The headline was prompted by JF's tribalism: Frankie, anyone? Incidentally, translations of the cryptic references are available on request, if you find them too cryptic.
To understand this (if you really want to) you need to read http://climatesci.atmos.colostate.edu/?p=36#comments by RP; and JF's post ref'd above. Note, BTW, that RP has removed some of the comments from his blog (even James Annan gets rubbed out, along with the wackos), which explains why the comments refer to comments that don't exist and why the numbering is all wrong. Argh!
So: JF complains that I'm being too tribal in being interested in an answer to the question do you think most of the warming observed over the last 50 years is attributable to human activities?. It seems a fair enough question to me. And presumably to RP too, since he answered it "I do". I asked it because I thought his previous answers were ambiguous (and in the end the question turns out to be ambiguous too: see lower down). And other people thought so too, because several people commented on his blog (sadly those comments now seem to have been deleted) that the question I asked was unreasonable; or that RP had said the answer was no (I wish the comments were there so I could quote them rather than rely on memory). Those comments weere of course proved quite wrong, when RP *did* answer the question. And I'm reminded of a wise comment by James Annan, with ref to a post where RP Jr made it quite obvious that he accepts the IPCC consensus, that its very amusing to see the pain ond outrage on the part of the septic ditto-heads when they see such unambiguous statements, because they really thought that RP Jr was on their side. Now that simply isn't possible without some dense and/or ambiguous language (the septics are dumb, yes, but not totally so).
Now for myself, I'm quite happy to accept the IPCC consensus position (slightly updated with post-TAR research, e.g. the most recent MSU stuff) and don't feel any need to have my own position. RP Sr *does* have his own position, and... well, read his blog to find out what it is: thats part of what its for. Starting here perhaps... I got a bit lost in the maze of responses to Andy Revkin. RPs Sr's position is in fact at variance with the IPCC one, because although he agrees on the human influence (see above) he doesn't agree on the cause: which shows that far from questioning too much, I stopped too soon: because Is most of the observed warming over the last 50 years likely to have been due to the increase in greenhouse gas concentrations gets a far more nuanced response from him. Since I agree with the IPCC response, I disagree with RP Sr's nuances, and would simply answer the question with "yes".