Bazz: "I originally thought the decline being talked about was the one from 1998 but it is clear now, especially as the emails are dated about 1999 or 2000, that they were on about matching the tree ring data to the thermometer data since 1960 and hiding a fall in the tree data."

Would you like me to explain the below in further detail?

<< The significance of the divergence is a “problem”, recognised as such by dendrochronologists themselves. The ‘decline’ hasn’t been ‘hidden’, as some people want to believe.

The reliability (of the method) is tested by omitting some of the instrumental data and seeing how the reconstruction matches the known climate at some past time (e.g. volcanic residue, micro-flora, isotopes, etc). I’m sure many people don’t understand this and perhaps take ‘hide the decline’ out of context – for various, nefarious, reasons.

Reconstructions can be tested against historical sources of climate information that go back centuries, and overall reliability is tested with different methodologies, and with different proxy choices (tree rings, corals, ice cores, ocean sediments, stalagmites, etc). If they vary widely, then proxy reconstructions wouldn’t be very reliable. However, if they are consistent (they are) then we can have confidence they’re robust. That’s why the so called “MBH hockey stick” isn’t crucial – there’s dozens of hockey sticks, from many different proxies and from many different sources, that all show the same thing – the warming trend is up. Ok, the methodology of any proxy reconstruction is complicated (I’m no expert) – but, the principles are not.

Obviously, uncertainties do increase the further you go back in time - and the ‘divergence problem’ for trees less than 50 yrs old is, well ... problematic. Agreed, further research must be carried out to explain the ‘divergence’ – but you don’t throw the baby out with the bath water. Much of the misinformation (intentional or otherwise) that surrounds this issue is because people mistake a reconstruction of the past with a present ‘attribution’ – and of course, that’s impossible. >>

You obviously still don't understand "hide the decline".

Cont'd

Sorry folks, pasted to wrong thread.