The documentary was called The Great Global Warming Swindle, and it caused just as much of a storm as Channel 4 intended, though probably not quite in the way its editors had hoped. Shown in March last year, the programme had a central thesis that made it the subject of controversy long before it was shown. This was that the increase in global temperatures observed in recent decades was not caused primarily by the burning of fossil fuels and the resulting greenhouse gas emissions, but by other, less controllable, factors.
In so arguing, the film cast doubt on what might be called – though you might detect a prejudgement here – the whole global-warming industry. For if the rise in global temperatures is not mainly a consequence of burning fossil fuels, then there is little point in anyone trying to cut such emissions, either nationally or globally. The Americans can continue running their gas-guzzlers; the Chinese and Indians can cheerfully carry on building power stations, and we British can go back to our slovenly habit of leaving the lights on. The only price any of us will pay for such profligacy will be financial, as scarcity and speculation drive the prices higher. We will not be condemning the planet to drought or famine, still less to premature extinction.
Predictably, given the intellectual capital invested in the view that global warming is largely man-made, the documentary drew complaints – not just from climate-change prophets indignant that Channel 4 was spreading what they saw as false information, but from eminent individuals and groups who felt misled about the programme's purpose. One of these was the Government's former chief scientific adviser, Sir David King.
Now, the media regulator, Ofcom, has handed down its long-awaited judgment. It upheld Sir David's contention that his views were misrepresented and that he was not given the chance to reply. It also upheld a complaint by Carl Wunsch, an oceanographer from the Massachusetts Institute of Technology, who said he had been led to believe that the programme would discuss the "complicated elements" of climate change "in a balanced way", whereas the result – he argued – had been "an out and out propaganda piece".
Ofcom also ruled that Channel 4 had breached its commitment under the Broadcasting Code to show "due impartiality" on matters relating to public policy. It did not, however, find the audience had been "misled so as to cause harm or offence".
Well, I suppose we can be thankful for small mercies. The reason for that negative finding, though, implicitly supported the very argument the documentary sought to contest. It reasoned that no harm had been caused because the link between humans and global warming had already been "settled" well before the documentary was aired. In other words, Ofcom regarded the prevailing consensus as so strong that there was no need to worry about a little one-off television programme that set out to say something different.
But is this the sort of judgement the media regulator should be required to make? The very prevalence of the global-warming consensus was surely a good reason, as Channel 4 argued in its defence, for giving at least some air time to another view.
The regulator's requirement that broadcasters be impartial on controversial issues of public policy, not just across the network, but within the same programme, also seems misguided. Of course, we have strict rules on political impartiality during election campaigns, and quite right too. And, of course, public broadcasters have a duty to use their considerable power responsibly. But should a documentary really be censured for presenting a particular point of view? Why can balance not be assessed across a broadcaster's output? And if, as with global warming, the argument is considered "settled", but a few qualified people still stubbornly – heroically? – demur, is the minority view then to be effectively silenced?
Mankind's culpability for global warming – which, it seems, is now being taught as gospel from primary school through to university – is only the most conspicuous example of an intellectual consensus that has been elevated into orthodoxy, to the point where doubters are routinely dismissed as fantasists or fools. Bjorn Lomborg, the Danish environmental scientist – yes, scientist – who infamously argues that there are better ways to help humanity than trying to stop global warming, is pilloried in mainstream climate-change circles as akin to a diabolical force.
The embrace of consensus has a particularly malign influence in science, where dissenters from a whole collection of current orthodoxies find themselves frozen out of the research funds and publications necessary to pursuing their career. The fetish with stem cells as a cure-all, for instance, has had scientists rushing to this area of research, because this is where the money is.
But the same tendency can be observed in any field where there is a body of information that either requires special expertise or is restricted to a closed circle. I have given up counting the number of conferences – in disparate fields, including the humanities – that are promoted as linked, perhaps tangentially, to climate change. Quite simply this is how academics attract funds. You don't dissent if you want to get on.
My own original field, Russian studies, has been riddled with orthodoxies down the years. Time was when those British academics toughest on the Soviet authorities – eminent and committed scholars , such as Leonard Shapiro, had to leave the country to gain a professorship. In recent years, the image of post-Soviet Russia speeding back to dictatorship has been almost unchallengeable in political and intellectual circles, even though the same evidence could be interpreted in quite a different way.
And we hardly need to talk about the intelligence world. How was it that the leaders of US and Britain convinced themselves that Iraq was bristling with weapons of mass destruction? What happened to those - few - insiders who hazarded that perhaps it was not so? Who discredited Scott Ritter and his fellow doubters in the UN weapons inspectorate? In so specialised and closed a field, a challenge can all too easily be labelled treachery.
US agencies – and perhaps by now our own MI5/MI6 – have units set up with the specific purpose of questioning the prevailing wisdom. Perhaps there should be equivalents elsewhere – in science, in academia, anywhere where an overwhelming consensus threatens to close down discussion? And why not a new broadcasting code that enshrines a similar provision? In the meantime, perhaps Channel 4 would do the natural sceptics among us a favour by repeating The Great Global Warming Swindle, with all the complainants lined up for an immediate right of reply. So we can reach our own conclusion.