[asa] peer review and checking the math

From: PvM <pvm.pandas@gmail.com>
Date: Thu Dec 07 2006 - 12:05:11 EST

So let's continue with the search for the truth

-------------Janice Wrote----------
1] Global warming began when the doom-mongers cast off their thermal
underwear, climbed into
the leopardskin thongs, slathered themselves in sun cream and wired
their publishers to change
all references to "cooling" to "warming" and voila! - in 1970 the
planet stopped its very
slight global cooling and began to undergo very slight global warming.
But then in 1998 the
planet stopped its very slight global warming and began to resume very
slight global cooling. It
was at this time that the doom-mongers said, "Look, do we really want
to rewrite the bumper
stickers every 30 years? Let's just call it 'climate change.' That
pretty much covers it."
-----------end quote-------------

Janice is confounding 'trend' with individual measurements. Since the
latter are noisy, one has to be careful to look at any give data point
and draw conclusions, especially about trends.

In fact the real temperature data shows, as expected, an unusual warm
1998 El Nino year with continued warming trends. Bob Carter seems to
have started this 'argument' and as our friend Lambert shows, the
argument is one of cherry picking

http://www.scienceblogs.com/deltoid/2006/04/a_picture_is_worth_a_thousand.php

See also the top picture in Wikipedia
http://en.wikipedia.org/wiki/Global_warming

Cherry picking data is not the best way to support one's argument.
And the Freerepublic seems to not be the best source of one's
information, especially when it comes to science.

And so we all learn something useful.

About peer review, McKitrick and Mann, we hear from Janice

--------Janice wrote------------
A consistant theme that has been discovered is that the "peer review"
in climate science studies has never involved checking the math. When
MacIntyre and McKitrick asked to see the information that was
forwarded by various "peer-reviewed" journals, more than one editor
claimed that no one had *ever* asked for the data so that the math
could be checked (citing various times they'd been editor, including
some over 20 years), or to determine if the processes described in the
paper were in fact what duplicable. Who "checks the math"? Basically
just associates of Mann and Jones.
------------end quote------------

Peer review by the NRC/NAS found very similar conclusions. As too
checking the math, McKitrick's math was corrected by Lambert who found
out that McKitrick had forgotten to transform his latitudes from
degrees to radians before feeding them to a function that expected the
latter. Once corrected, the results failed to support McKitrick's
earlier claims.

http://www.realclimate.org/index.php?p=8 adds additional information
about McKitrick and Mann.

----Begin Quote----
 In stark contrast, our reproduction of the MM reconstruction
demonstrates that their reconstruction dramatically fails statistical
verification (see Figure 5) with an RE score ( -0.76) that is
statistically indistinguishable from the results expected for a purely
random estimate (as a reminder, RE<0 exhibits no skill, and RE= -1 is
the average value expected for a purely random estimate). In short,
the supposed 'correction' of MBH98 by MM is seen to represent little
more than a statistically meaningless, botched application of the
MBH98 procedure that relies upon censoring key indicators from the
MHB98 proxy data set.
----end Quote------

Botched math indeed.

From a 2005 paper by Rutherford we learn that

-------begin quote-------
It should be noted that some falsely reported putative errors in the
Mann et al.(1998) proxy data claimed by McIntyre and McKitrick (2003)
are an artifact of (a) the use by these latter authors of an incorrect
version of the Mann et al. (1998) proxy indicator dataset, and (b)
their misunderstanding of the methodology used by Mann et al. (1998)
to calculate PC series of proxy networks over progressively longer
time intervals. In the Mann et al. (1998) implementation, the PCs are
computed over different time steps so that the maximum amount of data
can be used in the reconstruction.
------end quote------
Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R.,
Hughes, M.K., Jones, P.D., Proxy-based Northern Hemisphere Surface
Temperature Reconstructions: Sensitivity to Methodology, Predictor
Network, Target Season and Target Domain, Journal of Climate, in press
(2005).

And a quick drive-by of the hockey stick arguments:
http://www.realclimate.org/index.php?p=98
Especially of relevance is how the eigenvalues are above the random noise level:
http://www.realclimate.org/index.php?p=9#figure

On 12/7/06, Carol or John Burgeson <burgytwo@juno.com> wrote:
> >>Which is why
> Al Gore's documentary,>>
>
> My review of Gore's book was just accepted by PERSPECTIVES.
>
> I'll have it on my web site in a week or two.
>
> >>I am still not clear why Janice seems to be so opposed to these clear
> findings? Is it based on science? Faith? Hearsay?>>
>
> True believers get that way by concentrating only on those sources which
> agree with them. The YECs are particularly guiltty of this, I think.
>
> John
>

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Received on Thu, 7 Dec 2006 09:05:11 -0800

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