ADreamOfLiberty said:
Daylight63 said:
2. CO2 and other greenhouse gases make up a small part of the atmosphere but are the reason the surface of the earth is about 30degC hotter than if there were no greenhouse gases in the atmosphere.
This is not known for certain.
The atmosphere cannot be discarded, even if it was transparent to relevant bands of thermal radiation.
Yeah it is. It's physics. The majority of the gases in the atmosphere (O2 and N2) do NOT absorb IR in any significant fashion. That's because those are diatomic molecules that have NO DIPOLE MOMENT, and as such don't really have any IR-absorptive bands. IR absorbs because of the BONDS between elements in the molecule. SInce O2 is O=O and N2 is N
=N so they don't really have any ability to absorb.
That would mean that incoming short-wave radiation (most of what comes from the sun to us) is absorbed by the solid earth and re-radiated out back as "downshifted" photons in the IR range (lower energy because they are longer wavelengths. The IR photons could then easily re-escape back out into the atmosphere leaving the surface at effectively the blackbody radiation temperature which trurns out to be calculable by Stefan-Boltzman and is about 30degC lower than our actual surface temperature.
It could, but it would not because the atmosphere itself emits thermal (blackbody, although that is the ideal case) radiation.
Therefore even with IR transparency the top of the atmosphere would still be a radiation surface.
If you've ever seen glass blowing you may have noticed that the glass can warm and cool such that the thermal radiation enters and leaves the visible spectrum.
At just the right point you can simultaneously see through the glass and see that the glass volume is glowing red. That would be the circumstance of an IR transparent atmosphere.
The atmosphere would still emit thermal radiation towards the planet in IR and towards space in IR. It still has an insulating effect because of this as it still moves the effective radiant surface of the planet high in the atmosphere.
Another way to look at it is this: Some of the energy at the surface will be absorbed into the atmosphere by conduction. When that happens it won't be available to be emitted into space by the surface. The warm atmosphere can hold onto that energy for a while, climb through convection, and then emit half of the energy back at the planet and half into space.
Insulation is anything that slows the movement of energy away from a system and that is precisely what I just described without involving the atmosphere absorbing any IR.
No one is discarding the atmosphere. It is kind of the MAIN PART OF THE GAME.
Doing a blackbody calculation on the surface and saying that is what it would be without an IR opaque atmosphere is discarding it.
IR opacity would certainly increase the insulative effect but it is not the sole cause (as I just described).
An IR transparent atmosphere would cause a surface temperature between Delta -30C (assuming that's right) and actual depending on its properties, mostly area density * specific heat.
Wrong. It has been studied. While I haven't personally studied the isotope data from the deep ocean I was involved in a research cruise in the north Atlantic about 30 years ago in which we were measuring a tracer gas dissolved in the ocean and were tracking a current that dipped down to the bottom of the n. Atlantic off the coast of Greenland to the NADW and we brought up water samples to measure for our gas of interest. You simply cannot tell me that we don't know about the carbon isotope fractionation in the deep water CO2.
You would need a full survey just as you would need a full survey of dug up carbon sources.
The closer the isotope ratios are between the average of those dug up and burned and those in the deep ocean the more precise and complete the survey would need to be.
Furthermore porous and carbon interactive geology is saturated below the waterline through the world and especially in the deep ocean the error bars on such things would be very large.
https://en.wikipedia.org/wiki/Marine_sediment
Calcium bicarbonate is no doubt in some sort of equilibrium in this carbonate ooze and this reaction can release the carbon dioxide without an enormous input of energy:
en.wikipedia.org
In other words the world's ocean floors are covered in an unknown depth of what is basically a carbon dioxide sponge that could due to small changes in temperature and pH release or absorb carbon dioxide that had been trapped for 100 years or 100 million years.
Depending on the age and mixture with others it could be easily distinguished (by isotope) from a particular oil field or it could be nearly identical. There is no guarantee of homogeneous mixing on either side of the equation.
It is a feedback, not a forcing.
That is gobbledegook.
I described multiple phenomenon that could only be described by differential equations. It's all simultaneously "feedback" and "forcing" if you insisted on using those words (which I would not recommend).
It doesn't stick around in the atmosphere as long as CO2. Which means it's ability to significantly and long-term affect the overall temperature is limited.
Nonsense.
Photons don't care how long the molecule they hit has been floating around. This claim is completely divorced from any relevant measurement.
Concentration distribution time and space <- matters
Radiation profile <- matters
If "sticking around" is supposed to refer to concentration distribution then water vapor sticks around a hell of a lot more than carbon dioxide does. If it refers to average time for a molecule to traverse the cycle that doesn't matter at all.
The good folks at MIT can explain it.
No excuses remember? If you understand it then you explain it. That way I don't do a ton of work analyzing a prewritten article and then you go "who knows I didn't write it".
Wrong. Climate sensitivity studies (which also include DIRECT MEASUREMENT METHODS) show that CO2 is a very important greenhouse gas.
Here's a graph of relative climate sensitivities of greenhouse gases etc.:
This is an ensemble study which also explains HOW the estimates are made. You can find it here:
https://www.nature.com/articles/ngeo337
I have no idea how "climate sensitivity" is defined, but correlation is certainly not causation when there exist known relationships which allow warmer temperatures to cause increases in atmospheric carbon dioxide.
That's setting aside all the questionable leaps that I have often observed in reconstructing deep time records of such things.
ADreamOfLiberty said:
Convection to the upper atmosphere where the IR is emitted to space was, is, and will be the dominant power transfer route.
And, the reason the entire global warming is happening is because the greenhouse effect basically just pushes the point at which the IR photons re-escape back out into space to higher and higher elevations
Yes, it would move the radiant surface up, proportional to the increase in concentration. Since carbon dioxide is a trace gas blocking only a portion of the relevant wavelengths doubling the concentration produces a minuscule shift. Add to that the fact that carbon dioxide is heavier than other gasses, even water, carbon dioxide concentrations would be at their very lowest in the upper atmosphere relative to other gasses.
Perhaps measured in centimeters.
where transfer is less efficient because of less gas molecules per square foot.
This IS the greenhouse effect in a nutshell.
That does not follow. A reduced density doesn't mean "less efficient", if the density is low it merely exposes free paths for lower layers of the atmosphere.
The reason the effective radiative surface would move up is because of the chance that an IR photon pointed towards space would strike a greenhouse gas molecule and the power would be redirected downward.