Thursday, December 20, 2012

How To Lie With Statistics – Climate Edition

Willis Eschenbach - Keep doing that and you’ll go blind:
… So it is absolutely unsurprising, and totally lacking in statistical significance, that in a comparison with 28 variables, someone would find that temperature is correlated with one of them at a p-value of 0.05. In fact, it is more likely than not that they would find one with a p-value equal to 0.05.

They thought they found something rare, something to beat skeptics over the head with, but it happens three times out of four. That’s what I found so funny. …

[Update] And of course William M. Briggs has written something on the statistical quality of that paper as well.

Wednesday, November 14, 2012

Bad Joke

Steve on the latest about the climate policy of the BBC:

Several years ago, the BBC stated in a report:
The BBC has held a high-level seminar with some of the best scientific experts, and has come to the view that the weight of evidence no longer justifies equal space being given to the opponents of the consensus [on anthropogenic climate change].
Tony Newbery (see Harmless Sky blog) was curious as to the identity of these “scientific experts”, and filed a Freedom of Information Act request. Rather than simply complying with the request, the BBC refused the request. Tony appealed to the ICO and lost. The ICO agreed that the BBC was a “public authority” but held that the information was held “for journalistic purposes” and exempt
[…]

Tony appealed to the Information Tribunal. The BBC appeared with six lawyers. BBC official Helen Boaden argued that the meetings had been held under Chatham House rules and that the identity of the participants was therefore secret. Tony was again given short shrift, with the members of the Tribunal being surprisingly partisan, as reported by Orlowski.

Out of left field, Maurizio located the information on the Wayback machine here. Rather than the participants being the “best scientific experts” as claimed, they were almost entirely NGO activists. …
The best of the best of the best, sir.

Tuesday, October 30, 2012

Bloody Bastards – The Full Story

No way Steve McIntyre would leave that without proper comment:
Karoly and Gergis vs Journal of Climate
– Steve McIntyre, climateaudit.org


On June 10, a few days after the Gergis-Karoly-Neukom error had been identified, I speculated that they would try to re-submit the same results, glossing over the fact that they had changed the methodology from that described in the accepted article. My cynical prediction was that a community unoffended by Gleick or upside-down Mann would not cavil at such conduct.

The emails show that Karoly and Gergis did precisely as predicted, but Journal of Climate editors Chiang and Broccoli didn’t bite. Most surprising perhaps was that Karoly’s initial reaction was agreement with the Climate Audit criticism of ex post correlation screening. However, when Karoly realized that the reconstruction fell apart using the methodology of the accepted article, he was very quick to propose that they abandon the stated methodology and gloss over the changes. In today’s post, I’ll walk through the chronology.

Non-Barking Dogs

Lucia's The Blackboard has an guest post by "Paul_K" on "Pinatubo Climate Sensitivity and Two Dogs that didn’t bark in the night":

Summary of Conclusions

Allowing for uncertainties in the temperature and flux datasets, the response from Pinatubo is compatible with a 2xCO2 climate sensitivity of between 0.9 and 1.7oC, with a ML value around 1.4 oC. Outside this range from 0.9 to 1.7oC, it is not possible to obtain simultaneous matches to temperature and energy balance data within a temperature excursion range of 0.5 to 0.7oC. (Note that the actual measured temperature excursion was somewhere between 0.4 and 0.5 deg C. My allowed range here already incorporates maximum correction for ENSO. For comparison, Soden’s estimate for ENSO corrected temperature excursion reaches a maximum of 0.65oC. A reduction in the allowed temperature excursion would reduce the upper bound on my estimated range of climate sensitivity.)

The DK2005 estimate is unequivocally too low because of underestimation of ocean heat transfer and a deficient model.

The Wigley2006 central estimate of 3.03oC is impossibly high because of overestimation of ocean heat transfer; it can only match temperature data if the flux information is ignored.

I suspect cynically that these results explain why quantification of the sensitivity is notably absent from the Soden2002 paper, and the flux data are notably absent from Wigley2005.

Doomsday Cults

Wikipedia: Psychological impact of failed predictions

Social scientists have found that while some group members will leave after the date for a doomsday prediction by the leader has passed uneventfully, others actually feel their belief and commitment to the group strengthened. Often when a group's doomsday prophesies or predictions fail to come true, the group leader will simply set a new date for impending doom, or predict a different type of catastrophe on a different date. Niederhoffer and Kenner attribute this motivation of the charismatic leader to maintain a consistent belief structure as due to a desire to save sunk cost: "When you have gone far out on a limb and so many people have followed you, and there is much "sunk cost," as economists would say, it is difficult to admit you have been wrong."
And:
Wikipedia on: When Prophecy Fails

Premise of study
Festinger and his colleagues saw this as a case that would lead to the arousal of dissonance when the prophecy failed. Altering the belief would be difficult, as Keech and her group were committed at considerable expense to maintain it. Another option would be to enlist social support for their belief. As Festinger wrote, "If more and more people can be persuaded that the system of belief is correct, then clearly it must after all be correct.

Conditions
Festinger stated that five conditions must be present if someone is to become a more fervent believer after a failure or disconfirmation:
  • A belief must be held with deep conviction and it must have some relevance to action, that is, to what the believer does or how he behaves.
  • The person holding the belief must have committed himself to it; that is, for the sake of his belief, he must have taken some important action that is difficult to undo. In general, the more important such actions are, and the more difficult they are to undo, the greater is the individual's commitment to the belief.
  • The belief must be sufficiently specific and sufficiently concerned with the real world so that events may unequivocally refute the belief.
  • Such undeniable disconfirmatory evidence must occur and must be recognized by the individual holding the belief.
  • The individual believer must have social support. It is unlikely that one isolated believer could withstand the kind of disconfirming evidence that has been specified. If, however, the believer is a member of a group of convinced persons who can support one another, the belief may be maintained and the believers may attempt to proselytize or persuade nonmembers that the belief is correct.
It seems the man-made apocalypse named "Sandy" has – considering the hype – passed rather uneventful in the US (unless of cause if you live on Cuba or some place else in the Caribbean, in which case the US Media or "Climate Progressives" do not give a fuck about your loss of life).

It'll be interesting to see whether the apocalypse will postponed – as in: "You were lucky this time, BUT THE NEXT MAN-MADE FRANKENSTORM WILL GET YOU FOR SURE!!11!!1!ONE!!ELEVEN!".

Or maybe the results of Sandy will be simply spruced up and fluffed up as much as possible.

[Update] OK, I'll admit it, I was wrong, I underestimated the initial reports from this storm. Yes, it was an unusually large storm, and yes it hit the USA hard. But a single freak storm does not make global warming, as neither does a single snow disaster make global cooling. And it was a single freak storm, because if you look at the past years and storms making land-fall in the US (yes, please look up the past huricane seasons here and here), only Katrina stands out, and only because the levies (protecting low laying lands) built by the US corps of engineers were shite and broke – with properly maintained levies, Katrina would have been forgotten now.