Climate Audit

NokTang

“I didn’t pay much attention to this paper (hereafter referred to as LC) when it came out”
* Why not? Lindzen and Choi are prominent climate scientists. Was it because of the “end of the AGW scam” that urged you to rebuke this paper in order to reinstall the status quo?

Anywayz the LC09 paper has been rebuked already wideley in the sceptic camp where, unless in the Church of Climate, there’s no place for group thinking.

http://motls.blogspot.com/2009/11/spencer-on-lindzen-choi.html
http://www.drroyspencer.com/2009/11/some-comments-on-the-lindzen-and-choi-2009-feedback-study/

James Chamberlain

Judith,

I appreaciate your answer and tone. I hope that more climate scientists take your route in defending themselves.

James

• Judith Curry
  Posted Jan 18, 2010 at 3:54 PM | Permalink

  Thank you James!

Paul

re: http://www.gewex.org/reports/workshop02.pdf

It would appear that no one in the climate community can evaluate and compare modelled climate sensitivity to observations. At best modelled climate sensitivities are a guesstimate.

Summary: No confidence in the models.

It is a pretty fix that both empirical and modelled approaches are beyond our ken.

Luboš Motl

Dear Judith,

thanks for your detailed analysis. Is it OK to admit that a majority of it is a (somewhat cherry-picked) review of critical points that have usually appeared elsewhere?

http://motls.blogspot.com/2010/01/ipcc-types-read-lindzen-choi-2009.html

I have seen a newer version of the Lindzen-Choi paper and pretty much all the things I was dissatisfied with – or convinced by others to be dissatisfied with – have been fixed, as far as I can say.

However, you seem to believe that there exists a deeper path of criticism of the very basic framework by LC. The most far-reaching point in this approach of yours is the following sentence:

“The basic assumptions behind this type of sensitivity analysis based on top of atmosphere fluxes used by LC need to be tested by climate models.”

I don’t understand the logic here. One can’t say that the LC theoretical model – which is just about the framework of quantities to be tested and their conjectured relationships – is falsified just by showing that the existing climate models don’t reproduce its assumptions, can he? Quite on the contrary, the logic here is that the disagreement between LC and the climate models shows that that climate models are wrong – as long as one compares the models results with the empirical data. The objects that LC are calculating are really phenomenological ones – they can be defined operationally from the empirical data, in a simple way. Whatever the theories and models are, they must be able to calculate the corresponding quantities because they’re measurable.

One can’t “debunk” a criticism (or falsification) of models by assuming that the models are correct, can he?

I have clearly had different zeroth-order expectations about the dependence of the radiation on the temperature etc. than Richard had. I always imagine that the black body radiation is the bulk of it and all the other effects including the albedo are perturbations.

But Richard knows quite something about the climate and his and Choi’s test is a very clever challenge – a method to isolate the sensitivity that reveals many other patterns and data that the models should agree with. I am surprised that you disagree with this modest general proposition.

Another point. You say that the radiation is not determined just by the sea surface temperature but also by the vertical profile of the temperature and humidity, among other things. And I fully agree. But that doesn’t mean that one can’t get anything interesting by neglecting these extra things.

The idea is that all these other factors behave “randomly”, according to some statistical distribution. The vertical gradient of temperature at a certain altitude and the humidity over there are random variables that are – in the tropics – distributed in some way.

The point is that if you neglect their influence on the energy flux, you will just add some noise to the LC curves. Indeed, that’s a part of the noise that is shown in the Lindzen-Choi graphs. But as long as the slopes in the graphs can be determined at some appropriate level of statistical significance – both in the models and in the empirical observations – it just means that the noise, including the non-temperature influences on the energy flux, has simply averaged out, right?

Cleverly, LC obviously look at the time intervals where the changes have been fastest because these are the best points to suppress the noise. But the vertical humidity profiles etc. change the time-derivative of the fluxes in some way, and the mean value of this change is how the atmosphere works “normally”. The average influence of the humidity profile is a part of the question, and it’s completely correct that it is a part of the question. LC study the actual climate system which does include humidity and its vertical profiles and their fluctuations in time. They want to determine the sensitivity in this real climate. So they look at the corresponding empirical, observed data – and they try to adjust parameters in a phenomenological model that most accurately reproduces these observed data. This is a clearly valid methodology.

When it comes to CO2, this logic of averaging the “noise” out is applied all the time. All temporary and local changes are just “irrelevant weather” effects while what we get by average over the globe and 3 decades is the “important CO2 climate signal”.

Sorry to say but the fact that the sea temperature decides about the energy flux above it is much more solid – and much more “dominant an influence” – than the influence of CO2 on the temperatures. So if the methodology of “treating all other effects as noise that is supposed to average out, to isolate the signal” can be applied to CO2, it can surely be applied to the sea surface temperature.

I think that the original paper by Lindzen and Choi had mistakes but in general, it is a clever new way to isolate some “parts of the climate device” that can be separately measured and separately compared to the theories and models. This is exactly how science should be done. One must look at the reality from new angles – and find the new best observables that allow us to decide about the agreement or disagreement between the reality and the theories most efficiently and accurately. This is much better than to compare – and test – just some incomprehensible overall mixture of millions of influences that haven’t been verified in isolation. It’s much better than to use still the same test – that has been “programmed” to pass because it’s the only thing that the climate models have been trained to pass. Such a single test doesn’t prove any validity.

Many more tests are needed and they have to be done all the time. One has to study dependences of many pairs of quantities on one another, the critical exponents in temporal and spatial autocorrelation, the dependence of fluctuations and various correlations between fluctuations on the time scales, seasons, latitude, altitude – everything.

Too bad you disagree. I feel that the criticism – an eclectic synthesis of critical points found at various places – is primarily an excuse for not learning new ways how to look at the climate system (perhaps because of fear that it could reveal that something you have believed is incorrect). But the new way by Lindzen and Choi is certainly worth considering.

Best wishes
Lubos

• Judith Curry
  Posted Jan 18, 2010 at 4:19 PM | Permalink

  Lubos, thanks for your thoughtful message, and for pointing out your recent post on LC. With regards to the model they use, it is based on a simple energy balance climate model and radiative convective model (that have been around for decades). A simple feedback analysis of the simple energy balance climate model was first done I think by Jim Hansen and MIchael Schlesinger in the 1970’s. This kind of model tied to the TOA radiation fluxes doesn’t make any sense for a region that is sub global (such as what LC did); to apply this would require a transport term to account for advection into and out of the region.

  So there is nothing novel about the model that LC used, but the model (at least in the form they use) should only be applied globally and not to a region. And if people believed the simple energy balance and radiative convective climate models, we wouldn’t need global general circulation climate models. These simple models are useful conceptual tools, but are not convincing to me in terms of providing a useful estimate of climate sensitivity when applied in the manner of LC

  • Artifex
    Posted Jan 18, 2010 at 8:45 PM | Permalink

    I buy Dr. Curry’s point about the transport term needing to be considered and the correctness of LC may very well depend on the magnitude of this flux. However if this flux is very small compared to the incoming and outgoing energy LC may still hold. Does Dr Curry have a guess at the magnitude of this term ?

    There is another interesting point here. It would seem to me that if there are big arguments over the size of the transport term,the existing GCM’s could be used to provide estimates of the transport term. Then if the LC model still points to a dramatically lower sensitivity, what does that say about the GCM’s ?

  • Wondering Aloud
    Posted Jan 19, 2010 at 11:18 AM | Permalink

    As an often hard line trouble maker I want to change my usual approach and thank you Judith for your efforts and thoughtfulness. this is the kind of discussion I like. I hate the tendancy, mine as much as anyones to be knee jerk and pick sides all the time.

• EdeF
  Posted Jan 18, 2010 at 5:53 PM | Permalink

  After reading LC2009 and the critique and the response from Lubos, I have to concur with Lubos. BTW, here is the link to the ERBE experiment:

  http://asd-www.larc.nasa.gov/erbe/ASDerbe.html

• Dave
  Posted Jan 19, 2010 at 9:29 AM | Permalink

  Maybe I’m showing my ignorance here, since Dr Curry hasn’t picked up on these points, but:

  “The idea is that all these other factors behave “randomly”, according to some statistical distribution. ”

  Surely, if you assume that, and your results diverge from reality, you have proven, reductio ad absurdem, that they are not random? Or, you can only have as much confidence in them as in your initial assumption.

  “One can’t “debunk” a criticism (or falsification) of models by assuming that the models are correct, can he?”

  Of course you can. If you assume something to be true, and it leads to completely nonsensical conclusions, you can say with some confidence that the assumption is wrong.

  “as long as the slopes in the graphs can be determined at some appropriate level of statistical significance – both in the models and in the empirical observations – it just means that the noise, including the non-temperature influences on the energy flux, has simply averaged out, right? ”

  This seems totally bizarre to me. You seem to be contending (reasonably) that a trend may be made up of signal+noise, but *assuming* (unreasonably?) that the part you are looking at is the signal and not the noise.

• Gerald Browning
  Posted Jan 20, 2010 at 12:46 AM | Permalink

  Lubos,

  I enjoyed your objective review of the LC manuscript. I look forward to reading their new manuscript.

  Jerry

Carl Gullans

PaulM: Could have pointed it out w/o being snippy; don’t we all want Judith to have a conversation here? No need to be rude.

• PaulM
  Posted Jan 19, 2010 at 12:37 PM | Permalink

  I don’t think I was rude. I just pointed out an error rather briefly, expanded on by Terry above. Indeed it is to be welcomed that JC posts here and responds to comments. I am sure she is aware that anyone posting on a climate blog needs a thick skin. Yes she deserves some respect, but so do L&C. She should acknowledge her mistake.

Mike B.

Judith,

I don’t understand why you are so critical of the fact that LC only looks at the sensitivity in tropics. LC makes it quite clear, throughout the paper, that they have focused only on the tropics. They also explain why they looked only at oceans (satellite data was unreliable, and in any case land area represents only22% of the tropics).

This criticism is particularly strange when you later note that you yourself have in the past conducted studies focused on the Arctic. Less than 4% of the earth’s surface is above the arctic circle, while about 35% is between 20% North and South.

Finally, I don’t think LC’s “neutral” comment regarding the extratropics means what you imply.

• Judith Curry
  Posted Jan 18, 2010 at 3:53 PM | Permalink

  Mike, thanks for your question. I am not critical of them focusing on the tropics, but rather for inferring global sensitivity from analysis of the tropics

  • Ron Cram
    Posted Jan 18, 2010 at 5:31 PM | Permalink

    Judith,
    I thought LC was inferring radiative imbalance in the tropics. Is that not correct? Wouldn’t radiative imbalance in the tropics be a fairly decent proxy for global climate sensitivity?

    • Ron Cram
      Posted Jan 18, 2010 at 5:37 PM | Permalink

      Judith,
      I see you now that you had already answered my question when you answered Motl’s. Thank you.

    • Judith Curry
      Posted Jan 18, 2010 at 6:40 PM | Permalink

      Ron, part of the issue is that LC’s model should be applied globally, not regionally

    • WillR
      Posted Jan 18, 2010 at 6:56 PM | Permalink

      Re: Judith Curry (Jan 18 18:40),

      I need to read everything again — I just skimmed it — however…

      A fellow (Gene” gave this reply one day in a short discussion about modeling… (not here)

      I recall one instance when I wanted the modelers to run a specific type of prediction, which they refused because they said we can’t get the right answer. I tried to tell them that I knew that, but I only want to know:

      “What are the important variables.”

      So I have to ask the same question. What was the the intent of LC — to model the earth? Or to get an indication of the “the important variables”.

      I am used to doing large models — NP problems / time series. But I though he had a good point. It’s nice to know what’s important in the model — and where it’s important.

      So I have no trouble accepting their idea of a limited model.

commieBob

Hi Judith,

In Electronics (my field) we prefer to deal with systems, as much as possible, as black boxes. The response of a black box is most easily characterized by applying an impulse or a step input and looking at the output as a function of time.

The advantage of the above approach is that it doesn’t matter how the system is actually realized. For instance, one could have an analog box and a digital box and the system function would be the same. You couldn’t tell the difference between the boxes and you wouldn’t care anyway. All you care about is the function.

The reason I like LC is that it looks like a reasonable test of the (very very complex) black box that is the planet Earth. LC considers energy in at the top of the atmosphere and energy out as radiated from the surface but received above the atmosphere; in other words, energy in vs. energy out.

If you don’t like LC, can you perhaps suggest a better test? Do remember, though, that if you start worrying about the physical processes involved within the system, you probably don’t have a valid black box.

• Judith Curry
  Posted Jan 18, 2010 at 4:23 PM | Permalink

  commiebob, your point is interesting. The energy balance climate models assume a black box that is in equilibrium. Unfortunately the earth’s climate is never in equilibrium. Averaging over an ideally long time scale might get around this problem, but for the length of the data record that we have to work with, this isn’t very feasible. Given this, personally i think we need to dig into the processes and make sure that they are all treated correctly in the climate models and that they interact correctly.

  • P Gosselin
    Posted Jan 19, 2010 at 4:48 AM | Permalink

    “The energy balance climate models assume a black box that is in equilibrium. Unfortunately the earth’s climate is never in equilibrium.”
    No, the black box is not in equilibrium. You apply an input, and then you get a corrsponding output. In engineering mechanics, a bridge designer starts with free body diagrams, where all the relatively minor imperfections, anomalies and internal factors are neglected, not unlike a black box. It works very well and is a great place to start in the complex analysis of how the system will behave under different loads. I think this is analogous to what LC have done. It’s a good way to start. They’re on the right track.
    I could never imagine a bridge engineer starting a sturctural analysis by examining the weights of the rivets and the paint on the structure.
    A crude analogy, I admit.

• Bernie
  Posted Jan 18, 2010 at 5:09 PM | Permalink

  commieBob:
  I assume that you are not looking at any old set of black boxes. There is presumably a set of criteria for choosing a “reasonable” black box beyond simply the input/output parameters to begin with – hence Dr Curry’s approach makes sense because we already strongly suspect aht many of the processes inside the black box are poorly specified. The problem is that the level of investment in the models is very large.

  Where I think your analogy has some real power is the notion that it is meaningful to assess the value of the black GCM boxes by averaging across all the black GCM boxes. I know of no hardware designer who would ever dream of such a strategy to suggest that the “right” design must be among the black boxes because we get the answer we are looking for!!

  • commieBob
    Posted Jan 18, 2010 at 8:44 PM | Permalink

    Hi Bernie,

    Given my druthers, I would deal with only one black box at a time. What I was referring to as reasonable was the choice of input and output. Energy in, energy out, sea temperature.

    The black box, as I refer to it here, is physical. This black box is not an analytical technique, it is that which is to be analyzed.

    • Chris BC
      Posted Jan 19, 2010 at 1:13 AM | Permalink

      I also have experience in Electronics and testing and I’m with commieBoB (although I hope he’s not really a commie). It seems to me that it will be very difficult to convince everyone until the black box response can be measured adequately. Inputs vs. outputs.

      Whether LC have it exactly right, they’ve got the right idea. I have zero confidence in GCMs that aren’t even agreed upon by the warmists, and certainly not the skeptics. When NASA/NOAA and the Met Office can start making reasonably accurate 3, 6, 12, and 24 month forecasts then maybe I’ll believe they have enough understanding of what’s going on inside the box to model it accurately.

• Judith Curry
  Posted Jan 18, 2010 at 6:16 PM | Permalink

  commiebob, a question for you. Would you expect a complex nonlinear system (like the climate) to be treatable by a simple linear feedback analysis? What is the scope of system complexity that you try to analyze using control theory?

  • mpaul
    Posted Jan 18, 2010 at 7:04 PM | Permalink

    Much work has been done to apply stochastic process theory to black-box simulation. The method has been applied to moderately complex systems with great success.

    By contrast, deterministic computer modeling generally fails (and quite spectacularly) when the number of variables becomes moderately large. So perhaps the question is best directed back to you: what is the scope of system complexity that you think deterministic computer models can be applied to? Computational fluid dynamic models can not reliably predict air flow through a city (for example), so why do we think a deterministic model can be created for the climate (a much more complex system).

    • Calvin Ball
      Posted Jan 18, 2010 at 11:07 PM | Permalink

      Lucia said it very well once. We can model the air flow around an airplane quite well, as long as its going forward. Turn the airplane sideways, the modeling doesn’t work any more.

    • bender
      Posted Jan 18, 2010 at 11:36 PM | Permalink

      The standard counter argument is that at a certain time-scale the “stochastics” (i.e. determinstic nonperidic flow) are irrelevant compared to the deterministic forcings. This is a logical argument. That doesn’t mean it’s true, however. Read everything Tom Vonk has written at CA.

    • Steven Mosher
      Posted Jan 18, 2010 at 11:46 PM | Permalink

      I tried I honestly tried. needs pictures Vonk does. ( sorry star wars marathon is on )

    • bender
      Posted Jan 18, 2010 at 11:49 PM | Permalink

      When you read Vonk, do the raspy Vader voice. Eerie. Like jeez doing Cousteau.

    • mpaul
      Posted Jan 18, 2010 at 11:55 PM | Permalink

      Agreed, but the periodicity for the primary mechanisms is 1,000s and often 10s of thousands of years. The stochastics are still largely in play when the time scales are 50 or 100 years. I’m afraid that climate scientist are confusing weather with climate.

    • bender
      Posted Jan 19, 2010 at 6:35 PM | Permalink

      “When are the stochastics in play vs not?” That is the question. If you’d have asked Gavin 10 years ago, during a warm trend, he would have said over 10-year scales. You ask him now that it’s not warming and he says, umm, 30 years. You say 50-100. I’d like to see that question discussed by the authorities of the settled science. I’d like to see them prove that weather stops “here” and climate starts “there”. Instead, hand-waving about about “what you expect” vs. “what you get”. I want to see it in an IPCC report.

    • Steven Mosher
      Posted Jan 19, 2010 at 11:24 PM | Permalink

      ha, did you ever read the mail where jones discusses the 30 year period? Its in there.. very funny. I posted it over at Lucia’s
      the period is actually 35.. Perhaps we should go hunt up the study he refers to.

      If interested I can go look the mail up.. or just search
      on the word “35” only a couple mails pop up.

    • Richard Drake
      Posted Jan 20, 2010 at 8:48 AM | Permalink

      “When are the stochastics in play vs not?” … I’d like to see that question discussed by the authorities of the settled science … I want to see it in an IPCC report.

      It’s outrageous that this has not been a major emphasis on this at the IPCC level. The superciliousness of the typical alarmist – I’m thinking George Monbiot in the December debate I attended with James Delingpole in London, or John Hirst, head of the Met Office, confronted by Andrew Neil on BBC TV more recently – that those of us less than impressed by the Met’s regional forecasting 3-6 months out or by the lack of success of the GCMs 10-15 years out haven’t grasped the basic fact of the settled science – the difference between weather and climate. And the magic number of thirty years where one wonderfully morphs into the other is deduced from real world data where exactly? Feynman would make mincemeat of these people.

    • Judith Curry
      Posted Jan 24, 2010 at 8:24 AM | Permalink

      The weather/climate issue is an interesting one. NOAA formally defines climate as anything longer than two weeks (which is the period for which they do weather forecasts). Does this make sense? of course not. There is a weather/climate continuum. In the old days, before we understood the longer period ocean oscillations like PDO and AMO, 30 years was a good “averaging period” for climatology. If you are doing trends, 30 or 35 years doesn’t work if you are say starting at the coldest part of the AMO and ending at the warmest part. I have argued (in the context of my analysis of hurricane activity) that averaging should be done over discrete periods of AMO/PDO phase combinations, then trends can be determined by differencing between two successive like phase combinations (e.g. the warm amo-warm pdo periods of the 1930’s vs 1995~2002). The statistical significance of doing something like this is rather daunting, but the physics of what is going on suggests that this is the way to do trends for the 20th century.

      Back to the weather/climate continuum. The main impacts of climate change are mainly associated with changing frequencies and intensities of extreme weather events!

      Tim Palmer of ECMWF is advocating that the best climate models (e.g. ECHAM5) have the same atmospheric and ocean components as the weather models and seasonal climate models, which are evaluated on a daily basis. He further argues that to get the fast feedbacks correct (e.g. cloud and water vapor), that the weather systems need to be resolved and modeled correctly, which requires requires resolution on a scale of order 10 km (which the ECMWF model now has). ECHAM model has just completed 12 km resolution simulations of the climate model on the ORNL computer, one would hope that these simulations would be a definitive source of info on modeled cloud/water vapor feedbacks

    • Charlie A
      Posted Jan 24, 2010 at 1:40 PM | Permalink

      Slightly off topic, …..snip

    • EdeF
      Posted Jan 20, 2010 at 12:59 PM | Permalink

      Any computer simulation can be evaluated. I propose the following tests of the GCMs (pick any one) over a very limited future timescale. Here are my tests:

      a) The number of named storms in the Carribean July-Nov 2013.

      b) The monthly rainfall at Seoul, Korea for the monsoon month of July 2012.

      c) The number of days above 110 deg F at Death Valley, Calif. August 2015.

      d) The average temperature for the month of January 2011 at Managua, Nicauragua.

      e) Total snowfall for Elmau, Austria Dec 2013 to March 2014.

      I will guess the values by averaging the previous 5 years data. If the GCMs can beat me I will buy their team two cases of Dos Equis XX. Test to be concluded September 2015. Any takers?

    • WillR
      Posted Jan 20, 2010 at 1:35 PM | Permalink

      Re: EdeF (Jan 20 12:59),

      Considering that the confidence is very high on the other side of the debate — maybe they can go 10-to-1 against you.

      Just be careful of alcohol poisoning…

  • Contrarian
    Posted Jan 19, 2010 at 4:47 AM | Permalink

    Dr Curry,

    You asked, “commiebob, a question for you. Would you expect a complex nonlinear system (like the climate) to be treatable by a simple linear feedback analysis? What is the scope of system complexity that you try to analyze using control theory?”

    A complex, nonlinear system is still a black box from the standpoint of an external observer. It receives an input from an external source, and produces an output which is some function of the input. While mechanisms inside the box determine that function, we have no hope of elucidating it without good data on I/O. While measurements of the TOA energy balance in the tropics are surely insufficient, they are necessary and relevant. Moreover, if there are differences in the radiative balance with latitude, the models should embody an explanatory mechanism for those differences and predict them.

    Thanks for joining the discussion. This is “peer-to-peer” review at its best!

    • Craig Loehle
      Posted Jan 19, 2010 at 9:43 AM | Permalink

      Of course the problem here is that with the climate system we are only allowed one perturbation of the real system (20th Century climate), which is under-determined wrt dynamics of the complex model. We can of course perturb the simulations any way we want, but only if “we” are part of one of the modeling teams.

    • Bernie
      Posted Jan 20, 2010 at 9:48 AM | Permalink

      Doesn’t this point severely limit the value of feedback analysis for climate systems? It seems to me that this type of analysis is necessary but not sufficient for determinibng future states.

  • commieBob
    Posted Jan 19, 2010 at 12:13 PM | Permalink

    Hi Judith,

    Sorry for the slow reply.

    To answer your question: “Would you expect a complex nonlinear system (like the climate) to be treatable by a simple linear feedback analysis? What is the scope of system complexity that you try to analyze using control theory?”

    1 – I bend over backwards to eliminate complexity especially in cases where the system is not well understood. A poorly understood complex nonlinear system is not reliably treatable with simple linear feedback analysis (or often, to be fair, any analysis).

    2 – On the other hand, a well understood (albeit complex and nonlinear) system is often treatable using a rather simple analysis. The history of my own field (Electronics) is one of simplification. As we come to understand systems, the analysis becomes simpler because we know what we can safely ignore.

    What I didn’t include in my original post were the constraints on my trust of LC:

    a – The analysis deals with an obvious first order effect
    b – which occurs over a short period of time.

    As long as the above constraints are met, the nature of the system within the black box doesn’t usually matter.

    (rant)The trouble is that, once we have found a valid correlation, we are tempted to take that as proof of a bunch of other stuff that we haven’t actually proved.(/rant)

Dennis Wingo

Just as a reference…..

I am working on Nimbus data from the 1960’s and have found probably the first paper related to Earth Radiation Budget in the Arctic and Antarctic regions, based on IR data from the Nimbus II HRIR sensor.

The Radiation Balance of the Earth-Atmosphere System Over Both Polar Regions Obtained from Radiation Measurements of the Nimbus II Meteorological Satellite”

Just a heads up to interested parties.

Judith Curry

I have a short time to comment, more time this eve. I am not critical that they only examine the tropics, but that they claim that an examination of the tropics is sufficient to diagnose global sensitivity. It is not sufficient, as I outline in my post.

• Dave Dardinger
  Posted Jan 18, 2010 at 2:33 PM | Permalink

  Re: Judith Curry (Jan 18 14:12),

  Dr. Curry,

  I don’t know if you’ve actually posted on this new version of CA before, but you might want to press the Reply button on the post you’re responding to so people will be able to tell who you’re answering. In this case I assume it’s the Mike B message of 12:07. Also, as this is likely to be a very long thread, you probably also need to have the CA Assistant (see top right corner of the page), as we’ve got nested comments which are a bear to navigate without it.

  • Judith Curry
    Posted Jan 18, 2010 at 4:24 PM | Permalink

    Thanks Dave, i think i have it figured out

• JamesG
  Posted Jan 19, 2010 at 5:40 PM | Permalink

  I thought this was because most feedback papers do the same thing, on the assumption that the feedback will be strongest at the tropics, Dessler for example explains it here:

  Guest Post By Andrew Dessler On The Water Vapor Feedback

  “Q. Why is the tropical upper troposphere so important for the water vapor feedback?

  A. It is the changes in water vapor in the tropical upper troposphere that plays the major role in the water vapor feedback. While photons from these water vapor molecules do not directly heat the surface, they do primarily regulate emission of energy to space. Because the troposphere is rapidly mixed by convection at a rate much faster than radiation, the effect of changes due to radiation fluxes that are entirely internal to the troposphere (e.g., due to changes in lower tropospheric water) will be rapidly wiped out by convection and have a small net impact on surface temperature. The tropics dominate the effect because of the smaller temperature difference between the surface and the upper troposphere in the mid-latitudes combined with smaller column abundances of water vapor there. “

mccall

FWIW (and echoing Lubos point), Dr. Lindzen had acknowledge much of criticisms before Dr. Schmidt in a recent RC post went (arguably) well over the line in claims against the paper. As a result, a follow-up LC paper is circulating (not sure if it’s a re-issue or a corrigendum?) that addresses the criticisms with little/no impact on the “models still substantially overstate CO2 sensitivity” summary.

• Judith Curry
  Posted Jan 18, 2010 at 4:28 PM | Permalink

  mccall, my original essay was written on Dec 26 (see a post i just made further down on the thread), before the recent spate of postings on RC and elsewhere. I haven’t seen the revised LC paper (would appreciate a link if anyone has it). Apart from the critique by Trenberth et al. (which is what i assume LC respond to), my main concerns are inferring global sensitivity from this analysis of the tropics, misapplication of the sensitivity analysis based on a global energy balance model to a specific region, and deficiencies in the overall approach to inferring climate sensitivity using this kind of model.

  • Judith Curry
    Posted Jan 18, 2010 at 4:45 PM | Permalink

    i am having difficulty posting this as a new comment, “awaiting moderation”, so i’m posting here for now

    I just noticed that Steve didn’t post my final version of this little essay, here is the updated text:

    ————
    Update: this essay was finished on Dec 26. Steve decided to wait a few weeks before posting, given all the interest in climategate. Since then, there is now a formal reply to the LC paper that is in press in GRL by Trenberth, Fasullo, O’Dell and Wong, this is dicussed at RealClimate http://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/ and http://www.realclimate.org/index.php/archives/2010/01/lindzen-and-choi-unraveled/. See also DotEarth http://dotearth.blogs.nytimes.com/2010/01/08/a-rebuttal-to-a-cool-climate-paper/
    ———–

  • mccall
    Posted Jan 18, 2010 at 9:42 PM | Permalink

    Thank you for clarifying the time line, Dr. Curry.

    Dr. Lindzen’s comment and response (I’m trying to locate it) were to Gavin’s Schmidt’s RC posting. As I recall, RL mentioned that most of the scientific critiques came to him via e-mail or other direct correspondence (I believe Wong was mentioned specifically), but perhaps yours are some of them. RL’s more pointed retort was to GS/RC was that their criticisms were mostly/if not all addressed in “revision” , and the high CO2 sensitivity claims for modeling (including feedbacks), still could not be sustained. Absent the revision, it’s not clear whether L-C have addressed your questions/objections, nor any others (fundamental or stretch) for that matter…

    • Judith Curry
      Posted Jan 19, 2010 at 7:41 AM | Permalink

      I haven’t written to RL on this. When I wrote this around Xmas, all was quiet on the LC front in the blogosphere (as far as I can tell), then a recent flurry of activity and I haven’t caught up on all of it. would appreciate pointers (i’ve seen RC, dotearth, and now Lubos)

Jack Okie

Thank you, Dr. Curry, for being willing to engage on this site. It is enormously helpful to understand the issues behind the findings. Please continue.

• Judith Curry
  Posted Jan 18, 2010 at 4:28 PM | Permalink

  Jack, thanks for your comment!

LennartS Sollentuna

Has anyone a pointer to the up-dated Lindzen & Choi paper?

• David L. Hagen
  Posted Jan 18, 2010 at 7:12 PM | Permalink

  LennartS Sollentuna – Here are some links.
  On the determination of climate feedbacks from ERBE data
  Richard S. Lindzen and Yong-Sang Choi, Received 16 June 2009; revised 14 July 2009; accepted 20 July 2009; published 26 August 2009. (c/o DrRoySpencer.com)

  ON THE DETERMINATION OF CLIMATE FEEDBACKS FROM ERBE DATA Richard S. Lindzen and Yong-Sang Choi | July 24, 2009 (c/o JoanneNova.com.au)

  On the Determination of Climate Feedbacks from ERBE Data Richard S. Lindzen & Yong-Sang Choi, Wednesday, 19 August 2009 (SPPI.com)

  Lindzen publication page.

  A Case Against
  Precipitous Climate ActionRichard S. Lindzen

Craig Loehle

A fundamental problem with the models wrt feedbacks is that no one can point to a simple experiment/data set that would be/is a clear unambiguous test of the way the models handle feedbacks. Spencer has shown one type of interpretation error. Lindzen/Choi attempt another. The 2002 GEWEX workshop linked above shows that at that time there was no ability to assess these critical assumptions. Models are all about assumptions and the best way to evaluate a complex model is to evaluate the assumptions individually–much more tractable when we can’t do experiments on the system. Evaluation, for example, of the input forcing of clouds and aerosols shows that the different models use different input data which means 1) we are uncertain about these forcings and 2) models using different forcing but getting the same answer either have a kludge to force the right answer or can not all be right. Either way, a problem. If Lindzen or Spencer are even roughly right, the models have a big big problem.

• Judith Curry
  Posted Jan 18, 2010 at 4:31 PM | Permalink

  Craig, thanks for your comment, i agree with most of what you say. If LC have identified a real problem in the models, it is almost certainly in the way that tropical deep convection is parameterized. This is a known deficiency in the models that is very vexing owing to the complex scales of motions involved and the difficulties in treating them with the relatively coarse resolution of global climate models

  • Judith Curry
    Posted Jan 18, 2010 at 6:38 PM | Permalink

    Actually, LC’s results are most consistent with a problem in treating low level clouds in the tropics

    • BLouis79
      Posted Jan 21, 2010 at 3:44 PM | Permalink

      But don’t the models have problems dealing with low level cloud everywhere?

      And don’t low level clouds provide significant negative feedbacks?

• Harold
  Posted Jan 19, 2010 at 8:38 AM | Permalink

  Craig –

  I’ve seen the comment from time to time that controlled experiments can’t be done to evaluate the models (IPCC says this as well). This is not true – there are a number of geoengineering proposals which could be used in exactly this way. People who don’t want geoengineering argue that it’s too risky, because something really bad might happen. On the other hand, they are usually arguing we have to do something because something really bad IS going to happen. Where’s the logic in that?

  In any event, I tend toward the previous modelers desire for a step function to analyze.

D Bonson

Thank you Judith Curry for engaging in these discussions. I would like to read from you a response to Luboš Motl’s post (Posted Jan 18, 2010 at 11:12 AM).

• Judith Curry
  Posted Jan 18, 2010 at 6:07 PM | Permalink

  I’ve posted one now

Judith Curry

I just noticed that Steve didn’t post my final version of this little essay, here is the updated text:

————
Update: this essay was finished on Dec 26. Steve decided to wait a few weeks before posting, given all the interest in climategate. Since then, there is now a formal reply to the LC paper that is in press in GRL by Trenberth, Fasullo, O’Dell and Wong, this is dicussed at RealClimate http://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/ and http://www.realclimate.org/index.php/archives/2010/01/lindzen-and-choi-unraveled/. See also DotEarth http://dotearth.blogs.nytimes.com/2010/01/08/a-rebuttal-to-a-cool-climate-paper/
———–

Slabadang

LC´s method is genius!

Because now the evidence of the “sensitive”
climat has to be proofed by the warmists.
I´m reading and cant find the logic of the critisism.LC underlines that they focused on the tropics.Where is the mesured evidence that the rest of the globe has less outgoing radiation?.And to compensate for the tropics it has to be far less than the “models” predicts.It just doesn´t add up!
LC delivered a vital part of the understanding of the globes radiation.Curry seems to have no clue of radiation not in the tropics and not at the Arctic.

RomanM: If you have a valid point to make, do it. There is no reason to include a personal attack on Dr. Curry. Please refrain from doing so in the future.

• Derek H
  Posted Jan 18, 2010 at 9:44 PM | Permalink

  1. Slabadang, please be polite. I would like to see more of Dr. Curry’s explanations here because she at least is striking a reasonable tone and appears to be intellectually honest. I have found Schmidt, Mann, Hansen et al to be rather strident, arrogant and either dishonest or misleading; I would like a conversation with AGW proponents who are none of that.

  2. Can someone please translate this diatribe into English?

  • Steven Mosher
    Posted Jan 19, 2010 at 3:41 PM | Permalink

    No need to compare her behavior with others. The difference speaks for itself.

    • Bill Hammock
      Posted Jan 20, 2010 at 8:03 AM | Permalink

      Yeah, actions speak louder.

      So, you went on and published the personal e-mails of the CRU lab.
      And started screaming that ‘trick’ is paramount evidence of dishonesty, while it was just an innocent expression.

      You are among the group of people that polarized the discussion and polarising it even further.

      What Dr Curry is doing is exceptional. It is a single voice in the denier cacophony.

    • Bill Hammock
      Posted Jan 20, 2010 at 5:02 PM | Permalink

      It is exactly this type of replies that drive away people and diminish constructive criticism on these blogs.

      You give a vague reply and you quickly move on to something else. It is always moving to something else and never finishing a subject.

      The word ‘trick’ was used to describe a smart technique in the research work. Simply by looking into the context of the e-mails it screams that there was nothing suspicious about it. If the ‘trick’ was the best of the examples of suspicious work by the CRU, then, frankly, you are out of arguments.

      What I know is that those who polarize the debate are those without good arguments.

    • Bill Hammock
      Posted Jan 20, 2010 at 9:12 PM | Permalink

      OT

    • Bill Hammock
      Posted Jan 21, 2010 at 12:36 PM | Permalink

      So, what happened here is the moderator erased my text about the ‘trick/decline’ issue and replaced it with “OT”.

      A respectable moderator would at least mention that the ‘OT’ is his text, as they do in other blogs.

      For someone who wants to search, they can find that ‘trick/decline’ is a non-issue, and not dishonest at all.

      The denier club is losing it. Just like the smokers were misled by the tobacco industry in the 20th century and kept smoking, you are taken for a ride by the fossil fuel industry.

      Good luck to Dr Curry.

      Steve: This has nothing to do with Judy Curry’s post.

    • Richard Drake
      Posted Jan 21, 2010 at 12:51 PM | Permalink

      The moderator here is terse but effective. There’s no point comparing with other places – they probably haven’t kept focus on the science as well as this one has. ‘Hide the decline’ has been judged off topic, no doubt partly because it’s been dealt with so often before, for example on 10 Dec and before that on 26 Nov. They are worth careful study.

Jeremy

JC, wrt your second point… why does a focus on shorter time-scale (Nth order) affects on climate negate LC results? If the climate system were an Nth order ordinary differential equation (which isn’t too far from the truth) the shorter time-scale affects would be the higher orders and should therefore have the capability to completely overwhelm the lower-order (N-x) influences, am I right? You seem to be making the point that since these lower-order (longer time-scale) issues are not considered in LC, then the study does not apply.

This to me sounds like saying that in an equation such as this:

X(t)= a*y(t) + b*z(t)^2 + c*w(t)^3 + d*u(t)^4 (where a,b,c,d,t,u,w,X,y,z >=0)

…that the u(t)^4 term can be ignored in favor of the z(t)^2 term. This is mathematically difficult to justify unless your coefficients are known, and/or known to be non-linear. If we allow for that to be the case, which I will admit is a reasonable allowance given our limited analytical understanding of climate, then I should think that some very simple laboratory experiments would demonstrate these lower-order positive feed-backs to rule the day.

We know that changes in cloud-cover affects the temperature of an area in a very short amount of time, and alters it more drastically than the longer-time-scale influences in perhaps hundreds of years. Put simply, why does a study of the large influence of shorter-time-scale negative feed-backs to global temperature not apply in a discussion of where climate will go simply because longer-time-scale positive feed-backs are not considered? Certainly that which has the greatest influence per unit time on temperature has the greatest potential to alter the total energy content of our atmosphere.

• Dave Dardinger
  Posted Jan 18, 2010 at 6:00 PM | Permalink

  Re: Jeremy (Jan 18 17:20),

  Put simply, why does a study of the large influence of shorter-time-scale negative feed-backs to global temperature not apply in a discussion of where climate will go simply because longer-time-scale positive feed-backs are not considered?

  This is the way of looking at things that I was needing. Let me try repeating what you’re saying, and you can tell me if I’ve got it right. If we have two feed backs, one a short time-scale negative feedback and the other a long time-scale positive feedback, the short time-scale negative feedback will keep the temperature rise (in the case we’re looking at)lower; essentially as much as it can be held low. So if the non-feedback rise was 2 deg C, then the negative feedback might keep it to .5 deg C. This, then, is what the positive feedback would have to work with, not the 2 deg C rise. It might eventually produce a large rise, but it would take an even longer time than in the 2 deg C case (assuming some sort of quasi-linear effect). And depending or what sort of negative feedback we’re dealing with, it’s feedback might become even more pronounced at higher temperatures thus dampening the positive feedback even more.

• Judith Curry
  Posted Jan 18, 2010 at 6:14 PM | Permalink

  Jeremy, a focus on shorter (rather intermediate) time scales doesn’t negate their results, but it limits what kind of conclusions can be drawn from the analysis. Dave, you are hitting on an important point that the feedbacks are frequency dependent and the overall feedback for what might happen on the time scale of a century is a complex interaction of a number of nonlinear feedbacks operating over a range of time scales. Doubtful that all this can be captured by a simple linear feedback analysis such as LC

  • Dave Dardinger
    Posted Jan 18, 2010 at 6:29 PM | Permalink

    Re: Judith Curry (Jan 18 18:14),

    Doubtful that all this can be captured by a simple linear feedback analysis such as LC

    But can it be captured by GCMs either? The problem isn’t so much that a GCM can’t crunch the numbers properly, but have the physical problems been properly worked out and described in the literature so that they can be put into a GCM? The IPCC has admitted that things like clouds are the least known theoretically. That being the case, why should we reject what is essentially a cloud feedback by LC without careful examination of the properties it has? Not that I mind a discussion of the yeas and nays here. I welcome it and I hope that’s what happens.

    There’s also the point a couple of people have made that even if the LC formulation can’t be extended to a global formulation it still may be useful for estimating the feedback situation.

    • Judith Curry
      Posted Jan 18, 2010 at 6:36 PM | Permalink

      Dave, the LC method should ONLY be applied globally, it doesn’t make sense for a region, that is part of the problem. GCMs reproduce all scales of feedback processes, the question is whether cumulative feedbacks produced by the GCMs are correct. If LC attribute what they find to a cloud feedback, as i said in my post, the only cloud feedback that might have the fingerprint they find is one associated with low clouds over the ocean (that are unmasked by higher clouds above). There may be issues with how low clouds in the tropics are treated by the climate models, but how the climate models treat deep tropical convection seems to be the bigger issue (and was the issue that lindzen’s iris hypothesis raised).

    • Geoff Sherrington
      Posted Jan 18, 2010 at 10:06 PM | Permalink

      Is there a systematic change in the modelled feedbacks for each traditional latitude band that indicates that findings from non-tropical regions will weaken or strengthen the LC proposition?

      That is, if the proposition is found acceptable for the tropics, does it follow that the other global regions will be consistent with the conclusions, or inconsistent?

      So far, all I have read is that they will be different (as intuition might expect), but I have not read that they will be damaging or terminal.

    • Dave Dardinger
      Posted Jan 19, 2010 at 1:03 AM | Permalink

      Re: Judith Curry (Jan 18 18:36),

      If LC attribute what they find to a cloud feedback, as i said in my post, the only cloud feedback that might have the fingerprint they find is one associated with low clouds over the ocean (that are unmasked by higher clouds above).

      I’m somewhat confused here. I thought LC started out talking about increased CO2 resulting in the IR being emitted at a higher level, and thus a lower temperature, without considering feedbacks. LC then says the OLR increases (giving a negative feedback) in the Tropical ERBE readings while the models show decreases in OLR requiring a positive feedback in surface temperatures to produce equilibrium. Now LC don’t worry about the mechanism producing the increased OLR. Perhaps you’re correct as to what this would imply, but I’d like more than just hand waving as to low level; unmasked clouds being the “only” cloud feedback having the required fingerprint. Can you point me to a paper available online which discusses why this must be the case? I’d think there could be a variety of cloud configurations which would work.

  • Clif C
    Posted Jan 18, 2010 at 7:27 PM | Permalink

    I’m still waiting for the attractor.

40 Shades of Green

I would echo the general welcome already extended to to Professor Curry by others.

KevinUK

I glad to see that the L & C paper is now being audited on CA. Lord Monckton rather foolishly IMO has jumped on its conclusions rather as the experimental proof that the models are fundamental wrong in regard to climate sensitivity.

OT here I know but if anyone here is interested in looking at ‘global warming’ in full colour then take a look at this new thread that I’ve just put up on ‘digginintheclay’.

Mapping global warming

The main conclusion reached in the thread is that global warming is hardly global and that based on the evidence shown in the colour coded trend maps presented in the thread, ‘global warming’ is not global but is in fact largely NH winter warming. I’ve stated that given what the maps show, it’s hard to see how CO2 could be the cause of this warming unless ‘Demon CO2’ is happy to allow notable exceptions by being choosey and selectively allowing warming in parts of the planet while allowing other parts to cool at the same time.

I’ve suggested that Western Australians apply for a rebate on their carbon taxes and have also recommended where ‘pommies’ like myself should all go if we want a good tan this summer.

Regards

KevinUK

Slabadang

Kevin!
How come your modells dont show what LC measured?

Kenneth Fritsch

I am glad to see that CA is back to analyzing climate papers again as the climategate discussions were getting a bit stale.

I have nothing to add to this discussion, by way of technical comments, but I note that when papers are criticized/analyzed, like the Santer and Douglass exchanges and this one, we see more readily just how uncertain the science and models really are.

I did particularly like Craig Loehle’s post on having no experimental means of evaluating climate models (no absolute standard to compare to) and therefore we need to compare climate models and look for significant differences. If all models agreed, we might have more confidence that the chance of agreement is better than all being exactly wrong to the same extent. Significant differences between model results, of course, means that one might be correct and one wrong or they might both be wrong and different. I have been taking this approach in comparing temperature data sets.

• Judith Curry
  Posted Jan 18, 2010 at 10:28 PM | Permalink

  Kenneth, I agree that it is good see something on the blogs other than climategate! Craig Loehle has hit the nail on the head in terms of lacking good experimental means of evaluating climate models. The gewex link at the end of my essay was targeted at trying to figure out how to more effectively use satellite data to evaluate climate models. this is very important, but the climate modelling community hasn’t really come up with good evaluation metrics

  LC (and Douglass et al) have been taking the approach of using satellite datasets for the tropics and evaluating climate models. The metrics they propose are reasonable for evaluating climate models (delta Flux/delta SST; trend of upper tropospheric temperatures). Most of the models don’t compare very will with observations. this is valuable information, especially if the observations can identify what aspects of the models need improving. My objection is when the results are over interpreted, i.e. in my opinion the LC analysis is not a convincing observational determination of climate sensitivity.

  • bender
    Posted Jan 18, 2010 at 11:46 PM | Permalink

    My objection is when the results are over interpreted

    Agreed. But, JC, is this a “fatal flaw” which would cause you to reject the paper outright, with no hope of publishing? Or would you reject with invitation to re-submit after dialing back the rhetoric? Or would you accept after “major revision”? I’m trying to understand to what degree you disagree with this paper. Sounds like you’re already back-pedaling somewhat from your original review (which is what I would have predicted).

    • Judith Curry
      Posted Jan 24, 2010 at 8:04 AM | Permalink

      If i had been a reviewer of this paper, i would say “major revisions needed.” I would have asked that they they focus their interpretation only on evaluating the climate model simulations of the tropics, and not claim that this is of any particular relevance to global climate sensitivity. In any event, the paper certainly should have been published, even if some of the analysis and much of the interpretation is not correct. This paper is stimulating further research and is challenging models with observations which is always valuable. The overhyping of this paper as “the end to the AGW hoax” is annoying, but at the end of the day not all that important (although this is the sort of thing that seem to send those involved in the hacked CRU emails into quite a tizzy).

  • Derek H
    Posted Jan 19, 2010 at 10:33 AM | Permalink

    Dr. Curry, I agree, I think some ideologues went way overboard in labeling LC as an AGW-killer but you raise a fundamental point that I never see the mainstream press cover and IPCC doesn’t seem to want to acknowledge: many of the models don’t compare well to actual observations.

    I am still astounded that apparently legitimate scientists accept paleoclimatological analysis using proxies when those proxies apparently don’t conform to the last 30-40 years of observations (and probably the BEST period of observation to boot!). Perhaps you could explain that paradox to me and I can get rid of the hobgoblin in the back of my mind?

    • Jeff Alberts
      Posted Jan 19, 2010 at 12:59 PM | Permalink

      I think people should keep the discussion to the paper and critique thereof…

eddy

Many thanks for this, Judith.

Overall: More of this kind of stuff, please!

• Judith Curry
  Posted Jan 18, 2010 at 7:53 PM | Permalink

  Thanks eddy!

Alexander Harvey

Judith,

This is a bit of topic, but I wish to use this opportunity to highlight something that troubles me. Whenever the subject of feedbacks comes up I always get the unnerving feeling that I am in Denmark with Hamlet yet the ghost never appears. The ghost in question being phase.
Feedbacks, both positive and negetive, have important implications for both diurnal and seasonal phase lags. Focussing on seasonal lags, it seems to me that there may be very little room for large feedback effects either positive or negetive. The seasonal lags can, with care, be computed from a gridded climatology like the Hadley Centre´s. In the midlatitudes, they show interesting global patterns reflecting both the differences between land and sea but more crucially the effects of the prevailing winds and ocean gyres as they move phase about. These efects I feel can be emulated by a model that moves phasors associated with the atmosphere and oceans across the globe. In such an approach the positions of the phase minimum located around Mongolia and the phase maximum in the Pacific can be accounted for.

Now large positive feedbacks would have the tendency to increase phase lags noticiably, and negetive ones to minimise them. Also any latency in the feedback response could cause instability to set in where the simpler approach of ignoring phase would not have indicated it. Such latencies particularly if cascaded could give rise to instability with negetive feedbacks once the total phase lag of the signal fed back exceeds pi/2.

In my opinion, and it is just that an opinion, the phase lags that can be computed from the Hadley climatology are consistent with low levels of feedback. The seasonal phase over the oceans falls largely in the range (pi/3 +/- pi/12) which is quite moderate. It seems to me that large amounts of positive feedback, particular with a latency that is a significant proportion of one year, would indicate infeasible small underlying phase lags. Also I doubt that signifiacnt negetive feedbacks with similar significant latencies could be applied without triggering instabilities.

I did quite a lot of work on this many moons ago and I should like for someone with the resources and necessary wit to consider such an approach. I admit that it would probably only provide a sense of the limits to feedbacks as the phasors associated with the land, ocean and atmosphere are hard to model with great accuracy, as is the modelling of the interaction of the phasors in relative motion, but the good news is that the data is I think quite robust in that great time and care has gone into the production of the climatologies, which I feel is evidenced by the coherent and detailed phase picture one gets from an analysis of the midlatitudual Northern Hemisphere.

As an aside: the climatologies also contain important information regarding linearity due to what I consider to be very low production of harmonics over the land masses. Over the oceans there is detectable non-linearity possible due to the seasonal augmentation and suppression of the well mixed layer.

I thank all for reading this far, it is appreciated. I do have procedures and results (but not readily to hand) for those that are interested.

Alex

• Judith Curry
  Posted Jan 18, 2010 at 7:52 PM | Permalink

  Alex, very good point. the feedbacks are frequency depended with complex phase lags and they are not easy to diagnose. The black box approach of LC “hopes” that there is some averaging period where there is equilibrium, and then the higher frequency feedbacks within this averaging period can be diagnosed. The LC approach is also based upon a linear feedback analysis. The fact that isolated feedback processes (e.g. water vapor, ice albedo) are not additive reflects the nonlinearity of the system and gives hints why the LC approach is inadequate. I would be interested in hearing more about your thoughts on this

vg

I find this statement extraordinary
“Cameron, the fingerprint of of AGW is most evident in the high latitudes of the northern hemisphere”
Please explain why

Why not the low latitudes of the southern hemisphere?
The whole concept of “global” has been suddenly thrown out

Thanks for your contribution Dr Curry this is more like a real debate

Tom

I would like to ask those who are able to answer; this question. In real terms, you all agree that mankind, has the ability to determine with certinty the 1/2 a degree(F),(or less) global warming over the last ten years? The world we live upon is very dynamic, to say the least. The over-under has got to be at least a degree or more:), on a planet like ours. You all think you really can get it down to fractions? And over these time frames and all this “new science” right out of the box?… It bogles my mind to think you can be so certin about such small measurements over such a vast area.

• jaffa
  Posted Jan 18, 2010 at 10:39 PM | Permalink

  This point was the source of my initial scepticism. I simply can’t believe that ‘global temperature’ can be determined to fractions of a degree even using measurement data. Once proxies are introduced the whole claim seems to be ridiculous.

  Can someone clarify what is meant by ‘global temperature’? Is it an average of daily maximums, daily means or something else. How do those analysing the data compensate for the huge (in relation to the suggested warming trend) daily or even hourly changes, day/night changes, seasonal variation and longer term natural variations.

  Finally I had assumed that high quality, reliable data was being used, with satellite measurements covering the entire globe. Isn’t it?

  Perhaps someone will be kind enough to point those of us who think there are lies, damned lies, and statistics to a web page that makes sense of the apparent nonsense.

  • See - owe to Rich
    Posted Jan 19, 2010 at 5:13 PM | Permalink

    Jaffa, the law of large numbers means that a lot of data with medium uncertainty can be averaged to give a result with fairly low uncertainty. By looking at, for example, the HadCRUT3 data and the UAH satellite data you can get a feel for how much uncertainty. The standard deviation of the last 10 years’ of HadCRUT3 annual data is less than 0.1degC I think.

    Nevertheless, the law of large numbers requires that independent errors be allowed to cancel out, approximately. Hence auditting is vital to ensure that biasses, accidental or otherwise, are not allowed to creep in.

    HTH,
    Rich.

    • Carl Gullans
      Posted Jan 20, 2010 at 8:59 AM | Permalink

      Yes… although you are aware of this, I’ll mention this for jaffa and others who are unfamiliar… HadCRUT3 is *known* to have biases that have creeped in. So, you are right that using adjusted data, and claiming a low standard deviation, is completely wrong. Somebody wrote a pretty good explanation of this recently (ChiefIO, Bishop Hill? anybody who knows what I’m talking about, please help), showing that all adjustment decisions need to carry an error term going forward, but that they currently don’t.

  • Steven Mosher
    Posted Jan 19, 2010 at 11:37 PM | Permalink

    Jaffa.

    The “average” is estimated as follows Tave= (Tmax+Tmin)/2

    That is the max of the day and the min of the day are added and divided by 2.

    It’s been shown ( and you can see for yourself by looking at CRN data which is collected every 5 minutes) that this is roughly equal to the integrated value of temperature for a 24 cycle. As others have noted the law of large numbers is your friend and you get a good estimate of the monthly average ( arguments about the physical ‘reality’ of this number abound) The most important thing however is the understanding of the tren over long periods of time. Good places to start are Lucias blog which addresses some of these issues and threads all over CA.

Dirk

Perhaps I misunderstood, or something was mis-spoken, but the change in which stations are included in the temperature data over the past 30 years- removing high-altitude stations- couldn’t this account for the tropical land “warming”? One example given on the recent John Coleman report was that Bolivia’s temperature is now determined by low-altitude stations as high altitude stations are no longer included- creating a big red warming blip over Bolivia- true?

Also- why would altitude change the properties of radiation relative to wavelength and CO2- is it concentration, or temperature, or albedo of sea ice vs. oil vs. plastic vs. plankton? So what are the possible variables that create concern over applying the results of the tropics to global behavior?

• Judith Curry
  Posted Jan 19, 2010 at 8:09 AM | Permalink

  Dirk, different regions with differing surface characteristics, clouds, water vapor, and locations with different wind conditions respond differently to global forcing and the natural modes of climate variability. See the links i posted for the global maps of observed and projected temperature change in my original post.

  The tropics are characterized by low surface reflectivity, a very large amount of water vapor, and clouds that include deep convection and high cirrus. The tropical atmosphere is fairly opaque to IR radiation, and the so called “water vapor window” has a shutter over it in the lower tropical atmosphere (owing to large concentrations of water vapor) so virtually no IR emitted by the surface reaches space as it is absorbed in the lower atmosphere. This is why most of the radiative action in the tropics is in the upper troposphere.

  • Patrik
    Posted Jan 19, 2010 at 10:07 AM | Permalink

    Dr Curry>> “The tropical atmosphere is fairly opaque to IR radiation, and the so called “water vapor window” has a shutter over it in the lower tropical atmosphere (owing to large concentrations of water vapor) so virtually no IR emitted by the surface reaches space as it is absorbed in the lower atmosphere.”
    Isn’t this a very short and precise description for why the LC paper is meaningless?
    Because, if what You write is true, then added CO2 should make no difference what so ever in the tropics – right?
    But, wouldn’t it also then be true that the man made warming can’t happen in the tropics, because there is no additional greenhouse effect possible in the tropics?
    The question that follows is; in the polar regions we have virually no water vapor, right?
    So, even though added CO2 can warm the polar regions to some extent (~1-2 K?) – no feedbacks will happen there, because of the non-existing water vapor?
    So, the extra greenhouse effect that our CO2 can create, can only really appear and interact with H2O in other climate zones? Temperate, sub-tropical (?)..?
    Is my reasoning correct?

    • Judith Curry
      Posted Jan 19, 2010 at 6:29 PM | Permalink

      Patrik, you make an important point. Because of the opacity of the tropical atmosphere, doubling of CO2 had very little direct effect on the tropical surface temperature, most of the radiation action in the tropics is in the upper troposphere where there is less water vapor.

      This reasoning further makes the point that it doesn’t make any sense to try to determine the climate sensitivity from an analysis of the tropics

    • Patrik
      Posted Jan 20, 2010 at 10:18 AM | Permalink

      Ok, thanks for the answer. Could You please explain what kind of “action” You’re referring to in the upper troposphere above the tropics – since no LWR will reach the higher layers?

    • David A
      Posted Jan 26, 2010 at 11:40 AM | Permalink

      I thought that one of the points of the paper was that the “models” did show a warming in the very area studied and the observations were of the opposite sign.

      If that is true then there would be an affect on the models overal AGW projection based on the percentage of the overall “warming” affected by new understanding of this area limited area.

vg

How in earth could anyone think that they would be able to model climate? you would have to be able to predict the suns behaviour Sunspots, geomagnetism), our surrounding universe (cosmic rays). Earths wobble etc… One example: Its been raining cats and dogs here in Australia “drought is over” even with a significant El Nino. The most we could hope for is short term forecasting and even then it doesn’t seem to work. For factual data (correct me if I am wrong) the only models that seem to predict significant events correctly such as the recent cold spell in Europe, based on sun activity are those put out by Farmers Journal is it Piers Corbyn?

Colin_d

Thanks Judith and CA for the review and discussion. A pebble in my shoe in all of this is how it contrasts starkly with the “Science is Settled” mantra. It is far from settled and it is bordering on obscene that far-reaching changes are attempted based on one possible interpretation of this ‘unsettled science’.

• Judith Curry
  Posted Jan 19, 2010 at 7:56 AM | Permalink

  Colin, the “science is settled” is political statement, not a scientific statement! Decision making under uncertainty is often done facing conditions of much greater uncertainty than say the IPCC report. Even the IPCC report gives probabilities for its conclusions (none reach 100%, although they do say that warming in the latter half of the 20th century is “unequivocal”)

  • Kenneth Fritsch
    Posted Jan 19, 2010 at 10:23 AM | Permalink

    From this link and excerpts from it below we have the following development from the IPCC on “the science is settled”. That that statement in quotes is a political one and not a scientific one is rather evident from this new development. It further impugnes the science bent of the IPCC versus what many here have seen as a political one. Please note that the probability of this predicted occurrence was agreed by “experts” to be better than 90%. Since the IPCC only reveals in very general terms how the experts establish these probabilities we can only guess that it might have the average of the guesses of experts and on a subject that they were obviously oblivios.

    http://www.timesonline.co.uk/tol/news/environment/article6991177.ece

    Two years ago the Intergovernmental Panel on Climate Change (IPCC) issued a benchmark report that was claimed to incorporate the latest and most detailed research into the impact of global warming. A central claim was the world’s glaciers were melting so fast that those in the Himalayas could vanish by 2035.

    In the past few days the scientists behind the warning have admitted that it was based on a news story in the New Scientist, a popular science journal, published eight years before the IPCC’s 2007 report.

    ..Hasnain has since admitted that the claim was “speculation” and was not supported by any formal research. If confirmed it would be one of the most serious failures yet seen in climate research. The IPCC was set up precisely to ensure that world leaders had the best possible scientific advice on climate change.

    …When finally published, the IPCC report did give its source as the WWF study but went further, suggesting the likelihood of the glaciers melting was “very high”. The IPCC defines this as having a probability of greater than 90%.
    The report read: “Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate.”

    • Judith Curry
      Posted Jan 19, 2010 at 6:25 PM | Permalink

      I am astonished and disgusted by this. I am surprised that something like this snuck all the way through the IPCC review process. This is a much bigger black eye to the IPCC than hockeystick stuff

    • Dave Dardinger
      Posted Jan 19, 2010 at 6:59 PM | Permalink

      Re: Judith Curry (Jan 19 18:25),

      Dr. Curry,

      I have a question which I’d not normally ask here, but since Steve Mc is off enjoying the other sort of curry, I’ll throw it out. We have a fair number of people who come here and say that maybe the the hockeystick is bent and some of the team members aren’t paragons of virtue when it comes to upholding the Scientific Method, what about all the other things which point to AGW? Inevitably they point to melting glaciers at the top of their list of AGW proofs. Given the recent hit or two on the glacier front, could you give us the top 3 or 5 or whatever research areas which are clear indications that AGW exists at a measurable level?

    • Richard Drake
      Posted Jan 20, 2010 at 1:20 AM | Permalink

      Yes, it’s always said – it was said from the moment Climategate broke until now, it is said once again about the ridiculous Himalayan glacier situation – that this particular bad stuff doesn’t for one moment affect the other crucial evidence for AGW, evidence so significant, it is implied, as to warrant exactly the same worldwide reductions in carbon emissions as were being proposed already. But what precisely are those other lines of evidence? Not just evidence for warming, but for the fact that increased CO2 in the atmosphere is causing the warming and that this might lead to catastrophic results in the future. Polar bears? Sea levels? Where’s the anthropogenic stamp? As Dave says, what are the top 3-5 lines that are unaffected by what we’ve seen just these last two months?

  • Steven Mosher
    Posted Jan 19, 2010 at 3:23 PM | Permalink

    Thanks for that Dr. Curry, you’re a closet Lukewarmer I bet. As you note “the science is settled” is a political or sociological statement. All science has uncertainty and the vast majority of our behavior is carried out under the conditions of uncertainty, and even where its not, as in math and logic it’s good practice to check your work twice.

    • Judith Curry
      Posted Jan 19, 2010 at 6:21 PM | Permalink

      I am a “warmer” in the sense that I think the best evidence supports a warming of 1.5-4.5C for a doubling of CO2, all other things being equal. All other things are unlikely to be the same as in the 20th century such as solar variability, volcanic eruptions, ocean oscillations, so what the actual temperature change will be in the 21st century, i have no idea. I am a lukewarmer in the sense that I don’t see catastrophic impacts (except at the higher end of the warming).

    • Steven Mosher
      Posted Jan 19, 2010 at 6:54 PM | Permalink

      Basically, a Lukewarmer doesnt deny radiative physics, so GHGs warm the planet. We push for open access.

      We tend to hover around the 1.5C-2.0C figures.

      So. FUD

      F= Fear and alarmism.
      U= Uncertainity and the next right action.
      D= Denial and inaction

      We are in the U camp.

    • Richard Drake
      Posted Jan 20, 2010 at 1:10 AM | Permalink

      I’m in the U camp. But I’m not sure the camp agrees what the ‘next right action’ is. This may not the place for the full discussion but it’s a neat triangulation, thanks.

    • Carrick
      Posted Jan 22, 2010 at 2:28 AM | Permalink

      Steven Mosher:

      We tend to hover around the 1.5C-2.0C figures.

      Well, dang, I guess I’m not a luke warmer after all!

      Based on the known physics, I put climate sensitivity at around 2.5°C (range of 1.8 to 3.5C, I use geometric mean since that’s more appropriate for a log-normal variable like CO2 climate sensitivity). I allow that unknown physics could push this number lower, but I’m a firm believer that one makes one’s estimates based on what is known now, not speculation of what we’ll discover in the future.

      I guess I’m a catastrophe denier. Like Judith, I don’t see catastrophic consequences for humanity unless you get to the high end of allowed climate sensitivities.

    • See - owe to Rich
      Posted Jan 20, 2010 at 3:42 PM | Permalink

      Judith, I’m afraid they’re not going to let you into the lukewarmer club if your range goes as high as 4.5C. That really could mean serious heating by 2100AD.

      Mosher has set a range (1.5,2.0), but my personal lukewarmness has a range (1.0,2.0). It’s at the upper end if I believe HadCRUT3 has properly taken account of UHI – but I don’t really. I can’t quite explain why, but my faith in HadCRUT3 has taken a bit of a battering in the last few months.

      Rich.

    • Judith Curry
      Posted Jan 20, 2010 at 5:20 PM | Permalink

      The possibility for the upper end >3C is some tipping point like massive release of carbon from the tundra. This could be caused by combination CO2 and increasing soot on the surface in high latitudes. I would say that my range 1.5-4.5C is likely (>66% probability). Note IPCC said very unlikely that it is less than 2C. I can’t agree with that.

    • WillR
      Posted Jan 20, 2010 at 5:34 PM | Permalink

      Re: Judith Curry (Jan 20 17:20),

      Judith Said…
      The possibility for the upper end >3C is some tipping point like massive release of carbon from the tundra.

      That should be easy to test on Canadian tundra.

      Check the temperature records, move some tundra into a “greenhouse” increase average temperature and watch the CO2 Off gas…

      Better still, I guess you could even put the structure in place the summer before — measure the following summer. You could do a number of structures — and maintain a control even…

      Considering the $$$ at risk — I would think it would be easy to promote this experiment. Cheap experiment — maybe there’s some funding…???

    • Tolz
      Posted Jan 20, 2010 at 4:16 PM | Permalink

      Dr. Curry, doesn’t this “best evidence” have to include GCM predictions? And doesn’t even the low range of sensitivity require, basically, a positive cloud feedback?

    • Judith Curry
      Posted Jan 20, 2010 at 5:20 PM | Permalink

      I think you lukewarmer guys are “uncertainty deniers”, with such a narrow range 🙂

  • Colin_d
    Posted Jan 19, 2010 at 3:27 PM | Permalink

    Judith, a political slogan like that does not survive in isolation and the problem for science (and maybe its credibility will take a hit as a result) is that this one has been sustained by scientists. According to the IPCC it has been sustained by thousands of scientists and you don’t hear any protests from them that they are being mis-represented. As a scientist a lot of my work is at the interface between politics and science and it can be difficult to dampen the political desire for settled science.

    • Judith Curry
      Posted Jan 19, 2010 at 6:23 PM | Permalink

      Other than a few scientists that are actively advocating policies, i don’t think any scientists publicly state that the science is settled.

    • deadwood
      Posted Jan 19, 2010 at 8:26 PM | Permalink

      Dr. Curry, it is these “political” scientists that get the press and set the tone for all of the discourse on CO2 and its relationship to climate. Thus we find ourselves where we are with even good scientists like yourself referring to those of that don’t agree with the political “science” as “deniers”.

  • bender
    Posted Jan 19, 2010 at 6:59 PM | Permalink

    The arguemnt is not that “the science is settled”. That is a straw man well-loved in the denialosphere. The actual argument is that “the science is settled ENOUGH” … enough to move forward with mitigation and/or adaptation based on a precautionary principle. Very, very different things.

    • Richard Drake
      Posted Jan 19, 2010 at 7:55 PM | Permalink

      I agree and disagree. “The science is settled” has been proclaimed by not a few activists, so it’s not just a straw man set up by those opposed to them. All on the basis of 2000 of the “world’s top climate scientists” said to be full agreement with the IPCC. I’ve even seen people liken the situation to that of Einstein’s General Relativity – it’s that proven. But they never quite say what is that proven and that’s the catch.

      Of course you’re right about how the IPCC presents it. 90% confidence and all that (apart from the Himalayan glaciers disappearing by 2035 as it turns out). And I’m sure that’s the way Professor Curry would couch things, though with her own numbers.

      So, settled enough to make sure Africa’s coal never provides the cheap electricity it could for those that currently have none? How settled does the science need to be for that, for example, to be a legitimate consequence? (I know that’s out of bounds generally on CA and I’m sorry. Yet the idea of “settled enough” inevitably brings in all the myriad consequences, on both sides. I especially respect Freeman Dyson’s fervent championing of coal to power the poor out of poverty. You have to get your hands dirty with such questions in this area, it seems to me. Hard. Important.)

    • bender
      Posted Jan 19, 2010 at 9:28 PM | Permalink

      The science is settled” has been proclaimed by not a few activists

      .
      Do you really care what the activists proclaim? If so, why? Are we here to probe the science, or to correct activist misconceptions? I’m not interested in the latter. Plenty of blogospheric bandwidth devoted to that already. I don’t see that as CA’s function at all.

    • Richard Drake
      Posted Jan 20, 2010 at 12:57 AM | Permalink

      What about an activist called James Hansen and his comment about trains delivering coal to power stations being like “death trains”? Of course I care about what that very influential activist says, because of the potential impact on every human being of that way of thinking – especially those that do not already have electricity. And I also agree with you therefore – all the more so – that we should attend to the science. It was the phrase “settled enough” that did for me. You’re completely right to suggest that’s the right phrase. It’s incorrect though to say that the claim of settled science is only a straw man. It’s much more difficult than that.

    • WillR
      Posted Jan 20, 2010 at 5:37 PM | Permalink

      Steve: snip – OT

    • Richard Drake
      Posted Jan 20, 2010 at 5:58 PM | Permalink

      Nah, I’ve seen the films, it’s got to be a beautiful woman tied up on the line and they always get released in the nick of time. I’m on the roof dueling with Hansen and sure enough, the tunnel just came into sight.

      Meanwhile, your second para was just getting interesting when the last clause caused my parser to fail. Is the bug my end or yours?

Slabadang

This is obviously a “science” that has to return to basics!No castle is built on shaky grounds.

• Jeff Alberts
  Posted Jan 19, 2010 at 12:49 PM | Permalink

  “They said I was daft to build a castle in the swamp, but I built it all the same, just to show ’em. It sank into the swamp. So, I built a second one! That sank into the swamp. So I built a third one! That burned down, fell over, then sank into the swamp, but the fourth one stayed up!”

Julian Flood

* an increase in surface reflectivity (impossible since tropical ocean surface reflectivity doesn’t change with surface temperature)

Do coccolithophores respond to temperature with increased growth? If so they would substantially increase ocean albedo. Do higher SSTs lead to increased surface wind? If so, increased emissivity during darkness would provide a feedback in high latitudes. There is an interesting blip in windspeed to go with the SST blip from ’39 to ’45 that Wigley (?) complains about as inexplicable in the CRU emails.

* increase in aerosols that are making clouds more reflective with relatively small impact on IR emission (no major volcanoes during this period, but Saharan dust and biomass burning could have the desired effect. However, no known relationship between surface temperature and dust/biomass aerosols)

Does DMS production increase with increased temperature? Does the ocean flora manipulate the sea surface to increase salt particle production when temperatures threaten to rise too high? Does dust and dissolved silica alter the relative success of diatoms (relatively poor at DMS production) and coccolithophores? Does excess nitrate runoff lead to reduced Emiliana huxleyi populations as they succumb to viral infection?

* increase in low cloud amount (that reflects sunlight while emitting IR at nearly the same temperature of the surface). This works only if the increase in low cloud amount is not obscured by high clouds (which dominate the radiation fluxes at the top of the atmosphere when they are present). For this to be a significant effect, we would need to see a decrease in deep convective clouds in the tropics, which to my knowledge hasn’t been observed.

I find this surprising: my experience of low level oceanic stratocumulus is that it frequently occurs without higher cloud masking it.

Even more surprising is the limited attention given by climate science to the biology of the ocean surface. If it all turns out to be Emiliana huxleyi, it’ll be enough to make a diatom laugh.

JF

• Judith Curry
  Posted Jan 19, 2010 at 7:52 AM | Permalink

  Julian, good questions

  surface albedo: no idea about the cocco….. wind doesn’t influence the surface albedo in SW unless the sun angle is very low (however wind is a big deal in terms of microwave reflectivity which is important for remote sensing of the sea surface but not for energy balance)

  re aerosol particles and ocean biology: good question, an open topic for research

  re low cloud amount: abundant low clouds (without overlying high clouds) are found in the subtropics (not the tropics)

  The issue of upper ocean biology being involved in feedbacks is interesting. I personally have very little knowledge about this. My understanding is that over the small temperature changes we are talking about, the issue is in terms of productivity is nutrients rather than temperature. I would appreciate hearing more about your ideas on this.

  • Julian Flood
    Posted Jan 21, 2010 at 7:32 AM | Permalink

    Re surface albedo: I think emissivity is the crucial factor here. Ruffled water cools more quickly. If the water is smoothed for any reason, it will stay warmer during darkness. I’ve got a graph of it somewhere and I’ll try to find the reference.

    Re: aerosols: no sign of VOCALS yet.

    Re: stratocu: I didn’t know that.

    I now reveal the system of the world… well, part one.
    One of the more telling arguments for human involvement in climate change is the isotope record of C, but elevated C12 is essentially only a biological signal which says nothing about attribution. The assumption is sometimes — perhaps ‘often’ is not too strong here — made that the signal is from the past in the form of burnt fossil fuels. It is entirely possible that the isotopic signal is from the present.

    There is a nice graph in ‘Evidence for pre-industrial variations in the marine surface water carbonate system from coralline sponges, Böhm ea.’ (it can be found on Ferdinand Engelbeen’s site) which shows changes in the isotope ratio since 1400. This has been pointed to as evidence for fossil fuel burning: it is nothing of the sort. The ratio begins to change in 1700 and the fall correlates poorly with fossil fuel consumption (eyeball only which needs to be mathematically verified). There are other possible explanations for that graph, but research would be needed to eliminate those which do not match reality.

    The easy way for plants to fix carbon is the C3 process, a process which discriminates against the heavier carbon isotopes. C3 plants, land and sea, will preferentially pull C12 from the atmosphere. Any disturbance of this steady state will increase the C12/C13 ratio and will show up in the atmosphere as increased C12. In certain circumstances — low nutrient levels, lack of certain trace elements such as zinc and chromium, low CO2 levels — the C4 pathway is easier. Some phytos are obligate C3, some C4 and some can switch from one process to the other. C4 is much less discriminating between C isotopes, as is the Crassula Acid Mechanism (CAM).

    Diatoms use a C4-like process. They are ferocious competitors for nutrients, so much so that only when diatoms exhaust their own limiting nutrient, silica, do the calcareous phytos bloom. If dissolved silica in the productive zones around the continents has been increased by agricultural run-off and dust then the calcareous phytos will be at a disadvantage, switching when starved to C4, and the isotope signal will change accordingly. The populations of various diatom species will vary. The spectacular coccolithophores will be fewer and the oceanic albedo will drop. Google for images of Emiliania huxleyi blooms off Newfoundland to see how this coccolithophore reflects light upwards as it sinks — benefitting whatever plant is growing above it. It would be interesting to check the literature for the feeding habits of recently hatched codlings: an ideal ultimate theory of climate change would include the collapse of the cod fishery off Newfoundland*, and if silica increase changes the ecosystem to starve minute codlings it would be a gratifying bonus. I can find no measurements of the light levels inside and outside of phyto blooms.

    Pulses of dissolved silica and of inputs such as volcanic dust rich in zinc and chromium might show up in the record as changes in C12/C13. Aeolian dust, if it can be shown to dissolve, might be correlated with minor isotope variation. Global temperature changes silicate weathering rates and if that silicate goes into the deep oceans it will upwell in the southern ocean after some hundreds of years, changing the flora and with cause and effect separated by that lag. It might be possible to tie current silica levels to the MWP.

    The ooze should show the associated changes in phyto/diatom populations. A separate check on radiolarian populations might be useful as giving some handle on the levels of silica in blue water ocean areas. Silica levels in deep water should be interesting.

    It should be possible to test whether the flora of the ocean surface has been changing over the last 200 years. If C4, C4-like and CAM metabolism has become more common then we can speculate that there will be other implications, not merely changes in isotope fluxes. Obvious examples are DMS production, carbon export to the deep ocean, albedo and surface effects.

    If biology is providing climate feedbacks, the isotope signal will give us clues about how the biology is changing and how this will alter its ability to drive those feedbacks.

    I will now go away and think.

    JF

    *any truly global theory should be overly ambitious.

  • willis Eschenbach
    Posted Jan 21, 2010 at 11:09 PM | Permalink

    Judith Curry, thanks as always for your comments and insights. You say:

    Posted Jan 19, 2010 at 7:52 AM | Permalink | Reply
    Julian, good questions

    surface albedo: no idea about the cocco….. wind doesn’t influence the surface albedo in SW unless the sun angle is very low (however wind is a big deal in terms of microwave reflectivity which is important for remote sensing of the sea surface but not for energy balance)

    While wind does not change the surface albedo in SW, it definitely changes the surface area. This is because as soon as you get spray, you have a huge number of tiny droplets, each of which has a surface which is radiating …

    re low cloud amount: abundant low clouds (without overlying high clouds) are found in the subtropics (not the tropics)

    As someone who has lived in the tropics for years, I can assure you that you are wrong. The tropics generally have low clouds from about 11AM onwards. If the ocean is warm enough, some of them turn into thunderstorms and high clouds … but the rest are still there.

    So if the (low) clouds form at say 10:00 rather than 11:00, this makes a very large and significant change in the energy balance. Despite Julian’s claim, this can easily occur with no change in the amount of high clouds, I see it all the time.

    This is a very large unrecognized problem in climate science, which is that averages aren’t enough. For example, generally tropical clouds are around from about 11 AM to 11 PM. My figures show that if this shifts forward by one hour, it makes about a 4 W/m2 difference in the radiation balance … but the average amount of clouds hasn’t changed at all. The only thing changed is the timing.

    The issue of upper ocean biology being involved in feedbacks is interesting. I personally have very little knowledge about this. My understanding is that over the small temperature changes we are talking about, the issue is in terms of productivity is nutrients rather than temperature. I would appreciate hearing more about your ideas on this.

    One of the more fascinating finds in the last few years is that plankton emit gas with sulfur containing compounds when they get heat stressed. These sulfur compounds serve as cloud nuclei, and thus tend to cool the plankton down … how big is that effect? No one knows, but given the area of the ocean, it could be quite large. Haven’t noticed any models incorporating it, though … and it’s a negative feedback. Coincidence? You be the judge …

    w.

    • Julian Flood
      Posted Jan 22, 2010 at 2:25 AM | Permalink

      Willis,

      I made no claim about tropical stratocu — it was a repeat of Dr Curry’s comment above. VOCALS experiments should be complete by now and no doubt they are analysing the results of flying through the continent-sized low level cloud off Chile.

      Yes, thanks for emphasising that emissivity is the point of wind effects on the ocean surface — a smoothed ocean will cool at a slower rate than a ruffled one during darkness.

      In answer to Dr Curry’s request, I posted a rather long part one reply which seems to have vanished into the ether, Knowing our host’s dislike of speculation, I am reluctant to post again with part two ramblings added — one does so dislike one’s pearls being snipped. The dilemma is, of course, having to choose between rudeness to our host or his guest.

      In a nutshell — manipulation of cloud salt particle size by changes to the ocean ‘skin’ with surfactants and lipids, manipulation of the number of CCNs by DMS, manipulation of the physics of cloud droplets by oil or surfactant. This gives the ocean flora the ability to increase or decrease cloud cover, controlling temperature, UV and light levels. Underwater control of light can be achieved by use of coccolithophore platelets. Long term changes in the populations by e.g. replacement of calcareous phytos by silicaceous diatoms (hence the low C isotope signal) will show up as a changed steady state position. Radiolarian shells (silica) have been atrophying for 3 million years and perhaps we have reversed that decline.

      JF

    • Julian Flood
      Posted Jan 22, 2010 at 12:24 PM | Permalink

      Interesting, my long post came, went, recame and has now gone again. Is there a Connelly in the house?

      JF

    • Judith Curry
      Posted Jan 24, 2010 at 7:47 AM | Permalink

      Willis, a comment about the low clouds. In the tropics, these are shallow cumulus, typically with an areal coverage that is typically less than 20%. this dilutes the radiative impact of these clouds relative to say the extensive sheets of low level stratocumulus in the subtropics.
      You make an interesting point about the diurnal cycle. The ISCCP dataset does include diurnal cycle information on clouds (with 3 hour resolution), and could be use to look at any impacts from the diurnal cycle of cloudiness.

Ivan

Curry: “Colin, the “science is settled” is political statement, not a scientific statement! Decision making under uncertainty is often done facing conditions of much greater uncertainty than say the IPCC report. Even the IPCC report gives probabilities for its conclusions (none reach 100%, although they do say that warming in the latter half of the 20th century is “unequivocal”)”

That warming was “unequivocal” since 1975-76 until about 2000 nobody would deny. However, nobody would deny that there was unequivocal cooling 1945-1975 either.

When AGW alarmists (IPCC included) say that “science is settled’ what they mean by that is not that nobody denies that there was a warming in recent decades, but that nobody denies that man was a cause of that warming, and that warming will get worse due to the man in the future, and that this will have catastrophic consequences. So, we don’t have here only a non-controversial factual statement as you suggest, but a very complex and entirely unsubstantiated chain of reasoning which is sold and advertised to the public as “rigorous argument” using the authority of governmental and intergovernmental bodies. The debate on feedbacks here just highlights the problems in one of the many unsubstantiated leaps in that “argument”.

In that regard, your response to Colin was a classic red herring.

• Judith Curry
  Posted Jan 19, 2010 at 6:16 PM | Permalink

  The IPCC statement says that “most of the warming in the latter half of the 20th century is very likely caused by humans”. “most” implies greater than 50%, and “very likely” means > 90% as defined by IPCC. Do I agree with the combination of 50% and 90% in this statement? No. At least some of the warming is caused by anthropogenic CO2 (no one argues with that), exactly how much requires sorting out all the causes of natural variability. In the 90’s, the warm temperatures got a boost from warm phases of both AMO and PDO (the same thing that i think caused the bump ca 1940).

  • geo
    Posted Jan 19, 2010 at 6:31 PM | Permalink

    Yes, I think a lot of us sense that IPCC took “worst case” and passed it off as “middle of the road” and then tried to shout everybody else down.

    Re AMO and PDO. . . would you agree that we’re likely going to have a relatively firm grip in say, about 10 years, as to what the real future temperature trend line is liable to look like?

    • Judith Curry
      Posted Jan 19, 2010 at 8:02 PM | Permalink

      10 more years of data (plus model improvements) will certainly help us sort all this out.

blueice2hotsea

May I?

Winter NH warming would be an expected fingerprint of CO2 induced warming because both water vapor and methane, which are abundant GHGs in the summer, plummet in the winter, leaving CO2 dominant.

So, a change in CO2 will have a much more noticeable effect on surface temperature than say in the summer ocean tropics where as JC has already noted, “virtually no IR emitted by the surface reaches space”.

Also, temp swings over land are more pronounced than over the oceans; the NH has more land than the SH.

• Judith Curry
  Posted Jan 19, 2010 at 8:21 PM | Permalink

  A quick reply to the Arctic vs Antarctic situation. A new report has been put out by the British Antarctic Survey that is relevant here
  http://www.antarctica.ac.uk/press/press_releases/press_release.php?id=1065

  • Lance
    Posted Jan 19, 2010 at 9:47 PM | Permalink

    Dr. Curry,

    Doesn’t the idea of using one unproven climate theory (the CFC’s depleting the ozone hole) to explain the failing of another (the lack of AGW warming in the Antarctic) seem a bit precious?

    Talk about layering uncertainties onto uncertainties!

    Wouldn’t it be more consistent and honest just to admit that the lack of warming in the Antarctic is inconsistent with AGW and say that we don’t understand why?

    Using the alleged build up of CFC’s(which are supposed to be anthropogenic greenhouse warming gases anyway) in the stratosphere as an ad hoc excuse for the lack of expected warming looks like a desperate attempt to explain a blatant empirical inconsistency with AGW theory and its attendant “polar amplification”.

    The best scientists I know are not afraid to say “Gee, I don’t really know what happened there. Maybe we should rethink things a bit.”

    • Judith Curry
      Posted Jan 20, 2010 at 5:16 PM | Permalink

      Lance, regardless of what is causing the antarctic ozone to be depleted, its depletion is a robust observation, and the depletion does impact the greenhouse effect in this region, particularly because there is low water vapor in this region

    • schnoerkelman
      Posted Jan 21, 2010 at 7:55 AM | Permalink

      Re: Judith Curry (Jan 20 17:16),
      I’m sorry if this is OT but since it was being discussed…

      As I understand it ozone depletion takes place when temperatures are very low, that is Antarctic winter with virtually no insolation. Given the low temperatures I would think that IR emission would also be reduced and thus the role of GHGs reduced in turn.

      Could you perhaps clarify this or provide a link?
      Thanks, bob

    • DeWitt Payne
      Posted Jan 22, 2010 at 3:35 PM | Permalink

      Re: Judith Curry (Jan 20 17:16),

      …the [ozone] depletion does impact the greenhouse effect in this region….

      Indeed. Quick and dirty MODTRAN calculation using SubArctic Winter conditions. Setting stratospheric ozone scale to zero increases LW TOA emission by about 4 W/m2, or about twice the radiative effect at that latitude of doubling CO2, and in the opposite direction. The surface temperature offset required to restore balance is about -1 C. What’s not included in MODTRAN, however, is the change in stratospheric temperature, which in the absence of sunlight, would warm because less energy is being radiated away by the ozone.

      In reply to another comment above:

      Upper tropospheric warming in the tropics is not a fingerprint only of enhanced greenhouse warming. Any warming of the surface should, to a first order, cause enhanced warming of the upper troposphere compared to the surface. Over a short term, it does. A lack of observed enhanced upper troposphere warming over the long term in the tropics, however, may be a test of model validity, the surface temperature record or the upper tropospheric temperature record or some combination of all three.

  • blueice2hotsea
    Posted Jan 22, 2010 at 11:15 AM | Permalink

    Dr. Curry, thanks for that link.

    Antarctic cooling caused by CFC reduction(!), a good reason not to expect a CO2 fingerprint there.

    But, now I am bothered by the image that we are like the heat-stressed plankton mentioned by W.Eisenbach, which blithely moderate a more favorable climate through gas emissions. Remember when global cooling and looming food shortages were big concerns? We coincidently reduced CFC’s, scrubbed power plant SO2 and expanded methane producing wetlands. And now, a warmer, greener planet.

Waterloo

First, let me state that Dr. Curry is clearly a person of science. Science relies on addressing counter claims, devising experiments and tests, and producing verifiable results, and Dr. Curry clearly shares that philosophy.

Now, for my question As a control (feedback) Engineer, one of the must troubling things that I see is the use of the term “climate sensitivity” to mean the sensitivity of climate to a change in CO2, and, in fact, taking it a step further and using it as the linear response to a doubling of CO2. From my point of view, this is a horrible misleading use of the term sensitivity, which should be the change in the output to an infinitesimal change in the parameter (ie, the norm of the partial derivative of the model to the parameter in question). This, IMHO, missuse of the term sensitivity makes me extremely concerned if proper sensitivity analysis are being done on the other parameters used in climate models. So Dr. Curry, why was the term sensitivity used in this way, and are climate models subjected to proper sensitivity analysis?

• RB
  Posted Jan 19, 2010 at 6:08 PM | Permalink

  Actually, doesn’t the sensitivity as known to climate science go as 4.3 ln(C/C0) – definitely not linear.

  • Henry
    Posted Jan 19, 2010 at 7:47 PM | Permalink

    There is no certainty over the 4.3 factor (which corresponds to a 3°C increase for a doubling of the CO2 concentration). It might instead correspond to 1°C, 2°C or 4°C; this uncertainty would have a dramatic impact on the possible cost of adaptation.

    There does appear to be a consensus that the relationship is logarithmic (so the marginal sensistivity falls inversely as concentrations increase), even though concentrations of other greenhouse gases such as methane are thought to have different non-linear relationships with temperature. To me the lack of a single relationship function across different gases could cast doubt on the certainty of each of the asserted relationships.

    • RB
      Posted Jan 19, 2010 at 8:02 PM | Permalink

      Yes, I should have stated it as most likely value – I was just pointing out the log relationship. The 4.3 will be 4.3+/-2.15 I suppose.

    • RB
      Posted Jan 19, 2010 at 8:06 PM | Permalink

      Strictly speaking I guess it should probably be described by a distribution as done here .

    • Henry
      Posted Jan 20, 2010 at 7:42 AM | Permalink

      I think your link broke and you were aiming for Annan and Hargreaves, Using multiple observationally-based constraints to estimate climate sensitivity, which looked at the unlikelihood of high sensitivities

    • RB
      Posted Jan 20, 2010 at 9:28 AM | Permalink

      Thanks for correcting that.

    • RB
      Posted Jan 20, 2010 at 10:25 AM | Permalink

      BTW, notice how the most likely value in the above coincided with Hansen’s number of 2.8C per doubling based on different evidence.

    • RB
      Posted Jan 19, 2010 at 9:13 PM | Permalink

      Hansen’s case for the sensitivity of CO2 at 2.8C per doubling is nailed .

• Judith Curry
  Posted Jan 19, 2010 at 6:10 PM | Permalink

  Waterloo, I agree totally! this is a misuse of the term sensitivity in terms of its meaning in the context of control theory. Back in the 1970’s, a few scientists applied linear control theory to a simple global energy balance model, and derived a sensitivity parameter that is essentially delta radiative flux at the top of atmosphere/delta surface temperature. Most of my essay is about why i don’t think this is really “sensitivity” in the context of a real feedback analysis. Your suggestions on a better way of doing things would be appreciated!

• RB
  Posted Jan 21, 2010 at 4:39 PM | Permalink

  This was the book chapter I was referring to in the above.

• bstewart
  Posted Jan 21, 2010 at 4:44 PM | Permalink

  BLouis79 might be referring to the fact that in any ensemble of GCM runs that ought to reach a steady state, some do and some run away to unrealistic conditions. (By runs that ought to reach steady state, I mean for example no CO2 increase, or increase CO2 until it doubles and then hold CO2 at the new level.) It is (or used to be) common practice to toss the realizations that run away, without any understanding of why those particular realizations misbehaved and others didn’t. Flux corrections aim to reduce these misbehaviors, but don’t entirely eliminate them. Do I have that right?

  • BLouis79
    Posted Jan 26, 2010 at 4:18 PM | Permalink

    It is likely that (erroneous)positive feedbacks cause unstable models.

    Errors in cloud modelling are sources of large potential errors according to IPCC AR4-WG1-Ch2 and IGBP report No 58 http://www.igbp.net/documents/resources/Report_58.pdf

    Superparameterization is suggested by IGBP as a fix. Interesting that the first report of a GCM+superparameterized could model demonstrates negative cloud feedback in response to sea surface warming (Wyant et al)
    ftp://eos.atmos.washington.edu/pub/breth/papers/2006/SPGRL.pdf

H Hak

A bit OT, but interesting quote
“Looking back at the worst times, it always seems that they were times in which there were people who believed with absolute faith and absolute dogmatism in something. And they were so serious in this matter that they insisted that the rest of the world agree with them. And then they would do things that were directly inconsistent with their own beliefs in order to maintain that what they said was true.” —The Meaning Of It All: Thoughts of a Citizen-Scientist, 1998
Richard Feynman

H. Tuuri

I analyzed the ERBE tropics data with a free statistics program called OpenStat and posted the results as a comment on realclimate.org. I used a different smoothing approach than LC09, but I was able to repeat the main result of Lindzen and Choi: the climate sensitivity of the tropics is lower than for a black body.

OpenStat also tells us that there is essentially no correlation of tropical sea surface temperature anomaly to the heat transfer from the tropics to higher latitudes. That suggests that we cannot use El Nino to measure the climate sensitivity of higher latitudes. But, since the tropics comprise roughly 1/3 of the surface area of Earth, their impact to the global climate sensitivity is significant.

As to the impact of a doubling of CO2 in high Northern latitudes, I think the temperature rise here has stopped since 2001. Maybe the fast rise in 1980-2000 was just a fluke, and the climate sensitivity is not that high, after all?

DeWitt Payne

The forcing from 2X CO2 is higher in the tropics than at high latitudes as this figure from Hansen, et.al., 2005 shows. The reason is that the altitude of the tropopause is higher in the tropics because the lower atmosphere is warmer and less dense so the temperature difference between the surface and the altitude where the optical depth of the CO2 band becomes less than one is larger. That significantly increases the total forcing from CO2 in the tropics compared to high latitudes. Since the total forcing from CO2 is lower at high latitudes, the magnitude of the change in forcing from doubling is smaller too. You can see the difference for yourself by playing with the numbers on Archer’s MODTRAN page.

• Gerald Browning
  Posted Jan 20, 2010 at 1:15 AM | Permalink

  Dewitt,

  If I understand you correctly, your arguments support the neglect of the extratropics in the Lindzen Choi manuscript?

  I find it amusing that a 6 page manuscript with some simple mathematical equations and observational data has caused such an uproar among the AGW proponents. A bit embarassing for them, especially if Lindzen addresses the
  criticisms in his followon manuscript.

  Jerry

  • DeWitt Payne
    Posted Jan 20, 2010 at 11:10 AM | Permalink

    Re: Gerald Browning (Jan 20 01:15),

    Jerry,

    Several comments in this thread repeated the argument that warming from CO2 is greater at high latitudes because there’s less water vapor. That’s wrong. It also has nothing to do with whether restricting the analysis to the tropics is justifiable. While forcing is highest in the tropics, sensitivity, in terms of surface temperature, is very likely lowest. Much of the excess heat will be transferred to the higher latitudes and, assuming that relative humidity remains approximately constant in the planetary boundary layer in the tropics, most of the retained heat should be latent not sensible.

    The global map in my link above also shows why expansion of equatorial and mid-latitude desert area may be self limiting in a warmer world. If you look at Africa, there’s what amounts to a hole in the forcing over the Sahara. Very low humidity means more efficient radiation of heat from the surface to space.

    • DeWitt Payne
      Posted Jan 20, 2010 at 11:22 AM | Permalink

      Re: DeWitt Payne (Jan 20 11:10),

      Oops. I should have looked at the chart again before I posted. I remembered the hole in Africa, but the location was incorrect. It seems to be related to the ITCZ and regions of high rates of upwelling.

    • Gerald Browning
      Posted Jan 20, 2010 at 1:33 PM | Permalink

      Dewitt,

      The latent heat forcing in the tropics (and hence SST that generates the water vapor in the atmosphere) is a dominant
      component of the forcing in the tropics and the convective heat towers rise to much higher altitudes than in the midlatitudes. The dominance of the net heating of this type is restricted to the equatorial region and smaller scales in the modlatitudes.

      Jerry

• Judith Curry
  Posted Jan 20, 2010 at 7:05 AM | Permalink

  DeWitt, forcing is not sensitivity (nor is it feedback). the sensitivity of interest is the change of global surface temperature to a change in external forcing (e.g. increasing CO2). What is going on in the upper tropical troposphere is obviously important for the top of atmosphere radiative forcing, but it is not particularly important for the global sensitivity.

  • Gord Richens
    Posted Jan 20, 2010 at 7:52 AM | Permalink

    Hmm. So the two need not be consistent?

  • bender
    Posted Jan 20, 2010 at 10:05 AM | Permalink

    What is going on in the upper tropical troposphere is obviously important for the top of atmosphere radiative forcing, but it is not particularly important for the global sensitivity.

    First, this is an assertion. Do you plan on defending it?
    .
    Second, I think DWP’s point could be rephrased as follows. If one were going to bias a study such as L&C’s by focusing on just one part of the world, you’d choose exactly the part of the world that they chose: tropical. Other parts of the world (extratropical, polar) would lead to an even larger extrapolation problem of the sort JC has in mind. Sure, an unbiased analysis would be better. Sure, it would be nice to replicate it in different parts of the globe. Sure, it would be preferable if L&C didn’t go out on a limb with speculative conclusions.
    .
    Third, tropical is not entirely divorced from extra-tropical. So I would be careful how hard I pushed that argument. That ENSO and PDO are “orthogonal” is an algebraic trick and does not imply functional (dynamic) independence. I’ll see if I can find that map that showed up a few months ago which suggested a ~2 year delay between ENSO & PDO warm anomalies. There was not a lot of commentary on it at the time. Just David Smith and a couple of others. But it made the point that tropical heat can be lost to the atmosphere directly (within the tropics) or moved poleward with some time delay and THEN lost to the atmosphere. Again, this does not mean that L&C’s extyrapolation is justified. It just mitigates some of the damage inflicted by JC’s extrapolation argument.

    • See - owe to Rich
      Posted Jan 20, 2010 at 3:28 PM | Permalink

      Hi Bender,

      In your #3 you forgot my name. Still, I won’t take it personally, and help you by pointing to
      https://climateaudit.org/2009/05/12/unthreaded-n2/#comment-183534 which I had bookmarked, following which there were comments by you and me on estimating the time lag. Unfortunately, the graph itself isn’t actually there, but there is a pointer to Bob Tisdale’s.

      HTH,
      Rich.

    • bender
      Posted Jan 20, 2010 at 10:13 PM | Permalink

      Thank you. That was it. You were in my “et al”, but I couldn’t put my finger on exactly who it was. It’s your handle. I don’t think of you as “Rich”. You’re so much more!

    • Judith Curry
      Posted Jan 20, 2010 at 5:12 PM | Permalink

      The importance of the tropical upper troposphere for TOA radiative forcing is indicated in the Hansen 2005 graph provided earlier.

      If sensitivity is defined as delta surface temperature/delta CO2 concentration, then the plots of observed and modeled surface temperature change reflect the local sensitivity

      Regional sensitivity is a dodgy thing to try to determine. See figure 12.5 from my book which can be found at http://curry.eas.gatech.edu/Courses/6140/lectures.html (look at lecture 12) which describes the average zonal energy transport

    • ianl8888
      Posted Jan 21, 2010 at 1:48 PM | Permalink

      Steve – snip. Too general an issue. Insufficiently connected to post specifics.

    • D. Patterson
      Posted Jan 22, 2010 at 5:19 AM | Permalink

      What is going on in the upper tropical troposphere is obviously important for the top of atmosphere radiative forcing, but it is not particularly important for the global sensitivity.
      [….]
      The importance of the tropical upper troposphere for TOA radiative forcing is indicated in the Hansen 2005 graph provided earlier.

      Absent from those sources is a recognition of the asymmetric forcings associated with the tropical Hadley circulation and their effects upon extratropical sensitivities as described in the modeling experiments by Yoshimori, Broccoli, and others preceding them. Although the authors acknowledge Chiang and Bitz [2005] were unable to find a confirmation of the modeled results in the observational record of the interhemispheric records, this problem once more highlights the potential perils of relying upon parameterizations and GCM results which are not adequately confirmed by the observational records.

      Have you considered the results of Yoshimori and Broccoli [2009] when asserting TOA is not particularly important for the global sensitivity?

      Yoshimori, M., and A. J. Broccoli (2009), On the link between Hadley circulation changes and radiative feedback processes, Geophys. Res. Lett., 36, L20703, doi:10.1029/2009GL040488.

    • Ryan O
      Posted Jan 21, 2010 at 3:06 PM | Permalink

      Bender,

      I bet you’ve already seen this, but for other interested readers, this would provide background for your #3. As you pointed out, many of the observed “teleconnections” and “orthogonal” modes interpreted from temperature or pressure time series are likely to be statistical artifacts. That means the observed independence of ENSO/PDO are also artifacts, and ENSO/PDO (and NAM/SAM) do not necessarily have physical meaning. I agree wholeheartedly that this weakens the extrapolation argument. However, L&C still have the burden of proof to show that the extrapolation is valid, as they are the ones making the claim that their analysis can be used to determine global sensitivity.

      Anyway, as far as the artifacting goes, one of the best references I’ve found is here:

      Click to access ijc-compagnuccirichman.pdf

      A must read for anyone who believes these indices are physical phenomenon. Most will fail the test in the above (and fail badly).

Leo G

Where does one look to find the global average temp if our atmosphere contained no CO2?

I am trying to help my son with a geography project.

(You don’t want the old man to look stoopid do you?)

🙂

• oneuniverse
  Posted Jan 21, 2010 at 6:12 AM | Permalink

  Re: Leo G (Jan 20 01:31),

  Hi Leo,

  The figure I’ve heard most often is that the greenhouse effect as it stands now contributes roughly 30 degrees of warming to the climate. I don’t think that figure is derived from first principles, though.

  There’s an article at Roy Spencer’s site, discussing how things might be on Earth if there were no greenhouse gases present. I’m not sure if it answers your question about temperature, though – haven’t read it entirely.
  http://www.drroyspencer.com/2009/12/what-if-there-was-no-greenhouse-effect/

ianl8888

Judith Curry

I’ve been looking forward to this for some time – your courage in participating in open debate is to be admired, because the closed Peer Review system is simply too difficult for non-climate scientists to access in any timely or sequential fashion

I’m only a geologist, so although core science is OK for me, understanding the nuances in this thread will take me some time … I do not at all begrudge this time, however

But there is one irritation that is unhappily far too repetitively familiar. Apparently Lindzen & Choi have published (?) an extension, addition, rebuttal or whatever. The irritation (and way too much of a constant) is that we do not have this to inform us further. So we simply go on shadow boxing. If you have access, could you please post a link ?

• Judith Curry
  Posted Jan 20, 2010 at 6:58 AM | Permalink

  Ian, I haven’t seen his new paper yet either, unfortunately, apparently it is under review and it is not posted at Lindzen’s web site. I agree that peer review process is too slow, but i also understand why scientists don’t publicly post their papers until they are accepted for publication. Assuming that LC again submitted their paper to GRL, GRL is pretty quick at getting papers reviewed and published.

  • ianl8888
    Posted Jan 20, 2010 at 7:10 AM | Permalink

    Thank you for the reply

    Shadow boxing … at least the delay may give me time to absorb the different points of view up to this time

TG

JC said: […i also understand why scientists don’t publicly post their papers until they are accepted for publication…]

It is interesting, however, that physics, math and some other communities have no problem with posting preprints on http://arXiv.org; I believe the case is even stronger for climate science community to do likewise.

• Richard Drake
  Posted Jan 20, 2010 at 9:44 AM | Permalink

  Another aspect to the openness appropriate to the very unusual situation of climate science. IT acting as blessing as well as curse (as it is in over-hyped GCMs, for example) – very fitting. I totally agree.

• Judith Curry
  Posted Jan 23, 2010 at 7:55 AM | Permalink

  TG I totally agree. But when a topic is highly politicized, scientists are worried about a massive letter writing campaign that might result in a withdrawal from publication of an in press article. Think M&M, Soon and Baliunas, etc.

  • Richard Drake
    Posted Jan 23, 2010 at 9:17 AM | Permalink

    You are talking in the two examples given of a letter writing campaign from those trying to protect AGW ‘orthodoxy’ by getting certain papers withdrawn from publication. But if preprints had been available on http://arXiv.org – if this was an accepted part of the culture in climate science, as it is in maths and physics – surely this would have served to deter such a letter writing campaign? Is there a downside therefore? Isn’t this something to campaign for as part of an Open Climate Initiative (as I will call it until my elders and betters tell me different) – putting right at least some of what went wrong as revealed in the CRUtape letters?

    • Judith Curry
      Posted Jan 24, 2010 at 7:31 AM | Permalink

      Richard, I personally agree with you. If everything was open, progress would be more rapid and letter writing campaigns would be public for all to assess. How to change the culture is not simple. If any of you are AGU members, consider voting for Peter Webster for the AGU section president on Atmospheric Science, who is campaigning for more transparency and openness in climate research
      http://www.agu.org/elections/ballot/atmos.shtml#pwebster

    • Richard Drake
      Posted Jan 24, 2010 at 11:01 AM | Permalink

      Thanks very much for that link to Peter Webster. I don’t have a vote myself so the reply is mostly to highlight this for AGU members that might miss it. Go for it, my geoscience friends. A group of you put me, a little IT guy, onto a more intelligent path on AGW in Bristol around 1992. Now, please sort it.

David Longinotti

I admire the expertise displayed here on the question of the sensitivity of the climate to CO2 but, if the goal is to understand the reason for the apparent rise in late 20th century global temperature, the effort seems to be misspent.

A good scientific theory accounts for past observations and has predictive value. The hypothesis that the climate is quite sensitive to CO2 seems to be a failed theory on both counts. It fails to explain the MWP, and it’s previous predictions of significant warming due to increases in atmospheric CO2 have proved false over the last 15 years.

If there is doubt about the MWP evidence (as summarized in papers like that of Mr. Loehle), or if there are hypotheses as to why CO2 effects have been ‘masked’ for the past 15 years, then I think that’s where the debate needs to begin. Without agreement on the main data that needs to be explained by the model, how can different models be reasonably evaluated?

Jim

Judith,

you said “an increase in surface reflectivity (impossible since tropical ocean surface reflectivity doesn’t change with surface temperature)”. Do you know this for a real-world fact? Surface reflectivity can be affected by bubbles or coatings, such as oil or protein. The sea contains life, and, temperature may alter the contents of the ocean resulting in a change in reflectivity. So, is that an observation or an inference?

• Judith Curry
  Posted Jan 21, 2010 at 6:56 AM | Permalink

  Could it change? Conceivably. Has it changed over the period that LC have looked at the data? No evidence to support this.

  • Gerald Browning
    Posted Jan 21, 2010 at 4:02 PM | Permalink

    Judith,

    Please cite reference that there has been no change instead of guessing.

    Jerry

    • Judith Curry
      Posted Jan 23, 2010 at 7:51 AM | Permalink

      Jerry, go to google scholar, google ocean surface reflectance temperature and see what pops up. Alot of stuff about remote sensing of the ocean surface in the microwave. My statement “There is no evidence to support . . .” means exactly that. No one is writing papers on this, there is no obvious physical mechanism for this. If you would like to do the analysis yourself, more than 25 years of global ocean surface albedo data (from satellite) is available from ISCCP
      http://isccp.giss.nasa.gov/products/products.html

• BLouis79
  Posted Jan 21, 2010 at 2:39 PM | Permalink

  snip – OT for Lindzen and Choi

Frank

Judith and Steve: If we are ever fortunate enough to have commentary on another controversial paper from Judith, could you consider breaking the commentary up into multiple posts on narrower topics? I have returned to this post, the RC post, the LC paper and some of the references several times since it appeared digesting the arguments and hoping to formulate an intelligent question or comment that reflects something more than pre-conceived bias. Multiple posts on narrower topics might convey more information and promote more intelligent discussion.

Dave F

Isn’t it possible that climate sensitivity isn’t a static number?

• Dave F
  Posted Jan 22, 2010 at 12:15 PM | Permalink

  I mean that something, like cloud cover, could actually affect the sensitivity number instead of being represented as its own forcing. Or is this a silly question?

  • Richard Drake
    Posted Jan 22, 2010 at 1:48 PM | Permalink

    snip – enough chaos

Judith Curry

I’ve gone back through the comments and posted a number of new comments to many of the threads. I’m not sure how to view the most recently posted comments, but i will continue to browse the threads for a few more days to see if there is further interest. Thanks to all of you for your comments!

Rob Mitchell

Hi Judith, I’m Not sure if anyone mentioned it in comments but surely the mechanism of shortwave negative feedback is the timing of thunderstorm development during the day. Higher SST result in earlier thunderstorms resulting in increased albedo. Of course this is a tropics only mechanism.
Cheers

• Judith Curry
  Posted Jan 24, 2010 at 6:53 PM | Permalink

  Rob, thanks for your comment. Willis Eschenbach did mention the issue of cloud diurnal cycle, this is a possible mechanism.

Alex Heyworth

Judith Curry (Jan 19 18:47), Judith, you said you found George White’s web paper interesting and were going to look at it in detail. Be very interested to know your view once you’ve had that opportunity.

David Weisman

I’ve been rereading the abstract and some of the discussion of Lindzen and Choi 2009. While many people have discussed the statistics itself, I’m still struggling with what they wanted to prove about climate sensitivity. Many scientists now believe the ice ages coincide with tiny orbital variations, but it took awhile to come up with the idea because the change in energy received by the Earth between ice ages and interglacials is minute. It seems the global temperature must be fairly sensitive to some stimuli over longer time scales – unless someone has posited a much more drastic forcing to explain the alternation between ice ages and interglacials.

Others have suggested changes in the sun could explain terrestrial temperature variation – but the actual energy variation in the sun seems to be small, so we have the same problem – if we try and postulate a low climate sensitivity.

It seems we may need a low sensitivity to certain things combined with a high sensitivity to others. Any ideas how this might work?