Close Encounters of the Absurd Kind

“Our ability to quantify the human influence on global climate is currently limited because the expected signal is still emerging from the noise of natural variability, and because there are uncertainties in key factors. These include the magnitude and patterns of long term natural variability and the time-evolving pattern of forcing by, and response to, changes in concentrations of greenhouse gases and aerosols, and land surface changes”.

Contrary to Mr. Pearce’s assertion, important caveats did “make it to the summary for policy-makers”. And the “discernible human influence” conclusion of both Chapter 8 and the Summary for Policymakers has been substantiated by many subsequent national and international assessments of climate science.

There were several reasons why Chapter 8 was a target for unfounded “scientific cleansing” allegations. First, the Global Climate Coalitions’s “scientific cleansing” charges were released to the media in May 1996. At that time, Cambridge University Press had not yet published the IPCC Second Assessment Report in the United States. Because of this delay in the Report’s U.S. publication, many U.S. commentators on the “scientific cleansing” claims had not even read Chapter 8 – they only had access to the GCC’s skewed account of the changes made to Chapter 8. Had the Second Assessment Report been readily available in the U.S. in May 1996, it would have been easy for interested parties to verify that Chapter 8 incorporated a fair and balanced discussion of scientific uncertainties.

Second, the “pre-Madrid” version of Chapter 8 was the only chapter in the IPCC Working Group I Second Assessment Report to have both an “Executive Summary” and a “Concluding Summary”. As discussed in the next section, this anomaly was partly due to the fact that the Lead Author team for Chapter 8 was not finalized until April 1994 – months after all other chapters had started work. Because of this delay in getting out of the starting blocks, the Chapter 8 Lead Author team was more concerned with completing the initial drafts of our chapter than with the question of whether all chapters in the Working Group I Report had exactly the same structure.

The reply of the Chapter 8 Lead Authors to the Energy Daily story of May 22, 1996 pointed out this ‘two summary’ redundancy, and noted that:

“After receiving much criticism of this redundancy in October and November 1995, the Convening Lead Author of Chapter 8 decided to remove the concluding summary. About half of the information in the concluding summary was integrated with material in Section 8.6. It did not disappear completely, as the Global Climate Coalition has implied. The lengthy Executive Summary of Chapter 8 addresses the issue of uncertainties in great detail – as does the underlying Chapter itself.”

The removal of the concluding summary made it simple for the Global Climate Coalition to advance their unjustified “scientific cleansing” allegations. They could claim ‘This statement has been deleted’, without mentioning that the scientific issue addressed in the deleted statement was covered elsewhere in the chapter.

This was my first close encounter of the absurd kind.

The 1995 IPCC Report: The “political tampering/corruption of peer-review” allegation

The second allegation is that I was responsible for “political tampering”. I like to call this “the tail wags the dog” allegation. The “tail” here is the summary of the Chapter 8 results in the IPCC Summary for Policymakers, and the “dog” is the detailed underlying text of Chapter 8.

In November 1995, 177 government delegates from 96 countries spent three days in Madrid. Their job was to “approve” each word of the four-and-a-half page Summary for Policymakers of the IPCC’s Working Group I Report. This was the report that dealt with the physical science of climate change. The delegates also had the task of “accepting” the 11 underlying science chapters on which the Summary for Policymakers was based. “Acceptance” of the 11 chapters did not require government approval of each word in each chapter.

This was not a meeting of politicians only. A number of the government delegates were climate scientists. Twenty-eight of the Lead Authors of the IPCC Working Group I Report – myself included – were also prominent participants in Madrid. We were there to ensure that the politics did not get ahead of the science, and that the tail did not wag the dog.

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