A Comment by Christian Jensen ^{Note 1}

How many climate researchers support the "Leipzig Declaration"?

According to Fred Singer (letter to naturalSCIENCE), Kevin Trenberth's claim (naturalSCIENCE article Global warming: It's happening) that more than 2000 scientists were represented in the Scientific Assessment of the 1995 Intergovernmental Panel on Climate Change (IPCC95) is the repetition of a long-standing fabrication. "There are," he says, "only about 100 climate scientists in the IPCC's listing, which includes economists, political scientists, government functionaries, and public relations specialists." Whatever the merit of Singer's charge, it prompts scrutiny of the list of over 100 "bone-fide experts" who Singer claims have signed his so-called Leipzig Declaration (1), a document expressing skepticism about the importance of greenhouse warming caused by rising atmospheric carbon dioxide concentrations.

Such an examination has been undertaken by Danish Broadcasting Company (DR1) journalist, Øjvind Hesselager (2). In late 1997 he attempted to contact every signatory (82 at the time) to the "Leipzig Declaration." Of 33 European signatories:

• there were four he was unable to locate
• twelve denied having signed, and of these, some had not even heard of the "Leipzig Declaration"
• many signatories were not qualified in fields even remotely related to climate research. They included medical doctors, e.g., H. Metzner; nuclear scientists, e.g., M.J. Higatsberger; and one expert on flying insects, i.e., V. Svidersky
• some signatories had financial ties to the German coal industry or the Government of Kuwait (R. Balling and P. Michaels).

These are hardly reliable authorities on climate research.

Confronted with these facts, Singer removed many from the list, although not the five mentioned by name above (Dr. Metzner apparently played a central role in compiling the list of signatories). Other names were then added to make a total, today, of more than 100.

Of the present signatories:

• twenty-five are TV-meteorologists (here in Denmark, being a TV-meteorologist does not imply any in-depth knowledge of climate research)
• nine do not appear, from the information provided in the published list (2), to be involved in relevant research
• fourteen claim the title "Professor," but the list gives no indication of their academic speciality or institutional affiliation
• forty-two are listed either as an oceanographer, meteorologist, climatologist, or geophysicist or as the employee of an institution involved with climate research. However, in only a minority of cases is it indicated by the list as currently published (1) whether these individuals are actually doing climate research.

If the IPCC95 Scientific Assessment represented only 100 scientists, it is unfortunate that the number has been stated to be 2000. However, the scientists who were represented in the IPCC95 Scientific Assessment are among the best qualified individuals to evaluate mechanisms and impacts of potential climate change. This is more than can be said of many, and perhaps most, of those who have signed, or who are supposed to have signed, the "Leipzig Declaration."

Reference

(1) Signatories to the Leipzig Declaration: http://www.sepp.org/LDsigs.html

(2) A DR1 (Danish Broadcasting Corporation) report concerning the signatories to the Leipzig Declaration: http://www.dr.dk/root/klima/artikler/Bestem/flobby3.htm. In Danish.

¹ Christian Jensen
Ph.D. student (Climate monitoring)
Danish Meteorological Institute
Research Department

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