## Is it possible to have a rational debate on global warming?

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chenille
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:Without an atmosphere to transport energy around the planet the night side would be very cold, and gases don't radiate as effectively as they convect.

You seem to be missing my point, though,that convection doesn't change the ultimate energy balance at all. Instead of what I've been saying, let me try to put it in the same terms as you. Once a everything is in equilibrium, we should have Pin = Pout, representing the total rate at which energy enters and leaves the planet-atmosphere system. The only way for energy to get in from space, or back out to it, is radiation.

Let's take Rt to represent all the power given off as radiation from anywhere on the planet or its atmosphere. So if all of it escapes directly into space, we should have Rt = Pout = Pin. But if we add greenhouse gases, some portion of the radiation being given off by the planet is not going to escape, and so now Pout / Rt < 1. Then we get Rt > Pin.

If we assume albedo isn't changed we would still have the same value for Pin, agreed? So adding greenhouse gases has meant that Rt has had to increase; the planet-atmosphere system is giving off more radiation than it did in the case without them. If we expect the radiation emitted is mainly thermal, that means the temperature in at least some part of the system must have gone up.

Note: of course this is an ideal case since any gas absorbing radiation is likely to change the albedo a bit. But this is where the different spectra come in: carbon dioxide doesn't interact with light from the star nearly so much as it does with infrared from the planet, so will change Pout / Rt much more than Pin, and you'll still get the same kind of result.

This is the idea of global warming in its most basic form. With all the extra things that have been brought up, I've found it somewhat hard to tell if you have any objections with this concept itself, or simply the details of how climate scientists calculate the values, or something else.

Zamfir
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### Re: Is it possible to have a rational debate on global warmi

Max, I am still completely lost on what you try to say. You just mention lots of loose facts. What is your claim? Your claim seems to be that Venus would be almost just as hot if CO2 did not absorb long-wavelength radiation. But that's obviously wrong, since in that case the atmosphere could be only slightly warmer than the clouds, and still have a net flow of IR radiation to the clouds that balances the incoming short wavelength light.

Then you started about convection. You seem to be aware that convection requires a significant temperature gradient, and therefore a much hotter surface than top. So what is your current doubt, exactly?

Max™
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### Re: Is it possible to have a rational debate on global warmi

Whoa, didn't notice I had this open still, I'll respond appropriately when I wake up, but I want to ask a question.

We know about gases which are transparent to IR, and gases which absorb IR... but we're overlooking something, aren't we?

Can a gas which doesn't absorb IR still emit IR?

Taking that one step further, can a gas which doesn't absorb IR be heated by any other method?
mu

sigsfried
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### Re: Is it possible to have a rational debate on global warmi

Can a gas which doesn't absorb IR still emit IR?

No (Microscopic reversibility states that "Corresponding to every individual process there is a reverse process, and in a state of equilibrium the average rate of every process is equal to the average rate of its reverse process"), that said a gas is never going to not absorb any IR, but generally if it can barely absorb it it will barely emit it, but it can be heated by other processes.

morriswalters
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### Re: Is it possible to have a rational debate on global warmi

BattleMoose wrote:
Max™ wrote:
Then, I want you to calculate how much is going out, using only, how much energy is coming in.

>.> From that energy budget image we get the figures of 342 W/m^2 down.

Adjust 342 W/m^2 for albedo and it should be right around 239 W/m^2, right?

So I would assume the top of the atmosphere radiates 239 W/m^2.

No way I'm going to try to work out the total number of Watts entering the climate system, but I'm pretty sure it will work out to about the same number leaving.

Again, I was asking you to calculate how much was leaving, not entering. Which is something that you should be able to do, if your assertion was correct. Which its not. Its very wrong. The amount of energy that the earth emits is dependent on a whole range of parameters, most importantly being the actual temperature of the surface.

Suffice to say, a lot of what you have been saying about radiation has just been so wrong. And its impossible to correct you because you just argue.

No way I'm going to try to work out the total number of Watts entering the climate system, but I'm pretty sure it will work out to about the same number leaving.

I don't have anything to add but I'm having a hard time this last bit. I'm not sure how to parse it. Are you saying that the energy leaving earth is different then the energy coming in?

BattleMoose
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### Re: Is it possible to have a rational debate on global warmi

morriswalters wrote:I don't have anything to add but I'm having a hard time this last bit. I'm not sure how to parse it. Are you saying that the energy leaving earth is different then the energy coming in?

That's pretty much what makes it global warming. The Earth is absorbing more energy than its emitting and thus heating up.

Max™
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### Re: Is it possible to have a rational debate on global warmi

sigsfried wrote:
Can a gas which doesn't absorb IR still emit IR?

No (Microscopic reversibility states that "Corresponding to every individual process there is a reverse process, and in a state of equilibrium the average rate of every process is equal to the average rate of its reverse process"), that said a gas is never going to not absorb any IR, but generally if it can barely absorb it it will barely emit it, but it can be heated by other processes.

Right!

BattleMoose wrote:
No way I'm going to try to work out the total number of Watts entering the climate system, but I'm pretty sure it will work out to about the same number leaving.

Hmmm.

Pretty sure that says 235 (342-107, for 168+67 absorbed) W/m^2 makes it into the climate system, and 235 W/m^2 makes it out.
mu

chenille
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### Re: Is it possible to have a rational debate on global warmi

sigsfried wrote:
Can a gas which doesn't absorb IR still emit IR?

No (Microscopic reversibility states that "Corresponding to every individual process there is a reverse process, and in a state of equilibrium the average rate of every process is equal to the average rate of its reverse process"), that said a gas is never going to not absorb any IR, but generally if it can barely absorb it it will barely emit it, but it can be heated by other processes.

This is wrong, sigsfried. You are thinking of an individual gas molecule, but once you have a denser gas where they are colliding all the time, you will get blackbody radiation. Microscopic reversibility doesn't apply so well to systems with that many particles, as per the second law of thermodynamics. So yes, the gas can and will still emit infrared as part of a blackbody spectrum. Max™ said he understood this, but he is mistaken here.

Max™ wrote:Pretty sure that says 235 W/m^2 makes it into the climate system, and 235 W/m^2 makes it out.

Ultimately you and battlemoose are talking about different things. You are only considering systems in a state of equilibrium with space. He's talking about transitions: once you do something like change the amount of greenhouse gases, paint the surface black, or so on, Pin and Pout will be different until things warm (or cool) to a new equilibrium. This is how I was describing things at first too, and it has led to a lot of talking past one another. I am happy to stick to the equilibrium cases, but know they won't necessarily apply to a climate in transition.

Something I am not sure if you agree with or not is that Pin = Pout does not determine the amount of energy present in the planet-atmosphere system at any given time. Imagine a channel with 235 L/s of water pouring in, and 235 L/s of water draining out. How much water is in the channel? Obviously there is no single answer; if the water runs straight to the drain, there will be relatively little, but if it spends a long time swirling around the channel first, there can be much more. The same thing applies to energy flow through a system, so if it is recirculated, you can have more energy and so temperature present for the same power input.
Last edited by chenille on Mon Sep 24, 2012 3:43 pm UTC, edited 2 times in total.

sigsfried
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### Re: Is it possible to have a rational debate on global warmi

This is wrong, sigsfried. You are thinking of an individual gas molecule, but once you have a denser gas where they are colliding all the time, you will get blackbody radiation. Microscopic reversibility doesn't apply so well to systems with that many particles, as per the second law of thermodynamics. So yes, the gas can and will still emit infrared as part of a blackbody spectrum. Max™ said he understood this, but he is mistaken here

But surely we see a marked suppression in the emission at any point that we see a marked drop in the absorption, otherwise it wouldn't obey detailed balance (which is true of macroscopic objects).

chenille
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### Re: Is it possible to have a rational debate on global warmi

Ok, I have explained that wrong. Yes, any gas warm enough to be emitting infrared through collisions will also have to absorb it to some extent. But it is not necessarily going to be very important; a two molecule collision that releases a photon is going to be much more likely than its reverse, where a photon encounters two molecules that happen to be ready to absorb it. When people talk about carbon dioxide as being opaque to infrared, they mean in excess of this. The absorption comes about through transitions of energy within a single molecule, but usually those are less important for emission, since it will likely collide first.

So you can still have a case where the gas absorbs mainly in one region of the spectrum, and emits mainly in another. The barely-absorbs-barely-emits rule doesn't apply. I'm not sure where Max™ is going with this, though, since it doesn't change the basic principle here.

Charlie!
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:Pretty sure that says 235 (342-107, for 168+67 absorbed) W/m^2 makes it into the climate system, and 235 W/m^2 makes it out.

Correct (well, the number seem a little off, but whatever) - the difference from the greenhouse effect is mostly to decrease the "outgoing longwave radiation" part by ~1.6 W/m^2.

Which isn't much relative to the total energy budget. But if you apply 1.6 watts per square meter over the course of a century, you can get increases on the order of degrees.
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Max™
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### Re: Is it possible to have a rational debate on global warmi

chenille wrote:Ok, I have explained that wrong. Yes, any gas warm enough to be emitting infrared through collisions will also have to absorb it to some extent. But it is not necessarily going to be very important; a two molecule collision that releases a photon is going to be much more likely than its reverse, where a photon encounters two molecules that happen to be ready to absorb it. When people talk about carbon dioxide as being opaque to infrared, they mean in excess of this. The absorption comes about through transitions of energy within a single molecule, but usually those are less important for emission, since it will likely collide first.

So you can still have a case where the gas absorbs mainly in one region of the spectrum, and emits mainly in another. The barely-absorbs-barely-emits rule doesn't apply. I'm not sure where Max™ is going with this, though, since it doesn't change the basic principle here.

Well, you may have noticed I am bothered by the way CO2 is presented as preferentially emitting infrared over convection... a very subtle point is that I'm not doubting that there is a lot of infrared bouncing around in the atmosphere. While O2 and N2 don't emit across a broad spectrum, and don't absorb across a broad spectrum, the idea that all or even most of the downward-emitted infrared radiation is from CO2--or can be treated as being from CO2 alone--is rather absurd when you think about it, isn't it? You wanna talk about kicking thermodynamics while it's down, wouldn't the bulk of the atmosphere being unable to radiate sorta be magic?

Btw, I think the highest reliable measurement of any energy imbalance is closer to one third of the 1.6 W/m^2 figure mentioned above, a quick check shows that CERES found 0.58 W/m^2 less than the value expected according to the average albedo figure.
mu

oxoiron
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### Re: Is it possible to have a rational debate on global warmi

MaxTM, I'm going to run through this step-by-step, so you can see how CO2 helps keep heat from leaving the planet. If you have any questions or arguments after reading this, I would be happy to address them.

1) Some of the visible light produced by the sun strikes the ground and is absorbed.

2) Some of the visible light absorbed by the ground is converted to heat energy.

3) Some of that heat energy is released as IR radiation.

4) Some of that IR radiation is absorbed by CO2.

5) Some of that IR radiation is re-emitted in random directions. Roughly 50% is emitted toward space and the other 50% is emitted toward earth.

6) Let us assume for purposes of this discussion that two photons were emitted, one leaving earth and the other hitting it.

7) The photon leaving earth exits with a portion of the energy the sun delivered to the ground. So far, so good; we are returning heat to whence it came.

8) The photon re-emitted toward earth is absorbed and reconverted to heat energy. Uh-oh! Now the earth's temperature just increased a little.

I've deliberately kept this very simple. If you disagree with any of the above statements, please address them individually. If you want to bring up side arguments resulting from my over-simplification, I would also be happy to discuss them (there are a few, but I deliberately sidestepped them to keep this elementary).

I'll also address your convection issue. If this has already been completed to your satisfaction, ignore the following: Convection merely moves heat from one spot in a gas to another. Heat cannot leave the earth through convection, because there is an insignificant amount of gas in interplanetary space. I know other have pointed this out, but I have not seen you acknowledge it. If I missed it and I'm beating a dead horse, I apologize.
"Whenever you find yourself on the side of the majority, it is time to reform (or pause and reflect)."-- Mark Twain
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Max™
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### Re: Is it possible to have a rational debate on global warmi

oxoiron wrote:MaxTM, I'm going to run through this step-by-step, so you can see how CO2 helps keep heat from leaving the planet. If you have any questions or arguments after reading this, I would be happy to address them.

1) Some of the visible light produced by the sun strikes the ground and is absorbed. *check*

2) Some of the visible light absorbed by the ground is converted to heat energy. *check*

3) Some of that heat energy is released as IR radiation. *check*

4) Some of that IR radiation is absorbed by CO2. *check*

5) Some of that IR radiation is re-emitted in random directions. Roughly 50% is emitted toward space and the other 50% is emitted toward earth. *check*

6) Let us assume for purposes of this discussion that two photons were emitted, one leaving earth and the other hitting it. *check*

7) The photon leaving earth exits with a portion of the energy the sun delivered to the ground. So far, so good; we are returning heat to whence it came. *check*

8) The photon re-emitted toward earth is absorbed and reconverted to heat energy. Uh-oh! Now the earth's temperature just increased a little. *check*

I've deliberately kept this very simple. If you disagree with any of the above statements, please address them individually. If you want to bring up side arguments resulting from my over-simplification, I would also be happy to discuss them (there are a few, but I deliberately sidestepped them to keep this elementary).

I'll also address your convection issue. If this has already been completed to your satisfaction, ignore the following: Convection merely moves heat from one spot in a gas to another. Heat cannot leave the earth through convection, because there is an insignificant amount of gas in interplanetary space. I know other have pointed this out, but I have not seen you acknowledge it. If I missed it and I'm beating a dead horse, I apologize.

No need to apologize at all about convection, you are quite right. I do know convection can't transfer heat to space (just up to the tropopause). Still, discussing radiation downwards isn't discussing heat transfer to space either, it's discussing heat transfer pretty much exclusively in the troposphere.

Note to point 8, can we only get this effect from CO2? As discussed above, I don't think we can.

Further, in a convecting atmosphere with realistic infrared emission (rather than one composed by almost 99% from some sort of magic ideal non-absorbing/emitting gas) it should occur that infrared energy which originated from the surface almost directly under the sun can wind up being distributed to cooler parts of the surface.

Energy picked up by the atmosphere over Costa Rica which wound up being re-emitted over Canada and warming it, that's fine.

Energy from Costa Rica being absorbed by only CO2 over Costa Rica and then being re-emitted over Costa Rica and warming it bothers me for some reason.
mu

chenille
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:Well, you may have noticed I am bothered by the way CO2 is presented as preferentially emitting infrared over convection... a very subtle point is that I'm not doubting that there is a lot of infrared bouncing around in the atmosphere. While O2 and N2 don't emit across a broad spectrum, and don't absorb across a broad spectrum, the idea that all or even most of the downward-emitted infrared radiation is from CO2--or can be treated as being from CO2 alone--is rather absurd when you think about it, isn't it? You wanna talk about kicking thermodynamics while it's down, wouldn't the bulk of the atmosphere being unable to radiate sorta be magic?

Before I worry about that, is this actually where you think carbon dioxide works differently than the current models? Because they don't affect the basic idea of why it would raise temperatures, the stuff I said about Rt and the total energy in the system, but you haven't said anything more about that. It doesn't make sense to keep focusing on specifics without knowing whether you agree with the general principle.

Max™
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### Re: Is it possible to have a rational debate on global warmi

chenille wrote:
Max™ wrote:Well, you may have noticed I am bothered by the way CO2 is presented as preferentially emitting infrared over convection... a very subtle point is that I'm not doubting that there is a lot of infrared bouncing around in the atmosphere. While O2 and N2 don't emit across a broad spectrum, and don't absorb across a broad spectrum, the idea that all or even most of the downward-emitted infrared radiation is from CO2--or can be treated as being from CO2 alone--is rather absurd when you think about it, isn't it? You wanna talk about kicking thermodynamics while it's down, wouldn't the bulk of the atmosphere being unable to radiate sorta be magic?

Before I worry about that, is this actually where you think carbon dioxide works differently than the current models? Because they don't affect the basic idea of why it would raise temperatures, the stuff I said about Rt and the total energy in the system, but you haven't said anything more about that. It doesn't make sense to keep focusing on specifics without knowing whether you agree with the general principle.

As I've been trying to explain, hence the seemingly random things I "bring up", there is a strange idea that only CO2 emits infrared in significant enough quantities to matter besides H2O, when the actual effect is that only CO2 and H2O absorb infrared in significant quantities, pretty sure the whole atmosphere emits infrared, and with the whole atmosphere doing so, you can actually transfer energy around the system, and as the whole atmosphere is larger than the visible disc of the sun, you can even arrange your energy flows in a manner that makes it seem like the atmosphere is "holding on" to energy.

Models which attribute significant warming effects to CO2 do this by treating several processes as dominated by radiative transfer, hence the term radiative forcing, which is obviously not how things actually work.

They state this flat out that the atmosphere does not behave this way, it is just VERY difficult to model convective processes for a coupled ocean/atmosphere/surface model.

The idea that all downward radiation from the atmosphere can be presented in terms of radiation from CO2 downwards makes it seem like CO2 molecules are tiny little suns, which again, is completely and totally wrong.

Now, most of the atmosphere does rather preferentially favor convection, given that it is a gas, and made of molecules which don't have broad IR absorption bands... so treating it in the manner I described above can lead one to mistakenly conclude that while CO2 molecules aren't little suns, they are basically mirrors... which again, is completely and totally wrong.
mu

oxoiron
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:
Spoiler:
oxoiron wrote:MaxTM, I'm going to run through this step-by-step, so you can see how CO2 helps keep heat from leaving the planet. If you have any questions or arguments after reading this, I would be happy to address them.

1) Some of the visible light produced by the sun strikes the ground and is absorbed. *check*

2) Some of the visible light absorbed by the ground is converted to heat energy. *check*

3) Some of that heat energy is released as IR radiation. *check*

4) Some of that IR radiation is absorbed by CO2. *check*

5) Some of that IR radiation is re-emitted in random directions. Roughly 50% is emitted toward space and the other 50% is emitted toward earth. *check*

6) Let us assume for purposes of this discussion that two photons were emitted, one leaving earth and the other hitting it. *check*

7) The photon leaving earth exits with a portion of the energy the sun delivered to the ground. So far, so good; we are returning heat to whence it came. *check*

8) The photon re-emitted toward earth is absorbed and reconverted to heat energy. Uh-oh! Now the earth's temperature just increased a little. *check*

I've deliberately kept this very simple. If you disagree with any of the above statements, please address them individually. If you want to bring up side arguments resulting from my over-simplification, I would also be happy to discuss them (there are a few, but I deliberately sidestepped them to keep this elementary).

I'll also address your convection issue. If this has already been completed to your satisfaction, ignore the following: Convection merely moves heat from one spot in a gas to another. Heat cannot leave the earth through convection, because there is an insignificant amount of gas in interplanetary space. I know other have pointed this out, but I have not seen you acknowledge it. If I missed it and I'm beating a dead horse, I apologize.

No need to apologize at all about convection, you are quite right. I do know convection can't transfer heat to space (just up to the tropopause). Still, discussing radiation downwards isn't discussing heat transfer to space either, it's discussing heat transfer pretty much exclusively in the troposphere.
Note to point 8, can we only get this effect from CO2? As discussed above, I don't think we can.

Further, in a convecting atmosphere with realistic infrared emission (rather than one composed by almost 99% from some sort of magic ideal non-absorbing/emitting gas) it should occur that infrared energy which originated from the surface almost directly under the sun can wind up being distributed to cooler parts of the surface.

Energy picked up by the atmosphere over Costa Rica which wound up being re-emitted over Canada and warming it, that's fine.

Energy from Costa Rica being absorbed by only CO2 over Costa Rica and then being re-emitted over Costa Rica and warming it bothers me for some reason.
Regarding point 8: Other gases will also do this, just not as efficiently as CO2 (e.g. methane). I don't know why you find re-emitting Costa Rican radiation back to Costa Rica to be bothersome, but if it makes you happier, pretend it all goes to Canada. The net effect will be the same; some IR that would normally be leaving the planet is redirected earthside, resulting in a planetary temperature increase.

As I said earlier, there are many details we are ignoring, but the central argument holds.
"Whenever you find yourself on the side of the majority, it is time to reform (or pause and reflect)."-- Mark Twain
"There is not more dedicated criminal than a group of children."--addams

Max™
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### Re: Is it possible to have a rational debate on global warmi

oxoiron wrote:
Max™ wrote:
Spoiler:
oxoiron wrote:MaxTM, I'm going to run through this step-by-step, so you can see how CO2 helps keep heat from leaving the planet. If you have any questions or arguments after reading this, I would be happy to address them.

1) Some of the visible light produced by the sun strikes the ground and is absorbed. *check*

2) Some of the visible light absorbed by the ground is converted to heat energy. *check*

3) Some of that heat energy is released as IR radiation. *check*

4) Some of that IR radiation is absorbed by CO2. *check*

5) Some of that IR radiation is re-emitted in random directions. Roughly 50% is emitted toward space and the other 50% is emitted toward earth. *check*

6) Let us assume for purposes of this discussion that two photons were emitted, one leaving earth and the other hitting it. *check*

7) The photon leaving earth exits with a portion of the energy the sun delivered to the ground. So far, so good; we are returning heat to whence it came. *check*

8) The photon re-emitted toward earth is absorbed and reconverted to heat energy. Uh-oh! Now the earth's temperature just increased a little. *check*

I've deliberately kept this very simple. If you disagree with any of the above statements, please address them individually. If you want to bring up side arguments resulting from my over-simplification, I would also be happy to discuss them (there are a few, but I deliberately sidestepped them to keep this elementary).

I'll also address your convection issue. If this has already been completed to your satisfaction, ignore the following: Convection merely moves heat from one spot in a gas to another. Heat cannot leave the earth through convection, because there is an insignificant amount of gas in interplanetary space. I know other have pointed this out, but I have not seen you acknowledge it. If I missed it and I'm beating a dead horse, I apologize.

No need to apologize at all about convection, you are quite right. I do know convection can't transfer heat to space (just up to the tropopause). Still, discussing radiation downwards isn't discussing heat transfer to space either, it's discussing heat transfer pretty much exclusively in the troposphere.
Note to point 8, can we only get this effect from CO2? As discussed above, I don't think we can.

Further, in a convecting atmosphere with realistic infrared emission (rather than one composed by almost 99% from some sort of magic ideal non-absorbing/emitting gas) it should occur that infrared energy which originated from the surface almost directly under the sun can wind up being distributed to cooler parts of the surface.

Energy picked up by the atmosphere over Costa Rica which wound up being re-emitted over Canada and warming it, that's fine.

Energy from Costa Rica being absorbed by only CO2 over Costa Rica and then being re-emitted over Costa Rica and warming it bothers me for some reason.
Regarding point 8: Other gases will also do this, just not as efficiently as CO2 (e.g. methane). I don't know why you find re-emitting Costa Rican radiation back to Costa Rica to be bothersome, but if it makes you happier, pretend it all goes to Canada. The net effect will be the same; some IR that would normally be leaving the planet is redirected earthside, resulting in a planetary temperature increase.

As I said earlier, there are many details we are ignoring, but the central argument holds.

It bothers me for Costa Rica to be at a temperature which causes it to emit radiation that warms something cooler, which then reaches a temperature that causes it to emit radiation that warms something cooler, in this case Costa Rica?

I agree with you right up to the "resulting in a planetary temperature increase" because of the implication that CO2 alone is responsible for this by trapping energy.
mu

chenille
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:As I've been trying to explain, hence the seemingly random things I "bring up", there is a strange idea that only CO2 emits infrared in significant enough quantities to matter besides H2O, when the actual effect is that only CO2 and H2O absorb infrared in significant quantities, pretty sure the whole atmosphere emits infrared, and with the whole atmosphere doing so, you can actually transfer energy around the system, and as the whole atmosphere is larger than the visible disc of the sun, you can even arrange your energy flows in a manner that makes it seem like the atmosphere is "holding on" to energy.

I understand that's where you want to get to, but I still can't tell if this means you agree with the general idea that adding greenhouse gases can increase temperature or not. As I've explained, it doesn't depend on the particulars you're discussing. If you could give a nod to the stuff I've said about Pin, Pout, Rt, and total energy, it would really help clarify your position.

Max™
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### Re: Is it possible to have a rational debate on global warmi

chenille wrote:
Max™ wrote:As I've been trying to explain, hence the seemingly random things I "bring up", there is a strange idea that only CO2 emits infrared in significant enough quantities to matter besides H2O, when the actual effect is that only CO2 and H2O absorb infrared in significant quantities, pretty sure the whole atmosphere emits infrared, and with the whole atmosphere doing so, you can actually transfer energy around the system, and as the whole atmosphere is larger than the visible disc of the sun, you can even arrange your energy flows in a manner that makes it seem like the atmosphere is "holding on" to energy.

I understand that's where you want to get to, but I still can't tell if this means you agree with the general idea that adding greenhouse gases can increase temperature or not. As I've explained, it doesn't depend on the particulars your discussing. If you could give a nod to the stuff I've said about Pin, Pout, Rt, and total energy, it would really help clarify your position.

Adding any gas will result in an equilibrium temperature change, CO2 and H2O are no different, they're only better at absorbing infrared than most of the other gases, not better at holding energy, I don't think either have a higher specific heat (that is related to the freezing point isn't it?) than O2 or N2, so ultimately it is a case of a model simplifying assumption leading to CO2 being given credit for the properties of the rest of the atmosphere, isn't it?

The energy which "doesn't escape" is at best half a watt per meter squared, and that calculation is using an unknown method of determining albedo, odd energy transfer assumptions, and appears to treat three things as roughly the same size:

1. The visible disc of the sun

2. The visible portion of the atmosphere emitting infrared which reaches the ground

3. The surface of the tropopause where the 235 W/m^2 upwards figure is calculated for
mu

chenille
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### Re: Is it possible to have a rational debate on global warmi

I'm not talking about specific heat, which has nothing to do with anything; I'm talking about the stuff I said about recirculation increasing total energy and Rt going up. Does it make sense to you, or do you disagree with some part of it? If you don't answer that, I can't meaningfully discuss the subject with you.

morriswalters
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### Re: Is it possible to have a rational debate on global warmi

Again I don't have anything new to offer, but I have another question. Why does the system not oscillate. What mechanism drives it towards equilibrium?

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### Re: Is it possible to have a rational debate on global warmi

chenille wrote:I'm not talking about specific heat, which has nothing to do with anything; I'm talking about the stuff I said about recirculation increasing total energy and Rt going up. Does it make sense to you, or do you disagree with some part of it? If you don't answer that, I can't meaningfully discuss the subject with you.

It makes sense, but I disagree with the idea that CO2 is mostly/significantly/completely/largely responsible for it.

morriswalters wrote:Again I don't have anything new to offer, but I have another question. Why does the system not oscillate. What mechanism drives it towards equilibrium?

Very good question, I'd say gravity is an important part (but when I see "equilibrium" in context with the atmosphere I think "hydrostatic equilibrium" which may not be what you meant), though it might depend on whether you're asking about the atmosphere system, or a small subset, or the entire Earth/Sun system.
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morriswalters
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### Re: Is it possible to have a rational debate on global warmi

The climate system.

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### Re: Is it possible to have a rational debate on global warmi

morriswalters wrote:The climate system.

Well, gravity is a part, but I'm not sure that the "no oscillation" condition is completely satisfied when so broadly applied.

Btw, gotta say thanks in general for everyone making me go over things more closely and really consider my arguments while identifying mistakes due to incorrect or nonstandard use of language.
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:
chenille wrote:I'm not talking about specific heat, which has nothing to do with anything; I'm talking about the stuff I said about recirculation increasing total energy and Rt going up. Does it make sense to you, or do you disagree with some part of it? If you don't answer that, I can't meaningfully discuss the subject with you.
It makes sense, but I disagree with the idea that CO2 is mostly/significantly/completely/largely responsible for it.
Why? Do you contend that other gases do a better job of reabsorbing IR radiation from the surface before it can get to space? The gases that don't absorb surface radiation are less important for the greenhouse effect because they don't absorb surface radiation, which is what the greenhouse effect is about. If the atmosphere was made entirely of gases that are transparent to IR, Earth would be much cooler, because its IR radiation would all just go directly back into space.

Therefore, it's the gases that are *not* as transparent to IR that contribute to warming.

So, again, are you arguing that climate models don't account for the actual absorption spectra of atmospheric gases?

(And no one who has any idea what they're talking about has ever claimed CO2 is "completely" responsible for it. Everyone is well aware that it's not the only greenhouse gas.)
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Max™
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### Re: Is it possible to have a rational debate on global warmi

gmalivuk wrote:
Max™ wrote:
chenille wrote:I'm not talking about specific heat, which has nothing to do with anything; I'm talking about the stuff I said about recirculation increasing total energy and Rt going up. Does it make sense to you, or do you disagree with some part of it? If you don't answer that, I can't meaningfully discuss the subject with you.
It makes sense, but I disagree with the idea that CO2 is mostly/significantly/completely/largely responsible for it.
Why? Do you contend that other gases do a better job of reabsorbing IR radiation from the surface before it can get to space? The gases that don't absorb surface radiation are less important for the greenhouse effect because they don't absorb surface radiation, which is what the greenhouse effect is about. If the atmosphere was made entirely of gases that are transparent to IR, Earth would be much cooler, because its IR radiation would all just go directly back into space.

Therefore, it's the gases that are *not* as transparent to IR that contribute to warming.

So, again, are you arguing that climate models don't account for the actual absorption spectra of atmospheric gases?

(And no one who has any idea what they're talking about has ever claimed CO2 is "completely" responsible for it. Everyone is well aware that it's not the only greenhouse gas.)

There is no such thing as a gas which is completely transparent to IR, but that is a minor point.

Every single molecule of air that contacts the ground will transport heat away, any molecule that absorbs any IR will, but even if you only had gases that were warmed from collisions with other molecules, they would still radiate IR at some point.

Btw, I'm not arguing that climate models don't account for it, I'm saying flat out that climate models are constructed in a way that all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O.

Yes, everyone is aware that CO2 is not the only greenhouse gas, but you yourself suggested that there are gases which don't absorb surface radiation, which is often associated with a belief that those same gases don't emit IR.
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### Re: Is it possible to have a rational debate on global warmi

Can you suggest why they should look at conduction or convection?

BattleMoose
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### Re: Is it possible to have a rational debate on global warmi

morriswalters wrote:Again I don't have anything new to offer, but I have another question. Why does the system not oscillate. What mechanism drives it towards equilibrium?

The short answer is that it does oscillate. Oscillation though is not the right word to be using because the variations aren't exactly similar, but certainly the system is dynamic.

Data from ice cores yields some data on how it has oscillated. http://en.wikipedia.org/wiki/File:Vostok_Petit_data.svg

Inputs into the Earth System, radiation from the sun, varies in relation to the milankovitch cycles, relating to 3 different cycles in our orbit and each influencing how much radiation the Earth receives at the top of atmosphere. The cycles from the ice cores, loosely (badly), correlate to the milankovtich cycles. The current thinking, as I understand it, is variations in radiation input due to milankovitch cycles initiate changes, positive feedback loops, in the Earth System which release carbon and increase temperature. In time, process that take carbon out of the atmosphere begin to dominate and the temperature of the planet cools.

What the Earth is like at any given time will have huge impact on its overall temperature, while incoming radiation is certainly an influence. Ice cover, atmospheric composition, vegetation cover, carbon in the oceans, there are a huge number of influences and feedback loops, both positive and negative.

For a very simplistic and idealized case to show how the biota may interact with the climate Daisyworld was suggested. http://en.wikipedia.org/wiki/Daisyworld
It shows how an oscillation in the climate system is set up just through the biota with constant inputs. http://en.wikipedia.org/wiki/File:This_ ... _White.ogv

In time, (tens of thousands to hundreds of thousands of years), the biota will sequester the carbon back into the ocean floor and the land. Primarily dying oceanic organisms, which fall to the ocean floor, may sequester the carbon that is in them, into the ocean floor. Very slowly reducing the total amount of carbon in the atmosphere.

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### Re: Is it possible to have a rational debate on global warmi

morriswalters wrote:Can you suggest why they should look at conduction or convection?

Because the bulk of the atmosphere is heated by such processes and also emits infrared, not just GHG's?
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:
morriswalters wrote:Can you suggest why they should look at conduction or convection?
Because the bulk of the atmosphere is heated by such processes and also emits infrared, not just GHG's?
Yes, infrared which is in turn reabsorbed by GHGs instead of escaping into space. I'm not sure what you think would be different in much more complex models.

More of any gas that is less transparent to IR will result in more heat staying in the Earth+atmosphere which means temperature will rise. Do you disagree with this gross oversimplification?
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chenille
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:Every single molecule of air that contacts the ground will transport heat away, any molecule that absorbs any IR will, but even if you only had gases that were warmed from collisions with other molecules, they would still radiate IR at some point.

Yes, but that doesn't matter because the warming doesn't depend on which gas or solid the infrared happens to come from. If we assume Pin = Pout, then regardless of which gases are doing the emission, the total will have to be Rt = Pin / (Pout / Rt), right? So the deciding factors are Pin, the power from the star, and Pout / Rt, the portion of radiation that is absorbed again. That's what makes it recirculate and so changes how much energy is passing through the system at a given time.

The important thing isn't whether carbon dioxide, water, and methane are shining directly back to the surface, it's that they have a large effect on the energy that would be escaping into space. Since most of that is infrared, molecules that don't absorb it very well won't reduce the proportion that escapes so much. So even if all of the heat ended up transferred to them and they were the only re-emitters, they still can have less effect on the total amount.

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### Re: Is it possible to have a rational debate on global warmi

gmalivuk wrote:
Max™ wrote:
morriswalters wrote:Can you suggest why they should look at conduction or convection?
Because the bulk of the atmosphere is heated by such processes and also emits infrared, not just GHG's?
Yes, infrared which is in turn reabsorbed by GHGs instead of escaping into space. I'm not sure what you think would be different in much more complex models.

More of any gas that is less transparent to IR will result in more heat staying in the Earth+atmosphere which means temperature will rise. Do you disagree with this gross oversimplification?

Infrared which is just as likely to make it to the ground and contribute to that portion of the energy flux as it is to be absorbed by a GHG*.

I do disagree that it will result in heat staying in the system, but I think it is because of the issue mentioned earlier about the distinction between temperature heat and energy.

ANY gas will contribute to the IR flux reaching the ground, this is in no way unique to CO2 or other GHG's, the only thing unique to those gases is the absorption of IR directly across a broad spectrum.

That causes them to gain energy and jostle nearby molecules, transferring heat through convection, and occasionally GHG molecules will emit IR downwards.

That is in no way a significant portion of the energy transfer, and the amount of IR emitted downwards from GHG's compared to the rest of the atmosphere is in no way significant.

The only way it appears significant is if you treat ALL downward IR as being due to CO2/H2O/other GHG's, which is wrong.

chenille wrote:
Max™ wrote:Every single molecule of air that contacts the ground will transport heat away, any molecule that absorbs any IR will, but even if you only had gases that were warmed from collisions with other molecules, they would still radiate IR at some point.

Yes, but that doesn't matter because the warming doesn't depend on which gas or solid the infrared happens to come from. If we assume Pin = Pout, then regardless of which gases are doing the emission, the total will have to be Rt = Pin / (Pout / Rt), right? So the deciding factors are Pin, the power from the star, and Pout / Rt, the portion of radiation that is absorbed again. That's what makes it recirculate and so changes how much energy is passing through the system at a given time.

There is as much a geometric effect going on here as a radiative one, but yes, as I said, any gas will adjust the rate at which energy passes through the system.

Honestly you could really consider ANY gas a greenhouse gas by the definition of "absorbs and emits IR which strikes the ground", but that definition overlooks that in the real atmosphere and actual greenhouses, radiative transfer is a minor component compared to convection.

As all gases will tend to convect, and until a molecule reaches an altitude where it can emit radiation or is struck by energetic enough molecules to trigger emission of a photon, all gases will carry energy around in the system at a rate slower than the energy leaving directly from the surface to space.

The important thing isn't whether carbon dioxide, water, and methane are shining directly back to the surface, it's that they have a large effect on the energy that would be escaping into space. Since most of that is infrared, molecules that don't absorb it very well won't reduce the proportion that escapes so much. So even if all of the heat ended up transferred to them and they were the only re-emitters, they still can have less effect on the total amount.

Yes, CO2 and H2O absorb infrared across a wider portion of the spectrum than O2 and N2, but O2 and N2 outnumber GHG molecules by a huge amount... how little would each non-GHG molecule have to emit in order for their contribution to be negligible?

How could those molecules have similar temperatures to CO2/H2O without emitting significant amounts of IR as well?
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chenille
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:That is in no way a significant portion of the energy transfer, and the amount of IR emitted downwards from GHG's compared to the rest of the atmosphere is in no way significant.

Max™ wrote:As all gases will tend to convect, and until a molecule reaches an altitude where it can emit radiation or is struck by energetic enough molecules to trigger emission of a photon, all gases will carry energy around in the system at a rate slower than the energy leaving directly from the surface to space.

Max™ wrote:How could those molecules have similar temperatures to CO2/H2O without emitting significant amounts of IR as well?

Maybe you are now complaining about more detailed particulars of the models, and not the basic idea that GHGs are responsible for the increased energy in the system. But otherwise, I just finished explaining why the thing that determines warming is what proportion of energy escapes into space, and so how much is re-absorbed, not at all how much of the infrared is emitted by each gas. And this reply contradicts that without even acknowledging that's what I said.

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### Re: Is it possible to have a rational debate on global warmi

Yeah, the IR coming down from the air isn't the point. The point is the IR that's *not* getting into space on account of gases in the air that absorb it first, keeping that energy in the system as heat.
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### Re: Is it possible to have a rational debate on global warmi

Btw, I'm not arguing that climate models don't account for it, I'm saying flat out that climate models are constructed in a way that all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O.

No, no they are not constructed that way. The things are even called General Circulation Models.

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### Re: Is it possible to have a rational debate on global warmi

Zamfir wrote:
Btw, I'm not arguing that climate models don't account for it, I'm saying flat out that climate models are constructed in a way that all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O.

No, no they are not constructed that way. The things are even called General Circulation Models.

Do you know what parametrization of sub-grid processes means?

Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. To “run” a model, scientists divide the planet into a 3-dimensional grid, apply the basic equations, and evaluate the results. Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and evaluate interactions with neighboring points. The winds, heat transfer and other quantities are only used to compute a final result so they do not need to correspond to real world conditions, and in some numerical schemes fictitious quantities are introduced.

* AGCMs consist of a dynamical core which integrates the equations of fluid motion, typically for:
** surface pressure
** horizontal components of velocity in layers
** temperature and water vapor in layers
* There is generally a radiation code, split into solar/short wave and terrestrial/infra-red/long wave
* Parametrizations are used to include the effects of various processes. All modern AGCMs include parameterizations for:
** convection
** land surface processes, albedo and hydrology
** cloud cover
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### Re: Is it possible to have a rational debate on global warmi

Max™ wrote:
Zamfir wrote:
Btw, I'm not arguing that climate models don't account for it, I'm saying flat out that climate models are constructed in a way that all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O.

No, no they are not constructed that way. The things are even called General Circulation Models.

Do you know what parametrization of sub-grid processes means?

I am fairly confident you don't.

Convective process have been explicitly stated that they are included. Ergo, your assertion that, all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O., is obviously wrong.

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### Re: Is it possible to have a rational debate on global warmi

I like, in that sense that actually I am abhorrent of, how this conversation is still talking about mechanics, which is perfectly pointing out the real flaws, in my opinion, with this argument, and the issues inherent in it.

What we are doing economically and physically, with regards to mining and power generation, is unsustainable. We *know* that. Regardless of the effect on the environment, or the biosphere. So; instead of actively working to create sustainability now, with the knowledge that while it may impede medium term profits, it will allow us greater breathing room in the face of a potential resource balloon, Humanity is caught up in foolish mechanical debates that we lack the modelling power to nail down, but can make observations (And money) of.

Really. Sort out shit out, secure our biodiversity. Respect the planet for the resource it is, aesthetically, and leave our kids, and their kids', kids', kids' something worthwhile.
Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy.

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### Re: Is it possible to have a rational debate on global warmi

BattleMoose wrote:
Max™ wrote:
Zamfir wrote:
Btw, I'm not arguing that climate models don't account for it, I'm saying flat out that climate models are constructed in a way that all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O.

No, no they are not constructed that way. The things are even called General Circulation Models.

Do you know what parametrization of sub-grid processes means?

I am fairly confident you don't.

Convective process have been explicitly stated that they are included. Ergo, your assertion that, all of the energy exchanged between the ground and atmosphere is treated in terms of radiative forcing by CO2 and H2O., is obviously wrong.

Parametrization of convection means it is inserted as a set value, and the actual model runs functionally treat it as an adjustment on radiative forcing.

When you say "fairly confident", you might want to make sure you're not just reacting to what you think I'm saying.
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