How the 97% Consensus Figure Was Worked Out
By Dave Burton
The climate debate is not over whether “climate change is real.” That’s a straw-man.
Most climate realists / skeptics agree that climate change is real. But the best evidence indicates that manmade climate change is probably not harmful at all, and certainly is not very harmful.
The best evidence is that anthropogenic climate change is modest and benign, and CO2 emissions are beneficial, rather than harmful.
All of the important harms that are alleged to be caused by man’s CO2 emissions are merely hypothetical. However, the benefits of mankind’s CO2 emissions are large, and well-measured.
Dave Burton's answer to How do I stop obsessing over climate change?
When counting the “consensus” the climate campaigners count most of us “skeptics” and “lukewarmers” as part of their “consensus.” All you need to be part of the “97% consensus” is answer “risen” and “yes” to these two questions, respectively:
Obviously that includes most skeptics and lukewarmers, like me. (Of course in any other context we're “science deniers bought off by big oil and the Koch brothers” — according to the conspiracy theories of the climate campaigners.)
The claim of a 97% consensus among scientists comes originally from an article by Prof. Peter Doran in 2009. Here’s what he did.
FIRST, Dr. Doran wrote just two “opinion” questions for his survey, both of which were “gimmies,” designed to elicit the answers he wanted. (There were also some demographic & background questions.)
The survey pretended to be an attempt to learn about scientists’ opinions, but it wasn’t. Neither question was designed to actually learn anything about scientists’ opinions. Both of the questions were so uncontroversial that even I, and most other skeptics of climate alarmism (a/k/a “climate realists” or “lukewarmers”) would have given the answers he wanted.
SECOND, Doran had his graduate student send the survey to over 10,000 geophysical scientists, but only to people working in academia or government — known bastions of left-of-center politics. Scientists working in private industry, who tend to be more conservative, were not surveyed. That biased the sample, because the climate debate is highly politicized: most conservatives “lean skeptical” and most liberals “lean alarmist” in the climate debate.
They got 3,146 responses.
THIRD, to calculate his supposed “consensus” Prof. Doran excluded all but the most biased respondents: the most specialized specialists in climate science.
That’s a massive, fundamental blunder.
It’s like asking only homeopaths about the efficacy of homeopathy, rather than the broader medical community.
It’s like asking only people working on cold fusion about whether cold fusion works, rather than asking all physicists.
It makes the result completely meaningless. No matter how sketchy the practices in a field, if you ask only practitioners of that specialty you’ll always get strong agreement. Even if you asked astrologers whether astrology works, most would say “yes.”
By screening out all but the most specialized specialists in climatology, Doran excluded over 97% of the geophysical scientists who had answered the survey! Only 79 were left.
That’s right: he pruned 3,146 responses down to just 79.
But even that didn’t get his desired “consensus” figure up to 97%. So,
FOURTH, to calculate his final “97.4%” result, Doran excluded respondents who gave one of the “skeptical” answers to the first of his two questions.
I’m not kidding, he really did.
The first “gimme” question was:
“When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?”
(I would have said “risen” — after all, the 1700s were the Little Ice Age!)
Those who answered “remained relatively constant” were not asked the 2nd question, and they were not counted when calculating his percentage consensus.
That left Doran with just 77 out of 3,146 responses. He used only those 77 for the “97.4%” calculation.
The second question was:
“Do you think human activity is a significant contributing factor in changing mean global temperatures?”
Well, of course it is! That encompasses both GHG-driven warming and particulate/aerosol-driven cooling. It could also be understood to include Urban Heat Island (UHI) effects.
Since just about everyone acknowledges at least one of those effects, I would have expected nearly everyone to answer “yes” to this question. Yet 2 of 77 apparently did not.
It is unfortunate that Doran and his graduate student didn’t ask an actual, legitimate 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 President Obama) “Do you believe that climate change is real, man-made and dangerous?”
Of course the reason Prof. Doran didn’t ask “real” questions like those is that his survey was a scam: Its purpose was NOT to discover anything, it was to support a propaganda talking point.
You can find much more information about the various surveys of scientific opinion on climate change, including source references for everything I’ve written here, on this web page:
http://tinyurl.com/Clim97pct
Most climate realists / skeptics agree that climate change is real. But the best evidence indicates that manmade climate change is probably not harmful at all, and certainly is not very harmful.
The best evidence is that anthropogenic climate change is modest and benign, and CO2 emissions are beneficial, rather than harmful.
All of the important harms that are alleged to be caused by man’s CO2 emissions are merely hypothetical. However, the benefits of mankind’s CO2 emissions are large, and well-measured.
Dave Burton's answer to How do I stop obsessing over climate change?
When counting the “consensus” the climate campaigners count most of us “skeptics” and “lukewarmers” as part of their “consensus.” All you need to be part of the “97% consensus” is answer “risen” and “yes” to these two questions, respectively:
- “When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?”
- “Do you think human activity is a significant contributing factor in changing mean global temperatures?”
Obviously that includes most skeptics and lukewarmers, like me. (Of course in any other context we're “science deniers bought off by big oil and the Koch brothers” — according to the conspiracy theories of the climate campaigners.)
The claim of a 97% consensus among scientists comes originally from an article by Prof. Peter Doran in 2009. Here’s what he did.
FIRST, Dr. Doran wrote just two “opinion” questions for his survey, both of which were “gimmies,” designed to elicit the answers he wanted. (There were also some demographic & background questions.)
The survey pretended to be an attempt to learn about scientists’ opinions, but it wasn’t. Neither question was designed to actually learn anything about scientists’ opinions. Both of the questions were so uncontroversial that even I, and most other skeptics of climate alarmism (a/k/a “climate realists” or “lukewarmers”) would have given the answers he wanted.
SECOND, Doran had his graduate student send the survey to over 10,000 geophysical scientists, but only to people working in academia or government — known bastions of left-of-center politics. Scientists working in private industry, who tend to be more conservative, were not surveyed. That biased the sample, because the climate debate is highly politicized: most conservatives “lean skeptical” and most liberals “lean alarmist” in the climate debate.
They got 3,146 responses.
THIRD, to calculate his supposed “consensus” Prof. Doran excluded all but the most biased respondents: the most specialized specialists in climate science.
That’s a massive, fundamental blunder.
It’s like asking only homeopaths about the efficacy of homeopathy, rather than the broader medical community.
It’s like asking only people working on cold fusion about whether cold fusion works, rather than asking all physicists.
It makes the result completely meaningless. No matter how sketchy the practices in a field, if you ask only practitioners of that specialty you’ll always get strong agreement. Even if you asked astrologers whether astrology works, most would say “yes.”
By screening out all but the most specialized specialists in climatology, Doran excluded over 97% of the geophysical scientists who had answered the survey! Only 79 were left.
That’s right: he pruned 3,146 responses down to just 79.
But even that didn’t get his desired “consensus” figure up to 97%. So,
FOURTH, to calculate his final “97.4%” result, Doran excluded respondents who gave one of the “skeptical” answers to the first of his two questions.
I’m not kidding, he really did.
The first “gimme” question was:
“When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?”
(I would have said “risen” — after all, the 1700s were the Little Ice Age!)
Those who answered “remained relatively constant” were not asked the 2nd question, and they were not counted when calculating his percentage consensus.
That left Doran with just 77 out of 3,146 responses. He used only those 77 for the “97.4%” calculation.
The second question was:
“Do you think human activity is a significant contributing factor in changing mean global temperatures?”
Well, of course it is! That encompasses both GHG-driven warming and particulate/aerosol-driven cooling. It could also be understood to include Urban Heat Island (UHI) effects.
Since just about everyone acknowledges at least one of those effects, I would have expected nearly everyone to answer “yes” to this question. Yet 2 of 77 apparently did not.
It is unfortunate that Doran and his graduate student didn’t ask an actual, legitimate 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 President Obama) “Do you believe that climate change is real, man-made and dangerous?”
Of course the reason Prof. Doran didn’t ask “real” questions like those is that his survey was a scam: Its purpose was NOT to discover anything, it was to support a propaganda talking point.
You can find much more information about the various surveys of scientific opinion on climate change, including source references for everything I’ve written here, on this web page:
http://tinyurl.com/Clim97pct
