CO2 does not Black Body Radiation make

From the “Oh Dear!” department of unsettling science…

It would seem that the basic notion of CO2 as an emitter of infrared radiation causing ever more “back radiation” to heat the planet with increasing temperatures, the very foundation of the Global Warming runaway greenhouse hypothesis has, er, “has issues”. Which is a polite way of saying it is deeply flawed.

It looks like the only thing with black body radiation is a real black body and that transparent things, like gasses, are not quite the same. In particular, CO2 likes to heat up instead of emit a photon. Now that also means they will tend to hold onto any energy input long enough to whack into one of the other gasses in the air and thermalize any IR they absorbed. Which in turn means that the bulk of the air (Nitrogen, Oxygen, Argon, Water Vapor) will be holding that energy, not the CO2. That, then, means were are back to “hot air rises” and all the convective processes of the troposphere as “what matters” and that “back radiation” just isn’t going to cut it. All the calculation and hand waving based on “black body” and “back radiation” needs a bit of a do-over.

This paper is the key, but a bit thick to read:

http://ptep-online.com/index_files/2014/PP-38-05.PDF

Way down at the end it says:

The belief that arbitrary materials can sustain black radiation
always results from an improper treatment of reflection
and energy influx. In Max Planck’s case, this involved the
mandatory insertion of a carbon particle within his cavities.
This acted to drive reflection. In the construction of laboratory
blackbodies, it involves departure from thermal equilibrium
as the inflow of energy enables the emissivity to drive
the reflection. In the belief that optically thick gases can emit
blackbody radiation [16], it centers upon the complete dismissal
of reflection and a misunderstanding with respect to
energy inflow in gases
[17].
[…]
In fact, many cavities can never be filled with
black radiation, even if one attempts to drive the reflection
term. That is because certain materials are not conducive to
emission and prefer to increase their temperature rather than
drive reflection. Arbitrary cavities do not contain black radiation,
and that is the measure of the downfall of Kirchhoff’s
law.
Taken in unison, all of these observations, even dating
back to the days of Kirchhoff himself, highlight that the universality
of blackbody radiation has simply been overstated.
The emissive characteristics of a cavity are absolutely dependent
on the nature of the cavity walls (see [13], [14, p. 747–
759], and references therein). This has broad implications
throughout physics and astronomy.

A more approachable write up of the whole issues is here:

http://hockeyschtick.blogspot.co.uk/2014/05/new-paper-questions-basic-physics.html

However, climate scientists and climate models instead falsely assume that the Kirchhoff, Planck, and Stefan-Boltzmann laws can be applied to greenhouse gases and that they behave as blackbodies. Dr. Robitaille shows prior work from Hottel et al demonstrating that the emissivity of both of these greenhouse gases decrease with temperature [i.e. they become less of a ‘greenhouse gas’ as temperatures increase], the opposite of the climate science assumption that greenhouse gases increase emissivity and absorptivity with temperature. For conservation of energy, emissivity must equal absorptivity for all materials and gases, therefore increases in temperature decrease both emissions and absorption of infrared radiation by the greenhouse gases water vapor and CO2, i.e. they become less ‘greenhouse like’ gases as temperatures increase, a self-regulatory mechanism that suggests less climate sensitivity to CO2 with increasing temperature.

It is well worth reading all of both of those links.

I came to this chain of links via a comment by Rogerknights on WUWT here:

http://wattsupwiththat.com/2014/05/24/open-thread-weekend-21/#comment-1645063

rogerknights says:
May 24, 2014 at 5:59 pm (Edit)

Steve Oregon says:
May 24, 2014 at 4:47 pm

A curious question.
If Mann and Trenberth discovered iron clad scientific evidence that CO2 emissions were meaningless to the climate would they tell anyone?

We’ll have a clue in their reaction to this paper:

Latitude says:
May 11, 2014 at 1:46 pm

Thursday, May 8, 2014
New paper questions the ‘basic physics’ underlying climate alarm

A forthcoming paper published in Progress in Physics has important implications for the ‘basic physics’ of climate change. Physicist Dr. Pierre-Marie Robitaille’s paper(s) show the assumption that greenhouse gases and other non-blackbody materials follow the blackbody laws of Kirchhoff, Planck, and Stefan-Boltzmann is incorrect, that the laws and constants of Planck and Boltzmann are not universal and widely vary by material or different gases. Dr. Robitaille demonstrates CO2 and water vapor act in the opposite manner of actual blackbodies [climate scientists falsely assume greenhouse gases act as true blackbodies], demonstrating decreasing emissivity with increases in temperature. True blackbodies instead increase emissivity to the 4th power of temperature, and thus the blackbody laws of Kirchhoff, Planck, and Stefan-Boltzmann only apply to true blackbodies, not greenhouse gases or most other materials. The significance to the radiative ‘greenhouse effect’ is that the climate is less sensitive to both CO2 and water vapor since both are less ‘greenhouse-like’ emitters and absorbers of IR radiation as temperatures increase.

http://hockeyschtick.blogspot.co.uk/2014/05/new-paper-questions-basic-physics.html

Somehow I think a few folks are going to be very unhappy about that paper…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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35 Responses to CO2 does not Black Body Radiation make

  1. David A says:

    The study raises some cogent questions I have asked.
    The ratio of how often a GHG molecule conducts received LWIR to other molecules, verses radiating said energy, has been a subject of my curiosity for some time. Does said ratio change with elevation? After a GHG molecule releases its energy, via either radiation or conduction, is it then cooler then the L.T.E.? If so can it then receive conducted energy from a non GHG and radiate that energy to space? If a GHG molecule does receive energy from LWIR from the surface, and then conducts it to a non GHG molecule verses radiating said energy to space, is this not still warming as it increases the residence time of the energy involved?

    It appears to me that GHG molecules in multiple different ways can warm or cool, and I doubt anyone knows the ratios that these process happen at in the real world. However the net affect of the interchange of conduction, convection, and radiation may be close to Newtonian. (For every action there is an equal and opposite…)

  2. If a so-called Greenhouse Gas Molecule were in fact to be radiating energy as much as stated, then it would act as a coolant. The direction of radiation is random. At any given height above the Earth’s surface, there will be more sky to radiate than ground (at ground level the steradians of sky and ground would be equal on a perfect sphere, and as you get above ground the solid angle of the sky gets bigger). The net effect of this will be to radiate more energy towards space than the ground, and as you get higher up in the atmosphere this effect will augment.

    There is thus a fallacy built into the basic argument. It wouldn’t even work with a flat Earth.

    Hey, folks, we need to stop producing CO2 in order to avoid the next Ice Age coming! Let’s tax Carbon even more!

  3. David A says:

    Simon, as I understand it the warmist know this very well. They are simply saying on balance a GHG molecule extends the life of a parcel of radiant energy leaving the earth. While that radiating energy sometimes stay within our earth, land, and ocean system longer, additional insolation enters, thus net warming.

    What I have never seen is an explanation of how much in fact this happens, and how often, nor a engineering style analyses of how conduction & convection enter into the picture, and so cancel the warming. It is clear to me that under numerous scenarios GHGs warm and or cool, and or simply act as other molecule conducting and being conducted to, as well as playing a non GHG role in convection as well. It varies with elevation and latitude, over the oceans and over the dry regions, sometimes increasing energy residence time, sometimes decreasing, sometimes radiating to space conducted energy from other non GHG molecules, (cooling) sometimes redirecting energy back to the earth via conduction or radiation, (warming)

    Also the ratio of these interchanges would not stay the same, but vary depending on the percentages of GHG molecules within the atmosphere. (In essence the fewer GHG molecules, the more the role of conduction and convection play apart in removing energy.) Both conduction and convection are a slower process then radiation.

  4. omanuel says:

    The political decision – that “CO2 causes global warming” – will yet find scientific justification.

    That is the way post-1945 government science operates.

  5. David – I’ve seen “demonstrations of the greenhouse effect” where a heat lamp was shone into closed volumes of various gas mixes and the temperature rise measured. Convection was thus eliminated – somewhat of a straw man. Given the quantity and variability of the water-vapour in the atmosphere relative to the CO2 and Methane, I can’t see the link to CO2 alone being valid anyway.

    As EM put eloquently a while back, the total quantity of CO2 in the air above a square metre is sufficient to produce a few kilograms of vegetable matter (he talked of a stick about a foot long and an inch diameter from a square foot, IIRC), and that’s if it’s all used up. I recall reading in the AGW literature that any CO2 we put up into the air will be there for centuries and cause problems to our grandkids. Looking at the mass of vegetable matter being produced each year, I’d be surprised if the cycle time was much over a year. There are maps of CO2 concentration, but they are of necessity somewhat sparse, since there’s a lot of volume of air and sensors will be relatively few and far between. It will obviously also vary with height (plants and most producers being on the ground) and with the amount of photosynthesis going on (how sunny it is and whether there’s enough water in the ground to keep the leaves sufficiently moist), and what’s upwind. Measuring it in Hawaii close to a rumbling volcano may not be the most indicative of the concentration elsewhere.

    I suspect that the full effects of the various GHGs (including water-vapour) will be too complex to model (and thus predict) for quite a while yet. As you say, the net effect is likely to be different depending on exact conditions at any point. Given the difficulty in predicting weather more than a few days ahead, it will be harder and require more information to model all the gases and check the predictions against reality.

    The relative rates of conduction, convection and radiation would need to be measured. The speed of propagation of radiation depends on the jump distance (how far the radiation travels before being absorbed) and the dwell time – how long before it gets re-radiated. As a gut-feel, seeing how easy it is to focus the sun’s heat with a magnifying glass and see a well-defined burn spot, I’d say that the absorption rate isn’t very high and that the dwell-time is likely fairly long, I’d thus expect convection and winds to be the fastest actual transport of energy in terms of joules/m/s.

    I think what annoys me about the AGW idea is the gross oversimplification down to “it’s CO2 and it’s your fault it’s happening”, when the cause and indeed the effect are not simple and not understood. What annoys me maybe more is that, before I actually looked at the data, I accepted it as a given thing since it is so well supported in the media and by governments. Mostly, consensus is at least a safe option, but in this case it’s way off.

  6. Serioso says:

    Several things I noticed: The Robitaille paper was submitted to “Progress in Physics” on April 28th and accepted on April 29th, which suggests it was not peer-reviewed per journal policy. The journal itself is considered to be out of the mainstream.And, third, anyone who thinks Planck and Kirchoff can be invalidated by a couple of papers out of a very minor research lab is quite possibly deluded. True, miracles occur, but one should always set one’s bull detector on maximum sensitivity when checking them out. The chances that Robitaille is completely wrong are very high, to say the least.

  7. Ben Wouters says:

    It gets even more interesting:

    In this solar radiation spectrum we can see the large “missing” parts in the (red) surface spectrum.
    Solar IR is absorbed by H2O and a little by CO2 (look very careful around 2000 nm)
    Very doubtful IR from the surface will heat the two more than the sun has already done.

  8. Pouncer says:

    Those who promote the theory of CAGW implicitly assume that CO2 is a proxy for all the human factors affecting climate. If we didn’t burn fossil fuels, (they would argue) we couldn’t deforest the Amazon. if we didn’t burn fossil fuels, we wouldn’t deposit soot on the ice caps. If no fossil fuel, no machinery would till new ground for new farms raising new sources of dust. And etc etc. The CO2 is thus a proxy for what Hansen calls “Business as Usual” — BUSINESS and free markets being the real target of regulators, not the invisible trace gas. Win the argument and empower a select elite to “regulate” CO2 by tax, or cap-and-trade, or any other means, and all other business as usual or as new-and-improved comes into the mix.

    In the US, the EPA has already admitted that CO2 is a camel’s nose in the tent of “everything”.

    http://m.us.wsj.com/articles/SB10001424052702303480304579580222346275190?mobile=y&mg=reno64-wsj

  9. E.M.Smith says:

    @Simon:

    I think you are talking about this posting:
    https://chiefio.wordpress.com/2010/10/10/got-wood/
    My favorite image from it being a 13 oz chunk of wood on a 1 ft sq tile. That represents all the CO2 above that square on into space. So grow that much wood, you have sucked dry that much air…

    There’s also one of a carefully selected (smallish) corn stalk of the same weight leaning against a tree…

    Whenever I think of folks nattering about CO2 sequestration methods and capture I just think of a corn stalk or tree and give a big sigh for the stupidity, so thick it burns…

  10. Another Ian says:

    E.M.

    Have a look at the comments by “Turnedoutnice” here

    http://joannenova.com.au/2014/05/newton-einstein-watson-and-crick-were-not-peer-reviewed/

  11. EM – yes, thanks, that was the post (longer ago than I’d thought). That made a big impression on me at the time, and I’ve since recalculated it a couple of times. My vines and bit of woods mean that I’m generally absorbing more CO2 than I produce. Since I burn the vines when they finally die (they’re about 79-80 years old) and burn trees that fall and thus return the CO2, the small amount of diesel I burn doesn’t increase the CO2 level much. I should be burning more to do my bit to improve the farming yield, but it costs too much….

    That post really put the lie to the idea that CO2 would have a residence time of centuries in the atmosphere, and so instead we’re using it almost as fast as we’re producing it. Raise the level, and the rate of absorption also increases (and farming yields go up too).

    It’s nice to put real numbers on things.

  12. CO2 during the day gets warmed and goes up, on high altitude , where cooling is very efficient. Caveman did know that; warmed CO2 goes up – that’s how they invented the chimney… unfortunately, now that is a taboo..

    After sundown, CO2 loses the benefit of sunlight -> cools fast / shrinks and falls down to the ground as ”colder” that’s when the trees, crops are gorging themselves on the essential molecule of CO2

    3] CO2 doesn’t ”radiate” heat down towards the ground, because: every molecule of CO2 in the atmosphere is surrounded by many atoms of O2&N2 – they are perfect insulators: http://globalwarmingdenier.wordpress.com/2014/04/28/global-warming-or-climate-change/

  13. Richard111 says:

    There is an interesting graph shown here: http://accessengineeringlibrary.com/graph
    from Perry’s 8th Edition. It shows the EMISSION levels of CO2 and H2O at 1,500K !!!
    They have to push it to that temperature to show the full range of emissions. Note how H2O almost completely covers the CO2 emissions. Just the 4.3 micron band from CO2 is in the clear. Another point not made clear is that if a ‘greenhouse gas’ is emitting any band of radiation because of its current temperature it CANNOT absorb the same range of photons again to increase the temperature. Duh!

  14. R. de Haan says:

    Didn;t you listen to Piers Corbyn: Tinkering Around With Nonsense Doesn’t Work
    http://stevengoddard.wordpress.com/2014/05/27/rise-in-co2-equivalent-to-packing-an-extra-seven-people-into-the-bernabeu/

  15. If a CO2 molecule absorbs IR from the ground then it becomes warmer than non GHG molecules around it, passes energy to them by conduction and creates a parcel of air that rises higher.

    If any parcel of air becomes warmer than the lapse rate temperaure at its height it must rise.

    Any GHGs at a temperature that is too high for their position along the lapse rate slope lose more energy to space than they receive from the ground which in due course results in cooling and descent.

    So, half the time a CO2 molecule will be higher than it should be relative to the lapse rate slope and half the time it will be lower.

    The net effect is zero.

    If the net effect is non zero then the CO2 molecules just spend more time above or below their correct position along the lapse rate slope until the net effect does revert to zero.

    Adiabatic uplift and descent neutralises the thermal effect of GHGs by converting kinetic energy to gravitational potential energy (GPE) and back again as necessary to maintain system stability.

    Energy in the form of GPE cannot be used to radiate to space. It is instead used to maintain the height of the atmosphere off the ground.

    GPE is not heat and does not radiate but it leads to a higher surface temperature than S-B predicts because it converts back to kinetic energy (heat) on the descent phase of the adiabatic cycle.

    The surface temperature enhancement is therefore nothing to do with radiation. Instead it is due to conduction and convection leading to the adiabatic energy exchange between surface and atmosphere.

  16. AlecM says:

    Some key issues: the fall off of emissivity with temperature is an artefact of Hottell’s apparatus. Essentially, higher temperature means lower gas density and in the dimensions of the apparatus, it ceases to be self-absorbed.

    As for the ‘new physics’, it’ s based on the idea of ‘photons’ banging around. That’s not how IR works – a photon does not exist until it’s energy is transferred to or from mechanical energy.

    Just remember that Kirchhoff’s Law of Radiation means for gases at local thermodynamic equilibrium there can be no thermalisation of GHG-absorbed IR energy – the same has to leave that gas volume and can only thermalise at heterogeneous interfaces. There is no ‘back radiation’; that is to confuse the atmosphere’s Irradiance, a potential energy flux, with a real flux.

    The IPCC physics is so wrong as to be embarrassing.

  17. The distinction between heat energy which is available for radiation and mechanical energy tied up in gravitational potential energy which is not heat and therefore not available for radiation seems to be the critical issue.

    AGW theory does not recognise non radiating energy which is tied up in the ongoing mechanical process of holding the atmosphere off the surface.

    Yet it is that energy, varying as necessary via changes in convection, which holds the balance between radiation and conduction within the system.

    To maintain balance between energy in and energy out the total amount of energy tied up in the system must remain the same and the only ways energy can be transferred is by radiation or conduction.

    So, if the balance between radiation and conduction does not produce exactly the right amount of outgoing energy then the rate of convection (and the height of the atmosphere or a vertical portion of it) must change in order to restore balance.

    Exactly as per the Gas Laws which have no term for the radiative capability of constituent gases because the net thermal effect of radiative capability is zero.

    If radiative capability did have a net thermal effect then either the Gas Laws would be invalid or an additional term would need to be added.

    QED.

  18. Robert Austin says:

    David A says:
    26 May 2014 at 7:44 am

    The ratio of how often a GHG molecule conducts received LWIR to other molecules, verses radiating said energy, has been a subject of my curiosity for some time. Does said ratio change with elevation?

    This goes to the very heart of the significance of the tropopause (top of troposphere). At this altitude (about 0.1 bar) the mean time between collisions of an excited greenhouse gas molecule and its vastly more common non radiative neighbours is reduced to the point where a significant portion of excited greenhouse molecules can radiate to space. In other words, at this pressure, the atmosphere is no longer opaque to certain bands of IR as it is in the lower troposphere. Back radiation and residence time are simplistic analogies that really do not portray the role of greenhouse gases in an elegant and proper manner. Having a significant portion of the radiation to space be emitted by radiative gases high in the troposphere rather than just from the earth’s surface, clouds and aerosols is what enables the lapse rate structure of our troposphere. And wonder of wonders, we can see similar lapse rate structure at comparable atmospheric pressure in the atmosphere of Venus, an atmosphere bizarrely different from Earth’s, but physical principles still reign.

  19. Robert Austin says:

    “assumption that greenhouse gases and other non-blackbody materials follow the blackbody laws of Kirchhoff, Planck, and Stefan-Boltzmann is incorrect”

    This is incredible, if true. Do some “accredited” scientists actually advocate that gases (either radiative or non radiative) act as blackbody radiators and absorbers? I have no experience this idea being promulgated even by the most vacuous of warmists. Or is it hidden in the architecture of their arcane models but never expressed aloud?

  20. omanuel says:

    E.M. Smith, your keen analytical mind helped skeptics win the AGW debate. But seething anger for sixty-nine years of government deception threatens to erupt now:

    http://theinternetpost.net/2014/05/26/sade-why-cant-we-live-together/

    http://theinternetpost.net/2014/05/26/did-virtually-every-american-who-died-in-a-war-die-for-a-lie/

    For that reason I urge you and other skeptics to tell the public that world leaders had reason to fear worldwide nuclear annihilation in 1945 when they secretly agreed to forbid public knowledge of energy in cores of heavy atoms, some planets, ordinary stars, galaxies and the universe:

    https://dl.dropboxusercontent.com/u/10640850/CHAOS_and_FEAR_August_1945.pdf

  21. David A says:

    re Robert Austin says:
    27 May 2014 at 9:47 pm
    =======================================================
    Thank you and your answer points in the right direction without specifics. (Yet it did increase understanding) Another question if you will. If a GHG molecule sheds its energy through radiation, does it then fall back to the LTE, or to a lower level so that it may then receive energy through conduction, and possibly radiate that energy to space?

  22. Robert Austin said:

    “Having a significant portion of the radiation to space be emitted by radiative gases high in the troposphere rather than just from the earth’s surface, clouds and aerosols is what enables the lapse rate structure of our troposphere”

    That is an assertion I often come across, even from Roy Spencer.

    I don’t see why one needs radiation from GHGs or anything else above the surface to create the lapse rate structure.

    All one needs is uneven surface heating causing some parcels of air in the horizontal plane to be warmer than adjoining parcels. That is inevitable for a rough surfaced rotating sphere.

    In that situation convection inevitably ensues as warmer parcels rise relative to cooler parcels due to density differentials.

    Then, as uplift occurs some of the kinetic energy (heat) converts to gravitational potential energy (not heat) and the temperature of the parcel drops at a rate determined by the strength of the gravitational field.

    From tropopause up to the stratopause the scenario is upset by the ability of ozone in the stratosphere to interact directly with incoming solar radiation but even within the stratosphere there is the Brewer Dobson circulation within which the same principle applies.

    There may well be similar weak and slow circulations which we have not yet measured in the mesosphere and thermosphere.

  23. David A asked:

    “If a GHG molecule sheds its energy through radiation, does it then fall back to the LTE, or to a lower level so that it may then receive energy through conduction, and possibly radiate that energy to space?”

    Lower GHGs absorb IR from the surface until they become too warm for their height along the lapse rate slope.

    They then rise and as they do so their radiation to space gradually comes to dominate until they are too cold for their height along the lapse rate slope.

    They then descend and radiation from the surface gradually comes to dominate once more until they are again too warm for their height along the lapse rate slope and the cycle repeats.

    The potential thermal effect is thus negated by varying the average amount of time that each GHG molecule spends either above or below its correct position for its temperature along the lapse rate slope.

    In effect, kinetic energy and gravitational potential energy are swapped to and fro during ascent and descent so as to maintain system thermal stability.

  24. adolfogiurfa says:

    Please watch this and begin to learn what really drives the weather…..(Have you ever wonder about “winds”, “rain”, “jet-stream”, “pressure”…etc. without CHARGE?

  25. adolfogiurfa says:

  26. adolfo,

    Do you not think that from 09.00 it was solar heating of the surface that caused the storms in an unstable air mass and that the decline around 20. 00 was due to the sun becoming lower in the sky ?

    How do you distinguish beween the lightning that would have occurred anyway in that synoptic situation from any enhancement that might be attributable to your so called ‘electron cloud’ ?

  27. Pingback: New paper says CO2 not a greenhouse gas after all | Climate Conversation Group

  28. tom0mason says:

    Infrared radiation is part of the electromagnetic spectrum and has to conform to all the properties and laws that is evident on that area of physics. If ‘back-radiation’ exists it must be evident in other parts of the EM spectrum surely? Is IR radiation that special, or does ‘climate science’ deliberately conflate and distort the laws that govern transmission of heat energy with IR (radiant) propagation?

  29. Roger Sowell says:

    Even physicists get it wrong, as emissivity does NOT equal absorption per energy conservation law. The true relationship must account for energy storage. Emissivity equals absorption only at steady state, a condition that almost never occurs in nature.

    People invented steady state so we could solve the physics and engineering problems.

  30. omanuel says:

    Today the Congressional Space Science and Technology Committee has a hearing of the UN’s IPCC:

    http://stevengoddard.wordpress.com/2014/05/29/gore-effect-strikes-washington-again/

  31. mkelly says:

    I have mentioned this very thing at several blog sites. There is another thing that is wrong with the CO2 warming idea and that is the notion that CO2 bumps into a N2 molecule and causes it to move faster. i.e. translate. Thus causing warming since T is dependent on speed. There is no way 100% of the CO2 molecules always cause faster translation. I’d bet that statically that half cause slower translation (cooling) and so it is a wash.

  32. omanuel says:

    Did Stalin emerge victorious in the chaotic, but unreported events of August 1945?

    https://dl.dropboxusercontent.com/u/10640850/CHAOS_and_FEAR_August_1945.pdf

    In 1946, George Orwell started writing “1984” As a warning to the public.

    In 1949 Orwell prepared a list of prominent citizens he suspected of being Stalin’s communist agents.

  33. omanuel says:

    Eric Dollard’s observations provide amazing layman’s insight into the actual operation of Earth’s heat source, the Sun:

    http://theinternetpost.net/2014/05/31/the-sun-is-not-what-we-we-have-been-told-eric-dollard-reveals-3-secrets-about-the-sun/

  34. Roger Sowell, who I believe has studied chemical engineering, and surely is aware of the considerable research work of the late Prof Hoyt Hottel (Prof of Chemical Engineering at MIT -the most respected Technical University in the world) is correct about Kirchhoff’s law which clearly states “the emissivity and absorptivity of a surface in surroundings at its own temperature are the same for both monochromatic and total radiation.” Absorptivity of a receiver surface is related to the emissivity and temperature of a source surface (eg the sun’s peak emission is in the UV range where the absorptivity of aluminum and white surfaces is very low) while the emissivity of a surface is only a measured property of its own temperature.
    The other thing to note is that the Stefan-Boltzmann equation only applies to surfaces in a vacuum (based on results of test work by Stefan and Fourier) and was later found by Boltzmann could be derived (with assumptions of surfaces, blackbody and no other absorbing material ie presumed vacuum) from the Planck spectral distribution.
    A gas is not a surface and the normal S-B equation does not apply. Hoyt Hottel determined from measurements the use of path lengths, and emissivities to give a mathematical construct to allow calculation of heat transfer from combustion gases. This gives useful information for radiation heat flux when there is a large temperature difference (eg a flame temperature of 1500C and a surface temperature of 500C) When temperatures are low (less than 50C) radiation is less important than convection.

  35. Graeme No.3 says:

    Looking at the GISS figures recently I was struck by the difference in “Global Temperature” in 1878 and 2012 of 0.39℃. The whole series seems to have been “adjusted” to cram as much warming into the period from 1964 onwards. 1964 being a bottom year for a cooling cycle and supposedly the same temperature as 1850, so we are to believe we are in a warming trend with zero trend.
    The warming cycle from 1850-1878 undoubted occurred as reports of fast melting of glaciers in Europe attest. The cooling to 1905 looks OK, whether as severe as claimed looks doubtful but there was glacial advances in Iceland and Canada. The warming of 1905 -1944 looks OK. More melting of glaciers, Iceland warmed enough for them to resume growing barley and oats after a 400 year gap. Many would I suspect find 1944 a bit late as the warming peak and 1964 rather early as the bottom of the cool cycle, but it does have the advantage of making the rise in CO2 from 1964 look as if it doing something, they make something like a hockey stick out of the data.
    But given that in 1981 it was stated that 1980 was only 0.15℃ cooler than 1940, and in the meantime it has jumped to 0.09℃ warmer, the temperature gain from 1944 to 2012 looks merely fiddled. Interesting that adjusting it to 0.09℃ rise corresponds with recent estimates of the ocean temperature over the last 55 years of 0.09℃. It seems that the solar maximum in the 1980’s did little to raise the temperature. Could the rise in CO2 since 1960 have cooled the Earth almost as much as the active sun could warm it? Don’t tell the IPCC or they will start a new crusade beause CO2 is cooling the climate.

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