Is Pascal's wager appropriate?

The problem with Pascal's wager is that its set up is for a binary probability ie an either or situation. But there is a bias in the way this one has been set in that it is a choice between nothing and a single choice on climate change which is to reduce pollution or carbon emissions.

But another choice is to take actions to mitigate the impacts of climate change such as developing foods that can grow in elevated temperatures and other coping mechanisms. Pascal's wager then can't determine which of two strategies should be pursued.

I have to admit to being in the sceptic camp. My main problem is the news that is emerging that the rates of loss of ice exceed the models. This means that the models are misspecified in some way or miscalibrated. In the first instance it may mean that carbon emissions are not the only thing driving this and if that contention is correct then we may be putting all our eggs in one basket if we adopt a politically correct approach of dismissing sceptics outright and just focus on carbon emissions instead of refining our understanding. Ironically Pascal's wager really is about not committing to a belief, but relying on probability.

A much stronger argument is that there are other benefits to reducing pollution that are unrelated to climate change and that the first steps on this road are relatively cheap to pursue. I wouldn't be an economist if I didn't want us to look at the costs and benefits and optimise for a fuller model of how the economy and the environment interact.

It's a debate where a little knowledge may be a dangerous thing and climate change populist thinking is an act of faith not of science. As such it potentially sets up similar anomolies to what we see in the genetically modified foods debate where the same people who oppose GM foods often simultaneously support stem cell research on embryos.

Is it easier to be populist than to tackle the Hard Questions>

The Great Climate Change Debate

There is no shortage of people stating with confidence that climate change is real and that, unless we act quickly and decisively, the world is headed for a disaster from which we cannot recover. On the other hand, it is not at all hard to find those who resist that view, either sceptically (claiming that the evidence is inconclusive) or categorically (claiming that there is no real evidence at all). And the interesting thing is that both sides seem to be able to find scientists who support them. So, what are we to believe and, more importantly, what are we to do?

Many people approach the argument by piling up evidence, in the form of scientific articles, or even to quote statistics in the form of the numbers of articles or scientists on each side, as if the matter could be decided simply by taking a vote. Of course the qualifications and reputation of each writer or speaker presenting evidence, and drawing conclusions from that evidence, are crucial to deciding how much attention we should pay. But even that is hard to determine. Usually all we have to go by is that person’s “celebrity status” (think David Suzuki, Al Gore or Tim Flannery). Furthermore, in many cases our position is largely determined before we examine any evidence or arguments, based on broader political and ideological beliefs.

So, perhaps the solution is for all of us to take university courses in climatology and then reserve our judgements until we reach at least doctoral level and are able to examine – and understand – the evidence on our own. Alternatively, we could use basic critical reasoning skills, combined with whatever information and understanding is available to us now.

Firstly, we need to state the issue clearly and precisely. The question is not “Is climate change real?” Rather, “Is human activity making a noticeable, and detrimental, effect on the earth’s climate?” If the climate were indeed changing but it turned out that it was part of a the same natural cycle that caused the last ice age, then, while it would be unfortunate, there would be no need to drastically change our behaviour with respect to carbon emissions.

Pascal’s wager
The 18th century French philosopher, Blaise Pascal, made an interesting contribution to the philosophical debate of the time about the existence of God. He looked, not at the evidence, but the consequences of believing, or not believing. Pascal presented four possibilities, based on whether or not God existed and whether or not one believed. If God existed and you didn’t believe in Him, then you would be punished with eternal damnation. If God existed and you did believe, then you would be rewarded with eternal life in heaven. If you believed in “God” but it turned out that no such being existed, your piety would have been “wasted”, but on the other hand, there would be neither reward nor damnation after death. Finally, if you were an atheist and it turned out you were right (i.e. there was no God), you would have simply lived your life for yourself and death would be final, as expected.

So, in a similar vein, let us assume for the sake of the argument, that support for both sides of the debate are equal, that there is a 50% chance that human activity does (or does not) cause climate change. That gives us the following four possibilities:

Action	A. If human activity causes climate change	B. If human activity doesn't cause climate change
1. Do nothing	Global disaster	No change
2. Do something (reduce CO2 emissions, etc.)	(Hopefully) disaster averted, or reduced	Pollution reduced Some unnecessary spending Some unnecessary fear

Thus, even if climatologists were more or less equally divided in their opinions, even if the evidence were truly inconclusive (not just the normal , scientific less-than-100% certainty), the relative consequences would be massively unequal. The two negatives, indicated in cells A1 and B2 above, are: nothing less than catastrophic on the one hand, and uncomfortable and inconvenient on the other.

I think the choice is clear.

The next three meetings (until 6 April)

• Mon 23 February. Topic: The significance of the wedding at Cana, in particular the role of Mary
• Mon 16 March
• Mon 6 April. Passover meal