What would change your mind about climate change?

When accused of inconsistency, John Maynard Keynes famously replied: "when the facts change I change my mind. What do you do, sir?"

Except, it isn’t that simple – as Tom Chivers explains on his Telegraph blog. All of us, he says, are subject to a psychological phenomenon called confirmation bias: 

• "We get a pleasure-chemical reward when we find evidence that supports our argument; holding controversial views… is literally addictive." 

In other words, we tend to seize upon information that supports what we already think – and thanks to the internet such material is super-abundant: 

• "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." 

So, faced with rival mountains of evidence – especially when it’s of a highly technical nature – how do you decide? The particular example that Tom Chivers has in mind is climate change: 

• "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… 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’." 

On climate change, he has decided who he trusts: 

• "…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." 

But scientific establishments sometimes change their minds, don’t they? For instance, Albert Einstein’s theory of relativity rewrote centuries of Newtonian physics. There are numerous other, if less spectacular, examples in which the mainstream view has shifted. However, that, says Tom Chivers, is precisely the point: 

• "… [it] 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." 

Yet, there is a further consideration here. If whether or not you change your mind on a scientific issue depends on the judgment of others, you need to ask whether they are capable of changing their minds. Can you, in other words, imagine them giving fair consideration to a new piece of possibly ‘inconvenient’ evidence and adjusting their conclusions accordingly? Indeed, is there any record of them having already done so to any significant extent?

If not, then you are not so much "outsourcing" your judgment as surrendering it.