Thursday 26 November will be the high water mark of Australian climate change denialism’s political influence. Malcolm Turnbull’s stoic courage in Parliament House on Thursday lances the boil. It will be seen in retrospect as a defining, cleansing moment for the Australian Liberal Party.

To put this in context, Al Gore’s new book Our Choice offers instructive reading. Gore robustly exposes the motives and methods of the American denialist movement. Australia is some years behind, but the political parallels are close. From the early 1990’s, major American carbon-based corporations came together in an immensely well-resourced movement, the Global Climate Coalition (GCC).

Their objectives were to protect for as long as possible the value of their huge carbon-based assets, through a systematic casting of doubt on climate science’s growing understanding of the threat to humanity of disruptive global warming.

They used well-tried methods, of the tobacco companies’ campaign against anti-smoking regulation. But this time, the stakes were much higher, and the potential to mobilise large sections of disturbed public opinion much larger. The high stakes involved, with climate science calling for major decarbonisation, and the accompanying fears of possible losses to existing industry assets and jobs, gave fertile soil for the GCC’s campaign that such change was premature or unnecessary.

Over the next 15 years, a denialist movement steadily grew in strength and boldness, especially but not only on the conservative side of politics, and in Australia as well as the US.

Scientists and political commentators alike underestimated the grassroots power of this anti-science movement to influence politicians. As the Intergovernmental Panel on Climate Change’s warnings of disruptive climate change firmed from 2003 onwards, so too did the political strength of anti-science denialism in Australia.

Its first successful use of its power was the white-anting of the Garnaut Climate Change Review. Through 2008, influential sections of Australia’s business sector, trade union movement and conservative media articulated the case for climate policy inaction with increased audacity. This was accompanied by a growing grassroots campaign, expressed though mounting website activism and direct pressure on politicians from committed deniers and doubt-sowers. Weaker politicians wilted under the onslaught.

Kevin Rudd was shocked to see in 2008 how deeply Australian mainstream industry and trade unionism thinking had been infected by denialist views. In September 2008 he abandoned Garnaut’s recommended 25% Australian emission cuts 2020 target. Rudd’s ETS became a hollow shell. His decision for 5-15% cuts by 2020 sent an encouraging message to denialists, that in his political heart he did not believe the IPCC warning of disruptive climate change if the world failed to move to serious decarbonisation.

With a weak carbon-protectionist ETS in the bag, the deniers shifted their policy focus to another remarkably ambitious goal: trying to turn the Opposition into a denialist do-nothing coalition.

And they very nearly succeeded on Thursday. Denialists in the coalition almost toppled Malcolm Turnbull. There was Shakespearean tragedy in this confrontation. An expanding gang of moral and intellectual pygmies and opportunists combined, to very nearly bring down a brave and far-sighted leader. They could no longer see how they had been misled and used by the carbon lobbies.

Turnbull is right. His short-sighted detractors are wrong. Climate change denialism must be confronted, in the Opposition as in the governing party: and as Rudd belatedly began to do in his Lowy speech. The reality of disruptive climate change directly threatens the security of our children. The need to decarbonise Australia must be confronted bravely, even if it is almost too late. There is no more important political agenda than this.

The 5% ETS, though deeply flawed, deserves passage because it will establish a policy benchmark of recognition of climate change’s existential threat to our children. The Greens ought to vote for it in the Senate, along with Labor and intelligent conservatives, as recognition of its symbolic importance as a bridge crossed.

International events and opinion are moving in Turnbull’s favour. Obama’s announcement of a 17% minimum US 2020 target with stronger targets thereafter will strengthen international resolve to achieve something meaningful in Copenhagen. Public opinion polls register renewed understanding of the priority of the climate issue, now that the worst of the GFC appears over.

The recklessness on Thursday of the over-ambitious malcontents and opportunists in the coalition will be seen in retrospect as purging the boil. It will allow Turnbull to reconstruct a loyal shadow cabinet of climate change realists, on the model of David Cameron’s UK Conservative Party.

In 2010, Australia will have a more productive political environment for serious attention to climate change mitigation and adaptation policies. Our children need responsible stewardship from our generation. Rudd and Turnbull can together take the debate forward, in a spirit of Churchillian resolve and stoicism. I salute them both. We are entering a Dunkirk moment, which demands political courage from both government and opposition parties.

It is good that the boil has been lanced in the coalition. The weaker elements ready to appease the self-interested ruthlessness of Australian carbon lobbies are now exposed by their own actions.

Tony Kevin’s latest book on Australia’s climate change crisis is ‘Crunch Time’ (Scribe, 2009). He is a former diplomat and author of ‘A Certain Maritime Incident: the sinking of SIEV X’ and ‘Walking the Camino’.