Have they really bothered to ask the right questions?

"on balance the evidence indicates it's more likely than not that humans burning carbon are the dominant cause"

Might not the surface temperature record maybe... just maybe be influenced a teency weency bit by the oh I don't know, 66,000 square miles (roughly the state of Wisconsin in the US) of asphalt and concrete (primarily in the form of roads and parking lots) we've laid primarily 1950-on?

just a little?

At its core the attribution to CO2 is an "argumentum ad ignorantiam" - i.e. "[we can't think of anything else causing it so it *must* all (more or less) be GHG]". It's also why they have to rely on the GCMs to make their case - there is no simple equation to properly establish the mechanism.

Now, that's not to say that it's wrong, and as I've said before many times the science does imply that increased GHG concentrations *should* - all things being equal - result in increased equilibrium temperature... but that's different than saying we know the sensitivity of equilibrium temps to GHG concentrations and X implies Y with any real certainty... and as a student of economics no I do not place any authoritative trust in what the GCM's have to say about it because I've worked with economic modeling before and there are more similarities between the two than anyone on the hand waving side will ever admit.

Disagree if you want... I won't talk down to you for it. Beers all around, I see no reason for us (in general, all the commenters in this thread) to be so worked up about this. There are rational, intelligent, and well meaning people who both fully and much-less-fully believe in the consensus opinion... and yes, that includes people who think the actual anthropogenic GHG contribution to temperature just *might* be noise in the grand scheme of things.

Cheers!