Climate Audit

One of the big selling points of Crowley and Lowery [2000] was the “non-synchroneity of temperature change”. One of the key series in showing this was Zhu [1973]. I located Zhu [1973] today. It was great fun, not least for Zhu crediting the teachings of Chairman Mao for inspiring his work. I even reminisce a little about 1968.

Here’s what Crowley said in Crowley and Lowery [2000]:

None of the records between Germany and western China — about 100 degrees of longitude — contribute significantly to peak MWP warming from about 1070-1105.

The four records between Germany and western China are: Briffa’s Polar Urals reconstruction; a tree ring record from Qilian Shan in China, Thompson’s Dunde àƒÅ½à‚ⳏ18 and the phenological reconstruction of Zhu (Chu) [1973].

Readers of this blog will be familiar with Briffa’s Polar Urals reconstruction. (If I don’t post links, google "climateaudit polar urals" and you’ll get to my comments.) This series has an anomalously cold 11th century. It occurs in nearly all of the supposedly “independent” studies. I’ve posted about Briffa’s Polar Urals reconstruction in some detail: its 11th century portion does not meet replication standards (the “cold” 1032 is based on short cores that are almost certainly misdated). Briffa’s reconstruction is also at odds with evidence from tree lines, which were at their highest altitudes in medieval times. Briffa’s Polar Urals is not valid for the 11th century.

Thompson’s Dunde data is also stereotypical in the “independent” studies. It was drilled over 17 years ago and has not been archived. There are several different versions floating around the grey literature, which are inconsistent. [link here] I’ve been trying for over 2 years to look at Thompson’s Dunde data without any success. (It was published in Science.) The first archiving by Thompson occurred last year in response to my intitatives with Climatic Change where Thompson published a review article in 2004, but the data was completely inadequate. àƒÅ½à‚ⳏ18 in monsoon glaciers is strongly determined by “amount effect” and there are real issues about whether the àƒÅ½à‚ⳏ18 at Dunde is a valid temperature proxy.

I haven’t waded through the Qilian Shan tree ring series yet, but it looks like it is a precipitation proxy if anything. Zhu [1973] does indeed have a cold 11th century. However, Zhu [1973] was severely criticized in Zhang [1994] (Zhang being a sometime co-author of Crowley). Zhang [1994] stated that “Chu (1931, 1973) considered the period around AD1200 to be cold. This conclusion was in part based on a set of data on snowfall dates in the South Song Dynasty.” Zhang reported that a recalculation of the calendar conversion from the original lunar calendar to a solar calendar for ancient original records revealed that almost all of the recalculated dates are earlier than thought hitherto: the dates of latest snowfall in the South Song Dynasty should be 8-28 days earlier than previously estimated. “The average date of the latest snowfall for each decade in the South Song time was 27 March, not April 8.” “The South Song time (around 1200 AD) cannot be considered as one of the coldest periods in the last 5000 years in China as previously indicated. In this way a contradiction with the nominal time interval of the Medieval Warm Period (AD900-1300) may be partly resolved.”

Zhang went on to discuss distribution of Boehmeria nivea and citrus trees in the 13th century based on taxation information, showing that distribution in the mid-13th century was north of that in the Tang Dynasty and even further north than the present limit. He concluded that

“the annual mean temperature in the mid-thirteenth century was 0.9 degree C higher, the monthly mean January temperature was 0.6 degree C higher and the mean extreme minimum temperature was probably 3.5 degree C higher than at present”

This is obviously a very different story than Zhu [1973], which has a cold mid-13th century. Why did Crowley use Zhu [1973], when his sometime coauthor Zhang had refuted Zhu [1973] in the MWP? I asked him that question in October 2004 after I got the smoothed Zhu [1973] version from Crowley as follows:

I’m curious about the reasoning in connection with a few series. The Zhu (Chu) 1973 phenological series was criticized by Zhang (Climatic Change 1994) as having incorrect dates from lunar calendar conversions in the 13th century, which then affected the interpretation of the phenology. Why did you use the Zhu version rather than the Zhang version? Also for Tornetrask, you used the Briffa (1990) version rather than the Briffa et al (CLim Dyn 1992) version, which is the version used in other multiproxy studies. Why was that?

Crowley didn’t answer the question. Here’s his response:

with respect to Tornetrask quite simply I cannot recall why – I have subsequently compared some of the Fennoscandian data with Esper’s work – there are differences but I seem to recall the general trends are pretty similar. Note that the purpose of our study was not to produce the best estimate of past temperature change, but to assess the stability of a conclusion about the Medieval Warm Period by including information that discussed this period “¢’‚¬? even if it was not the best information.

Hardly a reassuring answer. Recently in his EOS article, Crowley trashed me for wasting his time with an unending number of questions, but these were hardly unreasonable questions. I’ve had trouble getting Zhu [1973]. The first library that I tried with Scientia Sinica did not have issues before 1982; the second library had the 1973 volume (which was the first volume after a 6 year interruption for the Great Leap Forward), but lacked number 2 containing Zhu [1973]. I left the matter alone for a while. Anyway I finally located Zhu [1973] at the library of the Royal Ontario Museum today. It was great fun. I’ll quote at length from it:

The inconstancy of climate during historical times in China had long been suspected by Chinese philosophers and poets of the Sung (960-1279 AD) and the Ming (1368-1644 AD) Dynasties. As they could not substantiate their case, not much attention was paid to them. By the second decade of the present century, after the May 4th Movement, a movement of anti-imperialism and anti-feudalism in 1919, a new spirit of revolution began to come to life in China. This spirit coupled with the introduction of Marxism-Leninism by the Chinese communists on the one hand and with the systematic excavation of the oracle bones from Yin-Hsu at Anyang, Honan Province on the other, some Chinese historians and geographers began to claim that 3000 years ago, the Yellow River Basin was as warm and wet as the Yangtze River Valley nowadays and that in the past 3000 years, the climate in China underwent many vicissitudes.

But the evidences shown by them were still too fragmentary and they have exaggerated the magnitude and importance of climatic change, which after all, is slow and sporadic compared with changes in human affairs. It was only after the liberation of China in 1949 under the leadership of the Communist Party of China with the establishment of numerous factories, people’s communes and research institutes that science began to forge ahead by leaps and bounds. But more important than that, the teachings of Chairman Mao Tsetung have set free the bounds of authoritarianism of the senior scientists and a new generation of young men of science has begun to sprout up which makes the prospect of future advancement of science full of promise.

According to Chairman Mao:
“In the fields of the struggle for production and scientific experiment, mankind makes constant progress and nature undergoes constant change; they never remain at the same level. Therefore man has constantly to sum up experience and go on discovering, inventing, creating and advancing. Ideas of stagnation, pessimism, inertia and complacency are all wrong. They are wrong because they agree neither with the historical facts of social development over the past million years nor with the historical facts of nature so far known to us (i.e. nature as revealed in the history of celestial bodies, the earth life and other natural phenomena)”

Thus in the sphere of climatology, scholars of the Western world in the early 20th century believed that during historical times the climate over the world had remained practically constant. Such statement is refuted by the abundant facts recorded in Chinese historical annals which we will discuss henceforth. …

Forty or fifty years ago most of the orthodox climatologists of Europe and America believed in the stability of climate during the historical times. According to Julius Hann of Austria, if we had a 30 years’ record of temperature or 40 years record of rainfall of a place, we could establish the normal of that locality and that normal would represent the temperature or precipitation in the long past or for centuries to come. Such misapprehension as only discarded with the accumulation of meteorological data during the recent decades in the world. But in China ancient writers like Shen Kuo, author of the Dream Pool Essays, Chang Piao, author of the Agricultural Essence and Liu Hsien-ting, the writer of Wang Yang Sketches, all doubted the constancy of climate and cited examples of variation of climate recorded in Chinese history and put them in the above above-mentioned books.

Chairman Mao Tsetung in his essay on the “The Role of the Chinese Communist Party in the National War” says:
Our national history goes back several thousand years and has its own characteristics and innumerable treasures. But in these matters we are mere schoolboys. Contemporary China has grown out of the China of the past; we are Marxist in our historical approach and must not lop off our history”.

Like Zhu [1973], we at climateaudit are learning from the Great Helmsman. By applying the lessons of dialectical materialism, Mannianism with its reification of unchanging climate in historical times stands revealed as a projection of the reification of contemporary class structures as absolute rather than being the product of class struggle in a process of dialectical materialism. Thus, Mannianism is an adventurist version of petty bourgeois Hannianism of a century ago. Or perhaps not. Perhaps the above sentence means something. Or perhaps not.

This sort of stuff was just as much a part of the 1960s as Jimi Hendrix or Kent State. It gives me odd reminiscences: in 1968, I travelled round the world. Among other things, I swam across the Ganges at Varanasi (I even have a picture), travelled through the Khyber Pass, was in Gilgit in northern Pakistan in a valley now controlled by Taliban sympathizers when Bobby Kennedy was shot, visited Cambodia before the Pol Pot regime while the Viet Nam war was on. But Daniel (the Red) Cohn-Bendit is Danny the Green today.