The scare
In early December 2008, The Guardian, a newspaper of the British Left and an unquestioning true-believer in the catastrophist version of climate alarm, quoted Professor Myles Allen, a physicist at Oxford University, as saying computer models such as one that he has developed can now ascribe individual extreme-weather events to anthropogenic "global warming", allowing environmental pressure groups to sue the corporations they believe are to blame for the catastrophic heating of the planet. Professor Allen joked, "We are starting to get to the point that when an adverse weather event occurs we can quantify how much more likely it was made by human activity."
He said his team had used a "new technique" of comparing two models -- one including and one excluding anthropogenic greenhouse-gas emissions -- to identify the impact of manmade "global warming" and, for instance, to work out whether "global warming" worsened the UK floods in 2007, which inundated 10,000 properties and forced the evacuation of 11,000 people from their homes. He added that people affected by floods could "potentially" use the findings to begin legal action. He said, "It's just a question of computing power. We can work out whether climate change has loaded the dice and made extreme weather more likely. And once the risk is doubled, then lawyers get interested."
The truth
Even the UN's climate panel, the Intergovernmental Panel on Climate Change, admits in its 2001 report that the climate is a "complex, non-linear, chaotic object" whose long-run evolution cannot be predicted by any method. In this the panel echoes the celebrated paper Deterministic Non-Periodic Flow, with which the mathematician Edward Lorenz founded the new mathematical discipline of chaos theory in 1963. Precisely because the climate is, in mathematical terms, a chaotic object, it is altogether impossible to predict the likelihood, timing, magnitude, duration, or even the sign of any "phase transition" - the mathematical term for a sudden, extreme event that temporarily disrupts what otherwise appears to be the steady state of the object. For this reason, it is not possible to ascribe individual extreme-weather events to "global warming", as the IPCC makes explicitly clear in both its 2001 and 2007 reports.
The UK flooding of 2007, mentioned by Professor Allen, cannot in any event or by any stretch of the imagination be ascribed to "global warming", because at the time when it occurred the planet had been cooling for almost six years, and there had been no statistically-significant net warming for 12 years. It is always possible, however, to construct a model that overemphasizes the imagined impact of increased atmospheric carbon dioxide concentration on temperature, and then to claim that without this (exaggerated) influence the extreme-weather event in question would not have occurred.
There would certainly be no prospect of anyone successfully pursuing a prosecution of alleged polluters on the basis of such attempts to pretend that the evolution of a chaotic object can be modeled with sufficient precision to determine whether an individual event was caused by "global warming". The standard of proof in criminal cases is "beyond reasonable doubt": and Lorenz has long proved beyond reasonable doubt that computer models such as those of Professor Allen cannot do what he says they can do. See also Giorgi (2005).
In civil cases, the proof is less exacting: the issue would be decided "on the balance of probabilities". Once again, however, Lorenz's paper would stand firmly in the way of a successful civil suit against alleged "polluters" said to have caused "global warming" and hence to have triggered some extreme-weather phase-transition or another. Since it is impossible "by any method" (Lorenz's words) to predict the long-run evolution of a chaotic object, and since we know that "long-run" means less than six weeks when applied to an object as complex as the climate, it is likewise impossible to evaluate the probability that a particular extreme-weather event was triggered by a particular corporation acting in a particular manner between particular dates causing a particular quantum of "global warming" - especially given the inconvenient truth that the planet has been cooling for seven years.
It can readily be demonstrated that the contribution of even the largest fossil-fuel corporation to total "global warming" (if there were any) is infinitesimal. To take an example: if one were to close down the entire UK economy, flinging the nation back into the Stone Age but without even the ability to light a fire, global greenhouse-gas emissions would fall by 2% - and only that much on the assumption that the lost production in the UK was not made up in other countries such as China, where - to make matters worse - carbon emissions per unit of (inefficient) production are close to twice those of the UK. In such circumstances, no proof even on the balance of possibilities would be possible.
Furthermore, any fossil-fuel corporation sued by environmental pressure groups (or by stooge plaintiffs funded by them) would be entitled to plead that governments had not made the emission of fossil fuels illegal and, therefore, that they were legitimately entitled to continue their emissions -- always subject to whatever pointless "carbon taxes" or "cap-'n'-trade schemes the government had introduced. Properly speaking, therefore, even if there were a potential case against any corporation as a result of Professor Allen's over-hyped claims (which there is not), it would be governments and not corporations against whom the actions would lie. And governments, just like the corporations, would be entitled to argue that a balance has to be struck between flinging their people into poverty caused by the shutdown of industries dependent upon carbon emissions for their energy and transport, on the one hand, and the (negligible) imagined risk that carbon emissions will cause catastrophic "global warming".
Slowly but surely, the number of news media willing to give credence to fantasies such as those which Professor Allen puts forward is declining as the truth dawns: carbon dioxide's impact on "global warming" is small, harmless, and largely beneficial. In practice, the international, alarmist Left has taken very great care not to get into court battles over the science behind "global warming", because the courts, unlike the majority of the news media, are obliged to give a full and fair hearing to both sides of the story. Therefore, all of the "global warming" court cases instigated by the alarmist faction have been sweetheart cases, where both sides secretly want the same outcome. The recent case by lavishly-funded environmental groups against the US Secretary of the Interior to order him to make a decision on listing polar bears as an "endangered species" was a prime example: Mr. Kempthorne was as much a true-believer as those who were apparently suing him, and the court was in effect used as a mere rubber-stamp, in which no real argument was heard.
The alarmist faction knows that, if it were to bring a case against a corporation whose executives were not minded merely to believe in the extremist presentation of "global warming" just because it is temporarily in fashion, they would lose. The case of Dimmock v. Secretaries of State for Education and for the Environment in the UK in 2007 was a very clear warning. The UK Government threw all of the resources of the taxpayer and of the Meteorological Office at the case, attempting to defend Al Gore's sci-fi comedy horror movie against the plaintiff's allegation that it was serially and seriously inaccurate. The Government failed and was humiliated. The judge, having heard both sides, said bluntly of Al Gore, and particularly of his unscientific allegation that sea level was about to rise by 20 feet, that "the Armageddon scenario that he depicts is not based on any scientific view". A few more judgments like that and the "global warming" fantasy would rapidly collapse. End of scare.