Flashback: Wegman report ( Warnings about Skulduggery about Climate Change Scientists)

"In our further exploration of the social network of authorships in temperature reconstruction, we found that at least 43 authors have direct ties to Dr. Mann by virtue of coauthored papers with him. 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. Moreover, the work has been sufficiently politicized that this community can hardly reassess their public positions without losing credibility. ...

The block (cluster) structure is very clear. Michael Mann is a co-author with every one of the other 42. The black squares on the diagonal indicate that the investigators work closely within their group, but not so extensively outside of their group. ... However, it is immediately clear that the Mann, Rutherford, Jones, Osborn, Briffa, Bradley and Hughes form a clique, each interacting with all of the others. A clique is a fully connected subgraph, meaning everyone in the clique interacts with every one else in the clique. ...

The cliques are very clear in this layout. In addition to the Mann-Rutherford-Jones-Osborn-Briffa-Bradley-Hughes clique there are several others that are readily apparent. They are Rind-Shindell-Schmidt-Miller, Cook-D’Arrigo-Jacoby-Wilson, Folland-Vellinga-Allan-Knight, Stahle-Shugart-Therrell-Druckenbrod-Cleveland, Sangoyomi-Moon-Lall-Abarbanel, and Clement-Zebiak-Cane. The last cluster is somewhat of the miscellaneous cluster of people who had published with Michael Mann,

The Wegman report

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Category: climate science
Posted on: July 14, 2006 12:30 PM, by William M. Connolley

There is apparently a strange thing called the Wegman report. Sadly that link only contains Smokey Joe Bartons comments on selected extracts (does anyone know where the full thing is? Is it published? Also quite what the committee/panel is, is rather vague. [Update! Aha... I should have known: since it was Per who commented on it, and since it reads like it was written by M&M, the dark side pointed me towrds the full thing]). Still, what did they say? (BTW, in case you hadn't realised, this is yet more HS stuff :-)

the paleoclimate reconstruction... does not provide insight and understanding of the physical mechanisms of climate
change... What is needed is deeper understanding of the physical mechanisms of climate change Yup, nothing like stating the bleedin' obvious. Anything better in there?

evaluation by statisticians should be standard practice. This evaluation phase should be a mandatory part of all grant applications and funded accordingly. Aha! He wants more money and more work for statisticians. Not a particularly odd thing for him to say, but I don't see hard-pressed cliamte researchers wanting to give up their grant money. Unless there is extra available, perhaps from cancelling the "war on terror".

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." Sounds good, but probably naive expressed like that. Who else, apart from people who write climate papers, can assess and synthesise the science?

As statisticians, we were struck by the isolation of communities such as the paleoclimate community that rely heavily on statistical methods, yet do not seem to be interacting with the mainstream statistical community. The public policy implications of this debate are financially staggering and yet apparently no independent statistical expertise was sought or used." Dubious. It gets said again and again that the HS isn't a major part of attribution, but no-one listens. Probably a good argument for not letting people who know nowt about climate too close to it. I'm not sure about the isolated bit... maybe it just means Wegman doesn't know Mann. But then Mann doesn't know Wegman... does that make W isolated?

As mentioned earlier in our background section, tree ring proxies are typically calibrated to remove low frequency variations. The cycle of Medieval Warm Period and Little Ice Age that was widely recognized in 1990 has disappeared from the MBH98/99 analyses, thus making possible the hottest decade/hottest year claim. However, the methodology of MBH98/99 suppresses this low frequency information. This is weird, and appears to mix up different things. I haven't seen anyone previously claim that the MBH method suppresses low-f info thats in the proxies. If tree rings don't have the info, it can't create it. The assertion about what was widely recognised in 1990 is dubious, and appears to be a re-run of the IPCC '90 fig 7.1 stuff again (see http://en.wikipedia.org/wiki/MWP_and_LIA_in_IPCC_reports).

Um... so, that was fun, but the full report would be more interesting.

OK, picking a bit from that:

[M&M 2003] ... claimed that using the MBH98 methodology and the Northern Hemisphere average temperature index for the period 1400-1980 shows that temperatures in the 15th century exceeded those of the late 20th century. In particular, they claim that MBH98's incorrect usage of PCA alone resulted in the well-known "hockey stick" shape. This is a bit weird. If using MBH98 produces a warm 15th C, how can they also claim it always produces a HS?

And by Steve McIntyre
at Climate Audit:

The Wegman and North Reports for Newbies

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November 6th, 2007

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:

From the Preface of the NAS Reort...see link just above:

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This committee was asked to describe and assess the state of scientific efforts to reconstruct surface temperature records for the Earth over approximately the last 2,000 years. (The full Statement of Task appears in Appendix A.)

Normally, a technical issue such as surface temperature reconstructions might not generate widespread attention, but this case brings interesting lessons about how science works and how science, especially climate science, is communicated to policy makers and the public.

The debate began in 1998 when a paper by Michael Mann, Raymond Bradley, and Malcolm Hughes was published in the journal Nature.

The authors used a new methodology to combine data from a number of sources to estimate temperatures in the Northern Hemisphere for the last six centuries and later for the last 1,000 years.

This research received wide attention, in part because it was illustrated with a simple graphic, the so-called hockey stick curve, that many interpreted as definitive evidence of anthropogenic causes of recent climate change.

The research was given prominence in the 2001 report of the Intergovernmental Panel on Climate Change and then was picked up by many in the wider science community and by the popular media.

Science is a process of exploration of ideas—hypotheses are proposed and research is conducted to investigate.

Other scientists work on the issue, producing supporting or negating evidence, and each hypothesis either survives for another round, evolves into other ideas, or is proven false and rejected.

In the case of the hockey stick, the scientific process has proceeded for the last few years with many researchers testing and debating the results.

Critics of the original papers have argued that the statistical methods were flawed, that the choice of data was biased, and that the data and procedures used were not shared so others could verify the work.

This report is an opportunity to examine the strengths and limitations of surface temperature reconstructions and the role that they play in improving our understanding of climate.

The reconstruction produced by Dr. Mann and his colleagues was just one step in a long process of research, and it is not (as sometimes presented) a clinching argument for anthropogenic global warming, but rather one of many independent lines of research on global climate change.

Using multiple types of proxy data to infer temperature time series over large geographic regions is a relatively new area of scientific research, although it builds upon the considerable progress that has been made in deducing past temperature variations at single sites and local regions.

Surface temperature reconstructions often combine data from a number of specialized disciplines, and few individuals have expertise in all aspects of the work.

The procedures for dealing with these data are evolving—there is no one “right” way to proceed.

It is my opinion that this field is progressing in a healthy manner.

As in all scientific endeavors, research reported in the scientific literature is often “work in progress” aimed at other investigators, not always to be taken as individual calls for action in the policy community.

With this as context, the committee considered the voluminous literature pertinent to its charge and received briefings and written contributions from more than two dozen people.

We have organized our report knowing that we have at least two different audiences—the science community and the policy community.

The principal conclusions of the committee are listed in the Summary and explained in the Overview using nontechnical language.

More extensive technical justifications for the committee’s conclusions, including references, are presented in the chapters that follow.

Finally, let me thank the members of the Committee on Surface Temperature Reconstructions for the Last 2,000 Years.

The committee worked tirelessly to assess the status of this field of research so that the public can see exactly what is involved, what we currently know about it, and what the prospects are for improving our understanding.

We have tried to make clear how this piece of the climate puzzle fits into the broader discussions about global climate change.

***

Gerald R. North, Chair

Committee on Surface Temperature Reconstructions for the Last 2,000 Years

And there is a 19 page Executive Summary PDF :

PDF EXECUTIVE SUMMARY

***************************Excerpt from beginning of the Summary****************************

Because widespread, reliable instrumental records are available only for the last 150 years or so, scientists estimate climatic conditions in the more distant past by analyzing proxy evidence from sources such as tree rings, corals, ocean and lake sediments, cave deposits, ice cores, boreholes, glaciers, and documentary evidence.

For example, records of Alpine glacier length, some of which are derived from paintings and other documentary sources, have been used to reconstruct the time series of surface temperature variations in south-central Europe for the last several centuries.

Studying past climates can help us put the 20th century warming into a broader context, better understand the climate system, and improve projections of future climate.

Starting in the late 1990s, scientists began combining proxy evidence from many differ- ent locations in an effort to estimate surface temperature changes averaged over broad geographic regions during the last few hundred to few thousand years.

These large-scale surface temperature reconstructions have enabled researchers to estimate past temperature variations over the Northern Hemisphere or even the entire globe, often with time resolution as fine as decades or even individual years.

This research, and especially the first of these reconstructions published in 1998 and 1999 by Michael Mann, Raymond Bradley, and Malcolm Hughes, attracted considerable attention because the authors concluded that the Northern Hemisphere was warmer during the late 20th century than at any other time during the past millennium.

Controversy arose because many people interpreted this result as definitive evidence of anthropogenic causes of recent climate change, while others criti- cized the methodologies and data that were used.

In response to a request from Congress, this committee was assembled by the National Research Council to describe and assess the state of scientific efforts to reconstruct surface temperature records for the Earth over approximately the last 2,000 years and the implica- tions of these efforts for our understanding of global climate change.

Figure S-1 shows a compilation of large-scale surface temperature reconstructions from different research groups, each using its own methodology and selection of proxies, as well as the instrumental record (beginning in 1856) of global mean surface temperature.

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See the PDF

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