"Because the stakes about climate change are high, science must recognise that the process whereby knowledge is created must be open to public scrutiny and engagement. And since policy decisions about climate change are being made now, and being made continuously, the ways in which knowledge is condensed, packaged and brought into social discourse also need to be re-thought."Bingo.
-- Mike Hulme, Why We Disagree About Climate Change (2009), Ch. 3
What harm does the IPCC see if the public does read the ZODs and, say, later notices that the final version of the Fifth Assessment Report is different? That it lacks some kind of consensus? That someone will have to explain why the change was made? What would be wrong with that, anyway? Isn't it an opportunity to explain the process and the evidence and the thinking? Is that a terrible thing? The IPCC seems to think so. I don't.
Their apparent notion that the 5AR is just going to be handed down as if from on-high, written in stone, and all the world's technocrats can work off that is troubling. Imperious. Arrogant. Yes, there are people who would use any such changes for less than admirable (IMO) purposes. But they will do it anyway with some other aspects of the report or process, and already have in the past. That's the way things things are. That's life. Invoking secrecy to try to combat that, which the notices seems to be, just compounds the problem.
UPDATE: It seems Steve McIntyre hasn't yet come to any decision about his IPCC notice.