This week’s Intergovernmental Panel on Climate Change (IPCC) report will be compendious, cautious, thorough and as authoritative as a scientific report can be. But it will not make much difference.

In the world we used to live in, the one in which the ideal of scientific knowledge held true, the report would give a further boost to an already valiant world effort to shift rapidly away from fossil fuels. It would give hope that we could head off the catastrophes of a hot planet.

But we no longer live in that world (otherwise known as the Enlightenment), the one in which we thought of ourselves as rational creatures who gather evidence, evaluate it, then act to protect our interests.

While the IPCC must continue to tell those who are listening what the science is saying, it ought to be obvious to any careful observer that the debate over climate change is not about the science.

Of course the deniers, who are out in force attempting to spike the IPCC report before it appears, must pretend that it is about the science, because to admit that they are on an ideological crusade would undermine their own position. Yet it is the weapon they hide that is most powerful.

Those who believe that more scientific facts will win the day cleave to the “information deficit” model of classical science. This says people act irrationally because their knowledge is deficient. Yet facts are no match against deeply held values, the values embedded in personal identity.

The debate has not been about the science since the early to mid-2000s. Then, climate denial moved beyond the industry funded lobbying campaign it had been in the 1990s and became entrenched in the new right-wing populist movement. This was represented by the Tea Party in the United States, and has subsequently been taken up by elements of the Liberal Party in Australia.

In the 1990s a citizen’s views on global warming were influenced mostly by attentiveness to the science. Now one can make a good guess at an American’s opinion on global warming by identifying their views on abortion, same-sex marriage and gun-control. That global warming has been made a battleground in the wider culture war is most apparent from the political and social views of those who reject climate science outright.

In the United States, among those who dismiss climate science, 76% describe themselves as “conservative” and only 3% as “liberal” (with the rest “moderate”). They overwhelmingly oppose redistributive policies, poverty reduction programs and business regulation. They prefer to watch Fox News and listen to liberal-loathing shock jock Rush Limbaugh.

Like those whose opinions they value, climate deniers are mostly white, male and conservative — those who feel their cultural identity most threatened by the implications of climate change.

A similar division has opened up in Australia, with more conservative voters deciding they must reject climate science in order to oppose the kinds of values they see environmentalism representing. Right-wing demagogues like Andrew Bolt and Alan Jones have taken up the denialist cause as a means of prosecuting their war against progressive trends in Australian society.

The same is true here in Britain where the culture warriors of the conservative press have all felt it necessary to sacrifice their faith in science in pursuit a larger ideological struggle. Even the BBC repeatedly undermines public confidence in the IPCC by “balancing” the vast authority of climate science against the cranky views of a handful of unqualified “sceptics”.

Once the debate shifted from the realm of science to the realm of culture, facts were defeated. If the science challenges the values, the values will win. The braying donkeys of the Murdoch press understand this better than those of us who naively insist on the facts.

In fact it has been shown that, once people have made up their minds, providing evidence that contradicts their beliefs can actually entrench them further, a phenomenon we see at work with the upsurge of climate denial each time the IPCC publishes a report.

We are often preoccupied with visceral fears that are grossly exaggerated, and have to use our cognitive faculties to talk ourselves out of baseless anxieties. It’s the method of cognitive behavioural therapy.

In the case of climate change it is the other way around; we must persuade ourselves to be fearful using abstract information.

At present it seems easier to mobilise people by invoking fears of higher petrol and electricity prices due to carbon abatement policies than it is to persuade people to fear the vastly greater harms expected from climate disruption. We must use our cognitive faculties to take the evidence very seriously and talk ourselves into responding to something we cannot yet see. But isn’t that the essence of the Enlightenment?

So what will make a difference? When will science begin to count again? Perhaps we have evolved to respond only to immediate visible threats to our own safety, and so we are simply not programmed to react to abstract threats some way off into the future.

If so, the grim truth is that the world will give up its childish tendency to block its ears against the scientists’ unpleasant warnings only when we see large numbers of white-shrouded American bodies, the victims of climatic disasters.