NAS Panel deja vu

As a completely impartial observer, there's a couple of opinions I've formed about Lambert and McIntyre.

1) Lambert absolutely hates the fact that McIntyre is basically a decent straightforward kind of guy (whether McIntyre's one man crusade will get anywhere is another story). Lambert secretly wishes, of course, that McIntyre was some oil company shill; 'twould make things so much easier

2) Ol' Tim, like your typical McIntyre detractor, and as I've pointed out on this blog before, cannot offer any refutation(zero, zip, zilch) of McIntrye's technical arguments, which of course leads Lambert to post banal drivel like this.

...and I'm sure the introduction of Lott into this argument must represent about 5 logical fallacies.

The earth is warming. Ecosystems are changing at rates not seen before according to our current understanding. This is not in dispute.

The levels of CO2 in the atmosphere mean that comparisons to past climates are invalid. Denialists can't explain why we wouldn't expect the earth to warm when we inject CO2 into the atm - they have no models or theories of their own - all they have is a terrible two-like 'Nnnnno!'

Fortunately, decision-makers get it (they usu. don't listen to ignoramuses) and are beginning to ask the questions on how to take steps to mitigate change (how do we get water? Where will we grow crops? What will power transportation? What sector do we cut oil out of so we can have a soft landing?) and to avoid future issues (how do we shift investment to new sectors? Where will environmental refugees go and how will that effect native populations?).

The impetus for action is too great to wait for pouty little foot-stamping denialists to be satisified (which is likely never, as there is always something to quibble about).

Best,

D

Re #1

Great call, Dennis. I fully concur with your views, although I cannot make the same claim of being an impartial observer.

There is an important distinction in how the NAS policy is worded that is not described here. The policy specifically states that biases should not be disqualifying, unless the person "is totally committed to a particular point of view and unwilling, or reasonably perceived to be unwilling, to consider other perspectives or relevant evidence to the contrary".

So bias and scepticism is acceptable, but being closed minded is unacceptable - what a refreshingly scientific approach!

Note Christy uses words like "suggests" above when drawing conclusions; indicating a willingness to change his views as new information comes in. Cuffey uses words like "buried" and "debate ended". These are subtle, but important differences in the context of the NAS policy; even if Cuffey's remarks were on a wider (but related) topic.

Dennis, your claim to be completely impartial would be more plausible if you hadn't previously stated that you believed that McIntyre had debunked the Hockey Stick. You haven't actually addressed any of the points I raised in my post. Nor are you any good at reading my mind.

Tim,

Cuffey refers to reconstructions of millinial scale - what else could these be other than the hockystick/spaghetti graph reconstructions? I would read this as explicitly including the hockeystick - minimal climate variability until anthropogenic GHGs arrived.

And taking up Dennis' point, when have you written a single sentence tackling McIntyre's statistical work?

James, the evidence for AGW that Cuffey is citing is that there HASN'T been minimal climate variability. Which is the opposite of the Hockey Stick.

When has McIntyre written a single sentence tackling the statistics in any of my posts?

"And taking up Dennis' point, when have you written a single sentence tackling McIntyre's statistical work?"

Tim, tell the one again about when you identified that M&M confused degrees with radians and the degrees McKitrick one too. they were funny!

Cuffey refers to reconstructions of millinial scale - what else could these be other than the hockystick/spaghetti graph reconstructions? I would read this as explicitly including the hockeystick - minimal climate variability until anthropogenic GHGs arrived.

Cuffey is probably referring to Von Storch's finding that the hockeystick underestimates variability and the perspectives article which was published in the same issue of science (Oct 2004).

Steve - different M&M. Not McIntyre.

James. I am not sure of your point. Cuffey has made statements about anthropogenic global warming however if you read the project scope of the NAS it says:

The committee will address tasks such as identifying the variables for which proxy records have been employed, describing the proxy records that have been used to reconstruct surface temperature records for the pre-instrumental period, assessing the methods employed to combine multiple proxy data to develop surface temperature reconstructions, discussing the geographical regions over which proxy data can be reliably extrapolated, and evaluating the overall accuracy and precision of such reconstructions.

There is nothing there about anthropogenic global warming what-so-ever. However Cuffey does have expertise in the area of using oxygen isotopes in regards to temperature reconstructions and thus in my opinion he should have a place on the committee.

Spence: You state that "Note Christy uses words like "suggests" above when drawing conclusions; indicating a willingness to change his views as new information comes in."

I would like to point out that Christy also said "This depiction showed little change until about 1850, then contains a sharp upward rise, suggesting that recent warming was dramatic and linked to human effects.[3] Since IPCC 2001, two important papers have shown something else.[4] " emphasis added.

That is a fairly definite statement and his conclusion based on two papers is not that they suggest or imply that the hockey stick was wrong but actually show it. That seems like a fairly closed minded statement to me.

Regards,
John

From Dennis Williams:

"As a completely impartial observer,"

love the irony.

Dennis Williams,
"Lambert secretly wishes, of course, that McIntyre was some oil company shill; 'twould make things so much easier'"
He is an oil company shill Dennis! McIntyre consults for the Marshall Institute which is one of the most important anti-climate change astroturf organizations in the world and heavily funded by the fossil fuel industry. According to the institute's web site, their Chief Executive Officer William O'Keefe was Executive Vice President and Chief Operating Officer of the American Petroleum Institute, on the Board of Directors of the Competitive Enterprise Institute and Chairman Emeritus of the Global Climate Coalition--all major fossil fuel industry funded astroturf groups. Among other major contributors the institute is heavily funded by Exxon Mobil, who has given them some $515,000 total since 1998 (for instance, see Exxon's corporate funding reports for 2003 and 2004). McIntyre writes for them. He is also a strategic advisor for CGX Energy, another oil and gas exploration company.
So yes, as a matter of fact this does make it much easier to demonstrate his motives for producing pseudoscience.
"Ol' Tim, like your typical McIntyre detractor, and as I've pointed out on this blog before, cannot offer any refutation (zero, zip, zilch) of McIntrye's technical arguments, which of course leads Lambert to post banal drivel like this."
Tim has addressed McIntyre's pseudoscience at length in several places including this post, this post where he discusses a paper of Ross McKitrick's that drew heavily from McIntyre's work, and this one where he discusses the McKitrick & McIntyre paper directly. These directly reference relevant peer-reviewed science and/or works that are based on it and well cited. McIntyre's misdirected efforts have also been addressed in numerous other places as well (for instance, here, here, and here. Is this your idea of "zero, zip, zilch"?
You claim to be "a completely impartial observer", but the stridency of your remarks and your carelessness in fact-checking prove otherwise.

Scott Church,

Your accusation that McIntyre is an industry shill is a serious one, and you better back it up. None of your links demostrate your assertion in any way.

Tim,

"James, the evidence for AGW that Cuffey is citing is that there HASN'T been minimal climate variability. Which is the opposite of the Hockey Stick."

Well unless I'm in some sort of looking-glass world, I thought that MBH purported to demonstrate that there was minimal climate variablity (on a millenial scale) until the 20th century. So, are you suggesting that Cuffey is an anti-HS guy? And/or is he disregarding the paleo stuff?

And again I'll ask, do you have any explicit criticisms of McIntyres work?

Scott Church,

The links you provide do not lay a glove on McIntyre. Why don't you post what you think are the meaningful paragraphs, and we can have a chat about them?

James,
I beg to differ. Every one of my links regarding McIntyre's affiliations with the fossil fuel industry either speak directly about him or an organization he is associated with. The first one is to his actual bio at the Marshall Institute site, and my links regarding that association's affiliations clearly demonstrate the institute's ties to the fossil fuel industry. The Marshall Institute is specifically mentioned in the Exxon Mobil funding reports I linked for 2003 and 2004 (do a PDF search of the documents for "Marshall"). My link to the 2003 Annual report of oil and gas exploration firm CGX Energy specifically refers to McIntyre as a "strategic advisor" and even states that Northwest Exploration Company Limited, where McIntyre was President, was CGX's predecessor company (again, do a PDF Search of the document for "McIntyre").
All of this was in response to Dennis Williams' erroneous claim that McIntyre has no ties to big oil, and each link is directly relevant.
As for the links I provided to Tim's posts, all either speak directly to McIntyre's pseudoscience or to work by his colleague Ross McKitrick that made references to McIntyre and drew at least indirectly from his work. The external references to Realclimate address the McKitrick and McIntyre hockey stick paper. In the first one their misrepresentations of the original Mann et al. paper are discussed along with various bogus claims they made regarding the use of Principle Component Analysis in the hockey stick derivation (see the "Myth 4" section). That paper also links other rebuttals and peer-reviewed research that bears directly on falsehoods in McIntyre's claims, including a reference to an upcoming paper by Rutherford et al. in Journal of Climate that has since been published. The second one goes into much more detail about the nature of PCA and how McIntyre and McKitrick misrepresent it for their own purposes. The Mann et al. paper I linked is a direct rebuttal of McIntyre and Mckitrick as well.
I fail to see how all of this "doesn't lay a glove" on McIntyre. It clearly demonstrates both his bias, and his lack of understanding of the science involved.

Sott,

You have to be kidding? Just because ther Marshall Institute carries a reference to McIntyre's bio, he's an indistry shill? Get real.

How about, instead of linking to alleged rebuttals at realclimate, you post your actual objections to McIntyre's work right here, and we can duke it out?

Same challenge applies to Tim, who has so far dodged this request.

Sheesh.

According to James:

"Scott Church, The links you provide do not lay a glove on McIntyre."

This wouldn't be the same James (i.e. Lane) who couldn't find the quote "In other words, using correct PC methodology, how much does the large-scale hockey-stick shape change if the bristlecone pine data are excluded?" on the page http://www.realclimate.org/index.php?p=128 when advised on John Quiggin's blog that this is one place where Mann had made an answer to his question? If so then there is no surprise that he can't find a glove laid on McIntyre.

There is further material regarding McIntyre's mistakes at False Claims by McIntyre and McKitrick regarding the Mann et al. (1998) reconstruction
and at On Yet Another False Claim by McIntyre and McKitrick .

James,
It was not a "reference". It was a bio detailing McIntyre's role as a hired consultant at the Marshall Institute, which in point of fact is a world class hack astroturf front group. Yes James, this absolutely does make him an industry shill. If it doesn't, please tell us what would.
My "alleged rebuttals at Realclimate" were quite specific regarding McIntyre's claim that the 20th centurt global average temperature rise in the MBH98 reconstruction (the hockey stick) was an artifact of the use of Principle Component Analysis with infilled data and the convention by which certain networks of proxy data were included. Both articles were fully cited on these points including (to name just a few);
Cook, E.R., J. Esper, and R.D. D'Arrigo, Extra-tropical Northern Hemisphere land temperature variability over the past 1000 years, Quat. Sci. Rev., 23, 2063-2074, 2004.
Esper, J., E.R. Cook and F.H. Schweingruber, Low-frequency signals in long tree-line chronologies for reconstructing past temperature variability, Science, 295, 2250-2253, 2002.
Jones, P.D., K.R. Briffa, T.P. Barnett and S.F.B. Tett, High-resolution palaeoclimatic records for the last millennium: Integration, interpretation and comparison with General Circulation Model control run temperatures, Holocene, 8, 455-471, 1998.
Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002, doi: 10.1029/2003RG000143, 2004.
Mann, M.E., R.S. Bradley, and M.K. Hughes, Global-scale temperature patterns and climate forcing over the past six centuries, Nature, 392, 779-787, 1998.
Mann, M.E., R.S. Bradley, and M.K. Hughes, Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, Geophysical Research Letters, 26, 759-762,
1999.
Mann, M.E., Ammann, C.M., Bradley, R.S., Briffa, K.R., Crowley, T.J., Hughes, M.K., Jones, P.D., Oppenheimer, M., Osborn, T.J., Overpeck, J.T., Rutherford, S., Trenberth, K.E., Wigley, T.M.L., On Past Temperatures and Anomalous Late 20th Century Warmth, Eos, 84, 256-258, 2003.
Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R., Hughes, M.K., Jones, P.D., Proxy-based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Methodology, Predictor Network, Target Season and Target Domain, Journal of Climate, in press, 2004.
Moberg, A., DM. Sonechkin, K Holmgren, NM Datsenko, & W Karlin. Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. (doi:10.1038/nature03265).
Realclimate also has another "alleged rebuttal" of McIntyre's pseudoscientific hockey stick criticisms, another one here (including supplemental PCA data here), this article on the Moberg et al. reconstruction (which by the way, independently confirms the hockey stick effect using methods very different from those of Mann et al., and for which McIntyre's criticisms would be irrelevant to even if they were correct), and this one which discusses the hockey stick in general. Again, all cited to the peer-reviewed science.
Post my "actual objections" you say? I linked these posts precisely because they do in fact contain my specific objections to McIntyre's work, and they're cited directly to his publications on each point as well as those of his colleagues Willie Soon, Sallie Baliunas, and Ross McKitrick--all industry shills as well.
As for my reliance on "alleged rebuttals at Realclimate", I've got news for you James. It doesn't get more relevant than the published peer-reviewed science on the subject!.
I'm afraid I haven't the time to "duke it out" with you until you've read what's already been provided to you.

Perhaps we could broaden the argument a bit?

The tree-ring proxies for temperature relied on by Osborne & Briffa in their Science article this month assume that there is a POSITIVE correlation between tree rings and temperature, such that

y(t) = a + x(t) .......(1)

where y is the predicted temperature, and x is the "regional growing season temperature" from the "predictor" (i.e. tree rings) (equation from Briffa et al, 2002).

But in reality tree ring widths are the result of several factors, including site slope and orientation, soils, temperature and - above all - precipitation. Recently derived tree ring data from Bighorn Basin shows that there, tree rings (x) are positively correlated (over 100 years to 1995) with precipitation, and NEGATIVELY with temperature, so that we have

x(t) = a - y(t) + z(t).....+ u(t) .....(2)

where z denotes precipitation and u all the other factors ignored by Briffa & co.

Thus Briffa's equation should read:

. y(t) = a - x(t) +z(t) ....+u(t) .....(3)

So am I right that tree rings are hardly a valid proxy, being evidently based on bogus correlations that became possible only because precipitation was ignored? If so, the MBH hockey stick and the arguments over its existence become irrelevant, for it may well be there is NO aggregate evidence that tree rings taken together constitute a valid proxy for temperature now or in the past (Osborne and Briffa 2005 could only find ten or so tree ring series that had any correlation at all with temperature, with average correlations of less than 0.5). BTW, the Bighorn Basin tree rings were cut in Wyoming as recently as 1998, although apparently Mann claims it has been "too difficult" for any new tree rings to have been cut since the 1970s. My source asks not to be cited as this data is pre-publication but clearly explosive, which may explain why Science for example is unlikely ever to publish it.

No, Tim Curtin, the proxies don't assume that. Try reading some the links that Scott posted.

Thanks Tim Lambert for the arm waving but could you be more specific?

Gee, the ad hominem attacks are getting worse, which means that the 'anti' brigade are losing the argument.

Steve McIntyre has done some of the most important work on exposing climate change fraud over the last year than anyone. The Realclimate 'rebuttals' Scott refers to, among other references, are absurd and fail to refute any of his claims. He has come out of left field for the Hockey Stick Team and demonstrated beyond any doubt that the series formed by them are statistically unsound. Beyond any doubt if you did high school stats, that is.

However, don't panic, pro-AGW believers, as the NAS panel will make sure that it doesn't upset the government funded apple cart that many of its members are benefiting from.

John C.

Thanks for your thoughtful reply to my post.

The section of Christy's statement you highlight is referring to the content of a paper, rather than his own opinion. It is entirely reasonable to say "Paper X has shown A, but paper Y has shown not A", as the statements are limited in scope to the papers themselves. But when Christy draws a broader conclusion, reflecting his opinion, he keeps it open ended.

That said, I want to avoid microscopic analysis of everything these people have said in the past. I suspect madness lies that way ;) The key point from my post is that this topic has made certain assumptions (e.g. that bias should disqualify panellists) which are not in line with stated NAS policy.

There is also another point (perhaps not appropriate here!) over whether the NAS policy is a good one. I think it has some problems; but that is the policy they have in place, so that is what they should adhere to.

Spence, I think that I agree with you!! I agree that bias on a topic should not exclude participants. I am happy with the composition of the NAS Committee and feel that both Cuffey and Spencer will add to it.

I also agree that we should avoid microscopic analysis of what was said. For example I could argue that Christy did not say that Paper X shows this and Paper Y shows that. Instead he held a view based on two papers that they were right and the opposing point was wrong. But one might accuse me of being mad to make such a fine point and - depending on the phase of the moon - I might even agree.

Regards,
John

Thanks John.

Now, in the long held blogosphere tradition, we must trade insults :-) En garde!

Seriously though, because the field of paleoclimatology is so small I don't think you can fully avoid conflicts of interest etc. So the NAS policy reflects an unachievable ideal in this case. My preference would be to change the policy in this respect to declare conflicts of interest and maintain a balance through transparency, rather than a belief that there is such a thing as a perfect committee.

My one criticism of the panel as it stands would be to have an independent statistician as well as the expert statisticians in the field of research. (i.e. add one person, but take no-one away) Statistics is a funny game and sometimes people in the field are too close to the coal face to ask the right questions.

"Stephen McIntyre has worked in mineral exploration for 30 years"

Imagine the kerfuffle had it read "Stephen McIntyre has worked in environmental protection regulation for 30 years".

See also the various references to the Association of Petroleum Geologists (in terms of awarding Crichton's book as a science book) as just "scientists".

Two things that amaze me even if McIntyre's reconstruction is correct are

1. McIntyre's reconstruction tries to suggest that the medieval warming period didn't end until well into the 15th century. According to Lamb, in his 1965 study of the evidence for the medieval warming period, "[M]ultifarious evidence of a meteorological nature from historical records, as well as archaeological, botanical and glaciological evidence in various parts of the world from the Arctic to New Zealand . . . has been found to suggest a warmer epoch lasting several centuries between about A.D. 900 or 1000 and about 1200 or 1300."

McIntyre would have us believe that Lamb was wrong by 200 years.

2. McIntyre's reconstruction completely ignores temperatures since 1980 which are now nearly 0.5 degrees C warmer than 1980 which itself was warmer than the years immediately preceeding it. If his reconstruction had not ignored these years it would have been clear that MBH98's original conclusion "Northern Hemisphere mean annual temperatures for three of the past eight years are warmer than any other year since (at least) AD 1400" was completely unaffected.

Why was McIntyre not interested in a clear presentation of the evidence?

Scott Church

McIntyre says(post and comment #35);
http://www.climateaudit.org/?p=400#more-400

I'd be curious to hear T.L.'s opinion on this.
Tim, is McIntyre an oil company shill?

Mr. Williams:

In your link Mr. McIntyre says ... it's despite explicit statements that I am not being financed by ExxonMobil or anyone else and I am not doing this to save the carbon economy. I?m doing this from my savings and I?m doing this because I find it interesting.

Now, one of the points that Mr. McIntyre has made time and again is that claims must be substantiated. It is not enough for someone to say something unless they can back it up and the information examined by others.

So have you seen Mr. McIntyre financial records? How about his tax returns? Without something to back up his claim, how can you put it forward as an argument?

Regards,
John

I thought that MBH purported to demonstrate that there was minimal climate variablity (on a millenial scale) until the 20th century. So, are you suggesting that Cuffey is an anti-HS guy? And/or is he disregarding the paleo stuff?

Cuffey cited a study which found that MBH underestimated early climate variability.

Yes, by golly - an amateur should audit the financial records and tax returns of people who insist on substantiation. Excellent point John C.

So, are you suggesting that Cuffey is an anti-HS guy?

Most people familiar with the issue (and not attempting to obfuscate, hand-wave or mendacicize) recognize that the "shaft" of the "HS" is not straight. The science has moved on. The folks who want to "bring down" the hockey stick are bashing an 8-yr old paper that has been passed by. Not that this information will stop them, but hey.

Best,

D

whoops. linky

John Cross,

I've eliminated the usual hearsay and innuendo on this subject and presented direct statements from McIntyre and your advice to me is...Just assume that he's lying. What's the point of this debate?
I would suggest that we dismiss our antagonists as liars at our own peril.

Scott,

I asked you to quote a few paragraphs that allude to McIntyre's "mistakes" and you reply with a barrage of links to Hocky Team rebuttals. I've read all these before. Why don't you provide your own argument?

Two questions:

1) Is MBH98 robust to the presence or absence of the bristlecone pines?

2) What is the r2 statistic for the 1400 reconstrction in MBH98 (and Ammann et al, since we've "moved on")

Should be simple enough to answer these two questions. You'll recall that I sent the first one to realclimate, without an answer (or indeed being posted at all)

If I may:

It is simple:

1) The lastest paper shows that the general finding is that MPRs are robust to any three proxies being taken out.

2) It's in Fig 3 (IIRC - the figger thingy with the grey boxes an' stuff with r^2 values). It's low. What's your point?

Anyway, did you notice that Murrican decsion-makers are starting to ask folk for input about a regulatin' system to mitigate fyoocher GHG emissions?

WOW! you might think. Sheesh, no one is paying any attention to the Hockey Stick at the policy-maker level! Quick! you may say. We need a better disinformation campaign!!!

*heart*

*cute smiley*

*unicorn*

Best,

D

If I may,

Dennis:

I don't want to speak for John, but I read his comment to say: 'let's "audit" and find out'. These audity things are big on some blogs, so it's probably OK to audit, don'tcha think? After all, some folk are calling for any ol' person to be able to audit stuff. Why not? Fer sure, code and stuff should be looked at. Data, too.

Lots of data should be audited, some say.

Right, Dennis?

I'm sure you'll agree.

Best,

D

Dennis,
"I've eliminated the usual hearsay and innuendo on this subject and presented direct statements from McIntyre and your advice to me is...Just assume that he's lying. What's the point of this debate?
I would suggest that we dismiss our antagonists as liars at our own peril."
Per the link to Climate Audit you provided above, McIntyre claims that he has made "explicit statements that I am not being financed by ExxonMobil or anyone else.... I am also doing this without any 'coordination'." In comment 35 at the same post he states that,
"I have no appointment or office with the George Marshall Institute, either as a âcontributing writerâ or otherwise. I have made two presentations in Washington at a meeting room on Capitol Hill in Washington co-sponsored by the George Marshall Institute. My travel expenses were paid, but I did not receive an honorarium or fee for the presentation."
He is entitled to deny whatever he wishes, as are you in his support. Nevertheless,
A)   Unless United Airlines has begun accepting Monopoly money since I last flew, paid travel expenses are compensation.
B)   As for having "no appointment or office with the George Marshall Institute", their own web site explicitly says otherwise. Not only does Marshall report that he is one of their contributing writers, they even post his presentations and writings at their web site for public download.
C)   Likewise, Exxonmobil's own corporate giving reports for 2003 and 2004 name the Marshall Institute--and therefore its staff as benefactors.
D)   According to the oil and gas exploration firm CGX Energy, McIntyre is "doing this with their coordination" as one of their strategic advisors. The company's annual reports to their investors for 2000 and 2001 say likewise.
You're right Dennis--you have "eliminated the usual hearsay and innuendo" from this discussion. You've documented McIntyre's denials for us, and it's straightforward to compare his words with those of his benefactors. If McIntyre feels that lies are being spread regarding his connections with Exxonmobil and the fossil fuel industry, then he needs to sue Exxonmobil for publicly advertizing their support of the astroturf group that employs his services, the Marshall Institute for advertizing his affiliations with them to the world and making his work available at their public web site, and the oil and gas exploration company that employs him as a "strategic advisor".
Which brings us right back to what everyone has been saying all along. McIntyre is in fact, an industry shill and has a powerful motive for promulgating the climate change pseudoscience he's become famous for. If you think otherwise, you're going to have to do better than this. All the best.

Scott, are you aying that Mcintyre is one of the Marshall Intitute's staff?

Dano said:

1) The lastest paper shows that the general finding is that MPRs are robust to any three proxies being taken out...

Dano: any average of 14 events series is quite likely to be "robust" to any 3 being removed, for that is in the nature of averages. Osborne and Briffa claim that 14 proxies are enough for total coverage of the whole of NH weather for 1200 years, even in Wymoming where the correlation between tree rings is known to be negative and even in the Arctic where there are no tree rings, but O&B can tell us the temperature there in 1066 to at least 2 decimal points (plus or minus 5C like all IPCC predictions).

McIntyre is in fact, an industry shill and has a powerful motive for promulgating the climate change pseudoscience he's become famous for. If you think otherwise, you're going to have to do better than this.

I've got to (partially) stick up for McIntyre here. Compared with most (all?) of the clowns who make the ranks of global warming skeptics, McIntyre is far and away the best of them. He does publish in peer reviewed journals (not just Energy & Environment) and he has raised some genuine concerns (such as access to data - I'm staying away from the more technical arguments as I don't know enough to judge).

He does tend to overplay his hand a bit, and climateaudit is a cesspool of idiots, but still credit should be given where it's due.

Scott, are you aying that Mcintyre is one of the Marshall Intitute's staff?

It seems pretty obvious that Scott isn't saying that. Just that he is affiliated with the Marshall Institute and derives some compensation (such as travel expenses) from them.

Even if McIntyre's temperature reconstruction from AD 1400 to 1980 is correct, one thing he always fails to show is the temperatures from the instrument record after 1980 which have risen nearly 0.5 degrees C. If he had included these in his reconstruction it would have been clear that MBH98's conclusion that "Northern Hemisphere mean annual temperatures for three of the past eight years are warmer than any other year since (at least) AD 1400" was still true.

The question is, why doesn't McIntyre ever show temperatures after 1980?

Another problem with McIntyre's temperature reconstruction is that it shows the medieval warm period ending well into the 15th century. Lamb, in his 1965 study, said "[M]ultifarious evidence of a meteorological nature from historical records, as well as archaeological, botanical and glaciological evidence in various parts of the world from the Arctic to New Zealand . . . has been found to suggest a warmer epoch lasting several centuries between about A.D. 900 or 1000 and about 1200 or 1300."

McIntyre would have us believe that the medieval warming period actually ended 200 years later than previously believed.

"Even if McIntyre's temperature reconstruction ..."

If you believe that McIntyre has actually done his own multi-proxy temperature reconstruction, then you don't understand McIntyre's work at all.

Oh, come on, Chris.

McIntyre has never proposed a reconstruction of any sort. That's one of Mann et al's canards. You have shot yourself in the foot with this one.

Ken and James,
"I've got to (partially) stick up for McIntyre here. Compared with most (all?) of the clowns who make the ranks of global warming skeptics, McIntyre is far and away the best of them."
"Scott, are you saying that Mcintyre is one of the Marshall Intitute's staff?"
I agree Ken. Though I consider McIntyre to be an "industry shill" I do concur that he's a far sight more respectable than the worst of them. And James, while the Marshall web site does not report him as being "staff" in the sense of being a salaried employee (I used the term a little loosely in my last post), they do report him as being affiliated with the institute and he does receive some level of remuneration for his services. Marshall states that they rely on his contributions to advance their agendas, and Exxonmobil funds them precisely because they benefit from them. McIntyre himself concedes that Marshall has received some $500,000 from Exxonmobil, and this figure agrees well with the figure of $515,000 since 1998 cited by Exxonsecrets.org (cited there to Exxonmobil's own financial reports to the IRS). It's a safe bet that Exxonmobil has not sunk over half a million into Marshall solely out of the kindness of their loving hearts! Nor is Marshall proudly advertizing McIntyre and his works at their site when he's not on their team.
This does not make McIntyre on the take to nearly the same degree as say, Fred Singer or Pat Michaels, but it is a damn sight further down the industry shill road than "no appointment or office with the George Marshall Institute, either as a contributing writer or otherwise", and "not being financed by ExxonMobil or anyone else...." All the best.

Ken Miles said (1st March 01.50 am):
Scott, are you saying that Mcintyre is one of the Marshall Intitute's staff? It seems pretty obvious that Scott isn't saying that. Just that he is affiliated with the Marshall Institute and derives some compensation (such as travel expenses) from them.

Ken,I have news for you: Tim Lambert has been employed for the past ten years by none other than John Howard, chief Kyoto denier in Australia. More than that he has attended conferences at which his presence was most likely also largely funded by said JH. Meantime, apart from biting the hand that feeds him, I notice that he graciously makes himself available to students for 3 hours a week, probably rather less than he spends running this absurd blog. I also note that his publication record apart from said conferences is rather sporadic albeit brilliant in its own way (nut none are related in any way to climate issues). No doubt he will think the above is unfair, but then he has defamed the late Julian Simon for "deceit" on the basis of one incorrect statement in a 700 page book (almost certainly more in just that book than said Tim Lambert has published in his lifetime so far, but he's a bit coy on the word count in his publication list).

Joking like the above aside, can we not agree that affilations and funding are less important than the intrinsic worth of what one has to say, whether it be said by Mann, McIntyre, or Lambert?

In James' opinion:

"McIntyre has never proposed a reconstruction of any sort."

What's the problem? Forgotten how to click on a link, McIntyre's temperature reconstruction from AD 1400 to 1980, the "Recalculated" curve in the graph? There's also their neighbouring page, "Corrected Version" curve which for reasons I have yet to determine is significantly different from their first page. You can also check out their recontruction in their 2005 Energy and Environment paper (third part of figure 1).

In James opinion:

"McIntyre has never proposed a reconstruction of any sort."

What's the problem? Forgotten how to click on a link, McIntyre's temperature reconstruction from AD 1400 to 1980, the "Recalculated" curve in the graph?

There's also his neighbouring page, "Corrected Version" curve which for reasons I have yet to determine is significantly different from the curve on his first page.

You can also check out his reconstruction in his 2005 Energy and Environment paper (third part of figure 1).

Mr Williams: you said I've eliminated the usual hearsay and innuendo on this subject and presented direct statements from McIntyre and your advice to me is...Just assume that he's lying.

Well, as Dano, and Mr. Church have said the point is that if you are going to make claims then you should be able to verify them. In fact, I am surprised to hear that you think the opposite and that we should accept the word of researchers without looking at their data.

Regards,
John

Tim Curtin, I am employed by UNSW, not John Howard. It says so right on the sidebar so you have no excuse for getting it wrong. If you find the truth about Julian Simon so unpalatable, I suggest you stop reading this blog.

nanny_g_s said on 3/1/06 03:04 AM:

If you believe that McIntyre has actually done his own multi-proxy temperature reconstruction, then you don't understand McIntyre's work at all.

Absolutely! The man has done no work to show the robustness of the denialist hypothesis [increase in atm CO2 has not warmed the planet]. Nor has anyone else. It's all hearsay.

The claims of the denialists and contrascientists have no empirical backing.

Simple, yet complex.

Best,

D

Chris,

You've misunderstood McIntyre's point. Mann claimed that his procedure was robust to the removal of dendroclimatic indicators and to the statistical method applied. McIntyre ran the method by removing just one of the dendroclimatic indicators and found the result changed. The graph demonstrates the large change in the result, the graph is not there as an alternative reconstruction.

This point is important so I'll repeat it: the graph is not to show an alternate reconstruction, it is to demonstrate the original reconstruction lacks robustness.

The large change in reconstructed temperature shows that minor adjustments (that should be irrelevant) to the MBH98 algorithm or data produce entirely different reconstructions, therefore the result is not reliable.

McIntyre is not the only one to make this claim. Burger and Cubasch drew the same conclusion in their later paper (cited below), by applying a different tweaks to the algorithm. You will also note Burger and Cubasch present graphs of temperature in their paper. They also do not claim these are valid reconstructions, they merely present them to show the lack of robustness.

(Burger, G., and U. Cubasch (2005), "Are multiproxy climate reconstructions
robust?", Dec 2005, GRL/32, L23711)

1. Why all this fetishization of an original, outdated paper? Do folk in the UK fetishize, say, the Spitfire and insist it should be used in today's battles?

2. Why all the focus on just one indicator among scores that show warming of the planet?

3. How come the fetishizers don't atomistically scrutinize the CO2 levels in the atmosphere?

4. Don't the fetishizers realize the rest of the planet has moved on? Can't they find something else to atomistically quibble about? Like, say, the information Blair used to mislead his people in war?

Best,

D

Tim Lambert - and who funds the UNSW and the leisurely lifestyle it affords if not John Howard's Commonwealth Government? Your blog supports more deception than you have ever found in Simon, including the continuous slanders against McIntyre.

Dano,

I'm not really interested in engaging in a political debate on a blog, I find they are generally pretty futile. So I'll avoid most of your overtly political comments. I'm sure there are plenty of other bloggers willing to take you up on that side of the argument; I'd rather stick to the scientific aspects.

The issues raised in Burger and Cubasch paper are most certainly not out of date, and these issues could well apply to many of the other multi-proxy reconstructions, including some of the most recent ones. Although with everyone keeping their data so close to their chest, just applying these simple tests can be time-consuming. So the implication we are all concentrating on just one old paper is simply false. Paleo climate reconstructions in the scientific literature will go on for a long time yet, and we will learn new things from this.

Understanding the errors and limitations in Mann et al. will help future reconstructions to be more accurate - that is how science works. Understanding any errors and limitations in McIntyre and McKitrick will help future temperature reconstructions also. But misinterpreting what was written in a paper (as Chris has done above) teaches us nothing.

Dano,

I asked:

"2) What is the r2 statistic for the 1400 reconstrction in MBH98 (and Ammann et al, since we've "moved on")"

You replied:

"2) It's in Fig 3 (IIRC - the figger thingy with the grey boxes an' stuff with r^2 values). It's low. What's your point?"

Fig 3 in MBH98 is for the period 1845-1901. As the "proxies" in this series contain actual instrumental temperature records, it is not surprising that the reconstruction for this period is skillful.

We know from McIntyre's emulation that the r2 statistic for the 14th century step is approximately zero, that is, it has no skill, this part of the reconstruction is worthless. We also know from Mann's source code that he calculated r2 for the earlier stages but did not report the adverse statistic. That is the point.

But I suspect you already knew that.

Spence: I hate to spoil the fun when we were starting to agree, but I think that a certain amount of "misinterpertation" is understandable. I note that McIntyre is fairly selective about what he corrects and is not above letting the misrepresentation stand.

That said, I do agree with your last paragraph (at least the first two sentences).

Regards,
John

Tim C, you get the award for the worst contribution to this thread. Most ad homs, least content. You are doing a fine job however in confirming my prejudices about global warming skeptics.

PS. Learnt about how temperature scales work yet?

Dano, you said: Don't the fetishizers realize the rest of the planet has moved on? Can't they find something else to atomistically quibble about?

Your link to a proposed bill in the US Senate for a mandatory market-based GHG regulatory system shows a flow chart for GHG in the US that omits any mention of nuclear energy, for the good reason that it omits no GHG. One has to be suspicious of the sincerity of non-sceptics who cannot bring themselves to campaign for adoption of nuclear power as the cheapest and safest way of reducing GHG. AS for safety and storage etc, here's a hint, from Physics Today, Dec 2003, p.34: "an area the size of a football field is adequate for storing the spent fuel from hundreds of years of a power plant's operation...."

John,

Hey we were never going to agree on everything!

I would stress that my comment above does not say misinterpretation does not happen. A certain amount of misinterpretation is inevitable, because language and communication aren't perfect, and we don't always get the time we need to analyse scientific papers, etc., in sufficient detail to get the full picture. However I stand by my point that misinterpreting papers rarely teaches us anything (other than perhaps how to be better communicators!) as it simply muddies the water.

As for letting misinterpretations stand - this is a pretty highly polarised debate, and to be honest I think you just have to accept that each side is only going to point out the mistakes of the other side, and rarely from their own side. Sure it does happen occasionally but it is the exception rather than the rule. I suspect the best you can hope for is that people will back down and admit their own errors when a clear enough argument is presented to them, and there are certainly no shortage of people on both sides of the debate that won't even do that.

I hope this post makes sense. It seemed very waffley when I was writing it!

We know from McIntyre's emulation that the r2 statistic for the 14th century step is approximately zero, that is, it has no skill,

Yes. Like I said the .02 is in the paper somewhere. But,

It is now 2006. We are not in 1998. 2006. Not 1998.

2006.

In 2006, we have ~a dozen or so subsequent MP reconstructions, all of which have greater skill and are used in concert with dozens of utterly different indicators across scores of disciplines that say roughly the same thing.

That is: there are, literally, piles of other empirical evidence to point to that say roughly the same thing.

Policy-makers are given executive summaries of the piles of evidence that say roughly the same thing.

They are not given one chart from 8 years ago. They are given executive summaries of cross-disciplinary empirical findings.

The majority of them indicate the climate is changing at a likely unprecedented rate.

So, the point you bring up? It matters not a bit.

No one cares about that one chart from 8 years ago, inflated by some people to make it seem as if it is the only thing decision-makers see when they are briefed.

Get it? That constructed narrative has been passed by. Buh-bye. TTFN. Toodles. Ciào!

So. The thing you're concentrating on?

SFW.

Jus' sayin'.

*heart*

Best,

D

Gosh, thanks Tim Curtin!!!!

Do you want me to help you find an e-mail addy so you can share your umbrage with our electeds?

Best,

D

According to Spence_UK:

"You've misunderstood McIntyre's point."

Have a look at the third part of figure 1 and read the accompanying text in McIntyre's 2005 Energy and Environment paper.

McIntyre's point was that MBH98's reconstruction could only be achieved if some particular proxies were included AND if the erroneous choice of principal components used by MBH98 were used. His point was that if you choose his method which he believes is correct (notwithstanding expert mathematicians disagreeing with him) then his result is robust to changes in data. The third part of figure 1 in McIntyre's 2005 Energy and Environment paper is produced using what he believes is a correct method for producing a reconstruction. If you don't call something produced by what you believe is a correct method for producing a reconstruction, a reconstruction, then what do you call it?

In any case, any possible outcome that McIntyre has produced ignores the temperature rise since 1980 so anything he has done does not change MBH98's conclusion that "Northern Hemisphere mean annual temperatures for three of the past eight years are warmer than any other year since (at least) AD 1400".

So the question remains, why doesn't McIntyre ever show temperatures after 1980?

Chris, I think you're really off the deep end here. I'll throw out this life preserver and hopefully we can reel you back in:

McIntyre is a statistician. He doesn't do climate reconstructions, he just checks the work of others from a statistical perspective.

Hope that's clear.

"If you don't call something produced by what you believe is a correct method for producing a reconstruction, a reconstruction, then what do you call it?"

A correction to the MBH98 method, regardless of the veracity of that method.

Dano:

"Yes. Like I said the .02 is in the paper somewhere."

No it's not, and you know that. Stop lying.

Many of the problems with MBH generalise to the other multiproxy studies, specifically the selection and worth of proxies. Read Burger and Cubasch.

Jus' sayin'.

I said:

"If you don't call something produced by what you believe is a correct method for producing a reconstruction, a reconstruction, then what do you call it?"

James said:

"A correction to the MBH98 method, regardless of the veracity of that method."

Oh, so no-one produces reconstructions only "methods". And if roses had a different name they wouldn't be roses any more. Yeah sure.

But since the only thing that denialists like James will even consider is the gospel according to McIntyre, here is what McIntyre says in MM05, page 81:

"The strong negative bias of the two outlier series is evident, as is the closer relationship of the 6 series average to the MM-type reconstruction."

So McIntyre says he's responsible for a type of reconstruction, not a type of "method", or "result".

In any case, all of McIntyre's "results" or "methods" or whatever you want to call them completely ignore the temperature record after 1980. The question is, why?

Chris,

McIntyre is very clear that the temperature graph he presents - like the original MBH98 - has no statistical skill. He does not claim anywhere that his graph represents historical temperature. He describes it as a "reconstruction" only to give it the same context as Mann's graph, but he is quite clear in all cases that neither has any merit. By discussing it (as you have above) in terms of what that historical temperature "means", you are entirely missing the point.

Please show where McIntyre claims his "reconstructions" skillfully estimate historical temperature. Likewise, Burger and Cubasch present "reconstructions", 64 of them to be precise, as opposed to MM's 3, but equally claims none of them have statistical skill.

McIntyre doesn't ignore the post 1980 instrumental record. His point is (that you seem to be struggling with) is that the historical temperature estimation has no skill (have I made this clear enough yet?). Just like Burger and Cubasch claim the historical temperature record has no skill. If you accept this point, made by McIntyre, McKitrick, von Storch (04), Burger and Cubasch (05) you are comparing the post 1980 instrumental record to a bunch of random numbers; therefore you cannot make the claim that the 1990's were warmer than the last 600/thousand years, because you do not know accurately what the temperature was in the last 600/thousand years. The only flaw in the logic is that you believe "one of the 3 curves must be right", whereas McIntyre's claim is "none of the 3 curves are right".

Spence: You said: "As for letting misinterpretations stand - this is a pretty highly polarised debate, and to be honest I think you just have to accept that each side is only going to point out the mistakes of the other side, and rarely from their own side. Sure it does happen occasionally but it is the exception rather than the rule. I suspect the best you can hope for is that people will back down and admit their own errors when a clear enough argument is presented to them, and there are certainly no shortage of people on both sides of the debate that won't even do that."

Actually, Spence that is an awfully bleak conclusion. I think that the BEST we can hope for is a whole lot better than that. In reality, it doesn't really matter whether the protagonists on each side back down, admit errors, etc. What REALLY matters is that this highly visible discussion on an important, even vital, topic, on several blogs (each with their own cluster of views, values, attitudes, beliefs; their own cast of supporters, decryers, hangers on, lurkers etc) is airing the topic in a way that could never have happened before the development of the internet.

It has to be a good thing for people involved in the debate, climate scientists and others, to be aware that their work will come under scrutiny (perhaps I should say intense scrutiny) in this day and age. It is a good thing if scientists thinking about publishing take special care about their work, and attend to what is expected of good science. And it is a good thing that more people are learning, very quickly I'll bet, what good science really is. And it is a good thing that peer reviewers will take more care about their work, and a good thing that science journals will begin insisting that scientists comply with their already high standards re data archiving and the like.

And it must be a good thing that science lecturers around the world will have their students following this "debate" to demonstrate how, in fact, science works. What exactly ad hominem attacks are. The consequences of not following sound scientific practice. etc etc.

It can only be good if major policy decisions are based on better quality science, and a better informed public. And my best hope is that THAT is the outcome we will achieve from this debate.

We should acknowledge the dilemma that some of the brave scientists are in, suddenly faced with the intensely bright spotlight of blog scrutiny, when none of us really understood just how powerful blogging could become - even one year ago.

Scientists who did their work and prepared their papers for publication in an earlier, long ago, era had no idea that their work would come under such scrutiny. But now the spotlight of blog scrutiny has fallen on their work, the practical solution for those scientists is surely to review their work to see if it actually does meet the suddenly widely understood high standards. It it does meet the standards, good. Go with it. If it doesn't, surely the smart thing to do is to say, "Hey, I was young, it was a different era, I didn't really understand. I got it wrong. How can we work together to do a better job in future." Not too surprising an admission in this incredibly complex world we live in, where none of us can hope to know more than the smallest sliver of that which is to be known.

So all power to you bloggers, from every side. It is good work you are involved in, one and all.

Well, James, I'm not going to get drawn into an atomistic quibble about an old paper that has, today, at best the tiniest of utilities, if used to brief anyone at all.

It's a non-starter.

And I don't have the paper with me, but Mann et al were explicit in the paper that wrt the multiproxy calibration going back to the year 1400 they had not enough data to make useful predictions. I also recall the figger 3 shows extensive areas of grey pixels that indicate lack of robustness in those areas. Anyone with any experience reading papers at all would have read this paper and said it needs work.

But, the constructed narrative works on the rubes who can't understand or read the paper so they fall for the line that Mann et al were hiding something.

It's just not true, and your line that I'm lying is, in fact, wrong. Too bad for your little constructed narrative you want to believe because it sound so good to you. See my comment above for context on your narrative and how wrong it is.

HTH,

D

mtb,

I think your points are off at a slight tangent to mine. I wasn't really addressing the utility of blogs, my comments weren't really even specific to blogs, more to the wider climate science debates, both in and out of the scientific community.

Bias is a very important factor, even at a peer-reviewed level. If you haven't seen it, I'd recommend a look through some of Roger Pielke Jr's thoughts on the subject over at Prometheus, where he has discussed the influence of bias in peer-reviewed journals.

It is simply a fact of life that we are quick to criticise those we disagree with, and give those who we agree with a pretty loose rein. That doesn't make an argument false, it doesn't make blogging a waste of time, it is just a straightforward recognition of the realities of the way people apply critical thought and debate. Awareness of this practicality can only help to understand arguments. What counts isn't the speed of the criticism, or who makes it, but the validity of the statements made.

Out of curiousity, who do you think might use your quote - "Hey, I was young, it was a different era, I didn't really understand. I got it wrong. How can we work together to do a better job in future." - and why? This is the sort of thing that I believe is a rare event (not impossible, but rare) because it means people have to change strongly held beliefs.

Dano:

"And I don't have the paper with me, but Mann et al were explicit in the paper that wrt the multiproxy calibration going back to the year 1400 they had not enough data to make useful predictions. I also recall the figger 3 shows extensive areas of grey pixels that indicate lack of robustness in those areas"

Pitiful.

What is pitiful? that I can't recall the paper verbatim, or that you used an argument that can't hold water?

But enough of this.

It is now 2006.

In the year 2006, we have ~a dozen or so subsequent MP reconstructions, all of which have greater skill and are used in concert with dozens of utterly different indicators across scores of disciplines that say roughly the same thing.

That is: there are, literally, piles of other empirical evidence to point to that say roughly the same thing.

Policy-makers are given executive summaries of the piles of evidence that say roughly the same thing.

They are not given one chart from 8 years ago. They are given executive summaries of piles of cross-disciplinary empirical findings.

The majority of them indicate the climate is changing at a likely unprecedented rate.

So, the point you bring up? It matters not a bit.

No one cares about that one chart from 8 years ago, inflated by some people to make it seem as if it is the only thing decision-makers see when they are briefed.

Get it? That constructed narrative has been passed by. Buh-bye. Long gone.

Best,

D

What's pitiful is that you contest a point I made, then when caught out protest that it "doesn't matter/moved on".

I would have thought a discussion of the skill of the multiproxy reconstructions was quite germane to a thread about, er, multiproxy reconstructions. But there you go.

According to Spence_UK:

"you are comparing the post 1980 instrumental record to a bunch of random numbers".

In that case we'd better cut off funding for all paleo-climate research since all they produce is a "bunch of random numbers".

If McIntyre is so good at understanding analyses of paleo-climate data, when is he going to do something useful and publish his reconstruction? Or are you saying that through sheer bad luck, virtually all of the proxies suddenly become inaccurate before 1500, all of the tree-rings, all of the dO18 in caves, in ice, in sediments, in coral and every other dO18 capture process, all of them are useless before 1500? When is McIntyre going to produce a reconstruction that shows that MBH's actual results, which are the thing that really matters, are wrong? Several more recently produced reconstructions have been done using different methods from MBH98. McIntyre hasn't said anything about most of these methods. Mann referred to some of these and to papers testing the validity of them in http://www.dailykos.com/story/2006/1/20/7194/94155 .

If you really believed that someone used the wrong method to get the right results in the past well fine but how long does it take for you to realize that the only thing that matters now is that we have the right result now. When will the contrarians move on to arguing the thing that really matters, i.e. that we have the right result now?

BTW Spence_UK also said: "but he (McIntyre) is quite clear in all cases that neither has any merit." Yeah sure, he prints a big graph in his publications which is significant in a particular way and then buried somewhere in the text says it's just a random number.

Chris,

Actually, McIntyre has quite a lot to say about Mann's Daily Kos interview:

http://www.climateaudit.org/index.php?s=daily+kos

BTW, unlike your pal Dano, you seem to think that MBH's results are "the only thing that really matters". I thought the paleo team had "moved on"?

Chris,

"In that case we'd better cut off funding for all paleo-climate research"

This is called a hyperbole. You've taken something I said and drawn a ludicrous conclusion from it, and are trying to pin that ludicrous conclusion on me. If anything, my opinion that the existing reconstructions are unreliable suggests that perhaps we need to put more effort into paleo-climate research.

I see we're also trotting out the usual fallacies about "negative" research. Negative research (i.e., this doesn't work, this paper is not correct) is just as valid and valuable in the scientific context as "positive" research. Statistical studies have underlying assumptions that aren't always obvious. By getting a better understanding of these underlying assumptions and the statistical qualities of the data, you can pave the way for better research. That's why Steve has been involved in peer review for various paleo climate papers in climatology, that is why he is giving presentations to the NAS panel. What he has to say is clearly important, even if he doesn't answer your pet question.

By the way, your statement,

"Or are you saying that through sheer bad luck, virtually all of the proxies suddenly become inaccurate before 1500, all of the tree-rings, all of the dO18 in caves, in ice, in sediments, in coral and every other dO18 capture process, all of them are useless before 1500?"

Is simply more hyperbole. I'm not saying that at all. I am saying the existing paleo climate constructions have a number of weaknesses both in data and methodology, and citing more than one paper (not just MM, but vS and BC) to back this view up. None of the papers say anything like what you've written above. But the papers do suggest that existing global temperature reconstructions are very unreliable.

Incidentally, Burger and Cubasch found that the reconstruction they tested began to wobble as late as the end of the 19th century, and had fallen apart by 1600. So no, there isn't some strange cutoff at 1500.

Science doesn't stop, Chris. People will be trying to do bigger and better paleo climate reconstructions for the next hundred years, I suspect. Perhaps more accurate, more detailed, higher bandwidth, greater length etc. That isn't a bad thing in my view.

Chris O'Neill: "When will the contrarians move on to arguing the thing that really matters, i.e. that we have the right result now?"

Hi Chris: Well if you are right about AGW,I have to tell you that IPCC's forecast of up to 4C warming has already been achieved this summer but about 50 years early in Canberra, Australia, yet life goes on very comfortably (even if not so well in Perth, WA, with its coldest ever summer). My garden blooms as never before. So IPCC is right and "climate change is the greatest threat facing humanity" according to Tim Flannery, and worse than terrorism, according to Tony Blair (if I lived in Baghdad I would rather take my chance with "climate change" (summer temperatures having always been above 40C for the last 5000 years) than with Sunni/Shia terrorism. What then? I myself have this week sold my Excel coal shares and bought Toro uranium, even though the Prospectus quotes the Ausralian Labor Party's Manifesto's commitment that no new uranium mining will be permitted if it ever returns to power, alhough it is also committed to ratifying Kyoto in full. BTW perhaps you (and Dano and Ken Miles) could tell us what you-all have done to put your money where your big mouths are. I recognise that clowns like Tony (WMD) Blair see no choice but to go nuclear - when it comes to picking investments it's good to go with the flow (until just before the bubble bursts, which perhaps would be when our fearless 3 see the light, I hope they let me know in time to sell Toro).
But I wonder if we "do have the right result now". Dendrochonology began at the University of Arizona. Some of its researchers' recent study of tree rings at Bighorn Basin shows clearly a NEGATIVE correlation between tree rings and instrumental temperatures there since 1895. Karl Popper suggested some 50 years ago that if an hypothesis was rejected just once by empirical data, then it would have to be revised or discarded. It is the inability/refusal by Mann's hockey team to admit that all too many of their proxies fail this test, leading them to frauds worthy of Ken Lay's Enron, which has prevented the emergence of a scientific consensus on whatever "climate change" there may be in Huston or Canberra.

This is Tim Curtin, from the link that Ken posted:

That emissions of carbon dioxide are responsible remains to be proved, and you of all people should know there is no econometric modelling that demonstrates this essentially implausible result, given that the increase in atmospheric CO2 of about 100 ppm over 200 years (a growth rate of 0.15 per cent p.a.) has only reduced the non-CO2 components of the atmosphere from 99.972 ppm to 99.962 ppm - small changes may have big effects, but that such a further change over the next century (0.01 per cent) could raise the average temperature in Britain by 50.00 per cent in 20-100 years (as claimed by the IPCC as well as by Bob May in Sydney recently) seems unlikely (albeit a delightful prospect to refugees from that climate like me).

Says it all, really.

"Says it all, really."

Thanks Tim Lambert. When Celsius whoever he may have been picked freezing point for 0C on his scale, then if IPCC and Flannery cite temperature changes of +4C as "the greatest threat facing humanity", 4C sounds big (since average annual temps in UK are around 10C), but if the IPCC cited all temperatures in Kelvins, then the % equivalent of an increase of 4C would not sound very alarming. So I am all in favour of citing all temperatures in Kelvins.

Nobody except you talks about % changes in Celsius because it's completely meaningless. A change of 4 degees C is a change of 4K. Duh.

Tim Curtin: Does the above quote that Dr. Lambert provides still represent your point of view?

Spence_UK: I can still agree with some of what you wrote above. However I would like to clarify none thing. You stated that I am saying the existing paleo climate constructions have a number of weaknesses both in data and methodology, and citing more than one paper (not just MM, but vS and BC) to back this view up.

Now, M&M's argument is that the statistical results for the 15th are not valid. vS provides an interesting take on things but still shows that the current warming is larger than previous periods. While I have not read BC, I have read the review of it by others (including M&M) and I gather from it that while there are a number of possible reconstructions depending on your prior assumptions, none show previous warm periods being warmer than the current ones.

So to summarize, according to M&M, you can't tell if we are warmer than anyother time. The others imply that we are currently in an "unprecedented warm period". For those who are interested in paleoclimatology reconstructions and comparing them to today's temperature the results tend to support what has been said all along.

However I belong more to the field that tends to not put a lot of weight on the value of comparing current temperatures to previous temperatures. If we are unsure of temperature, how certain are we of the forcings that cause temperature (I know I am asking for arguments from some members of the climate community)?

What I find interesting about BC is that most of the reconstructions do follow MBH quite closly but when they differ significantly, they differ by being a great deal cooler than the MBH. If there were the correct ones, it could have serious implications for the climate sensitivity value implying that climate will be more sensitive than less to changes of CO2. To me this is the important lesson of BC.

Just some random thoughts.

Regards,
John

John,

I think you're missing the point. Neither M&M or B&C propose alternative reconstructions. They're pointing out (in different ways) that the reconstructions alluded to are not robust.

One has to go further than John Cross. First there is an important difference between climate variability and climate sensitivity. Variability is (at least in my view) a pseudo-random variation in climate attributable to internal causes which may have chaotic components. Sensitivity is the response of the climate system to external forcings such as land use, volcanoes, fossil fuel burning, industrial emissions, solar changes. To an extent all of the external forcings can be put on a common basis in terms of energy fluxes at the top of the atmosphere.

vS&Z point out that the Mann reconstructions imply a very low value to climate sensitivity. M&M and various other denialists hold that the intrinsic variability is so high that one cannot claim that the current excursion is outside the natural variability. This is very different from vS&Z

John,

It is a mistake to treat the graphs generated by either McIntyre or Burger and Cubasch as temperature reconstructions. They are outputs from a statistical method, achieved by mixing and matching methods that have been declared as valid by one of the many multi-proxy studies in existance. They haven't claimed their alternate histories are "better" than MBH, but they are checking the reliability of the results.

The problem with having a large number of different methods that claim equal validity, is that if they give substantially different answers, then the statistical significance attached to each of those is weakened. For example, if I have 20 different methodologies that I can apply, and each produces a quite different result, the chances are one of those results will be significant at the 95% level. But that arrives by chance alone; it doesn't mean we have discovered something of merit. Burger and Cubasch identified no less than 64 different methodologies by cross comparing different multi-proxy studies. And most of them have no merit, even when tested against just one loose measure of statistical skill.

On the other hand, if the results turned out to be robust to changing methodology, the statistical significance would not have been weakened.

But B&C don't stop at identifying the lack of robustness. They look into possible causes, and say there is no one simple cause, but they suggest the extrapolation of the linear relationship between the proxy and the temperature record is most likely to be one of the major issues. They point out that proxies are calibrated over a narrow range, but then that linear assumption degrades as you move further from the calibration region. At best, it will remain linear but the error grows as you move from the centre, but at worst the linear relationship could break down completely outside the calibration interval.

The point here, is that the areas where it may have been warmer in the past, coincide with the areas on the multiproxy studies that have the greatest error - and an error that the current group of studies substantially underestimate. This leads to the conclusion that the studies are simply too unreliable in their present form to deduce that it is warmer today than at any time in the last 1000 years.

vS is a different analysis - he claims that the MBH method underestimates past variability, which means the graph could have gone both up and down by a much larger margin. He doesn't put a figure on this though - it is dependent on the proxies. His reconstructions are based on model outputs and therefore not related to "true" historical temperature, but an abstract "artificial" historical temperature, so it is impossible to draw conclusions about "true" previous temperature from this paper.

Of course everyone wants to interpret these results in their own way to determine whether or not climate change is an issue. I have my own take on this, which involves fractals, self-similarity, scale invariance and the Hausdorff dimension. But that debate is for another day :-)

James tap-danced:

What's pitiful is that you contest a point I made, then when caught out protest that it "doesn't matter/moved on".

nooooooo, I said what you said about MBH98 'hiding something' isn't true.

THEN I said the issue moved on.

I would have thought a discussion of the skill of the multiproxy reconstructions was quite germane to a thread about, er, multiproxy reconstructions. But there you go.

It is. Relaying falsified talking points not based in fact isn't really a discussion, though. It's astroturf.

Thanks!

Best,

D

James misspoke:

BTW, unlike your pal Dano, you seem to think that MBH's results are "the only thing that really matters". I thought the paleo team had "moved on"?

I've said no such thing. Something is preventing you from comprehending the written word.

Why do you need to spread falsehoods to make your claim? Oh, wait: that's all you've got. Carry on.

Oh, and what Rabett & Cross said.

Best,

D

James: I agree that M&M do not and I think I was quite clear in saying so. I am not as convinced as you about the results of BC. From what I understand (and if anyone has a link to the paper I would appreciate it - the one on ClimateAudid didn't work) they said that there were a number of prior assumptions that had to be made in order to reconstruct. They showed the range of these reconstructions and while they all vary, there are none that show a period warmer that the current time.

Eli: Many have gone much further than me - to quote WC "if I have not seen further it's because giants have been standing on my shoulders".

I agree with your comments about vS and I was indeed referring to climate sensitivity.

Regards,
John

Spence: I have been cross-posting so I didn;t see your comment. I need to get the paper and see what it says. I know that McIntyre reflects your view, but I have seen others that feel different. However I suspect that we will indeed have different interpretations of it.

My final thought for now is that if in fact the calibration relation breaks down in warm temperatures then the climate sensitivities based on paleo-reconstructions are again underestimating climate sensitivity.

Regards,
John

John,

I suspect the link at ClimateAudit was removed by request. Scientific papers come with a copyright, and obtaining a copy should result in the author and journal receiving an nominal (but small) fee, unless either the author or journal choose to give it out freely. I had no luck in finding a copy on the web, so I'm assuming that the authors have not made it freely available.

You can acquire it free from the AGU (if you have a subscription) or for a small fee (if you don't) from here:

http://www.agu.org/pubs/crossref/2005/2005GL024155.shtml

Alternatively, there should be an academic or technical library near you that will stock the journal, which may work out cheaper, especially if you have a lot of articles you wish to catch up on.

I let my subs lapse else I'd have quoted from the BC paper by now, so I apologize (apologise) for not lending my historic services to this debate.

Hopefully I'll have them back up within two weeks, but that requires me driving to Seattle and giving a signature (no fax accepted).

And let us note that, for the most part, this 'debate' is not being carried out because of the flood of contradictory papers being published in the journals...

Best,

D

Tim Lambert:

Yes a change of 4 in C is the same as a change of 4 in k, but why does not the IPCC use k? In my UK example, its predictions sound more alarming when stating UK's annual average temperature will rise from 10C to 14C (40%) in 50-100 years than if one says it will rise from 287.15k to 291.15k (1.4%). Presentation is everything when advocacy reigns, as IPCC showed with its use of the hockey stick as backdrop. Or are you saying that measuring change is meaningless?

I suspect this is too narrow of a cultural reference for folks down there:

I read the comment immediately above and think of the sound that Scooby and Shaggy made when they started to run, but instead their feet ran in place for a while before they started going forward.

It's dodgy, I know, but so much more amusing than trying to imitate a tap-dancing sound...

Rooby-doo!

Best,

D

Better yet, Tim, let's restate the predicted change in Megakelvins that way it sounds even smaller.

And if that doesn't work, there's always the GigaKelvin...

Dano, Scooby Doo was a fixture on Oz TV. I'll give you a narrow cultural reference: I think Curtin's line would work as a hard-hitting question delivered by Norman Gunston to the IPCC.

James says:

"I thought the paleo team had "moved on"?"

You're not getting the point here James. The paleo team have moved on to better methods and testing of methods. The results haven't changed very much from MBH98.

Tim Curtin,

It is not that you *shouldn't* use percentages when comparing temperatures in Celsius, it is that you CAN NOT. Shall we reiview the basic levels of data?

Nominal: Values have no numeric significance nor any logical ordering; 1 for grapes, 2 for strawberries 3 for cement trucks. And so on.

Ordinal: Values have logical ordering, but that's all. Like a ranking system. 0 for strongly disagree, 1 for disagree, 2 for don't know or care, 3 for agree, 4 for strongly agree. You can not add, subtract, multiply or divide these values. You can, however compare them (qualitatively, that is).

Interval (ding ding ding!): As implied by the name, these values have a consistent "interval size," but they have an arbitrary zero point. So the distance between 4 degrees C and 5 degrees C is the same as the distance between 856 degrees C and 857 degrees C. You can therefore add and subtract these data, but you may not, I repeat: may not, multiply, divide or compare them in "ratio" terms. Bringing us to...

Ratio: values that have a natural, logical, zero point and consistent interval size. Like Kelvins (because zero means zero), or weight in kg, or population.

Dano:
I believe Rich Hall--formerly of SNL and a lesser known HBO series in the 1980s called "Not Necessarily the News"-- had a "sniglet" (made-up word that should be a real word) for the revving up of one's feet before running. I think he called it the "Flintstep."

Spence_UK wrote:

"I see we're also trotting out the usual fallacies about "negative" research. Negative research (i.e., this doesn't work, this paper is not correct) is just as valid and valuable in the scientific context as "positive" research."

The point I was trying to get at is that McIntyre is not very good at understanding analyses of paleo-climate data, even if he's only admitting to not being very good at it himself. His criticisms of MBH's use of Principal Components Analysis are rubbish. If he really understood PCA he would know that there is no fundamental need for the data to be centered to get a valid set (albeit with origin shifted) of Principal Components. The Principal Components are just the values of the data resolved onto the eigenvectors of the data covariance matrix, with the only proviso being that the eigenvectors have to pass through the centroid of the data when the data is not centred at zero. The data-noncentredness makes no difference to the covariances, so it makes no difference to the covariance matrix eigenvectors. And contrary to what McIntyre says, there is no need to normalize (or standardize as he calls it) the data to have variance equal to one. Refer to a tutorial to see that normalization doesn't need to be used. McIntyre also has the idea that there is no formal rule for deciding how many PCs are needed. Yes, I'm sure he's looked for one.

Spence_UK also wrote:

"Incidentally, Burger and Cubasch found that the reconstruction they tested began to wobble as late as the end of the 19th century, and had fallen apart by 1600."

"fallen apart" meaning up to 0.5 degrees C different from MBH. As I've said before this 0.5 degrees C does not change the conclusion that it is now warmer than anytime since 1400. You don't need to be very accurate to reach this conclusion. On a related point, I don't know why so many people are obsessed with whether the medieval period is warmer than now when there is little argument that it was quite likely warmer, say, 8000 years ago. Why is it so important to some people that the medieval period in particular was warmer than it is now?

Spence_UK wrote later:

"B&C point out that proxies are calibrated over a narrow range, but then that linear assumption degrades as you move further from the calibration region."

One of the advantages (if you can call it that) of the 20th century for calibrating proxies is that the 20th century covers such a wide temperature range, from little ice age temperatures at the beginning to warm age temperatures at the end. This enables paleo-climatology to test proxies over this range against instrument temperatures. So any unknown non-linearity in proxies is not going to come into play unless the paleo-temperature is outside the calibration range. As far as I know the paleo-proxies are always below the highest temperature values occuring in the calibration period, so there's no chance of underestimating temperature due to unknown non-linearity.

Spence_UK also wrote:

"Science doesn't stop, Chris."

Nice to be reminded of the bleeding obvious.

Kenneth Blumenfeld: you said "It is not that you *shouldn't* use percentages when comparing temperatures in Celsius, it is that you CAN NOT."

Of course, economists have known for about 200 years that you can have ordinal, non-additive, utility, but not cardinal - additive - utility. However most ordinary people - especially very ordinary people like Tony Blair - when told about this or that numerical increase in something like temperature will if told "4C up on 10C will be catastrophic" might well think, "gosh, you are right, that sounds big or even, that's 40%, crikey, this is worse than bombs on the underground". A few if not Blumenfeld will say that's only 4C on 287k, perhaps not so scary. My view is (1) that the changes in the atmosphere as between CO2 and non-CO2 are inconsequential and even self-correcting (water vapour has been described as forcing as well as feedback, so more of one forcing combined with less of another may not matter much), but even if the change is to more forcing from CO2 from less from non-CO2, there is still also a concomitant decline in non-CO2 feedbacks when CO2 increases. But let's assume that the outcome is AGW of 4C or k on 10C or 287k, what's the problem, especially in Baghdad? I know of no definitive assessment that warming to that extent is harmful. There is no proven linear relationship or any other between polar melting and sea-level rise, and Lovelock would probably agree that there are likely to be self-correcting factors at work (eg more rain uplift from the oceans). Otherwise there is massive evidence for the beneficial impact of CO2 on agricultural and timber yields, and for the fact most people prefer warmer climates to colder. Finally, when nearly all true believers in AGW except Lovelock unite to prevent adoption of nuclear energy as the proven most cost-effective way to reduce CO2 emissions whilst maintaining living standards, can we have anything but scorn for both their science and their integrity?

Chris:

"McIntyre also has the idea that there is no formal rule for deciding how many PCs are needed. Yes, I'm sure he's looked for one."

Which rule do you prefer, Chris? Scree test? Eigenvalue rule? Preisendorfer?
There is no formal rule for retention of PCs (or otherwise stated, there are several).

Chris,

Thanks for another fascinating series of mischaracterisations on McIntyre's arguments. Nice of you to throw in a logical fallacy as well - I'll get to that later. The key that I've been trying to describe here, is that the multi-proxy methods are not robust, either to data or variations of method. A statistical method that is not robust should not be relied upon.

Anyway, on to your points.

If you argue both centred and uncentred PCA are valid, then the reconstruction must be robust to this decision. But, as shown by both McIntyre, Burger and Cubasch, it isn't. The problem isn't so much uncentred PCA is fundamentally wrong, the problem is that it has consequences for the robustness of the results.

You then go on to claim that McIntyre doesn't think there is a formal method for selecting PCs. This is simply false. McIntyre has talked about a number of formal methods for selecting PCs, but points out none of them tie in with the PC roster used by Mann. MBH claims to use Preisendorfer's "Rule N" - discussed extensively on ClimateAudit (so how you can claim McIntyre doesn't know about formal rules just shows how unaware of his arguments you are) but this step cannot be reproduced either. (The code W&A made available simply read off the PC roster archived at Mann's SI, so they haven't even tried to replicate this step).

On his blog, McIntyre provides references to allow people to find out about PC selection criteria such as the Kaiser-Guttman criterion; bootstrapped Kaiser-Guttman; Scree Plot; Broken-stick; Proportion of total variance; Sphericity test; Bartletts test of the equality of λ1; Lawleys test of λ2, bootstrap eigenvalue-eigenvector. Hardly indicative of someone who knows nothing about PC selection. I thought "Broken-stick" was a particularly aptly named method.

"Fallen apart meaning 0.5 deg C from the original" - that's enough to show lack of robustness, but isn't the most important aspect. By changing these parameters (which shouldn't matter), you get a wide range of different values for statistical skill; by cherry picking one with high significance, you make the results appear more meaningful than they actually are. Unfortunately this cherry picking can be applied to the cross validation statistics as well as the calibration period, turning the cross-validation into another calibration, further undermining the results.

"One of the advantages (if you can call it that) of the 20th century for calibrating proxies is that the 20th century covers such a wide temperature range" - This is an example of inserting your conclusions into your assumptions. This is the logical fallacy of affirming the consequent. Find out more here:

http://en.wikipedia.org/wiki/Affirming_the_consequent

By assuming the 20th century covers such a wide range of temperatures, of course you'll find that the 20th century had the warmest period of it. But that doesn't teach you anything about the truth.

"As far as I know the paleo-proxies are always below the highest temperature values occuring in the calibration period" - no they're not. Read Burger and Cubasch. Just the abstract explains this much. Remember proxies indicate local, not global temperature. Nobody else (that I know of) is claiming temperatures have never been this high in some localities.

"Nice to be reminded of the bleeding obvious." - it's a shame you had to be, by suggesting "When will the contrarians move on to arguing the thing that really matters, i.e. that we have the right result now?" - clearly showing you want the science to stop. I don't think we have the right result now, and from their statements, I believe von Storch, Burger, Cubasch, McIntyre don't either. Some obviously do think we have the right result. The debate - and the science - will continue.

Tim Curtin: nuclear energy... the proven most cost-effective way to reduce CO2 emissions whilst maintaining living standards,

Keep asseting thatm Tim. Eventually you may convince someone, if only yourself.

Tim Curtin, in the passage that you wrote and I quoted above, you calculated percentage changes in Celsius. You weren't doing to object to something you now allege the IPCC is doing -- you did it as part of an argument that a small percentage change in atmospheric compostion could not cause a large percentage change in Celsius temperatures. You're not helping your credibility by now claiming that you've known all along that this was invalid.

Just an extra note.

I didn't bother reading Chris' link to "a tutorial" on PCA, because I'm quite familiar with how PCA works. After posting, and out of morbid curiosity (I'm a sucker for punishment), I thought I'd take a peek. (NB. You have to knock out the space in the link for it to work properly).

Scanning quickly through it, it is a simplistic - but not bad - introduction to PCA; a bit low-level for someone with reasonably strong maths skills, but well presented for someone who doesn't. What made me laugh was that in the document it states (pg 12, 3.1 step 2):

"For PCA to work properly, you have to subtract the mean from each of the data dimensions."

I'm not saying I necessarily agree or disagree with this point, the real answer is, as ever, rather more complex than that, but you are using a reference to demonstrate one point that actually disagrees with an earlier point you make.

Is that ever a wise move in a debate?

The temperature of the Earth without an atmosphere is 256 K and the temperature with the atmosphere. The current global average temperature is ~288 K. That is a difference of about 32 K. Meaningful percentage changes should be stated relative to that figure, i.e. a change of 3K is about 10%. Ice ages were globally about 7K lower, i.e. ~20% lower

Ian Gould: I am sure you know the cost of electricity generated by nuclear energy varies by plant depending on age and type and discount rate for valuing the capital cost component. The largest all-in (including capital) costs of 14 nuclear power plants cited by the OECD's NEA is one in Japan, at US$70 per kWh with a discount rate of 10%; One in Canada comes in at less than US$40, and there's one in Korea at US$30. Fuel costs alone were much less of course, as little as US$3 per MWh in the Korean case (but would be appreciably higher at today's costs of uranium). The OECD's NEA paper by Bertel and Morrison ("Nuclear Energy Economics in a sustainable development perspective") shows that at a 5% discount rate the all-in generating cost falls to as little as US$25 per MWh for the Canadian plant for which the fuel cost is US$9.

Data from US Utility Data Institute on nuclear energy costs in USA from 1981 to 1999 are in a range between US$20 and US$30 per MWh and by 1999 were just below the comparable cost of coal fired power at US$21, and well below oil and gas, in constant 1999 US$.

Australia's NEMMCO publishes average electricity prices which can fluctuate widely in the course of a week, eg first week in February, from as little as A$15 per MWh at weekends (US$11) to as much as A$57.48 (US$42) on weekdays (NSW, 1st Feb 06). Other things equal, it would appear that nuclear power could well be competitive even with coal in Australia.

This conclusion was independently confirmed by Martin Sevior (School of Physics, Univ of Melbourne) in the Australian Financial Review as recently as 1st March 2006: "Nuclear power now an affordable option".

Those that recall my dust up with Dano on the r2 statistic in MBH98 might like to have a look at this:

http://www.climateaudit.org/?p=564#comments

I wrote:

"Nice to be reminded of the bleeding obvious."

to which Spence_UK replied:

"- it's a shame you had to be, by suggesting "When will the contrarians move on to arguing the thing that really matters, i.e. that we have the right result now?" - clearly showing you want the science to stop."

When I was talking about moving on I meant moving on from the method of MBH98. The thing that really matters is getting the right result regardless of the method used. I can't see how this means that I want the science to stop, even though apparently it's clear to some people that this is my meaning.

Regarding Burger and Cubasch, Mann says they didn't study their most up to date methods as in Proxy-Based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity
to Method, Predictor Network, Target Season, and Target Domain .

"The thing that really matters is getting the right result" - exactly, and B&C have shown that the current results are not reliable enough to be called the "right result". But even when we find a result which actually holds water, there is always the potential for that to be overturned in the future. That is what science is all about. Keep questioning what we think we know.

I haven't looked at the REGEM method in great detail yet (I've downloaded the MATLAB, fixed the errors that prevented the archived code from running, but not yet analysed it in much detail).

The REGEM method certainly seems to address one problem of PCA, in that PCA demands that there is no missing data, and some process must be put in place to handle this.

But this isn't the problem identified by Burger and Cubasch. Their main concern is that outside of the calibration interval "temperature" extent, there is no guarantee that the proxy data remains linear and even if it does, the extrapolated error grows with the distance outside of the calibration interval. I don't see anything in the paper you cite which addresses specifically that concern. If you can point me to a particular paragraph that you feel addresses this point, that would be useful.

Yeeees, james, I said it was .02.

What's your point? that a blog wants to keep hammering an old paper? How is that news?

D

"B&C have shown that the current results"

According to Mann, B&C don't test all the current results.

"But even when we find a result which actually holds water, there is always the potential for that to be overturned in the future."

Yes, that's the perfect climate skeptic argument. Just say the results showing we have a problem could always be overturned in the future so just ignore them.

"Burger and Cubasch's main concern is that outside of the calibration interval "temperature" extent, there is no guarantee that the proxy data remains linear and even if it does, the extrapolated error grows with the distance outside of the calibration interval."

You'd be best to ask Mann or his colleages if they think this is still a problem but it appears that the main problem with extrapolation error, both linear and non-linear, is for temperatures colder than the calibration range, as shown by figure 7 in Burger, Fast and Cubasch's "Climate reconstruction by regression - 32 variations on a theme". In this figure there are very few reconstruction proxy values above the warm end of the calibration proxy values. So the reconstruction proxy values near the warm end would generally be quite well covered by the calibration proxy values. So the reconstruction would not be particularly sensitive to extrapolation error near the warm end. As long as uniformitarianism applies, the warmest reconstructed temperatures should be as accurate as the reconstruction proxies allow. Of course, uniformitarianism might not apply and that's another issue.

"that the main problem with extrapolation error, both linear and non-linear, is for temperatures colder than the calibration range" - that statement is not correct in the non-linear case. If the response is a quadratic ("inverted U") for example - certainly an appropriate model for tree rings - warmer temperatures could appear below today's levels. There are plenty of other proxies that exceed 20th century values by a large margin, but those proxies seem to be less likely to be selected in paleoclimate studies. Unfortunately justification of proxy selection criteria is rarely laid out and appears to be a little "ad hoc", which should be anathema to statisticians.

"According to Mann, B&C don't test all the current results." - B&C question an assumption at the heart of most of the multiproxy studies, whilst it is true some of them may not be affected, at present it is not clear which are and which are not. Perhaps if we could see some of the data that we could work it out more easily.

"You'd be best to ask Mann or his colleages if they think this is still a problem" - I have tried asking questions on RealClimate in the past and, mysteriously, they never appear. I gave up bothering some time ago, as it is not worth the time taken to compose the questions. I'll find time to do a bit more digging into the RegEM procedure. I can see the merit in the RegEM procedure (procedural mechanism and error model for missing values) but at a top level I just can't see how it addresses the issues raised by B&C.

I'm not sure what you mean by "Just say the results showing we have a problem could always be overturned in the future" - I'm not sure what "problem" the paleoclimate reconstructions show we have. I'm interested in the detail of the science, not the broad brush conclusions people try to draw from it (which are more often than not politically motivated, on both sides of the debate).

"If the response is a quadratic ("inverted U") for example"

You have to assume worse than that. You have to assume non-uniformitarianism because if such a response actually occurs it should also occur in the warm times of the twentieth century. In nearly all of B&C's alternative reconstructions the middle of the twentieth century has average proxies reaching higher values than any other time back to 1400. If there really was an inverted U response and if it really was warmer in the past then the proxies in the past should at least reach the middle twentieth century average before turning down.

"- certainly an appropriate model for tree rings"

Care to give a reference?

"There are plenty of other proxies that exceed 20th century values by a large margin"

If that's true then they're not showing an inverted U response. Is there any evidence of significant inverted U response? One thing about the climate is that because of its variability, even if it was warmer on average around 1400, there would still be some years in the 20th century that were substantially warmer than most of the years around 1400. Any undetected non-linearity could only affect the small fraction of the years in the reconstruction that could have been warmer than the warmest years in the twentieth century.

"I have tried asking questions on RealClimate in the past and, mysteriously, they never appear."

I know McIntyre has had an article asking for questions asked at realclimate that were ignored. If he hasn't formalised this it might be worth asking him to set it up. It would be easier to pick out the questions with substance if all such questions were in one place. I know that some people try to ask repeated questions based on incorrect information originating from McIntyre, such as the idea that the data in the ftp://holocene.evsc.virginia.edu/pub/MBH98/TREE/ITRDB/NOAMER/BACKTO_140… directory only has bristlecone pine proxies removed when it actually has the entire North American tree ring data set and Queen Anne data set removed. This data made up 70% of all of the proxy data used by MBH98 prior to AD 1600 and was removed from the MBH98 dataset by McIntyre and McKitrick in their original 2003 E&E paper. I'm not surprised that the contributors to realclimate are not interested in answering questions based on this misinformation.

Chris,

You seem to still be pushing a point that the proxies never show higher values than the twentieth century. This simply isn't true. Sargasso, Conroy, Indigirka for example, all of which have been used on the various multi-proxy studies at some point.

On the topic of inverted U - no, proxies being warmer some time ago does not falsify the inverted U hypothesis, as the modern period might not be at the optimum growth condition (peak of the U) - it could be either side, so higher values earlier are not incompatible with this theory.

I'm surprised you're questioning the inverted U. To me, it seems obvious that a tree will have an optimum temperature for growth, too hot or too cold and it will grow less well. Also, the same tree species will have a different optimum temperature at different sites, and may be on different parts of the curve at the same time.

Anyway, you asked for a reference. Here's an example:

http://www.fs.fed.us/rm/pubs/rmrs_p032/rmrs_p032_124_135.pdf

Page 128, figure 4 shows how photosynthesis varies with temperature for some of the very trees used in MBH98.

Again, I'm not quite sure what your point is regarding RealClimate. I wanted to ask the people at RealClimate a question, not Steve McIntyre, I don't see how posting on McIntyre's blog would help get an answer. If they were willing to answer the questions, they would have posted up and responded. I can't see them going over to McIntyre's blog to answer there instead.

Looking at one of M&M's articles, their comment was:

"MBH98 did not report the results adverse to their conclusions from calculations excluding bristlecone pines (contained in the BACKTO_1400-CENSORED directory)."

It does not say the bristlecones were the sole exclusion (as you imply), it just says that a run was performed without the bristlecones, that would have caused adverse results, but the adverse results were not reported (indeed the paper claimed that the results were robust to the removal of all dendroclimatic indicators). At best you could argue McIntyre could have worded it a bit better, but his conclusion that adverse results were not reported stands, and claims over the specifics of that run seem to me to be a weak straw man.

O'Neill said:

a buncha stuff

Surely decision-makers across the planet look at just one paper and don't ask their scientists to look in other areas to help them decide about stuff. Makes it easier to think, dont'cha know.

And I'm not surprised that some want to focus, atomistically, on one tiny fraction of all information.

Certainly this is better than looking at the rates of ecosystem change we are currently experiencing measured in plant movements uphill and northward, ice-free days on new England and upper Midwest lakes, population changes, biodiversity impacts, invasive spp., changes in population species richness and diversity, fishery collapse, British Columbia pine devastation...

[takes deep breath]

...population crashes in Amazonia, Madagascar, changes in glacier mass balance across the globe, coral bleaching, changes in precip frequency and intensity, changes in runoff, melting permafrost, arctic biota changes, increasing temperature, O3 hole in Ant....

[takes deep breath]

...human appropriation of NPP changes, LU/LC indices changes such as NVDI, BIBI changes in urban streams due to changes in hydro regime, drought in US SW, SW Eur, Murray-Darling impacts, salmon pop. crashes in US Pacific NW...

Ah, you get the picture.

So, it is far more useful to atomistically quibble about one paper - from eight years ago - than it is to step back - today - and behold the planet-wide changes and challenges wrought by human enterprise.

Thank you, O'Neill, for helping spread the good news that the scientific data about climate change is based on misinformation.

Your misdirection will make it easier for me to sleep tonite! Things are getting better, Tinkerbell!

Thanks, O'Neill!

Best,

D

Spence, I am one of the people who seems to feel that the Sargasso is not a good proxy to use. Or rather I am unsure what it is a proxy of. Is it a proxy of sea temperature (unlikely given the thermal inertia involved) or is it a proxy of current location. If the latter, then it may actually be a proxy of the NAO but a more definite linkage would be necessary.

Also, I don't have the paper in front of me but I seem to recall that there were issues with salinity as well.

I am not familiar with the others proxies you cite, but I can assert that the sargasso has been overused by some who don't understand (or want to understand) the paper - Drs S & B for example.

But I am with Dano - lets flag it and move on. There are a huge number of other proxies that do seem to indicate we are in a time of warmth higher than in the last thousand years. I look forward to future studies that incorporate them as well as the past ones.

John,

You might be leaning on one of my pet peeves there, watch out :-)

Selection criteria for inputs into statistical studies have to absolutely strict and quantitative, never subjective because it is too easy to add bias - even subconciously (this is a well known and observed effect).

Every single proxy out there has other dependencies. Tree rings are dependent on sunlight, availability of water, competition and fertilisation effects. Borehole temperature measurements are dependent on fractures and water contamination. dO18 measurements are dependent on precipitation.

If you make an argument "I don't like proxy X because it is contaminated by other influences" then you are introducing immediate bias into the process. If you reject one proxy this way, you must reject them all. This is one of my greatest concerns about the various multi-proxy studies: not so much the data that are put in, but why data are left out.

This is a real weakness from a statistical point of view. Statistical studies in other fields have been thrown out because an apparently rigid selection criteria turned out to be ambiguous or tunable, yet in multi-proxy studies more often than not we have no clear reason for rejecting proxies at all.

"There are a huge number of other proxies that do seem to indicate we are in a time of warmth higher than in the last thousand years" - and there are a huge number that suggest we aren't. The ones I picked are deliberately chosen as ones used in the current multi proxy studies (Sargasso sea is in Moberg '05). There are many out there which, for some reason, don't get chosen.

I would agree this kind of debate in the blogosphere won't settle this, but the current crop of multi-proxy studies won't settle it either.

(Sargasso sea is in Moberg '05).

In fact if you look hard enough on the net you can find where I questioned Moberg's use of the Sargasso sea data.

I would agree this kind of debate in the blogosphere won't settle this, but the current crop of multi-proxy studies won't settle it either.

Actually, we do seem to be somewhat in agreement. I think that paloclimatology is an interesting topic (and fun to argue about since I suspect that most of us don't really have a clue about the science) but it is of limited use in today's look at global warming. If there are statistical questions on the proxies then there are even more on the forcing functions.

That is why I think the way forward is by looking at current conditions not past conditions. Papers like Philipona or Minschwaner or even Annan are examples of this.

So as I said - flag it and more on - nothing to see here folks.

"In fact if you look hard enough on the net you can find where I questioned Moberg's use of the Sargasso sea data."

I had a quick google for your name and Sargasso and I note on RealClimate you asked the question as above - but this does not counter my argument above. If you reject Sargasso on the subjective basis that it has confounding influences then you must reject all proxies. You are allowing your own bias to select proxies that conform to the argument you are making.

The points you (and Dano) subsequently raise are to do with the wider issue of global warming, which is really an entirely different debate to that of historical temperature reconstruction (IMHO). If you try to tie a result from historical temperature reconstruction to a view on AGW then you are simply likely to introduce more bias into the debate (because it is such a polarised issue). I think the science would progress more effectively if people didn't try to link the two so closely.

Spence, I don't think you understood my point. I don't think that the Sargasso sea temperature is a bad proxy, I don't think it is a proxy at all. This would seem to be a fairly well defined criteria for rejection. Of course this is an opinion on my part - obviously Moberg disagrees with me and I suspect he knows a fair bit more than I do about paleoclimatology.

If you try to tie a result from historical temperature reconstruction to a view on AGW then you are simply likely to introduce more bias into the debate (because it is such a polarized issue)

Well, yes and no. I agree that the reconstructions do seem to polarize the debate, but if you take them away then there is a fair amount of agreement (at least in the published work). The only other area where I could see a similar polarizing issue was that of atmospheric temperatures (NAS convened a panel for that as well). That now seems well on its way to being resolved so I don't think that it is such a polarized issue these days.

John,

My point is an important statistical point. Sure, subjectively, you can question the merit of the Sargasso sea (you still don't lay down a criteria other than your opinion). I can sit here and claim that the Bristlecone pines aren't a temperature proxy. Gavin Schmidt can claim the Thames freezing doesn't make a good temperature proxy. It may not be obvious to you - but it is obvious to a statistician - that we would all be guilty selecting and rejecting proxies on subjective criteria and introducing bias. On such a loose reason as you provided, applied fairly to all proxies, would result in all proxies being rejected. You may have convinced yourself this isn't the case but your reasoning would not bear up to statistical analysis.

My key point here is that very few of the multi-proxy studies have clearly defined criteria for selecting proxies, and the selection should not be on the whim of an individual (I'm talking about the initial selection process, not the secondary cut that is often performed and described in some papers - although even this secondary cut is rarely adequately described).

I certainly wouldn't trust a statistical study without this, which is one of the reasons I don't think the current crop of studies have much credibility.

If you try to tie a result from historical temperature reconstruction to a view on AGW then you are simply likely to introduce more bias into the debate (because it is such a polarised issue). I think the science would progress more effectively if people didn't try to link the two so closely.

This presumes the folk doing the data collectin' do such a thing.

Oh, wait: you must mean the folk who chatter over policy implications after the data are collected.

Never mind. I'm sure you don't confuse the two - completely separate - issues.

Best,

D

correction to one of my comments above: I mistakenly replied to O'Neill rather than Spence.

Apologies.

Best,

D

Spence: We appear to be at an impasse. I am not saying that the Sargasso sea is a broken proxy, but rather that it is not one at all - however perhaps this horse (or thread) is dead.

I notice that Tim has a page up where he is offering to match pledges to The Global Fund to Fight AIDS, Tuberculosis and Malaria. In light of these enjoyable discussions I will show my appreciation by offering to match any pledge that you make (up to $25 - Tim is richer than I am). This means that anything you pledge gets increased by a factor of 3.

Goodnight
John

"You seem to still be pushing a point that the proxies never show higher values than the twentieth century."

I'm not saying that at all. I'm saying that some of the proxy values in the twentieth century are higher (at the warm end) than most of the past proxy values over periods of say, 50 years. There were periods when a small fraction of the proxy values were higher than the highest values that occurred in the twentieth century but this could only at worst have affected a small fraction of years in any given period of 50 years. Considering also that there is noise in the proxies, this issue is only going to come into effect in those years where unusually high temperatures coincided with noise peaks so the fraction of affected years would be even less.

" Sargasso"

Yes well, this indicates that you didn't realise what I was talking about which is annually resolved proxies such as the ones used by MBH. The Sargasso foraminifera proxies have a resolution of 50 years at best so they won't pick out the individual warm years. Since MBH didn't use this type of low resolution proxy you can't say their results are affected by a possible shortcoming of low resolution proxies. Also BTW, Moberg's Sargasso proxy only goes up to 1925 but that doesn't make much difference anyway because of the low resolution.

In any case B&C's issue was about linear extrapolation error which is clearly a problem at the cold end. They didn't appear to be very interested in non-linear error so I don't know if it's that much of an issue among experts. If it isn't then there's not much point in non-experts talking about it.

" I'm surprised you're questioning the inverted U. To me, it seems obvious that a tree will have an optimum temperature for growth, too hot or too cold and it will grow less well."

We're not talking about trees in general here, we're talking about trees in locations that are specifically chosen to cause high sensitivity of growth rate to temperature, i.e. near the cold limit at which the trees can grow. In such locations the temperature is a very important factor limiting how fast it can grow and it's usually a lot colder than the optimum growing temperature. This is why the locations are usually near the high-altitude or high-latitude tree-line. So in these circumstances the response is not likely to be near an inverted U.

" Again, I'm not quite sure what your point is regarding RealClimate. I wanted to ask the people at RealClimate a question , not Steve McIntyre, I don't see how posting on McIntyre's blog would help get an answer."

Well if you had logged your questions somewhere then someone might have been able to tell you why they doesn't get responded to at realclimate rather than just pointlessly whining about it to people who don't even know what your questions were.

"Looking at one of M&M's articles, their comment was:

"MBH98 did not report the results adverse to their conclusions from calculations excluding bristlecone pines (contained in the BACKTO_1400-CENSORED directory)."

It does not say the bristlecones were the sole exclusion (as you imply),"

BTW, McIntyre says elsewhere "If the bristlecones are excluded from the network and principal components are calculated without the bristlecones, there is no hockey stick shape."

Yeah sure, none of this is misleading and I don't know why people try to ask questions at realclimate based on being mislead in this way.

McIntyre's "conclusion that adverse results"

caused by removing 70% of all the proxy data used by MBH98 prior to AD 1600

"were not reported stands."

Removing 70% of all the proxy data has an adverse effect. Gee that's a surprise.

Dano, I was trying to be polite by not drawing attention from your little Freudian slip, but since you insist on drawing attention to it yourself: we're talking about historical temperature reconstruction, not hysterical climate contemplation. (Hysterical seemed appropriate from all the hyperventilating going on. You should see a doctor about that. Seriously, I worry about it.)

"This presumes the folk doing the data collectin' do such a thing. Oh, wait: you must mean the folk who chatter over policy implications after the data are collected." - you present a false dilemma; I'm referring to neither of these. The people who go out and drill holes in things can't subconciously bias results, because they can't see the results before they do the drilling. But there are thousands upon thousands upon thousands of holes drilled, yet only a small percentage of these make it into the multi-proxy studies. The decision here is made with the data visible a priori, which should require a quantified and unbiased approach. This seems lacking in the studies I have seen. I'm not talking about the second cut here either (selection of temperature sensitive sites) but the first cut (selection of which sites to test).

John, we aren't going to get agreement on this topic. "Broken proxy"/"bad proxy"/"not a proxy at all" are just different ways of applying a subjective threshold, which unfortunately will have skew or bias depending on the contents of the results. As I said, a statistician would follow this argument, but a plain old scientist may not. Subconcious bias is prevalent even in such mundane fields as particle physics. In such a polarised field as climate, you can imagine the problems are likely to be much greater.

To both Dano and John: I recommend you read "MYTH 9: SCIENTISTS ARE PARTICULARLY OBJECTIVE" from http://www.usc.edu/dept/education/science-edu/Myths of Science.pdf

John: regarding donating to charity, I generally give to smaller charities; large charities these days create a strong brand image and are getting a larger and larger slice of the pie, leaving some small organisations marginalised. Since I don't really engage with Tim I don't feel any great compulsion to give to his preferred charity, however if you are willing to accept then I will donate a nominal amount to a small UK charity of my choosing, you can then give to a charity of your choosing. I hope you consider this "in the spirit" of your request.

"I'm not saying that at all. I'm saying that some of the proxy values in the twentieth century are higher (at the warm end) than most of the past proxy values over periods of say, 50 years."
And some of them aren't. Local and global temperature variations cannot be compared in this way. My original point was that if you go much outside the calibrated region of the twentieth century, you cannot guarantee linearity. Nothing you have said has addressed this claim. This point has been made in the scientific literature, and is presently being discussed. In fact, there has been a decline in tree ring growth of some supposedly "temperature sensitive" sites in the late 20th century which has been the cause of much discussion: most of it remains conjecture, but non-linearity has to be right up there as a candidate.

The straw man about Sargasso that you have posted up is unbelievable. I lost count of the number of logical flaws in your statement here. I gave three example proxies, one of which is a tree ring chronology providing annual data for over a thousand years, and you reject them all because you were talking about MBH (I was talking about proxies and multi-proxy studies in general) and one of the examples I gave "isn't appropriate" (even though the others could be). This is wrong on so many levels I don't know where to start. Aside from the fact that I gave a range of proxy types, including low frequency and high frequency: if the high frequency data differed from the low frequency data, wouldn't this indicate a problem that needed to be resolved anyway? Also, you suggest MBH seeks high bandwidth data to pick out individual warm years; if it was capable of doing this, it would have a halfway decent cross-validation r^2. It doesn't. So much for that idea.

Even worse, since there are plenty of proxies showing elevated values compared to today's temperature, your observation that these appear not to be present in the B&C paper begs the question: why not? Was the sample selection in MBH biased?

"In any case B&C's issue was about linear extrapolation error which is clearly a problem at the cold end"
B&C raised more than one issue. They mention both linear extrapolation problems (clearly a problem at both ends when you select an unbiased set of proxies) as well as the possibility of non-linearity.

"We're not talking about trees in general here, we're talking about trees in locations that are specifically chosen to cause high sensitivity of growth rate to temperature, i.e. near the cold limit at which the trees can grow"
Yes but as discussed already this can only be tested for the calibration period, and may not hold outside of that interval.

"So in these circumstances the response is not likely to be near an inverted U."
Only if you assume previous temperatures are close to the temperatures in the calibration interval, as I stated earlier, this is the logical fallacy of affirming the consequent (does it feel like we are going around in circles here?). Given that some of these sites are not reflecting the recent 20th century warmth, why would they have reflected earlier warmth?

"BTW, McIntyre says elsewhere "If the bristlecones are excluded from the network and principal components are calculated without the bristlecones, there is no hockey stick shape." "
Yes, that conclusion is based on his own runs using his own emulation of MBH98, so it stands on its own.

"Removing 70% of all the proxy data has an adverse effect. Gee that's a surprise."
MBH claimed in their paper that the NH reconstruction was robust to the removal of all dendroclimatic indicators. If they hadn't made this claim, it might not have been a surprise to find out it isn't. Given what they claimed, yes it is a surprise.

But there are thousands upon thousands upon thousands of holes drilled, yet only a small percentage of these make it into the multi-proxy studies. The decision here is made with the data visible a priori, which should require a quantified and unbiased approach. This seems lacking in the studies I have seen. I'm not talking about the second cut here either (selection of temperature sensitive sites) but the first cut (selection of which sites to test).

This presumes many of those holes are adequate for study.

I'm quite sure you won't want the holes cored in, say, red alder in a river bottom. There are few suitable sites for a reason.

And, yes, everyone appreciates the fact that your e-friends want retroactive data storage rules. Good on ya. Until then, if your boy want's folk to share data with him, your boy shouldn't act like such a...a...well, hmmm...if he wasn't, he wouldn't appeal to that group, would he?

Best,

D

"This presumes many of those holes are adequate for study."

Nice straw man. I'm not claiming we shouldn't be selecting sites. I didn't even mention archiving (which is an issue, but for different reasons). I'm saying that site sampling should be transparent and quantified explicitly in any study that leans heavily on the use of statistics. Lack of transparency and subjective selection criteria results in subconscious bias in statistical studies. Well known and well documented effect.

Statisticians understand why this is necessary, although not all scientists do (and I wonder if this is part of the reason you are struggling a bit with the concept). It is related to the link I posted above - the myth that scientists are objective.

Introducing a proper, clear, verifiable selection criteria that eliminates the risk of bias is straightforward, and failure to do so is just lazy. It is also important to show robustness to sampling and data issues, which cannot effectively be tested properly with the current crop of studies.

Spence_UK said: It is related to the link I posted above - the myth that scientists are objective.

Spot on, and you have shown conclusively that Kyoto is a naked emperor, devoid of any empirical substantiation for its hypothesis.

Timmy pecked out on his keyboard:

[there is a] myth that scientists are objective...[s]pot on, and you have shown conclusively that Kyoto is a naked emperor, devoid of any empirical substantiation for its hypothesis.

Aside from the fact that the science behind Kyoto has empirical substantiation, policy action is not rooted in empiricism [see, it's the knowledge behind it that is], that policy action has no hypothesis, and you are mixing up science and policy,

It matters not whether scientists are objective. Of course they are not.

Your hand-waving and misstatements only work for dumb people.

What matters is whether scientists follow the scientific method in their material gathering and analysis. The scientific method is a construct to eliminate bias.

So please. Take your widdle FUD phrases where they'll work, sir - where the rubes hang out. That ain't here.

Best,

D

Spence, Tim:

That is a great site you have found Spence. Tim I would encourage you to read all the Myths involved. I found 1, 2, 3, 6, 10 and 13 to be very interesting and if only more people had read these there would be far less debate.

Spence: The thing about Tim's charity was that a contribution by you would have resulted in a matching by me and both of our contributions would be matched by Tim so it would have increased 3 times. If you can find me another cahrity where someone will match my contribution 3 times I will probably contribute (if I feel that it is a valid charity - no contributiuons to the Spence retirement fund).

John

Coming late to this party. The 'hockey stick' paper seems a useful straw man, because the ins and out and controversies of statistical analysis can keep many people unfruitfully occupied for a long time, while distracting from the ongoing data collection (I note that glacier melt is speeding up, arctic temperatures are rising, the distribution of cyclones is globally broadening in area and season, and areas of drought are increasing in the US, while Europe is losing some of the Gulf Stream warmth), all consistent with the current models for global warming. Instead of discussing facts such as these, let's focus on a fraction of the data, and never update it. PCA is both robust (data normalization is not as crucial in many contexts as fetishists would have you think) and weak (with number of principal components leading to different findings. Automated rules can be applied, but their use will vary depending on the context (especially the reliability of the individual observations), and reliance on automated rules without comparison of over and under-extraction is dangerous.
It's nice to see that so many of the general public have now decided to become experts in this area, though.
As for the progress of science, normal science proceeds by reducing uncertainty (making predictions more accurate), new science proceeds by answering a niggling question, while pathological science proceeds by sticking to one point, insisting on anomalies in the standard model and ignoring any change in the data available. I don't see how the denialists have done anything other than pathological science (i.e., all normal science is wrong, and we will ignore any improvement or extension of their data).
Stewart

Stewart may be fashionably late to the party, yes, but I notice he places his hat at a jaunty angle, confidently strides into the room, sees the denialists huddled in a dark corner and then declares them unsocialized and maladapted wankers.

Welcome, Stewart. The bar is over there and there's a rack of my homebrew behind the bar - 9.0% and hoppy in front with a chocolate finish.

Best,

D

Thanks, Dano:
I brought a couple bottles of homebrewed pale ale as well, and a few bottles of our local brew 9Wild Rose Industrial Park Ale - nice beer mats, too).
I think that methodological fetishism is probably a useful wanker identification tool.
Stewart

...and I'm sure you noticed, Stewart, that there aren't any women huddling in that dark corner?

There's someone I want you to meet, BTW, she was asking about your hat...

D

""I'm not saying that at all. I'm saying that some of the proxy values in the twentieth century are higher (at the warm end) than most of the past proxy values over periods of say, 50 years."
And some of them aren't."

No kidding.

"you cannot guarantee linearity"

No kidding again. The point I keep trying to make is that non-linearity can only affect a small fraction of proxy values as long as it doesn't affect observed proxy values in the twentieth century.

"In fact, there has been a decline in tree ring growth of some supposedly "temperature sensitive" sites in the late 20th century which has been the cause of much discussion"

at McIntyre's blog? Dendroclimatologists have been dealing with these issues for a long time and one of the requirements (among many) for a multiproxy reconstruction is that each individual proxy has to sufficiently correlate with a local temperature record and have sufficient linearity. Is there anywhere in the scientific literature that discusses the effect of non-linearity on particular multi-proxy reconstructions (this doesn't include McIntyre's blog BTW).

" The straw man about Sargasso that you have posted up is unbelievable."

because you still didn't get the point.

"one of the examples I gave "isn't appropriate""

One of the examples showed that you missed the point.

" even though the others could be"

The others were relevant to the issue of non-linearity affecting annually-resolved proxies which is the issue I was dealing with. I wasn't trying to make any point about non-linearity affecting low resolution proxies. There are plenty of reconstructions that only use annually-resolved proxies to make the low resolution ones of lesser importance. BTW, speaking of low resolution proxies, how is McIntyre going with his demolition of Moberg's reconstruction?

" if the high frequency data differed from the low frequency data"

Generally speaking, no-one is suggesting that the data is free of noise.

"Also, you suggest MBH seeks high bandwidth data to pick out individual warm years; if it was capable of doing this, it would have a halfway decent cross-validation r^2."

What's the definition of halfway decent cross-validation r^2?

" your observation that these (proxies) appear not to be present in the B&C paper begs the question: why not? Was the sample selection in MBH biased?"

What observation was that?

""In any case B&C's issue was about linear extrapolation error which is clearly a problem at the cold end"
B&C raised more than one issue. They mention both linear extrapolation problems (clearly a problem at both ends"

thank you for your opinion,

"when you select an unbiased set of proxies) as well as the possibility of non-linearity."

They mention non-linearity (again at the cold end) but their detailed discussion was on linear extrapolation error. The issue of extrapolation error would affect local reconstructions as well as multiproxy reconstructions so I would expect this issue should have been considered in the past in connection with local reconstructions and thus creators of multi-proxy reconstructions should be aware of it. BTW, B,F&C in their Tellus paper say "the calibrating 20th century climate is much warmer than the rest of the millennium."

" "So in these circumstances the response is not likely to be near an inverted U."
Only if you assume previous temperatures are close to the temperatures in the calibration interval,"

No this doesn't assume they are close, not near also means not close.

" Given that some of these sites are not reflecting the recent 20th century warmth"

How many of these sites are used in multi-proxy reconstructions and how much influence do they have on reconstructions? Also, if you have proxies that indicate warmer temperatures in the past then these have a good chance of not turning down at temperatures higher than the present so could be useful in reconstruction.

" "BTW, McIntyre says elsewhere "If the bristlecones are excluded from the network and principal components are calculated without the bristlecones, there is no hockey stick shape." "
Yes, that conclusion is based on his own runs using his own emulation of MBH98, so it stands on its own.

Oh so now it is just bristlecones that are excluded and you're giving up on the idea that McIntyre actually meant it was more than just bristlecones that were excluded. The above quote came from one of McIntyre's articles were he was talking about the contents of MBH's BACKTO_1400-CENSORED directory. He was not talking about his own emulation. So my original point stands that McIntyre originated incorrect information such as the idea that the data in the ftp://holocene.evsc.virginia.edu/pub/MBH98/TREE/ITRDB/NOAMER/BACKTO_140… directory only has bristlecone pine proxies removed when it actually has the entire North American tree ring data set and Queen Anne data set removed.

" "Removing 70% of all the proxy data has an adverse effect. Gee that's a surprise."
MBH claimed in their paper that the NH reconstruction was robust to the removal of all dendroclimatic indicators."

Before we find out if you're playing with grammatical errors, exactly where did they say this?

I'll say in conclusion that all this wondering about details of dendroclimatology that McIntyre and other amateurs who read his blog do, should motivate them to read a few papers on the subject other than the ones McIntyre picks out for them. If they did they might get some idea of the amount of detail that has already been considered by professionals in the field.

Chris, chris, chris.

You are presuming that the personality type with a self-identity that finds the words on CA appealing will read primary sources.

Best,

D

Chris:

Thank you for your last post. You corrected a misconception I had about MBH98. I have heard the skeptics say it so many times that I thought the paper said that the results were robust to the exclusion of the dendroclimatic indicators.

So I went to the paper and had another read. From the paper:

In short, the inclusion of the proxy data in the ?multiproxy?
network is essential for the most skilful reconstructions. But
certain sub-components of the proxy dataset (for example, the
dendroclimatic indicators) appear to be especially important in
resolving the large-scale temperature patterns, with notable
decreases in the scores reported for the proxy data set if all
dendroclimatic indicators are withheld from the multiproxy network.
On the other hand, the long-term trend in NH is relatively
robust to the inclusion of dendroclimatic indicators in the network,
suggesting that potential tree growth trend biases are not influential
in the multiproxy climate reconstructions.

This only goes to show that Mr. Dano is correct with his thought that amateurs should be careful when reading technical papers.

WRT John Cross' latest, MBH 99 has more on this issue.

Your last para., John, just goes to show why the women at Stewart's party don't go for the corner-huddling denialist-type with the Cheeto-stained boxers.

See, women can tell when people make sh*t up.

Best,

D

Hmm. Seems people are confusing the term "not as good" with "robust". These are two separate aspects of a statistical system that mean different things. Let's temporarily move away from MBH98 to explain the difference, in simple to understand terms.

Let's consider a simple system. We have 100 noisy measurements of a data point, each measurement being an independent normally distributed measurement with standard deviation of 1. If I average those data, I get a refined version of the measurement - the standard deviation drops with the square root of the number of samples, so my new measurement based on the average has an standard deviation of 0.1. Let us say (for instance), the result comes out to be -0.56.

Now let's say we are concerned half of those measurements come from a particular source that may contain bias. We can eliminate those measurements and see what happens. In an unbiased system, by only averaging 50 samples, the standard deviation increases from 0.1 to 0.14. So, yes, our new measurement is worse, but only by a small amount. Furthermore, our samples are correlated, so we would expect the new measurement to be close to the original one; but "not as good".

If by removing those samples, our result shifts from -0.56 to -0.48, it shows the result is robust. The statistics of the system are well behaved, and the -0.56 value should be more accurate.

If by removing those samples, our result suddenly shifts from -0.56 to +0.63, we know we have a serious problem. That is a far larger swing than a well-behaved statistical system should allow. This shows a lack of robustness. On this basis, we cannot trust the -0.56 as it is far more sensitive to small changes in the data than it should be.

The problem either lies with the data or the method. In the example above, we can quite quickly eliminate the method - a simple average is easy to understand - and question the underlying data, or the assumptions implicit in the data.

So, having clarified the difference between "not as good" and "not robust", let's go back to MBH98. From the paper, and John Cross' quote,

"But certain sub-components of the proxy dataset (for example, the dendroclimatic indicators) appear to be especially important in resolving the large-scale temperature patterns, with notable decreases in the scores reported for the proxy data set if all dendroclimatic indicators are withheld from the multiproxy network."

OK, what he is saying here, is if you leave out the dendro samples the verification of the networks (in the late 19th century) becomes worse, i.e. the results are "not as good", which is what we would expect. But then the next sentence addresses a different issue:

"On the other hand, the long-term trend in NH is relatively robust to the inclusion of dendroclimatic indicators in the network, suggesting that potential tree growth trend biases are not influential in the multiproxy climate reconstructions."

Now, we can't verify what happened in the 15th century because we don't have instrumental records going back that far, so we can't truly determine if the 15th century is "not as good". But we can check that the statistics are well-behaved, and this is what this sentence refers to. Mann claims that the long-term trend in NH temperature (which dominates the global mean temperature, and contains the bristlecone pines) is robust, i.e. doesn't suddenly swing when removing some parts of the data.

Yet, we know this simply isn't true. The 15th century data (i.e. the long term trend) swings by the amount of the entire reconstruction when eliminating the dendroclimatic indicators - or even just the bristlecone pines.

So yes, Mann does claim that the reconstruction is robust to the inclusion or exclusion of the dendroclimatic indicators. But this point has been clearly falsified by McIntyre. To understand this point, you have to understand the differences between "robust" and "not as good" in the context of a statistical system. Mann knows the difference, which is why he realised the importance of making the claim in his study. It appears very few people here understand the important statistical differences between being not as good, and lacking robustness. I suppose this was pretty clear from some of the naive commentary on Burger and Cubasch's results above, attempting to interpret B&C's graphs as "temperature".

In my simple example above, we could eliminate the method as being a simple average. We cannot do this for MBH98 because of the complex methodology used by Mann. All we know - demonstrated by McIntyre, Burger and Cubasch - is that either the data, or the method, or both, is flawed in MBH98, as the results lack robustness.

While I'm here, it would be worth pointing out that I wasn't aware of the full details of what was left out in the CENSORED directory, and simply took Chris' claim at face value. It seems Chris' claim was a distortion of the truth. That's a little disappointing, but not entirely surprising.

"This only goes to show that Mr. Dano is correct with his thought that amateurs should be careful when reading technical papers."

I agree John; as an amateur, you should take care when reading such papers. You've misunderstood an important statistical point.

Spence:

I agree John; as an amateur, you should take care when reading such papers. You've misunderstood an important statistical point.

You wound me deeply! Well, actually not - since I am not a statistican. My intrepertation was based on what I read. You equate "long-term trend" with "reconstruction" and I do not do so.

I would intrepert the comment as saying if you remove the dendrochronology (leaving you the corals and the ice cores) these would then show a general trend up as we get towards the present.

Regards,
John

Wow, S_UK really has a lot invested in quibbling about an old, first paper, eh?

Has someone chosen an identity that is dependent upon something being not true?

Best,

D

John,

Of course we have to judge what Mann meant from his words, and who knows he might have meant what you are saying, but it doesn't particularly read like that. The late 19th century and 20th century are covered by the cross-validation and calibration statistics respectively (which effectively covers the "blade" of the hockey stick). The first sentence is referring to this period (because it refers to the scores). The "long term trend" is referred to in contrast to the previous sentence ("on the other hand"), and is a cruder test of robustness (since it is not possible to verify the earlier temperatures any other way), so I read it as referring to the "shaft" of the hockey stick, i.e. 15th century through to the 18th century.

Dano,

I originally tried to push the discussion down the route of the NAS panel and the wider issues of multi-proxy studies (such as those raised by Burger and Cubasch 2005, which raises a common problem across most papers even though it uses MBH98 as an example), but John and Chris have steered the discussion very much to McIntyre and MBH98. But I note you blame me for this. The irony is not lost on me.

There is an old joke that is appropriate in this situation. Well, I use the word joke in it's loosest possible terms, but it is apt.

A fly-on-the-wall documentary team interview the mother of a small family, asking her how decisions are made in her household. "Well", she says, "I make all the small, detail decisions for the household; my husband makes all the big decisions". When asked to give an example of the decisions she makes, she says "I decide things like where we live, what schools the children go to, things like that."

The interviewer, taken aback by this description of "small" decisions, asks what sort of decisions the husband makes. "Oh", she says. "He makes decisions like, who should be the next President, or whether we should go to war with another country"

So there we have it. Dano, you go ahead and answer the big questions of the day. I'll stick to the small ones.

...John and Chris have steered the discussion very much to McIntyre and MBH98. But I note you blame me for this. The irony is not lost on me.

My sincere apologies, Spence, for not rereading this 100-some comment thread to keep what has transpired at the fore of my awareness. I do hope you have some forgiveness in your heart and I'll try to do less throughout the day so I can follow along more better-like.

But, I must say, re-scanning this thread to avoid further mistakes, though, suuure is interesting.

I see that the argumentation upthread uses stuff that is pre-chewed for folk from only one source. The paleo/dendro community, apparently - even though they do this for a living - doesn't move as fast as someone who does not do dendro for a living (or ever).

Odd how that works, no?

In the meantime, the decision-making community doesn't read that one website that complains it can't get traction (maybe it's the amen chorus, or the cheer squad, or the periodic attacks or something, but hey).

The decision-making community, see, doesn't have time for small questions, Spence, so they get good counsel from folk who look all over the place (not just in one place, see) and make decisions.

Too bad for the contrascientists, folks with oddly-chosen identities and anti-science ideologues that no one looks to one website for counsel, huh?

Yup. Toooo bad.

Best,

D

Dano,

Good of you to admit you didn't bother reading the thread. So your primary contribution to this discussion, is to drift on, not really follow what is being talked about, declare anyone who disagrees with you as being a wanker, and criticise people's oddly-chosen identities. Am I right in assuming that is what you call "science", and my discussion is "anti-science"? I also note your willingness to cheerlead Realclimate yet you get upset about it when it happens on other blogs. I wonder how you square that circle?

My arguments specific to MBH come from 3 sources, yes McIntyre is one of them, also von Storch and Burger and Cubasch. My arguments about good scientific and statistical practice date back long before multi-proxy temperature reconstructions were a glint in their author's eyes.

Your link to the "decision-making community" - Seattle no less - is laughable. I can find a politician who will swear blind black is white if it helps his cause. That's why I avoid politics and stick to the science.

As for people "from the outside" knowing more than those "on the inside", from my work with statistics, it doesn't surprise me. Often people stuck in one community are just too close to the coal face to see what they are doing wrong, and it takes an outsider to wake them up to this fact. Which is one of the reasons I like to occasionally look at debates in fields outside my own. The Torah codes was a very interesting statistical debate, and I could draw parallels between that and some of the errors made in the multi-proxy studies. Interestingly, that concept was finally falsified when both sides of the argument got together, agreed a proper sampling protocol and failed to replicate the statistical significance claimed. The lack of a proper study protocol in the multi-proxy studies prevents this kind of a test. That type of statistical malpractice makes a statistician suspicious.

BTW, your extensive use of the prejudicial language logical fallacy continues to amuse. Keep up the good work.

Spence: I put up with your snide comment that I misunderstood an important statistical point..

But I can not fathom why you made this comment: but John and Chris have steered the discussion very much to McIntyre and MBH98.

If you please re-read the thread you will find that I do bring up McIntyre in a discussion with Dennis Williams in regards to a claim about Mr. McIntyre being funded by industry (as a side note I don't think he is and I don't really care if he is, but even you have to admit the irony of making a statement that you are not willing to back up).

However let me outline my discussion with you:

-->We started discussing the composition of the NAS panel. I discussed Cuffey's work and Christy's contribution.
-->Out next conversation started with a statement by yours about misunderstanding McIntyre's point to which I did respond.
-->My next comment was again a response to yours where you brought up M&M, vS and B&C.
-->My next comments were about the Sargasso Sea (not a proxy of MBH98 and nothing to do with McIntyre) and contained a statement that we should move on which you did not apparently agree with since you said "The points you (and Dano) subsequently raise are to do with the wider issue of global warming, which is really an entirely different debate to that of historical temperature reconstruction (IMHO)."
--> I did respond to a post by Chris about how Mann used robust in the paper since the phrase I had always heard was "robust to the presence or absence of ..." and I had accepted it without question. I am willing to admit I was wrong in this respect.
-->You then attacked me again and brought the discussion back to McIntyre.

Now, I request that you back up your statement and point out where I have "steered the discussion very much to McIntyre and MBH98". Absent that I expect to receive a retraction!!!

Good of you to admit you didn't bother reading the thread. So your primary contribution to this discussion, is to drift on, not really follow what is being talked about, declare anyone who disagrees with you as being a wanker, and criticise people's oddly-chosen identities.

As you can see, S_UK, my comments are throughout, so I have read the thread. What I did not do was find it important enough to remember.

Am I right in assuming that is what you call "science", and my discussion is "anti-science"?

That's quite a stretch.

I can find a politician who will swear blind black is white if it helps his cause. That's why I avoid politics and stick to the science.

The decision-makers are acting on the science. Good on you to stick to the science, which is good enough to act on!

Best,

D

The earth is warming. Ecosystems are changing at rates not seen before according to our current understanding. This is not in dispute...

The earth and life are infinitely complex. So much so that noone can understand how they were created. Therefore there must be a creator being called God. This is not in dispute.

I can pretty much say whatever I want after that.

Saying, "These are facts, accept them, they are not in dispute," is no different than an evangelist preaching from the pulpit. I should know, I dealt with such people while growing up.

Science is different, it questions everything, including itself.

John: let's be clear here. My remark about you being an amateur misunderstanding a statistical point was a parody of the fact that you made the same sort of statement. If you feel put out at being labelled with that statement, perhaps you shouldn't have used it in the first place.

Looking back down the thread, our first discussion was regarding the NAS panel (on topic! shock!!!). My second comment was to do with a misrepresentation raised by Chris about the M&M paper, in which I tried to broaden the discussion outside of just M&M (by including B&C, etc). Looking down the thread I would agree that we continued to discuss wider issues, while Chris continued to raise new points specific to the M&M vs. MBH98 debate.

So I retract my earlier statement, and amend it to stress to Dano that whilst John and I were generally discussing the broader issue of multi-proxy studies, Chris was very much narrowing the debate to MBH98 vs. M&M.

While I'm at it, I'd like to stress that I have no issue with narrowing the debate to M&M vs. MBH98, or broadening it to the wider issue of multi-proxy studies: there is nothing wrong with either of those approaches. I'm just bemused as to why Dano is trying to dress the former up as a bad thing and label me with it, when it clearly takes two to tango. I guess he only has petty arguments left to respond with, although I'm almost descending to his level by offering a reply.

As you can see, S_UK, my comments are throughout, so I have read the thread. What I did not do was find it important enough to remember.
Posting comments to a thread does not require reading the thread. If it isn't important enough to remember why do you feel the need to comment? It would seem to me your apparent disinterested status is greatly exaggerated.

That's quite a stretch.
Mental note to self: Dano is incapable of detecting irony. Are you American? That would explain a lot.

Jeremy, if you have some facts and empirical findings that show something other than what I said, bring them.

Otherwise, according to our understanding what I said is not in dispute. See, just because somebody doesn't like a finding doesn't mean its in dispute.

Your sloppy argumentation does nothing to change this fact. It's great that you can say science questions stuff, but typing all those wurdz does nothing to refute what I said.

===========

S_UK:

If you flap your arms hard enough, you can fly. That's what I hear, anyways.

They also tell me that too much hand-waving leads to Carpal Tunnel Syndrome. With plentiful evidence already pointing towards wankery, one might suggest that you be careful of your right wrist, if you get my drift.

Best,

D

If you flap your arms hard enough, you can fly. With plentiful evidence already pointing towards wankery [snip]
Darn you Mr Dano, with your cunning scientific logic and reasoning. I got no answer to that one.

"the data in the ftp://holocene.evsc.virginia.edu/pub/MBH98/TREE/ITRDB/NOAMER/BACKTO_140… directory only has bristlecone pine proxies removed when it actually has the entire North American tree ring data set and Queen Anne data set removed"

I made this statement in the mistaken belief that this was the source of McIntyre's misinformation that just leaving out the bristlecone pine proxies makes a substantial difference to MBH98's reconstruction. I have found out that McIntyre used data from the above directory, apparently without any statement about what Mann's actual use of that data was, for his own clearly flawed reconstruction process to produce a different result from MBH98 and thus try to claim that this proves that MBH98 is not robust to leaving out bristlecone pine proxies. As Mann points out in this interview, MBH "performed a set of sensitivity tests to determine if a skillful reconstruction was available without correcting certain high-elevation tree-ring chronologies", i.e. the bristlecone pine proxies, "for sensitivity to possible non-climatic (e.g. co2-fertilization) effects. These calculations were performed as part of these analyses, after MBH98. This is all discussed quite clearly in our follow-up paper to MBH98 published in the journal GRL in 1999" (MBH99).

So Mann was quite aware of the possible non-climatic effects on the bristlecone pine proxies and presumably the absence of these proxies in the BACKTO_1400-CENSORED directory means he was doing some sort of robustness test involving these proxies. So Mann certainly gave these proxies some robustness testing.

Mann also points out "It is sad that McIntyre and McKitrick have been reduced to scouring our website for things like this, to take out of context, and make false and misleading assertions."

Lets be clear here Chris: you made this mistake in an unprincipled attempt to defend MBH98.

The Mann method of reconstruction - whether you include the dubious CO2 fertilisation correction Mann applies in MBH99 or not (which Mann's best attempt to justify to date involves telling people to look at google scholar - classy) - is not robust to the presence of the bristlecone pines, representing less than 10% of the MBH98 data set, as shown by M&M.

It is not robust to a posterior selections in the regression step, as shown in B&C.

These can be trivially proven, by yourself, by downloading R code either from the ClimateAudit site or Ammann and Wahl (the two pieces of software agree to machine accuracy, so it really doesn't matter which) and applying the test (note: you have to set this test up with the W&A code, they are rather selective as to which tests they provide input data to run).

The "reconstruction" fails significance against r^2 cross-validation (ref. W&A) and fails significance against properly computed RE statistics (ref. M&M reply to Huybers, the last word on this subject in the scientific literature)

Bottom line: neither MBH98 or MBH99 are robust to a large number of changes (important note: "not robust" and "not as good" do not mean the same thing - see my note above).

Whether or not Mann knew about the problems is just a sideshow IMHO. The "reconstruction" is junk for more than one reason, I personally have no interest in whether Mann knew about this at the time or not (others may feel differently), let's just accept more work is needed in the area and move on.

"Lets be clear here Chris: you made this mistake in an unprincipled attempt to defend MBH98."

unprincipled. Thank you for your opinion. I'll admit that McIntyre can be pretty confusing to a non-expert. Especially when he gives an article a particular title and says he is going to show something relevant to that title and then without skipping a beat changes the issue. I can see that relying on McIntyre to stick to the issue (as a non-expert needs) is not a wise choice. Let me point out something else Mann said:

"This claim by MM is just another in a series of disingenuous (off the record: plainly dishonest) allegations by them about our work."

It is staggeringly hypocritical for someone supporting McIntyre's arguments to accuse others of lacking principle.

"The Mann method of reconstruction is not robust to the presence of the bristlecone pines, representing less than 10% of the MBH98 data set, as shown by M&M."

Sure, just like they showed it was not robust to changing the principle components analysis centring choice.

"It is not robust to a posterior selections in the regression step, as shown in B&C."

We'll have to wait to see what the experts say about B&C's work.

"These can be trivially proven, by yourself, by downloading R code either from the ClimateAudit site or Ammann and Wahl (the two pieces of software agree to machine accuracy, so it really doesn't matter which) and applying the test (note: you have to set this test up with the W&A code, they are rather selective as to which tests they provide input data to run)."

The W&A emulation, that I'm aware of, of MM05's E&E method using the MBH 1450 proxy network produces a reconstruction without the bristlecone proxies that passes validation and is robust to the absence of the bristlecone proxies. So there's no problem going back to 1450. That hockeystick is there from 1450 with or without bristlecone proxies. Their emulation of MM05's E&E method using the MBH 1400 proxy network produces a reconstruction without the bristlecone proxies that fails validation while if the bristlecone proxies are included it passes validation. So I guess robustness in this case means the temperature reconstruction passes validation against the instrument record or more recent proxies in spite of part of the proxies having growth trends that are not related to the instrument record or other proxies.

"The "reconstruction" fails significance against r^2 cross-validation (ref. W&A)"

We know that's vitally important to McIntyre.

"and fails significance against properly computed RE statistics (ref. M&M reply to Huybers, the last word on this subject in the scientific literature)"

M&M's reply is the last word. Sure.

Wow.

You use a quote from Mann that describes M&M as being "dishonest" (off-the-record, in a letter, whatever the hell that means) without any supporting evidence, and you suggest McIntyre is the unprincipled one? Now that is funny.

As for "non-expert", I have considerable experience in statistics and statistical issues. Whilst I recognise I have little expertise in paleoclimatology, the issues that I have raised are primarily statistical issues, on which I am quite capable of understanding and responding to. I have seen little evidence that your statistical skills are up to understanding the substantive issues (e.g. your failure to understand the differences between "not as good" and "not robust").

Many of my arguments come from the scientific literature, apart from one or two things from W&A, most of yours seem to come from stuff Mann and co have posted on blogs.

"Sure, just like they showed it was not robust to changing the principle components analysis centring choice."

I see you don't have a real answer to that, but ironic mockery of the point probably helps make it seem less real in your own mind, at any rate.

"We'll have to wait to see what the experts say about B&C's work."

B&C are experts, and the work is in the scientific literature, which means it has passed peer review by "experts" of some description. That isn't to say it won't be found to be flawed, or superseded in the future. That's the way science works. But at the moment it is "current".

"The W&A emulation, that I'm aware of, of MM05's E&E method using the MBH 1450 proxy network produces a reconstruction without the bristlecone proxies that passes validation and is robust to the absence of the bristlecone proxies."

Hmmm, you still haven't figured out this lack of robustness in a statistical study have you? If person A shows a method or data lacks robustness through demonstration, picking cases that appear to be robust cannot falsify the observed lack of robustness. It doesn't make the problem cases go away. W&A selectively running cases that give similar results adds nothing. They judiciously avoided the M&M cases that shows no robustness. It is obvious just looking at their website how selective they were in what they ran. That is why I said above you have to set up your own input files with W&A. The W&A emulation is mathematically and algorithmically identical to the M&M emulation, which is why it gives the same answer. (You can check this easily yourself by downloading the code and running it). None of the emulations pass a true test of statistical skill, including MBH or W&A (unless you can provide me the reference below).

""and fails significance against properly computed RE statistics (ref. M&M reply to Huybers, the last word on this subject in the scientific literature)""

"M&M's reply is the last word. Sure."

If you think someone else has set an RE benchmark for Mann's work after McIntyre's reply to Huybers in the scientific literature, please point me to the reference, and I'll back down on this. W&A set no benchmark in CC, they rely on their GRL article which (as we know) did not pass peer review.

"You use a quote from Mann that describes M&M as being "dishonest" without any supporting evidence"

Refer to what Mann said,

"As for "non-expert""

I was referring to myself as a non-expert who was reliant to a degree on McIntyre making a straight argument which he doesn't always do.

"B&C are experts"

I said the experts, which doesn't mean just two of them.

"But at the moment it is "current".

Whatever "current" means. Could that be "awaiting confirmation"?

""The W&A emulation, that I'm aware of, of MM05's E&E method using the MBH 1450 proxy network produces a reconstruction without the bristlecone proxies that passes validation and is robust to the absence of the bristlecone proxies."
Hmmm, you still haven't figured out this lack of robustness in a statistical study have you?"

You don't seem to be getting the point here. The issue is robustness to whether bristlecone proxies are included or excluded. W&A showed that it is robust to including or excluding bristlecone proxies from the 1450 proxy network. McIntyre's issue is that the reconstruction doesn't work without bristlecone proxies (which is true before 1450) and that somehow these bristlecone proxies produce an incorrect result.

" picking cases that appear to be robust cannot falsify the observed lack of robustness"

You seem to have the idea that these proxies are all just independent random variables with the same mean etc. Well they're not. They're correlated so that when the number of proxies available drops quite low (such as before 1450), leaving out one set can have quite a large effect on the result. There is a very non-linear relationship between proxy numbers and accuracy of results. I haven't looked up what the number of proxy sets for MBH 1400 to 1450 is but at 1000 in MBH99 it is seven in the northern hemisphere.

"None of the emulations pass a true test of statistical skill, including MBH or W&A"

Yes McIntyre thinks he has a true test of statistical skill, considering that in his rejected comment to Nature he incorrectly calculated all of his verification statistics.

""and fails significance against properly computed RE statistics (ref. M&M reply to Huybers, the last word on this subject in the scientific literature)""
"M&M's reply is the last word. Sure."

I was taking "the last word" in the sense that there will never be another word said about it. "the latest word" would have been more accurate. The status is that M&M disagree with W&A's view on RE statistics. W&A say they have done work to show a different view but have not yet published it.

"W&A set no benchmark in CC, they rely on their GRL article which (as we know) did not pass peer review"

for reasons other than the material on RE statistics. Hopefully this material will be published very soon.

"Whatever "current" means. Could that be "awaiting confirmation"?"

In a Popperian sense, "valid until falsified" seems reasonable to me. Yes, it may be corrected or superceded, but until then it is the best available.

"for reasons other than the material on RE statistics."

No - for many reasons including the material on RE statistics. Steve explains this better on the thread noted below.

There seems little point in continuing this here since the same points are being discussed under this topic, including comments from Steve (who will put these things more accurately than I can). There seems little point in having the same debate twice in two places, so I'll suggest that the debate continues there [where it won't need me :-)].

""Whatever "current" means. Could that be "awaiting confirmation"?"

In a Popperian sense, "valid until falsified" seems reasonable to me. Yes, it may be corrected or superceded, but until then it is the best available."

So if someone publishes a paper like for example "Corrections to the Mann et al (1998) Proxy Data Base and Northern Hemisphere Average Temperature Series" by McIntyre and McKitrick then even though it is full of rubbish it becomes the best paper available until it is corrected or superceded simply because it's published. Sure.

""for reasons other than the material on RE statistics."

No - for many reasons including the material on RE statistics. Steve explains this better on the thread noted below."

Not that I noticed.

The previous message was mine. (In case anyone can't guess.)

Given that you guys have demonstrated your dispassionate, forthright, and determined commitment to objective and sound science, I would be interested to know what you think of this article.

http://libertyunbound.com/archive/2007_05/jason-warming.html

How do I respond to those who argue this viewpoint?

Also, while I am here, it is disappointing to see the dendroclimatologists allow a long and damaging discussion on tree/temperature relationships without careful and measured response.