Steve McIntyre
Climate Audit
Thursday, April 8, 2010

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.
Best, peck
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.