Widdows' Wager on Global Warming

Many are familiar with Pascal's Wager, an argument for believing in God on pragmatic grounds that goes roughly as follows:

Let us weigh up the gain and the loss involved in calling heads that God exists. Let us assess the two cases: if you win you win everything, if you lose you lose nothing. Do not hesitate then; wager that he exists.

For one reason and another, I'm not very convinced by Pascal's Wager, but it is justifiably famous, and it makes a good template for what, for want of a better name, I'm going to call Widdows' Wager:

Let us weigh up the gain and the loss involved in calling heads that climate change caused by human activity is not a problem. Let us assess the two cases: if you win, you get to enjoy a somewhat higher consumerist lifestyle for the next century or two until fossil fuels run out and we have to think of something else; if you lose, you might cause incalculably great damage for an incalculably long time. Do not hesitate then; wager that it is a problem.

This is a very simple point but it seems to be largely missed in the whole debate at the moment which seems to be focussed on trying to prove or disprove that global warming is happening. This is like trying to sell someone car insurance by proving to them that they are going to have a crash tomorrow, or alternatively, like refusing to buy car insurance because nobody can prove this to you. So what? So you might well get away with driving for a day without incident, and then what do you do? Crow delightedly that the person trying to get you to buy insurance was an idiot?

My three year old daughter, in the past 6 months, has thoroughly grasped the concepts of risk and danger: that you know that something is dangerous, that it might hurt, and therefore you avoid risking it unless you have a very good argument why taking the risk is necessary. What is it that my three year old understands that the global-warming-do-nothings fail to grasp? Or are global-warming-skeptics too smart for seatbelts?


The Wikipedia articles on Pascal's Wager contains extensive quotes from number 233 of Pascal's Pensées, in which the wager is stated.

The argument presented here is sometimes known as the Precautionary Principle.

It has been cogently presented in much greater detail in video form as well, see http://www.youtube.com/watch?v=zORv8wwiadQ.

Dominic Widdows, January 2010. With thanks to Michael Higgins and William Cohen for comments and references.