Thursday, October 01, 2009

Yamal Replies

Both Keith Briffa and RealClimate have replied to the Yamal accusations, and you get the impression they're a little pissed (but too professional to admit it). And you can't blame them, with all the unfounded accusations of malfeasance so quickly and irresponsibly tossed around. You'd get pissed too.

As usual, there's no there in any of the accusations. Here's Briffa:
The basis forThe substantive implication of McIntyre's comment (made explicitly in subsequent postings by others) is that the recent data that make up this chronology (i.e. the ring-width measurements from living trees) were purposely selected by me from among a larger available data set, specifically because they exhibited recent growth increases.
This is not the case. The Yamal tree-ring chronology (see also Briffa and Osborn 2002, Briffa et al. 2008) was based on the application of a tree-ring processing method applied to the same set of composite sub-fossil and living-tree ring-width measurements provided to me by Rashit Hantemirov and Stepan Shiyatov which forms the basis of a chronology they published (Hantemirov and Shiyatov 2002). In their work they traditionally applied a data processing method (corridor standardisation) that does not preserve evidence of long timescale growth changes. My application of the Regional Curve Standardisation method to these same data was intended to better represent the multi-decadal to centennial growth variations necessary to infer the longer-term variability in average summer temperatures in the Yamal region: to provide a direct comparison with the chronology produced by Hantemirov and Shiyatov.

He continues:
McIntyre's selection of which of our (i.e. Hantemirov and Shiyatov's) data to exclude and which to use in replacement is not clear but his version of the chronology shows lower relative growth in recent decades than is displayed in my original chronology. He offers no justification for excluding the original data; and in one version of the chronology where he retains them, he appears to give them inappropriate low weights. I note that McIntyre qualifies the presentation of his version(s) of the chronology by reference to a number of valid points that require further investigation. Subsequent postings appear to pay no heed to these caveats. Whether the McIntyre version is any more robust a representation of regional tree growth in Yamal than my original, remains to be established.

And here's RealClimate getting to what I think is the heart of the matter:
There is nothing wrong with people putting together new chronologies of tree rings or testing the robustness of previous results to updated data or new methodologies. What is objectionable is the conflation of technical criticism with unsupported, unjustified and unverified accusations of scientific misconduct. Steve McIntyre keeps insisting that he should be treated like a professional. But how professional is it to continue to slander scientists with vague insinuations and spin made-up tales of perfidy out of the whole cloth instead of submitting his work for peer-review? He continues to take absolutely no responsibility for the ridiculous fantasies and exaggerations that his supporters broadcast, apparently being happy to bask in their acclaim rather than correct any of the misrepresentations he has engendered. If he wants to make a change, he has a clear choice; to continue to play Don Quixote for the peanut gallery or to produce something constructive that is actually worthy of publication.

Jennifer Mahasoy absurdly called for CRU scientists to resign over this manufactured scandal. Think she or McIntyre will have the integrity to fall on their own swords?

At the very least, McIntyre owes Briffa an apology.


Mailman said...

If McIntyre is so wrong and the global warming science is so settled...why not make ALL the data used by Biffra et al available?

By not making their data available, and I mean EVERYTHING, what are they trying to hide?

Surely, as a person interested in science, all you are interested in is getting to the truth?

If McIntyre is wrong, let the data prove he is wrong.



Hank Roberts said...

And the crap spin on this is already coming in.

You got one there already, from some netwit who isn't reading and didn't notice that the info has been available for a long time. It's the "there must be more because we don't have what we imagine yet" approach, also known as "there must be a pony."

The other commonly plopped misunderstanding is posts claiming that Briffa acclaims something McI wrote as having has "valid points ...."

These people can't read.

Anonymous said...

The Yamal series data was published in 2000, was used extensively in numerous science and nature papers, and has not been available for critical appraisal until this year.

It turns out that a key part of the chronology (post 90) has only ten trees; a standard which is extremely weak evidence.

We can now point out that there are lots of important papers (climate reconstructions) whose conclusions are seriously changed by removal of the chunk with ten trees.

It is also apparent that you need some rational reason for preferring Yamal over a nearby site- other than cherry-picking the result you want.

These are not trivial issues; they go to the heart of whether this science is reproducible.

Isn't it good that we can have this debate about the science ?

TDK said...

It doesn't seem to me that McIntyre was creating a new chronology but rather, testing the robustness of the existing one.