Fact is, if we keep adding waste heat created from some stored energy, be it fossil, fission or fusion, to the environment, net temperature of the earth has to

Fact is, if we keep adding waste heat created from some stored energy, be it fossil, fission or fusion, to the environment, net temperature of the earth has to rise to get rid of said waste heat via additional radiation into space. The cheaper that energy is the more the temperature will rise. In that sense, the only "clean" energy sources are what is radiated in from the sun and what is conducted out from the core.