tag:blogger.com,1999:blog-5337555368793819627.post5353301295047494661..comments2023-06-07T09:04:36.390-04:00Comments on More Grumbine Science: Does CO2 correlate with temperature?Robert Grumbinehttp://www.blogger.com/profile/10783453972811796911noreply@blogger.comBlogger36125tag:blogger.com,1999:blog-5337555368793819627.post-68424214698866269932011-10-17T18:57:30.823-04:002011-10-17T18:57:30.823-04:00Anon:
I'll take this up at more length in a fu...Anon:<br />I'll take this up at more length in a full post of its own. <br /><br />In the mean time ...<br />a) We expect that the dependence of temperature on CO2 would be logarithmic if CO2 were the only greenhouse gas. It isn't the only greenhouse gas, so the results may well be different than logarithmic. In the post I'll show you this, and some other, related, points.<br /><br />b) I don't really follow your comment about prediction. Nobody I know, and certainly not me, is making predictions about climate change based on just extending a correlation, whether of a linear function or a logarithmic one. The relationship here suggests another 3 C warming for going from 400 ppm (which we're almost at) to 700 ppm. That give about 4 C for the increase from 280 to 700 ppm. Probably on the low side of more detailed estimates. In the full post, I'll see what is suggested if we look at a logarithmic dependence.<br /><br />In the mean time, I'll also point to going the other way. That actually shows the logarithmic effect better. The 100 ppm rise from 280 to 380 gives about 1 C warming in the simple regression. The 100 ppm decrease from interglacial to glacial corresponds to 5 C cooling. Not all the cooling is due to lower CO2 in glacial periods. Some is the change in the earth's orbit, and some is from growing ice sheets (which then reflect solar energy). Still, some of the 5 C is indeed CO2-related.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-53611306774935153052011-10-15T09:29:40.710-04:002011-10-15T09:29:40.710-04:00I find it hard to believe the correlation is linea...I find it hard to believe the correlation is linear. It is easy to show that logarithmic is good also if not better. And that is a big difference in prediction. Say 1.9 deg up from 2010 level at 700 ppm Co2Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-84575318490862509442010-11-30T18:00:57.815-05:002010-11-30T18:00:57.815-05:00A reminder to commenters -- I note myself that the...A reminder to commenters -- I note myself that the only thing the article demonstrates is that the two are correlated. I do that because there are people saying that they aren't. It's rather trivially false, as the article showed.<br /><br />To show causation does indeed take a lot more work. That's why the attribution problem is the subject of many papers.<br /><br />most recent anon:<br /><br />The value of the slope has nothing to do with the correlation. (The sign does.) You cannot change the correlation by changing the graph's scale. Take your software of choice and compute the correlation for this set:<br />1, 1<br />2, 2<br />3, 3<br /><br />and then for this set:<br />1, 100<br />2, 200<br />3, 300<br /><br />The correlation is the same. The slope is different because I rescaled the y axes. But correlation is identical.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-71860183895628294482010-10-17T13:19:21.579-04:002010-10-17T13:19:21.579-04:00The one thing that is wrong with your analysis is ...The one thing that is wrong with your analysis is the graph itself. Anyone can select the scale to fit whatever outcome they would like to see...in this case it is slope.<br /><br />I would propose that to find what the true correlation is, have both axes scaled at the same proportion. If you do that the graph and "trend line" will be much flatter and the end result will be different than what you have shown.<br /><br />Another point is that while a correlation might appear to exist, you have failed to identify what causes what. Higher temperatures releases CO2 from the ocean placing more CO2 into the atmosphere and voila, you have a correlation but the rise in temp is driving the rise in CO2.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-20038742681659721552010-08-31T00:38:44.088-04:002010-08-31T00:38:44.088-04:00I am no scientist but I have a biologist friend wh...I am no scientist but I have a biologist friend who told me that these changes are partly the result of a natural cycle. I do not want to minimize the damege the we as people made, but I believe that climate change is a result of several factors not just one like CO2news gameshttp://www.gnews.ro/noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-29056102857645528212010-05-11T21:09:55.741-04:002010-05-11T21:09:55.741-04:00Nice example of "correlation is not causation...Nice example of "correlation is not causation".<br /><br />You need to, at the least, combine anthropogenic forcings from sulfates with CO2. For much of the instrumentation period they had nearly equal values but opposite signs.<br /><br /><a href="http://data.giss.nasa.gov/modelforce/RadF.txt" rel="nofollow">I'd suggest using something like this</a>.<br /><br />The idea is a direct correlation between CO2 and temperature is a very unphysical assumptino.Carrickhttps://www.blogger.com/profile/03476050886656768837noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-73387000101926290382010-04-12T13:16:19.335-04:002010-04-12T13:16:19.335-04:00It is not very surprising to me that there is a co...It is not very surprising to me that there is a correlation between CO2 concentration and the deviation of the temperature from some chosen baseline. Fine, as it is clearly stated that it is a correlation, saying nothing about causation. It is therefore reasonable to also look at other interesting correlations.<br /><br />While it is the stated objective to contradict people who say 'there is no correlation between CO2 concentration and temperature' I would rather look for additional value in the exercise.<br /><br />My point is that there is a much better correlation between the Solar Wind AA Index and temperature than there is between CO2 and temperature.<br /><br />When it comes to suggesting causation, viewing the two correlation charts gives credence to the suggestion that Solar activity primarily drives the temperature and the CO2 level is an effect, certainly historically. To suggest the opposite, that CO2 is primarily responsible and the Solar Wind is an effect is implausible.<br /><br />Thus the CO2-Temp correlation graph has additonal value in context, not just as a point of refutation without really getting into the obvious implications for causation.Crispin in Waterloohttps://www.blogger.com/profile/11321228185258925385noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-82468458342738047282010-03-29T14:23:10.930-04:002010-03-29T14:23:10.930-04:00http://blogs.nature.com/climatefeedback/2008/08/mo...http://blogs.nature.com/climatefeedback/2008/08/more_for_the_annals_of_climate_1.html<br /><br />-------excerpt follows-------<br /><br />More for the annals of climate misinformation<br /><br />I’m all for a website that distills climate science papers into something easily understood by the general public, especially if it avoids the hype and hysteria all too often employed by headline news.<br /><br />Such is the claim of CO2 Science, a weekly newsletter published by the not for profit Center for the Study of Carbon Dioxide and Global Change, with issues that include editorials, book and media reviews, and mini-reviews of the recent peer-reviewed literature.<br /><br />But rather than its promise of “separating reality from rhetoric in the emotionally-charged debate that swirls around the subject of carbon dioxide and global change”, on the contrary CO2 Science twists the most recent science, ever so subtly, to suggest that there is no link between carbon dioxide levels and climate change.....<br /><br />---end excerpt----Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-84502148652749737182009-12-03T12:59:33.744-05:002009-12-03T12:59:33.744-05:00BTW, let me plug my own analysis where I address e...BTW, let me <a href="http://residualanalysis.blogspot.com/2009/12/statistical-proof-of-anthropogenic.html" rel="nofollow">plug my own analysis</a> where I address exactly that.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-3462757661368375202009-12-01T13:00:44.899-05:002009-12-01T13:00:44.899-05:00I'm surprised no one brought up pirates vs. te...I'm surprised no one brought up pirates vs. temperature. That's the straightforward criticism of this type of analysis. You have two non-stationary series trending upward. That they associate is not surprising. It could be coincidence. There are ways to address this.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-23319217755227646802009-05-19T14:56:00.000-04:002009-05-19T14:56:00.000-04:00DCM: The correlation may or may not mean anything....DCM: The correlation may or may not mean anything. More work is required to establish whether it does. But, for those who claim that there's no correlation, this is a straightforward demonstration that they're wrong.<br /><br />Your second para is seriously wrong in two different ways. First part is the sampling problem. Taking 130 years of climate out of the 4.55 billion years of earth history is 1 part in 35 million. 1 droplet of water is about 1 milliliter, so the comparable sampling is 1 droplet out of a 35 ton tanker. The ocean is 1.4e18 tons. You have exaggerated by a factor approaching a hundred-thousand-million-million times. In practice, we often <I>do</I> examine tankers from single drops, or the waters of a large harbor from a bottle sample.<br /><br />You continue that even the entire history (it's now closer to 800,000 years) of the ice cores is too little. For some issues, it would be. But ... the entire span of our species is markedly less than even that 'short' period. If you want to hold the position that anything short compared to the age of the planet is ignorable, fine. But you then must consider that it's ok to exterminate our species. <br /><br />I disagree rather strongly with that approach. So, tell me, what was the population of New York City 2 million years ago? 120,000 years ago? Does the climate then tell you that modern New York City of 8 million people would be just fine regardless of all possible climates? It certainly doesn't tell me that. All that the paleoclimate record tells you in that respect is that life on earth has survived all climates of the last 3.5-3.8 billion years. Nobody, certainly not me, is saying that all life on earth will be killed. I just think it would be bad to seriously disrupt life for the soon to be (and never before experienced) 7 billion humans on the planet.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-9917181178192802422009-05-18T23:28:00.000-04:002009-05-18T23:28:00.000-04:00My issue is (and you somewhat addressed it) is tha...My issue is (and you somewhat addressed it) is that I can correlate many things extremely well but they do not mean anything. If you look at public school test scores and average per capita income in that school - there is an extremely high correlation. But what does it mean? Nothing - it doesn't tell you if those classroom ahve small class size, or that higher income people have smarter children, etc. So when anybody just says "Look at the graph, its obvious that CO2 is causing temperature increase" - its just not that simple.<br /><br />Secondly, taking roughly 130 years of data and analyzing climate change is like taking a drop of water from a lake, looking an the pollutants and determining that is what every drop of water on our planet is like. Even using ice course for 600,000 years is still only 0.00013% of the history of the earth. The earth has been much hotter than it is today some estimate that at one point was 27C warmer approx 2mya.DCM5150noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-86243462516880569332009-05-03T09:45:00.000-04:002009-05-03T09:45:00.000-04:00Penguindreams said "we've been observing not only ...Penguindreams said "we've been observing not only the amount of CO2 in the atmosphere, but the composition of the carbon (the 3 isotopes) in the CO2. The isotopes carry the fingerprint of human activity, in particular burning fossil fuels and making cement."<br /><br />Horatio looked into the carbon isotope issue a bit in <A HREF="http://halgeranon.blogspot.com/2009/04/of-upward-slopes-and-isotopes-2.html" REL="nofollow">Upward Slopes and Isotopes</A> and would simply have to say at this point that those who <I>challenge</I> the claim of scientists that "CO2 emissions from fossil fuel burning are primarily responsible for the significant rise in atmospheric CO2 concentration in recent times" are simply ignorant of the science (at best). <br /><br />(and, by the way, the Schloerer FAQ <I>is</I> an excellent introduction)Horatio Algeranonhttps://www.blogger.com/profile/12988805467080448954noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-61402802427011680352009-04-21T14:17:00.000-04:002009-04-21T14:17:00.000-04:00Anon: I'm not assuming that 'is correlated with' m...Anon: I'm not assuming that 'is correlated with' means 'causes'. That's one of the reasons I do mention that we don't approach the problem this way in the science.<br /><br />It was reasonable -- to about 50 years ago -- to hypothesize that CO2 might just be responding to temperature increases, or any of a number of other parts of the climate system. Since then, however, we've been observing not only the amount of CO2 in the atmosphere, but the composition of the carbon (the 3 isotopes) in the CO2. The isotopes carry the fingerprint of human activity, in particular burning fossil fuels and making cement. For more detail on how this was figured out, see Jan Schloerer's <A HREF="http://www.radix.net/~bobg/" REL="nofollow">CO2 Rise FAQ</A>.<br /><br />So, for the rise of the last 150 years, no, it is no longer supportable to hypothesize that the CO2 is responding to the climate system. Humans have taken over control of the CO2 trend. <br /><br />The 'historical' charts you're referring to, if you are seeing some from the science, are charts for ice ages. I'm hard pressed to consider 4,000-800,000 years ago to be historical. But it is indeed information about the climate system. It tells us that <I>absent</I> significant human activity, CO2 feeds back on temperature. The ice age cycles themselves were driven by orbital variations. But the CO2 amplified the effects of the orbital changes.<br /><br />Since you're an engineer, you can easily carry out your own lead/lag experiment on the data I used. The correlation I gave was for zero lead/lag. I actually computed the correlation for CO2 leading temperature by 10, 20, 25 years -- and it was higher than for 0 lead. But pull down the data yourself, I do give the links, and compute the correlations over the past 160 years for leads of -30, -25 ... +30 years.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-40947574527623013942009-04-20T19:44:00.000-04:002009-04-20T19:44:00.000-04:00The problem with the discussion here is the implic...The problem with the discussion here is the implicit assumption that "is correlated with" means the same as "causes". I've worked in engineering for 30 years and seen many instances in which missile system bugs were chased for lengthy periods of time because the symptoms were correlated with something that turned out to be a coincidence. Pharmaceutical trials are carefully designed to remove biases due to coincidental correlations. I understand that the climate does not lend itself to traditional experimentation, but that does not excuse public policy makers from taking the relative lack of rigor involved in climate studies into account. Also, many charts depicting historic temperature versus CO2 levels appear to show that temperature changes <I>lead</I> CO2 changes. It's difficult to perceive a causal relationship there when approaching the problem without a preconceived conclusion. Is it not just as reasonable to theorize that temperature changes cause CO2 level changes?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-36625514118544167712009-04-14T08:29:00.000-04:002009-04-14T08:29:00.000-04:00I see that it'll be a good thing to write up a lit...I see that it'll be a good thing to write up a little note on correlation, what it does or doesn't mean, and what one can or can't do with it.<br /><br />Joseph, the details you point to don't contradict at all the results I present. The linear correlation at zero lag (temperature and CO2 for the same year) is as I said. Your real argument isn't that this correlation doesn't exist. It is that you can get a higher correlation by using logarithm of CO2, and by looking at CO2 leading temperature changes by about 10 years. That's entirely consistent with the results I show. It's also expected physically that the response will be logarithmic, rather than linear, and a 20 or so year lag for temperature to catch up to CO2 levels.<br /><br />As a statistical matter, you'd need to show that the 10 year lead/lag between temperature and CO2 gave a meaningfully better result than the zero lead/lag. Simple logarithmic response is no more complex, statistically, than linear, so you only need to show that it sits above the error bars of the linear function. If you used a more complex function than straight line (such as parabola), you'd also need to show that the extra complexity also gave enough of an improvement to justify the extra work. (F test)Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-65659521419778588452009-04-13T15:58:00.000-04:002009-04-13T15:58:00.000-04:00To play the contrarian here, I'd point out that CO...To play the contrarian here, I'd point out that CO2 doesn't really correlate with temperatures in that manner. <BR/><BR/>It's more like this: The logarithm of the CO2 concentration correlates with the <I>equilibrium</I> temperature. <BR/><BR/>It takes some time for the actual temperature to reach the equilibrium temperature. In fact, there's a lag of about 10 years between CO2 fluctuations and temperature fluctuations (I've seen this in the <A HREF="http://bp3.blogger.com/__6PO0G1BcJM/SHjWm0gCguI/AAAAAAAAACk/BsbMNnwz0Go/s1600-h/figure2b.JPG" REL="nofollow">historical data</A>, and I've also simulated it.)<BR/><BR/>I have a <A HREF="http://bp0.blogger.com/__6PO0G1BcJM/SJR-HpXwq1I/AAAAAAAAAEk/ryhLi7H4hko/s1600-h/new-150-hindcast.JPG" REL="nofollow">150-year hindcast</A> model that is based solely on (log of) CO2, which calculates not the temperature, but the rate of temperature change. It works.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-5132546518834013682009-04-11T17:03:00.000-04:002009-04-11T17:03:00.000-04:00Gary (not posted): 1) Please put your comments on ...Gary (not posted): <BR/>1) Please put your comments on the threads they're about. Your followup of the thread on 20 who claim CO2 does not correlate with temperature belongs over there, not here.<BR/><BR/>2) Before trying to repost, pay a little more attention to what the claims are about. My examination here was about correlation w. temperature during the period of humans driving the CO2 changes. Of course, then, I looked for sources which looked at this short span, vs. the thousands and up year periods. That's what's relevant to the claim. It would also be easy to make it 20 who claim there's no correlation during the ice age cycles either, but that's a different matter.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-9121114212526926122009-04-11T16:56:00.000-04:002009-04-11T16:56:00.000-04:00Gary (comment up 2):If climate were to show a cool...Gary (comment up 2):<BR/><BR/>If climate were to show a cooling, then I'd agree that climate had shown a cooling. If weather shows a cooling (which, interestingly, it doesn't for either the 10 years 1998-2007 or 1999-2008 -- slopes from annual average UK global means are positive for either 10 year period), then I'll agree weather shows a cooling.<BR/><BR/>But I won't agree that a weather cooling means climate cooling. See my earlier post <A HREF="http://moregrumbinescience.blogspot.com/2009/01/results-on-deciding-trends.html" REL="nofollow">Results on deciding trends</A>, which shows why you need 20-30 years to be speaking of a climate trend. The temperatures of the last 20, 30, 40, ... years show a warming trend. So climate is warming.<BR/><BR/>There are quite a few people who claim that humans are not causing the observed increase in CO2. Now that you're agreeing that, indeed, humans drove the CO2 changes of the last several decades (why do you start your clock in 1940, rather than the early 1800s of the scientists studying the topic?) you should understand why it is meaningful to look at this period separately from the period when humans were not driving the CO2 changes.<BR/><BR/>With that in hand, you should also understand why the lead/lag relationships during the ice core era are not useful, or at least not useful in the way you seem to think. The ice core CO2 lagging temperature, plus the rest of that story, shows that CO2 feeds back on temperature. Warmer temperatures give more CO2, which gives more warming. In the present context, however, humans cause the CO2 increase. The same feedback, though, means more warming, more CO2, etc. This amplification is not part of the standard climate models, so they are, if anything, underestimating the expectable change.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-47462857191332593012009-04-11T16:41:00.000-04:002009-04-11T16:41:00.000-04:00If you go to the comment Barry referred to, Evans ...If you go to the comment Barry referred to, Evans says:<BR/><I><BR/>If only there was a correlation between atmospheric CO2 and temperature! AGW asserts that there is a linear relationship between CO2 levels and temperature: as Gore said in his movie, the higher the CO2 level the hotter the temperature. Therefore if AGW was correct there would be a (linear) correlation between CO2 and temperature – correlation is not causation, but a lack of correlation proves there is no linear causation.</I><BR/><BR/>He's also wrong about anyone in the science expecting a linear relationship.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-74970477152603499922009-04-10T17:18:00.000-04:002009-04-10T17:18:00.000-04:00Regaridng this statement by Anon"Non-correlation o...Regaridng this statement by Anon<BR/><BR/>"Non-correlation of CO2 and temps is also being posited by David Evans. His evidence for non-correlation spans a much greater period, though. See comments, particularly post 87:<BR/><BR/>http://joannenova.com.au/2009/04/03/global-warming-a-classic-case-of-alarmism/"<BR/><BR/>I see this all over the place. He does not say that there is no corealtion. He says that there is good but lagging coreltaion on the 1000's of years and hundreds of thousands of years time scales and that there is not corelation on the 10's of years and the millions of years.<BR/><BR/>He then points out that there should be corelation on all time scales and that there isn't. He is not saying there isn't any corealtion, just that there isn't on every time scale, which is evidence (not proof but evidence) that temp is not as driven by global warming as we are being told by the alamists.<BR/><BR/>He is also pointing out that the theorectical (and generally accepted) relationship is logarithmic, causing a decreasing effect on temperature from CO2. These are arguments against the sharp increase of temps predicted by Al Gore and others based on a straight line correlation.garybucher@aol.comnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-34642529076362897842009-04-10T17:02:00.000-04:002009-04-10T17:02:00.000-04:00Also, the vostok ice core does show warmer temps i...Also, the vostok ice core does show warmer temps in 2 out of the last 3 ice ages then we have now. Your statement that we are much warmer than in the last 650,000 years is wrong.<BR/><BR/>Regarding temperature never drving CO2 above 300 - That is irrelevant. No one (or no one with any respect) is arguing that CO2 increase since 1940 has not been caused by people. What they have said is that this increase is not the main cause of warming. <BR/><BR/>I don't understand your paragraph stating that I need to show that CO2 in the last 150 years is driven by temperature variations. This is a dynamic world and a lot of things affect both temp and CO2. Some may drive both and man has added a lot of CO2. You need to show that CO2 drives temp before you ask me to modify my life style, pay more taxes, etc. No one has done that. If I was asking you to make a lifestyle change for a theory that said that CO2 does not affect the sun with no proof, you may be correct.<BR/><BR/>There is a much stronger case that Solar activity increase keep gamma rays from reaching the atmosphere which inhibits cloud formation, which increases the temperature on earth, along with the much smaller impact of greater warmth from the sun at the same time. The corelations between solar activity and temp are strong and there is a mechanism other than just increased heat that has been verified by experiemnts.<BR/><BR/>Who would ever think that we should consider changes to the sun as the cause of changes in earth's temp? <BR/><BR/>One final word: The head of the Hadley Center said a while back that decreasing global temperatures are not evidence against global warming. It is an argument similar to the one you are making. I understand that cooling temps are not proof that global warming has stopped, but can you at least admit that cooling temperatures are evidence that warming has stopped?Gary Buchernoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-73567493194969643012009-04-09T21:38:00.000-04:002009-04-09T21:38:00.000-04:00Non-correlation of CO2 and temps is also being pos...Non-correlation of CO2 and temps is also being posited by David Evans. His evidence for non-correlation spans a much greater period, though. See comments, particularly post 87:<BR/><BR/>http://joannenova.com.au/2009/04/03/global-warming-a-classic-case-of-alarmism/<BR/><BR/>I've been enjoying chatting to him there and will draw his attention here. Nice to talk to a polite critic with interesting points to make.<BR/><BR/>barryAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-62530856376320180962009-04-09T14:53:00.000-04:002009-04-09T14:53:00.000-04:00Gary: The 'who' is answered in the first two parag...Gary: The 'who' is answered in the first two paragraphs -- co2sceptics, who renamed themselves climaterealists. I did not make them up. Please do follow anonymous over to that site and educate them about the reality of there being a correlation.<BR/><BR/>It's nice to see someone provide, finally, a citation. But it will be better to see one that is relevant. The question at hand is not the last 2.5 million years (the Pleistocene of your source), but the last 150 years. Over the Pleistocene, the climate has mainly been driven by variations in the earth's orbit -- the Milankovitch cycles. For long time averages, where long has to be thousands of years, that's very important.<BR/><BR/>What you need to provide is a scientific source that the CO2 variations of the last 150 years are driven by temperature variations. While at it, disprove the anthropogenic source for the atmospheric CO2 increase (see Schloerer's document for a start on the scientific literature involved).<BR/><BR/>You'll also do well to observe that the 'temperature drives CO2' mechanism never did take CO2 levels over 280-300 ppm, while they're now over 380. Are you contending that temperatures are vastly warmer than any time in the last 650,000 years (the span covered by the source you cite)?<BR/><BR/><BR/>David:<BR/>If two variables (let's say A and B) show a correlation, and it's siginificant, then one usually has 3 options: A drives B, B drives A, both A and B are driven by something else. That collection of options is why, as I observed both early and late in the post, we don't do the science this way. I only observe that the two are correlated, contrary to the assertion from co2sceptics/climaterealists. They're not the only ones saying it, but were the ones that prompted my note.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-76646100727987961712009-04-09T14:19:00.000-04:002009-04-09T14:19:00.000-04:00Haven't read your analysis in detail but it looks ...Haven't read your analysis in detail but it looks very thorough. I do agree that CO2 concentrations have increased and think that CO2 correlates with temperature but does your analysis exclude the possibility that increasing temperature is driving the increase in CO2?dbleader61https://www.blogger.com/profile/10821463917415577147noreply@blogger.com