[ale] [OT] Psychology of Denial about Climate Change

[Greg Freemyer]

On Mon, Dec 14, 2009 at 11:21 AM, Doug McNash <dmcnash at charter.net> wrote:
> Jim,
>
> I thought you declared and end to this?
> Nevertheless I will still play as long as there is no objection from the list.
> ALE has a long tradition of OT threads, most of which I have found educational and amusing in the past.
>
> So far as far as I have been able determine, the only provable fraud has been been with the handling of the Briffa tree ring data.  The tree ring measurements are used as a proxy for temperature for the recent period before the invention of the thermometer.  But this proxy shows a decrease in global temperature since 1960.


As I understand it, the issue is more complex than that and I don't
think it rises to the level of "fraud".

The tree ring analysis from Briffa in the early 90's originally
apparently matched the temp record from 1850-1990 fairly well, but it
also showed the temps being even higher during the MWP than during the
1990's.

(MWP - Medieval Warming Period about 1000 years ago.  When Greenland
was actively being farmed, etc.)

Apparently the emails show a discussion led by Dr. Jones that
temperatures being that high during the MWP is in disagreement with
either other data, or with CRU preconceived ideas.

(The emails I have read are not clear on why Dr. Jones felt the MWP
was cooler than today, just that the MWP being warmer than today
seemed wrong to Dr. Jones.)

Apparently based on Dr. Jones feedback Briffa went back and adjusted
the tree ring analysis process to get the MWP era into what Dr. Jones
felt was a more appropriate temp range.

(That may have been perfectly reasonable if other trusted temperature
proxies showed the MWP to be cooler than today.  More investigation
into why the tree ring analysis was modified will surely be
forthcoming as climategate proceeds.).

The scientific issue was that after Briffa modified the process for
interpreting tree rings to "properly" address the MWP, it caused a
divergence in the post 1960 temps.

The solution the CRU came up with 10+ years ago was to simply drop the
tree ring analysis at 1960 and graft on land based thermometer based
temperatures.  The end result was the infamous hockey stick of
temperatures covering the last 1000 years that was published in 1998
or so.  That hockey stick chart has been widely used/referenced and
was part of the IPCC report in the early 2000's.

OTOH, It was dropped from the 2007 summary report.  I believe because
further analysis showed the modified Briffa series was not as accurate
as it was originally believed to be.

Specifically if you look at the "IPCC, 2007: Summary for Policymakers"
report <http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf>
you can see that a chart showing temps for the last 1000 years is
simply no longer provided.

I assume that leads most readers (politicians) to assume the old
hockey stick is still valid.

Greg