Let me say immediately that I don't doubt that Planet Earth is on its way out. I couldn't be more gloomy about its future. I'm also not much of a fan of Clive James, in fact I was involved in an angry lunchtime argument with him on the subject of Iraq and what he called 'the triumph of Democracy' the last time I saw him, some years ago.

I am, on the other hand, constantly interested in how I can know whether what I read and hear is reliable. I couldn't for example put my hand on my heart and say that my belief that climate change is irreversible is based on anything very much more substantial than a tendency to trust in the green and the left, and the fact that I know from history and experience that human beings are inclined to do what they want to do until they use up the ability to do it. I'm certainly not equipped to verify the scientific arguments for or against climate change. I can't do the maths. In much the same way, I 'believe' in Darwinian evolutionary theory, which, although I've read a good deal on the subject, I'm only minimally able to verify for myself. Ditto the link between cigarettes and lung cancer. I read the reports and assume the science is right, but the truth is I don't really know.

In the Guardian, George Monbiot berates Clive James speaking on Radio 4 about scepticism for saying: 'the number of scientists who voice scepticism [about climate change] has lately been increasing'. Monbiot comments: 'He presented no evidence to support this statement and, as far as I can tell, none exists.'

Monbiot also presents no evidence to support his refutation. As far as he can tell, he says, James is wrong. He needs only to 'look at the quality of the evidence on either side of this media debate, and the nature of the opposing armies – climate scientists on one side, right-wing bloggers on the other'. Scientists = quality and correct, sceptics = right-wing, bloggers and wrong. Really? Just the two armies, big brains v. knuckleheads?

But it seems the real problem with Clive James is that he's old. Climate change denying in America is on the up, Monbiot tells us, and the majority of climate change deniers are in their sixties and older, accroding to a report from the Pew Research Centre. Monbiot agrees: it 'chimes with' his experience. It's pretty obvious, he says, that the old folk refuse to believe the truth of climate change because we have no investment in the future, we were brought up in a period of technological optimism, and we feel plain entitled to fly around the world like there's no tomorrow – well, like there will be tomorrow.

But it's even worse than just having an atrophied view of the world. Monbiot has discovered a 'fascinating corner of human psychology': people can't face thinking about death. A cultural anthropologist, Ernest Becker, in 1973 theorised that:

When people are confronted with images or words or questions that remind them of death they respond by shoring up their worldview, rejecting people and ideas that threaten it, and increasing their striving for self-esteem.

A biologist, Janis L. Dickinson, suggested that 'some people might respond to reminders of death by increasing consumption. Dickinson proposes that growing evidence of climate change might boost this tendency, as well as raising antagonism towards scientists and environmentalists.'

And so Monbiot brings us back to Clive James and the rest of us ancients:

is it fanciful to suppose that those who are closer to the end of their lives might react more strongly against reminders of death? I haven't been able to find any experiments testing this proposition, but it is surely worth investigating. And could it be that the rapid growth of climate change denial over the last two years is actually a response to the hardening of scientific evidence? If so, how the hell do we confront it?

Yes, quite fanciful. So many question marks, and even George Monbiot has failed to find any evidence for his proposition. I can't say I've ever felt more suspicious of my rather automatic readings and acceptance about climate change than after reading Monbiot's wobbly article. From one comment by one elderly commentator, we arrive, via some 'proposals', at a spurious generational argument and are asked to consider how to deal with this problem. Well, you are – I'm well past the age of reason. But bear in mind that at 46 (even accepting his assumption that I'm closer to death than he is – live every day as if it were your last, I say) George Monbiot has only got another fifteen years or so before he'll about-turning and racing in the other direction, screaming: 'There is no death, I am immortal.' Just like I do.