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To: cogitator

I just read the questions posed to Mann & Co. at M&M's site:

http://www.uoguelph.ca/~rmckitri/research/trc.html

and it doesn't look like he even tries to answer. However, he does try to obfuscate by raising arcane statistical issues.

 Here a letter from Prof. Fred Singer that is a lot more to the point:

Dear All
There is an additional point I would like to add to Aynsley Kellow's
excellent letter:
1. As Knutti/Joos/Stocker correctly point out, the IPCC conclusion, i.e.,
that the 20th century was the warmest in 1000 years, is based on the
instrumental record of surface temperature and NOT on the Mann et al
reconstruction. They should have said "SOLELY based" since Mann et al
stopped in 1980, at which point their temperature did not exceed the
Medieval values.
2. Mann et al do not show proxy temperatures beyond 1980. When I
questioned him regarding this matter 3 years ago, he replied by e-mail that
there were no suitable data available. I had found several proxy records
[1-6] that extended well beyond 1980; none showed higher temperatures.
3. I have now examined several dozen more [7]; again none show higher
temperatures.
4. I conclude therefore that -- contrary to Mann -- many data sets ARE
available; as far as can tell, none agree with the instrumental
SURFACE record; all agree with the satellite and balloon data that show NO
appreciable atmospheric warming trend after 1979.[8]
5. Hence, the IPCC conclusion is not tenable

Best Fred Singer
************************
References:
1. Briffa K.R. 2000.Annual climate variability in the Holocene:
Interpreting the message of ancient trees. Quat. Sci. Rev. 19: 65-73 ;
2. Broecker W. S. 2001. Was the medieval warm period global? Science 291:
1497-1499;
3. Dahl-Jensen, D., Mosegaard, K., Gundestrup, N., Clow, G.D., Johnsen,
S.J., Hansen, A.W. and Balling, N. 1998. Past temperatures directly from
the Greenland Ice Sheet. Science 282: 268-271;
4. Jacoby et al 1996 Mongolian tree rings and 20th century warming, Science
273: 771-773; Jacoby and DArrigo 1997 Proc Natl Acad Sci USA 94: 8351;
5. Naurzbaev, M.M. and Vaganov, E.A. 2000. Variation of early summer and
annual last two millennia inferred from tree rings. J Geophys Res 105:
7317-7326;
6. Thompson L. G. et al. 2000. Ice core evidence for climate change in the
tropics. Science 289: 1916, Fig 6B
7. Singer, S.F. 2003. Science 301, 595 .
8. A full account is submitted for publication elsewhere.

15 posted on 11/03/2003 12:40:24 PM PST by Dan Evans
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To: Dan Evans
I had not seen that Web site; did you read the PDF response from Mann et al.? Here it is:

http://www.uoguelph.ca/~rmckitri/research/EandEPaperProblem.pdf

As it is still "early" in the evaluation of this publication the and controversy that it has created (or is in the process of creating), it appears to me that both sides have succeeded in making the issue confusing and with a seeming atmosphere of ignominy. Meaning: they're succeeding in making a major mess out of this.

Mann's been arrogant, and he didn't treat their requests with respect. (Given the attacks he's been subjected to, MAYBE that's expected, but now he's made it worse.) As for McIntyre and McKitrick, it doesn't look to me like they did the amount of checking and double-checking that they should have done before going to the presses with a major announcement of apparent "bad science" on the part of Mann et al. The subsequent editorializing also shows a impatience to influence public opinion without first doing some fact-checking. The NRO piece by Murray includes some material that previous editorials didn't; I think everybody should have waited about two weeks for the scientific community to weigh in before declaring Mann's work unsound. (To be sure, the editorials don't go quite that far, but they sure make a lot of implications.)

OK, moving on: as previously discussed with "neverdem", Mann et al. used the modern instrumental period to calibrate the proxy temperature data. They call 1902-1980 the "training interval". That allows a comparison of the proxy data to the instrumental data. If more recent proxy data are examined, they can't be directly compared because they haven't been calibrated the same way.

And also note that Singer's claim that the satellite data shown no appreciable warming since 1979 is inaccurate. All analyses of MSU and AMSU tropospheric temperature data shown some degree of warming, ranging from about 0.4 C /century to 1.2 C /century. The current "best" trend from the Spencer and Christy analysis is the MSU2LT data, a combination of MSU and AMSU data, that shows a 0.74 C/century trend.

16 posted on 11/03/2003 1:26:47 PM PST by cogitator
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