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. It also means that they are as trustworthy as a scientific document can be.

Then 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 April 6, 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. 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 UK’s leading newspapers, in columns by Dominic Lawson, Tom Utley and Janet Daley, the allegation is repeated that 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: a single valid example. 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.

Look at 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% of the 279 climate scientists working at federal agencies in the US who responded to its survey reported that they had experienced one of the following constraints: 1. Pressure to eliminate the words “climate change”, “global warming”, or other similar terms from their communications; 2. Editing of scientific reports by their superiors that “changed the meaning of scientific findings”; 3. Statements by officials at their agencies that misrepresented their findings; 4. The disappearance or unusual delay of websites, reports, or other science-based materials relating to climate; 5. New or unusual administrative requirements that impair climate-related work; 6. Situations in which scientists have actively objected to, resigned from, or removed themselves from a project because of pressure to change scientific findings. They reported 435 incidents of political interference over five years.

In 2003, the White House gutted the climate-change section of a report by the Environmental Protection Agency. It deleted references to studies showing that global warming is caused by manmade emissions. Last year NASA’s top climate scientist, James Hansen, reported that his bosses were trying to censor his lectures, papers and web postings.

At hearings in the US Congress three weeks ago, Philip Cooney, a former White House aide who had previously worked at the American Petroleum Institute, admitted he had made hundreds of changes to government reports about climate change on behalf of the Bush administration.

The guardians of free speech in Britain aren’t above the suppression, either.

I have now received several letters from the climate sceptic Viscount Monckton, who wrote to Senators Rockefeller and Snowe, threatening us with libel proceedings after I challenged his claims about climate science. After Martin Durkin’s film was broadcast, one of the scientists it featured, Professor Carl Wunsch, complained that his views on climate change had been misrepresented. He says he has received a legal letter from Durkin’s production company, Wag TV, threatening to sue him for defamation unless he agrees to make a public statement that he was neither misrepresented nor misled.

Would it be terribly impolite to suggest that when such people complain of censorship, a certain amount of projection is taking place? — The Guardian