The revision of the Copenhagen Synthesis Report was advertised at the ANU Climate Change Institute, directed by Prof. Will Steffen. But they just can’t seem to get it right. The ANU web site refers to Stefan Rahmstorf as Stefan Rahmonstorf.
Ian Castles on the July 5th, 2009 compiled the list of amendments of errors. Below is an update of the current situation.
A summary chronology:
(1) According to the first sentence in the caption to Figure 3 of the Copenhagen Synthesis Report, as released on 18 June,
the Figure showed “Changes in global average surface air temperature (smoothed over 11 years) relative to 1990.”
(2) On 25 June, Jean S queried Stefan Rahmstorf at RealClimate about the â€œsmoothed over 11 yearsâ€, asking â€œDid you change the filter length from M=11 to M=14 in the temperature graph (Figure 3)?â€
(3) On 30 June or thereabouts, Dr Rahmstorf replied â€œAlmost correct: we chose M=15. In hindsight the averaging period of 11 years that we used in the 2007 Science paper was too short to determine a robust climate trendâ€¦â€
(4) On 3 July or thereabouts, the first sentence of the caption to the Figure was amended so as to read: “Changes in global average surface air temperature (smoothed over 15 years) (corrected from 11 in the first version of this report) relative to 1990.”
This could be taken to mean that the smoothing in Figure 3 shown in the first version of the Copenhagen Report was over 11 years, but that this had now been corrected to 15 years. But in fact, it is only the caption that has been corrected, not the Figure itself.
(5) In the light of the postings of 4 July at #79 and #88 above, it now seems that the caption should be further revised to say that the smoothing is over 29 years.
6. The typo in the caption of Figure 3 has been uncorrected since at least 17 July and reads “corrected from 11 in the first version og this report”.
7. A comment on the inaccurate description of the procedure in the caption by Hu McCulloch remains in moderation at RealClimate for over 7 days.
Hu McCulloch says:
Your comment is awaiting moderation.
19 Jul 2009 at 9:38 am
8 Jul 2009 at 7:07 am
Stefan, the caption is incorrect. It says â€™smoothed over 15 yearsâ€™. There is no possible ambiguity of interpretation of this. 29 years are involved in your smoothing, so it should say â€™smoothed over 29 yearsâ€™.
[Response: I think we have to agree to disagree here. It is quite common to characterise filters by their half-power width (as is indeed very familiar for Gaussian filters), since this is more informative about their response than citing the number of points involved in the calculation. -stefan]
I find your recommended half-power period for the SSA filter using M = 15 (29 weights) to be 45.9 years. The half-amplitude period, which is perhaps more useful outside of electronics, is still 33.0 years. See graphs of the amplitude response here [link to #178 above].
Wouldnâ€™t it then be more appropriate to call your filter 33- or 46- year smoothing, depending on the measure, rather than 15? Or do you get different values?
They are in between a rock and a hard place at the moment. To revise the report again would look like they are puppets to a few bloggers, and incapable of producing accurate science on their own. To leave the report as it is, with the misrepresentation of the methodology used in Figure 3, together with the “og” typo, is just an embarrassment.
The dilemma is made worse by the big-noting of the accuracy and editorial throughness of the information presented in the preface:
This report has been critically reviewed by representatives of the Earth System Science Partnership (ESSP)ii, by the parallel session chairs and co-chairs, and by up to four independent researchers from each IARU university. This extensive review process has been implemented to ensure that the messages contained in the report are solidly and accurately based on the new research produced since the last IPCC Report, and that they faithfully reï¬‚ect the most recent work of the international climate change research community.
There is another difficulty. Because Rahmstorf increased the duration of smoothing in Figure 3 so that global temperatures did not show the recent cooling, the reference to his (now throughly discredited) Rahmstorf et al 2007 is not accurate, and the analysis is essentially “orphaned”.
For 7 days, they have simply put their head in the sand. The root of the problem is the typical strategy used in climate science of eschewing of “engineering-quality studies“, in favor of emotional appeals to the general public with glossy brochures, the purpose of which is primarily to advertise the UN Conference on Climate Change to be held in Denmark December 09.