Weekend Open Thread – call for essays

in re john robertson…

“Long past time we tarred and feathered all involved in promoting CAGW.”

Let’s be “green” about this now. Tarring requires the use of evil fossil fuel leftovers and should not be considered as a valid approach to “natural” punishment. I would recommend the use of honey instead of tar. The honey may be boiled first in order to maintain the 2nd and 3rd degree burns consistent with the old fashioned tarring but there is a nice twist here. After the honey and feathering drop the “contestant” into the Arctic… surrounded by Polar Bears. A true CAGW believer would have no fear ’cause all the bears should have been extinct due to global warming. Punishment with the bonus of a honey treat for the bears… what could be “greener.”

“Heat doesn’t escape directly, it has to turn back in to radiation to be able to pass through the vacuum of space to escape (i think!)”
Yes; and it still does so. George mentioned the thermalization process of IR photons but at the same time there is also dethermalization ongoing, the exact opposite.
Which one of these processes dominates depends on the mean free path length of the photon, i.e. on the atmospheric density and the partial pressure of the greenhouse gases.
So above a certain height, CO2 and other triatomic gases serve as coolants, as even NASA admits, whose business it normally is to earn 1.2 billion USD in tax payer money to prove Global Warming, for instance in Gavin Schmids GISS institute.
http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/

Well I’m not sure exactly how Alex ran off the rails, there. I was questioning the common assumption, that GHG absorptions “heat”(verb) the atmosphere. Frankly, I don’t know if they do or not, but I lean towards not. >>BUT << !! it's quite clear that they do impede the escape of thermal (BB like) radiation from the solid/liquid surface, because of the resonant absorptions in the well known bands (of fine spectral lines). That physics is rather irrefutable. You do not want to die on a hill claiming that GHGs don't do anything. I don't think they do anything bad. But they certainly do something.
Analog circuit designers; IR1 , understand that if you apply a step voltage to a resistor ( R) in series with a capacitor (C) (condenser !), the output voltage on the capacitor, starts to rise (from its initial zero) at an initial rate equal to V/RC volt per second, because you have an initial current V/R amp going into the capacitor. As the voltage rises, the current drops, so the charge rate slows down. If it didn't slow down, but stayed at V/R amp, the capacitor would fully charge up to V in a time RC seconds. So we call RC the time constant of that circuit. In reality, the voltage will only get to 63% (1-1/e) in that time. It will get to 95% in three time constants, and to 99% in five time constants.
Less well known is what happens if you apply a linear ramp of voltage (dV/dt) to that same circuit. Well the input voltage starts off at zero, so now the starting charge current is also zero, but now it is the current that is increasing, at an initial linear rate, and the current will eventually build up to a limiting value of CdV/dt amp per second, and it will take five time constants (5RC) to get to 99% of that final rate.
After that the output voltage on the capacitor, will be ramping up at exactly the same rate as the input, and the charge current will be constant at the value CdV/dt. This constant current flows in the resistor R, so the voltage drop across that resistor is now constant, at the value RC dv/dt. The output voltage across the capacitor is now rising at the same rate as the input ramp, but it is delayed in time by that time constant RC. Whatever voltage the input ramp is at, the output will get to that same voltage RC seconds later.
This is exactly the same process (in analogy) that happens on the earth where the sun is inputting radiant energy at a constant rate (more or less) similar to the constant current that was flowing into our capacitor. Well it could be water running into the bathtub, couldn't it.
The delay in the escape of radiant energy to space (by GHG temporary capture), causes the Temperature, to offset at a higher static value, than it would have if the escape wasn't delayed by the GHGs. Eventually the Temperature stops rising, but at a small increment over the value it would have sans delay.
You don't have to assume, that the Atmosphere is warming at all, in this process. The excess energy is being lost at the necessary rate, to match the average solar input rate, but it takes a higher thermal radiating surface Temperature to maintain that loss rate.
I think it is a great disservice that we do to our Physics, and indeed all science students, that we teach them that Electro-magnetic radiant energy is "HEAT" (noun). It is NOT. Coal is NOT heat, nor is oil and natural gas. But we can get heating (verb) from any of those things. Temperature is a unique macro property of thermal systems, where millions of molecules are actively in mechanical collisions with each other, which could be a destruction derby process, as in gases, or it could be a shoulder shoving, while trying to rush into the ball park, with wall to wall people.
You need many molecules to have a Temperature, but a photon can be captured by just a single molecule unaided by human hand or anything else. EM radiation can be turned into "heat" with 100% efficiency, but we can't turn the heat back into radiant energy anywhere near 100%.
Some will still insist that radiation is heat; well maybe it is light, or radio, or TV or X-rays
Well it is not heat, and it is not light either. Light is all in your head. Your brain makes it up when your eye is stimulated by just a single octave of EM radiant energy from about 0.4 to 0.8 micron wavelength. That also corresponds to a range of photon energy from about 1.5 down to 0.75 electron-volt of energy.
So is a 1.5 eV photon heat, or is it light. What happens when it changes from one to the other. If 750 nm is heat, is 749 nm light or is it still heat.
Now I know that red "light" radiant energy, is about 2.0 electron-volt, that's close to the He-Ne red laser at 632.8 nm wavelength.
I also happen to know to eight significant digits, what is the wavelength of the red Cadmium line, that Michelson used to measure the meter bar. It is 6438.4696 Angstrom units. (look it up). I don't need to because in my day, everybody knew that, even some stranger down at the pub.
So if some folks, still think EM radiation is heat; is it ALL heat; or is some of it television or x-rays.
So maybe you could give me to eight significant digits, what is the starting and ending points in the EM spectrum, that defines what is heat, and what is not heat.
In my book, NONE of it is "heat" (noun), but ALL of it, can be used to "heat" (verb) something else.
Even the microwave 2.77 K background radiation can be used to "heat" (verb) a block of frozen Helium.
So can X-rays.
Not only is "light" not EM radiation, it isn't even energy.
The following formal definition of "light", is given by the commission on colorimetry, of the Optical Society of America; one of the founding organizations of the American Institute of Physics.
"Light is the (psychophysical) aspect of radiant energy of which a human observer is aware through the visual sensations which arise from the stimulation of the retina of the (human) eye. "
That's a direct quote (sans the () words) from the "Science of Color", a classic text book published by that entity.
But we Physikers get lazy, and use heat and light colloquially , although we understand what we really mean, but we confuse the lay reader by doing that.

“””””…..
nielszoo
October 5, 2014 at 2:25 pm
The problem with your explanation, as good as it is, is that it still relies on the fallacy that CO2, or any other gas at normal atmospheric pressures, actually has the time to drop all the way to ground state and radiate a photon. …..”””””
Well you are doing a lot of relying, on this or that. I am not.
I mentioned only CO2 in my first post, because somebody else specifically said that CO2 “Trapped” radiation. It was that point I was addressing. My failure to include a lengthy comment, naming each and every GHG by name, and describing its important actions, would take up all of Anthony’s bandwidth.
Your assumption that that was all I considered is just that; your assumption.
And the reason that CO2 or any other GHG does not get time to spontaneously revert to the ground state or another lower state, after its typical lifetime, is because that excited state is brutally terminated, when the molecule gets clobbered by another molecule due to the gas temperature.
If the Black Swan is in the middle of doing her 32 fouettes, en tournant , and the prince knocks her on her keister, she is not going to continue with what she was doing.
Neither do excited molecules engaging in some resonant oscillation mode. The collision prematurely terminates the performance, and the result is that the line-width of the subsequent emission (of a photon) undergoes a collision broadening, as explained by Heisenberg’s principle. dEdt > h (or hbar, depending on your units).
Phil has related on numerous occasions, that you only get spontaneous emission from CO2 or other GHGs in the rarified atmosphere of the stratosphere, where the mean time between molecular collisions is greater than the lifetime of the excited state. Those emissions have lower line widths, also because of the lower Temperature, and Doppler broadening.
Somebody else metioned CO2 “trapping” ; not me.