Mann enough ‘His ‘hockeystick graph’ became the defining symbol of man-made climate change – and made him a special target of the fossil-fuel lobby’ ‘If you as a scientist share the stage with an industry-funded denier, you are implicitly telling the audience that these are two equally credible voices – and they’re not’ John Gibbons interviews Michael Mann Michael Mann is one of the world’s leading climate scientists. He is director of the Earth Systems Science Centre in Penn State University and has been a lead IPCC author since 2001. His ‘hockey stick graph’ became the defining symbol of man-made climate change – and made him a special target of the fossil-fuel lobby. He is author of ‘The Hockey Stick and the Climate Wars’, an insider’s account of the murky world of climate denialism. Mann was implicated in the so-called ‘Climategate’ hacking affair in 2009, but was exonerated of all alleged wrongdoing by several independent investigations. JG: Mike, you’re best known for your work on the Hockey Stick. Can you tell us about it, why it’s so important, and why it gets you into so much trouble? MM: The Hockey Stick is this graph my colleagues and I published a decade and a half ago depicting how temperatures, specifically over the northern hemisphere, have changed over the past 1,000 years. We used information from tree rings, ice cores and coral records, what we call climate proxy data. We know the globe has warmed by about a degree C over the past century but the question of how unusual is that warming requires us to go back in time. The record shows relatively warm conditions around 1,000 years ago, a steady, slow cooling trend into the 1900s – and then an abrupt warming over the past century. The shape of that curve is like a hockey stick…what it indicates is that the recent warming really is unprecedented as far back as we can go. This curve became iconic in the climate-change debate – it became a potent symbol in the larger debate over human-caused climate change, and it thus became an object of attack by those looking to discredit the case for concern over climate change. Climate deniers felt if they could ‘take down’ the hockey stick, then somehow the case for concern over human-caused climate change would collapse. Of course, that’s silly because there’s so much other evidence. JG: Why do you think climate science has become such a red-hot focus of controversy? In other scientific areas, the controversies are in the (peer-reviewed) journals. Why is this one on the street? MM: The fact is that any time you see the findings of science come into conflict with powerful vested interests, they’ve done their best to try to discredit the science and the scientists. Take tobacco, industry documents actually contained the phrase “doubt is our product”. They manufacture doubt when it comes to scientific findings that pose some potential threat (to their profits). Fossil-fuel interests are pouring in tens of millions of dollars here in the US to discredit the science of climate change, and to discredit arguments for renewables and clean energy. The Koch brothers for instance are funding both. JG: If the more serious projections coming from climate science (up to 4 degrees C warming by mid-century) are borne out, there’s no future for anybody. Is it not a puzzle that the so-called deniers somehow believe that the impacts won’t affect them? MM: Denial takes many forms. Those who are orchestrating the disinformation campaign at the top, one might imagine are fairly cynical – it’s quite clear that the fossil-fuel companies know their product is damaging the planet. There may also be some cognitive dissonance. Aside from sociopathic and psychopathic individuals, most people don’t want to believe they’re doing something fundamentally wrong or evil: they may want to believe those individuals who claim that it’s not going to be as bad as the scientists are saying. In other cases it’s almost ideological, it’s no longer a matter of logically looking at the scientific evidence, they see (opposition to) climate change as just another part of their cultural and ideological identity, like their stance on gun control or healthcare. In the US, belief in climate change is about as good a predictor of party affiliation as anything in this country…part of the explanation is changes in our (US) media environment; it’s now possible to isolate yourself in a bubble of self-reinforcing sources of disinformation. A study found that people who habitually watch Fox News are actually less informed. The article title was Watching Fox News makes you dumber! In US politics, you don’t need to win the argument, you just need to divide the public. JG: Ireland doesn’t have the US-style ideological chasm, but instead we have a media that is tremendously uninterested and uninformed. Our leading climate scientist, Prof John Sweeney had to actually boycott a recent TV programme, on the grounds that this type of ‘debate’ (giving oxygen to known climate deniers) is feeding the problem – you’ve experienced this? MM: Sometimes, if you don’t participate, the fear is that people are only going to hear from the voices of disinformation but if we allow that sort of ‘false balance’ approach, it does a disservice to the public. If you as a scientist share the stage with an industry-funded denier, you are implicitly telling the audience that these are two equally credible voices – and they’re not. I’m sympathetic to the view that John Sweeney expressed about the fallacy of false balance. It’s like an astronomer getting into a debate with the president of the Flat Earth Society over the latest stellar observations. JG: Conventional scientists tend to ‘stay out of the fight’ and can be critical of those who do engage. What shaped your decision to get into the fight? MM: As a young scientist at the University of Virginia, I very much shared the viewpoint described, that somehow we scientists have to preserve our