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 https://climateaudit.org/wp-content/uploads/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
Climate Audit 
217 Comments
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.
This was very much needed, and makes the entire issue so much clearer.
Yup. It’s called caught between the devil and the deep blue sea.
It’s called “fake but accurate”. Tried and true in the media business.
What a great summary! I wonder how the spin doctors will react.
FWIW, in this wikipedia entry:
http://en.wikipedia.org/wiki/Ross_McKitrick#Criticism_of_Mann_et_al
There’s a contested statement:
Anyone with any wikipedia pull may want to see about getting that cleaned up.
From your article, “it doesnt mean Dr. Manns conclusions are wrong”
You never really addressed the conclusion of the work, nor the Mann 2003 paper.
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!!
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.
ks
You have missed the point of Wegman’s word equation.
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.
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.
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.”
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.
ks, this is from the Wegman Report:
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.
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
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.
#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.
Re #16:
I forgot to add “in the USA lower 48” when discussing GISTEMP. I will await the inevitable flames.
#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.
17, at the risk of being OT, that link says right up front:
Correct me if I’m wrong, but isn’t that one of Gore’s stock sayings?
>> 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).
John V., re: #22.
The science is far from settled, but that should settle you a bit.
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.
22,
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.
#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.
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.
Where is Boris when things really get interesting.
Wegman wrote:
The best statician of the US cannot reproduce MBH.
When I went to go copy it, I saw John Quiggin has updated the update.
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.
#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?).
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
#30 Sam Urbinto
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?
“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.
Re Richard Smith at the ASA. Who says plausible has odds of 2 to 1? Its evens at best
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
From The NAS (North) Report
From the Richard Smith ASA newsletter
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.”
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.
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???
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.
Subsequent to the Wegman Report – in response to the House Committee – Mann archived part of his code. But it doesnt 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?
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.
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.
#41. Jimmy, take a look at the post here . Bump the post if you want to discuss.
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.
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.
#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.
#45 Tim
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”.
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.
Same thing that prevents him doing a tarot card reading ?
#45 Tim Ball says
But Steve says #18
Which is it?
#16
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:
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
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.
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.
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.
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.
#49
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.
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?
RE 28 where is boris when things get interesting?
He’s enacting his name.
RE 41. Have a look Jimmy. The more brains the merrier.
RE 31. I’m here. Is this stuff in his nature archive or some other place.
Toss me a pointer.
Sandy Szwarc explains here, why the hockeystick will linger on and on.
Mythbusting is though.
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, DArrigo 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.
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:
All but one (Wilson et al) exceed this best after date.
Jeff
#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.
#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:
Read the rest here.
“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”
“Youve got to understand that the Warmers have Billions of Dollars, and their reputations on the line here. They arent 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, DArrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann (2006/2007 ?)
#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?
#66 ks, In particular look at the heading “Spurious” where SteveM runs the rule over a lot of studies and their spurious correlation. Link
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.
“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.
#70 Acleron. Meet #65
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.
# 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.
[video src="http://www.met.tamu.edu/people/faculty/dessler/NorthH264.mp4" /]
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
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
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:
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,
DArrigo 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.
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
#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
#73 ks: You are being facetious, aren’t you, when you say, “From Norths 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 didnt 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
#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 dont 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.
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
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
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
#73 ks.Yes it was von Storch et al summary of what the NAS report said.
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.
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.
kc
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.
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.
#17 John A –
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.
I would propose that in this era of Political Correctness, we should demand to be called…
AGW Skeptics
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.
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.
Steve McIntyre:
I agree with Ross. It’s worth another paper.
ks,
If you are unaware of the controversy surrounding the bristlecone proxies, then you have not studied this issue enough to form an opinion.
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!
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.
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.
See above.
I think this would be called the icing on the cake of reasons why not to use BCPs in particular.
Mark
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
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.
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
Re #98,
Thanks David Holland. The paper is exactly what is needed. [snip]
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.
#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.
re: #96
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.
Oh, cool, I hadn’t noticed that before. Not very “conspicuous.” 🙂
Mark
David Holland
Please e-mail me at pmaynard@pmaynard.plus.com
Thanks
Paul
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.
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.
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…..
#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.
Re #106: WTF? There is another term that should be explained in the glossary 🙂
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.
Re#109:
It is Whiskey, Tango, Foxtrot.
Roger that, Trevor?
BCH?
Bose, Chaudhuri and Hocquenghem?
Mark
#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.
What The Fudge,
used by confectioners when their chocolate treats go awry.
Re # 105 T J Olson
“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.
–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.
MarkR:
According to Wiki:
This is rich.
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.
#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.
I only have a reason to give my thanks to Wikipedia. Their article on Astrobiology includes a link to my conference on Astrobiology.
Used that one just the other day! (literally: mammatus up – to indicate a ‘module’ which had ‘died’)
e*t s*** and bark at [the] moon?
The following quote caught my eye:
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.
My quote above was from Richard Smiths account of the 2006 American Statistical Association session here.
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?
Correction:
2) Wahl and Ammann (2006) … unpublished (initially accepted, then rejected, and now withdrawn)
Is this correct?
RE 122.
You got them both.
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
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
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.
No.
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:
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.
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?
Alex Harvey (#129) writes,
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.
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.”
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
Alex Harvey says:
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.
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!
#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.
eric mcfarland says:
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
Thanks Raven. As for the MWP … does anybody actually know how warm it was or how widespread?
I’ve got a song for Raven:
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?
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?
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?
Alex Harvey (#144):
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
Part of the problem with the IPCC, is that they used the hockey stick, and that particular section was written by Mann himself.
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?
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.
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”
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.
==================================
uh, divergence.
=========
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
#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.
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.
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.”
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:
Or as Dr. North put it:
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.
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.’
i am very glad, that the Loehle paper settled this issue:
we are living in the hottest period over the last 1000 years..
MarkW (#147)
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”).
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)
yup
yup. (I always say that it takes one to know one. Most probably then, your conclusion about my arrogance is a correct one.)
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
ourphyl says:
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?
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.
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.
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
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.
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,
“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:
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.
Steve M. did not create the inquisition, and the fact that Mann continues to defend the indefensible is his fault, not Steve’s.
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.
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.
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.
Nonsense, the team keeps publishing papers, and Steve keeps auditing.
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.
Sure enough…
Mark
J. Peden (#154)
Thanks for your thoughtful response.
Well at least we agree about that much.
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.
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
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.
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.
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 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
and recognition of the difficulties
Thanks again Sam, you’re very helpful.
cheers,
j
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
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?
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/ ?
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.
sod,
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.
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.
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?
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.
J.Pedin (#168)
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:
We could agree if you are willing to replace the stricken phrase by a long ways to go to become an
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.
MarkW (#175)
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.
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.
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.
You answer your own question, one should study tree rings and should study proxies. Mathematics and statistics courses are much too general.
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.
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.
By acknowledging errors and learning from them. mike even over-emphasizes that his PCA work was not wanting.
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.
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.
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.
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.
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.
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
That should read
Mark
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 –
Writer’s abstract, later:
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.
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.
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?
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.
# 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
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 ?
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.
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.
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
Geoff (#183)
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.
I believe you are going in the right direction and I hope you are successful in moving paleoclimatology in a quantifiable (hard) science direction.
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.
Seems pretty clear to me, if there’s none to be had, there’s none to be had.
Do you agree?
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”
Absolutely!
I disagree, look at the dates
Business as usual!
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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.
and the professional statisticians doing:
as Ed Wegman is currently trying to get them to do 😉
you do understand, that “anomalies” can t be compared like that?
you need a COMMON base, don t you?
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.
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..
#191. You observe that Wegman said:
and add
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?
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
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.
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
So the Loehle recon covers Mann’s recon PLUS… you make no real point here.
Mark
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
sod #193,
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?
you can spin it as much as you want.
since 1000 ad neither Loehle nor the Mann hockey stick show a MWP. fact.
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….
Explain statistically what happened in 1977 with the anomalies.
“The Temperature”, my left eyeball.
sod #202:
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.
(#200)
I think this is called progress… Thanks Mark, I agree we are making progress.
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”.
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.
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:
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 😦
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.
0.1°C, if you stake everything in your favor. and growing.
Pocket Oxford Dictionary:
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.
(*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 😉
(#207)
You are right. We all are going to die. The only uncertainty is when 😉
john [just a techie trying to learn]
(#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]
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:
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)
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.
http://www.telegraph.co.uk/news/6425269/The-real-climate-change-catastrophe.html
Nearly everyone gets a mention.
regards
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!
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.
Reblogged this on Climate Ponderings.
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