* It is not possible to trap heat.
* It is not possible to trap thermal energy. There is always heat.
* It is not possible to trap light (Planck's law).
* You cannot warm a rock with a blanket (1st law of thermodynamics).
* You cannot create energy out of nothing (1st law of thermodynamics). No gas or vapor is energy.
* You cannot use a colder gas to heat a warmer surface (2nd law of thermodynamics). Heat only flows from hot to cold, NEVER the reverse.
* You cannot reduce the radiance of Earth by trapping IR light, and increase the temperature of Earth at the same time (Stefan-Boltzmann law).
Define 'real'.
No gas or vapor is capable of warming the Earth using IR emitted from the Earth's surface.
Emitting light requires energy. The surface is cooled by emitting light. Absorption of IR by CO2 does not warm the Earth. It's just another way for the surface to heat the atmosphere (and be cooled in the process).