The Wegman and North Reports for Newbies

In recent discussion of the Weblog 2007 Awards, several commenters at other blogs have argued that our criticisms of the Mannian parlor tricks have been “thoroughly refuted and discarded by climatologists, published in a credible journal”; that “other professionals in the field who also have “looked in great detail at the problem at hand” and have come to the conclusion that rather than McIntyre’s findings being “valid and relevant”, they instead have found them to be “without statistical and climatological merit”; that CA “fluffed on the whole hockey stick thing”. See for example here

Omitted in these references are the fact that the people described as “climatologists published in a credible journal” or “professionals in the field” are none other than Wahl and Ammann, serial coauthors with Michael Mann, students of Mann, who are not independent of the controversy. Indeed, they largely use (without citation or attribution or even acknowledgment to Michael Mann) arguments originally published at realclimate (and already responded to in MM 2005b(EE). Aside from their lack of independence, neither Ammann nor Wahl qualify as statistical authorities. Ammann did his undergraduate work in geology; Wahl in divinity. While this does not exclude them from having potential insight in the matter, it is evidence that one should not necessarily expect a sure grasp of mathematical and statistical issues and that their conclusions cannot be relied upon uncritically, even if Stephen Schneider accepted their article.

Readers interested in a third party view of the matter are far better off consulting the North Report, the Wegman report, (particularly) Wegman’s Reply to Questions and Richard Smith’s account of the 2006 American Statistical Association session. All of these individuals are vastly more eminent than Ammann and Wahl. Wegman, in particular, has been Chair of the National Academy of Sciences Committee on Theoretical and Applied Statistics and is a legitimate statistical expert. His comments on the Wahl and Ammann preprint are very acute and have not received appropriate consideration.

I’ve collated some of these remarks for the benefit of new readers who haven’t been following this particular story. Please read the comments below using the analogy from the previous post: see if any of our criticisms of Mannian parlor tricks have been refuted – as opposed to whether someone arguing that you can re-tool the trick to still saw the woman in half a different way. (And for this latter, pay particular attention to Wegman’s comments on Wahl and Ammann later in the post.)

The Wegman Report

The original Wegman Report is online here. Here are some excerpts from this report:

The debate over Dr. Mann’s principal components methodology has been going on for nearly three years. When we got involved, there was no evidence that a single issue was resolved or even nearing resolution. Dr. Mann’s RealClimate.org website said that all of the Mr. McIntyre and Dr. McKitrick claims had been ‘discredited’. UCAR had issued a news release saying that all their claims were ‘unfounded’. Mr. McIntyre replied on the ClimateAudit.org website. The climate science community seemed unable to either refute McIntyre’s claims or accept them. The situation was ripe for a third-party review of the types that we and Dr. North’s NRC panel have done.

While the work of Michael Mann and colleagues presents what appears to be compelling evidence of global temperature change, the criticisms of McIntyre and McKitrick, as well as those of other authors mentioned are indeed valid.

“Where we have commonality, I believe our report and the [NAS] panel essentially agree. We believe that our discussion together with the discussion from the NRC report should take the ‘centering’ issue off the table. [Mann's] decentred methodology is simply incorrect mathematics …. I am baffled by the claim that the incorrect method doesn’t matter because the answer is correct anyway.
Method Wrong + Answer Correct = Bad Science.

The papers of Mann et al. in themselves are written in a confusing manner, making it difficult for the reader to discern the actual methodology and what uncertainty is actually associated with these reconstructions.

It is not clear that Dr. Mann and his associates even realized that their methodology was faulty at the time of writing the [Mann] paper.

We found MBH98 and MBH99 to be somewhat obscure and incomplete and the criticisms of MM03/05a/05b to be valid and compelling.

Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

[The] fact that their paper fit some policy agendas has greatly enhanced their paper’s visibility… The ‘hockey stick’ reconstruction of temperature graphic dramatically illustrated the global warming issue and was adopted by the IPCC and many governments as the poster graphic. The graphics’ prominence together with the fact that it is based on incorrect use of [principal components analysis] puts Dr. Mann and his co-authors in a difficult face-saving position.

We have been to Michael Mann’s University of Virginia website and downloaded the materials there. Unfortunately, we did not find adequate material to reproduce the MBH98 materials. We have been able to reproduce the results of McIntyre and McKitrick

Generally speaking, the paleoclimatology community has not recognized the validity of the [McIntyre and McKitrick] papers and has tended dismiss their results as being developed by biased amateurs. The paleoclimatology community seems to be tightly coupled as indicated by our social network analysis, has rallied around the [Mann] position, and has issued an extensive series of alternative assessments most of which appear to support the conclusions of MBH98/99… Our findings from this analysis suggest that authors in the area of paleoclimate studies are closely connected and thus ‘independent studies’ may not be as independent as they might appear on the surface.

It is important to note the isolation of the paleoclimate community; even though they rely heavily on statistical methods they do not seem to be interacting with the statistical community. Additionally, we judge that the sharing of research materials, data and results was haphazardly and grudgingly done. In this case we judge that there was too much reliance on peer review, which was not necessarily independent.

Based on the literature we have reviewed, there is no overarching consensus on [Mann's work]. As analyzed in our social network, there is a tightly knit group of individuals who passionately believe in their thesis. However, our perception is that this group has a self-reinforcing feedback mechanism and, moreover, the work has been sufficiently politicized that they can hardly reassess their public positions without losing credibility.

It is clear that many of the proxies are re-used in most of the papers. It is not surprising that the papers would obtain similar results and so cannot really claim to be independent verifications.”

Especially when massive amounts of public monies and human lives are at stake, academic work should have a more intense level of scrutiny and review. It is especially the case that authors of policy-related documents like the IPCC report, Climate Change 2001: The Scientific Basis, should not be the same people as those that constructed the academic papers.”

Wegman on Wahl and Ammann

Wegman’s Reply to Questions is a really excellent consideration of the efforts of Wahl and Ammann to re-tool Mann’s parlor trick and prove that the late 20th century was paranormal. I’ve given the entire question 10 and Wegman response as it is clear and concise. (Again the issue is the narrow one of whether Mann et al proved that the late 20th century was paranormal.) Stupak asked:

10. In the footnote of your report, you reference papers by Wahl and Ammann (2006) and Wahl et al. (2006) and note that they “are not to the point.” I understand that Wahl and Ammann actually examined, among other things, the problem of data decentering, the main focus of your report, and corrected the emulation of MBH98 by recentering the data.

a. Did you analyze this work by Wahl and Ammann prior to sending your final report to the Committee on Energy and Commerce? If so, why does your report not alert the reader that these researchers had conducted a reanalysis of the MBH98 that corrected the only statistical methodology error discussed in the “Finding” section of your report and that these researchers found that recentering the data did not significantly affect the results reported in the MBH98 paper?

To which, Wegman answered:

Ans: The Wahl and Ammann paper came to our attention relatively late in our deliberations, but was considered by us. Some immediate thoughts we had on Wahl and Ammann was that Dr. Mann lists himself as a Ph.D. coadvisor to Dr. Ammann on his resume. As I testified in the second hearing, the work of Dr. Ammann can hardly be thought to be an unbiased independent report. It would have been more convincing had this paper been written by a totally independent authority, but alas this is not the case. The Wahl and Ammann paper is largely an attempt to refute the criticisms of McIntyre and McKitrick (MM). The comment we made in our footnote about being “not to the point” refers to the fact that MM03 and MM05 were not attempting to portray themselves as doing a paleoclimate reconstruction, they not being paleoclimatologists themselves, but were merely pointing out the flaws in the MBH98 and MBH99 papers. There are several comments of interest in the Wahl and Ammann paper. They suggest three areas in which the MBH papers have been subject to scrutiny.

First, the MBH reconstruction has been examined in light of its agreement/lack of agreement with other long-term annual and combined high/low frequency reconstructions. Wahl and Ammann (2006, p.3 in the 24 February 2006 draft)

Their conclusion is:

“The comparison of the MBH reconstruction, derived from multi-proxy (particularly tree ring) data sources, with widespread bore-hole-based reconstructions is still at issue in the literature.” Wahl and Ammann (2006, p.4 in the 24 February 2006 draft)

In other words, the MBH reconstruction does not agree with other widely accepted methodologies for climate reconstruction. Bore hole methods measure a temperature gradient and calculate the diffusion of heat within the bore hole. This method does not have nearly the confounding variables as do tree ring proxies. The second area of scrutiny involves comparison with results from modeling efforts.

“Second a related area of scrutiny of the MBH reconstruction technique arises from an atmosphere-ocean general circulation model (AOGCM) study , which also examines the potential loss of amplitude [in the MWP] in the MBH method (and other proxy/instrumental reconstructions that calibrate by using least squares projections of the proxy vectors onto a single- or multi-dimensional surface determined by either the instrumental data or its [their] eigenvectors.” Wahl and Ammann (2006, p.4 in the 24 February 2006 draft)

Again the MBH reconstructions do not correlate well with the model based methods. Wahl and Amman (2006) offer the following explanation.

“However, a number of issues specific to the modeling situation could arise in this context, including: how realistically the AOGCM is able to reproduce the real world patterns of variability and how they respond to various forcings7; the magnitude of forcings and the sensitivity of the model that determine the magnitude of temperature fluctuations ; and the extent to which the model was sampled with the same richness of information that is contained in the proxy records (not only temperature records, but series that correlate well with the primary patterns of variability including, for example, precipitation in particular seasons.” Wahl and Ammann, (2006, p.5 in the 24 February 2006 draft)

This quotation has two interesting facets. First, it seems to call into question the very models that are predicting temperature increases based on CO2 forcings. If these models do not coincide with the MBH reconstructions, then which are we to believe? Second, the quotation implicitly admits what we have observed previously, namely that there are other covariates such as precipitation, which are not teased out in the temperature reconstructions. Thus, what are purported to be temperature reconstructions are contaminated with covariates that reflect temperature indirectly at best and not at all at worst. The third area of scrutiny involves the challenges made by MM.

“A third area of scrutiny has focused on the nature of the proxy data set utilized by MBH, along with the pre-processing algorithms used to enhance the climate signal-to-noise characteristics of the proxy data.” Wahl and Ammann, (2006, p.5 in the 24 February 2006 draft)

We submit that both the mathematical analysis in Appendix A of our report to Congress together with our simulation demonstrate that the decentering method yields incorrect results. The critical issue then becomes the proxies themselves, which MM have challenged. A telling comment from Wahl and Ammann is the following.

“A further aspect of this critique is that the single-bladed hockey stick shape in proxy PC summaries for North America is carried disproportionately by a relative small subset (15) of proxy records derived from bristlecone/foxtail pines in the western United States, which the authors [MM] mention as being subject to question in the literature as local/regional temperature proxies after approximately 1850 . It is important to note in this context that because they employ an eigenvector-based CFR technique, MBH do not claim that all proxies used in their reconstruction are closely related to local-site variations in surface temperature.” Wahl and Ammann, (2006, p.9 in the 24 February 2006 draft).

This together with the AOGCM quotation reinforces the notion that MBH are attempting to reconstruct temperature histories based on proxy data that are extremely problematic in terms of actually capturing temperature information directly. As we testified, it would seem that there is some substantial likelihood that the bristlecone/foxtail pines are CO2 fertilized and hence are reflecting not temperature at all but CO2 concentration. It is a circular argument to say increased CO2 concentrations are causing temperature increases when temperature increases are estimated by using proxies that are directly affected by increased CO2 concentrations.

It is our understanding that when using the same proxies as and the same methodology as MM, Wahl and Ammann essentially reproduce the MM curves. Thus, far from disproving the MM work, they reinforce the MM work. The debate then is over the proxies and the exact algorithms as it always has been.

The fact that Wahl and Ammann (2006) admit that the results of the MBH methodology does not coincide with the results of other methods such as borehole methods and atmospheric-ocean general circulation models and that Wahl and Ammann adjust the MBH methodology to include the PC4 bristlecone/foxtail pine effects are significant reasons we believe that the Wahl and Amman paper does not convincingly demonstrate the validity of the MBH methodology.

The next part of the Stupak question was:

b. Do you agree or disagree with Wahl and Ammann’s finding that the time period used to center the data does not significantly affect the results reported in the MBH98 paper? If you disagree, please state the basis for your disagreement.

Ans: We do disagree. The fundamental issue focuses on the North American Tree Ring proxy series, which Wahl and Ammann admit are problematic in carrying temperature data. In the original MBH decentered series, the hockey-stick shape emerged in the PC1 series because of reasons we have articulated in both our report and our testimony. In the original MBH papers, it was argued that this PC1 proxy was sufficient. We note the following from Wahl and Ammann.

“Thus, the number of PCs required to summarize the underlying proxy data changes depending on the approach chosen. Here we verify the impact of the choice of different numbers of PCs that are included in the climate reconstruction procedure. Systematic examination of the Gaspé-restricted reconstructions using 2-5 proxy PCs derived from MM-centered, but unstandardized data demonstrates changes in reconstruction as more PCs are added, indicating a significant change in information provided by the PC series. When two or three PCs are used, the resulting reconstructions (represented by scenario 5d, the pink (1400-1449) and green (1450-1499) curve in Fig. 3) are highly similar (supplemental information). As reported below, these reconstructions are functionally equivalent to reconstructions in which the bristlecone/foxtail pine records are directly excluded [emphasis added] (cf. pink/blue curve for scenarios 6a/b in Fig. 4).

When four or five PCs are used, the resulting reconstructions (represented by scenario 5c, within the thick blue range in Fig. 3) are virtually indistinguishable (supplemental information) and are very similar to scenario 5b.” Wahl and Ammann, (2006, p.31, 24 February 2006 draft)

Without attempting to describe the technical detail, the bottom line is that, in the MBH original, the hockey stick emerged in PC1 from the bristlecone/foxtail pines. If one centers the data properly the hockey stick does not emerge until PC4. Thus, a substantial change in strategy is required in the MBH reconstruction in order to achieve the hockey stick, a strategy which was specifically eschewed in MBH. In Wahl and Ammann’s own words, the centering does significantly affect the results.

In passing, the results cited here by Wahl and Ammann had already been discussed in MM 2005b (but Wahl and Ammann fail to acknowledge the earlier discussion and imply that their treatment is novel. Actually the approach originated in Mann’s 2004 response to our Nature submission.) The third part of the question was:

c. Dr. Gulledge included in his testimony a slide showing the graph of WA emulation of the MBH and MBH-corrected for decentering and the Gaspé tree-ring series. Were you aware of their reanalysis of MBH99 prior to the time you finalized your report? Do you agree or disagree with their reanalysis of MBH99? If you disagree, please state the basis for your disagreement.

To which Wegman answered (and note the bolded portion as well):

Ans: Yes, we were aware of the Wahl and Ammann simulation. We continue to disagree with the reanalysis for several reasons. Even granting the unbiasedness of the Wahl and Ammann study in favor of his advisor’s methodology and the fact that it is not a published refereed paper, the reconstructions mentioned by Dr. Gulledge, and illustrated in his testimony, fail to account for the effects of the bristlecone/foxtail pines.

Wahl and Ammann reject this criticism of MM based on the fact that if one adds enough principal components back into the proxy, one obtains the hockey stick shape again. This is precisely the point of contention. It is a point we made in our testimony and that Wahl and Ammann make as well. A cardinal rule of statistical inference is that the method of analysis must be decided before looking at the data. The rules and strategy of analysis cannot be changed in order to obtain the desired result. Such a strategy carries no statistical integrity and cannot be used as a basis for drawing sound inferential conclusions.

The NAS (North) Report
If North et al agreed with the Wegman findings, as they testified to the House Subcommittee under oath, how did this get expressed in the NAS panel report? My view, at the time, and it’s unchanged, was that their report was “schizophrenic”: they agreed with our specific criticisms of Mannian parlor tricks within the body of the report, while at the same time, reporting that there were other proofs that late 20th century climate was paranormal. Eduardo Zorita at the time characterized the NAS report as being as severe as could be contemplated under the circumstances:

in my opinion the Panel adopted the most critical position to MBH nowadays possible. I agree with you that it is in many parts ambivalent and some parts are inconsistent with others. It would have been unrealistic to expect a report with a summary stating that MBH98 and MBH99 were wrong (and therefore the IPC TAR had serious problems) when the Fourth Report is in the making. I was indeed surprised by the extensive and deep criticism of the MBH methodology in Chapters 9 and 11.

So is there any actual language in the NAS panel report that supports any suggestion that they had repudiated any of our published claims in respect to Mannian statistical methodology? In the quotes below, I’ve searched every reference in the report to McIntyre (or MM).

First, like Wegman, they specifically and categorically agree that Mann’s principal components methodology is biased towards mining for hockey-stick shaped series. This is not the only way of doing this parlor trick – Mannian principal components is a fancy way of performing the parlor trick of selecting HS-series from a universe of noise, but you can do this the old-fashioned way: just pick them ( a methodology adopted in subsequent and previous studies.) The NAS panel (STR Preprint, 86) has an extended discussion of Mann’s principal components error as follows:

Spurious Principal Components: McIntyre and McKitrick (2003) [actually McIntyre and McKitrick 2005a] demonstrated that under some conditions, the leading principal component can exhibit a spurious trendlike appearance, which could then lead to a spurious trend in the proxy-based reconstruction. To see how this can happen, suppose that instead of proxy climate data, one simply used a random sample of autocorrelated time series that did not contain a coherent signal. If these simulated proxies are standardized as anomalies with respect to a calibration period and used to form principal components, the first component tends to exhibit a trend, even though the proxies themselves have no common trend. Essentially, the first component tends to capture those proxies that, by chance, show different values between the calibration period and the remainder of the data. If this component is used by itself or in conjunction with a small number of unaffected components to perform reconstruction, the resulting temperature reconstruction may exhibit a trend, even though the individual proxies do not. Figure 9-2 shows the result of a simple simulation along the lines of McIntyre and McKitrick (2003) (the computer code appears in Appendix B)….

Principal components of sample data reflect the shape of the corresponding eigenvectors of the population covariance matrix. The first eigenvector of the covariance matrix for this simulation is the red curve in Figure 9-2, showing the precise form of the spurious trend that the principal component would introduce into the fitted model in this case. This exercise demonstrates that the baseline with respect to which anomalies are calculated can influence principal components in unanticipated ways. (STR Preprint, 86)

They comment approvingly on our criticisms on the inappropriate reliance on the RE statistic (and failed verification r2 statistic) and on non-robustness to bristlecones as follows:

A second area of criticism focuses on statistical validation and robustness. McIntyre and McKitrick (2003, 2005a,b) question the choice and application of statistical methods, notably principal component analysis; the metric used in the validation step of the reconstruction exercise; and the selection of proxies, especially the bristlecone pine data used in some of the original temperature reconstruction studies. These and other criticisms, explored briefly in the remainder of this chapter, raised concerns that led to new research and ongoing efforts to improve how surface temperature reconstructions are performed ….The more important aspect of this criticism is the issue of robustness with respect to the choice of proxies used in the reconstruction. For periods prior to the 16th century, the Mann et al. (1999) reconstruction that uses this particular principal component analysis technique is strongly dependent on data from the Great Basin region in the western United States. Such issues of robustness need to be taken into account in estimates of statistical uncertainties. STR Preprint,106-7)

and again:

Regarding metrics used in the validation step in the reconstruction exercise, two issues have been raised (McIntyre and McKitrick 2003, 2005a,b). One is that the choice of “significance level” for the reduction of error (RE) validation statistic is not appropriate. The other is that different statistics, specifically the coefficient of efficiency (CE) and the squared correlation (r2), should have been used (the various validation statistics are discussed in Chapter 9). Some of these criticisms are more relevant than others, but taken together, they are an important aspect of a more general finding of this committee, which is that uncertainties of the published reconstructions have been underestimated. Methods for evaluation of uncertainties are discussed in Chapter 9 [multiple stats recommended) (STR Preprint, 107)

Obviously none of these direct references to our work amount to anything like a repudiation. Quite the contrary. In every case where we were specifically mentioned, they agreed with our criticisms. In addition, they also made several specific findings on matters associated with our critique which, while not mentioning us (as perhaps they should have), supported the points with which we were associated. For example, they said that strip bark dendro chronologies should be “avoided” in temperature reconstructions:

While “strip-bark” samples should be avoided for temperature reconstructions, attention should also be paid to the confounding effects of anthropogenic nitrogen deposition (Vitousek et al. 1997), since the nutrient conditions of the soil determine wood growth response to increased atmospheric CO2 (Kostiainen et al. 2004). (STR Preprint, 50)

We had obviously criticized the failed verification r2, CE and other statistics in the MBH reconstruction, a result confirmed by Wahl and Ammann, despite their opposite characterization. The NAS panel saw throught this characterization and observed the failed CE statistic in MBH, initially observed in MM2005 (GRL) (although they didn’t rub salt in the wound by also observing the failed verification r2 statistic, which had been the more prominent issue.) They said:

Reconstructions that have poor validation statistics (i.e., low CE) will have correspondingly wide uncertainty bounds, and so can be seen to be unreliable in an objective way. Moreover, a CE statistic close to zero or negative suggests that the reconstruction is no better than the mean, and so its skill for time averages shorter than the validation period will be low. Some recent results reported in Table 1S of Wahl and Ammann (in press) indicate that their reconstruction, which uses the same procedure and full set of proxies used by Mann et al. (1999), gives CE values ranging from 0.103 to -0.215, depending on how far back in time the reconstruction is carried. STR Preprint, 91

Large-scale surface temperature reconstructions demonstrate very limited statistical skill (e.g., using the CE statistic) for proxy sets before the 19th century (Rutherford et al. 2005, Wahl and Ammann in press). STR 111

Also without noting that it was us that had made the point, they also observed the non-robustness of these temperature reconstructions to small subsets:

Temperature reconstructions for periods before about A.D. 1600 are based on proxies from a limited number of geographic regions, and some reconstructions are not robust with respect to the removal of proxy records from individual regions (see, e.g., Wahl and Ammann in press). Because the data are so limited, different large-scale reconstructions are sometimes based on the same datasets, and thus cannot be considered as completely independent. …

Published information, although limited, also suggests that these statistics are sensitive to the inclusion of small subsets of the data. Some of the more regionally focused reconstructions (D’Arrigo et al. 2006) have better demonstrated skill back to the 16th century or so, and possibly earlier. To improve the skill of reconstructions, more data need to be collected and possibly new assimilation methods developed. STR 111

So I would submit that there are no comments in the NAS Panel report that, in any way, refute, rebut or repudiate any claims from the McIntyre and McKitrick articles. This is not to say that they do not present their own spaghetti graph as supposed evidence for the paranormal. I’ve discussed defects with each of these other parlor tricks on various occasions as well and have observed the singular lack of due diligence by the NAS panel in investigating these supposed evidences of the paranormal. But for now, all I’m re-capping here is that the NAS panel did not rebut our claims with respect to the supposed Mannian evidence of the paranormal.

Did Wegman and North Disagree?
There’s obviously been a lot of spinning here, as Wegman’s language was much more forthright. The realclimate crowd have tried to marginalize the clear statements in Wegman.

At the July 19, 2006 House Energy and Commerce Subcommittee hearing, Barton asked North very precisely whether he disagreed with any Wegman’s findings and North (under oath) said no as follows:

CHAIRMAN BARTON. I understand that. It looks like my time is expired, so I want to ask one more question. Dr. North, do you dispute the conclusions or the methodology of Dr. Wegman’s report?
DR. NORTH. No, we don’t. We don’t disagree with their criticism. In fact, pretty much the same thing is said in our report. But again, just because the claims are made, doesn’t mean they are false.
CHAIRMAN BARTON. I understand that you can have the right conclusion and that it not be–
DR. NORTH. It happens all the time in science.
CHAIRMAN BARTON. Yes, and not be substantiated by what you purport to be the facts but have we established–we know that Dr. Wegman has said that Dr. Mann’s methodology is incorrect. Do you agree with that? I mean, it doesn’t mean Dr. Mann’s conclusions are wrong, but we can stipulate now that we have–and if you want to ask your statistician expert from North Carolina that Dr. Mann’s methodology cannot be documented and cannot be verified by independent review.
DR. NORTH. Do you mind if he speaks?
CHAIRMAN BARTON. Yes, if he would like to come to the microphone.
MR. BLOOMFIELD. Thank you. Yes, Peter Bloomfield. Our committee reviewed the methodology used by Dr. Mann and his coworkers and we felt that some of the choices they made were inappropriate. We had much the same misgivings about his work that was documented at much greater length by Dr. Wegman.

Given these explicit statements by NAS panel officials, let’s take a look at what Wegman said about Mann et al and exactly what North, Bloomfield, Wallace and the others were agreeing with.

At the 2006 ASA meeting NAS Panel member Mike Wallace was reported as saying:

In Mike’s view, the two reports were complementary, and to the extent that they overlapped, the conclusions were quite consistent.

American Statistical Association Newletter
Wegman’s presentation was also discussed in the American Statistical Association newsletter here. discussing a packed session “What is the Role of Statistics in Public Policy Debates about Climate Change?” at the 2006 ASA meeting discussing statistics and climate change, to which Wegman, Mike Wallace of the NAS panel and Smith himself spoke.

Smith observed:

At the core of the controversy is an incorrect use by Mann et al. of principal components (PCs).

Note that there is no nuance here – Smith agrees with Wegman that the Mann et al method was incorrect. He then considered the argument that the error doesn’t not “matter” together with Wegman’s rebuttal:

A number of other commentators have acknowledged the flaws in the Mann reconstruction but have argued that this does not matter because the answers have been verified by other analyses. Ed’s own response to that was given in the equation:

Method Wrong + Answer Correct = Bad Science.

In other words, the fact that the answer may have been correct does not justify the use of an incorrect method in the first place.

Both Wegman’s talk and Smith’s account of it correctly noted that the issues with Mann et al were not just principal components, observing almost but not quite accurately:

Ed also touched on some of the other controversies in Mann’s work. Some of the proxies had been criticized as inappropriate. For example, bristlecone pines are known to be CO2 fertilized, creating a possible confounding problem if they are used in temperature reconstructionA figure from Mann’s own website suggested that the medieval warm period reappeared if bristlecone pines were excluded from the reconstruction. Other studies had shown a “discomforting array of different results” in the reconstructions obtained with minor methodological variations.

As noted above, NAS panelist Wallace agreed that the NAS panel did not disagree with Wegman on common issues:

In Mike’s view, the two reports were complementary, and to the extent that they overlapped, the conclusions were quite consistent.

Smith observed:

while there is undoubtedly scope for statisticians to play a larger role in paleoclimate research, the large investment of time needed to become familiar with the scientific background is likely to deter most statisticians from entering this field… In the end, it’s important not to lose sight of the forest for the trees, where the “forest” refers to the totality of scientific evidence for global warming.

As to the last sentence, I agree that it’s important not to lose sight of the forest for the trees. As a reviewer for AR4, it was my position that, if the paleoclimate issues were not relevant to the policy issues, then the Paleoclimate (and the hockey stick discussion) should be deleted from AR4 so that people could focus on what were the “real” arguments. The IPCC “consensus” was presumably that the paleoclimate arguments remained important and that’s why the chapter remained, despite my suggestions that it be deleted.

References:
Wegman Report http://climateaudit.files.wordpress.com/2007/11/07142006_wegman_report.pdf
Wegman Reply to Questions http://www.uoguelph.ca/~rmckitri/research/StupakResponse.pdf
North (NAS Panel) Report http://books.nap.edu/openbook.php?isbn=0309102251
North and Wegman at the House Energy and Commerce Subcommittee hearing
Richard Smith url


217 Comments

  1. Gunnar
    Posted Nov 6, 2007 at 12:17 PM | Permalink | Reply

    It’s a good idea to set the record straight for newbies. It’s certainly convenient for folks like me, who haven’t been reading this blog for that long. On the one hand, there are a vast number of people who are intellectually honest, when armed with these indisputable facts, will come to the correct conclusion.

    On the other hand, there are also a vast number of people who are not intellectually honest, and who will never acknowledge your contributions. Even if no one else agreed with your analysis, you would still know you were right. Even if only one other person agreed with you, and that person was Wegman, then you should feel vindicated. Anyone else is just icing on the cake. However, in the political world, being right, and what is true, is not always relevant.

    AGW – a political theory that gained prominence in the late 20th century AD, and dominated the political landscape for approximately 100 years. Although the analysis of early proponents (eg, Mann, Hansen) were shown to be erroneous by McIntyre, he was ignored and the political movement marched on. Recent archealogical studies from the area known in that era as “Canada” have uncovered…

    -Encyclopedia Galactica

  2. Sam Urbinto
    Posted Nov 6, 2007 at 12:35 PM | Permalink | Reply

    This was very much needed, and makes the entire issue so much clearer.

  3. Larry
    Posted Nov 6, 2007 at 12:44 PM | Permalink | Reply

    The climate science community seemed unable to either refute McIntyre’s claims or accept them.

    Yup. It’s called caught between the devil and the deep blue sea.

  4. Larry
    Posted Nov 6, 2007 at 12:46 PM | Permalink | Reply

    I am baffled by the claim that the incorrect method doesn’t matter because the answer is correct anyway.

    It’s called “fake but accurate”. Tried and true in the media business.

  5. jae
    Posted Nov 6, 2007 at 12:48 PM | Permalink | Reply

    What a great summary! I wonder how the spin doctors will react.

  6. Larry
    Posted Nov 6, 2007 at 1:03 PM | Permalink | Reply

    FWIW, in this wikipedia entry:

    http://en.wikipedia.org/wiki/Ross_McKitrick#Criticism_of_Mann_et_al

    There’s a contested statement:

    A panel convened by the National Academy of Sciences rejected the main claims of McIntyre and McKitrick, and endorsed, with a few reservations the work of Mann and others [8]

    Anyone with any wikipedia pull may want to see about getting that cleaned up.

  7. ks
    Posted Nov 6, 2007 at 1:07 PM | Permalink | Reply

    From your article, “it doesn’t mean Dr. Mann’s conclusions are wrong”

    You never really addressed the conclusion of the work, nor the Mann 2003 paper.

  8. Bernie
    Posted Nov 6, 2007 at 1:19 PM | Permalink | Reply

    Excellent summary. Precise and compelling.

    Also Wegman’s equation can be re-written as
    Answer Correct = Bad Science – Method Wrong = Bad Science + Method Correct
    Leaving Mann on the horns of a dilemma of his making!!

  9. JP
    Posted Nov 6, 2007 at 1:20 PM | Permalink | Reply

    ks,
    This blog is filled with analysis of everything from Mann’s divergence problem(s), the use of the Foxtail Bristlecone as a temp proxy,as well as whitnoise failures.

    In short the famed HS is broken. I don’t think anyone seriously uses anymore other than for window dressing.

  10. Bernie
    Posted Nov 6, 2007 at 1:22 PM | Permalink | Reply

    ks
    You have missed the point of Wegman’s word equation.

  11. Larry
    Posted Nov 6, 2007 at 1:25 PM | Permalink | Reply

    To wit: if you have bad science, you don’t know that the answer’s correct. You end up with a circular argument. I thought this was obvious.

  12. Posted Nov 6, 2007 at 1:29 PM | Permalink | Reply

    Your summaries are great. I’ve been following your blog since startup, and I could still use a summary from time to time. Some of the threads are hard to digest if a person hasn’t been following the topic for a while.

    Maybe a new topic “Summaries” would be useful. I’m sure that newcomers to the site would eat these up.

  13. Sam Urbinto
    Posted Nov 6, 2007 at 1:36 PM | Permalink | Reply

    Larry, it’s the encyclopedia anyone can edit. And somebody has. I wonder if it will stay that way, the problem of anyone able to edit it. But it’s tagged at least: “The neutrality of this article is disputed.”

  14. Carl Gullans
    Posted Nov 6, 2007 at 1:42 PM | Permalink | Reply

    ks: He did, although not clearly, in noting that the hockey stick disappears without the inclusion of bristlecone pines. This is not a reverse cherry picking by McIntyre; see previous threads about incredible disparities between the temperature record from cores taken FROM THE SAME TREES.

    The failure of the models to crossvalidate was given rather light treatment, in my opinion. It, in fact, proves that a model is worthless.

  15. Mike B
    Posted Nov 6, 2007 at 1:55 PM | Permalink | Reply

    ks, this is from the Wegman Report:

    Overall, our committee believes that Mann’sassessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

    This speaks directly to Mann’s conclusions. Absent Mann, there is no evidence the decade of the 1990′s were the warmest of the last 1,000 years. But the Paleoclimate community continues to hockey-stick to the story, embarrasing themselves by carting Mannian Corpus about like a sort of “Weekend at Bernie’s” for AGW enthusiasts.

  16. Posted Nov 6, 2007 at 2:00 PM | Permalink | Reply

    I think I’ve asked before, but I will ask again:

    Rather than spend so much time going back and forth on a paper from 1998, why not perform a new analysis using proper statistical methods? What does the temperature trend look like if calculated correctly?

    This reminds me of the threads that found problems with the GISTEMP algorithm (distinct from the data problems circa 2000). In the end, those problems had no significant effect on the result. Do the MBH98 problems have a larger effect on the result? Does the trend still turn upward in the early 20th century?

    For those interested, a different summary of the “Hockey Stick Controversy” is available at Wikipedia:
    http://en.wikipedia.org/wiki/Hockey_stick_controversy

  17. John A
    Posted Nov 6, 2007 at 2:01 PM | Permalink | Reply

    Re #6

    The reason for the neutrality problem, as you can see from the Talk Page, is William Connelley – who is, amongst his other duties a Wikipedia Admin (which he abuses as much as he dares), an admin on RealClimate, a climate modeller at the British Antarctic Survey (obviously consuming a very small part of his time), and a political candidate for the Green Party in the UK.

    It was Connelley who started the biography of Steve McIntyre on WP and who notoriously started a ludicrous article on Wikipedia called “The Science is Settled” claiming that this phrase was invented by “skeptics”. When I kept adding a longer and longer list of pro-AGW scientists and politicians who kept saying more or less the same thing, first he suspended my IP address, then he deleted all the changes I had made, disappearing them completely from the record (and he was then made to put them back by another admin), then as the list grew longer and longer and was getting more and more difficult to refute (even for him), he gave up. One of his friends nominated the article for deletion and Connelley gave the weakest possible plea for it to be kept but alas it was finally deleted.

    For this reason, the coverage of climate on WP is extremely slanted toward the Connelley/Green Party POV.

  18. Steve McIntyre
    Posted Nov 6, 2007 at 2:20 PM | Permalink | Reply

    #16. John V, there are layers of problems. The “proxies” are not flawed temperature readings, but something quite different. Can one extract the “true” temperature signal by a “correct” statistical treatment of available proxies? Right now I don’t know how to go about it or even whether it is possible. That doesn’t mean that it is inappropriate to examine the efforts of people who purport to be able to do so.

    As to the 1998 paper, well, MAnn’s PC1 continues to be relied on in paleoclimate literature – it was used in Osborn and Briffa 2006, Hegerl et al 2006, Juckes et al 2007 and even illustrated as a temperature proxy (over my objections) in IPCC AR4. So it continues to be used in the present. If IPCC and the paleoclimate Team stopped using it, we could stop discussing it.

  19. Posted Nov 6, 2007 at 2:21 PM | Permalink | Reply

    Re #16:
    I forgot to add “in the USA lower 48″ when discussing GISTEMP. I will await the inevitable flames.

  20. Posted Nov 6, 2007 at 2:26 PM | Permalink | Reply

    #18 Steve McIntyre:
    Thanks for the answer.
    Can you provide some insight into the effect (magnitude) of the statistical errors in isolation? I can understand the problems with the proxies but the statistics are beyond me.

  21. Larry
    Posted Nov 6, 2007 at 2:26 PM | Permalink | Reply

    17, at the risk of being OT, that link says right up front:

    The science is settled

    The science is settled (edit|talk|history|links|watch|logs) – (View log)

    This appears to be an article about a slogan that nobody has ever used, except perhaps as a strawman argument, and even in that context is not particularly common.

    Correct me if I’m wrong, but isn’t that one of Gore’s stock sayings?

  22. Gunnar
    Posted Nov 6, 2007 at 2:28 PM | Permalink | Reply

    >> why not perform a new analysis using proper statistical methods?

    Because as I’ve pointed out to you more than once, the logic presented is simply completely insufficient. An upward trend does not AGW make.

    A while back, I went over this same ground wondering why we weren’t discussing actual AGW science, and I think I finally understand. The point of this blog is NOT to discover anything new about AGW. It is simply to audit what AGW proponents say. And as it turns out, this is also the most effective counter attack against AGW (although that’s not why Steve is doing this).

    In effect, the analog of your question is like:

    A meeting between potential investors, Steve M (who was hired by the investors), and folks from the mining company, and after having been proved that they faked the report showing that there was gold in dem der hills, they turn to Steve and say

    “well, if you’re so smart, you tell me where the ore is”.

    And if I’m right about all this, Steve’s response would be:

    “I don’t know, and I don’t care”.

    Steve and the investors then leave. The only issue was not whether the trend is up or down, but the integrity of the proponents.

    Steve: Gunnar, in your last part, I think that you’re (finally) catching on to my approach. I don’t assume that there’s gold in every patch of moose pasture or a “signal” in every concatenation of “proxies”. Look at a couple of my very early posts on Bre-X (or Enron).

  23. Peter Thompson
    Posted Nov 6, 2007 at 2:36 PM | Permalink | Reply

    John V., re: #22.

    The science is far from settled, but that should settle you a bit.

  24. Follow the Money
    Posted Nov 6, 2007 at 2:37 PM | Permalink | Reply

    My view, at the time, and it’s unchanged, was that their report was “schizophrenic”

    It was effective crisis management. You, Steve, presented a problemlatic idea on the march to green taxes and carbon credit transaction. They showed you correct, but went beyond their initial charge to rhetorically validate the result by comparison to a select few other questionable proxy studies. The warmers who want the funding to continue and the trading to proceed got a win, the NAS report is always cited for validating rapid global warming.

  25. Larry
    Posted Nov 6, 2007 at 2:42 PM | Permalink | Reply

    22,

    Because as I’ve pointed out to you more than once, the logic presented is simply completely insufficient. An upward trend does not AGW make.

    More to the point, An upward trend, coupled with a loosy-goosy model based on an incomplete understanding of the underlying physics does not AGW make.

    Neither do 4 polar bears, for that matter, but that’s all the evidence some people need.

  26. Jean S
    Posted Nov 6, 2007 at 2:45 PM | Permalink | Reply

    #16: Sorry for the strong words, but I say this as clearly as I can. Your comment shows complete lack of understanding the issue. If it were a simple thing to do, I’m sure Steve had done it. I personally do not believe that the large scale temperature reconstruction could be done with the current methodology and proxies. The only way I see it possible is to first construct a large number of high quality local reconstructions and then combine those. Currently, there does not exist enough (I know few that qualify) high quality records that could be combine to get even NH reconstruction. So IMO there is plenty of work to do even we can think of making ,e.g., NH recontruction .

    What comes to GISSTEMP, you seem to be drumming your own drum. I’ve been following your efforts, and although interesting, they do not give any possibility to claim “those problems had no significant effect on the result.” You do not simply know, you’ve been only considering (with simplistic methods) the best data set. You haven’t done any real statistical testing even for US48, so it is even premature to make any conclusions concerning the GISSTEMP US48 results, not to speak of the algorithm in general.

    Steve:
    I’ve moved John V’s response to this post over to USHCN #3 where GISTEMP issues are being discussed. As someone familiar with both MBH and GISTEMP issues, the issues are entirely different. I see little point in conflating discussion of the averaging of U.S. temperature records where a relatively decent record exists and where you know that the thermometers are thermometers with the discussion of proxy issues.

    I agree with Jean S, who understands these issues perfectly.

  27. Paul Penrose
    Posted Nov 6, 2007 at 3:09 PM | Permalink | Reply

    JS,
    The point is that since the methodology in MBH98 and MBH99 are wrong they can’t be used to support Mann’s conclusions, even if they are correct, and even if they are supported by “other evidence”. Search this site for information on Mann 2003 and you’ll find that it is suspect as well.

  28. Jaye
    Posted Nov 6, 2007 at 3:26 PM | Permalink | Reply

    Where is Boris when things really get interesting.

  29. Posted Nov 6, 2007 at 3:29 PM | Permalink | Reply

    Wegman wrote:

    We have been to Michael Mann’s University of Virginia website and downloaded the materials there. Unfortunately, we did not find adequate material to reproduce the MBH98 materials. We have been able to reproduce the results of McIntyre and McKitrick

    The best statician of the US cannot reproduce MBH.

  30. Sam Urbinto
    Posted Nov 6, 2007 at 3:29 PM | Permalink | Reply

    When I went to go copy it, I saw John Quiggin has updated the update.

    A panel convened by the National Academy of Sciences endorsed, with a few reservations the work of Mann and others [8]. However, one of the panel’s reservations was that “…a statistical method used in the 1999 study was not the best and that some uncertainties in the work ‘have been underestimated,’…” The panel concluded “Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium. The substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming.”[3]

    A subsequent investigation, undertaken at the request of Republican Senator Joe Barton and headed by Edward Wegman of George Mason University, supported the criticisms of McKitrick and McIntyre [9]

    8 is to an NYT article, 3 is a link to the NAS panel results, and 9 is to the PDF of the wegman report.

  31. Steve McIntyre
    Posted Nov 6, 2007 at 3:37 PM | Permalink | Reply

    #29. Another irony about Wahl and Ammann – which Hans is well aware of – is that the Wahl and Ammann emulation and our emulation of MBH98 coincided to 5 9′s using apples and apples, while neither of us was able to fully replicate MBH results. Both of us could sort of replicate their results, enough to draw conclusions; but there’s still something mysterious going on with MBH98, which annoys me like an unfilled square in a crosssword puzzle. As UC knows, you can’t replicate the AD1400 step using the present proxy roster. There’s some remaining mystery. It’s not a huge deal; it’s just annoying.

    Subsequent to the Wegman Report – in response to the House Committee – Mann archived part of his code. But it doesn’t work with the existing data archive. Actually this would be another useful project for the computer guys (Steve Mosher – are you there?).

  32. Stephen Richards
    Posted Nov 6, 2007 at 3:53 PM | Permalink | Reply

    Great summary Steve Mc!

    Even after retirement I still see the same old political machinations in the ‘official’ responses. No-one in authority is willing to stick his/her head above the parapete until the battle is won and then they will all rush to front, including the famous Gore, saying ‘I told you so’. You can see the beginnings in the responses above. Where you and M have begun to break the HS others are failing to ackowledge the origins of the breakages. It still sickens me to the stomach.

    CA just needs to keep doing the under-mining (pun, sorry)the roof will cave in eventually, I can see the cracks right now!!!

    GUNNAR —– Great, great analogy

  33. MarkR
    Posted Nov 6, 2007 at 4:00 PM | Permalink | Reply

    #30 Sam Urbinto

    supported the criticisms of McKitrick and McIntyre

    They make it sound like criticism made OF SteveM were supported, whereas it should be criticisms made BY SteveM.

    Definite attempts to mislead all the way through. Anyone got time to change it on Wikipedia?

  34. cbone
    Posted Nov 6, 2007 at 4:06 PM | Permalink | Reply

    “Anyone got time to change it on Wikipedia?”

    Don’t waste your time. Connolley will just revert anything that does not support his POV. As JohnA stated above, he rules the climate related pages with an iron fist.

  35. David H
    Posted Nov 6, 2007 at 4:26 PM | Permalink | Reply

    Re Richard Smith at the ASA. Who says plausible has odds of 2 to 1? Its evens at best

  36. John F. Pittman
    Posted Nov 6, 2007 at 5:12 PM | Permalink | Reply

    A small point, it appears that Vitosek and the NAS (North)Report are talking of two confounding influences. One is CO2 fertilization and the other is N fertilization…either or both could occur and would increase in general at the same time and amount wrt human fossil fuel burning.

    From:Human Domination of Earth’s Ecosystems
    Peter M. Vitousek, Harold A. Mooney, Jane Lubchenco, Jerry M. Melillo
    Science 25 July 1997:
    Vol. 277. no. 5325, pp. 494 – 499
    DOI: 10.1126/science.277.5325.494

    Reactive N that is emitted to the atmosphere is deposited downwind, where it can influence the dynamics of recipient ecosystems. In regions where fixed N was in short supply, added N generally increases productivity and C storage within ecosystems, and ultimately increases losses of N and cations from soils, in a set of processes termed “N saturation”

    The direct effects of increased CO2 on plants and ecosystems may be even more important. The growth of most plants is enhanced by elevated CO2

    From The NAS (North) Report

    While ‘strip-bark’ samples should be avoided for temperature reconstructions, attention should also be paid to the confounding effects of anthropogenic nitrogen deposition (Vitousek et al. 1997), since the nutrient conditions of the soil determine wood growth response to increased atmospheric CO2 (Kostiainen et al. 2004). (STR Preprint, 50)

    From the Richard Smith ASA newsletter

    Ed also touched on some of the other controversies in Mann’s work. Some of the proxies had been criticized as inappropriate. For example, bristlecone pines are known to be CO2 fertilized, creating a possible confounding problem if they are used in temperature reconstruction

  37. Michael Jankowski
    Posted Nov 6, 2007 at 5:41 PM | Permalink | Reply

    Re#16, ok, so if you don’t like a 1998 article, is 2003 recent enough? Try Mann and Jones (2003) http://www.ncdc.noaa.gov/paleo/pubs/mann2003b/mann2003b.html.

    Look at their “Locations of proxy data or reconstructions mentioned in this study.” Even with the flawed proxies, do you think that’s enough coverage to reconstruct either hemisphere or the global temperature?

    Whether you’re talking about reconstructing the temperature for the last 100 yrs, 400 yrs, 1000 yrs, of 2000 yrs, wouldn’t it be important to determine first exactly how much coverage would be necessary to generate any sort of accuracy in representing the globe?

    Let’s see someone demonstrate that before anyone looks at reconstructing the past.

    But to addrress your question more specifically…it turns out that if one takes the proxies used for MBH98 and takes out the ones which have serious issues (e.g., bristlecone pines), then the results are a load of crap (statistically speaking). So that wouldn’t fulfill any purpose. And, of course, most of the proxies are out-of-date, and other than Steve McIntyre, few people seem interested in bringing them up-to-date to see if they truly do reflect “unprecedented warmth.”

  38. Dev
    Posted Nov 6, 2007 at 7:21 PM | Permalink | Reply

    Very nice round-up, Steve. From the feedback I’ve been hearing from acquaintances, the last few posts have been extraordinarily powerful and compelling for intelligent non-techies who had previously accepted the AGW claim that “the science is settled.” Thanks.

    Maybe the seeds have finally been sown for a turning away from “consensus”, and returning back to the scientific method (wherever it leads). One is the way of science, the other is simply politics. I wish more people realized that.

  39. Jimmy
    Posted Nov 6, 2007 at 8:20 PM | Permalink | Reply

    If proxies follow temperature during a calibration period that is at the beginning of the industrial revolution when CO2 and N inputs were low – wouldn’t that make them good T proxies? A simple test should show that. If so, then why can’t one trust them back in time and use them in a reconstruction? I’m kinda confused….

    I agree that if there are CO2 issues and N issues, then the proxies are not so trustworthy now-a-days. But the good thing is that there are thermometer data once CO2 and N really start to increase – so we can use that data for the recent past.

    So what prevents Steve Mc from doing his own reconstruction with the data to see if a hockey stick pops up???

  40. Tom C
    Posted Nov 6, 2007 at 9:04 PM | Permalink | Reply

    Steve -

    I have always thought that Wegman’s reply to Stupak was a great piece of work. Calm and understated, but devastating. He did a great job of mining Wahl and Ammann for all the self-refuting evidence therein. It would be a good idea to keep highlighting it whenever possible.

  41. Jimmy Smith
    Posted Nov 6, 2007 at 9:10 PM | Permalink | Reply

    Subsequent to the Wegman Report – in response to the House Committee – Mann archived part of his code. But it doesn’t work with the existing data archive. Actually this would be another useful project for the computer guys (Steve Mosher – are you there?).

    I’m not Steve Mosher, but I have a graduate degree in a mathematically intensive field, and a background in, well let’s just say non-trivial software development, and I’d like to help. How would I go about it? Where’s the starting point?

  42. Gerald Machnee
    Posted Nov 6, 2007 at 9:29 PM | Permalink | Reply

    Re #39: **But the good thing is that there are thermometer data once CO2 and N really start to increase – so we can use that data for the recent past.**
    Check the other threads here, especially the one on the quality of observations. There are some issues there as well.

  43. bender
    Posted Nov 6, 2007 at 9:35 PM | Permalink | Reply

    The “recent past” is not the main or only issue. The issue is how the recent past compares to the not-so-recent past. (i.e. Is current warmth “unprecedented”?) In the one case you have instrumental records. In the other you have proxy-based reconstructions. Comparing them is not trivial. Maybe read the blog before commenting.

  44. Steve McIntyre
    Posted Nov 6, 2007 at 9:47 PM | Permalink | Reply

    #41. Jimmy, take a look at the post here . Bump the post if you want to discuss.

  45. Tim Ball
    Posted Nov 6, 2007 at 10:24 PM | Permalink | Reply

    Surely the measure of the lack of validity of Mann’s work and justification for Steve Mc’s position as confirmed by Wegman’s analysis is its almost total exclusion from IPCC AR4.

  46. Michael Jankowski
    Posted Nov 6, 2007 at 10:30 PM | Permalink | Reply

    So what prevents Steve Mc from doing his own reconstruction with the data to see if a hockey stick pops up???

    He could cross every t and dot every i…but if he didn’t get a hockey stick in the end, would that change anything with Mann, the IPCC, the general public, etc? The same people who disdain him now would disdain him then. They’d say, “Yeah, he didn’t get a hockey stick, but look at this spaghetti diagram of all the people who did!” And they’d still try to discredit him by pointing-out that he’s not a climate scientists. It would be a waste of his time. And that’s assuming one could come up with a relatively accurate historical reconstruction based on reputable and publicly-available proxies, etc, in the first place.

  47. Jimmy
    Posted Nov 6, 2007 at 11:22 PM | Permalink | Reply

    #42. So if all of the data is untrustworthy, how can one have any position at all? For or against?

    #43. Thanks for the advice. I would recommend that you read my entire post too. If the proxy correlates with temperature during a time when CO2 and N fertilization are minimal – it’s a good temperature proxy. If NOT – if precipitation, daylight, which side of the mountain it’s on, etc. are factors – then chances are it WON’T correlate with temperature records. And therefore it shouldn’t be included, right?

    #46. How would that be a waste of his time? What are you saying about this website then??? Besides, he’s probably done most of the work to do a reconstruction. In Steve’s 2005 GRL paper he already computed some of it. Why not just do it all, make his own reconstruction and put the nail in the coffin already??? That’s my point.

  48. Jan Pompe
    Posted Nov 6, 2007 at 11:34 PM | Permalink | Reply

    #45 Tim

    Surely the measure of the lack of validity of Mann’s work and justification for Steve Mc’s position as confirmed by Wegman’s analysis is its almost total exclusion from IPCC AR4.

    I would have thought so too but unfortunately this seems to be a point that is lost on many people. I still see often enough “but the hockey stick has been confirmed by 11(?) other studies”.

  49. Steve McIntyre
    Posted Nov 6, 2007 at 11:40 PM | Permalink | Reply

    Thanks for the advice. I would recommend that you read my entire post too. If the proxy correlates with temperature during a time when CO2 and N fertilization are minimal – it’s a good temperature proxy.

    It’s not as simple as that and (BTW I’m not convinced that CO2 and N fertilization are necessarily the most critical confounding problems.) Trees might well respond favorably to temperature increases in the cold 19th century but then not respond favorably to further increases in the 1990s and 2000s. How then would you know if they would recover a possible warm period in the 1000s.

    We presented the results of “apple picking” to the NAS panel showing that you could select proxies and “get” an MWP. What does this show any different than someone else’s cherry picking? If I put my critic’s hat, I would be just as critical of such an effort as I am of the little cherry picking exercises by the Team.

    I’ve shown on many occasions that trivial variations in proxy selection can reverse medieval-modern relations. Is this worth formalizing into an academic article? Perhaps. Ross McKitrick has been urging me to do this for a long time. But that’s a different thing than “presenting” an alternative reconstruction, something that I am reluctant to do given the present data quality.

    While there are some glaring errors in Team articles, the issue is not just methodology. If you had “good” data, it probably wouldn’t matter much how you handled it; it would be hard to miss any signal. I’ve done enough experiments with pseudoproxies to satisfy myself of this. There are some posts on this in May-June 2006. But it’s probably impossible to extract a temperature signal from the present poor quality data. Last year, two prominent young climate scientists told me at AGU (separately) that their diagnosis was that I had pretty much demolished the Team’s approach to millennial reconstructions using present (bad) data and that the only cure would be better data – which they thought might take 10-20 years.

  50. fFreddy
    Posted Nov 6, 2007 at 11:59 PM | Permalink | Reply

    So what prevents Steve Mc from doing his own reconstruction

    Same thing that prevents him doing a tarot card reading ?

  51. pliny
    Posted Nov 7, 2007 at 12:33 AM | Permalink | Reply

    #45 Tim Ball says

    Surely the measure of the lack of validity of Mann’s work and justification for Steve Mc’s position as confirmed by Wegman’s analysis is its almost total exclusion from IPCC AR4.

    But Steve says #18

    If IPCC and the paleoclimate Team stopped using it, we could stop discussing it.

    Which is it?

  52. Posted Nov 7, 2007 at 12:38 AM | Permalink | Reply

    #16

    Rather than spend so much time going back and forth on a paper from 1998, why not perform a new analysis using proper statistical methods? What does the temperature trend look like if calculated correctly?

    We can start from a simple stationary process model, and safely assume that this model produces greatly more accurate temperature estimates than tree rings but less accurate than thermometers:

    http://www.geocities.com/uc_edit/n_rec2.jpg

    Or, we can assume that the basic model of proxy vs. temperature relation is a valid model (scales are not zero, noise not very red), and use results from statistical literature (multivariate calibration papers)

    http://signals.auditblogs.com/2007/07/09/multivariate-calibration-ii/

    Either way, it seems that we have to agree with Jean S

    The only way I see it possible is to first construct a large number of high quality local reconstructions and then combine those.

    We should start with spatially well distributed 60 local reconstructions, that can reproduce the nearest rural thermometer record to 0.1 .. 0.2 C. Note that in recent reconstructions they have 10-20 proxies calibrated to global temperature.

    And pl. note that this old MBH99 result is still included in AR4 report Ch 6, fig 6.10. (b) and that 6.10. (c ) is constructed using published uncertainties that are all incorrectly calculated.

  53. JamesG
    Posted Nov 7, 2007 at 3:13 AM | Permalink | Reply

    You’re wrong if you think that the MBH hockey stick is no longer used. A leaflet I picked up at a renewable energy exhibition in France showed it large as life – without any other member of the spaghetti graph. It was used to refute the claim from a prominent French skeptic that it has been as warm in the past and it was placed there with commentary from the French group leader of the IPCC (GIEC) as if it was gospel. The whole sorry saga is clearly in revival mode.

  54. bender
    Posted Nov 7, 2007 at 4:36 AM | Permalink | Reply

    re #51
    pliny, read AR4 and you will see that it is not as black and white as you are making it out to be. The team argument is ‘MBH98 is irrelevant to the argument’ and ‘we’ve since moved on’. The reality is that derivative hockey sticks are still popping up in places (including AR4 chapter 6, Fig. 6.10), and though they’re not, strictly speaking, derived from MBH98, they’re still addicted to the “active ingredient” – the bristlecone/foxtail series. Wegman shows clearly that the various reconstructions are not in fact independent of one another. They share many common ingredients. i.e. They have not in fact “moved on”.

    Similarly, Gerry North has not much from NAS. We are still hearing about things “unprecedented” when the proof is just not there [yet?]. The paleo vs instrumental record is apples vs oranges. And the error on the paleo recon has not been estimated correctly. There is no basis for that comparison.

    Read the blog.

  55. henry
    Posted Nov 7, 2007 at 7:12 AM | Permalink | Reply

    If you want to see the other reconstructions, check here.

    http://www.ncdc.noaa.gov/paleo/recons.html

    Go through them, one by one, and note the simalarities, and see what data they used, and what each shows. These could also be used to refute other AGW statements (no MWP, no LIA, Regional effects, etc).

    Plenty of data, numerous abstracts and papers.

  56. Gary
    Posted Nov 7, 2007 at 10:32 AM | Permalink | Reply

    #49

    Last year, two prominent young climate scientists told me at AGU (separately) that their diagnosis was that I had pretty much demolished the Team’s approach to millennial reconstructions using present (bad) data and that the only cure would be better data – which they thought might take 10-20 years.

    Do you know if anyone is setting out the criteria for designing such an effort? The discredited approaches resulted from trying to wring explanations from available data rather than careful planning and execution of a complete research protocol. Better data are only half the solution.

  57. Bill
    Posted Nov 7, 2007 at 10:57 AM | Permalink | Reply

    A cardinal rule of statistical inference is that the method of analysis must be decided before looking at the data. The rules and strategy of analysis cannot be changed in order to obtain the desired result. Such a strategy carries no statistical integrity and cannot be used as a basis for drawing sound inferential conclusions.

    I wonder if researchers actually follow this rule? If there is some stage after which it actually becomes unethical to tinker with the strategy of analysis, what is that stage? I can only imagine that a researcher gathers his data first, then decides along what lines he needs to proceed, retooling the method of analysis as information is revealed. If strategies for drawing inferences from this data are governed by some kind of “Robert’s Rules of Order”, what is that text?

  58. steven mosher
    Posted Nov 7, 2007 at 11:00 AM | Permalink | Reply

    RE 28 where is boris when things get interesting?

    He’s enacting his name.

  59. steven mosher
    Posted Nov 7, 2007 at 11:04 AM | Permalink | Reply

    RE 41. Have a look Jimmy. The more brains the merrier.

  60. steven mosher
    Posted Nov 7, 2007 at 11:08 AM | Permalink | Reply

    RE 31. I’m here. Is this stuff in his nature archive or some other place.
    Toss me a pointer.

  61. andre
    Posted Nov 7, 2007 at 2:59 PM | Permalink | Reply

    Sandy Szwarc explains here, why the hockeystick will linger on and on.

    Mythbusting is though.

  62. ks
    Posted Nov 7, 2007 at 3:48 PM | Permalink | Reply

    following up…

    from the North/NAS/Committee on Surface Temperature Reconstructions for the Last 2,000 Years (not sure which is the common name) Report

    The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes the additional large-scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005, Rutherford et al. 2005, D’Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press), and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press). Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.

  63. Jeff Norman
    Posted Nov 7, 2007 at 3:54 PM | Permalink | Reply

    Steve,

    Excellent summary (and subsequent discussion btw).

    Re:#55 henry,

    I see that the NOAA has elected to ignore the North Report, particularly the part that says:

    The main reason that our confidence in large-scale surface temperature reconstructions is lower before A.D. 1600 and especially before A.D. 900 is the relative scarcity of precisely dated proxy evidence.

    All but one (Wilson et al) exceed this best after date.

    Jeff

  64. Bernie
    Posted Nov 7, 2007 at 4:42 PM | Permalink | Reply

    #62
    ks

    I am not sure whether you have seen one of these committees in action or not, but what you quoted is a fig leaf to cover the acute embarrassment of a heavily funded researcher being handed their head by an outside expert, a.k.a. Prof. Wegman. You accurately quote what is at the tail end of the report – but you should really read the meat of the report – or re-read Steve’s accurate and comprehensive summary of the debate. For the record it is possible that the last two decades have been the warmest two decades in 500 plus years – unfortunately Mann’s data is irrelevant to that conclusion as Prof. Wegman succinctly put it: Answer Correct + Method Wrong = Bad Science

    One reason why recognizing the importance of the fact that Mann’s statistical methods and hence conclusions are faulty is that to demonstrate that the current warming is unprecedented and therefore likely anthropogenic is that sufficiently precise paleoclimate temperature indicators and data is hard to come by. As someone else noted above, the failure of Mann et al reconstructions means that there are serious limitations in the current data-set and a significant effort will have to be undertaken to expand the data set. If Mann had in fact found a clear signal then a lot of uncertainty about the temperature record would have been reduced. Alas he did not: He found a series that just happened to have the shape of a signal that coincided with a part of the recent surface temperature record and appeared to support a strong AGW hypothesis. Wegman’s word equation is exactly right.

  65. MarkR
    Posted Nov 7, 2007 at 5:10 PM | Permalink | Reply

    #62 ks. The report summary and the report itself supported different conclusions. What was put out to the Press in summary gave cover to the Warmers. You’ve got to understand that the Warmers have Billions of Dollars, and their reputations on the line here. They aren’t just going to roll over. The summary I liked best at the time was from Von Storch, Zorita and Gonzalez-Raucen, and included the followong:

    3) We share the assessment of the NRC committee that the evidence for unprecedented warming of a single decade or even a single year in times prior to 1500, or so, is stretching the scientific evidence too far. However, this was the key claim made in the contested 1998-nature and 1999-GRL-papers by Mann et al.

    4) With respect to methods, the committee is showing reservations concerning the methodology of Mann et al.. The committee notes explicitly on pages 91 and 111 that the method has no validation (CE) skill significantly different from zero. In the past, however, it has always been claimed that the method has a significant nonzero validation skill. Methods without a validation skill are usually considered useless.

    Read the rest here.

  66. ks
    Posted Nov 7, 2007 at 5:25 PM | Permalink | Reply

    “what you quoted is a fig leaf to cover the acute embarrassment of a heavily funded researcher being handed their head by an outside expert”

    “You’ve got to understand that the Warmers have Billions of Dollars, and their reputations on the line here. They aren’t just going to roll over.”

    I’m skeptical of conspiracy theories. 3 can keep a secret if 2 of them are dead. I’m also skeptical that the National Academy of Science can be bought. Individual scientists, maybe… but committees from the NAS… get real.

    “Methods without a validation skill are usually considered useless.”

    does that also apply to Cook et al. 2004, Moberg et al. 2005, Rutherford et al. 2005, D’Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann (2006/2007 ?)

  67. MarkR
    Posted Nov 7, 2007 at 5:38 PM | Permalink | Reply

    #66 ks. Are you being deliberately obtuse? The NAS panel said Mann et al was without validation skill and useless. You’ve even got the page numbers. Go look it up. Regarding the other studies, as they mainly include the flawed Bristlecone data as Mann, or other non temperature proxies , I would say yes they are also useless. But why don’t you check for yourself what their validation statistics are before restating your prejudice? I think you will find they don’t provide the full range of validation, and especially not the R2. If you are intersted, look on the left sidepanel. and you will find links to all the commentary SteveM has carefully built up on these matters. Why not read them?

  68. MarkR
    Posted Nov 7, 2007 at 5:52 PM | Permalink | Reply

    #66 ks, In particular look at the heading “Spurious” where SteveM runs the rule over a lot of studies and their spurious correlation. Link

  69. Sam Urbinto
    Posted Nov 7, 2007 at 6:36 PM | Permalink | Reply

    Somebody should go check out Wikipedia, and if you have the sources from other published statisticians publically givin’ Dr. Wegman some props, add stuff to his bio showing it. It’s a stub and mainly focuses around the Entergy and Commerce hearing. It should have more stuff in there than just that.

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

    On a related note, I was reading the actual transcript of the hearing (haven’t finished it yet) I noticed one representative, Stupak, said (I don’t know if this is in the Wegman response to Stupak thread, because the file won’t download all the way)

    “The Majority paid for a report to independently verify the critiques of Dr. Mann’s 1999 research by a statistician but without any input from a climatologist.”

    Obviously ignorant of the facts (and what those before him said for the most part.)

    Dr. Wegman was not paid anything, nor was he trying to verify the critiques. He was trying to assess the statistical soundness of the original paper the critiques made. And some other things.

    Further, while it is not an issue to have a climatologist independently create statistical material, now dude has a problem when it’s the other way around. (Even ignoring the fact that Wegman with statistics is quite a different matter than person X with a model or tree rings or statistics or…)

    And there’s no politics involved. HAH! In marked contrast to what “denier Barton” said that seemed pretty fair (and as a bonus, mostly correct, vs what Stupak said that was mostly wrong.)

    Anyway so far it’s an interesting read.

  70. Acleron
    Posted Nov 7, 2007 at 7:38 PM | Permalink | Reply

    “Please read the comments below using the analogy from the previous post: see if any of our criticisms of Mannian parlor tricks have been refuted – as opposed to whether someone arguing that you can re-tool the trick to still saw the woman in half a different way.”

    If you think this is any way to debate an important scientific discussion please rethink your ideas. Describe them properly in a rational way and describe precisely what is wrong with the analysis of the data provided by climate scientists.

  71. MarkR
    Posted Nov 7, 2007 at 7:48 PM | Permalink | Reply

    #70 Acleron. Meet #65

  72. Bernie
    Posted Nov 7, 2007 at 8:12 PM | Permalink | Reply

    ks:
    I, for one, am not talking about a conspiracy, just typical bureaucratic behavior. It is obvious that you have not seen these panels in operation and read the reports that emerge from them. It is called spin, and scientists are certainly not immune from generating it when it meets their purposes. Having seen a number of research grant proposals I can assure you that the prospects are hyped and problems are diminished. These review processes are far from perfect, otherwise Mann’s falacious factor analysis would have been recognized at the time the original articles were submitted for publication.

  73. ks
    Posted Nov 7, 2007 at 10:31 PM | Permalink | Reply

    # 67

    “The NAS panel said Mann et al was without validation skill and useless.”

    As per your link, that was VZG’s response to NAS… not NAS. Clearly we are asking 2 different questions. I’m looking at “was the MWP warmer than today?” you seem to be focused on MBH 98 methodology. If MBH 98 used an incorrect method, that still does not answer the question I am looking to answer… and so I ask if there are the same method problems with the other 6 reconstructions (the NAS seems to think those methods are acceptable by including them in the report). I’m new to the nuances of the paleoclimate area so you’ll have to go slow with me and provide what links you can (hopefully a few non-CA links for verification purposes). Most of what I’ve briefly flipped through seems to require significant background which I do not possess. There is little way for someone just coming here to catch up. This post is at least a step in the right direction but I think it would be helpful for some starter posts that try to condense things. This post was waaay too long.

    You also introduced “flawed Bristlecone data” of which I am unfamiliar. I was confused by the following, “these reconstructions are functionally equivalent to reconstructions in which the bristlecone/foxtail pine records are directly excluded.” So if you could give me a good starting point.

    #72

    While I appreciate your insight into grant proposals, they are not the same as synthesis reports. The former serves a very different function than the latter and so criticism of one doesn’t translate to the other. And analysis is not part of the grant proposal so I fail to see how reviewing grants would impact the analysis of an article submitted for publication.

    In the end, I’m a newbie (which is why I’m in this thread). But I have seen a recording of Dr. North presenting on the NAS report/congressional hearing which I would recommend to you guys. From North’s presentation it seems that the NAS report had a more thorough review process prior to the hearing than the Wegman report.
    http://www.met.tamu.edu/people/faculty/dessler/NorthH264.mp4

  74. Mark T
    Posted Nov 7, 2007 at 10:38 PM | Permalink | Reply

    Actually, the NAS concluded that they were not that confident (whatever “somewhat less” means) in the period prior to 400 years ago. The studies they did use, btw, apparently also contained BCPs. I.e. they noted BCPs are poor proxies then relied on studies that used them. Link is here…

    http://www.climateaudit.org/?p=715

    Mark

  75. Mark T
    Posted Nov 7, 2007 at 10:50 PM | Permalink | Reply

    Describe them properly in a rational way and describe precisely what is wrong with the analysis of the data provided by climate scientists.

    Dude, get with the program. They’ve done this repeatedly and they’re simply getting tired of people bringing the same nonsense arguments up over and over again after M&M have repeatedly been proven correct in nearly every point they’ve made. Rationality went out the window long ago, and folks like Steve are simply tired of reiterating the same points that everyone in the world understands outside of climate science. This is a pretty big blog, do some reading.

    Mark

  76. Dave Dardinger
    Posted Nov 7, 2007 at 11:21 PM | Permalink | Reply

    Mark,

    I don’t know that Steve really gets tired of answering polite questions about his major areas of expertise. But it is necessary to read some of the major posts on the subject. That’s where the “Categories” box on the left side top can be very useful.

    For instance ks asks:

    I ask if there are the same method problems with the other 6 reconstructions

    And if he makes a list of them as he did in post 45 above:

    Cook et al. 2004,
    Moberg et al. 2005,
    Rutherford et al. 2005,
    D’Arrigo et al. 2006,
    Osborn and Briffa 2006,
    Wahl and Ammann in press

    and then goes to the top he’ll find posts on both Moberg and Osborn & Briffa and they will probably have refs to others in the group. There’s also a subject of Bristlecones which I’m sure has a number of posts in it.

    If kc will read some of the main posts s/he can then ask questions based on what was read.

  77. Mark T
    Posted Nov 7, 2007 at 11:48 PM | Permalink | Reply

    I don’t know that Steve really gets tired of answering polite questions about his major areas of expertise.

    Perhaps Steve isn’t tired of it, but I can’t imagine why not after what, 3 or 4 years of it? ;) Particularly given that this thread is pretty much exactly what Acleron asked for, with a clear exposition of what is wrong with the Teamspeak and why serious science agrees with his opinion. Not in a consensus sort of way, mind you, because then we’d probably all get loopy and try to beat him back down under the guise of “consensus is meaningless!” ;)

    Mark

  78. James Lane
    Posted Nov 8, 2007 at 12:00 AM | Permalink | Reply

    #73 ks

    The studies that Dave D. lists above all use the BCPs, either directly or in the form of Mann’s PC1 (the principal component on which the BCPs load). Why the NAS panel should advise against the use of strip-bark samples in temperature reconstructions, yet cite these other studies approvingly is something of a mystery.

    One of the reasons that it can be difficult to get a handle on the paleoclimate controversy is that MBH is a dark laboratory of statistical horrors and subject to criticism on a number of levels. But at the end of the day it’s about getting the BCPs into the reconstruction. The BCPs impart the hockey stick shape, the rest of the proxies are basically just white noise.

    I would recommend you start by reading “What the HS debate is about” located in the left hand side-bar under favourite posts. Then look at the posts about post-MBH reconstructions. Here’s one specifically about the NAS panel on BCPs:

    http://www.climateaudit.org/?p=727

  79. Curt
    Posted Nov 8, 2007 at 12:11 AM | Permalink | Reply

    #73 ks: You are being facetious, aren’t you, when you say, “From North’s presentation it seems that the NAS report had a more thorough review process prior to the hearing than the Wegman report.”

    If you listen to the presentation you link to, you hear North say they “didn’t do any research”, that they just “took a look at papers”, that they got 12 “people around the table” and “just kind of winged it.”

    It is worth spending time going through the archives here. A lot of this stuff has been covered many times. For example, this page:

    http://www.climateaudit.org/?p=809

  80. ks
    Posted Nov 8, 2007 at 12:16 AM | Permalink | Reply

    #74

    The NAS panel concluded that for 30 year averages this was the warmest in 400 years with “likely” probability (>66%). The NAS panel concluded that for 30 year averages this was “plausable/reasonable”-y the warmest in 1000 years and it was “impossible to bring a convincing argument against” that conclusion.

    *as per North’s presentation I linked

    #76

    Would you please provide a starting point? This looks like 2322 post on the website and that is a lot to dig through. Clicking on Wahl and Amman… I get the stories in reverse chronology which doesn’t help. Going back to the first substantiative post http://www.climateaudit.org/?p=205 I get “So far I don’t see anything in W-A that affects any of our results.” But I’m unaware what “our results” are, so it is difficult to interpret the rest. The bottom line is that there are an immense amount of postings and many of the postings are very verbose. It would be nice for some assistance in navigating beyond the “categories” toolbar.

  81. Mark T
    Posted Nov 8, 2007 at 12:16 AM | Permalink | Reply

    That’s a good point. Wegman actually tried to reproduce the various studies, only succeeding with M&M and adequately pointing out that their’s wasn’t even a reconstruction in the first place!

    Mark

  82. Mark T
    Posted Nov 8, 2007 at 12:35 AM | Permalink | Reply

    The NAS panel concluded that for 30 year averages this was the warmest in 400 years with “likely” probability (>66%). The NAS panel concluded that for 30 year averages this was “plausable/reasonable”-y the warmest in 1000 years and it was “impossible to bring a convincing argument against” that conclusion.

    Now you’re wordsmithing. Plausible/reasonable means exactly what in a scientific sense? 66% confidence? Give.Me.A.Break. They also, as noted in several posts, still relied on the very BCP studies they said should be avoided. The results of their own analysis does not even come close to supporting their obvious two-sided comments.

    Mark

  83. Mark T
    Posted Nov 8, 2007 at 12:37 AM | Permalink | Reply

    Would you please provide a starting point?

    I believe if you actually do a search on the exact phrases Dave used, e.g. “Wahl and Amman in press” you’ll find the relevant threads.

    Mark

  84. MarkR
    Posted Nov 8, 2007 at 12:57 AM | Permalink | Reply

    #73 ks.Yes it was von Storch et al summary of what the NAS report said.

    Reconstructions that have poor validation statistics (i.e., low CE) will have correspondingly wide uncertainty bounds, and so can be seen to be unreliable in an objective way. Moreover, a CE statistic close to zero or negative suggests that the reconstruction is no better than the mean, and so its skill for time averages shorter than the validation period will be low. Some recent results reported in Table 1S of Wahl and Ammann (in press) indicate that their reconstruction, which uses the same procedure and full set of proxies used by Mann et al. (1999), gives CE values ranging from 0.103 to –0.215, depending on how far back in time the reconstruction is carried. Although some debate has focused on when a validation statistic, such as CE or RE, is significant, a more meaningful approach may be to concentrate on the implied prediction intervals for a given reconstruction. Even a low CE value may still provide prediction intervals that are useful for drawing particular scientific conclusions.

    The work of Bürger and Cubasch (2005) considers different variations on the reconstruction method to arrive at 64 different analyses. Although they do not report CE, examination of Figure 1 in their paper suggests that many of the variant reconstructions will have low CE and that selecting a reconstruction based on its CE value could be a useful way to winnow the choices for the reconstruction. Using CE to judge the merits of a reconstruction is known as cross-validation and is a common statistical technique for selecting among competing models and subsets of data. When the validation period is independent of the calibration period, cross-validation avoids many of the issues of overfitting if models were simply selected on the basis of RE.

    NAS Report online

    Mann et al and subsequent have no skill. The report then states the conclusions as being plausible etc, but they are not based on the treee ring proxies, they are now based on borehole data, which is equally subject to selection bias. You may ask how they can go from “no skill” to plausible. Hopefully you can see the disconnect there. It is at that poinjt that the summary diverges from the body. Their motives for doing that are not known.

    As to the rest you need to educate yourself as to why Bristlecones etc are not temperature proxies.

    Basically the climatologists who have produced hockey stick shaped graphs have done so by carefully selecting proxies that produce the results they want. In some cases they have used definite non temperature proxies, in others they have used the most favourable set of a number of sets of results for the same type of Proxy. In Manns case he used a FORTRAN programme which produced a Hockey Stick whatever dat you put in.

  85. Jonde
    Posted Nov 8, 2007 at 1:20 AM | Permalink | Reply

    Just for all of you who are long time CA readers. Please, have patience with new members who has come here because of exposure of Science Poll. CA is highly scientific, not a chit-chat discussion blogs that most of the blogs are nowadays. It is a enormous task to read and study all the aspects in short time. I would highly suggest someone to make a new topic that has most easily digestible information about Mann and BCP (scientific one). This way the initial step for newcomers would be slightly lower and they would also have a patience to stay in here and join the discussion.

    Now is a perfect opportunity to show that CA is not a junkie blog, but the most scientific blog in climate science in the web.

  86. James Lane
    Posted Nov 8, 2007 at 1:23 AM | Permalink | Reply

    kc

    The NAS panel concluded that for 30 year averages this was the warmest in 400 years with “likely” probability (>66%). The NAS panel concluded that for 30 year averages this was “plausable/reasonable”-y the warmest in 1000 years and it was “impossible to bring a convincing argument against” that conclusion.

    I don’t think anyone here disputes that modern temperatures are warmer than in the last 400 years (the Little Ice Age). If the NAS panel says it’s “plausible” that temperatures are higher than in the last 1000 years (citing the post-MBH papers I referred to above), I suggest that it’s also “plausible” that temperatures in the MWP were as warm or warmer as modern temperatures (there is also evidence for this proposition as well).

    I am not an AGW denier, but I object to the lack of emphasis on the uncertaintity contained in these reconstructions.

  87. Philip_B
    Posted Nov 8, 2007 at 1:51 AM | Permalink | Reply

    the warmest in 400 years with “likely” probability (>66%)

    So their confidence is slightly better than random chance (50%) in determining the answer to a binary question. Most of us would call that a ‘don’t know’.

    Otherwise like many statements in the GW arena, carefully crafted to say different things to scientists and non-scientists – 66% will sound like a lot to many people.

  88. R John
    Posted Nov 8, 2007 at 2:22 AM | Permalink | Reply

    #17 John A -

    The reason for the neutrality problem, as you can see from the Talk Page, is William Connelley – who is, amongst his other duties a Wikipedia Admin (which he abuses as much as he dares), an admin on RealClimate, a climate modeller at the British Antarctic Survey

    OT – thanks for this insight as I’ve noticed that ANYONE who questions AGW theory has a negative entry on Wikipedia. I was beginning to think that all of my friends were wackos, but now I know that it is a VAST AGW conspiracy!

    As for the topic on hand (from the view of a chemist) when results cannot be re-created via the author’s instructions from the “Methods and Materials” section of a submitted paper, then the reviewers of that paper will reject it as fast as the NHC will name a swirl in the Atlantic basin. Thus, I’m troubled by the fact that climate related papers like MBH99 made it through the scrutiny process before being published. Repeatability of results is one of the basic tenets of science.

  89. R John
    Posted Nov 8, 2007 at 2:29 AM | Permalink | Reply

    I am not an AGW denier

    I would propose that in this era of Political Correctness, we should demand to be called…

    AGW Skeptics

  90. TAC
    Posted Nov 8, 2007 at 3:18 AM | Permalink | Reply

    ks (#66): You make an interesting point that there is peer-reviewed literature on both sides of this issue, some seeming to support MBH methods and conclusions and others discrediting them. You are also absolutely right to be skeptical when scientific assertions are justified by the titles and reputations of the individuals involved. Such argument amounts to no more than rhetoric and noise; it is not science.

    How should one sort this out? Set aside some time to read all the papers, including MBH, M&M, Wegman, NAS/North, etc. Work through their arguments.

    If you have some statistical talent, implement the MBH method and test M&M’s assertions (Monte Carlo simulations will suffice). Explore various error structures; try some real proxies and pseudo proxies. Explore cases where at least one proxy has a hockey-stick shape.

    This is how science — the real kind — is done. You should not blindly trust the NAS or Wegman or Michael Mann or Steve McIntyre (or me, for that matter).

    If you follow these steps, you will learn a lot about multivariate statistics, you will know for sure where the truth lies, and you will have acquired a renewed appreciation for real science. These are not trivial rewards.

    Finally, keep in mind that flawed research and deplorable conduct reflect only upon the scientists who exhibit them. They reveal nothing about the natural world.

  91. Geoff Sherrington
    Posted Nov 8, 2007 at 3:36 AM | Permalink | Reply

    Suggestion: Take the high moral ground and refer to yourself as a “Politically correct man-made-warming skeptic”. This blog has now become influential enough, and has withstood so much criticism by adducing fair answers, to be able to stand as a central reference point, not a faction on the fringe – if it ever was.

  92. John A
    Posted Nov 8, 2007 at 5:23 AM | Permalink | Reply

    Steve McIntyre:

    I’ve shown on many occasions that trivial variations in proxy selection can reverse medieval-modern relations. Is this worth formalizing into an academic article? Perhaps. Ross McKitrick has been urging me to do this for a long time. But that’s a different thing than “presenting” an alternative reconstruction, something that I am reluctant to do given the present data quality.

    I agree with Ross. It’s worth another paper.

  93. MarkW
    Posted Nov 8, 2007 at 5:58 AM | Permalink | Reply

    ks,

    If you are unaware of the controversy surrounding the bristlecone proxies, then you have not studied this issue enough to form an opinion.

  94. Carl Gullans
    Posted Nov 8, 2007 at 10:21 AM | Permalink | Reply

    I think ks’s request for a summary of the issues in question is not a bad idea. This post accomplished a summary of the main arguments against the tree-ring based proxy reconstructions, but some people might not even know what those are. I am not saying that the site should ever cater to those people, and I don’t expect Steve to ever use his time writing something so basic… but if the blog continues becoming more and more popular it might become inundated with requests to go back to the basics. Furthermore, we want people to read and comprehend the information here… they will aruge with True Believers and send them here to examine the evidence for themselves. This will further strengthen Steve’s work (by withstanding criticisms).

    Anyway, and along those lines, may I propose something to allow the topics here to be an easier read for the lazy and the non-climatologists?

    First off, in any topic discussed here, there are many acronyms (MBH, ROW, NH, GISS, NAS, USHCN) that newcomers to the site, especially curious minds not familiar with climate science, may have trouble deciphering. I’ll admit that something as simple as ROW took me about a week to figure out. Steve, would you object to someone writing a glossary/dictionary for CA to explain these terms? It could go into definitions of words like dendrochronologist, bore hole, UHI, etc.

    Secondly, outside of the normal threads, might there be a super-condensed summary of each topic for the uninformed? I’ll give an (almost full) example of what I mean:

    “It is widely cited that we are in the hottest decade of the past millenium. Such statements are based upon taking cores of trees, sediments, or ice (among other things) that have been around for at least that long. These cores are said to have something measureable within them that is highly correlated with temperature, and so if one analyses the cores one should be able to obtain good estimates of past temperatures.

    In stating that the 1990s were the hottest years of the millenium, the majority of studies that support this idea use cores from bristlecone pine trees among other cores. Tree cores are though to be good measures of past temperature (or, are a “proxy” for temperature) through the widths of tree rings contained in the core; tree rings generally occur once a year and have a width that is correlated to temperature. However, the efforts of ClimateAudit have revealed that using bristlecone pines is a serious error that invalidates the majority of studies that have looked at temperatures since a thousand years ago.

    Climate Audit has found:

    -While tree ring width is correlated to temperature, it is also very correlated to precipitation. This is a confounding variable not accounted for.

    -Tree rings will get wider with warm temperatures, and narrower with cold temperatures, but they will also get narrower with very hot temperatures.

    -Bristlecone pines growth may be correlated with CO2 (independent of temperature), which would invalidate their use as a temperature proxy.

    -Many of the cores used as data in the tree ring studies come from trees that have had their bark stripped off. These strip-bark trees contain the vast majority, if not all, of the hockey stick shaped temperature histories…

    etc.

    etc.”

    This would probably work best as a Wiki, as this allows working definitions of the state of the issues to exist. Suppose someone read such a page and presented convincing evidence that bristlecone pines were not CO2 fertilized; one could then alter that bullet to state “.. were thought to be CO2 fertilized.. but recent evidence [footnote reference] suggests that they are not”. Summaries like this also help organize what we do and do not know, what are speculations and what are supported arguments, as well as provide information for newcomers. It also provides a focal point for attacks from the AGW crowd, who should be welcome to audit steve’s findings… in lieu of finding errors or criticisms, the findings are strengthened and become more well-known.

    I hope that all made sense… it seems like a good idea. Let me know what you think, Steve!

  95. Mark T.
    Posted Nov 8, 2007 at 11:08 AM | Permalink | Reply

    -While tree ring width is correlated to temperature, it is also very correlated to precipitation. This is a confounding variable not accounted for.

    As well as CO2, soil quality and sunlight. CO2 and temperature are correlated by hypothesis, so using a method to extract them that is based on an assumption of uncorrelated inputs (PCA) is a fools errand.

    -Tree rings will get wider with warm temperatures, and narrower with cold temperatures, but they will also get narrower with very hot temperatures.

    I.e. the response is non-linear (and not monotonic) and using linear extraction methods renders it impossible to tell which side of the “curve” you are on.

    -Bristlecone pines growth may be correlated with CO2 (independent of temperature), which would invalidate their use as a temperature proxy.

    See above.

    -Many of the cores used as data in the tree ring studies come from trees that have had their bark stripped off. These strip-bark trees contain the vast majority, if not all, of the hockey stick shaped temperature histories…

    I think this would be called the icing on the cake of reasons why not to use BCPs in particular.

    Mark

  96. Mark T.
    Posted Nov 8, 2007 at 11:11 AM | Permalink | Reply

    Btw, I think your idea of an attached wiki sort of reference page is a good idea. As well as an acronym list posted conspicuously on this page. I’ve been reading this blog for years and I _still_ get lost in some of the climatespeak, and the blog itself is so large that we run into instances of newbies making comments about things that have been beat to death. :)

    Mark

  97. Posted Nov 8, 2007 at 11:47 AM | Permalink | Reply

    Very nice summary, Steve.

    KS provides a useful sounding board and counter-point for Steve’s excellent presentation. This is the kind of back and forth that should be encouraged as much as possible, with intelligent members of the public and research community who are still favorably impressed by Mann et al.

    If not for Steve, such open discussion formats would be almost nonexistent.

  98. David Holland
    Posted Nov 8, 2007 at 12:20 PM | Permalink | Reply

    Steve,

    This might be the appropriate place to mention that I have put up at http://tinyurl.com/2szwh8 a paper I have written entitled “Bias And Concealment In The IPCC Process: The “Hockey-Stick” Affair And Its Implications” It will appear in the upcoming issue 7+8 of Energy and Environment.

    David

  99. Reid
    Posted Nov 8, 2007 at 12:32 PM | Permalink | Reply

    Re #98,

    Thanks David Holland. The paper is exactly what is needed. [snip]

  100. Ross McKitrick
    Posted Nov 8, 2007 at 12:52 PM | Permalink | Reply

    Re #98: Excellent paper David. Thanks for writing the chronicle. It’s a story that needs to be read. Though it should probably include a warning for those with high blood pressure to keep their medicine nearby.

  101. JP
    Posted Nov 8, 2007 at 12:59 PM | Permalink | Reply

    #62
    KS,
    You remove the Foxtail Bristlecone from MBH9X and you remove the Hockey Stick. Very few on the Team even attempt to answer the divergence problems (how can a proxy be accurate if it cannot even be calibrated to local temps?)

    So, Mann weighted his reconstruction on a single species of tree, which supposedly reflects long term global temps , but does not relfect the local temperature trends.

  102. Dave Dardinger
    Posted Nov 8, 2007 at 1:55 PM | Permalink | Reply

    re: #96

    As well as an acronym list posted conspicuously on this page.

    There is an acronym page. The link is on the top left in the middle of the box labled “pages” I was written by Willis a while back and could probably use some updating. I notice ROW isn’t listed.

  103. Mark T.
    Posted Nov 8, 2007 at 2:08 PM | Permalink | Reply

    Oh, cool, I hadn’t noticed that before. Not very “conspicuous.” :)

    Mark

  104. Paul G M
    Posted Nov 8, 2007 at 3:11 PM | Permalink | Reply

    David Holland

    Please e-mail me at pmaynard@pmaynard.plus.com

    Thanks

    Paul

  105. T J Olson
    Posted Nov 8, 2007 at 3:32 PM | Permalink | Reply

    Please excuse my late appearance.

    At CIRES (Nov. 2), North stated that “cherry picking” is a legitimate method in paeloclimatology. Because one is looking for a certain, elusive “signal’ from the noise, that’s the only way to find the data. North cited his earlier career work in paleoclimatology as a basis for his expert opinion.

    In short, paleoclimatologists recognize a methodology that other fields easily criticise or dismiss. Either one accepts the former’s self-referencing authority or one rejects it.

    This impass seems endemic – and thus a way forward with the relevant science that the the Congressional Sub-Committee had hoped for has not emerged since last year’s reports.

    Now, if there remained sympathetic leadership within Congress, this larger methodological issue could be examined through similar channels. But since there is not, and it is unlikely to change soon, alternative approaches ought to be pursued.

    Another way is to have the relevant sub-groups within the American Statistical Association take up the question. Wegman and others would appear to be the most important contacts for furthering such an effort.

  106. Willis Eschenbach
    Posted Nov 8, 2007 at 4:26 PM | Permalink | Reply

    Yeah, I wrote the acronym page, but now that it’s posted, I don’t know how to update it so the ROW (rest of the world) will know WTF we’re doing …

    w.

  107. Pat Keating
    Posted Nov 8, 2007 at 4:38 PM | Permalink | Reply

    Because one is looking for a certain, elusive “signal’ from the noise, that’s the only way to find the data.

    As someone who has some expertise in signal-processing, I can assure you that cherry-picking is not a reliable way of picking a signal out of noise.

    It may be elusive because it ain’t there…..

  108. John F. Pittman
    Posted Nov 8, 2007 at 5:37 PM | Permalink | Reply

    #98 Thank you. I started reading it at work and couldn’t wait to get home and finish it. I want to particularily commend you on the cogent style.

  109. trevor
    Posted Nov 8, 2007 at 6:57 PM | Permalink | Reply

    Re #106: WTF? There is another term that should be explained in the glossary :-)

  110. T J Olson
    Posted Nov 8, 2007 at 6:57 PM | Permalink | Reply

    re #107

    Precisely the issue so dilengently raised here.

    My sense is that paleoclime- is an art in search of a science. For instance, I find birth-order effects useful in appraising strangers I meet. This assumes a fairly close birth relation among siblings; all dice are off without it. Yet the statistics of this applied science remain quite controversial. Randomized studies frequently fail to find any birth order effects. Take for, example, the criticism heaped on the seemingly conclusive studies of Frank Sulloway on birth-order effects in science history.

    It is plain that the effects paleoclim’s want to measure do require selection. However, the precise variables that must be controlled in order to find good measurements vary with the species. Seasonal watering, CO2 levels absorbed, exposure to sunlight – and thus aspect – as well as elevation, all come into play – and more. Tree-ring series without this level of “due diligence” will become contaminated with those lacking much precise selection in a meta-analysis like those done by MBH.

    What to do? Since so much is riding on an uncertain art and imprecise science, only further methodological debate, exposure, and interdisciplinary consensus about legitimacy will allow us to place the needed level of confidence in results like MBH. Contrary to Steve and others last year who thought the “Hockey Stick” controversy didn’t mean much to AGW science or policy, I think it does. Many claim urgeny for action on AGW because we are living in the warmest period in 1,000 or 400 (as North claims) years, and this is because of added anthropogenic CO2. Such studies underpin causal inference from these correlations.

    This would be all fine IF we could have legitimate confidence in these claims. But unfortunately, after many years and billions of dollars, we still don’t have anything but crude mechanical notions of how AGW occurs, and – except for satellite measurements far above the ground – even cruder levels of confidence in measuring actual temperature change. “Alarmists” shouldn’t be surprised that their confident (or strident) proclamations don’t receive universal assent. They don’t merit it.

    Getting back to the science, other venues for exploring the methedological legitimacy of paleoclimatology is include American Geophysical Union and American Geographical Association. In order to undertake this, prospects need to be identified, lobbied and organized.

  111. Andrey Levin
    Posted Nov 8, 2007 at 7:04 PM | Permalink | Reply

    Re#109:

    It is Whiskey, Tango, Foxtrot.

    Roger that, Trevor?

  112. steven mosher
    Posted Nov 8, 2007 at 8:14 PM | Permalink | Reply

    BCH?

  113. Mark T
    Posted Nov 9, 2007 at 12:20 AM | Permalink | Reply

    Bose, Chaudhuri and Hocquenghem?

    Mark

  114. MarkR
    Posted Nov 9, 2007 at 6:27 AM | Permalink | Reply

    #6 Willis. When you do update it, can you include FUBAR, one of my personal favourites from the Military, who are masters of the Acronym, as FUBAR is already overdue for employment for a description of the state of IPCC and Hockey Team worldview of Climate Science.

  115. MarkW
    Posted Nov 9, 2007 at 6:32 AM | Permalink | Reply

    What The Fudge,

    used by confectioners when their chocolate treats go awry.

  116. Geoff Sherrington
    Posted Nov 9, 2007 at 7:02 AM | Permalink | Reply

    Re # 105 T J Olson

    At CIRES (Nov. 2), North stated that “cherry picking” is a legitimate method in paeloclimatology. Because one is looking for a certain, elusive “signal’ from the noise, that’s the only way to find the data.

    “Cherry picking” is not a formal part of the scientific dictionary and even now it means different things to different readers. North’s words, if accurately quoted and in context, are equivocal.

    Abuse of data happens when results are chosen to suit the result desired. This can mean inventing observations that do not exist, or rejecting observations that are inconvenient. This is what is often meant by “cherry picking”. This is bad. No reputable scientist would lend his name to it. It is lack of truth by commission or by omission.

    Misuse of data can happen when “outliers” are rejected as inconvenient or disruptive of a broader statistic. However, it is precisely in outliers that some information-rich discoveries have been made. This could be named “picking the rich cherry”. The rejection of such outliers without asking why is bad. Admittedly, some data sets have so much noise that outliers cannot feasibly be examined one by one.

    A good deal of the palaeoclimate data shown on these CA pages is noise rich, signal poor and it’s not worth chasing the rich cherry.

  117. yorick
    Posted Nov 9, 2007 at 9:37 AM | Permalink | Reply

    In the end, those problems had no significant effect on the result.

    –John V

    The effect was that the trend was less than originally reported when the high quality sites were used. This is in the US where the trend id less that the ROW anyway. This is not insignificant, no matter what Eli Rabbet’s eyballing of the data says. The ROW has not been studied with a skeptical eye to a meaningful extent. One can safely assume that the liklihood of similar problems existing there is significant.

  118. Andrey Levin
    Posted Nov 9, 2007 at 2:13 PM | Permalink | Reply

    MarkR:

    According to Wiki:

    …”repair” in FUBAR can be replaced with either “redemption,” “recognition,” “rescue,” “reality,” “recovery,” “relief,” or “reason.”

    This is rich.

  119. steven mosher
    Posted Nov 9, 2007 at 5:39 PM | Permalink | Reply

    RE 113. Hehe. I wonder how many are confused by BCH?

    We also used to say something was Tango Uniform.

    or TU and taking on water.

    ever hear that one? if not ESABAM.

  120. GTTofAK
    Posted Nov 9, 2007 at 9:15 PM | Permalink | Reply

    #6 et. al. dont waste your time with wikipedia. William Connelly controls those articles with an Iron fist thanks to his admin powers. Making Connoly an admin is one of the dumbest things wikipeia could have ever done. Connelly like most all other global warming internet shills gleefully engages in the reputation attacks of skeptics and uses wikipedia to do it. Some figure can have a nice little stub for years that gets no traffic but the moment they says something public about global warming there is William. And his been doing it for a long time well before he was an admin.

    Wikipedia due to its open nature skirts the boarder between legal documentation and libel. The independence of the authors is the only protection they have. By making Connelly and admin they have endorsed his practice of using wikepedia for the purposes of attacking the reputation of those he disagrees with. One of theses days Connelly will go to far when trying to discredit a skeptic and is going to get not only himself sued for libel and wikipedia along with him. And by making him an admin in effect endorsing him wikipedia will not be able to slither its way out of it like they do with most of the libel suits they get.

    In fact I don’t know why a skeptic who’s reputation has been besmirched by Dr. Connelly on wikipedia hasn’t sued Dr. Connelly and wikipedia in his home of Brittan. I have followed his history on wikipedia for a long time and in my opinion he has made some edits about skeptics for which an English court with their far stricter rules for libel than America could very well find Dr. Connelly and wikipedia liable.

  121. Posted Nov 9, 2007 at 9:27 PM | Permalink | Reply

    I only have a reason to give my thanks to Wikipedia. Their article on Astrobiology includes a link to my conference on Astrobiology.

  122. _Jim
    Posted Nov 9, 2007 at 10:42 PM | Permalink | Reply

    or TU and taking on water.

    Used that one just the other day! (literally: mammatus up – to indicate a ‘module’ which had ‘died’)

    ever hear that one? if not ESABAM.

    e*t s*** and bark at [the] moon?

  123. Posted Nov 9, 2007 at 11:07 PM | Permalink | Reply

    The following quote caught my eye:

    Mike Wallace’s talk was about the “National Research Council Report on the ‘Hockey Stick Controversy’…
    The charge to the committee, was “to summarize current information on the temperature records for the past millennium, describe the main areas of uncertainty and how significant they are, describe the principal methodologies used and any problems with these approaches, and explain how central is the debate over the paleoclimate record within the overall state of knowledge on global climate change.” This was deliberately framed to give a broader overview than the charge to the Wegman committee, which was specifically focused on Michael Mann’s papers and the critiques of those papers.

    Is this an accurate portrayal of what happened? I thought that the NAS was charged with answering a specific set of questions regarding the MBH Hockey Stick, and that this objective somehow got watered down (“framed to give a broader overview”) between Cicerone and North. I read here that the panel members didn’t even realize that they were originally charged with answering these questions. When Von Storch began listing his answers to these questions at the panel meeting, someone tried to cut him off by saying that these questions were outside the scope of the panel’s study.

    Steve:
    The mandate of the NAS panel was quite trickily constructed and your observation about von Storch is correct. If you go to the NAS panel categrory and scroll back, there are some contemporary accounts of this.

  124. Posted Nov 9, 2007 at 11:09 PM | Permalink | Reply

    My quote above was from Richard Smith’s account of the 2006 American Statistical Association session here.

  125. mccall
    Posted Nov 10, 2007 at 5:15 AM | Permalink | Reply

    Mr McIntyre or other, please help -

    I (and perhaps others) have confusion regarding
    1) Wahl & Ammann (2007) … retry of #2 is still unpublished (& not yet accepted)
    2) Wahl and Ammann (2006) … unpublished (never published, now withdrawn)
    3) Wahl, Eugene R.; Ritson, David M. & Ammann, Caspar M. (2006), “Comment on “Reconstructing Past Climate from Noisy Data”

    Is this correct?

    Steve:
    Of the two submissions, the one to Climatic Change (now Wahl and Ammann 2007) was accepted. It included references to Ammann and Wahl (submitted, GRL) which was rejected. Although Wahl and Ammann 2007 was supposedly accepted on Feb 28, 2006, it was not published even online until August 2007, during which time another paper Ammann and Wahl 2007 (Clim Chg) was accepted (said implausibly to have been submitted in 2000) – presumably a typo. The references in Wahl and Ammann to Ammann and Wahl (submitted) were re-cast to the other Clim Chg submission Ammann and Wahl – all clear now?

  126. mccall
    Posted Nov 10, 2007 at 5:17 AM | Permalink | Reply

    Correction:
    2) Wahl and Ammann (2006) … unpublished (initially accepted, then rejected, and now withdrawn)

    Is this correct?

  127. steven mosher
    Posted Nov 10, 2007 at 9:20 AM | Permalink | Reply

    RE 122.

    You got them both.

  128. Peter D. Tillman
    Posted Nov 13, 2007 at 2:27 PM | Permalink | Reply

    Re #94 Carl Gullans

    I also like the idea of a summary wiki for newcomers, and volunteer to work on it.

    KS, all posts: It would be worth your while to read the recent David Holland paper, referenced at http://www.climateaudit.org/?p=2326
    His tone is a little shrill, but he goes over the arguments quite thoroughly.

    Another outside source that’s worth a look is Hans Storch, http://blogs.nature.com/climatefeedback/2007/05/the_decay_of_the_hockey_stick.html
    and the comment thread.

    Cheers — Pete Tillman

  129. Alex Harvey
    Posted Jan 28, 2008 at 7:34 AM | Permalink | Reply

    hi,

    I’m new here & I must admit I’m a layperson with no technical training other than a degree in philosophy of science. For several months my head has been spinning left & right trying to understand this debate.

    What I’ve just read in this thread is fascinating. However it seems to me that a point ks raises in #7 isn’t properly answered. “It doesn’t mean Dr. Mann’s conclusions are wrong.”

    Wegman writes:

    A number of other commentators have acknowledged the flaws in the Mann reconstruction but have argued that this does not matter because the answers have been verified by other analyses. Ed’s own response to that was given in the equation:

    Method Wrong + Answer Correct = Bad Science.

    In other words, the fact that the answer may have been correct does not justify the use of an incorrect method in the first place.

    I can see that Dr. Wegman is unimpressed as a scientist that this ‘Bad Science’ ever happened. However Wegman nevertheless says ‘Answer Correct’ right? Is not this the bottom line as far as the use of Wegman’s name in this controversy should go?

    However others in this thread seem to have rejoined, “But where there is ‘Bad Science’ who can really say that there is ‘Answer Correct’?” Now that’s fine and I’m somewhat persuaded by that argument. But the point seems to remain that the balance of evidence (other truly independent studies — i.e. independent in the way that Wahl & Ammann is apparently not?) seems to have convinced Wegman that there is an ‘Answer Correct’ in MBH98. And since Mann himself seems to have conceded at RC that “we all make mistakes” and that, ahem, there may have been some ‘Bad Science’ — is it fair to be using Wegman’s name to support the contention that “all hockey-sticks have been refuted”?

    Thanks in advance to anyone with time to answer!
    Alex Harvey

  130. Larry Huldén
    Posted Jan 28, 2008 at 8:16 AM | Permalink | Reply

    Wegman confirmed Steve McIntyre’s observations about Manns errors in calculations and he has also confirmed that “other independent results” are not independent. They use practically the same data and in most cases also the same incorrect methods to show that there has been practically no variation in mean temperatures before 1850, with a strong rise from 1850 – about 2000.
    The error in calculations are based on weighting of two or three questionable tree ring series which show a rise after 1850 by a factor of several hundred in comparison with all the others. By this method the other series will cancel out so the result is a “straight line” before 1850.
    From really independent sources we know now that there has been considerable variation in mean temperatures.

  131. Greg F
    Posted Jan 28, 2008 at 9:06 AM | Permalink | Reply

    However Wegman nevertheless says ‘Answer Correct’ right?

    No.

    But the point seems to remain that the balance of evidence (other truly independent studies — i.e. independent in the way that Wahl & Ammann is apparently not?) seems to have convinced Wegman that there is an ‘Answer Correct’ in MBH98.

    I think you have read more into Wegman then is there. He didn’t conclude that the answer was right or wrong, it is not his expertise. He is quoted as saying:

    I am baffled by the claim that the incorrect method doesn’t matter because the answer is correct anyway. Method Wrong + Answer Correct = Bad Science.

  132. Ross McKitrick
    Posted Jan 28, 2008 at 10:47 AM | Permalink | Reply

    Wegman was not saying that the answer was correct. On that point his conclusion was that the data and analysis did not support the conclusions that had been drawn, and the independent evidence cited in its favour was not independent at all–the data sets were full of repeated series and the authors were too interconnected. He was presenting this as a stylized version of what other people were arguing: sure the method was wrong, but the answer is correct anyway. I.e. Fake but accurate. Wegman’s reply was, sorry but even if the answer were correct it would be a wierd science where the answers are always correct even if you do the calculations wrong.

  133. Larry
    Posted Jan 28, 2008 at 11:12 AM | Permalink | Reply

    Did I miss something, or is Mann’s argument circular? If I understand this correctly, he’s saying that the bad method is irrelevant, because the answer is right. But is there any truly independent evidence that he’s right? Or is this exactly a case like Dan Rather claiming that evidence is irrelevant because everybody knows that the answer is right even if it can’t be proven?

  134. Posted Jan 28, 2008 at 1:41 PM | Permalink | Reply

    Alex Harvey (#129) writes,

    Wegman writes:

    A number of other commentators have acknowledged the flaws in the Mann reconstruction but have argued that this does not matter because the answers have been verified by other analyses. Ed’s own response to that was given in the equation:

    Method Wrong + Answer Correct = Bad Science.

    ….

    I can see that Dr. Wegman is unimpressed as a scientist that this ‘Bad Science’ ever happened. However Wegman nevertheless says ‘Answer Correct’ right?

    I’d read him as saying in effect that even if the answer were correct, using a bad method to support it is bad science. If it turns out that there is no good method supporting a particular conclusion, then that conclusion is unsubstantiated. But Wegman isn’t judging this particular conclusion, just Mann’s method.

  135. Sam Urbinto
    Posted Jan 28, 2008 at 3:46 PM | Permalink | Reply

    I take it more as “Even if the answer is correct, there is no way to tell because the method doesn’t support the conclusions. It’s done incorrectly and the “independent verification” isn’t independent and doesn’t verify it.”

  136. Alex Harvey
    Posted Jan 28, 2008 at 9:00 PM | Permalink | Reply

    Well thanks for these responses although I’m still not convinced.

    Quoting Wegman in the reply to Stupak (2006):

    “Our report does not prove that the hockey stick disappears. Our work demonstrates that the methodology is incorrect. Because of the lack of proper statistical sampling and correct inferential methodology, we concluded that the statements regarding the decade of the 1990s probably being the hottest in a millennium and 1998 probably being the hottest year in a millennium are unwarranted. Indeed, I repeatedly testified that the instrumented temperature record from 1850 onwards indicated that there is a pattern of global warming. We have never disputed this. We also believe that there is no dispute between our report and the North report in this regard. Professor North in testimony agreed with our conclusions regarding the incorrectness of the methodology. We in turn agree with the fundamental conclusion of the North report, i.e. that the present era is likely the hottest in the last 400 years. We remain silent on the issues related to anthropogenic global warming.”

    And comparing this with IPCC 2007:

    “The weight of current multi-proxy evidence, therefore, suggests greater 20th-century warmth, in comparison with temperature levels of the previous 400 years, than was shown in the TAR. On the evidence of the previous and four new reconstructions that reach back more than 1 kyr, it is likely that the 20th century was the warmest in at least the past 1.3 kyr. Considering the recent instrumental and longer proxy evidence together, it is very likely that average NH temperatures during the second half of the 20th century were higher than for any other 50-year period in the last 500 years. Greater uncertainty associated with proxy-based temperature estimates for individual years means that it is more difficult to gauge the significance, or precedence, of the extreme warm years observed in the recent instrumental record, such as 1998 and 2005, in the context of the last millennium.”

    So, again, where is the conflict between Wegman’s (& North’s) positions and that of IPCC 2007? Why should one be skeptical of the AGW theory? Aren’t we just quibbling over detail in arguing “contra Mann et al. the MWP may in fact have been warmer than the late 20th century”?

    Thanks again,
    Alex

  137. Raven
    Posted Jan 28, 2008 at 9:37 PM | Permalink | Reply

    Alex Harvey says:

    So, again, where is the conflict between Wegman’s (& North’s) positions and that of IPCC 2007? Why should one be skeptical of the AGW theory? Aren’t we just quibbling over detail in arguing “contra Mann et al. the MWP may in fact have been warmer than the late 20th century”?

    It comes down to this:

    Mann produced a study which was complete rubbish.
    The IPCC and the peer review process did not figure this out (probably because the result suited their agenda).
    Other climate scientists produced ‘peer reviewed’ papers that repeat Mann’s rubbish and refuse to acknowledge the fundamental flaws in Mann’s work.
    The IPCC continues to use the Mann data or its derivatives such as Briffa despite the fact that it has been shown to be rubbish.

    For me the entire episode demonstrates that no one should accept something as true because the IPCC and/or ‘climate scientists’ said its true.

    Once I dispensed with the the notion that the IPCC is infallible and started to look critically at their science I found that a lot of the science is built on dubious assumptions and an uncertain data. None of this means that the IPCC and the consensus is wrong – but it does mean the science is not as certain as alarmists would like us to believe.

    That said, picking at the theory would not mean much if the actual data supported the AGW hypothesis. However, the actual data suggests that the AGW alarmists have consistently over estimated the effect of CO2 induced warming. This mismatch between predictions and reality tells me that we should be very cautious before we implement radical social changes based on AGW science.

  138. eric mcfarland
    Posted Jan 28, 2008 at 9:43 PM | Permalink | Reply

    137: I still have not seen the big expose that shows that Mann’s stuff is actually rubbish after all. THE WSJ got fired up at first … but got quiet when the ambush did not produce a body. Sorry Steve!

  139. Tom C
    Posted Jan 28, 2008 at 9:44 PM | Permalink | Reply

    #136 Alex Harvey

    The issue is not whether it has been warming for the last 400 years. Everyone knows that and it is not controversial. There is, after all, a reason that the “Little Ice Age” of 400 years ago was thus named. What the “Hockey Stick” tried to do was erase the Medieval Warm Period for the political purpose of making the present warming appear to be a crisis. The North and Wegman reports both say that erasing the MWP is not justified by the data and analysis.

    You should read the “Wegman Reply to Stupak” and Ross KcKitrick’s summary in the links on the left side of the page.

  140. Raven
    Posted Jan 28, 2008 at 10:01 PM | Permalink | Reply

    eric mcfarland says:

    137: I still have not seen the big expose that shows that Mann’s stuff is actually rubbish after all. THE WSJ got fired up at first … but got quiet when the ambush did not produce a body. Sorry Steve!

    The material is explained on this blog. If you choose to deny the evidence it then that it your problem. This seems to be Steve’s most recent comments on Mann’s attempt to resurrect the Hockey Stick: http://www.climateaudit.org/?p=2421#more-2421

  141. eric mcfarland
    Posted Jan 28, 2008 at 10:05 PM | Permalink | Reply

    Thanks Raven. As for the MWP … does anybody actually know how warm it was or how widespread?

  142. eric mcfarland
    Posted Jan 28, 2008 at 10:13 PM | Permalink | Reply

    I’ve got a song for Raven:

  143. J. Peden
    Posted Jan 29, 2008 at 12:35 AM | Permalink | Reply

    Alex Harvey: “So, again, where is the conflict between Wegman’s (& North’s) positions and that of IPCC 2007.”

    In your comparative quotes, Wegman was not talking about the ipcc’s “four new reconstructions”, so there can’t possibly be any conflict between his and the ipcc’s statement relating to the MWP – unless perhaps the ipcc’s “previous” refers to Mann’s study.

    Ideally, the topic of this thread is whether Wegman and North dispute M&M’s critique of Mann’s Hockey Stick derivation. They seem to support the critique, don’t they?

  144. Alex Harvey
    Posted Jan 29, 2008 at 2:15 AM | Permalink | Reply

    Tom C. (#139):

    Thanks for clarification & reference to Ross M.’s article. Actually, it’s a very good read.

    If I may summarise, then, MM’s refutation of MBH98 & MBH99 appears to stand — Wegman, North & apparently IPCC 2007 as well all concur. Mann et al. have had been exposed as poor mathematicians & the IPCC review process as well as the peer review processes of the journals which published MBH98 & MBH99 have been found wanting.snipThe issue of the IPCC’s breach of trust in not picking up the hockey-stick flaws in IPCC 2001 is raised although Wegman’s tone is more moderate.

    Meanwhile, though, none of this bears on the AGW theory itself which holds true whether the MWP was warmer than today or otherwise. What we’ve seen is that in the past there has been an apparent spin applied to the theory to hide the possible fact that nature herself can cause global warming even greater than what humans today are causing. It’s possible that in so hiding this fact — intentionally or otherwise — governments did agree to act at Kyoto.

    Is this a fair summary?

  145. Alex Harvey
    Posted Jan 29, 2008 at 4:53 AM | Permalink | Reply

    Further to this post it occurred to me that a lot of the confusion in this controversy seems to arise in the fact that MM are not claiming that their refutation of MBH98 & MBH99 implies that “therefore, on the contrary, the MWP was hotter than today” but only that “it is therefore unknown whether the MWP was hotter or colder than today.” Is this right?

  146. ourphyl
    Posted Jan 29, 2008 at 5:14 AM | Permalink | Reply

    Alex Harvey (#144):

    …Is this a fair summary?

    Not completely. It helps establish the AGW policy issues as different and separate from the “bad science” issues, an important first step if our objective is to make progress. It correctly points out that the “hockey stick” was (is?) a Public Relations problem but it should also stress that it’s only our own failures to cope with such PR policy problems that makes HS seem to be a “scientific” problem exacerbated by poor IPCC administration.

    Climate science is, at best, a very new field. A merger of at least a half dozen disciplines, it must try to cope with a variety of processes, vocabularies, and methodologies employed by earth, atmosphere, and ocean investigators. Non-practitioners really are quite arrogant to believe they can structure the operation and administration of this new activity better than those attempting to make their living inventing this new “science”.

    Ascribing personal motivations to explain an activity is an error-prone and unscientific activity – even when no other reasoning seems capable of dealing with it. As they say, “When you’re up to your a$$ in alligators, it’s easy to forget that your objective was to drain the swamp.” If you want to move the science ball forward, it would be better to join the hockey team and try to solve some of their problems, than to berate their failure to do the work the best way.

    I’ve read a lot here about statistics and Dr. Edward Wegman. In addition to his committee’s report mentioned over and over again here and elsewhere, he has made it clear that he does not believe that AGW is real. The board of directors of his American Statistical Association (ASA) don’t agree. They also don’t blame the climate scientists for any lack of “good” statistics in climate change science, quite correctly, they blame the professional statisticians. Last November, when they endorsed the IPCC IV conclusions, they pointed with pride to a small number of their members who had contributed to this work and suggested that more of their members apply their expertise to work on the same problems that skeptics leave to the climate scientists. They see Ed Wegman’s climate change glass as half full, not half empty. listen to them here

    Obviously, the above is only my opinion and I am still a newbee at that. Still, I believe that if you don’t believe AGW is an important problem, leave the hockey team alone to pursue their quests. OTOH, if you think it’s important, try to help them out.

    john

  147. MarkW
    Posted Jan 29, 2008 at 5:35 AM | Permalink | Reply

    Part of the problem with the IPCC, is that they used the hockey stick, and that particular section was written by Mann himself.

  148. MarkW
    Posted Jan 29, 2008 at 5:43 AM | Permalink | Reply

    Only those who are currently engaged in client science study are qualified to judge whether the science being used is any good????

    And you accuse others of arrogance?

    Still, I believe that if you don’t believe AGW is an important problem, leave the hockey team alone to pursue their quests.

    If you don’t believe that cars are safe, just leave the auto companies alone to continue building their product.
    If you don’t believe that planes are safe, just leave Boing alone to build better planes.

    If the hockey team was content to leave me alone, I would be quite content to ignore them while they perfect this “new” science of theirs.
    The hockey team is not content to leave me alone. They want the govts of the world to radically change the way I live my life, and not for the better.

    Since they have choosen to enter the realm of policy, they open themselves up to all of these critiques.

  149. Hans Erren
    Posted Jan 29, 2008 at 5:45 AM | Permalink | Reply

    Climate science as a whole is still in the storming phase of group development.
    http://en.wikipedia.org/wiki/Forming-storming-norming-performing

    The extremes have already reached groupthink: “The end is near” and “Global warming is a myth”

  150. kim
    Posted Jan 29, 2008 at 5:46 AM | Permalink | Reply

    I sat in the comment section of the Stan Palmer thread at Pharyngula for around 40 hours and untold comments, and got one scientist to consider the problem of diversion.
    ==================================

  151. kim
    Posted Jan 29, 2008 at 8:36 AM | Permalink | Reply

    uh, divergence.
    =========

  152. Mark T.
    Posted Jan 29, 2008 at 10:47 AM | Permalink | Reply

    OTOH, if you think it’s important, try to help them out.

    The point I think you miss with this statement is that audit as provided by the likes of Steve M. does indeed help the team out. However, helping them out does not mean the results should necessarily bolster their argument, it simply means it advances science by providing a key element of the scientific method. Audit advances science in a very critical way: falsification. The team members have not done their own due diligence, which stagnates science, and hence, such an effort by outsiders (so to speak) is required.

    Mark

  153. Tom C
    Posted Jan 29, 2008 at 1:19 PM | Permalink | Reply

    #144, 145 Alex Harvey

    I think you got it about right in your summaries. The scientific conclusions that can be drawn from the Hockey stick debunking are very modest. The real importance was how it exposed the corruption of the IPCC and Mann by virtue of all the dissembling and obstruction.

    In regard to the MWP, there are numerous lines of evidence that point to very warm temperatures worldwide. I trust qualitative historical accounts much more than results from proxy measurements, most of which involve many layers of substantial error.

  154. J. Peden
    Posted Jan 29, 2008 at 1:22 PM | Permalink | Reply

    ourphyl: Non-practitioners really are quite arrogant to believe they can structure the operation and administration of this new activity better than those attempting to make their living inventing this new “science”.

    That’s fine as a statement about the right of entrepreneurs to form a business and profit from it. But the question still standing – and, I believe, answered by this thread – as regards the scientific process of Peer Review, is whether Wegman and North dispute/support M&M’s critique of Mann’s derivation of his study’s Hockey Stick.

  155. Sam Urbinto
    Posted Jan 29, 2008 at 3:08 PM | Permalink | Reply

    The issue here is the testimony has a lot of pro-anti AGW debate and agenda type questions from the politicians, with various answers depending on the person and their outlook. What’s not under contention is, regarding MBH98/99: ‘some of the methodology choices were inapprorpriate’

    Dr. Wegman spells out what he was asked to do, which was to independently veryify the critiques of MM03/05a/05b and to consider and report on the implications. Or as he says at one point he says “…my report was very specific on a very specific issue that was asked of me and we answered that very specific question.” Are the critiques valid or not? What are the implications of that answer?

    “…my report was very specific on a very specific issue that was asked of me and we answered that very specific question.”

    We were not asked to assess the reality of global warming and indeed this is not an area of our expertise. We do not assume any position with respect to global warming except to note in our report that the instrumented record of global average temperature has risen since 1850 according to the MBH99 chart by about 1.2 degrees Centigrade, and in the NAS panel report chaired by Dr. North, about six-tenths of a degree Centigrade in several places in that report.

    At one point where Ms. Schakowsky is asking “questions”, Dr. Wegman basically says:

    I’m not going to comment on carbon dioxide and temperature, I don’t know “the truth”. Not my area, has no bearing on what I was asked to investigate. But my report doesn’t disprove climate change isn’t at least partially manmade, no. And nobody should infer that using the wrong methodology makes all the facts wrong. I’m saying that when something has incorrect methods, that thing should be discarded as a policy tool. The methods are not correct, and those using them should find a better approach and not continue to defend using them. I have no position on papers that don’t use this flawed principal component methodology. I hope I’ve made that clear. Now, go do science!

    Read the full “Barton panel” text.

    As far as the IPCC graphs, simply used as an example:

    To illustrate this {centering issues}, we consider the North America Tree series and apply the MBH98 methodology. The top panel shows the result from the de-centering. The bottom panel shows the result when the principal components are properly centered. Thus the centering does make a significant difference to the reconstruction.

    To further illustrate this, we digitized the temperature profile published in the IPCC 1990 report and applied both the CFR and the CPS methods to them. The data used here are 69 unstructured noise pseudo-proxy series and only one copy of the 1990 profile. The upper left panel illustrates the PC1 with proper centering. In other words, no structure is shown. The other 3 panels indicate what happens using principal components with an increasing amount of de-centering. Again, the single series begins to overwhelm the other 69 pure noise series. Clearly, these have a big effect.

    It is not clear that Mann and associates realized the error in their methodology at the time of publication. Our re-creation supports the critique of the MBH98 methods.

    Or as Dr. North put it:

    Our main disagreements with the Mann 98/99 papers are related to the assertions about warmth of individual decades and individual years. We don’t subscribe to that kind of definition of the problem. We also question some of their statistical methodology, in fact, some of the same claims that were put forward by Dr. Wegman and you will hear some later as well.

    Based upon all this, the only conclusion is that MBH98/99 doesn’t suport the claim of when it was the “hottest” in the last 1000 years.

    Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

  156. Sam Urbinto
    Posted Jan 29, 2008 at 4:13 PM | Permalink | Reply

    That should have been ‘by’.

    Independently verify (and therefore validate or invalidate) the critiques by MM03/05a/05b of MBH98/99 and to consider and report on the implications of the findings.

    So what did the statisticians say?

    ‘Some of the methodology choices were inappropriate.’
    ‘We also question some of their statistical methodology.’
    ‘Our re-creation supports the critique of the MBH98 methods.’

  157. Posted Jan 29, 2008 at 4:21 PM | Permalink | Reply

    Based upon all this, the only conclusion is that MBH98/99 doesn’t suport the claim of when it was the “hottest” in the last 1000 years.

    i am very glad, that the Loehle paper settled this issue:

    we are living in the hottest period over the last 1000 years..

  158. ourphyl
    Posted Jan 29, 2008 at 4:32 PM | Permalink | Reply

    MarkW (#147)

    Part of the problem with the IPCC,

    IPCC is not a scientific organization, it is a political subdivision of the United Nations. Mann and other scientists like him have no control and little influence over UN actions (think “oil for food”).

    is that they used the hockey stick and that particular section was written by Mann himself.

    I believe Mann was a TAR lead author, responsible for TAR section 2. He probably wrote most of sections 2.2 and 2.3.

    a) For every 100 people criticizing Mann’s TAR writings, 99 most probably have never read any of them. Try section 2.3.2.2 or section 2.3.2.3 for starters.

    b) I am trained in and have practiced science for many years. I consider the above sections to be full scientific disclosure by Mann and other IPCC scientists of the assumptions and the uncertainities surrounding figures 2.20 and 2.21 based on their knowledge at that time . I would welcome specific corrections from any scientist who disagrees with me here.

    (#148)

    Only those who are currently engaged in client science study are qualified to judge whether the science being used is any good????

    yup

    And you accuse others of arrogance?

    yup. (I always say that it takes one to know one. Most probably then, your conclusion about my arrogance is a correct one.)

    If the hockey team was content to leave me alone, I would be quite content to ignore them while they perfect this “new” science of theirs. The hockey team is not content to leave me alone. They want, the govts of the world to radically change the way I live my life, and not for the better.

    Like Steve, your problem seems to be with the govts, not the hockey team.

    Remember I am a newbe to climate science, even though I have a lot of experience with science and am probably too arrogant,

    cheers,

    j

  159. Raven
    Posted Jan 29, 2008 at 5:06 PM | Permalink | Reply

    ourphyl says:

    a) For every 100 people criticizing Mann’s TAR writings, 99 most probably have never read any of them.

    I don’t see why you think that constitutes an argument. Mann’s work has been reviewed carefully by people skilled with stats and found to have serious flaws – flaws that cannot be explained away by disclosure of the ‘assumptions and the uncertainities’ surrounding his conclusions.

    The offical rebuke of Mann’s work tries to be polite by stating that his conclusions are not supported by the data yet you appear to make the mistake of believing that is simply a matter of uncertainty intervals. It is not – Mann took a signal which was no better than random noise and manipulated it to produce a graph that suited his views. This would be scientific fraud if it could be shown that the errors were deliberate rather than ignorance and confirmation bias (I suspect the latter).

    That said, Mann is just one individual and his errors would have been inconsequential if the IPCC/climate science community had acknowledged and learned from Mann’s errors. Unfortunately, they circled the wagons and defended the indefensible.

    To make matter worse there are still ‘climate scientists’ such as yourself who choose to ignore the legimate issues raised and demand that lesser mortals accept your pronouncements without question because you are a ‘climate scientist’ and they are not. Why should they?

  160. Dave Dardinger
    Posted Jan 29, 2008 at 5:09 PM | Permalink | Reply

    re: #158 Ourphyl,

    If you think section 2.3.2.2 is correct, you’re obviously a newbee here. And if you think the active posters here haven’t read it and discussed it to death, you’re just plain wrong. Now Mann et. al. may have believed the results there were correct, based on their studies, but the studies were all flawed by relying on a few proxy series which are not good temperature proxies or have other problems. Every single paper mentioned there has had threads here and you can find them with no trouble (see left margin for links). Read them and perhaps your unwarrented arrogance will be reduced.

  161. David Holland
    Posted Jan 29, 2008 at 5:25 PM | Permalink | Reply

    Re #155 Sam,
    I think the NRC report says more than just Mann can’t support the “warmest year” claim. On page 110 it says, “Largescale temperature reconstructions should always be viewed as having a “murky” early period and a later period of relative clarity. The boundary between murkiness and clarity is not precise but is nominally around A.D. 1600.” It also says on page 107 “Some of these criticisms are more relevant than others, but taken together, they are an important aspect of a more general finding of this committee, which is that uncertainties of the published reconstructions have been underestimated.”

    They do say its “plausible” that it is now warmer than the MWP but the IPCC AR4 turned that into “likely”. The problem with AGW theory is that if it was ever warmer with lower GHG, “tipping” point theory looks unlikely and natural variation from whatever source is more significant than is currently allowed for. The problem is exactly as the First IPCC Assessment says – without understanding past warming we can’t say what role GHG have. This also applies to the Little Ice Age which Mann also eliminated.

    Is there a climate model that can replicate the coldest LIA that AR4 shows and still fit 20th century? The bore hole data shows about 0.4C rise from 1500 to 1850 when CO2 was supposed to be pretty constant.

  162. ourphyl
    Posted Jan 29, 2008 at 5:35 PM | Permalink | Reply

    MarkT (#152)

    I believe MM pointing out data errors so that Mann et al could fix them was helpful criticism by the skeptics. Critique of the team’s implementation of PC methodology could also have been helpful.

    Delivering these gifts five years too late in the form of an inquisition was not helpful. Insisting that the MM discoveries invalidated the warmest since…(you fill in a date) claim is not only not helpful, it is incorrect. (NAS and SAS have set this much straight, Wegman still refuses to.) Continuing to flog these dead horses ten years later is at best, childish. All it has done so far is to help Mann get promoted.

    Steve (and others) can’t audit because no one knows any climate temperature data, in the past or in the future, that is scientifically correct. So there’s nothing to audit against. Let those who are in it for the science (knowledge) continue their search. Let those more interested in politics (action) find some other way than using “scientific climate data”. At least until climate scientists come through with some better answers.

    I agree that science requires skepticism and skeptics to advance. I believe it would help if we could get through this storming phase and concentrate on more scientific skepticism.

    cheers

    j

  163. J. Peden
    Posted Jan 29, 2008 at 6:15 PM | Permalink | Reply

    question:Only those who are currently engaged in client ["climate", I presume] science study are qualified to judge whether the science being used is any good????

    ourphyl: “yup”

    ourphyl, I believe you have just disqualified yourself as to your ability to comment upon the question of whether the science being used by climate scientists is any good – since you also admit you are a newbie to the climate science field. So be it.

    Meanwhile, back in the world of well established scientific practices, the rest of us are looking at a Peer Review of M&M’s critique of Mann’s Hockey Stick derivation, which agrees with that critique. Moreover, despite the ipcc’s ~”full disclosure of known assumptions and uncertainties” it appears that Mann’s derivation was never Peer Reviewed by anyone associated with the ipcc – that is, until M&M actually did it.

    I’ll stick with the established scientific practices, and my own ability to recognize them.

  164. David Holland
    Posted Jan 29, 2008 at 6:26 PM | Permalink | Reply

    I think you can come up another equation:
    Science OK + Process Bad = Unreliable Answer

    We expect our police, courts and governments to follow the rules so why do think an IPCC which ignores the internationally agreed principles governing its work is going to be reliable.

    WGI TSU have kindly sent me a copy of one of the Review Editors Reports on Chapter 6. This is the nearest we taxpayers get to an audit or QA report. It was faxed by Dr John Mitchell to TSU 11th Dec 2006 so Steve might like to check when he had asked for it. I have transcribed it and this is all he says,

    As Review Editor of Chapter 6 Paleoclimate of the Working Group I contribution to the IPCC Fourth Assessment Report, “Climate Change 2007: The Physical Basis”, I can confirm that the authors have in my view dealt with reviewers comments to the extent that can be reasonably expected. There will inevitably remain some disagreement on how they have dealt with the reconstructions of the last 1000 years, and there is further work to do here in the future, but in my judgement, the authors have made a reasonable assessment of the evidence they have to hand. The other possible area of contention (within the author team) is on some aspects of sea level rise – this has gone some way towards reconciliation but I sense not everyone is entirely happy.

    With these caveats I am happy to sign off the chapter, to thank the lead author team for their cooperation, and congratulate them on the chapter.

    “To the extent that can be reasonably expected” may be literally true considering the known views of the lead authors but if you look at the “rules” as shown on the IPCC website he could not have signed it off as in conformance with them. The rules say:

    Review Editors will assist the Working Group/Task Force Bureaux in identifying reviewers for the expert review process, ensure that all substantive expert and government review comments are afforded appropriate consideration, advise lead authors on how to handle contentious/controversial issues and ensure genuine controversies are reflected adequately in the text of the Report.

    The inadequate 18-line dismissal of M&M and the inclusion of W&A against the clear objections of the Reviewer for the Govt of the US tell me the Review Editors did not do their job on chapter 6.

  165. Mark T.
    Posted Jan 29, 2008 at 6:35 PM | Permalink | Reply

    Delivering these gifts five years too late in the form of an inquisition was not helpful.

    Steve M. did not create the inquisition, and the fact that Mann continues to defend the indefensible is his fault, not Steve’s.

    Insisting that the MM discoveries invalidated the warmest since…(you fill in a date) claim is not only not helpful, it is incorrect.

    Nobody is insisting anything (re: thread topic) other than the simple fact that Mann’s conclusions about the past millenia cannot be supported by the evidence he has presented. So no, sir, not incorrect.

    (NAS and SAS have set this much straight, Wegman still refuses to.)

    Wegman meerely stated that Mann’s conclusions cannot be supported by his evidence. Nothing more, nothing less, and the NAS agrees. Yet still here we are with paper after paper coming from members of the team defending what is known to be wrong.

    Continuing to flog these dead horses ten years later is at best, childish.

    Are you making the same assertions every time Mann gets another paper published which makes the same simple, and now egregious, errors? The same horses need to be repeatedly flogged because the team keeps putting them into the race. Again, team’s fault, not Steve’s.

    Steve (and others) can’t audit because no one knows any climate temperature data, in the past or in the future, that is scientifically correct. So there’s nothing to audit against.

    Nonsense, the team keeps publishing papers, and Steve keeps auditing.

    Let those who are in it for the science (knowledge) continue their search. Let those more interested in politics (action) find some other way than using “scientific climate data”. At least until climate scientists come through with some better answers.

    The problem, again, is that the climate scientists in question refuse to admit and correct their mistakes, and thus we are left to keep “proving” what has already been proved. It is tiring.

    I agree that science requires skepticism and skeptics to advance. I believe it would help if we could get through this storming phase and concentrate on more scientific skepticism.

    Sure enough…

    Mark

  166. ourphyl
    Posted Jan 29, 2008 at 6:51 PM | Permalink | Reply

    J. Peden (#154)

    Thanks for your thoughtful response.

    That’s fine as a statement about the right of entrepreneurs to form a business and profit from it.

    Well at least we agree about that much.

    But the question still standing – and, I believe, answered by this thread – as regards the scientific process of Peer Review,

    I Disagree. As Mann points out what did Wegman(‘s committee) or any one else know about the specific peer reviews of any specific papers. Editors do not reveal the ids of reviewers. Period.

    Wegman misleads, he had no data. He did have marvelous graphics though.

    … is whether Wegman and North dispute/support M&M’s critique of Mann’s derivation of his study’s Hockey Stick.

    No disagreement here, if you limit yourself to MBH98/99 and MM05a and MM05b. Everyone agrees that Mann used faulty PCA methodology and that Steve and Rob were right to point that out. But that is the extent of the NAS, ASA agreement re MM.

    Any disagreement is over whether or not Mann’s mistake mattered much. This thread is not because of these (4 or 5) papers, it is over whatever Mann did or did not do as lead author of chapter 2 of TAR. Some say he used his own work, that’s not what the final report shows. As I tried to display in #158, his writings for TAR were considered, complete and as scientific as Climate Science can be. As far as I am concerned all other representations as to what Mann did or did not do, re IPCC TAR are little more than gossip.

    cheers,

    j

  167. SteveSadlov
    Posted Jan 29, 2008 at 6:58 PM | Permalink | Reply

    To Eric the NRDC Cheerleader: The hockey stick needed BCPs, and was augmented by some other “agreeable” proxies. BCPs are not a temperature proxy and the other “agreeable” ones are either not enough to create a hockey stick or are not demonstrated temperature proxies. Add to that a Mannomatic “algorithm” that takes any hockeystickedness of any conmponent, and outputs a hockey stick as the “combination” of the components. Money quote: “We need to eliminate the MWP.” Mann and his team mates are garbage men.

  168. J. Peden
    Posted Jan 29, 2008 at 8:01 PM | Permalink | Reply

    ourphyl: As Mann points out what did Wegman(‘s committee) or any one else know about the [ipcc's] specific peer reviews of any specific papers.

    So just what “specific peer reviews” of Mann’s derivation of his Hockey Stick are in the ipcc’s Black Box – the ones which help substantiate your assertion that, Everyone agrees that Mann used faulty PCA methodology….?

    Or is there nothing in the Box?

    Regardless, you’ve already conceeded that such issues don’t matter much to you, since you think climate science has no necessary connection to established science. Once again, so be it.

  169. ourphyl
    Posted Jan 29, 2008 at 8:17 PM | Permalink | Reply

    Sam Urbinto (#155/156)

    Thanks Sam, AFAIAC you’ve pretty much nailed down what Wegman found and said. I have no disagreement with you there.

    I agree with Wegman if he says

    “…I’m saying that when something has incorrect methods, that thing should be discarded as a policy tool. The methods are not correct, and those using them as a policy tool. should find a better approach and not continue to defend using them as a policy tool. My added emphthasis.

    I disagree with Wegman when he tells us to go “do science” with some unknown methodology and unknown data sources – in our day we called that “go pound sand”.

    I find the position statement of the group Wegman formerly headed up much more helpful. ASA Director’s statement including such statements of assistance as

    Through a series of meetings spanning several years, IPCC drew in leading experts and assessed the relevant literature in the geosciences and related disciplines as it relates to climate change. The Fourth Assessment Report finds that “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising mean sea level. … Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. … Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes, and wind patterns The ASA endorses the IPCC conclusions

    and recognition of the difficulties

    …Even in the satellite era – the best observed period in Earth’s climate history – there are significant uncertainties in key observational datasets. Reduction of these uncertainties will be crucial for evaluating and better constraining climate models. Statisticians can advise on how best to combine data from different sources, how to identify and adjust for biases in different measurement systems, and how to deal with changes in the spatial and temporal coverage of measurements. The climate science community often requires regular fields of geophysical variables, such as surface temperature, which must be derived from irregular and heterogeneous observations. Evaluating the advantages and disadvantages of different interpolation approaches (referred to as infilling in climate applications) could be very helpful. This research area contains many opportunities for the development and fitting of sophisticated space-time models to sparse data…

    Thanks again Sam, you’re very helpful.

    cheers,

    j

  170. ourphyl
    Posted Jan 29, 2008 at 8:43 PM | Permalink | Reply

    Raven (#159)

    Thanks, but I disagree. AFAICT “everyone” knows that “Mann’s methods are wrong”, OTOH no one knows how to do it right.

    Well, what do you know about that!

    cheers,

    j

  171. Alex Harvey
    Posted Jan 30, 2008 at 1:49 AM | Permalink | Reply

    Soe (#157):

    “i am very glad, that the Loehle paper settled this issue: we are living in the hottest period over the last 1000 years..”

    The discussions of a recent Loehle paper [2008?] (with Loehle himself contributing here at CA) seem to support the opposite view that the MWP was warmer than the present. Have I misunderstood this?

  172. Alex Harvey
    Posted Jan 30, 2008 at 1:56 AM | Permalink | Reply

    Would this thread also be a good place to discuss (or link to discussions of) Mann’s page at realclimate: “Myth vs. Fact Regarding the ‘Hockey Stick’” http://www.realclimate.org/index.php/archives/2004/12/myths-vs-fact-regarding-the-hockey-stick/ ?

  173. Posted Jan 30, 2008 at 5:00 AM | Permalink | Reply

    The discussions of a recent Loehle paper [2008?] (with Loehle himself contributing here at CA) seem to support the opposite view that the MWP was warmer than the present. Have I misunderstood this?

    the Loehle reconstruction is about 1935 years. the Mann graph is only 1000 years.

    if you only go back 1000 years, the Loehle reconstruction confirms the findings of Mann.

    that is because Loehle got a MWP before the year 1000.

  174. Posted Jan 30, 2008 at 5:38 AM | Permalink | Reply

    sod,

    if you only go back 1000 years, the Loehle reconstruction confirms the findings of Mann.

    I still need to fix Mann’s AD1000 step to make those recons match (a normal procedure in climate science ):

    http://www.climateaudit.org/?p=2380#comment-161991

    Give me some time. But that’s another story. It is very silly for the Team to spend their valuable time trying to protect Mann’s math. They have already lost that game.

  175. MarkW
    Posted Jan 30, 2008 at 5:44 AM | Permalink | Reply

    ourphyl:

    I guess that in your opinion, only people who design cars for a living are qualified to tell if a particular car will run or not.

    Additionally, one of the biggest questions revolves around whether the statistical methods used by the Team are appropriate, or even any good.
    Mann admits that he has little knowledge of statistics. People with professional degrees in statistics have reviewed Mann’s work, and found it wanting.
    Yet you declare that their reviews of statistics, must be ignored because they aren’t studying climate science???

    What is it about studying climate science that gives one a priviledged position in judging whether tree rings make appropriate climate proxies?
    What is it about studying climate science that gives one unique insite into whether ice cores make accurate temperature proxies?

    There is nothing “unique” about climate science. It is a mixture of many disciplines.

    Arrogance is tolerated when it is backed by a demonstrated expertise. You on the other hand can’t even demonstrate minimal competency.

  176. Peter Thompson
    Posted Jan 30, 2008 at 6:31 AM | Permalink | Reply

    sod #157

    “i am very glad, that the Loehle paper settled this issue:

    we are living in the hottest period over the last 1000 years..”

    sod, perhaps you should look at the Loehle paper before making such ridiculous claims.

    Loehle anomaly 1000 AD approximately +0.35 C

    Today’s instrumental record:
    UAH +0.11
    GISS +0.39
    RSS +0.08
    HadCRUT3 +0.21
    NCDC +0.40

    How is it again that you get from Loehle that we are living in the hottest period in 1000 years?

  177. Yorick
    Posted Jan 30, 2008 at 6:50 AM | Permalink | Reply

    sod pretty much thinks that if he makes the same dubious claim, over and over again, and believes it fervently enough, he will have made a convincing argument for the next guy. Rhetorical arguments are not going to settle the science, they count as a thinking certainly, but the goal is not understanding, it is conversion. Rhetorical arguments belong in the province of religion. Think about that sod.

  178. ourphyl
    Posted Jan 30, 2008 at 5:28 PM | Permalink | Reply

    J.Pedin (#168)

    IPCC peer-reviews and black boxes.

    I wasn’t trying to post anything at all about this (controversial) area.

    I support the efforts of Ross McKitrick et al. that produced the Independent Summary for Policymakers IPCC Fourth Assessment Report, the attempts by Fraser Institute to fund additional research in critical areas, and the technical group’s Overall Conclusions HERE

    you say:

    Regardless, you’ve already conceeded that such issues don’t matter much to you, since you think climate science has no necessary connection to established science. Once again, so be it.

    We could agree if you are willing to replace the stricken phrase by a long ways to go to become an

    cheers,
    John [just another technical guy trying to learn about Climate Science]

    Ross’s conclusions were:

    The following concluding statement is not in the Fourth Assessment Report, but was agreed upon by the ISPM writers based on their review of the current evidence. The Earth’s climate is an extremely complex system and we must not understate the difficulties involved in analyzing it. Despite the many data limitations and uncertainties, knowledge of the climate system continues to advance based on improved and expanding data sets and improved understanding of meteorological and oceanographic mechanisms.

    The climate in most places has undergone minor changes over the past 200 years, and the land-based surface temperature record of the past 100 years exhibits warming trends in many places. Measurement problems, including uneven sampling, missing data and local land-use changes, make interpretation of these trends difficult. Other, more stable data sets, such as satellite, radiosonde and ocean temperatures yield smaller warming trends. The actual climate change in many locations has been relatively small and within the range of known natural variability. There is no compelling evidence that dangerous or unprecedented changes are underway.

    The available data over the past century can be interpreted within the framework of a variety of hypotheses as to cause and mechanisms for the measured changes. The hypothesis that greenhouse gas emissions have produced or are capable of producing a significant warming of the Earth’s climate since the start of the industrial era is credible, and merits continued attention. However, the hypothesis cannot be proven by formal theoretical arguments, and the available data allow the hypothesis to be credibly disputed.

    Arguments for the hypothesis rely on computer simulations, which can never be decisive as supporting evidence. The computer models in use are not, by necessity, direct calculations of all basic physics but rely upon empirical approximations for many of the smaller scale processes of the oceans and atmosphere. They are tuned to produce a credible simulation of current global climate statistics, but this does not guarantee reliability in future climate regimes. And there are enough degrees of freedom in tunable models that simulations cannot serve as supporting evidence for any one tuning scheme, such as that associated with a strong effect from greenhouse gases.

    There is no evidence provided by the IPCC in its Fourth Assessment Report that the uncertainty can be formally resolved from first principles, statistical hypothesis testing or modeling exercises. Consequently, there will remain an unavoidable element of uncertainty as to the extent that humans are contributing to future climate change, and indeed whether or not such change is a good or bad thing.

  179. ourphyl
    Posted Jan 30, 2008 at 7:01 PM | Permalink | Reply

    MarkW (#175)

    I guess that in your opinion, only people who design cars for a living are qualified to tell if a particular car will run or not.

    That is definately not my opinion. I support testing and testing reports e.g. Customer Surveys, Consumer Reports, for a start. I support and use testing organizations (so called Product Test) for most of my work. I have found that testing requires very qualified, dedicated individuals, co-operative with, but independent of, designers and developers. My experience is that designers and developers usually do not make good testers. Designers should be skillful in how to make things. OTOH, testers should be skillful in how to break things.

    Additionally, one of the biggest questions revolves around whether the statistical methods used by the Team are appropriate, or even any good.

    I disagree. Statistical method or methods used in an established hard science should:

    1 – produce meaningful quantitative results

    2 – these quantified results should have quantifiable statistical confidence measures, e.g. sd, r2, skill, whatever.

    If and when Climate Science becomes such an established hard science, I would expect these same standards to be met. The team is trying very hard to such standards to their own work now.

    Mann admits that he has little knowledge of statistics. People with professional degrees in statistics have reviewed Mann’s work, and found it wanting. Yet you declare that their reviews of statistics, must be ignored because they aren’t studying climate science???

    Again I disagree. A key part of a climate scientist’s work is statistical in nature, and Mann’s PhD Thesis was heavily statistical. His PCA work was not “wanting”, he had overlooked a pecularity of PCA that MM found and Wegman believed would have been discovered had Mann had more experience. Mann had just graduated and Wegman believed MBH should have been reviewed by someone more experienced.

    What is it about studying climate science that gives one a priviledged position in judging whether tree rings make appropriate climate proxies?

    You answer your own question, one should study tree rings and should study proxies. Mathematics and statistics courses are much too general.

    What is it about studying climate science that gives one unique insite into whether ice cores make accurate temperature proxies?

    Again, you answer your own question, one should study ice cores and should study temperature. Probably under different instructors and professors with a lot of chemistry and physics thrown in. Look at some course curricula from a university that offers a degree. Mathematics and statistics courses are much too general.

    There is nothing “unique” about climate science. It is a mixture of many disciplines.

    Climate science is unique in that people need it to be a quantified, hard science Most of the disciplines in your mixture are more descriptive than quantitative. IMO you underestimate the difficulty of achieving such a quantitative mixture.

    cheers,
    John [just another technical guy trying to learn about Climate Science]

  180. Posted Jan 31, 2008 at 1:17 AM | Permalink | Reply

    The team is trying very hard to such standards to their own work now.

    By acknowledging errors and learning from them. mike even over-emphasizes that his PCA work was not wanting.

  181. Mark T
    Posted Jan 31, 2008 at 2:17 AM | Permalink | Reply

    I disagree. Statistical method or methods used in an established hard science should:

    1 – produce meaningful quantitative results

    2 – these quantified results should have quantifiable statistical confidence measures, e.g. sd, r2, skill, whatever.

    Um, you didn’t reply to his post. His intent was pretty clear that the methods the team use, particularly PCA, were incorrectly applied. Not only were they incorrectly applied, none of the assumptions that are normally used for application were met. Interestingly, Mann even makes note of a few of these in MBH98 without any resolution.

    If and when Climate Science becomes such an established hard science, I would expect these same standards to be met. The team is trying very hard to such standards to their own work now.

    At least you’re willing to admit the team isn’t participating in hard science. But no, they are not trying hard, if they were, we’d stop seeing the use of BCPs and Mann et. al. would admit their errors.

    Again I disagree. A key part of a climate scientist’s work is statistical in nature, and Mann’s PhD Thesis was heavily statistical.

    Mann’s the one that said “I’m not a statistician.” The errors in his PCA method are fundamental. Pick up a book on PCA and you can spot them quickly.

    His PCA work was not “wanting”, he had overlooked a pecularity of PCA that MM found and Wegman believed would have been discovered had Mann had more experience. Mann had just graduated and Wegman believed MBH should have been reviewed by someone more experienced.

    To hell it wasn’t “wanting.” He completely screwed the application, failed to meet any of the requirements and used bad data. Wanting is an understatement. It wasn’t a “peculiarity” either, and I’m not sure where you got that from.

    BTW, here we are 10 years later and Mann refuses to admit he was wrong. He’s still publishing papers using the same tree-rings and very similar methods, still incorrectly applied.

    You answer your own question, one should study tree rings and should study proxies.

    And one of these days, we hope, the team members will actually get out and take their own cores, like Steve M. and MrPete did. They needed lots of heavy equipment, as I understand it, to carry their Starbucks coffee up the mountain.

    Mathematics and statistics courses are much too general.

    The “science” of tree-rings is nothing more than extracting a signal embedded in noise. Standard signal processing techniques. You just don’t seem to understand this point.

    Mark

  182. Mark T
    Posted Jan 31, 2008 at 2:18 AM | Permalink | Reply

    That should read

    The “science” of using tree-rings as proxies

    Mark

  183. Geoff Sherrington
    Posted Jan 31, 2008 at 3:03 AM | Permalink | Reply

    Re # 158 ourphyl

    On reading IPCC section 2.3.3, we find ‘Was there a “Little Ice Age” and a “Medieval Warm Period”?’

    ourphyl says the science was properly done and reported, but unread by 99/100 people. I read it, especially re Southern hemisphere and tree ring data from Tasmania.

    IPCC -

    Dendroclimatic evidence from nearby Tasmania (Cook et al., 2000) shows no evidence of unusual coldness at these times.

    Writer’s abstract, later:

    B. M. BUCKLEY1, E. R. COOK2, M. J. PETERSON3 and M. BARBETTI4
    (1) IASOS, University of Tasmania, GPO Box 252-77, Hobart, TAS, Australia, 7001
    (2) Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades, N.Y., U.S.A, 10964
    (3) Department of Plant Sciences, University of Tasmania, GPO Box 252-55, Hobart, TAS, Australia, 7001
    (4) NWG Macintosh Centre for Quaternary Dating, University of Sydney, Madsen Bldg. F09, Sydney, NSW, Australia, 2006
    Abstract A network of seven Huon pine ring-width chronologies is constructed from sites ranging in elevation from 200 to 950 metres above sea level in western Tasmania. The chronologies are analysed individually and collectively to explore Huon pine’s response to climate as a function of elevation. Three chronologies from greater than 700 metres in elevation exhibit a strong, direct response to temperature for most growing season months (p

    I cannot bring myself to call this robust science when the validity of the temperature data depends on selecting the right tree in hindsight. There are at least 5 confounding factors admitted in the paper, with little information on how corrections can be applied to them in a meaningful way that can be extrapolated back 1000 years. The calibration period also uses suspect ground temperature data.

    The Bristle Cone Pine problem over again? With the Huon Pine being touted as the best Australia can produce?

    ourphyl, I suggest that you take a dose of your own medicine and read the papers behind the IPCC references plus later ones. Climatology science, in general, barely qualifies to be called a science. Some of us are hoping it will mature and cease being hopeful gobbledegook.

  184. MarkW
    Posted Jan 31, 2008 at 6:01 AM | Permalink | Reply

    That is definately not my opinion. I support testing and testing reports e.g. Customer Surveys, Consumer Reports, for a start. I support and use testing organizations (so called Product Test) for most of my work.

    You claim that you support testing, but then you complain that unless one is an expert, one is not allowed to have an opinion. Pray tell, how does one test, without forming an opinion. How does one create a testing report, if one does not know enough about the subject to have an opinion.

    Your double standard is showing through, in neon colors.

    I disagree. Statistical method or methods used in an established hard science should:
    1 – produce meaningful quantitative results
    2 – these quantified results should have quantifiable statistical confidence measures, e.g. sd, r2, skill, whatever.
    If and when Climate Science becomes such an established hard science, I would expect these same standards to be met. The team is trying very hard to such standards to their own work now.

    If don’t agree that there is controversy in this area, then you haven’t been paying attention.
    The entire Wegman report revolved around whether the statistical methods used to create the hockey stick were valid or not. Wegman, an expert in statistics, concluded that they were not.

    Again I disagree. A key part of a climate scientist’s work is statistical in nature, and Mann’s PhD Thesis was heavily statistical. His PCA work was not “wanting”, he had overlooked a pecularity of PCA that MM found and Wegman believed would have been discovered had Mann had more experience. Mann had just graduated and Wegman believed MBH should have been reviewed by someone more experienced.

    I have never seen this much spin outside a political press conference.

    First you disagree that Mann’s statistical work was wanting. Then you acknowledge that it was wanting. The flaw in Mann’s work was way more than just an overlooked pecularity.

    Finally, I note that you acknowledge that climate scientists are not experts in tree rings and other proxies. Yet you persist in your delusion that only climate scientists should be allowed to review science that involves such proxies.

    Are you a politician in real life?

  185. Steve McIntyre
    Posted Jan 31, 2008 at 8:30 AM | Permalink | Reply

    The issues with MBH98 are not “simply” the erroneous PCA method, although that it is a colorful and interesting error. The failed verification statistics (e.g. the often discussed verification r2 failure), the lack of robustness to presence/absence of bristlecone pines, ad hoc handling of series such as Gaspe, are fundamental problems that are separate from the incorrect PCA method.

    Aside from the problems themselves, the cover-up of the problems has been a long and lugubrious story. For example, MBH98 claimed statistical skill (including verification r2), but failed to report that verification r2 results were ~0. IPCC TAR repeated the untrue claim of “statistical skill”. Mann refused to provide results for the AD1400 step so that this claim could be tested; Nature and NSF supported this refusal. When we reported this failure, UCAR issued a press release saying that this (and other claims) were “unfounded” even though Ammann and Wahl knew or ought to have known that, at a minimum, our claim in respect to verification r2 was correct. As a reviewer of Ammann and Wahl, I asked them to include the verification r2 stat; they refused and I was terminated as a reviewer. I met personally with Ammann and urged him to include the adverse verification r2 results. He still refused. So I filed an academic misconduct complaint and, lo and behold, the verification r2 results were reported in the revised Ammann and Wahl. At the NAS panel hearings, Mann denied even calculating a verificaiton r2 statistic as that would be a “foolish and incorrect” thing to do.

    Yes, other recent studies have also got something like a “HS” without using PCA, by simple old-fashioned cherrypicking. But each of these other studies has its own defects. The NAS panel unconscionably did not even check these other studies as to whether they used bristlecones/foxtails; they just “winged it” to use North’s phrase – a procedure that seems all too characteristic in climate reconstructions.

  186. Ulises
    Posted Jan 31, 2008 at 9:05 AM | Permalink | Reply

    # 183 :

    Geoff, the abstract you quote is from Buckley et al 1997, not Cook et al 2000.

    But I can’t share your aversion towards that study (Buckley). Further down in their abstract they stress

    the importance of careful site selection for dendroclimatic research

    Nothing to argue about, I think. They base their selection on correlations with local temperatures and have the plausibility to their side that the more extreme stands (in terms of elevation) give the best temperature signal. What more could they do ?

  187. Steve McIntyre
    Posted Jan 31, 2008 at 11:09 AM | Permalink | Reply

    Buckley came to see me at AGU and was very cordial and complimentary about the contribution that I was making, saying that the need to attend to improving statistical rigor was long overdue.

  188. Sam Urbinto
    Posted Jan 31, 2008 at 6:45 PM | Permalink | Reply

    One of the Q/A sections from members of the Barton hearing with Dr. Wegman that I posted on the BB after I reformatted the blocky transcript and separated the Q from the A :)

    This might give you some insight to what’s in there. Distill it down to what’s really going on, as an interesting exercise.

  189. Geoff Sherrington
    Posted Jan 31, 2008 at 7:09 PM | Permalink | Reply

    Re # 186 Ulises

    You are quite correct on dates and I apologise. I carelessly took the Springer-link date appearing immediately above the title on the Web page. Then the whole abstract that I submitted was cut short, making the meaning even more difficult.

    That ready apology being given, I still cannot accept that one can do accurate science like this with the requirement that a number of diffuse preconditions have to be met. We do not know if the preconditions can be accepted back to year 1,000 ad or whatever. Leaps of faith are perhaps acceptable in some theory of risk taking, but not when the huge global consequences for remediation of elusive “anthropogenic global warming” are pitted against them.

    There is a further complication that some logs have been recovered from underwater. I do not know how it is established that the original locations of these logs, before being swept downstream, fitted the altitude etc requirements that put them “in the club”. But maybe that is a deficiency of mine.

    I also mentioned doubt about surface temperature records used for the calibration period. These have been discussed elesewhere on CA.

    You ask what more can be done. Answer: Discard methods with unacceptable doubt. Archive the records and do not use them in the real world.

    Heck, I’m not suggesting that these authors are bad guys. I’m suggesting that there comes a point when you declare that you’ve made a deal of progress, but that the residual difficulties cause limits on future data use. That’s what should happen in mature science. The IPCC should not have stated

    Dendroclimatic evidence from nearby Tasmania (Cook et al., 2000) shows no evidence of unusual coldness at these times

  190. ourphyl
    Posted Jan 31, 2008 at 9:41 PM | Permalink | Reply

    Geoff (#183)

    ourphyl, I suggest that you take a dose of your own medicine and read the papers behind the IPCC references plus later ones.

    I agree, only been at this about a year and paleoclimatology does cover the universe ;) Blogs have been helpful getting started but I’ve bought a subscription to science and have been trying to learn from original literature for the past six months or so. As a former physicist/engineer I find proxy reconstruction, climate cycles, NA oscillation and stuff like that very intriguing.

    I don’t trust the UN, too political for my taste, so with the exception of scientists like Sue Solomon and Ram Ramanathan, I stayed away from IPCC for anything technical. I started with the Wegman report’s references and their reference links; use my science subscription as a search engine and have some continuity and much more than I can handle. (Always eager for new links though 8>))

    I am into Thermohaline Circulation and abrupt climate change. I am currently studying Ming Yang’s 2006 UNC PhD thesis. Grad students are newbies also so I find a thesis, well referenced, easy to understand and detailed enough to for my learning style. Along with all of Rial’s clique at Chapel Hill, I find D&O cycles, the Dryas events, and potential non-linear effects (chaos??) fascinating. I just can’t learn enough about them…

    Thank you very much again for your time and your very courteous reply. Any (non-IPCC) links would be gratefully received – hint, hint.

    Climatology science, in general, barely qualifies to be called a science. Some of us are hoping it will mature and cease being hopeful gobbledegook.

    I believe you are going in the right direction and I hope you are successful in moving paleoclimatology in a quantifiable (hard) science direction.

    cheers,
    John [just another technical guy trying to learn about Climate Science]

  191. ourphyl
    Posted Feb 1, 2008 at 12:55 AM | Permalink | Reply

    steve (#185)

    Thanks for your comments and let me complement you not only for creating the best climate blog on the internet but also for managing it with a patience, fairness and skill that is certainly unique for climat change blogs. That sincerely said I would call your attention to the last paragraph on page 27 of Ed Wegman’s report.

    The work initiated by Mann and his colleagues is still in its infancy, and as such further study, the use of wider proxy networks and the development of more sophisticated climate models will all be necessary future steps in propagating this research. It is not expected or likely that after preliminary research, definitive conclusions can be made about the earth’s climate over the past millennium.

    Seems pretty clear to me, if there’s none to be had, there’s none to be had.

    Do you agree?

    cheers,
    John [just another technical guy trying to learn about Climate Science]

  192. ourphyl
    Posted Feb 1, 2008 at 5:05 AM | Permalink | Reply

    MarkT (#181)

    Couple of points:

    I am terribly unskilled in consistently divining motivations or intent. I very often confuse my own and I know I can’t divine someone else’s. This may very well disqualify me from posting climate science blogs because almost all the debates there are between champion diviners.
    I believe a scientist that makes an error should correct it. The earlier that correction can happen, the better. If the error makes it through the process and is published, the scientist should publish a correction.

    If you agree, I think we are not too far apart on Mann and his “statistics”

    At least you’re willing to admit the team isn’t participating in hard science.

    Absolutely!

    But no, they are not trying hard, if they were, we’d stop seeing the use of BCPs and Mann et. al. would admit their errors.

    I disagree, look at the dates

    MBH98/99, MM03. Mann corrections 05(?)

    Business as usual!

    *************************************

    Mark said:
    The errors in his PCA method are fundamental.

    John said:
    His PCA work was not “wanting”, he had overlooked a pecularity of PCA that MM found and Wegman believed would have been discovered had Mann had more experience. Mann had just graduated and Wegman believed MBH should have been reviewed by someone more experienced.

    Wegman Committee said (page 4):

    In general, we found MBH98 and MBH99 to be somewhat obscure and incomplete and the criticisms of MM03/05a/05b to be valid and compelling. We also comment that they were attempting to draw attention to the discrepancies in MBH98 and MBH99, and not to do paleoclimatic temperature reconstruction. Normally, one would try to select a calibration dataset that is representative of the entire dataset. The 1902-1995 data is not fully appropriate for calibration and leads to a misuse in principal component analysis. However, the reasons for setting 1902-1995 as the calibration point presented in the narrative of MBH98 sounds reasonable, and the error may be easily overlooked by someone not trained in statistical methodology. We note that there is no evidence that Dr. Mann or any of the other authors in paleoclimatology studies have had significant interactions with mainstream statisticians.

    *************************************

    When you say:

    “To hell it wasn’t “wanting.” He completely screwed the application, failed to meet any of the requirements and used bad data. Wanting is an understatement. It wasn’t a “peculiarity” either, and I’m not sure where you got that from.”

    You’ll have to take it up with the Wegman Committee, that was their finding.

    Personally, I believe that we will make better progress

    with the climate scientists doing ice cores, e.g.

    The analyses of two ice cores from a southern tropical ice cap provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent. Annual variations in visible dust layers, oxygen isotopes, microparticle concentrations, conductivity, and identification of the historical (A.D. 1600) Huaynaputina ash permit accurate dating and time-scale verification. The fact that the Little Ice Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.

    and the professional statisticians doing:

    …Over the course of four assessment reports, a small number of statisticians have served as authors or reviewers. Although this involvement is encouraging, it does not represent the full range of statistical expertise available. ASA recommends that more statisticians should become part of the IPCC process. Such participation would be mutually beneficial to the assessment of climate change and its impacts and also to the statistical community.

    as Ed Wegman is currently trying to get them to do ;)

    cheers,
    John [just another technical guy trying to learn about Climate Science]

  193. Posted Feb 1, 2008 at 8:22 AM | Permalink | Reply

    sod, perhaps you should look at the Loehle paper before making such ridiculous claims.

    Loehle anomaly 1000 AD approximately +0.35 C

    Today’s instrumental record:
    UAH +0.11
    GISS +0.39
    RSS +0.08
    HadCRUT3 +0.21
    NCDC +0.40

    How is it again that you get from Loehle that we are living in the hottest period in 1000 years?

    you do understand, that “anomalies” can t be compared like that?

    you need a COMMON base, don t you?

    sod pretty much thinks that if he makes the same dubious claim, over and over again, and believes it fervently enough, he will have made a convincing argument for the next guy. Rhetorical arguments are not going to settle the science, they count as a thinking certainly, but the goal is not understanding, it is conversion. Rhetorical arguments belong in the province of religion. Think about that sod.

    my argument is convincing, because it is simple and true:
    Loehle and the Mann hockey stick look at DIFFERENT time intervals.
    the Loehle results for the “Mann period” do NOT include a significant “MWP”. fact.

  194. Ron Cram
    Posted Feb 1, 2008 at 8:56 AM | Permalink | Reply

    sod,

    What do you mean “Mann period” and how you calculating that? You say Loehle and Mann look at different time intervals, but I believe they both look back 2000 years. It seems to me you should be looking at the “MWP period” where Loehle clearly shows a strong WMP and Mann does not. Your point is quite obscure.

  195. Posted Feb 1, 2008 at 9:11 AM | Permalink | Reply

    sod,

    What do you mean “Mann period” and how you calculating that? You say Loehle and Mann look at different time intervals, but I believe they both look back 2000 years. It seems to me you should be looking at the “MWP period” where Loehle clearly shows a strong WMP and Mann does not. Your point is quite obscure.

    i don t think so. the “original” hockey stick is a “1000 years” reconstruction.

    a google image search will provide quite a lot of pictures to you.

    there is a Mann 2000 years reconstruction (showing a small bump before 1000, btw) and an overview can be found here.

    but most people wouldn t refer to it when talking about “the” hockeystick..

  196. Steve McIntyre
    Posted Feb 1, 2008 at 9:17 AM | Permalink | Reply

    #191. You observe that Wegman said:

    “It is not expected or likely that after preliminary research, definitive conclusions can be made about the earth’s climate over the past millennium.

    and add

    Seems pretty clear to me, if there’s none to be had, there’s none to be had.

    Do I agree with us? Our conclusion on MBH was that – with his data and methods, he could not assert that the 20th century climate was unprecedented in the millennium. We didn’t say that we had proved that the MWP was warmer.

    I have a similar attitude to other Team studies purporting to show that the modern warm period is warmer than the MWP – I don’t think that they’ve proved this using their data and methods, each study having slightly different problems, but the high degree of linkage between Team studies in terms of proxy selection means that a couple of problem proxies (e.g. bristlecones) can affect a lot of studies that are advertised as “independent”. I’ve resisted the temptation to offer up a Loehle-type reconstruction other than to show the non-robustness of Team reconstructions to slight and trivial variations of proxy selection.

    A couple of bright young scientists at the 2006 AGU told me (on condition that they not be identified) that they thought that I had pretty much killed the Hockey Team-style reconstructions and that the only cure was new high-quality data – which might take 10-20 years to collect and digest.

    I think that it should be possible to get better data. The seeming difficulty in arriving at a solid millennial history is itself curious – the foraminiferal Mg-Ca data from the Pacific Warm Pool has a high degree of coherence with the Vostok dO18 data. So why do we seemingly have so much trouble with near-time millennium results?

  197. ourphyl
    Posted Feb 1, 2008 at 10:51 AM | Permalink | Reply

    Steve (#196)

    Thanks Steve, I agree with you and your bright young scientists.

    WRT schedules, I don’t want to be a wet blanket but, in my experience, it’s rare that two people agree exactly on where and/or when something past happened – even if it happened only yesterday. Six or eight groups of homo sapiens and a couple of thousand years are too much even for my imagination.

    Nevertheless, here’s to new data, and new analysis — soon

    cheers,
    John [just another technical guy trying to learn about Climate Science]

  198. Mark T.
    Posted Feb 1, 2008 at 11:07 AM | Permalink | Reply

    I disagree, look at the dates

    MBH98/99, MM03. Mann corrections 05(?)

    Business as usual!

    Um, no, they released another paper this past summer (linked on the left sidebar) as well as the Amman paper in 2006 (in which they finally reported their dismal r2 numbers, though that paper may still be “in press”). I AM looking at the dates. Mann was actually rather disgusted with the IPCC for downplaying the recons, too, which was only released last May. The IPCC matter, while not specifically a topic of this thread, is a different ball of wax, btw, simply because the NAS and Wegman stuff had not been concluded before the cutoff date (as I recall, in any case, neither is discussed in the IPCC report). The bottom line: Mann refuses to admit to his problems, and we’re (Steve) still being forced to review paper after paper that use BCPs and commit the same tired errors.

    You’ll have to take it up with the Wegman Committee, that was their finding.

    I’m not sure what you’re getting at here. Wegman said the Mann studies were wanting, I agreed and you disagreed. There’s very little in the PCA methodology used by Mann (which has not been solved with RegEM, btw) that is viable, so “wanting,” as I concluded, is an understatement. Personally, I think Wegman was being nice.

    Mark

  199. Mark T.
    Posted Feb 1, 2008 at 11:09 AM | Permalink | Reply

    i don t think so. the “original” hockey stick is a “1000 years” reconstruction.

    So the Loehle recon covers Mann’s recon PLUS… you make no real point here.

    Mark

  200. Mark T.
    Posted Feb 1, 2008 at 11:24 AM | Permalink | Reply

    Thanks Steve, I agree with you and your bright young scientists.

    I think this is called progress… Primarily w.r.t. the “hockey stick” since that’s the point about “Mann’s conclusions” that are specifically targeted in this thread and the North/Wegman reports. I.e. saying the stick is unsupportable does not a) make any claims towards a contrary recon (such as the Loehle recon may show) or b) any claims about the broader “AGW” claims that Mann regularly makes (along with many others, of course). It simply means that the recons are unsupported by the evidence provided, which leaves claims about unprecedented warming in 20th century unfounded (it may be, we just can’t conclude as such from the recons).

    Mark

  201. Peter Thompson
    Posted Feb 1, 2008 at 12:05 PM | Permalink | Reply

    sod #193,

    you do understand, that “anomalies” can t be compared like that?

    you need a COMMON base, don t you?

    Yes I understand it, and yes you do. When one eyeballs the HadCRUT3 and Loehle’s reconstruction one sees that they zero themselves at a similar time frame, although it is difficult to nail it down with the difference in resolution. It is enough given the scale of the y-axis to make them comparable however, so we are back to tenths of a degree. Is that really sufficient to make the claim?

  202. Posted Feb 1, 2008 at 3:40 PM | Permalink | Reply

    So the Loehle recon covers Mann’s recon PLUS… you make no real point here.

    Mark

    you can spin it as much as you want.

    since 1000 ad neither Loehle nor the Mann hockey stick show a MWP. fact.

    Yes I understand it, and yes you do. When one eyeballs the HadCRUT3 and Loehle’s reconstruction one sees that they zero themselves at a similar time frame, although it is difficult to nail it down with the difference in resolution. It is enough given the scale of the y-axis to make them comparable however, so we are back to tenths of a degree. Is that really sufficient to make the claim?

    people repeat the claim that Loehle contradicts/destroys the hockey stick. that is simply nonsense.
    if you haven t noticed it so far: climate change ALWAYS is about tenths of a degree….

  203. Sam Urbinto
    Posted Feb 1, 2008 at 4:12 PM | Permalink | Reply

    Explain statistically what happened in 1977 with the anomalies.

    “The Temperature”, my left eyeball.

  204. Peter Thompson
    Posted Feb 1, 2008 at 5:24 PM | Permalink | Reply

    sod #202:

    people repeat the claim that Loehle contradicts/destroys the hockey stick. that is simply nonsense.
    if you haven t noticed it so far: climate change ALWAYS is about tenths of a degree….

    Allow me to paraphrase: It’s 0.1 C hotter! We’re all gonna die! Good luck getting that which you seek with that message.

  205. ourphyl
    Posted Feb 2, 2008 at 12:02 AM | Permalink | Reply

    (#200)

    Mark said:

    ourphyl said: Thanks Steve, I agree with you and your bright young scientists.

    I think this is called progress… Thanks Mark, I agree we are making progress.

    Primarily w.r.t. the “hockey stick” since that’s the point about “Mann’s conclusions” that are specifically targeted in this thread and the North/Wegman reports. I.e. saying the stick is unsupportable does not a) make any claims towards a contrary recon (such as the Loehle recon may show) or b) any claims about the broader “AGW” claims that Mann regularly makes (along with many others, of course). It simply means that the recons are unsupported by the evidence provided, which leaves claims about unprecedented warming in 20th century unfounded (it may be, we just can’t conclude as such from the recons).

    Mark

    I agree there are many such posts here but AFAIAC they are probably off-topic and not at all what the Wegman/North reports “say”.

    The Wegman report has four recommended actions on page six extracted from Section 7 conclusions and recommendations on pages 51/52

    W1- A more intense level of scrutiny of academic work that affects public policy, e.g. more broadly based IPPC “Peer Reviews”

    W2- Comprehensive disclosure and ownership policy for all federally funded research.

    W3- Mandatory funded statistical evaluation phase by staticians for all federal grant applications related to major policy decisions…

    W4- Emphasis on Federal funding for research on fundamental mechanisms of climate change.

    To me W3 says that Wegman Committee doesn’t care what statistical analysis tool or tools Mike Mann does or doesn’t use as long as an ASA statistician analyzes the results before release.

    The North report is an entirely different sort of animal, there are no recommendations. There are interesting discussions in a 15 page chapter 9 Statisical Background and in a 5 page chapter 11 Large Scale Multiproxy Reconstruction Techniques

    Finally we have:

    OVERALL FINDINGS AND CONCLUSIONS

    Based on its deliberations and the materials presented in Chapters 1–11 and elsewhere, the committee draws the following overall conclusions regarding large-scale surface temperature reconstructions for the last 2,000 years:

    The instrumentally measured warming of about 0.6°C during the 20th century is also reflected in borehole temperature measurements, the retreat of glaciers, and other observational evidence, and can be simulated with climate models.
    Large-scale surface temperature reconstructions yield a generally consistent picture of temperature trends during the preceding millennium, including relatively warm conditions centered around A.D. 1000 (identified by some as the “Medieval Warm Period”) and a relatively cold period (or “Little Ice Age”) centered around 1700. The existence of a Little Ice Age from roughly 1500 to 1850 is supported by a wide variety of evidence including ice cores, tree rings, borehole temperatures, glacier length records, and historical documents. Evidence for regional warmth during medieval times can be found in a diverse but more limited set of records including ice cores, tree rings, marine sediments, and historical sources from Europe and Asia, but the exact timing and duration of warm periods may have varied from region to region, and the magnitude and geographic extent of the warmth are uncertain.

    It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.

    Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified.

    Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.

    So there we are. By choosing not to make recommendations, North’s committee allows what we used to call an “all things to all men” approach. For example, on page 114:

    The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes the additional large-scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005b, Rutherford et al. 2005, D’Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press) and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press).

    Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium. The substantial uncertainties currently present in the quantitative assessment of large-scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales. However, the methods in use are evolving and are expected to improve.

    This might suggest a more robust answer to CA questions as to why Mike Mann continues to plunge ahead. That’s what “everyone” wants. The United States is a democracy with a bicameral legislature and separation of powers. Unlike Canada, we wash our dirty laundry and then decide what to do.

    Please don’t kill the messenger, remember that I am still trying to learn :(

  206. Steve McIntyre
    Posted Feb 2, 2008 at 12:54 AM | Permalink | Reply

    I did a number of posts when these reports came out. There’s an interesting audio of North giving a seminar on this in which he says that the panel didn’t “do any research”, that they “just winged it”, saying that’s what these panels do. North’s a decent guy, but the disconnect between the casualness of academic climate science due diligence and the total lack of understanding of due diligence in other walks of life is sometimes simply breathtaking.

  207. Posted Feb 2, 2008 at 4:10 AM | Permalink | Reply

    Allow me to paraphrase: It’s 0.1 C hotter! We’re all gonna die! Good luck getting that which you seek with that message.

    0.1°C, if you stake everything in your favor. and growing.

  208. DavidH
    Posted Feb 2, 2008 at 5:00 AM | Permalink | Reply

    Pocket Oxford Dictionary:

    plausible
    (Of argument, statement, etc.) specious,seeming reasonable or probable;(of person) persuasive but deceptive;

    This is the “all things to all people” bit of the report, which I think speaks volumes. I find it hard to think anyone on the panel was unaware of the ambiguity of the word. They could not, and did not, find any fault with the criticism of McIntyre and McKitrick but did make many criticisms of Mann. They also made the very damning “murky” statement in respect of reconstructions generally prior to 1600 AD. They simply could not bring themselves, after the many statements they had made individually prior to their study, in support of Mann and their beliefs about current warming, to say that his paradigm changing study so fundamental to the IPCC, 2001 conclusions was simply WRONG.

  209. ourphyl
    Posted Feb 2, 2008 at 3:08 PM | Permalink | Reply

    (*206)

    What’s even more breathaking to me is the attempt to base public policy on “science”. Science should be dynamic and driven by skepticism. Policy should be static and driven by consensus.

    I believe due diligence is plausable for Buffet but is implausable for Bernanke.

    I believe climate measures e.g. temperatures, like market measures, e.g. prices are chaotic. Their behavior is non-linear and their analysis requires something like fractals ;)

  210. ourphyl
    Posted Feb 2, 2008 at 3:23 PM | Permalink | Reply

    (#207)

    You are right. We all are going to die. The only uncertainty is when ;)

    john [just a techie trying to learn]

  211. ourphyl
    Posted Feb 2, 2008 at 3:29 PM | Permalink | Reply

    (#208)

    Right on. “plausible” is much better, short and sweet. Helps keep us open-minded folk pleasant and smiling (at least until our brains fall out) ;)

    john [just a techie trying to learn]

  212. Paulchina
    Posted Feb 7, 2009 at 2:46 PM | Permalink | Reply

    There’s been some discussion here of what wikipedia has to record on all this. Their edit has changed since earlier in this thread but the comment that stands out right NOW is:

    leading to even more confusion on the situation.

    You can’t beat settled science. If this blog has contributed anything it is to put science back where it should be for a chaotic system. Well done and KUTGW (= keep up the good work or Keep Under-mining Theories of Global Warming)

  213. Jonathan Bagley
    Posted Feb 10, 2009 at 10:57 AM | Permalink | Reply

    This was very helpful to me, a relatve newcomer to the GW debate. As I have a probability and statistics background I was particularly interested in Wegman’s views. I don’t want to come to the chilling conclusion that the world is being ruled by a dozen madmen and their acolytes, but it’s beginning to look that way. I’m almost tempted to give up smoking so I live to see the denouement.

  214. nevket240
    Posted Oct 26, 2009 at 6:03 AM | Permalink | Reply

    http://www.telegraph.co.uk/news/6425269/The-real-climate-change-catastrophe.html

    Nearly everyone gets a mention.
    regards

  215. SAM (Please use this as I am Stephen A. McIntyre, unaffiliated with and unknown to the author/blogger of this site
    Posted Nov 28, 2009 at 2:59 PM | Permalink | Reply

    First-timer here. This is thrilling and healthy discourse. I feel like I’ve been extricated from the morass of politicized media hype. Thanks, Folks and patience, please.

    Reminds me of early discussions on evolution theory. Dedicated souls make contributions, and so, reputations. Egos intrude, refuters and defenders roar and in the end, scientific understanding is advanced.

    I have faith that new research will clarify and refine current understanding (if budget cuts don’t kill us all). Might I make a call for humility to those whose work has come under scrutiny? An ego set gently on the shelf for a time allows for gratitude in the face of criticism and affords opportunities to improve one’s own work.

    The hockey stick, broken or not, has led to this flurry of inquiry. Keep it coming!

  216. Kevin O'Neill
    Posted Dec 4, 2011 at 2:27 PM | Permalink | Reply

    Hasn’t Wegman at this point been totally discredited? I would think that an update is appropriate to prevent readers from being misled into thinking Wegman’s an impartial, reliable, and/or expert source.

  217. Posted Jan 31, 2013 at 7:51 AM | Permalink | Reply

    Reblogged this on Climate Ponderings.

13 Trackbacks

  1. [...] “Hanno” is just another variation of Mann’s discredited Hockey Stick based on questionable mathematics, outright errors such as data inversions, and dubious or excluded proxies that may not reflect [...]

  2. [...] this graph from “Hanno” is just another variation of Mann’s discredited Hockey Stick based on questionable mathematics, outright errors such as data inversions, and dubious or excluded proxies that may not reflect [...]

  3. [...] study raised, and it was also emphasised in the Wegman report on the Hockey Stick, and in other independent studies of the Hockey Stick controversy. Of course it is also an ongoing issue in Steve McIntyre’s campaign to get hold of data and [...]

  4. [...] study raised, and it was also emphasised in the Wegman report on the Hockey Stick, and in other independent studies of the Hockey Stick controversy. Of course it is also an ongoing issue in Steve McIntyre’s campaign to get hold of data and [...]

  5. [...] side of the 'hockey stick' kerfuffle. Those who appreciate looking at both sides might enjoy this: The Wegman and North Reports for Newbies Climate Audit From the Wegman panel report: …Where we have commonality, I believe our report and the [NAS] [...]

  6. [...] The Wegman and North reports were commissioned by the US government because the now very public debate was concerning US [...]

  7. [...] were finally forced to reveal your methods, your novel result could be seen to came from a stupid mathematical error combined with using bristlecone pines, known to be an invalid temperature proxy. That made your [...]

  8. By Copygate « Climate Audit on Oct 12, 2010 at 4:41 PM

    [...] As readers know, Raymond Bradley’s allegation that “text was just lifted verbatim from my book and placed in the Wegman Report” has been widely publicized following Bradley’s interview with USA today. The allegation pertains to Wegman’s boilerplate section (2.1) describing proxies, a section in which neither MBH98-99 nor MM2003, 2005abcd are mentioned, and on which no Wegman conclusions depend. Nor does it affect the under oath endorsement of Wegman conclusions given at the House Committee hearings by Gerald North and Peter Bloomfield – see here. [...]

  9. [...] North I can kinda understand, because he chaired an earlier (and also widely criticized) enquiry into Dr. Mann’s hijinks. So he was a friend of Manns, and he’d covered up for Mann [...]

  10. [...] De la estadística ni hablemos, que ya sabemos desde el informe Wegman que una de las características de la ciencia del calentamiento global es que se trata de un pequeño grupo muy cerrado de autores que no utilizan ni aprenden de los especialistas en estadística. Vamos, que van a su aire. It is important to note the isolation of the paleoclimate community; even though they rely heavily on statistical methods they do not seem to be interacting with the statistical community. [-->] [...]

  11. [...] For more on the hockey stick shenanigans, for the more forensically inclined, see the Wegman and North Reports for Newbies. [...]

  12. [...] Edward Wegman after he produced a report through George Mason University that criticized the methodology in Mann's hockey stick chart. Alarmists have accused Wegman of plagiarism in their efforts to prop [...]

  13. [...] all these points, and persisted in claiming that his analysis was valid. Eventually there were two official public inquiries in the U.S. – one consisting of scientists and one of statisticians. The scientist one concluded [...]

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