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Post by socold on Oct 11, 2009 4:15:05 GMT
socold writes "Science shows us that the forcing from a doubling of co2 is about 3.7wm-2." Wrong. The output of non-validated computer programs gives an estimate of 3.7 wm-2. You are wrong, they have been validated. This is an undisputed number in science, it's well grounded in physics and the uncertainty is very low. I don't really care if you want to pretend it's up for debate, I will just make it clear I disagree with you. |
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Post by socold on Oct 11, 2009 4:21:15 GMT
socold writes "Science shows us that the forcing from a doubling of co2 is about 3.7wm-2." Wrong. The output of non-validated computer programs gives an estimate of 3.7 wm-2. Science tells us absolutely nothing at all. This number can NEVER be measured, so there is no physics, and therefore no science, behind the number you quoted. Socold may be correct in what he posted. The part he forgot to include is that forcing only works in a slab atmosphere, of which we do not have. For that amount of forcing, everything else MUST remain totally stationary. No more clouds, no fewer clouds, no more wind, no less wind etc. That.....well.......isn't happening is it? The forcing from a doubling of co2 describes how much more energy the Earth will be gaining. How the climate system rearranges itself when it starts gaining such an extra amount of energy and how much temperature change results is the climate response. Climate forcing is not the same as temperature change. But if you insist the climate responds to a forcing to minimize temperature change then you require a big forcing to explain temperature changes. Here's something else interesting www.skepticalscience.com/How-do-we-know-CO2-is-causing-warming.html |
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Post by socold on Oct 11, 2009 4:31:36 GMT
I've already said before that physics in models is not perfect (ie reality of physics). But it is the only physics And the FACT that the models are just flat out WRONG is what we're talking about. Since the change to the tropospheric gradient is a fundamental component and responsible for a large amount of the temperature increase proposed by the models... It isn't a fact no matter how much you capitalize it. It could be the measurements that are wrong given the uncertainty in them. Time will tell. |
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Post by poitsplace on Oct 11, 2009 6:34:01 GMT
socold writes "Science shows us that the forcing from a doubling of co2 is about 3.7wm-2." Wrong. The output of non-validated computer programs gives an estimate of 3.7 wm-2. You are wrong, they have been validated. This is an undisputed number in science, it's well grounded in physics and the uncertainty is very low. I don't really care if you want to pretend it's up for debate, I will just make it clear I disagree with you. That number is for the raw math for absorption by CO2, not the amount we'll get in a dynamic atmosphere. This is not unlike the acceleration of gravity...a well established concept in physics but which fails utterly to work on bodies falling long distances within the earth's atmosphere. Of course eventually they learned to calculate to find wind resistance but then OOPS, it failed utterly to predict behavior of falling objects moving beyond a certain speed because they didn't know about the shockwaves forming around things as they approached the speed of sound. Today, even though it's a fairly straight forward concept and even though we've been able to tweak the models with literally MILLIONS of observations of objects at greater than the speed of sound...nature still throws us a curve ball and produces behaviors not predicted by the models. So while the number on absorption by CO2 is pretty firmly established its effects are not. You can actually see that the effects aren't established because there's almost an order of magnitude of difference in the output of the models even between the models of alarmists. Of course, we're pretty much certain that the high end models are in fact wrong because they require such incredibly high rates of warming that natural variation couldn't possibly cover that much warming for between 2years for the recent, delusional 9C by 2100 projections, or 10 years for the high end IPCC models. Yep, the longer we go without significant warming (or as long as we have cooling) the lower the maximum sensitivity falls. The only "validation" of computer models has been to make sure the code accurately does what the programmer intended...not that they match reality. So far reality has had different plans. |
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Post by nautonnier on Oct 11, 2009 10:14:35 GMT
socold writes "Science shows us that the forcing from a doubling of co2 is about 3.7wm-2." Wrong. The output of non-validated computer programs gives an estimate of 3.7 wm-2. You are wrong, they have been validated. This is an undisputed number in science, it's well grounded in physics and the uncertainty is very low. I don't really care if you want to pretend it's up for debate, I will just make it clear I disagree with you. IPCC Definition of Forcing: "The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values."Definition of Validation: " In computer modeling and simulation, the process of determining the degree to which a model or simulation is an accurate representation of the real world from the perspective of the intended uses of the model or simulation."www.thefreedictionary.com/validationI don't know what definition of validation you are using SoCold - but there is NO way a hypothetical construct such as Radiative Forcing can be 'validated'. |
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Post by jimcripwell on Oct 11, 2009 10:45:36 GMT
socold writes "You are wrong, they have been validated."
Fair enough. Please supply some references. Let me be quite clear what I am talking about. This is merely trying to amplify what nautonnier and poitsplace have written. I am quite prepared to believe that the equations in the various computer models produce the numbers you claim. However, I challenge the idea that the equations properly model how the real atmosphere works.
Where is the reference that proves that the way the atmosphere is modelled is close enough to reality that the estimate of 3.7 wm-2 is valid?
While we are about it, do you agree that the estimated value of 3.7 wm-2 has not been experimentally measured? Yes or no.
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Post by socold on Oct 11, 2009 12:06:42 GMT
You are wrong, they have been validated. This is an undisputed number in science, it's well grounded in physics and the uncertainty is very low. I don't really care if you want to pretend it's up for debate, I will just make it clear I disagree with you. That number is for the raw math for absorption by CO2, not the amount we'll get in a dynamic atmosphere. This is not unlike the acceleration of gravity...a well established concept in physics but which fails utterly to work on bodies falling long distances within the earth's atmosphere. It's not unlike a 1% increase in solar output providing 2.4wm-2 forcing. That's also raw math. It's robust math though, with a very small and tidy error range. We can see by comparing potential 21st century forcings alone that the forcing from doubling of co2 is the most significant one. Nothing comes close to the 3.7wm-2 from doubling co2. How the Earth's temperature changes in response to forcing is he climate's sensitivity. Climate sensitivity is in units of degrees C per wm-2 forcing. Therefore if a doubling of co2, with forcing 3.7wm-2, only causes 0.01C warming, climate sensitivity would be 0.003C/wm-2. But this has consequences. For example to explain a 5C warming event in a climate with 0.003C/wm-2 sensitivity a 1667wm-2 forcing is needed. That's implausibly large. It would be akin to a seven-fold increase in solar output. Therefore basic rough considerations of the science alone are strongly against such a low amount of warming from co2. I agree but the uncertainty range is firmly in the area of high climate sensitivity. In fact it's between high and very high. I am not aware of 9C by 2100, but be aware that with high climate sensitivity the temperature response to an accumulating forcing will be exponential. That covers the behavior of most of the high end ranges. |
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Post by socold on Oct 11, 2009 12:11:18 GMT
You are wrong, they have been validated. This is an undisputed number in science, it's well grounded in physics and the uncertainty is very low. I don't really care if you want to pretend it's up for debate, I will just make it clear I disagree with you. IPCC Definition of Forcing: "The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values."Definition of Validation: " In computer modeling and simulation, the process of determining the degree to which a model or simulation is an accurate representation of the real world from the perspective of the intended uses of the model or simulation."www.thefreedictionary.com/validationI don't know what definition of validation you are using SoCold - but there is NO way a hypothetical construct such as Radiative Forcing can be 'validated'. Here's one study that has validated the expected forcing: www.nature.com/nature/journal/v410/n6826/abs/410355a0.htmland another one: ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm |
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Post by jimcripwell on Oct 11, 2009 14:07:34 GMT
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Post by jimcripwell on Oct 11, 2009 16:05:14 GMT
socold. Again thanks for the references, which I find to be totally unconvincing. First let us be clear what the issue is. What we need is a quantitative measure of what effect marginally doubling CO2 from current levels, has. My original idea was a change of 0.01 C. Let me rephrase this to a change in radiative forcing of 0.037 wm-2. Again, let me restate that it is impossible to design an experiment to actually measure such a quantitative number. You have not commented on this assertion.
Neither of your references address the main issue. This is, why are radiative transfer models suitable to estimate changes in radiative forcing? I object to Myhre et al 1998 stating that they have used 3 radiative transfer models, without showing that such models have been validated to estimate radiative forcing. Until I see this sort of reference, I will be absolutely unconvinced that anyone has established a quantitative measure for the doubling of CO2 from current levels, using radiative transfer models.
Your second reference does not seem to address this issue. It seems to show that greenhouse gases keep the atmosphere warm; I am surprised that it is felt necessary to establish this. Of course water vapor, and to a much less extent CO2, keep the atmosphere warm. This paper does not address what is a quantitative measure for marginally increasing CO2 from current levels. If I am wrong, I am open to education.
I have seen the first reference before. What struck me about it was that it ought to have been possible to calculate the change in radiative forcing for a doubling of CO2, but it did not. I could not understand why. It has all the ingredients for doing the calculations, but they were not done. This convinced me that this paper was merely propaganda. Had the authors actually done the calculations, I suspect the number obtained would have been significantly less than 3.7 wm-2. However, I have no way of proving this.
So I remain totally unconvinced that anyone has established a quantitative measure for how much effect a doubling of CO2 has from current levels.
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Post by socold on Oct 11, 2009 16:31:00 GMT
socold. Again thanks for the references, which I find to be totally unconvincing. First let us be clear what the issue is. What we need is a quantitative measure of what effect marginally doubling CO2 from current levels, has. My original idea was a change of 0.01 C. Let me rephrase this to a change in radiative forcing of 0.037 wm-2. Again, let me restate that it is impossible to design an experiment to actually measure such a quantitative number. You have not commented on this assertion. The models are that quantitative measure. They find that by doubling co2 levels in the atmosphere the outgoing radiation is reduced by 3.7wm-2. Ie 3.7wm-2 additional is absorbed. Because radiative transfer models are accurate enough to do that. Radiative forcing remember is simply the radiative imbalance caused by something before the climate responds to that imbalance. Therefore given that the absorption properties of co2 are well known from lab and experimental studies, ie the basis of the radiative transfer models, it's possible to put it all together to calculate the additional absorption if there was twice as much co2 in the atmosphere. In parallel to this it's also possible to know the radiative forcing from solar output increases too without actually doing that. The radiative forcing from a 1% increase in solar output is about 2.5wm-2, given that the Earth absorbs about 240wm-2 solar energy. Of course noone has done an experiment in that case either, but the result is clearly true nevertheless. The co2 case takes some more calculation but it is also possible to figure it out without having to actually double co2 in the atmosphere. |
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Post by jimcripwell on Oct 11, 2009 19:02:08 GMT
socold writes "Because radiative transfer models are accurate enough to do that. Radiative forcing remember is simply the radiative imbalance caused by something before the climate responds to that imbalance."
Here is where we part company. I am not querying the ACCURACY of the radiative transfer models. I am arguing about their SUITABILITY. As nautonnier has pointed out this time, and I have pointed out many times in the past, radiative forcing is a hypothetical concept. viz
"The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values."
If the " surface and tropospheric temperatures and state held fixed at the unperturbed values", then how can this possibly be a real situation? Since radiative transfer models deal with real situations, they cannot possibly deal with hypothetical ones. Or is this an error? I have still not seen any reference which proves that radiative transfer models are valid to estimate radiative forcing values. Your rather naive explanation is no substitute for a proper explanation.
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Post by enough on Oct 11, 2009 19:22:06 GMT
socold. e not commented on this assertion. Because radiative transfer models are accurate enough to do that. Radiative forcing remember is simply the radiative imbalance caused by something before the climate responds to that imbalance. Therefore given that the absorption properties of co2 are well known from lab and experimental studies, ie the basis of the radiative transfer models, it's possible to put it all together to calculate the additional absorption if there was twice as much co2 in the atmosphere. This is not true, the so called 4 watt forcing came from so very early papers that used global circulation models. Books you should go buy. The used ones are inexpensive. Atmospheric Radiation by R.M. Goody ISBN 0-19-505134-3 This book has the IR graph that everyone likes to quote. Goody has some very derogatorily comments about computer models that are impossible to review. Buy the book I will point you to the section. Principles of Atmospheric Physics and Chemistry by RM Goody ISBN 0-19-509362-3 In this book he provides a simple green house model that uses the lapse rate coupled to the a Chapman radiation layer using a Gray atmosphere. This simple model gives a 1 deg C forcing. For various reasons his impression in his latest papers are that a co2 doubling provides only a .5c forcing. Reasons among The IR path to space has many parallel paths, dominate being 10 micron window Low level moisture Cloud tops CO2 at the statopause On this elusive 4 watt co2 forcing, if you have a modern reference please provide??? I see this refereed to all over the place. But never a reference. Even in so called peer reviewed papers. The NASA GISS models have been soundly falsified by Argos data. The nonsense about heat getting lost in the deep ocean is BS. The sun penetrates the top 200 feet. You can see the annual cycle in the data. (Sun distance). The deep lags the surface by a 1000 years. Back to the original question. Does anyone have any thing to substantiate Soloms claim of a 1000 years other that trust the models? |
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Post by icefisher on Oct 11, 2009 20:24:02 GMT
We can see by comparing potential 21st century forcings alone that the forcing from doubling of co2 is the most significant one. Nothing comes close to the 3.7wm-2 from doubling co2. . . . .I agree but the uncertainty range is firmly in the area of high climate sensitivity. In fact it's between high and very high. I would say thats a pretty ignorant view of the matter. Now a 3.7watt increase in sunlight hitting the surface would be subject to one level of sensitivity, while 3.7 watts at the top of the atmosphere would be subject to another. Undoubtedly climate sensitivity varies depending upon where the forcing is applied. Just basic physics. The CO2 warming model might look like a double boiler with a warming element in the top pot and a spouted teapot for the bottom. Compared to heating from the bottom it would likely require several times the wattage in the upper pot to get the same result in the teapot on the bottom. . . .as evidenced by the hotspot theory. When a warmista says "firmly within" or "90% confidence" they really mean "the slight chance of an icecube in Hades". |
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Post by socold on Oct 11, 2009 20:31:23 GMT
socold writes "Because radiative transfer models are accurate enough to do that. Radiative forcing remember is simply the radiative imbalance caused by something before the climate responds to that imbalance." Here is where we part company. I am not querying the ACCURACY of the radiative transfer models. I am arguing about their SUITABILITY. As nautonnier has pointed out this time, and I have pointed out many times in the past, radiative forcing is a hypothetical concept. viz "The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values." If the " surface and tropospheric temperatures and state held fixed at the unperturbed values", then how can this possibly be a real situation? Because it's a measure of the energy imbalance caused. If you let the surface and troposphere respond there will be no inbalance. You'll get warming which will tear the imbalance back down to zero. As Earth can only gain or lose energy through radiation, that is the measure used to compare different causes. Ie quantify how much additional energy in vs out is caused by a 1% solar increase and from a doubling of co2 and then can compare the numbers. |
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