[lbo-talk] climate change

Les Schaffer schaffer at optonline.net
Sat Nov 21 10:06:46 PST 2009


James Heartfield wrote:
> Phil Jones of the Hadley Climate Research Unit explains how he rigged the evidence
>
> 'I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith's to hide the decline.'
> ___________________________________
>

the trick is explained at realclimate.org:

No doubt, instances of cherry-picked and poorly-worded “gotcha”

phrases will be pulled out of context. One example is worth

mentioning quickly. Phil Jones in discussing the presentation of

temperature reconstructions stated that “I’ve just completed Mike’s

Nature trick of adding in the real temps to each series for the last

20 years (ie from 1981 onwards) and from 1961 for Keith’s to hide

the decline.” The paper in question is the Mann, Bradley and Hughes

(1998) Nature paper on the original multiproxy temperature

reconstruction, and the ‘trick’ is just to plot the instrumental

records along with reconstruction so that the context of the recent

warming is clear. Scientists often use the term “trick” to refer to

a “a good way to deal with a problem”, rather than something that is

“secret”, and so there is nothing problematic in this at all. As for

the ‘decline’, it is well known that Keith Briffa’s maximum latewood

tree ring density proxy diverges from the temperature records after

1960 (this is more commonly known as the “divergence problem”–see

e.g. the recent discussion in this paper

<http://www.realclimate.org/index.php/archives/2008/09/progress-in-millennial-reconstructions/>)

and has been discussed in the literature since Briffa et al in

/Nature/ in 1998 (Nature, 391, 678-682). Those authors have always

recommend not using the post 1960 part of their reconstruction, and

so while ‘hiding’ is probably a poor choice of words (since it is

‘hidden’ in plain sight), not using the data in the plot is

completely appropriate, as is further research to understand why

this happens.

http://www.realclimate.org/index.php/archives/2009/11/the-cru-hack

Les



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