Wikipedia discusses the declarations at length, including the history of the 1995 and 1997 declarations, their sponsors and the many issues surrounding the dubious qualifications and counts of their signatories.

This online comment from Christian Jensen discusses a 1997 Danish broadcasting Company (DR1) investigation of the signatories to the declarations in which it was discovered that the large majority have little or no climate science background and the few that do have ties to polluting industries. At the time, Jensen was a PhD. Student studying climate modeling at the Danish Meteorological Institute.

Despite its many credibility problems the Far-Right is still trying to dress up the declarations in new clothing and sell them to an uncritical public. This is a year 2005 “update” posted at the web site of its primary sponsor, the Science & Environmental Policy Project (SEPP). The second link is to an updated list of signatories which includes all but 33 (which as of this writing are pending verification that they still agree with the declaration text).

The 2005 version is noteworthy in that it continues to claim that “many climate specialists now agree that actual observations from weather satellites show no global warming whatsoever—in direct contradiction to computer model results.” In fact, this weather satellite record has for years been represented by multiple analysis products of which only one (from the University of Alabama, Huntsville, or UAH) has ever disagreed with climate model predictions. Needless to say, the SEPP and other Far-Right interests carefully avoid the others. In 2005 it was discovered that the UAH analysis contained a math error which introduced a spurious cooling into its temperature trend (specifically an incorrect sign applied to the diurnal drift correction for one of the satellites in the series). The UAH team acknowledged the error, and after it was corrected their results are now also in agreement with the global warming predictions of climate models. A full report on the weather satellite record including a discussion of the updated results was published by the U.S. Climate Change Science Program in May 0f 2005, and the research that uncovered it was published in the journal Science two months later (Mears & Wentz, Science, 2005).

This discovery received a great deal of attention in the scientific community and the media. The USCCSP report and the Mears & Wentz paper were both widely circulated and are easily available.

And yet that same year—and indeed to this very day—the SEPP and other Leipzig Declaration proponents are still trying to argue that weather satellites disprove global warming!