accuracy of the coring would have been validated. Instead, the reproduction of a record that was nearby but separate gave both support to the main results, but also allowed the groups to discover a mix-up in dating prior to 100,000 years ago in one of the two cores. So drilling two different ice cores, rather than drilling from the same source twice, proved to be a far more valuable use of the available funding and resources.

The proponents of this idea also ignore the near-impossibility of its implementation. How would scientists be persuaded to replicate the unpublished work of others? What would their incentives be to conduct this work quickly, especially if it meant sacrificing the time researchers would prefer to spend on their own work? Would every study be subject to replication? Or only important studies? And who would decide which studies required replication prior to publication? Who would pay for these replications? Would the government pay for them? Is Congress prepared to double the size of research budgets for all of the major scientific funding agencies (e.g. NSF, NIH, NOAA, etc.)? And these practical problems are only the tip of the iceberg.

My essential plea here is that Congress should not fix that which is not broken. Since Copernicus' time the scientific process has successfully weeded out the wheat from the chaff. It would be dangerous for Congress or any government body to tamper with that process.

There is another element of this question which raises a deeply troubling matter with regard to Dr. Wegman's failure to subject his work to peer review, and Wegman's apparent refusal to let other scientists try to replicate his work. Professor David Ritson, Emeritus Professor of Physics, Stanford University, has found error in the way that Dr. Wegman models the "persistence" of climate proxy data. Interestingly, this is the same error Steven McIntyre committed in his work, which was recently refuted in the paper by Wahl and Ammann, which was in turn vetted by Dr. Douglass Nychka, an eminent statistician. Dr. Ritson has determined that that the calculations that underlie the conclusions that Dr. Wegman advanced in his report are likely flawed. Although Dr. Ritson has been unable to reproduce, even qualitatively, the results claimed by Dr. Wegman, he has been able to isolate the likely source of Wegman's errors. What is so troubling is that Dr. Wegman and his co-authors have ignored repeated collegial inquiries by Dr. Ritson and apparently are refusing to provide any basic details about the calculations for the report (see Attachments 3 and 4 to this Response). It would appear that Dr. Wegman has completely failed to live up to the very standards he has publicly demanded of others.

Moreover, the errors that Dr. Ritson has identified in Dr. Wegman's calculations appear so basic that they would almost certainly have been detected in a standard peer review. In other words, had Dr. Wegman's report been properly peer-reviewed in a rigorous process where peer-reviewers were selected anonymously, it likely would not have seen the light of day. Dr. Wegman has thus unwittingly provided us with a prime example of the importance of the peer review process as a basic first step in quality

RESPONSE FOR THE RECORD OF DR. JOHN R. CHRISTY, PROFESSOR AND DIRECTOR, EARTH SYSTEM SCIENCE CENTER, NSSTC, UNIVERSITY OF ALABAMA IN HUNTSVILLE

28 August 2006

Hon. Ed Whitfield

Chairman

Subcommittee on Oversight and Investigations

Committee on Energy and Commerce

2125 Rayburn House Office Building Washington DC 20515-6115

Dear Rep. Whitfield,

Thank you for the opportunity to appear before your Subcommittee to address issues of global climate change. I especially thank you for the opportunity to clarify some of the material that was entered into the official record which appeared to contradict my testimony. I assure you that what I presented was accurate as to my experiences and understanding of climate change in general and dataset construction in particular.

I will be happy and available to answer any further questions regarding my appearance.

Sincerely,

John R. Christy

Director, Earth System Science Center

Alabama State Climatologist

University of Alabama in Huntsville

Questions from Rep. Whitfield for John R. Christy

(1) During the hearing, Mr. Waxman introduced into the hearing record a letter from Frank J. Wentz regarding your sharing of code with Remote Sensing Systems 9RSS). Please explain your interactions with RSS (and Mr. Wentz) and subsequent interactions with Dr. Mann, as mentioned in your testimony.

(1) Answer

In the Hearing before the Subcommittee on Oversight and Investigations of the House Committee on Energy and Commerce on 27 July 2006, I testified about our cooperation with Remote Sensing Systems (RSS) regarding sharing of satellite data and code.

Mr. Waxman introduced into the record a letter from Mr. Frank Wentz of RSS which included an email from me to Mr. Wentz, over 4 years old, implying an apparent lack of cooperation. The problems here are (a) that this March 2002 email to Mr. Wentz from me was simply the first in a long series of emails in which we indeed cooperated, and (b) that this exchange related to a different dataset than the one I was speaking of in my testimony. The following discussion describes the way these two datasets were examined by RSS.

Mid-Tropospheric (MT) Temperature Product

Another RSS Scientist, Dr. Carl Mears (not Dr. Mann), began constructing an MT product from the raw microwave digital counts in early 2002, following much of our published methodology. There were some discrepancies between our two results. Mr. Wentz asked for the code with which we constructed our MT data so as to resolve these differences. As stated in my first email on the subject, shared by Mr. Waxman in Mr. Wentz's letter, I declined to send the code for the reasons given. However, there were many further exchanges of information (in terms of the Hearing language: there were discussions about the "algorithms") to the point that RSS understood the three main differences between our two datasets. Mr. Wentz's description of “trial and error” in his letter in this process left out the important point that we were in constant communication on the details and subtleties of the dataset construction process.

During this time, we discussed at great length matters concerning (1) the methodology of calculating the strength of the target-temperature effect, (2) the methodology of determining intersatellite biases and to a lesser extent (3) the adjustments for the satellites' east-west drifting (diurnal effect.)

At a conference in Asheville NC, (Oct. 2003) Dr. Mears presented a talk entitled "Understanding the difference between the UAH and RSS retrievals of satellite-based tropospheric temperature estimate" and stated he was satisfied as to having understood the main reasons for the differences between our two datasets. Indeed in this presentation, Dr. Mears used some of the adjustment files we had provided to them to help answer questions of how our adjustment process worked (i.e. diurnal drift files.) He also displayed our target factor calculations, again provided to RSS, along with a detailed description of their computation. It was clear we had provided information to understand the discrepancies.

RSS was also able to publish these findings and results (Mears et al. 2003). I was a reviewer of that paper and recommended publication. In my view, this closed the episode on this dataset.

Lower Tropospheric (LT) Temperature Product

In 2005, Dr. Mears also led in the development of a different temperature product, LT, which UAH had been producing since 1992. He addressed the issues of hot target

calibration coefficients and intersatellite biases to his satisfaction but was unable to replicate our diurnal effect. He asked for more information and we supplied the appropriate section of the code and intermediate adjustment files so he could test the code against the output. With these in hand he was able to discover the artifact in the algebra which created the error most visible in the tropics.

That we supplied these items is inarguable as the paper published by Mears and Wentz (2005) in Science displays the UAH adjustment files. Additionally, even though we did not know the outcome of their study at the time, I granted permission to publish our files as shown by this following exchange between Dr. Mears and myself on 13 May 2005 in which he responds to me for being open in this way.

13 May 2005 8:41 p.m.

Hi Carl:

Anyway, something jogged my memory this morning that you had asked about using the UAH diurnal adjustments in a paper, and I didn't respond with a firm answer. Sorry. I think it would be fine to use and critique ... that's sort of what science is all about.

[John Christy]

13 May 2005 1:58 p.m.

Hi John

Thanks for permission -- I strongly approve of your view of science expressed [above]. I think that things that aren't nutty or poorly explained should be published in the open literature without too much fuss, so that they can then be commented on..... Of course, different people have different opinions about what constitutes nutty.

You[r] global diurnal effect agree[s] pretty much with mine, but it's the *opposite* sign. The real difference is in the tropics. I suspect the same calculation for 20S to 20N will show a much larger effect. With the modelbased diurnal correction, the big disagreement with the surface in the tropics goes away.

[Carl Mears Remote Sensing System]

So, the apparent contradiction between my testimony and the letter from Mr. Wentz sprang from a misunderstanding of how two different datasets were being addressed. One (MT) was solved without sharing the specific code but for which we did supply ancillary data files and considerable information. The other (LT) needed parts of the code to resolve the discrepancy. In the Hearing, Mr. Waxman dealt with the former while I dealt with the latter. In both cases, however, UAH did cooperate with RSS.

Mears, C.A., M.C. Schabel, and F.J. Wentz, 2003: A reanalysis of the MSU channel 2 tropospheric temperature record. J. Climate, 16, 3650-3664.

Mears, C.A. and F.J. Wentz, 2005: The effect of diurnal correction on satellite-derived

(2) As you were a member of the National Research Council panel that recently issued the report on millennial temperature reconstructions:

(a) Where in the report did the panel describe "plausible" as suggesting roughly a 2/3rds probability of being correct.

(b) In the report, did the panel attach probability estimates to the term "plausible"?

(c) Why did the panel choose to use the term “plausible,” as opposed for example to terms such as “likely”, to describe confidence in millennial temperature reconstructions?

(2a) Answer

The report did not intend for “plausible” to be equated with “2/3rds” probability of being correct. My view,as a panel member, is that "plausible" was chosen to indicate a lack of quantifiability in describing confidence in pre-1600 temperatures.

(2b) Answer

"Plausible" was chosen precisely because it implied that probability estimates could not be assigned to pre-1600 temperature estimates due to (a) the limited amount of proxy information available and (b) the unknown confidence with which these proxy records may determine temperature. The current proxies are mostly consistent with the notion that pre-1600 temperatures were cooler than late 20th century temperatures, but the evidence is still too meager and uncertain.

(2c) Answer

As a member of the IPCC 2001 Lead Author team I outlined in my testimony why the word "likely" was chosen in that document. "Likely" in the IPCC 2001 terminology had an estimated likelihood defined as being at least 2/3rds probable. The NRC panel chose "plausible" for reasons given in (2b) above. My view of the NRC report is that our IPCC statement was inadequate in that the IPCC should have separated the last millennium into two periods with higher than “likely” confidence for post-1600 and lower than "likely" confidence for pre-1600 estimates.

(3) When considering the panel's findings that it is "plausible” that recent decades were the warmest in a millennium, is it correct to interpret that to mean the panel's consensus view was that plausible means roughly 2/3rds probability of being correct, as was suggested in the news reports following the press conference releasing the report?

(3) Answer

I was disturbed when reading the press reports that implied the panel had endorsed with "likely" confidence statements about the pre-1600 temperatures. The panel did not conclude that there was a 2/3rds probability that late 20th century warmth was greater than at anytime prior to 1600. As noted above, there are indications that such is the case, but the data do not allow statements of quantifiable confidence to be made at this point.

(4) In your testimony, you mention your recent study relating to California regional temperature trends and human influences on those trends (Christy et al. 2006a). Please describe the purpose and conclusions of that study.