Responses to Gavin Schmidt, Part 2

OK, we continue to the final paragraph of Gavin Schmidt’s postadmitting a minor error in the October GISS numbers, and then proceeding to say that all the folks who pointed out the error are biased and unhelpful, in spite of the fact (or maybe because of the fact) that they found this error.

As I reviewed in part 1, most of the letter was just sort of petulant bad grace.  But this paragraph was worrisome, and I want to deal with it in more depth:

Which brings me to my last point, the role of models. It is clear that many of the temperature watchers are doing so in order to show that the IPCC-class models are wrong in their projections. However, the direct approach of downloading those models, running them and looking for flaws is clearly either too onerous or too boring. Even downloading the output (from here or here) is eschewed in favour of firing off Freedom of Information Act requests for data already publicly available – very odd. For another example, despite a few comments about the lack of sufficient comments in the GISS ModelE code (a complaint I also often make), I am unaware of anyone actually independently finding any errors in the publicly available Feb 2004 version (and I know there are a few). Instead, the anti-model crowd focuses on the minor issues that crop up every now and again in real-time data processing hoping that, by proxy, they’ll find a problem with the models.

I say good luck to them. They’ll need it.

Since when has direct comparison of forecast models against observation and measurement been the wrong way to validate or invalidate the forecast or model? I am sure there were lots of guys who went through the Principia Mathematica and tore apart the math and equations to make sure they balanced, but most of the validation consisted of making observations of celestial bodies to see if their motion fit the predicted results.  When Einstein said time would change pace in a gravity well, scientists took atomic clocks up in high-altitude airplanes to see if his predictions matched measured results.  And physicists can play with models and equations all day, but nothing they do with the math will be as powerful as finding a Higgs Boson at the LHC.

Look, unlike some of the commenters Schmidt quoted, there is no reason to distrust a guy because his staff made a data error.  But I think there is a big freaking reason to distrust someone who gets huffy that people are using actual data measurements to test his prediction models.

There is probably a reason for Schmidt to be sensitive here.  We know that Hansen’s 1988 forecasts don’t validate at all against actual data from the last 20 years (below uses the Hansen A case from his Congressional testimony, the case which most closely matches actual CO2 production since the speech).

gavin_forecast

More recent forecasts obviously have had less time to validate.  Many outsiders have found that current temperatures fall outside of the predicted range of the IPCC forecasts, and those that have found temperatures within the error bars of the forecasts have generally done so by combining large error bars, white noise, and various smoothing approaches to just eek actual temperatures into the outer molecular layers of the bottom edge of the forecast band.

As to the rest, I am not sure Schmidt knows who has and has not poked around in the innards of the models – has he studied all the referrer logs for their web sites?  But to some extent this is beside the point.  Those of us who have a lot of modeling experience in complex systems (my experience is in both econometrics and in mechanical control systems) distrust models and would not get any warm fuzzies from poking around in their innards.  Every modeler of chaotic systems knows that it is perfectly possible to string together all sorts of logically sound and reasonable assumptions and algorithms only to find that the whole mass of them combined spits out a meaningless mess.  Besides, there are, what, 60 of these things?  More?  I could spend 6 months ripping the guts out of one of them only to have Schmidt then say, well there are 59 others.  That one does not really affect anything.  I mean, can’t you just see it — it would be entirely equivalent to the reaction every time an error or problem measurement station is found in the GISS data set.  I am sure Schmidt would love us all to go off on some wild goose chase in the innards of a few climate models and relent on comparing the output of those models against actual temperatures.

No, I am perfectly happy to accept the IPCC’s summary of these models and test this unified prediction against history.  I am sure that no matter what temperature it is this month, some model somewhere in the world came close.  But how does that help, unless it turns out that it is the same model that is right month after month, and then I might get excited someone was on to something.  But just saying current temperatures fall into a range where some model predicts it just says that there is a lot of disagreement among the models, and in turn raises my doubts about the models.

The last sentence of Schmidt’s paragraph is just plain wrong.  I have never seen anyone who is out there really digging into this stuff (and not just tossing in comments) who has said that errors in the GISS temperature anomaly number imply the models are wrong, except of course to the extent that the models are calibrated to an incorrect number.  Most everyone who looks at this stuff skeptically understand that the issues with the GISS temperature metric are very different than issues with the models.

In a nutshell, skeptics are concerned with the GISS temperature numbers because of the signal to noise problem, and a skepticism that the GISS has really hit on algorithms that can, blind to station configuration, correct for biases and errors in the data.  I have always felt that rather than eliminate biases, the gridcell approach simply spreads them around like peanut butter.

My concern with the climate models is completely different.  I won’t go into them all, but they include:

  • the inherent impossibility of modeling such a chaotic system
  • scientists assume CO2 drives temperatures, so the models they build unsurprisingly result in CO2 driving temperature
  • modelers assume WAY too much positive feedback.  No reasonable person, if they step back from it, should really be able to assume so much positive feedback in a long-term stable system
  • When projected backwards, modeler’s assumptions imply far more warming than we have experienced, and it takes heroic assumptions and tweaks and plugs to make the models back-cast reasonably well.
  • Its insane to ignore changes in solar output, and/or to assume that the sun over the last 40 years has been in a declining cycle
  • Many models, by their own admission, omit critical natural cycles like ENSO/PDO.

By the way, my simple hypothesis to describe past and future warming is here.

As a final note, the last little dig on Steve McIntyre (the bit about FOIA requests) is really low.  First, it is amazing to me that, like Hogwarts students who can’t say the word Voldemort, the GISS folks just can’t bring themselves to mention his name.  Second, Steve has indeed filed a number of FOIA requests on Michael Mann, the GISS, and others.  Each time he has a pretty good paper trail of folks denying him data (Here is the most recent for the Santer data). Almost every time, the data he is denied is taxpayer funded research, often by public employees, or is data that the publication rules of a particular journal require to be made public.  And remember the source for this — this is coming from the GISS, which resisted McIntyre’s calls for years to release their code  (publicly funded code of a government organization programmed by government employees to produce an official US statistic) for the GISS grid cell rollup of the station data, releasing the code only last year after McIntyre demonstrated an error in the code based on inspection of the inputs and outputs.

At the end of the day, Hansen and Schmidt are public employees who like having access to government budgets and the instant credibility the NASA letterhead provides them, but don’t like the public scrutiny that goes with it.  Suck it up guys.  And as to your quest to rid yourself of these skeptic gadflies, I will quote your condescending words back to you:  Good Luck.  You’ll need it.

  • Jennifer

    CO2 in Hansen’s 1988 Scenario A might be quite similar to subsequent observations, but CO2 is not the only greenhouse gas. Real world forcings have not been nearly as high as those predicted by scenario A. You don’t even mention Scenarios B and C, and I find that highly dishonest.

    You go on to say the following:
    * the inherent impossibility of modeling such a chaotic system

    There is nothing impossible about modelling a chaotic system. But the way the climate system responds to external forcings is not chaotic.

    *scientists assume CO2 drives temperatures, so the models they build unsurprisingly result in CO2 driving temperature

    Scientists don’t assume this. They know this. They have known this for 100 years. CO2 is a strong absorber in the infrared, and it accounts for 10-25% of the total greenhouse effect. Did you not know this?

    *modelers assume WAY too much positive feedback. No reasonable person, if they step back from it, should really be able to assume so much positive feedback in a long-term stable system

    Again, they don’t assume positive feedback. Positive feedback is required to match the observations. The climate system is not ‘long-term stable’ – in fact, instability, in the form of sudden state changes, is the defining characteristic of the long term climate record.

    *When projected backwards, modeler’s assumptions imply far more warming than we have experienced, and it takes heroic assumptions and tweaks and plugs to make the models back-cast reasonably well.

    That’s simply untrue.

    *Its insane to ignore changes in solar output, and/or to assume that the sun over the last 40 years has been in a declining cycle

    No-one ignores changes in solar output, and no-one ‘assumes’ anything about the Sun’s behaviour over the last 40 years. Solar output has been intensively studied and measured. Study after study after study has found that solar changes cannot account for the present global warming.

    *Many models, by their own admission, omit critical natural cycles like ENSO/PDO.

    and many models don’t.

    Your simple hypothesis falls at the first hurdle, because it doesn’t explain why the stratosphere is cooling. Oceanic oscillations cannot possibly cool the stratosphere, and increases in solar output would warm it.

  • Raven

    The stratosphere is NOT cooling as expected: http://ams.confex.com/ams/15isa14m/techprogram/paper_125889.htm

    I am surprised this does not more discussion.

  • hunter

    Jennifer, Jennifer, Jennifer:
    Hansen is on record many times and many places asserting CO2 is *THE* driver of climate change.
    Rewriting history is fun, and helps keep faith alive, but it is not intellectually sustainable if honesty is the goal.

  • hunter

    Raven,
    AGW is a conclusion, not a science.
    Of course the prmoters are going to suppress pesky evidence that fails to support the prophecy.
    As we see here, it is annoying for the promoters to have people actually test their AGW models with data. Faith, not data, is required to properly understand the glory of AGW.

  • Jennifer

    Raven – I’ve got no idea why you think that paper says that the stratosphere “is NOT cooling as expected”. That’s not what it says.

    hunter – strange, then, that Hansen’s own 1988 paper included the effect of other trace gases. I think you’ve either misunderstood what Hansen has said, or just made up something you think he might have said. Could you maybe give a link to any of these statements you think exist?

  • hunter

    Jennifer,
    Try this:
    http://dotearth.blogs.nytimes.com/2008/03/19/back-to-1988-on-co2-says-nasas-hansen/
    Or this:
    http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/
    How about:
    http://www.etalkinghead.com/archives/how-much-co2-can-we-live-with-2008-10-10.html
    Or to quote a sworn statement by Hansen:
    “The average lag is
    a few hundred years, the time required for CO2, which is the dominant
    GHG feedback, to be flushed from surface reservoirs, mainly from the
    ocean4.” – page 8
    (see: http://www.greenpeace.org.uk/files/pdfs/climate/hansen.pdf )
    What I find interesting is that AGW is a belief ssytem that not only cannot be falsified, but its beleivers cannot deal with the statements of its promoters.
    I never said Hansen did not say there were no other GHGs in the Hansen apocalypse. I simply stated what Hansen and his acolytes and fellow promoters endlessly repeat.
    yet becuase my faith is not quite right, what I quote must be re-parsed.

  • An Inquirer

    Raven,
    Your link says that stratopheric measurements show “cooling of ~0.5 K over much of the globe for 1979-2005.”
    So do not understand your comment: “The stratosphere is NOT cooling as expected.” I will grant you this: the stratosphere has not cooled in the last 15 years — with maybe even a tiny upward linear trend. Also, stratospheric temperature trends do not match the monotonic increases in CO2 — rather they have step functions around major volcanic eruptions.
    (However, if I read the UAH website correctly, temperatures at 31 km will be down this year. Of course, one year does not make a trend!)

  • Jennifer

    hunter. First you say “Hansen is on record many times and many places asserting CO2 is *THE* driver of climate change”. Then you say “I never said Hansen did not say there were no other GHGs”. Can you see the problem?

    An Inquirer: “the stratosphere has not cooled in the last 15 years” – not according to UAH. Their measurements show a trend of (-0.56+-0.31) K/decade over the last 15 years. And not according to RSS either. Their data gives a trend of (-0.44+-0.32) K/decade. Which data were you using?

    It is not physically plausible that a volcanic eruption would cool the stratosphere without it warming again afterwards, and your idea about step functions is not statistically evident in the data.

  • hunter

    Jennifer,
    No, I think your problem is in trying to defend your prophet.
    And why quote me, when I provide you with quotes by Hansen? It is almost as if you can’t deal with the problems of your guy.
    But to your reading skills:
    Note that after I wrote *THE*, I did not write the word “only”. I was clearly stating to reasonable people an accurate representation of AGW orthodoxy, that CO2 is the meain driver of climate change.
    What would be a more interesting conversation is for you to defend the ridiculous assertion your guy makes about CO2. Clearly CO2 is not the main GHG, except in AGW chialism. Do you know what the main GHG driver is?

  • An Inquirer

    Jennifer,
    Did you start your 15 years in 1993 or in 1994? That could be the difference since the anomaly for 1993 was probably one degree higher than in 1994. (I was including end points in my approximation of 15 years, and likely I should not have.) My statement on the stratosphere comes from various graphs — here is one that uses RSS, UAH and HadAT:

    http://www.metoffice.gov.uk/research/hadleycentre/obsdata/HadAT.html

    From 1994 to present, there have been year by year wiggles, but quite flat overall with even a small increase using a linear trend.

    Again, we do not see a monotonic decrease in stratospheric temperatures, but rather dramatic shifts up with major volcanoes of El Chichón (1982) and Mt Pinatubo (1991), but these upward shifts were followed by drops that exceeded the increase. The last 28 years or so looks more like a step function rather than a dominating linear trend.
    I am not saying that “a volcanic eruption would cool the stratosphere without it warming again afterwards.” In fact, the data suggest that a major volcanic eruption warms the stratosphere followed by a cooling. In recent history, that cooling has been more than the warming. I am not aware of any explanation for that, and the observation could be coincidental of other factors.

  • Jennifer

    hunter: when you work out what point you’re trying to make, tell us. At the moment, I don’t have any idea what you are trying to say. When you write *THE* with capital letters AND asterisks, you make ‘only’ rather implicit. If that is not what you intended, please clarify.

    An Inquirer: I calculated trends starting in mid-1993, excluding the first few months when stratospheric temperatures were still clearly elevated by Pinatubo. The graph you quote shows that all three measures plotted on it give a clear downward trend since 1978. I see no evidence that the trend since 1993 is any different. What data are you fitting, exactly, that gives a ‘small increase’?

    As for the ‘step functions’, I got my words the wrong way around. To believe that there is some kind of step function, you have to believe that the warming caused by volcanoes is smaller than the subsequent cooling. Why would this be? There is no physical reason, and it’s not plausible. If it worked like that, the stratosphere would have cooled to absolute zero aeons ago. Exclude the volcanoes from the record, and a linear fit giving a downward trend looks perfectly consistent with the data.

  • Interesting how ‘Jennifer’ after demanding links, and being given four to examine, is now reduced to arguing over the various subtle shades of meaning of the word “THE”.

  • hunter

    Will,
    That is the typical response of the AGW true beleiver: ignore the data that is disagreeable and attack the messenger.
    When I post the cryosphere sat pics showing that Arctic ice today is nearly what it was in 1979 on the same date, I get ignored.
    When Jennifer demands I show where Hansen said CO2 is *THE* main GHG forcing, and I do, she quiccles over my stylistic choice of using *THE*.
    But hey, if I had glommed onto a faith-based psuedo science and was defending it against all data, I would avoid dealing with uncomfortable data as well.

  • I find the best response to stubborn indifference is PARODY…here’s one example…

    http://littleskepticpress.blogspot.com/

  • Jennifer

    Will Nitschke – are you here to discuss science, or to make childish snipes?

    hunter – how very interesting. Up there, you were screaming “*THE* driver of climate change”. Now, you are screaming “*THE* main GHG forcing”. The insertion of the word ‘main’ makes quite a difference to what you’re saying, but it’s still not clear what point you are trying to make. What do you think Hansen believes, and if you think he is wrong, then why?

  • cfdman

    Excellent article.

    Good example of lack of accountability while preaching religion…by a government employee.

  • John Anderson

    Excellent post. Keep up the good work.

  • Good work and well said.

  • ambiguous

    Jennifer:

    Sorry, I am perhaps too stupid to understand. Can you explain it plain words, please?

    AFAIK, Hansen graph expected lower rise of CO2 than really happened, yet the real world temperature does not seem to follow the prediction.

    What is “THE driver” then? Something else than CO2 contributes too and it did not happened?

    Or was CO2 causing the expected effect but something else mitigated it?

    I am not trying to attack AGW, just to understand. But I see no other options.

  • Jennifer

    ambiguous: trying to pin everything on one molecule, to be described as “THE” driver, is pointless. Of the molecules with long residence times that affect the radiation balance of the atmosphere, CO2 has the largest overall effect, but obviously you can’t just ignore all the others. Scenario A of the 1988 paper by James Hansen assumed that all greenhouse gases would continue to rise sharply. But just one year later, the Montreal Protocol rendered that assumption invalid. So, a comparison between Scenario A and observed temperatures is not meaningful. This paper may be of interest: http://www.nature.com/news/2008/050908/full/news.2008.1081.html

  • Hunter,

    “That is the typical response of the AGW true believer”

    Yes there are idiots on both sides of the debate, unfortunately. Warmists are quick to point to sceptics who argue illogically and visa versa. One has to wade through a lot of dross to find the odd insightful comment.

  • Ambiguous,

    “What is “THE driver” then? Something else than CO2 contributes too and it did not happened?”

    This is the ‘get out of jail free card’ inherent to the climate sciences. A scenario can never match reality, so there is always the excuse that comparing the prediction to reality is unfair. Following this line of argument a climate model is unfalsifiable. As CO2 levels are nonetheless comparable to scenario A (which ‘Jennifer’ does not dispute), and given that reality is diverging significantly from the prediction, one can apparently assume that the Montreal Protocol solved the climate problem, and we need not worry further about CO2 unless other GHG’s are added to the atmosphere again. I think this is the point that ‘Jennifer’ has made.

    Granted it cannot be argued that Hansen was ‘wrong’ in the narrow sense that ‘Jennifer’ defined. But it still demonstrates that CO2 by itself cannot cause the type of warming we should be worried about. I would also add that disproving Hansen’s work does not disprove AGW. He is only one scientist after all, and he’s made some fairly ‘out there’ claims anyway that are in serious disagreement with just about everyone including the IPCC. Even if CO2 does not cause warming there are other concerns, such as the effects of rapid ocean acidification on the marine biosphere.

  • Raven

    Jennifer,

    Did you actually look at the presentation? If you did you would see that the trend in stratospheric temperatures has been flat or rising since 1995 and all of the long term decline occurred prior to the pinatobu eruption. The presenter does take the usual alarmist position that if the data does not match the models then the data must be wrong but that does not change the fact that the DATA does not show significant cooling since 1995.

  • Jennifer

    The DATA, you shout, Raven. Did you actually look at the DATA? Scroll up a bit and you’ll see that I had a little look at the DATA. The DATA does show a significant cooling, from mid-1993 to the present, and I very much doubt that the story the DATA is telling us won’t change if the first 18 months of that was omitted. Perhaps you can derive your own trends, with error bars, from the DATA, and tell us what you think it says.

  • Chris Schoneveld

    Jennifer,
    If residence time of CO2 is supposedly long why then does the CO2 concentration in the atmosphere reacts almost instantaneously with seasons (the seasonal cycle is apparent on the CO2 graph from Mauna Loa: http://www.esrl.noaa.gov/gmd/ccgg/trends/ ) .

  • sabril

    I must admit that I enjoy watching the likes of Gavin Schmidt get increasingly defensive, flustered, and downright desperate as reality continues to encroach on their tightly circled wagons.

  • Jennifer

    Chris Schoneveld: the residence time has nothing to do with the seasonal cycle. Looks like you’d probably benefit from reading an atmospheric physics text book, because this is really basic stuff. Something for you to think about is this: if the residence time of CO2 is very short, as you seem to believe, then why have concentrations been steadily rising ever since the 1700s?

  • ambiguos

    Jennifer:

    “But just one year later, the Montreal Protocol rendered that assumption invalid.”

    Ok, so if I understand you right, ~ 10% drop in CFC reduced the “driving” impact of CO2?

    Sorry, this does not sound very plausible to me after 5 minutes investigation. wiki says that CFC replacements (HCFC) are as powerful greenhouse gases as CFC.

    Anything I am missing?

    “Scenario A of the 1988 paper by James Hansen assumed that all greenhouse gases would continue to rise sharply.”

    Is not that exactly what happend, except CFC being replaced by as powerful GHG HCFC?

  • Industry Insider

    “Jennifer,” I am glad you have returned. Things were getting boring around here without you.

  • Jerry D

    Everybody needs to step back and collect themselves. This reminds me of my sailing days when 2 boats would so fixate on one and other that they took themselves out of the race.
    When you look at this all I can conclude is we have a long way to go to understand the temperature of the earthand let alone if it is changing, in what direction and what causes it. When you consider the scope of the actions proposed to address this because our leadership thinks it is settled science it bogles the mind. How do we get the leadership to understand the science is still unsettled? You don’t do it by arguing the temperature in Siberia one month to the next!!!

  • Jennifer

    Ambiguos:

    “Ok, so if I understand you right, ~ 10% drop in CFC reduced the “driving” impact of CO2?”

    No. The concentration of CFCs does not change the forcing due to CO2. A drop in CFCs only changes the forcing due to CFCs.

    “wiki says that CFC replacements (HCFC) are as powerful greenhouse gases as CFC.”

    Wikipedia is often inaccurate. Stick to peer-reviewed journal papers, or text books.

    “Scenario A of the 1988 paper by James Hansen assumed that all greenhouse gases would continue to rise sharply.” Is not that exactly what happend, except CFC being replaced by as powerful GHG HCFC?

    No. What are you basing your claims on? You seem to be plucking suppositions out of the air.

    Industry Insider: I have no idea who you are.

  • hunter

    Jennifer,
    I keep quoting Hansen, and you keep hiding out by pretending you cannot understand my writing.
    Hansen is the source of your confusion, not me.
    Get him to explain it.
    You are being obtuse in a way that suggest more of trollishness than an actual attempt to communicate.
    Chris,
    Your point is incredibly good. Why is CO2 fluctuating so seasonally, and not simply aggregating?
    The AGW profits of doom have done a great job.

  • Industry Insider

    “Jennifer,” your identity is clear enough for those of us who have followed these discussions for a long time. I am sincerely glad you have returned, and I will continue to be civil/friendly toward you as I have always been.

  • An Inquirer

    Regarding Hansen 1988, I need to lean a little more toward Jennifer’s current position than what the skeptics are saying on this blog. There are other GHGs which heavily influenced the outcome of Hansons 1988 forecast. We have covered these issues repeatedly on this blog, so I will not repeat them all. But here are a few highlights:
    1. Hansen did himself no favor or credibility by inserting written statements that seem to contradict what he actually did.
    2. By labeling Scenario A the Business as Usual scenario and by carrying that Scenario far into the future, Hansen created a situation where readers can easily get the impression that Scenario A is one that deserves focus.
    3. There are other GHGs in Hanson’s model that make it legitimate to claim that overall inputs do not match Scenario A, but something lower.
    4. Hanson’s testimony to Congress occurred a year after the Montreal Protocol, so questions could be raised whether a business-as-usual scenario should have reflected that Protocol. However, Hanson certainly was working on his model before the Protocol; yet the outcome of the Protocol was quite well known ahead of time. Therefore, different views on this issues are certainly understandable.
    5. Given actual developments of inputs, I do not see how you can get below Scenario B.
    6. At least one AGW pessimist has said that Hanson 1988 model is no longer relevant (indeed, apparently it can no longer be compiled and run) because models have improved in the last 20 years. Of course, that begs the question whether we should rely on today’s models or models that will be developed 20 years from now.

  • An Inquirer

    Jennifer,
    Well, it appears that we are looking at the same graph, but we are having different reference points. We have this understanding in common, stratospheric temperatures are now generally lower than they were in 1978. You seem to say that it has been a consistent trend. When I look at the graph, I see it being flat since 1994. Yes, there is a big difference whether you add 18 months on the beginning — because stratospheric temperatures were much higher 18 months earlier, perhaps due to volcanic activity. I see an anomaly of around -0.5 for the three measures in 1994, and now they are around -0.2 in the Hadley site. I am not offering any scientific explanation why stratopheric temperatures dropped by more than they rise following the last two or three volcanoes. I am just pointing out that is what the graph shows. We have not had a major volcano the last 1.5 (or so) decades and stratospheric temperatures have been flat to slightly positive. (And yes, you have a valid point that stratopheric temperatures cannot have consistently fallen by more than volcanic-induced increases throughout history without some positive trends in between.)

  • Jennifer

    An Inquirer: rather than just eyeballing, can you tell me what trend you derive from the data? Because from 1994-present, I calculate a trend of -0.032 K/decade from UAH and -0.028K/decade from RSS. I cannot see how you could even describe the trend as flat, let alone slightly positive.

    It seems clear to me that the reason the drop after the volcanic eruptions is greater than the preceding rise is simply that the volcanic effect is superimposed on a downward linear trend. I see no statistical justification for describing the stratospheric temperature trend as a step function, and there is no possible physical mechanism that could produce one, that I can think of. Do you think otherwise?

  • An Inquirer

    Jennifer: I am sure that it is an innocent oversight. I have given you a website that is typical of data sources I use; you have not given me your source — and typically you readily provide websites. It would be convenient if I could post those stratospheric temperature graphs in the comment section (Maybe Warren Meyer could post them?) because they quite clearly show wiggles since 1994 but no downward trend.

  • Jennifer

    What you haven’t yet told me is the trends that you’ve calculated, for 1994-present. The data sets from which I got the numbers I quoted are:

    RSS: http://www.remss.com/data/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TLS_Anomalies_Land_and_Ocean_v03_2.txt
    UAH: http://vortex.nsstc.uah.edu/data/msu/t4/uahncdc.ls

  • Jennifer –
    I don’t see where anyone is saying it is impossible to model a chaotic system. However, by definition chaotic systems are extremely sensitive to initial conditions – model inputs in this case. The point is that the “data” produced by the model will vary wildly depending on the inputs. The models are doomed to fail. I think the comparisons of model output to real data is proving that point. The models are worse than useless.

  • Ah, Gavin Schmidt, Dr. Hansens own little water carrier. Word of caution… whenever you read or even argue with Gavin keep in mind the following: He is an expert in what I like to call “baffle them with bull shit” and he uses it quite frequently.

  • Bart

    Jennifer said: “Again, they don’t assume positive feedback. Positive feedback is required to match the observations.”

    That is to say, it is the only thing the researchers could think of that allowed them to match the observations. This is an argument from ignorance, a classic logical fallacy.

    “The climate system is not ‘long-term stable’ – in fact, instability, in the form of sudden state changes, is the defining characteristic of the long term climate record.”

    Sudden changes can occur from internal instability, or from external forcing. This is petitio principii or begging the question, another classic logical fallacy.

  • barry

    Warren wrote: “Since when has direct comparison of forecast models against observation and measurement been the wrong way to validate or invalidate the forecast or model?”

    Since never. But this is a completely false interpretation of Schmidt’s statement.

    “Instead, the anti-model crowd focuses on the minor issues that crop up every now and again in real-time data processing hoping that, by proxy, they’ll find a problem with the models.”

    The “minor issues that crop up every now and again in real-time data processing” are not robust “observation and measurement”, obviously.