Two bodies in a vacuum. One radiates energy. The other is passive. When the passive body reflects as much as it absorbs, it remains at constant temperature. If its reflectance lowers, it must, must, must move to a higher temperature in order to achieve and maintain energy balance.
There are simply no other possibilities. Everything else is about the details of the process to restore balance.
Greenhouse gas concentration in our atmosphere have the affect of lowering our reflectance.
Pretty severely mangled, but better than the combative crap that I've seen on this thread so far..
My gosh folks -- its not that hard once you realize there are SEVERAL different text books required here. The laws of EM propagation have NOTHING to do with laws of Thermodynamics.
EM energy in the form of light or IR or UV CAN AND DO propagate from cooler to hotter objects.
I can't imagine why Polar and SSDD want to deny the role of GHGases in warming the planet. And I abhor your inference that religious people can't comprehend or practice science.
It's actually quite simple and most of the errors I've seen here is because of the confusion between EM radiation and heating. They follow different rules. And YOU are only partly right about CO2 "lowering our reflectance". It is not a great reflector reflector of the INCIDENT sunlight which comes into the surface in a broad band of wavelengths, but it does ABSORB the longer wave IR radiation that is generated by the Black Body effect of the earth's surface. Not as good as dominating water vapor, and it does saturate in its ability to convert long wave IR to heat, but nonetheless,
this conversion of long wave to heat in the troposphere DOES heat the troposphere. EVEN IF the troposphere is cooler than the surface.
I could heat hamburgers with IR thru a vacuum tube with no Thermodynamics involved in the transfer. Just as the Sun heats the earth thru the cold vacuum of space. Furthermore, I COULD lower the emitter temperature of the IR heater to near Zero and still use it efficiently to heat burgers at a distance. You are just spoiled because most EM emitters "self-heat" and end up being quite hot because of the materials involved and the inefficiencies of converting electrical power in EM radiation.. But it's not REQUIRED that an EM emission source be "warmer than the impinged surface" in order to contribute to thermal energy in that material.. No science at all says that...
I could blast nitrogen with long wave IR all night long and not raise it's temperature. But because of the absorption bands in GHGases, it will HEAT if radiated at the earth's Black Body frequencies. That's the GreenHouse. It's NOT a material like glass that's preventing convection or conduction heating. That's a disservice in the naming of the effect. It's a change in the THERMAL RESISTANCE of that thin layer of atmosphere caused by the mater4ial composition of that layer.
All the rest you need to know comes from the Thermo book which defines that the AMOUNT of heat energy flow is proportional to the Temp diffs between the surfaces. If you raise a thermal barrier ANYWHERE in the trop. , then the heat transfer to space will slow down the THERMAL energy flow towards space. ((Thus the confusion about detecting a cooler or warmer Stratosphere in the presence of warming. It's not clear that a couple degree barrier in the Trop will have a distinct and detectable fingerprint farther up because its too small and the heat paths and mixing are too complex))
That's it.. and there are good and valid reasons to discount the hysteria about CO2 forced heating of the earth surface. But in THEORY, and in real life, it DOES what the "GreenHouse" theory says it does. Only not as a prime driver of the climate as the wacky believers declare...
THIMK a little about the diff between your Field and Wave class and your Thermo class and then we'll all be on a better track here..
Educating them on why the temperature chart looks like it does is very important within context is where we're lacking. Only then can we bring up the bads of this positive. 
