I have an article up at the Spectator's Coffee House blog on that awful dilemma for the IPCC:
It will not be an easy task. However the IPCC chooses to deal with the problem the repercussions are unpleasant. They might try to explain away the warming hiatus in some way: the in-vogue explanation is that the heat that should have been in the atmosphere has escaped, undetected, to the deep oceans. Evidence to support this idea is, however, scant at best, and going down this route is going to involve the IPCC admitting that there is much about the climate system that is not yet understood. This will be a hard act to carry off while simultaneously claiming that they are certain that mankind caused most of the recent warming.