There's also some newer work on latent heat in the Earth's mantel and core. There are geophysical cycles where more mantel is melting than solidifying, which releases latent heat to the surface.

Solar activity, ‘milankovitch’ cycles have a big effect on temperatures. I’ve heard Solar scientists call out the nonsense that CO2 is driving temperatures. CO2 change is a down stream effect of temperature change as you say. 

cristaiji

Bell_curve

They do correlate pretty strongly, but the temporal lag indicates that it's actual rising temperatures that increase CO2 levels, rather than the opposite. That's likely because warmer water retains less dissolved CO2.

Undisciplined

econ

How The EU Creates The Welfare Entrepreneur

TomK

I'm no meteorologist or chemist, but how these freaks in Davos managed to correlate the climate and temperature fluctuations of the planet with man-made CO2 emissions is still a media mystery to me today