re: RealClimate.org
I check in there once in a while. I spent some time a while back looking at the various arguments on the CO2/temperature correlations for the last half million years or so, and so far, nobody to date seems to have nailed down which is cause and which is effect in these old readings.
There is some stuff on the release of CO2 from temperature rises creating a feedback effect that pushes the temperature higher, but nobody ever says why they should then drop back down again.