Thursday, December 15, 2016

Current global temps compared with CMIP 5

A plot has been in circulation for some time from John Christy. It is a version of one that he showed at a US Senate hearing, and is discussed here.



I don't know if it was ever accurate, but it ends in 2013, so obviously needs updating. It's also woth showing the other surface datasets, and definitely not showing the troposphere record, which I don't think is honest. The CMIP data is for surface, not troposphere.

So I have made my own version, using CMIP 5 data from KNMI. I have used their averages for the RCP groups, and their collection of 106 model runs (one per model/RCP), which is shown in the background. The complete data and R code for the plot are in a zipfile here.



It's a very different picture. The observations, as expected, are far more volatile than the multi-model means, and the slope is somewhat less, but is far from out of range. And of course, recent warming actually takes observations above the mean. I have set the anomaly base for all curves to 1981-2010, the WMO recommendation.



69 comments:

  1. Nick: You can get some very interesting results by choice of baseline. 1951-1980, 1901-1930 and 1880-1900 will give you an illustration of the problem, which arises almost entirely from the uncertainty in homogenization of the SSTs.

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  2. Nick: Most likely this is an R novice error on my part, but when I try running the script it doesn't find the function "fo" on line 16. I expect I'm missing a relevant package, but which one? My R version is 2.15.1 if that's relevant.

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    1. Mark,
      Martin has the fix below; just shift the one line definition to near the top. I have updated the zip file.

      Delete
  3. Nick, there's a slight bug in your R script. The line "b2=substr(b,11,20)" is truncating some values which extend beyond char 20, e.g. the value -0.125122E-01 loses its exponent.

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  4. Mark, the function "fo" is defined further down the script, in the line "fo=function(v,a,b){x=v[,1];v[x>a&x<b,]}". Just move that up to the top, and it should run fine. To fix the bug I mention below, change the line "b2=substr(b,11,20)" to "b2=substr(b,11,nchar(b))".

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    1. Thanks Martin,
      I have updated the zip file, fixing placement of fo() and the truncation. I have also added the trend numbers to the legend.

      Delete
    2. Thanks Martin and Nick, I've got it working with those changes.

      Delete
  5. What are the RCP scenario trends per decade?

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    1. JCH,
      I have updated the image, which now shows those numbers (C/Cen) in the legend.

      Delete
    2. JCH, the multi-model mean (rcp 8.5) is 0.23 C/decade for the period 1979-2016.
      However, that is global SAT and not a fair comparison with the blended observational indices.
      With a blended CMIP 5 index (71% SST and 29 % land SAT) the trend is 0.20 C/decade.

      It is complicated to make a fully apples to apples comparison with e g Gistemp loti. One needs a variable sea-ice mask for every single model run, since the observational indices use SAT over sea ice.

      For a layman it is much easier to skip SAT over sea ice, and simply use the SST below the ice. This is actually the standard output from the model SST and ERSST.

      Here I have compared such a simplified GISS index vs the corresponding CMIP5 mean.

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    3. Thanks Olof and Nick... both very useful graphs. So were the CMIP model trends the likely source for the SPM forecast of 2.0 ℃ per decade for the first two decades of the 21st century?

      With GISS Nov now in at .95 ℃, even with a relatively cooler Dec, it looks like K.a.r.S.T.e.N's predicted 30-year trend at the end of 2016 of .18 ℃ plus some change is shaping up to be about right?

      Delete
  6. To Nicks °C century trends for the surfaces we could add
    JMA Globe: 1.321

    This low trend will be due to a very poor coverage of the Arctic regions I guess.

    But we could also add, for the satellite readings
    RSS4.0 TTT: 1.793

    Even today, when having a look at Christy's testimony
    HHRG-114-SY00-Wstate-ChristyJ-20160202.pdf

    I still get a little bit enraged due to this impertinent comparison of UAH satellite readings with those of these strange VIZ sondes, out of service since good a while at the time the testimony was published.

    The comparison not only ended in 2005 (see chart on page 3) but was above all referring to TMT instead of TLT!

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    1. Wrong origin! That's my lady's nickname :-)

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  7. Could you make a histogram of the trends of all the realizations and compare to to observed trends?

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    1. Yes, though I'm not sure if it would help much. What I am planning to do is to look at the residuals after subtracting the MMM. I've been arguing at WUWT about the recent paper by Meehl and Santer, where they argue that the IPO gets lost in MMM, and fitting an IPO oscillation to the earth gives a better fit. IOW, the residual looks like IPO. We shall see.

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    2. A cool app would let you scale the model output (or just the resulting trends) by the changing the forcings. Or scale the SST portion of the observations to better match SAT. Or remove the ENSO component from observations. All of this confounds the Model/Observation comparison.

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    3. That paper was just a method to get a desired result. They pre-selected a model which did resemble IPO and then added the convenient yet arbitrary model's "IPO" to the model mean and found it was a better fit. That method will could also be used to make random data a better fit. Do the same thing by matching AMO and it will improve the match too. It is mathematically certainty.

      I know you will not be that foolish. It will be interesting to see what you find.

      Delete
  8. Nick, troposphere record not honest? or maybe unrepresentative? Could you share a little more detail on what you think is wrong with it?

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    1. jf,
      The troposphere is just a different place. To say that "models agree the observations must be wrong" when the observations are of something different is misrepresentation.

      Delete
    2. Hi Nick,
      is this to say more that this use of the troposphere record is not honest? use not the record itself?

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    3. jf,
      It's like someone saying - look how wrong the Fed was in predicting US inflation, and then superimposing a plot of Japan. They are just different. And the fact that UAH shows a much lower trend than surface measures (which are comparable) whiffs of cherrypick.

      I'm not a great fan of UAH reliability, and I often draw attention to the difference between V5.6 and V6. But that isn't the issue here.

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    4. Its important to note that the UAH project is not being funded by NASA. Its now the equivalent to an academic hobbyhorse for Roy Spencer and there is nothing official about it any longer. So if anyone else took the raw satellite data and processed it, it would have the same validity as UAH.

      Delete
    5. "UAH project is not being funded by NASA"
      I think the UAH index is funded by NOAA. Although ironically, NOAA funds V5.6, which is why they still produce it. That may change when V6 has a published paper. The NOAA funding was why they had to release their code.

      Delete
    6. J Ferguson, the satellite "troposphere" record, TMT or TLT-layer, is a dishonest comparison with models because it blends troposphere with stratosphere, and the stratosphere cools much faster than expected by the models.

      WIth radiosonde data it is possible to do honest comparisons layer by layer
      One can't say that the troposphere is warming slower than in the models. The large observed stratosphere cooling trend might be a sign that the greenhouse effect is larger than expected by the models..

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    7. The 2010 review article linked below discusses all the problems involved in comparing radiosonde and satellite observations with models due to the large uncertainty in the radiosonde and satellite measurements. "Dishonest" - yes, although other adjectives also come to mind.

      http://www.arl.noaa.gov/documents/JournalPDFs/ThorneEtAl.WIREs2010.pdf

      Chubbs

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    8. Radiosonde data also provides measurements of stratospheric wind with very little uncertainty.

      Speaking of which, no one has ever been able to explain why the equatorial stratospheric winds reverse direction every approximately 2.3 to 2.4 years. This is the QBO which operates like clockwork but with some jitter. The AGW denier Richard Lindzen worked his entire career on this behavior and still failed on coming up with a model to reproduce the oscillation period.

      Its actually driven by a lunisolar forcing with that same exact period. Apparently no one ever could deduce this period because they apparently never analyzed the nonlinear combination of lunar and solar stimulation along the equator.

      http://contextearth.com/2016/11/21/presentation-at-agu-2016-on-december-12/

      Maybe we should drain the swamp of AGW deniers such as Lindzen, Curry, Spencer, Salby, and Pielke that work on atmospheric sciences?




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    9. Excellent, someone else realising that BOTH the sun and moon affect climate ! Trying to find one without the other has led to failing to convincingly detect either for decades. Something I pointed in 2013.

      https://climategrog.wordpress.com/2013/03/01/61/

      Don't know why you need to badmouth Curry, she co-authored a paper with BEST showing a 9.2+/-0.1y period common to Atlantic and N. Pacific. She also hosted an article of mine showing a similar periodicity in Atlantic cyclone energy and SST, with a footnote pointing out that a combination of solar and lunar periods produces a 59y harmonic beat.

      p1=9.1;p2=10.8;
      cos(2*pi*x/p1)+cos(2*pi*x/p2)


      https://judithcurry.com/2016/01/11/ace-in-the-hole/

      Your constant snark and name-calling detracts from the interesting work you have produced and makes you less credible. Try adopting a cooler, more rational attitude.

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    10. Unbelievable that a behavior as simple as the QBO goes unexplained for over 60 years. That's essentially equivalent to the discovery of alternating current and no one identifying the source.

      Yet it is entirely conceivable when one considers that Lindzen's pathology all along was to create a fringe science (as Isaac Held describes) and then pursuant to that "has made a career of being wrong in interesting ways about climate science" (as Ray Pierrehumbert puts it).

      There is no way that anyone will be able to model the equivalent stratosphere/troposphere equations of state without first reworking the fundamental pressure/velocity behaviors based on Laplace's tidal equations.

      The most recent papers still assert that the value of the QBO cyclic period is due to an emergent resonance that is sensitive to absolute pressure. That is as absurd as finding a 60 Hz hum in an electrical circuit and claiming that is due to an internal resonance instead of coming from an external AC power source.

      It's possible that Lindzen's pathology was that he was aspiring to greatness by claiming wondrous new physics instead of settling for the mundane. You see that quite often in physics -- finding a new type of phase transition is much preferred to explaining by basic Newtonian dynamics. Note the Nobel prize being awarded to Kosterlitz & Thouless and Haldane for their work in vortex/anti-vortex modeling of a phase transition. I am not claiming that QBO is anything similar to an anti-vortex boundary between two hemispheres that spin-off vortices, but I suppose I could do that and garner some interest.

      But, alas, LOL I didn't do that in my talk, preferring the mundane explanation of Laplace's tidal equations from 1776 and applying the moon as a forcing. How pedantic can one get!

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  9. There are many cheats in the first graph. For example using 1983 as start year and aligning there, the year of the largest El Nino. So all observations after 1983 lie below the honest observational line, neither in 1998 nor in 2016 the El Nino was as strong as in 1983.

    Apart form that there is the problem with the surface air temperature (SAT) observations over sea ice especially in the arctic. In the models SAT all know at all grid cells, also over the see ice. In the observations it's not.

    A good idea would be to compare zonal means, especially means that exclude the sea ice regions.
    It is possible to make such a comparization?

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    1. The temperature response to the volcano should be in both the CIMP models and the observations, the El Nino not.

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    2. Well if you prefer Nick's presentation you need to notice that models run too cool in the early period and too warm at then. This alignment splits the mismatch in the trends and makes it look less bad at then end. The two are equivalent in terms of the mismatch in total warming, which is far too strong in the models.

      Which alignment you prefer will depend upon whether you wish to highlight this problem or minimise it.

      Greg

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  10. As Steve McIntyre pointed out, Gavin Schmidt produced his own version of the Christy graph shown in Nick's post and it showed essentially the same thing with regard to trends as Christy's original. Steve's post on baselining is informative I think. The real question is about the trends. Kudos to Nick for putting those numbers on his chart.

    https://climateaudit.org/2016/04/19/gavin-schmidt-and-reference-period-trickery/

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    1. The real question is how much energy is accumulating in the earth system. Why would Nick need kudos? The year is going to finish with a 30-year trend close to .18 ℃ per decade, and this after 18 years of about the best natural variation of the cooling variety is capable doing... almost nothing.

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    2. Hey Young, nobody really cares about that crap. All that matters is that Richard Lindzen never figured out that the fundamental behavior of the equatorial stratospheric QBO was governed by a lunisolar forcing. The guy spent well over 40 years pushing his insane theories and has essentially halted progress in the field of atmospheric sciences via his belligerent attitude.

      http://contextearth.com/2016/12/20/qbo-split-training/

      Time to drain the swamp of these useless atmospheric scientists such as Lindzen, Curry, Christy. They never added any fundamental understanding in the first place, so you really expect them to make any sense with respect to their ideas concerning AGW?

      Look at what Olof R said above! They have no clue how to separate the troposphere and the stratosphere, and "they" are the AGW deniers that are the nuts behind the wheel!

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    3. David,
      I see that I'm using the IPCC baseline. Of course SM was talking about a tropical troposphere plot, not global surface. I think there is merit in the Schmidt objection. The plot is not a race. No one fired a starting gun in 1979; well, they launched a satellite, but that did not affect the thing observed. So it does rather artificially emphasise the disparity, especially if the starting point was already untypical. Suppose they really did have the same trend, but started at a point of unusual separation, due to fluctuation. Then that separation would be preserved; the plots would never come into alignment.

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    4. With the satellite record now at ~36 years, would it be possible in a meaningful way for somebody to extend the record back in time? If it could be done, I think the result would be very interesting.

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  11. The science of the stratosphere and to what extent the stratosphere and troposphere interact were largely based on the models of Lindzen. And Lindzen has been proven wrong time and time again. Pierrehumbert has the guts to call Lindzen on his junk science, but why doesn't anybody else?
    quote

    Drain the swamp and redo all the atmospheric science from first principles. That's what I am doing -- starting from the fundamentals. Only then can one start making sense of this stuff.

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    1. So if you've got some good science to show, kudos, let's get on with it and stop bitching about Lindzen who is retired now anyway.

      You seem to get more satisfaction from deriding others than presenting your own work. Rather immature attitude.

      Delete
    2. "Anonymous December 30, 2016 at 5:28 PM
      So if you've got some good science to show, kudos, let's get on with it and stop bitching about Lindzen who is retired now anyway.

      You seem to get more satisfaction from deriding others than presenting your own work. Rather immature attitude. "


      I did present the results! To an audience of about a hundred scientists at the AGU conference earlier this month. I presented my own work, and wouldn't you know it, I mentioned that this research contradicted Lindzen's work and I did not get booed off the stage.

      Apparently you do not realize that for a new model to get accepted, then the original model (Lindzen) needs to be invalidated. Unfortunately, that's not the easiest thing to do, but it can help if the original research was suspect from the start.

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    3. Anonymous said "stop bitching about Lindzen who is retired now anyway"

      Yet I ran across this article from today:

      http://www.realclearinvestigations.com/articles/2016/12/31/skeptical_climate_scientists_coming_in_from_the_cold.html

      Richard Lindzen, the Alfred P. Sloan Professor of Meteorology at MIT and a member of the National Academy of Sciences who has long questioned climate change orthodoxy, is skeptical that a sunnier outlook is upon us.

      “I actually doubt that,” he said. Even if some of the roughly $2.5 billion in taxpayer dollars currently spent on climate research across 13 different federal agencies now shifts to scientists less invested in the calamitous narrative, Lindzen believes groupthink has so corrupted the field that funding should be sharply curtailed rather than redirected.

      “They should probably cut the funding by 80 to 90 percent until the field cleans up,” he said. “Climate science has been set back two generations, and they have destroyed its intellectual foundations.”


      Amazing the psychological projection of the rather "retiring" Lindzen. It may actually be Lindzen that has set back generations of atmospheric science research with his deeply flawed model of stratospheric winds (see QBO). He missed a very simple derivation back in the 1960’s that could have set a nice “intellectual foundation” for the next 40+ years. It's usually the case that the one that "doth protest too much" is the guilty party.

      As Atrios used to say, just documenting the atrocities.

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    4. Lindzen is still pumping out nonsense for his audience

      https://www.prageru.com/courses/environmental-science/climate-change-what-do-scientists-say

      https://scholar.google.com/scholar?as_ylo=2012&q=author:rs+author:lindzen&hl=en&as_sdt=0,27

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    5. cce, I looked at the prager u video and didn't see anything there that is scientifically controversial. Just Lindzen's opinions which fit well within the scientific consensus. Trashing other's work in broad and meaningless terms doesn't help anyone really.

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    6. David, so do you think Lindzen's claim of a Climate Sensitivity of 0.5 degrees C is "within consensus"? If so you have a very weird view of the consensus.

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    7. billh, Of course that paper is wrong as recent observations have shown. I don't think Lindzen himself has recently defended it. In the video I saw he doesn't get into that level of detail even though he acknowledges the 1.8 degree F. GMST increase that the data shows.

      Delete
    8. David Young January 1, 2017 at 5:10 AM
      "cce, I looked at the prager u video and didn't see anything there that is scientifically controversial. Just Lindzen's opinions which fit well within the scientific consensus. Trashing other's work in broad and meaningless terms doesn't help anyone really."


      Young has no sense of Lindzen's history when it comes to trying to understand atmospheric flow starting in the early 1960's. He likely wasted everyone's time with his fringe scientific theories.

      Furthermore, Young is the guy that is ranting about the fact that the fluid dynamics is being done wrong, yet he can't face the fact that Lindzen is likely responsible for the current state of the research.

      It's really not that difficult to solve the equations of flow at the equator.

      http://contextearth.com/2016/12/31/lindzen-doth-protest-too-much/

      And Nucitelli says Lindzen is "the man who's probably been the most consistently wrong climate scientist in history"

      https://twitter.com/dana1981/status/815313104263184385

      The growing consensus is that Lindzen has been wrong on everything.



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    9. I'm not sure anyone is "wrong on everything" except in the minds of those on the fringes of mental stability.

      In any case, something I thought Nick might want to comment on I came across elsewhere. It seemed a rather detailed exposition on the subject of climate sensitivity and reconciling this response with the observations discussed in this post by Nick.

      https://niclewis.files.wordpress.com/2016/03/briefing-note-on-climate-sensitivity-etc_nic-lewis_mar2016.pdf

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    10. Working Group I: The Scientific Basis


      Executive Summary

      ...

      Improve methods to quantify uncertainties of climate projections and scenarios, including development and exploration of long-term ensemble simulations using complex models. The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible. Rather the focus must be upon the prediction of the probability distribution of the system's future possible states by the generation of ensembles of model solutions. Addressing adequately the statistical nature of climate is computationally intensive and requires the application of new methods of model diagnosis, but such statistical information is essential. ...



      He emphasizes the words I've put in bold print, but makes no mention of the rest of the paragraph (a ploy I've seen several times in comments on Climate Etc.)

      Is that being honest?

      Delete
    11. ...the long-term prediction of future climate states is not possible. ...

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    12. JCH, I'm not sure its a misrepresentation given the other points Nic makes.

      But how about the other points later on about specifying SST's and its effect on the MET office model or the point about tropical convection and clouds? These are important questions I think.

      I've always wondered about the lapse rate theory because convection is an ill-posed problem. And in GCM's its highly parameterized.

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    13. David Young - I was referring to Lindzen's Prager University video.

      As for low climate sensitivity, I don't buy it. Remember when there had been no warming for 18 years?

      18-year trend - .02 ℃ per year
      12-year trend - .023 ℃ per year
      8-year trend - .044 ℃ per year
      5-year trend - .095 ℃ per year


      See if you can find those sorts of warming rates in Nick's trend gizmo.

      From a very important paper:

      The synthetic series in Fig. 5a also show examples of greatly accelerated warming lasting a decade or more, which are evidently spring-back effects as an internal variability cooling episode is followed by a strong internal variability warming episode. The strong warming episodes are further amplified by the underlying forced warming trend. One extreme example shows a warming of almost 1 °C in 15 years—a much greater 15-year warming rate than has occurred in the observations to date (red curves). These spring-back warmings illustrate another important potential consequence of strong internal multidecadal variability as simulated in CM3, and reinforce the need to better understand whether such internal variability actually occurs in the real world.

      Delete
    14. As observations accumulate and time passes, it will become easier to distinguish "noise" from the "signal."

      Do you have any reaction to Lewis' observations?

      Delete
    15. It would be an honest video if it was titled "What scientists named Richard Lindzen believe as seen through his ideological keyhole."

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    16. David Young: "of course that paper is wrong".

      It's rather more than one paper, David. Lindzen has been pursuing his low climate sensitvity theory since 1990. So I take it you agree with the proposition that he's been wrong for the last quarter of a century. Your suggestion,on the basis of Lindzen's recent silence on the subject,that he agrees with this as well is undermined by the fact that, in the Prageru video, Lindzen uses his lifetime publication record as the main reason as to why we should take him seriously on the subject of climate change.

      Delete
    17. Lindzen has been wrong on low climate sensitivity, the iris theory, and QBO. Close to a Thomas Gold in wrongness, who thought the lunar lander would sink into the dust, believed in abiotic oil, and a steady state theory of the universe.

      People like Gold and Lindzen have fringe views for whatever reason. On Lindzen's Wikipedia page, it mentions that his graduate students state that he has a "deep contrarian streak". That matches well with Trump's world view, who wants to "drain the swamp" of DC, while Lindzen wants to do it with science.

      I think Lindzen is the swamp-dweller.

      Delete
    18. David Young,
      Nic Lewis persists in calculating climate sensitivity for the Hadcrut4 index, not for global SAT like the models.
      If one compares the climate sensitivity of models and observations "apples-to-apples" they are quite similar:
      https://www.climate-lab-book.ac.uk/2016/reconciling-estimates-of-climate-sensitivity/

      Delete
    19. From the Lewis document to which DY linked:

      36.
      Finally, I will briefly mention the
      hiatus...

      AR5 goes on to state that it is more likely than not that internal climate variability in the near term will enhance and not counteract the surface warming expected to arise from the increasing anthropogenic forcing.
      I disagree (ignoring ENSO and similar short term variability). ...


      So Lewis disagrees. And that's the end of it because they are right and he's wrong, imo. Lewis is a card carrying member of the Church of the AMO, as is Professor Curry.

      More Lewis:

      37. The AMO, which a majority of climate scientists appear to accept is a natural quasi-periodic oscillation with a typical period of 60
      - 70 years, is known to affect GMST and was in an upswing phase from the mid 1970s to the mid 2000s.


      You like the replication crisis. Well, replicate the studies that showed the AMO caused part of the warming from the mid 1970s to the mid 2000s. You'll have a basic problem with replication. There ain't no studies that have demonstrated the AMO caused any of the warming that occurred from the mid 1970s to the mid 2000s. From what I can tell, there are a bunch of "this line of wiggles looks like it might have caused this line of wiggles" studies.

      So you're a really smart guy David Young. I'm just a cowboy... a C+ student. Show me how - as in: how the road gear makes my tractor go fast - the progressively warming SST from the mid 1970s to the mid 2000s of the tiny North Atlantic both overcame the progressive cooling of the Eastern Pacific - a big-ass area - from the mid 1980s to 2013... and raised the GMST of the earth.

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    20. JCH, I don't know about or care about the hiatus. What I found interesting about Lewis' writeup are some of the observations about GCM related to SST specification and tropical convection. I also noticed that Held has a new post on different versions of the GFDL model.

      Delete
    21. The pattern that I see here is that Nic Lewis always responds to things like the blog post Olaf referenced above. In this case, there is a very long response at Climate Audit. Nic commented on Hawkin's blog and invited people to comment and correct any problems in his response. The original authors could easily have responded. They chose not to comment at Climate Audit or so far as I can tell anywhere else.

      This highlights two problems.
      1. Our data is sufficiently inaccurate and TCR is sufficiently sensitive to the data trends that there are pretty large uncertainties.
      2. There is often a disconnect when scientists are challenged on the details of their work. It's happened in my experience many, many times. I think I know why this is the case and believe it has to do with the academic and scientific reward system, which rewards a high volume of lower quality publications over fewer but higher quality publications. BTW, JCH, it would be nice along these lines for Lindzen to correct the record with regard to his ECS paper too.

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    22. Nic Lewis does the most mundane pedantic analysis that desperately tries to obscure the fact that there is something called the EFFECTIVE CO2 TCR -- which is what really matters.

      Boring = Effective TCR is ~2C and ECS is ~3C, which you can estimate by looking at land-only. Its been estimated as such since the Charney report in 1979 and the latest El Nino hasn't changed its value.

      Delete
    23. David Young,

      The authors did respond to Nic Lewis at Hawkin's blog. His challenges don't check out and were easily batted away. There is no doubt that the HadCRUT4 method and coverage applied to CMIP5 models produces substantially reduced warming compared to the true model SAT trend. There is also little doubt that the HadCRUT4 method and coverage has underestimated historical global surface-air temperature change, no matter how much resistance there is to recognising this in certain quarters.

      Our data is sufficiently inaccurate and TCR is sufficiently sensitive to the data trends that there are pretty large uncertainties.

      Yes, I think the indications are that energy balance methods looking at historical warming don't provide a useful constraint on future warming, for a number of reasons. They can perhaps be taken as further indication of a most likely 2-4K range.

      Delete
  12. The average trends in Fig.2 are approximately the same for RCP 26 to RCP85 . There seems to be no correlation between emission of green house gases and temperature. My guess: (a) The differences in atmospheric CO2 - concentration are small for the different scenarios considered in the time interval 1981-2010. (b) retardation

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    1. "The differences in atmospheric CO2 - concentration are small for the different scenarios considered in the time interval 1981-2010."
      I would expect they are using the same forcings for each scenario, as long as the history is known, which is basically for the duration shown here, with just a few years of scenario use at the end. So the differences in the graph are mainly due to the chance variation of models in each sample.

      Delete
  13. Question for you Nick. I seem to remember someone saying that aerosol forcing was an emergent property of the sub grid models in GCM's. Do you know the details of this? I'm interested because it seems that aerosol forcing is pretty important to correctly evaluating energy balances.

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    1. Do you know who really screwed up atmospheric science research for a generation? Richard Lindzen, that's who. He could have associated lunisolar forcing with Laplace's tidal equations over 40 years ago and laid a proper foundation for modeling all the global atmospheric circulation patterns henceforth. Yet, instead he created a bizarre theory that has waylaid unsuspecting researchers since.

      Scientists such as Ray Pierrehumbert have been on to him, e.g. "It's okay to be wrong, and [Lindzen] is a smart person, but most people don't really understand that one way of using your intelligence is to spin ever more clever ways of deceiving yourself, ever more clever ways of being wrong. And that's okay because if you are wrong in an interesting way that advances the science, I think it's great to be wrong, and he has made a career of being wrong in interesting ways about climate science."

      This is how you do QBO modeling correctly
      http://contextearth.com/2016/11/21/presentation-at-agu-2016-on-december-12/

      Please, let's start by draining the swamp of these cleverer-than-thou scientists such as Lindzen. He has always been wrong about everything, starting from his work in the 1960s.

      Delete
    2. Web,
      It's a reasonable question, and I don't think a rant about Lindzen and QBO is the answer. More helpful, I think, is looking at 9.4.6 of the AR5. I'll be away for a few hours, but hope to have more to say on that then.

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    3. And you have Isaac Held, who says that he had studied under Lindzen and found him smart but highly contrarian and a fringe scientist.

      “There’re people like [Lindzen] in every field of science. There are always people in the fringes. They’re attracted to the fringe . . . It may be as simple as, how do you prove you’re smarter than everyone else? You don’t do that by being part of the consensus,” Held says.

      All of Lindzen's theories are garbage and scientists such as Held are having a devil of a time trying to reconcile all of the follow-on work with the simple "fruit-fly" models that contradict it.

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    4. Mine is not much of a rant when you consider what nasty things Pierrehumbert and Held have said about Lindzen, as those guys are considered established climate scientists. Moreover, Held wants to do "fruit fly" science which is essentially described in this geophysical fluid dynamics review piece by Vallis.

      Everything in fruit-fly science starts with the most fundamental behavior observable, which in this case is the QBO. Temperature and wind velocity are connected, but first one has to understand the cyclic dynamics of QBO. You won't find anyone that has a real clue as to why that has a fixed period, and that all began on the wrong foot with Lindzen's botched theory. You can put lipstick on a pig, but it's still a pig.

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