In para. 7 he refers to tree ring data. This has a close relationship to temperature, except in the later years of a tree's life, when rings are stretched thinner, and therefore produce a false impression of colder climate. Dendrochronologists therefore have to make an adjustment to the data to allow for this fact.
McIntyre however states in his paper, "there was no scientific basis for such an arbitrary adjustment". (para. 8).
I wrote a polite question on his blog discussion thread asking him about this point.
Steve, you say “there was no scientific basis for such an arbitrary adjustment” [of the tree ring record], my understanding is that it is a feature of dendrochronology that more recently laid down tree rings are thinner than those buried more deeply within the tree. Which would create a scientific basis for applying an adjustment. Would it not?
Steve: Not this adjustment.
So it seems that McIntyre is wrong about tree rings. The charitable interpretation is that he does not understand. But he should do, because he has been banging on about it for years and years.
Now, then, let's get into Daily Express mode: [CAUTION: IRONY WARNING!!]
CLIMATE CHANGE SCEPTIC MAKES ERROR SHOCK
Canadian engineer Steve McIntyre, the self-styled "scientist" at the heart of the vicious attack on the future of the planet, has an error of science right at the heart of his submission to respected Science and Technology Parliamentary Committee. He does not understand the basic facts of tree ring data. This latest revelation totally invalidates the case of climate skeptics, and proves that ...
[IRONY WARNING ALL-CLEAR]
Sorry, I can't keep it up. But this is indeed a cameo of what is happening. The sceptics take a single error, inflate it into a general refutation of the whole picture, weak-minded and gullible journalists take it up, and the grasp of the public on what is going on is further diminished.
Goebbles must be giggling in his grave.
Here is a detailed answer to McIntyre by Briffa on this question.