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Comments 112851 to 112900:

  1. Dikran Marsupial at 09:47 AM on 15 August 2010
    Has Global Warming Stopped?
    fydijkstra "Yes, the oscillation in Akasofu’s model is super-imposed on a linear trend. We don’t know how long this trend will continue. Not to infinity of course, because nothing in the climate goes on to infinity." Yes, and the same could be said of a linear model used to determine more recent trends. It seems to me that you are being a little inconsistent there. "Here we see a multi century oscillation with a wavelength of about 1400 years" The human eye is great at picking out cycles that are merely the result of random variation. That is why science has developed the use of probability and statistics to guard against such mistakes of intuition. Again there isn't even two full cycles shown in the graph, so projecting forward on that basis is a guess, nothing more. BTW, Roy Spencer isn't the only person to have come up with a 2000 temperature reconstruction - what do the others say? "It is not possible to calculate error bars with only 10 points on a flattening curve." Nonsense, if you were fitting using maximum likelihood based methods, of course it is possible to calculate error bars. "I used this flattening function only to show, that the data fit better to a flattening curve than to a straight line." I think I may have mentioned that fitting the calibration data better doesn't mean the model is better because of over-fitting. This is especially relevant when there are only a handful of data. "When it is said that ‘global warming has stopped’ this is only about the data onto the present. Nobody denies that it is possible that global warming will resume." The principal cause of variability is ENSO, which involves a transfer of heat between the oceans to the atmosphere. That means you can't unequivocally tell if global waring has stopped by looking at air temperatures alone, as there may still be a net warming of the Earth as a whole but a transfer of heat from the atmosphere to the oceans. The test does show that air temperatures haven't risen much (if you choose the start date in the right place).
  2. Why I care about climate change
    Sorry, truncated my remark there. I've been looking at the whole adaptation thing (which, no surprise we're going to be doing more or less, regardless of how we feel about mitigation) and among other factors in adaptation costs is how to account for direct impacts of a transitional climate. For example, there are twenty million people out of their houses today in Pakistan due to the recent flooding there, apparently much of the housing stock being destroyed beyond repair. Now, rather than argue about whether this is entirely due to climate change or entirely because of natural variability, we can take a statistical perspective and say that some proportion of these people need new homes due to a change in climate. Let's take a conservative approach and say that only five million are homeless due to climate forcing, arguably a reasonable number when the flood probability itself is taken into account. That number has to be entered into a ledger and stacked against benefit. There are myriads of details like this to take account of, "detail" perhaps being a poor choice of word. I use it because the intricacy and scale of this situation makes some millions of persons forced out of their homes into a "detail." See Tol, Stern and their citations for more information.
  3. Has Global Warming Stopped?
    fydijkstra at 05:48 AM on 15 August, 2010 To me that's simply too much ad hoc-ery to be realistic fydijkstra. (i) Braun et al (2005) explicitly rule out the 1470 year cycle for Holocene events. Their tentative conclusion for the driving of Dansgaard Oescher phenomena relates to the possibility of threshold events resulting from meltwater pulses involving massive N. Hemisphere ice sheets that result in large temporarily perturbation of the thermohaline circulation with dramatic and rapid effects on temperature in the N. Atlantic. We know these processes have nothing to do with current global warming. In any case the current warming is out of phase with the supposed "cycle" (if the peak of the last cycle was around 800-900 AD then we shouldn't be getting a new peak until 2300-2400). Or are you suggesting that we've got another 300-400 years of relentless warming due to some uncharacterised putative cycle? (ii) This seems a little unlikely in the context of the Spencer/Loehle and Akasofu's notions. Firstly, if one were to take the Spencer/Loehle sketches at face value, then we should take on board that their sketches only go to 1935. If we add on the real world warming since then, current temperatures are already well above the supposed maximum of the Loehle/Spencer sketch you reproduced. We're surely much warmer than we should be if our temperatures were dominated by your 1500 year cycle which projects a substantial warming from natural causes still to come... (iii) Akasofu proposes a linear "recovery" from the LIA that continues to this day and through the next ~ 100 years. That seems astonishing to me. It implies that the Earth has a much higher sensitivity to changes in forcings than current understanding would support, and that the climate system has such an extraordinary inertia that "recoveries" (from temperature perturbations) are dominated by processes with time constants on the century timescale or longer (how can this possibly be true?). Let's hope that Akasofu isn't correct else we're probably in a lot more trouble than we think we are! (iii) Of course we probably don't believe Akasofu's ad hoc-ery if we think about it for a bit. Looking at the temperature record (reconstructions and direct measurements from the mid 19th century) indicates that "recovery" from the LIA was largely complete by the early 19th century. (iv) I suppose the other problem inherent in ad hoc-ery is that the ad hoc decision to project the "Braun et al" cycle into the Holocene (where Braun et al state it doesn't apply) seems entirely incompatible with Akasofu's ad hoc construction. Akasofu's sketch doesn't show any of these supposed 1500 year cycles? And while according to Akasofu, we should be already heading into a cooling phase which will continue for another 20-odd years, according to the 1500 year cycle idea we should still be on a rather relentless warming "curve" that should continue for another 300 or more years... (v) Is there a good reason for rejecting everything we know about the climate system, and basing our ideas on mutually incompatible ad hoc notions? I can't think of one!
  4. Why I care about climate change
    GC, you're speaking of net benefit, aggregate so to speak?
    Moderator Response: Great discussion to take into detail on the thread It’s Not Bad (Positives and Negatives of Global Warming).
  5. gallopingcamel at 08:46 AM on 15 August 2010
    Why I care about climate change
    scaddenp (#140), Good question---"What would convince me that AGW is real?" Actually, I am already convinced but as I have said several times on this blog, I see it as a small beneficial effect rather than a problem (see #111 in this thread for example). You are probably right to suggest that next year will be cooler. The ENSO and PDO cycles will drive temperatures down for a while but in 20 to 30 years the trend will be up again. That is what I think of as Mother Nature revealing herself. Adding another 20+ years to the existing ~37 years of satellite data will greatly improve our ability to critique predictions by the IPCC and others.
  6. Has Global Warming Stopped?
    Presuming for a moment Akasofu were right, I'm sure I'm not the only one to point out that what we're doing to the atmosphere will be added to whatever Akasofu's model might predict, which in turn is paltry in comparison to the GHG effect. So ~0.015 degrees C warming per decade per Akasofu will be added to the observed ~0.13 degrees per decade per anthropogenic forcing. Of what relevance is Akasofu's work right or wrong? Much? Little?
  7. Has Global Warming Stopped?
    Dikran (#65) your 5th remark: “but it is super-imposed on a linear function of time, so it too goes on to infinity.” Yes, the oscillation in Akasofu’s model is super-imposed on a linear trend. We don’t know how long this trend will continue. Not to infinity of course, because nothing in the climate goes on to infinity. We can look at Roy Spencers reconstruction of 2000 years of global temperatures. I gave the link in my previous posting, but here is the graph. “it would be interesting to see the error bars on your flattening model. I suspect there are not enough observations to greatly constrain the behaviour of the model beyond the calibration period, in which case the model [is] not giving useful predictions.” It is not possible to calculate error bars with only 10 points on a flattening curve. I used this flattening function only to show, that the data fit better to a flattening curve than to a straight line. This is only about the data onto the present, it is not a prediction. When it is said that ‘global warming has stopped’ this is only about the data onto the present. Nobody denies that it is possible that global warming will resume. SNRatio (#69): “The simple Akasofu formula "anomaly = LIA recovery + MDO" predicts falling temperatures now - and therefore I wonder if it is not already partly falsified.” No, the Akasofu model does not exactly predict the year when the falling temperatures should continue. Moreover, just as with the model of ever rising temperatures, there is noise in the data. Akasofu’s model perfectly fits with the data so far. “The trend also seems rather speculative: What is the physical basis for this continuing "LIA recovery" in the 21st century?” See my above given reply to Dikran.
    Moderator Response: See the Skeptical Science posts are "We’re coming out of the Little Ice Age" and "Climate’s changed before."
  8. NASA-GISS: July 2010-- What global warming looks like
    I should add, Eric, that if you want to get calibrated against the level of effort required to mount a useful discussion here, look for examples by Berényi Péter. Péter puts a serious amount of hard work into teasing out quibbles he has with climatology. Meet or exceed the metric Péter provides when it comes to showing how a substantive argument against expert knowledge can be attempted and you're doing ok. Again, "I doubt it" is not an argument.
  9. NASA-GISS: July 2010-- What global warming looks like
    Eric, you're hypothesizing about Meehl's paper without doing any work to support your hypothesis. "I appeal to myself as an authority, take my word for it." Not persuasive. Rumor has it that Meehl replies to polite inquiries. Why not ask a real expert? As to record high minimums clearly you can type, you've got an Internet connection, you're capable of performing your own literature search. You'd nonetheless like to send somebody (me, for instance) beavering away to produce some references for you thereby supplying you with fresh opportunities for making lazy assertions. Forget it; I did a good faith effort for you once, not again on this topic. Do your own work.
  10. 3 levels of cherry picking in a single argument
    #34, I agree. David #3 wonders if the problem with deniers is they can't read charts. Probably they can't - but they can read tea leaves, and they tell what most scientists won't say outright - fixing this problem (it's no longer fixable) would have required radical sacrifice in lifestyle on the part of every citizen of developed countries, and a universal one-child (or less) policy. The scientists and climate change activists who promise that we can convert to clean energy and restore the economy without giving up our fuel-gobbling toys are making a huge mistake. The deniers know instinctively that isn't true. You don't need charts or graphs to see where how this movie is going to end. Scientists should stop pussyfooting around and demand that fuel be rationed on a per-person basis, and restricted to only the most essential purposes until it is replaced with sustainable sources for electricity. Don't you have kids too?
  11. Extreme weather isn't caused by global warming
    #2: Something the Bush admin said in 2008 seems to be correct? "As options dwindle for negotiating a global pact to fight climate change, the United Nations is pointing to today's "extreme conditions." "As global temperature records have been set for the early summer months, states and cities are also setting hundreds of temperature records. ... Unfortunately, climate models indicate that an average summer in 2050 will have even more days topping 90°F if global warming continues unabated."
  12. Increasing CO2 has little to no effect
    That good friend of AGW, Dr. Roy Spencer, has empirical evidence for the greenhouse effect. "Particularly difficult to grasp is the concept of adding a greenhouse gas to a COLD atmosphere, and that causing a temperature increase at the surface of the Earth, which is already WARM. This, of course, is what is expected to happen from adding more carbon dioixde to the atmosphere: “global warming”. ... This [Spencer's experiment] shows that the addition of an IR absorber/emitter, even at a cold temperature (the middle level clouds were probably somewhere around 30 deg. F), causes a warm object (the thermopile [in his IR thermometer]) to warm even more! This is the effect that some people claim is impossible.
  13. 3 levels of cherry picking in a single argument
    Scaddenp writes (first comment), apropos of why there is so much climate denial, "There must be a lot of people with shares in fossil fuel industry." We _all_ have shares in the fossil fuel industry. Not necessarily stock, but a frightening, radical dependency. Coal and oil feed us, light us, clothe us, entertain us, truck and ship all our crap and necessities around the planet, move us back and forth to our jobs and vacations, build our homes -- keep the whole industrial circus from collapsing into apocalyptic chaos and mass death. Denialism's reassurance that all is basically well, that all will continue to be well, that we can all continue to do our familiar things and burn our familiar fuels and live our familiar way and be safe forever, that there is nothing fundamentally, fearfully wrong with the planet or with our dream of technology-driven prosperity and progress . . . it's very tempting.
  14. Why I care about climate change
    #139: "When a student finds something in a science text book that makes no sense he asks his teacher for an explanation." These days, students go to the interwebs (and each other) well before asking their teachers. That's why 'science' via echo-chamber-blogosphere is so dangerous and why your next statement so important. "I hope we can agree that widespread scientific illiteracy is dangerous when our survival depends on sophisticated technology. " Amen to that. Illiteracy is dangerous in all forms, but scientific illiteracy is like not knowing which is the business end of a loaded gun.
  15. NASA-GISS: July 2010-- What global warming looks like
    michael sweet The average temperature on the Moon is fairly meaningless in this context given temperature swings that take minutes relative to daylight and night hours on Moon that last roughly 300 hours. Please check the curves here and see temperature transitions... in evacuated tubes... on the Earth. http://en.wikipedia.org/wiki/Solar_thermal_collector
    Moderator Response: Your comments on this topic belong on the thread CO2 effect is weak.
  16. Eric (skeptic) at 22:33 PM on 14 August 2010
    NASA-GISS: July 2010-- What global warming looks like
    Doug, am I not going to get any links about studies of the effect of urbanization on record high minimums? If not, why not? I can obviously see why higher *average* minimums might be interesting to some, and the Easterling links are convincing enough. But this thread is about records, not averages. Am I not going to get an answer to why Meehl did not have any discussion of urbanization in producing his chart in the head post, even just a sentence referring to Weber? It would not be directly relevant since Weber studied the effect of urbanization on a city by city basis with all of his available data (no selection bias), but at least it would be something. Appeals to authority only work if the authority has shown some thoroughness, otherwise you need a new authority.
  17. NASA-GISS: July 2010-- What global warming looks like
    miekol at 17:35 PM on 14 August, 2010 I'm getting a distinct feeling this is not a science site. Its as its title says,"skeptical about global warming skepticism," This is a science site. When you have any concpt of science maybe you will be taken seriously. Until then, whatever.
  18. NASA-GISS: July 2010-- What global warming looks like
    I'm getting a distinct feeling this is not a science site. Its as its title says,"skeptical about global warming skepticism," and unless one is pro GWers its pointless posting because any negative posts to pro warming get deleted. [further thoughts off-topic for this thread deleted]
    Moderator Response: To the contrary, Skeptical Science deals with a multitude of arguments and as long as they do not degrade into insults, accusations of dishonesty, hypotheses of general corruption of the entire scientific community or the like they are allowed to follow their natural course. However, in the interest of encouraging useful conversation, Skeptical Science does not entertain bundled collections of misconceptions but instead deals with each misconception individually. By using the "Search" function at upper left, you will most likely be able to find a suitable location to take your concerns. More information on expectations for comments may be found at the Comments Policy page.
  19. NASA-GISS: July 2010-- What global warming looks like
    I don't mind my comments being removed by moderators, and I was right-on-target wiuth mine. And I am on "your side" whatever that may be. But. If you are going to remove my post at least have the courtesy to send me an email which I use to register with your site so I b) know what it is I said that offended your moderator. I know what am talking about and I ave te shingle to prove it.
    Moderator Response: We apologize for any unintended offense. It may be that your comment was one of several diverging into a discussion of the role of C02 as a GHG which were removed after the pointer to Miekol upthread. If you feel your comment was removed in error please feel free to post it again.
  20. NASA-GISS: July 2010-- What global warming looks like
    Interesting perspective there, Eric. The Weber paper was about the Alps in Europe, found minimum and maximum temperatures to be increasing at both low-lying stations in Central Europe as well as mountain tops. The mountain tops of the European Alps are not urbanized and of course are quite distant from Washington, D.C. which although a sprawl has not yet grown across the Atlantic. As to Meehl, can you show that the change in ratio is due to urbanization? Remember, when you convey the impression you know better than experts on a given topic, you incur a sort of debt against your credibility. You can't just create an argument out of thin air by implying you're more expert than Meehl and his coauthors, you have to show how, specifically by improving his results. That's how you pay for credibility, by doing the work necessary to back up assertions. Not an assertion? Simple doubt is not an argument.
  21. Eric (skeptic) at 13:55 PM on 14 August 2010
    NASA-GISS: July 2010-- What global warming looks like
    Doug, thanks for the links. The Weber paper (last link) confirms what one forecaster alluded to here in DC in a July forecast discussion (actually the Sterling VA office) which was that the record high minimums are affected by urbanization in DC. The Weber paper says there is little effect on record high maximums. I see the Meehl paper used 1800 stations out of 11,000 or so. There's no discussion of that possible urban bias in the paper for station selection. As with the record high mins, an increasingly urbanized area is also less likely to reach new record low mins. RBW, for the record I am referring to urbanization (the process), not urban versus rural (static). Records, unlike averages, cannot be homogenized.
  22. Why I care about climate change
    "I guess we will continue locking horns until Mother Nature reveals herself. I suspect we will not have to wait much longer." Hmm, could I be hopeful in reading this, or do you actually mean that you believe that suddenly AGW is going to get away and are expecting a down trend any day? Well I can predict with considerable confidence that next year will be cooler than this year. However, the interest will be comparing temperature with previous La Nina's of same magnitude. Not the start of the cooling trend - El Nino will return. GC - can you tell us what data would finally convince you that AGW is real? 10 year from now and warming continues apace, will you still be finding reasons why its not largely due to us? With so many predictions from AGW it is easy to see what data would could me and others to rethink our position. What would it take from you?
  23. The Skeptical Chymist at 11:28 AM on 14 August 2010
    On Statistical Significance and Confidence
    Barry @46 Don't stop asking questions, even if you think they are naive, that's how we learn. Looking at your question, if you are saying the graph suggests the rate of warming in each decade is increasing I think you are over-interpreting the results. But I do think the results suggest that the climate has continued to warm each decade for the last 30 years. There were several decades last century when (due to aerosol buildup) the climate didn't warm. Therefore, adding recent decades where warming occurred will increase the proportion of decades showing warming and increase the century trend. I think this result would occur even if the most recent decade had warmed at the same or a slower rate as past decades. At the same time, the fact that the trend keeps increasing when you add in the most recent decade does show that warming continues.
  24. Has Global Warming Stopped?
    Any thought that warming 'stopped' should be quashed by the July RSS temperatures. This graph shows global (-70 thru 82.5 lat) temperature anomalies. I've calculated an average for Jan-Feb-Mar and one for Jun-July-Aug, setting the times for each average accordingly. The dreaded straight line trend is the same for both, representing 0.17 degC/decade. I like the seasonal averages: nobody remembers what the average temperature was for a given year, but we sure do take note of the extreme summers and winters. Despite the three cold winters ('85,'89,'93) and corresponding mild summers (one cooled by Mt. Pinatubo), its inconceivable that anyone looking at this graph could not see the upward trend. Yeah, its a short time frame (although 30 years is, by most accounts, a generation). So the predictable next step is to condemn all satellite data, as discussed in #67-68 above.
  25. NASA-GISS: July 2010-- What global warming looks like
    Even though Mars’ atmosphere is 97% CO2, there is no runaway greenhouse effect on that cold planet. But there should be if the proposition of high levels of CO2 can cause a runaway greenhouse effect. It doesn’t so how could Earth’s 0.038% CO2 cause such an effect?
    Moderator Response: Miekol please note the link above directing you to a suitable thread for discussing the potential effects of C02 on atmospheric temperature. Better yet, here it is: How do we know more CO2 is causing warming? Thanks!
  26. On Statistical Significance and Confidence
    Dikran #57 is correct - there are procedures to correct the number of degrees of freedom (and thus cause a corresponding loss of power) when you think there's something up with the normality of a distribution. This can cause less power loss than the use of a non-parametric statistic, so can be desirable. There are also statistical tests available which can tell you if a non-normality correction is justifiable. In the case of the two charts that BP has posted in this thread, I can pretty much guarantee by eye (from a decade or so of experience) that you'd just be losing power for the sake of it if you insisted on correcting their linear model statistics for non-normality. Generally the linear model stats are pretty robust to moderate deviations from normality, so no need to throw the baby out with the bathwater, unless the p value based diagnostics tell you otherwise.
  27. NASA-GISS: July 2010-- What global warming looks like
    Actually Miekol there are not two sides to every debate, in fact some things are effectively beyond debate and to take some positions may be something adults do but will yield no improvement in understanding. Regarding the effect of C02 as a trace gas, here's where to go with that: How do we know more CO2 is causing warming?
  28. NASA-GISS: July 2010-- What global warming looks like
    What's kinda funny is that the denialists who are citing the UHI effect don't seem to know what it is. Hint: it isn't the fact that the middle of a big city is warmer than the nearby rural areas. That's a pretty well-established, well-understood phenomenon that no scientist disputes. RSVP: Thermal inertia can be viewed as the rate of change in the temperature of a system as a function of the rate of heat input. Compare the heat capacity of the planet's oceans to the current planetary energy imbalance. One is a big number, the other is quite a bit smaller. fydijkstra: 12 months isn't irrelevant for a running average, it's the length of time that will average out the seasonal variations. 11 years is useful, too, as it will tend to average out the solar cycle. Somewhere in the 5 to 7 year range is useful, too, since it will average out the ENSO cycle. Also, since we're talking about GISS measurements, 2005 was the warmest year, not 1998. 2009 and 2007 were both slightly warmer than 1998 and 2002, but the four years are probably statistically tied for second-warmest. You must think it a remarkable coincidence that all five of those years came in the last 11 of a 130 year history, and that the 9 warmest years on record came within the last 11 years.
  29. NASA-GISS: July 2010-- What global warming looks like
    Its called being adult and having an adult conversation David. And doug, I've not said "I disagree." There's two sides to every debate. I enjoy trying to understand the world around me. I find it difficult to accept that its man made CO2 that is the cause of climate change. Do you know that in every 85,800 molecules of dry air only 33 are CO2. And of those only 33 is man made. That's one in 85,000. If you include water vapour its even less. http://en.wikipedia.org/wiki/Atmosphere_of_Earth#Composition How is it possible a one in 85,800 atmospheric molecules can be the cause of climate change?
  30. NASA-GISS: July 2010-- What global warming looks like
    Miekol it's worth stopping and considering (honestly-- step back, calm down, think about it) that your opinion w/regard to our ability to perform useful measurements on the behavior and direction of our climate is quite divorced from what our best experts tell us. "I disagree" is not an argument, not a means of improving our understanding. "I disagree and here's how, specifically, coherently and constructively" using means and methods specific to the case in consideration is a better approach as well as actually being a complete attempt at argument. Ideology or politics really have nothing to useful to say about what the physical world of instrumentation tells us.
  31. NASA-GISS: July 2010-- What global warming looks like
    David Horton: It is striking to see posts like Miekol's right after yours. There are several people like him/her posting on Skeptical Science right now. How can you reply to a post like that?
  32. NASA-GISS: July 2010-- What global warming looks like
    Miekol: Is the ice core data for 400,000 years a long enough record for you? Or do you insist we wait for 5,000 years to get direct temperature measurements? These data show that current warming is not natural and can cause serious problems. Your last post is too extreme for me to reply to. You need to read less denial websites and become familiar with the science. This web site has a lot of good information for the novice.
    Moderator Response: Miekol's last post was moderated out because it was off-topic and primarily ideological/political. Please try to stay on topic.
  33. More evidence than you can shake a hockey stick at
    JohnD, water vapor can store heat in both latent and sensible forms. Latent heat is not what's measured w/a thermometer. What's the capacity for sensible heat of water vapor in comparison w/the rest of the gases in the atmosphere? Water vapor in our temperature realm has a specific heat capacity of ~1.8kJ/kg K versus dry air at ~1.0 kJ/kg K. The mean mass of water vapor in the atmosphere is something like 1.27 × 10^16 kg, the dry air mass 5.13 × 10^18 kg. We don't need to work the arithmetic to see that water vapor is not the dominant reservoir of sensible heat in the atmosphere.
  34. NASA-GISS: July 2010-- What global warming looks like
    #42: better tell that to the vast number of "skeptics" who declared that temps would continue to decline and that we were rapidly headed for a Maunder Minimum when the global average temps had a slight La Nina induced drop in 2008. Looking at the 2009 and 2010 data, it seems that their prediction didn't quite come true.
  35. NASA-GISS: July 2010-- What global warming looks like
    A period that spans only five decades is nowhere near long enough when it comes to the study of planet climate. As the writer says, "we're looking at a system with enormous inertia and so climate shifts will generally show up as incremental creep over a long period of time." Even centuries will not encompass the BIG PICTURE. A minimum would be five millennium.
  36. More evidence than you can shake a hockey stick at
    doug_bostrom at 09:18 AM, doug, I take it then that you do not accept that the atmosphere could be warmer because of the increase in heat content bought about by an increase in water vapour. What carries the heat content that determines the measured temperature of the atmosphere if not primarily water vapour?
  37. NASA-GISS: July 2010-- What global warming looks like
    #32: "In Deniaworld it seems there is no measurement, no series of measurements; no extreme unprecedented weather event, no series of such events; no series of different extreme events in different regions; ... there is nothing, literally nothing that can't be arbitrarily dismissed," You're forgetting the two weather events that Deniaworld uses to set its clocks: the 1998 high temps (hence no warming since then) and the 2007 min ice extent (hence the Arctic hasn't melted at all since then). When you stake your position on only those facts you want, life is sweet. And hence all others must be wrong.
  38. Of satellites and temperatures
    BP, sounds like a literature search is in order. I see something like 11,000 hits on Google Scholar using the term "derivation atmospheric temperature microwave sounding." Adding "calibration" winnows the list down to about 5,000 hits. For sure some duplicates and ringers I'll bet, but somebody appears to be on the case.
  39. More evidence than you can shake a hockey stick at
    ...the basis of the greenhouse theory is that the heat content of the atmosphere is absorbed and then carried by those gases that have been identified as greenhouse gases. Stopped me in my tracks, that did. The heat content of the atmosphere, primarily carried by the greenhouse gases, is measured as a temperature... And again. Bruising, really. Letting aside those problems and ignoring the flawed analogy between the taste of coffee versus phase changes in water and what causes and maintains them, the reason why the atmosphere is more humid is because the atmosphere is capable of carrying more water vapor before it condenses. In other words, atmospheric humidity is increasing because an increase in temperature allows it to do so. This is not even slightly complicated and it just boggles my mind to see the gymnastics some of us will go through to avoid looking at a graph and dealing with a conclusion. Or do we believe in an alternate explanation for why precipitation frequently happens as moist air is driven up and over mountains, experiencing adiabatic cooling and thus following the prediction that water will precipitate as the atmosphere approaches saturation? And of course, it's worth noting this increasing humidity is following the simple prediction that a given amount of C02 forcing will be followed by amplification by increased water vapor in the atmosphere.
  40. On Statistical Significance and Confidence
    BP #50 "Yes, but you have to get rid of the assumption of normality. Temperature anomaly distribution does get more regular with increasing sample size, but it never converges to a Gaussian." From a theoretical perspective this is an important consideration, but from a practical perspective it often makes little difference. It is of course quite reasonable to use non-parametric methods whenever you think it's sensible, but NP methods will always have less power for a normal-enough dataset. So it's important to consider whether there's any practical benefit from eschewing the normal distribution. In the case of the two graphs you posted in this discussion, they're what we would consider close enough to normal as makes no odds. (I've spent some time working on this as part of my day job, to satisfy myself empirically of when NP and P approaches are best)
  41. Dikran Marsupial at 09:03 AM on 14 August 2010
    On Statistical Significance and Confidence
    tobyjoyce@51 - maybe a student-t distribution and vary the degrees of freedom to match the kurtosis. IIRC the student-t distrubution can be represented as an infinite sum of Gaussians.
  42. Berényi Péter at 09:02 AM on 14 August 2010
    Of satellites and temperatures
    #17 Ned at 04:52 AM on 14 August, 2010 Bandwidths for AMSU are here, along with a great deal of additional information that might be of interest. Bandwidths for MSU are here. Thanks. I see AMSU-A 5 is actually two closely packed channels at 53481 MHz and 53711 MHz, nominal relative bandwidth is 3.2×10-3 for both, pretty narrow. MSU 2 is 53740 MHz, relative bandwidth 4.1×10-3. As these frequencies are much (by more than two orders of magnitude) lower, than the typical νmax for thermal radiation of Earth, energy flux in this narrow frequency band should be proportional to absolute temperature [at low enough frequencies Planck's law can be approximated by I(ν,T)=2kTν2c-2]. However, it is true only for a black body, one for which absorptivity/emissivity is one. Temperature of a solid opaque surface can only be measured this way if its emissivity is known. With a semi-transparent medium (like the atmosphere) which has different temperatures at different depths and absorptivity can also vary, it gets much more tricky. With no additional information it is utterly impossible to recover anything remotely reminiscent to proper temperature from the signal measured. As at the TLT channel temperature is measured down to the surface, at this frequency the atmosphere should be pretty transparent (meaning it also have a low emissivity by Kirchhoff's law). So thermal radiation directly from the surface (e.g. rock warmed by the sun) also makes through and at he instrument it is indistinguishable from the portion of radiation originating from the atmosphere itself. Therefore not only a sophisticated model of atmosphere is needed to make sense of the dataset measured, but the radiative properties of the surface below have to be known as well. So this kind of temperature measurement is far more complicated than advertised and needs a lot of additional information that should be gathered (and validated) by other means.
  43. NASA-GISS: July 2010-- What global warming looks like
    batsvensson: The unusual cold in parts of Europe and the US last winter was caused by an extreme negative phase of the Arctic Oscillation, bringing cold Arctic air to lower latitudes, with warmer air flowing into the Arctic, causing the Arctic temps to rise to unusually high levels. Some info: http://nsidc.org/arcticmet/patterns/arctic_oscillation.html http://www.appinsys.com/GlobalWarming/AO_NAO.htm This has been linked to the extreme ice melt and rapid heating of the Arctic, and it is expected that we can see similar weather patterns during the coming winters: http://ipy-osc.no/article/2010/1276176306.8 http://ipsnorthamerica.net/news.php?idnews=3127
  44. More evidence than you can shake a hockey stick at
    CoalGeologist at 03:34 AM, the basis of the greenhouse theory is that the heat content of the atmosphere is absorbed and then carried by those gases that have been identified as greenhouse gases. Water vapour is the primary and majority greenhouse gas and it only becomes a gas, and thus a greenhouse gas upon absorbing heat energy at the earths surface, which it then transports aloft where it is gradually dispersed, finally giving up all the heat where the highest clouds are formed. The heat content of the atmosphere, primarily carried by the greenhouse gases, is measured as a temperature, thus rather than considering rising humidity as confirmation of warming, they must be considered as one and the same, the temperature being merely a measure of the heat content residing primarily within the water vapour. How much water vapour is moves into the atmosphere at any time is dependent on what conditions prevail on the earths surface where the atmosphere and the surface waters interact and not the temperature of the atmosphere, because it is the water vapour itself that primarily determines the temperature of the atmosphere. Much like those who struggle with their coffee each morning. By whatever means they measure the sweetness of the coffee, there will be a correlation found between the measure of sweetness and the amount of sweetener being added to the coffee. For rising humidity to be used as proof of rising temperatures, so too could rising sweetener levels be used as proof of a rising measure of sweetness. That seems rather confused to me. It is not the rising measure of sweetness that causes the rising level of sweetener, but that is what has been suggested regarding the atmosphere.
  45. NASA-GISS: July 2010-- What global warming looks like
    Bat the best way to answer your questions with the least ambiguity would be to travel to the NOAA-GISS and WMO links in the article. Or do a literature search and see what's been predicted and what's being observed. However-- boiling down this post to fewer words-- while attributing any single event to anthropogenic climate change is a very high bar to cross the trend of weather extremes we're seeing is in keeping w/predictions and could reasonably be considered a signature of a process dominated on the short term by natural variation but with an overwhelming trend. That's the point both NASA-GISS and WMO are making. Regarding last winter, I'm not an expert but I've read that it was down to natural variation, hardly unexpected as a glance at a host of data shows (see the NCDC data visualization tool linked near the beginning of the article). As both the WMO and NCDC say, as La Nina exerts itself (herself?) we can expect to see a drift back to what are considered more normal conditions but we should not expect trends to vanish. The real story is neatly encapsulated-- variation and all-- in that 12 month running average global mean temperature graph. A picture really does tell a thousand words. A lot of us are terribly dismayed with what such pictures tell us so our first instinct is to disbelieve them. Unfortunately disbelief is not an argument and can't stop the processes driving that graph upward.
  46. 1934 - hottest year on record
    Broadlands, it's no wonder NCDC doesn't want to reply to letters containing questions they've taken pains to answer in bulk. Here's Peter Hogarth's comment conveniently supplying links to the information you claim you can't find. Go read, or choose to remain mystified. Your choice.
  47. NASA-GISS: July 2010-- What global warming looks like
    @michael sweet at 07:36 AM on 14 August, 2010 A lot of snow is not the same as record cold. This is strawman. The rest of your comment is as a red herring.
  48. NASA-GISS: July 2010-- What global warming looks like
    Michael - yes indeed - "as soon as one argument is shown to be false they make up a new one". The obvious question to ask them would be - what would you expect to see happening if the CO2 levels in the atmosphere were rising rapidly in the last 30 years or so and with them global temperatures were increasing rapidly? Would you really expect to see nothing happening given that we know about the major climatic shifts the Earth has undergone n the past? And do you imagine that if you pretend that every single unprecedented (I use the word literally) event is somehow "normal" then you can also pretend that rising CO2 levels (with known physical consequences) and rising temperatures are not happening? The really depressing thing, as readers will be aware, is that the current Australian government's plan (the Opposition has no plan at all) to deal with global warming is to hold a conference of "ordinary" people (certainly not climate scientists) to decide what to do. It has been pointed out - http://davidhortonsblog.com/2010/08/11/deliver-da-letter/ - that such a conference would closely resemble the kind of discussion we see in this thread and many others. A denial, based on the most improbable propositions, that there is any problem at all.
  49. NASA-GISS: July 2010-- What global warming looks like
    @michael sweet at 07:36 AM on 14 August, 2010 So many hot records have been set this month that it may no longer be up to date. I don't know where you live, but I can hardly say any heat records been set this month where I live (western Europe) on the contrary this month may be just another "normal" or slightly cooler in the record - but we are not even half way so still far to early to tell what it will be.
  50. NASA-GISS: July 2010-- What global warming looks like
    @doug_bostrom at 04:16 AM on 14 August, 2010 Unfortunately I can not access the full article, I also noticed this article is published 2006 and obviously they can not have any opinion in that paper whether last winter was due to climate or weather or even if it was extreme – if you ask me I wouldn' t say it was extreme more like winters used to be 15-20 years ago about. Anywat, that does not matter. What I am asking for is statements from official institute about what have happen, that is I am not asking for predictions but explanations. Like the one that has been made about the current wild fires in Russia and flooding in Pakistan as contrary to explanation made before about extreme weather phenomena - these has been explained as variation in weather and nothing more, however variations that we can suspect to see much more often – the difference now is that this latest explanation seams to claim that climate change is a direct cause (and I think such strong claims never been made before, has it?) Secondly since this winter was a mess and is directly related to this summer it falls natural to ask the question – was this winter also due to a climate effect or was it just natural variations?

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