Havequestions - 25 January 2010 12:20 PM
By the way Spatch (and other DAGW Believers), I never asked for 90% certainty or any other “% certainty”. What i asked for is the “most persuasive evidence”. What is is? But don’t take these three words out of context. Keep them in the context of the two complete sentences above, which I hjave broken down into line itemes to facilitate clarity of the question.
Furthermore, the percentage certainty stated throughout the IPCC summaries is not a scientific uncertainty. It is not based on any numerical analysis. It is a figure of speach. K It is the consensus ‘gut feel’ of the Alarmists who attend the IPCC meetings.
HQ,
Sorry to disagree just a little. You are right it is a figure of speech. But the figure of speech really might be based upon a numerical analysis. The problem becomes, how to find a sufficiently alarmist expression, or figure of speech, to convey more than the bare figures alone would convey to the general public.
There’s an amusing email from the ‘climategate’ episode which highlights the problem. It involves Professor Schneider who, as we know, is very concerned about being effective, even if doing so compromises honesty.
In the email, Professor Schneider complains to his international colleagues about the expression ‘inconclusive’ being applied to an estimated 34% to 66% probability range.
I think the general public would understand that 34-66% averages at 50% and that the probability is similar to the probability of ‘heads or tails’ when tossing a coin.
Inconclusive seems about right to me. If I toss a coin honestly and fairly, without any practiced manipulation, I really have no idea if it will fall heads or tails.
Here are the email exchanges with commentary by John Costella 
. The emails are in red.
“August 23, 2000:
email 0967041809
In this email we get an insight into how the politics of propaganda completely overrode the rules of good scientific practice, when it came to publications on “climate science”. Steve Schneider of the Department of Biological Sciences at Stanford University in the United States complains to a number of his international colleagues:
… please get rid of the ridiculous “inconclusive” for the 34% to 66% subjective probability range. It will convey a completely different meaning to lay persons—read decision makers—since that probability range represents medium levels of confidence, not rare events. A phrase like “quite possible” is closer to popular lexicon, but “inconclusive” applies as well to very likely or very unlikely events and is undoubtedly going to be misinterpreted on the outside.
To anyone even vaguely familiar with probability and statistics, Schneider’s suggestion is unforgiveable; and it doesn’t take a Ph.D. to understand why. Forget about climate change, for the moment, and consider the simpler example of tossing a coin. If the coin is fair, and it is tossed fairly, then the likelihood of getting “heads” is 50%. Now, imagine that you had to describe how sure you are that you would get “heads” on the next toss, to your boss—or your spouse—without using any numbers. “It’s inconclusive” would accurately convey the fact that it’s just as likely that you would not get “heads” as it is that you would. “It’s quite possible”, on the other hand, conveys the impression that it’s a possibility that is quite likely; it biases the language in one direction, without faithfully conveying equal likelihood that reality could go in the exact opposite direction.
Indeed, placing any emphasis at all on a 34% to 66% confidence interval is a complete misapplication of probability and statistics. Standard scientific practice is to only consider a result to be significant if the probability of it being true is estimated to be greater than some pre-determined threshold—typically 95%, for everyday analyses, or some more stringent threshold if the ramifications of getting it wrong are more grave.
Tom Karl, Director of the National Oceanic and Atmospheric Administration’s National Climatic Data Center, compounds the comedy:
Steve, I agree with your assessement of “inconclusive”—“quite possible” is much better and we use “possible” in the United States National Assessment. Surveys have shown that the term “possible” is interpreted in this range by the public.
Despite Karl completely agreeing with his butchering of the language, Schneider is concerned that Karl’s term is still not alarmist enough. His response reminds one of Sir Humphrey in Yes, Minister:
Great Tom, I think we are converging to much clearer meanings across various cultures here. Please get the “inconclusive” out! By the way, “possible” still has some logical issues as it is true for very large or very small probabilities in principle, but if you define it clearly it is probably OK—but “quite possible” conveys medium confidence better—but then why not use “medium confidence”, as the 3 rounds of review over the guidance paper concluded after going through exactly the kinds of discussions were having now?”
(Me speaking again) Now to be fair, this is not an egregious misrepresentation of the estimated mathematical probability of 34-66%, but it does highlight the sort of thinking that is going on, the double ethical bind between being effective and being honest.
The disappearance of the glaciers in the Himalayas by 2035 is a far greater distortion, as are the recently reported non-peer-reviewed reference in the IPCC reports to CO2 emissions being responsible for an increasing severity of natural disasters such as floods and cyclones.
