From: “Michael E. Mann” mann@virginia.edu
To: Malcolm Hughes mhughes@ltrr.arizona.edu , Tim Osborn t.osborn@uea.ac.uk , Keith Briffa k.briffa@uea.ac.uk , Kevin Trenberth trenbert@cgd.ucar.edu , Caspar Ammann ammann@ucar.edu , rbradley@geo.umass.edu, tcrowley@duke.edu, omichael@princeton.edu, jto@u.arizona.edu, Scott Rutherford srutherford@rwu.edu , p.jones@uea.ac.uk, mann@virginia.edu, Tom Wigley wigley@ucar.edu
Subject: Fwd: Correspondence on Harvard Crimson coverage of Soon / Baliunas views on climate
Date: Thu, 16 Oct 2003 16:43:41 -0400
Dear All,
Thought you would be interested in this exchange, which John Holdren of Harvard has been
kind enough to pass along...
mike
Delivered-To: mem6u@virginia.edu
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Date: Thu, 16 Oct 2003 13:53:08 -0400
To: “Michael Mann” mem6u@virginia.edu , “Tom Wigley” wigley@ucar.edu
From: “John P. Holdren” john_holdren@harvard.edu
Subject: Correspondence on Harvard Crimson coverage of Soon / Baliunas
views on climate
Michael and Tom —
I’m forwarding for your entertainment an exchange that followed from my being quoted in
the Harvard Crimson to the effect that you and your colleagues are right and my
“Harvard” colleagues Soon and Baliunas are wrong about what the evidence shows
concerning surface temperatures over the past millennium. The cover note to faculty
and postdocs in a regular Wednesday breakfast discussion group on environmental science
and public policy in Harvard’s Department of Earth and Planetary Sciences is more or
less self-explanatory.
Best regards,
John
Date: Thu, 16 Oct 2003 11:02:24 -0400
To: schrag@eps.harvard.edu, oconnell@eps.harvard.edu, holland@eps.harvard.edu,
pearson@eps.harvard.edu, eli@eps.harvard.edu, ingalls@eps.harvard.edu,
mlm@eps.harvard.edu, avan@fas.harvard.edu, moyer@huarp.harvard.edu,
poussart@fas.harvard.edu, jshaman@fas.harvard.edu, sivan@fas.harvard.edu,
bec@io.harvard.edu, saleska@fas.harvard.edu
From: “John P. Holdren” john_holdren@harvard.edu
Subject: For the EPS Wednesday breakfast group: Correspondence on Harvard Crimson
coverage of Soon / Baliunas views on climate
Cc: jeremy_bloxham@harvard.edu, william_clark@harvard.edu,
patricia_mclaughlin@harvard.edu,
Bcc:
Colleagues—
I append here an e-mail correspondence I have engaged in over the past few days trying
to educate a Soon/Baliunas supporter who originally wrote to me asking how I could think
that Soon and Baliunas are wrong and Mann et al. are right (a view attributed to me,
correctly, in the Harvard Crimson). This individual apparently runs a web site on which
he had been touting the Soon/Baliunas position.
While it is sometimes a mistake to get into these exchanges (because one’s interlocutor
turns out to be ineducable and/or just looking for a quote to reproduce out of context
in an attempt to embarrass you), there was something about this guy’s formulations that
made me think, at each round, that it might be worth responding. In the end, a couple
of colleagues with whom I have shared this exchange already have suggested that its
content would be of interest to others, and so I am sending it to our “environmental
science and policy breakfast” list for your entertainment and, possibly, future
breakfast discussion.
The items in the correspondence are arranged below in chronological order, so that it
can be read straight through, top to bottom.
Best,
John
At 09:43 PM 9/12/2003 -0400, you wrote:
Dr. Holdren:
In a recent Crimson story on the work of Soon and Baliunas, who have written for my
website [1]www.techcentralstation.com, you are quoted as saying:
My impression is that the critics are right. It s unfortunate that so much attention is
paid to a flawed analysis, but that s what happens when something happens to support the
political climate in Washington.
Do you feel the same way about the work of Mann et. al.? If not why not?
Best,
Nick
Nick Schulz
Editor
TCS
1-800-619-5258
From: John P. Holdren [[2]mailto:john_holdren@harvard.edu]
Sent: Monday, October 13, 2003 11:06 AM
To: Nick Schulz
Subject: Harvard Crimson coverage of Soon / Baliunas controversy
Dear Nick Schultz —
I am sorry for the long delay in this response to your note of September 12. I have
been swamped with other commitments.
As you no doubt have anticipated, I do not put Mann et al. in the same category with
Soon and Baliunas.
If you seriously want to know “Why not?”, here are three ways one might arrive at what I
regard as the right conclusion:
(1) For those with the background and patience to penetrate the scientific arguments,
the conclusion that Mann et al. are right and Soon and Baliunas are wrong follows from
reading carefully the relevant Soon / Baliunas paper and the Mann et al. response to it:
W. Soon and S. Baliunas, “Proxy climatic and environmental changes of the past 1000
years”, Climate Research, vol. 23, pp 89ff, 2003.
M. Mann, C. Amman, R. Bradley, K. Briffa, P. Jones, T. Osborn, T. Crowley, M. Hughes, M.
Oppenheimer, J. Overpeck, S. Rutherford, K. Trenberth, and T. Wigley, “On past
temperatures and anomalous late-20th century warmth”, EOS, vol 84, no. 27, pp 256ff, 8
July 2003.
This is the approach I took. Soon and Baliunas are demolished in this comparison.
(2) Those lacking the background and/or patience to penetrate the two papers, and
seriously wanting to know who is more likely to be right, have the option of asking
somebody who does possess these characteristics — preferably somebody outside the
handful of ideologically committed and/or oil-industry-linked professional
climate-change skeptics — to evaluate the controversy for them. Better yet, one could
poll a number of such people. They can easily be found by checking the web pages of
earth sciences, atmospheric sciences, and environmental sciences departments at any
number of major universities.
(3) The least satisfactory approach, for those not qualified for (1) and lacking the
time or initiative for (2), would be to learn what one can about the qualifications
(including publications records) and reputations, in the field in question, of the
authors on the two sides. Doing this would reveal that Soon and Baliunas are,
essentially, amateurs in the interpretation of historical and paleoclimatological
records of climate change, while the Mann et al. authors include several of the most
published and most distinguished people in the world in this field. Such an
investigation would also reveal that Dr. Baliunas’ reputation in this field suffered
considerable damage a few years back, when she put her name on an incompetent critique
of mainstream climate science that was never published anywhere respectable but was
circulated by the tens of thousands, in a format mimicking that of a reprint from the
Proceedings of the National Academy of Sciences, in pursuit of signatures on a petition
claiming that the mainstream findings were wrong.
Of course, the third approach is the least satisfactory because it can be dangerous to
assume that the more distinguished people are always right. Occasionally, it turns out
that the opposite is true. That is one of several good reasons that it pays to try to
penetrate the arguments, if one can, or to poll others who have tried to do so. But in
cases where one is not able or willing to do either of these things — and where one is
able to discover that the imbalance of experience and reputation on the two sides of the
issue is as lopsided as here — one ought at least to recognize that the odds strongly
favor the proposition that the more experienced and reputable people are right. If one
were a policy maker, to bet the public welfare on the long odds of the opposite being
true would be foolhardy.
Sincerely,
John Holdren
PS: I have provided this response to your query as a personal communication, not as
fodder for selective excerpting on your web site or elsewhere. If you do decide that
you would like to propagate my views on this matter more widely, I ask that you convey
my response in its entirety.
At 11:16 AM 10/13/2003 -0400, you wrote:
I have the patience but, by your definition certainly, not the background, so I suppose
it s not surprising I came to a different conclusion. I guess my problem concerns what
lawyers call the burden of proof. The burden weighs heavily much more heavily, given
the claims on Mann et.al. than it does on Soon/Baliunas. Would you agree?
Falsifiability for the claims of Mann et. al. requires but a few examples, does it
not? Soon/Baliunas make claims that have no such burden. Isn t that correct?
Best,
Nick
From: John P. Holdren [[3]mailto:john_holdren@harvard.edu]
Sent: Tuesday, October 14, 2003 5:54 PM
To: Nick Schulz
Subject: RE: Harvard Crimson coverage of Soon / Baliunas controversy
Nick—
Yes, I can see how it might seem that, in principle, those who are arguing for a strong
and sweeping proposition (such as that “the current period is the warmest in the last
1000 years”) must meet a heavy burden of proof, and that, because even one convincing
counter-example shoots the proposition down, the burden that must be borne by the
critics is somehow lighter. But, in practice, burden of proof is an evolving thing —
it evolves as the amount of evidence relevant to a particular proposition grows.
To choose an extreme example, consider the first and second laws of thermodynamics.
Both of these are “empirical” laws. Our confidence in them is based entirely on
observation; neither one can be “proven” from more fundamental laws. Both are very
sweeping. The first law says that energy is conserved in all physical processes. The
second law says that entropy increases in all physical processes. So, is the burden of
proof heavier on somebody who asserts that these laws are correct, or on somebody who
claims to have found an exception to one or both of them? Clearly, in this case, the
burden is heavier on somebody who asserts an exception. This is in part because the
two laws have survived every such challenge in the past. No exception to either has
ever been documented. Every alleged exception has turned out to be traceable to a
mistake of some kind. This burden on those claiming to have found an exception is so
strong that the US Patent Office takes the position, which has been upheld in court,
that any patent application for an invention that violates either law can be rejected
summarily, without any further analysis of the details.
Of course, I am not asserting that the claim we are now in the warmest period in a
millennium is in the same league with the laws of thermodynamics. I used the latter
only to illustrate the key point that where the burden is heaviest depends on the state
of prior evidence and analysis on the point in question — not simply on whether a
proposition is sweeping or narrow.
In the case actually at hand, Mann et al. are careful in the nature of their claim.
They write along the lines of “A number of reconstructions of large-scale temperature
changes support the conclusion” that the current period is the warmest in the last
millennium. And they write that the claims of Baliunas et al. are “inconsistent with
the preponderance of scientific evidence”. They are not saying that no shred of
evidence to the contrary has ever been produced, but rather that analysis of the
available evidence as a whole tends to support their conclusion.
This is often the case in science. That is, there are often “outlier” data points or
apparent contradictions that are not yet adequately explained, but still are not given
much weight by most of the scientists working on a particular issue if a strong
preponderance of evidence points the other way. This is because the scientists judge it
to be more probable that the outlier data point or apparent contradiction will
ultimately turn out to be explainable as a mistake, or otherwise explainable in a way
that is consistent with the preponderance of evidence, than that it will turn out that
the preponderance of evidence is wrong or is being misinterpreted. Indeed, apparent
contradictions with a preponderance of evidence are FAR more often due to measurement
error or analysis error than to real contradiction with what the preponderance
indicates.
A key point, then, is that somebody with a PhD claiming to have identified a
counterexample does not establish that those offering a general proposition have failed
in their burden of proof. The counterexample itself must pass muster as both valid in
itself and sufficient, in the generality of its implications, to invalidate the
proposition.
In the case at hand, it is not even a matter of an “outlier” point or other seeming
contradiction that has not yet been explained. Mann et al. have explained in detail why
the supposed contrary evidence offered by Baliunas et al. does NOT constitute a
counterexample. To those with some knowledge and experience in studies of this kind,
the refutation by Mann et al is completely convincing.
Sincerely,
John Holdren
At 08:08 AM 10/15/2003 -0400, you wrote:
Dr. Holdren:
Thank you for your thoughtful reply. I genuinely appreciate you taking the time.
You are quite right about the laws of thermodynamics. And you are quite right that Mann
et al is not in the same league as those laws and that s not to take anything from their
basic research.
You write to those with knowledge and experience in studies of this kind, the refutation
by Mann et all is completely convincing. Since I do not have what you would consider
the requisite knowledge or experience, I can t speak to that. I ve read the Mann papers
and the Baliunas Soon paper and the Mann rebuttal and find Mann s claims based on his
research extravagant and beyond what he can legitimately claim to know. That said, I m
willing to believe it is because I don t have the tools necessary to understand.
But if you will indulge a lay person with some knowledge of the matter, perhaps you
could clear up a thing or two.
Part of the confusion over Mann et al it seems to me has to do not with the research
itself but with the extravagance of the claims they make based on their research.
And yet you write: Mann et al. are careful in the nature of their claim. They write
along the lines of A number of reconstructions of large-scale temperature changes
support the conclusion that the current period is the warmest in the last millennium.
And they write that the claims of Baliunas et al. are inconsistent with the
preponderance of scientific evidence .
That makes it seem as if Mann s not claiming anything particularly extraordinary based
on his research.
But Mann claimed in the NYTimes in 1998 that in their Nature study from that year Our
conclusion was that the warming of the past few decades appears to be closely tied to
emission of greenhouse gases by humans and not any of the natural factors.” Does that
seem to be careful in the nature of a claim? Respected scientists like Tom Quigley
responded at the time by saying “I think there’s a limit to how far you can ever go.” As
for using proxy data to detect a man-made greenhouse effect, he said, “I don’t think
we’re ever going to get to the point where we’re going to be totally convincing.” These
are two scientists who would agree on the preponderance of evidence and yet they make
different claims about what that preponderance means. There are lots of respected
climatologists who would say Mann has insufficient scientific basis to make that claim.
Would you agree? The Soon Baliunas research is relevant to that element of the debate
what the preponderance of evidence enables us to claim within reason. To that end, I
don t think claims of Soon Baliunas are inconsistent with the preponderance of
scientific evidence.
I ll close by saying I m willing to admit that, as someone lacking a PhD, I could be
punching above my weight. But I will ask you a different but related question How much
hope is there for reaching reasonable public policy decisions that affect the lives of
millions if the science upon which those decisions must be made is said to be by
definition beyond the reach of those people?
All best,
Nick
Date: Thu, 16 Oct 2003 08:46:23 -0400
To: “Nick Schulz” nschulz@techcentralstation.com
From: “John P. Holdren” john_holdren@harvard.edu
Subject: RE: Harvard Crimson coverage of Soon / Baliunas controversy
Nick—
You ask good questions. I believe the thoughtfulness of your questions and the progress
I believe we are making in this interchange contain the seeds of the answer to your
final question, which, if I may paraphrase just a bit, is whether there’s any hope of
reaching reasonable public-policy decisions when the details of the science germane to
those decisions are impenetrable to most citizens.
This is a hard problem. Certainly the difficulty is not restricted to climate science
and policy, but applies also to nuclear-weapon science and policy, nuclear-energy
science and policy, genetic science and policy, and much more. But I don’t think the
difficulties are insurmountable. That’s why I’m in the business I’m in, which is
teaching about and working on the intersection of science and technology with policy.
Most citizens cannot penetrate the details of what is known about the how the climate
works (and, of course, what is known even by the most knowledgeable climate scientists
about this is not everything one would like to know, and is subject to modification by
new data, new insights, new forms of analysis). Neither would most citizens be able to
understand how a hydrogen bomb works (even if the details were not secret), or what
factors will determine the leak rates of radioactive nuclides from radioactive-waste
repositories, or what stem-cell research does and promises to be able to do.
But, as Amory Lovins once said in addressing the question of whether the public deserved
and could play a meaningful role in debates about nuclear-weapon policy, even though
most citizens would never understand the details of how nuclear weapons work or are
made, “You don’t have to be a chicken to know what to do with an egg.” In other words,
for many (but not all) policy purposes, the details that are impenetrable do not matter.
There CAN be aspects of the details that do matter for public policy, of course. In
those cases, it is the function and the responsibility of scientists who work across the
science-and-policy boundary to communicate the policy implications of these details in
ways that citizens and policy makers can understand. And I believe it is the function
and responsibility of citizens and policy makers to develop, with the help of scientists
and technologists, a sufficient appreciation of how to reach judgments about
plausibility and credibility of communications about the science and technology relevant
to policy choices so that the citizens and policy makers are NOT disenfranchised in
policy decisions where science and technology are germane.
How this is best to be done is a more complicated subject than I am prepared to try to
explicate fully here. (Alas, I have already spent more time on this interchange than I
could really afford from other current commitments.) Suffice it to say, for now, that
improving the situation involves increasing at least somewhat, over time, the scientific
literacy of our citizens, including especially in relation to how science works, how to
distinguish an extravagant from a reasonable claim, how to think about probabilities of
who is wrong and who is right in a given scientific dispute (including the question of
burden of proof as you and I have been discussing it here), how consulting and polling
experts can illuminate issues even for those who don’t understand everything that the
experts say, and why bodies like the National Academy of Sciences and the
Intergovernmental Panel on Climate Change deserve more credibility on the question of
where mainstream scientific opinion lies than the National Petroleum Council, the Sierra
Club, or the editorial page of the Wall Street Journal.
Regarding extravagant claims, you continue to argue that Mann et al. have been guilty of
this, but the formulation of theirs that you offer as evidence is not evidence of this
at all. You quote them from the NYT in 1998, referring to a study Mann and co-authors
published in that year, as saying
“Our conclusion was that the warming of the past few decades appears to be closely
tied to emission of greenhouse gases by humans and not any of the natural factors.”
and you ask “Does that seem to be careful in the nature of a claim?” My answer is:
Yes, absolutely, their formulation is careful and appropriate. Please note that they
did NOT say “Global warming is closely tied to emission of greenhouse gases by humans
and not any of the natural factors.” They said that THEIR CONCLUSION (from a
particular, specified study, published in NATURE) was that the warming of THE PAST FEW
DECADES (that is, a particular, specified part of the historical record) APPEARS (from
the evidence adduced in the specified study) to be closely tied... This is a carefully
specified, multiply bounded statement, which accurately reflects what they looked at and
what they found. And it is appropriately contingent —”APPEARS to be closely tied” —
allowing for the possibility that further analysis or new data could later lead to a
different perspective on what appears to be true.
With respect, it does not require a PhD in science to notice the appropriate boundedness
and contingency in the Mann et al. formulation. It only requires an open mind, a
careful reading, and a degree of understanding of the character of scientific claims and
the wording appropriate to convey them that is accessible to any thoughtful citizen.
That is why I’m an optimist.
You go on to quote the respected scientist “Tom Quigley” as holding a contrary view to
that expressed by Mann. But please note that: (1) I don’t know of any Tom Quigley
working in this field, so I suspect you mean to refer to the prominent climatologist Tom
Wigley; (2) the statements you attribute to “Quiqley” do not directly contradict the
careful statement of Mann (that is, it is entirely consistent for Mann to say that his
study found that recent warming appears to be tied to human emissions and for Wigley to
say that that there are limits to how far one can go with this sort of analysis, without
either one being wrong); and (3) Tom Wigley is one of the CO-AUTHORS of the resounding
Mann et al. refutation of Soon and Baliunas (see attached PDF file).
I hope you have found my responses to be of some value. I now must get on with other
things.
Best,
John Holdren
JOHN P. HOLDREN
JOHN P. HOLDREN
______________________________________________________________
Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
_______________________________________________________________________
e-mail: mann@virginia.edu Phone: (434) 924-7770 FAX: (434) 982-2137
[4]http://www.evsc.virginia.edu/faculty/people/mann.shtml
References
1. http://www.techcentralstation.com/
2. mailto:john_holdren@harvard.edu
3. mailto:john_holdren@harvard.edu
4. http://www.evsc.virginia.edu/faculty/people/mann.shtml
Notice the Teresa Heinz and the Kennedy part.
Heinz (before his death) was GOP, IIRC, but Teresa is not. She married Sen. Gigolo Purple Heart (who by the way served in Viet Nam, and who to my knowledge never released his original full SF 180).
Cheers!