A Conversation with an Infrared Radiation Expert

When water vapor in the atmosphere condenses into liquid water and then changes state again and becomes ice, it gives off latent heat for both state changes.
Does that latent heat release follow Stefan-Boltzmann’s radiative equation ?

“The only thing Co2 can do is increase the coupling to space”. Thereby having a cooling effect. Good stuff. I would love to hear what Dr. Lindzen has to say about this. If I am not mistaken, this is what he has been saying.

Excellent dialogue Anthony. I found it quite gripping as it explained quite a lot for me. Many Thanks.

It seems that MC knows the subject matter extremely well. It also seems that he says you cannot be certain what is really going on with IR and CO2 in the atmosphere, despite those who seem to be absolutely certain.
Food for thought indeed!

Absolutely brilliant…thank you. I like the term ‘increase earth’s coupling with space’ I have been trying to explain this to the numpties for ever.
One question I ask CO2 Warmists is, ‘have you ever noticed the outside temperature when flying on a plane at cruising altitude…-30 to -60 degrees C. right? Have you ever looked down and wondered what is happening at the top of the cloud layer…heat loss right? So if the atmosphere was to get warmer wouldn’t these clouds simply rise a little higher because of convection and lose their energy through radiation into the vast reservoir of coldness above?
Interestingly I find that when I use words like radiation and convection they tend to glaze over and lose interest. In fact I don’t think that ‘science’ matters that much to believers…
Keep up the good work guys.

I am an IR expert, 20+ years in the field.
CO2 is an IR absorber of only narrow wavelength bands of IR.
Water vapor is a much more stronger IR absorber because it absorbs very large wavelength bands of IR.
In addition, water vapor is approx 3.5% of the atmosphere or 35000 ppm. (That’s a global average. At the poles the air is drier. In the tropics, the air is much wetter.)
CO2 is only about 390 ppm.
So, water vapor from a ppm point of view is probably 100X greater in effect as a greenhouse gas from an atmospheric percentage only compared to CO2. (I rounded up slightly because the tropics have more effect than the polar regions, having more water vapor to absorb and store solar energy.)
In addition, a molecule of H2O is also quite a few multiples greater in absorption of IR compared to a molecule of CO2.
Take a look at absorption spectra for H2O: http://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC
For CO2: http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC
Just eyeballing these two NIST absorption spectra curves for H2O and CO2, it appears H2O may be at least 10X greater at absorption per molecule than CO2 is.
Thus, the comparative effects on ‘global’ warming, changes in H2O composition in the atmostphere are probably 1000X greater than CO2 changes in terms of contribution to ‘greenhouse effect’.
give or take a bit for some error =>>>>> approximately 1000 TIMES!!!!
CO2 is a non-issue compared to water in the atmosphere.

As long as we’re on the subject, most people don’t realize that the most accurate CO2 measuring devices also are IR based. They utilize those narrow bandwidths of CO2 IR absorption to measure the amount of CO2 in an atmospheric air sample.
A while ago, I took a look at the history of the supposed pristine CO2 measurements at Mauna Loa. I pulled up two papers (Keeling 1960, and Thoning 1989) describing the methods, calibration protocol followed, etc.
They have been following very good protocol. However, they have to constantly calculate out the effects of the nearby Mauna Loa volcanic activity. Mostly during night times, due to the prevailing winds, the CO2 measuring devices do jump showing dramatic increases in CO2 from the volcanoes. They supposedly developed algorithms to eliminate those errors. I haven’t looked at those yet.
HOWEVER, that activity from Mauna Loa volcanoe, has another effect that I HAVE NOT SEEN THEM TAKE INTO CONSIDERATION.
If Mauna Loa volcanoe is potent enough to send their CO2 measurements skyward, that means that WARM AIR from the volcano at night, is also affecting their temperature data. It’s the same warm air that contains increased CO2. And I would bet it also has biased their night time temperature data. BUT THERE IS NO MENTION THAT THEY HAVE FACTORED THAT WARM AIR EFFECT FROM MAUNA LOA VOLCANOE OUT OF THEIR TEMPERATURE RECORDS!
In my opinion, the temperature data from Mauna Loa station is greatly suspect from what I can see.

Domenic- the CO2 measurements by Scripps Institute are taken in several locations around the world including the locations near the North and South pole. See http://scrippsco2.ucsd.edu/research/atmospheric_co2.html These measurements support the findings of the measurements at Mauna Loa. They also show there is a lag of CO2 from the Northern to Southern Hemisphere (the levels in Antarctica lag those in the Northern hemisphere), as expected given the gains in CO2 are primarily from anthropogenic sources.
The models used by climate modelers show that the heat balance in the upper atmosphere from increased concentrations of CO2 is what matters, not its effect at sea level where water vapor dominates .
Dennis Wingo- With regard to your statement that climate modelers assume Co2 emits as a black body (emissivity of 1) I believe is not true (the emissivity of CO2 in the IR range is quite low). Further, your statement that is not possible to achieve a measurement less than the accuracy of an instrument is also not correct, as the accuracy can be increased by taking many measurements (up to a threshold). The resultant accuracy is approximately proportional to the square of the number of readings. This holds true in several fields. For example one can determine the position of a smear image of an object on a digital sensor to the resolution of 1/5 the size of a pixel (so-called super-resolution techniques). The recent findings of earth-like planets around other stars uses the change in apparent brightness of the star when a planet or plants are in different positions on their orbit. The sensitivity of the systems used in these measurements is extraordinary, well beyond what scientists thought was possible with state-of-art equipment. By the way where did you see that AGW scientists are measuring temperature to an accuracy of one thousandth of a degree (K?)?

Steve Reynolds says:
February 13, 2011 at 2:32 pm
I agree with everything MC said except (as Jim D noted) that IR is not reflected by CO2, it is absorbed and then re-emitted in all directions
=================================================
Steve, Since it’s constantly being exposed to IR, when it’s saturated, does it just reflect because it can’t absorb any more?
Or is it in a constant state of absorbing and re-emitting? neutralizing itself?
Since it’s constantly being exposed to IR, does [?? ]

What one is measuring is interesting. But one of the problems in this debate is the assumptions made by the AGW proponents and the fact that everything is treated as if it were an average. Averaging can be a useful tool. However, it is almost invariably the case that when one examines any given individual scenario, one is looking at something other than the average. In other words, the average is rarely encountered in the real world experience. This obviously has a bearing when one considers what they wish to see when making a measurement. Ken Coffman ponders upon an experiment where he is hoping to measure back radiation of 300w per sqm, but this is the so called average back radiation and this raises the question of precisely where on planet Earth would you see that amount of back radiation? It is highly unlikely to be seen at the location where he was conducting the experiment. That being the case, the results of the measuring experiment may tell one little about the effects of CO2.
I can understand that CO2 absorbs IR and then re-radiates this in all directions, some up, some sideways and some downwards etc. This scattering is a continuing process such that I can understand that as a consequence of that, CO2 delays IR finding its way out to space. However, what I do not understand is how this effectively heats up the Earth.
The average global temperature of the Earth will only heat up if the amount of energy received from the sun is not fully re-emitted back to space (by way of all forms of energy dispersion). But CO2 merely delays the escape of IR radiation, it does not provide an impenetrable shield preventing the IR from escaping back to space.
This then begs the question whether the encumbrance/delay caused by CO2 has any significant impact. The answer to this appears to me to be whether the delay is of such magnitude that all the IR does not have time to escape to space during the time when the Earth is not receiving energy from the sun. Whilst this process is happening 24 hours a day, simplistically the question is whether during the period of night there is sufficient time for all the energy received during the day to escape back into space. If there is sufficient time during night for this to happen, then there is no effective energy entrapment and the Earth will not be heating up.
IR travels at the speed of light. Approximately 300,000 km per second. If a photon of energy was to take a direct route to space this would involve a distance of about 120km. If because of the presence of CO2 in the atmosphere, the photon does not take a direct route but instead bounces around millions of times taking a zigzag course into space (bearing in mind that the density of CO2 decreases with height), we are delaying the IR escape into space by minutes. It is clear that all the energy received during the day, can (subject to water vapour and clouds etc) escape into space within less than an hour of sunset even if the concentration of CO2 were to double. So how does CO2 cause warming in the real world in which we live in?

Really nice article.
I would like to see much more discussion of the actual physics involved here because this is all happening at the quantum level – where physics is king – not in climate models where 20 km-square boxes and just 21 layers of the atmosphere is king.
The numbers is this debate are staggeringly huge as well as staggeringly small.
– the energy represented by a solar photon spends an average 43 hours in the Earth system before it is lost to space. Some spend just a millisecond while a very, very tiny percentage might get absorbed in the deep ocean and spend a thousand years on Earth or longer. In essence, the Earth has accumulated 1.9 days worth of solar energy. If the Sun did not come up tomorrow, it would take around 86 hours for at least the land temperature to fall below -200C.
– the energy represented by a solar photon spends time in 5 billion individual molecules on Earth before it escapes to space. That means it is bouncing around from molecule to molecule to molecule almost continuously. The IR emitted by the surface is not skipping Nitrogen and Oxygen molecules and preferentially seeking out CO2 and H20 only. Every molecule on Earth and in the atmosphere is participating in this process and does so continuously. Maybe CO2 or H20 provides the initial absorption, but that energy is shared amongst the rest of the atmospheric molecules almost immediately. What happens to it then?
– The surface accumulates almost none of the solar energy which hits the surface during the height of the day. 960.000 joules/m2/second is coming in and 959.083 joules/m2/second is moving up and away from the surface. At night, virtually no energy is coming in and only 0.001 joules/m2/second is flowing up and out to space. That is not consistent at all with the greenhouse theory and the back-radiation theory. It is more consistent with energy flowing from hot to cold continously (like the second law of thermodynamics) and it flows faster the more there is a differential between that hot and cold.
– We need a time perspective on radiation physics because it is happening at the speed of light and at the miniscule amount of time that a molecule absorbs that energy before passing it on through emission or collisional exchange. CO2 holds onto an absorbed IR photons for an average 0.000005 seconds before it is emitted or passed onto another molecule, Every atmospheric molecule hits another atmospheric molecule every 0.00000000015 seconds, an emitted IR photon from the surface could escape the atmosphere in just 0.000016 seconds at the speed of light – yet it actually takes 40 hours to make the journey. In the Sun, the average photon takes 200,000 years to make it out.
Is there a climate model that can simulate that accurately? It would be far too complicated for any computer even 1000 years from now to be able to simulate accurately. We have to empirically measure what is really happening in such a complicated system and base models on that instead. What is really happening is that the theory is off by at least half to date.

steven mosher says:
February 13, 2011 at 3:39 pm
“yup, but there is more to it than that. If you want to do IR design today ( of sensors, or counter measures or stealth technology) the physics you use is the same physics that many skeptics deny. good thing we don’t let them design the machines that our
safety as a nation depends upon.”
======
WOW, did you just say skeptics are too stupid to defend themselves??
Sounds like you helped protect us, thanks for that!!
I’ll say it again, thanks.
Now, it is time to protect ourselves, from ourselves.

Wonderful Stuff ……… I would like to confirm that CLOUDS ( shouting loudly ! ) are the winners in my book, I have just spent 5 days on a very remote beach on the west coast of Baja, no people, no lights, nothing ……. just the big blue watery thing called the PACIFIC, the big yellow thing called the SUN and on one cold windy day some white stuff called CLOUDS ………. they had a stunning effect for that day, then were gone.
In the isolation that I was experiencing the big three just made sense………Thanks for the very interesting IR info and discussion.

“For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.
If not, it is not science, it is guessing.
More like a horoscope…”
Completely nailed AGW to the mast….
Or he could have said “More like a religion…”
Either is probably acceptable…

John S says:
February 13, 2011 at 4:05 pm
Domenic Wrote:
“Thus, the comparative effects on ‘global’ warming, changes in H2O composition in the atmostphere are probably 1000X greater than CO2 changes in terms of contribution to ‘greenhouse effect’.”
This fact has been acknowledged by the AGW community, but as their argument goes, the relatively small added heat from CO2 creates a positive feedback loop that includes adding more water vapor into the atmosphere until there comes a ‘tipping point’ where the global temperatures go into thermal runaway.
CO2 is the “trigger” of of this positive feedback AGW, not necessarily the source of all the extra heat.
As a “warmist,” I cannot deny that CO2 does absorb and re-radiate heat energy. It is the existence of positive feedback vs. negative feedback mechanisms in the atmosphere that is at the heart of the global warming debate.

It is more the insistence that there is one linear positive feedback – the rate of water evaporation into the atmosphere and then water vapor acting solely as a ‘green house gas’ that is at the heart of the debate. For example, if the water vapor feedback is initially positive but then becomes strongly negative due to albedo effects of clouds and release of latent heat at height above the optically thick CO2/H2O layers of the atmosphere (this appears to be shown to be the case by satellite metrics) then the AGW hypothesis fails.

Good discussion that adds to the recent posts I made about experiments using an IR thermometer to get a sense of the “effective” temperature of the sky as seen from the ground.
The important thing that this experiment shows, is that unless the ground or ocean surface is receiving direct sunlight its entire view to the sky is in effect a very very cold surface. As you mention it is frequently off scale low on my IR thermometer which reads down to -76 deg F (-60 deg C) at emissivity 0.95 setting.
As a result a surface like the ground, a roof, or the ocean surface must always be losing heat to the sky by IR if it is not directly illuminated by the sun (or scattered sunlight from clouds etc.) The only other source of heat energy to maintain the temperature of that surface must come from heat transferred from the air, which by comparison is very small unless there is air motion.
It is perhaps a subtle distinction for some folks, but the CO2 and water vapor “back radiation” does not “warm the ground” or the ocean surface, it only “reduces the rate at which it is cooling by IR radiation” to the apparent surface of the very very cold sky.
As I showed in the measurements I made in the IR, due to this constant IR exchange between surfaces and the cold sky, there is very little relationship between the air temperature and nearby surfaces. At night, concrete is a very efficient radiator in the IR being like asphalt a nearly perfect black body radiator with an emissivity in the high 90% range (different sources give different values but most cluster between 0.95-0.98 for both).
What is more important, in a built up area, is a given piece of ground has a significantly reduced view of the sky due to buildings. As a result it cannot cool as rapidly through IR radiation to the sky at night because most of its hemispherical view is no longer of the open sky but rather building walls that are only a few degrees cooler than the air temperature rather than deep into the subzero IR temperatures of the open sky.
The urban heat island effect is as much to do with changes in visibility of the sky, as it is about waste heat lost from buildings. Even if you built an empty town that used no energy, ground measurements would still be warmer at night due to this change in the IR view of the sky due to structures and modifications of the topography that limit the hemisphere of the sky that is viewable from any given surface.
An analogy could be made if you replaced IR radiation with visible light. The sky would be a deep black but all nearby surfaces are very bright . The illumination of the ground surface would be completely dominated by the bright surfaces in a built up area, where in the open prairie or desert the illumination of a flat surface would be completely dominated by the black sky, with only a trace of scattered light from the nearby ground.
No matter how much you insulate buildings or reduce their energy consumptions, you will not change this IR view issue to the sky. Surfaces will always be warmer in a built up area than they would be in the open unobstructed environment of open ground regardless of energy consumption.
Larry

“bulbs emitting 300W/m2 is simply impossible, because 300W/m2 corresponds to a very low temperature!”
It wouldn’t be a conventional “bulb” first of all because those are nowhere near blackbody spectrum and second of all because they’re near infrared not far infrared.
Your “light bulb” would be a piece of black metal with an area of 1 square meter maintained at a temperature at of -23.4C. In most cases you’d have to be cooling it below ambient temperature unless you were operating it outdoors the other night in Oklahoma when it hit -35C then you’d need to run a bit of electricity through it to heat it up some.
This is essentially what the great experimental physicist John Tyndall did 150 years ago when he experimentally verified infrared opacity in various gases. Tyndall’s main “light bulb” was a copper vessel painted with lamp-black filled with boiling water which emits a blackbody spectrum in the far infrared and maintains a pretty constant temperature without much hassle since water won’t heat above its boiling point without pressurizing the vessel. It was aimed at a brass tube polished to a mirror finish on the inside and capped on each end with a plate of rock salt (rock salt is practically transparent to infrared) with valves and a vaccuum pump to evacuate the tube and introduce the gases he wanted to test. On the far end had a thermopile and galvanometer. The galvanometer response was non-linear and so to keep the thermopile outputting a voltage in the linear high-sensitivity range of the device he put another “infrared source on the backside of the thermopile with an adjustable shield to regulate how much radiation the thermopile received from the backside. The setup was quite sensitive and just a warm body in the same room with it would compromise the experiments. To demonstrate its sensitivity Tyndall would bring the thermopile/galvnometer into halls where he was giving a lecture, aim it at a wall on the other side of the lecture hall then have a member of the audience step into its view and the galvanometer would peg at the max reading. So a warm body moving around the lab during an expermental runs didn’t compromise the results he read the galvanometer from a distance with a telescope. It was quite the ingenious experimental setup given the times (1850).
The thermopile was quite sensitive and just a warm body in the same room with it threw it off so

steven mosher says:
yup, but there is more to it than that. If you want to do IR design today ( of sensors, or counter measures or stealth technology) the physics you use is the same physics that many skeptics deny. good thing we don’t let them design the machines that our
safety as a nation depends upon.
Wow, mosher. You must be bored to start taking cheap shots at strawmen. As far as I know, there aren’t many skeptics that deny the physics, just the conclusions that Earth is going to see a large temperature increase because of it.

There’s no need to be confused. The “canard” the author refers is no canard but a manifestation of his ignorance. The infrared absorption characteristics of various gases was measured experimentally 150 years by John Tyndall. If you shine far infrared light through a column of IR-transparent gas the amount of radiation you get on the far side of the column is the same as you get going through a column of vacuum. If you replace the transparent gas (like nitrogen) with an IR-absorptive gas (like water vapor) there is less radiation emitted at the far end of the column. The gas absorbs the radiation from a directional source and re-emits it in all directions. In Tyndal’s apparatus there were only two exits for the radiation since the column was a brass tube polished to a mirror finish on the inside – the two exits were plates of rock salt at either end of the tube. The radiation entering the column remains the same no matter what gas (or vacuum) is in the column but the radiation exiting the column at the far end varies according the kind of gas in the column. Energy must be conserved so what’s missing at the far end of the tube has to be going somewhere – in fact it heats the gas which increases the amount of energy the gas is emitting and since the gas emits in all directions some of the energy goes through the rock salt entrance plate instead of the exit plate while some smaller portion will heat the brass tube through conduction and some even smaller amount will heat the tube through absorption because even brass polished to a mirror finish isn’t quite 100% reflective.

Well said, we should stop focusing on CO2, as if that is all that is going on. – Anthony
===============================================
Now that really was brilliant! good one………

To Steve Reynolds
1. There is not a great deal of difference, if any, between liquid phase H2O spectral transmission and water vapor spectral transmission. I used those two graphs because data from NIST tends to be more reliable than most that I have seen.
But here’s another graph for you http://en.wikipedia.org/wiki/File:Atmosfaerisk_spredning.gif
See the wide absorption band at 5.5 to 7.7 microns…that is entirely by water vapor, H2O. Compare it to the narrow bands absorbed by CO2 in the same graph. In the vapor state, it is still at least 10X greater for this wavelength spread.
There is a problem though, and that is that we have to speculate over the entire spectral output of the dominating forces especially the sun, which outputs much energy in shorter wavelengths to the earth. To my knowledge, that data (spectral absorption and transmission and reflection of CO2 and H2O) has never really been assembled as there had never seemed to be a need for it.
2. CO2 does indeed have a reflective component as does H2O. Only a black body has no reflective component. The reflective component of H2O is better known than that of CO2 because water is more common, and has been tested for IR more thoroughly. All real world materials are reflective, absorptive and emissive. In general, metals are highly reflective (think Al foil, etc) on one end of the scale, organics and others less so, water being one of the most absorptive, least reflective. And the reflective component is highly wavelength measured dependent, as well as angularly dependent (the angle with which the wavelength strikes the molecule).
But for magnitudes of the effect on the atmosphere in terms of greenhouse effect, the known data is sufficient to see the HUGE differentials between water vapor effects vs. CO2 effects.

Domenic says:
February 13, 2011 at 1:30 pm
“In addition, water vapor is approx 3.5% of the atmosphere or 35000 ppm. (That’s a global average. At the poles the air is drier. In the tropics, the air is much wetter.)”
True enough. It varies between 1% (Sahara) and 5% (Amazon) except for Antarctic interior where it is close to 0%. But that’s at the surface. Adiabatic lapse rate squeezes out the water vapor with falling temperature while CO2 concentration remains constant with altitude.
Tyndall (circa 1850) however found that the concentration of the gas doesn’t matter but rather the total amount of the gas in the column is all that matters. He confirmed that by varying the pressure and length of the column. Tyndall performed literally thousands of experiments with varying, varying pressures, varying column lengths, and varying infrared frequencies.
To begin understanding the physics of greenhouse gases one must at least be familiar with what was experimentally demonstrated by physicists in the mid-19th century.
There’s plenty to complicate the situation in the real world beyond comprehension because the atmosphere is a dynamic system with varying gases, pressures, and many physical processes other than radiation going on that are moving heat from one place to another and radically different and rapidly variable rates.

Anthony,
This exchange was a treat, it amazes me sometimes what can be learned on the web.
This quote
“For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.
If not, it is not science, it is guessing.
More like a horoscope…”
—–
Is intriguing as well. Gore and company stopped long ago trying to prove anything. They were more interested in having enough of their theories “accepted” to stay at the grant trough. In a way it is reminiscent of the times when it was “accepted” that the Sun orbited the Earth. But then it was more for religious reasons than scientific. Today Gore strives to maintain his religious acceptance of CAGW to prop up the price of his offset credits.

A safe statement is “increasing atmospheric CO2 will result in increasing surface temperature if nothing else changed“. What causes “confusion at a higher level” is that lots of other things DO change and the amount of warming directly attributable by CO2 infrared absorption and re-emission is small and can be utterly swamped (lost in the noise) by many other dynamic processes. Water in all its phases has the starring role in shaping our climate. CO2 plays a major role in surface temperature only during so-called “snowball earth” episodes when most of the water vapor has been frozen out of the atmosphere and there’s little to no liquid water presenting on the surface. In that case there are no working CO2 sinks so volcanoes, which keep on belching out CO2, gradually build up the amount of CO2 in the column until there’s enough greenhouse effect to begin melting the planet. If it weren’t for CO2 the earth would likely be covered in ice with no hope of ever melting. That’s the most commonly accepted hypothesis at any rate and I personally haven’t seen anything that seriously disputes it.

wayne says on February 13, 2011 at 7:01 pm

Hans Erren says:
February 13, 2011 at 4:57 pm

Adding water vapour in the tropics gives the tropics a greenhouse effect, I remember very well when I left the airconditioned hotel in Dhaka Bangladesh, a wall of humid heat hit me and I had to wipe my glasses.
Every added particle to the atmosphere is a small downward radiator, adding more particles therefore adds more radiators. That’s in a nutshell the greenhouse effect.

That’s right. Every added particle to the atmosphere is a small upward radiator also, adding more particles therefore adds more radiators. That’s in a nutshell is why there is no real “greenhouse effect”. The two effects always cancel. You say ‘more warming downward’ and I say ‘also equal cooling upward’.

What you have said, Wayne, does not seem correct to me.
It seems to me that approximately half the energy absorbed by CO2 would be re-radiated upwards and half downwards.
They do not cancel.
The energy remains in the atmosphere for a little longer than it otherwise would, but I suspect that it does not matter as H2O transports much more energy out of the atmosphere and any that is “trapped” by CO2 quickly departs during the night.

Dennis Wingo says:
February 13, 2011 at 7:17 pm
… The absorption/emission of CO2 has two dependent variables, temperature and pressure, neither of which are accurately characterized in the models used by the AGW community. …
– – – – – – – –
Dennis, I see you great point but could you expand a bit on your statement above? I’m wondering if that could be temperature and density, for a slightly warmer atmosphere will expand but the mass remains constant, therefore, density drops but the pressure remains constant at sea level (average that is). Does it make sense?

To Dave Springer
Re the measurement of IR absorption.
The polished tube method is not exact. It’s an approximation. It does not account for angular effects of wavelengths and reflective effects of wavelengths striking the molecules accurately. In addition, it relies on imperfect ‘spectal window transmission coatings’ on the sensor window material, and other factors.
The science is nowhere as accurate as many believe it to be.

Brilliant conversation, thanks for sharing.
Considering the energy smart rattle being waved by local authorities, one wonders how derelict Urban Authority, IR emission equipment callibration, will be.
And i’ve learnt the hard way that the moment one puts Red on a map, some policy wonk will smell promotion and run with even the most tenuous data, and as this site so often points out Policy = Misspent funding. Usually when one says IR, the colour red shows up somewhere, and RED = Hot right and away we go.
One may point out a scale can be quite tight, with the banding representing a single degree, case in point, IR work done in winter. All of a sudden ones city glows bright red, the Policy wonk will scream ‘Look at all that energy wasted!’, until Johnny lab coat points out, ‘That sir is a mere 14 degree’s centigrade’. And you’d be amazed when you point out that water holds a lot of heat, their eyes cross, they don’t like the notion the very landscape is bleeding heat.
I’d be keen to know what tolerances and ranges equate to a fair IR reading within an urban environment, and with emissivity being so key, one can imagine Urban Authorities taxing by the W/m radiated.
Good luck with your endeavors.

steven mosher says:
February 13, 2011 at 3:39 pm
If you want to do IR design today ( of sensors, or counter measures or stealth technology) the physics you use is the same physics that many skeptics deny.
And if you had any idea what that was, you would have told us instead of delivering that empty and useless trollbuttal. What physics are being denied? Put up or shut up!

Key point by Mikael Cronholm about the uncertainties……

……it is always easier to calculate what an object emits than what it absorbs, because emission will be spreading diffusely from an object, so exactly where it ends up is difficult to predict.

Mix in variable convection and possible gas density ‘layering’ and the difficulty in measurement is compounded.

richard verney says:
February 13, 2011 at 4:11 pm
“CO2 delays IR finding its way out to space. However, what I do not understand is how this effectively heats up the Earth.”
It doesn’t heat the earth any more than insulation in your attic heats your house in the winter. It slows down how fast heat can escape. Since the heat is arriving at the same but leaving at a slower rate this causes the surface to become warmer which then increases the rate at which heat moves across the boundary. A new higher surface equlibrium temperature is thus established. In reality too many other things change too rapidly for equilibrium to ever be attained but the theoretical equilibrium point will rise and thus the target which the system seeks is that much higher.

Mikael Cronholm,
In your paper you say “Radiation is the strongest heat transfer mode”. Please elaborate. From my anecdotal experience conduction and evaporation are stronger modes of heat transfer: sweating is better for cooling down than not, blowing on a cup of hot chocolate is better than letting it cool by radiation.
What do you think of the concept of “back radiation” whereby “downwelling radiation” from colder air warms the warmer surface of the earth.

Mikael Cronholm says February 13, 2011 at 8:02 pm

Water is an amazing substance …

All your Joule are belong to us.

Mikael Cronholm says:
February 13, 2011 at 8:02 pm
“There are no scientific proof, one way or the other.”
Insofar as some gases absorb infrared radiation and some do not was scientifically proven in the mid-19th century. Your continued denial only means you know less about the physical properties of gases than mid-19th century physicists.

Bill Illis says:
February 13, 2011 at 4:55 pm
In essence, the Earth has accumulated 1.9 days worth of solar energy. If the Sun did not come up tomorrow, it would take around 86 hours for at least the land temperature to fall below -200C.
What!?? Where I live it can sometimes fall from +40C to +36C between sunset and sunrise. I think maybe you left the atmosphere out of that equation.

MC – excellent discussion, simple straight forward answers referencing the actual physics. We need more of this in the discussion, not more slogans, so thanks for stepping up!
Now – H2O vs CO2
For all the skeptics who have been trying to present the argument that water vapour is so much stronger an absorber than CO2 that CO2 doesn’t matter, sorry, but you are wrong. And I am a hard core skeptic!
Water vapour is in fact a much stronger absorber than CO2 and in the same approximate spectrum. If water vapour and CO2 were mixed evenly in the atmosphere, that would make CO2 insignificant. But they are NOT. CO2 is reasonably well mixed throughout the troposphere, but water vapour concentration falls rapidly with temperature. As a consequence water vapour declines with both altitude and latitude. What ever CO2 does or does not do, well over 90% of it exists in the atmosphere at temperatures low enough that water vapour is also low enough that CO2 becomes significant by comparison.
That said, I repeatedly ask the logical next question that I have yet to see a reasonable answer for from the warmists. If CO2 reflects/re-radiates/back-scatters what ever you want to call it, upwardly bound long wave, it makes sense that this would result in a temperature increase which in turn would increase water vapour. BUT, and I repeat BUT, does it not also follow that any increase in water vapour works both ways? That is, certainly the water vapour would re-radiate upward bound LW from earth surface, but it would ALSO re-radiate DOWNWARD bound LW too. The downward bound LW that would normaly have been absorbed at earth surface now has an increased % chance of being re-radiate back up. And we’re not talking about just the downward LW from increased CO2, we’re talking ALL the downward LW from ALL sources. In other words, increased water vapour may in fact have a net positive feedback, but it has a huge, built in, negative feedback too that likely renders the whole calculation near meaningless.
THERMAL QUENCHING – I saw some comments on this too. This was a big issue for Ernst Beck (may he rest in peace) who felt that this was an under estimated effect of CO2 LW absorption. His explanation was way, Way, WAY over my head. It was a seriously complex issue as there are so many factors that govern how an individual molecule can or cannot aborb or lose a photon when in collision with another dismilar molecule, at what temperature, and at what time period before re-emission would happen anyway. I don’t have any certainty that he was correct, but the explanations and rebuttals showed one thing pretty clearly – no one has a real good grip on the complexities, in the atmosphere in particular, and measuring thermal quenching is darn near impossible.

Richard Sharpe says:
February 13, 2011 at 7:33 pm
What you have said, Wayne, does not seem correct to me.
It seems to me that approximately half the energy absorbed by CO2 would be re-radiated upwards and half downwards.
——-
Two units of energy goes up, cooling the suface, surface -2, and is absorbed warming the atmosphere, atmosphere +2, your radiators means one unit always goes upward to space, atmosphere now +1, space +1, and one back down to the surface, surface -1, atmosphere is now zero. Plaease tell me what has just happened, for the surface is -1 unit of energy and space is now +1. Why is this so confusing to you?
And I do know this is ignoring energy that goes via the radiative window directly to space but that effect is exactly the same.

u.k.(us) says:
February 13, 2011 at 8:17 pm
Slacko, — other than your rant, have you anything to add?
I can’t wait.
What rant? I repelled a rant and posed a question.
So while you’re waiting, maybe you can figure out “What physics do skeptics deny?” If you lot think you can get away with accusing me of your own folly, you’re wasting your time.

From the article:
“KLC: I still feel like I’m missing something. IR heat lamps are pretty efficient, maybe 90%? Let’s pick a distance of 1 meter and I want to create a one-square meter flooded with an additional 300W/m2. It must be additional irradiation, doesn’t it? That’s going to take a good bunch of lamps and I would feel this heat. However, I go outside and hold out my hand. It’s cold. There’s no equivalent of 300W/m2 heater in addition to whatever has heated the ambient air.”
What’s missing is that the lamps are already radiating based on their room temperature. The 300W/m2 from the lamps when they are turned on is, of course, additional, whereas the 300W/m2 from the sky is the total heat flux from the sky. The two are not comparing the same thing at all.
It was also nice to see all the talk about the importance of emissivity. It’s a subtle point that many get wrong.

@chico sajovic, 8.20. I think you talk about the furnace paper then, and in a furnace radiation is much stronger than any other mode. In the radiation section at the bottom, where the flames are, radiation is completely dominant. Up in the convection section, the tubes draw out the remaining energy they can from the exhaust gases, but that is much less than what is added to the feedstock in the radiation section. The clue is that radiation increases with the temperature to the power of 4, according to Stefan-Boltzman’s law, while conduction and convection don’t. Conduction is linear, convection probably less strong than linear, with temperature (logic: just because a surface is 1000C it does not create a storm around it by convection).

@ Dave Springer. I was not discussing properties of gases. I just say there are no scientific proof that increased CO2 emission causes climate change, or that it does not. And I am not on any side in the debate, for that very reason.

I realize that many of you are not fond of the website realclimate.org. However, there are useful posts on the above subject (CO2 radiation exchange in upper atmosphere) at
http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/
and more importantly at
http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument-part-ii/
Also an important data source for the absorptivity of CO2 is given in the data found in HITRAB at http://www.cfa.harvard.edu/hitran//
This software uses data from HITEMP https://kb.osu.edu/dspace/handle/1811/13476
“The HITRAN database has been recognized for more than 20 years as the international standard compilation of spectroscopic absorption parameters for atmospheric gases.”
The following paper has some of the CO2 data (available on line):
http://faculty.uml.edu/robert_gamache/papers/Rothman_et_al_Preprint.pdf
From what I have read the emissivity of CO2 does vary as a function of both pressure and wavelength. But I am not an expert on this subject.

Jim D says:
February 13, 2011 at 5:48 pm
The measured IR from the sky is pretty much all emitted by CO2 and H2O molecules …
No Jim. If that were true then the warmth of the sun on my face would be coming in from all directions equally. But even a blind man …
Or do you mean at night?
And do you really mean to tell us that nitrogen can’t radiate IR?

Ian W says:
February 13, 2011 at 12:35 pm
When water vapor in the atmosphere condenses into liquid water and then changes state again and becomes ice, it gives off latent heat for both state changes.
Does that latent heat release follow Stefan-Boltzmann’s radiative equation ?
No Ian, latent heat is not really related to S-B. Latent heat means that when you add or remove heat, energy, from a substance it will usually change its temperature, except when there is a phase change. At a phase change, for example melting or evaporation, you will be able to add or remove heat without a change in temperature taking place, the change of heat in the substance causes the phase change to take place instead. In the case of freezing water for example, there is molecular kinetic energy stored in translational movement, i.e. the molecules move around relative to each other (they have a mass, they move=energy). When the liquid turns to a solid crystalline structure, that energy of movement must be removed before the molecules can stand still in relation to each other. That is the latent heat that is released from the water when it freezes. Fruit orchard are actually sprinkled with water to prevent the plants from getting damaged on cold clear night in the spring. The water freezes and give off heat to the plant, preventing it from getting too cold.
So, as far as S-B is concerned, this process will only influence the input T in that equation, insofar as the cooling or heating of the substance reaches a plateau when latent heat takes effect. The radiation will still always depend on the temperature and emissivity of the substance.

hotrod ( Larry L ) says:
February 13, 2011 at 5:49 pm
It is perhaps a subtle distinction for some folks, but the CO2 and water vapor “back radiation” does not “warm the ground”
Why not? Does it have to do with the 10 micron wavelength?
or the ocean surface,
Why not? Those photons have to go somewhere. Why does this look like a “missing heat” problem?
it only “reduces the rate at which it is cooling by IR radiation” to the apparent surface of the very very cold sky.
So “back radiation … only reduces … cooling.”
Huh??

chico sajovic says:
February 13, 2011 at 7:45 pm
“Back Radiation” is such a horrible analogy, description or way to think about heat transfer in the atmosphere, that I wish it would just go away. What we are concerned with is the flow of heat from the surface of the earth to space. Its not that the surface warms the co2 in the air then the co2 “back radiates” re-warming the surface, its that when the co2 in the air is warmed the flow of heat from the surface to the warmed co2 is reduced, thus increasing the temperature of the surface until the flow of heat returns to equilibrium.
——————————————-
I don’t quite get the preoccupation with “the surface” when it’s actually the air temperature that we measure, not the ground.
GHG’s don’t make the ground warmer in the daytime than insolation is able to do and at night, the paltry amount of energy accumulated in the surface doesn’t provide much residual warmth to the air, especially since it’s only a fraction of outgoing LWR that is absorbed.
The heat capacity of the air is not enormous but radiative heat loss is not really rapid at these temperatures, either.
Something like that?

Slacko 10.33, perhaps I can explain. If you look at the beginning of Ken’s and my conversation I mention something we call “apparent temperature”. It is the blackbody equivalent temperature that something radiates. We use it to determine the reflected radiation in commercial IR measurements. That is also what would be measured in that IR image at the top if the camera was able to measure that low (and emissivity was set to 1 and distance to zero).
So consider the exchange of heat between earth and the sky. It depends on the balance between incoming and outgoing radiation, the net difference is the gain or loss. If you have a very clear sky, the sky will have a low apparent temperature, so the temperature difference between the earth and the sky is the greatest. (You will still have a big influence from the atmosphere, otherwise the apparent temperature of the sky would approach absolute zero. -273C.)
Clouds will have a higher apparent temperature, meaning that they will radiate more towards the earth than a clear sky would do, so the difference is smaller and hence the heat loss is also smaller, than with a clear sky.
So, yes, it is true that radiation from the clouds will prevent cooling of the earth, allowing the earth to keep its heat to a larger degree. But as the clouds will not be hotter than the earth, they will not reverse the heat flow from the earth to become a gain rather than a loss, they can just make it less of a loss. The sun will give the positive contribution.

Mikael Cronholm says:
February 13, 2011 at 11:12 pm
heat leaves earth by convection. Clouds prevent convection. They don’t radiate energy

richard verney says:
February 13, 2011 at 4:11 pm
I believe this is a valid question. The response –
Dave Springer says:
February 13, 2011 at 8:14 pm
fails to address the question in ignoring the diurnal cycle of solar energy input for a given location on the Earth’s surface. For CO2 to cause CUMULATIVE warming, the near surface temperature just before dawn for a single point on the Earth’s surface would have to be greater for a local air mass with greater CO2 concentration than for one with less. A simple empirical experiment could clarify this. I would be interested if anyone could point me to the results of such an experiment.

John S says:
February 13, 2011 at 4:05 pm

the relatively small added heat from CO2 creates a positive feedback loop that includes adding more water vapor into the atmosphere until there comes a ‘tipping point’ where the global temperatures go into thermal runaway.

How can it be explained that ANY increase in temperature does not cause this “thermal runaway” ‘tipping point’? If the temperature as recently as the MWP was higher than today, which it certainly was in at least some areas and possibly all, why was this mythical tipping point not reached? As it was not, what makes you believe it will be during the present warm period? Is there any evidence for this? Models are NOT evidence, BTW, as they ONLY produce what they are programmed to produce.

Slacko says:
February 13, 2011 at 10:33 pm
hotrod ( Larry L ) says:
February 13, 2011 at 5:49 pm
QUESTION
It is perhaps a subtle distinction for some folks, but the CO2 and water vapor “back radiation” does not “warm the ground”
Why not? Does it have to do with the 10 micron wavelength?
ANSWER: Because the downward re-reradiated LW is MUCH more likely be be absorbed by water vapour or other absorbers and be re-radiated back up than it is to ever hit the ground. Double CO2 instantly, wait for a new equilibrium to be established, and you have the EXACT same amount of SW going in, and the EXACT same amount of LW coming out. The EFFECTIVE black body temperature of the earth is what the IPCC claims is going to rise by 1 degree, and this is at a point high up in the atmosphere (about 14,000 feet if I recall) not at earth surface.
QUESTION
or the ocean surface,
Why not? Those photons have to go somewhere. Why does this look like a “missing heat” problem?>>
QUESTION
LW radiatiance cannot penetrate more than a micron or so of water before being absorbed. The result being that any longwave that does strike water is absorbed in a layer so thin that it immediately evaporates taking the extra energy from the LW, plus any energy that was already in that water with it into the atmosphere. Any temperature changes in the ocean have to be attributed as a consequence to other factors such as fluctuationm of SW from the Sun, rainfall, runoff and so on. As for “missing heat” that’s a measurement problem.
QUESTION
it only “reduces the rate at which it is cooling by IR radiation” to the apparent surface of the very very cold sky.
So “back radiation … only reduces … cooling.”
Huh??
ANSWER – that is an imperfect way of thinking about it, but at day’s end it is a fair description. A given photon might, in theory, be radiated upward and go straight out to space. Or it might hit one CO2 molecules be absorbed, and then re-radiated in a random direction. Up, sideways, down, what ever. For rough figuring, call it 2/3 up or sideways and 1/3 down. So no matter how much CO2 you have, the end results is always more ups than downs, and the photon eventually escapes to space, but not have hundred, to millions of absorptions and re-radiations. So adding CO2 does not add a single additional photon, not one, to the equation. All it does is increases the average number of zig zags through the atmosphere before eventually escapting to space. So yes, extra CO2 would add no extra heat at all, it would just increase the amount of time it takes any given photon to escape, and “slow down the escape” could roughly be equated to “slow down the cooling”.

P Wilson says:
February 13, 2011 at 11:23 pm
Mikael Cronholm says:
February 13, 2011 at 11:12 pm
heat leaves earth by convection. Clouds prevent convection. They don’t radiate energy
Reply: Sorry Mr Wilson, but I do not agree with what you say. (To other readers: I was not the one who made the statement above.)
Convection takes place in substances in the form of fluids and the atmosphere itself is a fluid, so convection can take place in it, including within the clouds themselves (they don’t “prevent” convection, they take part in it). It is true that heat transfers from the ground to the atmosphere, but it is still part of the heat that surrounds the planet. So assuming that we count the atmosphere as a part of our planet, as opposed to space around it, no heat will enter space by convection because there is no fluid that can circulate into space. Clouds do radiate, because everything with a temperature does.
Let us make this clear. The only way that Earth, and its atmosphere, can exchange heat with space is by radiation.

@Chemman Feb 13, 2011 at 12:57 pm:

…Since molecules are 3-dimensional and constantly in motion “green house gases” will re-radiate IR energy in 3 dimensions not just back at the earth like a reflector.

I’ve always assumed they all deal with it as 3D re-radiation – including only the downward re-radiation in the heat flow system. Otherwise some of the skeptics would have certainly ripped into them about it.

I have some hands on industrial R&D experience with heat flow vs temperature, and also with the reality of emissivity.
I ran experiments using what are called “engineering plastics” in order to find the best plastic for a 420°F application. In one, we heated the plastic to temperature and then subjected it to weight loading to see what kind of strain we got. In the process, I handled up to 500°F pieces of plastic (a bit higher than the real application, for “cushion”). I did this barehanded. Even with a thermocouple telling me the plastic was 500°F, the plastic was almost not even warm in my hand. It is not the temperature that burns; it is the heat flow. See the next paragraph…
As to emissivity, we also had highly polished and chrome plated tool steel (H13) that was oil-heated to the 420°F temperature. The polishing and chrome plating made the emissivity extremely low (how I still don’t “get”). I could put my skin well within 1/16″ of the surface of the hot metal and not even feel warmth. (It is not easy to do without jittering, but I did manage to do it, bracing my hand on something cooler, just to see.) However, once the heat transfer method went from radiation to conduction – when I actually touched the metal – it was instant BURN!
Low emissivity is amazing.
Low heat flow is also amazing.
(Note: By far the best fix for the occasional burns was using freon from a spray can. I was SERIOUSLY [snip . . irritated?] when they banned CFCs to protect the ozone hole. And I completely believe that in time that theory will be completely refuted.)

“Domenic- the CO2 measurements by Scripps Institute are taken in several locations around the world including the locations near the North and South pole. See http://scrippsco2.ucsd.edu/research/atmospheric_co2.html These measurements support the findings of the measurements at Mauna Loa. They also show there is a lag of CO2 from the Northern to Southern Hemisphere (the levels in Antarctica lag those in the Northern hemisphere), as expected given the gains in CO2 are primarily from anthropogenic sources” … W. Falicoff
“For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.” … Mikael Cronholm
So all you have to do now W.F. is show your repeatable science and you will have done something that would change the entire scientology of AGW

Very interesting post & posts! Great source of knowledge down to little known details (such as spraying water on fruit). Lot of food for thought!
I only have one question to add to this conversation: Is it at all possible to measure the energy balance (or radiation balance) of the earth. By energy (radiation) balance I mean the difference between energy input and output. Please excuse if this question is put forward in terms which fall short of physicists standarts – that´s because I am just a curious layman.

We have a little blue planet that is stirred internally by a big yellow monster, this same monster bombards us with the full spectrum of radiation. Mitigating factors protect us from this monster or we would perish. Like wise if it failed to arise tomorrow we would perish very quickly. Our little blue planet works its fanny off trying to balance an out of balance heat input caused by all sorts of wobbles and perturbations. The occasional large volcanic eruption is compensated for and the world returns to normal. A flea on elephant comes to mind as to effect of CO2 on the planetary climate. The cyclic changes we see if we live long enough are the result of the rules of thermodynamics in an open heat pump trying its utmost to balance itself.
It would be pure folly and ego on our part to contemplate that we could change the climate. Looking backward to Newton and celestial mechanics using real geometry is the key to finding the reasons behind ice ages and interglacials. When these are understood then we can look at the minor perturbations with some understanding and a modicum of confidence. Some scientists are looking at this aspect and finding a surprising correlation to the suns recalcitrant attitude.

ThomasU says:
February 14, 2011 at 3:50 am
This is indeed a big problem. Temperature measurements are used, which are inadequate, sparse and unreliable.
Atmospheric energy should be measured in joules per cubic metre. Not in temperature

“infrared radiation is what warms the earth during the day”
Infrared is the heat you feel, but cannot see.

Steve Reynolds says:, “I agree with everything MC said except… that IR is not reflected by CO2, it is absorbed and then re-emitted in all directions”
To which Latitude asks,
“Steve, Since it’s constantly being exposed to IR, when it’s saturated, does it just reflect because it can’t absorb any more?
Or is it in a constant state of absorbing and re-emitting? neutralizing itself?”.
The gases in our atmosphere (N2,O2 and CO2) do not ‘reflect ‘ light. If they did it would be impossible for us to see coherent images because the light would be bouncing all over the place. We can only form clear images where light travels in straight lines.
The same is true in the infra-red.You no doubt have seen pictures from infra-red imaging cameras, e.g. police helicopters. These are only viable because atmospheric gases do not ‘reflect’ infra-red radiation but allow it to travel in straight lines.
However, CO2 does absorb infra-red within a narrow wavelength band. The important absorption occurs at wavelengths between 14 and 16 microns (other CO2 absorption bands are not significant In the context of greenhouse warming because they do not obstruct the radiation emitted from the Earth’s surface). Photons of infra-red radiation around 15 micron have just exactly the right amount of energy to raise a CO2 molecule from one vibrational state to another one. Being thus ‘tuned’, they may be captured by a CO2 molecule which then changes state. Almost instantaneously, within nanoseconds, the CO2 molecule re-emits the photon and reverts to its original state. Because the photon can be re-emitted in any direction (spherically random) about half of them will be re-directed back to Earth and will represent an additional heat flux if they ever get there.
If the ‘excited’ CO2 molecule collides with another molecule, say of Nitrogen. before it can re-emit its captured photon, then it becomes ‘thermalised’ (or as Mark Wagner says, ‘quenched’). Its extra energy is transformed into heat and it can no longer emit a photon. If this happens the atmosphere is warmed.

Bomber_the_Cat says:
February 14, 2011 at 4:18 am
what you haven’t mentioned is the temperatures at which this 14.77 peak of c02 absorbs radiation. It corresponds to -28C which is up in the lower troposphere. When it leaves that temperature range it thermalises. Now: There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C. That is tantamount to saying that putting cold water in the freezer will cause it to be lukewarm

Jim Masterson The cloud cover is supposedly 62%. KT 1997 combines three cloud layers (49%, 6%, & 20%) to get that figure. They call it “random overlap,” whatever that means. It looks like an application of the Inclusion-Exclusion principle. I get 61.6% which rounds to 62%. Their famous energy diagram (fig. 7 in KT 1997 and fig. 1 in TFK 2009) should state: “62% cloud cover assumed.”
The Inclusion-Exclusion Principle requires that we know the overlap(s) to begin with, so it can’t give us the answer. The average of the minimum and maximum overlaps gives exactly 62%:
((49 + 6 + 20) + 49) / 2 = 62
but I’m not sure that this is what we’d get with random overlap, even if, as my calculation assumes, there are no real-world constraints.

P. Wilson says, “What you haven’t mentioned is the temperatures at which this 14.77 peak of C02 absorbs radiation”.
The CO2 absorption of photons at 15 micron is not dependent on temperature. A molecule of CO2 will absorb any photon with the ‘correct’ quanta of energy which impacts it, irrespective of temperature.
More interestingly, “There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C”.
I assume that subzero here means below zero on the Celsius or Fahrenheit scales. Now ALL objects above absolute zero emit radiation; that includes you, me and an ice cube. The amount an object emits (Stephan’s Law) and the wavelengths of the radiation emitted (Plank’s Law) is determined by their temperature. So even cold objects, such as an ice cube, emit radiation. If that radiation impacts a warmer object then it is absorbed by the warmer object. The warmer object therefore receives energy that it wouldn’t receive if the cold object was not there – and so the warm object is kept warmer than it otherwise would be. Radiation is not somehow preferentially attracted only to colder objects. Thus the presence of cold objects can keep warm objects warmer!!! This does not infringe the 2nd law of thermodynamics, only a schoolboy misunderstanding of it.
As for making the Earth warmer, remember that the Earth is warmed by the Sun. The CO2 ‘blanket’ , by sending radiation back to the surface, simply acts as insulation. The incoming solar energy is what causes the Earth’s surface to rise.
At the top of the atmosphere of course, the amount of radiation leaving the Earth will always balance the radiation coming in – no matter how much CO2 there is in the atmosphere. But we don’t live at the top of the atmosphere, we live on the surface – and it is the surface temperature which is effected by the greenhouse gases.
P. Wilson says, “What you haven’t mentioned is the temperatures at which this 14.77 peak of C02 absorbs radiation”.
The CO2 absorption of photons at 15 micron is not dependent on temperature. It will absorb any photon with the ‘correct’ quanta of energy which impacts it, irrespective of temperature.
More interestingly, “There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C”.
I assume that subzero here means below zero on the Celsius or Fahrenheit scales. Now ALL objects above absolute zero emit radiation; that includes you, me and an ice cube. The amount an object emits (Stephan’s Law) and the wavelengths of the radiation emitted (Plank’s Law) is determined by their temperature. So even cold objects, such as an ice cube, emit radiation. If that radiation impacts a warmer object then it is absorbed by the warmer object. The warmer object therefore receives energy that it wouldn’t receive if the cold object was not there – and so the warm object is kept warmer than it otherwise would be. Radiation is not somehow preferentially attracted only to colder objects. Thus the presence of cold objects can keep warm objects warmer!!! This does not infringe the 2nd law of thermodynamics, only a schoolboy misunderstanding of it.
As for making the Earth warmer, remember that the Earth is warmed by the Sun. The CO2 ‘blanket’ , by sending radiation back to the surface, simply acts as insulation. The incoming solar energy is what causes the Earth’s surface to rise.
At the top of the atmosphere of course, the amount of radiation leaving the Earth will always balance the radiation coming in – no matter how much CO2 there is in the atmosphere. But we don’t live at the top of the atmosphere, we live on the surface – and it is the surface temperature which is effected by the greenhouse gases.
P. Wilson says, “What you haven’t mentioned is the temperatures at which this 14.77 peak of C02 absorbs radiation”.
The CO2 absorption of photons at 15 micron is not dependent on temperature. It will absorb any photon with the ‘correct’ quanta of energy which impacts it, irrespective of temperature.
More interestingly, “There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C”.
I assume that subzero here means below zero on the Celsius or Fahrenheit scales. Now ALL objects above absolute zero emit radiation; that includes you, me and an ice cube. The amount an object emits (Stephan’s Law) and the wavelengths of the radiation emitted (Plank’s Law) is determined by their temperature. So even cold objects, such as an ice cube, emit radiation. If that radiation impacts a warmer object then it is absorbed by the warmer object. The warmer object therefore receives energy that it wouldn’t receive if the cold object was not there – and so the warm object is kept warmer than it otherwise would be. Radiation is not somehow preferentially attracted only to colder objects. Thus the presence of cold objects can keep warm objects warmer!!! This does not infringe the 2nd law of thermodynamics, only a schoolboy misunderstanding of it.
As for making the Earth warmer, remember that the Earth is warmed by the Sun. The CO2 ‘blanket’ , by sending radiation back to the surface, simply acts as insulation. The incoming solar energy is what causes the Earth’s surface to rise.
At the top of the atmosphere of course, the amount of radiation leaving the Earth will always balance the radiation coming in – no matter how much CO2 there is in the atmosphere. But we don’t live at the top of the atmosphere, we live on the surface – and it is the surface temperature which is effected by the greenhouse gases.
P. Wilson says, “What you haven’t mentioned is the temperatures at which this 14.77 peak of C02 absorbs radiation”.
The CO2 absorption of photons at 15 micron is not dependent on temperature. It will absorb any photon with the ‘correct’ quanta of energy which impacts it, irrespective of temperature.
More interestingly, “There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C”.
I assume that subzero here means below zero on the Celsius or Fahrenheit scales. Now ALL objects above absolute zero emit radiation; that includes you, me and an ice cube. The amount an object emits (Stephan’s Law) and the wavelengths of the radiation emitted (Plank’s Law) is determined by their temperature. So even cold objects, such as an ice cube, emit radiation. If that radiation impacts a warmer object then it is absorbed by the warmer object. The warmer object therefore receives energy that it wouldn’t receive if the cold object was not there – and so the warm object is kept warmer than it otherwise would be. Radiation is not somehow preferentially attracted only to colder objects. Thus the presence of cold objects can keep warm objects warmer!!! This does not infringe the 2nd law of thermodynamics, only a schoolboy misunderstanding of it.
As for making the Earth warmer, remember that the Earth is warmed by the Sun. The CO2 ‘blanket’ , by sending radiation back to the surface, simply acts as insulation. The incoming solar energy is what causes the Earth’s surface to rise.
At the top of the atmosphere of course, the amount of radiation leaving the Earth will always balance the radiation coming in – no matter how much CO2 there is in the atmosphere. But we don’t live at the top of the atmosphere, we live on the surface – and it is the surface temperature which is effected by the greenhouse gases.
P. Wilson says, “What you haven’t mentioned is the temperatures at which this 14.77 peak of C02 absorbs radiation”.
The CO2 absorption of photons at 15 micron is not dependent on temperature. It will absorb any photon with the ‘correct’ quanta of energy which impacts it, irrespective of temperature.
More interestingly, “There is no physical mechanism that can cause subzero temperature ranges to penetrate back to earth and warm it up beyond the nominal 14-15C”.
I assume that subzero here means below zero on the Celsius or Fahrenheit scales. Now ALL objects above absolute zero emit radiation; that includes you, me and an ice cube. The amount an object emits (Stephan’s Law) and the wavelengths of the radiation emitted (Plank’s Law) is determined by their temperature. So even cold objects, such as an ice cube, emit radiation. If that radiation impacts a warmer object then it is absorbed by the warmer object. The warmer object therefore receives energy that it wouldn’t receive if the cold object was not there – and so the warm object is kept warmer than it otherwise would be. Radiation is not somehow preferentially attracted only to colder objects. Thus the presence of cold objects can keep warm objects warmer!!! This does not infringe the 2nd law of thermodynamics, only a schoolboy misunderstanding of it.
As for making the Earth warmer, remember that the Earth is warmed by the Sun. The CO2 ‘blanket’ , by sending radiation back to the surface, simply acts as insulation. The incoming solar energy is what causes the Earth’s surface to rise.
At the top of the atmosphere of course, the amount of radiation leaving the Earth will always balance the radiation coming in – no matter how much CO2 there is in the atmosphere. But we don’t live at the top of the atmosphere, we live on the surface – and it is the surface temperature which is effected by the greenhouse gases.

W. Falicoff says:
February 13, 2011 at 3:40 pm
“… Further, your statement that is not possible to achieve a measurement less than the accuracy of an instrument is also not correct, as the accuracy can be increased by taking many measurements (up to a threshold). The resultant accuracy is approximately proportional to the square of the number of readings. This holds true in several fields. …”
Actually, repeated measurements cannot improve accuracy, it can only improve precision. If there is bias in the gauge then repeated measures will keep giving you the biased answer. Precision (e.g. the standard deviation) of the average value of the measurement can improve by the inverse square root of the sample size.
But there’s far more to it than increasing sample size. Check out MSA (Method System Analysis) or Gauge R&R (Repeatability and Reproducibility). In a manufacturing environment a Gauge (or measurement system) is not considered capable until the precision is at least 1/10th the specification range. So in terms of AGW, if the world is going to melt down at an additional 2C then the gauge should be able to repeatably and reproducibly measure to +/- 0.2C on the individuals….not multiple measurements to construct an average.

P Wilson says:
February 14, 2011 at 4:32 am
“what you haven’t mentioned is the temperatures at which this 14.77 peak of c02 absorbs radiation”
The temperature of the gas has little to do with IR absorption. The earth emits LWIR in a continuous blackbody spectrum with a peak emission at around 10um which corresponds to a blackbody at approximately 52F which is the average surface temperature of the ocean. CO2 absorbs narrow bands out of that continuous spectrum which excites the CO2 molecule and because the molecule is part of a cold dense mix of gases the excited molecule almost instantly bumps into a neighbor (most likely N2) which then thermalizes the N2. Re-emission up the upwelling narrow band energy is a continuous blackbody spectrum corresponding to the temperature of the gas at whatever altitude the re-emission occurs. The process starts from the ground up and proceeds to saturation. Looking down at the atmosphere from above with a spectrometer one sees a continuous blackbody spectrum with narrow absorption bands where the energy level falls off. The energy missing from those narrow bands is redistributed across the rest of the spectrum. The altitude/temperature to which you refer is the energy level at the top of the 15um band.
See figure 8.2 (spectrograph from 20km looking down on the north pole):
http://www.sundogpublishing.com/AtmosRadFigs.html
The blackbody emission curve is at about 265K which corresponds to the surface temperature at the pole at the time. You’ll notice a big hole in the spectrograph centered on 15um with the bottom of the hole following the 225K blackbody curve. The missing energy at 15um is what CO2 has absorbed beginning from the ground up and has been completely thermalized by an altitude where the air temperature is 225K which, applying the dry adiabatic lapse rate of 10K per 1000 meters is about 3000 meters or 10,000 feet (middle region of the troposphere).
The missing energy in the 15um, when thermalized, is re-emitted as continuous blackbody spectrum so the top of the curve at 265K (which is the surface temperature) is a bit higher than it would be otherwise. That bit higher surface temperature is the effect of CO2’s action as a greenhouse gas. It impedes the flow of 15um energy from surface to space which in effect acts like insulation making the surface temperature a little higher than it would be otherwise. The temperature of the cosmic void is about 3K and doesn’t change. The increased differential between surface and space raises the rate at which energy flows from surface to space re-establishing a new surface temperature equilibrium point between energy-in (short wave energy from the sun) and energy-out (long wave energy from the earth).
This is all undisputed except by cranks and and other assorted ignoramuses who refuse to accept the radiative absorption and emission characteristics of various gases according to physics theories that have been around for over 200 years and which were experimentally confirmed 150 years ago by John Tyndall and which have remained as well established as any theory in physics since then.
The controversy isn’t about the direct effect of increased CO2. That’s cut and dried number crunching of basic physics formulas. The bone of contention is in the feedbacks. The climate boffins on the “hockey team” insist there is a large positive feedback which will somehow cause a runaway greenhouse despite the fact that all paleo-climate evidence of every kind shows the earth has never in its history experienced a runaway greenhouse despite atmospheric CO2 levels far higher than could be obtained by burning every last drop, wisp, and crumb of recoverable fossil fuels. ALL the evidence says the feedback is negative which limits the maximum global surface temperature and where the temperature increase (we’re in a very COLD period of the earth’s history) is concentrated in the higher latitudes i.e. the tropics won’t get much warmer but the temperate and polar regions will. The usual state of affairs for the earth over the past billion years is warm and friendly for living things from pole to pole. The current terrestrial biosphere is a shrunken frozen shadow of itself much of the time over much of its extent compared to the warm (non-ice age) periods which is to say 90% of the time for uninterrupted periods lasting as long as hundreds of millions of years. The earth has been in a ice-age for the past 3 million years and ice ages are not the normal state of affairs – they are the exception to the rule of a planet lush, warm, and green from pole to pole with far higher atmospheric CO2 content and a far larger/faster carbon cycle driven by living things.

Hello Izen
Quote “There is no way that the water surface acts like a one-way street for all incident radient energy. It is not Maxwell’s demon!”
But CO2 is a demonic gas, with its wavenumber of 666.666 (15 µm)!
Is it not Maxwell’s demons casting back all the IR radiation?
The blackbody temperature to emit a peak IR of 15 µm is according to Wiens law 193.18456 Kelvin.
This equates to -79.97 Centigrade (Please do not miss the MINUS sign, yes nearly minus 80C!)
How hot can this 15 µm -80 Centigrade IR heat anything?
NoIdea

Dave Springer says:
February 14, 2011 at 7:01 am
only the problem with this theory is that the radiation goes in all directions equally, which does not change the amount of heat in the atmosphere.

Bomber_the_Cat says:
February 14, 2011 at 5:59 am
Nice. It’s heartening to see some commenters who understand the physics. “School-boy” misunderstanding might be a bit harsh but I understand where you’re coming from. A good understanding of the four years of science taught in grades 9-12 covers almost everything you need to know about this subject in biology, chemistry, and physics from how the greenhouse gases work to what acid rain from sulfate emissions does to how these thing effect the biosphere. When PhDs get involved in the conversation they start such a pedantic bickering over small details in their fields of expertise that the big picture gets lost and laypersons then proverbially can’t see the forest because there are too many trees blocking the view.

P Wilson says:
February 14, 2011 at 7:30 am
” As you know, as 14.77 microns the saturation window closes. 14.77 microns does broadly correspond to -28C. 10 microns corresponds to around 15C, the average global temperature. So the last place that c02 absorbs radiation is at the surface, which on average is above subzero. C02 is invisible to these temperatures.”
This is laughably wrong! PEAK emission frequency corresponds to those temperatures. A blackbody emits a CONTINUOUS spectrum with broad shoulders that fall off slowly on either side of the peak frequency. There’s plenty of 15um energy coming from a blackbody with 10um peak frequency. You obviously have no idea what a continuous blackbody spectrum looks like. What you’re saying is like saying no colors of visible light come from sun except for yellow because that’s the peak emission frequency of a 5200K blackbody source. Ridiculous misunderstanding.

Myrrh says:
February 14, 2011 at 4:06 am
Cal says Feb 14, 12:49 am, Slacko says, Jim says
Sort it out, will you.
http://www.wisegeek.com/how-does-infrared-heat-work.htm
“To observe how infrared heat works, the heating and cooling of the earth is probably the most helpful example. Apart from driving all weather events and patterns, as well as ocean currents, infrared heat from the sun is what the Earth during the day, and it is what the ground gives off at night after the sun sets. It is interesting to note that while the sun does emit a huge amount of infrared heat, only about half of the heat we feel on the ground is from direct infrared radiation from the sun. The other half comes from energy from visible light that is absorbed by objects on earth, and then emitted later as infrared heat.”
So which is it?
I accept that I should have said that the sun radiates at all wavelengths from UV to far infrared, but that the peak is in the visible region. Moreover a lot of the incoming energy in the infra red region is absorbed by CO2 and H2O in the atmosphere and is then re-radiated downwards (and upwards ultimately to space) in exactly the same way as the energy radiated by the surface. UV is also absorbed (particularly by ozone) but the peak energy at the surface is still in the visible region of the spectrum. So at night all the infrared radiaton is from CO2 and H2O and during the day the majority is. However the main point I was making was about infra red radiation at night.

Izen.
Thanks for the reply.
Clouds keep the earth warmer (or a given portion of the earth) by preventing heat from escaping. In fact, convectional currents can rise a long way into the atmosphere before they lose their buoyancy. Something like a hot air balloon does.
This uplift, and cooling of air is what causes most weather. Cumulonimbus clouds are often 10,000 metres in height from surface.
actually, watervapour above this level acts as an absorber of radiation. the so called greenhouse effect.

P Wilson says:
February 14, 2011 at 8:04 am
“How hot can this 15 µm -80 Centigrade IR heat anything?”
Because it sits between a 15C ocean surface and the -253C of the cosmic void. It doesn’t heat anything. It slows down the rate of cooling by interposing something warmer than the black of space between the surface and the black of space. This isn’t rocket science. It’s about as difficult to understand as is understanding why sitting a cup of hot coffee on a block of dry ice versus a block of water ice. In both cases the coffee won’t get any hotter but it will cool a lot faster sitting on the dry ice versus sitting on the regular ice. Or even better hot coffee in an insulated thermos vs. a non-insulated thermos. In both cases the coffee is going to get cooler but the insulated thermos will slow down the rate of cooling. To get an even closer analogy consider an insulated versus and uninsulated hot water heater where the heating element is turned on once a day for a set period of time. The insulated water heater will have a higher temperature because the amount of energy added to each one is equal but the rate of escape of that added energy is lower for the insulated vessel. The end result is the water in the insulated vessel will have a higher maximum and minimum daily temperatures. In the case of the ocean it’s the sun doing the heating on a daily basis and greenhouse gases are the insulators which slow down how fast the ocean cools when the sun isn’t heating it. As Ernest Rutherford said “if you can’t explain a theory in physics such that a bartender can understand it then the theory is probably wrong”. A bartender can understand the difference between an insulated and uninsulated thermos. Why can’t you?

“And the problem that all these scientists have is that they will never be able to test if their theories are correct, because the time spans are too long”
Is that so? What if we had a month off for CO2 emissions as a globe, with CO2 output deliberately reduced by say 30%. This would create a point of inflexion in our CO2 output which in theory should then be followed by a point of inflexion in rising temperatures, thus proving AGW theory and demonstrating cause and effect. It would then allow us to go further and estimate the actual impact of given increases in CO2. Got to be worth doing just as a global experiment before making any solid commitments to changing our habits.
(Well in theory, in practice I guess it would just get lost in the noise of normal weather patterns which would only prove the futility of the whole AGW nonsense)

I didn’t mean to suggest that heating the surface more would cool the air!
Just that returning energy to the surface provides more of a direct avenue for escape than if it relied only on radiation from GHG’s.

Dave Springer says:
February 14, 2011 at 8:54 am
i said
“actually, watervapour above this level acts as an absorber of radiation. the so called greenhouse effect”
Water vapour is indeed invisible.
the above comment was a contradiction of Izens, who said that water vapour higher than clouds have no effect. He said “Above the main low cloud layer water vapor is much less important as an atmospheric absorber/emitter.”
I think you’ve got it muddled somewhere, although if you wish to trace a source of the confusion between clouds and water vapour, I suggest you consult Izens first.

“”””” P Wilson says:
February 14, 2011 at 9:10 am
Dave Springer says:
February 14, 2011 at 8:21 am
Largely irrelevant comments re c02 though correct ones regarding the sun. However, the argument is that c02 is largely irrelevant to the climate, since most heat escapes via convection and conduction, hence the quick cool down at night. this cooldown, and corresponding cool upper layers show just how quickly this takes place. Nothing to do with the SB equation. To do with observed phenomena
the main reason is that there is no heat being generated, or stored by greenhouse gases, and so back radiation doesn’t occur. Even if it did, the quantities would be almost infinitessimal.
In your later analogy however, it is convection that is being vastly reduced in a thermal flask, which prevents quick cooling.
this convectional trapping process does not occur with outgoing IR radiation through c02 or any other ghg.
however, even at ground-10,000 metres, what c02 does is so infinitessimally small that it might as well be factored out of climate projections.
at 15microns peak, that makes not an iota of difference to atmospheric temperatures. Besides, gases are not blackbodies, and are 3 dimensional. Radiative equations can’t be applied to them (air has a very poor conductor), and so is irrelevant to climatology. With ghg’s, *blocking* operates in all directions, so doesn’t make any difference to the atmospheric heat content.
if you’re talking about the shoulders of c02, then at this level there is more nitrogen and oxygen per CO2 molecule in this area. Dilution reduces the temperature increase per unit of energy. I don’t know about other readers; but I have absolutely no idea who said what, in this joint effort by P-Wilson, and Dave Springer.
Perhaps, P. Wilson, being the outermost poster, can find some simple methodology to separate what he is citing from Dave Springer (if anything) and what is the product of his own thoughts.
I often see people ascribe whole rafts of stuff to me; when I never said one word of what they posted.
Trying to italicize things doesn’t do a thing, since the browsers can make mincemeat out of font twiddling.
So I dunno P. Wilson; just what did you add if any to what Dave said if any ?

George Smith
dave Springer maintains that ghg’s – particularly c02 slows the rate of cooling of the atmosphere, and uses the analogy of a thermal flask (which limits conduction and convection.
i’m arguing that c02 doesn’t make much measurable difference to atmospheric heat content and cool rate

steven mosher [February 13, 2011 at 3:39 pm] says:
“yup, but there is more to it than that. If you want to do IR design today ( of sensors, or counter measures or stealth technology) the physics you use is the same physics that many skeptics deny. good thing we don’t let them design the machines that our safety as a nation depends upon.“
Got out of bed the wrong side today Mosh??? Only an idiot would think that tarring all sceptics with the same brush is a sensible way to have a useful debate.
My own take on this is simple. Although lab experiments show CO2 could raise Earth’s overall temperature by a tiny amount, the IPCC’s predictions of catastrophic temperature increases produced by carbon dioxide have been challenged by many scientists and found to have no substance in the real world.
The importance of water vapour is frequently overlooked by environmental activists and by the media. The large temperature increases predicted by many computer models are non-physical and inconsistent with results obtained by basic measurements – much scepticism is warranted when considering computer-generated projections of global warming when these same models cannot even predict existing observations.

A C Osborn says:
February 14, 2011 at 9:40 am
Oliver Ramsay says:
February 14, 2011 at 8:51 am “In fact the warmer the surface becomes the more the energy will be radiated to space without bouncing around in the atmosphere.”
WUWT?
So the surface has a direct connection to space then?
—————
Yes

Mikael Cronholm says:
February 13, 2011 at 9:56 pm
Ian W says:
February 13, 2011 at 12:35 pm
When water vapor in the atmosphere condenses into liquid water and then changes state again and becomes ice, it gives off latent heat for both state changes.
Does that latent heat release follow Stefan-Boltzmann’s radiative equation ?
No Ian, latent heat is not really related to S-B.

So if you consider all the clouds and it is estimated that 62% of earth’s surface is covered by clouds – the amount of energy released as latent heat is huge. Yet people persist in working out the amount of heat leaving the surface using Stefan-Boltzmann radiation equations. This is obviously incorrect.

izen says:
February 14, 2011 at 8:15 am
Some energy leaves the SURFACE by convection, but it does not get very far.
It is not clouds that block it… strange idea!
Its the adiabatic lapse rate.
Convection can only move air until the increased bouancy from the lower number of molecules per cubic metre is offset by the lower density with increasing altitude. It is the lower density of the atmosphere with altitude that blocks convection.
The low altitude of most clouds indicates that the temperature falls below freezing just a few Km above ground level and the atmosphere regains that latent heat of evaporation well below the tropopause. Above the main low cloud layer water vapor is much less important as an atmospheric absorber/emitter.
Well I don’t know about ‘not getting very far’ 60,000ft or more in the tropics is the level of the tropopause (the top of the convective atmosphere) and in the Inter-Tropical Convergence Zone (ITCZ) the cloud tops of towering storms are (by definition) up to that level. (A recent Northwest Airlines flight experienced liquid rain hitting the aircraft in cruise above 30,000ft in a storm between Hong Kong and Tokyo despite the ambient outside-air-temperature being well below zero. The rain froze into ice on hitting the airframe) The height of the cloud tops all depends on why the clouds are there.
Humid air is more buoyant than dry air, so just being more humid is enough for a volume of air to start convection. Drier air sucked in will then pass over the wet surface and Henry’s law applies and more water will evaporate into the dry air cooling the surface. No external heat source is required. As the humid air rises the air temperature will drop at the wet adiabatic lapse rate and water will start to condense around nucleation particles and form clouds. This type of cloud with a gentle wind will become the low stratocumulus over oceans and coastlines. And each and every cloud droplet has taken heat from the surface and radiated it as it becomes a droplet and again when it becomes ice.
With the application of tropical heat and humidity convective storms develop every day some towering ten miles high into the atmosphere. If the conditions are conducive these storms merge and the Coriolis force on the air being rapidly drawn in at the base of the storms starts the winds in the storm system to rotate. There is a lot of discussion of the ACE index here, but to put it in perspective, the amount of energy released by a hurricane can be calculated based on the latent heat emitted and / or the kinetic energy.
An average hurricane in a day transfers latent heat equivalent to 200 times the world-wide electrical generating capacity.
http://www.aoml.noaa.gov/hrd/tcfaq/D7.html
As confirmed in response to my question at the top of this thread, the temperature of the cloud has no bearing on the amount of latent heat being released. The heat being released is linked to the amount of water changing state and the latent heat of that state change.
The missing heat is almost certainly in the misunderstood and underestimated hydrologic cycle that is ignored in favor of a simple Stefan-Boltzmann radiation equation.

The question posed early on this thread from KLC; ” . . . From your point of view as an IR expert, does this aspect of the global warming theory make any sense?”
RE: “. . . notorious Ternberth/Keihl energy balance schematic (as shown in Figure 1 of this paper: http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/TFK_bams09.pdf ), you see the back radiation is determined to be very significant…”
Maybe I missed it but was there a summary or (for want of a better term) a consensus from the posters here that can answer this with some authority? MC replied he had issues with the numbers used. I was wondering what others thought re: reasonable numbers if those referred to (fig 1) are not reasonable.
MC also noted, “Every question answered raises a few more, which grows the confusion exponentially. ”
I was hoping to clear up some confusion on my part.
-Barn

i see. That was entirely my post. As a response to Dave Springer. I just cut and pasted his name and time to show what post I was replying to
Hope that clears things up

George E. Smith says:
February 14, 2011 at 10:28 a
“Clearly the ten years, that I formally studied Physics in School, plus the subsequent 50 years of using it daily in practice to accomplish things; was not enough for me to come across that jewel of knowledge, that gases do not radiate according to the radiation laws.”
of course they do, as only you would know. I’m referring to the SB equation in particular as applied to c02, and the fanciful results on paper that it generates. I think you’ve implied before that except for a tiny fingerprint of black body radiation, most radiation evades c02 in its escape to space.
Before energy escapes into space through radiation, it doesn’t matter whether the energy is in contact with CO2, water vapor or nitrogen.

Steeptown mentioned:
…it is evident to me that the radiative efects of CO2 in the atmosphere are of 2nd or 3rd order compared to the radiative, convective and latent heat effects of H2O.
Well, when do 2nd order effects become important? The problem with increasing CO2 in the atmosphere is the ever increasing 2nd order effect. So a little bit of energy doesn’t escape. No big problem. But, if the effect is compounded, which appears to be the case for CO2, suddenly a little bit of energy becomes a lot of energy. When do we care?
Water in the atmosphere has two very different properties versus CO2. First, the amount of water in the atmosphere is not likely to double unless there is a major change in the atmosphere. So even if H2O is a first order effect, the much smaller changes in the amount of water is not going to be significant. However, CO2 is increasing fairly quick. And a doubling or possibly tripling the amount of CO2 is very real so the second order impact is likely to be much larger than the small deviations of the first order impact. Second, CO2 is throughout the entire atmosphere. Sure, it is only 0.04% of the atmosphere. But if we look at the entire atmosphere, not just the surface, water is only 0.4%. Doubling or tripling CO2 is now ~0.1 %. Suddenly CO2 is not that small after all.
Something else folks seem to be forgetting with CO2 is the bands it absorbs. In particular, it is absorbing in bands that water is not. At lower levels of CO2, a sufficient amount of LW radiation was escaping to provide an energy balance. With the increased amount of CO2, the balance has been upset and the Earth is trying to reach a new equilibrium.
Some folks are very taken with Mr. Cronholm’s one comment:
For a theory to be scientifically proven, it has to be stipulated and tested, and the test must be repeatable and give the same results in successive tests for the theory to be proven.
This may be true, but we only have one planet. We don’t have an alternate Earth that we can play with to see what happens. Also, tested does not necessarily mean run in a lab or a model. Consider evolution. We don’t “test” evolution, we look at the available data and the composite result from this evidence is the fundamental reasons for evolution. Climate change is similar: we look at temperature, CO2, extended growing seasons, northern and southern boundaries of migrating birds and insects, extreme weather events, receding glaciers, etc.
One comment that has been discussed time and again is that in the geological record, an increase in CO2 occurs after an increase in temperature. Fine, let’s assume that is true. The problem we have is the measurements we are making now show CO2 increasing and temperature following. What does it mean? Simple: a different mechanism is now responsible, not the natural processes we have been able to identify from past changes.
Of course, there could be another natural phenomenon we have not found/discovered. But as Dr. Alley from Penn State has pointed out: we built the satellites, we made the measurements, when someone disagreed we made new satellites and new measurements. We have spent billions of dollars and so far the overwhelming evidence is in support of AGW.
Think of it like Children’s Hospital. The doctors there have one job: to put themselves out of a job. If they could solve all the medical issues they see, they would no longer be needed. And that is actually their goal! They don’t want kids to suffer. Do people really think climate change scientists want AGW to be true? If they are right, the end result is really bad.

Don V :
February 14, 2011 at 1:47 am
Thank you Don, well thought out comment!
Found not a single thing within I would argue about.
You have a clear mind. Could we talk some physics here? I have one big question I need some help answering (or try to answer at least, and, it’s on a very simple logical level).

Ian W says:
February 14, 2011 at 10:06 am
“As confirmed in response to my question at the top of this thread, the temperature of the cloud has no bearing on the amount of latent heat being released. The heat being released is linked to the amount of water changing state and the latent heat of that state change.
The missing heat is almost certainly in the misunderstood and underestimated hydrologic cycle that is ignored in favor of a simple Stefan-Boltzmann radiation equation.”
The ‘Science of Doom’ site linked to from here (top right of page) has a good discussion of some of these issues.
The amount of energy transported by latent heat changes is complex, there is one simple way to quantify it however. The total global yearly rainfall is a direct measure of how much energy was moved by evaporation and condensation in the hydrological cycle.
But the first LoT kicks in. The energy is still around. The only way it can get of the planet is by radiating IR photons into space. All the hydrological cycle can do is move the location of that emission around. That evens out the temperature so that water does not boil at the equator and can melt at the poles, but the same amount of energy has to leave the planet. Otherwise it will warm until the S-B T^4 relationship increase the emissions enough to compensate.

You accused me of “tarring all sceptics”
There is a reason why I chose the word “many”
There is a reason why I did not use the term “all” or “Most”
The reason was to trap idiots who are not careful with words.
Steve, That may well be the case but seeking to trap idiots is no more valid than your rivals statement. I believe also that your comment ‘that most skeptics deny’ is also and POSSIBLY incorrect. I know I feel somewhat agrieved because while I am a skeptic (and a physicist) I understand well enough the ‘science of CO²’ but I have never been convinced that the phrase that ‘increasing CO² causes global warming’ has ever been proven (show me where) or is in anyway true. Suggest you read those words very carefully. :))

frog, jim,
the details show in kt97 that the assumptions are 100% optical thickness for the two main cloud types and 50 or 60% thickness for the 6% coverage contributor. The 62% result they come up with is assuming 100% thickness with random overlap. It does seem to agree well with what little is known of the actual coverage, which can vary substantially over time, something like over +/- 5% as I recall. That also leads to an albedo variation of around 5% and a peak to peak difference in reflected incoming light power of about 10 w/m^2, far more than a mere co2 doubling.

“”””” Ian W says:
February 13, 2011 at 12:35 pm
When water vapor in the atmosphere condenses into liquid water and then changes state again and becomes ice, it gives off latent heat for both state changes.
Does that latent heat release follow Stefan-Boltzmann’s radiative equation ? “””””
Latent heat and anything to do with heat, is a property of physical matter; it has nothing to do with Electromagnetic Radiation; so it has nothing to do with the Stefan Boltzmann equation.
EM radiation can go anywhere it wants to; heat can’t.

physics schymisics,
real world
When CO2 levels were 4000 ppm – we had an ice age
when CO2 levels were 3000 ppm = we had an ice age
when CO2 levels were 2000 ppm – we had an ice age
and here we are wringing our hands and wetting the bed over 390 ppm……………….
real world says the only tipping point is when CO2 levels get in the thousands, we can have another ice age……………..

“Sensor operator says:
February 14, 2011 at 11:52 am
Think of it like Children’s Hospital. The doctors there have one job: to put themselves out of a job. If they could solve all the medical issues they see, they would no longer be needed. And that is actually their goal! They don’t want kids to suffer. Do people really think climate change scientists want AGW to be true? If they are right, the end result is really bad.”
Sensor, I don’t have to THINK that is what some climate scientists think. Phil Jones actually stated it in his e-mails.

Infrared is Heat, or rather far and mid is heat. Near infrared is not felt as heat, think remote control. You’re not going to get warm by flicking your remote at yourself.
Visible light and UV do not feel hot, they are cool. UV doesn’t penetrate very far into the body, it tans, or burns, the skin – can do so even on cloudy days as Robert Clamenzi says (Feb 14, 11:23 am).
We receive IR here on earth from the Sun. Why is this excluded in AGW literature?