To: Dr. B.D. Santer, Livermore June 11, 1996 Dear Ben: I want to reply to your email letters of June 5 and 7 in some detail, to allay your concerns and avoid misunderstandings. 1. I learned about the Chapter 8 text changes (which you made between its acceptance and its printing) from material mailed out by the Global Climate Coalition on May 17. Included there were the Oct 9, 1995 draft and the printed version of Chap 8, as well as a covering memo from Don Rheem "Revisions to Pre-approved IPCC Documents" and an analysis of the changes entitled "The IPCC: Institutionalized "Scientific Cleansing". The GCC did a careful comparison of the two versions of Chap 8; the fact that they are an industry group cannot and should not be used to invalidate their work. 2. I am persuaded that the revisions have altered the tone of Chapter 8 and made it conform more closely to the IPCC Summary. Your view, obviously, is quite different; but then again, you would not be considered as an unbiased party. My recommendation is that the GCC should mail their analysis to you and your co-authors so that you can understand their point of view. 3. I have relied on the GCC's representation that the changes were not in accord with IPCC procedures. This question was put to you when you and Wigley spoke here on May 21. Your answers did not satisfactorily explain whether and when the other lead authors were consulted or informed of these changes, and whether they approved. I have recently called both Barnett and Anyamba to get my own answer to this question. But since this legality is not my concern, I will simply encourage you to settle the matter directly with the GCC, the editor of Energy Daily, and anyone else who might be involved. 4. You asked about my Feb 2,'96 letter to Science. It was prepared in Dec 1995. At that time, your Climate Dynamics paper had not been published; it was certainly not available for the Oct '95 draft of Chap 8. Hegerl's quoted paper may still not be in print. I consider the Aug '95 Mitchell paper to be a pioneering experiment, but not capable of answering the question. In other words, I fully support your general method of looking for a trend in correlation that would show a "fingerprint" emerging from the noise--even though I may question your conclusions. 5. In this connection, however, I am somewhat surprised by the paper prepared by you and Wigley for the May 21 seminar. Figure 3(a) shows only the (positive) 50-year linear trend, but not the zero and negative trends of figure 10 in your Climate Dynamics paper. I would judge that the most relevant trend line should be one starting around 1960 when data coverage increased globally.