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Roy Spencer's paper on climate sensitivity

What the science says...

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Spencer's model is too simple, excluding important factors like ocean dynamics and treats cloud feedbacks as forcings.

Climate Myth...

Roy Spencer finds negative feedback
"NASA satellite data from the years 2000 through 2011 show the Earth's atmosphere is allowing far more heat to be released into space than alarmist computer models have predicted, reports a new study in the peer-reviewed science journal Remote Sensing. The study indicates far less future global warming will occur than United Nations computer models have predicted, and supports prior studies indicating increases in atmospheric carbon dioxide trap far less heat than alarmists have claimed." (James Taylor)

Climate scientists have identified a number of fundamental problems in Spencer and Braswell's 2011 study which wrongly concludes that the climate is not sensitive to human greenhouse gas emissions.  One of the main problems with the paper is that it uses Roy Spencer's very simple climate model which we've previously looked at in slip up.

This simple model does not have a realistic representation of the Earth's oceans, which are a key factor in the planet's climate, and it also doesn't model the Earth's water cycle.  One key aspect in the Earth's temperature changes is the El Niño Southern Oscillation (ENSO), which is a cycle of the Pacific Ocean.  Spencer's model does not include ENSO, and he assumes that ENSO responds to changes in cloud cover, when in reality it's the other way around.

There are some other key problems in the paper.  It doesn't provide enough information for other scientists to repeat the study.  When two other climate scientists (Kevin Trenberth and John Fasullo) tried to replicate its results as best they could with the information provided, they found quite different results (see the Advanced version of this rebuttal for further details).  Spencer and Braswell's conclusions also only seems to work using the satellite data set they chose, but Trenberth and Fasullo found that using other data sets also changes their results.

Trenberth and Fasullo also found that when using a few different climate models, the one which replicated the observed data best was the one with a climate more sensitive to greenhouse gases, which directly contradicts Spencer and Braswell's conclusion that the climate is not sensitive to greenhouse gases.

It's also worth noting that the journal which published Spencer and Braswell's paper does not normally publish climate science research.  This may explain how the paper made it through their peer-review system with so many problems.  In the end, Trenberth and Fasullo find that the Spencer and Braswell study has no merit. 

  • The model it uses is far too simple to accurately represent the Earth's climate
  • The paper doesn't provide enough information to replicate their results
  • Their results depend on using one particular data set
  • They assume that ENSO responds to cloud cover changes, when in reality, the reverse is true
  • The study's conclusions are incorrect and unsupportable

UPDATE 3 Sep 2011: Wolfgang Wagner, has stepped down as editor-in-chief of the journal Remote Sensing. Wagner concluded the Spencer's paper was "fundamentally flawed and therefore wrongly accepted by the journal". More here...

Last updated on 1 August 2011 by dana1981.

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Comments 51 to 70 out of 70:

  1. Uncle Ben - "My understanding is that Spencer is looking for the sensitivity of temperature to the feedback from CO2"

    As Tom Curtis noted, what Spencer presented does not address anything commonly defined as climate sensitivity, due to the time factor. What he is looking over these short terms is the noise, not the signal - short term cloud variability is strongly affected by many variables, and climate sensitivity will be lost in the variability on these time scales. This inappropriate use of short term variations has been a pattern in a number of these studies, such as the various Lindzen and Choi papers.

    Spencer has, in addition, misrepresented the data - presenting the 6 models with the least and most sensitivity, claiming that lower sensitivities are closer fits - when he did not show additional models he had run, models with intermediate sensitivities but that better tracked the data. His test was in reality not of climate sensitivity, but of ENSO replication, a different question entirely. Not showing data in hand that contradicts his hypothesis is more than questionable.

    I would strongly suggest you read Dessler 2011 and Trenberth 2011 (links in my previous post) before claiming that Spencer is correct.
  2. Tom 50 Thank you for contributing to my education (sincerely).

    You say that equilibrium of water vapor effects are reached in a few days. That is the effect that amplifies CO2 warming, is it not? So where is the absurdity?

    I will once again say goodbye and thanks to all who have contributed useful eedback to me.
  3. Ben@52

    Increasing CO2 causes radiative imbalance. After X time, temperature rises. With higher temperature, atmospheric water vapour content increases, stablizing in a time period measured in days. That causes another radiative imbalance, which takes X time to cause another temperature rise, which leads to another increase in water vapour, ad infinitum.

    Now, Ben, are you really so poorly informed that you think that the "few days" it takes water vapour to adjust to a new temperature is the same length of time that it will take the earth-atmosphere system to adjust its temperature to the radiative imbalance?

    Or are you just trolling?

    [Hint: the time X is what you need to know before you can use observations to determine the long-term sensitivity to CO2 changes.]
  4. KR 51

    That charge has been answered quite often. It show a complete miunderstanding of the paper.

    Bob Loblaw 52 Thanks for the reassurance that I understand the process.

    The first few times around this merry-go-round is enough to establish the rate at which it is going. That is enough to permit measurement of the feedback sensitivity, since equilibrium is quickly established in the atmosphere within a month.

    No more posting for me, please. If you think I am wrong, let me live in my fantasy world in ignorance. Time will tell who is right.
  5. Uncle Ben - "KR: That charge has been answered quite often. It show a complete miunderstanding of the paper."

    I'm afraid I take Argument by Assertion as a logical fallacy.

    If you are referring (I'll note that it would help if you were more specific) to the extremely short time scales, I believe Tom Curtis has more than adequately pointed out Spencers flaws. The time frame used is simply inadequate for climate sensitivity measurements.

    If you are referring to Spencers conclusions regarding climate sensitivity and models, and Spencers egregious failure to present all the data he ran (including those that weakened his conclusions), you're going to need more support for your statements than simply asserting a "misunderstanding".
  6. Uncle Ben - While we're on the topic, you might find the discussion of the Dessler paper worth looking at.

    As opposed, for example, to Spencers rather poor work.
  7. The more I look at Spencer's argument from "The Great Global Warming Blunder" the more I am troubled by Spencer's disregard of good scientific practice. I have not looked at it in any detail before, and was only drawn into the debate because I objected to Uncle Ben's nonsense about maths never lying (whereas, of course, people lie using maths all the time). However, having been drawn in to looking at the issues, the numerous flaws in Spencer's analysis just leap out at you.

    But none more so than the one he hid in plain sight:



    Do you see it?

    It is concealed better in Spencer's later plot using a slightly different period that was reproduced by muoncounter. There Spencer labeled the x-axis "Tair change", and naturally I assumed he was discussing the change in surface air temperature. But in the plot above he clearly labels it as TMT Anomaly. That is, the temperature plot is for the TMT channel of the satellite data. I have confirmed the data in the plot reproduced by muoncounter is from the same source.

    The significance?

    About one third of the data for the TMT channel comes from the tropopause (which is not changing temperatures) or the stratosphere (which is cooling).



    As a result, the TMT trend is just over half of the TLT trend, and less than half of the trend in surface air temperatures. Climate sensitivity predicts the change in surface temperature for a given change in forcing. By using a source of temperature data which is well known to have lower temperature trends than the surface data, Spencer has weighted the scales against finding a high climate sensitivity. Indeed, if we were to use the more appropriate surface temperature, it is quite possible the net radiative feedback parameter (lambda on the plots in in the formula) would be half to one third lower than calculated by Spencer using TMT data.

    I am not suggesting that Spencer has committed scientific fraud, or that he has been dishonest. He said what he was doing. But it is a "sharp" practice which is likely to con the gullible. And of course, he has immediately taken this sharp practice to the gullible in the form of a popular book. Perhaps Uncle Ben could quote from us the sections in that book where Spencer explained that he was using TMT temperatures, and that TMT temperature trends were much lower than surface trends due to contamination from tropopause and stratospheric data. After all, we know Spencer knows about that. He, along with Christy, was part of the team that first attempted to compensate for that compensation by data analysis to produce what is now called the TLT channel.
  8. KR 51

    The title of Spencer and Braswell is about sensitivity and the accuracy of its extimation. When he presented calculations of sensitivity from IPCC modes, the ones he chose showed the range of sensitivities they embrace. It is a wide range.

    The point of the paper was not to try to fit the temperature record. To say that he chose models to do anything more than show the range of sensitivities is to misunderstand what his purpose was.

    After the storm of protest by those who wanted to do something different, he did publish results for all the models.

    About noise, if you look at the plots of points in the usual dH/dt vs dT plots, you might well think there is a lot of noise in the measurements. But when Spencer connects the dot in time order, one sees that there is considerable regularity in the curves. In the plots with many straight lines, one has to admit that there is no noise to be seen. The satellite data are apparently much more precise than that.

    Instead of noise, one sees evidence for processes that have not been acknowledged -- fast processes.

    About short-term vs long-term sensitivity, again, the straight lines in the plots are evidence that the process being measured for sensitivity reaches near-equlibrium in the time between points. Therefore the slope can be measured. The curly parts show no such equilibrium and if they are part of what you call climate sensitivity, then I have to agree with you. You need a long, long time -- maybe a century of data.

    But there is more than one process going on, you see.

    I am trying to quit, if the moderator will allow me the courtesy of exiting gracefully and not appearing to be slinking off into the shadows. Pretty please?
    Response:

    [DB] "I am trying to quit, if the moderator will allow me the courtesy of exiting gracefully and not appearing to be slinking off into the shadows. Pretty please?"

    Moderator baiting is not an endearing trait in any venue; desist.

    If you cannot handle the hard questions from knowledgeable persons then you should not posit what amounts to curve-fitting mathturbation/climastrology. From the inception of your comments on this thread you have offered up nothing of substance to support your assertions.

    Like Spencer, you serve up vacuous handwaving, smoke, mirrors and blustrous intimations of conspiracy to suppress the New Truth. You follow that up with failed, disingenuous threats of running away from requests for answers. Run then.

    Just stop wasting everyone's time.

  9. Ben: nothing I said should give you the idea that you understand the processes involved.

    Water vapour does not respond directly to changes in CO2. The response time of water vapour to temperature changes is not the issue - it is the response time between CO2 and the change in temperature that matters.

    You used audio feedback as an example earlier. If I record your voice and play it back at extreme volume a year later, and blow out the speakers, do you think the lack of feedback 5 seconds after you speak into the micropphone will prevent it?
  10. Moderator @58, don't tell him to run. I am still waiting for his response to my questions @39 given the supplemental information @43.

    Uncle Ben, like Spencer is wrong in so many areas it is difficult to pick a point of attack. But I believe the answers to my questions will show that even their most fundamental premise is simply false, and indeed was shown to be false by Spencer himself, though he chose not to notice.
    Response: [DB] Ben is welcome to continue to interact here, minus the histrionics. If he has anything substantive to prove, he will do so. Thus far his agenda has been assertion, intimation and misdirection.
  11. Uncle Ben - "After the storm of protest by those who wanted to do something different, he did publish results for all the models."

    Can you point to where this was published? I am unaware of any peer-reviewed response by Spencer to the Dessler and Trenberth papers.

    I am, on the other hand, aware of Wolfgang Wagner, Editor in Chief of Remote Sensing, resigning over the poor peer review, and unwarranted publicity and misstatements by the authors, of that Spencer paper.

    Please, if you have any pointers to a peer-reviewed Spencer response, I would love to see it!
  12. Rom 60

    I answered before, Tom, that is a strange plot. The lines are curved and vertical, and they are the majority of the segments. Without any more information about the circumstances under which the data were taken, I can only repeat that some single process is dominatig, and is characterized by hardly any sensitivity at all to any forcing by the independent variable dH/dt.

    The bowing out of the nearly vertical lines into slight curvature represents perhaps a forcing which is reversed by some negative feedback to keep the temperature more narrowly confined to a range than it would without it. But the dH/dt seems to affect dT very weakly. Something else must be going on. Will you provide more information?
  13. Rom 60

    Sorry. Should be Tom 60. It's late here.
  14. Uncle Ben @62, thankyou. Now it is time for me to place my cards on the table.

    All graphs I have presented on this thread (except for the satellite channel graph) have come from Spencer and Braswell, 2010. They have been figure 8d @31, figure 3a @57, and @39, figure 7d, presented below without modification:



    Figure 7d is the time connected phase space plot of dH/dt against t (as all three are), but of a model run where the net radiative feedback parameter (lambda) is 2.5, but the forcing is a low pass filtered series of random numbers.

    Neither Spencer (knowing what it is), nor you (not knowing) seem prepared to face the implications for his theory. Spencer practices creative avoidance, calling the pattern a "looping or spiral pattern". That is a poor description, however. The pattern clearly lacks the long nearly straight lines horizontally to match the vertical lines I drew attention to that you would expect in a looping or spiral pattern. You draw attention to the slight curvature of those lines, but the curvature is no greater than the lines you (and certainly Spencer) are prepared to call straight when they appear in figure 8d:



    In fact, what distinguishes this figures from the ones you are used two are two simple facts:

    1) The random fluctuations in forcing are large relative to the feedback parameter; and

    2) There is no overall trend in temperature with time, so that unlike in figure 8d, the pattern keeps tracing out in the same space rather than progressively moving to the right.

    In fact, in figure 8d the only two thing which were changed in the model from fig 7 to fig 8 were the significant increase in size of the feedback factor relative to the size of the random forcings (countering 1), and the addition of a steady time independent forcing which induced a positive temperature trend with time (countering 2).

    The key point here, however, is that the vertical nearly straight lines in figure 7d are directly analogous with the diagonal "striations" in figure 8d (and 3a). As such, according to your theory and Spencer's their slope should give the feedback parameter. Clearly it does not. In other words, at the very minimum, the claim that the slope of the diagonal striations give the feedback parameter does not hold true when random influences are large relative to the feedback parameter. In other words, in noisy conditions such as obtain in the real world, Spencer's analysis does not hold.

    And suggestions that it is just a mathematical fact that the slope gives the feedback factor are just empty bluster.
  15. Tom Curtis - Thank you, a wonderful illustration of finding what you're looking for, despite a lack of support in the data. And a good overview of what Spencer has attempted to do with these papers.
  16. Tom 64

    Thank you, Tom, for a most interesting exercise.

    I disagree with your bold print statement. The slope I saw in the plot I responded to is infinite, corresponding to sensitivity zero. And in the real data, it appears to me that conditions are not nearly as noisy as you think.

    But let us agree to disagree. Thank you for sticking to the science instead of the man. That does you credit.
  17. Uncle Ben, when you first began to post, I thought you were attempting to breathe life into the uncertainty monster. I see that's not the case, but I would suggest taking a closer look at Roy's apparent apotheosis. After all, the book and the arguments used in it have long since been taken apart both in the blogosphere (here at SkS and Barry Bickmore's lovingly titled "Just Put the Model Down, Roy") and in publication (e.g., Murphy & Forster 2010), and general (and generally eye-opening) critiques of Roy's work are all over the place. To his credit, Roy has responded to some of the criticisms, yet he has ignored others. When defenders of Spencer say things like "the first part is clear, something Spencer might have written," it just makes the hair on the back of my neck stand up.

    It sometimes seems to me that Roy, rather than being the usual type of politically-driven obfuscator, is on a personal quest with his climate science, a quest in search of the "perfect language" or the GUT, that simple equation that makes sense out of everything in the anthrocentric universe. Questers seek to confirm that the universe is constructed in such a way that humans (particularly individual humans) are perfectly (providentially?) suited to "figure it out." As I've probably walked over the edge of the Cliff of Moderation in a number of ways, I'll shut up now.

    One more thing: Tom, that was good stuff. I can explain many complex things, but as I came back to the thread yesterday, I tried to figure out a comprehensible way to explain what was intuitively obvious, and I just couldn't do it.
  18. I agree with KR and Uncle Ben - Excellent insights there, Tom Curtis.
    I'm a little bemused by Uncle Ben's reaction. Many of us here have used and taught something by way of data analysis and statistics - and anyone who has done tends to be very cautions of 'seeing' signals; and so use tools (analysis, simulations etc.) to ensure some objectivity results... this is a great illustration of the point.

    What does worry me, where Mitt Romney to get elected - this seems to be the perfect 'science' for an etch-a-sketch president...
  19. Tom Curtis#64:

    Well done, sir. Your clear presentation of these somewhat cryptic figures leaves us with little room to 'agree to disagree.'

    The point about the lower figure d's progressive drift to the right in response to long term forcing is worth emphasizing. It is clear that if you follow the curve from left to right, there's been an overall warming of some 0.5 degrees. But that's just a model run, the 'skeptics' say. Per Uncle Ben#66, "in the real data, it appears to me that conditions are not nearly as noisy..."

    Oddly enough, we can see what the real world looks like courtesy of this Sept 2009 blog post.


    -- sourced immediately above

    These data are Lower Troposphere (eliminating the TMT problem you identified above) and are averaged over a 3 month interval. The upper and lower trajectories in the circled 'cooling event' are on a much lower slope than the 6 (Watt/m^2)/degree line shown. Spencer describes this event as showing "a classic radiative forcing signature." Recalling that these slopes are inverse sensitivity, lower slope is higher sensitivity: Spencer's own analysis of the real data thus shows that sensitivity to radiative forcing is far greater than he has subsequently maintained.

    Similarly, the entire packet of data points fall on a lower slope (on the order of 1.5 (Watt/m^2)/degree by eyeball). This figure resembles the lower figure d you showed, which has a comparable overall slope of 1.3. Further, the 3 month averaging reveals that the low sensitivity 'slope=6' is based on transient, short-term noise.

    BTW, the magical slope=6 comes from Spencer 2007:

    Our measured sensitivity of total (SW + LW) cloud radiative forcing to tropospheric temperature is -6.1 W m^-2 K^-1.

    However, he concludes:

    While the time scales addressed here are short and not necessarily indicative of climate time scales, it must be remembered that all moist convective adjustment occurs on short time scales.

    That short-term (weather and seasonal) sensitivity is greater than long-term (climatic) sensitivity should be no surprise. Thus goes the Nobel Prize.
  20. Muoncounter @69, I find it interesting that Spencer used the more appropriate UAH LT channel in a blog post in 2009, but that by the time it came to publication, he was using the less TMT channel:



    The reason for the switch seems evident. Not only does the TMT data give more of a "striated" look", but it has more line segments that appear to match his magical slope of 6. The reason for that is that by switching from TLT to TMT, he has contracted the range of temperature variation from approximately 0.7 degrees C to 0.4 degrees C, and thereby increased the slope of all line segments.

    Despite reducing the temperature range, he has the gall to warn us that by using the TMT channel he has increased the temperature range, saying:

    "The midtropospheric temperature
    anomalies are somewhat magnified compared to the surface temperature anomalies, a fact which must be kept in mind if comparing feedback parameters computed relative to the different temperature measures."


    Based on models, it is expected that mid tropospheric temperatures will increase more rapidly than surface temperatures. But the TMT channel does not measure mid-tropospheric temperatures, but a weighted average of temperatures from the surface up into the stratosphere, and are not expected to increase more rapidly than surface temperatures. Even if Spencer had not been deeply involved in developing the TLT channel to compensate for this, he would have known it anyway simply by comparing the temperature scales of the two plots.

    More directly relevant to this discussion, however, is that most line segments in the plot do not have anything like the slope he so desires. This is not clear in the TMT plot because the mass of lines in the center conceals the detail. Therefore I have blown up a detail of that section so that you can judge the slope of the lines for yourself:



    Clearly the majority of the line segments are near vertical, which if interpreted literally based on Spencer'theory would indicate that no change in forcing could result in a change in temperature. Comforting news indeed, for it implies that whether the Sun snuff's out quietly, or goes Super Nova, the Earth's surface temperature will maintain a pleasing constancy.

    Uncle Ben rightly objected that such a finding would be ridiculous. What he has not shown is any reason why neither the near vertical lines nor the near horizontal lines indicate the climate feedback parameter (or the inverse of the climate sensitivity), but the carefully selected 5 or 6 segments that happen to match Spencer's pre-chosen slope do.

    In fact, the very assumption that some segments will reflect the climate feedback parameter uncontaminated by noise, while others will only reflect noise, seems absurd to me. Nature does not conveniently compartmentalize the year into periods when only the feedback parameter is influential, and periods when noise completely dominates. Yet that, essentially, is what Spencer's method assumes.
  21. (Late to party) @Uncle Ben, #3, regarding "3. The little model demonstrates a mathematical fact, which is already obvious to students of statistics, namely that you cannot compute the sensitivity to one variable if another hidden variable is varying the output": It's not a fact. In fact, it's false. The effect of "one variable" upon a response is in many systems separable from the effects of the others. In fact, this is often how "others" are identified. This is especially the case if the "one variable" is tied to the response using a physical model derived by experiment.
  22. Curiousd here. Interested in communicating these things to physics trained non climate scientists. To me, if I go to the Berkeley Earth website and use their "global land surface temperature plot 12 month moving average", I see a nice looking fit that ignores obvious volcano effects and is described as "logarithmic". If I take the temperatures from that graph, look up the CO2 concentrations of corresponding years, and plot delta T versus log to the base two of the CO2 concentration ratio I get an excellent straight line with a slope giving a climate sensitivity of 3 degrees C. So "clouds/shmouds"......Spencer is wrong and over the time span of the Berkeley Earth data the C.S. is 3 degrees centigrade. What is wrong with what I am doing? Or am I right? (I could show the result if I could figure out how to post a graph on this thread.)

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