Well, to be exact, you should model any regular injection of heat as a perturbation in the heat influx, which, in the case of humanity's total energy usage, com

Well, to be exact, you should model any regular injection of heat as a perturbation in the heat influx, which, in the case of humanity's total energy usage, comes to about 0.1% of insolation -- and we'd generate the same amount (if not more) of heat by burning oil anyway!