date: Thu, 25 Jan 2001 02:40:44 -0500
from: George Kukla <kuklaatXYZxyzo.columbia.edu>
subject: Northern trees
to: Keith Briffa <k.briffaatXYZxyz.ac.uk>
You are the only guy who may know what was and is going on in the
With respect to that I do not think that the WMO statement # 913 on
the status of the global climate in 1999 is a sufficiently reliable last
word. For one thing: the curve attributed to you doesn't seem to jive with
any of the figures of your 2000 QSR paper. Where from did they get the
0.6 degree departure at 1600 AD? Another problem: the ring density and
width in the last several decades are both decreasing which at any other
time would be interpretted as a sign of cooling. So why is it shown in the
WMO report as an unprecedented warming?
As you properly discuss in your papers we just do not know how
exactly do the tree rings relate to weather. In my understanding we are
left with the following options:
1) The calibrations of the rings to temperature prior to 1950 are biased,
possibly due to the poor coverage of temperature stations.
2) Something other than the temperature influenced the trees in the last
several decades and we do not know what.
In either case it is not very responsible to relate the curves to
global climate as WMO has done. You are saying it, albeit somehow
indirectly but pretty clearly, in all your papers. Unfortunately it
appears that these are tooo long for WMO to read.
Ciao and greetings to everyone down there!