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Greenhouse warming 100 times greater than waste heat

What the science says...

Select a level... Basic Intermediate

Greenhouse warming is adding 100 times more heat to the climate than waste heat.

Climate Myth...

It's waste heat

"Global warming is mostly due to heat production by human industry since the 1800s, from nuclear power and fossil fuels, better termed hydrocarbons, – coal, oil, natural gas. Greenhouse gases such as carbon dioxide (CO2 play a minor role even though they are widely claimed the cause." (Morton Skorodin)

At a glance

There are various kinds of climate science deniers out there, but one grouping can usefully be classified under the acronym ABCD - Anything But Carbon Dioxide. These people appear to accept the climate is heating up. Flailing around to try and identify something other than CO2 causing the heating, they will seize upon all sorts of candidate causes. This is one of them. There are many others.

All the energy we use dissipates into the environment post-use, be it a driftwood fire on the beach or the heart of a busy metropolis, on the go 24-7. So it should come as no surprise that 'waste' heat does have a role - a minor one - in heating the planet. Humans have always been fond of fire since they learned to ignite things and there's nothing better than sitting round a blaze of a night with a few friends. No need to feel guilty about that. It's harmless in the overall scheme of things.

Waste heat is of course a much studied subject. After all, more sophisticated heating systems, compared to that fire on the beach, are energy-intensive and that translates as expensive. Ways to minimise heat loss and thereby improve efficiency form an active research topic. In that sense, a number of studies have looked at the bigger picture: just how much waste heat is there?

Unsurprisingly, cities, where huge numbers of people work, rest and play, are megacentres of heat wastage. The term, 'Urban Heat Island', acknowledges this. But the planet is a big old place and cities occupy relatively small parts of it. To find the warming contribution of waste heat, you need to have two figures: the total energy lost and the surface area of the planet. Doing the maths you can then derive the amount, expressed in watts per square metre. You can then compare it to other heat sources.

All studies of waste heat have arrived at a similar conclusion. There's a lot of waste heat over cities but the total, global amount, expressed as watts per square metre of the planetary surface, is a tiny fraction of the heating caused by the greenhouse gases. So while it's highly desirable to find better efficiencies in energy use and conservation, thereby saving money, when it comes to temperature it's greenhouse gas emissions we have to hold firmly in our focus. ABCD indeed. Next.

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!

Further details

Heat is released to the atmosphere as a result of human activities, many of which involve combustion of fuels, directly or indirectly. Sources of this 'anthropogenic heat' include industrial plants, heating of buildings, air-conditioning, vehicle exhausts and many more. In cities, anthropogenic heat typically contributes 15–50 W/m2 to the local heat balance, and several hundred W/m2 can be reached in the centres of large cities in colder climates.

This heat doesn't just disappear - it dissipates into our environment. How much does waste heat contribute to global warming? There have been several studies over the years, widely-cited examples being Flanner (2009) (if you want to read the full paper, access details are posted here), Dong et al. (2017) and Varquez et al. (2021). All have come up with similar numbers despite differences in methodology: the core message is that while waste heat is an issue and is self-evidently undesirable, its contribution to global warming is a tiny fraction of that brought about by CO2.

Flanner concluded that the contribution of waste heat to the global climate was 0.028 W/m2. That was with respect to the mid 2000s. In contrast, the contribution from human-emitted greenhouse gases at the time was 2.9 W/m2 (fig. 1). So in the mid 2000s, waste heat amounted to about 1% of the total warming, with greenhouse gases making up much of the rest. The above numbers refer to radiative forcing, the change in energy flux at the top of the atmosphere. Or putting it in plain English, the amount of heat being added to our climate.

Relative radiative forcings due to waste heat and CO2.

Fig. 1: the relative radiative forcings due to waste heat and CO2 in the mid 2000s, from the numbers presented by Flanner (2009).

Since that time, both greenhouse gases and energy use have gone up (fig. 2), so it should come as no surprise to see increases in radiative forcing in both cases. Future projections have largely been focussed on recovery of the waste heat, such as that by Firth et al. (2019). An important conclusion of theirs is that, "full recovery of the theoretical potential is found to lead to a 10–12% reduction in the combined forcing of CO2 and waste heat over this period, mainly due to a reduction in CO2 emissions."

An important point to consider here is that the warming from thermal energy production occurs when a fossil fuel undergoes combustion. Whoomph! and that's that - the energy is produced in a single pulse then dissipates away. In contrast, warming from the emitted CO2 continues for the lifetime of CO2 in the atmosphere - potentially thousands of years (Zhang & Caldeira 2015). Zhang and Caldeira showed that "the energy released from the combustion of fossil fuels is now about 1.71% of the radiative forcing from CO2 that has accumulated in the atmosphere as a consequence of historical fossil fuel combustion." Again a small fraction of the CO2 radiative forcing, and emphasising the issue of the cumulative build-up of CO2 due to its relatively long atmospheric residence time.

Total energy use on Earth.

Fig. 2: total energy use on Earth, 1800-2023.

To conclude, greenhouse warming is currently adding some 60-100 times more heat to our climate than waste heat. That's not to say we should not be bothered about waste heat though, There are many sound reasons, including economic, for reducing heat wastage. It makes no sense at all to tolerate systems that for various reasons are grossly inefficient. But that needs to be considered as a separate entity from the huge problem of human CO2 emissions.

Last updated on 7 January 2024 by John Mason. View Archives

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Comments 126 to 150 out of 153:

  1. jmorpuss I see a lot of effort to move energy minimizing losses. And clearly I do not by the idea that the less energy is absorbed the more the air will warm. I belive in energy conservation, call me crazy.
  2. "Your link to 2011 world energy outlook states in the second line that it's about the energy market, so I prosume it only takes into account metered power or power that is taken from the grid. " Ah no. It is about the energy generated and measured at source. Much easier to measure.
  3. This thread starts off with the assertion that GHG's warm the earth to the extent of 2.9 w/m2 compared with .031 generated by man. (according to my calculation using 2012 energy output).  Quite a straightforward calculation shows that .031 equates to raising the entire mass of the earth's atmosphere by 1/10th deg p.a. So GHG's raise it by 10 degrees p.a. - tell that to the fairies! The amount of energy dissipated by radiation from the earth's surface is a tiny fraction of that by conduction, convection (natural) and forced as the following basic physics illustrates:

    1) Long established by theory and measurement we have values for thermal conductivity of gases at STP. Typical experiment has two horizontal parallel plates too close to allow convection and a temperature gradient. The correction for the contribution from radiation is about 5%. (Physics text books)

    2) Natural convection has been well established to obey certain rules for all gases (monatomic, diatomic etc). For air, at 300 deg. K it effectively doubles the conductivity values established in 1 above.

    3) Forced convection - the situation at the earth's surface - is where I make an informed guess. My old car boils if left idling for ten minutes with the fan off, at 30 mph, where the engine is dissipating at least ten times the energy, it is as cool as a cucumber. Perhaps the average wind at the earth's surface is less, but to bend over as far backwards as possible in favour of the GG fanatics, lets say it multiplies cooling by a factor of five rather than ten.

    4) Of this small proportion an even smaller proportion of the spectrum will find molecules with which to resonate. Whether the excited molecule simply exchanges energy with the surface or suffers a collision transfering to kinetic energy is neither here nor there, because the upshot is it will make an immaterial difference to the total energy transfer.

    5) Contrast this with the situation at the edge of space where very hot molecules become ionised and each and every single one of them that moves then becomes a e/m radiator losing its kinetic energy in the process. This is where the business of transforming kinetic into radiant energy takes place, it is the lower world's ultimate heat sink.

     We inhabit the coolant of an enclosed air-cooled machine, the heat source, the sun (and man), the heat sinks comprise moving media - the oceans - the poles and the unlit side of the earth. But, there must be another sink which provides a route out by radiation. Just as the sun's surface temperature determines the solar spectrum, so does the surface skin - the upper atmosphere ionised shell- of the atmosphere. 


    [TD]  At least you are on some other thread than the one you started on.  But the bulk of this comment by you belongs not on the waste heat thread, but on the other thread that Tom Curtis pointed you to earlier.  Before you comment on that other thread, you really, really should read the orginal post there.

  4. Old sage, as others have indicated, you are working from an absurdly incorrect understanding of what greenhouse house assets. It has nothing whatsoever to do with conductive properties, and everything to do with radiative properties of the gas. These are lab determined, first observed by Arrhenius. Downwelling radiation is also something that you measure (so you can check observation against theory). Your arguments are a nonsense strawman - a argument about something that science does not claim. You need to read up on what radiative physics actually asserts and how it is experimentally verified before trying to continue a conversation. I would recommend this excellent series for the text book background to the subject.

  5. old sage - " informed guess"

    Why guess? Trenbert et al 2009 is a fine place to start, to look at actual (measured) numbers for convection, evaporation, radiation, etc.:

    Trenberth et al 2009 Energy Budget

    I consider this particular diagram a basic starting point for energy balance discussions, regardless of whether or not you agree with all the numbers listed. 

    Thermals (convection) account for some 17 W/m2 leaving the Earths surface, evaporation/transpiration another 80, and IR radiation the majority at ~396 W/m2. The references on that paper (as well as similar works) lead directly to descriptions of how these quantities were measured. 

    That heating of the near-surface atmosphere results in an IR emission of ~333 W/m2 back to the Earth (again, a measured quantity). Absorption of IR at GHG frequencies occurs within a few 10's of meters at sea level - the effective radiating altitude (high up, much cooler) where emitted IR can escape to space is where GHG concentrations drop to a density allowing that escape. 

    Convection indeed has an important role - radiative transfer isn't terribly effective in comparison to convection/evaporation, and the convection in the troposphere allows much more of that near-surface energy to reach effective radiating altitudes - without convection the GHG would make the Earth much much warmer. 

    On the other hand, without GHGs and near-surface atmospheric radiation, all of the IR radiated from the surface would travel directly to space - 240 W/m2 from the surface, rather than the atmosphere as a whole. And that would correspond to a radiating suface temperature of about -18C, some 33C cooler than present. 

    "...tell that to the fairies!" - Looking magnitudes, 2.9 W/m2 imbalance from atmospheric change is roughly 100x the 0.031 W/m2 from our energy release. Waste heat is therefore a near-trivial influence on current warming. I would suggest you listen to the measurements rather than your intuition. And note that Arguments from Incredulity are a logical fallacy; the actual data disagrees with your statements. 


    In short: Your estimates are wrong, the numbers show otherwise. Waste heat is a trivial influence with respect to GHG changes, convection is more than 15x smaller than radiation in terms of energy, GHGs don't need to be ionized plasma to radiate, and there is no missing energy sink. There is, in fact, absolutely nothing correct about your last post - all of your (qualitative, I'll note, not numeric) claims are contradicted by the data. I would suggest doing some reading before making additional claims (as you have been) that all of the science is wrong. 

  6. old sage.

    Your argued position here appears to rest on the method used to measure themal conductivity in fluids as described in your physics text book. Radation and convection effects are something such a method would require to reduce to insignificance because if not the measurement method would need amending to account for them.

    Thus when you say radiation is only 5% the effect of conduction, that simply demonstrates a well designed method (although 5% due to radiation is actually pretty rubbish, to be honest).

    But you are taking this 5% figure and asserting it to be some universal ratio of the relative importance of conduction and radiation. Such a use is nonsensical.

    I would suggest you read the rest of that physics text book. This will allow you to make some very basic calculations for the size of radiative energy fluxes through the Earth's atmosphere and you will quickly discover that the 5% figure is entirely inappropriate.

  7. Very interesting chart that KR, it rewrites the laws of physics replacing that of conservation of energy with conservation of radiation and as for the kinetic theory of gases, forget it.  Hardly a joule from conduction and not an erg from the radiative shell surrounding earth.

    Hey ho.


    [TD] Put your comments about the energy budget somewhere more appropriate, such as the post by Trenberth.  Put your comments about the basics of the greenhouse gas mechanism somewhere more appropriate such as the post Tom Curtis pointed you to.  In all cases, you really need to read the original posts before commenting.

  8. Old Sage, I have replied to your comment on an appropriate thread. If you want to continue this conversation, do so over there, not here.

  9. Old Sage:

    The Science of Doom is a "go to" website for anyone seeking to better understand the mathmetics of climate science. The site is devoted to evaluating and explaining climate science in a very structured manner. It has a 13-part series about Atmsophereic Radiation which you should carefully study. 

  10. A comment on convection and transfer of heat...

    Where there is a hot spot or heat source on the surface (from waste heat, for example) convection is a crucial way that excess heat is carried away and up into the atmosphere. As I understand it, convection is extremely effective; and it transfers heat much faster than radiation in the atmosphere -- as long as there is an energy imbalance to drive the convection.

    Convection, however, is capped; it cannot carry heat away out into space. So it will tend to bring the atmosphere into a state of convective equilibrium. This equilibrium is called the "lapse rate". This is the temperature profile of the atmosphere where there is no transfer of heat energy as a "packet" of air moves up or down. The temperature change of the atmosphere at different altitudes matches the temperature change from expansion or compression with the pressure change (and condensation, in the case of a moist atmosphere). An "unstable" atmosphere is one where convection will restore the equilibrium, and this cannot last for long before convection restores the conventional lapse rate. This is caused by heat at the surface or low altitude.

    You can also get cases where air at higher altitude is warmer than you would expect from the lapse rate; but this case is called “stable”, because convection doesn’t move hot air downwards. This condition of the atmosphere is broken up usually by winds and horizontal circulations, or else by loss of heat from radiation of the hot air – a much slower process than convection.

    This doesn’t support Old Sage’s claims; the actual energy flows from convection are pretty small by comparison with radiation. Convection is fast, but as with any spontaneous thermal process, it works to remove the conditions which drive it. Radiation works more slowly, but this energy flow is not capped at the top of the atmosphere, so there’s a continuous ongoing flow of radiation out into space.

    The lapse rate in the atmosphere – the fall in temperature with altitude – is a crucial part of how the greenhouse effect works. The capacity of the atmosphere to absorb and emit IR radiation means that a much of the Earth’s emissions to space comes from emissions high in the atmosphere; where it is cooler than the surface. In order to shed the heat Earth absorbs from the Sun, temperatures overall must be that much hotter to get a balancing emission of energy back to space.

    Summary sentence: the efficiency and speed of convection maintains the atmosphere close to conditions of a convective equilibrium – in which the major energy flows by far are from radiation.

  11. I haven't replied to my various critics here before because I despair of the disconnect between the various scientific principles others have cited and the context in which they haver been applied. What makes Physics a difficult subject for some is that what is true under some conditions can be just the opposite under others.

    For instance a factor of 100 is argued above as the difference between waste heat and GHG forcing so the former is therefore irrelevant to global warming. Given that waste heat is readily shown to equate to warming the entire mass of the atmosphere by some 1/10 deg p.a., the two numbers must be describing totally different things. Waste heat is almost entirely applied to the kinetic heat of atmospheric gases and it is trapped until transported by mass transfer down prevailing winds to cooler regions. It cannot get out by radiation. If GHG forcing is supposed to measure the rate at which GHG's are heating the atmosphere, then I'd like to know where it is going because at 100 times waste heat it is unsupportable. Gases under the conditions applying to the vast bulk of the atmosphere do not convert their kinetic energy into e-m radiation.

    The energy balance of the earth's atmosphere has been exactly zero to all intents and purposes for thousands of millions of years. The perturbation represented by waste heat applies to scales in balance by natural processes and it is large incomparison with zero. It is moreover, bang on quantum for the scale of consequences observed. 

    The emphasis on CO2 by the IPCC is tantamount to saying the carbon cycle governs Earth's temperature. In that case, how did it get to support life in the first place?  Earth has an extremely robust set of physical properties which have returned equilibrium after cataclysmic events. It could even be argued that the burning of fossil fuels by increasing CO2 and reducing O2 would cause more sunlight to be sequestered by photosynthesis according to proven chemistry principles thus tending to lower energy available for heating - given we had not swapped vegetation for concrete.

    We might understand the warming better if we took account of the physical stabilisers. Stefan and T^4 applies to the huge inertia of the global surface. Any perturbation due to an atmospheric source - eg CO2 - of tiny inertia would have to be seriously amplified before any correction kicked in from Stefan.

    An exception is water which vapourises relatively easily. Far and away the most responsive physical property to a warmer globe is more vapour. That means more condensate higher up absorbing and re-radiating near the TOA so reducing takeup of solar energy.

    Another property is the vigour of the atmosphere related to which will be activity in the plasma which floats upon it and in the earth's field. That will act as a generator as will violent electrical storms and they emit energy in the visible spectrum as well as longer. More than half of that will escape earth due to geometry.

    So the CO2 argument is a simplification which buys time for those who worship the totem of economic growth- mostly from population increase - the real source of mans climate impact. It is far more multi-faceted than that but then the drive to claw back energy from sun and wind does indicate that despite the apparent lack of economic justification someone has worked it out.

  12. Old Sage,

    You need to go back to High School. In my High School AP Chemistry class, the students learn that heat is heat.  It does not matter if it comes from the sun or from waste heat, it is the same once it gets into the atmosphere.  When you say absurd things like: 

    "Waste heat is almost entirely applied to the kinetic heat of atmospheric gases and it is trapped until transported by mass transfer down prevailing winds to cooler regions. It cannot get out by radiation."


    "Gases under the conditions applying to the vast bulk of the atmosphere do not convert their kinetic energy into e-m radiation."

    everyone else  knows that you have no idea what you are talking about.  Please provide scientific references for your wild claims.  I note that you have provided no references, only unsupported assertions of fact.  In fact, like all the rest of matter in the universe, the atmosphere radiates black body radiation.  The energy from waste heat is radiated into space like the much greater amount of energy that is received from the sun.  What possible mechanism could differentiate the heat from the sun and the heat from waste heat?  Heat is heat.

    Keep in mind that this is a scientific board.  Other people know what they are talking about even if you do not.   

  13. "Given that waste heat is readily shown to equate to warming the entire mass of the atmosphere by some 1/10 deg p.a."

    No it doesnt. Perhaps if you show us your working, it might help pinpoint your misunderstanding but you seem to be missing the very basics of physical understanding here. You cant just turn bits of physics off (like Planck's law) and try an compartmentalize things by looking at only part of the processes at work.

  14. And just a more realistic calculation:

    With average surface temperature at 288K you have surface heat flux of 390W/m2 (see Keihl and Trenberth for measurement details - but matches Stefan-Boltzmann law pretty well - try it yourself). Increase heatflux by 0.028W/m2 and you get a temperature increase from S-B law of 0.0052, with emissivity of 1. A very long way from 1/10 degree.

  15. Michael Sweet - damnit man get your graduate level books on the kinetic theory of gases out before you get hysterical about heat transfer mechanisms you clearly do not understand. At the simplest level taking 98% of the atmosphere - N2 and O2 - is transparent to visible and i/r radiation- so poor absorbers make poor emitters at school book level. Check out the values of the virial coefficients and make an effort to understand them. Atmospheric gases pass heat around by kinetic movement, they need to get up to thousands of degrees - or break down in vacuo under high voltage - before they radiate.

    Scad:  weight of atmosphere = 5.1x10^18 kgs approx  1.7x10^20 mols

    Oil production 3.1x10^10 b/yr each giving 6.1x10^9 joules = 4.5x10^19 cals

    Specific heat of gases in atmosphere all about 6 cals/mol/deg. That equates to 4.4x10^-2 degrees rise in T. Then you must add in gas, nuclear, coal - I've done this but cannot lay hands on figures just now but it just about doubles the effect. That is using the measured and recorded outputs for sale (2012) - how inefficient are these industries so what extra would you add?


    Climate models are bedevilled by large numbers which in the absence of man's mining of surplus solar energy from millenia past, not to mention that in the nuclear atom from creation, balance.   It is a strange coincidence that this extra impost together with other impacts of man's industry is about right as explanation.




  16. Does artifact waste heat have special properties which make it selectively resistant to entropy via radiation at the top of the atmosphere? If so, the person who knows how this works should definitely keep clam until they've filed patent applications. :-)

  17. Old Sage @140, argues correctly that N2 and O2 are transparent to IR and visible light (mostly), and that therefore they are poor emitters or IR radiation.  He does not follow through and note that CO2 and H2O are strong absorbers of IR radiation, and therefore strong emitters of IR radiation if the wavelength of absorption lies within the blackbody spectrum at the temperatures of at which they absorb.  Here is the main absorption band of CO2 with respect to the black body curve of bodies at typical Earth surface temperatures:

    The CO2 absorption band at about a wavenumber of 700 cm^-1 clearly lies near the center of the blackbody spectrum, and will radiate strongly without need of ionization at normal Earth surface temperatures.  Additional absorption bands due to H2O (0-600; 1300-1600), O3 (1050) and CH4 (1300) are also visible, and will also radiate strongly at normal Earth surface temperatures.  Old Sage proves his sagacity by simply ignoring the implications of the argument he is happy to deploy whenever they are inconvenient to his position.

    Of course, the above graph only comes from a model.  We need an empirical test.  One possible test is that if we look up at wavelengths in the IR spectrum in which CO2 is expected to radiate, we will see a strong IR signal.  Conversely, were no constituent of the atmosphere is expected to radiate, we expect to see no such signal:


    The graph shows the IR spectrum at the same location, with one image (a) looking down from altitude, while the other (b) looks up from the surface.

    This has all been explained to Old Sage before, but confident in his own wisdom, he pays attention to neither the well worked out and confirmed theories of physicists; nor to the implications of the observations themselves. 

  18. I'd like to know why old "sage" thinks Planck's Law doesnt apply to gases? And where all that radiation cames from that satellites measure if he believes it is heat is somehow trapped in the atmosphere?

  19. And a further note - in addition to an atmosphere that doesnt radiate,  old sage's calculation requires  that somehow waste heat cant warm the ocean (the upper 2.5m having same heat capacity as entire atmosphere).

  20. Ols "Sage" has yet to supply a single reference supporting his absurd claims about heat in the atmosphere.   He is sloganeering and should be required to support his position to continue posting.  He is completely ignorant about heat transfer and he refuses to read the informed posts that Tom has, again, made for him.

  21. Old Sage wrote "I am puzzled by the fact that I am not aware of anyone who says that 250ppm or 450 ppm of CO2 is the cause of warming has put it in the context of the concentration required to render the atmosphere totally opaque."

    AFAICS, you appear to be labouring over a fundamental misunderstanding of the mechanism underpinning the enhanced greenhouse effect.  The absoption of IR emitted from the surface by CO2 is a red-herring; what matters is the temperature of the layer in the atmosphere from which IR can escape without being absorbed by the CO2.  See this RealClimate article by Spencer Weart and Raymond Pierrehumbert.

    "The only reason I can see for pinning warming on CO2 is that it is increasing and is a useful parameter for sticking in a model, well"

    Well perhaps you should read up on the basic mechanism of the EGHE before making pronouncements.  The basic mechansim was set out quite clearly by Gilbert Plass in the 1950s.  You are unlikely to convince anybody with your theories until you can show that you have at least read up on the basics of the mainstream scientific understanding of climate change.


    [JH] I deleteed Old Sage's most recent post because it was sloganeering. I am letting this comment stand because it accurately quotes statements made by Old Sage in his post. Other repsonses to Old Sage's post will be deleted.

  22. Old Sage:

    Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

  23. I'll try and be more specific. If you take a textbook example and say ask how much will body increase in temperature if you add x extra joules to it, then looking at heat capacity is certainly the way to go. But that is not the relevant equation, because you are ignoring energy transfer out of the system. The text book is fine but you have to read all the chapters. You appear to have read the chapters on conductive heat transfer and missed the one on radiative transfer.


    Principles of Heat Transfer, Kreith (1965) or

    Fundamentals of Heat and Mass Transfer, Incropera and DeWitt (2007) for more modern.

    Or if you are more my age, then

    Heat and Mass Transfer, by Eckert and Drake (1959)

  24. Old Sage: Your two most recent posts have been deleted for violating three prohibitions of the SkS Comment Policy, i.e., moderation complaint, sloganeering, and excessive repitition.

    If you continue to violate the SKS Comment Policy, you will forfeit your ability to post comments on SkS articles. 

  25. Despite the (as John Hart notes) excessive repetition in Old Sage's post that resulted in its being deleted, he does raise the interesting question of how much energy escapes to space due to lighting.  I am unfamiliar with the literature on lightning, so the following estimate should be taken with a grain of salt.  Never-the-less, the frequency of lightning strikes has been well surveyed (Christian et al, (2003) "Global distribution and frequency of lightning as observed from space by the optical transient detector"), with an upper limit of 50 flashes per second.  That is significantly below traditional estimates if 100 flashes per second because (as it turns out) lightning is infrequent over oceans relative to its frequency over land, leading to ground based estimates being biased.  The average energy release per lightning strike is 4 x 10^8 Joules.  I believe much of that release is in terms of electrical transfer, and in the ionization of the air, rather than actual electromagnetic radiation.  Further, most of the electromagnetic radiation will be absorbed on the Earth's surface or in the atmosphere.  Never-the-less, I will use that value.

    With the two values combined, it is easy to determine that the total global energy release by lightning averages 2 x 10^10 Joules per second, or 3.9 x 10^-5 W/m^2 averaged over the entire global surface.  That represents just 0.14% of global waste heat from human use of energy, and hardly counts as a significant factor in the global energy balance.

    Briefly, Old Sage also referred to radiation at very low frequency and ultralow frequency wave lengths.  That radiation (except for that from lightning) is thermal radiation, and included in the energy calculations of the black body radiation of the Earth already.    

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