[marktwain]

They have not even quantified the amount of heat automobiles give off as they operate their internal combustion engines.

That is because the amount of heat from engines is insignificant.

The only way that they get significant warming is to claim that CO2 causes a little warming which then causes a type of cloud increase which triggers a feedback loop that results in significant warming.

All the "proof" is in computer models that cannot be validated, by their very nature.

[justa-hairyape]

Kinda hard to state something that has not been quantified is insignificant, when it has not even been quantified. Apparently the only reason CO2 is theoretically a problem is due to the increased water evaporation that occurs (feedback) due to the trapped heat from the CO2. So any generated heat effects get amplified by the resulting increased water evaporation. And urban areas are definitely sources of water vapor.