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Post by poitsplace on Mar 3, 2009 15:05:09 GMT
poitspace, If you cannot understand how a water vapour feedback can cause warming without causing "runaway" warming, then that is a shortcoming of your understanding. If you need it spelt out, suppose 1C warming leads to 2/3C warming, which leads to (2/3) * (2/3)C warming etc. This tops out at about 3C warming overall. In engineering jargon, I don't think it is technically a "positive feedback", but since when did use of the wrong term become a scientific falsification! My problem is when TOTAL feedbacks go near or beyond 1 to 1 as many have suggested. If all the feedbacks go past 1 to 1 ratios they're capable of driving themselves...period. Another problem is that (as I've stated before) most of the feedbacks are probably strongly negative by now. One only needs to look at the peaks and valleys of the temperature record to realize something about the current configuration of the earth must in fact be holding things BACK. The CO2 sure as heck isn't doing it. The temperature fluctuates up and down for 600-2000 years sometimes before CO2 has any significant reaction. Ice albedo and water vapor feedback could play a role but it appears their best attenuation is of the COLD, not the warm periods...and this makes perfect sense. The arctic ice cap gets little sunlight and is actually quite close to the albedo of the open ocean at the angles at which the light hits. Likewise at the incredible concentrations of water in the air over most of the surface, there's little increase in captured energy for increases in humidity. The only thing water seems to do well is capture the energy and release it later as it recondenses...basically warming the nights. No, the next quasi-stable state up appears to be total deglaciation of the antarctic BUT...you've got a problem, the feedbacks are almost certainly holding temperatures back. All these wild assumptions to the contrary (used in computer models) show no actual affect in the real world. Yes, the ice melts. Yes, the humidity increases. Yes, methane is released...but temperatures simply do not follow the models. Well, the newer ones do but that's actually because they're forced to conform to reality. The models are just wrong and it's because we don't understand what we're modeling. Temperatures would have to increase at current rates (but against the feedbacks) for 600-800 years to reach the next strongly positive feedback state. in a later post you said Thermal radiation is not the same thing. In those cases it didn't just receive the EXACT amount of energy necessary to reemit. The electrons aren't being excited by physical interactions with agitated neighbors, they're being directly stimulated by the specific frequencies at which they absorb/emit...and at energy levels that in no way destabilize the molecule (powerful UV on the other hand often just blows the oxygen molecules apart...which means much of it gets converted straight into heat). Anyway, my point here is that you're confusing two entirely different types of interaction.
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Post by donmartin on Mar 3, 2009 17:30:41 GMT
Steve: I couldn't bring the "Classic Articles: up on my computer. Is there another way or article?
Thank you
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Post by steve on Mar 3, 2009 18:09:13 GMT
poitspace, If you cannot understand how a water vapour feedback can cause warming without causing "runaway" warming, then that is a shortcoming of your understanding. If you need it spelt out, suppose 1C warming leads to 2/3C warming, which leads to (2/3) * (2/3)C warming etc. This tops out at about 3C warming overall. In engineering jargon, I don't think it is technically a "positive feedback", but since when did use of the wrong term become a scientific falsification! My problem is when TOTAL feedbacks go near or beyond 1 to 1 as many have suggested. If all the feedbacks go past 1 to 1 ratios they're capable of driving themselves...period. Noone serious is suggesting such a scenario for the water vapour feedback (at least for half a billion years or so). Occasionally "runaway warming" is used to speculate about onsets ("tipping points") of strong positive feedback such as mass methane releases, which runaway till all the methane is released. But these would stop when all the methane is exhausted. I don't think the evidence is there to support such a cycle in the record. There have been cycles of 1500 years or so during colder times, but not recently. Kirchoff's law was long before the invention of the electron! The upshot of Kirchoff's law is that a good absorber of energy is a good emitter of energy, as absorption and emission will balance out when in local thermal equilibrium. It says nothing about the mechanism of the emission, which for thermal absorption and emission from CO2 is not an ionising process. In this case the CO2 is excited (to a more energetic vibrational state) by radiation or interaction with other molecules, and is deexcited by interaction with other molecules or emission of infrared. When you irradiate a gas containing CO2, eventually (other things being equal) a balance will be reached such that the absorption of IR will approximately match the emission.
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Post by steve on Mar 3, 2009 18:12:37 GMT
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Post by poitsplace on Mar 3, 2009 19:29:55 GMT
My problem is when TOTAL feedbacks go near or beyond 1 to 1 as many have suggested. If all the feedbacks go past 1 to 1 ratios they're capable of driving themselves...period. Noone serious is suggesting such a scenario for the water vapour feedback (at least for half a billion years or so). Occasionally "runaway warming" is used to speculate about onsets ("tipping points") of strong positive feedback such as mass methane releases, which runaway till all the methane is released. But these would stop when all the methane is exhausted. I don't think the evidence is there to support such a cycle in the record. There have been cycles of 1500 years or so during colder times, but not recently. I didn't mean there was a cycle, I meant the cycle seem to be what drives CO2 but it was simply delayed by 600 years (degassing of oceans) to several thousand years (absorption by the oceans). In the past temperatures would take off while CO2 levels lagged behind and the temperatures would drop while CO2 remained high for much longer. This should of course be expected since degassing is a volumetric process and absorption essentially only occurs at the surface.
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Post by donmartin on Mar 3, 2009 21:06:49 GMT
Steve, a difficulty I might see in John Tyndall's experiment is that he was measuring absolute "absorption", and therefore would the fact that his experimente was conducted in a closed environment make his outcome and theory non-analogous and perhaps unrelated to the Earth's atmosphere which is an open environment. In other words, had he conducted the respective experiment in an open environment, would the outcome not have been decreased heat content in the resulting volume although the temperature of the (atoms and molecules) would have increased?
Just asking
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Post by socold on Mar 4, 2009 8:29:47 GMT
Let me put this in a simple way...unless your models can explain why the numerous warm/cool periods occurred in the past...you have ZERO VALIDATION of the models. My post was a reply to your earlier post. Your post made two arguments: 1) much of the 20th century warming was due to coming out of the little ice age 2) the feedbacks in models would be enough to sustain themselves if true I disagreed with both points and laid out why in my post. Can I assume you are still pushing these arguments or have you abandoned them? Your post doesn't make it clear.
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Post by poitsplace on Mar 4, 2009 10:15:12 GMT
Let me put this in a simple way...unless your models can explain why the numerous warm/cool periods occurred in the past...you have ZERO VALIDATION of the models. My post was a reply to your earlier post. Your post made two arguments: 1) much of the 20th century warming was due to coming out of the little ice age 2) the feedbacks in models would be enough to sustain themselves if true I disagreed with both points and laid out why in my post. Can I assume you are still pushing these arguments or have you abandoned them? Your post doesn't make it clear. I'd still doubt the feedbacks would even be that much because we're quite obviously fluctuating between two semi-stable climate states and being near the high end the feedbacks for warming SHOULD be strongly negative. but ummm...as to your first point, if much of the warming was natural and the rate is so low...it seems to me that you've basically tossed out the only thing you had to complain about. Yeah, CO2 is causing horrible warming, well most of it is perfectly natural but between feedbacks (which would have been working all this time but obviously can't have been at the rates you state) and CO2 (oops it's not responsible for most of what's been observed) we'll have horrible, horrible warming. *sigh* your explanation makes it sound like the actual anthropogenic global warming has been minute...something I agree with. If the warming is below the .13C per decade but most of it was natural then there's no reason to worry about CO2 at all. We're basically back to the initial problem...you're saying it's all but a certainty that CO2 is causing incredible warming that's quite simply not been observed. Did we just miss going into the ice age? Would you be complaining about such a missed opportunity to freeze to death? Honestly that's about the only AGW hypothesis that makes ANY sense given the data we have.
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Post by steve on Mar 4, 2009 12:49:28 GMT
Steve, a difficulty I might see in John Tyndall's experiment is that he was measuring absolute "absorption", and therefore would the fact that his experimente was conducted in a closed environment make his outcome and theory non-analogous and perhaps unrelated to the Earth's atmosphere which is an open environment. In other words, had he conducted the respective experiment in an open environment, would the outcome not have been decreased heat content in the resulting volume although the temperature of the (atoms and molecules) would have increased? Just asking Donmartin, The experiment answers the question you had about whether the greenhouse gas absorption results in a warming of the gas as a whole. In the open environment the net change in heat content would be about the same (conservation of energy) but it would be more widely distributed (by winds, convection, diffusion etc.).
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Post by steve on Mar 4, 2009 12:58:29 GMT
My post was a reply to your earlier post. Your post made two arguments: 1) much of the 20th century warming was due to coming out of the little ice age 2) the feedbacks in models would be enough to sustain themselves if true I disagreed with both points and laid out why in my post. Can I assume you are still pushing these arguments or have you abandoned them? Your post doesn't make it clear. I'd still doubt the feedbacks would even be that much because we're quite obviously fluctuating between two semi-stable climate states and being near the high end the feedbacks for warming SHOULD be strongly negative. This doesn't follow as logically as you think. If, say, we are fluctuating between glacial and interglacial, then *maybe* the "warm" end is constrained by the fact that once most of the ice goes, the ice albedo feedback is reduced; that would be an argument for an upper level for the warming. But it doesn't follow that *all* the causes of positive feedback are small or negative. Is a rise of less than a degree "incredible warming"? Would such a rise have prevented a descent into an ice age by now? I think the answer is no and no. So we're back to whether the approx 1C rise is significantly due to CO2 and whether the subsequent rise due to further CO2 might provide as little as 1C or as much as 4C of further warming.
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Post by donmartin on Mar 6, 2009 19:13:57 GMT
Just a question. Were a hydrogen atom the size of Earth, what would be the distance to the next hydrogen atom, also the size of the Earth?
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Post by kiwistonewall on Mar 13, 2009 12:18:44 GMT
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Post by hilbert on Mar 13, 2009 12:56:57 GMT
Just a question. Were a hydrogen atom the size of Earth, what would be the distance to the next hydrogen atom, also the size of the Earth? I think that it worked out to be about 20 or so earth radii (diameters?) away for a gas at STP (standard temperature and pressure). That would be if the air at sea level were all Hydrogen. So, not very far apart, really.
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Post by nautonnier on Mar 13, 2009 21:03:07 GMT
Indeed it does - Perhaps SoCold and Steve should review the paper. Especially SoCold who keeps telling people to 'run the numbers through the physics' I have worked with TU Braunschweig - they are _very_ good and in the heart of the German Research district.
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Post by kiwistonewall on Mar 14, 2009 1:19:01 GMT
For those who don't want to read that paper (see my post above) here is the summary conclusion:
Physicist's Summary A thorough discussion of the planetary heat transfer problem in the framework of theoretical physics and engineering thermodynamics leads to the following results: 1. There are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effect, which explains the relevant physical phenomena. The terms "greenhouse effect" and "greenhouse gases" are deliberate misnomers. 2. There are no calculations to determinate an average surface temperature of a planet with or without an atmosphere, with or without rotation, with or without infrared light absorbing gases. The frequently mentioned difference of 33C for the fictitious greenhouse effect of the atmosphere is therefore a meaningless number. 3. Any radiation balance for the average radiant flux is completely irrelevant for the determination of the ground level air temperatures and thus for the average value as well. 4. Average temperature values cannot be identified with the fourth root of average values of the absolute temperature's fourth power. 5. Radiation and heat flows do not determine the temperature distributions and their average values. 6. Re-emission is not reflection and can in no way heat up the ground-level air against the actual heat flow without mechanical work. 7. The temperature rises in the climate model computations are made plausible by a perpetuum mobile of the second kind. This is possible by setting the thermal conductivity in the atmospheric models to zero, an unphysical assumption. It would be no longer a perpetuum mobile of the second kind, if the \average" fictitious radiation balance, which has no physical justification anyway, was given up. 8. After Schack 1972 water vapor is responsible for most of the absorption of the infrared radiation in the Earth's atmosphere. The wavelength of the part of radiation, which is absorbed by carbon dioxide is only a small part of the full infrared spectrum and does not change considerably by raising its partial pressure. Falsification Of The Atmospheric CO2 Greenhouse Effects : : : 93 9. Infrared absorption does not imply "backwarming". Rather it may lead to a drop of the temperature of the illuminated surface. 10. In radiation transport models with the assumption of local thermal equilibrium, it is assumed that the absorbed radiation is transformed into the thermal movement of all gas molecules. There is no increased selective re-emission of infrared radiation at the low temperatures of the Earth's atmosphere. 11. In climate models, planetary or astrophysical mechanisms are not accounted for properly. The time dependency of the gravity acceleration by the Moon and the Sun (high tide and low tide) and the local geographic situation, which is important for the local climate, cannot be taken into account. 12. Detection and attribution studies, predictions from computer models in chaotic systems, and the concept of scenario analysis lie outside the framework of exact sciences, in particular theoretical physics. 13. The choice of an appropriate discretization method and the definition of appropriate dynamical constraints (flux control) having become a part of computer modelling is nothing but another form of data curve fitting. The mathematical physicist v. Neumann once said to his young collaborators: \If you allow me four free parameters I can build a mathematical model that describes exactly everything that an elephant can do. If you allow me a fith free parameter, the model I build will forecast that the elephant will fly." (cf. Ref. [185].) 14. Higher derivative operators (e.g. the Laplacian) can never be represented on grids with wide meshes. Therefore a description of heat conduction in global computer models is impossible. The heat conduction equation is not and cannot properly be represented on grids with wide meshes. 15. Computer models of higher dimensional chaotic systems, best described by non-linear partial differential equations (i.e. Navier-Stokes equations), fundamentally differ from calculations where perturbation theory is applicable and successive improvements of the predictions - by raising the computing power - are possible. At best, these computer models may be regarded as a heuristic game. 16. Climatology misinterprets unpredictability of chaos known as butterfly phenomenon as another threat to the health of the Earth. In other words: Already the natural greenhouse effect is a myth beyond physical reality.
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