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Comments 64201 to 64250:

  1. Still Going Down the Up Escalator
    RobertS @ :for some unobservable, unverifiable parameter like "slope" under the assumption that your straight line model is correct (and several other similar comments) You keep putting terms like "slope", "average", etc. in scare quotes, as if they have no meaning. You seem unwilling to agree that such an entity can be a property of the underlying process itself, rather than the analysis of the data. Let's look at calculus. Let's take the function Y=x^2. Not linear. Yet calculus says that we can calculate the slope at any value of X by taking the derivative of Y with respect to X. Numerical methods also tell us that we can get a pretty close approximation to that slope by taking pairs of (X,Y) values close to that point and calculating the slope of the linear segment between the points. Is that slope a property of the function Y=X^2, or a property of the analysis? Can the results of the analysis tell us anything about the function? Can you give a straight answer without resorting to an argument that tries to pretend that words don't mean anything?
  2. Still Going Down the Up Escalator
    EliRabett, Thanks for the example. Are observations are uniformly spaced? I assume that daily or seasonal cycles are already averaged out in some way? I don't think those are difficult problems but the methods can sometimes be controversial. Once the cycles are removed is there any other role for spectral analysis? Are there any a priori statistical tests for the residuals or trends in the residuals? By what method are nonlinear trends in the residuals measured? How do we know that we have sufficient data for that method?
  3. NASA Mission Takes Stock of Earth's Melting Land Ice
    and, Jim, some won't. Some will fall on land. And some of that will run off into streams and eventually reach the sea, and some will soak into the soil, and some will eventually make back into deep aquifers... ...so you can't look at this by pretending that one small portion of the water cycle is everything. Taking the number that represents the removal for irrigation and expecting that it all ends up raising sea level is wrong.
  4. NASA Mission Takes Stock of Earth's Melting Land Ice
    But muoncounter, what goes up by evaporation comes down as precipitation, and depending on the location, some of that will end up in the ocean.
  5. NASA Mission Takes Stock of Earth's Melting Land Ice
    Norman#24: "water is being added to the surface system. Some will be impounded, some will end in the sea." And some will end in the atmosphere. Per the USGS, ... of the water used for irrigation, only about one-half is reusable. The rest is lost by evaporation into the air, evapotranspiration from plants, or is lost in transit, by a leaking pipe, for example. Sounds like there is a high level of uncertainty in the fraction of groundwater that reaches the ocean. You neglect, as well, the fact that groundwater depletion is a major factor in land subsidence, exacerbating coastal sea level rise. This is an argument so thin as to be transparent.
  6. Newcomers, Start Here
    "only have data running back to a 100 years" This is highly inaccurate. We only have instrumental data going back a little over 100 years but we have data in various forms covering millions of years. This also seeks to avoid the issue that climate theory is based on physics and validated daily in countless data sets. Do we not send a rocket to Mars because we only have data on gravity going back 200 years?
  7. NASA Mission Takes Stock of Earth's Melting Land Ice
    Norman @21, you make the assumption that extracted groundwater is not being replaced. That is not correct. Although groundwater is not being replaced at the rate at which it is being extracted in many aquifers, surface water is still making its way underground. Therefore simply taking the figure of the consumptive use of ground water as being the net addition to surface waters is inaccurate.
  8. Major Study of Ocean Acidification Helps Scientists Evaluate Effects of Atmospheric Carbon Dioxide on Marine Life
    With available instrumentation both pCO2 and pH can be measured with enough accuracy to determine aragonite saturation . We know that here along the Calif. coast we seasonally flirt with undersaturated water . Putting long term biological data sets together with carbonate chemistry requires bringing pH sensors to existing biological sites. Getting funding to maintain weekly or biweekly larval settlement studies has always been very difficult . Industry has funded a 20 year by weekly study on sea urchin recruitment in calif. and the oyster industry maintains a along term dataset for oyster recruitment in washington . Other than those two baselines we don't have have much to go on. At some point the public will demand real world evidence and maintaining a long term record will be more convincing than lab studies. Bruce
  9. Still Going Down the Up Escalator
    It might become even a teensy bit clearer if one considers a series of measurements of something unknown made in a black box with only a digital readout on the cover. Eric doesn’t know what the instrument is. Eric doesn’t know how accurate or precise the instrument is. Eric doesn’t know what the instrument is measuring. Eric doesn’t know if what the instrument is measuring is changing in time. All Eric knows is the numerical (digital) representation of what he reads on the indicator. Eric diligently records the numbers and then arranges them in a table as a function of time. We know that Eric never gives up so he gives us a long series or maybe not. Eric can now use statistical analysis to estimate the probability of there being a trend or not and to estimate the trend and the uncertainty in the trend. The residuals and trends in the residuals can be used to estimate the probability of the trend being linear or higher order (since everything reduces to a power series we don’t have to directly deal with anything but polynomials. From that point of view accepting or rejecting the hypothesis that the behavior of whatever is being measured is unchanging is simply checking if the zeroth order term in the series is the only significant one). From this POV, the residuals tell us of the summed variability of the what is being measured and the measurement device. We would, of course, have to break into the box and calibrate the instrument against a well characterized source to separate accuracy and precision.
  10. NASA Mission Takes Stock of Earth's Melting Land Ice
    Norman - It does matter in terms of sea level rise (SLR). Groundwater depletion is a serious ecological issue, reducing the carrying capacity of many regions. But the total amount of water making it's way to the oceans is what matters in terms of SLR. You have to add up all the sources and sinks of terrestrial water to see what's going on. A more recent (and complete than Chao) reference is Milly et al 2010 - Terrestrial Water-Storage Contributions to Sea-Level Rise and Variability. Considering groundwater depletion, irrigation, impoundment, etc., they state: "When we consider only those processes ... in which we place medium to high confidence, we obtain a zero net trend in sea level. This is consistent with the most likely range of ≈0 to 0.3 mm/year deduced [from external constraints] ... for the past two decades ..." (emphasis added)
  11. NASA Mission Takes Stock of Earth's Melting Land Ice
    KR @23 I think we are not on the same page. Water impoundment is not the same concept as adding water to the surface water system from groundwater sources. The number you give is for the total amount of water that has been impounded by mankind to date. The number I gave is a yearly extraction of groundwater sources and a lot of that is depleting the ground water supply at a much faster rate than entering it. This means the water is being added to the surface system. Some will be impounded, some will end in the sea. The impounded water is a static amount that will change only if new lakes are made. The irrigation is a every increasing amount. Also irrigation rates are going up so more water is being extracted. Groundwater use for irrigation - a global inventory.
  12. NASA Mission Takes Stock of Earth's Melting Land Ice
    Norman - Looking at the amount of water used is not very informative without also looking at the amount of water retained, the input to irrigation. From Chao et al 2008 - "By reconstructing the history of water impoundment in the world's artificial reservoirs, we show that a total of ∼10,800 cubic kilometers of water has been impounded on land to date, reducing the magnitude of global sea level (GSL) rise by –30.0 millimeters, at an average rate of –0.55 millimeters per year during the past half century." (emphasis added) Your assertion that there is significant sea level rise from irrigation is, in fact, incorrect.
  13. Hockey stick is broken
    KR and DB You guys are champs. Thanks a lot.
  14. NASA Mission Takes Stock of Earth's Melting Land Ice
    @michael sweet, I may be mistaken, but I believe Camburn was, in this case, referring solely to people living on Greenland. Those occupying coastal areas over the rest of the world are a different, and altogether more serious, concern. Absolutely incredible, and terrifying, the sheer scale of the ice loss per year
  15. NASA Mission Takes Stock of Earth's Melting Land Ice
    From the article "The total global ice mass lost from Greenland, Antarctica and Earth's glaciers and ice caps during the study period was about 4.3 trillion tons (1,000 cubic miles), adding about 0.5 inches (12 millimeters) to global sea level. That's enough ice to cover the United States 1.5 feet (0.5 meters) deep." One problem is that even if the ice melting halted the oceans would continue to rise at about the same rate. The result of irrigation pulling water from aquifiers that had the water locked away and now going into the surface water balance. "Of the total irrigated area worldwide 38% is equipped for irrigation with groundwater, especially in India (39 million ha), China (19 million ha) and the United States of America (17 million ha).[9] Total consumptive groundwater use for irrigation is estimated as 545 km3/year. Groundwater use in irrigation leads in places to exploitation of groundwater at rates above groundwater recharge and depletion of groundwater reservoirs." source of quote. 545 km3/year equals 5.35 x 10^11 tons of water a year. cubic kilometers to tons conversion calculator. In the 7 year period of the Grace study you would have extracted 3.745 trillion tons of water from groundwater sources that are not being recharged by surface water so this basically will add this much water to the surface (at least for many years). So the water added to the system via irrigation is fairly close to the amount of water added by melting ice. Meaning the sea water will continue to rise regardless if the ice melting stops and the problems of the future will still remain.
  16. Dikran Marsupial at 07:13 AM on 11 February 2012
    Has Global Warming Stopped?
    Eric (skeptic) "Why would linear models be exempt from that?" They are not really, if they are intended to be a model of the data generating process. However they can also be used as a method of estimating the local gradient of the data generating process, in which case they need only be locally congruent. The choice of model depends on the nature and purpose of the analysis. For the graph in 63, I would say it is not a reasonable model for "recovery from the LIA" as GMST is already higher than the temperatures prior to the LIA. See also my comments in post 64. However please do not discuss the LIA any further on this thread as it is clearly off-topic.
  17. Has Global Warming Stopped?
    Dikran, I didn't see this thread with comments when I posted on the staircase thread, only the print version. One of my questions is answered in the comments, that complex models should be congruent with some underlying physics. Why would linear models be exempt from that? Second, there is a linear trend shown in post 63 that is labeled "recovery from the LIA", which appears to be an estimate of an average natural warming trend. Is that a valid model of the "recovery" or is it invalid? (IMO, not really valid). There are a variety of arguments about the LIA and recovery from http://climate.envsci.rutgers.edu/pdf/FreeRobock1999JD900233.pdf (a heavier emphasis on volcanic activity and other natural factors) to http://www.arp.harvard.edu/sci/climate/journalclub/Ruddiman2003.pdf (natural factors are mostly cooling and warming including post-LIA is anthropogenic). I don't believe the science is settled on that topic.
  18. The Year After McLean - A Review of 2011 Global Temperatures
    Under "Short-Term Natural Temperature Influences", "aggression" should be replaced by "regression".
    Moderator Response: [DB] fixed, thanks!
  19. Still Going Down the Up Escalator
    Addendum to previous post - The model used also depends on whether that model makes physical sense. One of the primary arguments against 'step' models, even though they can fit the data with considerable statistical significance, is that physically they just don't make sense in terms of thermal inertia and the mechanics of heat transport.
  20. Still Going Down the Up Escalator
    Eric (skeptic) - The use of a linear model in the figure you reference is entirely appropriate for the question asked, which is in determining that recent warming does not fit a linear trend to the last 150 years of data. Without the linear fit in that figure, you wouldn't be able to evaluate the question. Linear fits are a minimal model, perhaps the easiest to evaluate based upon limited data - and almost always an excellent first pass. Fitting a 2nd or higher order polynomial requires fitting additional parameters, meaning more information is required to fit such a model with statistic significance. As Dikran has pointed out in several conversations, the model used when looking at any data set is dependent on the question asked, and whether the data statistically supports such a model over alternatives.
  21. Volcanoes emit more CO2 than humans
    The link to "Morner 2002" is broken. Can I get a good one? Sadly, I need it.
  22. Dikran Marsupial at 06:13 AM on 11 February 2012
    Still Going Down the Up Escalator
    Eric (skeptic) models can describe, explain or predict; how well they perfoem any of these tasks depends on the appropriateness of the model. If you are not sure what a model represents, why not ask on the appropriate thread (I?
  23. Still Going Down the Up Escalator
    I am sorry about the LIA digression, I was obviously not clear on what I meant by bringing it up in this thread. For an example, see Figure 4 here The linear trend shown there encompasses some natural warming and cooling transitioning to manmade warming with natural variations. IMO, it is not a suitable use for a linear model. According to Dikran above a model describes and explains. The use in that link explicitly predicts but is not explicit about what it is predicting (natural?, anthro plus natural? anthro exceeding natural?)
  24. Hockey stick is broken
    DB - Thanks for the links. Tristan - From that discussion: "It appears [Jolliffe] now discredits decentering, and he's entitled to his opinion. But the hockey stick remains when using centered PCA, and when using no PCA at all. The claim that it's nothing but "utterly bogus artifacts" is what's really bogus." - Tamino For those who are interested in the subject, Tamino has a fairly extensive discussion of Principal Component Analysis (PCA) which is still on the intertubes here: Part 1 and Part 2
    Response:

    [DB] Tamino also deals with the PCA/non-PCA kerfluffle in this post at RealClimate:

    http://www.realclimate.org/index.php/archives/2010/07/the-montford-delusion/

  25. Dikran Marsupial at 05:29 AM on 11 February 2012
    The Year After McLean - A Review of 2011 Global Temperatures
    McLean should be praised for having made a testable prediction, that at least is good science (Popper would have approved) even if the basis for the prediction wasn't.
  26. NASA Mission Takes Stock of Earth's Melting Land Ice
    Thanks, Yvan. I agree, if that is a real measure of aquifer drawdown then it is very worrying indeed.
  27. Hockey stick is broken
    Sorry JH Principal Component Analysis.
  28. Hockey stick is broken
    KR I completely agree with your comment. That said, I'm still interested in the whole MM03 vs MBH debacle. I can't find the original reference, I think it may be one of Tamino's vaporised posts, but here's the context from everyone's favourite website.
    Response:

    [DB] Links to the once-lost Tamino/Open Mind posts can be found in this post here:
    http://www.skepticalscience.com/Open_Mind_Archive_Index.html

    The post you seek is located here:
    http://web.archive.org/web/20080911215131/http://tamino.wordpress.com/2008/08/10/open-thread-5-2/

    The specific portion of the thread in question begins here:
    http://web.archive.org/web/20080911215131/http://tamino.wordpress.com/2008/08/10/open-thread-5-2/#comment-21873

  29. Hockey stick is broken
    Tristan - Do you have a reference to what Joliffe wrote? Decentered means are frequently used in Principle Component Analysis (PCA), and have been for a number of different analysis areas. See a quick look at Google Scholar. The various arguments I have seen about decentering have failed to show that use of decentered means invalidates MBH98, or even significantly changes the results. See Wahl 2007 as linked in the original post. While McIntyre 2004 was able to generate some 'hockey-sticks' from red noise, analysis of the eigenvalues for those shows that McIntyre was looking at noise (low correlation, lots of fairly low value components), while the MBH98 data components have only a couple of very large eigenvalues. That's how you determine whether you are looking at actual correlations (MBH98) or just noise (McIntyre). I will note that MBH98 was a pioneering paper in terms of the reconstructions - much work has followed on in both reconstruction techniques, additional and improved proxies, etc. See Mann 2007 for a partial review. All of the work supports the late 20th century being as warm or warmer than anything in the last 1200 years, and warming faster than anything we have data for. There may well be statistical arguments for/against decentered means in this field, but again - none of them invalidate the multiply confirmed results. --- What's really stunning (IMO) about this entire discussion is the 'skeptic' focus on a paper published over a decade ago, while a dozen later works using several different methods (with what should be refined techniques), are getting the same results. It's the equivalent of someone in an active field of professional research criticizing what somebody did in grade school - even though all work done since then agrees...
  30. Still Going Down the Up Escalator
    "when will we know when we have finally recovered from that LIA...?" Here's a chronology of sorts, putting the end of LIA in the 1850s. That looks similar to the pattern of this graph, which shows flattened temperatures in the mid 19th century: --source And then the modern warming began. So LIA over, we're not just 'recovering,' whatever that actually means.
  31. Hockey stick is broken
    Ian Joliffe considers MBH98 to contain 'dubious statistics' and says of the use of decentred PCA: It is possible that there are good reasons for decentred PCA to be the technique of choice for some types of analyses and that it has some virtues that I have so far failed to grasp, but I remain sceptical. Is using a decentred PCA the norm in paleo reconstructions or was it just MBH98?
    Moderator Response: [JH] Please define "PCA". Thank you. [Sph] John, PCA is Principle Components Analysis, a statistical technique whereby components are isolated and prioritized.
  32. Still Going Down the Up Escalator
    Sphaerica - Very interesting references. While the exact causes of the LIA are not entirely fleshed out, it's clear that anthropogenic greenhouse gases are the overwhelming cause of current warming - not natural forcings, which we have a fairly good identification of. If, on the other hand, we have to placate some great Sky God, I definitely want to be on the committee selecting who gets tossed into the volcanoes...
  33. Still Going Down the Up Escalator
    140, KR, A brief digression... another theory for an influence (far from sole cause) on the LIA is the recovery of forest land, which drew down CO2 levels by about 4 ppm, from the combination of population first lost in Europe due to the Black Death and 150 years later in Native American populations due to the introduction of European diseases like smallpox. In effect, we had two major population losses which allowed land that had been cleared to be reclaimed by forests, taking CO2 out of the atmosphere. Forest re-growth on medieval farmland after the Black Death pandemic—Implications for atmospheric CO2 levels (Thomas B. van Hoof et al, 2006) Effects of syn-pandemic fire reduction and reforestation in the tropical Americas on atmospheric CO2 during European conquest (Nevlea and Bird, 2008) I have no idea how viable the theories are... but it's another example of trying to understand the system and the "natural variations," rather than just saying "Sky God angry... find virgin sacrifice, make Sky God happy... ugh!"
  34. NASA Mission Takes Stock of Earth's Melting Land Ice
    From the paper this is aquifer withdrawal. Scary enough for me.
  35. Still Going Down the Up Escalator
    And when will we know when we have finally recovered from that LIA...?
  36. Still Going Down the Up Escalator
    Eric (skeptic) - "...since then there is a mixture of AGW and recovery from the LIA." (emphasis added) This is a meme I've been seeing more often recently. I will simply note that this is discussed in some detail on the We're coming out of an ice age threads. The LIA was (as far as can be determined at the moment) a combination of solar minimum and possibly (recent evidence) a triggering tipping event of high volcanic activity. While the climate warmed from that low point, that does not explain recent warming. Only AGW can account for the magnitude of climate change over the last 50 years or so.
  37. NASA Mission Takes Stock of Earth's Melting Land Ice
    What's with the large area of mass loss south of the Himalaya? Soil moisture loss? Top soil loss?
  38. Still Going Down the Up Escalator
    Eric#137: "The single number for the trend is inadequate and oversimplified." All curves (including sine curves) can be linearly approximated on a local basis; that's one of the things that makes calculus work. Fitting a linear trend is an essential first step because it forces you to justify the cause of the linear trend and it alerts you to look for departures from linearity. If those are merely residuals, you look for sources of 'noise,' as in FR2011. If those are changes in slope, you suspect acceleration (+ or -) and again go looking for causes. You seem to be suggesting a variant of the 'we don't know nuthin' myth' because we can see a linear trend and use it as a descriptor. Rather than address what is underlying the trend, imposing these arbitrary jumps doesn't seem like a valuable exercise to me.
  39. Still Going Down the Up Escalator
    137, Eric, I'm not exactly certain what you're saying... are you saying that there is no trend that is reliable? But you are right in that simply looking at the numbers and trying to tease things out without an underlying understanding is climatology climastrology [oops -- Sph]. The solution is to study and tease out the mechanics of the system, like the physics (e.g. radiative emission and absorption) and the component systems (e.g. ENSO and aerosol sources) and then to put it all together, rather than looking at any one piece of information in isolation. The wrong thing to do is to attribute great power to unknown acronyms, like a savage giving homage to the Sun God and the Wind Spirit, and then to just throw up your hands and say that no one could possibly know anything, and anyone who says they do is a nutter.
  40. Still Going Down the Up Escalator
    As a purely hypothetical example, if we had a time series with some underlying physical properties that suggested a sinusoid, it would be possible to do a linear regression on a small portion of the sinusoid (e.g. from below the origin to above). But the slope from that section would only "make sense" in the context of the sinusoid and the underlying physical causes. In the same sense a linear trend of some portion of the global average temperature should be considered as part of a bigger picture. A shorter interval (e.g. the 80's and 90's or the 2000's) would involve some natural GW and GC, AGW and possibly some counteracting aerosols. The single number for the trend is inadequate and oversimplified. Looking at longer intervals is even more problematic since then there is a mixture of AGW and recovery from the LIA. This does not seem like a valuable exercise in analysis to me.
  41. Check With Climate Scientists for Views on Climate
    Carbon500: I fail to see how your comment on Gore & mosquitoes affects my point at all. Where anyone speaking on climate science comports to the evidence, they have a certain degree of authority. Where they don't, they don't. One correct statement does not an infallible authority make, nor does one error completely discredit them.
    Moderator Response: [muoncounter] Let's all avoid being dragged into a discussion that revolves around 'things Al Gore said.' This post's topic is 'what climate scientists say.'
  42. Check With Climate Scientists for Views on Climate
    Carbon500, A google of "global warming Kenya mosquitoes" yields thousands of hits. This peer reviewed paper, among many others documents the spread of mosquito born disease. Perhaps Gore thought there were so many references that he did not need to supply one.
  43. Check With Climate Scientists for Views on Climate
    Carbon500, I notice from your link that Reiter states : "It will be interesting to see how the health chapter of the fourth report is written." In that fourth report, for which he is a Reviewer, he is referred to 3 times and has 4 references. Any idea whether he was happy with that, or if he is going to contribute to the next report ? I ask because I assume you are interested in him and his work and wouldn't just rely on 7-year old information ?
  44. NASA Mission Takes Stock of Earth's Melting Land Ice
    GRACE has demonstrated itself to be quite sensitive to glacier and ice sheet mass change and has been validated in several regions. The recent paper is an ambitious step assessing all of the worlds ice covered areas. GRACE has problems with small glaciers and has not been validated in such areas. The results from the Himalaya do not appear robust, when compared to the very extensive inventories that have documented the changes in extent of thousands of glaciers in the region and have found significant changes in areal extent across all ranges except the Karakoram. The glacier by glacier mapping completed by GLIMS or ICIMOD for example tell a different and better verified story, from Kyrgyzstan to Bhutan and Afghanistan
  45. Check With Climate Scientists for Views on Climate
    Composer99: Re your comment'With regards to non-scientists such as Gore or Flannery, such authority as they possess in communicating climate science comes from the degree to which their claims are based upon the available evidence' I wouldn't take anything Gore writes or claims at face value. For example, have a look at his book 'An Inconvenient Truth' on page 173 he states 'mosquitoes are profoundly affected by global warming.' No references, of course. Now have a look at this. www.publications.parliament.uk/pa/ld200506/ldselect/ldeconaf/12/12we21.htm
  46. Dikran Marsupial at 22:02 PM on 10 February 2012
    Newcomers, Start Here
    @debunked, just to add another example to CBDunkerson's excellent answer, the theory of plate tectonics was only suggested about a hundred years ago. We have accurate measurements of the movement of plates for much less time than that. However the plates have been in constant movement for billions of years. Is the theory of plate tectonics inherently flawed? Does this mean we can't predict the future movement of the plates? No, of course not.
  47. Newcomers, Start Here
    debunked, the argument you present disproves itself. How do we know that "the Earth's been here for many millions of years" if we "only have data running back to a 100 years"? If these 'skeptics' accept the proxy analyses which allow us to determine that the Earth is over 4.5 billion years old then they can't claim (without hypocrisy) that we only have the 131 year (since 1880) detailed surface thermometer record on which to base global warming. There are, of course, proxy records (e.g. ice and sediment cores) which allow us to gather data on temperatures, GHG levels, and other factors stretching back "many millions of years". Of course, in addition to being self-defeating, the argument is also a clear logical fallacy. You might as well say, 'Given that the universe has been here for nearly 14 billion years, Newtonian physics can't possibly be accurate because we only have data on it going back a few hundred years.' There is no inherent connection between the age of something and the amount of time it takes to understand it. Joseph Fourier first identified the Greenhouse Effect in 1826... if that isn't sufficient time to understand something then clearly we are not communicating through these computers which cannot possibly exist yet.
  48. Dikran Marsupial at 21:14 PM on 10 February 2012
    Still Going Down the Up Escalator
    RobertS wrote: "The data we are attempting to model isn't a simple straight line, else we wouldn't attempt to model it with one." That seems rather a non-sequitur. It is the underlying data generating process that we are interested in, rather than the data themselves. We do not expect this to be a linear function, we are merely trying to approximate the local gradient of the function by fitting a straight line. "We could just look at it and calculate the slope and intercept. But we do plot some straight line onto this data, and attempt to estimate the parameters of that model based on the data." There is no difference whatsoever between these two activities, the parameters of the model are the slope and intercept (other than fitting by eye is subjective and likely to be biased and hight variable). Both inferential and descriptive statistics assume that something, somewhere in the sample we are hoping to analyze is measured without error" This is simply incorrect. There are methods for inferential and descriptive statistics that assume measurement without error and there are other methods that don't make that assumption. Just because you are unaware of them, doesn't mean they don't exist (many are based on the EM approaches). Because he is not interested in the credible interval of the linear regression. He's not interested in the linear regression at all. This is Dr Briggs main failing, he is not interested in the climatology and is ignoring the purpose of the analysis (to estimate the local gradient of the data generating process). Which is why the points he is making would be valid if his assumptions about the purpose of the analysis were correct, but unfortunately they are not. "He has calculated the predictive interval of the "observables" and found a much larger uncertainty in estimates of global temperatures than stated by BEST" This is becuase he is using a definition of "warming" that is highly sensitive to the noise (i.e. unforced variability), which a proper analysis should aim to ignore. This is the reason that climatologists don't use his definition of warming, it is not a reliable indicator of underlying climate trends. "And no, not all of statistics is "predictive," but "prediction" is often implicitly assumed in some way in an analysis or interpretation" No, that is not correct, descriptive and inferential statistics do not implicityly aim to predict, they are about explanation and description. In this case, the aim is to estimate the local gradient of the (unobserved) data generating process from the data. This does not involve any attempt at prediction as we are using only a local approximation to the function of interest, so it would be unwise to use it for prediction outside the data we already have.
  49. Book review of Michael Mann's The Hockey Stick and the Climate Wars
    owl905 I made the mistake of reading Von Daniken when I was a teenager and the Daily Mail which is very similar. I won't make that mistake again with Chrichton.
  50. NASA Mission Takes Stock of Earth's Melting Land Ice
    Camburn, Your article cites 30 cm sea level rise due to melting of Greenland and Antarctic by 2050, 38 years from today. You say "no one on the continent is in peril because of this." How many million farmers in Bangladesh will be displaced in only 37 years from this sea level rise? Miami will lose close to 20% of their storm water drainage, are they "in peril" due to greater flooding? In addition, your article says that the sea level rise from the ice sheets is greater than expected from the models. Perhaps it will rise more than 30 cm as now expected. If you ignore the data it is easy to say "no one on the continent is in peril because of this." Think of the people who live near the sea.

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