Right, hands up if you know what an Overton Window is. No? According to Wikipedia:
The Overton window is a concept in political theory, named after its originator, Joe Overton, former vice president of the Mackinac Center for Public Policy. It describes a “window” in the range of public reactions to ideas in public discourse, in a spectrum of all possible options on an issue. The degrees of acceptance of public ideas can be described roughly as:
Unthinkable; Radical; Acceptable; Sensible; Popular; and Policy.
Or, as RealClimate put it:
In any public discussion there are bounds which people who want to be thought of as having respectable ideas tend to stay between. This is most easily seen in health care debates. In the US, promotion of a National Health Service as in the UK or a single-payer system as in Canada is so far outside the bounds of normal health care politics, that these options are only ever brought up by ‘cranks’ (sigh). Meanwhile in the UK, discussions of health care delivery solutions outside of the NHS framework are never heard in the mainstream media. This limit on scope of the public debate has been called the Overton window.
And why should RealClimate be pondering Overton Windows? Because, they say, recent weeks have seen “a huge shift in the Overton window for climate change”:
The window does not have to remain static. Pressure groups and politicians can try and shift the bounds deliberately, or sometimes they are shifted by events. That seems to have been the case in the climate discussion. Prior to the email hack at CRU there had long been a pretty widespread avoidance of ‘global warming is a hoax’ proponents in serious discussions on the subject. The sceptics that were interviewed tended to be the slightly more sensible kind – people who did actually realise that CO2 was a greenhouse gas for instance. But the GW hoaxers were generally derided, or used as punchlines for jokes. This is not because they didn’t exist and weren’t continually making baseless accusations against scientists (they did and they were), but rather that their claims were self-evidently ridiculous and therefore not worth airing.
However, since the emails were released, and despite the fact that there is no evidence within them to support any of these claims of fraud and fabrication, the UK media has opened itself so wide to the spectrum of thought on climate that the GW hoaxers have now suddenly find themselves well within the mainstream. Nothing has changed the self-evidently ridiculousness of their arguments, but their presence at the media table has meant that the more reasonable critics seem far more centrist than they did a few months ago … [Recent stories in the NYT, the Sunday Times, the Guardian, the Daily Mail, the Daily Express and elsewhere] are based on the worst kind of oft-rebunked nonsense and they serve to make the more subtle kind of scepticism pushed by Lomborg et al seem almost erudite.
