Blaise Pascal’s ‘wager’ was a pragmatic response to arguments about religious belief: if you believed and God didn’t exist, you hadn’t lost much, save your Sunday mornings. If you didn’t believe, and God did exist, you would burn in hell. Now there are obvious differences between this and climate change; we simply don’t know if God exists or not, but there is an overwhelming body of science which suggests that climate change is real (and which doesn’t vanish at the stroke of a hacker’s keyboard). But in the face of people who continue to assert that the science is flawed or even the product of conspiracy, the wager seems a good model.
So, with two choices and two outcomes, the matrix looks like this (click to enlarge):
Climate change sceptics usually portray the costs of taking action as being excessive, and (logically from their sceptical position) having no benefit. But this isn’t right. Most of the actions taken to reduce emission also reduce energy demand, so have financial pay-offs in the short-term, and reduce the problems caused by increasingly tight energy resources over the medium term.
As a result, the pay-offs from the matrix of doing something are always better than doing nothing. Of course, as a 2×2, the matrix implies that it’s as likely that the climate science is right as it is wrong, and also that we’re as likely to do something as not to. Neither of these is true. The likelihood of the climate change science being right is at least 95%, and probably higher; the likelihood of us doing something effective is probably no more than 40%, and that’s probably optimistic, judging by the politicking about Copenhagen and elsewhere. So the chances of ending up in the top right quadrant – with the rapid warming of the planet and all the grim consequences that follow from it – is comfortably more than half.