Gate Du Jour: IPCC AR4 references NYT story

Ed Begley? Care to comment?

19 hours without electricity. Oh the humanity!
I recall five days melting in the dark after Hurricane Rita. No computer, and I knew only one tune on the piano.

Gate de Jour submission for next time. It’s not a competition, I simply don’t know where to post it.
Palaeogate.
From the CRU emails:
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9/14/98 -0700, Jonathan T. Overpeck wrote:
>Hi Phil et al. – just read the Jones et al. Holocene paper (v. 8, p.
>456-471) and had a couple comments/questions….
Has anyone examined how a tree-ring recon degrades as a function of sample size back in time. I always see the quality of dendro recons cast as GREAT vs.other proxies (and they are) based on comparison with instrumental records. But, the dendro
records usually have the best sample replication in this same instrumental period, and then tail off back in time. For example, Brian’s Jasper recon has a sample depth of ca 28 trees in the last century, but drops off to ca. 5 in the 12th century and 1 (?) in the 11th century. The “quality” of the recon must degrade too?? In contrast, some non-dendro reconstructions may not verify as well as dendro vs the instrumental record, but they might not
degrade with time either since the sample density doesn’t change with time.
Thus, could it be that at some point back in time, the dendro records degrade to the same quality (or worse) than other proxies???
5) Talking specifically about Jasper, it is interesting that the 20th
century is as warm or warmer than everything in the last 1000 years EXCEPT before ca. 1110 AD. Since the sample depth before this time is 5 or less, how much faith should we put in those warmer than modern temps??
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Then we have
From: “Raymond S. Bradley”
To: Frank Oldfield
Subject: Re: the ghost of futures past
Date: Mon, 10 Jul 2000 08:57:19 -0400
Cc: alverson@xxxxxxxxx.xxx, jto@u.arizona.edu, k.briffa@xxxxxxxxx.xxx, mhughes@xxxxxxxxx.xxx, pedersen@xxxxxxxxx.xxx, whitlock@xxxxxxxxx.xxx, mann@xxxxxxxxx.xxx
But there are real questions to be asked of the paleo
reconstruction. First, I should point out that we calibrated versus
1902-1980, then “verified” the approach using an independent data set for 1854-1901. The results were good, giving me confidence that if we had a comparable proxy data set for post-1980 (we don’t!) our proxy-based reconstruction would capture that period well. Unfortunately, the proxy network we used has not been updated, and furthermore there are many/some/
tree ring sites where there has been a “decoupling” between the long-term relationship between climate and tree growth, so that things fall apart in recent decades….this makes it very difficult to demonstrate what I just claimed. We can only call on evidence from many other proxies for “unprecedented” states in recent years (e.g. glaciers, isotopes in tropical ice etc..).
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Comment by me:
Given that this was known in 2000, how does one account for the dominance of dendrothermometry in the material forming the backbone of the 2007 IPCC report, with its 90% confidence that rising temperatures were from man-made causes? Further, how can a hockey stick be justified to have a flat and level handle?
The “divergence” problem was known then, but it had disappeared from the agenda between 2000 and the 2005-7 period when papers were written for the 2007 IPCC. There was then and is not now, an explanation for the breakdown of proxies or the divergence post-1980 that makes calibration of dendrothermometery so incomplete and questionable.
If you take out dendro work and put proper uncertainties around other proxies, there is just no way to conclude that there were or were not hotter periods a thousand years ago, apart from the preserved written records and direct observations. So is there global warming, yes or no?
Even by 2005, some experts were still saying that the older record was not settled.
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From: Jonathan Overpeck
To: k.briffa@xxxxxxxxx.xxx
Subject: Fwd: Re: [Wg1-ar4-ch06] IPCC last 2000 years data
Date: Tue, 4 Jan 2005 21:52:47 -0700
Cc: Eystein Jansen , cddhr@xxxxxxxxx.xxx
The biggest problem with what appears here is in the handling of the greater variability found in some reconstructions, and the whole discussion of the ‘hockey stick’.
The tone is defensive, and worse, it both minimizes and avoids the problems. We should clearly say (e.g., page 12 middle paragraph) that there are substantial uncertainties that remain concerning the degree of variability – warming prior to 12K BP, and cooling during the LIA, due primarily to the use of paleo-indicators of uncertain applicability, and the lack of global (especially tropical) data. Attempting to avoid such statements will just cause more problems.
In addition, some of the comments are probably wrong – the warm-season bias (p.12) should if anything produce less variability, since warm seasons (at least in GCMs) feature smaller climate changes than cold seasons. The discussion of uncertainties in tree ring reconstructions should be direct, not referred to other references – it’s important for this document. How the long-term growth is factored in/out should be mentioned as a prime problem. The lack of tropical data – a few corals prior to 1700 – has got to be discussed.
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In summary, a neutral observer could say there is global warming if you believe group A of scientists and questionable global warming if you believe Group B. In the end, group A shouts down group B.
This is not an acceptable scientific basis for the hypothesis of recent global warming. Warmer than what?

“Mike McMillan (01:03:06) :
19 hours without electricity. Oh the humanity!
I recall five days melting in the dark after Hurricane Rita. No computer, and I knew only one tune on the piano.”
I recall the ’70’s in the UK. We had weeks of rolling blackouts due to strikes, which eventually lead to the “Winter of Discontent”, and then Thatcher.
Now that is a power outage, man made of course. All before AGW scare, but all within the next ice age scare.
Thank crunchie for age old carbon storage devices (Coal and wood).