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Post by magellan on Oct 17, 2009 19:35:18 GMT
Come to the rescue? Enhance the warming? Reduce the warming? What warming? What warming needs to be reduced? The warming in your imagination?The warming that's likely to happen (and is probably already happening) from the increase in atmospheric CO2. The ~1 deg warming which will result by doubling the CO2 concentration. The warming that is accepted by most AGW-sceptical scientists including the following: Richard Lindzen, Patrick Michaels, Jack Barrett plus many, many others. Before you jump in with something about Richard Lindzen only thinks we'll get 0.3 or 0.6 or whatever. Richard Lindzen is arguing for negative feedbacks. He openly says that, all other things being equal, the warming will be ~1 deg (*see below), BUT he believes there will be a negative feedback which will reduce the warming (my option 2). He may turn out to be right, but how much of a gamble should we be prepared to take. * In this WUWT post wattsupwiththat.com/2009/03/30/lindzen-on-negative-climate-feedback/Richard Lindzen states "For example, if one simply doubles the amount of CO2 in the atmosphere, the temperature increase is about 1°C". "Simply", like in a static world. And of course you leave out another quote from Lindzen based on observational evidence presented in his most recent published paper: What we see, then, is that the very foundation of the issue of global warming is wrong. What is the very foundation of global warming? The issue of feedback mechanisms have been soundly investigated and embedded in climate models. See, the earth is like an egg precariously balancing on the head of a pin, waiting for the dreaded positive feedback to occur any day now. A totally unphysical process as evidenced in 99% of nature, but climate "science" is not bound to nature.  |
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Post by jimcripwell on Oct 17, 2009 19:42:53 GMT
glc writes "They are validated by earth's emission spectra."
Reference please. How can a model which deals with real situations be valid to estimate radiative forcing, which is a purely hypothetical situation? Please note, I agree that we can write equations which represent how radiation is transmitted through the atmosphere. What I dont understand is why these equations have anything to do with the estimation of radiative forcing.
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Post by nautonnier on Oct 17, 2009 20:22:44 GMT
icefisher:
I think even an IPCC Working Group agrees with you: Cloud Modeling is a major shortcoming in the models. At risk of referring you to something already familiar, perhaps one of these may be useful:Everyone agrees about the cloud issue. There is uncertainty but that is not a reason for the whole AGW theory to be ignored or dismissed. Cloud variability is a given but a number of sceptics seem to be relying on the fact that clouds may come to the rescue. They might - but then again they might not. We have not yet got sufficient evidence to say either way. Cloud variability is tied up with wv feedback which some think will be positive others think negative. There is nothing wrong with considering all possibilities. But, the fact is that, if all other factors remain the same, doubling the CO2 concentration is likely to warm the earth by about 1 deg. That shouldn't be a problem. But there's a strong possibility that all other factors will not remain the same. Other factors could act to 1. Enhance the warming 2. Reduce the warming There's your "uncertainty". It's your call. But remember this is not an experiment on another planet. I shall jump in at this point and ask _again_ for one of glc, SoCold or Steve to provide a calculation of how much energy is transferred to the tropopause by the hydrologic cycle and how much energy is reflected back to space due to the albedo of clouds formed by the hydrologic cycle and tell us the sum of the result in Watts per square metre at the tropopause. There will be some variance dependent on the surface (water or land) and temperature so a range of values with an average will be expected. No need for spurious accuracy - one decimal place will be enough. Then one can compare the capacity for energy transport by the hydrologic cycle to the 3.7WM -2 that supposedly comes from doubling the concentration of CO 2 in a slab atmosphere. This will allow a judgement as to whether the hydrologic cycle negative feedback has the capability to overwhelm the 'radiative forcing' from CO 2. The continual disregard of the hydrologic cycle as if it does not exist unless CO 2 is there to absorb some radiation is totally unscientific. After all there were storms and depressions and Hadley cells well before the industrial revolution. You will ignore this request as you have others I am sure. If this value cannot be provided then all the nice SB and de B equations are a total waste of time as they ignore the major energy transport to the tropopause. |
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Post by sigurdur on Oct 17, 2009 20:35:02 GMT
icefisher:
I think even an IPCC Working Group agrees with you: Cloud Modeling is a major shortcoming in the models. At risk of referring you to something already familiar, perhaps one of these may be useful:Everyone agrees about the cloud issue. There is uncertainty but that is not a reason for the whole AGW theory to be ignored or dismissed. Cloud variability is a given but a number of sceptics seem to be relying on the fact that clouds may come to the rescue. They might - but then again they might not. We have not yet got sufficient evidence to say either way. Cloud variability is tied up with wv feedback which some think will be positive others think negative. There is nothing wrong with considering all possibilities. But, the fact is that, if all other factors remain the same, doubling the CO2 concentration is likely to warm the earth by about 1 deg. That shouldn't be a problem. But there's a strong possibility that all other factors will not remain the same. Other factors could act to 1. Enhance the warming 2. Reduce the warming There's your "uncertainty". It's your call. But remember this is not an experiment on another planet. I shall jump in at this point and ask _again_ for one of glc, SoCold or Steve to provide a calculation of how much energy is transferred to the tropopause by the hydrologic cycle and how much energy is reflected back to space due to the albedo of clouds formed by the hydrologic cycle and tell us the sum of the result in Watts per square metre at the tropopause. There will be some variance dependent on the surface (water or land) and temperature so a range of values with an average will be expected. No need for spurious accuracy - one decimal place will be enough. Then one can compare the capacity for energy transport by the hydrologic cycle to the 3.7WM -2 that supposedly comes from doubling the concentration of CO 2 in a slab atmosphere. This will allow a judgement as to whether the hydrologic cycle negative feedback has the capability to overwhelm the 'radiative forcing' from CO 2. The continual disregard of the hydrologic cycle as if it does not exist unless CO 2 is there to absorb some radiation is totally unscientific. After all there were storms and depressions and Hadley cells well before the industrial revolution. You will ignore this request as you have others I am sure. If this value cannot be provided then all the nice SB and de B equations are a total waste of time as they ignore the major energy transport to the tropopause. nautonnier: Very valid questions and I do look forward to the people you requested to provide info to do so quit well. Bit of a challenge to AGW I would say. |
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Post by socold on Oct 17, 2009 20:43:20 GMT
icefisher:
I think even an IPCC Working Group agrees with you: Cloud Modeling is a major shortcoming in the models. At risk of referring you to something already familiar, perhaps one of these may be useful:Everyone agrees about the cloud issue. There is uncertainty but that is not a reason for the whole AGW theory to be ignored or dismissed. Cloud variability is a given but a number of sceptics seem to be relying on the fact that clouds may come to the rescue. They might - but then again they might not. We have not yet got sufficient evidence to say either way. Cloud variability is tied up with wv feedback which some think will be positive others think negative. There is nothing wrong with considering all possibilities. But, the fact is that, if all other factors remain the same, doubling the CO2 concentration is likely to warm the earth by about 1 deg. That shouldn't be a problem. But there's a strong possibility that all other factors will not remain the same. Other factors could act to 1. Enhance the warming 2. Reduce the warming There's your "uncertainty". It's your call. But remember this is not an experiment on another planet. I shall jump in at this point and ask _again_ for one of glc, SoCold or Steve to provide a calculation of how much energy is transferred to the tropopause by the hydrologic cycle and how much energy is reflected back to space due to the albedo of clouds formed by the hydrologic cycle and tell us the sum of the result in Watts per square metre at the tropopause. There will be some variance dependent on the surface (water or land) and temperature so a range of values with an average will be expected. No need for spurious accuracy - one decimal place will be enough. Then one can compare the capacity for energy transport by the hydrologic cycle to the 3.7WM -2 that supposedly comes from doubling the concentration of CO 2 in a slab atmosphere. I don't understand what you are trying to compare. The 3.7wm-2 is the reduction of energy loss into space if co2 is doubled but everything else remains the same in the atmosphere. Ie same amount of clouds, same amount of water vapor, convection, etc but double co2. It's the amount of additional energy absorbed by the additional co2 if nothing else in the atmosphere changesTherefore it's easy to calculate without having to know anything about how convection, clouds, etc might change in response. Ie the response is independent of the forcing. Until there's agreement on the forcing being about 3.7wm-2 I don't see any point discussing response. |
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Post by poitsplace on Oct 17, 2009 23:14:28 GMT
I don't understand what you are trying to compare. The 3.7wm-2 is the reduction of energy loss into space if co2 is doubled but everything else remains the same in the atmosphere. Ie same amount of clouds, same amount of water vapor, convection, etc but double co2. It's the amount of additional energy absorbed by the additional co2 if nothing else in the atmosphere changesTherefore it's easy to calculate without having to know anything about how convection, clouds, etc might change in response. Ie the response is independent of the forcing. Until there's agreement on the forcing being about 3.7wm-2 I don't see any point discussing response. The rest of the atmosphere DOES NOT remain the same. Water vapor, being kept at higher temperatures in lower parts of the atmosphere (and dealing with far more energy than CO2)...just skips the hell over the place it NORMALLY would have condensed and dumps its energy higher up. Oops, suddenly the CO2 has no way to absorb that much energy because it's already too darned hot. You CANNOT use parametrization to simplify the process (as models do) because they're impossible to separate. If CO2 won't let the heat pass as freely to that level through radiation, water vapor is forced to take its heat to that level through convection and latent heat. Also, adding more heat at ground level is only going to reinforce the water cycle so it moves that much more energy to undo any gradient change. At THESE temperatures water vapor significantly reduces any potential for CO2 to increase temperatures. Now in an ice age, CO2 might do more...but seriously, who the hell would worry about warming when its already too cold? |
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Post by nautonnier on Oct 17, 2009 23:51:08 GMT
I shall jump in at this point and ask _again_ for one of glc, SoCold or Steve to provide a calculation of how much energy is transferred to the tropopause by the hydrologic cycle and how much energy is reflected back to space due to the albedo of clouds formed by the hydrologic cycle and tell us the sum of the result in Watts per square metre at the tropopause. There will be some variance dependent on the surface (water or land) and temperature so a range of values with an average will be expected. No need for spurious accuracy - one decimal place will be enough. Then one can compare the capacity for energy transport by the hydrologic cycle to the 3.7WM -2 that supposedly comes from doubling the concentration of CO 2 in a slab atmosphere. I don't understand what you are trying to compare. The 3.7wm-2 is the reduction of energy loss into space if co2 is doubled but everything else remains the same in the atmosphere. Ie same amount of clouds, same amount of water vapor, convection, etc but double co2. It's the amount of additional energy absorbed by the additional co2 if nothing else in the atmosphere changesTherefore it's easy to calculate without having to know anything about how convection, clouds, etc might change in response. Ie the response is independent of the forcing. Until there's agreement on the forcing being about 3.7wm-2 I don't see any point discussing response. I knew you would find it difficult to understand SoCold Imagine a world without CO2 the hydrologic cycle would still operate, the major convective cells Hadley and Ferrel and the Polar vortices would still be there. Winds and convective weather would still exist as would all the oceanic and atmospheric effects that they would cause. So its simple to calculate I would think and like radiative forcing its a nice hypothetical - how much energy would be transported to the tropopause by the hydrologic cycle rather than by radiation and how much inbound energy would be reflected away by albedo changes due to clouds in the absence of any GHG. In units of Watts per square metre at the tropopause to the nearest one place of decimals so we can compare the hydrologic cycle heat transport with radiation outbound and with the hypothetical radiative forcing from CO 2. If you cannot provide a figure I will understand - but then you may not want to as it may be an order of magnitude or two more than the 3.7WM -2 claimed for CO 2. Then when we have an idea of the order of magnitude we can identify what the effect if any of the CO 2 absorption might be. Remember (for glc) we are talking of transport to the tropopause NOT the TOA - that way we are using matching measurement points. If there is no quantification of the hydrologic cycle both negative and positive then the entire AGW logic is fatally flawed as there is no quantification of energy that completely bypasses the CO 2 absorption nor is there any quantification of the feedbacks both negative and positive. |
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Post by socold on Oct 18, 2009 0:02:48 GMT
I don't understand what you are trying to compare. The 3.7wm-2 is the reduction of energy loss into space if co2 is doubled but everything else remains the same in the atmosphere. Ie same amount of clouds, same amount of water vapor, convection, etc but double co2. It's the amount of additional energy absorbed by the additional co2 if nothing else in the atmosphere changesTherefore it's easy to calculate without having to know anything about how convection, clouds, etc might change in response. Ie the response is independent of the forcing. Until there's agreement on the forcing being about 3.7wm-2 I don't see any point discussing response. The rest of the atmosphere DOES NOT remain the same. Exactly. It cannot because 3.7wm-2 is a significant imbalance which cannot be maintained. Therefore the climate system must change in response to a doubling of co2. It cannot remain in the same configuration. Hence the old "doubling co2 has no effect on the climate canard" is false. For example you say: So doubling co2 causes precipitation patterns to change significantly? Who would have thought it from skeptic claims that doubling co2 doesn't cause any effect whatsoever? I think we have yet another skeptic contradiction here. A "doubling co2 has no effect on climate" vs a "doubling co2 increases cloud cover" kind of contradiction. Or things simply warm up. Warm up = more radiated energy = more getting through again. And we are back to equilibrium. |
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Post by enough on Oct 18, 2009 0:18:09 GMT
Steve wrote: Here's the reference for the 3.7W/m^2 number.
New estimates of radiative forcing due to well mixed greenhouse gases
Gunnar Myhre et al GRL 1998enough replied I have read this paper. It is the usual...........Some time ago I emailed Jack Barrett about a number of climate issues including the Myhre et al 'equation'. This is part of his reply This simple equation is derived by Excel curve-fitting to data produced from a model for CO2 concentrations between 300-600 ppmv. It is not derived from basis physics, although one might expect the relationship to be logarithmic from the Beer-Lambert Law of light absorption. I don't regard it to be well established, but the IPCC use it as the basis of their predictions. It gives the 'forcing' without any feedbacks and it is those that give rise to the many and varied forecasts of future climate that have been sold to the policy makers. I think the equation is not far from the mark, however, and the MODTRAN program that I use gives similar results, again it is what effects the feedbacks have that give rise to the various predictions. Myhre & Co. altered their initial estimate of the coefficient in their equation, down-grading it by 15% in a later paper (attached).
Regards
JackMost of the leading climate scientists have come up with their own independent estimates for 2xCO2 forcing. There is nothing particularly special about the Myhre equation. It's just a simple expression to estimate CO2 forcing. But, as Jack says, it's "not far from the mark". So he used excel to fit an equation to a model output...and this the the definitive answer. I am not even going to comment on this one...... From an earlier coment about models building on models. I guess that is similar to how tree ring generated hockey sticks self propagate. |
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Post by socold on Oct 18, 2009 0:31:20 GMT
If you cannot provide a figure I will understand - but then you may not want to as it may be an order of magnitude or two more than the 3.7WM -2 claimed for CO 2. Even if it was, unless convection changes it isn't going to cancel out any of that 3.7wm-2 imbalance. As I said in my last post the 3.7wm-2 figure for doubling co2 is based on everything else in the atmosphere remaining the same. That goes for convection too. The planet will respond to counter the 3.7wm-2 imbalance. One way it can do that is to warm up. This is what the physics calculations show. If you want to know specific results of these calculations such as how much energy is transported by convection to specific heights you'll have to track it down yourself, I don't know and assume you'd need to analyze that kind of model output to find out. Not something I have done and not something I plan on learning how to do. As for convection in general as part of a solution to the imbalance - I have no idea how that would work. Do you need convection to increase or decrease? Which way round cools the planet? Increasing convection cools the surface and warms the atmosphere. But does that result in more outgoing energy? I don't know. In any case convection needs to change in order to solve the imbalance. Ie the hypothesis would be that doubling co2 changes convection. That alone signifies that co2 isn't some irrelevant trace gas if we can alter convection by doubling it. Of course there's quantification. The models. |
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Post by sigurdur on Oct 18, 2009 0:32:17 GMT
Steve wrote: Here's the reference for the 3.7W/m^2 number.
New estimates of radiative forcing due to well mixed greenhouse gases
Gunnar Myhre et al GRL 1998enough replied I have read this paper. It is the usual...........Some time ago I emailed Jack Barrett about a number of climate issues including the Myhre et al 'equation'. This is part of his reply This simple equation is derived by Excel curve-fitting to data produced from a model for CO2 concentrations between 300-600 ppmv. It is not derived from basis physics, although one might expect the relationship to be logarithmic from the Beer-Lambert Law of light absorption. I don't regard it to be well established, but the IPCC use it as the basis of their predictions. It gives the 'forcing' without any feedbacks and it is those that give rise to the many and varied forecasts of future climate that have been sold to the policy makers. I think the equation is not far from the mark, however, and the MODTRAN program that I use gives similar results, again it is what effects the feedbacks have that give rise to the various predictions. Myhre & Co. altered their initial estimate of the coefficient in their equation, down-grading it by 15% in a later paper (attached).
Regards
JackMost of the leading climate scientists have come up with their own independent estimates for 2xCO2 forcing. There is nothing particularly special about the Myhre equation. It's just a simple expression to estimate CO2 forcing. But, as Jack says, it's "not far from the mark". So he used excel to fit an equation to a model output...and this the the definitive answer. I am not even going to comment on this one...... From an earlier coment about models building on models. I guess that is similar to how tree ring generated hockey sticks self propagate. The 3.7W-m2 is really a quit useless figure. It was derived using a slab model which everyone knows. The whole point is the sensativity of the climate verses the models of the climate. The whole debate about AGW losses all scientific credibility because the basis of said debate is that slab model. The climate, as we all know is not a slab. The sensativity is totally unknown. Lots of conjecture, but not one ounce of certainty as it is all guess work. With that being said again, even if the sensativity is a 1.0C increase in temps.....is this out of the ordinary? NO IT IS NOT. I just can't understand why anyone gets excited over a projection that happened less than 8,000 years ago. I recognize that the temps from 8,000 years ago come from proxie data, but I have not seen a large debate over those temps so the data musttttt be 1/2 way scientifically decent. So.......folks tell me.......why the excitement? Is it induced? Does normal climate flucuation scare you that badly? I just don't understand the hysteria. Adapting to warmer temps would be a whole lot easier than adapting to colder temps. |
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Post by socold on Oct 18, 2009 0:34:24 GMT
So he used excel to fit an equation to a model output...and this the the definitive answer. No the definitive answer is the model output part. Ie there is no simple sentence answer. The forcing is derived from a load of calculations based on radiative physics. Something which cannot be reproduced here due to it's quantity. |
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Post by glc on Oct 18, 2009 0:39:40 GMT
So he used excel to fit an equation to a model output...and this the the definitive answer.
The "model output" is not "model output" as you might understand it. In this case computer programs are used because of the number of calculations involved. In order to accurately calculate the transmission of radiation through the atmosphere it is necessary to perform thousands of calculations. It can ony be done on computer. Note that many of the programs pre-date the recent AGW movement.
Myhre took the output from these programs and used it to fit a simple log function. It's a perfectly reasonable thing to do. Unfortunately anything that results from a computer program appears to be treated with suspicion.
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Post by icefisher on Oct 18, 2009 0:41:09 GMT
Even if it was, unless convection changes it isn't going to cancel out any of that 3.7wm-2 imbalance. As I said in my last post the 3.7wm-2 figure for doubling co2 is based on everything else in the atmosphere remaining the same. That goes for convection too. If?  ?? LOL! Convection starts changing every morning when the sun comes up and changes again when the sun goes down, not to talk about shifting and changing all day long. How ridiculous!!! If convection changes. . . .ROTFLMAO!!! The models can't quantify anything unless somebody parameterizes them and its impossible to realistically parameterize the models unless you have a cloud model. . . .so I guess Jim Hansen sticks his finger in the air and picks a number. |
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Post by socold on Oct 18, 2009 0:50:33 GMT
The 3.7W-m2 is really a quit useless figure. It shows doubling co2 has a significant effect on climate. A 3.7wm-2 imbalance requires a substantial climate change to solve. GCMs do not have slab atmospheres and are not fed the 3.7wm-2 figure. GCMs calculate the climate response to doubling co2 by doubling co2 and calculating the subsequent changes in convection, temperature, etc. The radiative forcing is useful for roughly comparing the magnitude of different forcing. Radiative forcing is easier to calculate, you don't need GCMs to do it. Multiple lines of evidence all lean towards a similar range of climate sensitivity. www.iac.ethz.ch/people/knuttir/papers/knutti08natgeo.pdfThe lines of evidence mentioned above suggest it is higher than 1C, possibly much higher. |
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