Dan Gardner is the New York Times best-selling author of Risk, Future Babble, Superforecasting (co-authored with Philip E. Tetlock), and How Big Things Get Done (co-authored with Bent Flyvbjerg). His books have been published in 26 countries and 20 languages. Prior to becoming an author, Gardner was an award-winning investigative journalist. More >

On Skepticism and Climate Science

So you follow the news, maybe not as closely as you'd like, but you try to stay informed about major issues. And the latest buzz on climate change is unmistakable. The science is breaking up. There is no consensus. Climatologists were caught cooking the books. Forecasts of dire consequences have been exposed as nonsense. It seems that so much of what we heard over the past decade was hype and hysteria. Climate change is starting to smell like the next Y2K. Is that true? The people who are best informed about the state of climate science are climate scientists, and, as luck would have it, the joint annual congress of the Canadian Geophysical Union and the Canadian Meteorological and Oceanographic Society was held in Ottawa this week. So I attended a reception with hundreds of leading scientists and asked whoever I bumped into how they saw things. What I heard is easy to sum up. No, they said, the theory of anthropogenic climate change is not getting shakier. It is getting stronger. And no, orthodox scientists -- in contrast to many environmental activists -- did not hype the threat. If anything, they underestimated the pace and extent of change observed so far. Everyone I spoke to agreed that some legitimate scientists do not accept that human activity is warming the planet, but several guesstimated that at least nine out of 10 scientists in that room accepted that man-made climate change is all too real. So it's not unanimous. But it is a consensus. And that's significant because, contrary to those who seem to think scientific claims become scientific facts when the immaculate hands of God chisel them into marble, there is no Higher Authority that settles things. There are only scientists arguing among themselves, and when most scientists decide there is enough evidence to consider a theory to be true, it is. That's how science works. There's nothing more to it. Admittedly, casual conversation at a cocktail party is not a rigorous methodology for determining the state of scientific opinion. But I am confident that what I heard that night reflects what scientists think for the simple reason that it is pretty much what the research arm of the United States National Academy of Sciences -- the most prestigious scientific institution in the world -- said in a report issued just two weeks ago. And what every major national science academy said in joint statements issued in 2005, 2008, and 2009. I find this expert opinion impressive and persuasive because, as the reader may be aware, I am not a climate scientist. Indeed, when I try to read scientific papers discussing, say, "absorption coefficients for O2 in the Schumann-Runge continuum," my head hurts. As Socrates said, the admission of ignorance is the beginning of wisdom, and I admit I do not have anywhere near the knowledge and training necessary to make sense of the vast scientific literature on climate. I respect and rely on those who do. Similarly, I would not attempt to determine what causes cancer, whether I have it, and how it should be treated. I would ask the appropriate scientific specialists and, if they collectively agreed something is true, I would consider it true. It may not be. Scientists sometimes turn out to be wrong, even when most of them agree, but we fallible humans have no better way of determining truth. Only a fool would play amateur oncologist. But plenty of fools play amateur climatologist. They send me e-mails every time I write a column about climate change. After assuring me that they know what they are talking about because they studied science in undergrad, or they have a master's degree in engineering, they insist that, if I would read the attached three-page presentation, I would realize that the theory of anthropogenic climate change is complete nonsense. The atmosphere isn't warming. Or if it is, it's sun spots that are responsible. Or the ozone hole. Or Al Gore. I occasionally respond to these people by saying I am unqualified to conduct an independent assessment of the science and so I rely on the views of those who are, a category which does not include my correspondent. This has been known to induce conniption fits. One man furiously denounced me for having an opinion on the subject that is not based on my own reading of the evidence; I chastised him for allowing oncologists to determine if he has cancer. He did not respond. These people define themselves as brave, critical thinkers. Skeptics, in others words. But, as Michael Shermer, a true skeptic, pointed out recently in the New Scientist, they are nothing of the kind. They are dogmatists who scan scientific papers they do not fully understand for factoids that support their firmly held beliefs. They accumulate these factoids like starlings building a nest. Naturally, the dogmatists' beliefs are threatened by the fact most serious scientists support the theory of climate change, and so they deny this fact. Or they insist scientists think the way they do because they ignore contrary evidence, don't consider alternative hypotheses, and shut out critics. Some insist scientists are pushing a hidden agenda and even major scientific institutions like the NAS are fellow-travellers of Gore and the environmentalists; one man accused me of dishonestly failing to tell readers the president of the NAS is a climatologist, which apparently demolishes the NAS's credibility on climate science for reasons I cannot seem to fathom. But, as fun and wacky as these folks are, I want to emphasize, again, science-based criticism of climate-change theory, as distinct from what the fun and wacky folks do, is very much in the spirit of science and should be welcomed by any scientist worth the name. And it is. Granted, a few scientists have occasionally allowed their passion for action on climate change to get the better of them, but remember the reception I attended was peppered with scientists who doubt the theory of anthropogenic climate change. Their far-more-numerous colleagues did not throw buns, shout and drive them from the room. They chatted and drank wine. It was an amazing contrast with the public debate, which tends to be dominated by the loudest, most extreme, and most unyielding voices. It's Mad Malthusians versus Crazed Cornucopians. Either climate change is the end of the world or it's a total fraud: Whose side are you on? Reality is a bit more complicated than that. Which is why I will continue to respect and rely on scientists.