Abstract
Professor Michael Mann is one of the world’s leading climate scientists and best known for his work on historical temperature trends and hemispherical climate reconstructions, including the iconic ‘hockey stick’ graph of long-term temperature variations. As a result of his work, Professor Mann became a central target of criticism from conservative politicians, industry groups and the climate change denial industry. The following edited interview was conducted in October 2012.
Michael thanks for speaking with us. Your recent book The Hockey Stick and the Climate Wars (Mann, 2012) is a fascinating insight into the increasingly politicized world of climate science. If we could begin with a bit of background, when did you first become convinced about the human impact on climate change?
Over the course of my PhD studies which took me through the mid-1990s the scientific community had really evolved quite a bit over a period of just a few years where the climate models were becoming far more sophisticated than the early models that climate scientists worked with. More and more data were coming in that was telling us that we were, in fact, seeing the continued warming of the planet. In 1995 the Intergovernmental Panel on Climate Change, for the first time, concluded that there was indeed a discernable human influence on the climate and that was based on work using methods called fingerprint detection methods, which basically took the predictions of the models, looked at the observed patterns and the data, and asked whether those observed patterns were consistent with what the models say the response to natural factors might be, or whether or not we needed the added role of human beings to explain the observed patterns.
The answer to the question was the latter, that we really could say that not just the overall warming of the globe, but the pattern of that warming was inconsistent with natural climate variability. There was a detectable human influence on the climate. So I was sort of coming of age as a scientist at precisely the time that the scientific community was moving into a position of consensus on this point.
It wasn’t a surprising conclusion to me. I suspected that increases in greenhouse gases were already having an imprint on our climate. It would be surprising were it not the case because the underlying physics is very basic. The greenhouse effect? That’s nearly two century old science—physics and chemistry, and the fact that we had been increasing the concentrations of these gases, that was indisputable based on the Keeling measurements back through the 1950s and ice core measurements even further into the past. We knew we were elevating concentrations of these gases well beyond pre-industrial levels. We knew that the greenhouse effect was very fundamental physics. So what would have been difficult to understand would be, in fact, if the globe hadn’t been warming in response and it just required enough information to say that the warming had taken us outside of that envelope of variability where natural causes could be a plausible explanation.
So interestingly enough, my own work, my PhD work at the time, was much more geared toward natural climate variability and even though there was a consensus now that humans were warming the planet, there were still open questions about precisely what changes in climate we could attribute to that. Were all of the trends due to increased greenhouse gas concentrations or were natural factors also playing a role perhaps with some of long-term changes in climate? My PhD project was actually focused on trying to tease out some of those long-term natural factors.
In your book you describe how Republican politicians like Senators Barton and Inhofe, seized on your research and the image of the hockey stick as a central focus for their attack on climate science. Do you think there was anything innate in the hockey stick image that explains the vitriolic nature of the attack you encountered from politicians who rejected climate science?
Yes I think there is. So we did end up producing this curve, the hockey stick (Mann et al., 1998, 1999). But scientifically it was relatively uninteresting to us. What we thought was most interesting was teasing out spatial patterns—looking at the signature of past El Nino events, looking at the response around the world to past volcanic eruptions—these sorts of questions. Whereas producing a single number—the average temperature over the Northern Hemisphere—is less scientifically interesting. You can’t address some of those interesting questions about climate dynamics. But the hockey stick curve did yield a very compelling and simple depiction of how unusual the changes in climate that we are seeing today really are in this longer-term context. And it became an icon in the climate change debate when it was featured in the summary for policymakers, the most high profile part of the 2001 IPCC report (IPCC, 2001).
It took on a larger than life role in the climate change debate. I think it represented a real challenge to those who continue to deny the reality of human-caused climate change because you didn’t need to understand the physics of how a climate model works. You didn’t need a whole lot of technical background to be able to look at that graphic and understand what it was telling you: that there is something very unusual about the changes that are taking place today, and by inference, probably means it has something to do with us.
So I think it really represented an inconvenient scientific result to the forces of climate change denial. And so they decided to target this icon—the hockey stick—and to try to bring it down through any means possible, which included increasingly political and personal attacks against me and my co-authors.
So how did it feel having to defend your research from sceptical politicians and finding yourself in the middle of a media spotlight?
That’s part of what I hoped to convey with the book—to take the reader through that personal journey and to understand at least a little bit of what it feels like. I talk about how in high school my idea of a fun Friday night was hanging out with my friends and eating pizza and doing computer programming to try to solve problems on a computer. So I was a real computer nerd. I loved science and math and that’s why I went into physics as an undergraduate at UC Berkeley. I majored in physics. I really thought I was going to go on to a career in theoretical physics where I’d be behind a computer screen working on interesting but abstract problems … as far away from the public fray as one can imagine. I was very comfortable with the idea of being a scientist in a laboratory working on what I loved doing, i.e. using mathematical and computer methods to solve problems. That ultimately took me in a direction where I found myself faced with a choice in graduate school: in the late 1980s it was actually pretty difficult to find funding to work on basic theoretical problems in physics because there were huge cutbacks in the federal budget for physics research.
They had cut the budget for the so-called ‘superconducting super collider’ which was going to provide all sorts of funding for physicists. So there was this mass exodus from physics at the time. I saw that there were people in the Department of Geology and Geophysics at Yale University, where I was doing my PhD in physics at the time, that were using math and physics to work on the problem of understanding how Earth’s climate system works. To me that sounded like a huge, fascinating big picture problem that I could really sink my teeth into and I could bring my math and physics background to work on this exciting problem. So, to me, it was just an exciting problem to work on. The furthest thing from my mind at the time was all of the politics that surrounds the issue of human-caused climate change.
So when you moved from that world and suddenly were in this more public world of climate change debate, how did you deal with that?
I guess fortunately, depending on how you want to look at it, this all unfolded over a timeframe of more than a decade, which allowed me to develop over time a thicker and thicker skin as the attacks became increasingly concerted. As the hockey stick became engrained as this icon in the climate change debate it became more and more of a direct target for climate change deniers.
The effort to deny climate change represents a very organized and well-funded effort. The fossil fuel industry did what the tobacco industry did decades ago, questioning the science linking the use of their product to human health ailments. They were using the tobacco play book and they were using all the tools, the considerable money that they had available to them, the resources that they had, to create a lavishly funded and organized campaign to discredit climate science.
I found myself at the centre of that campaign because of the role that the hockey stick had played in the climate change debate. It’s rather ironic because the hockey stick never was and never will be truly a central line of evidence for the reality of human-caused climate change. That evidence is based on fundamental physics and chemistry, irrefutable measurements about the way that we’re increasing the levels of greenhouse gases, thermometer measurements that tell us that the Earth is indeed warming as we expect it to. The hockey stick is not central to that argument but it is a very visual and compelling graphic indication of how we are changing the climate. That’s really why it became a target. Those looking to discredit it believed that they could build this straw man, could fool the public into thinking that all of our understanding of human-caused climate change was a house of cards that rests on a single hockey stick. Now nothing could be further from the truth but that was the straw man they were trying to create.
Increasingly we found ourselves on the receiving end—I, in particular, found myself at the receiving end of a very well-funded smear campaign aimed primarily at discrediting me and my work. As time went on, it wasn’t just ultra conservative media outlets and fossil fuel industry front groups and their paid advocates who were attacking me. Pretty soon I found myself in the crosshairs of attacks by influential politicians.
Did that surprise you, because when I read your book it sounded almost like something out of The Crucible?
It just felt so surreal … that it didn’t feel as personal as it might otherwise have. I was able to step back and say there’s something larger that’s going on here. Fortunately I had trusted colleagues who were pillars of the scientific community who advised me and came to my support when I needed it. Stephen Schneider, one of the leading climate scientists, sadly passed away a few years ago and we all miss him greatly. He was a great climate scientist but he was also a magnificent communicator of the science—and someone I’d idolized. Early on when the attacks against me were ramping up, he came to offer me advice and to provide support and to provide me some perspective. He said, ‘look, they wouldn’t be going after you in this way if your work wasn’t important’, if it wasn’t—as he put it— ‘harming their client’ (their client being the fossil fuel industry). He and others like him were able to provide support and give me a little bit of perspective and that really helped me deal with these attacks.
For those people who haven’t read the book, could you perhaps give one or two examples of the more memorable, or perhaps forgettable, experiences in terms of attacks on you and your research?
Sure, I mean, there are many and I’ll choose a few which I think are illustrative of the sorts of things that I, and frankly, other climate scientists have had to endure. Back in, I think it was 2003, our work was attacked in a sort of pseudo scientific journal. It was a journal whose editor had actually said that she chooses to publish papers primarily based on her political agenda, which was an agenda to oppose the regulation of greenhouse gases.
So in this sort of pseudo scientific journal there were two non-scientists associated with industry think tanks and fossil fuel industry interests and they published this paper attacking our work. It was a total hatchet job. I mean, there was no validity to it whatsoever and it would be easy enough to refute down the road but we didn’t have months or years.
What happened was that this paper was published on the eve of a critical vote in the US Senate and within days of the paper being published there was an op-ed published in the largest circulation newspaper in the US, USA Today. The op-ed was published by a representative from a fossil fuel industry front group. So somehow USA Today had granted an op-ed to an advocate for the fossil fuel industry to write a hatchet job attack against us and our work based on this paper that had just appeared in a pseudo scientific journal. Within days of this all happening, Senator James Inhofe of Oklahoma had declared human-caused climate change was the single greatest hoax ever perpetrated on the American people. It might be relevant that he’s the single greatest recipient of fossil fuel money in the US Senate. He used all of this to attack us on the Senate floor as they were discussing this key Senate bill, I think it was called the Climate Stewardship Act. It was co-sponsored by a Republican John McCain and a Democrat, Joe Lieberman, and this was used to distract the entire US Senate and to try to discredit the science of climate change on the eve of this critical vote.
The bill ended up going down in defeat. It was fairly close and most likely the manufactured controversy around our work probably didn’t sway many voters one way or the other, but it was indicative of just how nasty and how concerted and focused the attacks on my work, and me specifically, were becoming.
I was amazed reading your description of the ‘Climategate’ incident in which climate scientists emails (including your own) were leaked to the media. It seems to have been very well manufactured and timed for maximum effect. What were your reflections on these groups that were looking to manufacture controversy at every opportunity?
Yes it’s funny, there’s a website that I co-founded with my colleague Gavin Schmidt back in 2004 called Realclimate.org and it’s a website aimed at debunking some of the myths about climate change. It’s run by 10 or so climate scientists who are active researchers in the field of climate science. A few years ago we published a piece on Real Climate called Thank you for Emitting which was an obvious take-off on Christopher Buckley’s book Thank you for Smoking—a very insightful look at the industry-funded disinformation campaign that was used by the tobacco industry to thwart efforts to regulate tobacco products for decades and probably cost a toll in human life in the millions.
In the epilogue of my book I actually use that as an example, because that industry-funded disinformation campaign clearly took a great toll in terms of human life. However, there was a report that just came out recently showing that the likely impact of climate change if we don’t confront this challenge, and we just pursue business as usual and allow the globe to warm by several more degrees, will be an even greater toll in terms of human life and suffering (DARA and Climate Vulnerable Forum, 2012). So arguably, the forces of disinformation behind the climate change denial disinformation campaign are every bit as much villains as those who sought to hide the deadly effects of tobacco products.
In Australia we’ve had instances of climate scientists receiving personal threats. It’s got very heated. Has any of that happened to you personally?
In fact, frankly, what has happened in recent years in Australia I think is a direct result of Australian climate change deniers using precisely the same play book that they have been using in the US. For several years now climate scientists in the US have been at the receiving end of death threats, of actionable threats of violence. I recount in the book having received a few years ago an envelope that had a white powder in it . The Federal Bureau of Investigation had to come in and investigate—send this stuff off to a lab to have it tested to see if it was harmful. Not just I, but my colleagues would have been exposed to this had it been the real thing. Fortunately it was just corn meal. But the intent was clear (and by the way, the sender had committed a felony offense).
I’ve had death threats. I’ve had thinly veiled threats against my family made. I have had campaigns to try to have me fired from my job. And the interesting thing is when you trace it all back, a lot of it originates with a small number of players, a small number of front groups and organizations who derive their funding from a small number of deep-pocketed interests. The Koch Brothers in the US, the Scaife Foundations and various other fossil fuel industry front groups have provided the funding for the individuals and the organizations that are behind essentially all of the attacks that I’ve been at the receiving end of.
They use talk radio and use the media megaphone that they have available to them and on the internet, for example conservative leaning media outfits including the Murdoch empire. They use those outlets to foment attacks against climate scientists using heated rhetoric. They paint us as villains who are trying to take away people’s jobs and their liberty. Now the intent, no doubt, to incur the ire of people who might be disaffected, might have been adversely affected by the downturn in the economy, people who are looking for a scapegoat to blame things on. Here we have these mouthpieces telling them that it is those climate scientists they should be blaming this on. In some cases—for example Rush Limbaugh, Glenn Beck in the US—they tell their listeners that we deserve to be killed. They know that this rhetoric may indeed trigger an irrational response on the part of some of the millions of viewers that are listening.
This has been going on for some time in the US. My colleague Ben Santer had experience of this sort way back in the mid 1990s. His work played a prominent role in the second report of the IPCC which for the first time said that there was a discernable human influence on the climate. Ben’s work was fairly central to that conclusion. And so he was subject to efforts by professional climate change deniers to vilify him. A member of Congress from California, Dana Rohrabacher (who, not surprisingly, was closely tied to fossil fuel interests) tried to have him fired from his job. One morning he found a dead animal on his doorstep with a yellow Hummer driving off.
So this has been going on for some time in the US. It’s been very troubling to see the Australian climate change denial machine using precisely the same tactic now against my Australian colleagues. It’s absolutely disgusting.
I’m guessing that the vehemence, the dirty politics, the dirty tricks must have been quite a surprise because this is very different from the mathematical science and physics that you’re used to. So over that ten years you must have developed new skills and it must have been quite a learning experience
It was. There was a steep learning curve and, like I said before, I developed a thick skin and it was a matter of trial by fire to learn how to defend myself and to try to acquire some of the skills necessary to defend oneself against these sorts of attacks. I think there are some unintended consequences of the attacks that climate scientists have been subjected to over the years and one of those consequences is that I think we are actually becoming better as a group at communication, at being public messengers, at defending ourselves against attack and understanding that the methods of the disinformation industry and fighting back against them. Very staid organizations like the National Academy of Sciences here in the US have issued extremely stern denouncements of the industry-funded attacks against climate scientists and climate science.
So I like to think that, to some extent, the attacks against us have backfired. The scientific community is now speaking out with greater authority and urgency about the importance of having a real discussion about the issue of climate change and what to do about it.
Given that you’ve been at the pointy end of the science-politics interface for some years, what’s your take on the lack of political engagement on this issue? What do you think is driving that?
I frankly think it’s fear. Fear among those who otherwise might want to move the agenda forward in dealing with the threat and dealing with the problem of climate change. Fear that they too will be subject to the attacks funded by tens of millions of dollars of fossil fuel industry money aimed at vilifying anybody who takes a prominent role in warning the public of the threat of our continued reliance on fossil fuels.
It’s reached the point where the Koch Brothers who are the main funders of the so-called Tea Party movement in the US—a libertarian movement aimed at basically blocking government intervention, and blocking any impediments to laissez-faire capitalism—have actually targeted politicians, including politicians within the Republican Party. So there’s a split now within the Republican Party between the Tea Party faction who are opposed to essentially any regulation, and more moderate Republicans, the old school pro-science, pro-environment Republicans. There used to be a lot of them especially in New England where I grew up, who recognized that there was a good faith debate to be had about policy solutions. They would advocate for conservative approaches to dealing with climate change and that’s perfectly reasonable. But now that party is being overtaken by an extremist faction that wants simply to deny the problem exists. They seek to deny established science, whether it’s denial of climate change, or denial of human evolution. And what organizations or individuals like the Koch Brothers have done is pour money into the campaigns of Tea Party candidates targeting fellow Republicans who expressed a moderate view on issues of the environment and on issues of climate change and energy policy.
They have poisoned the discussion by using their resources to eliminate Republicans who would consider reaching across the partisan divide to engage in good faith discussions of how to contend with the climate change threat, arguably the most important challenge human civilization has ever faced.
By contrast, there is a growing literature on corporate environmentalism which highlights companies which are genuinely progressive on this issue. They accept the science and they introduce practices that aim to reduce carbon emissions. Have you encountered such companies and do they reach out to the scientific community at all?
They do and I think ultimately that may be an important part of this battle. Part of why we will confront this challenge is that there are a lot of smart people of conscience in industry who are at the top levels of governance of many of the major corporations, and they get it. They’re smart people. They’re well read and they know that climate change isn’t a hoax. And like any of us, they care about the world they leave behind for their children and grandchildren. The ‘adults at the table’ of the corporate world are increasingly reaching out to scientists, at least in private discussions. They do convey concern about this issue and they talk about wanting to move forward when there’s an opportunity to do so.
Certain industries like the insurance and the reinsurance industries stand to lose out greatly as damages continue to increase because of climate change-related disasters. These folks understand that we need to do something about the problem. The last few years have been difficult times economically. So threats that seem more distant are easily subjugated relative to ‘bread and butter’ issues that folks are dealing with like finding a job and putting food on their tables.
I think there is reason for hope that as the economy continues to recover and we find ourselves in a better economic environment, that there will be the will to tackle this problem. It is not going to go away and it’s going to compound every other problem we face whether it’s national security, human health or our economy for that matter. If we don’t deal with climate change we are going to see detrimental impacts across all sectors of society.
So I think we’re going to find the will to attack this problem. The worry of course is that we wait too long. There is an urgency here. The decisions we’re making right now with our fossil fuel emissions are leaving a legacy of decades and centuries in terms of the climate change that we’re locking in. So there is an urgency to dealing with this problem now.
I know a lot of your research has looked at the paleoclimatic history of the world. However, in terms of your personal attitudes do you find yourself looking into the future and trying to visualize what might be?
One of the things you actually learn by studying the paleoclimate record is that there have been large changes in climate in the past. If you go back 100 million years ago to the early part of the Cretaceous period, we know greenhouse gas concentrations were higher than they are today, several times higher perhaps. That was because of very long-term changes in the Earth like the movement of plate tectonics, the movement of the continents. Very slow long-term changes that do regulate the composition of the atmosphere on time scales of tens of millions of years.
What is unique about what we’re seeing right now is really the rate of change. We are changing the composition of the atmosphere and we are changing the climate at a rate that’s greater than anything we have seen in the past. Evolution has not prepared human beings and other species to evolve on these sorts of time scales. So the danger is not so much the magnitude of the changes as the rate at which they are happening.
The danger is that we will outpace our adaptive capacity, the capacity of plants and animals, and ecosystems to change their pattern of behaviour in response to a changing environment. Studying the past gives one the perspective necessary to appreciate just how dramatic an experiment we are playing right now with the Earth. It is an unprecedented experiment and a very dangerous one because, after all, we only have one Earth. If that experiment goes awry we don’t have a ‘backup Earth’ to turn to. So studying the past gives us a sense of why we need to be so cautious about continuing with business as usual, continuing with the course that we’re on.
In terms of the unprecedented pace of change in our climate, does that temper your optimism in terms of what’s possible over the next 30 or 50 years? I mean that latest Artic ice loss data is quite frightening. This suggests it may be too late to reverse this trend?
If you take a sober look at the impacts of climate change as they’re unfolding, as you allude to, in certain cases the changes are happening even faster than we projected them to. Ironically, my fellow climate scientists and I are often called ‘alarmists’ by our detractors. Yet the climate model projections have, in many respects, been too conservative and have under-predicted the rate of change. Nowhere is there a better example than the massive decline in the extent of summer Arctic sea ice. Now that poses all sorts of challenges for the Arctic ecosystem. It has implications for the rest of the global climate as well because the Arctic is our refrigerator here in the Northern Hemisphere. It helps keep summers cool over North America. Now we’re losing that refrigerator.There are other examples. The loss of ice from the ice sheets is proceeding faster than the models projected. That has implications for global sea level, causing it to rise even faster than we have projected it to.
We try to make our best estimate of what’s the threshold beyond which we really start to commit to the most dangerous changes in our environment. There’s not a complete consensus but some degree of agreement that we’re probably talking about something like 2 degrees Celsius warming relative to pre-industrial. We’ve already warmed one of those degrees Celsius and we have at least another half a degree that’s locked in just because of our historical emissions. The climate system has inertia so it’s going to continue to warm up even in response to past emitted CO2, so that means we’ve got another half a degree in the pipeline. That gives us a total of 1.5 degrees C warming relative to pre-industrial. Now if 2 degrees C is the threshold beyond which we see widespread, dangerous climate change impacts, we obviously don’t have a whole lot of wriggle room. If we bring our emissions to a peak within a few years and then get them down fast enough, we can probably limit our chances of avoiding the dangerous 2 degrees C limit to 50:50. This underscores the urgency. We don’t have a whole lot of time left to get our emissions under control if we are going to avoid crossing that threshold with any degree of certainty.
So it isn’t too late. There still time to right the ship, to steer clear of that metaphorical iceberg that we’re heading towards. But there isn’t a whole lot of time!
One final question, how do you see the future of the climate change debate unfolding, and to what extent does a future vision of a climate-shocked world act as a spur to your own research and writing?
As I allude to in the epilogue of my book, I see it as part of my duty as a scientist studying climate change and its potential impacts to make sure that the debate about ‘what’ to do is informed by an honest and sober assessment of what the science has to say. The way I see it, there are multiple potential futures. It is sadly all too easy to imagine a future where we did not rise to the challenges, where the forces of disinformation and denial prevailed, and effectively sabotaged efforts to reduce fossil fuel emissions and avoid catastrophic changes in climate. But it is also easy to imagine a future where the voices of reason prevail, and we engage in the difficult but essential task of transitioning away from our reliance on fossil fuels toward renewable clean energy sources. I am an optimist, and—call it faith if you like—I believe that we will choose the latter course.