« "Apollo - Houston; you are go for landing" | Main | The Ignoble Nobel »
September 28, 2009
What Hockey Stick?
After some prodding (a lot, really), Briffa (a key figure in the climate debate; involved in the 2001 IPCC report), was forced to release the detailed data regarding the tree samples that he used in his data set. (These yielded a 'hockey stick' trend in temperatures).
The result was that only 10 post-1990 tree samples were used; not only is this sample set too small, but those 10 samples were hand picked from a larger set. Steve at Climate Audit found valid samplings from a nearby site and used them as another data point, in the tradition of previous data collections of tree samples (which he enumerates by way of comparison), and the results are staggering. When compared to the hand-picked core samples, there is no 'hockey stick'.
If you're interested in all the nitty gritty, visit Steve's article at Climate Audit . Pay particular attention to entry #10 in the Comments section, which gives a timeline of events and a better synopsis than I am capable of!
Here's an excerpt from the beginning of the post.
Yamal: A "Divergence" Problem
by Steve McIntyre on September 27th, 2009
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-Taymir 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 Taymir 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 Taymir.
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 Taymir 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).
Posted by hanyap at September 28, 2009 4:15 PM
Comments
I don't know If I said it already but ...Excellent site, keep up the good work. I read a lot of blogs on a daily basis and for the most part, people lack substance but, I just wanted to make a quick comment to say I'm glad I found your blog. Thanks, :)
A definite great read..Jim Bean
Posted by: JimmyBean at October 1, 2009 1:19 AM
There's good info here. I did a search on the topic and found most people will agree with your blog. Keep up the good work mate! :)
Posted by: RobD at October 6, 2009 2:32 PM
Hello from Russia!
Can I quote a post in your blog with the link to you?
Posted by: Polprav at October 22, 2009 3:14 AM
Polprav-
Sure! You're welcome to link with my site. No need to ask.
By the way, thanks for the kind words, guys! Appreciate it. =)
Posted by: Hanya at November 4, 2009 4:41 PM