MiniMax says: “Looks to me like ~1100 BP (or around 900 AD[…])


MiniMax says: “Looks to me like ~1100 BP (or around 900 AD[…])


In short, the medieval warm period makes no political difference to thinking people concerned with climate change. It may tell them something about how the Earth behaves climatically over long periods, which would be great (although if you take a long enough view we’re all going to bake or sink anyway), but it certainly doesn’t mean we don’t need to cut emissions, carbon or otherwise, combat overfarming, deforestation and salination, come up with alternative energy sources good and fast and start in on the synthetic food. It really affects none of these necessities. But it did affect my subject population, or so it seems, really quite a lot. So dammit, you kids, get out of my yard.


Of course, all this is may be merely coincidence.

Perhaps it’s just a matter of style, John, but I’d rather express the conclusion by using this rhetorical pattern from the auditing sciences:

A closer re-examination of the documents adds circumstantial support against Deming’s recollection.

We emphasize “circumstantial” and “against”, of course.

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The idea that present temperatures are “unprecedented during the past several centuries” was definitely not original to the Mann hockey stick, as this view dated back to at least Hubert Lamb and could be said to be a consensus view.

The Auditor, seemingly entertaining a change of faith in his exegesis of the canons of one of his guru.
(via Extract from pages 171-172 of H. Lamb’s ‘Climate, History and the Modern World’ 1982. - Causes and Consequences of the Medieval Warm Period)

Dancing on Human Volcanoes

[William Connoley shared this old climatic tale by Michael Tobis, starting with a professor he knew, Reid Bryson. This might help elucidate the “paradigm shift” from Lamb to Wigley at CRU.]

Bryson coined the term “human volcano” to designate the human output of particulates, which he feared might contribute to triggerring the then plausible scenario of a sudden onset ice age. (Contrary to Niven and Pournelle’s ridiculous botch in their science fiction novel Fallen Angels, this is no longer considered plausible. See Crowley & North, Paleoclimatology, Oxford U press, 1991, pp 121-122.)

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"We have to get rid of the Medieval Warm Period!" (via ScootleRoyale, courtesy of John Mashey).

Further Corrections

[Tom Curtis reports interesting details about the Lamb graph. Note how Steve tries to ignore Curtis’ point while attacking Curtis’ person.]

In 2001 Daley wrote:

In 1995, the Intergovernmental Panel on Climate Change (IPCC) released its 5-yearly report on climate change [10], in a blaze of publicity, which contained the now infamous phrase that there was “a discernible human influence on global climate. Also contained in this report but attracting less attention, was an assessment of how global climate had changed, not just during the previous 95 years, but also the past 1,000 years. In so doing they presented this graph (Fig 1.) of temperature change since 900 AD.


That wording is retained on Feb 1st, 2003, but changes to an attribution of the graph to IPCC 1990 in Nov 3rd, 2003. Apparently I was incorrect about 2004, Daley corrected the attribution earlier than that.

Steve’s update reference to “at that time” is vague. The natural interpretation (IMO) is that it refers to the time in 2008 when you diagnosed the provenance. However, in 2007 Connolley diagnosed the attribution to Lamb on Wikipedia (see linked page previously by Connolley and myself). You either need to correct the claim that he did not know the source to read that he had noted it resembled a graph by Lamb, or amend the time reference so that it explicitly refers to 2005.

Daley corrected the attribution between Feb 1st 2003 and June 26th 2003:


Medieval scholars and sailors did NOT believe the earth was flat. The scholars knew from ancient Greek philosophers the exact diameter of the earth.

Michael Reed, a bit upset when Brooks Hurd uses that meme to editorialize about AGW in a comment thread of a shout-out to a Ridley’s review of our beloved Bishop Hill’s political hit job.
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