In other words, CO2 causes absolutely no net change in energy, which is a necessary component of "global warming." In order for the atmospheric heat (energy) content to increase, CO2 would have to store energy, not absorb and release it almost instantaneously (via fluorescence).
You initial premise is faulty, i.e. a net change in energy being necessary. CO2 stores energy - as heat - that’s why it warms. There is no net change, only an energy transfer.