thanks for responding.Ian, sorry for the delay getting to your post. Do you believe that back radiation is absorbed by the surface?I totally agree with W's question.
Until those who deny backradiation can come up with an explanation using physics to account for surface temperature being all out of proportion to solar input, then the discussion is useless. And make no mistake, the difference is huge, it is not some small quibble over measuring surface temps or solar input. It is 15C difference, more than enough to turn the Earth into a frozen ice cube.
And do you believe back radiation is heat?
I have gone into great depth answering this question on numerous occasions. Do you hope that my answer will change?
Of course radiation from the atmosphere is absorbed by the surface. Where else would it go?
Heat is a property of macroscopic quantities. Warmer matter produces more radiation than cooler matter, hence the overall net transfer of energy is always warmer to cooler.
On the microscopic level, radiation just is. One molecule doesn't have a 'temperature'. Only large groups of molecules have an average kinetic energy which considered it's temperature.
Molecules in close proximity collide with each other, producing blackbody radiation proportional to its temperature.
The blackbody radiation from the surface either escapes to space, or is absorbed by the atmosphere, which warms the atmosphere. The warmer atmosphere produces blackbody radiation which either escapes to space, is reabsorbed by the atmosphere, or reaches the surface where it is absorbed.
The equilibrium temperature of the surface is defined by energy input minus energy output. Radiation is part of that equation. While the atmosphere is cooler than the surface, it is much warmer than empty space, therefore it 'gives back' some of the radiation it receives, which keeps the surface warmer than if there were no atmosphere.
Reality is obviously more complex. There are massive heatsinks that are filled with unimaginable energy, eg liquid flowing oceans and gaseous flowing atmosphere.
I don't expect you will understand all this this time because you have failed in the past. But I wish you would try.
First, the atmosphere is cooler than the surface, it has been and always will be based on sunlight and the fact the surface absorbs the sun's energy. the earth then radiates what it absorbs back up to the atmosphere, LWIR and that has heat. i.e., When I heat a frying pan on the stove top and turn off the heat source, the pan will radiate heat for some time. It will begin near a constant it was at with the flame and then slowly cool off. The air above the pan does not re-radiate back to the pan to keep it hot, nor does the air make it hot once it cools off. BTW, I know you know I will never believe that occurs. The reason, there just isn't evidence of it occurring, cooler air cannot warm anything warmer than itself. Feel free to post up an experiment that shows me wrong.
As for your back radiation, if there was indeed back radiation, you claim it comes from CO2. Are you sure? Do you have that evidence as well? Come on, you've been following my posts over the years now, you know I have my expectations and to today, there has not been one iota of evidence ever presented that shows the magic power of CO2 gas. I truly wish to see it, cause it sounds way too magical for me.
I have observed clouds at night keep the ground below warmer than if the clouds weren't there in the winter. I've experienced it, I've felt the difference. When the ground is cooler than the cloud the cloud radiates to the surface, it's always been in winter months again when the surface air is cooler than the clouds.
I believe in the bright yellow ball in the sky and its power to heat. I also observe the surface of the earth heats up from that source. I also can see the heat radiating upward off of surfaces such as asphalt and cars. yep, I can see it radiate and it is always moving ground up never air down. I also know that the surface can be hotter than the rays hitting my own skin, so indeed the surface material gets very hot, enough to fry an egg.
You have asked me before why I don't believe in back radiation, and my answer is that I don't see it, nor has anyone ever proved it. you've also asked me if I think molecules radiate and I've said yes. Warm to cool is the direction only. I can't help that I believe that, the fact is there isn't evidence and for two years now, no one has presented it.
As always, you fail to understand the simplest concepts. Please don't ask me to explain in the future.
I will point out one strawman in your post. You say that I claim that backradiation comes from CO2, no quote of my actual words of course.
I claim that backradiation is predominantly produced by blackbody radiation from molecular collisions. Which is proportional to temperature.
How does extra CO2 increase atmospheric temperature? All the energy in certain bands of surface radiation is absorbed to extinction by about 10 metres. Adding more CO2 reduces the 10 metre extinction height. By simple math that anyone can comprehend, the same energy added to a smaller volume of gas will cause an increase in temperature. QED.