Curry talks to an IPCC insider, who describes "a constant struggle between the newcomers, who want to ‘tell it like it is,’ versus the old hands who are worried primarily about what was said in the AR4 and not providing fodder for the skeptics"

Laframboise’s new book on the IPCC | Climate Etc.

...I ran into another of these [IPCC] individuals at the AGU meeting last fall, who had become jaded by the process. He said it is a constant struggle between the newcomers, who want to ‘tell it like it is,’ versus the old hands who are worried primarily about what was said in the AR4 and not providing fodder for the skeptics. Even if the ‘good guys’ prevail at the chapter level, I have the sad suspicion that the people who are really in charge will be playing politics with the document whereby primary concerns are not providing fodder for skeptics and showing continued increasing ‘confidence’.

The IPCC has clearly been playing egregious politics with climate science, as Laframboise extensively documents. Perhaps this is what the policy makers want, this whole thing is so politicized it is difficult to tell. But there is no escaping that the IPCC has severely tarnished its ‘brand’, since the heady days in 2007 with the release of the AR4 and the Nobel Peace Price: Climategate, Pachauri’s shenanagins, the explicit green advocacy by IPCC grand poobahs and their irrepressible urge to make imperative policy proclamations, and failure to address the reforms recommended by the IAC.

As a result, the IPCC’s legitimacy and authority in terms of its expertise and process have been diminished since 2007. Does this in itself mean that the conclusions in the IPCC AR5 are erroneous or otherwise inappropriate? Of course not. But it does mean that the IPCC will have to do a much better job in terms of making its arguments and defending its judgments than it did in the AR4, in order for them to be accepted. ‘Trust us – we’re the experts’ doesn’t play very well anymore with this particular group of experts.

Laframboise’s statement:
     Could we switch to the grownup channel, please?
pretty much sums up the whole IPCC situation for me.