Ask yourself the following: what would it take to make you change your mind on a strongly held belief? An empirical one, a matter of fact. Especially one which you have, in part, defined yourself by.
It’s very difficult to do. The power of confirmation bias is well known; Jonathan Haidt, in his fantastic book The Righteous Mind, says that our rational faculty acts like a press secretary, seeking support for policies that are already in place, not looking for new evidence to base policies on. We get a pleasure-chemical reward when we find evidence that supports our argument; holding controversial views, he says, is literally addictive. And now, with the advent of the internet, it is easy to find supportive evidence for almost any beliefs you may hold. Illuminati nuts, 9/11 truthers and Obama birthers, Moon landing conspiracists, Aids denialists, Young-Earth creationists; all of them can find superficially convincing evidence for their beliefs within seconds of reaching the Google home page.
And that’s just the mad stuff. On controversies like abortion, there are serious points to be made on both sides. If you want something to convince you that an 18-week foetus isn’t meaningfully human, you can find that in seconds; if you want something to convince you it is, you can find that too.
This is all in my mind at the moment because the Berkeley Earth Surface Temperature (Best) project, led by Prof Richard Muller, has published its final results. For those of you who aren’t familiar with this, Prof Muller is a professor of physics at UC Berkley, and until recently a professed “climate sceptic” (or, for the tiresome people who insist upon the full longhand version, “person who is sceptical that human behaviour is causing dangerous climate change”). He felt, looking at the findings of the Intergovernmental Panel of Climate Change, that there were serious problems with the research. So he launched a three-year study to determine whether or not the world was really warming, and whether or not that warming was man-made.
Prof Muller’s conclusion is that not only is the world warming (2.5F warmer than pre-industrial times, 1.5F warmer than 50 years ago [NB I had this in centigrade, not Farenheit, in the original version: apologies]) but that it matches perfectly to the raised levels of carbon dioxide in the atmosphere. It “appears likely that essentially all of this increase results from the human emission of greenhouse gases”, says Prof Muller.
He says they’ve addressed most of the the concerns that sceptics had about the Nasa data that the IPCC based its models on: urban heat islands, poor station quality, human bias. He addresses the mooted link to solar activity, and says that there is no statistical support for it, and that the apparent levelling of global temperature in the last decade or so is not statistically significant. He points out places where the “alarmists” have gone too far:
Hurricane Katrina cannot be attributed to global warming. The number of hurricanes hitting the United States has been going down, not up; likewise for intense tornadoes. Polar bears aren’t dying from receding ice, and the Himalayan glaciers aren’t going to melt by 2035. And it’s possible that we are currently no warmer than we were a thousand years ago, during the “Medieval Warm Period” or “Medieval Optimum,” an interval of warm conditions known from historical records and indirect evidence like tree rings. And the recent warm spell in the United States happens to be more than offset by cooling elsewhere in the world, so its link to “global” warming is weaker than tenuous.
And he says that he’s not claiming that the “science is settled”, but that the ball is now in the court of those who claim no link between human activity and global warming:
The carbon dioxide curve gives a better match than anything else we’ve tried. Its magnitude is consistent with the calculated greenhouse effect — extra warming from trapped heat radiation. These facts don’t prove causality and they shouldn’t end skepticism, but they raise the bar: to be considered seriously, an alternative explanation must match the data at least as well as carbon dioxide does.
I’m not making claims for Prof Muller’s data. I am not an atmospheric physicist and I am in no position to assess his research. What I’m interested in is the little thrill of confirmation that I get when I read his piece in the NYT, titled “The Conversion Of A Climate Sceptic” – it affirms my beliefs, so I like it. That’s how the human brain works.
Climate sceptics, on the other hand, do not like it. Last year Antony Watts of Watts Up With That said of Best that “I’m prepared to accept whatever result they produce, even if it proves my premise wrong.” He is now less convinced, publishing several posts pointing out flaws with the research, including a guest post by Willis Eschenbach saying that Best are making “their usual unsupportable claims” and calling Prof Muller’s statements “risible”. My colleague James Delingpole, meanwhile, says “the data used by Muller to draw these conclusions was unreliable to the point of utter uselessness”. They both point to other studies which suggest that recent warming in the US is at least partly an artefact of measurements. It’s an interesting look at how the same story will be picked up differently by different sides.
The trouble is, there’s no avoiding it. As a non-climate scientist, I have to accept certain things on authority, as I do with all expert knowledge. This is an argument from authority, but we all do it, and it’s vital: if I had cancer, I’d accept the authority of the oncologist and the body of knowledge of the oncology community, rather than try to guide my own treatment with information I’d found on the internet. As Ben Goldacre said long ago in a different context, you have only two options: “you can either learn to interpret data yourself and come to your own informed conclusions; or you decide who to trust”.
I’ve decided who to trust, and it’s mainstream scientific opinion: the Royal Society, the Royal Institution, Nasa, the US National Academy of Sciences, the US Geological Survey, the IPCC, the national science bodies of 30 or so other countries. And that gives me a possible route out of the confirmation-bias trap: I have, in advance, outsourced my judgment to expert bodies. If several of them changed their position, I would change mine. It’s far from perfect, but short of becoming a climate scientist myself, it’s the only option I have; otherwise my reasonable belief that the climate is changing due to human behaviour becomes an article of faith. As it is, although it is mediated through authority, it’s still, I hope, based on empirical data, on the scientific method.
What I want to ask those sceptics who, like me, are not professional climate scientists is: what’s your way out? You are as trapped by confirmation bias as I am. You will not be able to disinterestedly search through the torrents of information, false and true, on the internet and elsewhere: the more you look, the more you will confirm your own beliefs, because that’s what we do. Since the design of the human mind makes you an unreliable judge, what evidence would it take to change your mind? Who, in short, do you trust? If you look at your own beliefs, and realise that there is nothing which could shake them, then you, as much as the hard Greens, are practicing a religion, not seeking empirical fact.
Tom Chivers 