Jeff Judson is mostly correct, didn't he get all the details quite right. He wrote, "NASA's third bit of “proof” cites a 2008 study by Maggie Kendall Zimmerman, then a master's candidate at the University of Illinois, and her professor, Peter Doran. The shoddy survey asked 3,146 researchers who listed “climate science” as an area of expertise two questions about the Earth's climate. Only 79 scientists responded, of which 97 percent said “yes.”"
Actually, Doran & ZImmerman surveyed 10,257 Earth Scientists at academic and government institutions, of whom 3146 responded.
But even though academic and government institutions are notoriously left of center, he didn't find the result he was seeking. In spite of the fact that they asked "gimme" questions, designed to elicit the answers which Prof. Doran wanted, only about 3/4 of the respondents gave the answers he wanted.
Doran's claims are based on the answers to just two questions, both of which were so uncontroversial that even I, and most other climate change skeptics & "lukewarmers," would give the "consensus" answers.
The first question was:
1. "When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?"
Since the 1700s were during the Little Ice Age, the climate has obviously warmed since then (which has nothing to do with anthropogenic climate change). But, remarkably, only 90% of those surveyed said "risen."
Those who answered either "risen" or "fallen" were asked a second question:
2. "Do you think human activity is a significant contributing factor in changing mean global temperatures?"
Note that those who answered "remained relatively constant" to the first question were not asked the second question.
Also, note that Doran did not ask whether human activity is the main factor causing climate change, nor whether it is worrisome. He only asked whether human activity is a "significant contributing factor" to climate change. That encompasses both GHG-driven warming and particulate/aerosol-driven cooling. It could also be understood to include Urban Heat Island (UHI) effects.
Even a climate skeptic like me would have had to have answered "yes" to that question. But only 82% of those who were asked the 2nd question answered "yes."
Since Doran didn't report how many people gave "wrong" answers to either question, we can't tell exactly how many climate skeptics Doran & Zimmerman identified. But if we very reasonably assume that at least 3/4 of those who gave undesired answers to the first question answered that temperatures had "remained relatively constant" (rather than "fallen"), and so were not asked the 2nd question, we can calculate that at least (0.18 + 0.075) / 1.075 = 23.7% of the scientists who responded must have given "skeptical" answers to one or both questions.
Some "consensus," eh?
76% wasn't the "consensus" Prof. Doran wanted. So, to reach his 97% consensus goal, Prof. Doran discarded all of the responses except the 79 specialists in climate science.
Yes, you read that correctly: 97.5% of those who responded were excluded after their responses were received. Of 3146 responses received, only 79 responses were considered when calculating the "consensus."
Note: asking only the most narrow specialists in climate science about the climate scare is like asking only homeopaths about the efficacy of homeopathy, or asking only Baptists about baptism by immersion: they're the worst people to survey, because they're the least impartial.
But Prof. Doran still didn't get the answer he wanted. ONly 76 of the 79 answered "risen" to the first question: "When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?"
That's only 96.2%. Close, but no cigar. That wasn't quite sufficient to reach the magic "97%." So to reach that threshold on the 2nd question, he excluded two respondents (out of 79) who gave "wrong" answers to the first question.
You see, two of the 79 apparently answered "remained relatively constant" to the first question, so they were not asked the second question. That's fine: they had already identified themselves as skeptics, obviously, and it makes no sense to ask someone what caused a change that you've just said didn't occur. But Doran should have counted them among the skeptics, and he didn't.
75 of the remaining 77 (97.4%) answered "yes" to the second question: "Do you think human activity is a significant contributing factor in changing mean global temperatures?" That's where the "97%" number comes from, for which Doran is widely cited as the source. But it is wrong.
Actually, only 74 or 75 of 79 answered both "risen" to the first question and "yes" to the second question. That's 93.7% or 94.9%, not 97%.
That's in spite of the fact (3146-79) / 3146 = 97.5% of the respondents were excluded after the responses were received, and in spite of the fact that neither of the two questions actually addressed anthropogenic global warming.
It is unfortunate that they didn't ask an actual question about Anthropogenic Global Warming. They should have asked something like, "Do you believe that emissions of CO2 from human activities, such as burning fossil fuels, are causing dangerous increases in global average temperatures?" or (paraphrasing a politician) "Do you believe that climate change is real, man-made and dangerous?" But if they'd asked a question like that, they'd not have gotten the answer that Doran wanted.