Does Moore's law now apply to human civilisation? In 1965 Gordon Moore observed that the density of transistors on integrated circuits doubles every two years or so, and predicted this would continue. Similar laws now seem to apply to every aspect of computing. And, perhaps, to the rest of the world. The information available, the scale of human interactions, the detail involved in financial deals and trading relationships and political decisions appear to be growing exponentially. We are drowning in complexity. To be good citizens we must understand what is done in our name. But how?

We lean ever more heavily on experts. But who can we now trust? Corporate PR has become so sophisticated that it's almost impossible for most people to tell the difference between genuine science and greenwash, or real grassroots campaigns and the astroturf lobbies concocted by consultants. PR companies set up institutes with impressive names which publish what purport to be scientific papers, sometimes in the font and format of genuine journals. They accuse real scientists of every charge that could be levelled at themselves: junk science, hidden funding, undisclosed interests and inflated credentials.

If journalists have any remaining function, it is to help people navigate this world: to try to understand the crushingly dull documents that most people don't have time for, to smoke out the fakes and show how to recognise the genuine article. But we mess up too. The most we can promise is to try not to make the same mistake twice.

So what can you say about a man who makes the same mistake 38 times? Who, when confronted by a mountain of evidence demonstrating that his informant is a charlatan convicted under the Trade Descriptions Act, continues to repeat his claims? Who elevates the untested claims of bloggers above peer-reviewed papers? Who sticks to his path through a blizzard of facts? What should we deduce about the Sunday Telegraph's columnist Christopher Booker?

This week Richard Wilson's book Don't Get Fooled Again is published. It contains a fascinating chapter on Booker's claims about white asbestos. Since 2002, he has published 38 articles on this topic, and every one of them is wrong. He champions the work of John Bridle, who has described himself as "the world's foremost authority on asbestos science". Bridle has claimed to possess an honorary professorship from the Russian Academy of Sciences, to be a consultant to an institute at the University of Glamorgan, the chief asbestos consultant for an asbestos centre in Lisbon, and a consultant to Vale of Glamorgan trading standards department. None of these claims is true. Neither the institute at the University of Glamorgan nor the centre in Lisbon have ever existed. His only relationship with the Glamorgan trading standards department is to have been successfully prosecuted by it for claiming a qualification he does not possess.

None of this deters Mr Booker. Armed with Bridle's claims, for the past six years he has waged a campaign against asbestos science. White asbestos cement, he maintains "poses no measurable risk to health". He contends that "not a single case" of mesothelioma - the cancer caused by exposure to asbestos - "has ever been scientifically linked with asbestos cement". A paper commissioned by the UK's Health and Safety Executive, he says, "concluded that the risk from white asbestos is 'virtually zero'".

Booker tells me he has read this paper. Oh yes? The term he quotes - "virtually zero" - does not appear in it. It does show that white asbestos (chrysotile) is less dangerous than brown or blue asbestos. But, while there is uncertainty about the numbers, it still presents a risk of mesothelioma, which depends on the level of exposure. People exposed to a high dose (between 10 and 100 fibres per millilitre per year (f/ml.yr)) have a risk (around two deaths per 100,000 for each f/ml.yr) of contracting this cancer. Only when the dose falls to less than 0.1 f/ml.yr does it become "probably insignficant". But Booker's columns contain no such caveat. He creates the impression that white asbestos is safe at all doses. The paper he misquotes also cites five scientific studies of exposure to asbestos cement, which record "high levels of mesothelioma mortality".

Two years ago, John Bridle's misleading CV and dodgy record were exposed by the BBC's You and Yours programme. So the BBC immediately became part of the conspiracy: in Booker's words "a concerted move by the powerful 'anti-asbestos lobby' to silence Bridle". He suggested that the broadcasting regulator Ofcom would clear Bridle's name. In June this year it threw out Bridle's complaint and published evidence even more damning than that contained in the programme. So has Booker changed the way he sees "Britain's leading practical asbestos expert"? Far from it. He tells me that "my view of Ofcom has plummeted": it too has joined the conspiracy.

We are not talking about trivia here. This is a matter of life and death. How many people might have been exposed to dangerous levels of asbestos dust as a result of reading and believing Booker's columns?

For several years he has been waging a similar war against "warmist alarmists", by which he means climate scientists. Nine days ago, for instance, he attacked Michael Mann for publishing a paper that shows (alongside scores of other studies) that global temperatures do indeed follow the famous hockey-stick pattern: a moderate long-term cooling trend terminating in a sudden upward bend. Mann, Booker told his readers, had been "selective ... in his new data, excluding anything which confirmed the Medieval Warming". But Mann's paper, published in the Proceedings of the National Academy of Sciences, uses every uncluttered high-resolution proxy temperature record in the public domain. How did Booker trip up so badly? By using the claims of unqualified bloggers to refute peer-reviewed studies.

Under their guidance he routinely mistakes weather for climate and makes claims about the temperature record that bear no relation to the studies he cites. My favourite Booker column is the piece he wrote in February, titled "So it appears that Arctic ice isn't vanishing after all". In September 2007, he reported, "sea ice cover had shrunk to the lowest level ever recorded. But for some reason the warmists are less keen on the latest satellite findings, reported by the US National Oceanic and Atmospheric Administration ... Its graph of northern hemisphere sea ice area, which shows the ice shrinking from 13,000 million sq km to just 4 million from the start of 2007 to October, also shows it now almost back to 13 million sq km". To reinforce this point, he helpfully republished the graph, showing that the ice had indeed expanded between September and January. The Sunday Telegraph continues to employ a man who cannot tell the difference between summer and winter.

But for the Wikipedia Professor of Gibberish, this patron saint of charlatans, even the seasons are negotiable. Booker remains right, whatever the evidence says. It is hard to think of any journalist - Melanie Phillips included - who has spread more misinformation. The world becomes even harder to navigate. You cannot trust the people who tell you whom to trust.

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