Global Lower Tropospheric Temperatures (1979-1996)| -0.2 -0.3 -0.4 -0.5 -0.6 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 YEAR 1 0.8 0.6 0.4 0.2 Global Lower Stratospheric Temperatures (1979-1996)| 83 ETChichon Mt. Pinatubo Figure 2. (Top) Seasonally adjusted monthly variations of the global 0.8 0.0 -0.8 0.8 0.0 EC.PN DT-8.85 1.40 EC LED- 4 TM. AM. EX -14. 0.110 0.87 ENSO-84 7-91 6 Th-8.05 T MSU T2R TREND/DECADE = -0.051 F79,80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 -0.8 81 82 8 83 1 84 85 86 87 88 89 90 91 92 93 94 95 96 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 T -79 80 81 82 83 84 85 1 86 -0.8 0.8 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 Figure 3. (Top). Monthly global average temperature anomalies (as in Fig. 2) for the lower troposphere (°C). (Second) The influence of tropical Pacific temperatures on the global temperature. (Third) The global temperature after the influence of Pacific temperatures has been removed. (Fourth) Influence on global temperature of volcanic events. (Fifth) Global temperature variation once Pacific Ocean and Volcanic effects have been removed. Mr. BARTLETT. Well, thank you very much. I know our Chairman wanted to return for the questions, so let me ask you all in the interim between now and when he returns if there are any of you who would like to challenge the position or statements of any of the other of you? Yes, sir? Dr. MACCRACKEN. Well, I want to try and clarify this issue of scientific consensus. It is true, as Dr. Davis said, that science doesn't operate that way. Science operates in a very contentious way of arguing and looking for challenges and uncertainties. But periodically, on issues of public importance, science has to come together in some way to provide information for decisionmakers. And the best way we have figured out how to do that is to try and have something like what the IPCC has created, which is to create panels on various questions and then to try and write a report that is encompassing of the range of views. IPCC does not come up with a single answer. They come up with quite a wide range of answers, actually, because they recognize that there is uncertainty. So it's important to understand that what a consensus does is the way in which the scientific community is speaking, it's certainly proper to ask for what is going on in the scientific community and what's happening. But the best advice, the collective advice, is coming from assessments. Thank you. Dr. MICHAELS. If I could respond to that. Mr. BARTLETT. Yes, sir. Dr. MICHAELS. Thank you. I'm not on mike, but I've heard that I'm loud enough that it doesn't matter. [Laughter.] What Mike says is well and good and has merit. But you need to understand the process whereby the scientific consensus is achieved. If we took 100 scientists and put them in a room and asked them their opinion about a subject in which in fact the truth was not known, I assure you that the consensus that would emerge from that room would be some regression to the mean opinion of the group of scientists. That would not necessarily be what is truth. Let me give you an example from the Intergovernmental Panel on Climate Change. In 1990, they produced a report in which they estimated that the temperature between then and the year 2025 would rise by 1.0 degree celsius. That's a third of a degree per decade. Scientists who reviewed that, like myself, said that this simply can't be correct because the planet is not warming at such a proper rate. I think I have to stop talking now. [Laughter.] Mr. BARTLETT. No, that's fine. I just asked them if any of them wanted to challenge the statement of any of the other of them. Chairman WALKER. Okay. Very good. Mr. BARTLETT. And they're responding to that now. Dr. MICHAELS. Can I finish my statement? Chairman WALKER. Please do. Dr. MICHAELS. It's as brief as I can possibly be, which is probably far too long. And the scientists that made this statement, many of them, including myself, hypothesized that the reason that it wasn't warming up was that something was interfering with the warming that was causing an increase in cloudiness, sulfate aerosol being an example of something that can do this. Those scientists were not included very much at all in the 1990 consensus. When we got to 1995, we find out that it is now the consensus that in fact the climate models that were engaged in the 1990 and 1992 processes, 1992 being created specifically for the Rio Earth Summit, were in fact predicting too much warming. So that the scientists that were marginalized from the consensus in fact turned out to be right. I would urge that when you look at this problem of scientific consensus, that you not only look at the consensus, but you also look at the detractors or the people who criticize that consensus, who do it in a way that seems internally consistent. They may in fact turn out to be right. Chairman WALKER. Is there anybody else who would like to respond to that which they heard in terms of the testimony? Dr. Lindzen? Dr. LINDZEN. I don't know. I guess this is on. But in terms of Mike MacCracken's discussion of the IPCC, and I guess Bob Watson, I do think somewhat, not in disagreement with Mike that the IPCC process, however flawed, does have a very wide range of statements. I would argue that the policy-maker summary and the executive summaries tend to misrepresent this. But I think the real problem we have at least is these are public documents which are not widely read. One has a great many groups claiming to tell the public what these documents say. I think that may be a more serious issue than what they actually say. We've had several ads for the Union of Concerned Scientists say, don't believe anyone who disagrees with the catastrophic scenario. Believe us. We represent the IPCC. I don't think that there was anything in the procedure that suggested that they were the representatives of the IPCC. Chairman WALKER. Well, at least, I would say to you, you were only called junk scientists by them. We've been referred to as potted plants. [Laughter.] Dr. LINDZEN. Yes, that's right. Chairman WALKER. Dr. MacCracken? Dr. MACCRACKEN. Mr. Chairman, one of the things that we have worked very hard on this year, as the government has reviewed the IPCC process, has been to be exceedingly open with it, to make sure that the documents were widely circulated. We in fact made them available through a Federal Register notice so that people could review the draft. There was indeed, perhaps, too narrow a perspective taken several years ago. We've learned from that perspective and have opened up the process. All of the panelists here are in fact listed as contributors to the IPCC report, or in some case authors, and several of them contributed to at least several of them contributed to the review process. So we've worked very hard to make IPCC a very open process to try and get the best possible information. Thank you. Chairman WALKER. Thank you. Dr. Davis? Dr. DAVIS. Yes, I'd like to comment on that with a specific example. I am one of the people who was a contributor to the IPCC report and also had an opportunity to provide my comments on the first draft version. I was asked to submit a several-page report on climate atmospheric circulation, as I just talked about. Not only in talking about my research, but that of many other scientists, all in the referee literature. My general view of atmospheric circulation change has been that there is no evidence by looking at that record to indicate that atmospheric circulation has changed in response to increasing concentrations of CO2 and other trace gases. I got the draft version of the IPCC report back with my chapter and it contained absolutely none of the information that I submitted. My initial thought was perhaps what I submitted, all of which is in the refereed literature, was not in line with what the authors of that chapter believed to be the scientific consensus, if you will, on that particular issue, or with the goals of that chapter. In reading the comments, I did however find a number of people who had the opposite view, and some of these publications were not even submitted for peer review in the scientific literature. This led me to go through the entire IPCC's document and count the number of citations that were either not in the literature, some of which personal communications, things that were to be submitted for publication. Ladies and gentlemen, this is not how science works. Science works, as we've all said, by continuous review and criticism of other people's works. Some 30 percent of all the citations in the IPCC report were unavailable to me when I was reviewing the doc ument. That is not a scientific document. It's a public policy document. I sent these comments back to the IPCC in the hopes that they might change the last draft of the report, and in fact, none of these changes were incorporated. So I look at the IPCC with significant skepticism. Dr. WATSON. Thank you, Mr. Chairman. There's a fundamental rule in the IPCC that we either use peerreviewed literature or preprints so it can be to be submitted, as long as that data or that preprint is available for review. |