Global warming is not caused by CO2

[vivesdn]

This does not cause cooling. If the outradiation from the atmosphere increases, the temperature of the atmosphere must have increased. So, increased outradiation has to be associated with a temperature increase.

AM

Consider an oven at a given inside temperature. Outoor temperature won't change significantly due to the oven. Between inner and outer walls will exist an stationary temperature gradient as thermal energy flows from the hotter inside to the cooler outside. The thicker the wall, the smaller the gradient, and less heat will be lost.
Now, inside the hard wall or even the vacuum wall (Dewar's flask) you have a coil with some fluid that goes from inside surface to outside surface and comes back on a closed loop. A pump keeps the fluid moving.
For sure you'll have increased the heat flow as you transport the hot fluid in contact with inner surface directly to the outer surface, were it will radiate and transfer far more heat as it will be much hotter than the wall would have been if heat was to travel due to temperature gradient through the wall.

 

[baywax]

Just found this article... they're calling these Brown Clouds a mask for Global Warming because of their reflectivity creating a cooling affect(?)

"Imagine for a moment a three-kilometer-thick band of soot, particles, a cocktail of chemicals that stretches from the Arabic Peninsula to Asia," Achim Steiner, UN undersecretary general and executive director of the program, said during a news conference on the findings.

"All of this points to an even greater and urgent need to look at emissions across the planet, because this is where the stories are linked in terms of greenhouse emissions and particle emissions and the impact that they're having on our global climate," he said.

The brown clouds have darkened 13 cities in Asia, including Beijing, Shanghai, Bangkok, Cairo, Mumbai, New Delhi and Tehran, "dimming" sunlight in some places by as much as 25 per cent.

The brown clouds, produced by the burning of fossil fuels, wood and plants, form particles like black carbon and soot that absorb sunlight and warm the air, enhancing the greenhouse effect.

Scientists, however, said the brown clouds also "mask" the warming impacts of climate change by an average of 40 per cent because they contain particles that reflect sunlight and cool the Earth's surface.

http://ca.news.yahoo.com/s/cbc/081113/world/technology_brown_clouds_1

Yetch.

 

[kasse]

This thread offends people of reason, and should be locked.

 

[Andrew Mason]

Yes, of upper layers in the atmosphere. The point is that convection can change the temperature profile of the atmosphere, and depending on that profile, you have a different radiative balance. That is the same as changing the resistivities in a resistive chain, will change the potential distribution along that chain, and will also change the overall current, for the same overall potential difference.

Certainly convection changes the temperature profile of the atmosphere. It moves heat from the surface to higher up in the atmosphere and reduces the temperature gradient. But convection exists now. It is not caused by the air absorbing IR radiation from the surface. It is caused by air being warmed by contact with the surface. It also does not change the radiative balance. That is determined by the amount of solar energy absorbed by the earth. That changes only with a change in the Earth's emissivity.

My original question was: how does an increase in CO2 increase convection? Or, looking at it another way, how does adding CO2 to the atmosphere increase convection beyond what adding the same amount of nitrogen or oxygen to the air?

AM

 

[Andrew Mason]

Consider an oven at a given inside temperature. Outoor temperature won't change significantly due to the oven. Between inner and outer walls will exist an stationary temperature gradient as thermal energy flows from the hotter inside to the cooler outside. The thicker the wall, the smaller the gradient, and less heat will be lost.
Now, inside the hard wall or even the vacuum wall (Dewar's flask) you have a coil with some fluid that goes from inside surface to outside surface and comes back on a closed loop. A pump keeps the fluid moving.
For sure you'll have increased the heat flow as you transport the hot fluid in contact with inner surface directly to the outer surface, were it will radiate and transfer far more heat as it will be much hotter than the wall would have been if heat was to travel due to temperature gradient through the wall.

I don't follow your analogy. If the energy supplied to the interior of the oven is constant and if the temperature is constant, the amount of energy being removed from the oven has to equal the amount of energy being supplied to the interior of the oven. If you increase the rate at which heat energy is removed, the temperature of the oven will reduce until the rate at which heat is removed exactly equals the rate at which energy is being supplied to the interior of the oven (ie. exactly the same rate as before).

Similarly, the energy which the Earth radiates is determined not by the nature or motion of the atmosphere (assuming there is no change in reflectivity/emissivity), but by the amount of radiation incident upon the Earth (ignoring the heat emerging from the interior of the earth). The total amount of radiation emanating from the Earth is completely independent of convection occurring in the atmosphere or the oceans for that matter. The rate at which energy is radiated from the Earth has to be exactly equal the insolation: the rate of radiation energy incident upon it. If this is not the case, the Earth's temperature would self-adjust until the incoming radiation matched the outgoing radiation.

So increased convection cannot increase the amount of radiation emanating from the earth.

The CO2 problem is an insulation not an insolation problem. If the CO2 concentration of the atmosphere increases, more of the outward IR radiation from the surface is absorbed by the atmosphere and half of that is reradiated back to the surface. This means the surface has to heat up in order to balance outward and total inward radiation. Although the total radiation from the Earth does not change, the temperature at the surface of the Earth has to increase.

AM

 

[vanesch]

My original question was: how does an increase in CO2 increase convection? Or, looking at it another way, how does adding CO2 to the atmosphere increase convection beyond what adding the same amount of nitrogen or oxygen to the air?

I have no idea how CO2 can influence convection all by itself. But what is true is that an increased CO2 content will increase the "opacity" of the atmosphere to IR, and hence as such redistribute absorbed and emitted power fluxes. This can have an influence on the temperature distribution in the atmosphere, which by itself is responsible for the drive behind convection.

But that is not the main point. IMO, the main point is that convection is a negative feedback mechanism (independent of whether there is CO2 or not) for radiative forcing of the surface, in that if the radiative forcing increases, then the surface temperature will also increase, and this will drive more convection, which will allow for a larger heat flux to transit through the atmosphere than when no such convection were present.

You are of course right that the total outward flux must equal the inward solar flux that is not reflected directly as visible light (albedo). So the total outward IR flux is fixed (at fixed albedo), and this, independent of what is the composition, and what are the heat transport mechanisms in the atmosphere. At least in a simple 1D model.

So we know (for fixed albedo) what is going to be the outward radiant IR flux. However, what we are interested in, is the total temperature gradient in the atmosphere needed to obtain that IR radiant flux. This net flux is everywhere going to be the same, at every point in the atmosphere. It will of course be composed of different partial fluxes: a radiant upward flux, a radiant downward flux, heat convection, and heat conduction. But the total balance, at every point in the atmosphere, must equal the same, fixed, outward IR flux. As such, the atmosphere (and even the vacuum) act as a kind of "resistor" in which a radiant flux is driven by temperature differences. For the "vacuum", that "resistor" is simply given by the black body formula: for a certain temperature (difference: with the CMB, but that's neglegible), we have a certain outward radiant flux. The atmosphere adds "resistance" to this: we need a bigger temperature difference to obtain the same radiant flux. That extra resistance is the greenhouse effect. It is due to the partial absorption and re-emission of IR radiation by layers of the atmosphere, which cause also a downward IR flux, and hence we need a higher upward flux to compensate, and arrive at the same net outward flux.

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. The more the atmosphere absorbs, the more delta-T there is, and that's the basis of the extra greenhouse effect due to greenhouse gasses.

Also, these "delta-T"s will influence the temperature differences in the atmosphere itself.

So radiatively speaking, heat gets emitted from the Earth surface, is radiated a bit upward, then a bit downward, then a bit upward again, etc... and makes its way all the way up to the highest layers, where it is eventually emitted in space. The sum of all these final contributions must make up the fixed outward radiant flux. The more opaque the atmosphere, the "more difficult" this outward way is, and the higher the overall delta-T that establishes it. Hence, heating of the surface. Each atmospheric layer is a thermal resistor that increases a bit more the overall thermal resistance of this atmosphere.

But here's my point about convection: if there is a "second way" by which heat can be transported upward through the atmosphere, then it "shunts" part of those resistors. Heat can then, by this second way, reach the higher layers more easily than just by radiation from layer to layer, with each time a partial down radiation. And as such, it will lower the delta-T as compared when there were no such convection.

And now here's my point about feedback. If we look at the purely optical effect of increasing CO2 content of the atmosphere, as calculated by MODTRAN, without altering in any other way 1) the rest of the composition of the atmosphere and 2) any convection or whatever, then we find that for a doubling of the CO2 content, we need to increase the surface temperature by about 0.8K in order to restore the same outward IR flux as before (which, we agree upon, is fixed by the solar influx, and albedo).

Now, if you take it that the atmospheric composition also changes concerning water vapor, and you keep fixed relative humidity (instead of fixed total water vapor), which means that you suppose that at the surface, the wet surface will keep a similar equilibrium as the ratio between partial vapor pressure and temperature in the equilibrium case, but without more cloud formation or convection or anything, then you have, IMO, the maximal possible positive feedback from water vapor. MODTRAN then calculates that you need about 1.5 K surface temperature increase for a CO2 doubling, and the increase in water vapor (due to 1.5 K temperature increase) to have again the same outward IR flux. One would expect the right answer to be somewhere between the two. More water vapor probably means more cloud formation and so on (which increase albedo), but that effect is difficult to quantify. Water vapor is also lighter than air, so this might increase convection (what happens in a cooling tower). This might also decrease the effect of water vapor. Water will not evaporate more than given by the partial pressure equilibrium, so this case is the maximal water vapor feedback. So, without taking into account clouds or convection, according to MODTRAN, a CO2 doubling should result in a surface temperature increase between 0.8K and 1.5K.

Now, convection is a negative feedback which should reduce this needed temperature increase of the surface. I have no idea by how much, but I haven't seen any treatment of this.

But the IPCC talk about an average value of 3 K for CO2 doubling, in an interval of 1.5K to 6K. So there needs to be an extra positive feedback, which is not water vapor, and which is capable to bring this 0.8K to 1.5 K interval or smaller to the 1.5 K to 6 K interval. However, those mechanisms are not really explained. This is where I still have my question marks.

 

[Andre]

My original question was: how does an increase in CO2 increase convection?

Wasn't it mentioned that the Infra red radiative interaction starts in the lowest layers of the atmosphere, at the Earth surface, the primary source of the IR. With more CO2 the lower layers get warmer faster increasing the convection rate.

Also, since the convection is adiabatic it also shows that balancing the temperatures between air parcels by radiation is not a predominant process.

 

[wolram]

This thread offends people of reason, and should be locked.

People of reason should state their reasons why the thread should be locked.

 

[vivesdn]

I don't follow your analogy.

Heat is transferred from inside to the outside through a medium. If the medium is solid, heat is transferred by contact and radiatively layer by layer, creating a T gradient. The greater the gradient the higher the heat flow. But with convection in place, high temperature layers will radiate directly half of its energy to the outside, while in a situation with no convection, lower, high temperature layers will radiate half of its energy to upper layers. So not all of the energy is radiated outwards as upper layers will re-radiate inwards part of the energy

So increased convection cannot increase the amount of radiation emanating from the earth.

It is generally assumed that the temperature decreases at a rate around 2ºC every 300m o 1000 feet. This is the standard atmosphere, based on an standard gradient. But advection and convection have a great impact on this gradient, modifying energy transfer.

 

[mheslep]

...But the IPCC talk about an average value of 3 K for CO2 doubling, in an interval of 1.5K to 6K. So there needs to be an extra positive feedback, which is not water vapor, and which is capable to bring this 0.8K to 1.5 K interval or smaller to the 1.5 K to 6 K interval. However, those mechanisms are not really explained. This is where I still have my question marks.

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

 

[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