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Post by nautonnier on Jun 1, 2009 14:56:25 GMT
I think that it is you that is reading the objection that you want into what I wrote. take multiple random models - say 30 of them all different but ALL claiming to be accurate models of the 'real world' the modelers that built them would defend them as such. Start them with random start parameters so none of them generate the same 'output climate' model. Now let them all use differing assumptions for minor issues such as convection and clouds - the one assumption that they must ALL have is that CO 2 will cause warming equivalent to 3.7Wm -2 for a doubling of CO 2. Now all the models generate differing climate outputs. When any attempt is made to validate the output SoCold chooses the model that nearly meets that validation test. Wrong, this entire issue is about falsifying the models based on a 10 year temperature trend not validating them. The question is, as I have repeated now many times, whether the recent 10 year flat period in temperature falsifies the models. Because some skeptics are saying the equivalent of "the models don't expect 10 years flat temperature". But that is wrong. I actually said that none of them show a DROP after a flat period. You then chose one that showed a flat period for 19 years and stated quite forcefully that it was good enough for climatological work. DESPITE IT BEING TOTALLY INCORRECT. If I generate a graph using my idea of climatology and can find _somewhere_ in the graph a pattern that nearly but not anywhere correctly matches what actually happened - I can claim that my model is as good as yours? There is no need to show any level of correctness - merely features that look similar on a graphical output for a mismatching temporal period? This is not my idea of modeling and validation although it is obviously yours.
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Post by dmapel on Jun 1, 2009 16:00:05 GMT
socold: "I didn't say anything about prediction, your "reply" to me is an offtopic non-reply. You might as well have written that in reply to someone else's post for all the relevance it has to my post. www.realclimate.org/index.php/arc....ng-term-memory/" So we have not been discussing the usefulness of the spaghetti to predict catastrophic AGW, that if they are to be believed would presumably necessitate the dismantling of the developed World's economy, to save us all from becoming TOAST. Despite it allegedly being an "offtopic non-reply", you were nonetheless compelled to scurry over to surrealclimate for your canned response. One might get the impression that you have been assigned by the team to haunt this board in an attempt to weakly defend the catastrophic AGW party line. A reply from the principal author of the paper to Gavin's BS can be found in comment #152 here: www.climateaudit.org/?p=3361It's a very interesting discussion that is very relevant to the discussion here. This comes from comment #87: "...In the beginning people thought of the climate as a deterministic system . The climate trajectory was supposed to be computable and predictable and inaccuracies were only due to the lack of computing power and crudeness of the parametrizations . After having multiplied the computing power by 100 - 150 in the last 10 years and the time spend on parametrizations by a similar factor , the models are still as inaccurate as they were and what increased is only the confidence that they indeed are inaccurate . This in itself is a powerful signal that there is a very fundamental error somewhere in the approach . If something like that had happened in a more serious scientific branch (like high energy physics f.ex) , people would have dropped the wrong methodology already long ago . The approach begins to slightly change now . First as there can be no trust in any individual model , the "ensemble theory" has been invented according to which every model gets "something" right (but nobody knows what) and something wrong (everything else) . By averaging the model results , the wrongness cancels out or at least reduces but the rightness stays . This theory seems to me silly and based on no serious physics . Second the modellers grudgingly abandonned determinismus and try to heal the problem by ergodicity . Schmidt even says that their models are "chaotic" showing hereby that he doesn't know what chaos is . What they try in fact is to handle the climate with statistics - while the evolution of every individual parameter that constitutes the climate can't be computed and predicted , the AVERAGES (time and/or space) of the said parameters are robust and significant while any difference between a realisation of the parameter and its average obeys some statistical law . That is the theory in which Realisation = Climate + Noise . It is analogous to Kolmogorov turbulence theory and that's why I guess Schmidt is calling that "chaos" . Of course any analogy stops here because the assumptions taken by Kolmogorov (homogeneity and isotropy) that give sense to his theory are absent from the climate theory . And of course , not surprisingly , according to D.Koutsoyannis and other work that begin to appear now the "healing" of the models by salvaging at least the time averages , fails too ..."
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Post by icefisher on Jun 1, 2009 16:01:42 GMT
There is no need to show any level of correctness - merely features that look similar on a graphical output for a mismatching temporal period? This is not my idea of modeling and validation although it is obviously yours. Socold obviously lives in that netherworld where no accountability exists. He no doubt thrives on people giving him somebody else's money because they think its a good idea in a universe where opinions are a dime a dozen. Its gotten sooo baaad that now even major corporations and billionaires are shuffling their feet to line up for it. To say that our way of life is in danger is a gross understatement. But never fear Shangria La is just over the next ridge and our solar powered jet running with an energy reserve of bowls of fruits, nuts, and bananas will get us there.
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Post by socold on Jun 1, 2009 18:39:05 GMT
Wrong, this entire issue is about falsifying the models based on a 10 year temperature trend not validating them. The question is, as I have repeated now many times, whether the recent 10 year flat period in temperature falsifies the models. Because some skeptics are saying the equivalent of "the models don't expect 10 years flat temperature". But that is wrong. I actually said that none of them show a DROP after a flat period. You then chose one that showed a flat period for 19 years and stated quite forcefully that it was good enough for climatological work. DESPITE IT BEING TOTALLY INCORRECT. Some of them do show a drop after a flat period, in that the trend is negative for 10 years or more. I didn't say it was "good" on these timescales. Quite the opposite. I have made it very clear that individual model runs are not expected to match actual climate trends on decadal timescales. Ie I don't expect the temperature over 10 year in a model run to match up with ENSO events in the temperature record. Real life might have an El Nino in the 5th year, wheras the model run has an el nino in the 2nd year for example. This is all irrelevant on multi-decadal timescales because the overall trends are less affected by the placement of ENSO events and other noisy variation. Your idea of validation is obviously to conclude modelled long term trends can be dismissed if individual runs don't predict a precise El Nino event at the correct time (I wonder if you would years back have written off models for not predicting the 1991 pinatubo eruption) So if for example all the models were run to see what happened if there was a massive 1% decrease in solar output per year, and all of them showed a robust result of significant (>1C cooling) cooling by 2050 and ice age conditions by 2100. Then you come along and dismiss this long term trend result that all the models show, just because you point out that none of the individual runs got the El Nino in 2005 spot on. Well that's a useless method of validating models.
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Post by socold on Jun 1, 2009 18:47:09 GMT
Socold obviously lives in that netherworld where no accountability exists. You have to be wary of incorrect falsifications though. Some people unfortunately seek iron cast falsification criteria for the sake of it. They don't consider the whole package of what the theory says, the possible errors in observation as well as in theory. They just jump right in to announcing because Bar X was breached, therefore the theory is falsified. We heard a whole earful from the creationists telling us that gaps in the fossil record falsified evolution. There were gaps, there still are some. They were a big problem for the theory and so the premature falsifiers jumped up and down screaming that the theory was falsified. But in the end it turned out that parts of the theory needed modifying (not even critical parts), not outright dismissal of the entire vast theory. If we had believed the premature falsifiers we would have incorrectly abandoned a valid theory for decades. The problem was that people were demanding a cast iron bar and if it wasn't reached they weren't just saying "this part of the theory needs revision" they were casting the whole lot out.
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Post by dmapel on Jun 1, 2009 19:52:11 GMT
OK, let's forget about the last ten years. What about the previous 3 billion years? When did CO2 ever cause global warming of 3-7C per century? Now don't hurt yourself rushing over to headquarters for the canned reply.
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Post by icefisher on Jun 1, 2009 20:22:58 GMT
You have to be wary of incorrect falsifications though. Some people unfortunately seek iron cast falsification criteria for the sake of it. They don't consider the whole package of what the theory says, the possible errors in observation as well as in theory. They just jump right in to announcing because Bar X was breached, therefore the theory is falsified. We heard a whole earful from the creationists telling us that gaps in the fossil record falsified evolution. There were gaps, there still are some. They were a big problem for the theory and so the premature falsifiers jumped up and down screaming that the theory was falsified. But in the end it turned out that parts of the theory needed modifying (not even critical parts), not outright dismissal of the entire vast theory. If we had believed the premature falsifiers we would have incorrectly abandoned a valid theory for decades. The problem was that people were demanding a cast iron bar and if it wasn't reached they weren't just saying "this part of the theory needs revision" they were casting the whole lot out. You are jumping to conclusions socold. I see a fundamental difference between falsifying a model and falsifying a theory. The basic theory of global warming is that the globe is going to get warmer with more CO2 in the atmosphere. The models portend to suggest how much, how soon. Now I made a living doing financial models and let me tell you its well accepted that prices keep going up. Any theory that says that home values next century are going to be higher than this century is accepted by a shrug. . . .so what. What modelers are hired to do is get a good estimate of how much, how soon. You won't have a job long if you mess up that latter part. You can run around shrieking your head off, waving your arms in the air about it being warmer in 2100 than now and nobody will care much. They will file that information away into something to keep in their mind while making choices for today. Of course the shrieking arm waver is doing all that because he has no faith in anything but himself; either that or he has seen something in the data that leads him to believe its irreverseable. But nothing, and I mean nothing could be further from the truth. For example, Walmart recently began a program of selling nothing but certified caught seafood. They didn't do this for altruistic purposes they did it because the common man has that in the back of his mind and makes some decisions about where he goes and shops and buys stuff. Nobody has yet been personally injured by indiscriminate seafood harvesting. People do this stuff because they think it is right. The private enterprise system actually works and it works to avoid stuff like bad stuff from global warming. The idea it is not irreversible is every bit as misguided. Technology is an amazing thing. Naysayers have existed from day one and yet technology, mostly coming from wealth and successful private enterprise, has overcome everything put into its path despite what the unimaginative pessimists have said over the centuries. Luddites have been there forever. I agree that if we could put a man on the moon in five years we can solve the issue of global warming also. I also don't think we get there by prohibiting people from driving on freeways or anything else like that. We got to the moon because we put private enterprise to work on the topic. Burning gasoline may well be the most important tool we had in solving that problem as it allowed our society to prosper and raise the money for the work on the solution.
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Post by socold on Jun 1, 2009 20:43:47 GMT
OK, let's forget about the last ten years. What about the previous 3 billion years? When did CO2 ever cause global warming of 3-7C per century? Now don't hurt yourself rushing over to headquarters for the canned reply. haha straight from one extreme to the other I see
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Post by tacoman25 on Jun 1, 2009 22:07:29 GMT
But you are pointing to one model, when the majority did not show that. Sure, you can always find outlier models...but that isn't what AGW science or the IPCC bases their predictions on. Therefore, if the majority of models are missing what is happening, I really don't see how that should increase our confidence in climate models or the IPCC. The decadal variation in the model runs is not expected to line up with the decadal variation in the temperature record. However we can ask "do the model runs with their overall warming trend show 10 year periods of flat temperature?". It doesn't matter when they show it. It doesn't matter if one run shows a flat trend in 2011-2021 and another shows a flat trend in 2005-2015 for example. All that matters is that they do exhibit flat trends over 10 year periods now and again despite the overall warming trend. For that reason we know that the models are compatible with 10 year periods of flat temperature. Therefore it cannot be argued that a 10 year flat trend in the actual temperature record falsifies the models. rankexploits.com/musings/2008/result-of-hypothesis-tests-very-low-confidence-2ccentury-correct/Not necessarily falsified, but statistically, they are really stretching the limits of credibility.
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Post by dmapel on Jun 1, 2009 22:35:33 GMT
socold: "haha straight from one extreme to the other I see"
You couldn't find any support in the last ten years, so I gave you billions of years to work with. Not enough, right?
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Post by nautonnier on Jun 1, 2009 23:25:03 GMT
There is no need to show any level of correctness - merely features that look similar on a graphical output for a mismatching temporal period? This is not my idea of modeling and validation although it is obviously yours. Socold obviously lives in that netherworld where no accountability exists. He no doubt thrives on people giving him somebody else's money because they think its a good idea in a universe where opinions are a dime a dozen. Its gotten sooo baaad that now even major corporations and billionaires are shuffling their feet to line up for it. To say that our way of life is in danger is a gross understatement. But never fear Shangria La is just over the next ridge and our solar powered jet running with an energy reserve of bowls of fruits, nuts, and bananas will get us there. "Then you come along and dismiss this long term trend result that all the models show, just because you point out that none of the individual runs got the El Nino in 2005 spot on.
Well that's a useless method of validating models."The reason for the dismissal is that all the models as shown in AR4 are now outside or very close to the IPCC error bounds. There is no explanation as to where the extra solar energy has hidden. But we are told to expect that outside our lifetime these climate models will magically be correct when the 'hidden heat' suddenly appears. In justification of this an ensemble of erroneous models that have the common assumptions no negative feedback and CO 2 doubled will cause 3.7Wm -2 warming. So unsurprisingly the spaghetti shows "long term trend result that all the models show" a relatively steady rise to between 2C and 6C above current temperatures. On this wobbly basis it is recommended that the entire world is turned into an energy poor wasteland that _will_ result in a whole lot more misery than just returning the Earth to the Medieval Optimum - during which there were no catastrophic floods in Venice, Amsterdam or London. You are convinced that is for sure - but you are now becoming one of a minority.
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Post by sigurdur on Jun 2, 2009 1:55:10 GMT
Yes SoCold is becoming a minority when it comes to climate. If the people who write and run these models worked for a private company, they would have been fired years ago for lack of performance. Yet, because most of these folks work for government, which reallly sticks in my craw, they are not canned and actually allowed to speak as an authority. Yet, in fact, they have no credibility anymore.
I do wish that government would just can the dumb asses who are so intent on gloom and doom, when in fact, humanity has prospered most when the temp is another 2-3C warmer than present. IF AGW was a fact, I would welcome it with open arms.
However, I must accept that it is garbage science even tho my heart wishes it were so. What a huge disappointment it has been for me.
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Post by socold on Jun 2, 2009 18:50:42 GMT
Yes SoCold is becoming a minority when it comes to climate. If the people who write and run these models worked for a private company, they would have been fired years ago for lack of performance. Yet, because most of these folks work for government, which reallly sticks in my craw, they are not canned and actually allowed to speak as an authority. If you removed them and replaced them you would be back to square one. The new batch of experts would reach the same position as the old, because the position the experts reach isn't about people it's about what the data shows. There's no evidence that temperature has been 2-3C warmer than present during the timespan of human civilization.
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Post by tilmari on Jun 2, 2009 20:28:17 GMT
Yes SoCold is becoming a minority when it comes to climate. If the people who write and run these models worked for a private company, they would have been fired years ago for lack of performance. Yet, because most of these folks work for government, which reallly sticks in my craw, they are not canned and actually allowed to speak as an authority. If you removed them and replaced them you would be back to square one. The new batch of experts would reach the same position as the old, because the position the experts reach isn't about people it's about what the data shows. There's no evidence that temperature has been 2-3C warmer than present during the timespan of human civilization. You forget the Holocene Optimum 8400-5200 BP or 6400-3200 BC when NH temperatures were at least that high. For example Scandinavia had a Mediterranian climate. Timo
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Post by sigurdur on Jun 3, 2009 4:37:12 GMT
You forget the Holocene Optimum 8400-5200 BP or 6400-3200 BC when NH temperatures were at least that high. For example Scandinavia had a Mediterranian climate.
Timo
That is the time frame I was referring to. Did I miss something lately in that we have not come close at all to those temps since that time frame?
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