The film denies the scientific consensus about the reality and causes of climate change, justifying this by suggesting that climatology is influenced by funding and political factors.

"[3] According to Hamish Mykura, Channel 4's head of documentaries, the film was commissioned "to present the viewpoint of the small minority of scientists who do not believe global warming is caused by anthropogenic production of carbon dioxide.

[5][6] The film's critics argued that it had misused and fabricated data, relied on out-of-date research, employed misleading arguments, and misrepresented the position of the Intergovernmental Panel on Climate Change.

Other culprits, according to the film, are Western environmentalists promoting expensive solar and wind power over cheap fossil fuels in Africa, resulting in African countries being held back from industrialising.

It argues that the consensus on climate change is the product of "a multibillion-dollar worldwide industry: created by fanatically anti-industrial environmentalists; supported by scientists peddling scare stories to chase funding; and propped up by complicit politicians and the media".

[11][1] Using a series of interviews and graphics, the film sets out to challenge the scientific consensus by focusing on what it says are inconsistencies in the evidence, and the role said to have been played by ideology and politics.

Some elements are so firmly based on well-understood principles, or for which the observational record is so clear, that most scientists would agree that they are almost surely true (adding CO2 to the atmosphere is dangerous; sea level will continue to rise, ...).

Other elements remain more uncertain, but we as scientists in our roles as informed citizens believe society should be deeply concerned about their possibility: failure of US midwestern (sic) precipitation in 100 years in a mega-drought; melting of a large part of the Greenland ice sheet, among many other examples."

Wunsch has said that he received a letter from the production company, Wag TV, threatening to sue him for defamation unless he agreed to make a public statement that he was neither misrepresented nor misled.

However it noted that the programme included his edited interview in the context of a range of scientists who denied the scientific consensus about the anthropogenic causes of global warming.

Environmentalist and political activist George Monbiot, writing for The Guardian before the programme was shown, discussed the arguments for and against the "hockey stick graph" used in An Inconvenient Truth, saying that the criticism of it has been "debunked".

He also highlighted Durkin's previous documentary Against Nature, where the Independent Television Commission found that four complainants had been "misled" and their views were "distorted by selective editing".

[38] Robin McKie, science editor of The Guardian, said the documentary opted "for dishonest rhetoric when a little effort could have produced an important contribution to a critical social problem".

He largely focused his attention on the reactions of the environmental community, first at Durkin's earlier production, Against Nature, and now at The Great Global Warming Swindle.

Lawson characterised the programme's opponents as being quick to leap to ad hominem attacks about the director's qualifications and political affiliations rather than the merits of his factual claims.

The Independent mostly disagreed with three of the programme's major claims, for example stating that "recent solar increases are too small to have produced the present warming, and have been much less important than greenhouse gases since about 1850".

[41] In a later Independent article, Steve Connor attacked the programme, saying that its makers had selectively used data that was sometimes decades old, and had introduced other serious errors of their own:[42] Mr Durkin admitted that his graphics team had extended the time axis along the bottom of the graph to the year 2000.

[45] Janet Daley, writing in The Daily Telegraph in a column headlined "The Green Lobby Must Not Stifle The Debate", noted that "Among those who attempted to prevent the film being shown at all was the Liberal Democrat spokesman on the environment, Chris Huhne, who, without having seen the programme, wrote to Channel 4 executives advising them in the gravest terms to reconsider their decision to broadcast it".

I wrote asking for Channel 4's comments on the fact—not in dispute—that the last time Mr Durkin ventured onto this territory he suffered serious complaints for sloppy journalism—upheld by the Independent Television Commission—and had to apologise.

"[47] The Daily Telegraph apologised, saying they were happy to accept that "Mr Huhne's letter was not an attempt to prevent the film being shown or suppress debate on the issue".

[48] The Christopher Booker book The Real Global Warming Disaster provides a detailed synopsis of the programme, as well as an account of the subsequent complaints and Ofcom verdict.

In response, writing in an opinion piece for the Australian Financial Review, John Quiggin criticised the programme for putting forward "conspiracy theories".

[56] In a critical review of the documentary, Barry Brook stated[57] "Amongst the selected contrarian 'experts' Durkin has rallied to his cause, there are Tim Ball and Patrick Michaels (who also happen to deny that CFCs cause damage to the ozone layer), and Fred Singer and Richard Lindzen (who, in earlier incarnations, had been active denialists of the link between passive smoking and lung cancer, despite neither having any medical expertise)."

Commenting at a Cannes film festival press conference on 17 April 2007, Durkin noted: "My name is absolute mud on the Internet; it's really vicious," adding "There is no good scientific basis for it but the theory continues to hold sway because so many people have built their careers and reputations on it.

[65] Durkin later apologised for his language, saying that he had sent the e-mails when tired and had just finished making the programme, and that he was "eager to have all the science properly debated with scientists qualified in the right areas".

Ofcom also backed complaints by Sir David King, stating that his views were misrepresented, and Carl Wunsch, on the points that he had been misled as to its intent, and that the impression had been given that he agreed with the programme's position on climate change.

However, the regulator said that because "the link between human activity and global warming... became settled before March 2007", in parts 1–4 the audience was not "materially misled so as to cause harm or offence".

In the fifth segment of the programme concerning the political controversy and public policy, however, Ofcom ruled that the programme-makers were "required to include an appropriate wide range of the significant views" but "failed to do this.

For example, the reference to Margaret Thatcher was replaced by the claim that Helmut Schmidt promoted climate change to justify the construction of nuclear power plants in Germany.

A version of The Great Global Warming Swindle (edited by Durkin to remove errors) was broadcast in New Zealand on Prime TV, 8:40 pm, 1 June 2008.