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Post by steve on Jul 17, 2009 16:50:26 GMT
Icefisher, have you started your Friday evening early?
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Post by jimcripwell on Jul 17, 2009 17:29:54 GMT
steve writes "You would say this opens one up to the Kelvin "fallacy"."
No I would not. In physics, knowledge is based on things that are measured; period. If you dont understand this, then you dont understand physics. A makes a measurment and publishes his findings. B replicates the measurement, etc. and we have a sound basis on which to theorise what the measurements mean, and devise new measurements to be taken.
If you base your numbers on estimates, then you do not have a sound basis for proceeding. What the Kelvin Fallacy states is that if you have no basis for your facts, based on hard measured data, then you may have omitted a vital part of the estimates, so your numbers could be just plain wrong. So if you dont have any measurements, your numbers are suspect.
glc uses a series of formulae, all of which are absolutely correct, to estimate what a doubling of CO2 will do to global temperatures. He estimates this to be a rise of 1C. If something important has been omitted from his calculations, then they could be wrong. Until there is hard measured data on how much global temperatures rise as a result of putting more CO2 into the atmosphere from current levels, any estimated numbers that glc, or anyone else, comes up with, are suspect, because of the Kelvin Fallacy. The Kelvin Fallacy only refers to a lack of hard measured experimental data.
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Post by socold on Jul 17, 2009 17:34:07 GMT
McIntryres arguments are a total joke.
The IPCC report isn't supposed to be a physics textbook. His demands that it should be are just ridiculous. He is perfectly able to pick up a physics textbook, but he's made it clear before he doesn't want to discuss physics.
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Post by icefisher on Jul 17, 2009 17:35:39 GMT
Icefisher, have you started your Friday evening early? I sense your simplified physics argument is out there hanging by the big thread of faith in witch doctors no less. Yep I can buy 4 watts mucking around the top of the atmosphere along with that 1365 watts of solar energy making big red dogs and such. When you find one let me know.
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Post by icefisher on Jul 17, 2009 17:42:16 GMT
McIntryres arguments are a total joke. The IPCC report isn't supposed to be a physics textbook. His demands that it should be are just ridiculous. He is perfectly able to pick up a physics textbook, but he's made it clear before he doesn't want to discuss physics. As much as the IPCC wants to sell the idea why not humor him? Instead the IPCC spends inordinate time bowderlizing science reports. . . .seems so trivial when a simple and complete presentation is all they would have to ask from their scientists and just publish it. Instead everything needs to be jacked up like a con man selling the Brooklyn Bridge. No wonder the common man is not buying this rot!!
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Post by socold on Jul 17, 2009 17:45:57 GMT
Why would the IPCC process be trebled in complexity just to satisfy a handful of people that probably wouldn't be satisfied anyway (I highly suspect the info McIntyre asked for would go over his head anyway)
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Post by icefisher on Jul 17, 2009 17:54:30 GMT
Why would the IPCC process be trebled in complexity just to satisfy a handful of people that probably wouldn't be satisfied anyway (I highly suspect the info McIntyre asked for would go over his head anyway) If the IPCC cannot be bothered by a trebling of its efforts, I take that as a lack of commitment to the cause. The handful of people we are talking about here are the ones contesting the conclusions of the IPCC quite successfully. If they can't get it up for the challenge, well Socold you may as well pack your bags too. Adios!
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Post by socold on Jul 17, 2009 19:21:51 GMT
Why would the IPCC process be trebled in complexity just to satisfy a handful of people that probably wouldn't be satisfied anyway (I highly suspect the info McIntyre asked for would go over his head anyway) If the IPCC cannot be bothered by a trebling of its efforts, I take that as a lack of commitment to the cause. The handful of people we are talking about here are the ones contesting the conclusions of the IPCC quite successfully. If they can't get it up for the challenge, well Socold you may as well pack your bags too. Adios! Demanding the IPCC report comes attached with an atmospheric physics textbook is not a challenge, it's a silly excuse. It's silly because atmospheric physics textbooks are available, why not pick up one of those? The whole argument is just a means of creating a fuss. If the IPCC did attach a physics textbook to the report it would make no difference, the fussmakers would just be creating a fuss about something else irrelevant.
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Post by glc on Jul 17, 2009 20:04:01 GMT
glc uses a series of formulae, all of which are absolutely correct, to estimate what a doubling of CO2 will do to global temperatures. He estimates this to be a rise of 1C. If something important has been omitted from his calculations, then they could be wrong.
Jim
This is the equation that I 'used'. It is actually the intregrated form of the Schwarzschild equation.
I = I0(exp(-krz)) + B[1 - exp(-krz)]
Note there are 2 terms in the equation
Term 1 is an expression of the Beer-Lambert law of light absorption. Basically this calculates how much of the incident radiation passes directly through the absorbing medium, in this case, the atmosphere.
Term 2 is an expression for the emission of the absorbed radiation. In this term, B represents the planck function.
Together these terms tell us the total amount of energy transmitted - and, therefore, the amount absorbed in the atmosphere.
This equation, which you claim may be 'omitting something' uses Beer-Lambert and Planck - and nothing else. To show it is wrong you need to overturn long standing, well-established Physics. This part of the issue is not in doubt. You are confusing the debate about sensitivity with the forcing calculation. Doubling CO2 in the atmosphere will reduce the amount of outgoing IR by ~4 w/m2. If nothing else changes this will cause surface temperatures to increase by ~1 deg C.
The question is - will other factors respond and how. This is where the uncertainty lies. Some like Richard Lindzen and Roy Spencer believe the atmosphere will respond in such a way that the 1 deg increase is reduced. This is a negative feedback. Others believe, that because a warmer atmosphere will be able to hold more water vapour, then this will enhance the greenhouse effect still further and the 1 deg warming will be amplified. This is a positive feedback. If there is no feedback then around 1 deg of warming can be expected.
Finally a word about the above equation. This is an expression for a single wavelength at a given pressure, so to provide a calculation for the complete atmosphere, this equation needs to be calculated for every wavelength at multiple layers of the atmosphere and at different points around the world. In other words, there are millions of calculations. This is why programs like MODTRAN are used.
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Post by jimcripwell on Jul 17, 2009 20:40:15 GMT
glc. I agree wholeheartedly with everything you say. The numbers are all absolutely correct. However, what they mean is an entirely different matter. You claim that these numbers show that a doubling of CO2 will result in the earth's temperature rising 1 C. There is no experimental data to confirm this estimation. That is all I am saying. Just that there is no experimental data.
What is recognized in physics is that if there is no experimental data to confirm a set of estimations, then it is wrong to claim that anything has been proven. The only way you prove anything in physics is to make actual measurements. Now you may not believe this, but I do, and none of you theory is going to coinvince me that you have proved that doubling CO2 results in world temperatures that will rise 1C. It is just that simple.
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Post by northsphinx on Jul 17, 2009 22:28:33 GMT
Lets take a closer look of Schwarzschild equation. From: www.barrettbellamyclimate.com/USERIMAGES/Schwarzschild%20Equation%20for%20the%20transmission%20of%20radiation%20through%20an%20absorbing%20medium.docAnd here is the backward assumption again: "If a forcing of 3.7 W m-2 is caused by a doubling of CO2 concentration then = 231.3/390 = 0.593 and this gives Tsurface = 293.2 K, an increase of 1.3 K." This IF is not on solid ground. First: the outgoing LW radiation is not only from the surface. Much of it from clouds at higher altitudes= lower temperatures. Have been and will be. Second: I quote from the same article: "Although some parts of the CO2 spectrum show saturation in the Earth’s atmosphere and others that are near saturation there are two absorption bands which are very far from being saturated. So more CO2 will not help for parts of the spectrum. Third: Also from the same paper which i think say all about the 3,7W estimate: "Our main criticism of the GCMs is the amplification of their results by the use of positive feedbacks which are not fully understood and fraught with uncertainty, and the possible downplaying of the negative feedback from the evaporative water thermostat."
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Post by poitsplace on Jul 18, 2009 0:01:23 GMT
Yep, that's the problem...and something that's missing from most of the rough math. The temperature is the important thing. If the entire atmosphere were somehow at the same temperature as the ground the net affect of adding more CO2 would be zero. Every part of the atmosphere would be emitting just as strongly as it was absorbing. CO2's absorption is limited by the lowest temperature in the atmosphere (about 220K).
BUT...just as important as the lowest temperature is the reason its at that lowest temperature. There are numerous greenhouse gases in the atmosphere and numerous systems for getting the heat out to the radiating regions of the atmosphere. The PRIMARY greenhouse gas (water vapor) happens to emit at a MUCH higher temperature (around 270K). Because CO2 shares almost all of its spectrum with water vapor and because water vapor is free to just dump energy, unchecked, in the majority of its frequencies...most of the energy that's supposedly "trapped" by CO2 is simply re-emitted by water vapor.
The 220k region of the atmosphere is basically at 220k because it's denied energy. The region above is heated by UV absorbed directly by the sun. The regions below are warmed by the heated ground, water and the hydrological cycle.
Even if you make the horribly flawed assumption that CO2 is actually the limiting factor and that the 220k region is that temperature ENTIRELY because of CO2's interactions...the inclusion of the 220k emission by CO2 drops the absorption for a 280 to 600ppm increase in CO2 enough that it takes less than a 1C increase to offset the difference.
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Post by glc on Jul 18, 2009 1:37:07 GMT
"If a forcing of 3.7 W m-2 is caused by a doubling of CO2 concentration then Ċ = 231.3/390 = 0.593 and this gives Tsurface = 293.2
This IF is not on solid ground. First: the outgoing LW radiation is not only from the surface. Much of it from clouds at higher altitudes= lower temperatures. Have been and will be.
Irrelevant. Barrett's calculation is using a "back of the envelope" estimate of the the greenhouse effect or the transmission of energy, to be more precise. At an average temperature of ~15 deg C (288K) the earth emits ~390 w/m2. At TOA outgoing energy is ~235 w/m2. Hence net transmission is 0.603 (60%). Reduce 235 w/m2 by 3.7 w/m2 and net transmission is reduced to 0.593. It doesn't matter how it's reduced or why - it's the net effect that's important.
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Post by steve on Jul 18, 2009 10:08:00 GMT
I'm not attempting to give myself some wiggle room. I'm trying to explain that one of the problems is highly unlikely to succumb fatally to a new finding in physics (the calculation of CO2 forcing). You always insist on munging the whole problem together which makes it hard to get to grips with any of it. Any attempt to separate the problem into its components is ignored or rejected. I note that Steve McIntyre seems to take a similar line to you (I've attempted to debate this with him too, but he always goes quiet once the discussion starts). My way of thinking, and the way of many other physicists that I know as it happens, is to state what I know and try and understand what the situation would be if what I knew covered everything. You would say this opens one up to the Kelvin "fallacy". I would say that at least I know something, and when I observe things that don't align with my basis position, I have a starting point from which to work. Please steve, give us examples of your arguments with Steve McIntyre by pointing the specific thread on his forum where he "goes quiet" when your exquisite knowledge of physics overwhelms him. I'm not going to overstate my level of knowledge. The discussions I and other people had with McIntyre reached no further than those I've had with Jim. Steve McIntyre's sticking point is that he wants an "exposition" on how doubling CO2 leads to 2.5C of warming, and he wants it in less than 30 pages. The closest he got to engaging was in this thread: www.climateaudit.org/?p=1851He never accepts that climate sensitivity is a complex discussion (there is no fixed 2.5C figure) and he won't engage with any idea that such an exposition might involve more than one paper. Yet he then complains when individual papers don't contain enough detail. For example here, where he also gets confused about the difference between a radiation model and a GCM: "I'm well aware of these online calculators [MODTRAN], but I'd like to see an explanation of the underlying algorithms and assumptions. Are they based on radiative-convective models?" Just because he thinks that the standards of documentation of climate models is less complete than that of mining engineering doesn't make it so. While he refers to, and is childishly rude, about peer reviewed descriptions of models, if you look around you can find the technical documentation for models which is something quite separate.
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Post by icefisher on Jul 18, 2009 16:28:59 GMT
I'm not going to overstate my level of knowledge. Then what you should not question then is Steve's area of expertise. I know what Steve does and he does it very well as its what I do as well in a different field. Bottom line is complex stuff is very auditable. But when the client doesn't want you to audit it becomes even sometimes impossible. The government in such situations where the public interest is at stake will step in and seize all paper work. Thats the most difficult of audits as you have no help guiding you through the morass but at least it can be done in those circumstances through brute resorting and classifying of documents. Steve has made it clear that obstructionism to datasets is his biggest problem. Having a concise roadmap through the morass would be helpful as well. What I can say without exception is when you have neither the result always is because people have stuff to hide. Occasionally you run into one or the other, either sloppy work and not keeping records or incompetent help from somebody who does not understand the roadways. But when you run into a lot of both problems. . . .at the other end of the road you always find out there was an intentional reason. Thats because otherwise if people want people to understand they fall all over themselves to help you understand. Its human nature and its the number one clue to an investigator as to how that assistance is offered. I used to love Columbo and how he would always instantly zero in on the suspect and do his variety of hand to face moves everytime the criminal exposed himself. You claim all this is too complicated to roadmap. I understand that to mean its too weak to roadmap. Its like that observational study socold came up with on ice cores validating climate sensitivity numbers. Its all about a suggestion here and a clue there; but no clear physics, just little physical islands dotting a vast sea of unknowns. Its especially hilarious how the IPCC characterizes uncertainty in view of your point of view of complexity. I mean what is too complex? A 100 nodes? Do you know what 90% certainty is to the 100th power?
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