Catalyst Summer 2018

“No Worthier Battle” than Defending Climate Science

Interview with Michael Mann

Michael Mann is a distinguished professor of atmospheric science and the director of the Earth System Science Center at Pennsylvania State University. He is the author of more than 200 peer-reviewed and edited publications, numerous op-eds and commentaries, and books including The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (Columbia University Press, 2012) and, with cartoonist Tom Toles, The Madhouse Effect: How Climate Change Denial Is Threatening Our Planet, Destroying Our Politics, and Driving Us Crazy (Columbia University Press 2016).
Photo: Dave Bowman/NASA

How did you become a climate scientist?

Michael Mann: From the earliest days I can remember, I was always asking questions of my parents—and my other relatives, and teachers, and anybody who would listen. I was always curious about the natural world, about the way things work, and I always enjoyed solving problems.

So that led me to pursue a degree in applied math and physics at the University of California–Berkeley, and I went to graduate school at Yale University to study theoretical physics. And then I realized there was this fascinating, huge, unsolved problem that required math and physics: the problem of modeling Earth's climate. And that's what led me into the field of climate research.

You’re well known—perhaps unfairly, considering the breadth of your work—for your collaboration on the famous “hockey stick” graph depicting global average temperatures over time. What are the origins of this graph that has given you so much grief from climate change deniers?

Michael Mann: The project I was working on at the time had nothing to do with climate change initially; it had to do with long-term climate cycles. To identify these cycles, we used tree rings, corals, ice cores, and lake sediments—natural archives we can use to extend the climate record back in time.

As a by-product of that analysis, we decided to use those records to reconstruct climate patterns from hundreds of years ago. And when we did, we realized that this work had implications for human-caused climate change. Because when we plotted average temperatures far back in time, it became clear that the warming spike that we've seen over the past century has no precedent as far back as we could go—at least a thousand years.

We published that work in the journal Nature, back in 1998. 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.

Why do you think this one graph gained so much traction?

Michael Mann: It told a simple story. You didn't need to understand the physics of the climate system to understand that there is something unprecedented about the warming we've seen over the past century.

It was the one result in that article that got all the attention. And suddenly I found myself in the center of the larger, fractious debate over human-caused climate change, because of the deep implications the hockey stick had.

You might be the scientist most frequently maligned by those who deny that climate change is real, caused by humans, and a serious problem. Why do you think your work has received so much backlash?

Michael Mann: There have been coordinated and well-funded efforts by fossil fuel interests and their various front groups to discredit climate scientists, and scare us so we would stop participating in the larger public conversation. I certainly was among several scientists who were subject to these attacks.

What they're trying to do is obscure the scientific consensus, and fool people, and provide fodder for politicians to do the bidding of fossil fuel interests rather than what's right for the constituents they're supposed to represent. That can be frustrating, to see politicians repeating these debunked talking points that have been focus-grouped and poll-tested. That's why they're using them: they're false, but they have this veneer of credibility and that's all that they think they need.

How have these attacks affected you?

Michael Mann: There were times when it felt like it was too much, and I started to question whether I signed up for all this. You know, when I went off to graduate school, little did I think that I was preparing for a career of battling these forces of denialism.

However, I don't think there's any more important thing I could be doing with my life than trying to inform this discussion about what might be the greatest challenge we face as a civilization. Given the choice, I would choose the same path.

In your book The Madhouse Effect, you mention that people frequently ask you about a “tipping point” for the climate, after which the damage caused by unchecked carbon emissions becomes irreversible. Do you believe there is such a point?

Michael Mann: My answer is disappointingly nuanced, because, in reality, there is no one climate tipping point. There are probably many. Dangerous climate change to me isn't a cliff. It's more like a minefield that we’re walking on, and we will certainly set off mines if we continue. 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 danger and risk. And that's why we have to stop marching onto that minefield—by bringing down our carbon emissions dramatically.

What would you say to early-career scientists to encourage them?

Michael Mann: Know that if you're doing cutting-edge science in any field where the findings might collide with powerful special interests, you have to expect that they will push back through any means available to them. Often that involves attacking scientists. So, have courage, and if you're being attacked by these sorts of folks, it's not because you're doing bad science.

If you're a climate researcher today, especially one who engages with the media and communicates to the public, then you're going to be challenged. You’ll want to make sure your research stands up to the scrutiny of your fellow scientists, because there are people who will look to discredit it in any way possible.

The battle to inform the public about science and its implications—there's no worthier battle, in my view, to be involved in. It's not a skill set that science necessarily selects for, but I think we're seeing younger scientists today who are more engaged in communication and outreach. If you're looking for a silver lining, then that's certainly one.

Hear more about Michael Mann's work on the Got Science? podcast: