cc: iceage@ldeo.columbia.edu date: Thu, 25 Jan 2001 02:40:44 -0500 from: George Kukla subject: Northern trees to: Keith Briffa Dear Keith, You are the only guy who may know what was and is going on in the northern forests. 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! George