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Post by ron on Mar 1, 2009 20:03:13 GMT
All the discussion about IR absorption of co2 and convection as if they can somehow make co2 insignificant seem to miss the fact that this stuff is already in the models. ...and the clouds?
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Post by nautonnier on Mar 1, 2009 23:22:31 GMT
The models show significant warming from co2. Not significant warming over every 8 year period. Neither do they imply Mars should be a hot house. The models are the best physical calculations of long term climate we have. All the discussion about IR absorption of co2 and convection as if they can somehow make co2 insignificant seem to miss the fact that this stuff is already in the models. I suggest you re-read AR4 that shows the model output you will see that the models DO show significant warming. There is NO caveat saying this is what CO 2 will do as long as everything else stays constant. The ensemble of models shows a continual linear warming. Three of four of the 17 models show brief 1 - 2 year inflections (at different times) but otherwise it is a linear climb in line with CO 2 concentrations. You are wrong in what you state.
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Post by socold on Mar 2, 2009 7:30:41 GMT
Not significant warming over every 8 year period.
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Post by socold on Mar 2, 2009 7:37:49 GMT
What the heck, man...the earth isn't as good a model of its self as our computer models? Line fitting is an inferior "model" of the earth. It isn't really even a model. I could fit your lines showing an exponential increase. You don't have enough data to establish any sort of pattern and besides the forcings in the late 20th century are different than in the early 20th century so there's no reason for the same pattern throughout.
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Post by steve on Mar 2, 2009 7:40:40 GMT
The models show significant warming from co2. Not significant warming over every 8 year period. Neither do they imply Mars should be a hot house. The models are the best physical calculations of long term climate we have. All the discussion about IR absorption of co2 and convection as if they can somehow make co2 insignificant seem to miss the fact that this stuff is already in the models. I suggest you re-read AR4 that shows the model output you will see that the models DO show significant warming. There is NO caveat saying this is what CO 2 will do as long as everything else stays constant. The ensemble of models shows a continual linear warming. Three of four of the 17 models show brief 1 - 2 year inflections (at different times) but otherwise it is a linear climb in line with CO 2 concentrations. You are wrong in what you state. As socold has pointed out, you are wrong, Nautonnier. We've had this discussion before, so I don't understand why you keep saying this. I'm also curious about your 8.5% number for CO2. I've got two questions. 1. Why do you think being able to quote an apparently small number makes the case against CO2? Remember, the theory goes that doubling CO2 reduces outgoing longwave radiation by about 2%. 2. Where did you get the number from? One place I've seen this number is in a site called nov55 which appears to be owned by someone who should only be allowed to write in crayon.
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Post by poitsplace on Mar 2, 2009 9:10:08 GMT
What the heck, man...the earth isn't as good a model of its self as our computer models? Line fitting is an inferior "model" of the earth. It isn't really even a model. I could fit your lines showing an exponential increase. You don't have enough data to establish any sort of pattern and besides the forcings in the late 20th century are different than in the early 20th century so there's no reason for the same pattern throughout. Actually drawing a line between peaks or troughs should give a high estimate since the affects of CO2 are logarithmic. Your chart above is exponential and should therefore be suspect at a glance. But, hey...you keep on believing whatever you want based on whatever false assumptions and computer models you want to use.
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Post by steve on Mar 2, 2009 11:34:47 GMT
Stating the "effects of CO2 are logarithmic" is just a tired mantra that you use in the hope that it causes someone to believe that all the effects of CO2 will fit a logarithmic curve.
The amount of radiative forcing caused by CO2 can be modelled as a logarithm.
The rate of CO2 increase is, over the past few decades, slightly more than linear. In the scenario shown by socold there will be a prescribed level of CO2. A2 is at the pessimistic end with CO2 levels rising slightly faster than linear upto 2100 due to increasing levels of emissions.
The response of the oceans is expected to be quite slow because of its large thermal mass.
There are other feedbacks such as loss of sea ice that would affect the rate of warming.
Models aim to calculate all the factors in a way that is (quite strongly) arguably better than line-fitting which is prone to selection effects and cherry-picking.
When all the factors are taken into account the "logarithmic" nature of some aspect of CO2 is just one small element among many others resulting in an apparent linear or slightly super-linear increase in temps.
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Post by poitsplace on Mar 2, 2009 17:30:47 GMT
Stating the "effects of CO2 are logarithmic" is just a tired mantra that you use in the hope that it causes someone to believe that all the effects of CO2 will fit a logarithmic curve. The amount of radiative forcing caused by CO2 can be modelled as a logarithm. The rate of CO2 increase is, over the past few decades, slightly more than linear. In the scenario shown by socold there will be a prescribed level of CO2. A2 is at the pessimistic end with CO2 levels rising slightly faster than linear upto 2100 due to increasing levels of emissions.[/quote] One teeny, tiny little hiccup in your reasoning. For the logarithmic nature of CO2 increases to show a linear increase the "feedbacks" would need to be pretty much exponential...causing massive, unstoppable feedback that pushes climate all the way to whatever extremes it can hit...permanently. Except of course the MODELS assume it's entirely caused by CO2 and that little is natural. Never mind that much of the warming was because we were (for NO KNOWN REASON so far as alarmists are concerned) coming out of the little ice age. No, forget all we've observed, we'll just blindly plot along with the stupid assumption that a gas that would at best promote a logarithmic increase in temperatures will produce a linear to exponential increase in temperature. AGW projections are without question PURE FANTASY as the feedbacks they propose are so great that they would be able to drive themselves the moment temperature rose. Worse still is that this (outright stupid) assumption that feedbacks are greater than 1 to 1 would mean that whatever is forcing the ice ages would require unimaginable energy imbalances just to overcome the insane warming...far more than any cycle or solar variation could EVER produce. Remember, the "feedback" is not based on CO2, it's based on temperature. Imagine if your stove top had a similar mechanism. It would direct more energy to the unit if you turned the knob OR if it warmed. If you turned the control enough to warm it 1C it would warm 2C...but then because it had warmed 2C it would warm more...but because it had warmed more it would warm that much more. Worse still, if your home warmed by 1C the burner would likewise warm by 2C...and again, warm by 2C because it was then 2C warmer. The only way to keep the burner from going crazy would be to cool it back off by pouring water or ice on it before it got too hot. You'd actually have to keep it below it's threshold the whole time so it could never start feedback. The models showing a long term, super-linear increase driven by a logarithmic forcing are just wrong. Some other natural forcings must be responsible for the bulk of the increases...and I get the feeling that we're not only about to find out that out for certain, but that we're going to be reminded once again that a cold, not heat, is the REAL killer of men AND civilizations.
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Post by socold on Mar 2, 2009 19:47:20 GMT
One teeny, tiny little hiccup in your reasoning. For the logarithmic nature of CO2 increases to show a linear increase the "feedbacks" would need to be pretty much exponential... Or, the co2 increase needs to be exponential... No the models do not assume that. The climate sensitivity from a doubling of co2 is an output of the climate models, not an input/assumption. We were probably already out of the little ice by the turn of the 20th century. Nope, the proposed feedbacks can't drive themselves. In the case of climate feedbacks it's about 0.6C additional warming for each 1C increase. Not enough to keep it going infinitely, it levels out at about 3C.
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Post by poitsplace on Mar 2, 2009 22:11:31 GMT
We were probably already out of the little ice by the turn of the 20th century. 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. It took decades just to tweak and tweak the things to hindcast with anything remotely approaching accuracy...and then it STILL doesn't predict right. We're outside the error bars, the assumptions were incorrect. That's the problem, the models are based on assumptions of forcings that are not understood. LOL, I never realized ice could tell the difference between the heat caused when ground is exposed and the heat caused when CO2 warms the planet. Would you care to try again? In the case of climate feedbacks it's about 0.6C additional warming for each 1C increase. Not enough to keep it going infinitely, it levels out at about 3C. [/quote] Again, the models are neither fact nor science. They give no clue as to why the climate fluctuated in the past and as such are unable to tell if this warming is truly from CO2 or not. I mean to even get significant warming from CO2 you actually have to pay attention to only one aspect of the physics of its energy interactions. Of course, THIS is the time to test those assumptions of the climate models. We've got several contenders for climate forcings that MUST have been driving the climate toward a warmer state to some extent...and they've just gone negative. If the previous warming trend continues the hypothesis of significant global warming obviously needs SERIOUS revision. If the temperatures fall at a higher rate than they did in the previous cooling period...substantial global warming will have been disproven. ...or at the very least we'll have just helped to keep ourselves out of another little ice age
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Post by donmartin on Mar 3, 2009 7:05:43 GMT
Could some one direct me to an experiment by any one which showed beyond reasonable doubt that carbon dioxide, or gases such as carbon dioxide absorbs or can absorb "energy" with the result that the atmosphere containing the gases, or the gas itself, becomes warmer?
Thank you
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Post by steve on Mar 3, 2009 10:18:24 GMT
poitspace,
The models *do* model the climate extremes of the past. That is one of the tests that is done on models. As we don't know the exact conditions of all the climate drivers of the past (solar strength, amount of ice, orography, atmospheric composition, ocean currents, albedo, plant distribution) there is of course uncertainty. There is certainly a big gap in reconstructions of the ice age cycles that needs to be filled either by *something unknown* or, perhaps, by a water vapour related feedback.
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!
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Post by steve on Mar 3, 2009 10:53:28 GMT
Could some one direct me to an experiment by any one which showed beyond reasonable doubt that carbon dioxide, or gases such as carbon dioxide absorbs or can absorb "energy" with the result that the atmosphere containing the gases, or the gas itself, becomes warmer? Thank you You have to go back a long way for the basic science. These days, properties of such gases are important in many different engineering areas such as design of insulating systems (such as double-glazing) and designing buildings. Here is, probably, one of the first scientific experiments to look at this: wiki.nsdl.org/index.php/PALE:ClassicArticles/GlobalWarming/Article3
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Post by Acolyte on Mar 3, 2009 11:30:44 GMT
Could some one direct me to an experiment by any one which showed beyond reasonable doubt that carbon dioxide, or gases such as carbon dioxide absorbs or can absorb "energy" with the result that the atmosphere containing the gases, or the gas itself, becomes warmer? Thank you You have to go back a long way for the basic science. These days, properties of such gases are important in many different engineering areas such as design of insulating systems (such as double-glazing) and designing buildings. Here is, probably, one of the first scientific experiments to look at this: wiki.nsdl.org/index.php/PALE:ClassicArticles/GlobalWarming/Article3OK, you do know double glazing has to do with removing the gas content between two panes of glass... right? Can you explain how this has ANYTHING to do with an experiment showing how CO 2 can absorb energy & make the atmosphere or the Earth warmer? As it turns out we know one heck of a lot more about the past than they did back then. How do you think the above statement reconciles with the FACt that in the past temperatures have been lower while CO 2 has been MUCH higher & temperatures have been higher while CO 2 has been lower? And where does this absorption experiment measuere the re-emission from those gasses? Like computer modelling, some things work in theory but in the real world where there is no glass tube, the practical application fails to follow the model.
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Post by steve on Mar 3, 2009 12:13:57 GMT
Acolyte You do know that scientists and engineers spend a lot of time examining the detailed properties of as many materials as they can get their hands on. You do know that a general point stating the reasons why scientists would in all likelihood know something very basic is different from a specific point that says scientists do know a specific property of a specific thing. Or are you suggesting that there is a world-wide conspiracy of engineers NOT to examine the properties of CO2? For the reemission question look up Kirchoff's law of thermal radiation. As to your comments on the Tyndall paper, I'm providing an answer to a specific question, I'm not trying to use that paper to prove AGW theory. So don't imply that I am. You should already know the answer to the following. As it's not related to this thread I'm not going to answer it here. I suggest you start a new thread and also include in it a justification why the climate scientist's answer is wrong. Or admit that you don't know enough about climate science to understand the other side of the argument. PS. double-glazing typically contains argon. Thin double-glazing sometimes uses krypton and xenon, but these gases are expensive. I wonder if they've checked whether argon might be a greenhouse gas
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