Observational fact and direct experiment prove that your hypothesis is bogus.
What hypothesis would that be? Your posts are so disjointed and jump from topic to topic so erratically, you're going to have to be more specific. To keep it simple for you, CO2 and the other GHGs act like a blanket, keeping in more heat. It's easily demonstrated in a lab that they absorb IR and since statistically half would be re-emitted towards earth, the earth stays warmer. Add another blanket(more GHGs) and the atmosphere would retain even more heat than if they weren't present.
You keep saying blanket, blanket, as if that meant something. Do you have one of the new temporal thermometers for kids? The sort that you touch the child's skin with to read a surface temperature? If so, try this out. Take the temperature of your skin. Then put a blanket over your skin for a minute or so, then take the surface temperature of your skin. Do you know what you will see? The surface temperature of your skin will have dropped. Heat will have flowed from your skin to the blanket, exactly as the 2nd law of thermodynamics predicts. Putting a blanket over yourself actually cools your surface temperature.
As to downward emitted radiation, try the experiment I have provided with the parabolic dish. If IR were being emitted downward, you could not achieve a cooler temperature than the surrounding air by pointing a dish upwards at the downdwelling radiation. Do you have such a poor grasp of the science that you believe that downdwelling IR could actually warm the planet and promote cooling if one points a parabolic dish towards it? What laws of physics do you suppose predict such a thing?