July 27, 2006

Good afternoon and welcome to a second day of our hearing regarding questions about what we popularly call the "hockey stick" temperature studies and the implications for climate change assessments.

We've reconvened this hearing to accommodate a key person in the matters before us, Dr. Michael Mann, of Penn State University. Dr. Mann was unable to attend the informative session on this subject last week. Although Dr. Thomas Crowley - Dr. Mann's personally recommended replacement - did testify, we are providing Dr. Mann the opportunity to discuss his work and respond to some of the views expressed about his work.

Welcome Dr. Mann, I'm looking forward to your testimony and participation. I hope we can continue to explore some of the broader questions surrounding temperature reconstruction findings, their use in the IPCC assessment, and other issues that prompted our inquiry into this matter last year.

The hockey stick graphic and the underlying studies were influential in a prominent set of findings by the IPCC. In point of fact, from the very first set of findings on the very first page of discussion in its 2001 Summary for Policymakers, the IPCC states that 20th Century temperature increases were likely the largest in 1,000 years and it was "likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year," a phrase that is almost verbatim what Dr. Mann and his colleagues wrote in their 1999 paper. Next to these findings, the IPCC Summary then displays Dr. Mann and his colleagues' hockey stick-shaped temperature graph, which helped place this work prominently into the public eye.

Let me take a moment and make few observations about last week's hearing.

First, through our discussion of both the National Research Council report and the Wegman report, we established that the original studies by Mann and his coauthors were flawed, and could not support the related findings of the 2001 IPCC assessment. Dr. Wegman's independent committee found and reported that Dr. Mann and his coauthors incorrectly applied a statistical methodology that would preferentially create hockey stick shapes. Dr. Wegman also found that more recent methodologies used in temperature reconstruction studies may also generate problematic biases when determining temperature histories.

The National Research Council, upon its review of the current state of science on this subject, likewise found that the hockey stick studies could not support the 2001 IPCC finding drawn from them. The NRC panel's review determined that Dr. Mann made, in the words of the NRC witnesses, "inappropriate" choices, and that the panel had "much the same misgivings about [Dr. Mann's] work that was documented at much greater length by Dr. Wegman."

Moreover, both the NRC and Wegman reports essentially corroborated the main criticisms raised by the McIntyre-McKitrick studies about Dr. Mann's initial hockey stick studies.

While much attention was given to Dr. Wegman's social network analysis, I think it is only fair to observe the limits of what he was trying to illustrate, as he himself tried to explain.

Dr. Wegman was not seeking to impugn the integrity of any of the scientists who work in this area, but it is clear that peer review somehow failed to pick up the flaws in the hockey stick studies. Dr. Wegman simply raises the possibility that, given the evident publishing relationship among the authors of many of the relevant works, combined with the failure to involve statisticians, Dr. Mann's peers may have been too close to the topic to scrutinize the studies as rigorously as they might have. Whatever the case, Dr. Mann's peers failed to catch the errors Wegman, the NRC, and McIntyre identified.

This failure, as Dr. von Storch suggested last week, may be less an issue with the community of paleoclimatologists, than with the journal editors themselves. The Committee can remain cautious about Dr. Wegman's social network analysis, as he is, and still legitimately raise the broader question about the rigor of review and breadth of reviewers in this field.

Finally, I think it is important to note that virtually everyone at the hearing last week - both members and witnesses - took the view that criticisms of the hockey stick studies or of the peer-review and assessment process should not be construed as a judgment about the changes in global temperatures.

Rather, the issues at hand concern legitimate questions about the rigor of scientific analysis, the results of which ultimately reach policy makers. The hockey stick story provides a clear case study into the lack of proper scrutiny, and the questions last week about the independence of peer-review, or the "gate keeping" issues, were entirely legitimate. I hope that as we proceed today, we keep this in mind. And I hope that we can all reach agreement on ways to improve the process.

Let me note that we have, in addition to Dr. Mann, both Dr. Wegman and Mr. McIntyre returning to recap their testimony and to answer questions related to their work, if necessary. Both of them graciously agreed to adjust their busy schedules, including family and work obligations, to return today at our request so that Dr. Mann could confront his critics. Thank you very much for coming back.

We have a few additional panelists as well. As we were preparing this panel, our minority counterparts requested an additional witness. In the event, we accommodated their requests so that we could have as informative and balanced a panel as possible.

So let me welcome Dr. John Christy, the Director of the Earth System Science Center and Alabama State Climatologist at the University of Alabama, Huntsville and Dr. Jay Gulledge, of the Pew Center for Climate Change.

Finally, I'd like to recognize a most-distinguished witness, Dr. Ralph Cicerone, President of the National Academy of Sciences. Dr. Cicerone has been instrumental in the National Academies' focus on climate change research in recent years. Indeed, he chaired the National Research Council's 2001 report for President Bush that helped pave the way for the United States to conduct its own climate change assessments.

Welcome Dr. Cicerone, and welcome all the witnesses, I look forward to another informative panel.

I now yield to my distinguished Ranking Member, Mr. Stupak.

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