The KGB Oracle Forums General Public Discussion (SPECIAL ACCESS) KGB Political Debate Central Climate change!

Summary of the opinions from climate / earth scientists regarding climate change.
The Doran & Zimmerman study was done for a master's thesis and involved a 9-question survey. The 2009 peer reviewed publication that followed the study reported on 2 of the 9 questions. The study found, in part, that 96.4% of "climatologists who are active publishers on climate change" agree that mean global temperatures have risen "compared with pre-1800s levels", and that 97.4% (75 of 77) agree that human activity "is a significant contributing factor" in temperature change. The study concludes the distribution of answers to those survey questions implies that debate on the "role played by human activity is largely nonexistent" amongst climate experts.
The 97.4% result reflects the opinions of 77 individuals selected out of a total of 3,146 self-selected respondents based on a total population of 10,257 individuals who were invited to participate in the survey.
Doran & Zimmerman 2009 source:
http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf
The Anderegg et al 2010 source defined a scientist's expertise as determined by his or her number of climate publications. The top 50 scientists considered CE ("convinced by the evidence" in the terminology of the authors) wrote an average of 408 articles each which were submitted to and successfully published by climate journals. Scientists were counted as UE ("unconvinced by the evidence") if having signed a public "statement strongly dissenting from the views of the IPCC." That resulted in a list of 472 UE scientists, of whom 5 were among the 200 most-published scientists in the study's sample, amounting to 2.5% when the other 195 (97.5%) were counted as CE.
That study's sample included 903 scientists counted as CE ("convinced by the evidence"). Scientists were assumed to be CE when in the list of those credited by the IPCC as having done research utilized by AR4 Working Group I. Such an assumption resulted in a list of 619 names, which, after adjusting for duplication, became a total of 903 when also adding in those who signed one of several statements supporting the IPCC.
The results presented in this study are based on a compiled researcher list which the authors describe as being "not comprehensive nor designed to be representative of the entire climate science community."
Anderegg 2010 source:
http://www.pnas.org/content/early/2010/06/04/1003187107.full.pdf
http://www.pnas.org/content/suppl/2010/06/07/1003187107.DCSupplemental/pnas.201003187SI.pdf