Nassim Taleb, who is the originator of the Black Swan theory, is – amongst others – the author of a short essay called Climate models and precautionary measures. The basic premise seems to be that because this is a global issue,
we should ask “what would the correct policy be if we had no reliable models?”
We have only one planet. This fact radically constrains the kinds of risks that are appropriate to take at a large scale. Even a risk with a very low probability becomes unacceptable when it affects all of us – there is no reversing mistakes of that magnitude.
In a basic sense, I think this is correct. It might seem trite and cliche, but we do have only one planet. This is the only planet on which we can currently, and for the foreseeable future, survive. In fact, for all we know, the only life in the universe may exist in a thin shell around a small rocky planet, orbiting a yellow-ish star, in the outer parts of a galaxy we call the Milky Way.
Although the above quote does mention irreversibility, I think you can even make a somewhat stronger argument. It’s not only that there would be no reversing some low-probability, high-risk event, it’s that climate change itself is probably irreversible on relevant timescales. Our current understanding is that a reasonable fraction of our emissions will stay in the atmosphere for millenia. If you can’t imagine anything between catastrophe and nothing to worry about, you’re not thinking.
Also, the suggestion that we should consider what we’d do if we did not have climate models is an interesting idea. If we didn’t have climate models, we’d still have an understanding that we could change our climate by an amount comparable to the change between a glacial and an inter-glacial, and do so on a timescale considerably faster. Even without climate models we may well conclude that pushing a complex system that hard and that fast, may lead to some rather unexpected, and potentially very negative (for us), outcomes. Maybe we shouldn’t do so?
As you can probably imagine, Judith Curry doesn’t really agree with Nassim Taleb and co-authors’ conclusions, even though she likes his writing on risk. This appears to be because Judith doesn’t see climate change as a ‘ruin’ problem. If anything, she seems to suggest that AGW may be delaying a future ice age. However, this creates an interesting issue. The essay points out that
The scale of the effect must be demonstrated to be large enough to have impact. Once this is shown, and it has been, the burden of proof of absence of harm is on those who would deny it.
I think there is indeed evidence that there is a possibility of severe and negative impacts. It’s also the case that we now have options, and do have viable alternatives to fossil fuels (on that note, Kevin Anderson’s recent post is quite interesting). Hence, if people are going to claim that there is no chance of ‘ruin’, and that the solutions could do more damage to our societies than climate change itself, the onus should be on them to show this, not to simply assert it.
I’ll finish with a comment. The problem with the precautionary principle is that it’s simply a blunt tool; it essentially says that we should avoid something without specifically saying how. On the other hand, we regularly hear that we should stop arguing about the science and start discussing solutions. I agree with this and it seems, broadly at least, consistent with what this essay is saying; it’s clear that there is a risk of potentially severe impacts, therefore it’s time to accept this and to start focussing on how best to minimise the chance of these impacts materialising.