The drafting of reports by the world's pre-eminent group of climate scientists is an odd process. For months scientists contributing to the Intergovernmental Panel on Climate Change (IPCC) tussle over the evidence. Nothing gets published unless it achieves consensus. This means that the panel's reports are conservative -- even timid. It also means that they are as trustworthy as a scientific document can be.
Then, when all is settled among the scientists, the politicians sweep in and seek to excise from the summaries anything that threatens their interests.
The scientists fight back, but they always have to make concessions. The report released last Friday for example, was shorn of the warning that "North America is expected to experience locally severe economic damage, plus substantial ecosystem, social and cultural disruption from climate change related events."
This is the opposite of the story endlessly repeated in the rightwing press: that the IPCC, in collusion with governments, is conspiring to exaggerate the science. No one explains why governments should seek to amplify their own failures.
In the wacky world of the climate conspiracists no explanations are required. The world's most conservative scientific body has somehow been transformed into a conspiracy of screaming demagogues.
This is just one aspect of a story that is endlessly told the wrong way round. In the UK's Sunday Telegraph and the Daily Mail newspapers, in columns by Dominic Lawson, Tom Utley and Janet Daley, the allegation is repeated that climate scientists and environmentalists are trying to "shut down debate." Those who say that man-made global warming is not taking place, they claim, are being censored.
Something is missing from their accusations: valid examples.
The closest any of them have been able to get is two letters sent -- by the UK's Royal Society (of elite scientists) and by the US senators Jay Rockefeller and Olympia Snowe -- to that delicate flower ExxonMobil, asking that it cease funding lobbyists who deliberately distort climate science.
These correspondents had no power to enforce their wishes. They were merely urging Exxon to change its practices. If everyone who urges is a censor, then the comment pages of the newspapers must be closed in the name of free speech.
In a recent interview, Martin Durkin, who made UK TV's Channel 4's film The Great Global Warming Swindle, claimed he was subject to "invisible censorship." He seems to have forgotten that he had 90 minutes of prime-time television to expound his theory that climate change is a green conspiracy.
What did this censorship amount to? Complaints about one of his programs had been upheld by the UK's Independent Television Commission. It found that "the views of the four complainants, as made clear to the interviewer, had been distorted by selective editing" and that they had been "misled as to the content and purpose of the programs when they agreed to take part." This, apparently, makes him a martyr.
If you want to know what real censorship looks like, let me show you what has been happening on the other side of the fence. Scientists whose research demonstrates that climate change is taking place have been repeatedly threatened and silenced and their findings edited or suppressed.
The Union of Concerned Scientists found that 58 percent of the 279 climate scientists working at US federal agencies who responded to its survey reported that they had experienced one of the following constraints: