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Waste heat vs greenhouse warming

Posted on 27 July 2010 by John Cook

A vigorous discussion has erupted on the waste heat page. Problem is, there's not meant to be a waste heat page! As I encounter new skeptic arguments, I add them to the to-do list and gradually (very gradually) research the peer-reviewed literature then write an explanation of what the science says, usually in order of popularity. I hadn't got around to looking into the issue of waste heat. Nevertheless, one intrepid Skeptical Science user found the empty page waiting to be populated and began a discussion there (j'accuse Doug Bostrom). So let's look at waste heat...

Firstly, what is waste heat? When humans use energy, it gives off heat. Whenever we burn fossil fuels, heat is emitted. This heat doesn't just disappear - it dissipates into our environment. How much does waste heat contribute to global warming? This has been calculated in Flanner 2009 (if you want to read the full paper, access details are posted here). Flanner contributes that the contribution of waste heat to the global climate is 0.028 W/m2. In contrast, the contribution from human greenhouse gases is 2.9 W/m2 (IPCC AR4 Section 2.1). Waste heat is about 1% of greenhouse warming.

Radiative forcing from waste heat vs anthropogenic greenhouse gas radiative forcing

What do these numbers mean? They 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. Greenhouse warming is currently adding about 100 times more heat to our climate than waste heat.

UPDATE 27 July: there is some confusion about the term 'waste heat'. Here, what I'm talking about is all the heat generated by energy use. When humans generate energy, much of it is immediately dissipated as heat. The rest is converted to electricity or energy of some sort (eg - mechanical, chemical, etc). But even this energy eventually dissipates as heat into the environment. So yes, 'waste heat' is not an ideal term. Flanner uses the term "anthropogenic heat flux".

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Comments 1 to 50 out of 429:

  1. As I've said elsewhere. If waste heat were such a significant contributor to the warming of the planet, then why didn't the far less thermally efficient factories & power stations of the 19th century generate a significant warming trend? Why did temperatures rise so "fast" during the Great Depression decade of the 1930's, yet fall slightly during the Wartime/post-war Industrial Boom decades of the late 1940's & 1950's? Why have temperatures risen faster during a period of increasing thermal efficiency (which means less waste heat generated) than in decades when thermal efficiency was much lower? It seems to me that this is one skeptic argument which doesn't even bear up to even distant scrutiny!
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  2. Im still at a lil o a loss as to some o the figures ive seen turn up here in regards to anthropological radiative forcing.... I followed the link to the ipcc page, and there in the table it has total human contributions listed as around 1.6W/m2 with error bars putting it out as far as possibly around 2.4W/m2. And ive generally seen it stated as 2W/m2. Where does the 2.9W/m2 figure come from?

    But, yeah, it should be pretty obvious we arnt going to compete with that big ole fusion furnace in the sky as far as putting energy into the climate system.
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    Response: The total radiative forcing from man-made greenhouse gases is 2.9 W/m2. But this is partly cancelled out by man-made aerosols which have a cooling effect. The net effect that humans have on climate is around 1.6 W/m2.


    Probability distribution functions (PDFs) from man-made forcings. Greenhouse gases are the dashed red curve. Aerosol forcings (direct and indirect cloud albedo) are the blue dashed curve. The total man-made forcing is the solid red curve (IPCC AR4 Figure 2.20b)

    Yes, the sun produces almost all the energy in our climate system. But if the sun's output stays the same, it contributes no radiative forcing. The sun only causes a change in global temperature if the solar output changes. Remember that the sun has actually been cooling in recent decades so the sun's net effect on climate has been a slight cooling.
  3. I originally thought that "waste heat" as it pertained to anthropogenic global warming was a blanket term to describe Sisyphean discussion of the AGW affair on the Internet. Once again, Skeptical Science sets the record straight!
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  4. Just for completeness, in case someone wonders about other factors, the contribution from another nuclear source - the decay of radioactive elements in the Earth's crust (40TW) - amounts to near 0.1 W/m2 which is much more significant than the waste heat.
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  5. And of course you have forgotten all the heat released by those volcanoes John, on land and undersea. Massive amounts of heat, stands to reason. You'd know that if you were a geologist.
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  6. David, you jumped the gun, in a manner of speaking. See John Chapman's post just above yours. Something like 1/30th of the amount in question, and of course as it's already been present all along is not really relevant, which is why it's not factored in the first place. Important to remember, the issue is "anthropogenic warming."
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  7. 0.028 W/m2 is derived by dividing the total worldwide energy consumption... 1.5 x E13 W by the total surface area of the Earth. These are at least Watts we can be sure are "real". Furthermore they represent direct heating of the atmosphere (non GHGs) and the water supply, which are not the best IR emitters. (Exactly how much IR could be coming out water below its surface?)

    In terms of accounting, this is very different from the 2.9 W/m2 that is being "slowed" down by GHGs but eventually makes its way up and out. Seen this way, I would even venture to suggest that the real comparison should be between 0.028 and zero. If not, what part of the 2.9 W/m2 is not making its way out?
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  8. Any difference between a warm rock and a warm engine, thermally speaking, RSVP?
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  9. A waste heat discussion at RealClimate:

    http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/
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  10. No no Doug, the undersea volcanoes that are warming the sea. Surely you know about them? Plimer does.

    No, seriously, good to see "waste heat" put into context, I have seen it presented seriously as an argument on threads relatively recently. Including, unless I am going crazy, waste heat from air conditioners near monitoring stations. Actually warming the planet that is, not just the nearby thermometer.

    These kinds of propositions are put forward with never any research into the relative proportions concerned, and it is good to see John's diagram. Not, of course, that it will stop someone, on the very next thread, from again saying "what about waste heat?">
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  11. Long term and massive use of nuclear and geo-thermal energy would warm us, according to Eric Chaisson:

    http://www.tufts.edu/as/wright_center/eric/reprints/eos__agu_transactions_chaisson_8_july_08.pdf
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  12. Marcus @#1

    Are you sure what you say is correct? The term 'waste heat' is, I think, rather confusing.

    As I understand it, the heat generated by human beings -- which is the 'waste heat' we're talking about -- has nothing to do with how thermally-efficient our houses, factories and other activities are. Clearly the vast majority -- if not all -- of the energy used by humans will end up eventually as heat, even if it's doing useful work. So the total amount of 'waste heat' must be, by definition, the sum of the energy contained in all the fuels we're burning.

    As the total amount of fuel burnt by humans has increased steadily since the 19th century, so the amount of heat being produced and absorbed by the environment has increased. But as most of the fuel we consume also produces CO2 then the waste heat build-up adds to the heat retained by the greenhouse effect at a similar rate (though in a different proportion).

    However, as others have said, 'waste heat' -- which I'd suggest is better called 'by-product heat' -- represents only a tiny percentage of the overall anthropogenic warming.

    This is a lay explanation of the science as I understand it from reading what others have said, so maybe one of the scientists can confirm that my understanding is correct.
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  13. I agree John. Despite the greater efficiencies, we use more energy and hence produce more waste heat today than we did in the past.


    Breaking heat sources down:

    1. Heat generated from fuel use, this includes heat emitted at power stations/generators and from the use of products that use the energy produced from fuels, the manufacture of products etc.

    2. Heat emitted by the earth. eg. all forms of geothermal.

    3. Heat from solar sources. This indirectly includes renewable energy, although for the for-see-able future renewables will also have other energy inputs as well.

    4. Stored energy in atoms (nuclear energy). I suppose in some respects this can be lumped in with geothermal, although nuclear energy is human activated.
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  14. doug_bostrom at 17:50 PM on 27 July, 2010
    Any difference between a warm rock and a warm engine, thermally speaking, RSVP?

    A warm rock is not shrouded with a cooling circuit pumping excess heat to a heat exchanger and elevating the temperature of air (N2, O2). A warm rock radiates whatever heat it has accumulated from the Sun during the day and delivers it back to the heavens where it came from. Some of this heat, in fact, does heat up the surrounding air by convection as does the engine, but about 150 years ago this didnt seem so interesting to scientists in explaining the effect of GHGs. In any event, whatever heat "doesnt make it back to where it came from" is responsible for leaving global temperatures at it natural level. Also, it is interesting to note that the hotter the rock gets, the more it wants to radiate. This is very different from the warmed up air from the engine which is lingering and is in no "hurry" to cool. It will only give up this energy in fact when it runs into something cooler. Something on the surface of the Earth. Not a hot rock of course. Something cooler, like ice.
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  15. Thanks for this thread, John.

    RSVP writes: In terms of accounting, this is very different from the 2.9 W/m2 that is being "slowed" down by GHGs but eventually makes its way up and out. Seen this way, I would even venture to suggest that the real comparison should be between 0.028 and zero. If not, what part of the 2.9 W/m2 is not making its way out?

    There is no difference in "quality" between the 2.9 W/m2 from radiative forcing and the 0.028 W/m2 from anthropogenic waste heat. A watt is a watt! There is no magic Heat Fairy who sits in the atmosphere and says "This packet of energy came originally from absorption of IR by a CO2 molecule, so I'll make it go away; that packet came from someone's car engine, so I'll keep it around and let it accumulate."

    Effectively all of the heat from IR absorbed by GHGs is shared with the rest of the atmosphere including the O2 and N2 that RSVP thinks are somehow noteworthy here. It's not kept in solitary confinement in CO2 molecules, isolated from the rest of the system until it radiates outward into space.
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  16. RSVP writes Seen this way, I would even venture to suggest that the real comparison should be between 0.028 and zero.

    I didn't really notice this earlier, but there seems to be no dispute over the actual accounting of waste heat. Instead, RSVP's actual claim seems to be that the greenhouse effect does not exist (heating from CO2 should be "zero").

    If that is in fact the real position motivating RSVP's involvement here, this discussion is almost certainly going to go nowhere.
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  17. Ned
    I am glad you noticed that. However it doesnt mean I am denying greenhouse effects... at least those that may have elevated temperature from subzero conditions millions of years ago.

    Even though it is getting off topic, I did also notice to something you wrote on the Waste Heat thread which is related to what you have brought up here.
    <<
    Ned
    "Likewise, most of the heat from GHG absorption will also be transferred to O2 and N2 molecules, thanks to the fact that each CO2 molecule collides with N2 or O2 molecules roughly one billion times per second."
    >>

    Whether you realize it or not, the more you defend CO2's efficiency in transferring energy, the less significance you are actually attributing to the effects of CO2 concentration level.
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  18. Ned
    "There is no difference in "quality" between the 2.9 W/m2 from radiative forcing and the 0.028 W/m2 from anthropogenic waste heat. A watt is a watt! "

    I think I did explained above that the "rate" of transfer for the same temperature is higher via radiation then convection... please check these formulas..

    http://biocab.org/Heat_Transfer.html

    Convective heat transfer (i.e. air needing to cool) is a function of a difference in temperature, whereas radiative cooling goes as T exp(4).
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  19. I suspect if there is such a thing as waste heat, there is also waste cold somewhere.
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  20. RSVPsaid
    "Whether you realize it or not, the more you defend CO2's efficiency in transferring energy, the less significance you are actually attributing to the effects of CO2 concentration level"

    As a layman, having listened to both sides, that is my thinking at the moment.
    And all the IR emitted from the earth is being absorbed by CO2, hence adding more will have very little extra effect on atmospheric temperatures.
    But what happens at night in say a cold region? Won't 1/2 the IR rad from CO2 be radiated back to earth if the temperature of the earth is lower than that of the atmosphere? So there would be some heat energy returned by CO2 to the surface.
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  21. RSVP said:
    "A warm rock radiates whatever heat it has accumulated from the Sun during the day and delivers it back to the heavens where it came from. "

    The Ville:
    With a delay caused by GHGs. Hence as John Cook has pointed out, we have warmer evenings.

    RSVP said:
    "In any event, whatever heat "doesnt make it back to where it came from" is responsible for leaving global temperatures at it natural level."

    The Ville:
    Levels that can be altered. Your use of 'natural level' implies to many that there is some fixed level, there isn't.


    RSVP said:
    "Also, it is interesting to note that the hotter the rock gets, the more it wants to radiate. This is very different from the warmed up air from the engine which is lingering and is in no "hurry" to cool. "

    TheVille:
    You are talking about materials science and engineering. If the 'rock' were a lump of metal it would behave in the same way as a car. ship or any other metal object.
    It will radiate heat and transfer heat by conduction or convection. I don't think anyone here was interested in going into such ridiculus detail.
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  22. RSVP writes: Whether you realize it or not, the more you defend CO2's efficiency in transferring energy, the less significance you are actually attributing to the effects of CO2 concentration level.

    Why? What's the connection? You're just making stuff up.

    Longwave infrared radiation is absorbed by CO2 molecules (and other greenhouse gas molecules). That process is dependent on the concentration of CO2 molecules in the atmosphere; the presence of other "transparent" gases is mostly irrelevant (I write mostly because there are minor technical exceptions that are not relevant to this discussion).

    Individual CO2 molecules exchange energy with the rest of the atmosphere via collisions with other molecules. For a given molecule, the rate of these collisions is dependent on the overall density of the atmosphere, not the concentration of CO2 in the atmosphere -- of the billion or so collisions per second that a CO2 molecule experiences near sea level, most of them will be with N2, O2, H2O, etc. rather than with another CO2 molecule.

    With all due respect to my good e-friend Doug, the "rock" analogy is not really all that helpful here. Waste heat from anthropogenic sources is mostly put directly into the atmosphere, as RSVP notes. Likewise, the warming from GHGs all occurs within the atmosphere.

    As I said in the other thread, every CO2 molecule is effectively a tiny machine using longwave IR as fuel and putting out waste heat into the atmosphere. It's just that the flux from these molecular machines is 100X greater than the flux from our crude mechanical devices down here on the surface.
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  23. On a related note, I recently compared the total heat content increase in the oceans between 1994-2007 (Lyman et al 2010) and total global energy consumption during the same period (World Bank):

    1994-2007 Global Energy Use: 0.578 (10^22 joules)
    1994-2007 Ocean Heat Content Gain: 13.5 (10^22 joules)

    In short, the increase in ocean heat content during that period is 23 times greater than all of the energy used by humans during the same period. If we wanted to heat the ocean, we are doing a far better job heating it with greenhouse gases than we possibly could with direct heating.
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  24. AWoL writes: And all the IR emitted from the earth is being absorbed by CO2, hence adding more will have very little extra effect on atmospheric temperatures.
    But what happens at night in say a cold region? Won't 1/2 the IR rad from CO2 be radiated back to earth if the temperature of the earth is lower than that of the atmosphere? So there would be some heat energy returned by CO2 to the surface.


    There are not two stockpiles of heat in the atmosphere, one that comes from CO2 and one that comes from everything else. This is the fundamental misconception that RSVP is laboring under.
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  25. 17.RSVP at 20:27 PM on 27 July, 2010

    Imagine the atmosphere is only O2 and N2. Energy in the form of Short wave (light) radiation from the sun is incident on the earths surface where some is absorbed. Energy is transferred, the surface “warms”. Some of this energy is re-emitted from the surface as longer wavelength IR (infra red) radiation. As N2 and O2 are tightly bonded and not resonant at IR the longer wavelengths do not interact with these molecules, and IR would pass to space unimpeded. Conduction at surface, diffusion, convection would operate to ultimately increase the kinetic energy of the bulk N2 and O2, the molecules move faster, they “warm”, but radiative transfer as such is “black body” whether from Earths surface or from individual N2 and O2 molecules in Atmosphere. An equilibrium is reached, Earths surface and atmosphere warms to a given temperature.

    Introduce some CO2 into the atmosphere. CO2 molecules have bending bond resonances which are excited by IR wavelengths. IR is strongly absorbed. Less is radiated directly to space. Where does this energy go? The CO2 molecules increase their kinetic energy and internal energy. They “warm”. This internal energy is released (no net gain) when the molecules re-radiate (or cool) at peaks in IR according to same bond resonances. Now, some of this IR re-radiates downwards to contribute to surface warming (now we have net heat gain at surface). This extra kinetic energy is also transferred by direct collision, diffusion, as well as conduction from warmer surface and more convection so that bulk atmosphere warms more than in the non CO2 case (net gain in atmosphere).

    In the greenhouse case there is an extra contribution from the re-radiated energy from wavelength specific absorbed IR by CO2 (and other greenhouse gases). This is the energy that would have escaped to space in the non greenhouse scenario. A new equilibrium is reached as Earths surface and atmosphere “warms” to a higher temperature. Maybe?
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  26. Peter, that is a useful explanation, but as I mentioned we seem to have left the topic of waste heat -- everyone seems to be OK with the figures provided by Flanner 2009 -- and we're back on the topic of the fundamental principles of the greenhouse effect and the spectral properties of gases.
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  27. Just wanted to mention that while "waste heat" is rather low compared to CO2, it is rising as well. Furthermore it is radiated back at Earth just the same through GHG (Warmth = Warmth = IR).

    Just because it is tiny compared to GHG, it doesn't mean it isnt important. 1% compared to greenhouse warming isn't much now, but if we are able to limit emissions of GHG, at one point the need for limiting waste heat will arise. In a few hundred years, that is.
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  28. There is one other thing that bears looking into regarding this paper. NCDC Map shows that climate sensors have a higher concentration in the same areas that AWH is the highest. While this post gives a number of .028, the number is much higher in areas where climate sensor density is higher. "but over the continental United States and western Europe, it is +0.39 and +0.68 W/m^2" (Flanner). Flanner gives 0.39 W/m^2 for the continental US, but he doesn't give a number for the US east of the Mississippi which is probably in line with Europe's number. This can skew climate data regardless of whether the climate sensor is placed properly.

    Second, the local effect of AHW is very much higher on the US East Coast and this has to contribute to warming of the Gulf Stream.

    Third, AWH, being based on consumption primarily of coal, petroleum and nuclear continues through the night which may skew night time temperatures as measured in areas where there are high concentrations of sensors and sources (the East Coast).

    Fourth, AWH is also correlated with another greenhouse gas release, H20. This is also true with nuclear power where cooling towers are used.
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  29. RSVP - "I think I did explained above that the "rate" of transfer for the same temperature is higher via radiation then convection... please check these formulas.."

    No need to check formulas, you're going wrong somewhere else. How does longwave radiation leave the atmosphere?, radiation? or some other mechanism?.
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  30. TOP, you seem to be assuming that 'climate sensor density' increases the impact of a particular region on global temperature reconstructions. That would only be the case if all the results were added up and divided by the total. In actuality results are computed based on geographic distribution... thus 100 temperature stations in New York City have the same impact on the total global temperature reconstruction as ONE temperature station in a Kansas cornfield the size of New York City.

    _Flin_, the temperature forcing from 'waste heat' will not equal CURRENT GHG forcing until the human race uses roughly 100 times as much energy as it does now. From 1950 to 2000 energy use quadrupled... and the growth rate has since slowed. Thus, it will be at least several centuries before waste heat begins to be a problem similar to current AGW effects. In that timeframe we will likely convert to solar and wind power (indeed we must unless we go nuclear) and then just be 'moving around' energy already in the system... and the 'waste heat' issue disappears. Ergo, it is unlikely to ever be a real concern.
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  31. doug_bostrum
    Any difference between a warm rock and a warm engine, thermally speaking, RSVP?

    Yes.

    1. Depending on the temperature of the warm rock, the heat may or may not be captured by CO2 since CO2 has a very narrow band in the IR where it will capture heat and the IR band in which the hot rock radiates changes with temperature. H2O in the atmosphere has a much higher chance of capturing the hot rocks IR radiation.

    Think of the desert where the temperature falls like a rock when the sun goes down (pun intended). Desert areas are a good indicator of the effect of GHG because there is little effect from H2O acting as a GHG.

    2. A hot engine is shielded from radiating directly to space by an insulated sheet metal shield (the vehicles body). Therefore the heat loss of the engine is primarily through conduction to the air and then convection.

    3. Waste heat from a power plant is generally carried away by a cooling tower or placed into a water body. In either case it transfers heat to the atmosphere by either convection or phase change. Since either form of removal results in an increase in the green house gas H2O there is another forcing resulting from this form of waste heat.

    4. Waste heat from the use of energy is primarily put back into the atmosphere by means of convection (think the heat coming from your monitor and cooling fan as you read this post).
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  32. TOP - "Since either form of removal results in an increase in the green house gas H2O there is another forcing resulting from this form of waste heat."

    Are you saying, what you seem to be saying?.
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  33. John Cook, (original post)

    John Cook and Gentlemen:

    Your 'Greenhouse Warming' of 2.9W/sq.m is only half the story. The good Dr Trenberth has shown us that the net TOA imbalance by his calculation is in fact 0.9W/sq.m when cloud, aerosols, albedo, feebacks and radiative cooling are taken into account.

    So the Earth is not warming at 2.9W/sq.m -- rather more like 0.9W/sq.m. As we know also - as of Aug09 - he could only find about 0.55W/sq.m in land and OHC.

    As for waste heat; here is a more interesting sum:

    Globally the rate of 0.028W/sq.m gets much bigger if you reduce the sq.m from which nearly all of it emanates. Not much human industry or population on the oceans (71%) or the Arctic and Antarctic, or the vast deserts or steppes. I believe only about 6-8% of the global surface is producing this human/industrial waste heat.

    Some will be much more concentrated around urban and highly industrialized centres.

    So 0.028 divided by say 0.07 (7% of the global surface) becomes 0.4W/sq.m heat flux over these inhabited areas. A figure of 0.3-0.5W/sq.m has been quoted for the continental USA.

    This is not small in comparison to the purported TOA imbalance of 0.9W/sq.m. for those areas (which are also on the globe).

    So UHI effects being concentrated further and general effects over industrial populations should have a significant effect on land temperatures in that 6-8% of the global surface.

    Of course BP and others have fought out the UHI vs population density relationships elsewhere, but the issue of how much of the 6-8% of the global surface accounts for all the GHCN core data records is a live one for those more expert than me.
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  34. TOP, your points 2, 3, and 4 are actually part of why waste heat is so directly comparable to the radiative forcing from GHGs.

    Doug's large boulder loses some heat by radiation and some by conduction into the ground. Waste heat from our various mechanical machinations is proportionately more likely to go directly to the atmosphere.

    Likewise, the warming from GHGs occurs directly within the atmosphere. TOP and RSVP seem hung up on the idea of the surface losing heat via radiation ... but the warming that occurs, and the 2.9 W/m2 forcing, is the absorption of radiation within in the atmosphere. All of the 2.9 W/m2 are transferred to the atmosphere, and once there, they behave exactly like the 0.028 W/m2 from waste heat once it gets in the atmosphere.

    The origins of the two sources are different, but once they're in the atmosphere, they behave identically. The only difference is that 2.9 W/m2 is two orders of magnitude greater than 0.028 W/m2.
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  35. TOP, RSVP, others - regarding sources of heat energy and it's distribution:

    Heat can enter the atmosphere via convection, latent heat, conduction, and radiation. Convection from a radiator or a hot rock (that doesn't radiate at IR wavelengths, an odd statement considering the data I found here on rock-forming minerals) warms the immediate area, while IR radiation tends to get absorbed within the first 10 to 100 meters. But all of the energy will get absorbed, at least until it has a chance to go somewhere else.

    After that, the source of the energy does not matter. The temperature of the air goes up. the 10^9 collisions/second/molecule distribute the energy to all molecules in the air mass, whether O2, N2, CO2, CH4, Ar, whatever. Energy has been added to the system.

    At atmospheric temperatures, CO2 and other greenhouse gases will radiate energy. Tropospheric convection will occur. Water vapor will circulate, with evaporation and rain moving energy around. And eventually, that energy will radiate from the top of the atmosphere as longwave infrared radiation.

    But there is no difference in the heat from different sources. A joule is a joule, a photon is a photon, and unlike Arizonans, they don't carry ID cards indicating where they are from. And given that industrial energy usage is 1% that of GHG entrapment, industrial heat isn't an issue at this time.
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  36. Ken points out that a 2.9 W/m2 forcing from greenhouse gases doesn't represent the full picture, since there are other negative (and positive) forcings and feedbacks.
    John Cook nicely summarizes these different forcings and feedbacks here:

    CO2 is not the only driver of climate

    However, introducing the other factors obscures rather than clarifies the role of greenhouse gases.

    Let's consider my body mass as an analogy for the atmosphere. I'd like to keep it in equilibrium! There are a mix of positive and negative forcings (basically, eating tasty stuff makes me gain weight, while exercising makes me lose weight).

    Let's say I'm both eating a lot and putting a lot of time into exercising, but the former outweighs (ha!) the latter, so my weight is slowly increasing at 3 kg per year.

    If the question is "how far out of equilibrium is my body's mass balance" then we need to look at all the positive and negative drivers.

    But if the question is "which is responsible for my weight gain, the toast I have for breakfast or the heaping bowls of ice cream I have after lunch and dinner" then we just want to compare the magnitudes of those two individual forcings.

    In case the analogy isn't clear, in this case the toast represents the waste heat and the bowls of ice cream represent the greenhouse gases...

    :-)
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  37. “But there is no difference in the heat from different sources.”
    Really?

    Let's see: “... but over the continental United States and WESTERN EUROPE, it is +0.39 and +0.68 W m−2, respectively.”

    To be "showy" suggesting a temperature records from the U.S. - the warmest 10 years: 1934-1998 (1.24), 2006, 1921, 1931, 1999, 1953, 1990, 1938, 1939/54/87/2007 (0.84) , and: NH (24-90 N), the warmest 10 years: 2007 (1.09), 2005, 2006, 2003, 2002, 1998/2001, 2004, 1999, 2000 (0.68) ...

    Let's see where those records (2006/7) have occurred in the NH - WESTERN EUROPE: http://www.wiz.pl/obrazki/rekordowe_09_08.jpg (Mean temperatures of subsequent 12 months in 2006/2007 higher than ever in the history of obserwations - source: Climate change and extreme event ..., Kundzewicz, 2008, page 7), very carefully (extremely carefully !) areas with a record temperature of overlap areas of greatest heat production (industrial centers, large urban agglomerations). This is particularly evident in the example: Italy, Spain, Great Britain, Portugal, South France, Scandinavia ...

    Once again it is worth recalling: de Laat, ATJ, 2008: "Current Climate Impact of Heating from Energy Usage: The global average primary energy consumption (0.03 watts per square meter) is relatively small compared to other anthropogenic radiative forcings, as summarized in the recent Intergovernmental Panel on Climate Change report. NEVERTHELESS, despite its RELATIVELY SMALL magnitude, waste heat may have a CONSIDERABLE IMPACT on local surface temperature measurements ...”,
    “On a city scale, such as central New York or Tokyo, energy use can exceed 100 watts [!] per square meter [Makar et al., 2006].” , “… Block et al. [2004] used a regional climate model to investigate the magnitude of warming in WESTERN EUROPE caused by adding 2 watts per square meter of energy at the model land surface. Although the model simulation was performed for just 3 months during spring, the results nevertheless indicate that warming does occur, and—under FAVORABLE CONDITIONS—it can on average be as large as 1°C [...] for the 2 watts per square meter surface forcing.”
    “In addition, the spatial inhomogeneous distribution of the waste heat effect may actually have a much larger impact on local and regional [!] atmospheric circulation than what could be expected based on their global average. This impact can be larger than the local to regional impact of well-mixed greenhouse gases [ Matsui and Pielke , 2007].”
    “There is some observational evidence that waste heat has changed temperatures not only locally but also regionally [!!!]. Several recent papers [ de Laat and Maurellis , 2006 and references therein; McKitrick and Michaels , 2007 and references therein] suggest that a link exists between observed warming patterns and industrialization or urbanization. For example, there is considerably more surface than free tropospheric warming in the EASTERN UNITED STATES, suggesting the presence of a surface warming process [ Kalnay et al. , 2006; and references therein].”

    “FAVORABLE CONDITIONS” - remember that the areas of heat production there is often a strong local greenhouse effect (ozone, water vapor), much of it more efficient mechanical thermal insulation: smog - chemical and photo-chemical, standing for many days urban and industrial areas of high pressure, nocturnal boundary layers (NBL), etc., etc.,

    Real Climate, T. Rogers, 30 october 2009: “My interest was to compare the possible effect of waste heat on the temeperature of urban areas. To do this I made some (wild!?) assumptions that 50% of the world population lived in urban areas but 90% of waste heat was released in urban areas (power stations, industry and residential vs residential/low tech in rural areas). I used world population and a an estimate of urban population density to calculate an estimate for the area of the earth’s surface that was “urban”. Using this method I obtained figures for waste heat in urban areas of 7.7 W/m^2 in 1900 and 20.6 W/m^ in 2000. [!!!] THESE SEEMED LIKE FAIRLY SIGNIFICANT NUMBERS TO ME.”
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  38. Do not miss my favourite on the subject... who actually managed to publish on the subject in a journal...

    http://westerstrand.blogspot.com/2008/09/its-that-time-of-year.html
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  39. I think one lay question that needs to be answered is this:

    "OK, the deniers are telling me that CO2 is only a tiny % of the atmosphere so how could any change in that possibly affect the global temperature. And they go on to say that human caused CO2 is small in relation to that. And, OK, I've seen your explanation as to why this is not so, that humans are adding to the CO2 and that it's a greenhouse gas, I get it.

    So, seeing as how the human caused warming is only a small % of the total earth warming, isn't that the same thing?"

    Also, isn't heat pollution an issue that is a problem in some localities (like near nuclear plants) and may actually become a global problem someday?
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  40. dcwarrior, no it isn't the same thing at all. We're dealing with two different examples of pure denial;

    In the first case the claim is that a small percentage cannot have a big impact (e.g. CO2 as a small percentage of the atmosphere cannot cause warming, brakes as a small percentage of a car's mass cannot cause the vehicle to slow down).

    In the second case the claim is that a small percentage coming from source A is more important than a large percentage coming from source B (e.g. global warming is being caused by the 1% 'waste heat' NOT the 99% of additional heat from GHGs, air friction slows a car 1% as much as brakes do... therefor it is air friction stopping the car, not the brakes).

    Yes, heat from human industry can be a somewhat significant issue on local scales. It is the second most significant cause of the 'urban heat island' effect... but even there most of the localized heating is from land use changes. On a global scale we would need to burn vastly more fossil fuels than we currently do (indeed, vastly more than EXIST on the planet) in order for industrial heat to be an issue. If we converted fully to nuclear power then maybe in a few hundred years it would start to be significant... but far more likely we'll convert to mostly wind and solar power (which don't release any 'extra' energy that had been stored).
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  41. I should probably revise the analogy I used above.

    Apparently, a slice of whole-wheat toast has about 80 kcal. To make the analogy apt, I would have to be eating somewhere around 8000 kcal of ice cream per day. I don't think that would be possible.

    So, to keep the quantitative proportions correct, let's say we're trying to determine whether my weight gain is due to the daily 2 cups of ice cream or the one-eighth of a slice of unbuttered toast.

    I think that gives the appropriate two orders of magnitude difference.

    So, what RSVP is saying is basically "Don't worry about eating that pint of Ben & Jerry's ... it's that one bite of toast that's making you gain weight."
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  42. TOP, there is only one difference in the grand scheme of things as viewed from the top of the atmosphere between a warm rock and a warm IC engine. The rock was warmed by insolation, the engine by liberation of energy stored in fossil fuels. Heat liberated by whatever means and no matter how many times the energy of that heat is bounced from hand-to-hand remains ideologically sterile from the perspective of how it escapes Earth.

    Remove the engine from your car. Warm a boulder of similar mass in the sun. Place it in the engine compartment of your car. Close the hood. Does the warmth emerging from the car by a combination of conduction and radiation know where it came from? Does it behave in a special way? Are joules endowed with a sense of history?

    This is a rather mind-blowing discussion!
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  43. dcwarrior at 00:50 AM on 28 July, 2010

    Here's a lay answer, assuming I'm understanding your lay question correctly.

    'Waste heat warming' and 'CO2-caused warming' are two completely separate mechanisms. The fact that anthropogenic 'waste' heat -- that I prefer to call 'by-product heat'-- is insignificant compared with the heating we receive from the sun, has no relation to the effect the small percentage of anthropogenic GHG releases are having on the atmosphere.

    That the waste heat is insignificant is explained in the many posts above. The fact that a relatively small percentage of anthropogenic GHGs can change our climate is because up until the time humans started to burn fossil fuels in large quantities, naturally-occurring GHGs, were in equilibrium with the natural processes that locked them up in the Earth's geology: our planet was in a steady state. However, the small but growing anthropogenic percentage of GHGs are the proverbial straws that are accumulating on the camel's back, and which in time will break it. The proof of this is that the CO2 concentration in the atmosphere has increased from around 280ppm to 387ppm+, since the industrial revolution began (it had previously been stable for 150,000 years or more).

    You can find more here.

    I hope that helps.
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  44. dcwarrior:

    "OK, the deniers are telling me that CO2 is only a tiny % of the atmosphere so how could any change in that possibly affect the global temperature. "

    The Ville:
    They are ignoring the total picture. CO2 and other greenhouse gases respond to radiated heat.
    In the IR spectrum, CO2 is about 9% of the warming atmosphere. Water Vapour in the region of 80% or so, although it fluctuates a lot.
    You'll also find skeptics and deniers suggesting water vapour is more a more abundant greenhouse gas, which sort of negates the idea that CO2 is a trace gas!
    eg. they contradict each other.


    dcwarrior:
    And they go on to say that human caused CO2 is small in relation to that.

    The Ville:
    The issue is what impact our additions make to the system and what other impacts humans have on the system. It is the total increase in atmospheric CO2 as a result of changes in sources and sinks that cause more warming.
    eg. a small change in atmospheric CO2 leads to other effects which increase greenhouse gases further, causing more warming.



    dcwarrior:
    So, seeing as how the human caused warming is only a small % of the total earth warming, isn't that the same thing?"

    The Ville:
    Your conclusion is incorrect based on the previous incorrect assumptions.
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  45. Doug, I yield to no one in my admiration of your contributions to this site, but I still don't understand the point of the rock. Maybe I'm dense as a rock myself, but it doesn't really seem to clarify anything for me.

    I think it's much more helpful to keep the focus on what happens in the atmosphere. Waste heat warms the atmosphere, greenhouse gases warm the atmosphere. Once that warming has occurred, there's really no difference between the two -- aside from the two orders of magnitude difference in quantity.

    If anything, dragging in that rock just caters to RSVP's misconceptions and his focus on what happens on the surface instead of what happens in the atmosphere.
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  46. I just want to say that I "have" captured the message from posters that AGW represents climate forcing two orders of magnitude greater than "anthropogenic waste heat". I explain above however how "watts is not watts", but this was ignored (or not comprehended).

    This point aside, it is interesting to note what happens to the label "deniers" in this context. The idea of waste heat being responsible for global warming would be a most "inconvenient truth" indeed, as most are likely to harbor that if this is the real problem, there is no (sustainable) solution.

    If so, this would be very ironic indeed. Ironic if one believes in AGW only because a magic wand supposedly exists (i.e., getting rid of fossil fuels).
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  47. RSVP #46 wrote: "I explain above however how "watts is not watts", but this was ignored (or not comprehended)."

    The latter. No one comprehends it... because it is self-evidently false. 2 is 2, up is not down, and watts are watts. Energy going into the atmosphere from solar heating is exactly the same as energy going into the atmosphere from human industry. Every watt of either will interact with the climate in exactly the same way.

    Also, as I explained to you previously, if heat generated from combustion of fossil fuels WERE causing global warming the sustainable solution would be exactly the same as that here in reality... stop using fossil fuels. There is more than enough solar and/or wind power to replace fossil fuels, and since they use energy already present in the climate system (rather than 'locked away' in the ground) they wouldn't be introducing 'new' heat the way fossil fuels do.
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  48. RSVP - Therein lies the rub. Once in the atmosphere, watts (joules) and photons are just that, energy. Conduction/convection heat an area within about 2 meters (figuring a car engine in the open), IR heats an air mass over 10-100 meters of absorption, and once that's happened it's just energy in the air. Energy used gets dissipated as heat - whether it's electrical, mechanical, waste heat from power generation, whatever, it will eventually come out as heat.

    There's no Maxwell's demon choosing joules of heat energy based on their origin, no ID cards on the photons - you have warm air. There is no difference in what happens to those joules of energy once they have dissipated into the atmosphere.

    Watts is watts. No ifs, ands, or buts, no qualifiers. Once it gets into the system it's just indistinguishable watts. The frustration you may sense in some of the posts is due to an inability to understand how that simple fact could be denied.

    So - back to the orders of magnitude. The 1% of energy from AHF compared to the 99% of energy from GHG entrapment? As Ned put it in the related thread:

    If you eat a single saltine cracker AND a pint of ice cream a day (all of which go into calories once digested), which do you think makes you put on the pounds?
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  49. CBD and John Russell - thanks. Could you get even more succinct by saying (I am pretty sure my facts are wrong here, so maybe someone can tune it up), the CO2 greenhouse effect works by adding small amounts of CO2 to the atmosphere faster than the natural processes get rid of it, and thereby causes more heat to be retained in the atmosphere than would otherwise be the case. In theory, the waste heat works the same way, only, the amount of excess heat caused by humans is [100x?] less in relation to all heat produced in nature than man-made CO2 bears to the CO2 in the atmosphere. Humankind would have to create a lot more heat in order for that to be a problem.

    The Ville, I think you are factually correct, but I don't think someone who didn't already agree with you would be convinced by that argument.
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  50. Ned, thanks! I'm trying the Chuck Yeager approach w/regard to being in a flat spin or similar baffling circumstance, paraphrased: "Keep on flying the airplane, keep on trying different things, don't assume you're going to augur-in just because the first thing you tried failed."

    I'm trying to push different buttons. I'm still not sure what the problem is here, but the whole matter reminds me of the "smart photons" we dealt with earlier, the photons that as it turns out don't know the temperature of objects impinging on their future path. I'm getting the sense here that energy from AHF is supposed to be different somehow, knows where it came from and thus must behave differently in the future.

    TOP implies that heat escaping from an iron engine block at a given temperature is different somehow from that which would escape from a similar store of heat derived from a source not supplied by liberation of chemical energy and stored in a rock. We know that's not the case. TOP must accept that or give a reasonably detailed, plausible explanation consistent with the real world of how it is otherwise.
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