Comment by ben_w

Yes, and?

The same is the case with the Dyson swarm. Space goes from being empty to partially re-emitting as a warm object in our direction.

The joule heating from current human power is negligible; conversely, a 4% partial Dyson swarm directly heating the earth (i.e. not just greenhousing Sol) wouldn't be just +3 K change in equilibrium, it would be something like +24,400 K, which would vapourise and gravitationally unbind the planet.