The problem I have with the article is that it confuses two separate debates, one scientific (is climate change real?) and one value-based (what should we do about it?). By putting these two issues into the blender, the article confuses rather than clarifies.So what's the real middle in climate science, in terms of actual science? My amateur outsider's perspective is that there are two respectable scientific camps. In one camp we have people like Kevin Vranes and James Annan, and maybe we can broaden it somewhat to include William Connolley. These people think the mid-range IPCC climate projections are credible (or maybe for some the low range is credible), and the high range or above projections aren't credible. Separate from the science, they think the clear policy direction from this scientific understanding requires cuts in greenhouse gas emissions. (Let's see how many comments I get on how badly I've bungled their positions). (UPDATE: per comments, I removed Pielke Jr. from this group.) (UPDATE 2: See Connolley's comments re himself and Annan - my argument may be falling apart, but I'm not convinced yet.)
The other camp has people like Stephen Schneider, James Hansen, Eli Rabett, and non-scientists like Nicholas Stern, Al Gore, and inconsequential backseat-driving bloggers. This camp believes that the high-end climate projections are possible, or they think that because the unaccounted-for effect of each of the "known unknowns" ranges from neutral to bad, then high end or worse projections are credible. Separate from the science, these people think that the risks from the worse climate scenarios should also influence current policy direction on how to reduce emissions.
I suppose one could argue there's a middle ground for people who give a very low but real possibility for the high end projections to happen. I don't think that's the case though when it comes time to apply the science to policy - even a small chance of these very bad scenarios occurring should significantly affect policy.
Figuring out whether the high-end scenarios are possible should drive the discussion of the status of the middle ground and which side seems likely to be right, not some muddled middle of techno-optimists and near-denialists. I don't think they're relevant to the scientific debate, nor is James Lovelock or anyone off the deep end on the alarmist side, as well.
UPDATE: I agree with the blogosphere that Michael Tobis' comment on the problem being multidimensional rather than Revkin's linear setup is an excellent way to understand it. Maybe better than my approach. Someone with good graphics capability could even set up a website with rotating dimensions to show this multi-dimensional question.
Different point: I may have been trying what Eli describes as Overton framing, "a method for moving that window, thereby including previously excluded ideas, while excluding previously acceptable ideas." Whether I got it right is debatable, I suppose. See Eli for his approach.