Science > Abortion > Oops, Anti-Global Warming Article Turns Out to Be Flawed (GOP=Junk Science)
| Topic: |
Science > Abortion |
| User: |
"Yang, AthD h.c, Kicking AWOLs Cocaine Snorting Ass" |
| Date: |
04 May 2006 12:35:01 AM |
| Object: |
Oops, Anti-Global Warming Article Turns Out to Be Flawed (GOP=Junk Science) |
Let's review GOP "science"
Tobacco is not addictive
There is no evidence for evolution
There is no global warming
Breathing coal dust into your lungs is healthy
No one dies from asbestos
http://www.realclimate.org/index.php/archives/2006/04/a-correction-with-repercussions/
Today, Science published an important comment pointing out that there
were serious errors in a climate research article that it published in
October 2004. The article concerned (Von Storch et al. 2004) was no
ordinary paper: it has gone through a most unusual career. Not only
did it make many newspaper headlines [New Research Questions
Uniqueness of Recent Warming, Past Climate Change Questioned etc.]
when it first appeared, it also was raised in the US Senate as a
reason for the US not to join the global climate protection efforts.
It furthermore formed a part of the basis for the highly controversial
enquiry by a Congressional committee into the work of scientists,
which elicited sharp protests last year by the AAAS, the National
Academy, the EGU and other organisations. It now turns out that the
main results of the paper were simply wrong.
Von Storch et al. claimed to have tested the climate reconstruction
method of Mann et al. (1998) in model simulations, and found it
performed very poorly. Now, Eugene Wahl, David Ritson and Caspar Amman
show that the main reason for the alleged poor performance is that Von
Storch et al. implemented the method incorrectly. What Von Storch et
al. did, without mentioning it in their paper, was to remove the trend
before calibrating the method against observational data - a step that
severely degrades the performance of Climate Field Reconstruction
(CFR) methods such as the Mann et al. method (unfortunately this
erroneous procedure has already been propagated in a paper by Burger
and Cubasch (GRL, 2005) where the authors refer to a personal
communication with Von Storch to justify the use of the procedure).
Another more recent analysis has shown that CFR methods perform well
when used correctly. (See our addendum for a less technical
description of what this is all about).
How big a difference does this all make? The calibration error in the
temperature minimum around 1820, where one of the largest errors
occurs, is shown as 0.6șC in the standard case of 75% variance in the
Von Storch et al analysis. This error reduces to 0.3șC even in the
seriously drift-affected ECHO-G run when the erroneous detrending step
is left out. In the more realistic HadCM3 simulation, this error is
just above 0.1șC. The error margins (2 sigma) provided by Mann et al.
and pictured in the IPCC report are ±0.17șC (Fig. 2.21, the curves are
reproduced in our addendum). It is therefore clear that the model test
of Von Storch et al, had it been implemented correctly, would have
shown a small but undramatic underestimation of variance and would
have barely ruffled a feather.
Error made, error corrected, and all is well? Unfortunately not. A
number of questions remain, which need to be resolved before the
climate science community can put this affair to rest.
The first is: why did it take so long to correct this error, and why
did the authors of the original paper not correct it themselves? The
error is reasonably easy to spot, even for non-specialists (see
addendum). And it was in fact spotted very soon after publication. In
January 2005, a comment was submitted to Science which correctly
pointed out that Von Storch et al. had calibrated with detrended data
and had therefore not tested the Mann et al. method. As such comments
are routinely passed to the original authors for a response, Von
Storch et al. must have become aware of their mistake at this point at
the latest. However, the comment was rejected by Science in May 2005.
In a paper dated July 2005, Zorita and Von Storch admit their error in
passing, writing: "the trend is subtracted prior to the fit of the MBH
regression/inflation model (von Storch et al. 2004). [...] It seems,
however, that MBH have exploited the trends". It is thus clear that
they knew that their central claim of the Science paper, namely that
they had tested the Mann et al. method, was false. But rather than
publishing a correction in Science, they wrote the above in a non-ISI
journal called "Memorie della Societa Astronomica Italiana" that not
many climatologists would read.
An unambiguous correction in Science, where the original paper
appeared, would not only have been good scientific practice. It would
have been particularly important given the large public and political
impact of their paper. It would have been a matter of courtesy towards
their colleagues Mike Mann, Raymond Bradley and Malcolm Hughes, who
had suffered a major challenge to their scientific reputations as well
as having to invest a large amount of time to deal with the
Congressional enquiry mentioned above. And it would have been
especially pertinent given the unusually vitriolic media statements
made previously: in an interview with a leading German news magazine,
Von Storch had denounced the work of Mann, Bradley and Hughes as
"nonsense" ("Quatsch"). And in a commentary written for the March 2005
German edition of "Technology Review", Von Storch accused the journal
Nature for putting their sales interests above peer review when
publishing the Mann et al. 1998 paper. He also called the IPCC
"stupid" and "irresponsible" for highlighting the results of Mann et
al. in their 2001 report.
There were at least two further issues with the Von Storch et al.
paper:
- The model run of Von Storch et al. suffers from a major climate
drift due to an inappropriate initialisation procedure. Despite
starting in medieval times, the model was initialised from a
present-day, rather than pre-industrial, climate state - i.e. from a
climate affected by human-caused warming. As a result, the Northern
Hemisphere temperature in the model drops by about 1.5 șC during the
initial 100-year adjustment phase and keeps drifting down for the
coming centuries. This problem is never mentioned and this part of the
experiment is not shown in publications, although climate modellers
know that such severe disequilibrium must cause a long-lasting climate
drift in the remainder of the run. After Osborn et al. (2006)
documented this problem, Von Storch et al. repeated their experiment
with improved initialisation. Their new run shows that about half the
cooling from medieval times to the 19th Century in their original
paper was due to this artificial drift, but again they have not
published a correction or demonstrated the impact of this issue (see
addendum).
- Von Storch et al. also looked at another model, stating: "Similar
results are obtained with a simulation with the third Hadley Centre
coupled model (HadCM3), demonstrating that the results obtained here
are not dependent on the particular climate characteristics of the
ECHO-G simulation." They have repeatedly made similar claims in the
media. This is important, as any model result is considered somewhat
preliminary until confirmed with an independent model. However, their
statement appears to us to be a serious misrepresentation of the
HadCM3 results which were shown only in the online supplement to their
paper (see addendum).
In their response to the Wahl et al critique, Von Storch et al
acknowledge the original problem but in order to salvage their result,
they introduce a large 'red noise' component into the proxies. This
changes the nature of their test and implies an 'a priori' loss of low
frequency variance instead of trying to calculate whether a particular
methodology produces such a loss.
One could view this story as a positive example for the
self-correcting process of science: erroneous results are eventually
spotted and corrected, even if it sometimes takes time. If only
science were at stake here, we'd need say no more: this would have
been a sometimes inappropriately sharp, but otherwise regular
technical debate about improving the methodology of proxy
reconstructions.
Unfortunately, while the dispute has been used in the public arena to
score political points, e.g. to discredit the IPCC process and to
question all of the relevant climate science, the significance of this
dispute for the bigger picture has been wildly blown out of proportion
(see here for a previous discussion). We hope that after this new
correction, the discussion can move on to a more productive level. The
key issue is how we can improve reconstructions of past large-scale
climate variability - of which by now almost a dozen exist. We should
not lose sight of the fact that the debate here is about a few tenths
of a degree - a much smaller change than is projected for the next
century. It is also important to remember one principal point:
Conclusions on whether recent warmth is likely to have been
unprecedented in the past millennium, or the recent extent of
human-caused warming, are based on the accumulation of evidence from
many different analyses and are rarely impacted by a technical dispute
about any one paper such as this.
-----
Yang
a.a. #28
AthD (h.c.) conferred by the regents of the LCL
a.a. pastor #-273.15, the most frigid church of Celcius nee Kelvin
EAC Econometric Forecast and Sorcery Division
The Bush 'balanced' budget: 2 trillion and worsening
The Bush 'economic' policy: 12.5 million FEWER jobs than Clinton and counting
The Bush Iraq lie: -2405 GIs, one friend's co-worker's son and mounting
Having Bush ***** up my country: Worthless
-----
"Ahhhhhh, yessssssss, ummmmmmm - Alito, Alito, Alito"
-duke (duckgumbo@cox.net), aka PedophilEarl J Weber, 59
year old mateless, heirless biological failure
of Afton Oaks Apartment, Baton Rouge,who pussied
out of the Vietnam draft, showing his gay side
despite his avowed anti-gay bigotry
Contact duke's priest and ask
him why duke is such a racist:
http://www.stpatrickbr.org/
Father Gerard "Jerry" Martin
stpatrickbr<AT>bellsouth<DOT>net
Saint Patrick Catholic Church
12424 Brogdon Lane
Baton Rouge, Louisiana 70816
.
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