I wish climate scientists would concentrate on the baleful effects of climate change instead of dishonestly cranking up their certainty that these effects will occur. It’s a discredit to anyone’s epistemic judgement to act out Pascal’s wager like that. Take the following example from today’s World at One:
BBC: “It used to be said at least that individual weather events shouldn’t be blamed on climate change, I think. You’re now able to show pretty definitively that climate change has heightened this year’s heat. Is that correct?”
Friederike Otto: “That is correct, yes. It is absolutely not true any more that you cannot attribute individual events to climate change, and especially for heatwaves. Basically, every heatwave now is hotter than it would have been without climate change. And in this particular case we found that while this heat wave is actually not a rare event any more in today’s climate, in the Mediterranean it’s about a one-in-ten-year event, so has a ten percent chance to occur in any given year, it would have been impossible to occur without human-induced climate change.”
BBC: “That is a very — as I’m sure you know, you’re a scientist — very, very strong statement: impossible. You are absolutely sure of that.”
Friederike Otto: “Yes. [There is really… this is something…] the influence of climate change on heat waves is something that we know with the same kind of certainty that we know that the earth is not flat.”
This exchange — peppered with words like ‘absolutely’, ‘impossible’, ‘absolutely sure’, ‘certainty’, ‘know’, etc. — reveals how desperately misguided scientists can be in epistemological matters. However wise or rational or morally right it may be to fight climate change, the simple fact remains that we never have certainty about theoretical matters. We can have near-certainty when making observational judgements, but non-scientists can make observational judgements with just as much confidence as scientists.
Observational judgements are claims like “look, it’s turned blue” and “the needle points to the five” which we can all make as long as our sense organs are working and we understand the language. They also include claims like “the earth is not flat” (because we have photographs and we can’t see over the horizon). And, yes, they include claims like “boy, it’s hot out there” — as long as it’s spoken of a single locality at a particular time. But claims like “the average temperature of the earth is 1.5°C hotter than it was 100 years ago” is a highly theoretical claim, not just because it depends on the calibration of measuring instruments, but because it crucially depends on the practical use of those instruments — the time of day, the proximity of built-up areas, the height above ground level, and so on — practices performed amid innumerable particular circumstances, all of which inevitably drift over the course of time. As Kuhn and many others observed, observation is theory-laden, and theories change as history unfolds.
Many climate scientists think that we are in the midst of a climate catastrophe. They see themselves as being on a moral crusade to get everyone else on board. Moral crusades are dangerous things, at least as far as truth is concerned.
But it gets worse. Let’s agree that it is wise and rational and morally right to fight climate change. When truth is given second-place to morality, courses of action — however well-intentioned — are also sent astray. By insisting that we have certainty when we don’t have certainty — and can’t have certainty — climate scientists like Friederike Otto make their own case “brittle”. That endangers the crusade itself.