Global Mean Temperature

[Lagboltz]

Before we leave the topic of my original "3 statements" in post 56, I really need to make it clearer. The universe is full of stuff with varying amounts of internal energy. The first two following statements are simple atomic physics.

1. (Atomic physics) Each piece of stuff radiates EM energy at all wavelengths everywhere. For some particular object, the maximum possible amount of radiation at each wavelength it can emit is given by it's temperature and Plank's radiation law (Black Body (BB) radiation curve.) It almost never radiates the maximum. (emissivity is not 100%). It always emits radiation by the same BB curve no matter what stuff surrounds it.

2. (Atomic physics) Each piece of stuff absorbs any radiation that hits it, with an efficiency given by the same BB curve modified by that same emissivity. It doesn't matter how high or low the temperature of the surrounding stuff is, it still absorbs what hits it according to it's BB curve.

All the stuff creates a field of radiant energy, or lots of photons with various wavelenghs. Each piece of stuff continuously absorbs and emits radiation.

What else can we say about this space of stuff and radiation? This is where the laws of thermodynamics comes in.

3a. (First law) The total energy of the stuff is conserved (can't change.) No problem. Everyone knows that.

3b. (Second law) A hotter piece of stuff always radiates more energy to a colder piece, than the colder piece radiates to the hotter piece. Or conversely, a colder piece of stuff absorbs more energy from a hotter piece than it emits. (No mystery there. The BB curves shows that at a glance.) Thereby, colder stuff warms up and hotter stuff cools down.

(Aside remark) The above points are only about the transfer of radiant energy. Of course there are other ways heat energy can be created or transferred: Convection, conduction, heat of fusion, heat of vaporization, chemical energy (fire), nuclear energy (sun), kinetic energy (hurricane) etc... Study of the atmosphere includes many of them to various degrees, and the importance of each is different with different models of atmospheric science. Hence the controversy.

 

[Lagboltz]

I will attempt to explain backscattering, but first let's choose the best climate model by the following arguments:

300 scientists in the IPCC say .... so what, 1000 scientists say they are idiots .... we are just coming out of an ice age ... sez who? ... most of the heat is lost through convection ... well duh ... invalid! you are violating the 2nd law ... am not ... are too ... am not ... the ideal gas law explains the earth and all the planets too ... buncha crap ... you are just a pinko tree-hugging socialist ... well you are being duped by big oil companies.

Now that we have chosen the climate model, we no doubt agree on this:

The sun warms the earth by a wide band of wavelengths, from IR to UV, not including some IR greenhouse bands that have been blocked at the top of the atmosphere. The earth is too cold to radiate anything but a broad band of long wavelength IR with a wide range of spectra that depend on the local landscape or seascape. A large part of that earth IR escapes through the atmosphere out to space, to the extent that on average, the energy in is roughly equal to the energy out.

Lets look at the atomic physics effects of CO2 on that model.

The wide band of IR that the earth tries to radiate to space includes the wavelengths that the CO2 blocked. This is because the warm earth no longer "remembers" how it got warm, so the amount radiated is solely dependent on the temperature and emissivity of the local landscape. The earth radiation will include CO2 bands, and those bands will be captured by the CO2 in the atmosphere and backscatter back to earth. In short, any earth radiation in the CO2 bands will be sent back to earth. Because of that, the earth can't send that particular band of heat radiation to space, and so the earth won't be as cold as it would otherwise, and the atmosphere won't be as hot.

This explanation only used atomic physics, moreover the outcome did not violate thermodynamics and shows how the earth can get warmer with CO2. There is much more to the story. This is only meant to explain backscattering in terms of the atomic physics and not thermodynamics.

 

[dogtowner]

I will attempt to explain backscattering, but first let's choose the best climate model by the following arguments:

300 scientists in the IPCC say .... so what, 1000 scientists say they are idiots .... we are just coming out of an ice age ... sez who? ... most of the heat is lost through convection ... well duh ... invalid! you are violating the 2nd law ... am not ... are too ... am not ... the ideal gas law explains the earth and all the planets too ... buncha crap ... you are just a pinko tree-hugging socialist ... well you are being duped by big oil companies.

Now that we have chosen the climate model, we no doubt agree on this:

The sun warms the earth by a wide band of wavelengths, from IR to UV, not including some IR greenhouse bands that have been blocked at the top of the atmosphere. The earth is too cold to radiate anything but a broad band of long wavelength IR with a wide range of spectra that depend on the local landscape or seascape. A large part of that earth IR escapes through the atmosphere out to space, to the extent that on average, the energy in is roughly equal to the energy out.

Lets look at the atomic physics effects of CO2 on that model.

The wide band of IR that the earth tries to radiate to space includes the wavelengths that the CO2 blocked. This is because the warm earth no longer "remembers" how it got warm, so the amount radiated is solely dependent on the temperature and emissivity of the local landscape. The earth radiation will include CO2 bands, and those bands will be captured by the CO2 in the atmosphere and backscatter back to earth. In short, any earth radiation in the CO2 bands will be sent back to earth. Because of that, the earth can't send that particular band of heat radiation to space, and so the earth won't be as cold as it would otherwise, and the atmosphere won't be as hot.

This explanation only used atomic physics, moreover the outcome did not violate thermodynamics and shows how the earth can get warmer with CO2. There is much more to the story. This is only meant to explain backscattering in terms of the atomic physics and not thermodynamics.

replace CO2 with H2O and you may have3 something because the water can absorb the energy and then be warmer than where it sends it .

 

[Lagboltz]

replace CO2 with H2O and you may have3 something because the water can absorb the energy and then be warmer than where it sends it .

Sure, that works for me. But water doesn't seem to be as controversial as CO2, so I wanted to cover CO2 specifically doing it's little share of acting as a blanket on the earth.
I think you could be right in principle in that the CO2 wouldn't get warmer; it just backscatters its IR band of photons.

 

[palerider]

Do you really think that would have any value when he doesn't understand radiation physics?

I understand fine, and it is clear that you are doing this wandering in the wilderness bit because your explanation as to how backradiation might work failed.

By the way, I haven't been ignoring you for the past few days, I have been a bit under the weather. My daughter brought the grandkids over with runny noses and I guess I got the bug. It is amazing the volume of mucus a set of sinuses can put out if properly motivated.

 

[palerider]

I actually was on the topic that you suggested in Post 56 where I say,

1. Radiant energy flows from a cold body to a hot body.
2. Simultaneously radiant energy flows from the hot body to the cold body.
3. The net energy flow is always from the hot body to the cold body. (2nd law)

Again, your statement number one is false. Once more, the second law of thermodynamics states:

[/quote]It is not possible for heat to flow from a colder body to a warmer body without any work having been done to accomplish this flow. Energy will not flow spontaneously from a low temperature object to a higher temperature object. [/quote]

The statement is clear. The first sentence is a statement regarding heat. The second statement is one regarding energy and it is a statement made in absolute terms. ENERGY WILL NOT FLOW SPONTANEOUSLY FROM A LOW TEMPERATURE OBJECT TO A HIGHER TEMPERATURE OBJECT. There is no qualifier there stating that some sorts of energy won't flow from cold to hot, or that some energy might flow from cold to hot, or that the net flow is from hot to cold. It is a definitive statement and it says that energy will not spontaneously flow from cold to hot and therefore your statement is false. In order for it to be true, one must accept that the statement of the second law of thermodynamics is false.

 

[palerider]

I did explain things in great detail as it would in a textbook. It's only the hotplates that have relevance here. If Pale thinks there is no radiation and no photons between two hotplates at the same temperature, then he is rejecting fundamental laws of radiation physics. It's like trying to explain the orbits of planets to someone who doesn't believe in gravity.

No you didn't. You have gone off on two separate tangents thus far but have not touched the issue at hand; that being how do you claim that energy moves from the cooler atmosphere to the warmer earth where it is absorbed thus causing the earth to radiate more thus causing warming. The surface of the earth and the atmosphere are not at the same temperature and as such, your hot plate example is meaningless.

 

[palerider]

Right now the issue is not believing the laws of radiative thermodynamics. I have 6 references in posts 81 and 83 that says that bodies at the same temperature radiate to each other.

And not a single shred of repeatable, observable evidence which shows that energy can move from a cooler object to a warmer object which is the mechanism by which you and climate science state that the greenhouse effect works.

 

[palerider]

... and the hotter earth radiates even more energy back to the cooler atmosphere.

You forgot that second part of the process.
When you consider the second part, there is no net heat flow to the hotter earth, and no violation of the 2nd law.

The second law is not a statement on net flows, it is stated in absolute terms. NO ENERGY WILL FLOW FROM COLD TO HOT WITHOUT SOME WORK HAVING BEEN DONE TO ACCOMPLISH THE TASK.

Construing the second law to be about net energy flows is a fiction fabricated by people to whom the second law is an inconvenience.

 

[palerider]

Not exactly. The net effect is that the CO2 backradiation prevents the earth from loosing as much heat as it would otherwise. The earth doesn't radiate all of it's heat back to space, it is recaptured by the greenhouse gasses and backscattered again. The net result is that the earth doesn't cool off as much as it would if there were no greenhouse gasses.

There is no backradiation because energy won't move from the cooler atmosphere to the warmer surface of the earth. IR is absorbed, emitted, and then it is off to cooler climes because energy won't flow from cool to warm. I have heard some warmers try to explain trapping by claiming that the radiation goes from CO2 moleucle to CO2 molecule thus retaining it in the atmosphere longer and causing warming. That doesn't fly any more than backradiation because the IR is emitted from the CO2 molecule at a very slightly longer wavelength than at which it was absorbed which renders it invisible to other CO2 molecules.

 

[palerider]

If CO2 doesn't retain any heat, it is in close thermal contact with O2 and N2 which can retain heat. CO2 scatters it's resonant wavelengths everywhere, and that everywhere also includes earth.

Energy won't flow from cool to warm so the scattering towards the warmer earth you claim is fictitious. Energy moves in the direction of warm to cool and can't "decide" to backscatter towards a warmer object any more than a golf ball can decide to go off in some other direction than that in which it was struck.

It is said that CO2 has a cooling effect on the earth by backscattering IR into space. You can also look at backscattering as having a warming effect on outer space.

It is not backscattering, or back anything if the energy is moving from warm to cool.

Using the same physical mechanism, backscatter of CO2 in the troposphere has a warming effect on the earth mantle.

How, if energy won't move from cool to warm?

 

[palerider]

backscattering has a "warming" effect to whatever it is backscattering to.

There is no backscattering. Energy spontaneously moves from warm to cool. It will not move from cool to warm so the backscattering effect you descirbe is fictitious. It is like trying to claim that when you spray water out of a hose that some of it will go back into the hose thus giving you more water pressure.

Look, I'm not saying that CO2 warms the earth, I'm just saying that the earth doesn't get as cold as it would without it.

CO2 only alters the temperature of the earth to the extent that CO2 in the atmosphere has an effect on the atmospheric pressure. See the ideal gas laws regarding pressure and temperature.

If there were no water or other greenhouse gasses, the earth would be much colder than it is. Look at the dry Sahara, it has a day-night temperature range of 63 deg F, while a humid tropical rain forest has a day-night span of 4 to 10 deg F.

The difference between the sahara and the rain forest is due to H2O, not CO2 or any other so called greenhouse gas.

I'm not sure I understand what you mean "no backscattering from anything but the water", and that CO2 makes no difference. Both CO2 and H2O have resonant absorption/reemission bands which I would think have the same IR backscattering effect on earth, but of course H2O is much more complicated in that it is a stronger effect and can liquify, etc.

There is no backscattering just as there is no backconduction or back convection. Energy spontaneously moves from warm to cool. Backscatttering is a fiction. The IR may not emit from a CO2 molecule in precisely the opposite direction as it was moving when it was absorbed, but it emits in a direction towards cool. Again, it can no more emit in a direction towards a warmer object than water can bounce off your car and go back into your hose giving you more water pressure, or than a golf ball can go off in some other direction that that which it was struck. Energy moves from warm to cool because it has to. It doesn't attempt to turn around and go back upstream.

Sure, that works for me. But water doesn't seem to be as controversial as CO2, so I wanted to cover CO2 specifically doing it's little share of acting as a blanket on the earth. I think you could be right in principle in that the CO2 wouldn't get warmer; it just backscatters its IR band of photons.

Again, there is no backscattering. There is scattering, but backscattering is a fiction. Energy moves spontaneously from warm to cool. When the energy is emitted from the CO2 molecule, it doesn't have the option to move back towards the warmer object from which it was originally radiated. It moves from warm to cool because it has no other option. It spontaneously radiates towards a cooler temperature. There is no movenemt of energy from cool to warm so there is no possiblity of backscattering radiation any more than there is the possibility of back convection or back conduction. Backscattering is a made up bit of unphysical malarky and there is not a single observable repeatable experiment to prove that it can happen without having done some work to make it happen.

 

[Lagboltz]

Pale, look at my post 106 again. You object to item 1. I am not talking about heat radiation I am talking about photon wavelength statistics and trajectories. Do you now disagree with atomic physics? A single photon is not heat energy. If you disagree, tell me what is the temperature of a photon with a wavelength of 21 microns?

Post 106

1. (Atomic physics) Each piece of stuff radiates EM energy at all wavelengths everywhere. ....

2. (Atomic physics) Each piece of stuff absorbs any radiation that hits it....

3b. (Second law) A hotter piece of stuff always radiates more energy to a colder piece, than the colder piece radiates to the hotter piece. .... Thereby, colder stuff warms up and hotter stuff cools down.

The atomic physics phenomena 1 and 2 are used to prove the second law. They are not part of the second law. Max Planck discovered a centry ago that the atomic physics of 1 and 2 proves that net energy does not flow to a hotter object.

If you say a photon shuns aiming at a hotter object, what atomic mechanism causes that? You are continually and totally confusing the atomic properties of black bodies with the second law.

Do you still believe that photon radiation between two identical light bulbs cancel and give a black streak between them. You constantly avoid this counterexample.

 

[dogtowner]

Sure, that works for me. But water doesn't seem to be as controversial as CO2, so I wanted to cover CO2 specifically doing it's little share of acting as a blanket on the earth.
I think you could be right in principle in that the CO2 wouldn't get warmer; it just backscatters its IR band of photons.

dont think it can back scattet if.it has no ability to retain.
cant villify cars over water. i do not think they have their intentions in the right.place and they have admitted as much

 

[Lagboltz]

dont think it can back scattet if.it has no ability to retain.
cant villify cars over water. i do not think they have their intentions in the right.place and they have admitted as much

Scattering from CO2 is where a photon hits it with an energy in one of the CO2 resonance bands and knocks it to an internal excited state of vibration. After a bit, the excited state drops back to "normal" and emits the photon at that same wavelength. If that didn't happen CO2 industrial IR lasers would not work.

In the time between absorption and reemission, the CO2 molecule has rotated to a different random position and emits the photon in a random direction. If the direction is away from earth, it will continue on and hit another photon within an average distance of around 6 meters. If the photon heads for earth and is not absorbed by another CO2 molecule, it will hit earth and be absorbed. That process is all quantum mechanics. Thermodynamics does not enter at that point. That is what backscattering is. You are right that it doesn't retain that energy, it just redirects it.