Michael E. Mann, noted climate scientist and Distinguished Professor of Atmospheric Science at Pennsylvania State University, sat down with Woods Director Chris Field to discuss his groundbreaking work on understanding global warming and the subsequent politicization of those scientific results.
Edited excerpts and video of the Nov. 29, 2018 conversation are below.
People had been wondering for a long time if it is warmer now than it used to be and you’re really the person who figured that out. What was the process and aftermath of coming up with a statistically robust record of Earth’s temperature going back 1,000 years?
Mann: What drove us to make these forays into reconstructing past climates with proxy data was an interest in natural climate variability. But when we assembled those data and we formed this reconstruction of past temperatures, we did the least scientifically interesting thing you could do, which was to average over them to get a single number for the average temperature for each year.
When we plotted that out we realized that the study maybe does have some implications for human-caused climate change. What we found was that the recent warming spike of the past century has no counterpart as far back as we could go a thousand years. It was published in 1998 which was the warmest year on record for the instrumental data that we have. What we were able to conclude was that not only was 1998 the warmest year on record for the past century, it was probably one of the few if not the warmest years as far back as we could go a thousand years. The warming trend that we've seen has no precedent as far back as we could go.
How did this discovery affect your professional life?
Mann: I suddenly found myself, a Berkeley physics and applied math major, in the very center of the most contentious political debate that we've possibly ever had as a society, the debate over human caused climate change and what to do about it. It isn't the path that I charted out. I envisioned a career where I would be in an office at my computer solving problems, crunching numbers. That's what I love doing. But when the hockey stick became this icon in the climate change debate, that was no longer an option. Whether I liked it or not, as the principal author, I became this public figure and I had to decide what I was going to do with that. Ultimately, I did decide to embrace that and use that as an opportunity to inform this conversation over what is potentially the greatest challenge we face as a civilization. I have no regrets. I can't imagine devoting my life to anything more important than that, but it's not what I set out to do by any stretch of the imagination.
How long was it between the time the paper was published and the attacks started?
Mann: Things started almost immediately but I would say the critical development wasn't so much the publication in 1998 of the original hockey stick or a year later in 1999 with the extension back a thousand years, which is the more familiar hockey stick curve that people see these days. It was probably when it was featured in the summary for policy makers of the 2001 IPCC report. This is something that politicians, journalists, and people around the world read. It has a fundamentally important impact on the discourse over climate change. So, when the hockey stick curve was Exhibit A in the summary for policy makers of the 2001 third assessment report, which I had worked on, it was now sort of the poster child of climate change and that made it an irresistible object of attack by the climate change denial machine and that's really when things ramped up.
The hockey stick is still this icon and it still attacked as if they could bring down the hockey stick. It's this cynical principle that if you can take an icon and you can discredit it, then you can claim to undermine the entire case for concern about climate change as if it hinged on one 20-year old study by one postdoc.
How do you reach people with messages on climate change given the political contentiousness of the topic?
Mann: In today's hyper-partisan atmosphere where people have become so balkanized and tribal in the way they think about matters of objective truth like the existence of climate change or as John Oliver would point out, the existence of hats or the owls, apparently, we can't agree on the basic facts anymore. That requires us to look for inventive ways to reach people whose front door is closed. You're not going to barge through the front door with facts and figures and graphs. That's closed. So, you look for the side door and humor and satire is one of those side doors. It's one of those ways of reaching people through alternative avenues that maybe are still accessible. I think it's part of why in today's hyper-partisan political atmosphere, our hardest-hitting commentary often comes from our comedians.
Can you encapsulate where you think we are in the understanding of the climate challenge and in actually being able to deploy meaningful solutions at scale?
Mann: The stages of climate denial are evolving from ‘it's not happening’ to ‘it's happening but it's not due to human activity’ until the final stage of denial which is ‘yeah it's happening, it's caused by human activity, it's bad, but there's nothing we can do about it’. Which is wrong. I think we've reached the point where the impacts of climate change have become so obvious to the person on the street that no politician can try to seriously deny that something is happening.
The game now is to deny that it's a problem and to argue that if we do something about it, it will destroy the economy, when just the opposite is true. Inaction is the greatest threat to the economy and by the way the real growth industry is renewable energy and the countries that recognize that are the ones who are going to win out in this international economic competition over the next century.