Hans von Storch has posted up a letter from Martin Parry, the largely silent former-chair of IPCC AR4 WGII, to WGII authors on the various errors and sloppiness found in the report that he led. In short, Parry finds that there is not much wrong in the report:
Firstly, in the current clamour it is easy to forget the big picture, which I think is this: That the WG2 volume represents a sound and reliable statement of our knowledge, and is the product of robust and rigorous assessment by you all.
To see how misleading this statement is, one need only look at Parry's dismissal of complaints about how the the issue of disaster losses was handled in the report:
IPCC authors have defended their statement in Chapter 1 that one study indicates an increase in economic losses due to disasters after normalizing for wealth and property while other studies do not. This rebuttal can also be found on the IPCC home page.
This statement, as readers here will know is highly misleading. Prior to Parry writing this letter,
IPCC Lead Author Robert Muir-Wood explained that he thought that the IPCC should not have included a misleading graph showing a relationship between rising temperatures and disaster losses. One hopes that the attitude displayed by Parry reflects the IPCC of the past and not its future.