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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 76 to 100 out of 205:

  1. mullum#74: Try this thought experiment. The topic of this thread is waste heat. Your glass greenhouses are of no relevance. But you're already in full-fledged GHE/AGW denial mode, consistent with some posts under the same name on other blogs. SkS runs a bit differently than those blogs: I suggest a thorough review of the various policies here, including the Newcomer's Guide and especially the Comments Policy, where you will note some language advising against using all caps. Use the Search function to find a thread of interest and pose questions relevant to the thread. There are nearly 170 skeptic 'arguments' addressed in considerable detail. Most important of all, you won't get away with denying the evidence, as in: "With no accumulating energy gain, there is nothing to drive the hurricanes, floods, droughts, heatwaves, snow dumps, melting ice etc etc". A general principle of science is this -- if you have a premise (in your case, there's no climate change) that conflicts with multiple lines of evidence, your premise is probably incorrect. Stick to the science; avoid forming opinions based on speculation about pots of water, balloons, sheets of plywood in the sun and glass greenhouses.
  2. mullumhillbilly @74, your experimental design would not work because: (a) you have not controlled for back radiation; and (b) the CO2 atmosphere in your experiment would have approximately the same temperature as the surface, thus precluding any greenhouse effect. In contrast, in nature there is no back radiation from space, and the CO2 in the upper troposphere (from which most IR radiation absorbed by CO2 is reradiated to space is much colder than the surface of the Earth because of the adiabatic lapse rate. These two factors make it difficult (though not impossible) to model the greenhouse effect in a simple small scale experiment; a fact that has lead many people (including the Myth Busters) to develop essentially flawed experiments. Despite that your thought experiment is an interesting approach. However, you cannot apply it to the macroscale as you do. The systems you describe "equilibriate" when average energy in matches average energy out. However, the energy in at night consists of the cosmic microwave background radiation (<< 1 W/m^2), the geothermal heat (0.1 W/m^2), and industrial waste heat (0.03 W/m^2) plus a few very minor terms from meteor impacts, cosmic rays and the like. That means to reach equilibrium the temperature would need to drop to less than 65 degrees K (less than - 208 degrees C). The lowest temperatures on Earth are found in the Antarctic in winter, when it sometimes drops to -100 degrees C, but even there, equilibrium night time temperature is never reached. Six months of darkness is not enough to reach an equilibrium night time temperature on the surface of the Earth. Only a minority of the thermal inertia that means equilibrium night time (or day time) temperatures are never reached on Earth are a consequence of the greenhouse effect. But it certainly means heat from the greenhouse effect can accumulate from day to day, and year to year.
  3. Muon@ 76. Yes I am new to posting on this site, and I assure you I'm not a reincarnation of any previous posters. I am wading through the long "waste heat" thread you referred to earlier; I didnt know it existed when I first posted here... bit confusing I think having two threads on the same topic. As to sticking to the science, that's what I am attempting. This site is, after all, called "Skeptical Science", so I think its appropriate to ask questions, no? Sorry about the caps, I haven't discovered how to use bold or italics here, and didnt think it was even possible except I see that Tom in 77 has just done so. I'm happy to take the glasshouse questions elsewhere if you can suggest the appropriate place. Tom@77. I did say "in equilibrium with their surroundings", but didnt mean that to include the entire galaxy :-). Both glasshouses start cooling when the sun's forcing stops. I accepted that the CO2 enriched glasshouse (Gh.8x) cools more slowly than the control (Gh.1x). But sometime before dawn the temperature and heat content of both glasshouses is the same, ie they both get to equilibrium with their (local) surroundings. Put an open-top thermos flask with warm water and a cup of same volume of warm water into a fridge and wait. The thermos will stay warm for longer but it won't be long before they are both the same temperature. So, the Gh.8x can only slow down the cooling briefly, but eventually comes into equilibrium with the ambient fridge air. Would you agree? I'm not questioning the existence of a greenhouse effect per se, but I am questioning whether a short period of less-than-normal overnight cooling is in fact "climate change", notwithstanding that "average" temps appear to be higher. I'm not sure why the experiment is invalid due to size alone, but let's assume that the Gh's are at least tall enough to intercept >99% of the intial LWR emitted from the surface (100m ?). The delayed outward radiation is real, but eventually the retained energy makes its way to the Gh walls/ceiling, and is transferred to outside the system. In the real world, the energy makes its way to TOA whether via convection or radiation) and transferred to outside the system. "Climate change" (as opposed to simply increase in average temperature readings over time) requires that some of that energy stays in the system. Can you point me to anywhere that empirically demonstrates or explains why it takes more than a few hours on average, for the retained energy to make its way to TOA and get lost from the system?
  4. mullumhillbilly - The disproportionate amount of energy retained by GHG emissions versus combustion is because the GHG's retain solar energy (fusion), not just release a bit of chemical energy (combustion). By comparison to any amount of coal burnt, the sun is an essentially limitless energy input. A gift that just keeps on giving, unfortunately... I will note that Gedankenexperiments regarding greenhouses, glass plates, etc., have led a number of commenters astray - glass greenhouse analogies really don't capture the details of radiative physics and energy flows.
  5. KR@70 ...keeps on giving... What's till puzzling me is Flanner 2009 magnifying the original fire *100 every year with GHGs, where my calcs above (noting the corrected arithemetic to convert W->J) suggest magnifying the fires heat by just 1.5 with GHGs, and that only after CO2 has doubled (ie the original heat reproduced every 0.66 yrs). I suspect (not being able to access the original) that Flanners figure probaly includes the whole of GHG effect, not just the marginal AGW additions that I used. Either way, this is one amazing "eternal flame". So analogy good, Gedankenexperiment bad ? OK so you don't like the glasshouse, or the fridge. Well, could you perhaps address the questions anyway ? Maybe they are already dealt with elsewhere on this site, but its rather labyrinthine, and too voluminous to wade through all the comments (which dont get included in the search engine), and I havent found an answer with the search terms I used. So apologies if you feel your time is being wasted, but I am genuinely interested in finding an answer, not arguing from an entrenched position. Rather than two glasshouses, can you imagine two identical planets Earth.2x and Earth.1x ? On Earth.2x, the atmosphere with doubled load of GHG will slow down the rate of night cooling (heat loss) compared to that on Earth.1x. However in the absence of new forcings (the sun), the amount of heat energy held in Earth.2x atmosphere and oceans will eventually equal that on Earth 1.x. , and that would happen well above zero energy point on both planets. Would you agree with that in principle? If we can agree on that, the key question would be "how long is eventually ?" If its less than 12 hours, it seems to me that, nightwarming and rises in "average" temperature notwithstanding, there is nothing that constitutes "climate change", no residual energy to drive the cyclones, floods and ice melt. So can you point me to anywhere that empirically demonstrates or explains why it takes more than a few hours on average, for the obstructed/trapped/retained energy to make its way to TOA and get lost from the system?
  6. mullumhillbilly Thought experiments and analogies both have their issues - they are fine as long as the points being discussed actually map to the system under discussion, but have a tendency for irrelevant aspects of the analogy to be taken as part of the mapped system. The core of what happens with the greenhouse effect is directly tied to conservation of energy - the amount of energy entering a system (a dynamic system like the Earth climate) must equal the amount leaving the system, or the amount of energy in the system will change. Now, you can look at the Earth as a simple, zero degree system - increases in GHG's effectively reduce the emissivity (amount of energy the Earth radiates to space at any particular temperature), which means to match incoming solar energy the Earth must warm to a higher temperature before matching that with outgoing energy. In more detail, increasing GHG's raise the level in the atmosphere where infrared radiation can emit to space - and given the lapse rate of the atmosphere, those are colder regions, meaning again less energy going to space, and an imbalance between incoming/outgoing. The Earth warms, the entire atmosphere warms, and then that level where radiation can escape is warm enough to again balance the equations. It's not a matter of "energy taking more hours to leave", it's a matter of how fast energy can leave, based upon the physical radiative characteristics of the Earth. In terms of simple analogies, I like to think of the Earth as a bucket in a waterfall. Energy comes in, overflows the edges, and goes out - increased GHG's raise the side of the bucket, the water/energy level must get higher to flow out at the rate it's coming in. (Moderators - previous comment was in error, due to my fumblefingeredly hitting the wrong button; could you delete that?)
  7. KR@81 >It's not a matter of "energy taking more hours to leave", it's a matter of how fast energy can leave. So "fast" has nothing to do with time? I agree there is near-ground early-evening warming, and I think I understand the essentials of the emissivity picture, S-B & T^4 etc, but the clock is still a factor. If the heat energy is not accumulating daily (on average at the rate of 100:1 GHG energy:combustion energy if you agree with Flanner 2009), then climate sensitivity is not as high as you think it is. Raising the edge of the bucket in a waterfall is not a good analogy because you are talking about continuous flow, whereas GHG only operate to trap (delay) the flow when the sun is not shining.

    [DB] "whereas GHG only operate to trap (delay) the flow when the sun is not shining"

    You are considerably in error on this; GHG's do their thing 24/7/365, rain/shine/by dark of night.

  8. mullumhillbilly#82: "GHG only operate to trap (delay) the flow when the sun is not shining. " Really? Doesn't the warming surface radiate IR during the daytime? If not, why not? How do the GHG molecules know what time of day it is?
  9. mullumhillbilly - The only way for energy to leave the Earth climate is as thermal radiation. All else is just re-arrangements of the energy within the climate. Thermal radiation leaves any object at a rate determined by (a) temperature, and (b) the ability of the surface to radiate at that temperature. Please see this Thermal Radiation wiki for an overview. Without GHG's, the surface of the Earth radiating at an emissivity of 0.98 (98% of theoretic max efficiency, as dirt and water are very effective emitters of IR) would be able to match incoming energy at a temperature of ~255K, or -18C. That would be cold. GHG's absorb IR, re-radiate a great deal back to the surface, and most importantly, as GHG concentrations increase, the effective level in the atmosphere where IR can escape is higher and (due to the lapse rate) colder. Therefore less IR escapes at GHG frequencies at any particular temperature. In order to radiate as much energy as is incoming, the Earth has to be warmer. See the following: The smooth curve shows what a 'blackbody' could emit. The notches are where GHG's reduce radiation at any particular temperature. In order to radiate the same energy as the blackbody, the integrated area of the jagged curve must match the area of the smooth one, and hence the entire curve must be higher - the temperature of the emitting body (in this case the Earth) must be higher to scale it up. In this case, as observed, about 15C. Then outgoing matches incoming energy. --- If this is not comprehensible, I strongly suggest doing some reading on the basics of the radiative greenhouse effect. There's tons of information out there for you.
  10. DB82, muonc83, OK that was an oversimplification, but my essential point stands I think. GHG are working around the clock but daytime incoming radiation far outweighs any interception of surface FIR, so most of the GHG warming of the atmosphere happens at night. On the bright side of the moon surface temps are +100C, dark side -150C. Are you telling me GHGs make the planet warmer during daytime?

    [DB] "Are you telling me GHGs make the planet warmer during daytime?"

    Think about what you are implying (that molecules somehow "know" what the time of day is).

    GHG molecules do their thing 24/7/365.

    Like the Terminator, they just...don't...stop...

  11. Consider putting a thermometer in a vacuum in the shade on a sunny day. Do you expect the reading to plummet to sub-zero? Consider doing the same experiment on the moon. Look at the actual measurement of DLR (eg here) and note that DLR strongest in day as you would expect. Your daytime warmth is from both the sun directly and DLR.
  12. mullumhillbilly @85, it is true that the diurnal (day/night) difference between warming due to insolation is far greater than the diurnal difference in warming due to GHG. But the GHG cause more warming during the day than during the night. The primary reason the earth has such a small diurnal range compared the the moon is the presence of a liquid ocean which requires the storage or release of very large amounts of energy to heat or cool, thus keeping temperatures relatively constant. The atmosphere, particularly when humid, has a similar but smaller effect. That is quite distinct from the GHE.
  13. KR84, Yes GHGs_101 is quite comprehensible thank you, but this really doesn't address the question of time. So less FIR (LWR) escapes to begin with at night, but the surface cools rapidly as the night goes on (frost) and the IR drops well before dawn. Diurnal variation of IR is not a new idea. I'm saying time is important, and you glossed over that. Climate sensitivity is very much dependent on how much of the trapped/delayed IR-sourced energy makes its way to TOA by dawn (incl by convection), and thence is lost to space.
  14. scaddenp@86 ?? DLR is highest at night in your diagrams, except for a couple of early afternoon peaks when presumably some clouds passed over. Thermometer in the shade. If it truly was totally insulated from any external energy, of course it would drop to zero, whether on the Moon or on Venus. What's your point?
  15. tomCurtis@87. So you are saying humidity and water vapour are NOT part of the GHE? I agree re buffering capacity of oceans, thence maritime climate cf inland deserts, and I was simply using the Moon example to illustrate the overwhelming warming effect of direct insolation vs GHGs. You say "GHGs cause more warming during the day than during the night". Presumably you mean the net effect is significant. (net being gross "trapping" minus emission back to space). Is the surface temperature record reliable enough to show this? As I understand it, most (if not all) of the demonstrated warming has been at night in higher latitudes. I don't think we have the information to say whether that night warming (eg is it based on higher minimum temps, or an integral of degree-hours?) actually reperesents retention of energy in the system. I've already suggested how higher night temps can occur without net gain of energy in a 24 hour cycle. I'm not even disputing that there may be some residual energy accumulating, but the actual amount is crucial to climate sensitivity.
  16. mullumhillbilly - A quick search on your moniker indicates that you have been posting on climate topics for a while, complete with heavy use of the term "warmist". I'm not interested in recapitulating the entire greenhouse gas theory to someone who should know it by this point. I would suggest reading through the Science of Doom greenhouse effect pages, then returning if you still have any questions. GHG's warm the climate both night and day, reducing the diurnal temperature variations by reducing the climates ability to dump heat quickly. At the moment you are giving me a very strong impression of being disingenuous, of arguing for the sake of arguing, and of raising silly objections. Just not worth my while...
  17. I am pointing out DLR is operating significantly in day time. Your timing argument makes no sense to me. At climate scale, you are looking at annual averages. You think models are based on calculations for a particular time of the day?
  18. mullumhillbilly#91: "most (if not all) of the demonstrated warming has been at night in higher latitudes" It's high time you started doing as most others here do: Substantiate your statements. By no means is all of the observed warming at night, nor is it all in the higher latitudes. You might want to look up 'arctic amplification' and 'diurnal temperature range' for some conceptual support. "suggested how higher night temps can occur without net gain of energy in a 24 hour cycle. " Your 'suggestions' don't carry much weight by themselves. Has anyone doing research in the climate sciences made a similar suggestion? If so, don't you owe that researcher the credit? Although KR kindly provided the sound basis for the greenhouse effect, that is not the topic on this thread. This thread is about waste heat. Thus far, you've shown nothing (other than your initial calculation errors) to counter the position of the original post: Waste heat is insignificant compared to greenhouse radiative forcing. If you have any evidence to the contrary, please feel free to share. If you have no evidence, continued speculation is not particularly interesting.
  19. mullumhillbilly @91 I never said anything like the claim that water vapour is not part of the greenhouse effect, and I resent your attempt to put words in my mouth. The specific heat capacity of gaseous H2O is approximately twice that of dry air. That means that if you increase the humidity, you increase the energy required to raise the temperature of air; and increase the energy in the air that needs to dissipate when cooling. That is an additional effect to the greenhouse effect of the water vapour. Let me add that your whole angle of attack here, in addition to being dreadfully uninformed, is entirely wrong headed. The rate at which the GHE warms the planet is a function of the energy difference between the planets current OLR and that required for equilibrium. If the planet is cooler, that difference is greater and the planet warms faster. Given that, and assume contrary to fact that the energy accumulated during the day was entirely dissipated at night. In that case, during the day time a planet with GHE will warm much faster than a planet without GHE. Hence, even if you could prove your core assumption, your conclusions would not follow. As it happens, your main assumption is grossly in error as I showed in 77. Your hand waving response was simply irrelevant. Given the absence of renewed insolation, the surface of the Earth would cool to less than -208 degrees K over time, but during the entire duration of that cooling, it would cool slower with a GHE than without it. You assume my argument is irrelevant because at some time (generally after 12 hours) another source of heat arrives, reversing the slowing. That reversal is, of course, the onset of daylight. It follows that if the planet with a GHE cools slower than one without until the onset of daylight, or more typically, a breeze carrying heat from nearby day lit areas, then more of the heat of the preceding day is retained each day with a GHE, contrary to your supposition. What is more, having retained more heat from the preceding day, with the GHE the the surface will also warm faster during the day so that, by the end of the day, it will have more heat to retain over night. For an argument like yours to have any merit, the surface of the Earth would need to cool to the point where it is in equilibrium with geothermal energy each night, which obviously does not happen. For anybody guided by evidence, that means it has no more credibility than geocentrism (it is that obviously wrong).
  20. KR@90, sure I've ventured to comment elsewhere, and have even supported your scientifically-sound comments where others were attempting to argue the second law fallacy. So I'm not here with an agressive agenda, and like you I don't have time to waste in simply arguing. I'm looking for answers to some simple questions that don't seem to have been adequately addressed, the time factor is one of them. And BTW, to me, a "Warmist" is someone who believes that climate sensitivity is higher than empirical evidence suggests, who abusively "denies" all skeptical questions or alternative explanations, who thinks that the peer-review system is beyond reproach, and who adamantly asserts that mitigation not adapatation is the only answer. Not pointing that at you, I appreciate that you are polite and patient, although it seems I'm still not getting a direct answer about the time factor. You say "..the climates ability to dump heat quickly", which again is noting that time is of the essence. scaddenp@92 I think I'm repeating myself. DLR is far less important during the day than at night, in relation to the planetary energy sum that drives climate. The yearly average is obviously an integral of daily balances, and climate sensitivity to CO2 arises from the net accumulation of atmospheric heat energy over time, for two atmospheres with differing CO2. That net accumulation seems to be predominantly at night, because that's when elevated CO2 "trapping" of FIR-LWR has greater releative significance. Elevated CO2 is not so important to climate warming during the day because SWR heating is by far predominant. What's your explanation for why DLR is less during daylight hours, peaks at ~midnight, then declines until dawn ? If the accumulation of energy over time is less than thought because pre-dawn energy losses are greater than thought, then climate sensitivity is lower than thought. I don't have any references to back that up just now, but then neither have I seen any empirical analysis of diurnal energy balance with differing CO2 concs. TomC@94. You said "The atmosphere, particularly when humid, has a similar but smaller effect. That is quite distinct from the GHE". OK, I guess I was nitpicking at you in the way others were doing to me, I'm sure you understand the effects of water vapour. "...entire duration of that cooling, it would cool slower with a GHE than without it." I don't doubt that, but on a timescale of a ~12 hour night, with soil and rock being pretty good insulators, the crucial thing is the LWR from exposed surfaces, no? eg Surface temps can be sub-zero C, but just a few cm into the soil it might be 10 deg warmer. Is there any LWR coming from the subsoil? Of course not. And if the amount of escaping LWR drops markedly after midnight (as scaddennp's link in 86 shows), then higher CO2 levels won't be "trapping" much extra energy at that time. So, I'm agreeing that a planet with GHE is warmer than one without; its strawman argument to suggest otherwise. What you dont seem to be addressing is my point that a rise in GHG might not cause the marked increase in GHE if overnight energy losses are greater than thought. Where is the "missing heat" ? Regarding "...equilibrium with geothermal energy" , that's nothing like what I'm saying, and another strawman. muonC@93. I offered to take these to another thread, but didnt get a suggestion. Feel free to transfer them if you like (but leave a link please so I can find it again). Waste heat.. yes I came to the conclusion (with appreciation for TomC@71 correcting my units conversion error) that, if (I.F.F.) CO2 doubling leads to 3.7W/m2 forcing, then GHG forcing energy is equal to combustion heat every 8 months (0.66 yrs, or factor 1.5x). Even that sounded too high, which is why I raised the overnight heat loss question. I'm still in a state of disbelief that GHG forcing can be 100x the combustion energy, every year, and will look into it further when time permits and I can find somewhere to acces Flanner's full paper.

    [DB] Try here. 

    The cost of 1 GRL article:  $25

    The power of Google:  priceless.

  21. Fuel + Oxygen --> Heat + Water + carbon dioxide. more combustion will bring about more production of heat and CO2. Decrease the rate of combustion, and you will decrease the amount of heat released, and reduce the rate of warming of air. The heating effect of the sun is a constant, and will always be there no matter what you do, whereas the burning of fuel is a variable. It is clearly heat which warms up the surrounding air, not CO2. Does reducing CO2 concentration decreases the amount of energy generated from bond breaking of the fuel? An analogy will be that of taking the elevator. When a single person takes a ride in the elevator, he is producing CO2 and radiating body heat via IR. This excess heat introduced to the atmosphere within the elevator is removed easily by the ventilation fan, which draws out heat at a constant rate. (Similar to heat dissipating heat out to space. Ever been in a crowded elevator? When you increase the number of occupants inside the elevator, more people equates to more radiation of body heat, and more emission of CO2,(analogous to increased combustion of fossil fuel), and the ventilation are unable to ventilate the elevator as efficiency. You can place a vat of CaOH to remove all the CO2 in the air, but the elevator will still remain hot and stuffy. Since CO2 is a byproduct of heat liberation, it should be perceived as an indicator of warming, rather than a causative agent of warming. I agree that CO2 is a GHG, but its effects are overrated. If you think that an increase in a slight percentage of atmospheric concentration of CO2 can bring about climate change (despite the doubling, it is still at around 0.3% atmospheric concentration, remaining more or less constant), then why not the idea that the small amount of AWH generated can actually be a more important factor in causing warming than CO2? And if you want to argue about greenhouse gases being responsible for drastic warming, why is everyone ignoring the presence of the 80% atmospheric concentration of nitrogen, which is also a greenhouse gas? Should 80% of a greenhouse gas be more significant than 0.3% of greenhouse gas? Compared to nitrogen, the decimal percentage increase of CO2 can be regarded as negligible. In the previous thread, people have been likening AWH to a cracker and GHG as icecreams, and their effect on weight gain. It is important to realise that what actually brings about a change is the presence of a non-constant factor. If your staple food consist of eating 2200 calories of icecream daily, without any gain in weight, and put on weight only after eating a 50calorie cracker, it is actually the cracker which causes the weight gain, as it is a deviation from the existing equilibrium. The output of the sun has been more or less constant, while man's energy consumption has been increasing steadily, and shouldn't the warming be attributed to this rise in energy consumption? Referring to another analogy on this thread, while a candle may not hit up the room fast enough, a furnace may. Man's energy consumption has grown from a "candle" into a "furnace", and it is this massive increase in energy liberation that accounts for the drastic rise in temperature of the room, which remains as a constant, not changing in its dimensions. And lastly, the example of a nuclear plant is a highly relevant and interesting one. If CO2 is responsible for warming, why does nuclear plants, which does not produce CO2, still emits waste heat that serves to heat up the surrounding air? The only way to reduce warming, is to increase energy efficiency, so that less energy is wasted for the unintentional heating of air.
  22. Donthc@96 To engage constructively here one is required to provide evidence for one's claims. Amongst many other things in your "thesis" that are without foundation the most obvious is: Nitrogen is not a greenhouse gas...try wikipedia for "greenhouse gas". (this site has a lot of work to do... it's like sweeping grains of supposition off a beach of ignorance)
  23. Donthc, the papers cited in this thread quantify waste heat and find it 100 times too small. If you want to argue that this quantity is in error you have to provide some evidence, not just an opinion. What calculations are you relying on? Nitrogen a GH gas? That's a good one. What else do you have in store? This makes no sense whatsoever: "If CO2 is responsible for warming, why does nuclear plants, which does not produce CO2, still emits waste heat that serves to heat up the surrounding air?" How could the radiative warming from GH gases prevent the waste heat from cooling towers to be dissipated? Why would these 2 processes be mutually exclusive? There is absolutely no reason, unless you have some new funky laws of physics up your sleeve.
  24. Donthc, others have commented on some of the fundamental errors in your analysis, but there was a particularly odd one which hasn't been remarked on yet; "The heating effect of the sun is a constant..." Right. Constant. Other than... variable levels of clouds blocking it, different surface albedo conditions reflecting it, changes in the intensity of the greenhouse effect, that whole 'day and night' thing, progression of the seasons, orbital variations (c.f. 'Milankovitch cycles'), the ~11 year solar cycle, other variations in solar output such as the Maunder minimum, the fact that the Sun is now about 30% 'hotter' than it was in the Earth's early history, et cetera. You could accurately say, 'the average annual heating effect of the Sun is currently showing only small variations on a multi-decadal scale'... but no, it is nothing like 'constant'.
  25. jmorpus has been disrailing the discussion of a new tool to handle clouds in climate models. His discussion has been inchoate, so until muoncounter and oneiota linked to websites expousing similar views, I did not know where jmorpuss was going, only that he was trampling the evidence in the dirt to get there. Having a better idea now, I now recognise jmorpuss' claims as a variant of the claim that global warming is caused by waste heat, hence my response here. The websites linked to by muoncounter and oneiota are very explicit. According to them, global warming is caused by heat generated by the absorption of radio waves from humanities many radio transmissions. Of course, human energy emissions as radio waves is a very small subset of total human energy usage. Therefore total power emissions as radiowaves is a very small fraction of the 0.028 W/m^2 waste heat by humans as calculated by Flanner, and hence an even smaller percent of the 2.9 W/m^2 GHG forcing as indicated in the article above. This is an insurmountable barrier to such theories.

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