[ExI] Phil Jones acknowledging that climate science isn'tsettled
max at maxmore.com
Thu Feb 18 02:00:26 UTC 2010
See this is what happens... I'm spending way too
much time on a point that really doesn't
matter... I just find it frustrating that it's
difficult to come to a conclusion even about a
relatively narrow issue like temperatures trends in the most recent years.
>You know, what struck me about all the data
>presented in that article is that they include
>the anomolous data from approx '98, and nothing from before it.
Yes, you're right. That is a problem. Picking
different base years would affect the results.
But how much? Look at the charts again -- it
seems clear that the moderated warming/actual
cooling picks up in the last years. So, just
start in 1999, 2000, or 2001, and recompute the
numbers. I think the point would be essentially
the same, although the analysis would yield somewhat different numbers.
Although I don't have them at hand right now, I
know I have seen other analyses which definitely
and explicitly avoided starting at 1998. Googling around, I see this:
-- which argues that temperature trends *since
2001* fall well below IPCC projections. I
remember reading other reasonably credible
sources that agree with that, and others that disputed it.
One commentator says:
John V (Comment#1009) March 10th, 2008 at 8:53 pm
Hmmm, my numbers dont quite match yours. I hope
you dont mind a question or two to track down the discrepancies:
Using monthly data, I get the following global
trends from Jan 2001 to Feb 2008:
GISS: +0.83 C/century
HadC: -0.55 C/century
RSS: +0.41 C/century
UAH: -0.07 C/century
AVERAGE: +0.16 C/century
However, when I compute the trends from Jan 2002 to Feb 2008 I get:
GISS: -0.29 C/century
HadC: -1.67 C/century
RSS: -0.91 C/century
UAH: -1.71 C/century
AVERAGE: -1.14 C/century
I cannot evaluate those numbers, since I don't
know Cochrane-Orcutt. Anyway, as I said before
(and I think you agreed), these short-term trends
really don't tell us anything, so I'm going to
try not to spend more time on this particular
point. Actually, it's really quite annoying that
the author did use 1998 as a base year. That just
obscures the point that was to be made by opening
him (rightly) to cherry-picking charges.
It is clear to me that there are plenty of
analyses suggesting that warming has recently
been below trend that do NOT depend on starting with 1998. For example:
The following post seems quite interesting and
helpful. It explains why Lindzen's claim that
there has been no "statistically significant"
warming over the last 14 years (since 1995, not
1998, note) is "not wrong, per se, but neither are they particularly robust":
A Cherry-Picker's Guide to Temperature Trends (down, flateven up)
BTW, I notice that even Gavin at RealClimate
acknowledges that "(2) It is highly questionable
whether this pause is even real. It does show
up to some extent (no cooling, but reduced
10-year warming trend) in the Hadley Center data"
Again the GISS data gives a different result. (At
a quick look, I don't see him discuss the other
two datasets.) Of course RealClimate attacks the
analysis, then that attack is attacked...
There's more commentary on the disagreement here
(but, note, using only Hadley and GISS):
Among "lucia's" conclusions: "It does look like
both RC [RealClimate] and Lindzen are doing some
cherry picking of different sorts as suggested by Chip in his article."
I don't think you can rightly dismiss doubts
about claims of continued or accelerated recent
warming by looking only for those who start their
charts with 1998. I agree completely, however,
that it's right to criticize those who do so.
Sorry for wasting your time and mine on this
rather insignificant (but annoyingly nagging) issue.
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