bushfire, drought, cyclone

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.

(Note: This is a copy of a post in my abandoned, but still live, blog, Some thoughts about…, from 2009. However, I believe it is as relevant as ever. Probably more so.)

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