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Comments 84401 to 84450:

84401. Eric the Red at 00:33 AM on 1 June 2011
       Can we trust climate models?
       Tom, I agree that given accurate forcings, we can make accurate temperature predictions. Therein lies the main question: How accurate are our predictions of the forcings? Yes, we can control CO2. We can also control many other manmade factors. But, what is the normal range of natural variability? More importantly, what will be the natural response to an increase in CO2? Actually, the errors will compound. Given a climate sensitivity of 3 +/- 1.5 C/doubling, the uncertainy will increase as CO2 concentrations increase. Other forcings must also be included, although some will average out in the long term (i.e. ENSO).
84402. CBDunkerson at 00:18 AM on 1 June 2011
       Ljungqvist broke the hockey stick
       So what you are saying is that you didn't actually read the article. If you had you'd likely have seen the part about Ljungqvist conceding that current temperatures being higher than any other point in the last 2000 years. The reason that Ljungqvist's reconstruction doesn't show the "line flying off into blue sky" late in the 20th century is that... his reconstruction doesn't include the late 20th century. It stops before 1950. Figure 2 above shows the late 20th century warming from the instrumental record added on to the end of Ljungqvist's results in red.
84403. The Skeptical Chymist at 00:06 AM on 1 June 2011
       Database of peer-reviewed papers: classification problematics
       Some thoughts 1) It would be good to be able to suggest deletion of articles or movement of articles between categories. eg; checking the 2010 skeptic articles, I found that one is from Americanthinker "Climatism: Redoubling Misguided Efforts". Which doesn't belong in a list of peer-reviewed papers. eg: A paper listed in the 2010 skeptic articles is "Marine Reserves Enhance the Recovery of Corals on Caribbean Reefs", which is also listed under the myth "Corals are resilient to bleaching". Having had a quick look at the abstract and introduction it seems this paper is not skeptical about AWG or the threat of coral reef bleaching, but has identified a mechanism which can help reefs recovering faster from bleaching events. IMHO this paper belongs in the neutral section. 2) Naomi Oreskes' classification method is quite good in that it help to get a the guts of whether a paper accepts the basic consensus around climate changes, which is: are humans warming the planet? Perhaps papers could be classified by both methods? 3) Many papers are not shown to be wrong by specific rebuttal but simply become irrelevant over time. ie: a skeptic paper written in the 80's suggesting the climate was not warming or papers claiming the climate was not warming based upon the faulty UAH data. It would be useful if these could be marked in some way.
84404. Tom Curtis at 00:04 AM on 1 June 2011
       Database of peer-reviewed papers: classification problematics
       Eric the Red @5, in addition to CBDunkerson's well made points, I would add that the percentages you give are undefined because you provide no time period to your hypothetical. In the real world case, changes to CO2 forcing have a very small influence relative to ENSO on a year to year basis, but on a multidecadal basis they swamp the ENSO effects. So unless you specify whether you are considering annual, decadal, centenial, or (make your choice) variability, there can be no rational answer to your question.
84405. Tim Curtin at 00:03 AM on 1 June 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       In reply to skywatcher at 15:53 PM on 31 May, 2011 who said: "That's a large accusation to make without evidence there Tim Curtin, and yes you are cherry-picking, be it individual stations or individual records. The glaciers are 'cooked' as well, explains why nearly all of them are retreating". I do NOT cherry pick, Hansen and BoM do, that is why they prefer to use Wagga rather than Canberra, and Heathrow rather than Oxford. As for the glaciers, they have been receding since the end of the Little Ice Age, and thank goodness for that. A retreating glacier does NOT imply reduced rainfall, especially as ( -Snip- ).
       Moderator Response: (DB) All-caps usage is a Comments Policy violation; please refrain from their use.
84406. Tom Curtis at 23:46 PM on 31 May 2011
       Can we trust climate models?
       Eric the Red @70, the statistical test was for the accuracy at predicting the temperature for each given year given that you have initial conditions determined for that year by the model, and that you have known forcings. The test was carried out for over a century of time. Therefore, we can be confident that with known forcings, the models make accurate predictions. They make accurate predictions even a century out, given an accurate prediction of the forcings. Now of course we cannot accurately predict the forcings a century out. But that is a little irrelevant. It is irrelevant because the predicted dominant forcing under BAU is under our control. We can continue with BAU, in which case the GHG forcings will be high enough to completely dominate the normal range of natural variability and the temperature rise will be sufficiently large that the error in the models will be of no consequence relative to that rise. Or we can keep GHG forcings at or below current levels, in which case temperatures will rise by not so much that natural variability is inconsequential, or that the error is irrelevant. The Logic is very simple. Given forcings, the model makes accurate predictions. We can't predict forcings, but we can significantly control them. Therefore the models cannot tell us what will happen, but they can tell us what will happen if we continue at BAU. Finally, with regard to your specific point, the errors introduced from year to year in the retrodictions did not compound over the century and more of the model run. That was because the results were constrained by the forcings. Hence your point is irrelevant to my point.
84407. RyanStarr at 23:45 PM on 31 May 2011
       Ljungqvist broke the hockey stick
       Why no comments? This slaughters the hockey stick, without nitpicking the 20th century rise is on par with the MWP. And look at Mann's line flying off into blue sky late 20th century, Ljungqvist's does nothing of the sort. Originally Mann's HS didn't even recognize the MWP and him and others attempted to downplay it in other ways. A truely skeptical science site would hold that up as a discussion point.
84408. CBDunkerson at 23:27 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       Eric the Red wrote: "For instance, where would you classifiy a paper which concluded that global temperatures were influenced by the following factors in the given percentages? CO2:30%, solar: 25%, UHI: 20%, ENSO: 15:, albedo: 10%." Most likely classification: 'Fiction' If we are really talking about "global temperatures", rather than temperature anomalies, then the solar value is ridiculously low. If you meant to ask about anomalies then the solar, UHI, and ENSO values are ridiculously high. Obviously, it isn't really possible to classify such a hypothetical paper because we have no knowledge of the evidence shown for these conclusions. Based on known evidence they are beyond absurd, but the 'unknown evidence' of the hypothetical could be anything.
84409. Kevin C at 23:22 PM on 31 May 2011
       Can we trust climate models?
       Model accuracy and Cross Validation I've taken my empirical lag model a little further, and I'll show some results here. But at the same time I'd like to introduce a method which scientists and statisticians in many fields use to answer the question 'can we trust our model?'. The problem here is that you can make a model which gives an arbitrarily good fit to any set of data. How? Simply add more parameters. In the extreme case, you could just tell the model the answers, giving a perfect fit. But then your model only works for the data you already have. It's also possible to do this more subtly and fool yourself into thinking you have a meaningful model when you don't. So, in the case of calculating an empirical climate response function in order to get the temperatures from the forcings, we could simply assign a value for each year in a 120 year response function. If we refine those values to get the best fit against a 120 temperature series using 120 years of forcings, we can get a perfect fit: R2=1. But the result is meaningless. R2 is not a good indicator of model reliability. A simple approach is to prescribe a minimum data/parameter ratio. For example, if we want a data/parameter ratio of at least 10, then for a 120 year time series we can use no more than 12 parameters. But this approach is limited in a number of ways, for example a noisy datum is worth rather less than an exact value. So, how do we evaluate models? For one approach to this problem, we can go back to the scientific method. We start by forming some sort of hypothesis based on the information we have. There may be multiple competing hypotheses. These hypotheses are tested when we try and use them to predict the outcome of a new observation (in Popper's terminology, we subject the hypothesis to a test which is capable of falsifying the hypothesis). Or in other words, we test the predictive power of the hypothesis. So, in the case of a climate model, we could test the model by using it to predict climate for some period in the future, and then compare it with what actually happens. Unfortunately that takes a long time. Ideally we'd like something more immediate. This is where cross-validation comes in. The idea behind cross-validation is that we hide some of our data away - often referred to as a holdout or test set, and develop our model using the rest of the data. We then use the model to predict the values of the holdout set. The quality of the model is given by the match to the holdout set, sometimes referred to as the 'skill' of the model. We can do this multiple times with multiple holdout sets if required. We could, for example, hold out one year of data, and fit a model to the rest of the data. However, there is a problem: the year-on-year temperatures are highly correlated, as Charlie and others have noted. So the prediction doesn't require much skill. So let's go to the other extreme, and set the empirical lag model a very tough challenge. We've got 124 years of data. Let's hold out 62 years, and predict the other 62. We can hold out either the first or last 62 years (or any other set) - I'll do both. The correlations only run over a few years, so this is a real test of the model. Fitting the response function with only 62 years of data is a tough challenge, I had to make some improvements. Firstly, I produced an ENSO-removed temperature series by subtracting a weighted combination of the last 9 months of SOI data from the monthly temperature data, with the weights chosen to give the best fit between the temperature data and a 61-month moving average. Then I modified the model to use a response function constructed from 5 quadratic B splines, centered at integer positions 0,1,2,3,4 on a logarithmic time axis t' where t'=ln(t+1)/ln(2.5) (i.e. at t=0,2.5,6.3,15.6,39.1), constrained such that the spline coefficients must be positive. The b-spline is a bell curve like a Gaussian, but has compact support (i.e. no long tail to infinity which we can't fit against our limited dataset). The resulting model is very marginally better than the two-box model with both time constants refined (at the cost of an extra parameter), but much more stable. Unlike the two-box model, the parameters can be fit roughly against only 62 years of data (although an 80 year training set / 40 year test would be better). Here's the results of training 3 empirical models, with the models being trained against the whole time series, the first 62 years, and the last 62 years respectively. Clearly there is some sort of predictive power here - from the early period we can make a reasonable prediction of the late period climate, and vice-versa. How can we parameterise this? Here are the R2 statistics on the whole period and the two sub-periods for each of the three models:

       	R2 on 1880-2003	R2 on 1880-1941	R2 on 1942-2003
       Fit on 1880-2003	0.865	0.500	0.817
       Fit on 1880-1941	0.831	0.525	0.774
       Fit on 1942-2003	0.859	0.482	0.820

       The two numbers in bold are the holdout statistics. These are the real indicators of the predictive power of the model. Note that fitting a model on only part of the data improves the fit to the included data, at the cost of making the fit to the other period (the holdout set) worse. Throwing away data makes the model worse, and the holdout statistic tells us that. Note the numbers for the early period are systematically smaller because there is less signal in that period, not because the model is necessarily worse! The values here are not absolute - rather they can be used to compare different models. So at this point we could go back and do a real test of the two-box model (if it were stable) to see whether it is a better or worse model than the b-spline model, by doing the same calculation and looking at the holdout statistics. For completeness here are the response functions for the three models: We can see the benefit of compact support in the basis functions here: The response functions reach a plateau quickly for the short-period models, and have almost plateaued in the long run model. The climate sensitivities over the limited periods are 0.58 C/(W/m2) for the full-period model and 0.41 and 0.56 C/(W/m2) for the short period models. The lower number comes from fitting the early period, where there is less climate variation to fit the model parameters. These estimates should be considered lower bounds because the model explicitly excludes any long term response beyond about a century. Question To what extent do climate modellers make use of cross-validation in the evaluation of climate models? I don't know the answer to that question. Hence my queries at #16.
84410. les at 23:22 PM on 31 May 2011
       Can we trust climate models?
       70/71: sorry, re-reading, I misunderstood... scrub 71.
84411. kdkd at 23:04 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       I think the point is not so much the classification of the paper itself (as due to the way science is conducted most papers will be neutral), but the potential for the conclusions to be misused or taken out of context by deniers. Or by alarmists for that matter, but that seems a rarer occurance.
84412. les at 22:58 PM on 31 May 2011
       Can we trust climate models?
       70 - "Statiscally, when you multiple a value by ten, you multiple the uncertainty by ten also." you quite sure about that?
84413. Eric the Red at 22:52 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       I tend to dismiss these types of surveys as they are largely subjective. For instance, where would you classifiy a paper which concluded that global temperatures were influenced by the following factors in the given percentages? CO2:30%, solar: 25%, UHI: 20%, ENSO: 15:, albedo: 10%. (These numbers were completely made up and have no real bearing except to provide a basis for my hypothetical question.)
84414. Eric the Red at 22:46 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       AT, I think you are a little over the top there. I am glad you are so clear in your thinking. However, there are many of us in the field who understand that there are many things which we do not understand. The recent acknowledge by Hansen regarding aerosol forcings is one of them. To say there is no middle implies that there are two distinct "sides." Let us assume there is one "side" that says there has been and will not be warmer. My question is what is the other side? Is it 1C of warming? 2C? 4C? More? There exists today a wide range of model predictions and forecasts based on different inputs and forcings. Is the climate sensitivity 3C per doubling of CO2? Higher? Lower? Actually, 3C is just an average of several calculated values, with a rather wide range. It is neither black nor white, but very grey. I hope you were not referring to Doran's survey with your numbers, because that is woefully misleading, and could be classified as cherry-picked extraordinair. There are several credentialed scientists who would disagree with you or me on our positions, not that science proceeds by majority anyway. The logic statement is that an increase in CO2 will lead to an increase in temperature. If temperatures increase, we can make no inference about CO2. Conversely, if CO2 does not change, we can no make no temperature inference also. These so-called natural variabilites (and other man-made attrributes) must be removed from the logic equation in order to achieve the conditional statement. I believe this is the origin of the "muddled middle."
84415. Eric the Red at 22:20 PM on 31 May 2011
       Can we trust climate models?
       Tom, Your uncertainty is for one year, and cannot be applied uncorrected to a century worth of data. Statiscally, when you multiple a value by ten, you multiple the uncertainty by ten also. This is slightly different in that the uncertainties are compounded, and must be treated as such. In reality, the models that predict a 4C rise by the end of the century have a much higher uncertainty than 0.2. The actual uncertainties are an order of magnitude higher; different for different models. The models are accurate based on recent temperature measurements because they have calibrated based on past observations and been fined tuned to recent values. The models are being adjusted constantly, such that by the end of century, it is entirely possible, that the models will barely resemeble those today. We can make predictions based on current knowledge of forcings, but as Hansen pointed out recently, some of that knowledge has a rather high uncertainty. This will become irrelevant if those forcings change very little, but if they change appreciably, then the unctertainties could become huge. In summary, models cannot predict short-term changes accurately due to natural variability. In the long-term, we cannot say that the models are any more accurate, as seemingly small errors today could become large errors tomorrow.
       Moderator Response: [Dikran Marsupial] The uncertainty of a ten year trend is actually less than the uncertainty of a one year trend. The inter-annual variabilility does not apply multiplicatively to long term trends, but additively, and so the errors from year to year tend to average out to zero. That is why climatologists are interested in long term (e.g. 30 year) trends, not annual weather. Also asserting that the models are accurate because they have been fine tuned from recent observations doesn't make it true (reference required). If you look at Hansens 1988 projections, then they were actually remarkably good, and there can be no accusation of fine-tuning there (unless Hansen has a time machine).
84416. Bern at 22:12 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       Glenn, yes, I think you may have something there... I gave a (repeat) presentation at work today, about global warming. Depressing turnout - between two sessions, and only 10 people out of 40 came to see what it's about. That's in an environmental consultancy, too... My conclusion was a bad news / good news type thing. The Bad News: We're screwed. The Good News: We're not totally screwed. Yet. (speaking of which, I now have great admiration for people who can give a talk on global warming and keep the # of slides & the length down... I've got 75 slides in mine!)
84417. Ari Jokimäki at 21:42 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       Paul: "Local results can have a global context. eg. if it can occur in one location, then logically it may occur in another location due to AGW given the right circumstances." Yes, but remember that we are classifying only a single paper, we are not making statistics of several papers of different locations. For that single local paper, it is impossible to say anything about the global situation.
84418. Paul D at 20:50 PM on 31 May 2011
       An Interactive History of Climate Science
       Just found this NYT timeline which starts in the same year, although later it deviates from purely research papers: http://www.nytimes.com/interactive/2009/12/07/science/20091207_CLIMATE_TIMELINE.html However it has a similar groupings of events, with a greater density in modern times.
84419. Paul D at 20:12 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       Local results can have a global context. eg. if it can occur in one location, then logically it may occur in another location due to AGW given the right circumstances. Are there examples that can be discussed?? Would be interesting. Maybe the neutral circles in the visualisation should just drop to the floor in a pile, rather than cluster in a group :-)
84420. adelady at 20:03 PM on 31 May 2011
       An Interactive History of Climate Science
       Refutations. Might require a fair bit of faffing about. 1. Providing a link to a published paper which explicitly refutes the evidence/ conclusions after publication of the relevant item should be fairly straightforward. A little red dot, per paper rather than per refutation, in the relevant circle would be handy. 2. Some egregiously wrong papers which ignore or try to override others' well-accepted work could also have some indication (with a pale pink dot?) / link to a list of published works which contradicted the paper before it was ever written. 3. The thorny problem. Many truly dreadful papers are not refuted in formal papers by others after publication because the competent scientists just can't be bothered (again, and again, and again). But there are letters and similar critical responses where bad papers somehow made it into reputable journals. No idea how this might be incorporated.
84421. Glenn Tamblyn at 19:00 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       Wow, I am of the net for a day due to 'technology problems' and my post is already into specific stations and ice sheets! The purpose of this series is to look at the broader issues and 'encourage debate' and consideration of how to think about this subject, in the mathematical sense. I would like to make a general point. The concept of Teleconnection is well established in Climatology/Meteorology. Things are connected together. Damorbel has suggested that things such as elevation need to be considered. However this can easily fall into the trap of looking at temperatures rather than temperature anomalies. The graph from Hansen & Lebedeff 87 shown in post 1a (sorry but with the declining health of my laptop, posting a link is too hard). Is a plot of the correlation of Temperature Variation (Anomaly) vs station separation for station pairs. And it is based on randomly selecting those station pairs. Including variation in elevation. This is the key point, which can easily distract us. Long term climatic conditions at differing locations out to 1000 km or so ARE correlated, based on the evidence. Not that they have the same climate. But that their climates are related. Damorbel makes a valid observation that this will start to breakdown at the land/ocean interface. Even more so, we can't project this correlation out into the ocean. But these analyses only apply to land data. Ocean temps are processed separately. And this aligns with the observation I make that the correlation between stations and how they decline with separation is clearest in those latitudes with the highest proportion of land. However, Damorbel suggests that a 1200 km link is in some way unreasonable without supporting data. Firstly, the analysis from HL97 provides the supporting data. As I mention, commonality of weather systems passing over 'adjacent' locations provides a mechanism by which adjacent locations can see comparable temperature variations (anomalies). And from the data the 1200 km range is most reasonable at latitudes where there are high proportions of land. This is where the difference between temperature and temperature anomaly, climate vs climate variability can be a bit of a head bender. The mathematically valid approach doesn't align with our unconscious, intuitive sense. The unconscious is strong, but in this context it is strong. I will discuss some of these issues further in the last 2 parts of the series. But with the tight publication schedule here at SkS, that won't be till the end of the week.
84422. Paul Barry at 18:55 PM on 31 May 2011
       An Interactive History of Climate Science
       Well done. Nice presentation. Tor B's idea above to improve it is important. Some are likely to use the same graphic and say "Look! There is a substantial number of papers that argue against AGW. Hardly a consensus!" It would be very useful to be able to identify refuted and erroneous papers and even remove them from the graphic as well. This would also reflect the actual nature of scientific consensus: that it is not merely majoritarianism.
84423. adelady at 18:43 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       RSVP "...(If on the other hand, it seems there is more "evidence" in support of the effects of AGHG's, it is only because this line of thinking gets more airtime.)" I can assure you that a good paper with good evidence contradicting our current understanding would get a very, very good reception from at least this reader. There are a couple I'd be deeply, truly, really, really happy to see. The first one would be a demonstration that CO2 in the atmosphere behaves differently (and better for us) from CO2 in a laser. The knowledge that the warming we've seen so far is not necessarily indicative of what's to come would be fantastic. The other one would be a convincing then-and-now demonstration that the climate sensitivity shown by e.g. the escape from the 'snowball earth' state, is inapplicable in current circumstances because .... several valid reasons. Another occasion for rejoicing. (My longer list of unlikely demands includes a paper showing that a sea ice free Arctic can be maintained as a seasonal phenomenon rather than as a transient condition on the way to year-round ice free conditions. And a baker's dozen of others.) I'm pretty certain that many regulars here would give more, plenty more, 'airtime' to worthwhile papers giving quality evidence of this kind.
84424. Glenn Tamblyn at 18:09 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       John I have spent some time over the years discussing AGW on Unleashed. And I have never seen so many comments, so fast from so many DIFFERENT people. You really have dragged the lurkers out into the limelight. Do I get the sense that your somewhat more acerbic than usual tone has pressed a few peoples buttons. Quite a few people with tones of anger. It has been my experience of life that when you see anger, it is usually best to start looking for the fear that lives behind the anger. What fear could your post engender? The fear that the rather jerry-built edifice of 'Climate Denial Science' might be revealed for the house of cards that it is. And if the house falls down, well then they might have to deal with the reality that must be avoided at all costs. Confronting the reality that humanity is in D@@p S**t, and we have to do something about it. And treasured ideas of our sense of our place in the world may be one of the first and necessary casualties. This is the real denial. That their sense of how the world works, what is meaningful, may not actually match reality. And that they actually need to abandon that sense and replace it with one more grounded in reality. This is an existential burden that is hard on anyone. But there is one final arbiter of which 'view' of life is correct. Her view over-rules everyone else. Her name is Mother Nature. Her bat and ball, her back yard. So her rules. And if what we think doesn't match that, we loose. Thgis is hard for some people to handle, probably hard for their personality type to accept. The last vestiges of the Anthropocentric view of the Universe reside in the conservative, individualist personality type.
84425. Ari Jokimäki at 17:33 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       Caroza: "Isn't your definition of "neutral" going to artificially inflate the neutral bucket? A paper which is local in scope but which accepts AGW as causative or even axiomatic is not neutral in viewpoint, yet that is how it will be counted." As long as we are classifying these papers per argument, we need to do it like that. If the argument is global, then paper on one location is irrelevant for the argument, because local results can be remarkably different from global results.
84426. Ken Lambert at 17:28 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       DB at #99. KL: "Camburn has made several valid and reasonable points" DB: Which fail to stand up to scientific rigor and scrutiny. Well DB how about answering my #96, which goes back to your chart post at #58 and the issue of the validity or not of UCAR SLR chart. I see no scientific rigor in your posting conflicting chart evidence and then not explaining which is correct.
84427. caroza at 17:04 PM on 31 May 2011
       Database of peer-reviewed papers: classification problematics
       "I also think this same logic should be applied to research dealing with the effects of AGW on certain species: studies that focus on one plant species and how it will respond to AGW, for instance, are classified as “neutral” as well, as generalizations among plant species (especially) are illogical to make." Isn't your definition of "neutral" going to artificially inflate the neutral bucket? A paper which is local in scope but which accepts AGW as causative or even axiomatic is not neutral in viewpoint, yet that is how it will be counted. I think you're right that you probably need to extend the database to cater for classification per argument rather than only per paper, but perhaps you also need more classification dimensions.
84428. Bern at 16:58 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       philipm: oh, dear, not PDEs! (I really should have studied more during that subject at uni, it was the most interesting engineering maths subject I did. 20 years later, though, and I can barely even remember what a PDE looks like, let alone solve one!)
84429. Bern at 16:57 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       Hah, 326 comments and counting... looks like that analysis might take a while there, John! Certainly plenty of material, though... [rolls eyes]
84430. philipm at 16:44 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       The deniers are out in force at the Drum now. All repeating tired cliches. If there is indeed an argument against the mainstream science, I'm sure we would have heard it by now. Conspiracy theory is so passé. Science is supposed to be stuff like calculus. These people should get a grip and solve some PDEs, then report back on what they know about science. :(
84431. Bern at 16:43 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       RSVP: Kindly point out some 'evidence' against AGW, that has not already been debunked on this site. Those of us who support the science know there are uncertainties. We also know roughly how big they are, where they are, and what impact they have on the overall conclusion as to the existence of AGW (the phrase that comes to mind is "two thirds of stuff all"). Anyone with half a brain knows there is uncertainty. The only people who think the uncertainty is all on the low side (i.e. it all runs counter-AGW) *only* have half a brain... Is there a slim chance that some fluke of natural climate variability just happens to have produced a warming signature that exactly matches that of increased GHGs, right at the time when humans are emitting billions of tons of the stuff? Yes, there is. Is there a slim chance that you can jump out of plane kilometres above the ground without a parachute, and survive? Yes, there is. It's probably not a good idea to try it, though. The odds are somewhat against you.
84432. Tsumetai at 16:19 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       

       What Hansen is doing is looking to see if he can reconstruct temperature records where there aren't any which is creative, not scientific.

       And yet this 'creative, not scientific' approach produces basically the same results as everything else. Apparently, Hansen is some sort of wizard.
84433. jacob l at 16:06 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       it is worth noting that N.C.D.C. uses Empirical Orthogonal Teleconnections to fill in areas that are not well represented,so it's not just an average of stations in a 5 by 5 grid cell, I don't mean to take way from any other points being made thanks jacob l
84434. tallbloke at 15:55 PM on 31 May 2011
       Climate Change Denial book now available!
       skywatcher@71 "It's rather hard to have ice ages with low sensitivity." In Defense of Milankovitch Gerard Roe GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L24703, doi:10.1029/2006GL027817, 200 Received 9 August 2006; accepted 3 November 2006; published 21 December 2006 http://courses.washington.edu/pcc589/2009/readings/Roe.pdf
84435. RSVP at 15:54 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       "Deniers, on the other hand, refuse to accept any evidence that conflicts with their pre-determined views." ...as is the case of AGW GHG supporters. These however, deny their denial, making for "denial squared". (If on the other hand, it seems there is more "evidence" in support of the effects of AGHG's, it is only because this line of thinking gets more airtime.)
84436. skywatcher at 15:53 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       That's a large accusation to make without evidence there Tim Curtain, and yes you are cherry-picking, be it individual stations or individual records. The glaciers are 'cooked' as well, explains why nearly all of them are retreating...
84437. owl905 at 15:42 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       Deniers and skeptics is way too ivory tower ... or ivory soap. They're pro-pollutionists. (Hint: try the phrase out, and count to ten, then count the number of 'CO2 isn't pollution' responses). The mindset was bottom-lined on alt.globalwarming almost 15 years ago: "The notion that Man can have any effect on the climate is hubris." They truly believe that there are petty consequences to inaction; versus higher taxes/wrecked economies/3rd transfer plots/world government conspiracies ... reducing the pollution. The basic issue at street level, unfortunately, is intelligence. Some of the banal comments here illustrate that: restart and redefine the terms; invent a fictitious expectation and then claim valid skepticism when it isn't found; warn people that discussing those terms could polarize the discussion; develop a CO2-thermostat that will turn down CO2 emissions, and atmospheric levels will fall; somehow make the Greenhouse Effect 'go away' or stop working. It's turned into a Clown Convention for the Anti-Science Society. It's the reason crypto-science like WUWT out-vote realclimate as best science blog.. Skeptical Science does a great job of getting the science out to the non-science world. Unfortunately, it comes up short of being a decent bug-lamp.
84438. Tim Curtin at 15:39 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       Tom: so why does GISS have 2 different figures for Canberra, depending on the 250 or 1200 km radius? If Wagga is good enough for one (and I have been to the met.station there)why is it not good enough for the other? Your data confirm that Wagga is more convenient than Canberra. Canberra does have a number of met.sites. I prefer real data to the confections of Gistemp.
84439. scaddenp at 14:56 PM on 31 May 2011
       Climate's changed before
       Just to add to comments on CO2 measurement, you might like to look at this on measurement of CO2 in general and problems with the old chemical measurement. Further Keeling, responded to Beck's stuff with this comment. "It should be added that Beck's analysis also runs afoul of a basic accounting problem. Beck's 11-year averages show large swings, including an increase from 310 to 420 ppm between 1920 and 1945 (Beck's Figure 11). To drive an increase of this magnitude globally requires the release of 233 billion metric tons of C to the atmosphere. The amount is equivalent to more than a third of all the carbon contained in land plants globally. Other CO2 swings noted by Beck require similarly large releases or uptakes. To make a credible case, Beck would have needed to offer evidence for losses or gains of carbon of this magnitude from somewhere. He offered none. " Are you sure that measurements you refer to dont run foul of same issue? (mass balance).
84440. Albatross at 14:49 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       Moderators, Please snip all text written by on this thread me that has violated the house rules. I do not want any claims of favoritism being made, nor do I expect any favoritism. The body of science stands on its own anyways. The cherry-picking of statistically meaningless and insignificant windows continues @102..... Please also delete this message if you wish.
       Response:

       [DB] The issues in play have been discussed and dealt with.

84441. scaddenp at 14:43 PM on 31 May 2011
       Climate's changed before
       1/ I agree TOA energy imbalance includes all sources of energy, but there is no way to infer from OLR that there natural warming going on. In contrast, the spectral signature of OLR matches the expected spectra for OLR. An increase in OLR W/m2 just tells you planet is warming. By itself this tells you nothing. Energy balance is difference with energy in and that is what we expect. This is a very confusing argument. 2/ Look at the whole list of proxies available in WG1 report, with and without tree proxies. The different published proxies vary in detail but support a consistent picture. We are getting hotter. 3/ Please provide a reference to these. The usual source of this argument is EG Beck's collection of old references. Got a better reference. All proxies have problem, ice data just happen to be among the best. What's your reference for problems with ice bubble data that you think allows for a different interpretation?
84442. Tom Curtis at 14:36 PM on 31 May 2011
       Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
       Tim Curtin @23, the highest High Quality network station to Canberra is Wagga Wagga. If GISS just used the nearest station, that is the temperature record they would use. As it happens, GISS shows a 1910 to 2010 trend of between 0.2 and 0.5 degrees C per century in South Eastern NSW (including Wagga and Canberra). In contrast, BOM shows a 0.9 degree warming trend over the same period at Wagga Wagga. I checked the Canberra location only because you brought it into discussion. Clearly your concerns about GISS artificially inflating its temperature trends are unwarranted, a fact we already knew from the similarity between GISS trends and other major surface temperature indices.
84443. Camburn at 14:36 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       Albatross: When I am discussing an issue I prefer not to ruffle feathers, so I shall not post to this thread in the future. I have pointed out that sea level rise has slowed. Why does that upset you so much? I have pointed out that according to ARGO data, 0-700M OHC is static since 2003. When you go to woodfortrees.org and plot hadcrut ocean anomlies from 2005 thru 2011, the trend is also flat. These are observations that are recent. To me they indicate a change in trend as three very large metrics concerning heat show a flat trajectory. You also seem to have a problem with Houston and Dean's paper. Tell me what the problem is with it please. It is actually a quit wide ranging paper, talks, with references, about the current problems in determining the rate of SLR. I wish you well. The counter arguement, if you think it is an arguement, is not weak, as it is supported by empirical data and the link you so graciously provided that I quoted, in ref to the data that is currently present.
       Response:

       [DB] "I have pointed out that sea level rise has slowed.  Why does that upset you so much?
       
       I have pointed out that according to ARGO data, 0-700M OHC is static since 2003.
       
       When you go to woodfortrees.org and plot hadcrut ocean anomlies from 2005 thru 2011, the trend is also flat."

       Several problems here, chief of which is the focus on statistically insignificant timescales (which is also called cherry-picking).  This issue has been pointed out to you in the past.  For a recent discussion of the issues with that practice, see here and here.  Also, 0-700m is not the whole ocean.  Various other studies show heat being transported deeper than that.

       Sea Level Rise:

       

       OHC:

       

       "You also seem to have a problem with Houston and Dean's paper."

       Many others do as well.  Commentary by Church and White begins here.  Longer analysis found here (which you were given previously).

84444. Ari Jokimäki at 14:35 PM on 31 May 2011
       An Interactive History of Climate Science
       Perhaps the refuted paper should travel to "refuted" bin after the year the refutation has been published?
84445. Albatross at 14:19 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       Ken @99, So you too endorse quote mining, cherry-picking and misrepresenting scientists' findings and position on certain issues then? As I and others have demonstrated that is what a certain poster has been doing. And now you seem to be endorsing that behavior... Tamino perfectly described what Camburn, and now you it seems, are up to. Camburn states that according to ARGO data global SSTs are "presently static". Presently? Framing the argument that way is disingenuous, we all know that cherry-picking short-term, statistically insignificant windows is meaningless. You seem to be claiming that to do so is a valid and reasonable point? Camburn ignoring the data presented to him here by me and others is reasonable? Him uncritically accepting Houston and Dean's troubled paper is reasonable? You guys are desperately trying to advance a very weak counter argument here, and it is showing. Now good night.
84446. Albatross at 14:10 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       Daniel, To add to your Figure above @98. Long-term SST, statistically significant trends are very much UP. [Source]
       Response:

       [DB] Thank you.

84447. Ken Lambert at 14:09 PM on 31 May 2011
       The Critical Decade - Part 1: The Science
       DB at #98 DB is confusing us at #98. viz: "ARGO says otherwise' - then reproducing Fig 1 of Levitus 2009. Only the 2003 and later portions of the chart are from ARGO. Reason: Full deployment did not start until the 2001-03 period. The step jump in this chart in that 2001-03 period has been discussed elsewhere - and is more likely an artifact of the splicing of Argo to pre-2001 XBT and other methods. Camburn has made several valid and reasonable points to be called 'recalcitrant, deluded, disingenuous' by Albatros. Why is Albatros immune from moderation?
       Response:

       [DB] "DB is confusing us at #98."

       "Us"?

       "viz: "ARGO says otherwise' - then reproducing Fig 1 of Levitus 2009."

       If you had clicked on the image itself or had followed the source link you could have easily noted that the graphic in question is hosted by the ARGO website and is used by them to display the very same information as related here.

       "Camburn has made several valid and reasonable points"

       Which fail to stand up to scientific rigor and scrutiny.

84448. PhillyWilly at 14:04 PM on 31 May 2011
       Climate's changed before
       1 Yes Partially correct..Its indeed part of the TOA imbalance, but the TOA imbalance includes more than just the CO2 spectrum. NOAA/CPC both show increasing avg outgoing LW radiation...indicating that there is natural warming going on as well: http://www.esrl.noaa.gov/psd/data/gridded/data.interp_OLR.html Note the Increase is by several W/m^2, in fact it has increased by about 3W/m^2 since 2002, and since 1980 there has been an overall increase. That is not only indicative of nautral warming from the planet (not caused by CO2), but also a negative feedback since 3W/m^2 is more than the 1.6W/m^2 cited by the IPCC since 1790, which should supposedly due to positive feebacks have amplified to the 0.8C we've increase we've seen, since per Doubling the increase in temps is progged around 1.2C. The changes in CO2 energy increase has been significantly less than the obsevred OLR change in the time we've measured, and we've likely mis-represented the feedbacks to CO2 warming. 2) No they don't actually, although it depends on the tree-rings used. Ice core proxies show the polar temperature to have been warmer by 2C at time in the past...so if Tree ring proxies show the same thing...why are the similarities invivible??? 3) What makes you think these CO2 measurements were taken only in "polluted cities"? And no not referring to "beck", but more of the measurements in geenral. Do you know what happens to data trapped in Ice Cores over time? take a guess :-)
84449. trunkmonkey at 14:02 PM on 31 May 2011
       CO2 only causes 35% of global warming
       Dikran Marsupial @3. I did read the link you provided and did some further research. It was a real eye opener to understand how the greenhouse effect works in a gas. It's not like your car or a greenhouse. That is why I went so far as to suggest a possible mechanism for CO2 control knob function as a lid in the stratosphere. (I've often wondered why thunder clouds anvil off so sharply when they hit the bottom of the stratosphere. Sure, they are on a moist adiabadic path and the stratosphere is very dry, but there is no dry adiabadic inversion there) How do you know the oceans are a carbon sink and not a source? Because they are acidifying? What if the acidification came from subsurface CO2 via metnane?
       Moderator Response: [Dikran Marsupial] Had you read the RC article, you would not have written "In the parts of the absorbtion spectra where CO2 and water vapor overlap water vapor seems to dominate the absorbtion and reduce the effect of CO2." as the article explicitly says that this is not the case (I even gave the relevant quote in my reply on the other thread, and put it in bold so you must have seen it). As for knowledge regarding the oceans being a carbon sink, see the work of Corinne Le Quere (for example). As to carbon being the "control knob", it is actually more like a thermostat (it only becomes a control knob if the natural feedback mechanisms are over-ridden by e.g. fossil fuel emissions), see the book by David Archer reviewed here.
84450. Composer99 at 13:55 PM on 31 May 2011
       Are you a genuine skeptic or a climate denier?
       I feel somewhat vindicated in the comment I left on the ABC Drum site noting that there was a dearth of reference to supporting evidence on the part of the commenters who took offence to being characterized as deniers, as that behaviour appears to have remained characteristic (with very rare exceptions) on the comment thread.

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