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Comments 114401 to 114450:

114401. Ned at 21:43 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114402. Alden Griffith at 21:41 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114403. Ned at 21:40 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114404. Pete Ridley at 21:34 PM on 27 July 2010
        Models are unreliable
        Peter Hogarth, ref. #204, I think that Physicist Luboš Motl’s blog thread “John Cook: Skeptical Science” (Note 1) Item 4 should help you. Motl says “It's cooling: Again, Cook's graphs and statements are obsolete and a few years from the moment he wrote the page were enough to falsify his new predictions about the accumulating heat. The reality is that between 1998 or 2001 or other years on one side and 2009 on the other side, the global mean temperature dropped. Sometimes it's cooling, sometimes it's warming. The year 2010 is likely to be much warmer than 2009, approaching the temperatures of 1998, but when the El Nino fully switches to a La Nina, things can be very different. The fact that there's been no significant warming for 15 years has been accepted by both sides of this debate. And since 1998, it's just cooling. Cook has no counter-arguments. He just says that the heat flows influence the temperature and I agree with that. Except that he doesn't show in which way the flows are going to go e.g. in the next 10 years”. Motl also comments at Item 5 about this thread with “Models are unreliable: Cook says that models have made predictions that were successfully compared to observations. Except that this is not enough for the models to be reliable. For them to be reliable, it would have to be the case that the models have produced no predictions that were inconsistent with the observations - because one wrong prediction is enough to falsify a model. Clearly, such falsification has taken place with all of them. In particular, all IPCC-endorsed models predicted a warming since 1998 that didn't occur. They're gone. Again, both sides agree that we can't rely on them. Kevin Trenberth agrees that the disagreement of the models and the data is a travesty. There are hundreds of recent examples showing how deeply flawed the existing IPCC-endorsed models are”. KR, Here are Motl’s comments about those global temperature measurements you were on about in #203 “Temp record is unrealiable: In his counter-point, Cook talks about the urban heat island effects that are "negligible". Well, they're surely not negligible because the estimated urban warming in typical large cities exceeds the whole assumed warming caused by CO2 - something like 0.6 °C. So it matters a lot whether the urban effects are isolated. But the urban effects are far from being the only problem with the surface temperature record. The number of recently found dramatic problems with the surface record is so huge that I can't even enumerate them here”. The rest of Motl’s thread is worth reading too – enjoy. NOTE 1) see http://motls.blogspot.com/2010/03/john-cook-skeptical-science.html Best regards, Pete Ridley
114405. CBDunkerson at 21:33 PM on 27 July 2010
        It's waste heat
        RSVP #30, no you really didn't answer my questions - but hey, why not; 1: No. 2: Same as all other heat... it radiates at equal intensity in all directions. 3: "energy dissipation" is two words... and two words neither you nor I have used. Ergo, it is impossible for me to determine what meaning they are meant to have "in this context" because there is no context. 4: Same as all other matter in the universe... they absorb some wavelengths of EM radiation and allow others to pass through. Absorbed radiation is (per issue 1 above) then re-emitted, though possibly at a different wavelength. 5: The wavelengths involved are different. Specifically, Nitrogen and Oxygen are largely 'transparent' to the infrared wavelengths emitted by the planet's surface while GHGs are not. BTW, your hypothesis seems to depend on a belief that waste heat 'goes into' N2 and O2 and stays there (which is completely wrong) while solar heat somehow avoids those two elements. Which is, of course, pure nonsense.
114406. Paul D at 21:28 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114407. Ned at 21:26 PM on 27 July 2010
        The nature of authority
        Ah. AWoL, that clarifies things a lot. In your previous comment you wrote The constant is a theoretical concept and simply,in it's present form does not match the real world which (while perhaps not intended that way) would be "fighting words" to anyone with a background in the physics of radiation. If I understand you rightly, though, you're actually asking about the relationship between emissivity and radiant exitance. For a blackbody, the thermal radiant flux emitted per unit area (M, in watts per square meter) is given by M = sigma * T^4 meaning that it's purely a function of the temperature of the blackbody (in Kelvins) and the Stefan-Boltzmann constant (5.6697 * 10^(-8) W m-2 K-4). In the real world, nothing is a blackbody, though some materials (e.g., water) are pretty darn close. Thus, we introduce the concept of a material's emissivity (the ratio of its radiant exitance to the theoretical radiant exitance of a blackbody at the same temperature): M = epsilon * sigma * T^4 If an object has uniform emissivity across a wide range of wavelengths (again, water makes a good example) we call it a gray body. Some material types have emissivities that are dependent on wavelength (quartz, for example), which makes them a bit more complicated to deal with. Emissivity isn't really a "fudge factor" any more than the "color" of an object is a "fudge factor". In fact, color (spectral reflectance) is a very good analogy for spectral emissivity. There is nothing particularly problematic about using the Stefan-Boltzmann law at typical earth surface temperatures. You can measure emissivity of objects very easily (actually, you can probably find tables with typical emissivity values on the web). So I'm really not sure what exactly prompted your comment up here. To anyone who is used to doing calculations of electromagnetic radiation fluxes it just seems wildly over-the-top. Actually, that comment reads a bit like someone claiming that the field of ballistics is garbage because it's based on Newton's inverse square law, which is purely theoretical and has to be modified empirically to account for air resistance. You write that you "attempted to get information on the application of the constant and the law, at low temperatures, but find that I have to pay for the information, which as a taxpayer rankles somewhat." That also seems kind of strange, since the application of the S-B law at normal earth temperatures is not at all obscure; it's covered in lots of textbooks. If there's some particular very specialized paper that you are looking for, would you mind telling us what it is? (I'm just curious, as it would help understand where you're coming from). I would gently suggest that one of the responsibilities of being a skeptic is appropriately modulating one's skepticism. The three comments here, here, and here might be cases where more discretion would have been in order.
114408. AWoL at 21:23 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114409. kdkd at 21:12 PM on 27 July 2010
        It's waste heat
        RSVP #58 "On the one hand, the more you defend CO2's efficiency in transferring energy, the less significance you are actually attributing to the effects of CO2 concentration level. " Ummm. No. These are two separate processes that are physically independent. Your logic is wrong, and your physics is deficient.
114410. thingadonta at 21:02 PM on 27 July 2010
        Waste heat vs greenhouse warming
        I suspect if there is such a thing as waste heat, there is also waste cold somewhere.
114411. RSVP at 20:40 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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).
114412. RSVP at 20:27 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114413. RSVP at 20:20 PM on 27 July 2010
        It's waste heat
        doug_bostrom I went there and (as before) read... "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." On the one hand, the more you defend CO2's efficiency in transferring energy, the less significance you are actually attributing to the effects of CO2 concentration level.
114414. AWoL at 20:10 PM on 27 July 2010
        The nature of authority
        To Berenyi Peter,post 129. Many thanks for your clear explanation. And to Ned. I am not trolling or seeking to foist radical wacky new ideas on the world of physics. I am not a climate scientist or physicist, but a veterinarian, who has over the years picked up bits of information, some good and some bad.I want to rearrange and check that information. Anyway, the (Stef-Bol)constant is applicable at lower temperatures,and is widely used in the food industry.However,in the article I read, there was a comment to the effect that the computed temperature or heat given off by staightforward application of the formula would be higher than encountered in practice.So an arbitrary factor in the form of "emissivity" was applied. As this,as far as I am aware,is derived empirically, would I be right in deducing that this factor is a combination of actual emissivity(yet to be explained)and a convenient"fudge factor"? If there is a fudge factor,doesn't that point to something "not quite right"? I have attempted to get information on the application of the constant and the law, at low temperatures, but find that I have to pay for the information, which as a taxpayer rankles somewhat. Once again,thanks to Berenyi Peter for his positive response to my post, which perhaps should have taken the form of a question, rather than an assertion.
114415. Ned at 20:07 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114416. Ned at 20:00 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114417. RSVP at 19:48 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114418. Paul D at 19:11 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114419. John Russell at 18:14 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114420. Paul D at 18:09 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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
114421. David Horton at 18:01 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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?">
114422. Paul D at 17:52 PM on 27 July 2010
        Waste heat vs greenhouse warming
        A waste heat discussion at RealClimate: http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/
114423. Doug Bostrom at 17:50 PM on 27 July 2010
        Waste heat vs greenhouse warming
        Any difference between a warm rock and a warm engine, thermally speaking, RSVP?
114424. RSVP at 17:41 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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?
114425. Doug Bostrom at 17:22 PM on 27 July 2010
        It's waste heat
        RSVP I believe we're all clear on that. Flanner is at any rate and since his number is the operative one here we're all on the same page it seems. One more time: AHF (Anthropogenic Heat Flux) is something like 1% of expected forcing from anthropogenic green house gases. As I explained earlier, estimates of AGHG forcing expectations could be too large by a factor of 10 and would still dwarf AHF. "There's no there, there." Meanwhile you still seem to be worrying over the relationship of N2 and O2 w/waste heat. It's not a unique or special connection. Ned explained the commonality here.
114426. RSVP at 17:01 PM on 27 July 2010
        It's waste heat
        Marcus said "heat from within the Earth is going to find its way to the great beyond regardless of birthright, ultimately via radiation. " I agree 100%, but then you go on... "There's really not much to work with here for a so-called skeptic, to the point that one is left wondering how to speak patiently in the face of arguments to the contrary, once they've been repeated several times by the same person. " I have also asked more than several times how N2 and O2 radiate? I have still to see anyone acknowledge this difficulty. There have been some indirect responses about CO2 acting as an antenna! in which case, according to this explanation CO2 is helping to cool the atmosphere, and if this were the case, all latent energy would actually be attributed to waste heat. But lets not go there for now please. I would just like to see an explanation on how N2 and O2 (the non GHG portion of the atmosphere) are understood to cool radiatively, as I have been saying that they cant do this and will only generally cool by convection. And only by convection to "cooler" objects such as water and ice, implying a "selective" route for energy exchange. There was that question of why poles warm faster (for instance). At any rate Marcus, I also agree with your statement, "so much of this "debate" is ultimately driven by complete and total intractability"... This is obvious. I am not sure why, as we are all in the boat together.
114427. RSVP at 16:39 PM on 27 July 2010
        It's waste heat
        I would hope that the term "waste heat" is not being understood simply as that portion of energy that is not delivered to the load. I can see how the word "waste might lead one to think this... thoughtout this discussion, I was referring to the broader concept. For say an automobile, waste heat should be understood as heat exchanged to cool the engine, the car's friction in all moving parts, the kinetic energy increase in the atmosphere left by drag, and combustive heat going out the tail pipe in the form of CO2 and water vapor. Similarly, house heating waste heat is not the percent of heat that escapes though a building's insulation, but every calorie used to heat the inside of a home or building; as this heat is eventually released into the environment. It is actually equivalent to the total worldwide energy consumption... 1.5 x E13 W http://en.wikipedia.org/wiki/World_energy_resources_and_consumption Hope this helps.
114428. Doug Bostrom at 16:36 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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."
114429. David Horton at 16:15 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114430. muoncounter at 15:09 PM on 27 July 2010
        Assessing global surface temperature reconstructions
        #36: " the conclusion that the UHI effect is negligible is not an effective way of looking at this issue." Seems to me that a necessary step in researching something is a consideration of whether or not it is likely to be of negligible significance. But the more important point was somehow missed: If GISS/HAD/GHCN etc are as consistent with UAH/RSS as Ned has shown, then any major revision of one had better also apply to the other. If UHI can profoundly flatten surface temperature measurements, then what 'correction' will do the same to the satellite data? As far as I can discern, UHI doesn't apply to satellite measurements of atmospheric temperatures. "about the ocean temperatures, lets be real, " Point was: Looking at Ned's fig 8, all blue bars are of comparable height. Again, different data sources and interpretations are consistent with one another about the trend. #37: " no surprise that if you run the same core data through a software processing package - you might get similar results." It would require significant explanation if the results were not similar. Ned has shown that the conclusion all competent measurement systems show increasing temperatures on a global scale during this time period is well-founded. But Mr. Lambert's criticism can be inverted: It is no surprise that if you run the same set of selectively chosen points out of a large data volume through a set of preconceived notions, you get the same tired denialist arguments. What is disappointing, however, is how quickly those arguments revert to mere name-calling and accusation. What makes this blog different is, for the most part, the discussion stays on a higher plane.
114431. John Chapman at 14:46 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
114432. Doug Bostrom at 14:09 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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!
114433. Joe Blog at 13:06 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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.
        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.
114434. Marcus at 13:04 PM on 27 July 2010
        Waste heat vs greenhouse warming
        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!
114435. Marcus at 12:57 PM on 27 July 2010
        It's waste heat
        Another problem with the "Waste Heat" theory. Why did the planet continue to warm (due to increased solar activity) during the Great Depression, when industrial activity-world wide-fell, yet temperatures fell during the first decade of the post-war industrial boom?
        Response: Marcus, just to play devil's advocate on this line of argument, couldn't you likewise say "why was there no global warming during mid-20th century while CO2 levels were rising?" or "why was there global warming in the early 20th century while CO2 levels weren't rising that steeply?" :-)
        
        To fully address the question of waste heat during the industrial revolution and Great Depression, you would need to calculate the radiative forcing from waste heat over these periods. It's not that hard to work out - we do have figures on energy use over these periods (I link to the CDIAC data from here). Working this out is left as an exercise for the reader (eg - I'm too lazy to do it myself).
        
114436. Marcus at 12:55 PM on 27 July 2010
        It's waste heat
        There is one obvious problem with the whole "waste heat" argument which is this-why was there little to no measured warming between 1850 & 1900, given the amount of factories & power stations which were pumping out heat during this time? By today's standards, these factories & power stations were incredibly inefficient-meaning they gave off the vast bulk of their energy as waste heat. Yet strangely, in the last 60 years, we're expected to believe that waste heat generation is actually inversely proportional to improvements in thermal efficiency. i.e. the skeptics would have us believe that, even though thermal efficiency has improved over the last 60 years, the contribution of waste heat to global warming is increasing! That's *hilarious*. From my calculations, its fair to say that waste heat contributes somewhere around +0.006 degrees (& falling) to total global warming for the last 60 years.
114437. Doug Bostrom at 11:32 AM on 27 July 2010
        It's waste heat
        Actually this thread is helpful because it's serving as a remarkably clear and concise example of how so much of this "debate" is ultimately driven by complete and total intractability on the part of some of the discussants. This is a very simple situation. "AHF" is capable of adding something like 1% of the quantity of solar heat being retained by additional impedance due to C02 and knock-on effects, working from mainstream estimates of anthropogenic GHG climate sensitivity. Just to make things clearer, let's imagine for a moment that we're somebody akin to Dr. Roy Spencer, a highly-qualified scientist able to make a start on articulating an alternate hypothesis to anthropogenic warming as an explanation for recent observed temperature increases. Under our Dr. Spencer-style hat, we believe that effective AGHG forcing is only 10% of more commonly accepted figures. In this circumstance we're looking at AHF forcing still being just 10% of anthropogenic GHG forcing. Even if we assume mainstream estimates are off by a full order of magnitude, AHF still pales in significance compared to anthropogenic GHGs, is still yet another order of magnitude less. Meanwhile, as has been pointed out, heat is mindless and does not care from where or to where it's going. Whatever heat is added to the pool here on Earth whether by anthropogenic liberation or arriving from the sun or for that matter emerging from retained and radioactive decay heat from within the Earth is going to find its way to the great beyond regardless of birthright, ultimately via radiation. Nothing about the origin of heat specifies its subsequent behavior. Heat flux from energy liberated as a part of human activity by any measure appears by all accounts to be a minor constituent of Earth's radiative energy budget. Even if one looks at the thermal impedance properties of the atmosphere from various outlier perspectives, AHF still does not measure up in a significant way. There's really not much to work with here for a so-called skeptic, to the point that one is left wondering how to speak patiently in the face of arguments to the contrary, once they've been repeated several times by the same person.
114438. Ned at 10:58 AM on 27 July 2010
        The nature of authority
        Berényi Péter writes: You may expect that, but unfortunately reality does not seem to conform. Can you explain, in words, what that figure shows and how precisely it contradicts the claim from chris's post? Thanks.
114439. Ned at 10:52 AM on 27 July 2010
        It's waste heat
        johnd writes: Ned at 22:36 PM, part of the issue being discussed was whether waste heat accumulates or not, and whether accumulative it's effect is more than negligible. There is no magic mechanism that removes heat from the atmosphere if it originally came from radiation but lets it accumulate if it originally came from combustion or whatever. IMHO these analogies to revolving doors and traffic jams seem to have no effect other than clouding the issue. How about some actual evidence, please? Doug B. gave a reference to a paper with quantitative comparison of the two sources way back in comment #2. That was very helpful, I think.
114440. chris at 09:42 AM on 27 July 2010
        The nature of authority
        not sure why I wrote "longitude" when I meant "latitude" in my post just above!
114441. chris at 09:38 AM on 27 July 2010
        The nature of authority
        Berényi Péter at 09:14 AM on 27 July, 2010 "You may expect that, but unfortunately reality does not seem to conform." Careful Peter. One location does not define an entire longitudinal band. You really need to look at the paper I cited (Zhang et al., 2007; link in the post that you mined my sentence from). The 20th century has seen a decrease in rainfall in the equatorial regions from around 0 o longitude to 30 o N, and an increase in rainfall in the high latitudes. Pretty much as expected from models. X. Zhang et al. (2007) Detection of human influence on twentieth-century precipitation trends Nature 448, 461-465
114442. KR at 09:34 AM on 27 July 2010
        It's waste heat
        johnd - False distinction logic error: thermal energy is thermal energy, none of it is 'pregnant' or otherwise distinguishable from the other. This is akin to the G&T arguments where some skeptics thought that an object would somehow 'know' that certain photons came from colder objects, and would not therefore contribute to energy balances. Photons (and joules) don't carry ID cards, unlike Arizona citizens. Thermal energy gets distributed by the usual suspects - conduction, convection, latent heat, and radiation, with radiation measured to be the dominant pathway. The source of the energy is irrelevant to how it leaves. As per the thread, however, only ~1% of that thermal energy comes from energy usage, the other 99% comes from GHG entrapment of solar energy. Bad analogies don't change that. If nothing else, this thread has been a delightful example of logic errors...
114443. Berényi Péter at 09:14 AM on 27 July 2010
        The nature of authority
        #101 chris at 09:17 AM on 25 July, 2010 We expect in a warming world that rainfall will decrease in the equatorial regions of the Earth You may expect that, but unfortunately reality does not seem to conform.
114444. johnd at 09:06 AM on 27 July 2010
        It's waste heat
        RSVP at 06:35 AM, perhaps another analogy may help. A well designed and up to date maternity hospital has been built and access is via a revolving door that is designed to maintain an efficient environment and minimize heat losses by operating only with one person entering and one person leaving at the same time. Only 1% of those entering the hospital do so to give birth, the bulk of those entering, and leaving are visitors or staff. At what point does the hospital board have to go back to the engineers who did the original design calculations, and ask them if the assumption they made that as only 1% of those entering the hospital were pregnant, and so could be considered negligible, was a indeed a valid assumption?
114445. johnd at 08:34 AM on 27 July 2010
        It's waste heat
        Ned at 22:36 PM, part of the issue being discussed was whether waste heat accumulates or not, and whether accumulative it's effect is more than negligible. Obviously if the total heat losses from your dining room, being well insulated one hopes, remains less than that being provided by the burning candles, then it is the total accumulated heat that is relevant in any quantitative comparison at any point of time. Naturally, if at some point of time someone opened a door introducing a period of increased heat loss, that is a period of cooling, then a portion or perhaps all the accumulated heat of the burning candles would be lost.
114446. KR at 07:21 AM on 27 July 2010
        It's waste heat
        Also take a look at Common Sense error, strongly related to the Dunning-Kruger effect
114447. KR at 07:16 AM on 27 July 2010
        It's waste heat
        RSVP - queuing theory, with its associated transition points at certain flow rates, has absolutely nothing to do with this topic, and can only be considered an (rather poor) attempt to change the subject. Your waste heat issue is 1% the effect of GHG entrapment, negligible in comparison. You have shown no evidence whatsoever to the contrary. This is a science blog site - Appeals to Belief and Red Herring logical errors really don't hold up to actual numbers or physics.
114448. Doug Bostrom at 07:07 AM on 27 July 2010
        It's waste heat
        RSVP, imagine that as cars from the rock concert move down the congested highway the mayor of the local city connected to the highway announces that an asteroid is approaching and will strike the center of the city within hours. Many residents respond to the announcement by "getting out of Dodge," ironically jumping into their Dodge automobiles and hightailing it for the proverbial hills. Proportioning the public panic to the relative numbers of AHF forcing versus forcing by a doubling of C02, the highway must then cope with not only the increase of traffic from the concert but a panic stricken flood of drivers representing over 100 times more additional vehicles beyond that created by the concert traffic. Not to put too fine a point on it, you're obsessing over a very tiny number.
114449. Ned at 06:55 AM on 27 July 2010
        The nature of authority
        Actually, I don't know that. It sure seems like that's the impression you're trying to convey in this thread. If not, you might want to try to write more clearly. In particular, using repeated expressions like "According to AGW" and "I am being told that ..." when referring to the basic physics of infrared spectroscopy does not convey the impression of confidence in said spectroscopy. Most people, when writing about something they genuinely believe in, don't feel the need to add a continual stream of parenthetical qualifiers.
114450. RSVP at 06:35 AM on 27 July 2010
        It's waste heat
        An metaphore to "queue threoy" may help you all... There is a highway that goes into the city. The flow is constant everyday (no weekends in this theoretical land). The flow of cars depends on the amount of traffic since the channel (the highway) but in generally is usually constant and flows well. One day Road Maintenance needs to paint the lines on the side of the highway and places cones on the right lane. This slows traffic down slightly. (This might be effects of elevated CO2... perhaps). On top of this however, there is a special event that day (rock concert) and the number of cars increases, but only by 1%. (waste heat) Since the flow was basically optimal before these two occurrences came about, the traffic almost comes to a complete halt. There is now a traffic jam and cars are moving bumper to bumber. Someone in a car wants to see a huge accident to justify this inconvenience. As he passes the cones, he is dissappointed that there is nothing dramatic to see. (AGW guy, asking me for numbers to justify the effects of man made waste heat).

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