Your description is for empirical or, at best, phenomenological models. Climate modeling is mechanistic…i.e., based on fundamental physics. There are some processes, like cloud formation, that occur on small length scales and must be treated phenomenologically. However, the parameters in them are generally adjusted to get some very basic things right. In fact, as has been pointed out, there are way more degrees of freedom than there are parameters in these models.
There are plenty of predictions that the AGW hypothesis has made that have been verified…including the general trend in global temperatures over the last couple decades. But, a lot of the most interesting tests are of individual features…such as how the atmosphere moistens in response to increasing temperatures, an issue that is very important in the context of the water vapor feedback that increases the warming response to increases in CO2.
Blake, if this is really all bad science, can you explain why it has won the support of the American Association for the Advancement of Science, the U.S. National Academy of Sciences, etc., etc. Do these organizations understand science less well than you do?
None of which seems to contradict what I posted. Yes I realise it was a dumbed down verison of complex prrocess, I’ve done enough modelling to know what I’m talking about. The fact remains: the models are specifically constructed for best fit to reality. To then say that partially demolishing the model lessens the fit to reality is a trite truism. It couldn’t have achieved otherwise. It doesn’t constitute an attempt at falsification.
As I specifically said above, and as you ignored, anyone in 1960 who accepted that the long term trend would continue would have made those predictions no matter what they attributed cliamte variance to. They are just predictions contingent on rising temperature, not contingenton AGW.
I’ll repeat, someone who notices the temperature is rising and then says the snow will melt and evaporation will increase is not making a prediction, they are making a postdiction. I suggest you go back to my previous posts and read where I’ve already discredited this cheap tactic.
This is either an appeal to authority or an argument from popularity. It doesn’t matter one whit if the AAAS, the NAACP and the NFL all support it. If it ain’t science then it ain’t science. There are no authorities in science and science isn’t achieved by self appointed organisations taking votes on the facts.
If this is science then show us the meaningful, falsifiable predictions made. Predictions that had to be true if AGW was true and that would not have been observed if AGW was not true. Not predictions that rely on already well established trends continuing. Not scattergun predictions where 12 are made and one came true. Actual predictions that could only be made based on AGW and where, if they didn’t come true, the author would have been forced to reject AGW.
If you can’t do that then there is no science here.
It was not only man made items, nor greenhouse gases:
In any case that was not the main point, the reason why that was brought in was simply to show it was not true at all to say that the computer models never had actual measurements or being the subject of experimentation.
You haven’t dumbed it down. You have completely misstated it. I have done modeling too but there are different types of modeling. The type you are describing is not that type that is being done. See the paragraph under “Principle 3” here for further discussion of the point of model testing.
Look, if you are going to make grandiose claims about an entire field of science not really being scientific and people making elementary mistakes of circular reasoning, you are going to have to provide actual evidence of this. Otherwise, you are just whistling into the wind.
You are missing the point which is that the models are based on known physics. The way for them to be wrong is for one of the atmosphere to behave differently than the models predict. If warming leads to more water vapor in the atmosphere then that water vapor is going to exert a radiative forcing due to its absorption of infrared radiation…There is no way around that.
Appeals to authority actually provide quite powerful evidence when the authorities are well-respected. The point is that you are claiming that it ain’t science because you don’t think it is science, just as the creationists claim that evolutionary theory is not science. Why should we believe your interpretation of what is and isn’t science when it disagrees with people who, unlike you, actually have some authority to pontificate on the subject?
Well obviously, with only one earth, we can’t do the sort of controlled experiment that would be most ideal. However, there is plenty of evidence that AGW is correct. The evidence comes from many different sources and I suggest reading the IPCC report for the exposition of it. In a nutshell:
(1) The AGW hypothesis is based on well-established physical principles and many of the individual principles can be testing. One example is the paper I gave you that tested whether the water vapor feedback is occurring as the models predict in a warming world.
(2) James Hansen made predictions for global warming over the next several decades back in like 1988. He had 3 forcing scenerios because he was not prescient enough to predict if there would be a major volcanic eruption and how the various levels of greenhouse gases will change. However, given that we now know what did happen in terms of forcings, we can go back and see how well his forecast did and the answer is that it did quite well.
(3) The eruption of Mt. Pinatubo provided a way to study how well the models could predict the dip in temperatures that occurred.
(4) There are plenty of ways that the model predictions can be compared to the warming that is occurring in order to determine attribution. For example, the geographic distribution of the warming, the altitude distribution (e.g., warming troposphere and cooling stratosphere), the resulting warming of the ocean. There is no way that the models can be “tuned” to fit all of these even if the modelers tried (which, for the most part, they don’t…since the few parameters they have to play with are used to determine some very basic things like seasonal cycles). And, in fact, some of the data that the models get checked against weren’t even measured at the time that the models were being developed.
It continues to amaze me that someone can come in and make vague assertions about a whole field of science being faulty and actually expect others to take his views very seriously!
jshore, welcome to the discussion. Unfortunately, this claim is absolutely not true. The modelers all say that their results are tuned to match the historical record. Any model that can be tuned is not based on fundamental physics … unless you’ve figured out some way to tune the fundamental physics.
Here’s an example. There were 19 climate models used in the Santer study on Amplification of surface temperature trends. Here’s a breakdown of the forcings that they included:
79% did not include mineral dust
74% did not include sulfate aerosol indirect effects
74% did not include sea salt
63% did not include organic carbon
63% did not include land use change
53% did not include black carbon
53% did not include volcanic aerosols.
42% did not include solar irradiance
37% did not include tropospheric and stratospheric ozone
Now, given that these models were successful in hindcasting changes based on such a wide variety of forcings, perhaps you could explain to us how they all are able to give a close match to actual conditions? Clearly it’s not because they are “based on fundamental physics”, if they were, they could not possibly all give correct answers.
Can you say “tuning”? … I knew you could.
Finally, you say “There are some processes, like cloud formation, that occur on small length scales and must be treated phenomenologically. However, the parameters in them are generally adjusted to get some very basic things right.”
Cloud formation is arguably the most important (and least understood) forcing. They are parameterized, but even then the match to reality is very poor. For example, the Giss folks themselves say that the GISSE modelGCM gives average cloud coverage as ~58%, compared to the reality of 69%. Why don’t they tune the model parameters to give 69% coverage, so that they would get the “basic things right” as you claim?
Because if they did, the model would then give very incorrect answers regarding historical temperatures. The models are not tuned to get the basic physics right, they are tuned to reproduce historical data. Since they are tuned to the outcome rather than the basic physics, it is a circular argument to say “the model much be correct, because when we remove one forcing it can’t reproduce the historical record.”
In addition, because of the tuning, it is meaningless to say “the model must be right because it can hindcast the historical record”. Well, d’uh, it’s tuned to reproduce the historical record, so that proves nothing.
Your claim would be believeable only if you could cite a prediction by the AGW folks that temperatures in the past two decades would rise in the first decade and level off in the last ten years. I know of none.
Again not true, the prediction of of the reaction of water vapor to atmospheric warming by the models has not been verified. The recent study by Wentz et al., “How much rain will global warming bring”, demonstrates quite clearly that the models do very poorly in predicting this important phenomenon.
Can you explain how the same support by a variety of scientific organizations for the theory that ulcers were caused by stress was shown to be entirely wrong? That’s a no-brainer … science, including science that is believed by a variety of prestigious scientific organizations, has been proven wrong countless times in the past. As I’m sure you know, your argument is a known logical fallacy called “Appeal to Authority”. From Wikipedia:
Of course no model is perfect, the important thing to keep in mind is that they are improving and continue to be tested as we speak, and even with the information available they already showed their value.
intention, I think you’re missing jshore’s point here. AFAICT, he is not claiming that a scientific hypothesis supported by a consensus of the mainstream scientific community can never be wrong. Of course a consensus view can be wrong, and that’s the reason that even theories supported by broad consensus need to be constantly re-examined and tested and critiqued and refined, to catch and correct whatever errors they may contain. jshore’s a research physicist, he understands that.
What he’s objecting to, I think, is the sweeping claim put forth by you and Blake that scientific research endorsed by all the leading scientific organizations doesn’t even count as science at all, and therefore may be totally disregarded. You and Blake are claiming not only that the AGW hypothesis might possibly be wrong (which nobody here disagrees with; we all know that any scientific hypothesis might be wrong, especially if it’s relatively new and has a lot of uncertainties in it), but that it doesn’t even qualify to be called science. Since jshore knows that the overwhelming majority of professional scientists and members of scientific standards bodies don’t agree with you on this, naturally he finds your attitude a little peculiar.
Now me, on the other hand, I’m ecumenical. As I said above, if somebody with an interest in a particular scientific field decides that the methodological standards accepted by professional researchers in that field aren’t good enough for him, and in fact he doesn’t think they’re even worthy of the name of science, my response is “Okey-dokey, whatever floats your boat”. I’m not a professional scientist, I’m a professional historian of science, and I study a variety of scientific traditions and cultures. If somebody decides to start a new scientific subculture by entirely repudiating certain standards and practices solidly accepted in the scientific mainstream, I don’t take umbrage, I take notes.
On the other hand, I have to admit that even my cheerful and tolerant relativism doesn’t prevent me from recognizing where the majority of these new revolutionary scientific subcultures tend to end up: on the trash heap of history, that’s where, being pawed over by us trashpickers of history.
Let’s face it, folks, the instances where a bold visionary genius utterly repudiates widely accepted scientific standards and practices, endures decades of marginalization and ridicule by the mainstream scientific community, and ultimately ends up proving them wrong and being gloriously vindicated are…pretty rare. The brutal truth is that the vast majority of bold visionaries who insist on utterly repudiating widely accepted scientific standards and practices ultimately end up being first marginalized and ridiculed, and then completely irrelevant, and then dead and forgotten. The ratio of heroic contrarian geniuses to mere contrarian crackpots is, alas, vanishingly small.
Personally, intention, I would be thrilled if you and Blake turn out to be heroic contrarian geniuses who end up massively reforming the practice of mainstream climate science and putting it on a revolutionary new methodological footing and making the NAS and the AAAS and the IPCC and all the rest of the alphabet soup agree with you on what is and is not “science”. I would be able to go around for the rest of my life bragging that I used to argue with you on message boards. Given the way the numbers generally run, though, I do have to recognize that the odds are high that you and Blake will simply turn out to be…well, er, the other kind of contrarian, the kind whose views don’t end up revolutionizing the scientific mainstream. Alas.
(And by the way, guys, I’m not sure your inspirational story about the etiology of ulcers is really analogous to developments in climate science. As best as I can make out, the hypothesis that ulcers are caused by the bacterium Helicobacter pyloriwas proposed by researchers Warren and Marshall only in 1982, and within fifteen years it was completely accepted in mainstream medical research and the CDC was launching a national education campaign to tell ulcer patients everywhere about antibiotic treatment. That was an example of a truly revolutionary contrarian triumph in mainstream science, and it didn’t take several decades to gain acceptance.
Skeptics of the AGW hypothesis in climate science, on the other hand, have been complaining about it for some thirty-plus years now, and still haven’t managed even to come up with an equally plausible alternative hypothesis, much less demonstrate that the AGW hypothesis is wrong. Now of course, that certainly doesn’t prove that the AGW hypothesis is true, or that the skeptics are wrong about what they consider the fundamental unsoundness of mainstream climate science. But the longer this situation continues with the skeptics remaining marginalized and the AGW hypothesis increasing in mainstream acceptance, the more probable it appears that the skeptics are indeed just…well, um, the other kind of contrarian.)
kimstu, this is far too basic to have a scientific paper written about it. It’s high school level math. Asking for a study of this is like asking for a scientific quote or a published research paper that shows that the top rung of a ladder is higher than the bottom rung.
However, because it is so simple, you can do it yourself. Take either of the datasets I linked to. Regress the MEI dataset on it. Remove the amount of the temperature dataset which is due to the El Nino. What’s left is the temperature adjusted for El Nino. That will allow you to check my work (I did it using HadCRUT3 temperatures) which you will find here.
If you can’t do that … then why are you in this discussion at all? If you don’t have that very rock-bottom level of knowledge, then you’re just parroting answers that you don’t understand and have no way of checking, you’re just making an appeal to authority without knowledge of your own. Why should we listen to you?
And if you can do that … why haven’t you done it as I requested in my post?
That one will do, I cited it because you were obviously familiar with it. However, you could also take a look at figure 2.1 here.
Idso’s 8 natural experiments gave the following values:
I took the more conservative estimate from these at 0.2, although you could certainly argue for 0.1.
I have read Gavin’s claim. Unfortunately, the “simple model” proposed by Gavin is too simple to represent the Earth. This is because the maximum amount of greenhouse warming possible under Gavin’s model is not enough to fit the known earth energy budget. Since the model cannot represent the earth, any conclusions that we can draw from it cannot be applied to the Earth.
But even if Gavin is correct, this only applies to one of the eight natural experiments (natural experiment #4). I have never read anyone who said that there was a problem with any one of the other seven natural experiments.
Look, I know mainstream scientists don’t accept the lower values … but then mainstream scientists are convinced of the CO2 hypothesis, and naturally disregard the other scientists who hold other views. When mainstream science can show that Idso’s other conclusions are wrong, then you’ll have a scientific conclusion. Right now, all you have is scientists ignoring another scientist’s work.
Seems like what you are trying to say is that if we only look at the work of scientists that believe in the consensus, that there is no fundamental debate … well, d’oh …
Sure. See the BBC distributed computing experiment here. Note that, unlike the other GCM runs, they have not excluded what they call the “unstable” runs, which are runs that show significant cooling. Note how many there are …
Of course, when they did their final analysis, they threw out all the runs that showed cooling because they were “unphysical” …
That’s not “how I feel about it”. I gave you two examples (particle physics and cold fusion) where the whole scientific community won’t accept computer runs as proving the existence of a new particle or cold fusion. I clearly asked if you thought those represented evidence.
I’m getting tired of you not replying to my examples and questions. You say that computer models show that global warming exists.
I asked if a computer model showing cold fusion would mean that cold fusion exists, and if not, why not.
I answer your questions. I’ve come back on my own in this thread to answer a question that I later noted was unanswered. Please show me the same courtesy. At present, the number of questions you’ve left unanswered is quite large.
You are using up entire hay fields here building straw men. Show me one place that I said that mainstream climate science is worthless.
I do think, however, that most of the climate models are worthless. You are 100% correct that there is, to use your words, no *“thoroughly well-understood physical model of all (or even most) of the features of global climate systems.”*Given that there is no physical model for global climate, we’d have to conclude that there is no valid computer model for global climate which is based on physical first principles.
You seem to think that because there’s only one earth and no well-understood model of climate, we must perforce use parametric models for things like determining climate sensitivity.
Didn’t you read the Idso paper? He presented 8 “natural experiments” that used real life data to determine sensitivity. Didn’t you read the other post I cited that provides an empirical method to determine sensitivity?
The idea that because there is only one earth our only option is to use climate models is all too typical of the shallow, one-dimensional thinking of “mainstream science” regarding the climate issue. There are many natural experiments we can look at, there is a host of real world data out there (not the best data, but data) to analyze, there are lots of phenomena to explain.
For example, you might take a look to see if you can find a study showing that the recent warming is anomalous. This should be easy to do without a computer, statistics was invented for questions such as this. Let us know if you find such a study.
I’ll get back to you when you have decided to answer the questions, this is far too one-sided for me.
Well, part of the answer is that many of those forcings are probably minor contributors…so that is why you can reproduce the historical record without them. Second of all, I don’t see the results of a comparison to the historical record so I don’t know how well it reproduced them. Are you claiming that the models that don’t include solar forcing or volcanic forcing nonetheless well reproduced the rise in temperatures in the early part of the 20th century? I’d be surprised to find this is so and I don’t see it claimed anywhere in Santers’ paper.
intention, extraordinary claims require extraordinary evidence. You are claiming that the whole field of climate modeling is contingent on circular reasoning whereby the reason that the climate models are successful in reproducing the historical record with greenhouse gases and not without is that they are tuned to reproduce the historical record with greenhouse gases and not without. This is quite an extraordinary claim and one for which you haven’t supplied any evidence outside of basically just saying that is how you believe it is done!
And, if it were done that way, then one would expect that someone who wants to support the thesis that greenhouse gases are not important could simply take a climate model and “tune it” to reproduce the historical temperature record without greenhouse gases and then show how the addition of greenhouse gases results in a worse agreement with the historical temperature record. I haven’t seen any example of this…Have you?
What is your evidence that temperatures have leveled off?
No…That paper says, “both climate models and observations indicate that the total water vapor in the atmosphere increases by about 7% K–1” so the two are in agreement on this point. The question of how well they predict precipitation, while interesting, is separate from the question of how well they predict moistening of the atmosphere and, from the point of view of the strength of the water vapor feedback, I don’t believe this is particularly important (although it does obviously have important implications regarding floods and droughts in a warmer world).
As kimstu notes, of course science is not infallible but usually the smart money is betting in favor of science and not against it. The fact that this one example with ulcers is cited again and again is evidence of this. (It is also worth noting that the ulcers thing is a bit more complicated than it is sometimes portrayed…While the “cause” of ulcers is now understood to be a bacteria, the fact is that this bacteria also lives in the guts of lots of people who never develop ulcers.)
Science is not always correct but it is the best arbiter we have for truth at the moment. And, I don’t really see an alternative to relying on the best science available to make policy decisions. The alternative that those who argue against climate change seem to implicitly subscribe to is that you rely on science when it agrees with your prejudices or political biases but that you don’t when it doesn’t. This is a recipe for the complete politicization of science bearing on public policy.
Well, you seem to jump on this one Idso paper as being definitive when it contradicts almost everything on the subject in the peer-reviewed literature. In fact, others who have looked at “natural experiments” to determine the climate sensitivity have reached very different results. See, for example, Jim Hansen et al’s recent paper here, or this paper by some experts in paleoclimate, or this paper that I cited above that looked at the experiment provided by the eruption of Mt. Pinatubo. The discussion in the latest IPCC report on observational constraints on climate sensitivity starts on p. 718 of this chapter [warning: 5.6MB PDF file!].
jshore, you’re not following the discussion, which is leading you to make foolish statements and raise straw men. I never said the Idso paper was definitive. I said that estimates of climate sensitivity ranged from 0.2 to 1.5°C/W-m2. I gave Idso and another paper (showing 0.3°/W-m2) as examples of the low end, and the IPCC values as the high end. Does that sound definitive to you? My point was that what Kimstu calls disagreements about the details are really about fundamental issues.
If the sensitivity is 0.2°/W-m2, CO2 rises make no significant difference at all. If it is 1.5°/W-m2, CO2 rises are important. This is therefore a billion dollar fundamental question, not a mere “detail” as Kimstu had claimed.
If the models don’t reproduce reality as you seem to be suggesting, then why on earth is Santer using them in his model?
And the forcings that you call “minor contributors” are certainly not thought to be so by the IPCC.
First, a bit of clarification. I don’t claim that the models “are tuned to reproduce the historical record with greenhouse gases and not without.” I am saying that the models are tuned to reproduce the historical record with greenhouse gases, and that an inevitable result of that tuning is that they will not then reproduce the historical record without the exact combination of forcings used when they were tuned, whether CO2 or some other forcing. The fact that models which use a different choice of forcings can all replicate the historical record shows that tuning is going on, and that it is tailored to the exact forcings used.
I don’t find the claim that the models are tuned to be at all extraordinary. It is well known that climate models are tuned to reproduce the past. For example, Gavin Schmidt says “Model parameters are tuned to improve the simulation of present day climatology.”
How much tuning is done?
Well, the GISS3 model has ~58% cloud cover, where in the real world it is ~69% … other model shortcomings include ~25% regional deficiency of summer stratus cloud cover off the west coast of the continents with resulting excessive absorption of solar radiation by as much as 50 W/m2, deficiency in absorbed solar radiation and net radiation over other tropical regions by typically 20 W/m2, sea level pressure too high by 4-8 hPa in the winter in the Arctic and 2-4 hPa too low in all seasons in the tropics, ~20% deficiency of rainfall over the Amazon basin, and a ~25% deficiency in summer cloud cover in the western United States and central Asia with a corresponding ~5°C excessive summer warmth in these regions. In addition to the inaccuracies in the simulated climatology, another shortcoming of the atmospheric model for climate change studies is the absence of a gravity wave representation, which may affect the nature of interactions between the troposphere and stratosphere.
Given the existence of these huge errors, errors ten times larger than a doubling of CO2, are you seriously claiming that the GISS model gives accurate results without tuning? And the tuning is not done to match the physical conditions as you claim, otherwise the GISS model wouldn’t contain the egregious errors listed above – the model would have been tuned to remove those errors.
Me, I don’t have either a climate model or a supercomputer to run it on. We’re talking megabucks here, both for the computer and the funding to run it. The people who have them have absolutely no interest in cutting their financial throats by showing that the historical record is due to anything other than CO2. I’m sure you’ve heard the saying “Absence of evidence is not evidence of absence”, and it goes double when financial questions enter the picture.
See my post a couple above this one … please follow the thread, jshore. When I’m asked to provide references to things that have been extensively discussed on this thread, it makes me cranky, and I haven’t had my coffee this morning.
I said “the prediction of the reaction of water vapor to atmospheric warming by the models has not been verified”. Since when is precipitation not a part of the reaction of water vapor to warming?
Again, this is a straw man. It has nothing to do with my “prejudices or political biases”. I disagree with the “scientific” claims being made.
Let me lay out for you how science usually works. Something catches the eye of some scientist, he or she notices some anomaly. Perhaps it’s that the orbit of Neptune doesn’t seem to be exactly where we think it should be.
The first step is to verify that there is actually an anomaly, that there is something out there that we should be concerned about. At that point, we can go out to search for reasons for the anomaly.
In order to verify the anomaly, the second step is to verify the data that we are using to describe the anomaly, to make sure that the anomaly actually exists. Once we have done those two things, we can be sure that we are dealing with an actual anomalous phenomenon.
So before going out to search for Pluto as an explanation for Neptune’s anomaly, first we need to determine if an anomaly exists.
Now, the first problem with climate science is that no one has shown that there is an anomaly. The modern temperature rise is neither longer nor steeper than the rises in the past. Record highs are no more common than we would statistically expect. I have asked this question many times of many people, without getting an answer - what statistical evidence do we have that recent temperatures are anomalous?
The second problem with climate science is that there has been no attempt to verify that the surface temperature data is accurate. As the recent work by surfacestations.org has shown, many of the so-called “high-quality” stations suffer from a variety of problems. Do these make the temperature trend appear to be warmer than it really is? We don’t know, do we, because no one has quantified the errors.
To summarize:
Is the earth warming? Well, some parts are, some are not. Overall, there has been a warming trend since the Little Ice Age. This trend has been fairly constant at about a half degree per century, and has continued up until the present day.
Is recent warming anomalous? I know of no statistical evidence that it is unusual in any way. There is no unexpected increase in the length or steepness of warming trends, nor any unexpected increase in record temperatures. People keep pointing to the fact that the recent temperatures contain the warmest years … but in a three hundred year period of generally rising temperatures, this is about as unusual as walking up a ladder and pointing to the fact that the recent rungs are the highest rungs …
Is the temperature record reliable? This is unknown, because there has never been a proper audit done of the stations themselves. The climate recording stations were never designed to measure increases in hundredths of a degree, so until very recently, proper care has never been taken to record microsite changes, instrument replacement, and the like. This increases the uncertainty of the measurements, and makes it very difficult to detect the kind of tiny changes we are looking for.
All of this has been made infinitely more difficult by actions like Michael Mann’s refusal to reveal his algorithms, Phil Jones’ refusal to say what stations are used in the HadCRUT3 temperature dataset, and James Hansen’s refusal to reveal the computer code used to convert raw temperatures into the GISS gridded temperatures.
Now, perhaps you’re willing to join the rest of the sheep when those folks say “trust me, I’m a climate scientist” … me, I’m not. I don’t trust “science” that is not transparent. I have this obsession with facts. You could start by showing me some facts that indicate that the recent climate is anomalous. I’m willing to be convinced, but by facts, not by consensus, not by models, and not by people who conceal their work. Where are the facts that show the temperature is anomalous?
intention: The IPCC estimates are not high end estimates…They are the best estimates of the climate science community. And, the Idso estimate is actually well off the low end of what the IPCC concludes to be realistic estimates.
We’ve discussed Santer many times before so I am rather surprised that you still don’t grasp the basic point of that paper. What they demonstrated was that even when they looked at a broad range of very different models (and ones that produced very different results at least for temperature trends over the relatively short period for which the satellite data is available), there was something that these models robustly predicted and that is the amplification of temperature fluctuations (over a range of timescales) as you go up in the tropical troposphere.
As such, the broader the range of models that they could use and still see this, the more robust the result.
I said that “many of those forcings are probably minor contributors” not necessarily all of them. (And whether they are minor or not also depends on what timescale one is looking over. E.g., solar forcing gave a significant contribution to the warming the first half of the 20th century but not in the second half.)
Well, since you have taken this quote out of context and don’t even say where you got it from, it is hard to comment exactly on it. However, I would say that it does not agree with your claim that the models have been tuned to reproduce the past historical global temperature trends. “Present day climatology” is not the same as past temperature trends and you well know that Gavin Schmidt would be one of the first to say that your claims here regarding how the models are or are not tuned are absolutely not correct.
This is bizarre logic. Somehow you are arguing that because there are things that the models don’t reproduce well, that somehow proves that they have been tuned to reproduce what you think they were tuned to reproduce. I would propose that instead what it shows is how little ability the modelers actually have to tune the models because they are highly constrained and because there is so many more degrees of freedom in the system than there are parameters in the models (and even the parameters that are not really “free parameters” but ones that can perhaps be varied over some limited physically-reasonable range).
Well, at some point those who are making outlandish claims about a whole field of science need to put up or shut up. Is there some grand conspiracy whereby the only people who are allowed access to the model are scientists who have pledged not to use it in a way that casts doubt on the AGW hypothesis?
Well, it is just that you are making a claim about the temperature record that I haven’t seen supported in any credible scientific study. It also seems to contradict your statements in previous threads where you have claimed that the temperature trend over periods of time of like a decade can’t even be determined with very much precision.
Read the paper and try to understand what it is saying. Their point is that getting precipitation right entails more than getting the amount of water vapor in the atmosphere right. It depends sensitively on winds, for example. Again, while it is interesting to try to understand why the models apparently are having some trouble accurately forecasting trends in precipitation, it does not bear on the question of whether they are reproducing the trends in water vapor correctly (which is what is important in regards to the water vapor feedback). That paper clearly notes that they are.
Well, I guess I have to spell it out. I used what the IPCC said was the high end of their estimate, where they said that sensitivity greater than 4.5 “could not be ruled out”. What about that is not a “high end estimate”?
Nor did I say that the Idso estimate, nor the two other estimates I provided, were within the IPCC estimates. I said, and I quote:
Do you see anything about the IPCC in there? You’re gonna run out of straw soon. I said scientists estimated that range. I have provided three separate scientific references to values below the IPCC range, which have been calculated from a variety of different methods.
In other words, everything in my original quote is 100% verified … and my original question, for which my original quote was only what I thought was a non-controversial claim, has never been answered.
So I have to congratulate you and Kimstu, jshore, you’ve totally spun the original question out of sight in a vain attempt to show that what every climate scientist knows (that the range of scientific estimates of sensitivity is extremely wide) is not so.
Whenever either of you wants to answer the original question, I’m sure that the majority of readers, who I suspect are not deceived by your attempted spin, might be interested in the answer. I used to be … but I’m growing tired of having to cite well-known facts while you guys tap-dance around while not answering the question.
intention: Yes, there are a wide range of estimates for climate sensitivity if you consider all of them that are out there. However, the question is what the likely range is…and, the IPCC considers it “very unlikely” (<10% chance) that the climate sensitivity is less than 1.5 C for doubling [or ~0.4 K per (W/m^2)]. So, the range may still be pretty broad but not so broad that we can’t conclude that it is very likely that we have a significant problem on our hands…even if there is still debate about exactly how bad it is going to be.
jshore, thank you for your post reminding me once again of the IPCC estimates. But ever since the IPCC considered it very likely that the Hockeystick was actually science, I fear I’ve lost any trust in their to distinguish between truth and fiction.
In addition, the IPCC action in the PPP versus MER debate was not only unscientific, but unethical and dishonest as well. Heck, these are people whose stated policy is that they will write the summary first, and then change the science to fit the summary.
Because of those and other IPCC actions (further details upon request), I fear that your statement that the IPCC considers it “very unlikely” (<10% chance) that sensitivity is less than 1.5°C per doubling means nothing to me.
(And as an aside, since the IPCC statement of likelihood is based purely on subjective criteria, that’s not science either …)
w.
PS - does this mean I don’t believe in any conclusions from mainstream climate science? Absolutely not. I just like to make scientific decisions the old-fashioned way … based on science and facts, rather than based on appeals to authority, whether the IPCC or anyone else.
