The process for developing the next IPCC report is well underway. The WG1 zero-order draft of the 5th Assessment Report (AR5) report is basically a scoping document in which the authors flag the approach and expected content of the final report. The 'ZOD' was reviewed by nominated expert reviewers and the comments and next steps would have been discussed at the July 2nd IPCC authors meeting. On past performance, the contents of the ZOD will have nothing much to do with the final report (which is 3 versions, two rounds of expert review and government review away).
A recent round of FOI requests in the UK (for instance, here) has asked for all of the ZOD material (along with all comments and names of reviewers) from all UK bodies whose employees participated in the Brest meeting.
US FOIA provides a specific exemption for drafts or predecisional materials, and in the UK law, similar protections exists for material that is in the course of completion or unfinished documents (Section 12(4)d).
Additionally, since the IPCC intends to archive drafts and reviews, section 22 "information slated for future publication", might also hold. However, since IPCC is an international body, headquartered in Switzerland (with no FOI legislation), it is unclear that this is relevant.
The point of these exceptions is to allow public bodies to be able to complete a draft and review process of complex documents without having every step scrutinised and potentially interfered with. An argument could be made that the ZOD is in itself a completed report and thus ineligible for the exemptions listed, but precedents (at least in the US) suggest that reports that are called 'drafts' are indeed 'drafts' and not final reports.
Multiple requests to multiple bodies for the same information (as in this case) certainly increases the chances of inconsistent responses and this is likely to be repeated at every step of the AR5 report's drafting process. Since the reasons for release or not should be the same for each body (though the requestor is clearly hoping for some variation), this seems a little like FOI spam.
Issues: drafts, predecisional information