of a couple of dozen people. But if you think it might be of interest to your listeners, I haven't shared this publicly, but I'd be happy to share it if you think that that might be interesting. We'll put in the show notes. Because I think that might be helpful in terms of getting at some of it. This is just like one small thing, but it really feels to me one of the things I'm always interested in is the way in which the same data can be interpreted in different ways, depending on what your viewpoint is. And one point that came up for that was like, Diana, earlier, you sort of said that, like, it's an indication of how serious this problem is that something like 60% of people who are working in the field have depression and anxiety. And so there's this data point, which is that 60% of the people in the field have depression anxiety. And one way to interpret that data point, which I think is a legitimate one, is to say that's an indication of how serious the problem is. Another way to interpret that data point, if what you're worried about is like, “Oh, the field is in some ways overly pessimistic.” It's like, well, if the field is populated 60% by people with depression and anxiety, one thing about people with depression anxiety is they tend to interpret things in ways that are overly pessimistic. So even that one data point could kind of go either way, and I kind of left off the page a little bit for me, because I think that that's one version of the story is like, “Oh, this field attracts people who are people who think that this is a huge problem and people who worry about it a lot. And so, even when they're looking at data that says that things are only pretty bad, they're gonna look at the data that says that it's horribly bad.” I don't mean to argue against all the points that you make, which I think are really important points. But it's just one example that I kind of stuck out from.

DIANA: Can I just react to that? Because I think that's a very, very interesting point. That's a very interesting point. And then a very important question to ask. But, why I don't think that's true is because those people who already make it to IPCC, you really have to be extremely motivated, and extremely energetic and extremely committed to something because all what we're doing at IPCC is voluntary work. So we all do this above our regular job, and often at a large expense of family. So these crowds are actually no means the kind of depressed scientists who just do their job. But they are the people who are extremely energetic and active, very fun people, we have so much fun. Of course, this is by no means proof. And even this data point of the 60% percent, it was just one piece of data for you guys to think about. But certainly, it's not proof or anything. The proof is more about some of the data points that I already have. And just one more fact to add to the seven degree thing. I just looked at the data. You know when it was last so hot on Earth with some degrees hotter? Fifty million years ago. Fifty million years ago, the Earth was completely different. Why do we think that we'll deal, or we'd be even better when 50 million years ago, they were completely different species. Just from a few degrees centigrade of climate change, sometimes more than 50% of all species disappeared from the planet. Why do we pretend that our food stock is going to be exactly the same in a seven degree warmer world? So that's just to me, so, so, so funny.

MISHA: And I think this is maybe coming to like one of the biggest sources of disagreement is like, who we find trustworthy and — I think one of the big ones is the question of like — how trustworthy are those super forecasters in similar groups? And so for me, I guess from where I sit, when you sort of say, “Oh, they miss out on the complexities (and things like that) the situation.” I guess I'm inclined not to believe that. I'm inclined to believe that if I'm a layperson, and I'm like, okay, I'm hearing contradictory things and one about what it's going to be like — and I'm trying to evaluate sources of information — and one source of information is a very, very smart IPCC scientist. And the other source of information is a cluster of super forecasters who won a super forecasting competition. And if you ask me, who do I think is more likely to be able to capture all the complexities? My inclination, as a layperson, is to believe the group of super forecasters because I believe that what super forecasters are is there's people who bring a large amount of academic expertise and other expertise, and have a proven track record of being able to capture the multiple complexities around complex questions that involve issues of science and technology and social interaction and social systems, all those kinds of things. That's what they're experts in.

SPENCER: I just want to add something to that, which is that, I guess the way I think about super forecasters is not that they themselves have expertise in any of the specific topic areas. But their expertise is synthesizing information from many sources to come up with a probabilistic estimate. And in this particular report, after they made their initial estimates, 10 subject matter experts then examined their forecasts, and then gave them feedback and additional sources. And then the super forecasters then updated their views based on that feedback from subject matter experts. So I just want to point that out. And I'm glad you're highlighting this Misha, because I think I share your intuition that the super forecasters are probably the source I trust most on synthesizing a complex topic into quantitative estimates.

MISHA: And I guess in terms of seeing the complexities, I think that there's complexities. And again, I think we all understand there's lots of uncertainty. But I think that, Diana, you named a lot of forces that are reasons to expect things to be bad, but then they name a lot of the forces reasons to expect things to be good. They sort of name all the ways in which adaptation might happen, and all the reasons to suspect things. And all those things taken together are incredibly complicated and produce vastly different answers. And again, who do I trust to take all of those complexities and be able to look at them? Well, it's a team of multidisciplinary experts who have a proven track record of doing this, who then bring in an extra 10 subject matter experts to further refine their opinions as they've done in the past. So I am inclined to think them. And then, I suppose in terms of the questions whether it matters to quantify it, I think, to me, it does because I'm going to feel and act differently. Like if there's one world which is sort of the world that Spencer's friends feel where it's like the most likely outcome is that in 30 years, your middle-class American kid is going to be living in a hellscape. That's one view of things. It's a bit of a caricature, but I think there's people who think that. Then there's another view of the world, which is the one that I see when I look at stuff, which is, it looks like the most likely outcome is in 80 years from now, things will be, for most people, a little better off than they are right now. But there are some really real risks that terrible things might happen. There are genuinely real risks, and all these things are bad. So we should still take lots of action. But to me, those are really different pictures of the world. And to me, they would involve slightly different courses of action and slightly different, even slightly different ways of feeling. For example, if you think the world's really most likely to be a hellscape in 30 years, then maybe you really don't want to have kids. If what you think is things aren't going to be as much better as they were in 30 years, and we face some really real risks of things going badly. Well, then I don't think that would affect your reason to have kids.

SPENCER: One of the things that's most interesting to me here is that when Diana looks at the super forecaster report, I think her response is that it is ridiculous. It's not even close to correct, that there's no way it could even be in the ballpark. So, I think that I just want to highlight that, as I think that's a fascinating disagreement here. But Diana, please, let me hear your reaction.

**DIANA:**I'm not discrediting their scientific qualities. What I want to know is, do they really have paleoclimatologists reviewing their forecasts, especially when we talk about seven degree climate change? I don't think there's any paleoclimatologist, who will claim that with seven degrees warming where civilization will survive as we are now, and we will be eating the same thing. Again, maybe some parts of civilization will continue to exist. But, it's certainly not going to worry about the exact same type of wheat yields, because simply, we will have a much smaller number of people living in much different places than where we live today, eating completely different things, and so on. So just the world will look completely different. And I think it's up to you, Misha. I think I had a lot of scientific arguments why these numbers are wrong and where they are. But my main argument for this is the wrong indicators. What they looked at was how many people will directly die from storms. But it doesn't matter, because the big impact will not be the direct death from storms, but the storm actually destroying your homes. Just, again, a small little fact. We have already baked in three meters of sea level rise. And with just a small increase, we can go up to 20, 30 meters of sea level rise. The vast majority of cities of the world, the wealth of the world, the cultural heritage of the world is along shorelines. We just already committed — or very soon, with seven degrees for sure — we will have committed most of this because I just looked at my data. With seven degree warming, we will trigger basically all of the Earth system tipping points that we know about. The Gulf Stream will stop or collapse. The Greenland ice sheet will melt. In Antartica, most of the ice sheet will melt. The boreal forests will die off. Amazon is going to die off, and it just can go on and on. It's just going to result in a completely different planet. So when we talk about wheat yields, again... Anyway, my point is that I fully agree with you that it will be really good actually to have all of these in scientifically underpinned and quantified studies. And I fully agree with you and I just wish governments funded such reports.

MISHA: I think we all agree that it's really too bad that there's not better data.

DIANA: Exactly. There was a paper on this calling for this. Maybe we could publicize this more in social media, and perhaps that could trigger governments actually funding such. But governments are really afraid, because that would mean they would have to fundamentally disrupt to change some of the things we do, and no government wants to do that. So difficult. But the other thing is, again, what I'm talking about is not what will happen. What I'm talking about is what could happen. But I truly believe, and this is why I think a lot of us are afraid but not depressed. Because for example, I'm actually quite prone to depression. But I'm very optimistic because I work with the solutions. And I see that there are so many great solutions, which are really going to make — if we finally get to implementing them, some of them than we already do. But some of them we totally don't. — If we implement them, it will make everyone so much better. And it's not an accident. I do have some kids because I do think we can have a much better world. So this doesn't have to happen. Yes, we have already baked in a degree and a half climate change and global warming, but I really hope that we can stop it there. And then all the bad things we have talked about will not come true.

SPENCER: I have two questions for you, Diana, that I'm really interested to get your thoughts on. The first one is, so I think a major point that you're making is that it's hard to quantify the bad outcomes because they involve multiple systems, they involve societal systems and the way people react. They involve things like climate change triggering other effects like war. And I think that those are all really good points. And I agree about the difficulty of quantification there. But I'm curious, from the numbers in the IPCC reports, what do you see as kind of the scariest things that we've already quantified, where we actually have some estimates about them? And do they look really dire or scary?

DIANA: Well, that's a good question. I think I will have to look more in the Working Group 2 report, because to me, already, these numbers are very scary that we have already turned back the geological clock by 2 million years, and just saying that our climate has been so stable for 10,000. And let me just quickly look at my numbers on the sea level rise, which we baked in. Those were pretty scary for me.

SPENCER: But just just for regard to those things like the geological clock and sea level rise. I think that those things, it's hard as a layperson to be scared by them, just because it's hard to know what they mean in terms of outcomes, right? I could see why they're scary because like, oh, wow, we're really messing with things. But what does that mean, in terms of human life? What does that mean in terms of people suffering? And so, I'm wondering, are there numbers in the reports that actually make predictions about negative outcomes for humans or for civilization, as opposed to sort of these more indirect measures like sea level rise, which is hard to know how that translates, right?

DIANA: Yes, Spencer. These are very good questions. But the reason why I think we simply don't have the right metrics, because we usually don't measure the quality of life, right? So just the mere fact that, as I mentioned, sea level rises, for example, is worrying. For example, now, with one degree of climate change, we have already baked in probably between five and 10 meters of sea level rise. So it won't happen fast. But just this summer, I was very fortunate to be able to visit Ephesus, which is one of the ancient Greek and Roman cities. That civilization has thrived for hundreds of years. And 3,000 years later, we still have that. And it's so wonderful. And we think that even 2100 is so far away, who cares what's going to be in 100 years? But think about that. Our civilization has been just amazing for thousands of years. But with two degrees of climate change, we already have 15 meters of sea level rise. With three degrees, it's 25 meters of sea level rise. That means that for Florida, for New York City, for Venice, for just a lot of the beauty and the great things that we love, we enjoy, and we have, is going to be over. So that is the wrong thing to measure things in because our quality of life is based on very different things. So for example, we know that we could make a huge difference, not only to climate change, but even to our health, just switching from eating less red meat and eating just more white meat, more poultry, or perhaps even more just plant based foods. But we are not even able to make this sacrifice. Now just think about that. Already with this climate change, we may already be losing coffee. Now how many of our listeners love coffee? Can you imagine your world without coffee? It's not death, you're not going to die. But your quality of life may suffer because you're so much used to it. If you're not even able to make this very little change, or move from one type of meat to another meat, why do we think it's not going to be a terrible world if we cannot live where we'd like living, if most of our assets, most of our wealth is going to be underwater, if we have tremendous pressures from migration and pandemics? Did you enjoy the pandemic? Yes, some of us may have, but a lot of us had suffered terribly under the pandemic, not because of the pandemic, but because of being locked in. Now, this pandemic was just a warning of what is going to come. Already every year, four new epidemics are starting in the world, and this is accelerating. With more climate change, with more loss of biodiversity, this is going to be more and more. And with more globalization, it's more and more likely that any of these new epidemics will become, again, another pandemic. And we may not get so lucky as with COVID. With COVID, we were very lucky that in the end, the fatality rate was not very high, and we managed to develop a vaccine very soon. But still, it was very significant damage on people's lives. If you look at just the death figures — okay, 3 million or 5 million whatever — they are negligible as compared to the amount of mental health issues that we are still carrying from the lock downs and so on. So what I'm saying is that simply these metrics of death and even perhaps economic losses are not the right metrics to look at how our lives are going to be significantly worse than what we have today.

SPENCER: I just want to try to summarize something that I think is kind of key here really quickly, which is that Misha investigates this topic to try to understand how bad is climate change, really. And he tries to look at quantifications. And he comes away thinking, “Wow, this qualification is not nearly as bad as I thought.” And Diana, then you look at this, and you say, “Well, but the problem is, first of all, they're not quantifying the right things. Like, the actual things that we care about are things like human suffering, and nobody's quantifying that. It's not just the number of heat deaths. That's the wrong thing to quantify. And second of all, (I think you say) plus, there's way underfunding of this quantification. We need to do a lot more of it. It would be better if we did a lot more of it.” So, I think your answer to this question is that things are going to be way worse than the reports suggest, because the really bad things are actually not quantified. And, they're really hard to quantify, or we haven't invested in it enough, etc. Is that accurate, Diana? Do you think that's a fair characterization?

DIANA: Absolutely. And I think one more point is perhaps the distribution. Because maybe on the total, you're not going to have a lot of impact. But just let me give you another example from the United States. The Central Valley provides half of the food for the United States, and also a very significant food producer for the rest of the world. For example, 70% of almond productions are from the Central Valley and so on. But most of Central Valley's agriculture comes from meltwater from the Sierra Nevada. And that relies on the fact that there is snow in the winter, there is a snowpack in the winter, which is going to melt slowly over the year. Now one of the most affected by climate change, and one of the first things that we could really find if it can be attributed to climate change is the reduction of the snowpack in the Sierra Nevada. And in general, first of all, there is less and less precipitation there. And also what's coming there is more and more going to be in the form of rain, which is going to go away when you would actually need it. So without water, what is going to happen to all the farmers in the Central Valley? I'm sure somewhere, it's possible to produce again, but don't tell me it won't be human suffering that a lot of the economy which has been around for hundreds of years, and on which people made very happy and good lives will just be lost, because already very soon, you just won't be able to do this anymore where you're doing. The point that maybe overall on curves, the middle of the curve can survive, but it will never show you this enormous distribution impact that will mean a lot of suffering. An example of that right now, all the suffering which is happening in Africa due to this extreme drought.

MISHA: I guess, for me, when we talk about those unequal distributions and the impact of this stuff on the poor, I guess there's a couple of things. (I'm just jumping on individual things here, I suppose.) I still feel like the main thing is I'm still struggling with what are the sources I trust. Because part of it is, Diana, you're telling me all these things that things are worse than they seem than what I will see if I go look at what's actually out there. And that feels confusing to me as a citizen in terms of what I'm supposed to do. Because I went out, I looked at the sources that were out there. It's not like the super forecasters disagreed with what I was seeing in the IPCC reports or anywhere else. Everywhere I went and looked and looked really hard, anything that quantified it by any measures that I could find made it seem — like I said earlier — a pretty big problem, but not the biggest problem we've ever faced. That's what I saw. And so I'm still left confused as to what I'm supposed to do about that as a citizen, who doesn't have the great privilege of being a 90-minute conversation with an expert on a podcast, which is what most citizens are like. Also, there's a couple of things that I wanted to think about in terms of, I guess, I still feel like it's important to find some way to quantify the impact. I agree, deaths aren't the best impact. In many cases, I just looked at deaths because death seemed like a good proxy. For instance, if what people are saying is this is going to be a civilization threatening thing that's going to destroy the whole world, but the total excess deaths is going to be less than we currently have from obesity. Those statements seem to me to be incompatible, that it's hard for me to imagine something that gets a civilization-destroying thing that also has excess deaths that are so small. So for me, it's a proxy for all the other things that of course, of course matter. The other thing, too, is when you talk about inequality. I guess one of the reasons why it feels concerning to me is that if the numbers are sort of the numbers that I see — I know you're telling me they're not — but so the question of whether my numbers are right or not feel important to me. The numbers I'm seeing are right feels important. One reason it feels important to me is because, like one comparison that I did in the numbers I looked at was like, what are excess deaths from climate change versus what are current deaths from famine. And when I see those comparisons, the numbers that I saw (which you might think are totally wrong), but the numbers that I saw were that excess deaths from climate change in 80 years from now are lower than excess deaths from famine today. But when I think about what I encounter in my social media, in my news media, there's so much more attention given to climate change than there is to famine. And so, to me, the question of like, so when you sort of say, “Your child is sick, what are you going to do?” But you've got 10 children who are sick, and you have to decide who you're gonna attend to first, you might care about that. And so for me, the fact that climate change, at least in my mediascape — it might not be true for you — gets so much more attention than famine, to me feels like whether that's appropriate has a lot to do with how big the problem is. And if the problems are the scale that it looks like, then that's an issue. And the one thing I'll say — and I'm doing the bullet point thing that I'm doing — is on the, we talked a bit about mental health, and one of the things that I've seen a lot is articles that sort of talk about people who are experiencing terrible anxiety and terrible depression today, because they believe that climate change is a catastrophic thing where in 10 years from now, their lives are going to be terrible, the lives of their children are going to be terrible. And what these articles very rarely talk about is whether those fears are realistic. And to me, the question of whether those fears are realistic is really important, that typically, part of how we treat anxiety is to say, “Well, maybe it won't be that bad.” And if what you're worried about is that your children aren't going to have enough food because of climate change, and you're a middle-class American person, the question of whether that's something that's 80% likely to happen or 3% likely to happen might deeply affect how anxious and depressed you feel. And a perception or belief that I have is that lots of people are experiencing depression and anxiety that might, in part, be alleviated if the numbers are different than how they seem. Is it even too late, too, to say to those people, “Hey, you know what? There are some credible seeming sources that suggest that maybe there's a better even chance your kids might be okay.” That might alleviate a lot of suffering in the world right now. So I guess thinking about, on the one hand, the present suffering from the poorest people in the world, and things like famine, or the present's suffering in the fairly privileged circles in which I travel from things like depression and anxiety. And all those things are some of the reasons why I care about quantifying this stuff.

DIANA: I think you're very right in many of these. And I wish we could actually have a conversation involving a Working Group 2 scientist, who is perhaps more moderate, or more conservative, and perhaps that would be a really interesting conversation. Because, yes, that's true. That's still in the Working Group 2 report of the IPCC, a lot of the numbers are not so drastic, and not so worrying. And I also want to hear their reactions to my concerns. But to me, the bottom line is still, first of all, I'm surprised that I think I debunked some of the data with extra scientific facts, but you still seem to recite the same numbers. But anyway, it doesn't really matter. But to me, the bottom line is that if I think most of us want our kids to live better, right? And if we want our kids to live better, then, of course, it's great to have even more certain numbers. But if we know that they for sure we live much better if we right now implement those solutions that we know we have, and that we know are going to make the world anyway a better place to live, then I don't really know why spend so much time and effort to quantify and who to trust and whatever. Rather, I would encourage everyone to focus their intention on looking at all the great things, what we can do, to fight climate change, to make our cities better so that we are not so reliant on the car, and make ourselves healthier by having the better and healthier diet, and implement more renewable energy, which is going to make us independent of even the Russia-Ukraine war and energy price volatilities, and make our products more durable. And just there's so many things which we can do, which we can definitely live better from. So for me, the bottom line is that yes, Misha, you're absolutely right, and it is hard to find whom to trust. But still, I think, if we rather focus on whom to trust, with regard to what are the good solutions to climate change, where we just cannot go wrong, that's still a safer way to go.

MISHA: For sure. We agree. I think we should be doing more. And it's tragic we're not doing a lot of those policy things. I think we all agree.

SPENCER: Thank you both so much. Really appreciate that. This was a really fascinating conversation.

DIANA: Thank you. I enjoyed it a lot and learned a lot from this. Thank you.

MISHA: And thanks so much, Diana, for doing this. I really, really appreciate you doing this. Thank you very much.

JOSH: After the episode we asked Diana if she could send us good papers or government reports that model the harm to humans or society from large amounts of warming, so that we could include them in the show notes. Diana replied saying, “I wish there were such papers or reports I could show you. I am including for the show notes a paper that shows why there are no such scenarios even exploring the natural science aspects. And without these, any super forecasts into the economic well-being or societal implications are so unfounded and completely guesses, only because if you read the attached chapter on just three degrees of warming, you will see that the planet will be so completely different that anyone who claims he knows what economy can survive under such conditions, let alone civilization, does not have a clue on how completely different a planet is would be in a, for example, seven degrees warmer world. I've also included for the show notes a recent paper on tipping points. If you read this, you will see why. Who could claim to quantify how our economy changes when most of our big cities and wealth, as a huge share of human wealth is along the coastlines, when most of our big cities in the world go underwater, when huge regions will not have drinking water parts of the year because glaciers disappeared, when there's no Gulf Stream, and Europe either freezes or dries out or both?”

[outro]

JOSH: A listener asks: What's a piece of work you're proud of that went under the radar or hasn't gotten as much attention as the ones you're best known for?

SPENCER: One example I feel is like that is our Theories of Worldviews that we put together, which I'm quite happy with. Basically, we spend a bunch of time thinking about what are the elements of a worldview? In other words, what are the different pieces that most worldviews have? They don't have the same values for these pieces, but they all have the same kind of structure and pieces, and then started thinking about how this structure applies to many different worldviews. And so, we have an essay about this. You can find them in the Clear Thinking blog with our Theory of Worldviews, and kind of we walked through many different worldviews and kind of explain how to apply the theory there.