David Burton writes:
I just realized the obvious answer to a question that has been nagging in the back of my mind for nearly a year and a half.
In 2008 Margaret Zimmerman asked two questions of 10,257 Earth Scientists at academic and government institutions. 3146 of them responded. That survey was the original basis for the famous “97% consensus” claim.
For the calculation of the degree of consensus among experts in the Doran/Zimmerman article, all but 79 of the respondents were excluded. They wrote:
“In our survey, the most specialized and knowledgeable respondents (with regard to climate change) are those who listed climate science as their area of expertise and who also have published more than 50% of their recent peer-reviewed papers on the subject of climate change (79 individuals in total). Of these specialists, 96.2% (76 of 79) answered “risen” to question 1 and 97.4% (75 of 77) answered yes to question 2.”
The basis for the “97% consensus” claim is this excerpt:
[of] “the most specialized and knowledgeable respondents (with regard to climate change)… 97.4% (75 of 77) answered yes to question 2.”
But that is a false statement.
The two questions were:
Q1: “When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?” 76 of 79 (96.2%) answered “risen.”
Q2: “Do you think human activity is a significant contributing factor in changing mean global temperatures?” 75 of 77 (97.4%) answered “yes.”
My nagging question was, why did different numbers of people (79 vs. 77) answer the two questions? What happened to the other two respondents?
The answer to that question is not in the Doran article.
But it is in the Zimmerman report, a copy of which I bought back in March, 2012. The reason I feel stupid is that I read it and even quoted the relevant part way back then, and it still took me until now to realize the obvious answer to my nagging question.
This was the full set of questions that Zimmerman asked in their survey:
Q1. When compared with pre-1800's levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?1. Risen2. Fallen3. Remained relatively constant4. No opinion/Don't knowQ2. Do you think human activity is a significant contributing factor in changing mean global temperatures? [This question wasn’t asked if they answered “remained relatively constant” to Q1]1. Yes2. No3. I'm not sureQ3. What do you consider to be the most compelling argument that supports your previous answer (or, for those who were unsure, why were they unsure)? [This question wasn’t asked if they answered “remained relatively constant” to Q1]Q4. Please estimate the percentage of your fellow geoscientists who think human activity is a contributing factor to global climate change.Q5. Which percentage of your papers published in peer-reviewed journals in the last 5 years have been on the subject of climate change?Q6. AgeQ7. GenderQ8. What is the highest level of education you have attained?Q9. Which category best describes your area of expertise?
Do you see it? If a respondent answered “remained relatively constant” to the first question, then he wasn’t asked the second question!
That’s obviously why only 77 answers were reported to the second question. Two of their 79 top climate specialists had answered “remained relatively constant” to the first question, and those two were not asked the second question, and were not included in the calculation of the supposed 97.4% agreement.
That means only 75 of 79 (94.9%) of their “most specialized and knowledgeable respondents” actually gave them the answers they wanted to both of their questions.
So, despite asking “dumb questions” that even most skeptics would answer “correctly,” and despite excluding over 97% of the responses after they were received, they still did not find 97% agreement. They actually found only 94.9% agreement.
I’ve updated my http://tinyurl.com/Clim97pct page to reflect that fact.
I’ve also emailed the editor of Eos, which published their article back in 2009, asking that they run a correction.
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“Humans have had a “significant impact” on warming is pretty vague.
Also, why does anyone care what a survey conducted in 2008 show?
A lot of water under the bridge since then.
I personally made the Sun rise this morning. And this had never happened before.
Lies, damn lies and statistics.
Given the results of the Surface Station project, and the frequent and ill-advised manipulation of historical and current temperature data, I’d say that warming definitely has a strong human component, just not in the way they think.
How they arrived at it is merely an exercise in Marketing. That it is a worthless number that has no meaning is what is scientifically valid.
Is the underlying data of ALL responses actually available? So, of the 3000+ responses, how did the data break down?
@Harold Ambler says:
…I personally made the Sun rise this morning. And this had never happened before…
Quite right. Yesterday, it was me…
Also, the answer to the second question would include people that thought temperature was lower and that it was caused by humans. It doesn’t seem likely that any would answer this, but there’s nothing in the question or data *as* *reported* above.
“I’ve also emailed the editor of Eos, which published their article back in 2009, asking that they run a correction.”
Why waste time doing that?
To any audience says 95% of scientists …. blah, blah, is just the same as saying 97%.
You asking them to correct it , implies that you would consider it better if it showed the “correct” number of 95% , when in fact the whole thing is BS, game playing that should be retracted in its entirety.
The unpublished question number 0 was probably the most important one:
Q0 Would you like more money and public funds to be directed to you area of research in the future?
Those who replied “No” or “Don’t care” were obviously not to be considered experts in relevant fields of study. and were not asked the rest of the questions.
“I’ve also emailed the editor of Eos, which published their article back in 2009, asking that they run a correction.”
Why waste time doing that?
To any audience says 95% of scientists …. blah, blah, is just the same as saying 97%.
Quite a scientific study. Science by consensus, I’m impressed.
That really feels like a cherry picked bunch of yes men, with a couple of dissenters just for effect to make it feel like a proper survey.
What happened to the other two , what happened to the other three thousand plus.
I’ve always been appalled that a Masters degree was awarded for this torturing of data.
The 97% is still being quoted in the MSM, it would be good to get it changes, pointing out the mistake, now that the lame questions and methods are out in the open.
A more thorough revisit with publicity could be worthwhile.
EthicallyCivil says:
December 10, 2013 at 8:14 am
“Also, the answer to the second question would include people that thought temperature was lower and that it was caused by humans. It doesn’t seem likely that any would answer this, but there’s nothing in the question or data *as* *reported* above.”
During the cooling 70ies and up to 1988 the scare scientists postulated that an increase of CO2 due to human activity was the cause of the cooling; arguing that CO2, being IR-active, was emitting more energy to space; leading to an “ice age”, as the media reported (the journalists meant to say “glaciation”, but were too stupid for that).
The scare scientists switched to warming over time, as a glaciation became impossible to market, arguing CO2 emitted more IR to the surface; the switch was complete in 1988, when Hansen performed his infamous A/C stunt. The scare scientists remained the same; each one making his choice between being efficient, and being honest, as Schneider demanded.
Why did they ask Q2 and Q3 if the answer to Q1 was: “4. No opinion/Don’t know”?
The first question was trivial. 1800 was in the midst of the Little Ice Age, so OF COURSE it’s warmer now.
The second question is also trivial if you keep in mind that, as used by the UN and the IPCC, “Climate Change” is BY DEFINITION anthropogenic. It’s hardly surprising that anybody who publishes papers on “Climate Change” believes it is anthropogenic, or they would have used different terminology.
Harold Ambler and Dodgy Geezer go on about how they made the sun rise.
Will you knuckleheads please knock it off? Do you have any idea how hard I work to make the Sun set?!
“Q2. Do you think human activity is a significant contributing factor in changing mean global temperatures?”
This says nothing of ‘warming’. Land use may have very well kept the temperatures more moderate duing the LIA recovery, keeping it slightly lower than it would have been keeping all else kept constant. This question is ambiguous and fails the survey. Also, few think humans have directly affected ocean temperatures so this would imply global land-only temperature records, again ambiguous.
It’s not just that being warmer than during the Little Ice Age is trivially true, but the use of the term ‘significant’ is ambiguous.
Most lay people use ‘significant’ to mean ‘major, important, big, predominant’ or other such, whereas those accustomed to dealing with measurement and the statistics thereof use ‘significant’ as meaning simply ‘detectable above the noise’.
So I, for example, would have to say yes to both questions, even though I’m not a believer in catastrophic AGW.
I want to know how many of them predicted the coldest temperature ever measured.
Thanks for this post David B. I hadn’t seen the full questions yet, and neither was I aware of the exact phrasing om Q2:
The obvious follow-up question, in my opinion, would be:
What exaclty is meant by “a significant contributing factor”? And how would this be quantified? To me thos looks like a advertently vague ambiguous question, that could easily be misintepreted by a casual reader or a referring churnolist.
Humm, 3,146 responses reduced to 77 in the final segment on human caused global warming. Evidently, this filtering process ended up in the innards of the Health Exchange website insurance application process generating the same 77 completed applications on the first day. You doubt this possibility? Prove it as wrong, go ahead.
Why it is important to bring this up again is that not only MSM still quote it, but Obama has used the 97% argument again recently.
75 scientists say the science is settled!