David Burton <redacted>

Doran/Zimmerman "97%" miscalculated, please correct SkepticalScience article

David Burton <redacted> Thu, Aug 13, 2020 at 3:55 PM
To: "John Cook, SkepticalScience webmaster" <redacted>
Cc: Ari Jokimäki <redacted>, "Dr. Gavin Cawley" <redacted>, Bärbel Winkler <redacted>, Dana Nuccitelli <redacted>, James Wight <redacted>, "Neal J. King" <redacted>, Doug Bostrom <redacted>, Daniel Bailey <redacted>
Dear John,

I see you have signed on with the Pro-Truth Pledge project, on behalf of your SkepticalScience web site. Does that mean you will finally correct the misinformation on your site about Doran & Zimmerman 2009?

This page https://www.skepticalscience.com/debunking-climate-consensus-denial.html says, "Doran & Zimmerman (2009) found a 97% consensus among scientists actively publishing climate research."

That statement is untrue. The correct figure they found was "less than 90%".

Doran's EOS article (apparently not peer-reviewed, BTW) claimed that 90% (not 97%) of scientists actively publishing climate research agree on these two points:


Here's the graphic from Doran's EOS article (I added the pink annotation):

For active publishers on climate science, Doran reported only 90% agreement, and even that was exaggerated.

Doran's "97%" claim was not for "scientists actively publishing climate research," it was for only the 79 (out of 3,146) most specialized specialists ("climatologists").

What's more, even that claim was incorrect. Only 75 of the 79 most specialized specialists, actively publishing climatologists, actually agreed on those two points of "consensus." That's 94.9%, not 97%.

Doran miscalculated. He identified 79 specialists in climatology who were active publishers, four of whom disagreed on at least one of the two points of "consensus." But to calculate his "97%" he first discarded two of the four dissenters.

It told you about that error in 2013, 2014 & 2015. You didn't bother to correct the misinformation on your site then. Will you please do so now?

It is virtually certain that Doran made the same error when calculating his 90% claim, for the level of agreement among scientists actively publishing climate research. However, I've been unable to find the data which would enable me to calculate the actual percentage. Prof. Doran was hostile and uncooperative, his former graduate student doesn't have his data, and the University of Illinois responded to my FOIA request by saying that the data was not in their possession.

So all we can say with certainty is that the consensus was less than 90%, but (based on what Doran revealed about the overall responses to the two questions) it was probably at most about 85%.

Will you please honor your Pro Truth Pledge, and correct the misinformation on your site about Doran & Zimmerman 2009?

(BTW, I am part of the ≈85% consensus. I agree with the "consensus," on both points. The best evidence is that globally averaged temperatures have risen since the LIA, and mankind contributed to that rise. However, the best evidence also shows that anthropogenic warming is modest and benign, and CO2 emissions are beneficial, rather than harmful.)

Sincerely,

Dave Burton
www.sealevel.info
M: +1 919-244-3316


On Thu, Jul 23, 2015 at 2:48 PM David Burton <redacted> wrote:
Dear Mr. Cook,

Are you receiving my emails?

Dave


On Mon, Feb 2, 2015 at 2:04 PM, David Burton <redacted> wrote:
Mr. Cook, are you receiving my emails?

Dave


On Wed, Jul 9, 2014 at 12:46 PM, David Burton <redacted> wrote:
Mr. Cook, did you receive my email?

Dave


On Mon, Dec 16, 2013 at 3:57 PM David Burton <redacted> wrote:
Dear Mr. Cook,

Did you receive my email, below?

To reach their "97%" conclusion, Doran & Zimmerman (2009) counted only half of the dissenters among the 79 respondents who they called "the most specialized and knowledgeable."

Never mind the other flaws in their methodology, that was a plain, indisputable error. If they hadn't failed to count 50% of the dissenters, the result would have been 94.9%, not 97.4%.

On your site you say that "Doran & Zimmerman (2009) found a 97% consensus among scientists actively publishing climate research." Will you please correct your web page, to reflect the fact that Doran & Zimmerman miscalculated?

Note: I've cc'd this to a couple of your colleagues who probably have relevant expertise.

Warmest regards,
Dave

 
On Wed, Dec 11, 2013 at 11:01 AM, David Burton <redacted> wrote:
Dear Mr. Cook,

On your web site you wrote that "Doran & Zimmerman (2009) found a 97% consensus among scientists actively publishing climate research." But did you know that Doran & Zimmerman miscalculated their result?

To maximize their "consensus" number, Zimmerman & Doran:

1. Chose to survey only scientists at academic and government institutions (which generally lean Left), and

2. Asked "no-brainer" questions that almost everyone, even climate skeptics, would answer "correctly,"  and

3. Did not ask any questions that would actually separate alarmists from skeptics, such as whether, in President Obama's words, "climate change is real, man-made and dangerous," and

4. Used only 79 out of the 3146 responses that they received, when calculating their degree-of-agreement percentage. They called those 79 "the most specialized and knowledgeable respondents (with regard to climate change)."

They reported that 75 of the "most specialized and knowledgeable respondents" agreed with the "consensus" position that "mean global temperatures have generally risen" since the depths of the Little Ice Age and "human activity is a significant contributing factor in changing mean global temperatures."

Note #1: by that measure, even I am part of the consensus.

Note #2: They concluded that, "It seems that the debate on the authenticity of global warming and the role played by human activity is largely nonexistent among those who understand the nuances and scientific basis of long-term climate processes."

Note #3: Their methodology could easily be used to reach the conclusion that "the debate on the authenticity of acupuncture is largely nonexistent among those who understand its nuances and scientific basis."

Yet all that was insufficient.  75 of 79 is not 97%, it is only 94.9%.

So how did they get to 97%?

The answer is that they simply didn't count the two "most specialized and knowledgeable respondents" who had said they thought global temperatures "remained relatively constant."
79 - 2 = 77, and 75 / 77 = 97.4% = mission accomplished.

That's right, it's hard to believe, but they simply didn't count two of the four dissenters among the 79 who they identified as the "most specialized and knowledgeable respondents."

On that basis they reported in the prestigious journal Eos, Transactions, American Geophysical Union, that:

[of] "the most specialized and knowledgeable respondents (with regard to climate change)... 97.4% (75 of 77) answered yes to question 2. [Q2: Do you think human activity is a significant contributing factor in changing mean global temperatures?]"

I've written this up in more detail, here.

Will you please correct your web page, to reflect the fact that Doran & Zimmerman miscalculated?

Warmest regards,

Dave Burton
Cary, NC