One of the nation’s most respected (and harassed) scientists, Dr. Michael Mann, discusses the climate change tipping point and battling forces of denial.
In this episode
- Michael explains his natural desire to understand how things work
- Michael talks about his climate science research and the backlash he faced
- Colleen and Michael explore the important role scientists have to play as science communicators
- Michael discusses the strength he sees in the current breed of younger scientists
For many Americans, our first introduction to the idea that our climate is changing was presented to us with an unforgettable visual: the hockey stick graph. The long part of the stick shows us hundreds of years of relatively stable climate, with normal global average temperatures. The curved part represents global average temperatures over the last few decades—which have shot up dramatically.
Dr. Michael Mann was one of the leading scientists behind the hockey stick graph, when it was published in the late 90s. Since then, he’s been a favorite target of climate science deniers. He’s been harassed, hacked, and threatened. He’s had his research unfairly poked to bits in attempts to discredit him. But he’s stood by his work in the face of smear campaigns and phony controversies for decades now—and has been vindicated with recognition from the scientific community. Dr. Mann is a distinguished professor of atmospheric science, and the director of the Earth System Science Center at Penn State University. He joined me to talk about his introduction to climate science… how scientific knowledge is a slow process of accumulation… why it’s not enough for scientists these days to simply do their work… and what he would do with Wonder Woman’s Lasso of Truth.
Colleen: Michael Mann, welcome to the Got Science? Podcast.
Michael Mann: Thanks. Great to be with you.
Colleen: So our listeners may know you as one of the climate scientists who originally demonstrated the hockey stick curve, a graph showing evidence of the earth's rapid warming. So that was back in the '90s. Others may know you as one of the most harassed scientists in modern history, along with others. You've had death threats leveled at you. You've been sued by the former attorney general of Virginia to gain access to your private emails. You were even mailed fake anthrax. The list goes on and on. And I do wanna talk to you about all that today, but first I'd like to go back to the beginning. Why did you become a scientist?
Michael Mann: Yeah, I became a scientist because I loved solving problems. From the earliest days that I can remember I was always asking, anybody who would listen, questions, "You know, why is this this way?" I still recall I had an uncle who I would constantly pester about traveling at the speed of light. Finally, he gave me the book Jonathan Livingston Seagull and told me it would answer all my questions. Of course, it didn't, but I was always curious about the natural world, about the way things work and I always enjoyed solving problems, mathematical problems, what you might call scientific problems.
And so that led me to pursue a, degree in applied math and physics at UC Berkeley, and I went off to graduate school at Yale to study theoretical physics and then sort of realized that, there was this really interesting problem that required math and physics, the problem of modeling earth's climate, and that struck me as a fascinating problem where I could use the tools, the math and the physics that I'd learned to work on this really interesting problem that it turns out also has some pretty important societal implications as well, but that wasn't what drove my interest in climate. it was just this fascinating, huge, unsolved physics problem, and so that's what led me into the field of climate research.
Colleen: I've been reading your book "The Madhouse Effect," which is a collaboration with cartoonist Tom Toles and, full disclosure, I did read the cartoons first. On page one, you talk about science and how it works, so the many levels of scrutiny and checks and balances. So tell me a little more about the problem and process.
Michael Mann: Yeah, you know, the problem we were actually interested in, we were using what are known as proxy records. These are things like tree rings and corals and ice cores and lake sediments, natural archives that we can use to extend the climate record back in time. We only have about a century or so of widespread thermometer measurements and so to get a longer-term sort of view of how climate changes, we need to turn to these so-called proxy data. The project that I was working on at the time had to do with natural long-term cycles in the climate. It wasn't actually about climate change. It wasn't about human-caused climate change. I was interested in identifying long-term climate cycles and the instrumental record alone wasn't long enough to do that so that's why we turned to these proxy records and it was only really a by-product of that analysis where we decided to use those records to actually reconstruct climate patterns back in time.
And when we took a look at the result, we realized now that this work did have implications for human-caused climate change, because when you averaged the information over the globe to get a single number for each year, the average temperature, for example, of the Northern Hemisphere, where we had the most data, and you plotted that back in time, it became clear that the warming spike that we've seen over the past century really has no precedent as far back as we could go, at least a thousand years. And so, we published that work in the journal Nature, back in 1998. And in the article, we actually emphasized quite a bit the importance of these patterns for understanding natural climate variability, the El Nino phenomenon, and other things, how volcanoes influence the climate. There were all these other interesting problems that were really the primary impetus for doing these reconstructions in the first place.
But the curve that showed the average temperature of the Northern Hemisphere, which has come to be known as the hockey stick because of its shape, the blade of the hockey stick being the rapid warming of the past century and the handle being the longer term trend as you go back a thousand years, that took on a life of its own. That was the one sort of result in that article that got all the attention and suddenly I found myself in sort of the center of the larger, very fractious debate over human-caused climate change, because of the deep implications that this curve, the hockey stick had. It told a simple story, you didn't need to understand the physics of the climate system to understand what this graph was telling us, that there is something unprecedented about the warming that we've seen over the past century, and by implication, it probably has to do with us.
Colleen: What sort of review then did your research undergo?
Michael Mann: To have credibility in the scientific world. Findings have to be vetted through the process, the peer review process.
Colleen: By scientists.
Michael Mann: Right, where you submit an article to a journal, in this case, Nature, and it goes to other leading scientists in the field. Your work, your article is reviewed essentially by your competitors and that's a pretty tough process to withstand. They're looking for holes in your findings, in your arguments, and they provide reports to the journal. The journal decides if the reviews merit publication with substantial revision or if the problems that are identified by the reviewers, the issues are too great to overcome, they'll reject the manuscript, and Nature rejects the vast majority of manuscripts it actually sends out for review. And it only reviews a small subset of articles that it considers to be most significant. So that's a really tough vetting process and to come out at the other end, and to have your article published means that you have to have addressed any of the issues that were raised by the reviewers in a meaningful way.
And that's just the first step, because, the way science works, when you publish an article, that doesn't represent a new scientific understanding. It's one small increment in this larger foundation of what we know about the science. Very rarely does a scientific article substantially change our understanding. Typically, it incrementally adds to our scientific understanding, and it's through the accumulated weight of multiple peer-reviewed studies that all point in a similar direction that we acquire what we think of as scientific knowledge. Getting an article published in the peer-reviewed literature is the first step in establishing, you know, sort of an advance in the forefront of understanding, but that alone is not enough to build a robust scientific consensus. Scientific consensus rests on the existence of multiple studies that all come to a similar conclusion.
Colleen: This makes it difficult then to communicate to the public about, at what point we should really be worried, or really do something. I know, again, in your book you talk about this tipping point "Have we passed the tipping point? Are we near it?" I think it gives people some measure of knowing where they are in this process, Have we passed the tipping point, or are we about to?
Michael Mann: Yes. So the tipping point, what we might describe as dangerous and catastrophic and irreversible climate change, that is a question I often get from people. You know, are we there yet? Have we passed the tipping point? The answer is disappointingly nuanced because, in reality, there is no one climate tipping point. There are probably many and rather than thinking about dangerous climate change as a cliff that we go off at some level of warming, often described as two degrees Celsius, three and a half degree Fahrenheit warming of the planet relative to pre-industrial is where scientists who determine, we start to see the worst impacts of climate change.
But there isn't a cliff at two degrees Celsius warming. It's more like an ever down sloping highway, and the farther we go down that highway, the more treacherous it becomes. We wanna get off at the earliest exit we possibly can. In reality, dangerous climate change to me isn't a cliff. It's more like a minefield and we're walking out onto this minefield and we will certainly set off mines if we continue to walk out onto that minefield. And we don't know exactly where they are, all we know is that as we walk out onto the minefield, we subject ourselves to greater and greater danger and risk.
Colleen: it's admirable that you keep marching down this road. Because of your research, you've received death threats, you've received what looked like anthrax in the mail. Thankfully it wasn't. What did you do when you opened that envelope and did it make you think that you should get out of the field of climate science?
Michael Mann: There were times when it felt like it was too much and, you know, you start to question whether or not you signed up for all this. You know, when I got a degree in applied math and physics from UC Berkeley, went off to graduate school at Yale University, little did I think that I was sort of preparing for a career of battling these forces of denialism so there were some tough times.
And what kept me going was the support of my colleagues, my fellow scientists, especially one scientist for whom I have the deepest respect who came forward and provided words of encouragement, my good friend Steve Schneider, who's no longer with us. He was a great climate scientist and great science communicator, and I had a number of conversations with him, where he told me, "Look, you know, the fact that they're going after you like this tells you that, you know, what you're doing is important. You're hurting their client," is the way Steve would put it. The client, sort of in a metaphorical sense, the fossil fuel interests who were funding this. "You know this is inconvenient. Your scientist findings are inconvenient. They're having a real impact."
Though it isn't what I signed up to do, I really don't think that there's any more important thing that I could be doing with my life than trying to inform this discussion about what might be the greatest threat, the greatest challenge we face as a civilization. I feel honored to be in a position to inform that discussion. And so if you ask me if I had the choice to do it over, would I choose a different path? The answer would be no. I would choose the same path.
Colleen: How has this changed the way that you conduct your research? I imagine it's different.
Michael Mann: Yeah, if you're a climate researcher today, especially one who engages with the media and is involved in outreach and communication to the public, then you're gonna be challenged, you're gonna be attacked. It makes you all the more careful in your research. You wanna make sure it's bulletproof because you know that there are targets on your back and there are people who will look to discredit it in any way possible, you wanna make sure that your work stands up to the legitimate scrutiny of your fellow scientists and so I think it probably makes us more careful in the way we do science.
We double check our calculations. We wanna make sure that we've really gotten it right before we publish, and it also sort of reinforces this notion that, you know, your job isn't done when the paper is published because you still have to be out there trying to ensure that the findings and their implications are conveyed accurately and objectively to the public, and you have these forces of denial who are trying to spin research in ways that downplay the significance of climate change and the threat of climate change. And I wrote an op-ed a few years ago in the New York Times, the title of which was "If You See Something Say Something," borrowed of course from our Department of Homeland Security. But the point of the op-ed was really that as a scientists we really have to be out there communicating what we've found and what the implications are, because if we don't, if we're not out there then we leave a void that will be filled by other voices, vested interests who have an axe to grind, who have an agenda to advance, and that does a disservice to all of society.
Colleen: That's an interesting, perhaps new, world where a scientist has to also be an amazing communicator to the layperson and that's not easy to do.
Michael Mann: It's not a skillset that science necessarily selects for but I think, increasingly, we're seeing younger scientists who are coming into science today who are much more engaged in sort of that side of it, the communication and the outreach, I think, because it's sort of part of your upbringing today. You know, young scientists have grown up in the world of social media, on the online world, and I think that, because we have seen these concerted attacks against science, it's brought in sort of a new breed of scientists who wants to do science, but also wants to be involved in defending science. And I think that's... If you're looking for a silver lining, then that's certainly one.
Colleen: Mm-hm. So I have to ask this question. Your research has gone through incredible scrutiny by the scientific community. How do you deal with the climate deniers, the non-scientists who throw out these ridiculous assertions? Do you ever just wanna put your face in a pillow and scream?
Michael Mann: I think I probably have on occasion. You can ask my family, they've probably heard. You know, yeah, there are times, when it can be very frustrating. Not really because, you know, you're being attacked, you know, we've come to expect it and frankly most of the attacks are just so silly that they're not taken seriously by the people that we care about the most, our fellow scientists and policymakers who are engaged in a good faith effort to understand the evidence. But they do provide fodder for the sort of professional denialism, industry-funded denialists and front groups and organizations, funded by fossil fuel interests that spread misinformation and disinformation and the politicians, policymakers who sort of see themselves as essentially agents for the fossil fuel interests who fund their campaigns. The forces of denial at this point, in my assessment, are not engaged in a good-faith debate, because the basic science is in.
Colleen: What are you currently working on?
Michael Mann: So, believe it or not, still science is probably the thing I love doing the most. I love communicating the science as well. But what brought me into science, what got me into science in the first place was my love of doing science and I feel it also keeps me grounded. When I talk about the science and its implications, being on the forefront of the science sort of keeps me grounded in terms of what I know and how well I can inform the discussion. There are a number of different projects that I'm involved with at any given time. There are probably a half dozen. Probably the one I'm particularly interested in and sort of active in, is an effort to understand the linkages between climate change and extreme weather because there are still some scientific uncertainties in the linkages, how climate change, human-caused climate change is impacting storm systems and how it may be changing the jet stream in a way that gives us sort of the wacky weather that we've seen in recent years.
There is legitimate uncertainty in that area of science, and the implications of that area of the science are profound, because of course to the extent that climate change is exacerbating many types of extreme weather events. That's where we're seeing some of the greatest tolls, something like I think it was $300 billion in insured damages in the United States last year, just over the last year, by these unprecedented wildfires, superstorms, floods. Understanding that linkage and being in a better position to assess how much worse it'll get if we continue on the course that we are on, there's a lot of important science to be done in that area, and so that's one of the areas where I'm doing quite a bit of work. Also, and specifically, the phenomenon of hurricanes and how climate change is impacting hurricanes and changing hurricane characteristics together with sea level rise is impacting coastal risk for, you know, the East Coast of the US, including, you know, cities like Boston and New York City, but for the rest of the world as well.
Colleen: So if you could have one superpower, what would you want?
Michael Mann: It would be Wonder Woman's golden lasso because I would wrap it around our politicians and force them to tell the truth when it comes to climate change and the impacts that it's having.
Colleen: That is an excellent superpower. If I could grant it I would. What would you say to early career scientists to encourage them?
Michael Mann: Yeah, I would say, have courage. Know that if you're doing cutting-edge science, in any field where the findings of science might collide with powerful special interests, There are so many examples of scientific research, be it biology or chemistry or physics basically, like the physics of climate change, where the science that we do eventually has implications that may prove inconvenient to powerful special interests, be they tobacco interests, or the fossil fuel industry or the, you know, the chemical industry. And we have to expect that they will push back through any means available to them and often that involves attacking scientists. Attacking the science itself by trying to discredit the messenger, the scientist. So have courage, and know that if you're being attacked by these sorts of folks, it's not because you're doing bad science, or you're a bad person, it's because you're doing good science that really has implications, implications that are troubling to some of these vested interests, and know that you have the backing of the scientific community.
And one of the things that has made me optimistic about where we're headed is just over the course of my career, how the scientific community has really started to recognize that they're in a fight with bad faith actors who are trying to discredit science, and they need to be more organized, the scientific community needs to be more committed to positive outreach and communication, and to provide resources to scientists who are willing to do that, and to protect them, whether that's in the legal realm or simply in having an army of scientists who are out there trying to speak truth to power. And this is a worthy battle and if you're looking for a worthy battle, then the battle to inform the public about science and the implications it has, there's no worthy battle in my view to be involved in, and so I hope younger scientists recognize that. I think they do. I think I recognize that in the younger scientists who are coming into this field, sort of a new breed of scientists.
Colleen: Michael Mann, thank you so much for joining us here at the Got Science? Podcast.
Michael Mann: Thank you. It was great.
Sidelining Science: Shreya Durvasula
Editing: Omari Spears
Music: Brian Middleton
Research and writing: Pamela Worth
Executive producer: Rich Hayes
Host: Colleen MacDonald