Guest essay by Douglas J. Keenan
Temperatures on Earth’s surface—i.e. where people live—are widely believed to provide evidence for global warming. Demonstrating that those temperatures actually provide evidence, though, requires doing statistical analysis.
All such statistical analyses of the temperatures that have been done so far are fatally flawed. Astoundingly, those flaws are effectively acknowledged in the IPCC Fifth Assessment Report (AR5).
The flaws imply that there is no demonstrated observational evidence that global temperatures have significantly increased (i.e. increased more than would be expected from natural climatic variation alone).
Despite this, one of the main conclusions of AR5 is that global temperatures have increased very significantly. That conclusion is based on analysis that AR5 itself acknowledges is fatally flawed. The correct conclusion is that there is no demonstrated observational evidence for global warming.
Full critique at http://www.informath.org/AR5stat.pdf
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He closes with these quotes:
The reason for so much bad science is not that talent is rare, not at all; what is rare is character. People are not honest, they don’t admit their ignorance, and that is why they write such nonsense. — Sigmund Freud
Half the harm that is done in this world is due to people who want to feel important. They don’t mean to do harm — but the harm does not interest them. Or they do not see it, or they justify it because they are absorbed in the endless struggle to think well of themselves. — T.S. Eliot
You should, in science, believe logic and arguments,carefully drawn, and not authorities.—Richard Feynman
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Mr. Keenan, read that pdf start to finish and learned a bit about assumptions that I never realized, that assumption are so tightly coupled to statistical analysis and MODELS!. Nice work.
Thank you Doug Keenan for a clear, well written article.
I was especially interested in your paper on calibrated and uncalibrated C14dates. It would be interesting to know the error ranges between the two,if, as you say, they increase in time, 40-50 thousands years back starts to look very wobbly..
I can understand your criticism of C14dating methods being unpopular, but, good on you for persistence.
It seems tree rings do have their uses !
richardscourtney:
‘s are independent values identically distributed randomly with a zero-mean distribution of known variance, the 
‘s are known coefficients, and the process is subject to boundary conditions in accordance with which the average trend over a large number of runs tends to zero.
Having in other contexts been in your current shoes, I sympathize with your frustration at being unable to bring us unwashed to enlightenment. Still, I am unable to give you the satisfaction that appearing edified would have afforded, and I doubt that any further effort on your part will result in any greater return; I fear your explanation’s level of abstraction exceeds that with which I can cope consistently.
Just to let you know that I did not dismiss your input lightly, though, I’ll describe the hurdle I am unable to surmount. Let’s say that Mr. Keenan had assumed for the sake of argument that the annual-global-average temperature series resulted from, say, a process such as the following:
where the
This (arguably arbitrary) assumption is what this untutored observer would consider a null hypothesis; from such an assumption, I am told, statisticians can compute the probability that an $n$-length series generated by such a process will, despite the process’s average-trend value of zero, exhibit a trend at least as high as that of some $n$-length data sequence of interest, such as the global-average temperature record. Although I can’t profess to understand how all that is done, I can accept that it probably can be, and I can (with reservations) accept that statisticians are wont in those circumstances to pronounce a trend significant if the thereby-computed probability is less than 0.05. Moreover, I would be open to an argument based on a higher probability that drawing inferences from the observed trend is unjustified.
But for me it’s a bridge too far to accept the proposition that repeatable probability calculations can be based reliably on so impressionistic a formulation as that “a system has not changed unless it is observed that the system has changed.” A result, no doubt, of my inability to think as abstractly as you, but, well, there it is.
Nonetheless, I thank you again for your input.
Joe Born:
I am replying to your post addressed to me at November 2, 2013 at 6:58 am.
You rightly observe that I adhere to the principles established at the Enlightenment. I don’t care if you are “unwashed” or not, but you correctly observe that I suffer “frustration” when confronted with people who reject enlightenment thought. And that brings me to the problem your post provides to me.
My problem is that I adhere to the scientific method and, therefore, I lack your ability to invent a new scientific method as and when it suites me. Indeed, I flatly refute any such invention unless it is fully justified and certainly when – as in your case – it is simply asserted for convenience.
The scientific method defines the Null Hypothesis. As I said in my post above at November 1, 2013 at 10:54 am
Enlightenment thought as expressed by the scientific method has provided great benefits, and I am not willing to claim I can supplant it with anything better. Also, I reject your unsubstantiated assertions that you can improve on it.
In the specific case of Keenan’s statistical analysis of GASTA time series, the statistical Null would be ‘no change in temperature anomally’. Either a statistical model of the data can determine a change or it cannot. And if it can determine such a change then that determination is only valid to the degree of its validly calculated statistical significance.
Importantly, if the analysis does not disconfirm that statistical null then that disconfirmation does not mean GASTA has not changed: it only means the available statistical methods to assess the evaluated time series cannot discern a change. Hence, the null hypothesis has not been overcome by the statistical analysis.
As I also said in my explanation at November 1, 2013 at 10:54 am
In the case of a change to GASTA there may be “empirical observation” which shows a change whether or not statistical analyses of the GASTA time series can determine it. And, as I agreed with Roger Andrews in my clarification to him at November 1, 2013 at 4:53 pm, I think there is such “empirical observation”.
None of this is – as you claim – a “level of abstraction”. It is all completely practical.
And that is why I am unwilling to consider your request that “Let’s say that Mr. Keenan had assumed for the sake of argument that the annual-global-average temperature series resulted from, say, a process such as the following: etc.”: that assumption is a “level of abstraction” and I am dealing with the practical issues which are expressed by the Null Hypothesis.
Which, of course, does not deny my true statement that “deciding a method which would discern a change may require a detailed statistical specification”. Any such specification is open to debate.
In conclusion, I thank you for this conversation.
Richard
Janice Moore says:
October 30, 2013 at 11:24 am
Dear Mr. Mosher – re: 10:41am — (eye roll)
It was in the FIRST instance, perhaps, a careless mistake made in your eagerness to refute Mr. Keenan… but after several other commenters clearly showed you your error, one can only conclude that you:
1. really do not understand; or
2. are impaired intellectually (perhaps, by pride) — no one unimpaired would intentionally make oneself look idiotic.
In case you would like to learn (even more, to prevent your succeeding in leading others astray), here is what Keenan said with my emphasis to point you to an accurate reading of his language:
… no demonstrated observational evidence that global temperatures have significantly increased (i.e. increased more than would be expected from natural climatic variation alone).
I hope that, one day, Mr. Mosher, you will be free of the darkness that clouds your heart and/or mind and which so obviously impedes your thinking abilities. Instead of persisting in trying to think well of yourself, you would be wiser (and happier, no doubt) if you would strive to have those who are
honest and logical think well of you.
Hopefully,
Janice
++++++++++++
Well (and thoughtfully) written. Mosher’s fly by shootings are merely a source of tiresome distraction to otherwise interesting reading here at WUWT. Kudos to you for not being as lazy as I often get. I find him tiring when I’m trying to get to the meat of the matter here.
Mario
Janice Moore:
The nuance that continues to elude you is the dichotomy between physics as a
mental construct and physics as the concrete manifestions of nature. The
instrumentality of mathematics in human comprehension is indisputable. But
nature operates majestically without any recourse to it. Only in a poetic
sense does nature speak to us through that language. First-rate physicists
have long recognized that academic theory is not enough. If reliable
empirical data contradict the theory, it is wrong.
Dr. K’s didactic list of dichotomies offers precious little such
recognition. And it virtually ignores the crucial issue of climate data
reliability. In fact, based upon misguided notions prevalent in “climate
science,” it draws the uncircumspect conclusion that there is no real
dichotomy between signal and noise.
What you fail to realize is that, throughout this thread, I was directing
attention of scientific readers not to Dr. K’s words as such, but to the
evidentiary requirements for sound science. Nowhere have I knowingly
misrepresented his views. Your contrary verbal impression is, perhaps,
understandable, but the “evidence” you present is illogical. All it shows
is Bart Verhaggens concurrence on the instrumentality of mathematics.
Your irrational attack on my personal integrity launched on such flimsy
grounds is reprehensible. You owe me, and other targets of your
self-indulgent ad hominems, an apology.
P.S. Personal identity may be paramount on Facebook, but should not be a
factor in any serious scientific discussion. FYI, it was Gravitar that
stuck my e-mail account with the odd WUWT log-in monicker. Internet
anonimity is not shameful hiding.
Joe Born:
In signal analysis there is a well-developed concept of detection threshold. But this requires some knowlege of the signal spectrum and employs advanced analysis techniques unfamiliair to most classical statisticians. The upshot is that the current climate state is far from reaching any such threshold that would indicate the presence of an AGW signal.
Richard Telford’s blog has written about this paper. See his comments below. He says the IPCC’s statistical model is “reasonable for the question being asked.” I wonder if Keenan has read the post or has anything to say about it?