re: Not that far out of the box
you have a layer of another substance that's excited by infrared and reradiates at shorter wavelengths
Conservation of energy is the problem with that idea- you are essentially wanting something that absorbs a low energy photon and radiates a higher energy photon...
Or--hey, RL, could you make a concentric shell of gas lase?
I am not sure what you are getting at here...
The only ways I can think of to diminish the greenhouse effect are 1) reduce the solar flux, 2) devise a way of removing green house gasses from the atmosphere at a HUGE rate or 3) Get our act together and drastically reduce our production of such gasses.