Breaking Hockey Sticks- One more time

In case you hadn’t noticed, Steve Malloy of Climate Audit has finally pried loose the data behind the bristle cone pine studies, that formed the basis for Mann’s hockey stick graph, which has been widely accepted as “proof” of global warming by the IPCC. What did he find in the data? I’ll give it to you in his own words:


“The second image below is, in my opinion, one of the most disquieting images ever presented at Climate Audit.

Two posts ago, I observed that the number of cores used in the most recent portion of the Yamal archive at CRU was implausibly low. There were only 10 cores in 1990 versus 65 cores in 1990 in the Polar Urals archive and 110 cores in the Avam-Taimyr archive. These cores were picked from a larger population – measurements from the larger population remain unavailable.

One post ago,
I observed that Briffa had supplemented the Taimyr data set (which had a pronounced 20th century divergence problem) not just with the Sidorova et al 2007 data from Avam referenced in Briffa et al 2008, but with a Schweingruber data set from Balschaya Kamenka (russ124w), also located over 400 km from Taimyr.

Given this precedent, I examined the ITRDB data set for potential measurement data from Yamal that could be used to supplement the obviously deficient recent portion of the CRU archive (along the lines of Brifffa’s supplementing the Taimyr data set.) Hantemirov and Shiyatov 2002 describe the Yamal location as follows:

The systematic collection of subfossil wood samples was begun, in 1982, in the basins of the Khadytayakha, Yadayakhodyyakha and Tanlovayakha rivers in southern Yamal in the region located between 67°00 and 67°50 N and 68°30 and 71°00 E (Figure 1). These rivers flow from the north to the south; hence, no driftwood can be brought from the adjacent southern territories At the present time, the upper reaches of these rivers are devoid of trees; larch and spruce-birch-larch thin forests are located mainly in valley bottoms in the middle and lower reaches.

Sure enough, there was a Schweingruber series that fell squarely within the Yamal area – indeed on the first named Khadyta River – russ035w located at 67 12N 69 50Eurl . This data set had 34 cores, nearly 3 times more than the 12 cores selected into the CRU archive. Regardless of the principles for the selection of the 12 CRU cores, one would certainly hope to obtain a similar-looking RCS chronology using the Schweingruber population for living trees in lieu of the selection by CRU (or whoever).

As a sensitivity test, I constructed a variation on the CRU data set, removing the 12 selected cores and replacing them with the 34 cores from the Schweingruber Yamal sample. As shown below, this resulted in a substantial expansion of the data set in the 19th and 20th centuries and a modest decline in the 18th century. (Hantemirov and Shiyatov 2002 had reported a selection of long cores of 200-400 years; while the CRU archive does not appear to be the precisely the same as the unavailable Hantemirov and Shiyatov 2002 archive, it does appear to be related. This pattern of change indicates that the age of the CRU cores is systematically higher than the age of the Schweingruber cores.) …

Figure 1. Comparison of core count. Black – variation with Schweingruber instead of CRU; red- archived version with 12 picked cores.

The next graphic compares the RCS chronologies from the two slightly different data sets: red – the RCS chronology calculated from the CRU archive (with the 12 picked cores); black – the RCS chronology calculated using the Schweingruber Yamal sample of living trees instead of the 12 picked trees used in the CRU archive [leaving the rest of the data set unchanged i.e. all the subfossil data prior to the 19th century]. The difference is breathtaking.

I hardly know where to begin in terms of commentary on this difference.

The Yamal chronology has always been an exception to the large-scale “Divergence Problem” that characterizes northern forests. However, using the Schweingruber population instead of the 12 picked cores, this chronology also has a “divergence problem” – not just between ring widths and temperature, but between the two versions.

Perhaps there’s some reason why Schweingruber’s Khadyta River, Yamal larch sample should not be included with the Yamal subfossil data. But given the use of a similar Schweingruber data set in combination with the Taimyr data (in a case where it’s much further away), it’s very hard to think up a valid reason for excluding Khadyta River, while including the Taimyr supplement.”

Gee what a surprise. It appears that the data behind Mann’s hockey stick was cherry picked to produce a hockey stick. Accident?, willful academic fraud? I’ll let you decide. The other interesting thing about McIntyre’s analysis of the expanded data set is that it no longer shows the Mideval Warming period as one of the coldest periods in earth’s history. It’s always nice when your analysis matches the history, rather than trying to reinterpret the historical record to fit your analysis.

Will the major media publicize these findings? Will Mann respond in some fashion other than to try to cast aspersions on McIntyre’s credentials? I’m not holding my breath. But in the immortal words of Paul Harvey,”Now you know the rest of the story.”