Surely you mean, "....is constrained by the Second Law of Thermodynamics...."

E=mc^2 has nothing to do with the case. In fact, if we ever get Fusion working (which we almost certainly wont) then E=mc^2 will solve our energy problems.

Surely you mean, "....is constrained by the Second Law of Thermodynamics...."

We're depleting the capacity of the sky to act as a heat sink?

Yeah yeah he knows, it was just to get you out posting! Welcome :)