No surprise to see another article critical of AGW on OLO. But I have noted a change in the approach of critics. To debunk the hypothesis, all you need do is show an aspect of the science is false, note physical changes in the world which contradict it, or show a far better correlation of the changing climate with phenomena previously not considered.

The first attempts to debunk AGW were very much along these lines, but over the years the arguments were shown to be flawed. The remnants of this approach can be found on OLO threads, where minor details are discussed ad nauseum, and the main body of evidence for AGW is left unchallenged. While new challenges to AGW may arise, the major challenges seem to have failed, and further challenges are likely to be minor and infrequent. This has led to a change in approach to “Climate change is happening and isn't it great!?” and or “The climate change and associated economic scenarios of the IPCC cannot be trusted.”*. But these approaches mount no specific challenge to the science, and instead have the political aim of swaying public opinion. I see this as a sad degradation of argument and defeatism on the part of sceptics.

Anyone doubting the ability of basic science and observation to debunk popularly held myths might consider how simply it debunked the long held attribution of cholera infection to miasma. It was the simple observation of a cholera outbreak in London in the absence of miasma that debunked the myth, and lead to the general acceptance of Dr Snow's great work carried out several years earlier.

Surely the sceptics hold science in higher regard than a tool for justifying one's prejudice?

*Panaitan might note that David Henderson doesn't directly attack Michael Mann's “Hockey Stick” graph. Instead, he implies that it is tainted. Such valour!

Fester “To debunk the hypothesis, all you need do is show an aspect of the science is false, note physical changes in the world which contradict it, or show a far better correlation of the changing climate with phenomena previously not considered.”

Surely it is better to honestly recognize a “null hypothesis” than to be lead along a path to economic ruin by scientists whose lack of ethics persuade them to falsify or exaggerate results or suggest fraudulent conclusions for want of public acclaim ( which is often accompanied by public funds)?

As for “Surely the sceptics hold science in higher regard than a tool for justifying one's prejudice?”

And I think it reasonable for Skeptics to expect scientists to hold science in a similarly high regard.

- Rather than accepting the words of scientist who treat science pure as a vehicle of self aggrandizement and funding.

"A right-wing American thinktank is offering $US10,000 ($A12,940) to scientists and economists to dispute a climate change report set to be released in Paris later today by the UN's top scientific panel." From a media report.
Hope the author of this article, and most of the respondents, are not being short-changed here.

Col, if you can prove the null hypothesis for climate change, then do so. You might note that phlogiston, miasma, spontaneous generation, and ether were not debunked on the basis of defaming their adherents. They were debunked on the basis of careful observation and elegant experiment.

So Col, you and all the other sceptics can mutter all you like about unethical and fraudulent scientists making a buck from dodgy science, but it will advance your position about as much as a drunkard might advance his position by shouting abuse from the gutter. In fact, you could have ended all the argument and abuse long ago had you presented your scientific proof of a natural cause or causes for recent climate change. So why not end this silly bickering and present your evidence?

Henderson, a very highly respected economist, was one of the authoritative groups of economists and scientists who have just released a “Dual Critique” of the science and economics of the Stern Review (see my post yesterday on Jennifer Mahorasy’s article). Stern based his work on that of the IPCC and supportive groups, ignoring contrary views and evidence, so the assessment of Stern reflects on the pro-serious-AGW camp. Some major points include that -

Climate prediction is not a mature science - the last IPCC assessment found that the level of scientific understanding of nine out of twelve identified climate forcings is “low” or “very low”. Since then, findings of some major scientific papers include that - the climate forcing of methane has been underestimated by almost half; half the warming over the twentieth century might be explained by solar changes; cosmic rays could have a large effect on climate; and the role of aerosols is more important than that of greenhouse gases. That is, the role of the usual suspect greenhouse gases for which reductions are sought may have been seriously overstated

Global average temperature statistics since 1860 show the late twentieth-century warming is similar in both amount and rate to an earlier (natural) warming between 1905 and 1940. Comparisons over longer time spans “show recent warming occurred at a similar rate, but was of lesser magnitude, than the earlier, millennial warmings associated with the Mediaeval, Roman and Minoan warm periods”.

Other plausible explanations of recent warming by professional analysts include local heating from urbanization/industrialization and longer-term geological analysis suggesting minimal impacts from greenhouse gas forcing. The science is far from settled.

Stern’s assumption that future increments of carbon dioxide will have substantially greater effects than those in the past is “contrary to all empirical and physical reasoning”. In any event, historical changes in CO2 emissions do not correspond with comparable changes in temperature and vice-versa eg the temperature increase between 1905 and 1940 occurred before greatly increased industrial emissions; and temperatures between 1940 and 1965 fell even though emissions increased rapidly.

Etc, etc. I remain in the unconvinced camp.

Fester “Col, if you can prove the null hypothesis for climate change, then do so. . . So why not end this silly bickering and present your evidence”

The point of a null hypothesis is it is just that, a “null”. A null is to test a hypothesis and declare it false, without actually proving the opposite true (something like a double negative). I suggest if you are prepared to use the term in debate you actually become familiar with its meaning.

The trail of theories which certain scientists have paraded like “trophy wives” before the public is endless and the problem, the trophies have turned out to be common whores, regardless of how they are dressed or presented. Errors and approximations abound, the hypothesis suddenly evaporating like the virtue of the village bike, when it is discovered she has been ridden around the park a few more times than any virtuous trophy would wish it to be known about.

So when someone presents a fraudulent case I am happy to declare a fraudulent case. (Just call me the boy in the crowd who saw the “Kings new clothes”).

Regardless of how “inconvenient a truth” it might be, our common future will always be better if we anticipate a future based on reasoned probabilities and doing nothing than rush ahead behind a certainty of fraud.