Denialism. Why do we do it?

Life is certainly easier if we can persuade ourselves that our actions have no consequences. This is particularly so if we see our intentions as being noble - which, of course, they inevitably are!

The extreme of this view, taken at a national level, is the doctrine of exceptionalism which pervades the United States. If we (the US) do something, it is OK because of our inherent rightness; if you do the same thing, it is not because your motives are less good.

It goes back to the notion of belief trumping evidence, which I have written about previously. Ideology in all its forms, including religion, presupposes a validity, despite any amount of contrary evidence.

Evidence is fine only when it supports the ideology, and is regularly distorted to achieve this. The end justifying the means is the classic argument here.

Let's focus on a specific example: climate change.

The international effort to understand and, where possible, predict what is happening to Earth's climate is the most massive and complex scientific endeavour in history.

Reports on findings are published by the Intergovernmental Panel on Climate Change after painstaking review. The findings, as in all of science, are expressed as probabilities - and they give cause for the utmost alarm.

Carbon dioxide produced by our use of fossil fuels is changing our world now and for centuries to come. The media make little effort to inform us of the reports but often prefer to spread inaccurate comment.

Human civilisation has developed and prospered over a few thousand years of remarkably stable climate. That is why we are as we are. The climate is much of our context and underpins our survival as a successful species.

We do our best not to care or notice for a large number of reasons. We ask for incontrovertible proof. Science does not do that. It cannot prove that the Sun will rise tomorrow, only that the probability is very high.

If we have ideological faith in "The Market", we imagine that it will self-manage our problems. If our belief is religion, God will sort it all out for us.

Mostly, though, we just don't want to know, because we are too busy to bother - and anyway, we see ourselves as being caring and righteous. Into this mix come the experts in creating doubt.

Creating doubt is an industry in itself. The most obvious example is the tobacco industry, which insisted for years that its products didn't cause cancer, despite its own evidence to the contrary. It hired eminent scientists to support its position.

Right now the lobby groups promoting fossil fuels are doing the same thing, often with the same scientists that tobacco used. Merchants of Doubt, by science historians Oreskes and Conway, is a book that describes this process.

The last decade was the hottest on record, the previous one the second-hottest, and the one before the third-hottest. May 2013 was the 327th consecutive month that the average global temperature exceeded the average for the 20th century. The oceans store most of the extra heat and, like a heat sink, will keep our thin atmosphere warm for many centuries.

Warmer oceans cause bigger storms. Perhaps the sight of the Tasman Glacier (by far our largest) might mean more to you. Go and have a look at it, alongside a photograph from just 50 years ago.

What about public policy or the duty of government? One of the main tasks of government is to manage risks to the wellbeing of its population.

Risk evaluation is a balance of likelihood and consequence. If the consequence of something happening is very serious, then, if at all possible, that risk should be managed.

We see this all the time in earthquake and engineering standards. We understand that the consequences of lying down on a road in dark clothes on a wet night are not likely to be good, even though we might just get away with it. Certainty is not part of risk management.

It seems that the most dedicated deniers not only deny climate change but deny the risk of it. This is true hubris.

I have no problem with people challenging parts of the science - which is what scientists do all the time - but to totally dismiss risk is beyond rationality.

I often wonder what they will say to their kids and grandchildren.

Our Government, while not quite denying risk, is doing as little as possible to manage it. There is a tragic lack of leadership, which reflects badly on us as a nation.

She'll be right, too hard, leave it to the next lot, is the sort of leadership we have learned to accept.