========================================================================= Date: 3 January 1996, 18:05:45 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? Rich Puchalsky posted (responding to Atomic Rod): >Why does the "green movement" dislike nuclear power? and: >Because all too many of its proponents combine extreme scientific ignorance >with arrogance, like the poster above. This is not a convincing explanation since the same could be said of many of nuclear power opponents as well. Actually there is no great mystery here, the green movement dislikes all technology and nuclear power is an easy target. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 January 1996, 21:07:29 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted: > Actually there is no great mystery here, the green movement >dislikes all technology and nuclear power is an easy target. Rich Puchalsky replied: >That's odd. I wonder why the "green movement" is so fascinated with >solar power and other relatively new energy-producing technolgies, then? >Or why they are always talking about the technology of EVs? I didn't say they dislike all technology equally. The green movement tends to prefer impractical technology since such technology is unlikely to be implemented on large scale. Solar power and EVs are attractive to the green movement because they are completely uneconomic (for widespread use) at present. When a technology such as wind power starts to become practical, the green movement suddenly discovers that wind generators are noisy, look ugly and kill birds. I believe at least a portion of the green movement (Sierra Club ?) initially supported nuclear power. Rich Puchalsky added: >Nope, your generalization fails. Well to be safe I probably should have said almost all. However I cannot think of any technology in widespread use that the green movement likes. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 10 January 1996, 20:54:03 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted in part: > The green > movement tends to prefer impractical technology since such technology > is unlikely to be implemented on large scale. Solar power and EVs > are attractive to the green movement because they are completely > uneconomic (for widespread use) at present. Tom Gray replied in part: >On the other hand, fusion is also completely uneconomic at present. >Why aren't environmentalists rushing to embrace it, if their support >is proportional to the degree to which a power source is uneconomic? Fusion is not just uneconomic at present, it does not exist at all. Greens prefer technology like solar which rich hobbyists can fool around with and that they can claim would be economic if only our economic system properly valued the environment. Not even greens can claim this for fusion with a straight face. You will note that the green movement is less hostile to fusion research than fission (especially breeder) research. This is because it is obvious that fusion research along current lines (tokamak) is not going to produce an economically viable reactor. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 10 January 1996, 20:56:40 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted: > Actually there is no great mystery here, the green movement >dislikes all technology and nuclear power is an easy target. Rich Puchalsky replied: >That's odd. I wonder why the "green movement" is so fascinated with >solar power and other relatively new energy-producing technolgies, then? >Or why they are always talking about the technology of EVs? I replied in part: > I didn't say they dislike all technology equally. The green >movement tends to prefer impractical technology since such technology >is unlikely to be implemented on large scale. Solar power and EVs Rich Puchalsky countered: >Your claim is disproved by this very newsgroup. You can hardly say that >the many "greens" who enthusiastically post here about solar power and EVs >dislike these technologies at all. Therefore your original claim, which >said nothing about large-scale use as a criterion, is disproved. Green support for technology such as solar power (to the extent that it exists, most posters to this group are not greens although they may agree with some green positions) is generally only as a lesser evil when compared to existing technology. I also posted: > However I cannot think of any technology in widespread use >that the green movement likes. Rich Puchalsky suggests: >This is silly. How about bikes? As has been continually pointed out >here, the chain-sprocket bike and the ICV were developed at about the same >time. I seem to recall someone in this very group (Mike V?) complaining at great length about the environmental harm bikes do. Greens may prefer bikes to cars, but they also prefer walking to bikes. Off road bikes are bad because they tear up the ground, destroy vegetation and allow more people access to back country. On road bikes are bad because they require roads and roads are bad. Furthermore manufacturing bikes requires mining iron ore, smelting it etc., all bad in green eyes. Rich Puchalsky continued: >I'm afraid that your desire to score a simplistic rhetorical point has >deprived your post of any real value. Not that I really expected a non- >rhetorical discussion of why "the green movement dislikes nuclear power" >on this forum. Your contribution of course was to suggest that greens oppose nuclear power because they find some nuclear supporters distasteful. This is both untrue and insulting to greens. I will amplify my argument. Asking why the green movement opposes nuclear power entails the implicit assumption that greens agree that nuclear power is less environmentally damaging than power from coal (otherwise the answer is obvious and the question is silly). Many greens will agree if pressed that nuclear is less damaging than coal. Nevertheless they oppose nuclear power, since to them the choice between nuclear and coal is like the choice Utah used to offer condemned men, to be shot or to be hung. The fact that most people given this choice will prefer to be shot does not mean they should favor being shot. The green movement dislikes technology because technology makes possible large scale industrial processes and the industrial revolution in general which the green movement considers evil because of its effect on the environment. Individual greens may not totally reject the industrial revolution, just as individual Catholics may not accept all church doctrine (such as the ban on divorce). This does not mean that it is not doctrine. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 12 January 1996, 20:01:49 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted: > You will note that the green movement is less hostile to > fusion research than fission (especially breeder) research. This is > because it is obvious that fusion research along current lines > (tokamak) is not going to produce an economically viable reactor. Scott Nudds asked: > If Tokamak isn't going to work, then why are so many right wing loonies >insisting that it will solve all of the worlds problems? Right wing loonies are as subject as anyone else to wishful thinking. Note also most people who suggest fusion as a possible future power source do not tie themselves to a particular design such as tokamaks. I am not ruling out all forms of fusion power, I am claiming the tokamak research program is not aiming towards a viable reactor design and is therefore a waste of money. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 12 January 1996, 20:03:43 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted: > Green support for technology such as solar power (to the >extent that it exists, most posters to this group are not greens >although they may agree with some green positions) is generally >only as a lesser evil when compared to existing technology. Rich Puchalsky replied >This is gettting rather tiresome. First, you'll have to define what *you* >mean by "green", if it doesn't have the accepted colloquial definition. >Does only a current member of the Green Party count? Once you've done that, >then tell us how you have special insight into what "green"s beleive. Are >you one? I am using green to refer to green beliefs in their purest and most extreme form. The purest form of green beliefs will seem extreme to most people since these beliefs will be based on green values alone. Most people have other values as well and will take these into account even when they share the green values. I believe the core green belief is that the natural world should not be disturbed. In this formulation humans are not considered to be part of the natural world (otherwise you can argue anything humans do is natural and ok). So what distinguishes humans from other species? In my view it is technology, hence my statement that greens dislike technology. I am not a green (obviously) nor do I claim any special insight into their beliefs. This does not bar me from commenting on them. You freely comment on libertarian beliefs although you (presumedly) are not one. When you do so, you also appear to be referring to those beliefs in their purest and most extreme form. I also posted: > Individual greens may not totally reject the industrial >revolution, just as individual Catholics may not accept all church >doctrine (such as the ban on divorce). This does not mean that it >is not doctrine. Rich Puchalsky commented: >And who created this doctrine? Where is it written up? I feel so >un-indoctrinated now that I know that there is a Green Bible and Green >Priests that I've been missing out on. Like libertarians, greens have no single bible or founding father. I do not feel like trying to put together a green reading list as the green philosophy is not of much interest to me. I posted: > Your contribution of course was to suggest that greens >oppose nuclear power because they find some nuclear supporters >distasteful. This is both untrue and insulting to greens. Rich Puchalsky responded: >Nope, not at all. I'd hardly want a complex and potentially dangerous >piece of equipment like a nuke power plant run by people who are both >arrogant and scientifically ignorant (my original claim). Your original post referred to nuclear "proponents" not to nuclear plant operators. In any case, I doubt requiring nuclear plant operators to pass the Puchalsky tests of modesty and scientific competence would alleviate green opposition. Or are you arguing that running a nuclear power plant requires inhuman amounts of modesty and scientific competence. Also the safety argument against nukes is not really a green argument. Instead it is an argument of a group I would call Naderites (safety nazis is an alternative name) which have a distinct set of values. Nuclear plant accidents do not really pose a major threat to the biosphere, in fact it has been noted that the area around Chernoble (sp?) is reverting to a more wild state now that humans are largely excluded. I also posted: > The green movement dislikes technology because technology >makes possible large scale industrial processes and the industrial >revolution in general which the green movement considers evil because >of its effect on the environment. Rich Puchalsky replied: >Oh, nonsense. Greens want "appropriate" technology and "sustainable" >development. "Appropriate" technology basically means better technology. Ok, what large scale industrial processes do greens consider to be appropriate technology? How much of the technology that the US or world economies is based on do greens consider to be appropriate? What is an appropriate technology for China to use to increase its production of electrical power? I think you are being disingenuous here. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 19 January 1996, 21:20:40 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? Rich Puchalsky posted: >I see. You're creating a strawman, in other words. No. Consider for example the anti-abortion movement. It thinks abortions are bad. Nevertheless most members of the movement would allow abortions in some cases, such as to save the life of the mother. Only the most extreme anti-abortionists would seek to prevent all abortions. Similarly the green movement thinks disturbing the natural environment is bad. However most would allow some disturbance, the amount depending on how extreme they are. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 19 January 1996, 21:21:49 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Scott Nudds posted: > Heating can only produce one effect. A temperature increase. How big >a temperature increase is a legitimate matter for debate. But the fact >that the average temperature will increase is a scientific fact. > > It should be noted however that we are talking about average >temperatures within the range of stability. If the range is exceeded, >the climate can drastically change state - altering modes so to speak. >In this case, we have insufficient information to state the direction of >the nearest local maximum/minimum that the climate will be pushed to. Michael Tobis has repeatedly made a similar claim. It is wrong, feedback can reverse the sign of the response of a system in a stable equilibrium to forcing. Below is an example which shows this which I have posted before. > This is wrong, feedback can reverse the sign of an output. >Consider the following system: > > y'=B*y with y= y1 B= -4 3 > y2 -2 1 > >The eigenvalues of B are -1 and -2 so y1=0, y2=0 is a stable equlibrium >solution of this system. Now introduce positive forcing on y1 ie > > y'=B*y+a with y= y1 B= -4 3 and a= 1 > y2 -2 1 0 > >The new stable equilibrium solution is easily seen to be y1=-.5, y2=-1. >The exact solution with initial conditions y1=0, y2=0 at time t=0 is > > y1= 2.*exp(-t) -1.5*exp(-2.*t) - .5 > y2= 2.*exp(-t) -1.0*exp(-2.*t) -1.0 > >Hence although the initial impact of the forcing is to increase y1, >the interaction with y2 causes the eventual impact of the forcing on >y1 to be negative. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 19 January 1996, 21:23:06 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming R. T. Pierrehumbert posted some time ago: >Yah, it is clear that Halliwell is right about everything here, and >Shearer makes as little sense when talking about climate models as he >did when talking about feedback systems. R. T. Pierrehumbert posted recently: >Most of what jwas has posted in this discussion is nonsense, but >I caution the participants that arguing that it is "physically >impossible" for increasing CO2 in a "stable" system is not >really tenable. One can cook up possible (though implausible) >scenarios under which temperature reductions, measured by >some criteria, are possible. The "positive response" theorem >can be proved for only certain types of feedbacks, which depend >on atmospheric temperature in certain restricted ways. In other words I was right and Tobis, Halliwell and now Nudd were wrong. Feedback can reverse the sign of the response of a stable system to forcing. R. T. Pierrehumbert posted some time ago: >I honestly hope I don't sound patronizing, but I think Shearer is >learning something from these discussions. ... Pierrehumbert appears to have learned something, we will see about Tobis, Halliwell and Nudd. R. T. Pierrehunbert also posted: >It is not necessary to argue at that general level of abstraction, >though, since many mathematically possible things are not >physically plausible. Climate science has included many >feedbacks that could moderate or amplify the CO2 warming, and >none of them reduce temperature in response to CO2 increases. >These are all based on tested physics. > >If somebody claims that temperature might go down in response >to increasing CO2, the onus is on him to propose a specific >physical mechanism and show how it works. A statement that the temperature is likely to go down in response to increasing CO2 might require this, a statement that it has not been proven that the temperature won't decrease does not. Physical intuition is fine but it is sometimes wrong. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 22 January 1996, 23:20:08 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming R. T. Pierrehumbert posted: >For the record, Shearer is quoting me out of context, and in other >places putting an unjustified interpretation on what I said. > >I am disappointed that he is more interested in the appearance of >having scored points than he is in a serious discussion about >climate sensitivity. Well, if Pierrehumbert doesn't want people trying to score points off him, he should avoid making rude and insulting posts like the one I quoted (not out of context btw). However in the interests of serious discussion let me ask a question. Climate modelers worry about reflection of visible light (shortwave radiation). What about reflection of longwave radiation? Is this a completely unimportant process? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 22 January 1996, 23:21:20 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? I posted: > No. Consider for example the anti-abortion movement. It > thinks abortions are bad. Nevertheless most members of the movement > would allow abortions in some cases, such as to save the life of the > mother. Only the most extreme anti-abortionists would seek to > prevent all abortions. > Similarly the green movement thinks disturbing the natural > environment is bad. However most would allow some disturbance, the > amount depending on how extreme they are. Rich Puchalsky responded: >Bah. After your invocation of Godwin's Rule, I don't know whether I >should bother. But it's obvious that the two cases are not comparable. >It is possible to have a functioning human society with absolutely no >abortions (at least, legal ones). It is not possible for humans to live >without disturbing the natural environment. Therefore, according to your >strawman, greens want everyone to die off. This is manifestly untrue; >"green" thought is concerned with creating new technologies and techniques >that will allow humans to disturb the environment without destroying >natural systems. The most extreme greens do want to see humans die off (or at least give up technology returning them to natural status). As I stated before most people have many values which they trade off between when they conflict. Few people whether greens, libertarians or antiabortionists exclude all other values. The fact that these beliefs rarely occur in pure form does not mean it is impossible to say what the pure form would be. It is not apparent to me that greens have any interest in creating new technology in any practical sense. Greens tend to like new technologies only so long as they remain safely impractical. Rich Puchalsky added: >But I should expect ridiculous claims like this from people like Shearer >who like to call people they don't agree with Nazis. I made a passing reference to "safety nazis" a term which I did not invent and which does not mean Nazi. Puchalsky appears to prefer distorting what opponents have said to making substantitive responses. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 25 January 1996, 20:38:26 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Reflection of longwave radiation I asked > However in the interests of serious discussion let me ask >a question. Climate modelers worry about reflection of visible >light (shortwave radiation). What about reflection of longwave >radiation? Is this a completely unimportant process? Dave Halliwell responded: > Where? Surface? Atmosphere? > > In the atmosphere, reflection of longwave radiation is basically >"completely unimportant". If you really _are_ interested in a "serious >discussion", then you will elaborate on the question so that I can >explain _why_ it is "unimportant". Consider a simple 1-d radiative model with a slab atmosphere. Clearly if either the surface or atmosphere (including clouds) reflect longwave radiation then this will affect the energy balance equations. However it appears usual to omit these terms. Is this because they are very close to zero or is there some other reason? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 25 January 1996, 20:39:45 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: climate models Halliwell and I have been discussing a simple climate model which I posted some time ago. I will split my reply to Halliwells last post into several parts (posted as time permits). Dave Halliwell posted: > I was using Ha=0.5, and He=1.0, but there was an error in my >spreadsheet formulae (a relative instead of a fixed cell address). > > When the error is corrected, I find the system of equations to be >stable, so my original analysis of instability was incorrect. (I reduced >Ha to 0.005 and He to 0.01, with a time step of 1, which is equivalent >to leaving Ha and He at 0.5 and 1.0 and reducing the time step to 0.01). This is a good illustration of one reason why I am skeptical that large complicated climate models have much value. Even if you stipulate that the physics of the model is correct there remains the question of how you can be confident that the model has been correctly implemented on the computer. It is almost impossible to debug a large computer code when you don't know what the correct answers are. The model Halliwell and I are discussing is trivial compared to current large climate models. Yet Halliwell's first attempt to implement it was incorrect. In this case the error was detected because I did a completely independent implementation of the same model and obtained different results. I doubt very many of the current large climate models have been implemented independently by several groups. I suspect if this were done routinely it would often uncover bugs. There are psychological factors involved also. If the program results match what the implementer expected he is likely to search less vigorously for bugs than when the program results are unexpected. This creates a bias which may cause results of several groups to converge to a faulty consensus. (This has been observed to occur in the determination of physical constants by several groups.) James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 26 January 1996, 21:53:13 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Dave Halliwell posted: > If Shearer doesn't want people making "rude and insulting" posts, then >he should stop making statements about climatology that only demonstrate >his ignorance on the subject. If climatologists feel free to be rude and insulting to anyone with an imperfect knowledge of climatology they should not be surprised if the public declines to heed their advice or support their work. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 26 January 1996, 21:54:23 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: climate models I continue to respond to Halliwell's comments on a model I posted in which feedback reverses the sign of the response to forcing. Dave Halliwell posted: > If you examine the time series for either Ta or Te, you find that >either will oscillate back and forth about the equilibrium value, >gradually getting closer to equilibrium. (Again, rather than >cluttering up the text of this post with data, I will append a >portion of the results to the end of this post.) The system is very >_slow_ to approach equilibrium, and a great number of oscillations >are required. The example at the bottom of this post starts out 1 degree >warmer than equilibrium (for both Ta and Te), and shows oscillations >with an amplitude considerably _larger_ than the initial perturbation. >The system _amplifies_ the initial perturbation. > > What does this mean? It means that Shearer has described an AC >system, and not one in which a DC electrical analogue is appropriate. >The original position, as described by Tobis and supported by myself >and Pierrehumbert is that the climate system is one in which DC >analogues are appropriate. In such a system (DC), feedbacks >CANNOT reverse the sign of a forcing. Shearer's assertion to the >contrary is still just an assertion. > > In AC systems, a perturbation leads to responses which alternate >in sign over time. The concept of feedback "reversing" the sign >of the perturbation doesn't mean the same thing when the >perturbation's sign is time-dependent. > > All Shearer has done is show that he can't tell the difference >between AC and DC systems. You appear to be a bit confused. The perturbation we are interested in is directly heating the surface (say by a network of nuclear power stations). This is introduced by changing the equations (adding the f term in my previous posts). This forcing term is not time-dependent and therefore has an unambiguous sign. Changing the equations changes the position of the equilibrium. If the system starts at the old equilibrium when the forcing is turned on it will converge to the new equilibrium. Therefore as time goes to infinity the response has an unambiguous sign relative to the original equilibrium. In this example Te (the temperature of the surface) will decrease, a response of opposite sign to the forcing, which is the point of the example. As for your complaint that the system approaches equilibrium in an oscillatory fashion, I don't see what this has to do with anything. However if it bothers you, you can look at the system with Ha/He =.1 which does not. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 26 January 1996, 21:56:05 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming I posted: > In other words I was right and Tobis, Halliwell and now >Nudd were wrong. Feedback can reverse the sign of the response >of a stable system to forcing. Dave Halliwell responded: > ...and your examples (from the one presented under "climate models" >late last year, to which I will respond shortly) presented so far, fall >outside the realm of DC analogues, to which the "feedback reversal" >comments have applied. Tobis in his original posts didn't qualify his claim to DC analogues. If my simple examples fall outside the realm of DC analogues why should anyone believe that it is certain that the much more complex climate system falls within that realm? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 29 January 1996, 23:10:21 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Why do the green movement dislike nuclear power? The "safety nazi" discussion continues: Mark Frisel posted: >I understood the phrase to refer to those who approach safety issues >using techniques and attitudes associated with the German NAZI movement. >If I misunderstand, I urge Mr. Shearer to state exactly what the phrase does >mean. Scott Nudds asked: > If the term "safety nazis" is not intended to mean "nazi" then why is >the word "nazi" part of the phrase? The same reason "czar" is part of the phrase "drug czar". In recent years "nazi" has acquired an idiomatic alternative meaning when used in the formation "x nazi". It means someone with strong or fanatic views on subject x (and sometimes also someone who wishes to impose those views on others). Hence a "safety nazi" is someone with strong or fanatic views on safety and who may wish to impose those views on others. Compare "health nazi", "food nazi", "soup nazi" etc. This alternative meaning of "nazi" is not the same as the original meaning but it is not totally unrelated either. Frisel's understanding is not completely wrong but in my view it is too strong. I would say the new meaning derives from the fact that the Nazis had fanatical views which they wished to impose on others. However the term "soup nazi" is pretty far removed from the Nazi movement. Rich Puchalsky posted: >I will leave the reader to decide who is distorting what is said and who >is making substantive responses. I freely admit that *this* particular >response doesn't contain any substantive science; Shearer has already >invoked Godwin's Rule, after all. OK, my original usage of "safety nazi" was as follows: > Also the safety argument against nukes is not really a >green argument. Instead it is an argument of a group I would call >Naderites (safety nazis is an alternative name) which have a distinct >set of values. Nuclear plant accidents do not really pose a major >threat to the biosphere, in fact it has been noted that the area around >Chernoble (sp?) is reverting to a more wild state now that humans are >largely excluded. Puchalsky concluded from this that: >But I should expect ridiculous claims like this from people like Shearer >who like to call people they don't agree with Nazis. Which I continue to believe was a substantial distortion of what I said. Incidentally, I do not totally disagree with the Naderites about nuclear plant safety. While I do not believe the risks are as great as the Naderites claim, I believe there are substantial safety issues and that some nuclear supporters are a bit cavalier about safety. Those nuclear supporters might consider me to be a "safety nazi". James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 29 January 1996, 23:12:19 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Flux correction Scott Nud posted: >Josh Howlett (jh5765) wrote: >: Even with what you have written, I still have problems with the flux >: corrections. Even if the corrections allow the models to more accurately >: predict today's climate, I find it hard to understand how you can realistical >: justify extrapolating into the future with these, given that they are >: compensating for some process(s) which aren't being modelled either accuratel >: or at all. > >From Scientific American Jan 94 >-------------------------------- > >Lies, Damned Lies and Models >---------------------------- >-Paul Wallich- > >
What point are you trying to make here? Is the fact that economic models are lousy supposed to increase our faith in climate models? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 29 January 1996, 23:13:13 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted: > As for your complaint that the system approaches equilibrium >in an oscillatory fashion, I don't see what this has to do with >anything. Dave Halliwell responded: > ...which suggests that you don't understand the distinction between AC >and DC systems. In AC systems, the question of phase (and phase lag) is >critical. It's easy to get a response that is out of phase with the >forcing, causing an apparent "reversal". In DC systems, there is no such >thing. You mean like in the climate system the seasons are out of phase with solar insolation. At this point I am going to have to ask you to define AC and DC systems. Please explain in detail why the climate system with its periodic (ie AC) forcing is a DC system while my example with its constant (ie DC) forcing is an AC system. I continued: >However if it bothers you, you can look at the system with >Ha/He =.1 which does not. Dave Halliwell responded: > The system with Ha/He=0.1 is still an AC system. Take a look at how it >responds to a _transient_ pulse of surface heating. I used He=0.01 and >Ha=0.001, with a time step of 1. Turn on "f" for _one_ time step, and >watch what happens: first Te increases, then decreases _below_ the >original equilibrium, then increases again, etc., oscillating in ever- >decreasing amounts around the original (=new) equilibrium. Not exactly. Te increases at first. It then decreases until it moves below the original equilibrium Te (at timestep 30). It then starts to increase again but it never returns above the equilibrium Te, instead it approaches the equilibrium Te from below. It does not oscillate around the equilibrium Te in "ever-decreasing amounts". James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 31 January 1996, 20:16:04 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Dave Halliwell and I continue to argue about feedback. I posted: > Tobis in his original posts didn't qualify his claim to >DC analogues. Dave Halliwell responded: > At at least one point, yes he did. Obviously you were not paying >attention. (Either that, or you didn't understand the distinction.) A citation would be helpful. I remember Tobis babbling something about the zero frequency limit but that is all. I don't think he claimed my example was AC (although he at first claimed it wasn't a feedback system, a claim which he eventually withdrew). A cursory search of his posts did produce the following. In a post dated July 26, 1995 Tobis said in part: >Dr. Pierrehumbert's point, by the way, is consistent with mine: the paleo >record actually shows an oscillation in temperature due to NADW >shutdown. This doesn't contradict the linear zero frequency feedback >approximation which allows for *oscillatory* cooling and warming in response >to a forcing that ignoring feedbacks is known to cause a warming. All the >argument says is that at some time after the forcing stops changing >the long-term mean change accounting for feedbacks will be of the same sign >as that neglecting feedbacks. This appears to rather directly contradict the argument you have been making on his behalf. Of course in this post Tobis also claimed my example was "in no sense a feedback system" so perhaps the above has become inoperative as well. If Tobis is lurking in this discussion he could clear some of these points up himself. He has been promising to refute my example real soon now for months. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 31 January 1996, 20:17:51 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted (regarding large complicated computer models): >I suspect if this were done routinely it would often uncover bugs. Dave Halliwell responded: > Here we have it: Shearer is so determined to reject the idea of >CO2-induced warming that he dismisses over 30 years of work by hundreds >or thousands of researchers in climatology as "bugs in the code". This is untrue. I do not reject the idea of CO2 induced warming. Some time ago I posted the following to this group: > I will assume your questions are based on a hypothetical >2*CO2 atmosphere. I will admit that this group of experts expects >some global warming to occur and that there appears to be about as >much expert support for major warming as minor warming. > For what it's worth my current estimates are: > sensitivity < 0 - 1% > sensitivity < 1.5C - 30% > 1.5C < sensitivity < 4.0C - 60% > 4.0C < sensitivity - 10% >These estimates are not firmly held and are subject to change. I >would be interested in the estimates of other posters. These are not the figures someone "determined to reject idea of CO2-induced warming" would give. I do not believe I have posted anything rejecting the idea of CO2-induced warming. I suggest Halliwell substantiate his claim or withdraw it. I had continued: > There are psychological factors involved also. If the program >results match what the implementer expected he is likely to search less >vigorously for bugs than when the program results are unexpected. This >creates a bias which may cause results of several groups to converge >to a faulty consensus. (This has been observed to occur in the >determination of physical constants by several groups.) Dave Halliwell responded: > Of course, Shearer is the only person that isn't affected by bias. I have never claimed to be unaffected by bias. I claim everybody is affected by bias, sometimes in quite subtle ways. Some pervasive ways in which people are influenced by bias are the following: 1. People tend to believe what it is in their interest for others to believe. For example that an auto accident was not their fault. 2. People tend to interpret new information in terms of a preexisting mental model. They are reluctant to discard a model before the evidence against it becomes overwhelming. For example a pilot may fly a plane into a mountain while thinking he is somewhere else entirely. He will have incorporated what might seem like ample cues that something is wrong into his erroneous mental model of where he is. 3. People tend to adjust their opinions so as not to stray too far from the opinions of their peers. For example analysts estimates of company earnings cluster more tightly than justified by the actual predictability of such earnings. (Ie the actual earnings are often far outside the range of expert opinion.) Scientists can try to minimize the effects of these biases on their work. However in my view they can never be entirely successful. Furthermore a blind denial that potential problems exist does not inspire confidence. Dave Halliwell continue: > Regardless of what anybody comes up with in the way of scientific >evidence supporting CO2-induced warming, Shearer is going to reject it as >"bug-ridden" or "biased". He's got his head stuck in the sand. This is again untrue. I accept that what is popularly called the "greenhouse effect" warms the surface of the earth. I accept that CO2 is a greenhouse gas. I accept that the observed increase in the CO2 content of the atmosphere is almost surely of anthropogenic origin. I accept that there is a plausible argument that increasing the CO2 content of the atmosphere will increase the magnitude of the greenhouse effect thereby warming the surface. I accept that simple climate models allow crude estimates of the amount of warming that can be expected. I reject (or at least am extremely skeptical of) claims that very elaborate climate models requiring large computer codes to implement allow (or will allow anytime soon) us to significantly refine estimates of climate change due to CO2 available from simpler models. I believe it is the people suggesting such models be used to evaluate policy options who have their heads stuck in the sand. Consulting the entrails of a goat would be as sensible. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 2 February 1996, 20:15:34 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do William M Connolley posted (regarding a 1971 paper by Rasool and Schneider): >1. the temperature increase with CO2 found is about 1/3 of Manabe and Wetherald >This is accounted for by different CO2 abs coeffs, different lapse rate specs, >and different CO2/H20 overlaps. So, who was right? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 2 February 1996, 20:16:15 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Dave Halliwell and I continue to argue about feedback. We are now discussing who said what when. Dave Halliwell posted: >[On or slightly before Jan 15, 1995, quoted by someone] > >In <3f6e6g$fmr@minotaur.nofc.forestry.ca>, Dave Halliwell >(dhalliwe@nofc.forestry.ca) wrote: > >: Keep in mind that the presence of many oscillators at various >: frequencies and delay times also means that one cannot assume a simple >: DC-type feedback response. It _may_ be possible that an initial warming >: could lead to _cooler_ temperatures at some time in the future, due to >: the relative strength and timing of various feedbacks. It is generally >: not thought that this _will_ happen, but it isn't a 100% bet. I do not remember seeing this post of yours. You seem to agree here that feedback can under some circumstances reverse the sign of the response to forcing and that this could be true of the climate system. I am puzzled then as to why you have been defending Tobis's claims to the contrary. You quoted an example of one such contrary claim (11/29/95): >I do not make quite so strong a claim. I claim that *feedback* cannot >reverse the sign (at least in a sensibly linearizable situation) of >the system without feedback. That is, if the output is temperature, there >is no temperature-dependent phenomenon which can reverse the sign of >the response. This is a very solid result in elementary systems theory. There is no restriction to DC systems in this claim. I had posted: > I don't >think he claimed my example was AC (although he at first claimed >it wasn't a feedback system, a claim which he eventually withdrew). Dave Halliwell responded: > In the post I quote above, he does explicitly state that he doesn't >think it is a _linear_ feedback system. As I noted he withdrew this statement. The first post you quoted was from July 1995. On 9/16/95 Tobis posted in part: >It is a feedback system, granted. (I doubt he ever intended to deny the system is linear, since it clearly is.) I had posted: > If Tobis is lurking in this discussion he could clear some of >these points up himself. He has been promising to refute my example >real soon now for months. Dave Halliwell responded: > You, on the other hand, have never bothered to post any implementation >of the time dependence of your earlier example, nor have you made any >attempt that I have seen to demonstrate that your system fits the >restrictions discussed in Tobis' first post [of the ones quoted above]. As noted above, Tobis later seemed to agree that my example did meet his conditions. For example in the same 11/29 post quoted above: >At first glance, Shearer's counter-example seems to contradict this. >I intend to figure out why. As for posting the time dependence of my example, this seemed unnecessary since I posted the exact analytic solution. However to please Halliwell, I post some points of the time evolution of the example below. The system in question is y'=B*y+a with y= y1 B= -4 3 and a= 1 (when T>0) y2 -2 1 0 Recall the system starts in a stable equilibrium at (0,0). We introduce positive forcing on Y1 at time T=0. This initially causes Y1 to increase. The increase in Y1 causes Y2 to decrease. The decrease in Y2 causes Y1 to decrease. This negative feedback through the interaction with Y2 eventually forces Y1 below 0, opposite the direction of the forcing. The system converges to a new stable equilibrium with Y1=-.5 (and Y2=-1.). Feedback has reversed the sign of the response to forcing. Here columns 2 and 3 are the y1 and y2 variables. These are computed from the exact solution. Columns 4 and 5 are the y1 and y2 variables computed from the equations (Euler's method with step .1d0). exact numeric T Y1 Y2 Y1 Y2 0.000000 0.000000 0.000000 0.000000 0.000000 0.100000 0.081579 -0.009056 0.100000 0.000000 0.300000 0.158419 -0.067175 0.190000 -0.054000 0.400000 0.166647 -0.108689 0.197800 -0.097400 0.500000 0.161242 -0.154818 0.189460 -0.146700 1.000000 0.032756 -0.399576 0.036296 -0.410017 1.100000 -0.000463 -0.445061 -0.001228 -0.458278 1.500000 -0.128420 -0.603527 -0.140994 -0.623402 2.000000 -0.256803 -0.747645 -0.274141 -0.768376 2.500000 -0.345937 -0.842568 -0.362087 -0.860198 3.000000 -0.404144 -0.902905 -0.417075 -0.916456 4.000000 -0.463872 -0.963704 -0.470638 -0.970571 5.000000 -0.486592 -0.986570 -0.489714 -0.989707 6.000000 -0.495052 -0.995049 -0.496408 -0.996408 8.000000 -0.499329 -0.999329 -0.499563 -0.999563 10.000000 -0.499909 -0.999909 -0.499947 -0.999947 James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 February 1996, 19:49:09 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming The feedback discussion continues. Michael Tobis posted: >I think that it is unrealistic either in physics or in >engineering to find or construct a system with an unbounded >response to a finite input. If that's correct, then my statements, >including my DC limiting analysis and the similar analysis >in Peixoto and Oort's _Physics of Climate_ (American Institute >of Physics, 1992; pp 26 ff.) hold with the implicit restriction >that the individual elements of the system be themselves stable. > >However, I confess that I am not spectacularly certain that this >restriction is justifiable within limited ranges of a linearized >system. Provide me with a counterexample and I'll provide you with >a whole-hearted retraction. It is not justified. Almost any system at an unstable equilibrium will have a corresponding linearized system with the property that small displacements can grow exponentially with time. Consider for example an ideal pendulum consisting of a rigid rod attached to a pivot at one end. This has an unstable equilibrium with the pendulum stationary and directly above the pivot. Let x be the angular displacement of the pendulum from the vertical position. This system can be linearized by approximating sin(x) by x. The linear system has an exponentially growing response to most small perturbations. However the system is not physically unrealistic. The response eventually leaves the region where the linear approximation is valid and the exponential growth does not continue. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 February 1996, 22:39:40 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I had posted: > William M Connolley posted (regarding a 1971 paper by >Rasool and Schneider): >>1. the temperature increase with CO2 found is about 1/3 of Manabe and Wetheral >>This is accounted for by different CO2 abs coeffs, different lapse rate specs, >>and different CO2/H20 overlaps. > > So, who was right? Paul Farrar replied: >We'll know some time next century, when CO2 doubling is achieved. >Later we'll find out what happens at 2-1/2X, probably 3X, and maybe >4X. Perhaps in about 1000 years, when CO2 comes to equilibrium with >the oceans, we'll have the final answer on this practical experiment. You misunderstand my question. I am not asking who was right about the behavior of the real climate system, rather I am asking who was right about the behavior of the 1D RCM model of the real climate system. Len Evens replied in part: >Well in science one can never be absolutely certain who or what is >right or wrong. However, the general consensus, which includes >among other people Schneider, is that Manabe was closer to being >right than Schneider and Rasool were. ... Closer to being right about the behavior of the 1D RCM model? Len Evens continued: >However, this is really a rather silly question, I think. 1971 >is at this point ancient history. If you read the Rasool and Schneider >paper you would see that the analysis used there is quite rough and >uses a model of the earth very unrealistic according to present >standards. Manabe, also, was of course working with primitive >models, but it is interesting to note that his predictions for >temperature sensitivity to CO_2 doubling have remained fairly consistent >over this period of time. Perhaps, he and his colleagues, have had >good physical intuition about what is important and what is not. Since this is an old dispute about a simple model I would expect that it is now known exactly who was right and why. If this is not the case I would question what climatologists have been doing for the last 25 years. It is pointless to fool around with much more complicated models if you don't know what the correct absorption coefficients for CO2 are (for instance). So I ask again, who was right and why? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 February 1996, 22:40:39 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted: > I reject (or at least am extremely skeptical of) claims that > very elaborate climate models requiring large computer codes to > implement allow (or will allow anytime soon) us to significantly > refine estimates of climate change due to CO2 available from simpler > models. I believe it is the people suggesting such models be used > to evaluate policy options who have their heads stuck in the sand. > Consulting the entrails of a goat would be as sensible. Josh Halpern asked: >Does this also apply to the econometric models which are used for >budgeting purposes by CBO, OMB, etc, which have even greater impact >on policy options and the models used for program trading which >have enormous impact on our economic well being (well, at least >my hoped for retirement income)? If so, what is your position >as to the posturing in Washington over whose budget proposal is >honest? If you hold the econometric models to be useful, then >why are they more useful for policy decisions than the GCMs. The >later appear (at least to me) to be based more on knowledge than >the former. I don't trust any elaborate computer model that can't be convincingly validated. As I have posted before in this group this certainly includes many econometric models. Josh Halpern continued: >As you might guess, the purpose of asking you this question is to >point out that most policy decisions today are based on models, >and comparatively the Global Climate Models are based on a lot >better data and knowledge than the economic models that we depend >on. I don't agree, I believe most policy decisions today are based on politics. Josh Halpern concluded: >Almost without exception, policy decisions are made in the absence >of perfect (or even good) knowledge of the future consequences of >that action, and, as has been pointed out elsewhere, not to >decide is to decide. It is true that often important decisions have to be made in the presence of uncertainty. Policy makers find agonizing over such decisions painful. For this reason they are often very susceptible to claims that there is a way to reduce or eliminate the uncertainty. In ancient times this might involve consulting an oracle. Today it might involve running an elaborate computer model. In my view the value added is often about the same. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 9 February 1996, 23:38:40 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models Here I reply to a post of Rich Puchalsky in which he takes exception to my using errors in computer calculations by Dave Halliwell as an excuse to expound on the hazards of buggy computer calculations in general. I also respond to Halliwell's comments on Puchalsky's post. Rich Puchalsky posted: >Here Halliwell takes time, purely out of the goodness of his heart, to >actually set up a spreadsheet to test one of Shearer's propositions. No >publication is expected; no special rigor is desired for this off-hand >Usenet-inspired little task. Yet when Halliwell makes an error setting >up the spreadsheet -- which anyone could make, given the non-importance >of the matter and therefore the lack of careful checking involved -- >Shearer has the *gall* to hold this up as analogous to the work of >professional modellers that has been checked and reviewed prior to >publication in a journal. While posts to this group are not the same as publication in a professional journal, they may well be seen by as many people. In my view this means posters should take some care about what they post, particularly when they are declaring another poster was wrong. It is true anyone can make programming errors. (This is because writing correct programs is hard, much more so for the more complicated climate models than for the simple model Halliwell attempted.) However not everyone has Halliwell's blind faith in computer calculations. In the case at issue Halliwell declared my mathematical argument showing stability was invalid based on a numerical calculation in which the temperature of the earth went from 306.6 K to -2659.8 K in one time step. A more humble individual might have considered this as an indication that he was doing something wrong and looked for bugs. Finally many published papers dependent on computer calculations are not in fact checked in any meaningful way prior to publication. If Puchalsky thinks the results of buggy computer programs never make it into published papers, he is extremely naive. Puchalsky continued in part: >This kind of crap has to be contributing to the exodus of scientists from >sci.environment. I note that Pierrehumbert just posted that he no >longer has time to participate; Grumbine also recently left. I'll refrain >from going through the full list. I have never attempted to drive anyone out of this group by vilifying them. I wonder if Puchalsky can say the same. Dave Halliwell posted: > Not only that, but it's _Shearer's_ model. I was implementing the >model because his original post did not examine the overall >time-dependence of the system, from initial conditions to equilibrium: he >only looked at the initial trajectory and the final equilibrium value. > > In a "publication" analogy, Shearer is complaining because the reviewer >didn't do a perfect job of completing work that the author failed to >provide. Most reviewers would probably just pull out the REJECT stamp, >and not bother going into detail. Ok, let us consider a publication analogy. I submit a paper showing (using mathematical arguments) what conditions are needed for a certain simple model to have a stable equilibrium solution. Halliwell, as reviewer, rejects the paper based on his totally bogus numerical calculations which indicate instability. Eventually I convince the reviewer that he is wrong. However he still doesn't accept the paper. Instead he invents a new and equally spurious ground (that a discussion of under what conditions a model has a stable equilibrium is obligated to include a description of the trajectories leading to the equilibrium) for rejecting it. At this point I would be justified in asking the editor for a different reviewer. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 13 February 1996, 21:31:25 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming The feedback discussion carries on. Michael Tobis posted: >I'm beginning to be worried that I get the crow. I'm considering a >strong curry sauce, with lime pickle. However, I'm still having a hell of >a time figuring out how to use the pendulum in a system of springs and >dashpots such that applying a clockwise torque on something will make >it move counterclockwise. Or something like that anyhow. It's puzzling. > >I certainly don't buy into your first example with hydraulics, which >essentially had the flux over a dam proportional to its height. Actually my example essentially had the flux through a pipe at the bottom of the dam proportional to height of the water above the pipe which is more reasonable. Note the model only needs to be valid near the old equilibrium. Do you really doubt that it is possible to contrive examples with the desired behavior? Consider for example a house with a single zone heating system and the thermostat in a cold spot. Then it may be that the colder it gets outside, the hotter the house will be on average (since the thermostat will keep the cold spot at the desired temperature and the difference between the hot parts and cold parts of the house will increase as it gets colder outside). James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 16 February 1996, 22:06:22 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming The feedback discussion drags on. I had posted: > Do you really doubt that it is possible to contrive examples > with the desired behavior? Consider for example a house with a single > zone heating system and the thermostat in a cold spot. Then it may be > that the colder it gets outside, the hotter the house will be on > average (since the thermostat will keep the cold spot at the desired > temperature and the difference between the hot parts and cold parts > of the house will increase as it gets colder outside). Michael Tobis replied: >This has the nature of Steinn's example - you have more than one >variable. The temperature at the thermostat is insensitive to the >temperature outside and that's the only simple feedback loop. It >ought to be possible to use your pendulum with springs and dashpots >to accomplish the same with only a single output. It would be a very >interesting contraption, too. So I'm still puzzled. I thought your objection to Steinn's example was your claim that it would involve a nonlinear regime shift. In my example with a two room house we can have a completely linear system. Suppose T1 is the temperature of the room with the thermostat, T2 is the temperature of the other room. Cooling the outside tends to reduce T1 and T2, but reducing T1 may cause T2 to increase so much that the net effect is a warmer house on average. If we change variables so that S1=(T1+T2)/2 and S2=(T1-T2)/2 then we can arrive at a system of differential equations similar to those I have posted before. We force S1 down but the interaction with S2 causes S1 to eventually rise. Certainly one can imagine mechanisms whereby heating one part of the earth causes cooling elsewhere (without a regime shift). So I am puzzled as to what you think remains of your claim. The problem with trying to construct an example using springs is that springs act symmetrically. For example suppose the ends of the spring are A and B. Then if moving A to the right pushes B to the right, moving B to the right will pull A to the right. So this is a positive feedback loop and we need a negative feedback loop. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 16 February 1996, 22:08:17 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I have been asking about different predictions for the 1D RCM model in a 1971 paper by Rasool and Schneider and an earlier paper by Manabe. Michael Tobis replied in part: >I don't know whether anyone will answer your question, but that is not >because it is in principle unanswerable. I think that if you intend to >cast aspersions on the discipline as a whole, the lack of a clear answer >to the question you pose is lousy evidence. It's a question of infinitesimal >significance which 25 year old paper is closer to current understanding. I think in evaluating how much to trust current models it is worthwhile to see how well older models have held up. In this particular case I find the factor of three difference in model sensitivity suspicious. I wonder if R&S really checked that the factors mentioned account for the difference in model results. Could it be that the footnote was added at the last minute to pacify a referee and that the real explanation was something else? For example one might suspect a bug in one of the computer codes. Michael Tobis continued in part: > ... And of course, the >less objectively decideable question of lapse rate specification is >irrelevant to 3 dimensional models. The big models having replaced a few arbitrary assumptions (such as the lapse constraint) in simple 1D RCM models with a much larger number of arbitrary assumptions. I do not see why this should be considered an improvement. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 16 February 1996, 22:10:30 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models Scott Nudds posted: > For this reason alone, programming error as the source of warming in >models is a virtual impossibility. Warming is not the issue, simple models predict warming. The issue is whether programming errors could affect predictions of things like the amount of rainfall in Kansas in the more complicated models. Btw I doubt that "all models produce essentially same results" for things like that. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 20 February 1996, 21:18:39 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Scott Nudds posted (quoting Andy Holland): > Feedback can and will reduce the warming that has and will continue to >occurr. This is the nature of "stable" systems. They must have some form >of negative feedback. But no system of negative feedback can be expected >to exceed the very effect that it is resisting. > >: Global cooling, global warming, or global no change are the possible >: outcomes of greenhouse gases. > > Global cooling is only possible if the climate shifts to a drastically >different mode of operation that is far removed from the current mode. This is untrue as I have posted many times before. Feedback can reverse the sign of a response to forcing in a linear system (without a regime shift). A simple example is a two room house with a single zone heating system. If the thermostat is in the less well insulated of the two rooms, then it can occur that the average temperature of the house increases as the outside temperature decreases (because the increase in temperature in the hot room is greater than the decrease in temperature in the cold room). However the system remains in the same mode of operation throughout, contrary to your claim above. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 20 February 1996, 21:19:33 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming Scott Nudds posted: > Yes, and natural temperature fluctuations will already have moved the >state of the system to this new position if it had existed. Since >climate has been "stable" for a rather long time, we must conclude that >natural variability is not sufficient to move the climate to this new >state and therefore raising the temperature within the extremes we have >already observed will not cause a state change. You consider flipping in and out of ice ages stable? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 20 February 1996, 21:20:30 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models The discussion of the reliability of complicated climate models continues. I had posted: > Warming is not the issue, simple models predict warming. Scott Nudds responded: > If "Warming is not the issue" then I take it that you are now in >agreement that warming will take place? Previously you had held the >position that there was no evidence for warming and that the models could >not be trusted. > > Have you changed your position? You will not be damaged for admitting >to having done so. Nudds is misstating my previous position. As I posted a few weeks ago when Halliwell misstated my position: > This is again untrue. I accept that what is popularly called >the "greenhouse effect" warms the surface of the earth. I accept that >CO2 is a greenhouse gas. I accept that the observed increase in the >CO2 content of the atmosphere is almost surely of anthropogenic >origin. I accept that there is a plausible argument that increasing >the CO2 content of the atmosphere will increase the magnitude of the >greenhouse effect thereby warming the surface. I accept that simple >climate models allow crude estimates of the amount of warming that >can be expected. > I reject (or at least am extremely skeptical of) claims that >very elaborate climate models requiring large computer codes to >implement allow (or will allow anytime soon) us to significantly >refine estimates of climate change due to CO2 available from simpler >models. I believe it is the people suggesting such models be used >to evaluate policy options who have their heads stuck in the sand. >Consulting the entrails of a goat would be as sensible. As I have previously indicated one reason I am skeptical of large models is that it is hard to be sure that the large computer codes on which they rely are bug free. I had continued in my later post: >The issue is whether programming errors could affect predictions of things >like the amount of rainfall in Kansas in the more complicated models. Scott Nudds replied: > Don't fret. You can pretty much guarantee that any predictions with >this level of detail are significantly wrong in these details. Fine, we agree on this. So where is the value added (relative to simpler models) in the large complicated models. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 21 February 1996, 08:40:02 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I posted: > The big models having replaced a few arbitrary assumptions > (such as the lapse constraint) in simple 1D RCM models with a much > larger number of arbitrary assumptions. I do not see why this should > be considered an improvement. Scott Nudds replied: > I doubt if any of the assumptions are "arbitrary". Although I have >little doubt they would appear "arbitrary" to a layperson such as yourself. By arbitrary, I mean any assumption for which reasonable alternatives exist given the present state of knowledge. I would expect that the large models contain hundreds of such assumptions. William Connolley commented: >This statement is dubious. >Take something like albedo. In the 1-d models, there is just a number for surfa >albedo. In a GCM, there are seperate numbers for ocean, land, seaice, >and landice. In turn, each of these can depend on temperature, moisture, etc. >Now, the 1-d models single albedo number subsumes all these seperate numbers. D >that mean the single number is better? No. Its just hidden the complexity. The >albedo model cannot be modified in any physically based way in response to mode >climate change. The GCM numbers are more physically based and change in a physi >based way in response to climate change. Calling this "arbitrary" is unwise. All right, what would you call assumptions for which reasonable alternatives exist given the present state of knowledge? How many such assumptions do you believe a typical large climate model contains? How much of the space of reasonable alternative large climate models has been explored? Why should any great weight be given to a single point in the space of reasonable large climate models? James B. Shearer (email jbs@watson.ibm.com) PS: Sorry about the duplicate post in the climate models thread. ========================================================================= Date: 29 February 1996, 12:07:44 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Civility Rich Puchalsky posted: >My response pretends to ignore the smiley and "agree" that Nudds is a nice guy. >I often find this to be an effective response to a slam. In this case, I'm >trying to make the point that, although Nudds can indeed be rude, he at least >will read references and the like, and doesn't spew the same misinformation >over and over like his opponents do. I consider repeatedly spewing >misinformation to be a far less civil act than rudeness. Well actually in at least one case Nudds has been spewing the same misinformation over and over. He has repeatedly claimed that it is impossible for CO2 forcing to produce a cooler earth without a regime shift. This is untrue as I and several other posters have attempted to explain to him. A recent example of this is the following Nudds post (from the "Global cooling or warming???-to Nudds" thread) replying to Howlett: > I'm sorry Josh, the possibility of cooling is zero. The earth will not >cool through heating. Unless - the atmosphere enters a different mode of >operation which is outside the natural fluctuations observed. And in >this case, the average temperature will either be much warmer or much >cooler than it is today. Very bad news in any case. Note also that a regime shift does not require a significant change in average temperature as Nudds claims. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 11:13:43 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Half life of global warming William Connolley posted >In article 41@almaden.ibm.com, jshearer@VNET.IBM.COM writes: >> Scott Nudds (oh Lord, no!) posted: >>> ...Since climate has been "stable" for a rather long time... >> You consider flipping in and out of ice ages stable? > >This rather depends on your definition of "a long time". Is 1000y a long time? >so, SN's point is a fair one. First if you are going to annotate my posts, please make it clear what is my original post and what is your comment (in this case the interjection "(oh Lord, no!)"). Second the climatology defenders in this group have repeatedly claimed that it does not matter if weather is chaotic since climate is average weather and the time averages of chaotic systems can be predicted. However this is only true if we average over periods of time sufficiently long for the averages to approach their asymptotic values. So I will ask the climatology defenders in this group, how long do you believe is sufficiently long? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 11:36:16 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted: > As I have previously indicated one reason I am skeptical of > large models is that it is hard to be sure that the large computer > codes on which they rely are bug free. Scott Nudds responded: > Bugs occurr at random, and can be expected to produce random errors. >Presuming that these random errors do not cancel themselves out, would >you mind telling us how many models, all of which you must think contain >bugs, give essentially the same result? First bugs do not occur random and cannot be expected to produce random errors. Second the models do not in my opinion produce essentially the same result. What is the result you claim all the models produce? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 11:37:15 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I posted (here assumptions refers to assumptions for which reasonable alternatives exist): > How many such assumptions do you believe a typical large climate model > contains? Scott Nudds replied: > Another improper question since it is based on the assumption that >these assumptions exist. Actually it makes no such assumption. The concept of "zero" was discovered some time ago, perhaps you should acquaint yourself with it. You can claim no such assumptions exist in large climate models if you wish to make a complete fool of yourself. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 11:38:46 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I posted: > All right, what would you call assumptions for which reasonable > alternatives exist given the present state of knowledge? How many such > assumptions do you believe a typical large climate model contains? How > much of the space of reasonable alternative large climate models has > been explored? Why should any great weight be given to a single point > in the space of reasonable large climate models? Joshua Halpern commented: >A more interesting question is how sensitive the results are to either >arbitrary assumptions, or uncertainties in parameters. Although I >am not familiar with GCMs, the combustion and atmospheric chemistry >models I am familiar with carefully include a sensitivity analysis >The "key" values then tend to get measured, or improved quickly, >so that at least is a functioning positive feedback loop. > >In many cases an arbitrary choice, or a good guess, or an order >of magnitude estimate suffice. Well if the results are not sensitive to the details of the albedo submodel (for example) then it would appear pointless to have a complicated albedo submodel. I agree that a sensitivity analysis is important. I am not convinced that climatologists are doing an adequate job in this area. Note also that the more complicated the model the harder it is to understand what it is sensitive to, another reason I am skeptical of large complicated climate models. As for whether things are improving, consider the following quote from the paper "Climate Sensitivity" (by Robert E. Dickinson, in Advances in Geophysics, volume 28 (1985), Issues in Atmospheric and Oceanic Modeling Part A Climate Dynamics, p. 99-129, quote starts p. 110) "It would also appear that proper modeling of high-latitude cloud cover and its optical properties is important for obtaining a correct description of ice-albedo feedback in GCM simulations [as also in energy balance models, e.g., Golitsyn and Mokhov (1978)]. Unfortunately, even the climatological cover of high-latitude clouds is poorly known [as reviewed by Barry et al. (1984)], and their modeling in GCMs is totally speculative. Thus in summary it appears that the largest sources of uncertainty for the sensitivity of global average temperature to external changes in tropospheric energy balance are the magnitude of the ice-snow albedo feedback processes and the magnitude and sign of cloud-radiation feedback processes. These conclusions have been drawn for over a decade [cf. e.g., Schneider and Dickerson (1974)]. However, what is especially distressing is that recent GCM studies have not contributed to narrowing our uncertainty as to those processes but have suggested that we are rather more ignorant than we previously thought. ... " James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 11:40:44 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphe I posted: > The big models having replaced a few arbitrary assumptions > (such as the lapse constraint) in simple 1D RCM models with a much > larger number of arbitrary assumptions [*]. I do not see why this should > be considered an improvement. William Connolley commented: >This statement [the one with a "*" above] is dubious. >Take something like albedo. In the 1-d models, there is just a number for surf >albedo. In a GCM, there are seperate numbers for ocean, land, seaice, >and landice. In turn, each of these can depend on temperature, moisture, etc. >Now, the 1-d models single albedo number subsumes all these seperate numbers. >that mean the single number is better? No. Its just hidden the complexity. The >albedo model cannot be modified in any physically based way in response to mod >climate change. The GCM numbers are more physically based and change in a phys >based way in response to climate change. Calling this "arbitrary" is unwise. William Connolley further commented in a later post (I have reformatted to make the lines shorter): >You don't seem to have answered my point, >that replacing one number that covers >a great number of assumptions with many numbers >each physically simpler and more >amenable to measurement, theory and prediction *is* an improvement. It is not necessarily an improvement, it may well be worse. The more complicated the model is, the harder it is to understand how model will behave and what it is sensitive to. This complexity means errors may go undetected and lead to bogus results. In the case of albedo, I have no faith in complicated albedo models like those you describe. I do not see how they can be adequately validated. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 12:04:58 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Civility I posted: > Well actually in at least one case Nudds has been spewing the >same misinformation over and over. He has repeatedly claimed that it >is impossible for CO2 forcing to produce a cooler earth without a >regime shift. Scott Nudds replied: > Unless you employ feedback in the form of actions by little green >space men who are upset at a growing level of CO2 in our atmosphere, no >feedback mechanism can exist that will produce cooling. Quite simply, >warming can not cause average cooling. Although it can increase the >magnitude of natural temperature variation. > > Those who claim otherwise have the burden of prooving their statements. > > Provide a model, or admit that you can not do so. I have posted several examples which show that your statement that "no feedback mechanism can exist that will produce cooling" is false. There are linear systems in two variables with a stable equilibrium such that forcing a variable, say x, in the positive direction causes the equilibrium to move to a new position in which x is less than its value in the original equilibrium. In other words, feedback can reverse the sign of the response of a variable to forcing. Since it is not true in general that feedback cannot reverse the sign of a response of a system to forcing, the burden is on you to show that this is impossible in the case of the climate system with CO2 forcing. Otherwise you should stop claiming that it is impossible. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 4 March 1996, 19:54:55 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Michael Tobis posted: >As for Mr. Schneider's doubts regarding computer models, basing his >experience on ecological population models is misleading. The mathematical >basis for those models is in crude mathematical representations of >enormously complex behaviors of individual members of species which >interact in enormously complex ways. Climate, on the other hand, though >it presents very complicated behaviors, is based on immutable physical >laws that are known with astonishing precision. It does not, of course, >follow that the implementations perfectly represent those laws in practice, >but it does facilitate the testing of those models, and it also allows >for far greater confidence that the models as specified represent the >real situation. In my view it is this response which is misleading. Climate may be based on immutable physical laws, however climate models are based on approximations to these laws, in many cases completely empirical approximations in no way derived from the underlying physical laws. I recently obtained a "Description of the NCAR Commumity Climate Model (CCM2)" from the net (gopher://isis.cgd.ucar.edu/99/ processor/doc/TN-382.ps.). Some quotes p. 46: "... and h is a meridionally varying, empirically derived local liquid water scale height currently evaluated as h = A+B cos (4.a.13) with A=1080 and B=2000. ..." p. 47: "... repeatable solar year of exactly 365 days ..." p. 48: "... surface albedos in the model are not known to an accuracy of better than 1-2% of solar insolation ..." p. 48: "This approximation has been shown to simulate quite well the effects of multiple scattering." p. 49: "... the cloud droplet effective radius is fixed at 10 m ..." p. 50: "The cloud extinction optical depth () is modified as: = A and A is the fractional cloud cover in the layer; the power 3/2 was found necessary to give results approximately the same as the random overlap assumption." p. 64: "A seasonally varying snow cover that depends only on latitude and month is prescribed. ..." p. 67: "... the number of layers is arbitrary. ... we arbitrarily chose a constant layer thickness of 50 cm." p. 67: "We assume the physical depth of the snow is 10 times its liquid water equivalent depth." p. 77: "There can be a problem ... may result in negative values for C, which are not removed by the subsequent implicit diffusion step. This problem is not strictly numerical; it arises under highly non-stationary conditions for which the ABL formulation is not strictly applicable." p. 96: The radiation parameterization also requires that surface albedo be specified on the model grid for land points. The land albedos are constants (independent of time or moisture conditions); land albedos for snow-covered points are weighted values of snow albedos and constant land albedos depending on snow depth and local roughness length. ..." This is not what I would call "astonishing precision". Any confidence that such models "represent the real situation" would appear to be a product of faith rather than of logic. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 March 1996, 20:26:31 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do Michael Tobis posted: >I wonder whether Shearer's skepticism regarding such models extends to >models of the atmospheres of other planets, or the dynamics of stars, >or even to the pursuit of fluid dynamic modelling of industrial processes, >all of which are undertaken in an essentially similar way. As I have said in previous posts, I am extremely skeptical of any computer model which cannot be easily checked against reality. Consider the comments of Clifford Stoll regarding his dissertation (which depended on a computer model of Jupiter's atmosphere) in his book Silicon Snake Oil (p152-153). "Yes, but do I believe it today? That question makes me squirm. Complicated computer models are sexy--researchers manipulate their views of reality to fit their favorite computer program. They become invested in their own models. After years of modeling Jupiter's atmosphere and exploring parameter space, I'm not certain. I spent months researching what ought to go into my model, but I sure didn't include everything. I never explored all possible cloud structures, only the most likely ones. I checked my software, but couldn't test every possible programming flaw. In most research, you keep close track of systematic errors-- how far is your answer from reality. In computer modeling, the numbers are usually perfectly correct, but a bad assumption or simple bug throws the answer out the window. Computer models don't convince--they aren't simple and they sure aren't physical. I can list my assumptions, show you my data, and describe my program. But I hope you'll still be skeptical-- there's plenty of places to goof up. Probably the only way to clinch the issue is a visit to the planet with a microscope and tweezers." I would guess his model was much simpler than a typical climate model. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 March 1996, 20:27:36 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do I posted in part: > As for whether things are improving, consider the following >quote from the paper "Climate Sensitivity" (by Robert E. Dickinson, >in Advances in Geophysics, volume 28 (1985), Issues in Atmospheric and >Oceanic Modeling Part A Climate Dynamics, p. 99-129, quote starts >p. 110) > > Thus in summary it appears that the largest sources of >uncertainty for the sensitivity of global average temperature to >external changes in tropospheric energy balance are the magnitude >of the ice-snow albedo feedback processes and the magnitude and >sign of cloud-radiation feedback processes. These conclusions >have been drawn for over a decade [cf. e.g., Schneider and >Dickerson (1974)]. > However, what is especially distressing is that recent GCM >studies have not contributed to narrowing our uncertainty as to those >processes but have suggested that we are rather more ignorant than >we previously thought. ... " Paul Farrar replied: >Wake up, Rip van Shearer! It's 1996, and we have extensive satellite >cloud climatologies. Plus measurements of long and short wave budgets, >sounder water vapor and temperature profiles to correlate with it. >Lots of data for busy bees to work on. The papers are all over the >literature which our sci.environment "greenhouse skeptics" don't, >and could not, read. Lots is even on the web -- try an AltaVista >search on "erbe and cloud" or something. Or "International >Satellite Cloud Climatology Project". > >The way physical scientists do things is: >a. Big cheeses make pronouncements on where we have shortcomings. >You caught one of these. >b. Lots of people think up instruments and experiments to fill in >the gaps. >c. Hopefully, some of those get done, and we learn something. >d. Iterate, but never to completion. Hopefully, to some sort of >convergence. I posted a 1985 reference saying no progress had been made (regarding certain issues) in 11 years. If you feel progress has been made in the following 11 years, I suggest you cite some references to that effect. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 March 1996, 20:28:26 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do Scott Nudds posted: > The key term in this thread - the one that you now conveniently ignore, >after having employed it - is the term "arbitrary". You referred to >"arbitrary assumptions". In an earlier post in this thread I explained what I meant by "arbitrary assumptions" as follows: > By arbitrary, I mean any assumption for which reasonable > alternatives exist given the present state of knowledge. To which Nudds replied: > Ok. Nudds appears to have forgotten this. Scott Nudds continued: > My statements accuse you of assuming that "arbitrary assumptions" are >used in GCM's. As usual, the burden of proof is on you to provide >examples of these "arbitrary assumptions". > > You appear incapable of doing so. So rail on child. Regarding "burden of proof" Nudds appears to feel that the burden of proof is always on anybody who disagrees with him. In this case he doesn't even have the guts to actually disagree with me by posting something like "Shearer is wrong, there are no arbitrary assumptions in GCMs". Instead he blathers on about how I have not proven 2+2=4 to his personal satisfaction. In any case I provided numerous examples of arbitrary assumptions in a post in a different thread. I will repeat one: > I recently obtained a "Description of the NCAR Commumity >Climate Model (CCM2)" from the net (gopher://isis.cgd.ucar.edu/99/ >processor/doc/TN-382.ps.). Some quotes > > p. 67: "... the number of layers is arbitrary. ... we >arbitrarily chose a constant layer thickness of 50 cm." James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 March 1996, 20:29:47 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Michael Tobis posted: >I never claimed "astonishing precision" for the models. I claimed >it for the physical constraints on the system they intend to >represent. Therefore I claim that the models are much more reliable >than biological or economic models of comparable complexity. ... This last sentence is complete nonsense. Biological and economic systems are subject (so far as we know) to the same physical constraints as climate. This says nothing about the reliability of empirical approximations on which the models depend. Why exactly should I have more faith in climate models than economic models? Do you believe climatologists are smarter than economists? Do you believe climatologists work harder than economists? Do you believe climatologists have higher professional standards than economists? Do you believe climatologists have purer hearts than economists? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 5 March 1996, 20:31:30 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Rich Puchalsky posted: >In any case, I don't see the conflict between what Tobis wrote and >Shearer's list. Tobis stated that the model implementation didn't >perfectly represent physical law in practise (almost a tautology). >The point is that a much larger percentage of the model's code represents >physical law, than, say, in an economics model. Finding a long list of >empirical approximations is not surprising; everyone knows they exist (look >back at the thread on flux corrections, for instance). Is this just >another argument of the form "Since we don't know everything; we know >nothing" or does Shearer have a suggestion for how better to improve our >models than to work on our existing ones? My objection to Tobis's post was that he appeared to me to attempting to obscure (and not for the first time) the difference between physical theories such as quantum mechanics which are in fact very well validated and climatological theories which generally are not very well validated. As for the percentage of code which is based on fundamental physical law, I see no reason to prefer a 100000 line climatology code which is 50% empirical to say a 50000 line economics code which is 100% empirical. If key parts of the model are inaccurate this limits the accuracy of the entire model regardless of how accurate the remainder of the model is. My argument is basically of the form "A chain is only as strong as its weakest link". Improving some parts of a computer model will do little or nothing to improve the reliability of the model as a whole if the improved parts were not the weak links. Rich Puchalsky continued: >Of course, Shearer may answer that complex modelling of this type is almost >worthless and shouldn't be worked on at all. In which case I really do >want to know whether Shearer is a modelling expert since I would like to >know what kinds of models he thinks are worthwhile. I think models which can be checked can be worthwhile. For example people have developed complicated models to predict performance of cars on government crash tests. Automakers find these models are useful. Nevertheless (as far as I know) the government still insists on actually crashing cars (rather than accept model results). Cars have been known to unexpectedly fail these actual tests. Under what conditions would Puchalsky be willing to replace actual crashes with model crashes for safety certification? (Note, I am not considering here the question of whether the government crash tests have much to do with real world safety.) Rich Puchalsky continued: >Note: Tobis didn't claim that the models provided "astonishing precision", >he said that immutable physical laws were known with astonishing precision. >Shearer is mis-quoting him above. Also, Tobis didn't say that he had >great confidence that such models "represent the real situation", he >said that the physical laws embedded in the model allowed for greater >confidence that the model represented the real situation than if the model >didn't embed those physical laws. The quotes are accurate. You might argue they are out of context, however since I gave the entire paragraph in which they appear at the top of my post, I don't think you have much of a case. As for embedding physical laws in models, I can embed ten zillion physical laws in a superbowl prediction model without improving the model reliability in the slightest. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:22:02 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Steve Emmerson posted: >You are correct. There are some parameterizations within models >that are empirical. This is because we either don't understand the >underlying physics or we do, but the computations are prohibitively >expensive. Being empirical, however, means that the parameterizations >have been vetted by comparing their predictions against nature. The >form of the parameterization and any "tuning" parameters have been >chosen or set to match, to the best of our ability, the behavior of the >relevant subsystem. Such parameterizations are far from "arbitrary" (in >the way that you use the word). Nor are they static. As new data >becomes available, the parameterizations are revetted. Additionally, >faster and more powerful computers allow better parameterizations to be >used. I defined my use of "arbitrary" in another post as follows: > By arbitrary, I mean any assumption for which reasonable >alternatives exist given the present state of knowledge. I would >expect that the large models contain hundreds of such assumptions. Do you deny that many of the parameterizations are arbitrary in this sense? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:23:05 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Michael Tobis posted: >I never claimed "astonishing precision" for the models. I claimed >it for the physical constraints on the system they intend to >represent. Therefore I claim that the models are much more reliable >than biological or economic models of comparable complexity. ... I replied: > This last sentence is complete nonsense. Biological and >economic systems are subject (so far as we know) to the same physical >constraints as climate. This says nothing about the reliability of >empirical approximations on which the models depend. Rich Puchalsky commented: >Wow, call Dr. McCarthy! I'm sure he'll be interested in this breakthrough >in AI. Just think about it -- economic systems behave in the way they >do because of the results of many human decisions. I didn't know that >someone had come up with simple physical laws that constrain these decisions... >I mean, of course resource constraints exist, but what physical law keeps >everyone in the U.S. from, to take a silly but not impossible example, >suddenly deciding to start reading Tolstoy half-time? As far as we know the human mind (and hence human) decisions are based on the same fundamental physical laws as the rest of the universe and could in principle be simulated. Of this is impossible in practice, but it is also impossible to model climate by following every atom in the atmosphere. As for silly examples I doubt any physical law bars everyone in the US from deciding to read Tolstoy half-time. This would however be very unlikely. Similarly no physical law (that we know of) excludes the possibility that every radioactive atom in the earth will decide to decay at the same time. I continued my earlier reply: > Why exactly should I have more faith in climate models than > economic models? > Do you believe climatologists are smarter than economists? > Do you believe climatologists work harder than economists? > Do you believe climatologists have higher professional > standards than economists? > Do you believe climatologists have purer hearts than > economists? Rich Puchalsky commented: >I'm tempted to say "yes to all four" of these last just for the satire >factor, but I won't. Instead I'll point out that climatologist's models >are much better at predicting the future than economists'. John McCarthy commented: >None of the above are necessary for climatological models to be better >than biological or economic models. It would suffice that the more of >the phenomena of climate are governed by known simulatable laws than >is the case for the phenomena of biology or economics. Michael Tobis replied in part: >I have no opinion on these matters. I am willing to claim that >climatologists are smart, work hard, have high professional >standards, and generally have pure hearts. I am also willing to claim >that their discipline is more scientifically mature than >economics, through no fault of the economists'. One of the >main intellectual attractions of climate research is that it >lies just at the limits of maximum complexity of systems that >can be studied rigorously, using the methods of mathematical >physics. Let me modify my first question above as the original is not exactly right. It has been suggested numerous times in this group that since I am not a climatologist, I should defer to the opinions of professional climatologists regarding climatology. However many of the same people making this suggestion have no shown willingness to defer to the opinions of professional economists regarding economics. Indeed several have been contemptuous of the entire profession. So why should I trust the opinions of climatologists more than the opinions of economists (regarding for example the usefulness of constructing complicated climate or economics models)? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:24:20 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Rich Puchalsky posted: >If a model consists of strict implementation of physical law, which determines >90% of the value of the model output, and an empirical section that determines >the other 10%, then the model is 90% accurate (assuming the physical part is >right) no matter how bad the empirical part is. This is naive. In general you cannot partition the error in this way. If you don't know anything about the empirical part how can you say it accounts for 10% of the value of the model output? In any case if we call the sensitivity to CO2 doubling the model output, this output will strongly depend on the empirical parts of current GCMs. I posted: > My argument is basically of the form "A chain is only as > strong as its weakest link". Improving some parts of a computer model > will do little or nothing to improve the reliability of the model as > a whole if the improved parts were not the weak links. Rich Puchalsky commented: >You have not shown that the empirical parts of GCM's are their weakest links. Well if we are stipulating that the non-empirical parts are based on fundamental physical laws known to astonishing precision and hence perfect, what's left? (Of course based on fundamental physical laws is a little vague. In many cases solving the equations the fundamental physical laws generate is impractical, so approximations are used. These approximations may be mathematically unsound in general and their use in GCMs may have no more justification than that they seem to work ok. This renders the distinction between empirical and non-empirical parts of the model a little fuzzy. In some sense the Navier-Stokes equations and the laws of thermodynamics are themselves empirical rather than fundamental.) I posted: > I think models which can be checked can be worthwhile. For Rich Puchalsky replied: >But GCMs are checked all the time. They are checked versus current >observational data. Through hindcasting, they are checked against >historical data that were not fed into the model. And as new data continue >to come in, they are checked against that. I don't understand the point >of your sentence above at all. To be precise I should have said adequately checked instead of checked. Suppose now the model output is average surface temperature. This depends on all sorts of inputs to the model: amount of CO2 in the atmosphere, location of the continents, length of the day, amount of axial tilt etc. I do not trust such a model to predict average temperature given some set of values for these input parameters if it has not been verified to give satisfactory results for a reasonable set of points in parameter space. In this case we can only check one point (namely the current conditions) for which in many cases the models have been forced to give the right answer. This does not constitute adequate checking in my opinion. My post quoted above continued: > example people have developed complicated models to predict performance > of cars on government crash tests. Automakers find these models are > useful. Nevertheless (as far as I know) the government still insists > on actually crashing cars (rather than accept model results). Cars > have been known to unexpectedly fail these actual tests. Under what > conditions would Puchalsky be willing to replace actual crashes with > model crashes for safety certification? (Note, I am not considering Rich Puchalsky commented: >The real world will continue to "crash" whether we model it or not. We >have no choice but to carry out this experiment. Therefore, there can be >no question of the models replacing actual experience. The purpose of >the models is to give us whatever information we can get to influence >the real-world crash before it happens. You are not reading carefully. I specifically said the purpose of the models was to predict performance on government crash tests (not performance in real world crashes). There is no natural law which requires the government to perform actual crash tests (which involve the collision of a car containing instrumented dummy humans with a barrier) rather than computer simulated crash tests before certifying cars. I posted: > As for embedding physical laws in models, I can embed ten > zillion physical laws in a superbowl prediction model without > improving the model reliability in the slightest. Rich Puchalsky commented: >But in a previous post you claimed that economic models were constrained >by physical laws, just like climatological ones. Care to explain this >sudden reversal? I claimed the real economy was constrained by physical laws just like the real climate. I made no such claim about the models. In any case I am skeptical of complicated economic models as well as complicated climate models so I don't know what "sudden reversal" is referring to. To give another example, a program to compute horoscopes may have many fundamental physical laws embedded in it. This does not increase my confidence in the program. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:25:16 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Civility I posted: > I have posted several examples which show that your statement > that "no feedback mechanism can exist that will produce cooling" is > false. Scott Nudds replied: > I'm sorry, the examples you have parroted, are strictly abstract >mathematics without application to the problem at hand. You have >provided only a fraction of the justification necessary to prove your >supposition that warming can cause cooling. Your burden is to show that >this is the case for the earth's climate. Some people do have trouble with abstract mathematics. However I have also posted examples of physical systems in which feedback causes a variable to respond opposite to the direction of forcing. Do you accept that such physical systems exist? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:27:24 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted: > First bugs do not occur random and cannot be expected to > produce random errors. Scott Nudds replied: > As a programmer, who just tracked down an applicaiton problem in which >an animation delay factor was cleared when a sound was played from a >particular code module, I can testify to the fact that computing errors >are essentially random. You apparently don't know a lot about your own field. Studies have shown that bugs in programs produced by independent groups are not independent. For example if A and B each independently produce programs (for the same problem) which fail one test case out of a set of 1000 randomly generated test cases, the odds that the failing case is the same are substantially more than 1/1000. This limits the usefulness of schemes to reduce the expected error rate of safety critical software (flight control, reactor control etc.) by independently writing three versions with some sort of majority vote control law. As another example, in a recent notorious case Intel produced Specint92 numbers which were 15% too high due to a bug in the implementation of a new compiler algorithm. Do you wish to claim that they were just as likely to have produced Specint92 numbers which were 15% too low? James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 6 March 1996, 20:28:31 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: climate models I posted: > Second the models do not in my opinion produce essentially > the same result. What is the result you claim all the models > produce? Scott Nudds replied: > All models show warming. Variance is on the order of 2'C. Your >"opinion" is clearly driven by personal faith rather than scientific fact. Warming is shown by simple models. What result, not predicted by simple models, do all the complicated climate models produce? Remember I have not and do not claim that the simple models are useless, only that the complicated models don't add much (if any) value. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 March 1996, 22:52:17 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds Len Evens posted: > By the way, there was a study reported on years ago >in the Scientific American, which claimed that on the basis of >sophisticated intelligence testing, mathematicians and theoretical >physicists were at the top of the intellectual ladder. Years >of experience, however, have taught me otherwise. Sounds plausible to me. What convinced you otherwise? I think it is the case that more physicists have made contributions in other fields than vice versa which would suggest physics requires something that other fields don't. It has always seemed to me that fields like biology tend to attract people who can't cope with calculus. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 March 1996, 22:53:38 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Global cooling or warming???-to Nudds I posted (in part) > Indeed several have been contemptuous of the entire profession. So > why should I trust the opinions of climatologists more than the > opinions of economists (regarding for example the usefulness of > constructing complicated climate or economics models)? Michael Tobis responded: >In this case, I imagine an objective answer could be obtained, by using >an information theory point of view, and objectively evaluating the >skill of the models of the disciplines in their proposed domains. >However, I'm apparently not the unbiased party to attempt such a >comparison, even if it could be funded. Things are not this simple. If economist's models are lousy and economists know they are lousy while climatologist's models are mediocre and climatologists think they are good, then the opinions of economists regarding models will be more trustworthy. In reality, of course, both disciplines have many models, some widely accepted, others controversial. I myself see no reason to think a lot less of the economics profession as a whole than of the climatology profession as a whole. If you are comfortable suggesting that those economists who have devoted their professional careers to working on large models of the economy have been wasting their time, you should be willing to contemplate, without excessive outrage, the possibility that some of the time spent constructing large climate models has been wasted as well. Michael Tobis continued: >On the other hand, I believe you are probably old enough to have >noticed the improvement in weather forecasting such that five day >forecasts are now routinely reliable, which was not the case quite >recently. Perhaps you can manage to yield the points that weather >forecasts are demonstrably improving and increasingly based on >computer models. Doesn't this constitute substantial "value added"? Actually I haven't, but I see no reason to doubt it. I have no objection to using complicated computer models for weather forecasting because the models are checked against reality every day. As I have stated repeatedly my objection is to models that can't be easily checked. Michael Tobis continued: >Have there been substantial recent improvements in economic theory? This is not relevant, I don't know of any substantial recent improvements in quantum mechanics, this doesn't make quantum mechanics less trustworthy. James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 March 1996, 22:54:47 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do The "arbitrary assumptions" argument continues. Scott Nudds posted: > Clearly, the burden of proof is with those who accuse. You have >accused modelers of using "arbitrary" assumptions. Key word "arbitrary". So Nudds feels my statement that GCMs contain arbitrary assumptions is an accusation. Apparently he feels that if GCMs do contain arbitrary assumptions this would be a serious defect. With friends like Nudds do climate modelers need enemies? I suppose it is useless to ask Nudds to apply his statement about the burden of proof to his own posts. Scott Nudds continued: > Either provide evidence that "arbitrary" assumptions have been used in >Global Climate Models, or admit that you have made this accusation based >on your own personal assumptions. and also: > I'm sure everyone else here understands my objection with your >accusation. It is the word "arbitrary". The term conveys a distinct >meaning, and by using it you have chosen to apply it to Global Climate >Models. I have defined what I meant by arbitrary in several previous posts. Thus: > By arbitrary, I mean any assumption for which reasonable > alternatives exist given the present state of knowledge. This is reasonably close to a dictionary definition (Webster's Ninth New Collegiate Dictionary, 1983, p.99 meaning 3a): "3a: Based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something < ~ division of historical studies into watertight compartments - A.M. Toynbee> " Scott Nudds continued: > In fact it is you who is guilty of objections based on personal >satisfaction. You chose to label the assumptions that are used in GCM's >as "arbitrary" because the results fo the models don't correspond with >your religious beliefs. > > Either provide evidence that "arbitrary" assumptions have been used in >GCM's or admit that your accusation is based on your own personal ignorance. I call the assumptions arbitrary because that is what they are. I provided evidence that arbitrary assumptions are used in GCMs in the very post you are replying to. Thus: > In any case I provided numerous examples of arbitrary >assumptions in a post in a different thread. I will repeat one: >> I recently obtained a "Description of the NCAR Commumity >>Climate Model (CCM2)" from the net (gopher://isis.cgd.ucar.edu/99/ >>processor/doc/TN-382.ps.). Some quotes >> >> p. 67: "... the number of layers is arbitrary. ... we >>arbitrarily chose a constant layer thickness of 50 cm." Here the description of a GCM refers to certain assumptions as arbitrary. Looks like evidence to me. However as a special bonus I will provide more evidence. Consider the following quote from the paper "Climate Sensitivity" (by Robert E. Dickinson, Advances in Geophysics, Volume 28 (1985), Issues in Atmospheric and Ocean Modeling, Part A, Climate Dynamics, edited by S. Manabe, p99-129, quote from p107): "How well can GCMs actually model global climate feedback terms related to the hydrological cycle? In considering this question, it is useful to compare results from different GCM groups and from different models developed by the same group. A danger in accepting GCM results as descriptions of reality is that some aspects, e.g. in the present context of global feedback terms, may depend on poorly modeled processes whose importance for the results obtained is not recognized. In GCM modeling as in all such complex scientific endeavors, there is a "follow-the-leader" tendency to use previously published parameterizations for physical processes without considering the dependence of modeling results on uncertainties in these parameterizations. On the other hand, arbitrary assumptions and parameterizations have at least some possibility of differing randomly between different models, especially those developed at different institutions. Thus, comparison of the results of different models can help uncover serious uncertainties that may not have been demonstrated through sensitivity studies with one particular model." James B. Shearer (email jbs@watson.ibm.com) ========================================================================= Date: 7 March 1996, 22:57:26 EST From: T41UC1 at PK705VMA To: usenet-poster at polecat.newsgate.ibm.com, JBS at YKTVMV Newsgroups: sci.environment X-Post-Me: Yes Subject: Re: Cooling; was: Re: CFCs in the atmosphere (was Re: Why do Michael Tobis posted: >I wonder whether Shearer's skepticism regarding such models extends to >models of the atmospheres of other planets, or the dynamics of stars, >or even to the pursuit of fluid dynamic modelling of industrial processes, >all of which are undertaken in an essentially similar way. In response I posted a quote from a book (Silicon Snake Oil) by Clifford Stoll in which he expressed skepticism about his own model of Jupiter's atmosphere. This was intended to be an answer to Tobis's query about "models of the atmospheres of other planets". For some reason Tobis took exception to this. Thus: >Does it occur to you that we might possibly have more information >about earth's atmosphere than Jupiter's? and also: >Quite so. A model of complexity comparable to GCMs of the Jovian >atmosphere would serve little purpose because of the lack of validation >data. The amount of validation data we have for the earth, on the >other hand, is so embarassingly vast that it is problematic. The >reason is that there is political momentum to fund earth observation >satellites but less to actually fund mere meteorologists to analyze >them! > >Again, you aren't making much sense. Models of Jupiter are necessarily >speculative. We just got our first in situ measurements in a >couple of months ago! We still only have one sounding of chemical >composition! You are the one who brought up "models of the atmospheres of other planets". Why blame me for it? You are the one who is not making much sense. Since I went to the trouble of getting a copy of Stoll's book, I can't resist giving another quote (Silicon Snake Oil by Clifford Stoll, 1995, p. 149-150): "Still, the finest computer model is still just a simulation of the physical world. You seldom know its assumptions or limitations, or even if it's programmed right. Computer models aren't gooshy. Plenty of computer models are just plain wrong or conflict with one another. Suppose the amount of carbon dioxide in the atmosphere doubles. What'll happen to the climate? The global- climate model developed by the Geophysical Fluid Dynamics Lab predicts Chicago summers could be seven degrees warmer and 30 percent drier. In comparison the Goddard Institute model expects only a three-degree warming and 5 percent wetter. Much of the difference depends on programmers' assumptions about the complexity of global-circulation patterns or the reflectance of the ground. But you won't know which programmer was right unless you wait a hundred years. Often, computer models can't be tested." Michael Tobis continued: >What is your connection with IBM anyway? Our group uses one of their >supercomputers in our climate modelling efforts. Do you really suggest >we drop the whole thing? That supercomputers have no use in science? >Curious. What am I being accused of here? An anti-conflict of interest? The fact that my position regarding complex c