Climategate reloaded/MWP

Die neuen Mails enthalten viele Aussagen zur MWP und Wissenschaftern, welche sich positiv zur Begrifflichkeit und/oder deren Ausdehnung äußerten.

Broecker veröffentlichte 2001 in Science einen Artikel, in welchem er die Frage aufwarf, ob die MWP global gewesen ist - Was the Medieval Warm Period Global? Die Reaktionen blieben nicht aus (Hervorhebungen von mir). 

Email Nr. 0983196231

From: "Michael E. Mann" 
To: Phil Jones Subject: Re: Wally
Date: Mon, 26 Feb 2001 09:03:51 -0500
Cc: mhughes@[gel. W.v.B.], tom crowley ,  rbradley@[gel. W.v.B.], 
tom@[gel. W.v.B.], k.briffa@[gel. W.v.B.],  t.osborn@[gel. W.v.B.],
mann@[gel. W.v.B.]

Dear Phil,

Thanks for your response. I agree that I think these folks just don't quite
seem to get it! Anyways, I've pasted in the text of Broecker's piece below
(everything there but the figure. Trust me, the figure isn't worth looking
at anyways). Will be very interested to hear your thoughts after reading


Was the Medieval Warm Period Global?
[Broeckers Arbeit wird vollständig angeführt, gel. von mir]

At 12:04 PM 2/26/01 +0000, Phil Jones wrote: 
Dear All,
I was away over the weekend at Bowdoin College in Maine, giving a talk about the 
last 1000 years. There were three others as well on other paleo aspects, 
Richard Alley, Gary Clow and Wally Broecker !  The latter briefly mentioned to me 
that he had had something in last Friday's Science, which was getting at the Mann 
et al. series. He didn't have a copy so we've not seen it here yet. I tried to get 
a copy tof Science on the bookstand at Logan airport last night - I guess it's not
sold that way ! Wally was going on about this 1500 yr cycle of Bond's, which seemed 
pretty flimsy. I was showing all the various series in a general talk - and I used 
some  of the overheads from the upcoming Science paper. This is due to appear in 
the issue for the last week of April. It is all accepted now. I will forward if 
you'll all abide by the Science rules. Both Wally and Alley seem convinced that 
the climate of Greenland changed by 10 C in the space of 2-3 years at times in the 
past (Y Dryas etc).
I had long talks with both and they don't seem to have got their heads around 
spatial scales (local changes and hemispheric). Also they don't seem to realise 
where we are coming from. He has a downer on trees (believes all the multiproxy
series depend exclusively on trees) but he thinks Ed Cook is a great scientist.  
The latter is true, but he might just think that because he's at Lamont. I did 
tell him that Keith's paper on the age banding is out in JGR. I should send him a 
reprint and maybe ask that great scientist to go and explain it to him ! Ed's in 
NZ at the moment. Also Wally believes much more in glacier advances/retreats. 
I'll get Keith to send him Sarah's paper where the long Tornetrask reconstruction 
is shown to agree with Storglaciaren advance/retreat dates from moraine evidence. 
Also Sarah's been working on similar glaciers in the Swiss Alps with long tree-ring 
One interesting thing was he didn't seem to realise that a lot of the tree-ring 
reconstructions use density. Seemed to think they were all ring widths and there 
had to be moisture changes we were not accounting for. It is easy to respond to a 
Perspectives piece. Some of you did it with respect to one of mine. I'm not sure 
it will achieve much - it won't come out before the paper in the last week of April.
I need to wait to se what he says. Our paper (me, Tim and Keith) clearly says that 
the MWP couldn't have been warmer (for the NH average) than the late 20th century. 
Another possible reason for not doing anything is that the IPCC report will be out
soon. The summary is written in pretty clear language. The above is my first 
thoughts, not having read the piece and just got off the flight back.

Best to ignore Woijcek. All he seems to want to do is deflect us into 

At 11:47 25/02/01 -0700, mhughes@[gel. W.v.B.] wrote:
Dear all,
WHat mechanism does "Science" have for repsonding to Perspective pieces?
Most of the answer to Wally is contained within his own piece - he comments on
the ambiguity of the record, which, in various ways, we have all done. What he
doesn't offer, however, is anything other than an anecdotal alternative. As
always, he seeks to damn ( in this case with faint praise) the records or 
work that don't serve his purpose , and to elevate any scrap of evidence that
does serve it. I think it will be important for us to stick closely to what we 
have written in published papers. CHeers, MAlcolm

Quoting "Michael E. Mann":

Dear Phil, Ray,

What do you guys think. If we're all on board, than an appropriately
toned,"high road" response here might be appropriate. We don't want to engage
Wally in a personal battle, but simply should correct the record where
Wally has muddied it. Again, Phil et al do have a Science article in
press that serves this purpose to some extent, so I'm especially interested in
what Phil thinks (Phil?)...


At 02:52 PM 2/24/01 -0700, mhughes@[W.v.B.] wrote:
Dear Mike et al., I think we should definitely let Wojick stew in his
 own juice - as Mike pointed out to me the other day he, and his like, have
a specific agenda, and anything we write will be pressed into the service
of that agenda. I'm not so sure about Wally. I share Tom's disinclination to
get into a street fight with Wally - generally I take the view that life's too
short and uncertain for such activities. On the other hand, would we let such a
shoddy piece of work(and editing) go by if it were from another author? There
are so many holes in Wally's argument, and such a selective choice of evidence
that it should beggar belief. One of the more obvious holes is that he writes
of the Great Basin droughts of the 10th through 14th centuries as proof of
warmer conditions then, but doesn't explain why we don't have such conditions
now. Interestingly, Larry Benson, Dave Meko and others have good evidence
that these same multidecadal periods were marked by a great excess of precipitation
just a few hundred miles north in northern Nevada and California and southern
He just hasn't grasped that the methods that are appropriate for tracking the
consequences of major changes in boundary conditions don't work in the late
Holocene. I've been trying to figure out the issue of "Was there a Medieval
Warm Period, and if so where and when" for a decade or so, and still have the
impression that the records for the 9th through 14th centuries are extremely
mixed. But then, I didn't come to the investigation with a certain knowledge of
the absolute truth, and have had to 'misfortune' to work with people
who let careful analysis get in the way - Henry Diaz, Ray and Mike, and others.

Anyway, the point of this rant is that I think we should give careful
consideration to making a measured response to Wally. Cheers, Malcolm
Quoting "Michael E. Mann":

Hi Tom,

Thanks for your quick reply. I agree with you entirely. I think its very
unfortunate he's chosen to disinform the community rather than engage in
a constructive dialogue (we tried the latter w/ him in a series of emails
last year, but clearly to no avail).

On the other hand, think that a war of words w/ Broecker would be exploited
by the skeptics, and perhaps we should just try to let this thing die...

I'm not sure. I'd appreciate knowing what others think?

At 10:25 AM 2/24/01 -0600, tom crowley wrote:

I was not aware of the Broecker piece - I am dismayed but not surprised. I do not 
know what to do - I personally cannot stand the combative personal approach 
Broecker relishes but it does seem as if some rebuttal is called for. Maybe you 
Ray Phil I and Malcolm could pen a response - we are heading to Germany in a week, 
for a month, so I am not sure how much I can keep  up on this but it seems as if 
some response is called for.

What think ye?


Dear Mike,

Thanks for passing this along.

Wojick of course completely misrepresents Broecker, and puts his conventional 
intellectually dishonest spin on this. 
That having been said, it is a bit disappointing that Wally continues to cling to 
some of his flawed beliefs which aren't supported from either our best current 
understanding of the observations or of the results of careful modeling experiments. 
My own perception is that the climate community, modelers as well as observationalists, 
simply don't take seriously anymore the idea that the history of climate change 
over the past 1000 years is part of an internal oscillation. The sediment core 
evidence oft cited by Broecker (e.g. Bond et al) for this is tremendously weak, 
and I, as well as the vast majority of my colleagues, simply don't buy it for even 
a second. But people don't like to challenge Broecker publically. He can and will
play hardball.

There is an odd irony. Broecker refused to accept the modeling evidence
that the 100 kyr ice age Pleistocene variations were part of an internal
oscillation paced by insolation variations, favoring instead the discredited 
notion that they were a direct response to (too weak) eccentricity forcing, until 
the evidence became insurmountable (from my adviser, Barry Saltzman, may he rest 
in piece, and people like Dick Peltier). Ironically, Broecker then took credit for 
the very proposition he had fought w/ tooth and nail.

Broecker is even more wrong, and unfortunately equally stubborn, in this case.
And, again, the reason: because his pet theory, that climate variability is
a simple millennial oscillation, is finally being challenged w/hard data
and hard facts.

Broecker misrepresents the nature of that data that we and others have
used, and misunderstands the source of the muted hemispheric trends (there
*is* a hemispheric "medieval warm period" and "little ice age", just not of
the magnitude or the distinctiveness that Broecker imagines). Individual
regions in our reconstructions, and Phils, and others, vary by several
degrees C, ie, the proxies we use have no problem whatsoever in resolving
high-amplitude temperature variations in the past. The problem is that when
we look at  the different regions we find that periods of cold and warm
often occur at very different times in different regions, and so in a
hemispheric or global average, a lot of purely regional variability cancels
out. The resulting trends are somewhat smaller. I remained befuddled as to
why Wally doesn't understand this point. Its been explained to him
time and time again. Maybe he's just not listening, or doesn't want to listen...

In fact, Tom Crowley has clearly shown that the observed millennial temperature 
reconstruction is precisely consistent w/ our understanding of *forced* climate 
change over the past 1000 years (solar changes, volcancic output, and recent 
greenhouse gas concentrations). There is, simply put, no room for a global 
millennial internal oscillation. Regionally, such types of climate phenomena, 
associated for example with changes in the North Atlantic ocean circulation, are 
supported by the observations. This explains why, for example, European temperature 
variations are somewhat larger than those in other regions not effected so strongly 
by such climate processes.

Other recent perspectives, by Ray Bradley and myself provide a far more
balanced and nuanced (and less dogmatic or defensive) viewpoint. I'm not
sure a written response to Broecker is worthwhile (this is, afterall, a
"perspective" and everyone understands that a scientist may have a flawed
perspective). If Wally wants this to be his legacy, so be it...

Phil and others have a review article coming out in the near future which
also provides a much more balanced perspective on the climate changes of
the past millennium, and will set the record straight once again (good
timing Phil!). Science's embargo policy prevents me from saying much more
at this time, but if Phil or anyone else wishes to comment further, I'd encourage 
it. Well, I've still got some snow to shovel here in Charlottesville!
Happy weekend to all,


p.s. For those with electronic subscriptions, Broecker's latest piece can be found 

Was the Medieval Warm Period Global?
Wallace S. Broecker
Science Feb 23 2001: 1497-1499. [Summary] [Full Text]

While my previous perspective piece is here: CLIMATE CHANGE: Lessons for a New 
Michael E. Mann
Science 2000 July 14; 289: 253-254. (in Perspectives) [Summary]
[Full Text]

and Bradley's is here:

PALEOCLIMATE: Enhanced: 1000 Years of Climate Change
Ray Bradley Science 2000 May 26; 288: 1353-1355. (in Perspectives) [Summary]
[Full Text]


Dear Michael--The third point below has comments on the controversy
between you and Broecker--I'd be interested in your response (did Wally not
just understand what your data show?). Mike Mike

Three Wojick Pieces on Climate Change. I've been busy busy.


FIRST, the latest issue of Insight Magazine includes a point-counterpoint
between measly old me and the great Robert Watson. Boy has he got credentials! Too 
bad he's wrong. Symposium: Do scientists have compelling evidence of global warming?

Yes: Rising sea levels worldwide and retreating Arctic glaciers ominous signs.

By Robert T. Watson -- chairman of the UN Intergovernmental Panel on
Climate Change, chief scientist at the World Bank and former chief science advisor 
to the Clinton White House. No: Despite the overheated rhetoric, there is no new 
evidence of warming

By David E. Wojick -- covers climate policy for Electricity Daily and
is a science adviser to the Greening Earth Society as well as Undereditor of
the Washington Pest 

SECOND, the February 15 Eco-logic on-line has published "The Black Hole of
Global Climate Government" by David Wojick, my detailed attack on the
Framework Convention on Climate Change. It includes a lot of the actual treaty 

THIRD, here is a draft Electricity Daily article of mine. Seems I'm not the only 
one who thinks the IPCC is nuts.

Climate Guru Kicks The Hockey Stick
David Wojick (dwojick@[gel. W.v.B.)

Ich bin beruhigt, dass M. Mann der Meinung ist: there *is* a hemispheric "medieval warm period" and "little ice age", frage mich dann aber schon, warum er in seinen Publikationen immer von einer MCA spricht. Fraglich erscheint mir, dass eine wissenschaftliche Entgegnung im Kreis einer Gruppe, einer "Gang" angestrebt wird. Broecker hat eine andere wissenschaftliche Meinung, diese wird diskreditiert und versucht, gemeinsam

If we're all on board, than an appropriately toned, "high road" response here might be appropriate.

über die Autorität, dieser Meinung zu begegnen.

Email Nr. 0983286849

From: Phil Jones [gel. W.v.B.]
To: mann[gel. W.v.B.]
Subject: Fwd: RE: Science issue Feb 22/23
Date: Tue, 27 Feb 2001 10:14:09 +0000
Cc: mhughes@[gel. W.v.B.],rbradley@[gel. W.v.B.],tom@[gel. W.v.B.], 
k.briffa@[gel.W.v.B.].osborn@[gel. W.v.B.]

Mike et al,
Sorry about the multiple sendings. I've forgotten my glasses and 
couldn't see I'd missed a comma. Another thing to point to is the special issue of 
Climatic Change by Astrid Ogilbie and Trausti Jonsson.  They point to the LIA not 
being very appropriate in Iceland.


       So Julia handled it. Even she thought it was handwaving, but it passed the 
usual Science review process.  Obviously this isn't great as none of us got to 
review it. Odd that she didn't send it to one of us here as she knew we were 
writing the article she asked us to !  Anyway that is water under the bridge.
As for authorship we have this article coming out so this rules us 
out. Tom isn't keen and he's away.  Wally told me he didn't reckon Tom, so Tom has 
got the right vibes. Julia is asking us to go ahead and hinting at a joint response . 
One possibility is either you or Macolm taking the lead. Malcom and Henry wrote 
the MWP piece in Climate Change in 94. Keith and I think something pointed about 
the MWP is the way to go. Could add in that even the two warming periods in the 
20th century don't show warming everywhere - especially the early 20th century.
Remember that we are all basically averaging long series together and 
if one site shows a big warming/cooling then the average will to a lesser extent.  
Also bring in a few of the papers where people have compared tree based reconstructions 
with glacial advances/retreats (eg Raper et al in J. Glaciology and Luckman et 
al in the Holocene. Also there are more in that Interhemispheric Linkages Book of 
Vera amd work by Ricardo Villalba and others).
Basically need to point to a load of literature that we would expect 
someone writing an article of this type to be aware of. Also the North Atlantic 
isn't the last word in NH and global averages. Clearly said in Hughes and Diaz and 
papers therein. 
Also the latest IPCC report will use and reference the latest curves, 
but from 1400 they are not that different from Bradley and Jones (1993), so why 
the fuss now.
Clearly the MWP is the issue that has got a few worked up, but we have 
concluded nothing that couldn't have been gleaned in 1994. Maybe we're stating it 
more clearly now, but the recent warmth of the 1990s is a factor as well.


From: "Julia Uppenbrink" To: "Phil Jones" Subject: RE: Science issue Feb 22/23
Date: Mon, 26 Feb 2001 17:05:45 -0000
X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
Importance: Normal

Dear Phil

Thanks for your message regarding Wally Broecker's Perspective. I am of
course aware of this Perspective coming out - I did handle it - I realized
that it was perhaps a bit handwaving in parts but I thought the message was
interesting and the article passed the usual screening. But we are always
open to criticism! So please do send a letter to us; you can send it directly 
to me, and you may cowrite it with Tom Crowley and Mike Mann or you can send 
separate letters (if the concerns overlap a lot then one letter is perhaps 
better than several). The letter will be handled through our lettersdepartment,
and we will get a response from Wally plus possibly outside review before 
we make a decision to publish.

I look forward to receiving your letter.

Best wishes


-----Original Message-----
From: Phil Jones [mailto:p.jones@[gel. W.v.B.]
Sent: 26 February 2001 14:40
To: Julia Uppenbrink
Subject: Science issue Feb 22/23

Dear Julia,
I don't know if you have seen the Perspectives piece in last week's issue of
Science by Wally Broecker.  I guess it was nothing to do with you and it
contains several inaccuracies and sweeping statements. I accept it is a personal
view and I've not seen the issue yet , only a copy that I was ironically given
by Wally Broecker as we were both guest speakers at a meeting at Bowdoin College,
ME on Saturday. I got back this morning to Norwich.
I talked to Wally about it over the weekend and will send him a few reprints
pointing out a few of the things he should have read. Some things he states are 
just wrong.
I don't want to change the article already accepted, but what are the 
possibilities of writing a response to Wally's piece in a later issue. 
I've  been contacted by a couple of people in the US about Broecker's piece 
(Mike Mann and Tom Crowley), who are quite unhappy about it and would like to 
respond. They  both know about the invited piece and wanted me to comment, 
hence my email to you. The invited piece does address some of the issues, but 
not the link between high  and low frequency proxy series.

Best Regards
Schön, dass Phil Jones dasselbe Argument gebraucht, welches ich im Artikel  
Icing the Current Warm Period gebraucht habe: even the two warming periods in 
the 20th century don't show  warming everywhere - 
especially the early 20th century. Remember that we are all basically averaging 
long series together and if one site shows a big warming/cooling then the average 
will to a lesser extent. 

Beliebte Posts aus diesem Blog

Guest Post auf Climate Science

Professor Singer - nachgefragt