There has been a considerable amount of speculation over the past few years about which “leading” climate scientist told David Deming that we have to “get rid of” the Medieval Warm Period, including speculation (e.g. ukweatherworld) that it was Jonathan Overpeck (recently one of two Coordinating Lead Authors of AR4 chapter 6).
While the identity of Deming’s correspondent remains uncertain, a Climategate letter from January 13. 2005, written as an instruction from Overpeck as Coordinating Lead Author to IPCC Lead Authors Briffa and Osborn (cc Jansen, Masson-Delmotte), states that Overpeck wants to “deal a mortal blow” to the MWP (and Holocene Optimum) “myths” (480. 1105670738.txt).
Subject: the new “warm period myths” box
Hi Keith and Tim -
In reading Valerie [Masson-Delmotte]‘s Holocene section, I get the sense that I’m not the only one who would like to deal a mortal blow to the misuse of supposed warm period terms and myths in the literature. The sceptics and uninformed love to cite these periods as natural analogs for current warming too – pure rubbish.
So, pls DO try hard to follow up on my advice provided in previous email. No need to go into details on any but the MWP, but good to mention the others in the same dismissive effort. “Holocene Thermal Maximum” is another one that should only be used with care, and with
the explicit knowledge that it was a time-transgressive event totally unlike the recent global warming.
Thanks for doing this on – if you have a cool figure idea, include it.
[Update - Apr 10, 2010. In an email on Jul 18, 2005 (551. 1121721126.txt), Briffa wrote Overpeck, Jansen and Crowley, expressing concern about a figure that Crowley had proposed observing:
there are intonations in some of Peck's previous messages that he wishes to "nail" the MWP - i.e. this could be interpreted as trying to say there was no such thing..
To which Overpeck responded: 552. 1121869083.txt
SORRY TO SCARE YOU. I **ABSOLUTELY** AGREE THAT WE MUST AVOID ANY BIAS OR PERCEPTION OF BIAS. MY COMMENT ON "NAILING" WAS MADE TO MEAN THAT ININFORMED PEOPLE KEEPING COMING BACK TO THE MWP, AND DESCRIBING IT FOR WHAT I BELIEVE IT WASN'T.
OUR JOB IS TO MAKE IT CLEAR WHAT IT WAS WITHIN THE LIMITS OF THE DATA. IF THE DATA ARE NOT CLEAR, THEN WE HAVE TO BE NOT CLEAR. THAT SAID, I THINK TOM'S FIGURE CAPTURED WHAT I HAVE SENSED IS THE MWP FOR A LONG TIME, AND BASED ON OTHER SOURCES OF INFO - INCLUDING KEITH'S PROSE. THE IDEA OF A FIGURE, IS THAT FIGURES CAN BE MORE COMPELLING AND CONNECT BETTER THAN TEXT. ALSO, THERE ARE MANY WAYS TO LOOK AT THE MWP, AND AS LONG AS WE DON'T INTRODUCE BIAS OR ANYTHING ELSE THAT WILL DILUTE THE MESSAGE IN THE END, THE IDEA IS TO SHOW THE MWP IN MORE WAYS THAN TWO (THAT IS, THE EXISTING FIGS IN THE TEXT THAT KEITH AND TIM MADE).
Oddly, given Overpeck’s commitment to “dealing a mortal blow” to the “misuse” of the MWP, in another Climategate letter, he didn’t like speculation about him being the one who wanted to “get rid of” the MWP (see 868. 1206628118.txt in March 2008.)
David Holland had written Overpeck, referring to speculation at ukweatherworld that Overpeck was the “get rid of the MWP” scientist, and seeking a statement from Overpeck.
Overpeck wrote to Jones, Mann, Santer, Susan Solomon and Keith Trenberth seeking advice on how to respond, telling them that he didn’t remember any such exchange, but conceding the possibility that Deming is quoting “out of context”:
I have no memory of emailing w/ him, nor any record of doing so (I need to do an exhaustive search I guess), nor any memory of him period. I assume it is possible that I emailed w/ him long ago, and that he’s taking the quote out of context, since know I would never have said what he’s saying I would have, at least in the context he is implying.
Overpeck says that he is reluctant to publish a statement on the matter for fear that Deming would “then produce a fake email”.
Any idea what my reaction should be? I usually ignore this kind of misinformation, but I can imagine that it could take on a life of it’s own and that I might want to deal with it now, rather than later. I could – as the person below suggests – make a quick statement on a web site that the attribution to me is false, but I suspect that this Deeming guy could then produce a fake email. I would then say it’s fake. Or just ignore? Or something else?
Jones wrote back, informing Overpeck that Holland had been making FOI requests, mentioning that he was off with Mann to Tahiti the next week:
I’m away all next week – with Mike. PaleoENSO meeting in Tahiti – you can’t turn those sorts of meetings down!
To a third party, it’s hard to understand why someone who wants to “deal a mortal blow” to the “myth” of the MWP would take exception to being labeled as someone who wanted to “get rid of” MWP. The objective in each case seems pretty much the same.
Maybe it’s just a vocabulary thing. Perhaps Overpeck feels that the term “getting rid of” is a little too Tony Soprano-ish for the “Director of the Institute for the Study of Planet Earth”, whereas the term “dealing a mortal blow” has the right sort of Arthurian cadence for Overpeck, who would rather be cast as Sir Launcelot than Tony Soprano.
Be that as it may, while Overpeck was concerned that Deming might produce a “fake email” purporting to show Overpeck seeking to “get rid of the MWP”, Overpeck hasn’t challenged the authenticity of the Climategate email in which he aspires to “deal a mortal blow” to the MWP.
Postscript: for the nth time, note that the position of the MM articles and many CA posts is that the multiproxy studies relied upon by IPCC do not prove that the modern warm period is warmer than the MWP. This doesn’t mean that we’ve claimed to have established the opposite or that some future scientist couldn’t prove the point with better proxies.