A propos of my earlier piece about the Hockey Stick, here's Keith Briffa's take on the "NAS defence", from Climategate email no 1140039406.
...you have to consider that since the [Third Assessment Report], there has been a lot of argument re [the] `hockey stick' and the real independence of the inputs to most subsequent analyses is minimal. True, there have been many different techniques used... but the efficacy of these is still far from established.