Rabett runs right over Essex and McKitrick

Eli Rabett dissects Essex and McKitrick's incompetence with averages:

Unfortunately, either Essex or McKitrick or both do not understand zero and negative numbers. You know where my money is.

Read his post to see why.

Mind you, Steve McIntyre isn't convinced that there is anything wrong with their argument because "Chris Essex is an accomplished thermodynamicist" and

my impression was that your counter-argument was mostly just belligerence. While it's possible that they made a mistake. I very much doubt whether Essex made a trivial mistake and your argument seemed to be assuming that it was trivial.

Oddly enough, Mann, Bradley and Hughes are accomplished scientists but this hasn't stopped McIntyre from arguing that they made trivial mistakes.


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I find it interesting to consider what words mean.

For example, the distinction between "arguing" and "showing". Mann, Bradley and Hughes- as a matter of fact- had a seriously defective description of their materials and methods in MBH'98. MBH themselves even say there were errors.

So given that MBH say that they made trivial mistakes, why do you try and make something out of McIntyre saying the same thing ?


I said that I "doubted" that Essex made a trivial mistake. This falls somewhat short of "dismissing" the possibility entirely. If other people can clearly demonstrate that Essex has made a trivial mistake, then so be it. I don't know much about the topic and don't have the time right now to delve into it.

As to the "accomplishments" of M,B and H, neither B nor H have any record of much mathematical or statistical accomplishment; I think that the jury is out on M. I've read Mann's work in detail and would be hard-pressed to describe this corpus as "accomplished" from a statistical point of view. In fact, I think that I've made it clear that I regard it as the opposite. Perhaps you can identify some statistical "accomplishments" that Mann can be credited with.

On the other hand, thermodynamics is a field that Essex specializes in and has published on. Having said that, I don't understand the point that Essex is making either; I don't see the big problem in calculating averages. I think it likely that Essex has considered this obvious point. The situation is a little different with Mann's PC method, which was perhaps a computer programming error. It certainly was a method that was not accurately described. The term "trivial" is being stretched here to cover some pretty different sets of facts.

If you've spotted something incorrect, then more power to you. I'm just not in a position to judge or debate the matter.

By Steve McIntyre (not verified) on 21 Nov 2005 #permalink

per, I find your post interesting, because your comments are posterable for slippery language *[Deleted. Tim]*. Your recent attempts on RPs site come immediately to mind, and your initial foray on sci.env is another one.



Aunt Polly: If Quark Soup was up you would have seen more examples. It is one sure sign that you are getting an original Dano and no some knock-off imitation. I thought of trying to get it included as a real word in standard English, but then decided that everyone knows what it means and it should keep its exclusivity.

By John Cross (not verified) on 21 Nov 2005 #permalink

well, tim
even IF McIntyre doubts that Essex made a trivial mistake in a particular argument, what does that have to do with THE FACT that MBH have made mistakes in one of their seminal papers, and that McIntyre has pointed this out ?

I think you are trying to conflate wildly different statements, and I don't understand why.

I would also understand, dear Tim, that you have a policy on name-calling on this blog. This is at least the second time that Dano has accused me of "mendacicization", a neologism which is suspiciously close to "being a liar". I am sure you would want to remedy this unfortunate situation.

As for Dano, it is fascinating to see how he engages fully with the point of debate, by simply calling names.


I tried posting this on Rabett's site, but I don't think it made it (my fault not his).

From: http://www.cgd.ucar.edu/csm/models/cpl/cpl4.0/doc9.html

Heat Capacity of air = 1.005 kJ/kg/deg K [no temperature given but I saw this other places for 20deg C)
Heat Capacity of water vapor = 1.810 kJ/kg/deg K

From my old CRC Chem Physics Handbook
vapor pressure of H2O at 5 deg C (278 deg K) = 6.543 mm Hg
vapor pressure of H2O vapor at 25 deg C (298 deg K) = 23.756 mm Hg
difference = 17.213 mm/1000mm/atm. = 1.72%.

If we assume therefore 98.28% regular air and 1.72% pure water vapor we get at 25 Deg C

.987714 + .031132 = 1.018846

This is about a 1.4% increase in the Heat capacity of saturated water from 5 to 25 deg C. For a 20 degree change in temperature therefore we get a .28 deg difference in the recorded temperature between dry and saturated air (assuming, that the cold air could hold that much water which of course it can't. and ignoring that I should probably halve the difference to assume a linear change in heat capacity) The point is that averaging the two conditions would result in different means. The difference is small, but so is the global warming amount. I think that rather than put-downs, you should try posting actual calculations with ALL the requisite differences, including the change in heat capacity for dry air at different temperatures which I didn't find in a quick look, and might be larger than the change from humidification.

Please note, I realize that typical actual examples will show less change from humidity, but I think I show you can't dismiss A&M as quite as simpleminded as you try. *Disclaimer, I haven't read their book so I might end up disagreeing with it too if I read it, but at least I wouldn't be as dismissive as you are.

By Dave Dardinger (not verified) on 21 Nov 2005 #permalink

hi per,

that's what you do. he's calling you what you are, but he's also allowed you a door through which to slip. Ah, the internet!

This is at least the second time that Dano has accused me of "mendacicization", a neologism which is suspiciously close to "being a liar". [linky added]


I am not adverse to calling someone a liar or pointing out where they are full of it.

*[Deleted, Tim]*

Viz. implying my argumentation is ad hom would work if that's all I did, but you omit the point of the comment - the second sentence.

You could, of course, take umbrage with the substance of my claim.

Or you could, per usual, hand-wave and obfuscate(1). Shall we explore the ways you use your Wurdz to obfuscate?



(1) Honoring the site of #9 above. :o)


I don't want you to come down into the mud with us, allow me to fix your link, and wash your hands of our juvenility.

per, for your perusal.

Also, this. Hopefully, Tim L. will not be angry with us for lowering the discourse, but we do it with a smile, dear per.

Cut it out guys. My [comment policy](http://scienceblogs.com/deltoid/comment/):

>There is one rule that I ask commenters to follow — please do not make personal attacks on other commenters. Such comments tend to cause discussion to degenerate into a slanging match so I will usually delete or disemvowel them. If you think some other commenter is dishonest or stupid, you should show us, by presenting evidence and letting the rest of us make up our own minds rather than telling us.

Dave, we looked at the effect of water vapor on atmospheric heat capacity a while ago, see http://scienceblogs.com/deltoid/2005/06/barton.php#comments particularly comments 208, 217, 219, 225 and 235. Do not wake that Bahner beast.

More seriously, my plaint against Essex and McKitrick has two principal points which have little to do with water vapor. First, that if you are averaging temperature and you use anything BUT a arithmetic average you HAVE to use absolute temperature especially if you are looking at radiation. Second that there REALLY are good physical reasons for using arithmetic averages.

(Your comment posted on my site, but there is a wierdness about not showing up immediately?) I'll post this there also.

Dear Dano

From Tim's comment policy:
"you should show us, by presenting evidence and letting the rest of us make up our own minds rather than telling us."
Any time you want to present evidence to back up your claims ?


Really. Your choice from #4 above, per.



I've read the messages. They don't relate directly to what I posted. And I don't care what anyone else had to say on the subject anyway.

BTW, one correction which works to my advantage. I stated I should perhaps divide the heat capacity change in half due to a linear change, but that's not right. The change in heat capacity would be essentially the same because the different heat capacities were due to the different compositions of the atmospheres rather than a change in a heat capacity due to the change in temperature. It's my bedtime now, but I'll try to work out a more real-world example in the morning and show that while the difference in temperature average is small it's not unimportant.

By Dave Dardinger (not verified) on 21 Nov 2005 #permalink

Dear Dano
as always, when asked for specifics, or evidence, I hear the sound of silence from you.

I am amused by your current line of argument. The hockey team don't have to acknowledge M&M, or supply data, 'cos they are "amateurs".

Funny thing is, McIntyre is an amateur, at least in the sense that he isn't paid for his work; but he is an expert in the statistics used in climate analysis. McKitrick is of course a professional academic.

I think the idea that if you call someone names, then you don't have to honour your obligations to them- well, it tells us a lot about Dano, doesn't it ?


Dave, the global average temperature is expressed as anomoly -- the change from the baseline average. So, yes, you might get a difference of 1.4% (though it's unlikely to be that high) in the amount of warming if you took into account the difference in specific heats between dry and moist air. Whether warming is 1 degree or 1.014 degree is not an important difference. Which is probably why they just take straight area weighted averages.

And none of this has anything to do with E&M's nonsense about harmonic means of degrees Celsius.

Steve, I didn't say that you has dismissed the argument. His error has been clearly demonstrated. You don't have to understand any physics -- it's just the mathematics of averaging -- something you claim to be an expert in. You have understood the argument and can find nothing wrong with it, but aren't going to accept it, solely on the basis that Essex could not have a made a simple mistake.

Despite your bad-mouthing of him, Mann seems to have a distinguished publication record, so it seems that by the McIntyre standard that you applied in the Essex case we should not accept your arguments against Mann.

Come on Tim, you can do better than that! The difference, whether the .5% from the earlier thread or the 1.4% in this one, is not a difference in the variance but a difference in the absolute temperature between the station temperatures being compared / averaged. Thus if we have a five degree C temperature on a mountain somewhere and a 25 degree C temperature in on the nearby seashore both of which happen to be saturated for their temperatures, we'd have a different average internal energy. Thus we'd have a different "average temperature" based on the different atmospheric compositions than we'd have in the case of a desert mountain and plain with the same thermometer temperatures but now the same compositions (since there'd be little moisture in either sample). As I promised Rabbet, I need to work out a real-world sample taking into account either the need to avoid a regime where we have to consider evaporation or getting the proper data to allow it. (I was answering a separate question on ClimateAudit a week ago or so and remember that there are some differences in the heat of vaporization of water depending on the temperature which make things rather complex.)

The trouble is that you see the maximum differences in the averages because of different compositions if you go with saturated air, but then one or the other situation will result in evaporation or condensation.

By Dave Dardinger (not verified) on 22 Nov 2005 #permalink


I am a little busy right now but I am interested and I will look over your vapor analysis at some point in the future.

However I note that this does not in any way address Eli's point about mixing up Kelvin and Celsius. This is not a trivial error.


By John Cross (not verified) on 22 Nov 2005 #permalink

Apologies, Tim.

Well, per, thanks for beginning. I expect a long string of hand-waving, and I see you've already begun.

But let me keep it in monosyllables, so hopefully this will limit the opportunity for distraction: you asked for evidence for my assertion. I made two in comment #4. You can choose which one to discuss.

See? Simple.



John Cross,

You have to realize that I'm not at all up on all the errors, supposed or real of A&M. I haven't read their book, nor have I hung out around here. I have on idea where they used Celsius instead of Kelvin. I have to admit when composing my earlier message I almost made an equilivent error in that I started to calculate the temperature difference from a atmospheric composition difference based on the absolute temperature rather than the difference in absolute temperatures of two readings, but in my serious posts I try to reread my message several times to catch such errors as well as typos. It doesn't always work totally. I think Tim did something like that in his response to me. He just jotted off something which seemed correct to him but he wasn't really paying close attention to what I'd written.

Anyway, what I'm checking into is the one very simple concept of whether and to what extent it's fair to be concerned about averaging temperatures arithmatically. My working hypothesis is that there's a small but measurable difference. The question is whether it's a significant difference.

By Dave Dardinger (not verified) on 22 Nov 2005 #permalink

I see a couple of errors in your original post. First, 1 atm = 760 mmHg. Second, your heat capacities are given on a mass basis but you are using mole fractions to compute your mixture heat capacity. You need to either convert your mole fractions to mass fractions or convert your heat capacities to molar heat capacities.

Also, it's unclear to me what point you were trying to make but whatever it was I think you'll find when you make the necessary corrections it is much smaller than you thought it was.

Eek! You're right Paul. While the mistake in atmosperic pressure actually works in my favor, the fact that the heat capacity is per Kg and not per mole slipped by me and obviously reverses the affect.

Have a nice day everyone. Forget I said anything.

By Dave Dardinger (not verified) on 22 Nov 2005 #permalink

All these experiments labour under the assumption of static physical conditions.

You people are extrapolating......

By Louis Hissink (not verified) on 23 Nov 2005 #permalink

Setting aside your own weak posts in thermodynamics Dr. Lambert (irrelevant), when Mr. McIntyre defers to Dr. Essex and his thermodynamics expertise instead of engaging in this debate, you post hypocrisy at his critique of MBH because they are accomplished scientists!" The quid pro quo implication is, MBH should have been given the same deference to their expertise as Mr. McIntyre grants Dr. Essex in thermodynamics. Except the M&M critique of MBH is based on statistics, something Mr. McIntyre is expert in, and not climatology nor science in general, the former which are MBH's expertise. As the team expert on statistics, Professor Mann arguably has the most responsibility in the statistical critique by M&M -- however, the whole MBH team shares responsibility for the poor archiving practices, as well as their research sponsor and publishing agencies for not enforcing their own rules.

Perhaps if Mr. McIntyre had made critical claims of MBH on climatology grounds (instead of statistics), would you then have a case for unequal treatment of experts MBH vs. Essex -- and a deference claim of hypocrisy. Or perhaps if Dr. Essex had made equally grievous statistical errors in the book (as MBH had in their paper(s), a line you might continue to pursue), then you could claim favored treatment of Dr. Essex vs. that granted MBH? Mr. McIntyre would then respond to your statistical criticisms, and you/we could judge his fairness in his expert field. Regardless, the hypocrisy as you've framed it, just isn't there.

If this is in fact a thread resulting in part from your and Mr. McIntyre's August "last word" wars on http://www.climateaudit.org/?p=275#comment-3889 in posts around #35-55, then as Mr. McIntyre is critical of your unequal responses to McKitrick & Michaels vs. MBH, you could do same of his on MBH and E&M? Along this argument, Mr. Rabett's narrow view(s) of thermodynamics sans statistics gives you little/no ammunition.

By JohnMcCall (not verified) on 25 Nov 2005 #permalink

John McCall: You said

Except the M&M critique of MBH is based on statistics, something Mr. McIntyre is expert in, and not climatology nor science in general, the former which are MBH's expertise.

I like your argument since it shoots holes in M&M criticizm of the science of dendrochronology.

By John Cross (not verified) on 28 Nov 2005 #permalink

John Mc:

We've talked before about where you get your talking points from. You shouldn't make them up on your own. Plz get them from John A or get them vetted from duh boyz over at CA before you go forth...

And keep them short. Sheesh.