Global warming is not caused by CO2

[DEMcMillan]

vanesch wrote

BTW, I didn't find any reference to C-14 in the articles you cited.
The dose burden of C-14 as compared to the total natural background radiation, and even to the medical doses we are subject to, is rather small.
Concerning the coal pollution and victims, here's a link,
http://www.sierraclub.org/cleanair/factsheets/power.asp
but I agree that this is not a peer-reviewed thing at all.
There is also http://www.hsph.harvard.edu/news/pre...s10172002.html[/QUOTE]

I gave CML as a particular example of a plausible result from ¹⁴C, not as a disease conclusively shown to be based on it. I could have spent time identifying other malignancies that were found higher in Hiroshima and Nagasaki survivors and whose incidence has been falling in recent years. Those two features are enough to give plausibility to my assertion. One is enough to support the proposition that ¹⁴C should be seen as a hazard.

I was also jesting in my retreat to chemical hormesis. I am not in favor of a minimum necessary exposure to nitrogen oxides and sulfur dioxide. I think natural gas is more desirable than coal, but there is not enough. The Sierra Club boilerplate was painful because it so resembled the late Michael Crichton’s characters in State of Fear. These are the people who give us all our fuel rod “swimming pools” that I believe contribute to our rising temperatures on the Northern third of the planet (#3 Nuclear…) https://www.physicsforums.com/showthread.php?t=246980. Inventiveness is far more important than carbon taxes in getting better outcomes, hence the need for actual health burden data.

You chose to cite a Dublin experience with abolition of coal use, probably without looking into its substance. It is a good example of misrepresentation based on accidental overlapping interests. I start with the low coal use numbers for Ireland. In 1990 the total production was 30,000 short tons for a population of 3,500,000, 18 pounds per person http://www.ihndexmundi.com/energy.aspx?country=ie&product=coal&graph=production . In 1991 it fell to an almost immeasurable level, arguing that its main consumption was in the 1,000,000 person Dublin urban area at 60 pounds per person/year. It was bituminous coal, high in sulfur, but at 2 ounces/coal a day hardly threatening. It had been introduced into domestic use in heating water during the oil crisis in 1979 (Iran). http://www.airquality.co.uk/archive...Dublin_Smoky_Fuel_Ban_Detailed_Assessment.doc I could not identify the actual device but it clearly was used abundantly in some outlying Dublin areas. The SO2 level given was just over .03 ppm, the US National Standard (see below). Excess deaths in the 1952 and 1962 London episodes were associated with a 1.7 ppm SO₂ level http://www.fluoridealert.org/F-sulfur.htm . Other counties were scheduled for coal prohibition in 1995 to 2003, but production nearly ceased in 1991. One report alleged 4,000 deaths per year from the problem. There are typically 29,000 deaths in all Ireland each year. Funding of the report was from governmental environmental agencies, including the US. The Lancet’s acceptance of such a report reflects badly on editorial decisions and review processes. It may also show cultural stereotypes. I can’t imagine the retired editor, Ian Munro, accepting such a report.

US coal use in 1990 was over 4 tons per person. Picture the difference in exposure to combustion products, including sulfur dioxide, whose level has been falling steadily in US air. http://www.epa.gov/airtrends/sulfur.html Coal should clearly not be used in areas subject to inversions or that are regularly arid. All forms of energy used in electrical production have negatives, hydroelectric probably the least. Per capita reductions in electrical consumption are important and regularly seen. Fictitious problems don’t help the situation.

 

[vanesch]

Off the top of my head they cite surface albedo changes from ice cover losses as one of the other feedbacks.

Sure. But in how much that explains the overall effect is to be seen, because the ice cover is in the lowly exposed parts of the earth. Also, it is not clear in how much there is a strict relationship between global temperature and ice cover for small variations. Changing cloud cover is probably a more important factor. There is also biological feedback: more heat and more CO2 should change the natural plant cover, and have an influence on albedo. But I'm not contradicting that these feedbacks aren't possible. I'm just pointing out that (at least I didn't find it in the IPCC report) this has not been modeled entirely beyond doubt in agreement with all the rest.

 

[vanesch]

These are the people who give us all our fuel rod “swimming pools” that I believe contribute to our rising temperatures on the Northern third of the planet (#3 Nuclear…)

Eh, I don't understand what you are at. Spend fuel pools are contributing to global warming ?? Is that what you say ?

 

[DEMcMillan]

Eh, I don't understand what you are at. Spend fuel pools are contributing to global warming ?? Is that what you say ?

The cited thread has my August 1 posting about the nuclear waste problem. It is surrounded by reflex secrecy, hence the numbers are all guesses. Water vapor is clearly the most important greenhouse gas. Things that increase its entry into the atmosphere contribute to global warming by this means. For the fuel rods, direct heat contributions count as well.

 

[Andrew Mason]

As such, the atmosphere (and even the vacuum) act as a kind of "resistor" in which a radiant flux is driven by temperature differences.

Conduction and convection are driven by temperature differences. Radiation is driven by temperature of the radiating body. A body at thermal equilibrium with its surroundings will not conduct or convect heat. But it will still radiate.

No \Delta T is needed to cause a body to radiate. The temperature gradient in the atmosphere is caused by gravity (causing decreasing density which reduces heat capacity and heat conduction) and by the distance from the heat source (the surface). The gradient should have no bearing on the amount of out-radiation from the atmosphere.

As such, we can think of heat to "make its way" through the atmosphere, and needing an extra "delta-T" each time it crosses a layer of atmosphere.

But you have to take into account whether the atmosphere absorbs IR radiation.

If the atmosphere is transparent to IR radiation (ie no GHGs) the out-radiation from any part of the atmosphere (due the atmosphere is heated by conduction and convection) will go into space. It is only by introducing GHGs does it get complicated.

Let's assume there are no GHGs in the atmosphere. All radiation from the sun reaches the surface and warms it. There is no warming of the atmosphere by the incoming radiation from the sun or from the outgoing radiation from the surface. The atmosphere warms only through conduction and convection. The warmed atmosphere provides more out-radiation than if it were not warmed.

The heat from the outward radiation from the Earth and atmosphere must be equal to the incoming radiation from the sun. So the conduction and convection of heat from the surface to the atmosphere, which necessarily increases the out-radiation from the atmosphere, must lead to a decrease in out-radiation from the surface - meaning the surface must be cooler than if there was no atmosphere. The amount of such decrease depends on how much heat is transferred to the atmosphere by conduction/convection.

BUT, suppose the atmosphere absorbs IR radiation. Everything changes.

Now, not all of the out-radiation from the surface or from the atmosphere reaches space. This means that the temperature of the atmosphere must increase so that the out-radiation from the surface + atmosphere LESS the absorbed out-radiation is equal to the total incoming radiation. This necessarily means that the temperature of the surface and atmosphere must increase until the additional out-radiation is equal to the radiation absorbed by the atmosphere.

It is quite easy to see why Venus, with 95% CO2 in its atmosphere making it essentially opaque to IR radiation, has such a high surface temperature.

AM

 

[vanesch]

The cited thread has my August 1 posting about the nuclear waste problem. It is surrounded by reflex secrecy, hence the numbers are all guesses. Water vapor is clearly the most important greenhouse gas. Things that increase its entry into the atmosphere contribute to global warming by this means. For the fuel rods, direct heat contributions count as well.

Eh, that sounds crazy. The *direct heat contribution* ? The total power of spend fuel after a few years is about 2 KW per ton of spend fuel, and after 50 years, about 500 W. In the whole world, there is about 200 000 ton of spend fuel, so if we take an average of 1 KW, we have 200 MW of spend heat from fuel, and that's heating the planet ?? The forcing by this must be less than a nanowatt per square meter.

 

[vanesch]

A body at thermal equilibrium with its surroundings will not conduct or convect heat. But it will still radiate.

No \Delta T is needed to cause a body to radiate.

Actually, there is: it is the delta T between the body "receiving the heat" and the body "emitting the heat". The relationship is not linear. But the transfer of heat between two black or grey bodies by radiation is driven by their temperature difference. Two bodies at the same temperature don't exchange heat through radiation either (or better, exchange heat in exactly the same amounts so that the balance is 0, just as with conduction).

The temperature gradient in the atmosphere is caused by gravity (causing decreasing density which reduces heat capacity and heat conduction) and by the distance from the heat source (the surface). The gradient should have no bearing on the amount of out-radiation from the atmosphere.

The temperature gradient is determined by the heat transport processes (conduction, convection, radiation) and the properties of the gasses (absorption etc...). The pressure gradient is determined by gravity, and convection also, as a function of the temperature gradient and the hydrodynamic properties of the fluid (density, viscosity, ...)

If the atmosphere is transparent to IR radiation (ie no GHGs) the out-radiation from any part of the atmosphere (due the atmosphere is heated by conduction and convection) will go into space. It is only by introducing GHGs does it get complicated.

Let's assume there are no GHGs in the atmosphere. All radiation from the sun reaches the surface and warms it. There is no warming of the atmosphere by the incoming radiation from the sun or from the outgoing radiation from the surface. The atmosphere warms only through conduction and convection. The warmed atmosphere provides more out-radiation than if it were not warmed.

The point is that if the atmosphere doesn't absorb ANY IR radiation, then it cannot radiate it away either ("white body"). That's Kirchhoff's law.

The heat from the outward radiation from the Earth and atmosphere must be equal to the incoming radiation from the sun. So the conduction and convection of heat from the surface to the atmosphere, which necessarily increases the out-radiation from the atmosphere, must lead to a decrease in out-radiation from the surface - meaning the surface must be cooler than if there was no atmosphere. The amount of such decrease depends on how much heat is transferred to the atmosphere by conduction/convection.

Well, that's not true, because of Kirchoff's law. The Earth surface cannot be cooler with an atmosphere than without it.

BUT, suppose the atmosphere absorbs IR radiation. Everything changes.

Now, not all of the out-radiation from the surface or from the atmosphere reaches space. This means that the temperature of the atmosphere must increase so that the out-radiation from the surface + atmosphere LESS the absorbed out-radiation is equal to the total incoming radiation. This necessarily means that the temperature of the surface and atmosphere must increase until the additional out-radiation is equal to the radiation absorbed by the atmosphere.

That's the greenhouse effect. I agree of course with that. What I'm saying, is that the presence of convection is an extra heat transport phenomenon, which might decrease a bit the greenhouse effect as compared to a similar atmosphere but where there is no convection and the transport is ONLY by radiation. So convection is a negative feedback mechanism to the "purely optical" greenhouse effect.

 

[bellfreeC]

Re:1964866, 1947839, 1955447 --

>> The CO2 problem is an insulation not an insolation problem. <<
Why is it not both?


>> The question is: what is the surface temperature at Earth's thermodynamic equilibrium? <<
Life doesn't have an equilibrium, does it? I mean it is hard to define; explain even.


>> A greenhouse can use many different techniques for regulating and/or storing heat. These do not illustrate the greenhouse principle. <<
They do.
May I introduce "the atmospheric window" to this illustrious forum?!

MrB.

PhysOrgForum Science, Physics and Technology Discussion Forums ...This diagram shows an infrared power of 40 Watts per square metre of surface for
photons in the atmospheric window going straight out to space. ...
http://www.physforum.com/index.php?showtopic=7157&st=45 - 77k - Cached - Similar pages

PhysOrgForum Science, Physics and Technology Discussion Forums ...is to believe that an atmospheric window does not exist all the way to the
surface! ___-----______---- Sunlight falling on a white glacier surface
strongly ...
http://www.physforum.com/index.php?showtopic=19006&st=30 - 90k - Cached

 

[Andre]

It appears that this thread goes round in circles, repeating elements again. Isn't it time to concentrate on the available evidence to see what is supported?

 

[bellfreeC]

Andre Jan23-07 04:03 PM

------------------------------------------------------

Ah, the emperor wears clothes.

Try these for a change:

http://www.phys.huji.ac.il/shaviv/articles/sensitivity.pdf
http://www.knmi.nl/~laatdej/2006joc1292.pdf
http://adsabs.harvard.edu/abs/2006MAP...tmp...16Z
http://en.rian.ru/russia/20070115/59078992.html
http://pubs.acs.org/cgi-bin/abstract.cgi/enfuem/2006/20/i03/abs/ef050276y.html

When experts keep telling that they are right because the models say so then they have abandoned the scientific method and hence rely on autority.

-------------------------------------
That was from thread 152617.
I tried the Russian link yesterday [11/20/08].
http://en.rian.ru//russia/20070115/59078992-print.html

"However, scientists acknowledge that rises in temperatures can potentially cause massive increases of greenhouse gases due to various natural positive feedback mechanisms, for example the methane released by melting permafrost, ocean algae's reduced capacity to absorb carbon at higher water temperatures, and the carbon released by trees when forests dry up.

Abdusamatov, a doctor of mathematics and physics, is one of a small number of scientists around the world who continue to contest the view of the IPCC, the national science academies of the G8 nations, and other prominent scientific bodies."

And I arrived at that thread this way:

Global warming causality Text - Physics Forums Library2. CO2 and Global Warming Might be an idea to check out Svensmark, H. 2007.
Cosmoclimatology: a new theory emerges. Astronomy & Geophysics 48: 1.18-1.24.
...
https://www.physicsforums.com/archive/index.php/t-152617.html - 91k
Results 1 - 12 of about 12 for svensmark OR cosmoclimatology site:www.physicsforums.com.

(The "atmospheric window" did not show-up in Google's search of this website. It should now, of course... in due time!)

The reason for that search is post #60 of this current thread[204120].

Andrew Mason Nov2-08 10:24 PM

------------------------------------------------------------------------------

Re: Global warming is not caused by CO2

Quote:

---------
Originally Posted by Andre (Post 1936501)
Well, you probably know the routine: refute it, challenge Al Gore and me scientifically. Do everything possible to demonstrate one to be wrong. It's not that difficult.


Same story I would say, albeit that global and local effects both of CO2 and CH4 will be eye-openers in the first place, once examined thoroughly.

------------------------------------------------------------------

So far, no one has been able to establish one fact that is inconsistent with increased CO2 concentrations causing the average temperature of the surface of the Earth to increase, nor with the increased CO2 concentrations being generated directly or indirectly by human activity.

But that is not enough. To prove that the average temperature of the surface of the Earth is increasing due to concentrations of CO2 which result from human activity, one has to show that there are facts which are inconsistent with all other reasonable alternative explanations.

So what are those other reasonable alternative explanations? So far as I can tell, they are:

1. that the solar cycle is causing the Earth's surface to warm. In other words, the radiation energy output of the sun has increased.

2. that the increase in CO2 concentration is due to natural causes ie. causes which are not due to human activity, such as volcanic eruptions.

3. that the Earth is undergoing cyclical temperature change due to the change in the angle of the Earth to the sun due to precession of the Earth's axis of spin

4. that there is no increase in CO2 concentration at all. The problem is that the record keeping prior to the 1950's is poor and analysis of ice layers in glaciers is inaccurate.

Are there any others?

AM


Maybe, the modification of one... the electromagnetic "output of the sun has increased" disallowing more cosmic rays in doing untold{or not well told!} damage to the carbon dating method.
In regards to AGW, it dismisses it. This ten year old hypothesis says cloud cover is increased with lower solar output and higher cosmic ray input.
Clouds are king. This is especially true when compared to methane, a parts per _billion_ trace gas. Methane has the analogy of a screen over the atmospheric window whereas carbon dioxide squishes it shut a little. And it might be very little(depending on the saturation argument)!

MrB.

 

[Phrak]

I continually hear echoes of the notion that the IPCC is anything but an arm of a political organization with a political agenda. The conclusions ostensibly reached by the IPCC panel are those desired by the facilitator. The panel itself is required by the UN to provide window dressing. The corruption of the IPCC as a scientific body to full-blown political entity is a matter of historical record. Science lost; Globalism won.

The following is an especially revealing article because it was written by one scientist on the 1995 panel, who sold-out under pressure and writes in an attempt to rationalize his actions. He wishes we should label him as "courageous" (See the section An Open Process of Scientific Debate).

http://www-personal.si.umich.edu/~pne/PDF/ecofables.pdf"

----------------------------------------------------------------------------------
coming at you from a world where the weight of the evidence is ignored in favor of the gravity of the charges.

 

[vanesch]

I just want to remind everybody that we want to keep the discussion entirely on the scientific side. Especially conspiracy theories are not welcome here. If you have arguments, it should be technical and scientific.

 

[Phrak]

I just want to remind everybody that we want to keep the discussion entirely on the scientific side. Especially conspiracy theories are not welcome here. If you have arguments, it should be technical and scientific.

Excuse me? Was that directed at me? When I read a paper, I want to know who reviewed it, who published it, and who wrote it. To disregard the human element makes little sense.

And what of the facts? These are presented in the above article, where the agreed-upon conclusions of the IPCC panel were changed in the summary, by the facilitator, without making these changes known to the participants. On discovery, above the objections of the panel members, the summary stood.

You may call this a conspiracy if you like. Making the accusation is a personal attack intended to discredit an opponent in a debate, rather than address the argment itself.

 

[vanesch]

Excuse me? Was that directed at me? When I read a paper, I want to know who reviewed it, who published it, and who wrote it. To disregard the human element makes little sense.

And what of the facts? These are presented in the above article, where the agreed-upon conclusions of the IPCC panel were changed in the summary, by the facilitator, without making these changes known to the participants. On discovery, above the objections of the panel members, the summary stood.

You may call this a conspiracy if you like. Making the accusation is a personal attack intended to discredit an opponent in a debate, rather than address the argment itself.

In this thread we are discussing the mechanisms by which CO2 might have a strong warming effect. We are not discussing of whether the IPCC is a corrupt institution. If you would have read more of my contributions, you would BTW know that I cannot be said to be a strong defender of their scientific attitude either. But we are not discussing that by itself here and the Earth forum is not the place for it. If you want to talk about the study of how human relations affect publications, and you have some material, this might be posted in the social sciences forum. If you have a political statement to make, you can do that in the politics forum. But we don't do conspiracy theories here (even if they are true, I'd say). We don't care about who did what in the IPCC honestly. We try to discuss the mechanisms by which CO2 can heat or not, the earth, based upon measurements and calculations and so on. Not about who said what, and who was told to shut up.

Don't get me wrong. I'm not saying that you are right or wrong. I'm not expressing any value judgement about what you have to say. I'm only saying that this is not the place to say it.

 

[baywax]

Am I right to say that you get a "nuclear winter" when there's particulate floating in the atmosphere, blocking the sun's rays? Is this similar to what CO2 can do... such as the brown sludge cloud that is migrating around the globe?

While, at the same time, people are saying that heat is trapped(?) by CO2 in the atmosphere or is absorbing heat and so warming the globe?? Its pretty confusing to the lay climatologist like me.

 

[mheslep]

Am I right to say that you get a "nuclear winter" when there's particulate floating in the atmosphere, blocking the sun's rays? Is this similar to what CO2 can do... such as the brown sludge cloud that is migrating around the globe?

While, at the same time, people are saying that heat is trapped(?) by CO2 in the atmosphere or is absorbing heat and so warming the globe?? Its pretty confusing to the lay climatologist like me.

Particulate matter and aerosols block incoming radiation, CO2 effectively blocks outgoing long(er) wave re-radiation from the surface. The trick is in determining the amount of each, and their couplings to other means of heat transfer.

https://www.physicsforums.com/showthread.php?t=223362&referrerid=70823"

 

[baywax]

Particulate matter and aerosols block incoming radiation, CO2 effectively blocks outgoing long(er) wave re-radiation from the surface. The trick is in determining the amount of each, and their couplings to other means of heat transfer.

https://www.physicsforums.com/showthread.php?t=223362&referrerid=70823"

Thank you for the link to the Nuke Winter thread. I get the difference, to a degree ().

 

[wolram]

Read this right or wrong, but is there no test for the reflectivity of the atmosphere? for sure one could send a beam of light from the ground and test how much escapes to space, and at the same time measure ground teperature ,that would give a localised measure?

 

[mheslep]

Read this right or wrong, but is there no test for the reflectivity of the atmosphere? for sure one could send a beam of light from the ground and test how much escapes to space, and at the same time measure ground teperature ,that would give a localised measure?

As I see it, for that measurement to work CO2 would half to act as a beam splitter or half mirror. It doesn't. CO2 molecules scatter IR radiation in every direction, so there's no way to construct a receiver to collect all of the radiation that diffuses into space.

 

[vanesch]

Read this right or wrong, but is there no test for the reflectivity of the atmosphere? for sure one could send a beam of light from the ground and test how much escapes to space, and at the same time measure ground teperature ,that would give a localised measure?

I would say that the radiation transport problem is the easiest. After all, it is physics. It is true that there are some approximations that are used there, but normally, a program like MODTRAN (see http://en.wikipedia.org/wiki/MODTRAN ) implements a rather straightforward model of the IR radiation transport. I know that there are some publications that put some question marks concerning things like the approximations used in applying the boundary conditions and so on, but I never plunged in all the details. I would think that this is rather mastered on the theoretical side.

An elementary explanation can be found in section 2.2 of the second chapter of the physical basis of the 4th assessment report of the IPCC http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf although they don't explain in any detail how these things are calculated.

The point is that this purely optical transport does give a greenhouse effect, but much smaller than what is claimed by the AGW theory.

As to measurements, look at chapter 3: point 3.4.4 - although I have to say I didn't look into this in much detail.

 

[Andrew Mason]

Actually, there is: it is the delta T between the body "receiving the heat" and the body "emitting the heat". The relationship is not linear. But the transfer of heat between two black or grey bodies by radiation is driven by their temperature difference. Two bodies at the same temperature don't exchange heat through radiation either

Why not? Why would one stop radiating just because another body at the same temperature approaches?

(or better, exchange heat in exactly the same amounts so that the balance is 0, just as with conduction).

Better. But the balance is not really 0. As two radiating bodies at the same temperature approach each other, their temperatures will increase.

The point is that if the atmosphere doesn't absorb ANY IR radiation, then it cannot radiate it away either ("white body"). That's Kirchhoff's law.

I think you are right on that point, but it is complicated. The ability to absorb IR radiation depends on wavelength. Air that does not absorb or emit IR radiation well at a particular wavelength may absorb and emit longer wavelength radiation well. So as the air cools, it may become more efficient at emitting radiation. Since air will have a more moderate temperature than the surface, the heat conducted into the air and convected up will radiate at a lower wavelength than the IR radiation given off by the surface.

AM

 

[Andre]

Better. But the balance is not really 0. As two radiating bodies at the same temperature approach each other, their temperatures will increase.

Really, which law is that? Not Kirchhoff I think; but where is the additional energy coming from?

 

[vanesch]

Why not? Why would one stop radiating just because another body at the same temperature approaches?

I didn't say that they would stop radiating: I said that the *heat transfer* between both is going to stop, in that the net flow of heat from one to the other is going to be zero.

Better. But the balance is not really 0. As two radiating bodies at the same temperature approach each other, their temperatures will increase.

Not if the cause of their thermal radiation is exactly their temperature. If they have an internal process which is the cause of the radiating (like a chemical reaction or so going on, or a nuclear reaction, or whatever), yes of course, because they partly or entirely block each other's cold sky. But when I put two black marbles of the same temperature close to one another, they don't get hotter, you know

I think you are right on that point, but it is complicated. The ability to absorb IR radiation depends on wavelength. Air that does not absorb or emit IR radiation well at a particular wavelength may absorb and emit longer wavelength radiation well. So as the air cools, it may become more efficient at emitting radiation.

Since air will have a more moderate temperature than the surface, the heat conducted into the air and convected up will radiate at a lower wavelength than the IR radiation given off by the surface.

AM[/QUOTE]

 

[mheslep]

I would say that the radiation transport problem is the easiest. After all, it is physics. It is true that there are some approximations that are used there, but normally, a program like MODTRAN (see http://en.wikipedia.org/wiki/MODTRAN ) implements a rather straightforward model of the IR radiation transport. I know that there are some publications that put some question marks concerning things like the approximations used in applying the boundary conditions and so on, but I never plunged in all the details. I would think that this is rather mastered on the theoretical side.

An elementary explanation can be found in section 2.2 of the second chapter of the physical basis of the 4th assessment report of the IPCC http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf although they don't explain in any detail how these things are calculated.

The point is that this purely optical transport does give a greenhouse effect, but much smaller than what is claimed by the AGW theory.

As to measurements, look at chapter 3: point 3.4.4 - although I have to say I didn't look into this in much detail.

Yes we can model it, but is there any way to actually measure IR blockage in a section of the troposphere, bottom to top? One could, say, use a ground based IR laser to target a receiving aircraft or satellite to simulate surface radiated IR. That would only measure the percent of transmitted IR. But then one couldn't say what happened to the rest of the beam, nor attribute the lost energy to a particular greenhouse gas, water vapor, CO2, whatever.

 

[Andrew Mason]

I didn't say that they would stop radiating: I said that the *heat transfer* between both is going to stop, in that the net flow of heat from one to the other is going to be zero.

It is a semantic point, perhaps. Since we start with a constant flow of energy (radiation) out that is determined by the temperature of the black body, if you have an additional inflow of radiation energy from a black body situated nearby at the same temperature, there is heat transfer to the first. The energy from the first intercepted by the second may be equal to the energy received by the first from the second, but there is definitely an exchange of energy.

Not if the cause of their thermal radiation is exactly their temperature. If they have an internal process which is the cause of the radiating (like a chemical reaction or so going on, or a nuclear reaction, or whatever), yes of course, because they partly or entirely block each other's cold sky. But when I put two black marbles of the same temperature close to one another, they don't get hotter, you know

If we are talking about a blackbody in thermal equilibrium, there has to be a constant source of input energy. Otherwise it keeps getting colder as it radiates. If you move two such objects closer to each other, the temperature of each will rise. If you take two black marbles at the same temperature at distant separation in a vacuum they will cool at the same rate by radiation. If you bring them closer together, they won't get warmer but they will cool at a slower rate.

I think you are right on that point, but it is complicated. The ability to absorb IR radiation depends on wavelength. Air that does not absorb or emit IR radiation well at a particular wavelength may absorb and emit longer wavelength radiation well. So as the air cools, it may become more efficient at emitting radiation. Since air will have a more moderate temperature than the surface, the heat conducted into the air and convected up will radiate at a lower wavelength than the IR radiation given off by the surface.

Have a look at http://www.atmos.umd.edu/~owen/CHPI/IMAGES/transir.html" showing the absorption of IR radiation by different gases as a function of wavelength.

Having an atmosphere that will not trap IR radiation definitely cools the surface locally because it removes heat from the local surface. If all it does is redistribute that heat over the entire surface, it will have a moderating effect rather than a net cooling effect. So parts of the Earth would be much hotter and parts would be much colder without the atmosphere - similar to the moon.

AM

 

[bellfreeC]

>> Results 1 - 12 of about 12 for svensmark OR cosmoclimatology <<

Hey, another twelve...
Results 1 - 12 of about 12 for hitran.
I will list the most exciting(in relation to this thread\questions)
and then the scary part from my own archives.


CO2 saturation point?
MODTRAN here is a basic mathematical tool to calculate radiation profiles in
certain kinds of atmosphere, using the HITRAN database. ...
https://www.physicsforums.com/showthread.php?t=231437 - 93k - Cached - Similar pages

Lasers Text - Physics Forums Library
Modtran is a wonderful program for simulating transmittance through the
atmosphere google Modtran and Hitran. Redbelly98. Apr17-08, 09:31 PM ...
https://www.physicsforums.com/archive/index.php/t-225471.html - 15k - Cached -

Global warming case frustrating Text - Physics Forums Library
One does need to have good information on molecular absorption - such as the hitran database. Care should be taken to make sure proper resolution and ...
https://www.physicsforums.com/archive/index.php/t-174215.html - 26k - Cached -

CO2 saturation point? Text - Physics Forums Library...
basic mathematical tool to calculate radiation profiles in certain kinds of atmosphere, using the HITRAN database (http://cfa-www.harvard.edu/hitran/). ...
https://www.physicsforums.com/archive/index.php/t-8259.html %253Cbr%2520/t-231437.html - 22k -


Radiative transfer to space affected by atmosphere? Text - Physics
...The atmospheric absoprtion depends on pretty much everything, there's good
computational models (LOWTRAN/MODTRAN/HITRAN) out there, some of which are public ...
https://www.physicsforums.com/archive/index.php/t-220110.html - 7k - Cached -

Observations About Global Circulation Models
Therefore collisionnaly induced emissions/absorptions (and no it is neither 0 nor negligible) are ignored because they are not in Hitran . ...
https://www.physicsforums.com/showthread.php?t=214063 - 37k - Cached -



In the interview below, in-cites correspondent Gary Taubes talks with Dr. Laurence Rothman of the Harvard-Smithsonian Center for Astrophysics about his highly cited paper,
[HITRAN stands for HIgh-resolution TRANsmission molecular absorption database, and it goes all the way back to 1961...]
"The HITRAN molecular spectroscopic database and HAWKS (HITRAN Atmospheric Workstation): 1996 edition"
...
What’s been the biggest surprise over the last 40 years?

'Well, one of them is how many things man is putting up there. It makes my job never-ending. I just added a new molecule to the database that I can’t even pronounce. It gets a little strange. We have all these new gasses that replace CFCs, which attack the ozone, but the new gasses are long-lived and have other effects. They become greenhouse gasses. The only solution is to have fewer humans."

In addition, in regards to the chart;
http://www.atmos.umd.edu/~owen/CHPI/IMAGES/transir.gif
Andrew linked, you can clearly see the "shoulder" for CO2 and which way the window shuts.
MrB.

How accurate are the HITRAN measurements?

We require these things, because of the instrumental capabilities of NASA satellites, to have incredible accuracy. That means we want to know line positions to one part in 10 million or even better. That’s a tough demand. We want to know the intensities to better than two percent. That’s tough, too. There are so many sources of error. For example, the pressure and the temperature in the cells that we’re using to measure these quantities. We’re pushing the envelope.

 

[Phrak]

In this thread we are discussing the mechanisms by which CO2 might have a strong warming effect. We are not discussing of whether the IPCC is a corrupt institution. If you would have read more of my contributions, you would BTW know that I cannot be said to be a strong defender of their scientific attitude either. But we are not discussing that by itself here and the Earth forum is not the place for it. If you want to talk about the study of how human relations affect publications, and you have some material, this might be posted in the social sciences forum. If you have a political statement to make, you can do that in the politics forum. But we don't do conspiracy theories here (even if they are true, I'd say). We don't care about who did what in the IPCC honestly. We try to discuss the mechanisms by which CO2 can heat or not, the earth, based upon measurements and calculations and so on. Not about who said what, and who was told to shut up.

Don't get me wrong. I'm not saying that you are right or wrong. I'm not expressing any value judgement about what you have to say. I'm only saying that this is not the place to say it.

You like the word 'honestly.' You have multiple points of--shall I call them errors?--throughout your responses to me. They've been bothering me a great deal. Perhaps you'd like to restate yourself.

 

[vanesch]

You like the word 'honestly.' You have multiple points of--shall I call them errors?--throughout your responses to me. They've been bothering me a great deal. Perhaps you'd like to restate yourself.

Yes, I will restate myself: keep to the scientific discussion of the thread here, and not about the political, sociological and other considerations, for which there are other forums. Is that clear enough ?

 

[vanesch]

It is a semantic point, perhaps. Since we start with a constant flow of energy (radiation) out that is determined by the temperature of the black body, if you have an additional inflow of radiation energy from a black body situated nearby at the same temperature, there is heat transfer to the first. The energy from the first intercepted by the second may be equal to the energy received by the first from the second, but there is definitely an exchange of energy.

Yes. I was thinking of "heat transfer" as the NET balance. Of course at equal temperature there are still photons going from A to B and photons from B to A, but the net heat flow is 0.
I guess we agree upon that. What actually counts, is the net heat flow through the atmosphere (which, as you said, must be fixed, as given by the solar influx minus albedo). The question is, what is the needed temperature of the surface to obtain this heat transfer through the atmosphere.

If we are talking about a blackbody in thermal equilibrium, there has to be a constant source of input energy. Otherwise it keeps getting colder as it radiates. If you move two such objects closer to each other, the temperature of each will rise. If you take two black marbles at the same temperature at distant separation in a vacuum they will cool at the same rate by radiation. If you bring them closer together, they won't get warmer but they will cool at a slower rate.

Sure.

Have a look at http://www.atmos.umd.edu/~owen/CHPI/IMAGES/transir.html" showing the absorption of IR radiation by different gases as a function of wavelength.

I know, I'm not disputing that. What I'm saying is that the required delta-T for a certain net heat flow outward of an atmosphere will be smaller if there is a strong convection, than if not. That's all.

The reason for that is that the convection is an EXTRA heat transport mechanism that brings heat from the lower layers to the upper layers, and as such, one needs a smaller effective delta-T than if this extra heat transport mechanism were absent, and the entire heat flow had to go through radiative transport, layer by layer. This radiative transport remains of course valid, but is now a smaller heat flux, given that part of the heat flux goes in the parallel convection path. Smaller radiative heat flux means smaller necessary delta-T.

Having an atmosphere that will not trap IR radiation definitely cools the surface locally because it removes heat from the local surface. If all it does is redistribute that heat over the entire surface, it will have a moderating effect rather than a net cooling effect. So parts of the Earth would be much hotter and parts would be much colder without the atmosphere - similar to the moon.

Well, redistribution will change the local heat fluxes (although, I agree, the total heat flux is fixed and given by the sun incoming radiation), and this will mean different local delta-T. It is not clear that the average of the delta-T with, and without redistribution should be the same.

For instance, BB radiation goes in T^4. So a body that has very hot, and very cold surfaces, will radiate away much more radiation than a body that has the same average temperature, but uniformly distributed. The reason is that 5 degrees more will give rise to somewhat more radiation, than what is missing with 5 degrees less. It is due to the non-linear T dependence.
In other words, all else equal, you will have a higher average temperature when you "mix well", than when you "heat locally".

 

[Bystander]

(snip)If we are talking about a blackbody in thermal equilibrium, there has to be a constant source of input energy. Otherwise it keeps getting colder as it radiates. If you move two such objects closer to each other, the temperature of each will rise. If you take two black marbles at the same temperature at distant separation in a vacuum they will cool at the same rate by radiation. If you bring them closer together, they won't get warmer but they will cool at a slower rate.

(snip)

NO! NO! NO!

Kirchoff's Law! Review it! Understand it! The third blackbody you introduce in this statement (vacuum --- without a temperature specification) is the temperature bath with which your two black bodies are in equilibrium. There is no net exchange of energy among the three, and no temperature change. If you wish to equilibrate two black bodies originally at the same, higher temperature than CMB with intergalactic space, the rate of cooling can be reduced by whatever fraction of 4 pi steradians each subtends of the other's exposure to the CMB background temperature bath.

You keep taking the first step of the random walk Gamow treats in very simplified fashion for energy transport from the center of the sun to the solar surface; take the rest of the trip --- a "photon" (or the equivalent energy) proceeds by "the drunkard's walk" from the center of the sun to its surface in a time of the order of thousands of years, and you may conclude that infrared proceeds from Earth's surface to space by the same "drunkard's walk," and if you do the calculation you'll find an order of magnitude for "residence time" for this "excess greenhouse energy."

This silly thread has been going on and on and around and around in circles. Results of transmission measurements discussed independently of emissivities aren't going to get anyone anywhere --- let's all do all the applicable physics together at one time, just once, shall we?

 

[vanesch]

N If you wish to equilibrate two black bodies originally at the same, higher temperature than CMB with intergalactic space, the rate of cooling can be reduced by whatever fraction of 4 pi steradians each subtends of the other's exposure to the CMB background temperature bath.

Yes, I guess that was what Andrew was after.

You keep taking the first step of the random walk Gamow treats in very simplified fashion for energy transport from the center of the sun to the solar surface; take the rest of the trip --- a "photon" (or the equivalent energy) proceeds by "the drunkard's walk" from the center of the sun to its surface in a time of the order of thousands of years, and you may conclude that infrared proceeds from Earth's surface to space by the same "drunkard's walk," and if you do the calculation you'll find an order of magnitude for "residence time" for this "excess greenhouse energy."

Indeed. That's the "radiation resistance" you have there: the radiative transfer, layer by layer, of heat energy in the form of photons, converted into molecular motion/excitation/..., and again into photons etc...
The point I tried to make was that having solely radiative heat transport will require a higher source surface temperature, than if you add convection next to the radiative transfer, because convection will transport part of the heat (and hence diminish the required heat flux by radiative transport). This comes down to saying that convection is an extra heat transport mechanism which will give rise to a lower rise in surface temperature as compared to when there would be no convection. However, I admit not having any idea by how much, but I'm pretty sure about the *sign* of the contribution (namely, negative).

 

[Andrew Mason]

NO! NO! NO!

Kirchoff's Law! Review it! Understand it! The third blackbody you introduce in this statement (vacuum --- without a temperature specification) is the temperature bath with which your two black bodies are in equilibrium.

In my example, the two blackbodies are not in thermal equilibrium with a third blackbody. Since their temperatures are constant, the rate of energy input is equal to the rate of energy output. There has to be input energy from some energy source for this to occur, but that need not be a third blackbody.

We assume that Earth is in thermal equilibrium ie. its temperature does not change. This is not true over a short period of time, but it is generally true over a long period of time. All this means is that the rate of energy input equals the rate of energy output. We will ignore the energy input that is stored in the Earth in a form other than heat, so energy output is deemed to be all in the form of radiation into space. Energy input is from various sources: sun, moon, stars, CMB, cosmic rays, Earth's internal core.

There is no net exchange of energy among the three, and no temperature change.

I don't understand what you are saying. What are the three bodies? One cannot be in thermal equilibrium with space. Space, by definition, is devoid of matter so it cannot have a temperature. The rate of outradiation of the blackbody is greater than the incoming CMB radiation. .

If you wish to equilibrate two black bodies originally at the same, higher temperature than CMB with intergalactic space, the rate of cooling can be reduced by whatever fraction of 4 pi steradians each subtends of the other's exposure to the CMB background temperature bath.

You keep taking the first step of the random walk Gamow treats in very simplified fashion for energy transport from the center of the sun to the solar surface; take the rest of the trip --- a "photon" (or the equivalent energy) proceeds by "the drunkard's walk" from the center of the sun to its surface in a time of the order of thousands of years, and you may conclude that infrared proceeds from Earth's surface to space by the same "drunkard's walk," and if you do the calculation you'll find an order of magnitude for "residence time" for this "excess greenhouse energy."

We aren't concerned with the residence time of photons in the sun. We are only concerned with its energy output. Since the temperature of the sun is fairly constant we conclude that the energy input (from fusion in its core) is equal to its energy output.

AM

 

[DEMcMillan]

Originally posted by Bystander:

This silly thread has been going on and on and around and around in circles. Results of transmission measurements discussed independently of emissivities aren't going to get anyone anywhere --- let's all do all the applicable physics together at one time, just once, shall we?

This thread has covered a lot of ground and is now able to consider its title. I will put forward an estimate of the scale of the CO₂ contribution for others to consider and increase or reduce in scale, based upon Bystander’s emissivity theme. I estimate that the effect of the 14% CO₂ rise over the last 30 years is 0.05 + 0.01 ^oC. I submit that the use of HITRAN CO₂ data requires information about local difference in upward and downward longwave flux for its implementation. The line by line models being used, including Modtran, use a balancing system of optical depth and spectrum-wide compensating gray scale to estimate photon scattering back to the surface. The atmosphere radiates on the basis of its temperature, like all other matter. I have pointed out elsewhere that analytical chemistry of stratosphere gases utilizes a program that requires emissivity estimation and “black body” or 1.0 is used. https://www.physicsforums.com/showthread.php?t=261966 . The upper stratosphere (50km, 1mPa) is much warmer than any tropospheric area above 6 km altitude. Therefore it should contribute more to downward longwave radiation than anything but clouds and ground-related inversions (see Andre’s graph on the above thread). Interest in cloud effects has generated measurements of downward longwave radiation. Antarctic data from NCEP/NCAR revisions in figure 2b of http://psc.apl.washington.edu/zhang/Pubs/Zhang_Antarctic_20-11-2515.pdf shows the average was 223 W/m2, a value clearly higher than the outward radiation level of the Antarctic continent. This means that all greenhouse gases will lower temperature by scattering IR photons into space. I added a review of Hansen’s CO₂ doubling estimates and a 69% lowering of his numbers by 50 km earthward radiation equal in emissivity to the surface and now use a nonlinear 14% to lower his current estimate to 0.05 ^oC. I recall an Antarctic IR spectrum showing a positive 13-18 μ peak to support my model but can’t find it. Can anyone help?

 

[Bystander]

(snip)I estimate that the effect of the 14% CO₂ rise over the last 30 years is 0.05 + 0.01 ^oC. I submit that the use of HITRAN CO₂ data requires information about local difference in upward and downward longwave flux for its implementation. The line by line models being used, including Modtran, use a balancing system of optical depth and spectrum-wide compensating gray scale to estimate photon scattering back to the surface.(snip)

Like that --- yeah. And from "scattering back to the surface" it's easy enough to segue back to "random walk/drunkard's walk." The hope was that someone was going to apply Gamow's random walk treatment to the Earth's atmosphere (pick a total path length, mean free path per step) and come up with a "residence time" for energy "trapped" by CO₂ IR bands, multiply that time by the surface radiation flux, divide by atmospheric heat capacity, and come up with an upper limit for the "radiative greenhouse" effect. No such luck --- it's on the order of seconds (single digit seconds --- to maybe 10s if we throw in relaxation times), and is measured in mK at the bottom line. Compare that time to the week, 10 days, 2 weeks implicit in the 30 K "atmospheric greenhouse" we're seeking, and recall the "week, 10 days, 2 weeks" time scales thrown around for atmospheric convection cells, atmospheric residence time of water in the hydrologic cycle, and examine the possibility that there are other mechanisms for retaining the energy associated with a 30 K greenhouse than "clipping" 5 and 15 micron coupons with carbon dioxide scissors and squirreling them away until they expire.

 

[deboss]

Newbie here. I am but a poor humble engineering student. But I seem to recall a chart displaying a temperature oscillation over thirty year periods, thirty years high, then thirty years low. Being an undergraduate student my primary method of finding things is google which doesn't want to help right now. If someone could find I'd be very appreciative. Anyway if there is a non-year based thermal cycle wouldn't performing an average over our arbitrary ten base wind up skewing the data because we're catching only part of one cycle. If my memory is correct and it is a sixty year full cycle then averaging over a hundred years would include two of one cycle but only one and one third of the other. Would this be an option for the temperature difference reported.