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JPostma at 02:14 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
I have used the Stefan-Botlzmann law to give you the answer, as you referenced it, so I am sorry if it was missed within the body of text.
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JPostma at 02:13 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
I did answer that precisely, in fact, to quote:
"An object radiates power P = A*sigma*T^4 where A is the surface area and T is the temperature. If you have two objects in a simplified geometry then you get the heat flow as the difference between their emissions, with heat flowing only from the warmer to the cooler."
Perhaps I am giving too much information, and it distracts you from being able to infer the answer. The answer, is of course, and I am sorry if you do not see the answer in the physics and in the math, that yes, and object radiates power as function of its surface temperature. I do hope this helps, and I hope that you can begin to recognize the greater answer in the math and physics.
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Dikran Marsupial at 02:09 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
"All of the questions have been answered. "
no, you have not answered mine, posed at 71, here it is again for your convenience
Lets try an even more simple thought experiment. Consider a spherical blackbody object (A) at a temperature slightly above absolute zero, in a total vacuum with no other sources of radiation. Do you agree that the object will radiate photons in random directions according to the Stefan-Boltzmann law? A "yes" or "no" answer ought to be possible here, if "no" please state this explicitly and explain why.
This ought to be uncontentious, so you should just be able to reply "yes", in which case we can move on to the next step.
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JPostma at 02:05 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
All of the questions have been answered. I am honestly trying to help you guys out, because it seems to be clear that a few basic thermodynamics and physics concepts might be unknown to you. I truly do not mean to sound patronizing or anything like that in making that statement, that is not my intention at all. So I do apologize for that. I have simply been assuming a certain level of ability to understand physics and thermodynamic concepts, such as the basic equation for heat flow under radiant emission, equilibrium conditions, etc.
The lump of iron is heated by the furnace. The iron does not heat the furnace. The heat flow equation shows exactly how and when the iron is radiating, as would the most basic conceptual understanding of the physics stated in words.
I hope this helped, and again, apologies for assuming certain things to be understood.
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Dikran Marsupial at 01:59 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma, I will not rise to your ineffectual attempts to be patronising ("Please let me know if you still require my help with this"), as I said the question is very easily answered under the modern statistical intepretation of thermodynamics, the fact that you can't (or won't) give a direct answer to MA Roger's question says it all.
Now, perhaps you would like to answer my question (it is the start of a thought experiment, but I thought it would be best to establish something we both ought to be able to agree on as a solid foundation)?
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JPostma at 01:55 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
I have just stated the answer, directly. I am sorry if you missed it again.
Please familiarize yourself with the heat flow equation Q = sigma*(Tf^4 - Ti^4). Is the answer still not clear? It also answers your latest question. Please let me know if you still require my help with this, and I will try to make it clear. An object radiates power P = A*sigma*T^4 where A is the surface area and T is the temperature. If you have two objects in a simplified geometry then you get the heat flow as the difference between their emissions, with heat flowing only from the warmer to the cooler. I hope this helps.
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Dikran Marsupial at 01:47 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma, repeating "The iron will radiate what is required of it" doesn't make it any less evasive.
Lets try an even more simple thought experiment. Consider a spherical blackbody object (A) at a temperature slightly above absolute zero, in a total vacuum with no other sources of radiation. Do you agree that the object will radiate photons in random directions according to the Stefan-Boltzmann law? A "yes" or "no" answer ought to be possible here, if "no" please state this explicitly and explain why.
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JPostma at 01:34 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
Here is the answer, in words: "The iron will radiate what is required of it". I am sorry, I thought you might appreciate the meaning of that, but I suppose I shouldn't do that.
So, if you look at the equation, Q = sigma*(Tf^4 - Ti^4), it is precisely clear when the iron radiates. It couldn't be any more clear. I am sorry if it is not clear to you. The answer is "as soon as the iron has a temperature". Thus, the iron can come to equilibrium with the source furnace, which is acheived when Q = 0, and of course, the heat flor equation shows that heat only flows from the furnace and into the iron while the iron is being heated; the iron will thus not heat the furnace, of course.
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Dikran Marsupial at 01:28 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma wrote "If you truly require me to answer "when" the iron starts to radiate, it is troublesome.",
Well yes, the fact that it is troublesome under your understanding of thermodynamics is exactly the point. It isn't at all troublesome for the modern statistical view of thermodynamics. The fact that you can't state the answer to such a straightforward question, and have to resort to such transparent equivocation, really says it all, and should give you pause for thought (to say the least).
Sorry again MA Roger, it was a very well thought out question. I suspect though that JPostma will be unable to see that the fact it is troublesome is a sign that his understanding of thermodynamics is decades out of date.
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JPostma at 01:24 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
"I'll end up using more energy to bring the frozen turkey to 60C than I will with a thawed turkey."
The cold turkey, of course, does not heat the oven. A colder turkey takes more time to heat, indeed, but neither a cold turkey nor a colder turkey heats up the oven.
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JPostma at 01:22 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
As words seem to creating only more confusion, perhaps the maths of heat flow will help? Heat flow in an ideal radiative situation is Q = sigma*(Tf^4 - Ti^4) where Tf is the temperature of the furnace and Ti is the temperature of the iron. Equilibrium is acheived when Q = 0, i.e. when heat flow equals zero, when there is no more heat flow. This means that the iron is not gaining or losing any energy but has constant energy. The end point is that Ti = Tf, the iron has come to the temperature supplied by the furnace. Of course, heat flow is only from the furnace into the iron. If the furnace was shut off and cooled faster than the iron, then the iron could heat the furnace somewhat and slow what would have otherwise been its cooling rate.
The question as to "when" the iron starts to radiate was what was precisely set up as the strawman. If you truly require me to answer "when" the iron starts to radiate, it is troublesome. But the answer is obvious, it has been stated, and the answer is specified directly in the heat flow equation here, and also by the simple understanding of heat flow and the ability to attain equilibrium.
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DSL at 01:16 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
Joe: "The cold iron does not heat the furnace."
The cold iron does not radiate? If it radiates, then the net exchange is simply altered. The exchange never stops. Does the temperature of the iron in the initial state matter for the temperature of the furnace? Yes, Joe. Yes it does. A frozen turkey in my oven will be more of a net gainer of energy than a thawed turkey. I'll end up using more energy to bring the frozen turkey to 60C than I will with a thawed turkey.
In other words, it's all relative. The thawed turkey has heated the oven relative to a condition with a frozen turkey.
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Dikran Marsupial at 01:14 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma wrote "I have stated in my first response, to quote: "the lump of iron radiates what is required of it"."
This is very obviously an evasive non-answer as it avoids specifically stating when the iron starts radiating (which was the question) and instead leaves the answer at best only implied. This sort of thing is not acceptable behaviour in a scientific discussion (as the point of the thought experiment was presumably to explicitly discuss the implications of your position).
"If the furnace somehow cooled down faster than the iron,"
you say "somehow" as if to suggest this is an unlikely scenario. It clearly isn't. The iron in the furnace (as we are discussing radiative transfer) is likely to be insulated (if only by a vacuum) from the body of the furnace, so if the body of the furnace is cooled after the iron has equilibriated with it, then of course the iron will cool more slowly.
You still have not unambiguously answered MA Roger's question (at what point would the iron start radiating, hint you need to specify a point in time). The fact that it is taking so long to answer such a simple question should be a cause of some concern to you.
"However, to be sure, the "exchange of energy" during the heating process is, to state precisely, an exchange of heat, which is into the iron only."
It seems that you do not understand the meaning of the word "exchange". There is no such thing as a unidirectional exchange. An exchange necessarily implies a transfer in both directions, although there may be a restriction on the net transfer.
Appologies to MA Roger for intruding into the discussion of his thought experiment; I shall drop out now.
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One Planet Only Forever at 01:09 AM on 17 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
foolonthehill,
I agree with naming and shaming those who deliberately fight against developing the collective understanding and actions that will lead to a sustainable better future for all. I also agree with charging the worst offenders with 'crimes against humanity'.
However, just naming them without effectively keeping them from succeeding, without ensuring them fail, could be just an interesting academic exercise. Actions that keep them from succeeding and then reporting their failed attempts would be beneficial.
The future of humanity needs those types to fail to succeed. The past history does not mean it is inevitable that those type of people and their 'success at the expense of others' must be accepted.
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JPostma at 01:02 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
"you have not said when the iron starts to radiate"
I have stated in my first response, to quote: "the lump of iron radiates what is required of it". This is of course how it can come to equilibrium, how the state of zero heat flow can be established.
If the furnace somehow cooled down faster than the iron, then the iron would suppy some heat to the furace and slow down the furnace's cooling from inside, but it would not raise the furnace's temperature, of course, and soon, both items would cool to ambient.
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JPostma at 00:59 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
DSL, such things are abvious, and indeed stated if not implied in my explanation of why the iron gets heated by the furnace.
However, to be sure, the "exchange of energy" during the heating process is, to state precisely, an exchange of heat, which is into the iron only. The cold iron does not heat the furnace. We have iron-ore smelters, and those workers do not shovel iron ore into the smelting furnace in order to make the furnace hotter - they shovel in coke, coal, or whatever, etc.
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Dikran Marsupial at 00:58 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma the question as posed was
Is there an instantaneous point in time when the iron that has now become hotter than the cooling furnace starts radiating as per standard physics and the furnace now cooler stops radiating? Or are you proposing a more gradual transformation from emitting to absorbing?
Note the question is about when the iron starts radiating. You still have not answered that question, as you have not said when the iron starts to radiate.
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JPostma at 00:55 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
You had assumed certain statements about non-emission from the iron, thus setting up a strawman.
Indeed, the iron can do nothing but be compelled (due to energy absorption) to rise in temperature to that being supplied by the furnace, at which point the temperature of the iron will stop rising, and come to equilibrium with the source furnace. Indeed there is a thermal gradient between the iron and the furnace and this is why the iron is induced, by heat flow, to rise in temperature until it equilibrates with the furnace. These are direct answers and I am sorry if you found them to be evasive.
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DSL at 00:53 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
Joe: "While at equilbirium, the iron is not losing energy - its energy is constant, or else it would be changing temperature. There is an equal exchange between emission and absorption at equilibrium."
An equal exchange: the iron is emitting and absorbing at equilibrium. It is losing energy and gaining energy at equilibrium. Do you also agree that there is an exchange of energy taking place during the heating process (but the net result is that the iron is a gainer)?
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Dikran Marsupial at 00:50 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma, the fact that you think that the thought experiment is a straw man may be because you do not understand the point of it. That doesn't mean the point doesn't exist, and a good scientist would just answer the question as posed, and not worry about giving a hostage to fortune (because if they were wrong, they would actively want to be corrected).
You are also wrong about the iron coming into equilibrium with the furnace, that is only true in the trivial case that they had both equilibriated to the ambient temperature, and is ignoring the fact there would be a thermal gradient until that had ocurred (neatly evading answering the question directly).
I'm sorry, I for one am not impressed by evasion. If you want to convince others, you will need to be willing to give direct, candid answers to direct questions.
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JPostma at 00:47 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
The iron and the furnace can come to equilibrium, at which point the iron has attained the temperature supplied by the furnace...assuming an idealized system of unit absorption and emission, etc. etc.
While at equilbirium, the iron is not losing energy - its energy is constant, or else it would be changing temperature. There is an equal exchange between emission and absorption at equilibrium.
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DSL at 00:42 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
Joe, does the iron lose any energy while the furnace is on? If so, how?
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JPostma at 00:40 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
Actually I pointed out that the thought experiment illogically assumed a certain condition, such as to set up a straw man. Thus the question can have no direct answer.
Subsequently however, I described the process of heating the iron inside the furnace, which I will repeat:
The lump of iron and the funace can come to equilibrium, the temerature of the iron being determined by the heating source, the furnace. If the furnace provides an internal isotropic temperature, then the iron will come to that temperature in due time. When the furnace is shut off, then the furnace will cool, and so will the iron.
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Dikran Marsupial at 00:36 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
It seems that JPostma replied to MA ROgers thought experiment while I was writing my post at 54; however I note that he did not actually answer the question posed, which was stated perfectly clearly:
Is there an instantaneous point in time when the iron that has now become hotter than the cooling furnace starts radiating as per standard physics and the furnace now cooler stops radiating? Or are you proposing a more gradual transformation from emitting to absorbing?
I also have a thought experiment that I would like to discuss with JPostma, but to avoid "dogpiling", I will wait until the discussion of MA Rogers' thought experiment is concluded.
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Dikran Marsupial at 00:33 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma I strongly recommend that you give a direct answer to MA Roger's thought experiment. Such thought experiments are an excellent way of demonstrating who is right, but I have noticed in discussions of climate change as distinct unwillingness to properly engage with clear thought experiments and they are all too often met with evasion and Gish gallops.
I somehow doubt you will be able to give an answer to this question; one of the real advantages of the modern statistical interpretation of thermodynamics is that no mechansim is needed to avoid photons being emitted from a cooler object in the direction of a warmer one. Ockams' razor suggests that if two theories explain the observations equally well, choose the simpler of the two. Statistical thermodynamics is clearly simpler than one in which any tansfer of energy from a cooler object to a warmer one is prohibited, and explains all observations equally well.
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JPostma at 00:32 AM on 17 July 2014Joseph E. Postma and the Greenhouse Effect
The lump of iron inside the furnace will not make the furnace hotter, indeed as the lump of iron radiates what is required of it.
The argument is of course a strawman, assuming certain illogicities in what is desired to interpret.
This is all very simple but for the expedient of the apparent requirement to discuss it - The lump of iron and the funace can come to equilibrium, the temerature of the iron being determined by the heating source, the furnace. If the furnace provides an internal isotropic temperature, then the iron will come to that temperature in due time. When the furnace is shut off, then the furnace will cool, and so will the iron.
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ubrew12 at 00:27 AM on 17 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
As we consider Murdoch's behavior, its useful to remember two things. 1)Unlike the Koch Brothers, he has no direct interest in the energy status quo. 2)This is not just a casual opinion. He forces this opinion onto almost every media outlet he owns. I'll bet there are few other subjects about which that is true. And, hence, the key to his puzzling behavior may be found in understanding what those other subjects are. What are the subjects Murdoch feels so strongly about that, evidence to the contrary, he directs the Wall Street Journal, etc, to broadcast his views rather than reality? And I suspect, if we did that, the commonality would be that these topics pose some kind of threat to Murdoch's views on free market capitalism. That he thinks of human progress as a kind of mad dash forward, kicking and clawing for preeminence, and 'the devil take the hindmost'. Capitalism, to him, is wild. Its Nature 'Red in tooth and claw', whereas Nature itself is just a canvas, an arena, where this race is conducted. Atop his pyramid, the supreme competitor shouts out to the Universe 'I win!', and absolutely, positively, does NOT want the Universe to say anything back. If you point to a world outside the arena, the Murdochs will laugh at you. The racetrack goes round and round and never ends: its infinite in all directions.
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MA Rodger at 23:50 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma @45.
I think your response demonstrates quite conclusively that my dreadful feeling was fully justified.Now this strange interpretation of the laws of thermdynamics you present - let's try to get more of a grasp of what you propose.
You seem happy to accept that a body will not emit any photons that would have been destined to be absorbed by a body with a higher temperature. So if I have two bodies, say a cold lump of iron and a hot furnace, I pop the iron in the furnace and the hot furnace will radiate photons at the iron as per standard physics. I assume you are signed up to that. But in your version the iron will radiate nothing whatsoever at the furnace. Not a single photon.
Time passes and the iron is soaked in the furnace and the furnace is then switched off, now quickly becoming cooler than the hot iron. So my question - Is there an instantaneous point in time when the iron that has now become hotter than the cooling furnace starts radiating as per standard physics and the furnace now cooler stops radiating? Or are you proposing a more gradual transformation from emitting to absorbing? (I assume here, for simplicity's sake, the surfaces of both bodies have each a uniform temperature as they warm/cool - so no warm spots/cool spots on the iron or on the walls of the furnace.) -
JPostma at 23:44 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
The problem is that much of what is believed about the greenhouse effect is a matter of interpretation. The intent is to interpret the data in the terms of making back-radiation/trapping responsible for the temperature found at the surface. However, these interpretations can be rejected out of hand immmediately, since there are other non-interpretatable factors which already lend to a higher surface temperature. Such as latent heat, which factually keeps the surface warmer than otherwise; and the natural lapse rate gradient, which as a matter of mathemtical fact will make the bottom of the atmosphere warmer than its average and more so than its top; and the actual real-time solar input, which is factually quite hot indeed, as the referenced hot-box experiments have demonstrated above, can directly induce temperatures well above 100C (of course which fills of the latent heat energy storage banks in liquid and vaporous water).
Thus, there are indeed material and factual objections which clearly relegate the back-radiation/trapping hypothesis as defunct, as there are actual factors which already lend to a higher bottom-of-atmosphere temperature.
"sufficient to emit greater energy at source than is recieve by incident radiation on the device"
That violates the first law of thermodynamics, and though I've refrained from engaging in the type of ad-hominem attack continually thrown my way, a statement like this really does expose scientific incompetency and a clutching of straws. I do apologize for having to make that remark, but alas, it couldn't be passed over in kindness, this time. Those preeminent experimentalists did not indeed interpret that their apparatus was magically producing more energy than received, ostensibly finding an exception to the 1st Law of thermodynamics. They would have laughed at that. What they found is that they could get sunlight to induce its maximum temperature on a plane, a temperature which is well above +100C. It is not an unexpected result.
Here for example is data (from this paper) which shows a measured solar flux higher than 1000 W/m^2.
Due to orbital eccentricity, the solar constant can actually be as high as ~1410 W/m^2, or +124C. That paper went on to show that the temperature induced at the surface was not actually bumped up to a higher temperature from back-radiation/trapping, and it also showed that the surface cools faster overnight than expected from a calculation without any back-radiation/trapping.
In any case, with all of these substantial errors and claims for the effects of back-radiation/trapping, which other physical effects are already at least partly if not entirely responsible for, it is simply sensible for me as a scientist to rework the problem without the usual interpretation and pre-interpretations typically applied, which of course as has been discussed, can logically be discarded outright in any case. Thanks for the discussion.
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Lionel A at 23:35 PM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
MA Rodger @#2
On the horrors of the average per capita contributions to AGW for individual countries, a new paper...
David J C MacKay included some charts of interest here in Chapter one, from page 12 of his workSustainable Energy - without the hot air
Notes on data sources are on page 21.
Thanks for the link to a newer study I am ckecking it out.
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Tom Curtis at 16:34 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma @46:
1)
"But with less than unit emissivity, of course you can get a higher temperature than the insolation."
If you mean emissivity across all bands of the spectrum, then no you cannot. For more interesting, however, is the case were you mean near perfect emissivity in visible light, but very low emissivity for IR radiation. In that case, yes you can get higher temperatures than insolation - but the principle by which you do so is that of the greenhouse effect. It turns out that you believe the greenhouse effect after all. At least, you believe it when the context is sufficiently obscure that people will probably not notice the inconsistency of your view with your main thesis.
2)
"Still, on a good day, insolation can be much higher than 1000 W/m^2."
Show me the evidence!
Remember that to account for the phenomenon, you have to show insolation 20% higher than 1000 W/m^2. To see how difficult that is, here are the cloud free hourly insolations at Albequque on the summer solistice (ie, when the Sun is closest to overhead at noon):
Note that the best values are found with 2-axis tracking, ie, with a mechanism that keeps the collector pointed directly at the Sun through the entire day. Further, note that the Albaquque is at 35 degrees North, which compares to the 34 degrees south of Cape Town where John Herschel made his observations.
3)
"These results are much too anecdotal and the factors which result in a final temperature equilibrium too unknown..."
First, written reporst by de Saussure and John Hershel (both eminent experimental scientists of their day) do not count as "anecdotal evidence".
Second, as to unknown factors, you are happy to quote botantical greenhouses as evidence despite a far greater number of unknown factors, including a known factor that they maximize glass surface area, and hence cooling by conduction through the glass surface, without any qualms. Your sudden concern for precission is very one sided.
Third, the facts about de Saussure's hot boxs were quoted in direct refutation of your claim that such hot boxes could not increase warmth above that of incident sunlight. In fact, they can, and demonstrably can. Regardless of the specific mechanism, your claim is shown to be false. The true claim is that such mechanisms (and no mechanism) can raise temperatures above the temperature of the energy source, ie, the Sun. But as nobody claims the greenhouse effect can, or does heat the Earth's surface to a temperature equivalent to that of the Sun's surface, that is irrelevant to the discussion.
4)
"As it is, aside from the red-herring of solar concentrators (i.e. magnifying glasses, focusing mirrors, etc), there are no numbers which have been presented which show higher-than-insolation temperatures being acheived by passive means."
First, solar concentrators are not a red herring. If you think so, you have misunderstood the 2nd law of thermodynamics.
Second, observations by two of the preeminent experimental scientists of their time have shown temperatures in solar hot boxes sufficient to emit greater energy at source than is recieve by incident radiation on the device. That is only possible because that temperature is less than the temperature of the incident photons, and because the energy leaving the device equals the energy entering the device. But it is possible, and has been observed, regardless of how much you want to ignore the data.
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Tom Curtis at 15:58 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma @47:
1) You have not shown that the simple model fails, ie, that it incorrectly predicts the situation it describes. You have only pointed out that it is too simplistic (flat surface, globally averages insolation, only on layer). Therefore you cannot infer that the more complex model which does not have those oversimplifications fails. To do so is to, yet again, pull your dishonest strawman argument of "refuting" the greenhouse effect by pointing out that an oversimplified model is oversimplified while studiously ignoring the more complex models that also show the greenhouse effect.
2) N2 and O2 are not trappers of radiant heat. More importantly, and more directly, with a detailed model of all energy transfers and relevant latent heats (as in a GCM), removing just the well mixed greenhouse gases increases the upward longwave radiation at the top of the atmosphere and reduces surface temperature. That is, if you include all the relevant physics within computational capacity, greenhouse gases modulate surface temperature by modulating upward TOA IR radiation. This is the third time you have ignored this simple fact. It may be that the model is wrong, but it is not shown to be wrong by only criticizing the single layer model. In fact, by retaining your straw man focus you make clearer and clearer the dishonest nature of your argument.
3) We do in fact know what the global mean surface temperature is to a very good approximation (+/- 0.1 C). More importantly, we know the surface temperature was at various points of observations when comparisons were made between model and observed TOA upward IR radiation (see first panel):
4)
"In the argument above with the red and green areas in the plot, the red curve assumes a perfect blackbody of emission at 286K."
Actually, comparing the upward radiation for 299.7 K at 0 km altitude on modtran (as used in generating the red and green figure) shows the model to have an assumed surface emissivity of 0.9123. If we compare that to the known emissivities of varios surfaces we see that that is a significant underestimate of normal surface emissivities - ie, the model understates the size of the greenhouse effect (graph, and others, from Science of Doom):
5)
"Thus, the arguments presented there, while quite good and the attempt at proper science is good, is ultimately based on supposition and "if we assumes", etc."
I think it is plane to any reader that I am the one actually presenting evidence here. You are the one falling all over yourself to thoughtlessly dismiss that evidence without giving any consideration to what it in fact means.
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foolonthehill at 14:36 PM on 16 July 2014Deep Decarbonization Pathways Project (DDPP) Presents Interim Report to UN Secretary-General Ban Ki-Moon
Wili
'I just want to get it down to the size where we can drown it in a bathtub!'
The recommended way to lose a lot of weight is little by little, over a long period of time. Genuine lifestyle changes are far more successful than stomach stapling at keeping that weight loss in the long term.
Take your time drawing that bath ;-)
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foolonthehill at 14:18 PM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
One Planet
There will always be bad people like Murdoch. Someone, somewhere will follow in his footsteps. Fantastic wealth and power are attractive. I don't think his failure will set an example that will deter such people.
History is populated by failed despots and yet still they continue to pop up. They all think they are infallible. If Murdoch were to fail they would say that he wasn't ruthless enough.
I do think that there is something that should be done about recording their contribution to our problems.
The climate change deniers are in the process of realising their stupidity and failure. Now they will switch their tactics to trying to control our response to the threat of climate change. This response will favour their subsequent quest for more power.
This is where we need to be vociferous in naming and shaming them. The politicians who denied climate change and installed policies that contributed to it, must be held up to scrutiny. The Internet is a poor place to achieve this - look at how US politicians have changed their Wikipedia entries when it is convenient.
The internet may not be with us in 100 years time. Climate change will be.
Something immutable needs to hold the record. The prior antics of those such as Murdoch, Palin, and the Kochs should be recorded. Those in the media that took the King's Shilling should also be noted - they have assisted in misleading the public.
Their memory will be subject to the opprobrium of the people who are suffering in centuries to come. This is how they should be remembered.
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One Planet Only Forever at 14:15 PM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
Sam,
DSL has provided a lot of information regarding your question. Maybe this will also help you better understand what you see in the HadCRUT and GISSTEMP data between 1910 ad 1940.
The Wikipedia information on "Carbon Doioxide in the Earth's Atmosphere" includes a chart of CO2 levels since 1000 AD. The concentration of CO2 was about 280 ppm from 1000 AD through to 1750 AD. Then a noticeable increase of CO2 levels starts to occur. By 1900 the CO2 concentration was passing 300 ppm.
So there were CO2 increases most likely due to human activity that partially explains why global temperatures were increasing between 1910 and 1940. However, as DSL mentioned there are many other transient influences. The combined effect of all those influences created the 1910 to 1940 trend you see.
A way to see the trend is to look at the 5 year rolling average of the GISSTEMP data. The rate of increase during the period you are focusing on may look similar to the increase since 1980. However, if you look at all the data you will see that 1910 was a significant temporary low point in the records and 1940 was a significant temporary high point in the record. So focusing on the trend of that period could be referred to as cherry-picking.
Just looking at the 5 year average line you can appreciate that lines of longer averages would have a higher value in 1910 and a lower value in 1940, reducing the trend in this period. You will also see that the data since 1980 has only been up with some level bits along the way including the well explained reduced rate of increase in the data since the 1997/98 super El Nino spike. And the line of longer averages would continue to sloping up through those level bits, including sloping up through the period since 1998.
I hope that helps you better understand what you are seeing between 1910 and 1940.
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DSL at 14:05 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
Joe, you have a serious penchant for strawmen. We know there's downwelling longwave radiation because it has been directly measured from surface and has been found to fit pretty well with theory/model-based expectations.
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wili at 13:52 PM on 16 July 2014Deep Decarbonization Pathways Project (DDPP) Presents Interim Report to UN Secretary-General Ban Ki-Moon
To be clear, I don't want to destroy the global economy immediately, I just want to get it down to the size where we can drown it in a bathtub! ;-P
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JPostma at 13:39 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
As a matter of logic, if you have a more complex model created based upon the suppositions induced from a simpler erroneous model, it doesn't save the more complex model. Creating more complex models looking for a radiative back-heating/trapping effect does not prove a radiative back-heating/trapping effect. Besides, when doing more proper physics and science and accounting for the other real phenomena at work, since the supposed back-radiation/trapping is not the only thing occuring, N2 and O2 are already heat trappers due to their low emissivity, and latent heat from liquid and vaporous water already store and release heat at the surface as well. Thus, any argument which posits radiation trapping/back-radiation as the cause of surface temperature must be discarded outright, for pretending to do everything which it manifestly doesn't.
In the argument above with the red and green areas in the plot, the red curve assumes a perfect blackbody of emission at 286K. The surface probably doesn't emit like a perfect blackbody, but more importantly, the surface temperature is not actually 286K - the surface temperature is not actually known at all. The 286K only corresponds to the air-temperature at 1.5m from a haphazardly distributed set of measurement stations on land. We don't actually know what the actual surface temperature is. Thus, the arguments presented there, while quite good and the attempt at proper science is good, is ultimately based on supposition and "if we assumes", etc.
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One Planet Only Forever at 13:24 PM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
foolonthehill,
My focus is on striving to develop a sustainable better future for everyone. So Mr. Murdoch is just one of many trouble-makers to be recognised for the unacceptability of the actions they pursue. The "success" of each of those unacceptable people provides an unsavory but appealing example others may be tempted to try to follow.
Developing a sustainable future for all life on this amazing planet is the only viable future for humanity. And it requires the likes of Murdoch to fail to succeed. Even if they do not seem to have many more damaging years left, their example will outlive them. The example of their demise because of their unacceptable attitude and actions is what needs to be seen.
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JPostma at 13:20 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
"Later, William Herschell designed a de Saussure hotbox that achieved a temperature of 240 Farenheit in South Africa, a temperature generating black body radiation of 1294 W/m^2 of thermal radiation. That is significantly greater than the 1000 W/m^2 solar insolation at ground level (ie, after absorption and scattering as it passes through the atmosphere). (De Saussure's 110 centigrade represents a black body radiation of 1222 W/m^2.)"
But with less than unit emissivity, of course you can get a higher temperature than the insolation. Still, on a good day, insolation can be much higher than 1000 W/m^2. These results are much too anecdotal and the factors which result in a final temperature equilibrium too unknown, such as emissivity, the albedo of the collecting box, what the actual insolation was, etc. The results as they are are extremely close to simple direct heating with hot-air trapping.
"Because the individual photons from sunlight come from the Sun's surface, in principle it would be possible to heat a surface to the temperature of the Sun's surface with no violation of the 2nd law. In practise, we can never achieve perfect efficiency and so that is not possible. Never the less, solar concentrators can achieve temperatures in excess of 3,200 centigrade despite being subject to the same thermodynamic limits."
That is done by concentrating the incoming solar input from a large collecting area and focussing it into a much smaller absorption area. Nothing to do with the greenhouse effect or backradiation/radiation trapping.
" the temperature rises to the point at which the incident heat is exactly balanced by the dissipated heat"
The incident heat is of course given only by the sun. This is why in those experiments you reference, a higher temperature than the solar input was not actually really observed.
Indeed, an empirical test should be done on these matters, accounting for all variables. As it is, aside from the red-herring of solar concentrators (i.e. magnifying glasses, focusing mirrors, etc), there are no numbers which have been presented which show higher-than-insolation temperatures being acheived by passive means.
"Never-the-less, the known facts for de Saussure's hotboxes show with very high probability that the radiant insulation is the most important factor were multiple panels prevent carrying heat of by conduction through a single glass panel."
Indeed, the glass lids prevent the convection of hot air and replacement of cool air from elsewhere.
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JPostma at 13:04 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
"I have this dreadful feeling - you understand relativity less well than even your purile inderstanding of thermodynamics."
Simply apply the Lorentz transformations with v = c, and see what the results say.
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Tom Curtis at 12:51 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma @26, as a matter of logic, if you have two models both producing the same effect, then one feature which is present in one model but absent in another cannot be the cause of the effect. Thus, if you have a model with a single layer, and a flat surface, and a second model with 40 layers, and with 10,368 cells, cells per layer, each arranged so that together they are a close approximation of a sphere; and if in the second model the insolation at the top of the atmosphere matches that from the Sun, and both show the greenhouse effect, then the flat surface or the reduced insolation, or the single layer in the first model are not necessary to produce the greenhouse effect. On the contrary, the greenhouse effect can be produced with a spherical Earth, with full insolation and geometry, and with multiple layers. In this situation, focussing exclusively on the simple model in order to "disprove" the existence of the greenhouse effect, and claiming it to be disproved because the simple model has unphysical features that are not present in the complex model shows either rank ignorance or complete dishonesty.
I have already linked to Lacis et al (2010), who show the effect of removing the well mixed greenhouse gases from the atmosphere:
As can be easilly seen, the first effect is to increase the upward Top of Atmosphere (TOA) radiation by 60%. Planetary albedo only increases by 40% (from 0.3 to 0.42), so there is a 20% increase in the upward TOA long wave radiation. That is the increase which is predicted by the theory of the greenhouse effect, and it occurs as predicted. Concurrent with that change, temperatures drop by 35 degrees C. That is of the same order of the consequence of the greenhouse effect as predicted by zero dimensional models. It differs slightly because, first, the zero dimensional models do not include any change in albedo, and second, because some greenhouse warming from water vapour is retained.
So, the more complex model clearly shows the greenhouse effect, and clearly shows it to have a large impact on surface temperatures.
In response to that you say:
"It doesn't matter if you add more layers or have higher dimeniosnality models. The postulate of the radiative greenhouse effect still has no basis. And we have been looking through the IPCC models, and there is no actual greenhouse effect in them, anywhere. Neither Spencer nor anyone else can identify it and say where in the models it is, or how it originates. What they will do however, is always refer back to the 1-D models! It's kinda crazy."
However, that is transparently, and entirely mistaken. Adding extra dimensions (geometry) does matter because it makes the models more realistic, while retaining a greenhouse effect. So also with adding more layers. More importantly, the IPCC models clearly have an identifiable greenhouse effect as shown by Lacis et al. I cannot speak for Spencer, but the notion that Lacis and co-authors cannot identify the greenhouse effect in their models is laughable.
What is worse, I have, in my previous post clearly identified the greenhouse effect in actual observations. I also linked to a post of mine which clearly explains the greenhouse effect, which you have clearly ignored. For your convenience, I will quote from it:
"Using Modtran, I determined the energy output looking downwards from an altitutude of 70 kilometers using the US Standard Atmosphere (1). The result can be seen on the following graph as the green shaded area. I repeated the model run, but this time with the altitude set at 0 km. The result is shown by the outer curve defining the red area in the graph below. That means that the red area itself, which is the upwards radiation from the surface minus the upward radiation to space, is the reduction in energy radiated to space because of the presence of Infra-Red absorbing molecules in the atmosphere. That is, it is the greenhouse effect."
If that is not clear enough, the greenhouse effect is the difference between the upward IR radiation at ground level and the upward IR radiation at the top of the atmosphere. That difference can be identified easilly in any GCM. Further, no model encoding actual physics confirmed in laboratories (such as the Stefan-Boltzmann law) can show the difference without having a ground temperature warmer than the effective temperature (ie, the temperature predicted from insolation). The reduced upward radiation causes the increased surface temperature.
At this point, there has been no lack of clarity on my part. If you come back and say "yes, but one d model", you will clearly show that you are dishonestly using a strawman argument. If you cannot show your argument true using the 42 layer, 10,368 cell, spherical geometry GISS Model E2 used by Lacis et al (2010), you are merely showing your argument depends entirely on using simplistic models only used for teaching as we have said all along.
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foolonthehill at 12:27 PM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
Rupert is very rich. Rupert is very powerful. Rupert is very old.
Concentrate on the latter.
How many more years at the helm? 5? Maybe 10? Look to who will succeed him at News Corp. Will they have the same power and influence? I doubt it.
Love him or hate him, Rupert is a force of nature but his place in the sun is due to be vacated. His heirs are unlikely to have the same opinions or killer instinct as he did. Their sibling rivalry is already stuff of legend. The kingdom will be divided.
A local farmer told me that he had a nasty feud with a neighbour for many years. After a fruitless struggle to resolve many issues he came to the following conclusion -
There are some awful people who will never see reason. The way to triumph is simply to outlive them. They will be replaced by someone else and you won't have wasted your life fighting.
The end is nigh. In the words of Rupert's good pal Lady Thatcher -
"Rejoice"
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Tom Curtis at 12:04 PM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma @40, the botanist's greenhouse is not the "original greenhouse" to which analogy was made with regard to the greenhouse effect. Rather, in the very first postulation of a greenhouse effect, by Jean-Baptiste Fourier in 1827, an analogy was drawn with Horace Bénédicte de Saussure's hotboxes:
"It is difficult to know just to what extent the atmosphere affects the mean temperature of the globe, and here the guidance of rigorous mathematical theory ceases. One is indebted to the celebrated explorer M. de Saussure for an experiment which appears to be well suited to clarifying this question. The experiment consists of exposing a vessel covered by one or more sheets of highly
transparent glass (placed at some distance from each other) to the rays of the Sun. The interior of the vessel is covered with an thick layer of blackened cork, suited to absorb and retain the heat. The heated air is contained in all parts of the apparatus, either in the interior of the box or in each gap between two plates of glass. Thermometers placed in this vessel and in the spaces between
the plates register the degree of heat acquired in these cavities. This instrument was exposed to the Sun at or near noontime, and it has been observed, in various experiments, that the thermometer in the vessel raises to 70o, 80o, 100o, 110o or even higher (octogesimal division). Thermometers placed within the gaps between the sheets of glass indicate a much lower degree of heat acquired, decreasing steadily from the bottom of the box up to the top gap."(My emphasis)
The fact that the temperature increase became greater with additional panels of glass refutes the simplistic notion that the effect is entirely the consequence of preventing heated air being carried of by the wind. Nor is it likely due to the insulating properties of the glass, as glass is a good thermal conductor.
Later, William Herschell designed a de Saussure hotbox that achieved a temperature of 240 Farenheit in South Africa, a temperature generating black body radiation of 1294 W/m^2 of thermal radiation. That is significantly greater than the 1000 W/m^2 solar insolation at ground level (ie, after absorption and scattering as it passes through the atmosphere). (De Saussure's 110 centigrade represents a black body radiation of 1222 W/m^2.)
There are in fact thermodynamic limits to how warm the greenhouse effect (or other methods of retarding energy loss) can make warm an object. That limit is set, however, by the balance of energy in to energy out (first law of thermodynamics); and by the entropy of individual photons (second law of thermodynamics). Because the individual photons from sunlight come from the Sun's surface, in principle it would be possible to heat a surface to the temperature of the Sun's surface with no violation of the 2nd law. In practise, we can never achieve perfect efficiency and so that is not possible. Never the less, solar concentrators can achieve temperatures in excess of 3,200 centigrade despite being subject to the same thermodynamic limits.
Returning to de Saussure's hotboxes, Fourier noted:
"The theory of this instrument is easy to formulate. It suffices to remark that: (1) the heat acquired is concentrated, because it is not dissipated immediately by exchange of air with the surroundings; (2) the heat emanated by the Sun has properties different from those of dark heat. The rays of this star are for the most part transmitted through the glass without attenuation and reach the
bottom of the box. They heat the air and the surfaces which contain it: the heat communicated in this way ceases to be luminous, and takes on the properties of dark radiant heat. In this state, the heat cannot freely traverse the layers of glass which cover the vessel; it accumulates more and more in the cavity enclosed by materials which conduct heat poorly, and the temperature rises to the point
at which the incident heat is exactly balanced by the dissipated heat."So, from the first analogy, the two methods by which the hotboxes (and greenhouses) work are clearly noted; and no claim is made as to which is the stronger. That Fourier's care in explanation was lost by later popularizers has no bearing on the physics involved.
It would in fact be interesting to properly test the actual existence of the greenhouse effect in a de Saussure hotbox more rigourously than has been done previously. That would involve constructing two hotboxes, one using glass for the panels, and one using another material, equally transparent to the visible, transparent to IR, and equally conductive of heat. That is because a major form of heat loss in hotboxes (particularly of single panels) is from conduction to the external air from the glass pane (glass being a good conductor). It is not clear whether the superior conductivity of glass relative to acrylic allows the escape of more heat than is retained by the IR opaqueness of glass, and whether it does or not may well depend on conditions. To avoid this issue, the hotboxes need to be placed in a vacuum so that radiation is the only method by which heat can escape. You also need to screen both boxes from the source of radiant heat with a panel of glass to ensure that both have the same radiant energy absorbed at the bottom of the box. I am unaware of any attempt to test the theory that is rigourous to that extent. Never-the-less, the known facts for de Saussure's hotboxes show with very high probability that the radiant insulation is the most important factor were multiple panels prevent carrying heat of by conduction through a single glass panel.
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Lloyd Flack at 11:15 AM on 16 July 2014Rupert Murdoch doesn't understand climate change basics, and that's a problem
Paul D @20
I think it is actually
3. He does not believe there is such a thing as expertise and integrity in this matter. He has little ability to recognize integrity since he does not try to fight his biases and expects that noone else will do so either.
In journalism he has been a muck raker with an anti-authoritarian pose. His main target has been traditional conservatism with its respect for authority and responsibility not the left. He is as far as I can see a very rich bogan trying to tear down anything that he feels might look down on him.
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Rob Honeycutt at 10:00 AM on 16 July 2014Deep Decarbonization Pathways Project (DDPP) Presents Interim Report to UN Secretary-General Ban Ki-Moon
I'll qualify the statement a bit. I'm very optimistic that we aren't going to end up on the worst path. I believe that solutions are going to come fast and furious as soon as we really get pricing on carbon emissions.
We are undoubtedly going to end up doing both mitigation and adaptation. Hopefully we'll be doing more of the former so that we have to do less of the latter.
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foolonthehill at 09:44 AM on 16 July 2014Deep Decarbonization Pathways Project (DDPP) Presents Interim Report to UN Secretary-General Ban Ki-Moon
Rob
'I'm actually very optimistic about the future'
Not sure if I would go quite that far - maybe I'm just a pessimist who is prepared for the hard yards...
Discussions such as this are what we really need to concentrate on if we are to create positive change. The personal choices we make are important. I wonder if there is a place for a such discussions on a more regular basis on this site.
I delight in the to and fro of the arguments in various threads on SKS.Despite having a degree that is science based, the detail in the posts and comments on SKS can be necessarily quite esoteric. Long may they remain. However - many lay people come here for information and perhaps there could be a section that is dedicated to the possible changes that individuals can make in their personal lives that lead to solutions to our predicament?
Many years ago there was a TV program called Hypotheticals where solutions to problems were discussed with variables being added along the way to highlight how we have to account for them. Is there a place for something like this in relation to personal climate change action?
In regards to our present discussion of building replacement versus refurbishment, I have a personal housing dilemma that has various possible solutions. Would there be a beneficial educational opportunity to discuss such possibilities on a separate thread/section on SKS? Maybe such a forum exists online already? If so, does it have the same breadth of knowledge that the SKS contributors possess?
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John Hartz at 09:41 AM on 16 July 20142014 SkS Weekly Digest #28
@ZincKidd: For a fairly detailed and straight-forward report on what transpired at the Heartland conference in Las Vegas, check out:
In Las Vegas, Climate Change Deniers Regroup, Vow to Keep Doubt Alive by Abe Streep, BloombergBusinessweek, July 10, 2014
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ZincKidd at 09:15 AM on 16 July 20142014 SkS Weekly Digest #28
Has there been any interesting coMmentary on ICCC9? It seems rather funny, really, that there is an organization and conference devoted to something that, as far as they are concerned, doesn't even exist...
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scaddenp at 08:11 AM on 16 July 2014Joseph E. Postma and the Greenhouse Effect
JPostma, do you agree:
1/ That despite your difficulties with the layer model as a teaching tool, climate scientists do not have a such problem as evidenced by eg Smith 2008 and by the codes.
2/ In a botanical greenhouse, the primary effect is convection which massively overpowers any radiative effect. The Greenhouse Effect is inaptly named but that doesnt make it wrong.
3/ The most important test of the model is whether the numbers it produces match what you observe in empirical testing. This is after all how the model informs climate science.
4/ The actual radiative codes used (Hitran) predict the radiative power and spectra for both incoming and outgoing radiation to a remarkable degree of accuracy.
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