Date: Fri Jul 23 15:29:11 2004
Maybe Steve sent you the two emails I've resent. Ignore my ramblings at the end of one,
but I was getting a little fed up. The Legates email is at the end, in case you're
The pdf is worth a read. Odd that he writes a press release, then starts working on a
We've very occasionally written a press release, but only after the paper has come out.
I tried to explain the 'missing' rings. They aren't missing, but due to the samples not
being right for density measurements. All Schweingruber's chronologies are constructed
this way - traditional ring width measurements aren't made. Some of the Russian groups
he's worked with have added extra ring width cores and sometime get longer series, but
all the data Keith and I work with is from Fritz, so if density is missing, then RW is
Fritz did almost all the coring - 99% of the sites. We only help coring on a couple of
This comes from alignment tracking as you say, but Fritz also says it is partly due to
the need to extract the lignin and to avoid resin. When we cored together, he was always
saying we weren't doing it properly getting twisted cores. I'm not a proper dendro
as I only got into this because of Keith - it may not be lignin, but something has to be
extracted with solvents.
The Polar Urals site was collected by Fritz and Stepan Shiyatov. There are living trees
back to the 1500s and then stumps at a slightly higher elevation. Stepan has been back
more recently and regeneration is occurring at higher levels, but it is taking time. Tree
take a while to respond to the recent warmth in some regions. Once the trees are
and not killed by frosts/snow in winter they survive even if it gets cooler. I discussed
in a review paper in RoG attached. The section on the issue is brief.
All the cores were collected over a couple of days. Fritz made a mistake with the
for one core and that explains the 400 years of missing values. Someone at WDCP
must have combined the cores with the same ids. Dendro people are always looking for the
oldest trees and we kept the earliest series in. Steve seems to have a thing about these
and the 10th and 11th centuries, but they are correctly dated. Fritz uses loads of plots
and pointer years and doesn't make mistakes normally. There is a very distinct year at
AD 1032. Fritz is also cross dating with LWW and EWW and other features and not just
on RW. I say not just, he normally does with density. At the coring stage Fritz had no
of the ages of the stumps (well just the number of years). There may have been samples
off the front that couldn't be dated at all, for all I know. I suspect though they are
the same calendar age, as the site has distinct dates for the start of trees, which
regeneration periods. Maybe you can try and explain the tree-line argument to Steve.
When he had to omit parts of cores, he was always able to know where the two parts sat
in the sequence. We need to keep them together to do things like RCS.
Anyway, I have to go home - it's been very wet lately and the grass has grown. The
lawn must be mowed when the sun shines.
Keep pushing that he should write up what he does (and Ross) in proper journals. E&E
and Climate Research are not read by many now. I only look at them when I get
alerted and I remain exasperated.
Phil Jones has made a valid point in that some of the articles cited
in my critique do not 'directly' address problems with Mann and Jones (MJ)
but rather, address problems with earlier works by Mann, Bradley, and
Hughes (MBH) and other colleagues. Fair enough - I have changed the
critique to reflect that fact. The revised version has been posted since
July 19 at:
However, I still contend that most of my original arguments - namely, the
problems with the shaft, blade, and sheath - apply equally to Mann and
Jones as well as the other Mann et al. manifestations of the 'hockey
MJ incorporate data from a number of the same sources as those used
by MBH; for example, Mann's unpublished PC1 from the western North
American tree-ring data, Cook's Tasmanian tree rings, Thompson's Quelccaya
and Dunde ice core oxygen isotope records (the latter embedded in Yang's
Chinese composite), and Fisher's stacked Greenland ice core oxygen isotope
record. Calibration and verification of MJ includes the flawed MBH curve.
Thus, any errors in MBH effectively undermine the calibration-verification
results of MJ, leaving this study unsupported and any problems with the
underlying common proxies identified in critiques of MBH will also result
in identical problems in MJ.
My criticism regarding the blade is that 0.6 deg C warming for the
last century is noted by the IPCC whereas MJ (and other M et al
representations) have up to 0.95 deg C warming in their observed record.
See MJ's figure 2 where for the global and NH reconstruction, their
estimates for 2000 exceed +0.4 and +0.5 (nearly +0.6), respectively.
MJ's NH curve is included in the attached graph. Thus, I stand by my
criticism of MJ on this point, which is more egregious in MJ than other M
et al representations.
>From Jones: "The trend over the 20th century in the Figure and in the
instrumental data. IPCC quotes 0.6 deg C over the 1901-2000 period. Fact
- but Legates is eyeballing the curve to get 0.95 deg C. A figure isn't
given in Mann and Jones (2003). Take it from me the trend is about the
same as the instrumental record."
Funny, but there IS a figure in MJ - see their Figure 2. As for me
'eyeballing' an apparently non-existent curve, I attach a figure from Soon
et al. (2004) that contains a portion of MJ's Figure 2 to allow others to
decide for themselves whether MJ suggest a twentieth century warming of
0.6 deg C or 0.95 deg C. Moreover, maybe someone can explain why every
time Mann and his colleagues draft another curve, the temperature in 2000
gets warmer and warmer after the fact...
My criticisms regarding the sheath (largely from a paper on which I
am working) stem from the characterization of the uncertainty by MJ that
arises solely from the 'fit' statistics to the 1600-1855 period using
cross-validation with, not observations, but composites of three
previously compiled reconstructions, including that developed by MBH - the
focus of known flaws and errors in the shaft. Note that some of the same
data are used in both MBH and MJ, which doesn't allow for a truly
independent cross-validation. My rather obvious point was not that fit
statistics should not be included (as Jones asserts) but that MJ included
no errors in either input realization (observations or proxy data) or
other obvious sources of error. The claim by MBH and MJ is that only the
model lack-of-fit contributes to uncertainty is inherently flawed.
Considerable errors exist in the representation of both fields -
annual temperatures from both observations and proxy records - and must be
incorporated. Clearly, there is a spatial bias associated with
observations that are biased away from the oceans, high latitudes, and
high altitudes. The spatial problem is far more pronounced when only a
handful of proxies are used to represent the global temperatures at
earlier time periods. Both MBH and MJ are equally guilty in this regard.
David R. Legates
Several people have asked me for the full references to the works I have
cited. They are:
Chapman, D.S., M.G. Bartlett, and R.N. Harris (2004): Comment on 'Ground
vs. surface air temperature trends: Implications for borehole surface
temperature reconstructions' by M.E. Mann and G. Schmidt. Geophysical
Research Letters, 31, L07205, doi:10.1029/2003GL019054.
Esper, J, E.R. Cook, and F.H. Schweingruber (2002): Low-frequency signals
in long tree-ring chronologies for reconstructing past temperature
variability, Science, 295, 2250-2253.
Esper, J, D.C. Frank, and R.J.S. Wilson (2004): Climate reconstructions:
Low-frequency ambition and high-frequency ratification. EOS, Transactions
of the American Geophysical Union, Vol. 85 (12):113,120.
IPCC TAR (Intergovernmental Panel on Climate Change, Third Assessment
Report) (2001): Climate Change 2001: The Scientific Basis, Houghton,
J.T., Ding, Y., Griggs, D.J., Noguer, M., van der Linden, P. J., Dai, X.,
Maskell, K., Johnson, C.A. (Eds.), Cambridge University Press.
Mann, M.E., R.S. Bradley, and M.K. Hughes (1998): Global-Scale
Temperature Patterns and Climate Forcing Over the Past Six Centuries,
Nature, 392, 779-787. [see also the correction in Nature - Mann, Bradley,
and Hughes, 2004]
Mann, M.E., R.S. Bradley, and M.K. Hughes (1999): Northern Hemisphere
Temperatures During the Past Millennium: Inferences, Uncertainties, and
Limitations. Geophysical Research Letters, 26, 759-762.
Mann, M.E., and P.D. Jones (2003): Global surface temperature over the
past two millennia, Geophysical Research Letters, 30(15), 1820, doi:
Mann, M.E., and G. Schmidt (2003): Ground vs. surface air temperature
trends: Implications for borehole surface temperature reconstructions.
Geophysical Research Letters, 30(12), 1607, doi:10.1029/2003GL017170.
McIntyre, S., and R. McKitrick (2003): Corrections to the Mann et al
(1998) Proxy Data Based and Northern Hemispheric Average Temperature
Series. Energy and Environment, 14, 751-771.
Pollack, H.N., and J.E. Smerdon (2004): Borehole climate reconstructions:
Spatial structure and hemispheric averages. Journal of Geophysical
Research, 109, D11106, doi:10.1029/2003JD004163.
Rutherford, S., and M.E. Mann (2004): Correction to 'Optimal surface
temperature reconstructions using terrestrial borehole data'. Journal of
Geophysical Research, 109, D11107, doi:10.1029/2003JD004290.
Soon, W.-H., S.L. Baliunas, C. Idso, S. Idso, and D.R. Legates (2003):
Reconstructing Climatic and Environmental Changes of the Past 1000 Years:
A Reappraisal. Energy and Environment, 14:233-296.
Soon, W.-H., D.R. Legates, and S.L. Baliunas (2004): Estimation and
Representation of Long-Term (>40 year) trends of
Northern-Hemisphere-gridded Surface Temperature: A Note of Caution.
Geophysical Research Letters, 31(3).
Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email email@example.com