Steel Greenhouses and General Electric Lightbulbs
What is heating…
The “steel greenhouse” provides a basic schematic for the meme of the atmospheric greenhouse effect, among other sources. Sometimes the terminology goes by the phraseology of “backradiation”, and sometimes it goes by that of “heat trapping” or “heat flow restriction”, and others, as the need arises. There is little consistency, and these terms can all mean very different things physically, which is curious for a supposedly scientific concept.
Generally, the underlying concept is that a heat source which is enclosed in some relevant fashion will “become” warmer because, variously, A) radiation from the source of thermal radiation directed back to the source of radiation (i.e. backradiation) by the enclosure leads to the source becoming warmer, because i) radiation from the cooler passive enclosure, either reflected or absorbed and re-emitted from the passive enclosure and back to the warmer source, becomes thermally absorbed by the surface of the warmer source which leads to the warmer source becoming warmer still, or ii) heat trapped by the enclosure leads to the source of heat inside the enclosure to become warmer as the source struggles to radiatively emit the same amount of thermal energy to the outside of the passive enclosure, or B) as the source of heat warms the cooler enclosure, the source of heat is lead to become warmer still as the cooler enclosure warms up to equilibrium with the source of heat, in order to maintain the temperature difference between the source and the passive cooler enclosure.
Applied to the atmosphere, the terminologies are such that the atmosphere heats the surface of the Earth with backradiation, or that the atmosphere traps heat from the surface thus leading to the surface becoming warmer in the attempt to cool, etc. It is the presence of a cooler object, i.e. cold atmospheric gas, that by some method, leads to the source of heat of the cooler gas, which is the ground surface, to become warmer.
None of these statements are physically valid or are supported by traditional or modern physics.
Let it be clear, the only physically valid statement that could be made is that:
The atmosphere becomes warmer, if it absorbs more heat.
The surface becomes warmer, if it absorbs more heat.
I will let Pierre Latour speak here, from a private email discussion:
“The Stefan-Boltzmann equation gives intensity of radiation, W/m2, emitted by a body at temperature T. It is analogous to fluid pressure, kg/m2. Stefan and Boltzmann called it intensity, not heat transfer, because it is intensity, not heat transfer. (It becomes heat transfer in maximum case emitting to 0K surroundings, so it is a max heat transfer. Real transfer is always less.) All bodies radiate with an intensity and they all experience a pressure. But for a fluid to flow there must be a driving force, a pressure difference. Physics teaches the fluid flows from high pressure to lower at a rate proportional to the pressure difference. The pressure at the bottom of the sea is high but uniform so no fluid flow.
For radiant energy to flow, transfer from one body to be absorbed by another body, heating it, there must be a driving force and that force for radiant energy transfer is an intensity difference. Physics teaches that the radiant heat flows from high intensity, to lower intensity, at a rate proportional to the difference (TH4 – TL4). Two identical glowing radiators facing each other radiate intensely but without any heat transfer between them.
The GHGT error is assigning to that second intensity term in the radiant heat transfer law an energy flow from cold to hot. Just because there is an algebraic term in the equation for cooler body radiating intensity does not mean it corresponds to a rate of heat transfer from cold to hot.
Atmospheric CO2 radiates with same intensity in all directions but the direction and rate of heat transfer to surroundings depends on surrounding’s radiating intensity. Energy transfer is asymmetric. So if the K-T 333 back-radiation arrow signifies direction of downward radiation intensity in all directions, ok, if they point it in all directions. But K-T labeled their diagram energy flows, and their back-radiation arrow 333 cannot be a flow, absorbed by surface, warming it further. Hence we have the dispute about semantics of physics which GHE believers dismiss with derision. “
If the atmosphere gets warmer by absorbing more heat, then something already warmer than the atmosphere (particularly its own source of heat, the surface) doesn’t need to become warmer-still in this process. The atmosphere is simply heated to higher temperature by something warmer than it, up to the point where they’d be equal in temperature. And that’s it.