Climate change denial is on the rise, encouraged no doubt by the example of that great intellectual President Donald Trump.  That other intellectual giant Andrew Bolt had a crack at me recently for what I thought was the modest suggestion that we need to listen to what the scientists are telling us.  Good on Bolt for his ability to take cheap shots from behind the shelter of the Murdoch press.  But still, it was a cheap shot on an issue which deserves more serious attention.  Trump may not have the intellectual rigour to think about these things, but Bolt might.

What drives people to question climate science is the desire to profit from exploiting coal resources.  But what climate change sceptics like Trump and Bolt ignore is the precautionary principle.

If global warming is real, it threatens everyone.  It raises questions about the viability of the human species on Earth.  In simpler times, the worst consequences of global warming would threaten only a portion of mankind.  However, the growing interdependence of all people means that a catastrophe in Western agriculture or in Chinese manufacturing or in the major trading cities will have consequences for practically every human being.

The solution to global warming is, primarily, a question of science.  However, history shows us that scientific solutions are generally compromised by politics.  Politicians in most nations are answerable to their people.  Without careful leadership, the people of most nations will prefer their own interests ahead of others’ interests.  This is true locally and globally.  The refusal of Australia and the USA to ratify the Kyoto Protocol was a regrettable example: it was a triumph of selfish, insular concerns over the dictates of science and the interests of the entire world.

The debate about global warming is a useful illustration of the way politics and self-interest can damage public discourse.  The  5th report of the IPCC is clear: global warming is real, dangerous, and to a significant degree the result of human activity.  These findings are accepted as true by about 97% of the world’s scientists.

Some groups have a vested interest in slowing or stopping action to combat climate change.  Big oil and the coal industry are obvious examples.  They have a lot to lose, and delaying action on climate change serves their interests.  The debate, unfortunately, has tended to focus on sniping at specific facts identified by the IPCC.  And some people, quite correctly, argue that science is not decided by democratic majority.

Morgan polls indicated that in 2008 about 35% of Australians nominated the environment as a major issue: by 2013 this had fallen to 7%.  The debate shifted from acceptance to doubt to indifference.  What is staggering about the shift is that it ignores the seriousness of the problem itself.

If climate scientists are right, we have less than 5 years in which to act on climate change.  Even Tony Abbott eventually acknowledged that climate change is real and (at least in part) anthropogenic.  Even so, it must be noted that his chief business advisor, Maurice Newman, denied climate change as did some members of Abbott’s cabinet.

Turnbull seems to have thrown his hat in the ring with the fossil fuel industry, so if he has any concerns about climate change, he has subordinated them to his political survival.

If climate scientists are wrong and, of course, they might be wrong, then we will spend a lot of money for no advantage.  But if they are right…

Suppose there is an 80% chance that all the scientists are wrong (that is, only a 20% chance they are right).  If we do nothing about climate change there is only a 20% chance of an avoidable catastrophic outcome.

But that is worse odds than Russian roulette.  In Russian roulette, a revolver with 6 chambers has just one bullet in it.  When you hold the revolver to your head and pull the trigger, you have a one chance in six of a bad outcome.  One in six is more favourable odds than on in five

It may be objected that, in Russian roulette, you hold the gun to your head, and if the one in six chance goes against your child, then the child dies.  If climate science is right, we won’t all die.  OK, so try playing Russian roulette with your children, but hold the gun to their stomach: if the one in six chance goes against your child, it’s not fatal, just dangerous and very painful.

Other arguments which support taking action just in case include: if you were told that 97% of engineers predicted that the bridge will collapse, will you walk across it?  If the airline tells you there is a 97% chance that the plane will crash, will you nevertheless get on board?

Those who would withhold action on climate change (by denying it, or by extending the argument about the steps that should be taken, thereby delaying any action at all) are playing Russian roulette with our children’s future.  But those who doubt will ultimately fall back on the idea that it is people in other countries who will bear the brunt of climate change.  This idea is rarely articulated, because it is self-evidently unrespectable to say that other people’s suffering is less important than our own.  But if anyone makes the argument, they are not only immoral, they are also wildly optimistic.