# Physicists don't believe in global warming anymore? **URL:** \ **Category:** Great Debates\ **Created:** [July 19, 2008, 12:10am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005 "2008-07-19T00:10:51Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 25, 2008, 9:24pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/61 "2008-07-25T21:24:50Z")
[QUOTE=tomndebb] I note, however, that the confusion between the various numbers has already been explained in the poll citation. When the question is asked of “scientists,” (including physicists, biologists, chemists, astronomers, and any number of other folks, then the results come out as one in four have not yet been persuaded of AGW. However, when a similar question is asked of “climate scientists,” then the number of persuaded individuals jump to over 80%, with some portion of the less than 20% who are not fully persuaded including those who lean toward that explanation but may be holding out for a bit more data points. Given a base line poll from a (presumably) neutral pollster, then the APS would seem to have already met the conditions that would allow them to avoid publishing “personal” beliefs in the name of their membership. [/QUOTE] tomndebb, I’m not clear what you mean by this. Obviously, the editor of the APS journal doesn’t think that there is unanimity among the APS membership’s opinion on climate change, that’s his stated reason for bringing the debate to the fore by publishing. Given that acknowledged lack of unanimity within APS, how would a poll of some other group meet “the conditions that would allow [the APS leadership] to avoid publishing “personal” beliefs in the name of their membership.” All the best, w. PS - I didn’t understand your distinction above between “climate scientsts” and “scientists”, as the citation seems to use the two terms interchangeably. And the citation says: > [@](#): > > Eighty-four percent say they personally believe human-induced warming is occurring, and 74% agree that “currently available scientific evidence” substantiates its occurrence. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 25, 2008, 9:47pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/62 "2008-07-25T21:47:05Z")
**intention** : Just to go you a few examples - Table 9.1 looks at estimates of aerosol forcings obtained by data from Upper air, surface and deep ocean space-time temperature data, global mean and hemispheric difference insurface air temperature data, and global mean ocean heat uptake data. Fig 9.3 looks at satellite data measuring the shortwave flux radiation anomalies for the Mt. Pinatubo eruption. Section 9.4.1.2 looks at global temperatures during the 20th century as well as the geographic pattern of such changes (e.g., Fig. 9.6). Figures 9.7 and 9.8 look at the variability as a function of timescale of global mean temperatures and of continental scale temperatures. Fig. 9.14 shows re-analysis data of tropopause height. Section 9.5.1.1 looks at data for ocean heat content changes for the various ocean basins. Section 9.5.2 looks at data for sea level changes. Figure 9.17 looks at column-integrated water vapor data. Fig. 9.19 looks at data for rainfall in the Sahel. Section 9.6 discusses the use of observational constraints to determine climate sensitivity, including 20th century data of various sorts (such as global temperature, hemispheric difference in surface air temperature, and global ocean heat uptake), major volcanic eruptions, Northern Hemisphere temperatures from 1270-1850 from temperature reconstructions, and data from the last glacial maximum (LGM), i.e., the last ice age. Anyways, I am bored of listing all of this so you can go find other stuff yourself. The point is that there is plenty of data out there that is used. As in all sciences, the observational data is used to build, test, and constrain models and, as in all sciences over the last half century, computers are used to do much of the modeling. Computer models are also used in interpretation of data, e.g., to convert between observational data and the equilibrium climate sensitivities implied by that data (since much of the data is over short enough time intervals that one is not very close to “equilibrium”…although the LGM data is an exception). If you don’t want to deal with there being computer models in science, I suggest that the easiest thing for you to do is to time-travel back at least 50 years. The endless harping about computer models by the so-called “skeptics” like yourself is really getting rather boring and silly if you ask me. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 26, 2008, 1:36am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/63 "2008-07-26T01:36:33Z")
By the way, [this](http://www.newscientist.com/blog/environment/2008/07/now-will-you-publish-my-paper-showing.html) interview with one of the two editors of the newsletter, Al Saperstein, is interesting. Among the highlights: > [@](#): > > He stressed that that the article was not sent to anyone for peer-reviewing. Saperstein himself edited it. “I’m a little ticked off that some people have claimed that this was peer-reviewed,” he said. “It was not.” > [@](#): > > In April, the newsletter ran an article by retired nuclear physicist Gerald Marsh. Marsh argued that solar variations play a major role in the Earth’s climate, one which overrides human emissions of greenhouse gases. According to Marsh, future changes in the solar cycle could bring on the next ice age. > > … > > The editors put out a request for articles arguing “both sides of the debate.” They also asked Gerald Marsh to recommend authors who might contribute a piece arguing against the IPCC. > > Marsh gave five names, and the editors contacted all five. Monckton was the only one to respond. > [@](#): > > “Maybe I am unduly naive, but it seems the issue is not as clear cut as whether the Earth is flat or not. We’ve been getting comments saying ‘Now that you’ve published this will you publish my paper showing the Earth is flat?’ In my view, not being an expert, they are not in the same class,” says Saperstein. > > Yet, in hindsight, Saperstein admits that the newsletter might have been better off focusing on the impacts of climate change, not the causes. He also regrets the statement at the front of the newsletter which reads “There is a considerable presence within the scientific community of people who do not agree with the IPCC conclusion”. > > “It is clear that we made one error in my colleague’s introduction. In retrospect, the word ‘considerable’ should have been dropped.” ---
**Author:** ![sleestak](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@sleestak](https://boards.straightdope.com/u/sleestak)\ **Post date:** [July 26, 2008, 1:39am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/64 "2008-07-26T01:39:02Z")
[QUOTE=jshore] If you don’t want to deal with there being computer models in science, I suggest that the easiest thing for you to do is to time-travel back at least 50 years. The endless harping about computer models by the so-called “skeptics” like yourself is really getting rather boring and silly if you ask me. [/QUOTE] Well, the question regarding computer models is obvious: are the computer models accurate? The models apparently do not back test well which seems like it ought to be a giant flag that something isn’t right. The only information I can find on back testing the models show that they [suck](http://www.warwickhughes.com/hoyt/scorecard.htm) . Do you have other studies showing that the models, when back tested, give accurate numbers? If not, why should we trust the models when they do not back test well? Slee ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 26, 2008, 2:18am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/65 "2008-07-26T02:18:33Z")
[QUOTE=sleestak] The only information I can find on back testing the models show that they [suck](http://www.warwickhughes.com/hoyt/scorecard.htm) . Do you have other studies showing that the models, when back tested, give accurate numbers? If not, why should we trust the models when they do not back test well? Slee [/QUOTE] That is hardly a credible source, to say the least. It contains the usual lies, deceptions, and outdated information that we have already debunked countless times before. To some extent, the chapter that I referenced in the [IPCC report](http://www.ipcc.ch/ipccreports/ar4-wg1.htm) talks of back-testing…at least in the sense of comparing the observations with that predicted by the models with the forcings as they are understood. (There are certain uncertainties in this, of course, one being the uncertainty in aerosol forcing.) The more relevant chapter to read is the one before it, Chapter 8. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [July 26, 2008, 2:29am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/66 "2008-07-26T02:29:27Z")
[QUOTE=sleestak] Well, the question regarding computer models is obvious: are the computer models accurate? The models apparently do not back test well which seems like it ought to be a giant flag that something isn’t right. The only information I can find on back testing the models show that they [suck](http://www.warwickhughes.com/hoyt/scorecard.htm) . Do you have other studies showing that the models, when back tested, give accurate numbers? If not, why should we trust the models when they do not back test well? Slee [/QUOTE] I have to say it is your link that sucks, in the context of where we are with the OP, almost none of the cites are from serious scientific sites (many of the links are broken also) but are coming from skeptic blogs with points that are already debunked. As I have seen, the consensus among scientists, physicists and educators is that computer models are very good tools to use: > **[BBC NEWS | Special Reports | 629 | 629 | Climate scepticism: The top 10](http://news.bbc.co.uk/2/hi/in_depth/629/629/7074601.stm)** > > What are some of the reasons why "climate sceptics" dispute the evidence that human activities such as industrial emissions of greenhouse gases and deforestation are bringing potentially dangerous changes to the Earth's climate? > [@](#): > > Models are simply ways to quantify understanding of climate. They will never be perfect and they will never be able to forecast the future exactly. However, models are tested and validated against all sorts of data. Over the last 20 years they have become able to simulate more physical, chemical and biological processes, and work on smaller spatial scales. The 2007 IPCC report produced regional climate projections in detail that would have been impossible in its 2001 assessment. All of the robust results from modeling have both theoretical and observational support. Checking the history of computer modeling in relation to climate science it is clear to me that most of the criticism was somewhat valid 10 or more years ago, but climate models are using less of the “invalidating” tune ups that they were accused of using. And the worst thing for the skeptics is that most of that tune ups were found by the new models to had been good educated and evidence based “fudges” [http://www.aip.org/history/climate/co2.htm](http://www.aip.org/history/climate/co2.htm) > [@](#): > > By now there were a dozen teams around the world using computers to integrate every advance in observation or theory. As the 21st century arrived, the growing agreement among the rival teams, and the consistency of their models’ results with many different kinds of observations, became overwhelmingly convincing. Scarcely any reputable expert now doubted that CO2 and other greenhouse gases were at least partly responsible for the unprecedented warming all around the world since the 1980s. A final nail in the skeptics’ coffin came in 2005, when a team compared computer calculations with long-term measurements of temperatures in the world’s ocean basins (it was not in the air but the massive oceans, after all, that most of any heat added soon wound up). In each separate ocean basin, they showed a close match between observations of rising temperatures at particular depths, and calculations of where the greenhouse effect should appear. This was telling evidence that the computer models were on the right track. Nothing but greenhouse gases could produce the observed ocean warming — and other changes that were now showing up in many parts of the world, as predicted. > > The computations pinned down an imbalance. The Earth was now taking in from sunlight nearly a watt per square meter more than it was radiating back into space, averaged over the planet’s entire surface. That was enough energy to cause truly serious effects if it continued. James Hansen, leader of one of the studies, called it “smoking gun” proof of greenhouse effect warming.(56) > > Yet amid all the uncertainties about how carbon cycles operated, how much could we trust the computer models? Scientists are more likely to believe something if they can confirm it with an entirely independent line of evidence, preferably from somewhere nobody had looked before. Just such new evidence came up in the 1990s, thanks to an unexpected alliance of paleontology and plant physiology. Studies of plant species that had changed little since the rise of the dinosaurs (magnolia for one) showed that if you exposed them to a higher level of CO2, the structure of their leaves changed. Ancient fossil leaves showed just such changes. Several kinds of chemical studies confirmed that the level of the gas had swung widely over geological ages, and the temperature too. > > Eventually geochemists and their allies managed to get numbers for the “climate sensitivity” in ancient eras, that is, the response of temperature to a rise in the CO2 level. Over hundreds of millions of years, a doubled level of the gas had always gone along with a temperature rise of three degrees, give or take a couple of degrees. That agreed almost exactly with the numbers coming from many computer studies. [http://www.aip.org/history/climate/GCM.htm](http://www.aip.org/history/climate/GCM.htm) > [@](#): > > Another persistent problem was the poor quality of models that included the oceans. Modelers had long understood that reliable climate prediction would require coupling an atmospheric GCM to a full-scale ocean model. Such coupled models were beginning to dominate attention. They all tended to drift over time into unrealistic patterns. In particular, models seemed flatly unable to keep the thermohaline circulation going. The only solution was to tune the models to match real-world conditions by adjusting various parameters. The simplest method, used for instance by Suki Manabe in his influential global warming computations, was to fiddle with the flux of heat at the interface between ocean and atmosphere. As the model began to drift away from reality, it was telling him (as he explained), “Oh, Suki, I need this much heat here.” And he would put heat into the ocean or take it away as needed to keep the results stable. Modelers would likewise force transfers of water and so forth, formally violating the laws of physics to compensate for their models’ deficiencies.(95a) > The workers who used this technique argued that it was fair play for finding the effects of greenhouse gases, so long as they imposed the same numbers when they ran their model for different gas levels. Some other modelers roundly criticized flux adjustments as “fudge factors” that could bring whatever results the modelers sought. A few scientists who were skeptical about global warming brought the criticism into public view, arguing that GCMs were too faulty to prove that action must be taken on greenhouse gases. If a model was tuned to match the present climate, why believe it could tell us anything at all about a changed situation? The argument was too technical to attract much public attention. The modelers themselves, reluctant to give ammunition to critics of their enterprise, mostly carried on the debate privately with their colleagues. > > Around 1998, different groups published crudely consistent simulations of the ice age climate based on the full armament of coupled ocean-atmosphere models. This was plainly a landmark, showing that the models were not so elaborately adjusted that they could work only for a climate resembling the present one. The work called for a variety of ingenious methods, along with brute force — one group ran its model on a supercomputer for more than a year.(96\*) Later studies not only reproduced the ice age climate as well as it could be measured, but got an excellent match to another period when the weather patterns had been different from now, the warm “mid-Holocene” about 6000 years ago. > > Better still, by 1999 a couple of computer groups simulating the present climate managed to do away altogether with flux adjustments while running their models through centuries. Their results had reasonable seasonal cycles and so forth, not severely different from the results of the earlier flux-adjusted models. Evidently the tuning had not been a fatal cheat. Models without flux adjustments soon became standard.(97\*) > [@](#): > > But for a climate more or less like the present, the factors that modelers failed to understand seemed to have gotten incorporated somehow into the parameters. For the models did produce reasonable weather patterns for such different conditions as day and night, summer and winter, the effects of volcanic eruptions and so forth. At worst, the models were somehow all getting right results for wrong reasons—flaws which would only show up after greenhouse gases pushed the climate beyond any conditions that the models were designed to reproduce. If there were such deep-set flaws, that did not mean, as some critics implied, that there was no need to worry about global warming. As other experts pointed out, if the models were faulty, the future climate changes could be worse than they predicted, not better. > > Those who still denied there was a serious risk of climate change could not reasonably dismiss computer modeling in general. That would throw away much of the past few decades’ work in many fields of science and engineering, and even key business practices. The challenge, then, was to produce a simulation that did not show global warming. It should have been easy to try, for by the 1990s, millions of people owned personal computers more powerful than anything commanded by the climate modelers of the 1970s. But no matter how people fiddled with climate models, whether simple one- or two-dimensional models or full-scale GCMs, the answer was the same. If your model could reproduce something resembling the present climate, and then you added some greenhouse gases, the model always displayed a severe risk of future global warming.(105) > > The modelers had reached a point where they could confidently declare what was reasonably likely to happen. They did not claim they would ever be able to say what would certainly happen. Different model runs continued to offer a range of possible future temperatures, thanks mainly to the different ways they tried to figure how clouds worked. Worse, the various GCMs stubbornly continued to give a wide range of predictions for particular regions. Some things looked quite certain, like higher temperatures in the Arctic (hardly a prediction now, for such warming was becoming blatantly visible in the weather data). But for many of the Earth’s populated places, the models could not reliably tell the local governments whether to brace themselves for more droughts, more floods, or neither or both. > > By the dawn of the 21st century, climate models had become a crucial source of information for policy-makers and the public. Much of the modelers’ attention now focussed on working up results for the reports of the Intergovernmental Panel on Climate Change, rather than formal publication in obscure scientific journals. Struggling to provide a better picture of the changes that would come upon the planet as a whole and in each of its regions, the community of modelers grew larger and better organized. Projects to compare the models devised by different groups became a major ongoing activity. This cooperative framework forced the groups to agree on schemes for representing features of climate and formats for reporting their data, and once that was done, computer outputs could serve as raw material for groups that had nothing to do with the originators. That opened new paths for criticism and experimentation. A joint archive was established, which by 2007 contained more than 30 terabytes of data utilized by more than 1000 scientists.(105a) > > There were about a dozen major teams now, and the pictures of overall global warming that their ocean-atmosphere GCMs computed were converging. The decades of work by teams of specialists, backed up by immense improvements in computers and data, had gradually built up confidence. It was largely thanks to their work that, as the editor of Science magazine announced in 2001, a “consensus as strong as the one that has developed around this topic is rare in the history of science.”(106\*) Nearly every expert now agreed that the old predictions were solid — raising the CO2 level was all but certain to warm the globe. > > The computer numbers got an independent check. Other scientists were studying past climates clear back to the ice ages, lining up temperature changes with changes in greenhouse gases and other influences such as aerosols blown into the atmosphere from volcanoes. By 2006 they had arrived at fairly good numbers, which agreed well with what the computers calaculated. When experts were pinned down to be specific, they might say there was scarcely one chance in twenty that the doubling of CO2 (what was expected to come before the end of the century) would warm the planet less than 1.5°C. The upper limit was harder to fix, since doubled CO2 would push the atmosphere into a state not seen for tens of millions of years, but a rise greater than 6°C seemed equally unlikely. The most likely number for climate sensitivity was 3°C.(107) However, experience showed that scientists tended to be too optimistic about their level of certainty. Some insisted that there was a very real chance of an outcome better than the IPCC expected—or far worse. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 26, 2008, 2:29am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/67 "2008-07-26T02:29:50Z")
It is also worth noting and distinguishing the different ways that models are used. For example, the most famous way that they are used is simply to make a prediction of the climate sensitivity and of the future climate. However, that is not what Chapter 9 of the IPCC report is about. (It’s what Chapters 10 and 11 are about.) Chapter 9 is about using the models both to study what is responsible for the observed climate change…and also to study past climate changes in order to infer from it what range of climate sensitivities this change is compatible with. Note that in this latter case, the model isn’t predicting the climate sensitivity from first principles…It is merely serving as a conduit to infer what the climate sensitivity must have been to best reproduce the observed data. This approach is considerably less sensitive to deficiencies in the model than is the approach of just using the model to predict the climate sensitivity. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 26, 2008, 3:43am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/68 "2008-07-26T03:43:02Z")
**jshore** , thanks for the detailed references. I’ll take a look at them and get back to you. In the meantime, you say: [QUOTE=jshore] As in all sciences, the observational data is used to build, test, and constrain models and, as in all sciences over the last half century, computers are used to do much of the modeling. Computer models are also used in interpretation of data, e.g., to convert between observational data and the equilibrium climate sensitivities implied by that data (since much of the data is over short enough time intervals that one is not very close to “equilibrium”…although the LGM data is an exception). If you don’t want to deal with there being computer models in science, I suggest that the easiest thing for you to do is to time-travel back at least 50 years. The endless harping about computer models by the so-called “skeptics” like yourself is really getting rather boring and silly if you ask me. [/QUOTE] You have totally mis-stated my position regarding computer models. It is a recurring frustration in dealing with you, but we persevere. You are correct, all the sciences use models. Don’t you understand that I BOTH WRITE AND USE SCIENTIFIC COMPUTER MODELS MYSELF!!! How many times do I have to say that? But climate science is unique among the sciences in my experience, by virtue of claiming that the model results constitute evidence of anything. They don’t. They represent a fast-calculating but bug-ridden version of our best scientific guesses, understandings, simplifications, and insights. IF (and it’s a big IF) those scientific understandings, simplifications, insights, and guesses are correct (and the bugs don’t crash the spaceship into Mars), then the model results will be borne out in reality … but there’s more bad models than good models in the history of science, so we can have no a priori confidence that the model results are correct. This is particularly true given that we have no general theory of climate. We have a Theory of Relativity, and a Theory of Evolution, and a Newtonian Theory, but there is no Theory of Climate. This makes modeling much more difficult. To highlight the difference between evidence and model results, consider the GISS Model E GCM, the computer model used by Hansen and Schmidt over at NASA. As reported in [Present-Day Atmospheric Simulations Using GISS ModelE (Schmidt, Ruedy, Hansen, et al.),](http://pubs.giss.nasa.gov/abstracts/2006/Schmidt_etal_1.html) they ran a series of simulations of the historical climate. During those simulations, in their models the average global cloud cover was about 58% (p. 169). Does that finding constitute evidence about the average global cloud cover? Now, the cloud cover is a critical part of any climate model because clouds reflect sunlight back into space. In this way, clouds control the heat entering the earth’s climate system. And it is a very powerful control system. In round numbers, if the cloud cover varies by 10%, the amount of sunlight reflected changes by about 17 W/m2. To get this is the same 17 W/m2 change, CO2 would have to rise from the current value (~ 397 parts per million) to the astronomical value of 9,800 ppmv. A doubling of CO2 is the equivalent of a tiny, 2% change in global cloud cover. This means, of course, that until we can accurately model the clouds to within a couple of percent, any CO2 changes will be lost in the noise. So is the GISS model result of 58% cloud cover evidence of anything? Well, yes. It is evidence of the complexity of the climate system compared to our still early, crude efforts at modeling it. Because measurements in the real world show that the cloud cover is actually 69%, an 11% difference from the model. And lest you think that cloud cover is an isolated example, try this: > [@](#): > > 2.4 Principal Model Deficiencies > > Model shortcomings include: > > ~25% regional deficiency of summer stratus cloud cover off the west coast of the continents with resulting excessive absorption of > solar radiation by as much as 50 W/m2, > > deficiency in absorbed solar radiation and net radiation over other tropical regions by typically 20 W/m2, > > sea level pressure too high by 4-8 hPa in the winter in the Arctic and 2-4 hPa too low in all seasons in the tropics, > > ~20% deficiency of rainfall over the Amazon basin, > > ~25% deficiency in summer cloud cover in the western United States and central Asia with a corresponding ~5°C excessive summer warmth in these regions. [Climate Simulations 1880-2003, Hansen et al. including Schmidt](http://pubs.giss.nasa.gov/docs/notyet/inpress_Hansen_etal_1.pdf) So when that GISS Model E computer model says that humans are heating up the earth … sorry, jshore, that don’t impress me much. Because at the end of the day, all a computer model can do is calculate the results of the beliefs and understandings of the programmers. It doesn’t, and never can, “prove” or “establish” or be “evidence” that those particular beliefs and understandings are right. I’m sure you can see the circularity of that argument. A second, and totally independent, problem with computer modeling of complex systems is as follows: 1. How many computer runs have been done on lets say the GISS Model E and its predecessors? 2. Compared to the number published, how many of those were left on the cutting room floor, never saw the light of day? I’m sure you see the problem in terms of sample selection. A third, and totally independent, problem with computer modeling of complex systems is that the programs tend to be large, poorly documented, and the creation of a succession of programmers. As a man who has spent thousands of hours writing and debugging computer programs, I can assure you that this scenario guarantees bugs. A fourth, and totally independent, problem with computer modeling of the climate is the complexity of the task. Climate involves important processes on temporal scales from milli-seconds to millions of years, and on temporal scales from the molecular to planet-wide. It involves six major subsystems (atmosphere, ocean, biosphere, lithosphere, cryosphere, electro-magnetosphere). The sheer complexity is overwhelming. A fifth, and totally independent, problem with computer modeling is that the size and complexity climate forces the adoption of a whole host of parameters. Formally, each of these is a variable in the solution of the problem. As a result, it is easy to overdetermine the solution. There’s more, including technical stuff like the need to have unphysical atmospheric viscosity to prevent model runaway, but the conclusion is clear. Climate model results are not evidence of anything. They are interesting, they can be useful, they can give us insights, but they cannot provide evidence that humans are affecting the climate. All the best, w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 26, 2008, 4:49am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/69 "2008-07-26T04:49:56Z")
**jshore** , thanks for the detailed references. I’ll take a look at them and get back to you. In the meantime, you say: [QUOTE=jshore] As in all sciences, the observational data is used to build, test, and constrain models and, as in all sciences over the last half century, computers are used to do much of the modeling. Computer models are also used in interpretation of data, e.g., to convert between observational data and the equilibrium climate sensitivities implied by that data (since much of the data is over short enough time intervals that one is not very close to “equilibrium”…although the LGM data is an exception). If you don’t want to deal with there being computer models in science, I suggest that the easiest thing for you to do is to time-travel back at least 50 years. The endless harping about computer models by the so-called “skeptics” like yourself is really getting rather boring and silly if you ask me. [/QUOTE] You have totally mis-stated my position regarding computer models. It is a recurring frustration in dealing with you, but we persevere. You are correct, all the sciences use models. Don’t you understand that I BOTH WRITE AND USE SCIENTIFIC COMPUTER MODELS MYSELF!!! How many times do I have to say that? But climate science is unique among the sciences in my experience, by virtue of claiming that the model results constitute evidence of anything. They don’t. They represent a fast-calculating but bug-ridden version of our best scientific guesses, understandings, simplifications, and insights. IF (and it’s a big IF) those scientific understandings, simplifications, insights, and guesses are correct (and the bugs don’t crash the spaceship into Mars), then the model results will be borne out in reality … but there’s more bad models than good models in the history of science, so we can have no a priori confidence that the model results are correct. This is particularly true given that we have no general theory of climate. We have a Theory of Relativity, and a Theory of Evolution, and a Newtonian Theory, but there is no Theory of Climate. This makes modeling much more difficult. To highlight the difference between evidence and model results, consider the GISS Model E GCM, the computer model used by Hansen and Schmidt over at NASA. As reported in [Present-Day Atmospheric Simulations Using GISS ModelE (Schmidt, Ruedy, Hansen, et al.),](http://pubs.giss.nasa.gov/abstracts/2006/Schmidt_etal_1.html) they ran a series of simulations of the historical climate. During those simulations, in their models the average global cloud cover was about 58% (p. 169). Does that finding constitute evidence about the average global cloud cover? Now, the cloud cover is a critical part of any climate model because clouds reflect sunlight back into space. In this way, clouds control the heat entering the earth’s climate system. And it is a very powerful control system. In round numbers, if the cloud cover varies by 10%, the amount of sunlight reflected changes by about 17 W/m2. To get this is the same 17 W/m2 change, CO2 would have to rise from the current value (~ 397 parts per million) to the astronomical value of 9,800 ppmv. A doubling of CO2 is the equivalent of a tiny, 2% change in global cloud cover. This means, of course, that until we can accurately model the clouds to within a couple of percent, any CO2 changes will be lost in the noise. So is the GISS model result of 58% cloud cover evidence of anything? Well, yes. It is evidence of the complexity of the climate system compared to our still early, crude efforts at modeling it. Because measurements in the real world show that the cloud cover is actually 69%, an 11% difference from the model. And lest you think that cloud cover is an isolated example, try this: > [@](#): > > 2.4 Principal Model Deficiencies > > Model shortcomings include: > > ~25% regional deficiency of summer stratus cloud cover off the west coast of the continents with resulting excessive absorption of > solar radiation by as much as 50 W/m2, > > deficiency in absorbed solar radiation and net radiation over other tropical regions by typically 20 W/m2, > > sea level pressure too high by 4-8 hPa in the winter in the Arctic and 2-4 hPa too low in all seasons in the tropics, > > ~20% deficiency of rainfall over the Amazon basin, > > ~25% deficiency in summer cloud cover in the western United States and central Asia with a corresponding ~5°C excessive summer warmth in these regions. [Climate Simulations 1880-2003, Hansen et al. including Schmidt](http://pubs.giss.nasa.gov/docs/notyet/inpress_Hansen_etal_1.pdf) So when that GISS Model E computer model says that humans are heating up the earth … sorry, jshore, that don’t impress me much. Because at the end of the day, all a computer model can do is calculate the results of the beliefs and understandings of the programmers. It doesn’t, and never can, “prove” or “establish” or be “evidence” that those particular beliefs and understandings are right. I’m sure you can see the circularity of that argument. A second, and totally independent, problem with computer modeling of complex systems is as follows: 1. How many computer runs have been done on lets say the GISS Model E and its predecessors? 2. Compared to the number published, how many of those were left on the cutting room floor, never saw the light of day? I’m sure you see the problem in terms of sample selection. A third, and totally independent, problem with computer modeling of complex systems is that the programs tend to be large, poorly documented, and the creation of a succession of programmers. As a man who has spent thousands of hours writing and debugging computer programs, I can assure you that this scenario guarantees bugs. A fourth, and totally independent, problem with computer modeling of the climate is the complexity of the task. Climate involves important processes on temporal scales from milli-seconds to millions of years, and on temporal scales from the molecular to planet-wide. It involves six major subsystems (atmosphere, ocean, biosphere, lithosphere, cryosphere, electro-magnetosphere). The sheer complexity is overwhelming. A fifth, and totally independent, problem with computer modeling is that the size and complexity climate forces the adoption of a whole host of parameters. Formally, each of these is a variable in the solution of the problem. As a result, it is easy to overdetermine the solution. There’s more, including technical stuff like the need to have unphysical atmospheric viscosity to prevent model runaway, but the conclusion is clear. Climate model results are not evidence of anything. They are interesting, they can be useful, they can give us insights, but they cannot provide evidence that humans are affecting the climate. All the best, w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 26, 2008, 8:30am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/70 "2008-07-26T08:30:16Z")
GIGOBuster, thanks for your quote. You say: [QUOTE=GIGOBuster] Checking the history of computer modeling in relation to climate science it is clear to me that most of the criticism was somewhat valid 10 or more years ago, but climate models are using less of the “invalidating” tune ups that they were accused of using. [/QUOTE] Cite? [QUOTE=GIGOBuster] And the worst thing for the skeptics is that most of that tune ups were found by the new models to had been good educated and evidence based “fudges” [/QUOTE] Cite? 'Cause I haven’t seen any reduction in the tuning being done … w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 26, 2008, 8:56am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/71 "2008-07-26T08:56:34Z")
Ah, I see, GIGOBuster. Your author is conflating tuning with flux adjustment. No surprise. Yes, there is less flux adjustment in the models. No, there is not less tuning. Yes, the models are getting better. No, they don’t model clouds for sh_t … which means, of course, that they don’t model climate for sh_t. Yes, they are useful as research grade models for investigating a phenomenon. No, they are not industrial strength models that I’d trust to run a subway, much less as a basis for multi-billion dollar decisions. Yes, the grid size is way too large to include thunderstorms, which are the major means for moving tropical heat aloft. And no, their results are not evidence. w. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [July 26, 2008, 9:38am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/72 "2008-07-26T09:38:27Z")
[QUOTE=intention] GIGOBuster, thanks for your quote. You say: Cite? Cite? 'Cause I haven’t seen any reduction in the tuning being done … w. [/QUOTE] :rolleyes: Like if the quotes don’t say a thing. You are only repeating the same criticism that I see it was dismissed in academia before, if your criticism was valid the more progress in computer power and simulation would then show more critics at high levels denouncing the use of computer models, the reverse is happening. It is this lack of attention to quotes that made me conclude that you are not as serious as I thought a long time ago. Most of the embarrassing things you are saying here would not had been said if you had not dismissed what that physicist said in a quote I posted awhile back when he investigated if the criticism of the computer models was valid. On the whole the critics were and are wrong. (as I saw how you in that past discussion dismissed their investigations, it was not surprising to see that what historians are saying about the evolution of the computer research would also be dismissed or ignored by the critics. As computer models are not ignored in serious research, the criticisms posted here are not very convincing) The confidence in the modeling comes also by the fact that others can compare the results with non computer statistical analysis. > **[Stronger Evidence For Human Origin Of Global Warming](http://www.sciencedaily.com/releases/2007/07/070730141145.htm)** > > A recent statistical analysis strengthens evidence that human activities are causing world temperatures to rise. Most climate change scientists model Earth systems from the ground up, attempting to account for all climate driving forces.... > [@](#): > > Verdes’ analysis demonstrates that these natural causes do not completely explain the observed warming. > > Verdes calculated the amount of non-natural influence required to match the increases in temperature observed in the last 150 years. He plotted the influence over time. Then, he compared it to the evolution of greenhouse gasses, taking into account the cooling due to aerosols. With allowances for error, he found that influences attributable to greenhouse gasses mirror the graph of non-natural influence needed to explain the observed temperature increase of recent decades. > > His research shows that, if you look at global warming as a puzzle, and you put together the natural factors such as increased solar radiation and reduced volcanic activity, a hole remains. The human factors of greenhouse gas and aerosol emission complete the picture. And I see that you still insist on the whopper that there is no theory of what is driving the Climate Change, The theory is that CO2 and other gases are responsible for the warming, and that there is a human factor in the current warming. The AGW theory is precisely the point of the discussions and the target of the skeptics. [http://www.realclimate.org/index.php/archives/2007/12/les-chevaliers-de-l’ordre-de-la-terre-plate-part-ii-courtillots-geomagnetic-excursion/](http://www.realclimate.org/index.php/archives/2007/12/les-chevaliers-de-l%E2%80%99ordre-de-la-terre-plate-part-ii-courtillots-geomagnetic-excursion/) > [@](#): > > Still, the basic prediction of warming is founded on very fundamental physical principles relating to infrared absorption by greenhouse gases, theory of blackbody radiation, and atmospheric moist thermodynamics. All these individual elements have been verified to high accuracy in laboratory experiments and field observations. For a time, there was some remaining uncertainty about whether water vapor feedback would amplify warming in the way hypothesized in the early energy balance models, but a decade or two of additional observational and theoretical work has shown that there is no real reason to doubt the way in which general circulation models calculate the feedback. When modified by inclusion of the cooling effect of anthropogenic aerosols, the theory gives a satisfactory account of the pattern of 20th and 21st century temperature change. > > No other theory based on quantified physical principles has been able to do the same. If somebody comes along and has the bright idea that, say, global warming is caused by phlogiston raining down from the Moon, that does not make everything we know about thermodynamics, infrared absorption, energy balance, and temperature suddenly go away. Rather, it is the job of the phlogiston advocate to quantify the effects of phlogiston on energy balance, and incorporate them in a consistent way beside the existing climate forcings. Virtually all of the attempts to poke holes in the anthropogenic greenhouse theory lose sight of this simple and unassailable principle. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [July 26, 2008, 10:26am UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/73 "2008-07-26T10:26:33Z")
[QUOTE=intention] Yes, there is less flux adjustment in the models. No, there is not less tuning. [/quote] Your turn, Cite? [QUOTE=intention] Yes, the models are getting better. No, they don’t model clouds for sh_t … which means, of course, that they don’t model climate for sh_t. [/QUOTE] :rolleyes: Like if modelers ignore that. > **[Researchers Improve Predictions Of Cloud Formation For Better Global Climate...](http://www.sciencedaily.com/releases/2004/12/041214082116.htm)** > > Atmospheric scientists have developed simple, physics-based equations that address some of the limitations of current methods for representing cloud formation in global climate models – important because of increased aerosol pollution that gives... > **[RealClimate: An Aerosol Tour de Forcing](https://www.realclimate.org/index.php/archives/2006/02/an-aerosol-tour-de-forcing/)** > > RealClimate: Guest commentary from Ron Miller and Dorothy Koch (NASA GISS) Scientists have confidence in a result to the extent that it can be derived by different investigators. Their confidence is increased if different techniques lead to the same... > [@](#): > > Progress will come by more systematic comparisons among studies to identify key uncertainties. The unambiguous distinction between individual aerosol species within models will eventually become possible by direct observation as a result of more discerning instruments. Nonetheless, models will remain valuable for their ability to distinguish natural and anthropogenic sources of the same aerosol species. While Bellouin et al. assume that all soot particles over the ocean are anthropogenic, naturally occurring forest fires contribute as well. As consensus emerges regarding the global aerosol forcing, attention will turn to regional values that cause local changes to climate and heat redistribution by the atmosphere. Because of the added complexity of cloud physics, the aerosol indirect effect may be even more resistant to consensus. Aerosol forcing remains a crucial problem because its offset of greenhouse warming is expected to decrease with time as governments address the health problems associated with aerosols. Because of their comparatively short lifetimes, the concentration of aerosols decreases much faster than that of CO2 given a reduction in fossil fuel use. Regardless of the absolute amount of the forcing, future reductions in aerosol emissions will be a positive forcing, amplyfying the warming effects of increasing greenhouse gases. [QUOTE=intention] Yes, they are useful as research grade models for investigating a phenomenon. No, they are not industrial strength models that I’d trust to run a subway, much less as a basis for multi-billion dollar decisions. [/QUOTE] Awhile ago I pointed out that different groups in different nations are arriving to the same conclusions with their own modeling, I would have expected to see a couple of those high research groups denouncing the use of models if they are so unreliable as some claim. (I do see that there is a bit of unreliability, but this is being reduced thanks to data from NASA regarding clouds, however seeing evidence that models are more correct than wrong is the main reason why they are not dismissed in serious research) Problem is that some new research is showing that the warming could get worse with the new data: [http://www.cbc.ca/technology/story/2007/05/10/science-nasa-climate.html](http://www.cbc.ca/technology/story/2007/05/10/science-nasa-climate.html) [QUOTE=intention] Yes, the grid size is way too large to include thunderstorms, which are the major means for moving tropical heat aloft. And no, their results are not evidence. w. [/QUOTE] Alone, no; however they are, as mentioned before, checked with other evidence. And they confirm other evidence as they continue to rely more on the physical and chemical reactions and less on “discredited” tune-ups. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 26, 2008, 1:36pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/74 "2008-07-26T13:36:42Z")
**intention** , thanks for your response. [QUOTE=intention] But climate science is unique among the sciences in my experience, by virtue of claiming that the model results constitute evidence of anything. [/QUOTE] So, could you list the physical sciences that you have actively worked and published in that have led you to be able to make the conclusion about how models are used in climate science as compared to how they are used in these other sciences? I guess basically your whole litany of complaints comes down to the fact that your expert judgement about the models and their utility and the physical evidence and what it shows differs from the expert judgement of almost all of the scientists in the field, of the National Academy of Sciences and the analogous academies in the other G8+5 nations, of the AAAS, of the APS, the AMS, and AGU councils, etc., etc. So, the question that is important to answer is what reason we have to assume your expert judgement is better than theirs. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 26, 2008, 9:45pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/75 "2008-07-26T21:45:25Z")
[QUOTE=jshore] **intention** , thanks for your response. [QUOTE=intention] But climate science is unique among the sciences in my experience, by virtue of claiming that the model results constitute evidence of anything. [/QUOTE] So, could you list the physical sciences that you have actively worked and published in that have led you to be able to make the conclusion about how models are used in climate science as compared to how they are used in these other sciences? I guess basically your whole litany of complaints comes down to the fact that your expert judgement about the models and their utility and the physical evidence and what it shows differs from the expert judgement of almost all of the scientists in the field, of the National Academy of Sciences and the analogous academies in the other G8+5 nations, of the AAAS, of the APS, the AMS, and AGU councils, etc., etc. So, the question that is important to answer is what reason we have to assume your expert judgement is better than theirs. [/QUOTE] This is a wholly inaccurate description of my objections to the problems I see in climate science. I don’t have a “whole litany of complaints”, I have specific scientific objections that you don’t seem to want to deal with. Instead, you keep returning to different ways of saying “father knows best”, and “trust the scientists, dear, they’re your friends”. However, despite this mis-characterization of my views, I persevere. So, a couple of thoughts about this, **jshore** : 1. As we have determined, the APS statement does not even represent the judgement of its own members. It represents at best the majority view of its council of 14 leaders. Nor does the AAAS statement, nor the AMS, nor the rest. I thought you’d been following this discussion. 2. You seem to misunderstand how science works. I have made a falsifiable statement, that in my experience climate science seems to be unique among sciences in that it treats computer model results as evidence. If you don’t believe that (and obviously you don’t), go out and find evidence that it is not true. I cannot prove that it is true, no matter how many sciences I’ve investigated, because that is the nature of science. So asking me which sciences I have studied just shows that, despite the fact that you are a scientist, you have not yet grasped the nettle of “falsifiability”. 3. I still don’t understand why you think consensus means anything regarding scientific truth. In my father’s lifetime, the scientific consensus on eugenics was so strong that hundreds of people were sterilized in the name of science. Did that firm, unshakeable scientific consensus make eugenics true? No, but it allowed the believers in eugenics to make the same kind of simplistic claims you make, claims that have at their basis that famous scientific dictum, “it must be scientifically true because everyone else believes it”. I forget, was it Einstein that discovered that famous principle, or Isaac Newton? And as I pointed out before, a large number of scientists believe that there is an invisible, immortal being who loves them dearly and yet is quite willing to see them put into eternal torment. This consensus, however, does nothing to establish the existence of that being, any more than your (claimed) consensus on climate models means that the models are valid. This stupid allegiance to “consensus” even arises in the models themselves, where people think that if the models agree, it must mean that the models are right … and if you don’t see the problems with that belief, I’m afraid I can’t help you any further. w. ---
**Author:** ![Baldwin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/baldwin/32/7264_2.png) [@Baldwin](https://boards.straightdope.com/u/Baldwin)\ **Post date:** [July 26, 2008, 10:13pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/76 "2008-07-26T22:13:25Z")
[QUOTE=intention] 2. You seem to misunderstand how science works. I have made a falsifiable statement, that in my experience climate science seems to be unique among sciences in that it treats computer model results as evidence. If you don’t believe that (and obviously you don’t), go out and find evidence that it is not true. [/QUOTE] How can it be falsified unless you clarify the term “my experience”? You were asked exactly what that meant; you haven’t answered. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [July 26, 2008, 10:33pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/77 "2008-07-26T22:33:14Z")
[QUOTE=intention] This is a wholly inaccurate description of my objections to the problems I see in climate science. I don’t have a “whole litany of complaints”, I have specific scientific objections that you don’t seem to want to deal with. Instead, you keep returning to different ways of saying “father knows best”, and “trust the scientists, dear, they’re your friends”. [/quote] Well, the point is your complaints amount to a statement that modeling the climate is hard and that the models are only approximations of reality with many deficiencies. Well, thanks for telling us that but we already knew it. The question is whether they are useful enough to serve as tools in understanding what past climate change says about climate sensitivity, to allow us to detect the extent to which the current climate change is being caused by different factors, and to make some predictions (with fairly large error bars) about the future climate change given assumptions about future emissions and so forth. And frankly, such a question requires expert judgement. It requires the judgement of those who are actually best qualified to judge. And, while you are clearly an intelligent guy, I don’t believe that your judgement counts that strongly stacked up against the judgement of those in the field who think very differently from you. > [@](#): > > 1. As we have determined, the APS statement does not even represent the judgement of its own members. It represents at best the majority view of its council of 14 leaders. Nor does the AAAS statement, nor the AMS, nor the rest. I thought you’d been following this discussion. Well, we do have some pretty good poll numbers on the AGU and the AMS. But regardless, as I have pointed out, it is perhaps not unreasonable to come up with the hypothesis that there might be a few organizations whose councils might become somewhat out-of-touch with their membership (although I think it would be hard for even one such scientific organization to become severely out-of-touch without there being significant controversy within the organization). However, you are proposing a grand collusion whereby all these different organizations have done so, which basically is a conspiracy theory. To make an analogy, your argument seems to be, “Well, it is perfectly possible that we could roll on 6 on this one die. And, it is perfectly possible that we could roll a six on this other die. And, it is perfectly possible that we could roll a six on this third die… Therefore, it is perfectly reasonable to assume that we roll a six on all 100 dies that we have here.” That sort of logic doesn’t really fly. > [@](#): > > 1. You seem to misunderstand how science works. I have made a falsifiable statement, that in my experience climate science seems to be unique among sciences in that it treats computer model results as evidence. If you don’t believe that (and obviously you don’t), go out and find evidence that it is not true. I cannot prove that it is true, no matter how many sciences I’ve investigated, because that is the nature of science. All the sciences use models to help them understand things. That is how science is done. You make models based on what you know from experiments or observations, you check them against experiments or observations, you use them to make predictions. You constantly test and refine the models. Etc., Etc. This is how it is done in all sciences including climate science. No sciences are exactly the same but I don’t see any dramatic qualitative difference between climate science and other sciences. > [@](#): > > 1. I still don’t understand why you think consensus means anything regarding scientific truth. Well, how do we know what the current state of the science is without asking the scientists? They are the ones best qualified to know. The scientists give us their best estimates of what is known, what is not known, how strongly each conclusion is, and so forth. And, if you want to participate in that process, I encourage you to do so by continuing to study climate science, publish papers (although I recommend trying for credible journals widely available and respected rather than “Energy and Environment”), etc. What I don’t think is that useful is when you try to come before the general public and tell us that you think most of the scientists have it wrong. It is certainly your right to do so but I think you should ask yourself why we should believe you rather than the vast majority of scientists. And, while you are a smart guy, I have also discovered in our discussions that you have your own strong biases, are wrong on some pretty basic stuff, and that you state these very wrong statements without the slightest amount of doubt (which makes me very skeptical of your strongly-stated statements that I haven’t been able to verify). [If you think I am being unfair here in not giving specific examples, I’ll just say (1) Gavin Schmidt and ensemble averages vs individual model runs and (2) whether the amplification of temperature as you go up in the tropical atmosphere is a specific prediction for the mechanism of greenhouse gas forcing or a more general prediction for all sorts of forcings and temperature fluctuations.] > [@](#): > > And as I pointed out before, a large number of scientists believe that there is an invisible, immortal being who loves them dearly and yet is quite willing to see them put into eternal torment. This consensus, however, does nothing to establish the existence of that being, any more than your (claimed) consensus on climate models means that the models are valid. Well, people cling to religion for various reasons. However, most scientists separate whatever religious beliefs that they might have from their science. One example of someone who does not is Roy Spencer who is one of the best credentialed of the skeptics and, frankly, one of the very few who is arguing things right now that are not so trivially incorrect that even I can spot most of the weaknesses. Spencer has unambiguously endorsed intelligent design as being just as scientific as evolution. So, there you have one of the current darlings of the skeptics (see, for example, [here](http://wattsupwiththat.wordpress.com/2008/07/22/roy-spencers-testimony-before-congress-backs-up-moncktons-assertions-on-climate-sensitivity/))…and really one of the few respectable scientists left in that camp…and, while he seems to be a reasonably decent scientist, statements like he has made in regard to intelligent design lead me to question whether he has the best scientific judgement…particularly when scientific evidence conflicts with his deeply-held beliefs. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 28, 2008, 5:13pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/78 "2008-07-28T17:13:39Z")
[QUOTE=intention] I have made a falsifiable statement, that in my experience climate science seems to be unique among sciences in that it treats computer model results as evidence. [/QUOTE] Consider it falsified (leaving aside what your experience may be). Ever seen an [animation](http://web.uct.ac.za/depts/cigces/Condrift.htm) of continental drift, or a map of Pangaea or Gondwana? Geologists made those using computer models, with data inputs from geophysics, palaeontology, stratigraphy and many other disciplines. I know this because I’ve worked on one such model [at my old uni](http://web.uct.ac.za/depts/cigces/cigces.htm). ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 28, 2008, 7:51pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/79 "2008-07-28T19:51:14Z")
[QUOTE=MrDibble] Consider it falsified (leaving aside what your experience may be). Ever seen an [animation](http://web.uct.ac.za/depts/cigces/Condrift.htm) of continental drift, or a map of Pangaea or Gondwana? Geologists made those using computer models, with data inputs from geophysics, palaeontology, stratigraphy and many other disciplines. I know this because I’ve worked on one such model [at my old uni](http://web.uct.ac.za/depts/cigces/cigces.htm). [/QUOTE] **MrDibble** , thanks for the contribution. Unfortunately, you did not understand the challenge. Certainly, computer models are used in geology, as in all sciences. But the models are not claimed to be evidence for continental drift. Evidence consists of things like showing that the rocks of say two continents that used to be one continent are the same. If the models claimed some kind of drift and the rocks were not the same, the geologists would go back to the drawing board and re-work the model. In climate science, on the other hand, when the models and the evidence diverge, we are told that the evidence must be wrong … that’s the oddity of climate science that I don’t see in any other science. w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [July 28, 2008, 7:52pm UTC](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005/80 "2008-07-28T19:52:46Z")
**jshore** , I’ve finally gotten a chance to review what you call “evidence”. [QUOTE=jshore] **intention** : Just to go you a few examples - Table 9.1 looks at estimates of aerosol forcings obtained by data from Upper air, surface and deep ocean space-time temperature data, global mean and hemispheric difference insurface air temperature data, and global mean ocean heat uptake data. Fig 9.3 looks at satellite data measuring the shortwave flux radiation anomalies for the Mt. Pinatubo eruption. Section 9.4.1.2 looks at global temperatures during the 20th century as well as the geographic pattern of such changes (e.g., Fig. 9.6). Figures 9.7 and 9.8 look at the variability as a function of timescale of global mean temperatures and of continental scale temperatures. Fig. 9.14 shows re-analysis data of tropopause height. Section 9.5.1.1 looks at data for ocean heat content changes for the various ocean basins. Section 9.5.2 looks at data for sea level changes. Figure 9.17 looks at column-integrated water vapor data. Fig. 9.19 looks at data for rainfall in the Sahel. Section 9.6 discusses the use of observational constraints to determine climate sensitivity, including 20th century data of various sorts (such as global temperature, hemispheric difference in surface air temperature, and global ocean heat uptake), major volcanic eruptions, Northern Hemisphere temperatures from 1270-1850 from temperature reconstructions, and data from the last glacial maximum (LGM), i.e., the last ice age. Anyways, I am bored of listing all of this so you can go find other stuff yourself. The point is that there is plenty of data out there that is used. As in all sciences, the observational data is used to build, test, and constrain models and, as in all sciences over the last half century, computers are used to do much of the modeling. Computer models are also used in interpretation of data, e.g., to convert between observational data and the equilibrium climate sensitivities implied by that data (since much of the data is over short enough time intervals that one is not very close to “equilibrium”…although the LGM data is an exception). If you don’t want to deal with there being computer models in science, I suggest that the easiest thing for you to do is to time-travel back at least 50 years. The endless harping about computer models by the so-called “skeptics” like yourself is really getting rather boring and silly if you ask me. [/QUOTE] I have already discussed the problems with computer climate models, and the reasons they are not evidence. I have asked for evidence. In response to my request for evidence (not model results) you list the following from your citation: Table 9.1 - This lists what computer climate models say about aerosols Figure 9.3 - Compares Pinatubo aerosol results with computer climate models. Section 9.4.1.2 - This is titled “Simulations of the 20th Century”, which might have given you a clue that it is not evidence, it’s Planet GISS. Figure 9.7 - This compares observations and computer climate models of power spectra of global mean temperatures (they don’t agree for shit, but that doesn’t stop them). Figure 9.8 - The same as 9.7 but for continental mean temperatures. Figure 9.14 - This compares computer climate models and “reanalysis data” (data which has been generated to agree with a computer climate model forced with real data.) So this one is not even comparing models to data, it’s comparing models to our best guess about the data based on … models. Section 9.5.1.1 - This compares ocean temperatures with … you guessed it, computer climate models. Section 9.5.2 - This compares sea level with … you guessed it. Figure 9.17 - This compares water vapor with … the usual suspects. Figure 9.19 - This compares Sahel rainfall, not with individual climate models, but with an ensemble of computer climate models. Section 9.6 - They say the results in Section 9.6 are from _“varying parameters in climate models that influence the ECS in those models, and then attaching probabilities to the different ECS values based on the realism of the corresponding climate change simulations.”_ Can you say “models”? I knew you could … * * * Now, let me review how we got here. I had said: [QUOTE=intention] elucidator, thank you for statement of belief. Unfortunately, every time I ask what this mysterious “evidence” might be, people show me computer model results. Sorry, that’s not evidence, as anyone who has ever made a computer model knows. All computers can reflect are the assumptions, beliefs, and parameters of the programmers. So, elucidator, I continue my quest to find the mysterious “evidence” that shows that increasing CO2 is responsible for global warming. Perhaps you could point it out for me. [/QUOTE] To this request for evidence and not computer model reports, you replied: [QUOTE=jshore] You can start with Chapter 9 of the IPCC report. [/QUOTE] When I said that citing a whole chapter was meaningless, you sent me the exact references above. Now my question is … did you: 1. Notice that I had asked for evidence and NOT for computer model results, and decide to send me citations to computer model results anyway?, or 2. Not notice that I had asked for evidence and NOT for computer model results? or 3. Hope that I wouldn’t notice that you had sent computer model results when I had specifically asked for evidence and NOT computer model results? 4. Realize that Chapter 9 didn’t contain any evidence, so you sent me computer model results instead, or 5. ??? Because one thing’s for sure, you didn’t send what I had specifically asked for, and what you said you would provide. I’m still waiting for your elusive evidence. w. [Previous page](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005.md?page=3) [Next page](https://boards.straightdope.com/t/physicists-dont-believe-in-global-warming-anymore/457005.md?page=5)