Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1279  1280  1281  1282  1283  1284  1285  1286  1287  1288  1289  1290  1291  1292  1293  1294  Next

Comments 64301 to 64350:

  1. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Point for those looking at the benefits of a Kindle version - I've made extensive 'highlights' clippings in the book, and they've all uploaded to my account at Amazon [Kindle] ready to be cut and pasted. I can also make notes, if I can bother with the fiddly keyboard (better than a phone, though!) Oh, and it's $9.99 and downloaded before I could check to see how fast it was downloading! I'll finish the ad now... Incidentally, this review came up #1 in a google search for 'mike mann hockey stick climate wars'. I realise google tailors its searches, but there's some hope this might act as a counterweight to all the 1 star review shenanigans, and, importantly, spread awareness of this Denialist tactic.
  2. Global Sea Level Rise: Pothole To Speed Bump?
    Steve Case, the current ice contribution to total sea level is relatively small, and so you won't see a geometric curve in the total SLR, such as the 20-year figures shown above, as it is hidden by other components. Accelerations in ice mass loss (such as observed, e.g. Veliconga et al 2009) will come to dominate the SLR budget if the accelerations in mass loss of the ice sheets continue. As it is, the SLR curve for the whole 20th Century shows acceleration too, not visible on a 20-year plot. Quite how fast the acceleration continues, once ice loss comes to dominate, is the matter of question, not whether the acceleration has started. David Stoney, thanks for the links. Always worth listening to what Bindschadler has to say about Antarctica, the first link is particularly informative.
  3. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Camburn #45: You really need to read the Quantifying Extreme Heat Events post, and comment on that post why you think it does not show an increase in extremes.
  4. The real doping scandal: Weather on steroids
    Would be better if the analogy was cricket, although the video would be a couple of days long :)
  5. CO2 lags temperature
    jzk - forcing from GHG = X; forcing from solar = Y; forcing from albedo = Z Temperature is function of X+Y+Z. If X stays same, and Y goes down, then temperature must drop. Now there is a lag, X will rise slightly while Y goes down, but once Y goes lower than X, the cooling starts and the negative feedbacks kick in to reduce first albedo, then water vapour and then CO2. It is worth noting though that the nature of milankovich cycle is that first change when cycle goes negative will be to albedo, as the effect is primarily on NH mid-high latitudes (where is forcing change is quite large compared to both GHG and global solar change).
  6. apiratelooksat50 at 07:10 AM on 10 February 2012
    Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Sphaerica at 37 I don't even know to say about your chauvinistic-militaristic comment. That's quite a stretch, even for you, and totally unfounded. If you noticed from my post I am first on the list at my local library when they receive the book, and I intend to read it.
  7. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Dorlomin (34) wrote: “I for one am disappointed the spoilers are getting removed.” I was too at first, but the only one I have noticed disappear is the “t**d” one, and when I checked that commenter’s past reviews it is clear that at least once in the past he had posted a poe.
  8. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    re: Camburn @45 Yet another "sounds like" like argument. It's one thing for Rush Limbaugh to spout a "sounds like" argument to an audience who don't demand better, but why make one here? And it's rather ironic to make a "sound like" argument in response to my question about what denialists's end game might be. I take it that there isn't any. Ah, Dives we hardly knew ye.
  9. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Camburn, It is only the frequency of extreme events that is something recent. Please cite a past year wehre they had anywhere near the amount of extreme weather that the globe has had in both of the past two years. 2012 is starting out with more of the same extreme weather. A major cause of the dust storms in the 1930's was poor farming practice. This was not the case last year in the Texas drought. You provide a perfect example of a denier who will never look at the data.
    Response:

    [DB] Please take the discussion of extreme weather to a more appropriate thread.

  10. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Camburn: Jeffrey Davis' comment was "increases in droughts, floods, and violent weather" [emphasis mine]. Given papers such as, if memory serves, one by Hansen, examined on this site this is an entirely reasonable statement. Does Jeffrey's wording actually strike you as the wording someone who was ignorant of past weather extremes would use?
  11. Global Sea Level Rise: Pothole To Speed Bump?
    Thanks for an informative post and many useful comments. For what it may be worth, the term "collapse" should probably be approached with caution. Living near the southeast US coast and being uncertain about what the term might mean with regards to WAIS, I asked Robert Binschadler to help me out. He allowed that a "collapse" of WAIS might give rise to a 2 m/century SLR. Here's an interview with Binschadler Here's what's happened more recently at Pine Island Glacier Not comforting...
  12. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Jeffrey Davis@41: To remind you that weather extremes are not something recent, I can only advise you to study the dust storms in the US during the 1934-1936 period. America: The Story of US Narrated by Liev Schreiber has very good video of that time period. This is one example of extreme weather. Another would be the Mississippi Flood of 1927. Mississippi Flood of 1927 Extremes are not a recent event.
    Response:

    [DB] Please take discussions of extreme weather to a more appropriate thread.

  13. The real doping scandal: Weather on steroids
    Yes, good analogy and a funny video. Nicely done.
  14. The real doping scandal: Weather on steroids
    I like this. Pretty good actually.
  15. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    For a good laugh, click and read all of the "see all my reviews" buttons on amazon for ANY of the 1 star ratings of Mann's book... Some have no other reviews, and others are giving 5 stars to denier books, and frequently using language like "libtards" in their reviews... wow.
  16. Global Sea Level Rise: Pothole To Speed Bump?
    #63 Sascha @ 02:28 As Skywatcher says, I think the rate of sea level rise increasing more than 100 times the current value is incredible, "argument from incredulity" he says. I like to go to the source of these sorts of claims and run the numbers. I'm always in fear of getting the sign wrong or getting decimal places wrong or going off half-cocked. Somewhere up thread it was pointed out that Dr. Hansen's curve isn't an asymptote but sigmoid or geometric. They were right. Eventually it has to level off. I can't go on forever. Considering that the geometric nature of that curve hasn't started yet, see my post #2 on this thread; I wonder when it will start. I would think anyone would.
  17. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Jeffrey, I've long wondered what the end game for climate denial is. There isn't one. A few people will cling to vocal denialism no matter what, but most will simply change the subject and move on to the next ideological battleground. And unless the media change greatly, it'll be considered impolite to question their judgment. As long as you're wrong for the right reasons, no apology is necessary. Anyone who's capable of shame would've felt it by now, in my opinion.
  18. CO2 lags temperature
    jzk, for a scientific article on the ice age cycle I'd suggest Shackleton 2000.
  19. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    re: 41 Sorry. Abraham was speaking to Dives there.
  20. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I've long wondered what the end game for climate denial is. The increases in droughts, floods, and violent weather over the last few years are due to a modest .8C of warming. 2.5C? The mind reels. I'm constantly reminded of the line from the parable of Lazarus and the rich man in Luke: Abraham said to Lazarus 'If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead.'
  21. Global Sea Level Rise: Pothole To Speed Bump?
    @ Steve Case #62 I am always interested in "contrarian" opinions ... they sometimes offer a glimpse of hope in - what I consider - a bleak picture. Do you not agree with the figures or with the conclusion? Would you be kind enough to tell me why or refer me to something to read which reflects your view?
  22. CO2 lags temperature
    jzk wrote: "Of course as temperature lowers, CO2 is absorbed, and that contributes to cooling. But first it must start its descent despite the presence of these warming gasses." Think about the actual physical factors involved. The Milankovitch forcing is due to orbital tilt. Why/how would GHG have any impact on when the 'sign' of that forcing changed? Yes, "it must start its descent despite the presence of these warming gases"... but there is absolutely no reason that it wouldn't do exactly that. That is, the change in atmospheric composition is obviously not going to change the orbit. You then agree that once the cooling from the orbital shift kicks in "CO2 is absorbed, and that contributes to cooling". So what exactly are you arguing for... in terms of a physical process? You seem to be stuck on some sort of idea that, 'because GHG make it warm, it cannot cool until the GHG are gone'... which is incorrect. The Milankovitch change in orbital forcing is not in any way restrained by the presence of GHGs. It switches to cooling as the orbit of the planet shifts. That cooling lowers the temperature of the oceans and allows them to absorb more CO2... which causes more cooling.
  23. CO2 lags temperature
    jzk - Feedbacks act as a scaling on whatever forcing changes occur, which is why they are feedbacks. At the peak of an interglacial the climate is in (relative) equilibrium, no thermal inertial to wait for, the climate is not changing (important point). Then the Milankovitch forcing changes downward. If there were no feedbacks whatsoever, such a change in energy will of course cause the climate to cool. With feedbacks (water vapor, CO2 after 500-800 years, albedo changes, etc.) the climate will cool to a larger (positive feedbacks) or smaller (negative feedbacks) extent than the direct forcing change alone would cause. Feedbacks are a response to forcing, not an independent entity. If forcing changes, the feedbacks will as well - they will not (independently) hold the climate energy stationary, or they would instead be independent forcings. Over geological time frames feedbacks are very fast - amplifiers of forcing changes. If you are speaking into a microphone, and drop your voice to a whisper, would you really expect the amplifier to keep the output volume unchanged? Or would you instead expect the output volume to change as per your input volume change times the amplification?
  24. CO2 lags temperature
    CB @336, I don't refer to the "accumulated warming" or "inertia" of the temperature rise. However, all of those gasses that are present at peak temperature contribute to warming just by being there. It is not as if they are a "fuel" that burns out, they warm by trapping radiation. Does not that warming need be overcome by the downward Milankovitch forcing in order for other positive cooling feedbacks to kick in? Of course as temperature lowers, CO2 is absorbed, and that contributes to cooling. But first it must start its descent despite the presence of these warming gasses. Again, thanks for helping me with this, any citation to the peer reviewed studies would be much appreciated.
  25. Global Sea Level Rise: Pothole To Speed Bump?
    #60 KR at 16:09 Yes, I read you post.
  26. CO2 lags temperature
    jzk wrote: "However, before that can happen, the cooling effect to prevent the melt via the top end Milankovitch factors must overcome the very powerful warming effect that the high level of CO2 has." No, this is an inaccurate view of the situation. Cooling from the 'negative Milankovitch forcing' does not have to 'overcome' the total accumulated warming from the 'positive Milankovitch forcing' and all feedbacks before cooling sets in. The transition is 'immediate' save for a very short (geologically) lag time. Once the Milankovitch forcing passes the 'warming peak' there is then progressively less of a warming forcing, which results in progressively less atmospheric water vapor (and thus lower water vapor feedback), more ice formation, oceans cool and absorb more CO2, et cetera. There is no (long term) 'inertia' to overcome... when the sign of the forcing changes all the feedbacks do as well.
  27. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    If you want to see Mike Mann working as a scientist drop over to this thread on Real Climate Volanos, Trees, Bark Especially note the exchanges in the comments. The contrast to WUWT couldn't be clearer.
  28. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Read the book? That's too much to expect. Some folks don't even want Mann to be able to speak in public at his own university. Coal group raps Mann, seeks halt to lecture These groups attract the same people who scream about their 'liberty' and fear their 'freedom' will be taken away.
  29. CO2 lags temperature
    jzk @333, the short answer is that after the passing of the peak Milankovitch NH Summer warming, the Earth cools very slowly over several thousand years. Because cooler water absorbs more CO2 than warm water, that cooling gradually reduces the CO2 level in the atmosphere. Studies have shown that a Milankovitch Minimum NH summer warming will initiate a new glacial only if CO2 levels are at around 240 ppmv (+/- 40 ppmv). The large range is due to the fact that there are a range of studies giving partly overlaping results in that interval, and also because the level of CO2 that will stop the initiation of a glaciation depends critically on the strength of the Milankovitch Cycle. Historically, at least on glacial commenced when CO2 levels where at around 280 ppmv, but most initiate with levels around 240 ppmv, and Berger and Loutre show that even in a weak cycle, glaciation will initiate with CO2 levels around 210 ppmv.
  30. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I like Manns work and the thousands like him that contribute to our knowledge about AGW. But I don't have the attention span these days to read peoples 'life' stories. I did start reading it (like I started reading Hansens book) but got bored. I wish these scientists would spend time to write popular science books or work on TV documentaries that get the science across to millions of people, instead of this sort of thing. That would be far more productive than these types of books.
  31. Medieval Warm Period was warmer
    Tom @73, I have no problem drawing that conclusion from the Mann data, and of course I have noticed that. That is the kind of presentation that SkS should have. But picking a decade of our recent warmest data (+- 3 years) and comparing it to 300 years of previous data just so that one chart will be full of white and the other red does nothing other than to mislead people that don't actually look to see what is behind the chart. I use the word "mislead" as a description of the effect of the comparison, not the intent. I have no idea what the intent was. If the data are on your side of the initial premise anyway, why not just present it in the most fair way possible?
  32. Dikran Marsupial at 23:58 PM on 9 February 2012
    CO2 lags temperature
    jzk The change in CO2 between glacial and interglacial conditions is only from 190 to 270 ppm, an as the fadiative forcing from CO2 only increases logarithmically it isn't necessarily "very strong" compared to the change in solar forcing due to Milankovic cycles. You would need to compute the numnbers to know whether your argument was valid, and I strongly suspect that the scientists did that before publishing their finings. Also the feedback from CO2 is self limiting in the sense that IIRC the outgassing of CO2 due to heating of the oceans is linear, so in the absence of external forcings it would rapidly (on geological timescales) reach a new equilibrium. Thus by the time Milankovic cyle went into a cooling phase CO2 would no longer be on the way up.
  33. CO2 lags temperature
    I am very interested in understanding how the Milankovich cycle at the top of the cycle reverses warming when the influence of CO2 is so strong and continuing to experience positive feedback (although perhaps diminishing). I understand that "Northern ice sheets melt less during summer and gradually grow over thousands of years. This increases the Earth's albedo which amplifies the cooling, spreading the ice sheets farther." However, before that can happen, the cooling effect to prevent the melt via the top end Milankovitch factors must overcome the very powerful warming effect that the high level of CO2 has. At this point, of course, CO2 is still rising and ought to be more powerful than any other time during the cycle. The Imbrie, et all papers don't deal with this that I can see. I realize that this issue isn't novel having been discussed on this forum before, but what peer reviewed authority engages this issue? Thanks!!!
  34. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Pirate and Dale, Your Wattsian views of the issue as a debate with sides, recruitment, demarcation lines, and most importantly "belief" all point to a perspective that this is all about personal choice. On the one hand, I'd tell either of you that your time would be much better spent reading something else that teaches you about the actual science. On the other had, given your rather chauvinistic-militaristic view of the issues, perhaps what you need is a better insight into the perspective of someone other than yourselves (like that of a scientist who is doing his job, coming up with data and analyses that other people don't like, and then being hounded and vilified for it). You two are exactly the sort of people who should read the book, but with an open mind and an eye towards learning something about how your fellow skeptics behave and the use of "tactics" as an approach to a field of science, rather than participation in the science itself.
  35. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    31, Bernard J. That's not at all a bad idea, and one that would be easily enforced. At a minimum, there should be a big icon next to a commenter's name showing who has or has not bought the book from Amazon. Comments should also be sorted in that order (people who bought it first, people who claim/pretend to have bought it second), and summarized that way ("Average rating for the people who bought the book from Amazon, 4.89, Average rating for all others, 1.32").
  36. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    What is particularly interesting, in a behavioral way, is the swarming of the Amazon site. I'm still reading Mann's book, but the goings-on with all those negative reviews from people who must somehow be able to read dozens of pages a second (!!!) provide an absolutely classic example of the politics of the climate debate. Mann writes an account of it and a whole bunch of helpful dudes then come along to provide of working demonstration of what he describes!
  37. Dikran Marsupial at 22:29 PM on 9 February 2012
    Still Going Down the Up Escalator
    RobertS (various posts) "Slope in a linear regression of either temperatures or GCM output, however, is still an unobservable parameter - it's not a measurable, identifiable feature of the data itself, but of your particular model - and cannot be verified" This is not true, as others have pointed out there the data has a unique linear least-squares fit, just as the difference between the temperature at the start point and end point is uniquely defined by the data (as I pointed out on Dr Brigg's blog). You can view linear regression as being a generative model of the data, however it also has a perfectly reasonable interpretation as a descriptive statistic. "but I believe Briggs overall point is that the frequentist interpretation of confidence intervals is not intuitive, which begets confusion." This is true, conidence intervals are counter-intuitive, however if that is Brigg's overall point he is making it rather indirectly, to say the least! "And that confidence/credible intervals of observables is preferable to confidence intervals of model parameters." This is non-sense, which is preferable depends on the purpose of the analysis. "I don't have a problem with a global mean surface temperature. The issue comes with how uncertainty in this value is calculated and viewed, and how a change in GMST is determined." Are your concerns answered then, by my analysis which shows that using Bayesian methods, the uncertainty in the estimates of GSMST have almost no effect on either the expected regression or the credible interval? You might want to ask yourself why Briggs hasn't already performed this analysis before making a fuss about it on his blog. BTW, not all statistics should be "predictive", they should be chosen to suit the purpose of the analysis. If you are aiming to predict something, then obviously predictive statistics are likely to be most appropriate. If the purpose is to describe the data, then descriptive statistics are appropriate, if you are exploring the data, then exploratory statistics. Ideally a statistician should have all of these tools in his/her toolbox and be able to chose the appropriate tool for the job at hand.
  38. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I for one am dissapointed the spoilers are getting removed. Perhaps someone can get in touch with Mann and see if he can get Amazon to keep them up. They are pretty much evidence of the books argument.
  39. Dikran Marsupial at 22:09 PM on 9 February 2012
    Still Going Down the Up Escalator
    Steve L The Bayesian analysis doesn't take autocorellation into acount (unlike Tamino I am no expert in time-series analysis - yet ;o). However the main aim was to determine whether the effect of the uncertainty of the estimates of GMST had much of an effect on the width of the credible interval. It doesn't which suggests that Dr Briggs is making a bit of a mountain out of a molehill (if not a worm cast), in my opinion. BTW, if you are interested in Bayesian statistics then a good place to start is Jim Alberts book "Bayesian Computation with R", which as a package for the R programming environment called "LearnBayes" that implements Bayesian linear regression (which I used to generate the plots).
  40. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I've just checked and can report that Amazon appears to have removed the short, 1-star, deliberate 'spoilers'. Actually the reviews now left seem to illustrate well the polarity of the discussion and, if anything, will encourage the casual viewer to read the book. So shall we call this 'bookgate'?
  41. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    Other than Craig Loehle, none of those opposed to Mann have done their own reconstructions. This one of the salient points, they dont have a credible alternative to offer.
  42. Global Sea Level Rise: Pothole To Speed Bump?
    Skywatcher/KR Understood ... collaps means exactly that. Nothing gently timeconsumig about it. (I got waylaid by language, like: economic collapse) Thank you for clearinng the head. It isn't a story easily told to Monckton enthousiasts though (there are still a few left).
  43. Volcanic Influence on the Little Ice Age
    @Klaus 20 - Scaddenp quotes the best reconstruction. Add to that a Swedish study that highlights the disjoint between past northern and southern hemisphere trends. http://www.physorg.com/news/2011-10-simultaneous-northern-southern-hemispheres-result.html It's noteworthy for the current warming that the effect is ubiquitous. That's very different from the reconstructions that show both regional and hemisphere differences driven by natural variations.
  44. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    The denialist carpet bombing shows a serious flaw in Amaon's comment system. It is being hijacked for political purposes - something about which the Amazon management should be excedingly concerned. Frankly, reviews for topical material books such as this one is should only be accepted from people who have purchased it from Amazon. Similarly, comments should only be accepted from folk who have a minimum purchase history with Amazon. It's not only in Amazon's interests as an ethical trader, but as a successful one, that they weed out politically-motivated nonsense.
  45. Still Going Down the Up Escalator
    RobertS, the data of the temperature series is a set of pairs of numbers. The linear regression of such a set has a unique solution. Therefore it is a property of that set of numbers. So, to answer the question, it is a property of the data set, not of our mathematical manipulation. We could employ the same form of verbal tricks you do in making your case with regard to measurements. Consider a simple mercury thermometer placed in a pot of water. The length of the mercury column in the evacuated tube depends critically on the diameter of that tube. Does that make the temperature a property of the evacuated tube, of the the manipulation of glass in creating the tube? By your logic we must conclude it is a property of the glass blowers manipulation. Perhaps that is to simple for you. Suppose instead of a mercury thermometer we measure temperature with an IR thermometer. The IR thermometer records the intensity of IR radiation across a range of frequencies. Using the laws of black body radiation, a computer chip then calculates the temperature of the body emitting the radiation. So, is the temperature a property of the pot of water, or the mathematical manipulation that derived the temperature from the IR radiation. For consistency, you need to say the later. But then you are committed to the claim that Planck's law has a temperature of x degrees, where x is the result of the measurement. Going back to your example, the formula for the linear regression of a time series does not have a slope of 0.175 C/decade (+/- 0.012°C/decade). Neither does the computer, or the pages of paper on which the calculation was performed. That slope is the property of the NCDC temperature data. In other words, it is simply incoherent to say the linear regression is a property of the mathematical manipulation rather than the data. It is absurd on the same level as saying "The green dreams slept furiously together". And the reason you are generating such incoherent notions is because you are trying to reify a purely pragmatic distinction. The question you need to be asking is not whether the linear regression is a property of the data set or the mathematical manipulation (trivially it is a property of the data set). What you need to ask is, is it a useful property to know. And, as with any question of usefulness, that depends critically on the use intended.
  46. Still Going Down the Up Escalator
    Tom @125 "I don't know if that is Briggs main point..." It's probably not his main point - I misspoke. He's primarily arguing for the use of predictive statistics, which is not standard in most fields. And because frequentist interpretations are counterintuitive and often unrealistic, he prefers Bayesian predictive techniques. Eli @129, I don't have a problem with a global mean surface temperature. The issue comes with how uncertainty in this value is calculated and viewed, and how a change in GMST is determined.
  47. Still Going Down the Up Escalator
    Robert S is simply Essex and McKitrick dresses in fancy statistical pants. http://www.realclimate.org/wiki/index.php?title=C._Essex_and_R._McKitrick Been there, done that
    Moderator Response: [Dikran Marsupial] Link activated
  48. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I should clarify: I meant "actual contents", as opposed to "imagined contents" - a couple of reviews seemed to be based on the latter. Oddly enough, the reviews I rated unhelpful were all 1-star, and those I rated helpful were all 5-star. Hmm... coincidence?
  49. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    I had a look at the Amazon reviews, and rated them as to how helpful I thought they were. The ones that didn't actually describe the content of the book, but were full of vitriol (some of which constituted little more than a couple of insults), were rated as 'unhelpful', while the ones that described & commented on the actual contents of the book were rated as 'helpful'.
  50. Still Going Down the Up Escalator
    Tom Curtis @125,126 You're being silly now. Practically, and perhaps physically, we could never measure temperature perfectly. So we can never truly observe "temperature" You're right. From a statistics standpoint, however, the distinction is different. Let's say we have these devices which we'll call "thermometers" that measure, for the sake of simplicity, some quantity called "temperature" (though we both agreed that they don't actually measure temperature). Say we want to measure the temperature of the entire planet. It would be simply unfeasible - or even impossible in practice - to measure every single point on the entire planet, so we place a few of these devices at choice points around the planet, and with the magic of statistics, from these measurements we construct an "average" and an "uncertainty" using some or other method. This "average temperature" isn't an actual temperature which we've measured and neither is the uncertainty; they arise from the method in which we combined our sample. Is our method the true and correct method? Probably not, but we can't say that with absolute certainty. Whether it's a reasonable method is another question. Say we then compute these average temperatures in regular time intervals to find an "average monthly temperature", and we want to see what these average monthly temperatures are doing over some specified time period. So we look up some kind of statistical model, compute it for our average monthly temperatures, and out pops some parameter of that model which we'll call "slope". Is slope a feature of the data itself, or the way in which we manipulated the data to create our model? Is our model the true and correct model? Probably not, but we can't say that with absolute certainty. KR @127 "However: Are you asserting that a trend line cannot be determined (as a statistical evaluation, within stated and computed limits of uncertainty) from the data?" No, of course a trend line can be determined from the data. I might question the value or interpretation of such a metric, but not that one can be calculated. For what it's worth, it's clear that Tamino knows his stats, and he has that rare quality of being able to explain esoteric statistical methods easily to laymen, but his latest post again misses Briggs' point.

Prev  1279  1280  1281  1282  1283  1284  1285  1286  1287  1288  1289  1290  1291  1292  1293  1294  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us