I had no complaint with the original Briffa articles — it was
the IPCC spaghetti graph with its false rhetorical effect that bothered me.
I've gone through a laborious process to calculate what the untruncated
IPCC spaghetti graph would look like and show the calculations here.
Not exact matches
Their reconstruction was prominent in the NAS panel
spaghetti graph in 2006 and in the 2007
IPCC AR4 and again in
IPCC AR5.
If
IPCC intended this range of projections to represent their uncertainty range, then that is what they should have shown in AR4 Figure 10.26 (which is more consistent with the Technical Summary than the range in the
spaghetti graph.)
Thus,
IPCC's decision to change the basis of comparison to
spaghetti graph was not done to eliminate an «error» as SKS and others have alleged, but for some other purpose — perhaps to avoid giving «fodder to skeptics», perhaps for some other purpose not yet stated.
However, as Steve has pointed out, none of the
spaghetti graphs used by
IPCC states that there has been «hiding the decline» in the particular
graph.
Post-1960 values of the Briffa MXD series are deleted from the
IPCC TAR multiproxy
spaghetti graph.
-LSB-...] This «apparent» truncation of data had been spotted and discussed at Climate Audit as far back as 2005: Post-1960 values of the Briffa MXD series are deleted from the
IPCC TAR multiproxy
spaghetti graph.
The
IPCC AR5 provides a
spaghetti graph of 95 computer model projections.
The so called «
spaghetti»
graphs used in figure 2 above are interesting, but their range of variability (excepting Moberg et al) remain almost as limited as their iconic predecessor the «Hockey stick» produced by Dr Michael Mann et al and from which the
IPCC third assessment report graphic from 2001 was derived.
And even now, all we have time for is an amusing pasta - related introduction to Steve McIntyre's Swindle and the
IPCC TAR
Spaghetti Graph at Climate Audit.
This
spaghetti graph comes from the
IPCC working group 1 and illustrates twelve multi proxy reconstructions together with their locations, including mbh1999, which has instrumental temperature data added from 1902.
The Yang Chinese composite, after the Mann PC1 and Yamal, had the third - largest hockey stick shape of the proxies illustrated in the
IPCC AR4
spaghetti graph.