It’s not every day that you get to hear a serving head of state in person — even one on an “unofficial” visit. So I was pleased to be able to attend yesterday’s Alfred Deakin lecture in Melbourne, delivered by Czech president Vaclav Klaus.

Klaus had a distinguished career as an economist before turning to politics in the aftermath of the Czechoslovak “velvet revolution” in 1989. He became finance minister in the country’s first post-communist government, and later the first prime minister of the independent Czech Republic. The subsequent development of a liberal, prosperous and western-oriented Czech state is largely to his credit. After losing the 1998 and 2002 elections he was elected president by parliament in 2003 and re-elected to a second term in 2008.

In other words, Klaus is a serious figure, whose pronouncements are deserving of some respect. He is in a quite different class to, for example, mad Lord Monckton. But on the topic of climate change, his views are as uncompromising: he is a hardcore denialist, rejecting essentially the whole of the scientific position.

Like most denialists, Klaus approaches a scientific issue as if it were an ideological one. Of the six key questions that he said those who accept climate science have to deal with, five are clearly scientific ones: roughly, is climate change happening?; is it beyond the scope of prior natural variation?; is it due to carbon dioxide?’; will its consequences be catastrophic?; and can we do anything about it?

Although Klaus made the ritual denial of “I am not a climatologist”, he showed no hesitation in answering “no” to each question.

The sixth question (although actually placed fifth in his presentation) — “should climate change attract most of our attention or would other problems be a better use of our resources?” — is not solely a matter of science. There is a legitimate debate to be had here, on which an economist could have something valuable to say. But one who starts by saying “but I don’t really believe this is a problem at all” will have, understandably enough, something of a credibility gap to bridge.

Fortunately, Klaus didn’t spend the bulk of his time talking about climate change. His views on the European Union, although drawing on some of the same conspiracy-theory sensibility, were much more in his area of expertise and experience, and correspondingly more interesting.

He declared “I was right” in relation to his opposition to the euro, while admitting he would have been happy to have been proved wrong.

It’s unfortunate he wasn’t willing to attribute a similar modesty to the climate scientists, who would also be happy to be proved wrong about climate change. But to Klaus they are all deceivers of the public, only pretending to care about the environment.

To some extent, Klaus’s background explains his attitudes: spending most of one’s career under totalitarianism leads fairly naturally to a suspicion of “isms” of all sorts.

Here, without that background, claiming to support the environment but not environmentalism, women’s rights but not feminism, human rights but not “human rightism”, and so on, sounds disingenuous at best. But Klaus seemed sincere in his distrust of such social movements and his commitment to freedom and democracy.

Even so, it is unfortunate Klaus’ sponsors have promoted his most obscurantist views. Although the Deakin Lecture covered a range of topics, a subsequent function last night for the Institute of Public Affairs had him speaking on “the mass delusion of climate change”, in which all his worst impulses will have been given free rein.

We all have our eccentricities, probably more so as we get older, and the Great and Good are no exception. Once upon a time, they would have been allowed to indulge them harmlessly in private. It does Klaus’ historical reputation no good that he has been encouraged to propagate them on a worldwide stage; it would be not unlike inviting William Gladstone on a tour to talk about prostitution.

Climate change denialism risks awful consequences for the planet. One of its lesser but still tragic effects is that a man like Klaus may be remembered not as a great economist and statesman but as a crank. For that, the IPA and its fellow-travellers stand accused.