Dak Posted December 21, 2007 Posted December 21, 2007 I have not tried to argue that the data was linear, which is an accusation thrown at me rather often - I presume out of desperation, due to having no better argument. I merely said that, if we drew a straight line through the warming figures for the past 30 years, it would approximate a fit quite well. This is true, and does not consitute a claim that all is linear. your repeated claims that the current warming = the average warming over the last 30 years requires a linear fit in order to be true, as has been pointed out to you. as the trend is non-linear and accelerating, the warming at the beginning of that range would have been < the average < warming at the end of that range (i.e., now). this is actually evident in the data that pangloss eventually provided for you. My comments about the psychology of group extremism are quite correct, and accurate in terms of what we know of human psychology. The principle applies to scientists as well as anyone else. This is a good reason why data is king. very well, do you have any data/refferences that would suggest that this is the case? the reason i'm skeptical of your suggestion is that humans are prone to a number of biases (conformational bias, for one example) which scientists are generally trained to be aware of and relatively resistant to (blind assays, for example, seem to work quite well at negating conformational bias), and the peer-review system seems quite apt at weeding out any biases that get through. i'm finding it a bit difficult to accept that, in this area, science completely screws up and falls prone to an apparently documented and well-known psycological phenomena, and that no-one has jumped for the fame and glory of demonstrating that this is/may be the case by publishing a paper on it, whilst there are numerous papers on, e.g., conformational bias.
swansont Posted December 21, 2007 Posted December 21, 2007 Dak said : "so yeah, it's not that i'm trying to 'daemonize' SL (or anyone else) for not having a 'politically corect oppinion' , it's just that i wish he'd stop cherry-picking and ignoring the obvious flaws in his arguments once they're pointed out." It amazes me that we still have so much fuss about so little. All this began when iNow, quite wrongly, queried the average warming figures for the past 30 years. I gave two perfectly good references which iNow chose to reject. No one else, except Pangloss, had the integrity to stand up and say : "Hey iNow, stop arguing. Those figures are right." I have not tried to argue that the data was linear, which is an accusation thrown at me rather often - I presume out of desperation, due to having no better argument. I merely said that, if we drew a straight line through the warming figures for the past 30 years, it would approximate a fit quite well. This is true, and does not consitute a claim that all is linear. On the other hand, to look at the very minor changes in warming rate over 30 years, and claim that is statistically meaningful evidence of exponential growth, is a load of crock. You have once again mischaracterized the chain of events, but this has been pointed out may times; you can go back and reread previous posts to see the details. You made a linear projection of temperature, which was the objection. One thing you haven't acknowledged is the measurement of CO2 concentrations, which — as you recognize — are a significant driver of the temperature change. It is quite obviously an exponential. Your (well, everybody's) admission that CO2 levels several decades before did not have a significant effect on temperature is another bit of data that shows that the longer-term trend cannot be treated as linear. Despite the fact that a linear fit to the graph in question yields the numbers you gave, the projection of further tempeature increase and the conclusion you drew (i.e. whether a 3ºC increase is likely) isn't justified. My only point here has been that skepticism is part of science, not its enemy, and when you guys demonize people like myself and SkepticLance, the religious right just laughs and sits back and relaxes, watching us do their work for them. I just think we can do better than that, that's all. You guys should EMBRACE SkepticLance, not bemoan the fact that his opinion "reeks". Shout his existence on our board from the highest mountaintop. Look at the skeptic we have in our midst, and how we listen to what he has to say! Look at how we answer him point by point, and acknowledge him when he's right, but make it clear when he's wrong! We know he's not Rush Limbaugh, he's something far more useful and important: An INTELLIGENT skeptic on global warming. That's an INCREDIBLY important thing. And look -- Global Warming STILL HOLDS UP! Holy cow! That's just it, though. We have pointed out where arguments were wrong, and the posts have been ignored. Count up the number of times that Lance has stated that iNow "denied his data," (and all of the related claims) and the number of times that people have rebutted that. The really ironic thing here is that SkepticLance is not denying that the recent temperature changes are induced by human-generated CO2, and yet, there are claims that challenging his claims is politics and/or political correctness. If that were actually the case, there would be no argument — why criticize someone who agrees with you? The reality is that SkepticLance is being challenged because there are flaws in the analyses he's presented, which have been pointed out multiple times, to no avail. And conclusions drawn from invalid arguments are invalid (even if they end up with the right answer). There's nothing wrong with being skeptical. But a skeptic still has to follow the rules of science. A skeptic has to have a point where the quality and quantity of data will cause a change of mind, and point out specifically where the data and analysis fall short or are flawed. There is such a thing as false skepticism, where one's decision is not based on the relevant science, and that's where a lot of the denialist tactics come in. To paraphrase the old adage, you can pound on the data or pound on the science, but when you have neither, you pound on the table. Denialists do a lot of pounding on the table.
Pangloss Posted December 21, 2007 Posted December 21, 2007 That's just it, though. We have pointed out where arguments were wrong, and the posts have been ignored. Count up the number of times that Lance has stated that iNow "denied his data," (and all of the related claims) and the number of times that people have rebutted that. The really ironic thing here is that SkepticLance is not denying that the recent temperature changes are induced by human-generated CO2, and yet, there are claims that challenging his claims is politics and/or political correctness. If that were actually the case, there would be no argument — why criticize someone who agrees with you? The reality is that SkepticLance is being challenged because there are flaws in the analyses he's presented, which have been pointed out multiple times, to no avail. And conclusions drawn from invalid arguments are invalid (even if they end up with the right answer). There's nothing wrong with being skeptical. But a skeptic still has to follow the rules of science. A skeptic has to have a point where the quality and quantity of data will cause a change of mind, and point out specifically where the data and analysis fall short or are flawed. There is such a thing as false skepticism, where one's decision is not based on the relevant science, and that's where a lot of the denialist tactics come in. To paraphrase the old adage, you can pound on the data or pound on the science, but when you have neither, you pound on the table. Denialists do a lot of pounding on the table. I have no problem with any of that. I just think there's table-pounding going on by GW proponents/defenders as well, and unfortuantely that plays out as a lack of tolerance for any level of skepticism on any subject related to global warming. You say it's not about politics, but I completely disagree, I think this entire board, and everything we discuss here, 100% of the time, is politics. The vast majority of people who come in here, swansont, are here to TELL people something, not to listen to what other people have to say. That's political -- convincing other people that you're right and they're wrong. That's what we've been reduced to here at SFN when it comes to GW. We don't debate it. We evangelize it. And anybody who doesn't pay their obeisance at the altar is cast out. It's not QUITE useless, I admit. Users can still log in here and ask questions about global warming and receive scientifically valid (and polite, and helpful, and informative) answers. They can even raise questions and receive more answers. So long as they remain supplicants everything's fine, and that does have some value.
SkepticLance Posted December 21, 2007 Posted December 21, 2007 Let me comment on linearity vs exponential growth. Swansont comments on the fact that CO2 growth has approximated an exponential growth curve. That is correct. However, it is a simplistic conclusion to say that this means future temperature growth must also be exponential. First : the response to CO2 growth as temperature rise is not one to one. It is a reverse exponent. If CO2 rises as an exponent, it may well (in theory)result in a linear temperature rise. Since I do not have a crystal ball, I am not prepared to say whether this will or will not happen. It all depends on how dramatic is the CO2 rise in future. Second : if we look at temperature rise over the past 30 years, which covers a time of exponential CO2 rise, the result approximates a linear rise in temperature. Not exact, since the data shows considerable variation year to year. However, if we draw a suitable straight line through the data points, it fits the graph (for 30 years only) just as well as a slight curve. For this reason, we cannot conclude exponential temperature rise over the past 30 years. If we cannot do that, then we are out of line concluding it for the next 30. The simple reality is that I cannot, and neither can anyone else, predict whether future temperature rise is linear or exponential or anything else. Current temperature rise approximates a linear rise of 0.15 to 0.2 C per decade. This, to me, makes it likely that dramatic temperature rises are not likely in the near future.
Cap'n Refsmmat Posted December 21, 2007 Posted December 21, 2007 That's political -- convincing other people that you're right and they're wrong. No it isn't. That's the science part. I think you've been moderating the Politics board for too long. You're seeing politics in everything.
iNow Posted December 21, 2007 Posted December 21, 2007 CO2 vs warming. From 1976 to the present, this is crystal clear. Before that it is theoretical and mathematical, for the simple reason that other factors are overwhelming the effect of the CO2. Since the other factors cannot truly be quantified, that makes the whole thing murky. A climate scientist may say that, between 1930 and 1940 for example, the CO2 increase creates a certain warming. However, the warming at that time was far greater than the CO2 calculation would predict. Why? Because of the effects of other factors, with in this case, sunspot activity, being paramount. Note that from about 1910 to about 1940, there was a massive increase in sunspot activity. Since the mechanism by which sunspot activity causes warming of the Earth is poorly, if at all, understood, it cannot be calculated. Thus, for that time, things are murky. So, how many degrees +/- what we actual measure does "murky" translate into? Is +/- 1 degree over the century how you define "murky," or is it closer to +/- 10 degrees? Is murky measured using the metric system? What is the confidence rating of your scale, "murky?" Murky... GMAB. How about some numbers showing error, instead of (even more of your) unsupported claims and assertions. Stop painting with the broad brush strokes of doubt and start showing specifics to support your claims. It's been said already, but citations are important in supporting your claims, not your rhetoric. To your point about uncertainty in measurements before 1970, the instrumental record extends 140 years into the past. Just because these records were not captured using satellite technology does not mean they are invalid. 1970 is when satellite temperature readings began, but those which came before are still valid and accurate. If you claim otherwise, it's going to take more than your words to overcome the mountain of evidence which stands contrary to that claim. See more below: INSTRUMENTAL RECORD FOR PREVIOUS 140 YEARS: http://www.ncdc.noaa.gov/paleo/globalwarming/instrumental.html A set of temperature records from over 7,000 stations around the world has been compiled by the NOAA National Climate Data Center to create the Global Historical Climatology Network - GHCN (GHCN Version 2 data set; Peterson and Vose 1997). About 1,000 of these records extend back into the 19th century. GLOBAL TEMPERATURES OVER THE PREVIOUS 2,000 YEARS: http://www.ncdc.noaa.gov/paleo/globalwarming/paleolast.html Over the last decade, there has been a major breakthrough in our understanding of global temperature change over the last 1000 years. Several different but important studies, published in peer-reviewed scientific journals, revolutionized what we know about the 20th century in the context of past centuries. The research of the late 1990s formed the foundation for a progression of studies that followed, incorporating advances in statistical techniques and information from a broad range of proxy data types. GLOBAL TEMPERATURES FROM PRIOR TO 2,000 YEARS AGO: http://www.ncdc.noaa.gov/paleo/globalwarming/paleobefore.html The Earth has experienced other warm times in the past, including the Medieval Warm Period (approximately 800-1300 AD), the mid-Holocene (6,000 years ago), and the penultimate interglacial period (125,000 years ago). These warm periods are described in the sections below Paleoclimate for times before 2,000 years ago are also useful because they reveal the full extent of natural climate variability. These older records show that climate has changed abruptly in the past, and also reveal a remarkable correspondence between carbon dioxide change and temperature change during the Earth glacial cycles, described in the sections below. WHAT IS PROXY DATA? http://www.ncdc.noaa.gov/paleo/globalwarming/proxydata.html Proxy data is data that paleoclimatologists gather from natural recorders of climate variability, e.g., tree rings, ice cores, fossil pollen, ocean sediments, coral and historical data. By analyzing records taken from these and other proxy sources, scientists can extend our understanding of climate far beyond the 140 year instrumental record. It's interesting that many of your claims are the very ones used by deniers, claims which have already been debunked: http://www.skepticalscience.com/argument.php Notice how I support my points with evidence and citations? You should try it sometime. To your point about uncertainties and unreliability of models, this is yet another denialist approach which has been debunked: http://www.skepticalscience.com/climate-models.htm There is a notion that we should wait till models are 100% sure and get it perfectly right before we act on reducing CO2 emissions. If we waited for that, we would never act. Models are in a constant state of improvement as they include more processes, rely on fewer approximations and increase their resolution as computer power develops. The complex and non-linear nature of climate means there will always be refinements and subtleties to be included. The main point is we know enough to act. Models have evolved to the point where they successfully predict long term trends and are always improving on predicting the more chaotic, short term changes. Multiple lines of evidence tell us global temperatures will change 3°C with a doubling of CO2. The uncertainty is ±1°C degree but this uncertainty is decreasing (and the climate sensitivity of 3°C reaffirmed) as new studies refine our understanding. Models don't need to be exact in every respect to give us an accurate overall trend and its major effects - and we have that now. If you knew there was a 10% chance you'd be in a car crash, you'd wear a seatbelt. In fact, if there was any possibility, you'd still do it. The IPCC consider it at least 90% sure humans are causing global warming. Considering the negative impacts of global warming, to wait for 100% certainty before acting is recklessly irresponsible.
swansont Posted December 21, 2007 Posted December 21, 2007 Let me comment on linearity vs exponential growth.Swansont comments on the fact that CO2 growth has approximated an exponential growth curve. That is correct. However, it is a simplistic conclusion to say that this means future temperature growth must also be exponential. First : the response to CO2 growth as temperature rise is not one to one. It is a reverse exponent. If CO2 rises as an exponent, it may well (in theory)result in a linear temperature rise. Since I do not have a crystal ball, I am not prepared to say whether this will or will not happen. It all depends on how dramatic is the CO2 rise in future. Second : if we look at temperature rise over the past 30 years, which covers a time of exponential CO2 rise, the result approximates a linear rise in temperature. Not exact, since the data shows considerable variation year to year. However, if we draw a suitable straight line through the data points, it fits the graph (for 30 years only) just as well as a slight curve. For this reason, we cannot conclude exponential temperature rise over the past 30 years. If we cannot do that, then we are out of line concluding it for the next 30. The simple reality is that I cannot, and neither can anyone else, predict whether future temperature rise is linear or exponential or anything else. Current temperature rise approximates a linear rise of 0.15 to 0.2 C per decade. This, to me, makes it likely that dramatic temperature rises are not likely in the near future. But you did predict a linear increase (and exclude an exponential) ... If you assume that the higher part of the warming range (ie. 0.2 C per decade) is correct, then it will take 150 years for a 3 Celsius increase in average temperature on Earth. ... and that's been a point of contention for several pages of posts. Which statement are you going to stand by?
Pangloss Posted December 21, 2007 Posted December 21, 2007 I think you've been moderating the Politics board for too long. You're seeing politics in everything. But I've always seen politics in everything, so that's hardly anything new.
Mr Skeptic Posted December 21, 2007 Posted December 21, 2007 Why would you want to limit your data to that of the last 30 years to predict things more than 30 years in advance?
iNow Posted December 21, 2007 Posted December 21, 2007 Why would you want to limit your data to that of the last 30 years to predict things more than 30 years in advance? No reasonable person would. My sense is that limiting the data to the past 30 years is the only way that Lance can justify his conclusions regarding future trends.
SkepticLance Posted December 21, 2007 Posted December 21, 2007 To iNow I do not believe I ever said that temperature measurements before 1970 were inaccurate or unreliable. Could you please point out where I said that? As far as I can see, the entirety of your last post was to refute things I never said .... To Swansont Also it appears you are misreading my earlier posts. I try to make it very clear that predictions are uncertain. I do not think I ever said that future warming would be linear. What I have tried to say is that a major change in the near future is unlikely. This follows simply from the fact that the last 30 years have been approximately linear, and since long term trends rarely change rapidly, a change to dramatic exponential growth in the next 30 years is unlikely. Sure, it could happen, but if warming becomes exponential, after 30 years of almost linear, it will probably do so gradually. You quoted my statement : "If you assume that the higher part of the warming range (ie. 0.2 C per decade) is correct, then it will take 150 years for a 3 Celsius increase in average temperature on Earth. " Did you fail to notice the first three words? I clearly noted the assumption that deduction was based on. You are fully entitled to dispute the assumption, and I will freely admit that assumption is uncertain. The warming range could indeed rise above the 0.2 C per decade. However, I would ask you not to ascribe to my statement a clear message that future warming must be linear. I did not say that, then, and I am not saying it now. It is all based on probability. I regard, in light of history, it unlikely that we will see a major increase in warming in the near future. You can disagree, and no doubt will. Mr. Skeptic said : "Why would you want to limit your data to that of the last 30 years to predict things more than 30 years in advance?" The short answer is that I don't. I have been at pains to tell everyone that I do not believe accurate predictions can be made at all. Why the past 30 years? Because that is the only period in which a clear cut warming in response to greenhouse gases can be seen. Before that, the situation was difficult. (iNow has an objection to me using the word 'murky', which is a shame, since I think it describes the situation well.) More than 30 years ago the impact of greenhouse gas increase was much less, because greenhouse gas increase was much less. In addition, the impact of other factors, such as sunspot activity, and possibly aerosol pollution, was much stronger. Thus, global average temperature went up and down in response to those influences, masking any effect CO2 might have had. In the last 30 years, sunspot activity, vulcanism, and possibly aerosol pollution have been more consistent, allowing the impact of greenhouse gases to become clear cut. iNow said "My sense is that limiting the data to the past 30 years is the only way that Lance can justify his conclusions regarding future trends." I hope you realise that this is getting real close to the ad hom you accuse me of. Watch out for the chance that you might be getting a wee bit hypocritical.
swansont Posted December 22, 2007 Posted December 22, 2007 Also it appears you are misreading my earlier posts. I try to make it very clear that predictions are uncertain. I do not think I ever said that future warming would be linear. What I have tried to say is that a major change in the near future is unlikely. This follows simply from the fact that the last 30 years have been approximately linear, and since long term trends rarely change rapidly, a change to dramatic exponential growth in the next 30 years is unlikely. Sure, it could happen, but if warming becomes exponential, after 30 years of almost linear, it will probably do so gradually. You quoted my statement : "If you assume that the higher part of the warming range (ie. 0.2 C per decade) is correct, then it will take 150 years for a 3 Celsius increase in average temperature on Earth. " Did you fail to notice the first three words? I clearly noted the assumption that deduction was based on. You are fully entitled to dispute the assumption, and I will freely admit that assumption is uncertain. The warming range could indeed rise above the 0.2 C per decade. I saw them. They quantify the slope of a straight line. And you've clarified your statement. But that also means you can't exclude a result, either. If you can't predict, you can't predict. However, I would ask you not to ascribe to my statement a clear message that future warming must be linear. I did not say that, then, and I am not saying it now. It is all based on probability. I regard, in light of history, it unlikely that we will see a major increase in warming in the near future. You can disagree, and no doubt will. And I do disagree. I think you can predict, with some degree of accuracy. Even if one agrees with your objections about problems with the of multiple variables, it would seem that the changes of a single forcing, CO2, could yield reasonable predictions. "My sense is that limiting the data to the past 30 years is the only way that Lance can justify his conclusions regarding future trends." I hope you realise that this is getting real close to the ad hom you accuse me of. Watch out for the chance that you might be getting a wee bit hypocritical. No, that's not anywhere close to an ad hom. iNow is attacking your methodology (restricting a data set), not you.
iNow Posted December 22, 2007 Posted December 22, 2007 To iNow I do not believe I ever said that temperature measurements before 1970 were inaccurate or unreliable. Could you please point out where I said that? As far as I can see, the entirety of your last post was to refute things I never said .... You are correct. It appears that I misinterpreted your post. I thought you were challenging the temperature record previous to 1970, and that is a mistake. You clearly were not, and I apologize for my error. You were, though, AGAIN challenging our ability to understand the forcing from greenhouse gases and their concentrations prior to that time. What's frustrating here is your inability to realize that this has already been covered and this point proven invalid. I call your attention now to the following thread where you were using this same logic to prove sunspots had a greater impact, and also where you challenged the very concept of modelling. You were proven inaccurate at nearly every turn there as well, especially as pertains to our understanding or CO2 concentrations prior to 1976. http://www.scienceforums.net/forum/showthread.php?t=26669 It's your inability to acknowledge fault and drop invalid premises that is so frustrating. You seem incapable of amending your position when it's been proven false, and you instead keep repeating the same invalid claims as if they were never addressed. Repeating yourself does not add any validity to your claim.
Reaper Posted December 22, 2007 Posted December 22, 2007 SkepticLance, just because there was no dramatic increase in temperature in a little period in the past doesn't mean that it won't happen in the future. We have consistently shown you that your analysis is wrong, wrong, WRONG!!!! Especially since we know exactly how much it is changing by right now. ============================ As for the rest of the people on this thread, I admire your patients with this guy. Especially given the fact that he has been doing this sort of thing for over a year.
SkepticLance Posted December 22, 2007 Posted December 22, 2007 From Swansont " But that also means you can't exclude a result, either." Correct. However, what we are talking about are probabilities only. I consider it improbable that long term trends that are very consistent will suddenly change. Unless, of course, a new factor enters the situation. For the past 30 years, we have had a steady increase in CO2 and a similarly steady increase in temperature. If this continues, then we can expect the temperature increase to remain steady. I saw the opposite in Al. Gore's atrocious movie. He showed the current warming as a straight line, and then added another straight line at a much steeper angle as the prediction. Al. baby; it don't work that way! Of course, a new factor could easily enter. It has happened before. It happened in 1910 when sunspot activity suddenly increased, and a 30 year cooling turned into a 30 year warming. It happened again in 1940 when sunspot activity suddenly fell and the world cooled by 0.2C. Something similar could easily happen again, but the outcome would be as likely a cooling as a warming. iNow said "You clearly were not, and I apologize for my error." And thank you for the apology. My respect for you just went up ten notches. "You seem incapable of amending your position when it's been proven false, and you instead keep repeating the same invalid claims as if they were never addressed." The problem, iNow, is that you never present evidence that I can find convincing. I am not interested in the results of calculations or computer models, as I have made clear in the past. These cannot be reliable when we are dealing with a system that contains so many unknowns. As I said before, climate modellers cannot even yet accurately model the effects of variable cloud formation. How can they quantify climatic effects when such basics are not yet understood?
iNow Posted December 22, 2007 Posted December 22, 2007 "You seem incapable of amending your position when it's been proven false, and you instead keep repeating the same invalid claims as if they were never addressed." The problem, iNow, is that you never present evidence that I can find convincing. I am not interested in the results of calculations or computer models, as I have made clear in the past. These cannot be reliable when we are dealing with a system that contains so many unknowns. As I said before, climate modellers cannot even yet accurately model the effects of variable cloud formation. How can they quantify climatic effects when such basics are not yet understood? This has been covered already too. The models are quite valid and accurate, and are continually getting better. Cloud formation is a local event, whereas climate is a long term average. I cannot tell you how a flipped coin will land, but I can tell you on average how it will play out over 1,000 flips. This is the difference between cloud formation and climate trends. As has been addressed already in this thread, that is another denialist tactic that has been thoroughly debunked. The models work, whether you find the evidence personally convincing or not has no effect on their accuracy and predictive qualities, nor on the consistency with which different models tend all to lead to the same conclusions.
Pangloss Posted December 22, 2007 Posted December 22, 2007 ... whether you find the evidence personally convincing or not has no effect on their accuracy and predictive qualities, nor on the consistency with which different models tend all to lead to the same conclusions. A statement that ironically cuts in two directions, and for two reasons. Still, I agree with your point in that post, though I still remain unconvinced that your "proofs" are actually proofs rather than just educated (and politically influenced) opinions (and important evidence). Though I think I understand better now why you're frustrated.
SkepticLance Posted December 22, 2007 Posted December 22, 2007 iNow said : "Cloud formation is a local event, whereas climate is a long term average." Not true. Cloud formation MUST be influenced by the amount of water vapour in the air, and we know that warming increases water vapour. There is some satellite evidence that sunspots lead to more cloud formation. There is evidence from satellite studies that phytoplankton blooms over warm patches of ocean are associated with extra cloud cover. In other words, cloud cover and the type of cloud formation are variables that interact with surface temperature. How this feeds back into the whole system remains unclear. We know that low altitude cloud has a cooling effect, and there is some suggestion that high altitude cloud may be warming. None of these influences can currently be modelled by computers.
Reaper Posted December 22, 2007 Posted December 22, 2007 Still, I agree with your point in that post, though I still remain unconvinced that your "proofs" are actually proofs rather than just educated (and politically influenced) opinions (and important evidence). Though I think I understand better now why you're frustrated. Oi Pangloss! When are you going to learn that not everything is political. The climate models just predict what will happen; whether it is good or bad is a purely arbitrary value assigned by us.
iNow Posted December 22, 2007 Posted December 22, 2007 iNow said : "Cloud formation is a local event, whereas climate is a long term average." Not true. Cloud formation MUST be influenced by the amount of water vapour in the air, and we know that warming increases water vapour. This is quite irrelevant to the point, since I was (in fact) addressing your attempt to suggest that our climate models must be faulty because we have some unknowns in our cloud formation models. You said: These [climate models'] cannot be reliable when we are dealing with a system that contains so many unknowns. As I said before, climate modellers cannot even yet accurately model the effects of variable cloud formation. How can they quantify climatic effects when such basics are not yet understood? ... So your point above is a complete non-sequitur. First, the onus is on YOU to prove the impact of cloud cover, then to show how significant that impact is on overall climate relative to other forcing. Further, a presumed inability to model cloud formation has zero impact on past temperatures, past temperatures which our climate models very accurately represent. Past temperatures are recorded, and by definition include all forcing factors, including cloud cover and water vapour, and the climate models match up to historical records quite well. To jump from "we cannot accurately model cloud formation" to "the climate models CANNOT be reliable" is rubbish, and if you fail to see this, I'm afraid all dialog with you is for naught. You also seem to imply that the models of climate do not account for the effects of water vapor, which is FAR from the truth. If you did not intend to imply this, then I strongly caution you to choose your words more wisely in every future post you make. Specific to your suggestion that we cannot accurately model cloud formation, I'd like you to view the links below and give us all your very expert analysis where they fail, and why you deem them "inaccurate:" http://web.mit.edu/cgcs/www/clouds.html http://www.aos.wisc.edu/research/physics.htm http://www.agu.org/pubs/crossref/2003/2002JD002711.shtml http://www.met.tamu.edu/class/metr452/models/2001/precip.html http://www-pcmdi.llnl.gov/projects/modeldoc/amip/24lmd_b.html http://gtresearchnews.gatech.edu/newsrelease/cloudcover.htm http://www.cs.umbc.edu/~ebert/693/PChen3/paper.html http://www.arm.gov/publications/proceedings/conf08/extended_abs/zhang2_q.pdf http://citeseer.ist.psu.edu/330426.html http://adsabs.harvard.edu/abs/1999PhDT........12Z Those are just a few results from THE FIRST PAGE ONLY of my google search. There were scores more, and I'd be glad to share them with you if needed. Perhaps once you've finished illustrating all of the inaccuracies in the above, we can move on to the rest? That seems fair enough, right? After all, it would help you to support your claim that "we cannot accurately model cloud formation," so it would turn out to be beneficial to your argument and assertions. You see, Lance, you keep making these assertions, and your assertions are continually shown wrong. Claim after claim, statement after statemen of yours is shown to be false, inaccurate, and misrepresentative of the actual state of things. Your assertions continually do not stand up to scrutiny, and you fail to support a significant percentage of what you say with any evidence whatsoever. Then, once evidence comes to light, the vast majority of your assertions and conclusions are debunked. I am not attacking you, let's be clear on that. I am attacking your consistent inability to make claims which hold water and stand up to analysis. Too frequently your posts are laden with inaccurate and unsupported claims, misrepresentations and false premises, and your conclusions which are rooted in those falsehoods themselves are fallacious. [borrowed from a recent article in the BBC News by Richard Black] If someone persistently claims to be a great football player, and yet fails to find the net when you put him in front of an open goal, you cannot do other than doubt his claim. The goal is right in front of you, but you keep missing the net, mate.
SkepticLance Posted December 22, 2007 Posted December 22, 2007 To iNow The problem of cloud formation is not one that I have invented. It was a major topic of discussion in the international conference on climate modelling about 3 years ago, as reported in New Scientist. Australian printed edition. 24 July 2004 page 45. I quote : "While clouds have always been regarded as one of the biggest uncertainties in calculations of global warming, they are turning out to be more of a wild card than anyone imagined. The fear is that global warming will either reduce how cloudy the planet is, or significantly change the type of clouds in the sky, and their influence of the planet's radiation budget." Also " Clouds are clearly linked to water vapour. A lot of water vapour in the air eventually forms clouds. During their short lives clouds produce both positive and negative feedbacks." And so on. The tone of this article is negative and alarmist, which is normal for New Scientist. However, the admission is there, that clouds are a major unknown with unknown effects. Thus, the uncertainty in global climate models. As far as testing the accuracy of climate models - Bascule posted a bunch of graphs showing climate model back models for aspects of climate over the past 100 years. The models were very good at modelling the last 30 years, but got progressively worse beyond that. As I have said, the past 30 years were a very simplified case, and should be easy to model. A good model needs to do better than just that.
swansont Posted December 22, 2007 Posted December 22, 2007 Note that something can be the "largest uncertainty" and still be smaller than the contibution with which it's associated. The description tells you nothing of its actual magnitude. From Swansont " But that also means you can't exclude a result, either." Correct. However, what we are talking about are probabilities only. I consider it improbable that long term trends that are very consistent will suddenly change. Unless, of course, a new factor enters the situation. For the past 30 years, we have had a steady increase in CO2 and a similarly steady increase in temperature. If this continues, then we can expect the temperature increase to remain steady. But that's still assuming that the system is linear. To exclude results, you have to have a physical basis for doing so. Which means quantifying effects, and that means modeling it. Without that, any prediction is baseless. I saw the opposite in Al. Gore's atrocious movie. He showed the current warming as a straight line, and then added another straight line at a much steeper angle as the prediction. Al. baby; it don't work that way! But it does work if the slope had stayed the same? AFAIK the graph was predicting what would happen of CO2 kept increasing at its exponential rate. Without reference to the actual curve, and the model & data it's based on, you really can't say one way or the other. Of course, a new factor could easily enter. It has happened before. It happened in 1910 when sunspot activity suddenly increased, and a 30 year cooling turned into a 30 year warming. It happened again in 1940 when sunspot activity suddenly fell and the world cooled by 0.2C. Something similar could easily happen again, but the outcome would be as likely a cooling as a warming. But the context here is a doubling of CO2; what is the effect of that? The prediction is conditional. Other factors will have different effects, but they, too, can (and must) be quantified. But it's perfectly valid to estimate the effect of a single forcing, that being a doubling of CO2.
iNow Posted December 22, 2007 Posted December 22, 2007 To iNow The problem of cloud formation is not one that I have invented. It was a major topic of discussion in the international conference on climate modelling about 3 years ago, as reported in New Scientist. Australian printed edition. 24 July 2004 page 45. I quote : "While clouds have always been regarded as one of the biggest uncertainties in calculations of global warming, they are turning out to be more of a wild card than anyone imagined. The fear is that global warming will either reduce how cloudy the planet is, or significantly change the type of clouds in the sky, and their influence of the planet's radiation budget." Also " Clouds are clearly linked to water vapour. A lot of water vapour in the air eventually forms clouds. During their short lives clouds produce both positive and negative feedbacks." And so on. I dont' disagree with the above. Where I challenge you is in the changing of the context in which this discussion of clouds arose. You explicitly stated that one cannot trust climate models because we cannot with full accuracy model cloud formation. Then, AGAIN, despite the fact that this has already been deemed a non-sequitur and despite the fact that you have not established either the scope or the relevance of cloud formation models on climate models, you then go on to assert the same damned thing: The tone of this article is negative and alarmist, which is normal for New Scientist. However, the admission is there, that clouds are a major unknown with unknown effects. Thus, the uncertainty in global climate models. Just because you keep saying something does not make it valid. I asked you several posts again to support your contention, and you have not. I have shown evidence suggesting that your contention is not relevant and is a non-sequitur, and you have not overcome or disproven that evidence. You have simply repeated yourself as if evidence was not presented. Let me make this easy: WHAT IS THE SCOPE OF THE IMPACT ON GLOBAL CLIMATE MODELS FROM UNCERTAINTIES IN CLOUD FORMATION MODELS? Once you've established that, THEN it would be appropriate to use it in your responses, but not before. Additionally, you have ALSO failed to identify SPECIFICALLY which cloud formation models are not accurate and why. You have blanketly stated that cloud formation models fail, and yet you have offered ZERO specifics on which ones and why. Your link to a conference discussing how to improve feedback in some models was interesting, but it failed to show both the potential scope of the impact and how this is AT ALL relevant to the climate models you are challenging on the basis of this cloud formation model incompleteness. As far as testing the accuracy of climate models - Bascule posted a bunch of graphs showing climate model back models for aspects of climate over the past 100 years. The models were very good at modelling the last 30 years, but got progressively worse beyond that. As I have said, the past 30 years were a very simplified case, and should be easy to model. A good model needs to do better than just that. You mentioned that you did not challenge the temperature record prior to 1970. On this we clarified with each other. It's also been amply demonstrated that the climate models successfully present results well aligned with those temperature records. So, how is it, precisely, that you feel the climate models fail? You're not making much sense now. Temperature record, no problem. Climate models, accurately represent temperature. then, you say... Climate models are not accurate. What do you suggest is being missed? Your conclusion is not logical AT ALL. Are you even reading the posts, Lance? You continue arguing against issues that have been very well established. Your arguments continue to make these challenges with no specifics or support. Your challenges, despite being presented with no evidence, being misrepresentative and of little validity, are also based on faulty logic. You may claim not to be a denialist, but your actions speak louder than your words.
Reaper Posted December 22, 2007 Posted December 22, 2007 I would also like to note that there are cave paintings which give a reliable account on what the climate may have been like at the time that they were put on the walls. And, many of these have indeed been verified by physical evidence. This shows even more reason to trust the climate models and the measurements taken for the past and present. I think, SkepticLance, that this now just puts your assumptions out of the frying pan and into the fire. Unless, of course, you can provide any evidence to the contrary. And, read, EVIDENCE. More specifically, PHYSICAL EVIDENCE, or a PEER-REVIEWED paper, or DATA. That should be easy enough, shouldn't it? Otherwise, I don't see why you still cling on to your mistaken assumptions, especially since you even admitted that the data provided did actually predict some pretty dire consequences should our problems continue to go unchecked...
SkepticLance Posted December 22, 2007 Posted December 22, 2007 It is almost ironic. People like iNow are ignoring what I am saying and accuse me of ignoring what they are saying. To iNow Re clouds. Clouds are ONE uncertainty in computer models. There are lots of unknowns. What I am saying is that this demonstrates that models are not completely reliable. Clouds are an unknown that has received some publicity. Other sources of uncertainty are still too poorly understood to even get much publicity. Such as biological effects on climate. And, no. I do not need to quantify the uncertainty. That is why it is called uncertainty. Because it can't be quantified. Once it is understood well enough to be quantified, it will no longer be an uncertainty. I gave a good reference to the fact that uncertainties over cloud formation generate uncertainties in computer models. iNow is repeating history. Because he does not like the fact that there is evidence against his assertions, he is just riding over it - essential ignoring the evidence. The whole point is that it is not possible to accurately predict the future. We can talk about probabilities. But that is all. Anyone who thinks that they can do more is engaged in intellectual auto-eroticism. iNow said ; "So, how is it, precisely, that you feel the climate models fail?" Do you remember the graphs bascule posted? I should have kept them to post again, but didn't. They showed a good correspondence within acceptable error levels with warming over the past 30 years. However, their simulation of the years before that were not good. In some places, they were way out. I would personally be very surprized if the last 30 years could not be reasonable well modelled, since the pattern was so straight forward. When things got complex, the models failed to simulate them with any accuracy at all. Lockheed is demanding evidence. I have given evidence of uncertainty in the impact of cloud formation. However, because it cannot be quantified, it cannot be 'proven'. On the other hand, if you have a reliable and accurate technique, it can be quantified, and therefore generate evidence. The onus is on you to produce that evidence. To Swansont Re Al. Gore Al Gore showed a temperature graph that was discontinuous. I accept that the rate of temperature rise may increase. It may also decrease, but an increase is possible. However, if it increases, it will do so in a gentle curve. Gore showed two straight lines and a sharp corner. I was pointing out that does not happen in nature. Al. Gore, like many other climate catastrophists, is basically dishonest, and misrepresents the science. You keep going back to claiming that I believe warming to be linear. What I have said is that it approximates linearity for the last 30 years, and it is improbable that a major change will happen in the near future. ie. based on trends, it will probably not vary much from the current pattern for a while. It may turn from an approximately linear pattern to a gentle curve, but dramatic changes are not so probable.
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