Trends, change points & hypotheses

by Judith Curry

Jonathan Leake asks in the Sunday Times: “Why has it warmed so much less than the IPCC predicted?

The article provides a good overview on the debate.  Some summary excerpts:

Is it really true that global temperatures have not risen since 1997?

The simple answer is: they have risen, but not by very much. “Our records for the past 15 years suggest the world has warmed by about 0.051C over that period,” said the Met Office. In layman’s terms that is 51 thousandths of a degree.

One [dataset], held at the National Climate Data Centre (NCDC), run by America’s National Oceanic and Atmospheric Administration, suggests that global temperatures rose by an average of 0.074C since 1997. That’s small, too — but it is another rise.

A third and very different data set is overseen by John Christy. . . “From 1997-2011 our data show a global temperature rise of 0.15C,” he said. 

Overall, then, the world has got slightly warmer since 1997. Perhaps the real question is: why has it warmed so much less than was predicted by the climate models?  

For the critics of climate science this is a crucial point — but why? The answer goes back to the 2001 and 2007 science reports from the Intergovernmental Panel on Climate Change that had predicted the world was likely to warm by an average of about 0.2C a decade. The implication was that temperatures would rise steadily, not with 15-year gaps. The existence of such gaps, the critics argue, implies the climate models themselves are too flawed to be relied on.

Some scientists appear to be warning we will fry, while other sources fear we will freeze.

How we interpret the 20th century temperature data has implications for how we project future temperature variability and change.

Climate trend statistics and graphs

So, how should we analyze the recent time series of temperature global or local temperature?   Various blog posts have attempted to instruct us on this matter:

Josh encapsulates all this with a cartoon.

An argument for change-point analysis and analysis of partial time series is provided by Raymond Sneyers:  Climate Chaotic Instability: Statistical Determination and Theoretical Background [sneyers environometrics].

Abstract.  The paper concerns the determination of statistical climate properties, a problem especially important for climate prediction validation. After a brief review of the times series analyses applied on secular series of observations, an appropriate method is described for characterizing these properties which finally reduces itself to the search for existing change-points. The examples of the Jones North Hemispheric land temperature averages (1856±1995) and of the Prague Klementinum ones (1771±1993) are given and results discussed. Relating the observed chaotic character of the climatological series to the non-linearity of the equations ruling the weather and thus climate evolution, and presenting the example of a solution of the Lorenz non-linear equations showing that non-linearity may be responsible for the instability of the generated process, it seems justified to conclude that there are severe limits to climate predictability at all scales.

Three competing hypotheses  

Consider the following three hypotheses that explain 20th century climate variability and change, with implied future projections:

I.  IPCC AGW hypothesis:  20th century climate variability/change is explained by external forcing, with natural internal variability providing high frequency ‘noise’.  In the latter half of the 20th century, this external forcing has been dominated by anthropogenic gases and aerosols.   The implications for temperature change in the 21st century is 0.2C per decade until 2050. Challenges:  convincing explanations of the warming 1910-1940, explaining the flat trend between mid 1940’s and mid 1970’s, explaining the flat trend for the past 15 years.

II. Multi-decadal oscillations plus trend hypothesis:  20th century climate variability/change is explained by the large multidecadal oscillations (e.g NAO, PDO, AMO) with a superimposed trend of external forcing (AGW warming).  The implications for temperature change in the 21st century is relatively constant temperatures for the next several decades, or possible cooling associated with solar.  Challenges: separating forced from unforced changes in the observed time series, lack of predictability of the multidecadal oscillations.

III:  Climate shifts hypothesis: 20th century climate variability/change is explained by synchronized chaos arising from nonlinear oscillations of the coupled ocean/atmosphere system plus external forcing   (e.g. Tsonis, Douglass).  The most recent shift occurred 2001/2002, characterized by flattening temperatures and more frequent LaNina’s.  The implications for the next several decades are that the current trend will continue until the next climate shift, at some unknown point in the future.  External forcing (AGW, solar)  will have more or less impact on trends depending on the regime, but how external forcing materializes in terms of surface temperature in the context of spatiotemporal chaos is not known. Note:  hypothesis III is consistent with Sneyers’ arguments re change-point analysis.   Challenges:  figuring out the timing (and characteristics) of the next climate shift.

There are other hypotheses, but these three seem to cover most of the territory.  The three hypotheses are not independent, but emphasize to varying degrees natural internal variability vs external forcing,  and an interpretation of natural variability that is oscillatory versus phase locked shifts.   Hypothesis I derives from the 1D  energy balance, thermodynamic view of the climate system, whereas Hypothesis III  derives from a nonlinear dynamical system  characterized by spatiotemporal chaos.  Hypothesis II derives from climate diagnostics and data analysis.

Each of these three hypotheses provides a different interpretation of the 20th century attribution and has different implications for 21st century climate.   Hypothesis III is the hypothesis that I find most convincing, from a theoretical perspective and in terms of explaining historical observations, although this kind of perspective of the climate system is in its infancy.

Cherry picking data, or testing alternative hypotheses?

Back to the issue of cherry picking data, and interpreting the temperature time series for the past two decades.

Is the first decade+ of the 21st century the warmest in the past 100 years (as per Peter Gleick’s argument)?  Yes, but the very small positive trend is not consistent with the expectation of 0.2C/decade provided by the IPCC AR4.  In terms of anticipating temperature change in the coming decades, the AGW dominated prediction of 0.2C/decade does not seem like a good bet, particularly with the prospect of reduced solar radiation.

Has there been any warming since 1997 (Jonathan Leake’s question)?  There has been slight warming during the past 15 years.  Is it “cherry picking” to start a trend analysis at 1998?  No, not if you are looking for a long period of time where there is little or no warming, in efforts to refute Hypothesis I.

In terms of projecting what might happen in coming decades, Hypothesis III is the best bet IMO, although it is difficult to know when the next change point might occur.  Hypothesis III implies using 2002 as the starting point for analysis of the recent trend.

And finally, looking at global average temperatures makes sense in context of Hypothesis I, but isn’t very useful in terms of Hypothesis III.

And none of this data analysis is very satisfying or definitive owing to deficiencies in the data sets, particularly over the ocean.

IMO, the standard 1D energy balance model of the Earth’s climate system will provide little in the way of further insights; rather we need to bring additional physics and theory (e.g. entropy and the 2nd law) into the simple models, and explore the complexity of coupled nonlinear climate system characterized by spatiotemporal chaos.

1,022 responses to “Trends, change points & hypotheses

  1. Very good post. Sensible. Thanks.

    • Above, in this comment, Judith asks me:

      I don’t see how this statement by Leake is misleading:

      “For the critics of climate science this is a crucial point — but why? The answer goes back to the 2001 and 2007 science reports from the Intergovernmental Panel on Climate Change that had predicted the world was likely to warm by an average of about 0.2C a decade. The implication was that temperatures would rise steadily, not with 15-year gaps. The existence of such gaps, the critics argue, implies the climate models themselves are too flawed to be relied on.”

      Previously I focused on what is misleading about the headline.

      Now Judith asks me about an extract. What’s misleading is the big I have put in bold. As we’ve seen already, even in AR1 the predictions cited above conclude with the explicit statement:

      The rise will not be steady because of other factors.

      Leake’s articles in climate are nearly always highly misleading. Your extract is no exception. Leake explicitly suggests the IPCC proposed temperatures would rise steadily. The IPCC, on the other hand, explicitly says the opposite.

      It bothers me, frankly, that you don’t acknowledge how misleading Leake is in his presentation. Decadal scale variation is an important question worth looking at; and Leake makes a total hash of it.

      • Chris, the IPCC said 0.2C/per decade for two decades. Then there is 15 years without warming. 15 years out of 20. What is the problem here?

      • The problem is that Leake said the rise would be steady, and the IPCC said it would NOT be steady.

      • Having explicitly told you want was misleading in the extract you provided from Leake, let’s go on to what is misleading in your own comments, Judith.

        You say:

        Chris, the IPCC said 0.2C/per decade for two decades. Then there is 15 years without warming.

        First, citation please. Where is this prediction for two decades? Do you mean the 1992 supplement cited earlier in this thread with a prediction to 2025? That’s more than 30 years. Or something else? WHICH report?

        Second. What’s this “without warming”? Even Leake doesn’t make that mistake. The issue is 15 years with a small trend, not with no warming at all.

      • Chris, this is my last response to you. As I cited earlier

        http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html

        For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. {10.3, 10.7}

      • Yes, this is simply wrong.

        Judith you do yourself no credit by going along with this nonsense.

      • Markus Fitzhenry.

        “Michael | February 7, 2012 at 10:43 pm |
        Yes, this is simply wrong.
        Judith you do yourself no credit by going along with this nonsense.”

        Michael really means, you do yourself no credit because you’re not on our side anymore.

      • I haven’t reviewed all the AR4 statements, but I tend to agree with Anteros that the issue isn’t enormously important, although I think Chris Ho-Stuart is technically correct. Interdecadal variability is a well recognized climate reality. If a 0.2C/decade average out to 2050 was predicted, that wouldn’t preclude a lack of warming in some particular decade. For the separate AR4 2007 claim of 0/2C/decade for “the next two decades”, am I wrong in interpreting that to mean the interval from 2007 to 2027? Clearly, we haven’t proceeded far enough into that interval to judge that prediction.

      • Chris, this is my last response to you. As I cited earlier

        Judith, that would be very disappointing. I aim to be robust, but fair; and I’d really like to help you get a better support for the discussions here. (SkyDragon; sorry I have been slow on that!)

        I’d like you to reconsider the above please… but I won’t refrain from challenging what I think is misleading or wrong. I would hope that isn’t the problem! Take me seriously, please.

        For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. {10.3, 10.7}

        Good! That’s a citation we can use, going to AR4, published in 2007.

        Problem is… that ISN’T going to help with the slow down over the last 15 years. You said earlier:

        Chris, the IPCC said 0.2C/per decade for two decades. Then there is 15 years without warming. 15 years out of 20. What is the problem here?

        But AR4 was published in 2007! So no, there HASN’T been 15 years “without warming” (or with reduced warming) since the prediction you are citing.

        Don’t just run away from that. Talk to me. I won’t pull punches where I think you are wrong, but I’m not going to just dismiss or insult you.

        I said in another comment that I expect the recent lull to change and warming to accelerate somewhat. That’s not just my prediction. That’s based in part on an expected change in conditions that impacted the earlier 15 years. TSI is likely to go up. ENSO is likely to start warming things up a bit faster. If this doesn’t happen, then I’ll seriously have to review my position.

        It’s really confusing following this when there are different reports being cited all over the place. When you spoke of predictions bearing upon the 15 years just past, I was pretty sure you must have been referring to reports from before that lull.

        The standard conclusion, as I have always understood it, is that warming is not steady, and that lulls over a decade or more are common. I expect — in line with the AR4 extract you are citing — that the recent lull is going to show up as a lull, with stronger warming before and after. A rise of 0.2 C/decade (or better, of between 0.15 and 0.3) over the next two decades (from 2007, if you like!) sounds pretty sensible to me.

        Summary.
        (1) Leake’s initial question is misleading. IPCC predictions recognize the existence of changes in the pace of warming over those time scales.
        (2) Leake’s claim of IPCC meaning “steady rise” is flatly contradicted by the actual IPCC report.
        (3) The expectation in AR4 (2007) of warming over the coming two decades is not falsified by slower warming over the period before it was published.

        Cheers — Chris

      • Chris, I think part of the problem is that the AR4 used the same scenario chart as the TAR.
        http://i122.photobucket.com/albums/o252/captdallas2/ipccscenarioschartsmilie.png

        The smilie is off a couple years, but it sure looks like about 0.4 by 2020. I think this boils down to the IPCC not updating their documents.

      • Chris:

        “Good! That’s a citation we can use, going to AR4, published in 2007.

        Problem is… that ISN’T going to help with the slow down over the last 15 years. You said earlier:

        Chris, the IPCC said 0.2C/per decade for two decades. Then there is 15 years without warming. 15 years out of 20. What is the problem here?

        But AR4 was published in 2007! So no, there HASN’T been 15 years “without warming” (or with reduced warming) since the prediction you are citing.”

        The projection of .2C per decade is based on the scenarios.
        The scenarios used projected forcing from at least the year 2001 going forward. The SRES were published in Nov of 2000.

        So, if we want to compare the projection of .2C to observations, 2001 is probably the most defensible starting point. Since 2001 the observations
        fall outside a 95% confidence interval for a .2C projection. That can happen for a variety of reasons.

        1. Some of the models run too hot. For example, the mean estimate for sensitivity is 3C. more than half of the models have sensitivity higher than this.

        2. Emissions did not track with A1B projections or other forcings did
        not track with projections.

        3. rare events happen, and in shorter time scales they are more likely
        to occur

        Finally, there is no hard and fast minimum number of years required to reject the projection.
        There is simply a probability that one can calculate. For example,
        If observations ran 10C cooler after 5 years or 10C warmer after 5 years we would be right to conclude that something was amiss with the models.

        The problem is that there hasnt been enough attention paid to WHY the models are not tracking observations more accurately. For example,
        the new NCAR model looks to be even more out of wack with observations.

        A review of Ar4 projections indicates that there is a case to be made for models running too hot. That possibility, hasnt been addressed or investigated or eliminated as a possibility. preliminary Ar5 results are still running too hot in TLT as Santer recently showed at AGU 2011.

      • Latimer Alder

        @chris ho-stuart

        Stop digging, matey. You’re in a big enough hole already without shouting and screaming to bring more attention to it.

      • steven mosher

        Fred:

        “For the separate AR4 2007 claim of 0/2C/decade for “the next two decades”, am I wrong in interpreting that to mean the interval from 2007 to 2027? Clearly, we haven’t proceeded far enough into that interval to judge that prediction.”

        The closest thing to a near term prediction is

        http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-3-1.html

        That means we can wait until 2030 to see if the models run in the year
        2000 were correct. Until then, why trust them.

        The other point is the model results published in 2007, actually start in 2001, so thats the data you want to start your test.

        All that said. If 2012, turns out to be 10C cooler than 2001, what would
        you conclude about the models? would you say that its too early to render a judgement? 5 C cooler? 1C cooler?.

        The bottom line is
        this. The models were run with historical forcing up to 2000 and projected forcing after that. Second, differences in projected forcing dont change outputs until 20+ years down the line. the models clearly cant exhibit any behavior they want in those 0-20 years and still hit the projections
        that close 30 years out. At all times along the process ( 0-20 years) we can surely note whether the models are falling above or below the observations. And we can note that the longer the models run hotter than observations, the more rapid the warming will have to be to catch up and
        hit the window.

      • Chris:

        “But AR4 was published in 2007! So no, there HASN’T been 15 years “without warming” (or with reduced warming) since the prediction you are citing.”

        A) See Fig SPM.5 from the reference. Model projections start 2000.

        B) See Fig SPM.5 from the reference. The trends for all of the scenarios for the period 2000-2040 are effectively linear, similar to or lower than the trend 1997-2000 that informed the model start point, and on the scale of the predicted 0.2C increase there is no variability to speak of in any of them.

        The model projections cannot be reconciled with the last 15 years of flat temps, regardless of when you start.

        To achieve the predicted 0.4C rise, we would need to see about 25 years worth of 1990’s style warming in the next five years.

        Are you a betting man?

      • The believers cannot stand having the tenets of their faith challenged. Chris, as we see, likes to call those who point out problems in his faith, ‘liar’.
        For AGW believers to be so allegedly obsessed with communication, it is ironic how often they retreat to simply…denying….what other people say and declaring them untruthful.

      • Steve Mosher – Ordinarily I wouldn’t add to the excessive column space already devoted to this not very important point, but since you addressed your comment to me, I’ll respond.

        Chris Ho-Stuart is correct in criticizing Leake’s claim that the warming has been less than predicted. The various IPCC curves that have been cited are all drawn with the understanding that decade to decade variation from them is something to be expected – the curves are smooth simply because there’s no way of knowing which decades will vary from the projected mean and in which direction. Not to belabor the point, but predictions of 0.2/decade average out to mid century can’t be invalidated by data from the first decade of the century. Predictions of 0.2 per decade for a specified two decades (“the next two decades”) can be invalidated by data from 2007 to 2027, but not by anything that hasn’t gone beyond early 2012. The fact that projected curves were drawn starting in 2001 isn’t a test of “the next two decades”.

        You are right that if 2012 is 10 degrees colder than 2001, the models will be in trouble.; And so will the rest of us. The same will be true if it’s 10 degrees hotter.

        The most important point I wanted to make was in the first sentence. This is inconsequential stuff, as is obvious if one looks at the last 100 years rather than the last 10 to 15. Quibbling about it seems to me to be more about scoring points than understanding what is going on now, or will in the future. With that in mind, I’ll try to refrain from getting caught up in the arguing if these points continue to generate further comments, and to respond only if something new and important is added to the discussion.

      • Fred,

        “Chris Ho-Stuart is correct in criticizing Leake’s claim that the warming has been less than predicted. The various IPCC curves that have been cited are all drawn with the understanding that decade to decade variation from them is something to be expected – the curves are smooth simply because there’s no way of knowing which decades will vary from the projected mean and in which direction.”

        Honestly. It’s like watching someone try to play Twister. Here’s a graph:

        http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/decadal-prediction

        Look at the confidence levels. Did they mean those? Perhaps they meant to say “don’t forget to add in all the extra extra variability that we haven’t crowbarred into our models yet.”

      • Chris Ho Stuart: The problem is that Leake said the rise would be steady, and the IPCC said it would NOT be steady.

        Did IPCC language allow for the possibility that the rate of increase might possibly be way below the predicted rate for 50 to 100 years? I put it this way because of the vagueness in the phrase “would NOT be steady”. A large number of us interpreted the IPCC language as excluding the possibility of next to no warming for a period of 15 years. Had they seriously considered what has happened as a possibility, warnings of disaster would have been less shrill.

        Thus, I think that Leake and Curry have interpreted the IPCC language fairly.

        curryja: Chris, the IPCC said 0.2C/per decade for two decades. Then there is 15 years without warming. 15 years out of 20.

        Almost for sure, had the IPCC anticipated what we have as a real possibility, they’d have written differently. For example, they might have written, “there may be 15 – 30 years of no warming before the overall warming trend resumes, and 0.2C/decade is the anticipated mean rate over the century.” But they didn’t.

        Thus, I think that Leake and Curry have interpreted the IPCC language fairly.

      • P.S.

        Here’s the updated Met Office prediction graph:
        http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/long-range/decadal-fc

        Keep a copy in your files.

      • James Evans – The link and graph you refer to are interesting, and I think might help readers better appreciate Chris Ho-Stuart’s conclusion that predictions can’t yet be made accurately for individual decades, which is why Leake’s criticism of the IPCC model-based curves was misguided.

        The models you refer to are very different from those cited by the IPCC. They involve the DePreSys approach to decadal climate modeling, based on the premise that better decadal forecasts will be possible if more attention is devoted to model initialization. The latter is not a major focus of the GCMs cited by the IPCC because over multiple decades, their projections converge toward the same trajectory from different initial conditions.

        The graph you linked to shows that the DePreSys attempts may be a step in the right direction, but still have a long way to go. Notice for example, the great deviation in the hindcast due to the 1991 Pinatubo eruption, which obviously couldn’t be anticipated by better initializations.

        Basically, the point made by Chris is pretty universally understood within climate science. Average temperature anomalies can’t be expected to anticipate actual values for any single decade, and are intended to be interpreted over multiple decades. It does seem to me that a great deal of time is being wasted here arguing about that, and could be better spent on assessing the relationship between interval lengths and signal to noise ratios.

      • Fred –

        I agree with you.

        Isn’t it noticeable that this is an observation [that a decade is harder to predict/less meaningful than longer periods] that should be made equally by people wherever they are on the climate spectrum?

        Although it is tempting, I do find it tiresome that partisans jump on the tiniest ‘trend’ as containing large amounts of ‘meaning’. It could almost be used as a test of partisanship – anybody claiming [clearly] unjustified significance could be put in a sin-bin of ‘not to be taken seriously for a month’.

        That would thin out the debate a bit

      • the key issue here is the length of such pauses that is “allowable” by H1. The IPCC and its proponents are emphatic that the flat, cool trend from mid 1940’s to mid 1950’s is not natural variability, but anthropogenic aerosol forcing. So pauses of 10-15 years are now expected, but not pauses approaching 30 years?

      • So pauses of 10-15 years are now expected, but not pauses approaching 30 years?

        As I understand it, pauses of 30 years would be expected, albeit very rarely. Although it would certainly raise questions about the accuracy of models, the existence of such a period wouldn’t disprove AGW nor IPCC predictions of decadal averages; only those predictions that are explicit about specific 30 year time periods would be disproven.

        Why did you omit the following even though you spoke of predictions that were right next door?

        The rise will not be steady because of other factors.

      • “The IPCC and its proponents are emphatic that the flat, cool trend from mid 1940′s to mid 1950′s is not natural variability, but anthropogenic aerosol forcing.”

        Judy – I’m somewhat familiar with the IPCC reports (mostly AR4, less so for earlier ones), but I haven’t seen that claim. Could you cite the exact section and words where the IPCC emphatically attributes the temperature fluctuations between the mid 1940’s tand mid-1950s to anthropogenic aerosols while excluding natural variability? My own reading of the evidence is that much of the fluctuation during that interval was due to natural unforced variability from internal climate dynamics, with aerosols perhaps adding some cooling after 1950 but not necessarily a major player before 1950 nor necessarily an exclusive player from 1950 to the mid 1950s. If you could quote the exact IPCC assertion in this regard, it would be helpful.

      • there seems to be a hot-button issue with respect to whether it was implied by IPCC and scientists that there would be no more than a “few” years of pauses, slowdowns, coolings etc.

        i think we are conducting a proxy argument about spin that was spun in previous years and to which the original spinners, whoever they are, would now respin.

      • Fred M,

        I’ve just been reading back issues of Isaac Held’s blog and came across this gem:

        “The model results give a hint of mid-century flattening, which is typically attributed to an increase in cooling aerosols, although not as pronounced as in the GISS curve, nor exactly contemporaneous with it. Is this just part of the random variation inherent in the model runs, or can some of the flattening be attributed to changes in WMGGs?

        Reply
        Isaac Held says:
        March 29, 2011 at 9:19 am
        There is some flattening of the CO2 evolution prescribed here (between 1935-1945) which is based on Etheridge et al.”

        It adds another dimension and something I was unaware of before.

      • On gets the impression you are of the opinion that most of us lack reading skills and therefore you feel it is your duty to tell us what is being said.

      • BillC – Thanks for quoting my question to Isaac Held. The possible CO2 “flattening” was pre-1945 and therefore largely irrelevant to the abrupt post-1945 dip before the curve flattened out between about 1950 and 1976. The reason for a reduced CO2 rate of rise was probably not due to a reduction in emission rates, but it may have reflected carbon cycle feedbacks that slightly altered the balance between atmospheric CO2 and terrestrial and oceanic sinks. Of the sinks, ENSO phenomena appear to play a significant (but transient) role in altering terrestrial CO2 uptake, but I don’t know how well that correlates with those early observations. The early 1940s were characterized by strong El Ninos that probably contributed to the spike around 1945, and whose cessation contributed to the post-1945 decline, possibly in combination with PDO changes.

      • Fred Moolten: This is inconsequential stuff, as is obvious if one looks at the last 100 years rather than the last 10 to 15.

        You ignore two important facts. (1) The model forecasts were recently made, so is is the recent record that tests the forecasts. (2) The last 10 to 15 years have the highest CO2 concentrations.

      • MattsStat – Your point 1 hasn’t been ignored but has been addressed by Chris, me, and others. Please see our comments. Your point 2 hasn’t been ignored either, but doesn’t change the principle that predictions for individual decades aren’t useful at the current state of our ability to predict. The large scale interdecadal variability is apparent in the climate record of the past 100 years and is not a recent phenomenon.. That too is encompassed in our earlier comments.

      • When you read through this thread of comments it seems clear that some people have blind faith in the modelling approach used by the IPCC.

        This faith is in spite of all evidence that shows the approach of averaging the results of models demonstrates that they have no particular model that can be relied upon for accuracy and the fact that none of the models outputs match observations.

        What is the justification for such faith?

      • The problem here is the intentional ambiguity in the IPCC reports. They amass hundreds of pages of scientific research. They assume a basis for all this, the radiative heat absorption by CO2(this is in their founding documents), and produce massive summaries, generally including long term ordinary linear regression in approriately applied to a time series, and then make a statement such as “an increase of .2 deg C/decade”. Hidden away is the caveat “The rise will not be steady because of other factors.”

        Pardon me, but you can’t hammer away at an argument that CO2 is the cause of the temperature increase for page after page and then cover your ass with a few lines here and there that “the rise will not be steady”, or the effect of clouds is poorly understood. Statements like this deserve at least as much page space as the other arguments because they point out major weaknesses that are not fully assessed.

        In this context Leake’s statement “The implication was that temperatures would rise steadily, not with 15-year gaps. ” is a perfectly resonable takeaway. That was a major implication to my mind in almost every paper I’ve read that predicted global warming. In most cases the author’s seamlessly slid from solid conclusions into “this is not inconsistent with CO2 causing global warming” and some statement about rising temperatures. So don’t be too surprised when people pick up on the implied conclusions that are so forcefully expounded.

      • Fred Moolten: MattsStat – Your point 1 hasn’t been ignored but has been addressed by Chris, me, and others. Please see our comments. Your point 2 hasn’t been ignored either, but doesn’t change the principle that predictions for individual decades aren’t useful at the current state of our ability to predict. The large scale interdecadal variability is apparent in the climate record of the past 100 years and is not a recent phenomenon.. That too is encompassed in our earlier comments.

        Those points that you restate so clearly are the particular points why looking at the last 100 years instead of focusing on the last 15 would be a misdirection. We know already that interdecadal variability is great and that predictions for individual decades are not useful. However, the prediction (scenario, hypothesis, whatever) is tested by the data that came after it was made, and the data since the prediction have diverged from the prediction more than was expected by the people who made the prediction. It is possible for the 50 year prediction to be more accurate than the 15 year prediction, but until such a potentiality has been actually demonstrated to be true, every year that the data diverge from the prediction discredits the theory on which the prediction rested.

        Your points clearly express why the sentence that I quoted was a misdirection, i.e. a bad recommendation.

      • Fred,

        What a load of blah.

        “Notice for example, the great deviation in the hindcast due to the 1991 Pinatubo eruption, which obviously couldn’t be anticipated by better initializations.”

        I can’t see anything special about that dip in temperatures. There have been many similar dips in the global temp graph. (Just look at it.) That particular dip is asccociated with Mt Pinatubo, because it helped dig the models out of a hole at the time. Which huge volcanic eruptions caused the other dips?

    • Oops. Sorry, located the above comment badly. Sorry.

      • That’s OK. I was just what I was looking for, thank you. Ready…

        http://www.guardian.co.uk/environment/2012/feb/08/glaciers-mountains?intcmp=122

        more oops looks like.

      • Chief Hydrologist

        Is there anyone seriously trying to disprove simple radiative physics in the atmosphere? At least – no one who is taken seriously.

        So here is the 20th Century signal cleaned of the decadal signal – http://s1114.photobucket.com/albums/k538/Chief_Hydrologist/?action=view&current=MONOTONIC.gif – it is from a Tsonis et al paper.

        The residual warming in the 50 years to 2000 was about 0.08 degree C. The IPCC is wrong – the models are wrong – because they missed this mode of internal variability without which no sense can be made of any trend.

        The whole box and dice of global warming is totally kaput – it needs a fundamental rethink. The maximum rate of warming in the 20th century was 0.08 degrees C/decade from all other factors. Can we use the 20th century natural variability to predict 21st century natural variability? I don’t think so.

        Robert I Ellison
        Chief Hydrologist

      • The report of my illness grew out of his illness. The report of my death was an exaggeration.

        Mark Twain

        It appears the report of the Himalayan glaciers’ demise has been equally exaggerated out of all proportion.

        Recent contributions of glaciers and ice caps to sea level rise Thomas Jacob, John Wahr, W. Tad Pfeffer & Sean Swenson, Nature (2012) doi:10.1038/nature10847

        The [Glaciers and ice caps] (GICs) rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr−1 for 2003–2010, compared with 47–55 Gt yr−1 in previously published estimates2, 5.

        Contrast 2010: Settling the science on Himalayan glaciers
        Nature Reports Climate Change doi:10.1038/climate.2010.19

        Current estimates suggest there are about 12,000 to 15,000 (glaciers) in the Himalayas and about 5,000 in the Karakoram. Of these thousands of glaciers, only 15 have been measured on the ground to see if they are gaining or losing ice overall. Despite the scarcity of data, trends are emerging. “It is pretty clear that the Himalayan glaciers have been losing mass, with markedly greater loss in the past decade than earlier,”. . .

        That was only a 1000 fold extrapolation!

        That 2012 net loss measurement of Himalayas’ glaciers is only 8% of the previous scientific evaluations. That’s > 90% error, not 90% confidence! Contrast IPCC’s claim (based on gray literature):

        “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.”

        Whatever happened to IPCC as a review of the science?

        The uncertainties in the Himalayan glaciers appear to be greater than IPCC’s claimed confidence!

  2. It is simply not true that there is an “IPCC hypothesis” that is falsified by a short term (scale of a decade or so) variation that is somewhat above or below the general trend.

    Short term variations like this ARE a matter of scientific interest and hypothesis and competing ideas. They are not a matter of a clear consensus. And neither does the IPCC make strong claims or hypotheses on them — other than the statement that they ARE comparatively short term and that we expect the longer term trend to continue upwards.

    It is also a misrepresentation of what the IPCC does to speak of IPCC “hypotheses”. The IPCC is not a research body. They don’t do scientific work. They summarize it. They make statements with associated confidence levels, based on the combined work of a lot of scientists, but these are not in the form of a “hypothesis”, but a conclusion. Whether you agree with them or not, the distinction matters.

    • The post does not claim that the AGW hypothesis is falsified solely by the recent lack of warming. It merely points out two competing hypotheses. (The falsification involves other factors, in my view.) Calling it the IPCC hypothesis makes sense because their endorsement is the focus of the debate.

      • This post starts out by saying it has warmed less than the IPCC predicted. No prediction is cited. That is because it doesn’t exist.

      • IPCC AR4 prediction: 0.2C/decade during the first half of the 21st century. This prediction is cited in Leake’s article and also in my post.

      • Chris –

        If a particular prediction was required, the post could have used the prediction from the FAR that if there were few or no steps taken to limit greenhouse gases, temperatures would rise by 0.3 degrees per decade. This was predicted to mean a rise of 1 degree C by 2025.

        Of course, times have changed, but if we pretend those predictions were never made, how can we learn from them?

      • IPCC prediction: 0.2C/decade during the first half of the 21st century. This prediction is cited in Leake’s article and also in my post.

        What year is this? How many years in a century?

      • In the AR4, out to 2050

      • Judith, the prediction is not for a rise of 0.2 every decade. If you think there is a prediction, for heavens sake quote it.

        I don’t see anything which I would call a “citation” to any such prediction. A cite is more than just “the IPCC says”. You give some other cites, but not one for the alleged IPCC prediction. You AND Leake confuse the magnitude of the long term change expected with a prediction that applies to the last ten years.

        Anteros, you also. QUOTE or CITE your alleged prediction.

      • Judith –

        As an average rise per decade.

        It is legitimate to question, as the linked article does, whether:

        The implication was that temperatures would rise steadily, not with 15-year gaps.

        And if so, what the implications might be. Bring that discussion on.

        But that is a different matter, entirely, than saying that “predictions,” or even a “hypothesis” have been falsified by 12 years of 21rst century data.

      • While I wrote the previous, Judith — for the first time — did give a citation. “In the AR4”. You can do better than that for such an enormous report, Judith! — but then you say “out to 2050” — which underlines the very point I am making.

        You reinforce that Leake’s original question refers to a prediction which simply does not exist.

      • I assume that the readers are familiar with contents of the AR4 WG1 Summary for Policy Makers

        http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html

        For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. {10.3, 10.7}

        Since IPCC’s first report in 1990, assessed projections have suggested global average temperature increases between about 0.15°C and 0.3°C per decade for 1990 to 2005. This can now be compared with observed values of about 0.2°C per decade, strengthening confidence in near-term projections. {1.2, 3.2}

        Model experiments show that even if all radiative forcing agents were held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1°C per decade, due mainly to the slow response of the oceans. About twice as much warming (0.2°C per decade) would be expected if emissions are within the range of the SRES scenarios. Best-estimate projections from models indicate that decadal average warming over each inhabited continent by 2030 is insensitive to the choice among SRES scenarios and is very likely to be at least twice as large as the corresponding model-estimated natural variability during the 20th century. {9.4, 10.3, 10.5, 11.2–11.7, Figure TS.29}

      • Chris –

        I vaguely assumed you would be familiar with the predictions of the IPCC FAR. They are quite memorable.

        I was quoting the numbers. BAU = 0.3 degrees per decade, leading to 1 degree 2025. Of course, they say ‘about’ 1 degree which is reasonable caveat but still, a prediction is a prediction.

        http://www.ipcc.ch/ipccreports/1992%20IPCC%20Supplement/IPCC_1990_and_1992_Assessments/English/ipcc_90_92_assessments_far_overview.pdf

      • Anteros –

        I’m sure you saw the last sentence of the paragraph in question.

        The rise will not be steady because of other factors.

        So we have “likely” for 1% with another 13 years to go, and a prediction for an unsteady rise of a certain average over a longer time frame.

        So where does that leave us?

      • Markus Fitzhenry.

        “”Joshua | February 7, 2012 at 7:47 pm |
        IPCC prediction: 0.2C/decade during the first half of the 21st century. This prediction is cited in Leake’s article and also in my post.
        What year is this? How many years in a century?””
        A1. 2012. score 100%
        A2. 100 score 100%

      • Joshua –

        Firstly I’d refer you to my comment below. I think if push comes to shove, that’s where I’ll place my vote – not enough info to say very much at all. Certainly nothing meaningful.

        However, the predictions of the FAR are dramatic, and assessing the reasonableness of dramatic predictions is very different from looking at a noisy signal over an even shorter period of time that isn’t doing very much at all, and asking what the signal is saying for itself

        As I said, it is easier to discern trends if the signal to noise ratio is quite high. The same point is true of predictions. As the FAR predicted a very strong signal it is easier to identify the signal being other than predicted.

        Back to my initial point – I wouldn’t go anywhere so far as to say that it was a failed or wrong prediction. What I would say is that it isn’t doing very well so far. Which isn’t of course saying very much at all.

        I piped up because Chris Ho Stuart was going on about a lack of predictions from the IPCC. Of course everybody forgets that up until 2001, they were spraying predictions around like confetti [ish..]

      • Anteros — I did not say a lack of predictions. I said no prediction for rise over the last decade. That’s because I DO know pretty well what the IPCC reports say.

        The IPCC simply does not have a prediction for short term changes like that. You’ve not shown anything other than the longer term predictions, along with explicit recognition that there are expected to be unpredictable short term variation, on the scale of decades.

        Sheesh!

      • Chris –

        I don’t think you actually read my comment.

        I was responding to this, from you –

        This post starts out by saying it has warmed less than the IPCC predicted. No prediction is cited. That is because it doesn’t exist.

        Now, I said that if a prediction was wanted the FAR could be used – as indeed it can. The last 15 years are relevant to that and I think it is entirely reasonable to say that there has been less warming than the IPCC predicted. Since 1990, or 1995 or whenever.

        It’s not a major point and I don’t think it means very much – as I say elsewhere. But it is true that there has been less warming than the IPCC predicted – I think it is unreasonable to deny it irrespective of caveats and short periods of time.

        It sounds like a desperate attempt to defend something that doesn’t need to be defended

        Why don’t you say that the IPCC changed its prediction from 0.3C per decade to 0.2C per decade in 1995 [which it did] when it realised its estimation of climate sensitivity [among other things] was too high?

      • Thanks Judith… I AM familiar with the AR4, of course; but it should still be cited properly and any predictions quoted more accurately. Leake got it wrong. Your extract confirms it.

        It is, of course, true that warming over the last decade has been less than the long term trend. There’s nothing particular surprising about that, in the sense that we don’t have the capacity to predict at that level with any confidence.

        Understanding these short term changes in rate is an important and legitimate question. It’s a fair guess that the next few years will see a speed up in warming again. TSI is increasing and the ENSO appears to be moving back towards a push in extra heating; but that’s more of an educated guess than a strong consensus supported prediction. There are also other factors, like aerosols, which continue to be very tough to model. We’ll see.

        The main thing I wanted to underline is that Leake was distorting the nature of predictions. As is his wont, I might add.

      • I don’t see how this statement by Leake is misleading:

        “For the critics of climate science this is a crucial point — but why? The answer goes back to the 2001 and 2007 science reports from the Intergovernmental Panel on Climate Change that had predicted the world was likely to warm by an average of about 0.2C a decade. The implication was that temperatures would rise steadily, not with 15-year gaps. The existence of such gaps, the critics argue, implies the climate models themselves are too flawed to be relied on.”

        It would have been more clear to state that this projection of warming from the AR4 applied to the first two decades, such as in this statement of the IPCC

        “For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios.”

        but since we are talking about the period 2000-2011, there doesn’t seem to be anything misleading in Leake’s statement as far as I can see

      • Anteros, you’re still barking up the wrong tree completely. This whole thing is about a warming lull over the last decade. Leake and Judith are both using the latest IPCC reports. You should too. And you should pay attention to the recognition from all the reports that short term changes from decade to decade exist and are not predictable at present, and were not predicted back in 1992 either.

        Understanding short term variations is a good and fair open question.

      • Joshua and Chris Ho-Stuart

        The IPCC projection was fairly clear.

        In AR4(SPM) it was

        For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at 2000 levels, a further warming of about 0.1°C per decade would be expected.

        In the earlier TAR report IPCC was a bit less specific, projecting a range of 0.15°C to 0.3°C per decade.

        What actually happened?

        Greenhouse gases continued to rise unabated, BUT instead of a warming there was a net cooling of the globally averaged land and sea surface temperature anomaly (HadCRUT3).

        For the most recent decade, this was around -0.1°C.

        In Las Vegas, Macao, Atlantic City, Monaco or anywhere else, IPCC would have lost the bet.

        So the IPCC models made a lousy forecast.

        But the real question here is:

        If IPCC models cannot even predict the temperature of the next decade, why are we to put any confidence whatsoever in their ability to project temperatures for the next several decades – or even century?

        Answer: We should be extremely skeptical of any model-based temperature projections cited by IPCC.

        Max

      • Here are a couple of relevant changes from AR1 to AR4, I think.

        (1) Better handling of uncertainty and ranges of outcomes. AR1 mentions ranges, but the expressed prediction as a single number obscures that. AR4 does better.
        (2) CO2 forcing is less. Back in 1992, the CO2 forcing was estimated at about 6.3 W/m^2 per natural log CO2. By AR3 a more accurate value of 5.35 had been obtained, mainly from consideration of the shortwave interactions as well as longwave.)
        (3) Sensitivity estimates haven’t actually changed all that much. The range has narrowed a little, but sensitivity remains something between 2 and 4.5 degrees per doubling; or about 0.5 to 1.2 degrees per W/m^2 forcing.
        (4) There are now more models. In 1992 the model results quoted probably depended overmuch on a GISS model, which then had sensitivity on the high side. (Caveat: transient response sensitivity is probably more useful than equilibrium sensitivity for looking at shorter scales and I’m not so sure of the numbers obtained in 1992.)

        Judith, Leake’s question was phrased as follows: “Why has it warmed so much less than the IPCC predicted?” That’s highly misleading, because in actual fact that IPCC did NOT predict how much it would warm over scales Leake is considering.

        Leake also asks:

        Overall, then, the world has got slightly warmer since 1997. Perhaps the real question is: why has it warmed so much less than was predicted by the climate models?

        That also is just silly. Climate models show variations over these time scales just like the real world does. The difference is that there’s no correlation in those short term variations. One model might have a slow down from 1990 to 2000; another from 2015 to 2025. The models predict, if anything, that you are going to unpredictable short term increases and decreases.

        Leake includes sensible quotes in his article, but he continues to make — and emphasize in his headline — the absurd implication that models, or the IPCC, is making predictions that clash with the observed small scale slow down. That’s just flatly false.

        I repeat. Examining and explaining decadal scale changes is a perfectly good and sensible open question. The phenomenon is real. The problem is real.

        The idea that it violates an IPCC prediction is not real.

      • I don’t see how this statement by Leake is misleading: – JC

        “For the critics of climate science this is a crucial point — but why? The answer goes back to the 2001 and 2007 science reports from the Intergovernmental Panel on Climate Change that had predicted the world was likely to warm by an average of about 0.2C a decade. The implication was that temperatures would rise steadily, not with 15-year gaps. The existence of such gaps, the critics argue, implies the climate models themselves are too flawed to be relied on.”

        Yes, it’s misleading, and Leake gives the game away himself; “…The implication…”.

        Even Leake has to concede it’s only implied.

        And when did the concept of ‘average’ become so hard to understand??

      • Latimer Alder

        I advised Chris H-S earlier to stop digging as he was in a deep hole.

        On reflection, this was not good advice. For it is stupid academic squabbles like this that continue to harm the reputation of climatology and climatologits in the public mind.

        Keep on squabbling guys. Whatever the exact weight put upon appendix 7 subsection 3 caveat 7, the general public have been led to believe – by constant propaganda from climatologits and their political allies for a decade or more – that we live in a dangerously warming world and so must immediately make sacrifices and do counter-intuitive things for the good of the planet.

        I do not recall that the take-home message of AIT was that warming was going to be a sort of on/off/maybe next year phenomenon but that it was happening now was real and was dangerous.

        Maybe it is different in the US, but in the UK at least we have a well-founded and deep suspicion of salesmen who get you to sign up to something for its many benefits, and only discover years later that the small print buried deep in the Appendix means that the policy doesn’t apply when you need it most.

        So Mr Chris H-S, keep on pointing out that on a close reading of subsection 7, clause 7 para 16 (as amended by subsequent resolutions as needed) means that what the IPCC said wasn’t exactly what they meant and so they have suddenly invented academic wriggle room. Shout it loud from the rooftops! Writhe and rend your raiment about how tough the press are on you and how a journalist this time hasn’t presented your case in the most favourable light.

        Then point me to all the writings in the last twenty years where you and colleagues have been equally loudly shouting that warming was only going to be intermittent, that the idea of ever-increasing warming was wrong, that Al Gore had vastly overstated the case and about how the sceptics got that right.

        When you can produce an extensive library of such documentation I’ll be happy for you to consider yourself vindicated.

        But until then, no deal.

      • steven mosher

        Chris,

        If the IPCC does not intend people to believe that they have made short term projections, then they need to change the way they draw graphs.
        If they truly believe that the next 10 years are a total mystery then they need to stop drawing graphs that tend to convey that message.
        Its not that hard to be clear about this. They go the extra mile to make
        sure that some graphs are not misunderstood. they should extend
        this to all their presentations. If they truly have no idea what the next 10 years will hold, but are confident about 20 years from now, they should
        clearly say so when they present charts

        the IPCC publsihes a chart like this: Look at the care they take in the legend.

        http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-10-4.html

        “Figure 10.4. Multi-model means of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th-century simulation. Values beyond 2100 are for the stabilisation scenarios (see Section 10.7). Linear trends from the corresponding control runs have been removed from these time series. Lines show the multi-model means, shading denotes the ±1 standard deviation range of individual model annual means. Discontinuities between different periods have no physical meaning and are caused by the fact that the number of models that have run a given scenario is different for each period and scenario, as indicated by the coloured numbers given for each period and scenario at the bottom of the panel. For the same reason, uncertainty across scenarios should not be interpreted from this figure (see Section 10.5.4.6 for uncertainty estimates).

        They took care in the legend to advise people NOT to interpret discontinuities in the lines. Did they take care in the legend
        to tell people not to take the short term lines seriously? No.
        If they really have no clue about the next 10 years, then they need to show that and explain that.

      • Steven mosher, I don’t see the problem with the graph you mention. It includes a shading envelope that indicates a range of possibles. It has a horizontal scale on which ten years doesn’t even show (the tick marks are 50 years apart). You look and you immediately see that the increase over 10 or 15 years is small by comparison with the shading width.

        Communication can always be improved, and I don’t want to get sucked into defending the IPCC as perfect communicators. I’m simply saying that Jonathan Leake was incorrect to speak of the IPCC making predictions that conflict with the lull in trend in the last 15 years. Inferring unstated predictions from a graph is invalid, whether the legend warns against this or not.

      • Latimer,

        The IPCC, as Chris points out, makes it clear that warming is not expected to occur in a linear fashion. This point is also made time and time again by climate scientists. If the general public doesn’t understand this then it might be in part due to poor communication by climate scientists and journalists, but what the general public might believe is not the issue here – this is a forum for people who actually take an active interest in the subject so there should be an expectation that they are rather better informed than the average man on the street, especially if they are going to make confident pronouncements about the supposed flaws in the IPCC position (and other things). So in order to argue about whether the IPCC is right or wrong on on the subject its necessary to make a bit of effort to understand what the IPCC is actually saying. Of course if the purpose is simply to find reasons to say the IPCC is wrong then I guess it’s not so important.

      • AA,

        And communication is a two-way street…..issues at the receiving end can, and do, exist independently of the sender.

      • Michael,

        Yes, absolutely.

      • This might be some help to those agonising over how an average of 0.2C per decade over a long period might not manifest as a 0.2C increase every decade.

        http://www.agu.org/pubs/crossref/pip/2011JD016328.shtml

      • Why don’t you say that the IPCC changed its prediction from 0.3C per decade to 0.2C per decade in 1995 [which it did] when it realised its estimation of climate sensitivity [among other things] was too high?

        It would be completely incorrect to say that, so there’s a good reason ;) The best estimate and range of climate sensitivities used in the SAR are exactly the same as in the FAR. The difference in the projections is due partly to lower emissions scenarios (less CO2, methane and CFCs in particular), and partly to the introduction of aerosols into the scenarios.

      • @andrew adams

        ‘The IPCC, as Chris points out, makes it clear that warming is not expected to occur in a linear fashion. This point is also made time and time again by climate scientists.’

        I’ll look forward to seeing the evidence to support your assertion that the point is made ‘time and time again’ by climatologists. Becasue it certainly doesn’t gel with my memory. Seems to me that the emphasis on this point has only recently been remembered once it has become ever clearer that the temperatures are stubbornly failing to do what they are told.

        So I’m sorry, but without further confirmation of an extensive library of quotations and presentations where this point has been drummed home, I have to provisionally put the ‘time and time again’ assertion in the same pigeon hole as Tony Blair’s ‘as I have said many times before and made my position absolutely clear’.

        This, of course, was pure Blair speak for ‘f..k me I’ve never thought of that before and need a second or two to dream up something plausible’.

        And you might want to reflect on this helpful remark from Richard Betts of the Met Office and teh IPCC, commenting today at Bishop Hill

        http://bishophill.squarespace.com/blog/2012/2/7/information-commissioner-on-academic-data.html?lastPage=true#comment16812437

        He says:

        ‘I think the problem is that an own-goal has been scored in the communication of climate model projections. They are normally presented with the results smoothed over time, or as decadal means, for clarity of presentation. This has meant that it was not at all obvious that natural variability is important in the the shorter term’

        which is a polite (as ever from Richard) and face-saving way of saying ‘Its a fair cop, guv. You’ve got me bang to rights’

      • Paul S [8th@8.26am] –

        Fair point.

        I can’t argue with that so I’d better take it on the chin.

        Thanks for the clarification.

      • Chris Ho-Stuart: Communication can always be improved, and I don’t want to get sucked into defending the IPCC as perfect communicators.

        Taken on the whole, that’s what you have done. Not that IPCC was perfect, but that it was so clear that it was nearly perfect.

      • Chris hijacked my post, but the point remains. Multiple hypotheses are in play. If the AGW hypothesis advocates claim it will take decades to resolve this issue, then so be it. Suspend all action in the interim. How is 2040 for a decision date? Sorry, but the absurdity is showing.

      • Latimer,

        Are you serious? Read Chris’s arguments above – are you really saying that you have never seen them made before? Maybe you should try actually listening to what scientists say and giving their arguments proper consideration rather than automatically dismissing them out of hand, then they might come as less of a surprise next time.

      • Latimer Alder

        @andrew adams

        I have read chris h-s’s arguments. And pretty thin they are too

        1. They seem primarily to rely on appealing to the ‘disclaimers’ that the IPCC published…like those bring bits on TV ads that say things like ‘your results may differ’, ‘applications subject to status’, ‘no guarantee express or implied’, and most importantly

        ‘this advert is probably a load of s**t but we hope you won’t notice’.

        Any organisation that has to rely on such get-out clauses to counter charges that their product or service does not remotely perform as advertised merely shows that they are disreputable and not to be trusted. More at the shoddy end of e-Bay rather than the John Lewis of scientific organisations.

        2. He then proceeds via some devious route to try to pull more wool over our eyes. That legalistically, the IPCC is only the summariser of information provided by others. So any mistakes in the basic data aren’t the IPCC’s fault and it is, therefore, completely blameless for anything published under its name.

        Which might just possibly have some traction if the group of people doing the summarising were completely independent of those doing the basc research. But they aren’t. They are the same people. By definition. The IPCC makes a point of picking the people who are its authors from exactly the same community as those doing the research.

        So when, for example, researcher PJ (as we may call him) writes that MM’s paper on some old teleconnection shit is the hottest thing since sliced bread and conclusively proves that Thremageddon is expected two weeks come next Michaelmas, he is reviewing his long-standing research buddy’s work. No wonder that he gives a seal of approval. And, surprise, surprise we will find MM saying nice things about PJ also.

        The IPCC can’t just wriggle away from its responsibility by pleading that the review was written by an ‘independent guy, and any consequences are nothing to do with them.

        If this is really news to you, please study Donna LaFramboise’s lovely tome ‘The Delinquent Teenager’. Great stuff.

        3. Timing

        Even with all the deficiencies above, I’d have a bit more sympathy if people like Chris H-S had a demonstrable track record of loudly shouting that the trend would be intermittent going back some years.

        And they haven’t.

        Instead we’ve had such lunacies as the Mad Woman from the Met Office going on national TV to assure us that last years cold and snowy winter in the UK was a direct consequence of global warming. I don’t recollect H-S – or indeed yourself – protesting that she was wrong and that this merely showed that warming has paused.

        We had the man in 2000 telling us that because of global warming, snow in UK would be a thing of the past. I don’t recall his immediate rebuttal that he had been misquoted and that really it might be a whole generation before any such effects came into play.

        You claimed earlier that climate scientists have made this ‘intermittency’ point ‘time and time again’. And I asked you to provide some documented verification that they have indeed regularly and firmly stressed this point.

        So far you do not seem to have been able to. Maybe it is still in preparation?

        But hey, what do I care? Shenanigans like this word-chopping a la Ho-Stuart merely serve to reduce the climatologits credibility yet further. As Betts from the Met Office so nicely put it:

        ‘It’s been clear to me for a while that the field of climate science has a lot of work to do in regaining trust’

        and stuff like this makes that task ever harder.

      • Latimer,

        I don’t consider myself to be an expert by any means but in the few years I have been taking an interest in the subject of climate change I have tried to educate myself as much as possible about the various scientific arguments surrounding the subject, and one thing that has constantly been impressed upon my mind is that when there is a long term trend caused by increasing GHG levels there will periods when it is masked (or accentuated) by short term natural variability. And that this is reflected in individual model runs but as the timing of events such as El Nino/La Nina, volcanic eruptions etc. is unpredictable when projections are made based on ensemble runs then they will tend to average out and the projection will show a fairly steady trend.

        Now funnily enough I don’t bookmark every interesting web page I visit or every informative blog comment I see, but here are a couple of examples

        http://thingsbreak.wordpress.com/2009/09/10/of-moles-and-whacking-climate-models-didnt-predict-this-lack-of-warming/

        http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/

        (there are loads more examples at RC)

        but it’s a point that has come up countless times in discussions on the various climate blogs I visit, including this one. I simply can’t believe you are unfamiliar with this argument. And to point it out isn’t to seek some kind of disclaimer or get out clause, it is an absolutely valid point and an essential part of the argument about how the IPCC projections compare to actual observations. As I said above, even if (and I’m not saying this is the case) scientists have been poor at communicating this point to the public there is no excuse for anyone who actually takes an interest in the subject to the point where they feel competent to make confident pronouncements on the state of climate science and the reality or otherwise of (C)AGW not to be aware of it. If you want to pass judgement on an issue and have your opinion takes seriously you have a responsibility to actually make an effort to understand it.

        Regarding David Viner’s comment I think that if he was quoted correctly then it was a silly thing to say, although the kind of winters we have had in the last couple years have certainly been less common than they used to be. I’m not familiar with the particular comment from his female colleague which you refer to but the notion that global warming and its side effects such as the large reduction in the extent and volume of arctic sea ice could have a significant impact on atmospheric circulation patterns is one I have seen raised on occasions and doesn’t seem inherently implausible. It is interesting that the last couple of winters when we in the UK were suffering unusually (by recent standards any way) severe conditions other parts of the NH such as Greenland and eastern Canada were enjoying unusually warm weather. I find it interesting that you automatically assume her to be incorrect, I wonder what you base this assumption on.

      • Chris

        The point of the matter is quite simple.

        If IPCC cannot even project temperatures for one decade into the future, there is no reason to believe that they can do so for several decades or even centuries into the future.

        Figure 10.4 goes to year 2300! How totally absurd!

        The problem is the “slope of the line”, Chris (i.e. the model-derived 2xCO2 climate sensitivity used for making the projection).

        If this were corrected downward to around 1.0 to 1.5C, instead of 3.2C on average, the projections would fit fairly well.

        Incidentally, this range is also the observed long-term CO2 temperature response since 1850.

        Max

      • max:

        If IPCC cannot even project temperatures for one decade into the future, there is no reason to believe that they can do so for several decades or even centuries into the future.

        Questions about the implications of temperature trends to the validity of IPCC predictions, and questions about the utility of wide error-ranges aside, the illogic of that statement is just stunning.

        Even if I can’t predict how many times you will post comments at Climate Etc. in the next hour, I can predict that in the next week you will post somewhere between 1 and 1,000,000 comments.

      • @andrew adams

        @chris ho-stuart

        AR4 summary for policy makers.

        ‘For the next two decades, a warming of about
        0.2°C per decade is projected for a range of SRES
        emission scenarios. Even if the concentrations of
        all greenhouse gases and aerosols had been kept
        constant at year 2000 levels, a further warming of
        about 0.1°C per decade would be expected’ (p12)

        In a big box highlighted by a tasteful background colour to stand out from the rest.The first and most important box on the topic ‘Projections of future changes in climate’

        This is the message that the ‘climatology consensus’ wanted the politicians and the public and the press to take away with them. This was their projection. Even if they read nothing else at all about climate change this is what they wanted Blair and Bush and their officials to know. This what they expected to be included in the front page article in the London Times and the NYT and the WSJ This was what they wanted to be the discussion point on the TV and the radio.

        No caveats.No ifs or buts. No ‘your results may differ’. No cautionary notes. A definite unequivocal statement. The summation of 20-odd years work by thousands of people and tens of billions of dollars of public money

        If the IPCC had wanted to give a different message, there are many other ways it could phrased this paragraph. But it didn’t.

        My case rests

      • Latimer,

        Leaving aside for now the question of how effectively the IPCC communicated the expected nature of future rising temps, would would be your expectation based on your understanding of the science?

        Assuming for argument’s sake that the IPCC’s calculation of the long term trend was broadly correct, would you expect temps to rise in a more or less linear fashion or would you expect there to be periods when temps were flat or even falling?

    • Steven Mosher

      correct. the ipcc does not do science. its documents are not scientific. I think
      that citing AR4 as a source is no better
      than citing wikipedia. further if we want
      to evaluate ipcc documents the standards
      we need to apply are standards like

      accuracy
      openness
      transparency
      traceability

      • Steven, Dr. Curry, there is a point to what Fred and Chris have been about. But I don’t think they understand what it means in terms of the discussion here. From the figure you and Steven posted and the write up in AR4, IPCC claim is that by 2030 it will be such and such, and that the anthropogenic influence will be twice the natural variation. It is true that the scenarios are from 2000, so using 2000 is a good choice. At 2030, the anomoly is expected to be about 0.7 C, but starts at 0.2 for year 2000. 1/3 of that is .167 C That offfset is the maximum that natural variability can account for at 2030. The estimate for 2011 is about .5 on the graph. So, accounting for all the natural variance for the first 11 years since 2000, the anomoly has to be about 0.333 C. But the trend from 2000 is showing us at about .28 C at this time on the same baseline, unless I have been wrongfooted.

        So maybe saying what Leake said is not exact, but it is accurate. indicating the models are running high about 0.016 C per year. This agrees with other posters such as Lucia, in general and approximately. So, taking into account what was actually said at 10.3 and 10.4, in AR4 it cannot be claimed at present that the models have not been “falsified.” And as pointed out, it would be expected at such a short number of years that such could occur, and that the final trend could actually be higher than what the AR4 stated. It is too early to claim victory, but not too early to point out that the odds are that the models are running high compared to what the IPCC actually stated.

    • steven mosher

      “(4) There are now more models. In 1992 the model results quoted probably depended overmuch on a GISS model, which then had sensitivity on the high side. (Caveat: transient response sensitivity is probably more useful than equilibrium sensitivity for looking at shorter scales and I’m not so sure of the numbers obtained in 1992.)”

      hmm. ModelE has a sensitivity of 2.7. Not sure what you are refering to

      • This model which turned out to have a lower sensitivity was developed around 1997 I think. If you read one of the Hansen 1997 papers he talks about using a new model with a lower sensitivity. Before that it was something like 4- 4.5ºC.

        However the projections in the FAR were not very dependent on the spread of model sensitivites – the ‘best estimate’ was produced by comparing model experiments with observations and scaling to infer a climate sensitivity of 2.5ºC (2.1ºC if compared to current 2xCO2 RF formulation).

      • There are many trends found in nature and the works of man that have the characteristics described for temperature. They are sine waves of varying amplitudes with sawtooth irregularities.

        Should the IPCC have used better description of the waveform their models create? Yes, but I’ll bet they didn’t really expect general readership to get involved.

        If the frequency of the temperature trend is the long term forcings (mostly from things that happened to the ocean 800 years ago) and the sawtooth irregularities are what we can measure with satellites, ARGOs and the occasional thermometer at the airport, this waveform looks like a gazillion (pardon the technical description) others.

        If you are convinced that you have separated the sawtooth irregularities from the actual signal, then you can set them aside when doing major calculations.

        If on the other hand there is some uncertainty as to what forms part of the sawtooth variation and what is part of the underlying signal, you need to pay pretty close attention to all components of the information you receive.

        Which I think is a good description of where we are at the moment.

    • Chris is now deploying the AGW wack-a-mole defense: When things are going the way believers want, the IPCC is the paragon of climate science and those who dispute that are denialist scum. When the IPCC gets in trouble, the same believers claim it never even makes a prediction, and those who claim otherwise are liars.

    • Chris Ho-Stuart: It is also a misrepresentation of what the IPCC does to speak of IPCC “hypotheses”. The IPCC is not a research body. They don’t do scientific work. They summarize it. They make statements with associated confidence levels, based on the combined work of a lot of scientists, but these are not in the form of a “hypothesis”, but a conclusion. Whether you agree with them or not, the distinction matters.

      That is nonsense. The hypothesis is there whether you want to assign it to the IPCC or not.

      Short term variations like this ARE a matter of scientific interest and hypothesis and competing ideas. They are not a matter of a clear consensus. And neither does the IPCC make strong claims or hypotheses on them — other than the statement that they ARE comparatively short term and that we expect the longer term trend to continue upwards.

      That is a nice clear statement of the hypothesis. If the short-term lower-than-predicted temp records continues, then the hypothesis will be discredited. Right now, all we can say is that the prediction based on the hypothesis does not have a demonstrated record of accuracy.

      • Matt –

        Right now, all we can say is that the prediction based on the hypothesis does not have a demonstrated record of accuracy.

        If there was no prediction for the first 12 years of the 21rst century, then it seems a bit misleading, in 2012, to say that we do not have a demonstrated record of accuracy for predictions of average temperature change for the 21rst century, or through 2050, or even through 2025.

        Of course, I would expect that if temperatures during these 12 years had increased at a rate consistent with the predictions of average increase through longer time periods, some would say it was evidence that the predictions were accurate.

        The predictions are information. The record of temperature trends over the past 15 years is information.

        The implications of the predictions that were made is worthy of discussion. And discussion of the meaning of the trends and predictions, and implications, without a mention of the caveats that were made:

        “The rise will not be steady because of other factors.”

        is not particularly useful. I would rate it at about on the same order or meaning as a discussion of the hypothesis without discussing the temperature trends subsequent to predictions that were made.

        So the question I would have is why didn’t Judith or Leake mention the caveat the IPCC put in right there along side the predictions they (Judith and Leake) spoke of?

      • Joshua: If there was no prediction for the first 12 years of the 21rst century, then it seems a bit misleading, in 2012, to say that we do not have a demonstrated record of accuracy for predictions of average temperature change for the 21rst century, or through 2050, or even through 2025.

        Whatever you wish to call them, they have no demonstrated record of accuracy. They were presented to the public as though they were accurate descriptions of what would happen imminently and persistently without immediate action. Only after it was clear that they were wrong was there the increased “clarity of communication” that they did not really rule out 12 years of nearly no increase in mean temp, and that they were not intended to tell us what would really happen without action.

        What’s more, it’s still extremely important to act now (we have been warmed) because the “non-prediction” now is that the non-warming can’t last, though the warming may not be “steady” by some post-hoc redefinition of steady.

        Chris Ho-Stuart has been attempting to define “non – steady” in a way that no one took it when the IPCC report was written.

    • Latimer Alder

      @hris h-s

      In the eyes of the general public you are making a distinction without a difference.

      We/they do not really give a toss about whether the declaration is made by the IPCC in its capacity as the IPCC or by the individual members of the IPCC in their individual capacities and then summarised by those self-same members in their capacities as members of the IPCC . It doesn’t matter one jot which hat they are wearing at the time. They are all climatologists..and (dare I say) members of the consensus.

      The crucial point that you are all dancing around and refusing to confront is that the idea of ‘Trust us, we’re climate scientists’ has taken another huge battering in the public mind. The last two years – since the Blessed Liberation of the Climategate 1000 and the Gods dumping snow and other s**t all over Copenhagen – has seen endless further revelations that the theories are ‘incomplete’ (at best) and that climatologists are no more trustworthy than the average Joe Sixpack,…and in some cases quite considerably less so.

      And – in Europe at least – several unusually harsh winters explained way by the faithful as yet more evidence that global warming is real and that we’re all freezing because the planet is getting dangerously warm (?) are in danger of turning you all from the high status of ‘trusted advisers’ a few years back into laughing stocks.

      You should be very worried by this, because, government funded as you all are, when hard financial times come – as they have – the easiest way to make cuts is to take away money from the softest targets. And climatology is now one of those.

      I am just amazed that you collectively have no response other than to reassert that you are right and deserve to be trusted. And now to start legalistically rewriting history when your predictions don’t turn out right. I don’t remember there being any such uncertianties when you were proclaiming ‘The Science is Settled’ and other such BS.

      And it is not good enough to say individually ‘it wasn’t me guv’. ‘Al Gore misrepresented my views’, ‘We always knew that the warming would stop’ and all that. Until a few weeks ago you were all proudly boasting about how much of a consensus there was. It was (occasionally) your ‘killer punch’. 97% of you all agreed. The flipside of 97% agreement is that 97% of you also have to take the rap.

      So keep on arguing abou teh exact wording of who said what to whom and when – and whether they were cating in their individual capacity or collectively or as memebers of the consesnus. It really doesn’t matter any more. The general public will look on with amused bewilderment as you try to argue that black iwhite that hot is cold and that you deserve out trust.

      From Hero to Zero is but a short downhill slide. And you guys are starting your descent and accelerating like the slope of a hokey stick.

      • Markus Fitzhenry

        “The general public will look on with amused bewilderment as you try to argue that black is white that hot is cold and that you deserve out trust.”

        I think you are absolutely right Latimer. They will wonder why Climatology measured average temperature at surface yet with solar fluctuations of Wm2 at top of atmosphere in the mismatch. Peaches and plums.

        If they had only measured incoming solar energy percentage of distribution through a atmosphere with a mixed albedo.

        Anyway, Bob Fernley-Jones recons it works something like that.

  3. They make statements with associated confidence levels,…

    Would that Judith would do likewise on a more consistent basis.

  4. In complete contrast to the point I want to make, RSS have published in the last 24 hours their data showing precisely no warming at all since 1997.

    They also, for those who have been waiting to celebrate for a long while [genuine alarmists who want to be proven wrong] show that for the last 15 years – since the beginning of February 1997, there has been global cooling.

    Perhaps this isn’t in contrast to my point after all, which is that such things are essentially meaningless. The globally averaged temperature anomaly has a tiny modicum of virtue solely because there is precious little else. To quote thousandths of a degree is insanity, whereas a tenth or two is just a basic misunderstanding of noise, averages, chaotic systems and the vaguest of measuring coverage.

    It seems to me to make some sense to say that the 20th century saw a rise in temperature of approximately three quarters of a degree. But that seemingly included 3 30 year periods that were different to what came before and after. And even then, these observations are barely discernible from a realistic distance.

    It strikes me as a little irrational – though very human – to attempt to extract genuine meaning from 15 years of data. A third of a century? Possibly, maybe, just about – depending on the strength of the signal, but tempting as it is, I think staring hard at messy little bits of noise (from less than half of that time) hoping to see signs and wonders is a little too much to ask.

    Check this out from Richard Lindzen – not because it is partisan [it isn’t, in this context] but because he uses visual means to make the very same point as I have tried to do.

    • Thanks, Anteros, for the link to the excellent presentation by MIT’s Professor Richard Lindzen!

    • Anteros

      Professor Lindzen’s brief presentation puts it all nicely into perspective.

      I hope Joshua and Chris take the time to see it.

      Max

      • It sounds like they all had a laugh on us too, at 2:13… who said scientists don’t have a good cents of humor.

    • Vaughan Pratt

      Very compelling visuals in the Lindzen video, Anteros, thank you for posting that.

      However one has to wonder whether there was anyone in that audience both competent in statistics and willing to challenge Lindzen on the following omission from his presentation.

      If each point in the right slide is obtained as the average of 100 more or less normally distributed points in the left slide, the errors bars shrink by a factor of sqrt(100) = 10. Lindzen did not mention this.

      I took Lindzen to be implying, both by this omission and his subsequent remarks, that in fact they don’t shrink, and that it is therefore misleading to zoom in on the right by a factor of sqrt(n) (n the number of points on the left producing one point on the right) without also increasing the length of the error bars in proportion.

      Now imagine that McIntyre was in the audience. Would he have raised this point with Lindzen at question time, or would he have passed over it in silence?

      Now further imagine that the speaker had been Mann instead of Lindzen, with the exact same talk, slides, and emphases, and ask again what would McIntyre have done.

      It would be a very interesting poll to see who believes McIntyre would be just as likely to have raised this point with Lindzen as with Mann, and who believes otherwise. Especially if McIntyre himself were among those polled.

      As the one who posted this video, Anteros, what do you think?

  5. In a better world you would think that slide would settle it.

    This isn’t a better world, it’s a declining one at the moment. AGW advocacy is evidence of decline.

  6. Interesting post Dr Curry.

    Non linear and non ergodic systems do not produce data that can be used for prediction. It may be possible, however, to separate some of the Earth systems which interact to produce climate and climate change and that some of these systems may well prove to be ergodic and any non linearities may yield to discretisation techniques.

    It may well be the case that only the systems that produce forcings eg volcanic eruption, solar winds, sunspot activity and the like could be non ergodic but still capable of yielding scenarios for climate modelling purposes.

  7. I need someone much smarter at statistics than I am to explain the real differences between II and III in the opening post

  8. “IMO, the standard 1D energy balance model of the Earth’s climate system will provide little in the way of further insights; rather we need to bring additional physics and theory (e.g. entropy and the 2nd law) into the simple models, and explore the complexity of coupled nonlinear climate system characterized by spatiotemporal chaos.”

    No doubt about that, even a basic 3D model would years ahead of the game.

  9. Lack of predictability is not a challenge of H3, it is an intrinsic feature of chaos. This limit is what we should be trying to establish, not H1 sensitivity.

  10. Markus Fitzhenry.

    The whole of Climate Chaotic Instability: Statistical Determination and Theoretical Background assumes a partial argument. Rather religiously actually. It offers three hypotheses that explain 20th century climate variability and change, nothing about 21st century hypotheses though. It discovers that only the three investigated scenarios have merit in the scientific debate of atmosophere.

    What is it’s purpose, if only to reflect on a possibly invalid theory? The consensus is very much alive. No mention at all of any contrarion perspective.

    It allows only three scenarios in the mix. What about Macro-climatology?
    As there are no verses in the book about it, scientists don’t have to considerate it and can remain in a bliss of rhetoric.

    Is Climate Science such a religion, it must issue fatwas against scepticism and logic. I can easily understand how how difficult it was for Galileo to shift an incorrect scientific paradigm.

    Climate Scientists can fall of the end of the earth whilst reason will remain firmly planted on this beautiful mother of a Earth.

  11. If we have a predicted rate and we have real data, can we not work out the minimum degree of ‘noise’ in the system. If the model states 0.2 degrees per decade, then true-modeled give us the current noise. However, from this random noise we can work out the likely hood of different temperature swings; again based on true-model. We can then see if we can fit 1900-2012 without a slope and see the probability of it occurring at random.

    • Markus Fitzhenry.

      “a predicted rate – If the model – then true-modeled – again based on true-model – see if we can fit”

      The only models worth consideration that I know, are the blonde ones.

    • A very sensible idea.

      And all scientists must always be open to alternative hypotheses and explanations of the data, as this post illustrates. The more time goes on, the less confident we are in the main IPCC hypotheses.

      Doing the data analysis you suggest would help further the science tremendously. Hopefully someone is doing it somewhere.

  12. In order to derive a temperature shenomaly dT, one needs to know an initial temperature T1 and an end temperature T2.

    So I ask, what was the global temperature T1 in the year 1750, 1850, 1900 (you choose). How was it arrived at and what a shmuck you are if you think I’m going to accept an answer to hundreths of a degree.

    AGW stands on the pillars of a SHMUCK SHENOMALY.

    Highly educated doctors and PhDs but not an ounce of commonse sense amongst them. It’s bloody well embarrassing.

  13. Obviously they should have put error bars on the 0.2 degrees per decade. If you use two years a decade apart, and the interannual variability is several tenths of a degree, you are not going to get an 0.2 degree trend very accurately. I don’t know how people are using 1997 to compute a trend, but they should average at least a few years on each end to reduce the error bars to something where 0.2 degrees would be detectable. I always recommend at least a 10-year average which gets rid of solar cycles too (hint: not good starting at a solar max and ending in a min 15 years later). Using decadal averages the last decade was 0.15 degrees than the previous one, and the error bars are actually smaller than the trend.

    • Jim D

      I agree with you that IPCC should have put error bars on the 0.2 degrees per decade.

      Since the most recent 10-year period shows cooling of -0.1 degrees per decade, the error bars should have been +0.2+/-0.3 degC per decade.

      Or, more accurately, cooling of -0.2+/-0.1 degC per decade.

      Right?

      Max

      • Statisticians, and I’m not one, should realize that when the detrended standard deviation is 0.1 degrees (which it is close to), you can’t get an accurate trend of tenths of a degree per year from two years separated by ten years. A zero trend is just as likely as an 0.2 degree trend if the real trend is 0.1. Averaging more years reduces the standard deviation by the square root of the number of years, so by the time you average ten years the standard deviation for a decade is down to 0.03 degrees. Now you can get a trend from two decades with much smaller error bars and a trend of 0,1 degrees would be more likely to be seen.

      • Jim, averaging more years does not reduce the SD. You are confusing years with samples of the same thing.

    • smoothing? Why not just examine that actual data using a method designed to detect anomolies that does not reduce the information content?

      Cusum is your friend

      http://books.google.com/books?id=cTwwtyBX7PAC&pg=PA192#v=onepage&q&f=false

      http://www.cs.tamu.edu/academics/tr/tamu-cs-tr-2007-1-2

      • What is special about an annual average? A decadal average is just as useful and has smaller error bars in addition to removing sunspot cycles quite well. Maybe you prefer the raw daily or hourly data?

      • Averaging always loses information. A decadal average loses ten times as much as an annual. And a decadal average is worthless if you are interested in the behavior within that decade.

  14. Models, shmodels.

    While there may be some die-hards who haven’t gotten the word yet, we know now that our climate cannot be successfully modeled.

    Too many uncertainties

    Too many unknowns

    Too much chaos.

    For a good treatise on WHY model predictions – especially those covering longer time periods – do not work, and why “experts” have a worse chance of predicting something correctly than “non-experts”, read Nassim Taleb’s The Black Swan.

    Max

    • Manacker, You convey a mix of Luddite, Malthusian, and Cornucopian perspectives in the way you convey exactly what you would like to see. This opinion of yours is on the Luddite side.

      Taleb’s book is not a dire warning of hopelessness. It is in fact a motivating influence and call-to-arms for engineers, scientists, mathematicians, and statisticians to get their act together. No one should be constrained to using Normal or Gaussian statistics any longer for environmental models. The natural world contains many fat-tail behaviors that were previously ignored because the Normal thin-tail statistics was the way that we were taught.

      That’s what Taleb was saying. Uncertainties are bigger than we think, but it has no relevance to actually making predictions. You just have to use the correct fat-tail statistics.

      Unfortunately, as Taleb wanted to sell books, he didn’t put a lot of math details into The Black Swan. It was left to the astute readers to figure this out. I use Taleb’s ideas heavily and they should be part of any uncertainty analysis toolbox.

      • “Cornucopian”? Copernican?

      • WHT

        Classifying my statement into some arbitrary categories you have picked out does not change the fact that the models cited by IPCC were unable to correctly project the temperature for the first decade of this century, as I stated (and as Jonathan Leake points out)..

        That is the issue here, Web.

        Climate models cannot predict climate, because they fixate too myopically on human forcing while ignoring or simply not understanding everything else.

        My question to you (and it’s a serious question, Web):

        Since climate models have demonstrated that they are unable forecast our climate one decade into the future, should we have any confidence in their ability to project climate changes over several decades?

        A simple YES/NO answer is OK, followed by a one sentence reasoning for why you chose this answer.

        Max

      • WHT

        Congratulations on having read Taleb’s book.

        So did I.

        It was not about climate change at all – it was simply about the utter futility and absurdity of trying to make long-term predictions in chaotic systems with more unknowns than knowns..

        No. There is not a lot of “math” in the book (Taleb is not a “nerd” – and the book wasn’t written for “nerds”).

        But there is a whole lot of “common sense”, which (unfortunately) is missing in the projections of future climate change being sold by IPCC, starting with the failed projection of 0.2 degC warming for the first decade of the century (topic of this thread) and going on to the forecasts of 1.8 degC to 4.0 degC warming by the end of this century.

        Max

      • Latimer Alder

        Just a simple question

        If climate models are no good at predicting the future even ten years out, what use are they at all? Why do we spend any money at all on funding them and their staffs?

        It may be that there are some good reasons out there…but they haven’t yet come to my notice.

      • If climate models are no good at predicting the future even ten years out, what use are they at all?

        I think the word ‘even’ here suggests you are leading yourself astray in a belief that short-term prediction should be easier than long-term prediction. Analogously, you could ask why quantum mechanics is useful if it can’t predict the outcome of a single experiment.

        Short-term prediction carries a couple of major complications I can think of right now:
        1) dependence on initial conditions to define evolution of internal variability mechanisms. Similarly to weather forecasting, efforts can be made to setup a model to match initial conditions at a certain point in time but they are likely to break down pretty quickly because we lack the quantity and quality of data to be precise enough in the setup (and possibly because the chosen model does not accurately produce variability similar to that observed on Earth).
        2) possibility of influence from unpredictable factors (volcanic eruptions, solar variability).

        These factors carry less importance on multi-decadal timescales, in a probablistic sense at least. A string of very large volcanic eruptions or long period of extremely low solar activity would carry some significance but are not likely occurrances within the frame of, say, 50 years. I can’t remember where but I’ve seen it discussed that a ‘sweet spot’ for climate projections would be about 30-50 years. Shorter than that, unpredictable factors can have a considerable effect. Longer than that, the particular scenario (i.e. what humans will do) becomes an important factor and there is also the potential for dynamic ‘surprises’.

        On a more general point, projections of the future are just one possibility for use of GCMs. They are also indispensible tools for exploring factors which affect climate.

        There’s a useful discussion of decadal model predictions here.

      • Latimer Alder

        @paul s

        ‘you could ask why quantum mechanics is useful if it can’t predict the outcome of a single experiment’

        That you phrase the question that way shows that you don’t know much about QM.

        But my question about models still stands. Let me phrase it another way.

        We have spent something like $100 billion on climatology in the last 25 years. The purpose has been for us to understand better what will happen in the future wrt climate. And the final outcome of all that $100 billion is the climate models. Everything else is just part of the ‘scaffolding’ to that goes into the construction of those models.

        And it is apparent that they don’t work very well – if at all – on the stuff we want them to do. It is even beginning to seem likely that they can never be made to do the things we would like them to do. That the nature of the climate system means that it is as insoluble a problem as is the behaviour of an individual wave/particle in teh QM world.

        So, before we write off our $100 billion as just money wasted, I wonder if there are any side benefits of these models that we can point to and say ‘well at least we got ……’. Much like some think that going to the moon was a total waste of money but that we got teflon saucepans as a spin off.

        So – are there spin offs from climate modelling? Have we found out (by accident perhaps) anything useful from them?

      • The Quantum Mechanics analogy is adept.

        You can not predict the path of a single photon in the dual slit experiment, but you can predict the emergence of a diffraction pattern.

      • And the final outcome of all that $100 billion is the climate models. Everything else is just part of the ‘scaffolding’ to that goes into the construction of those models.

        I’m now wondering what your understanding is of what climate models are, how they are built and how they work. Your characterisation simply doesn’t make sense to me – in many ways climate models are the starting point for research into the climate system.

        Climate models are built using quite simple (or in some cases, not quite so simple) rules such as the law of gravitation, planck function, ideal gas law, pressure gradients etc. More recent models incorporate atmospheric chemistry e.g. methane oxidising to CO2. The large scale complexity that emerges from these rules is due to the amount of different objects/forces which are interacting according to them.

        I was listening to a Feynmann lecture the other day and he was talking about a particular theorem related to Quantum Mechanics which had been known for about twenty years but never tested (this was in the 60s). The mathematics described by this theorem when applied to a real situation became so complicated that, at the time, the theoretical consequences couldn’t be calculated. Without an ability to model the consequences of a theory it can’t be tested. This is what climate models, GCMs in particular, offer – the ability to explore the consequences of physical laws that we think are having an effect on climatic systems so that they can be compared with observations. For example, if you ran a GCM without simulating the rotation of the planet there would be a huge difference in weather and climatic patterns.

        Where modelled consequences clearly don’t match observations the differences can be used to explore what’s missing or not quite right – perhaps the modelled elevation of land in certain areas is not quite right, causing a difference in the flow of wind currents, or maybe the grid resolution of the model is too coarse for certain features to properly resolve.

        Depending on what the problem is found to be the model can be improved or the error in the model can be quantified and taken into account in any analysis involving it.

        And it is apparent that they don’t work very well – if at all – on the stuff we want them to do.

        They seem to do produce a generally good approximation of Earth’s climate. Not sure what you want them to do.

        So, before we write off our $100 billion as just money wasted, I wonder if there are any side benefits of these models that we can point to and say ‘well at least we got ……’

        Firstly, even if it is the case that $100bn has been spent on climate research very little of that would have gone on climate model development. Probably the largest expense in modelling would be purchasing and upkeep of the supercomputers used to run them.

        Regarding the side benefits, well the end game for climate science would be the potential for geoengineering, of our own planet or perhaps another one in the distant future. The various space programs may eventually be able to get us to another planet but the chances of encountering a planet habitable to humans would be greatly improved if we can cause it to be habitable. Along the way climate research has aided in vast improvements to forecasting of weather + El Nino and Monsoons.

      • Latimer Alder

        @paul s

        Thanks, I think I understand – and have always understood – how models are constructed. Many years ago I was briefly involved in similar efforts, so I am not a complete newbie.

        But you misunderstand the ‘we’ that I am using. ‘We’ in this case are the taxpayers. The people who ultimately pay your grants and bills and expenses and all that. And we (in that sense) only really fund climatology because we’d like an answer to the question about whether the climate is really changing in ways that might be detrimental to humanity, if so when will it happen and how much. will it be. And maybe to help to give some ideas about what (if anything) we can/need to do about it.

        We ask you to find this out on our behalf and give you a pot of money, expecting you to come back with the answers.

        And you haven’t.

        Instead you’ve constructed a load of models (do we really need more than 20?) that can’t even tell us about the climate a few years out. They may be extremely intellectually interesting , crafted by the finest minds (though everything I read tells me that they are more thrown together like a heap of junk and that its a miracle if they can be run twice without major realtime surgery becuase the coding and methods are so archaic) and beautiful in their elegance.

        But all those things are irrelevant. The do not do the job we have paid for them to do. They do not fulfil your side of the contract. You have had $100 billion dollars, we have got nothing. They are junk. If you were a commercial organisation you’d be so deep in lawsuits as to be drowning.

        As to your belief that only a small part of the $100 billion went directly on climate modelling, that is about as daft as to say that the cost of going to the Moon was only the cost of the Lunar Module, since that was the only bit that actually got there. All of climatology – satellites, paleo, philosophy, datasets – whatever it may be is spent in the end to support the models..to help you guys ake better models and to answer the questions posed above. Splitting out one particular area of specialisation and saying ‘well we didn’t get all the cash it must be Joe down the hall who did’ is a cop out. It is all money for climatology whatever its precise allocation within the system.

        And your spin offs onto other planets are so far into the future as to be little more than a wishlist. That we can now forecast some weather events better is indeed good news. But could we not have got the same result more quickly and more cheaply by just improving weather forecasting?

        Economic times are harder. Budgets are under pressure. In all government expenditure there is increasing pressure to deliver excellent value for money. This is as true of ‘research’ as it is of welfare or the military or anywhere else in public service.

        Seems to me that you guys have been left alone with your sandpit for far too long developing whatever caught your fancy and have taken your eye off the big picture. We don’t give you all this money to write papers, or to Kill the Deniers or to go to conferences. We give it to you to solve a particular supposed problem. And you haven’t done so.

        Time to start either getting the effort back on the right track or to admit defeat and resin yourselves to the fact that it simply can’t be done. Your choice..but one you will have to make soon.

  15. “Our records for the past 15 years suggest the world has warmed by about 0.051C over that period.”

    I have my doubts that scientists can measure global average temperature to within tenths of a degree at any given time. Does anyone seriously believe that “we” actually know the trend over 15 years to within 5 hundredths of a degree? Seriously?

    When did we develop such precise and reliable instrumentation?

    • GaryM,
      Shhhhh! Pointing out the trivial incredibly dubious nature of what AGW is built on is not fair.

    • Latimer Alder

      I believe the instruments in question are tree rings. And they work by a mystical process called ‘teleconnection’. Somehow they are able to give a precise record of temperatures hundreds of miles from their location.

      The theory of teleconnections has been written up by Drs C. H. Arlatan and S. H. Yster and is often cited in the climatology literature. Usually just after the horoscope page.

  16. Free at last, free at last; thank God Almighty hypothesis III is free at last. We can actually talk about it. We can discuss the math of Tomas Milanovic and the physics of Robert Ellison. The Tsonas paper can now be read and reread as a construct that is an alternative to the trace gas radiative transfer model. Is this really the promised land?
    Now really, I do have some tidbits that I have harbored, wondered about, and seem to fit with the implications of Hypothesis III:
    VS on Bart Verheegen’s blog March 2010 demonstrated that for the time series of 1880 to 2008, temperature fell within natural variation; clarifying for me the falsehood of “unprecedented warming” in the late 20th Century. The other tidbit was an observation: global temperatures responded in a homeostatic way to perturbations by the volcanic eruption of Mt Pinatubo and the El Nino of 1998. Each time the temperature was forced up or down, the global temperatures returned to their previous baseline. Homeostatic mechanisms, as applied to climate change would mean that climate sensitivity is very low: i.e., near zero. Therefore arguments and calculations of climate sensitivity, particularly at the 3.5 C guesstimate of IPCC, didn’t make sense to me. Now the climate scientists, other than the Team of course, can pursuit identifying the precursors of and eventually be able to predicts future abrupt climate changes. Pursuing this line of research is more likely than not to lead to better decade weather and climate changes forecasts. Can we put the jibberjabbing aside for a while and concentrate on some science?

    • I agree that a lot of work has to be done on H III but don’t think it can be done on this blog.

      I think that a wiki should be set up and only invited contributors from many different disciplines use it.

      I rather doubt that any mainstream climate scientist would be a suitable candidate for this wiki. Too much linear/rational thinking to be undone methinks :)

    • the volcanic eruption of Mt Pinatubo and the El Nino of 1998. Each time the temperature was forced up or down, the global temperatures returned to their previous baseline.

      Gravity applied to airborne particulates will do this.

      • Gravity influences El Nino swings?

      • “Gravity influences El Nino swings?”

        Mt. Pinatubo generated particulates which eventually fell to the ground due to gravity.

        I view most skepticism as a lack of understanding.

      • So you are only half correct.

        Which pretty much applies to climate science. The part about CO2 is correct, but the part about positive forcings is yet to be proven correct and the part about it all leading to disaster is most certainly overblown to the point of being science fiction rather than science fact.

      • Web, we view your view as a lack of understanding. Evidence based.

    • What is more fun is that starting in 1998 or 2000 is not longer cherry picking, it is comparative analysis :) woohoo! its got a fancy name and everything!

    • Mt. Pinatubo generated particulates which eventually fell to the ground due to gravity.

      Yes, I think the conceptual error can be described by analogy to the basic laws of motion. The OP is making an assumption that volcanic eruptions apply a force to planetary temperature, which is then free to do as it likes within the reference frame of the planetary climate system and that appears to be causing it to flip back into place.

      The reality is that the volcanic eruption applies a force, through the release of reflective aerosols into the stratosphere, moving the planetary temperature, but then a force of equal magnitude is applied as the aerosols are scrubbed out of the atmosphere. There are no clear homeostatic implications – flipping back into place is simply an expected consequence of the sum of forces.

  17. “Note: hypothesis III is consistent with Sneyers’ arguments re change-point analysis.”

    Fundamentally incorrect.

  18. Chief Hydrologist

    The Times articles – I saw it in The Australian – had temperature graphs that show monthly data. It all peaked in early 1998 as a result of the 1997/98 ENSO dragon-king. A dragon-king – I have said before – is an extreme event associated with a chaotic bifurcation. An extreme ENSO event happened at the 1976/1977 ‘Great Pacific Climate Shift’. So we have a couple of examples in the record that are associated with climate shifts at decadal scales. They are linked to oceanographic and global hydrological shifts that are fundamentally important to human societies and the natural world. Oceanographers and hydrologists have been researching these things for decades. My own journey began in 1990 when I read an article on Flood Dominated and Drought Dominated Regimes in north-east Australia. The article (Erskine, W.D. and Warner, R.F., 1988, Geomorphic effects of alternating flood- and drought- dominated regimes on NSW coastal rivers. In R.F. Warner ed.) was inspired by an observation that rivers changed form in the late 1970’s from a high energy braided form to a low energy meandering form.

    ENSO determines 80% of temperature variability in the tropics (McLean et al, 2009) and 70% globally. So the record is complex to start with. There is decadal variability to ENSO and the Pacific more generally and they are associated with the trends of cooling and warming seen in the 20th century. Here is a graph from which this background variability has been removed.

    http://s1114.photobucket.com/albums/k538/Chief_Hydrologist/?action=view&current=MONOTONIC.gif

    It shows moderate warming of 0.08 degrees C/decade in the 50 years to 2000. One of the things to keep in mind is that the background is considerably more variable than we have seen in the 20th Century. This can be seen in, for instance, the 11,000 ENSO proxy.
    http://s1114.photobucket.com/albums/k538/Chief_Hydrologist/?action=view&current=ENSO11000.gif

    There is complex and dynamic behaviour at all scales – but in one sense it is very simple. It is all about energy – energy in less energy out equals the change in energy stored in Earth’s climate system. The problem is the data – SORCE, CERES and ARGO all start post 2000 – so miss the critical shift around the end of the last century. Here is the RSS plot – if you start from the big La Niña in 2000 there is a temperature rise for the decade. Extra warmth is found in CERES and in the ARGO deep ocean data. The problem still is the shortness of the record and how much useful information it contains about even short term events.

    There is data at ISCCP-FD and at the Earthshine project that shows the 1990 shift. My feeling is that the cloud related shift to a cooling influence will intensify as La Niña increase in intensity and frequency for the next decade or 3.

    http://science.nasa.gov/science-news/science-at-nasa/2002/12apr_earthshine/

    http://www.bbso.njit.edu/Research/EarthShine/

    There are also intriguing suggestions that UV changes (not TSI) at the poles are implicated in mid latitude climate change (Lockwood et al 2010). Could this be the missing factor in little ice age dynamics regardless of whether the Thames freezes?

    Robert I Ellsion

  19. Economic actions over purported climate trends are causing an increasing political/financial row:
    Airline industry split widens over EU carbon ‘tax’ row

    A day after China barred its airlines from complying with what many consider a tax, the head of the International Air Transport Association (IATA) warned that several nations view the EU scheme as an “attack on sovereignty”.

    “Non-European governments see this extra terrestrial tax as an attack on their sovereignty,” International Air Transport Association (IATA) director general Tony Tyler said in a speech to the European Aviation Club.

    • This issue has been canvassed previously. From my memory, several posters from the EU (or maybe England) supported the new EU tax on the basis that it only added about $30 to a trans-Atlantic flight

      I pointed out that this tax covered non-EU land and oceans on long haul flights. I now have an answer on the additional cost to a return Sydney-EU-Sydney flight : about AUD$700 (Qantas flight fares, February 7)

      I should also point out that the Euro is a cot case (and the British pound is closer to this than is comfortable), so AUD$700 is considerable

      I really hope that retaliation occurs. Perhaps we may see the Chinese buying old European castles at knockdown prices and turning them into fried rice outlets :)

      • A per capita “landing tax” of €500 for all EU citizens arriving at Chinese airports might be a good start.

        And this could easily be extended with a €1,000 “departure tax” for those wanting to leave.

        Max

      • And the Chinese have told the EU to go and do one, over this tax.

  20. Not a single reference to Earth Orientation Parameters in the article & comments. Every day it’s looking more & more like no one or almost no one who participates in this forum is serious about understanding natural climate variations. Particularly concerning is the apparently popular notion that hypercomplexity (in the mathematical sense) cannot be simple.

    Regards.

    • Chief Hydrologist

      Ride ’em cowboy. Get’s so the irregularities in the Earth’s rotation is as hard to ride as a bucking bull from the western plains. No wait – that’s the bourbon whiskey. Maybe you should give up drinking. As for hypercomplexity – all we need is good ole Max Ent and a power distribution – gives us a fat head or a fat tail. I just keep getting the 2 mixed up. We don’t need no stinkin’ dynamical complexity, high faluting butterfly talk, bifurcated phase space and a whole lot of city slicker glop about autocorrelation and dragon-kings. A cowboy just needs a fat head (fat tail?) to express the untold viccisitudes of the soul. Dang nat city slickerts will fall for it every time.

      • You have misinterpreted the term hypercomplexity. It is meant in the sense of hypercomplex numbers.

      • Chief Hydrologist

        It’s a shibboleth. What part of mad theory didn’t you understand. What the hell has hypercomplex numbers to do with anything in the real world. Oh for Christs sake. Either say something sensible or amusing.

      • Markus Fitzhenry

        How’s that.

        Now I know where that missing heat went. To the deep pressured depths of the oceans.

        “”The pressure of the atmosphere and bodies of water, has the general effect to render the distribution of heat more uniform. In the ocean and in the lakes, the coldest particles, or rather those whose density is the greatest, are continually tending downwards, and the motion of heat depending on this cause is much more rapid than that which takes place in solid masses in consequence of their connecting power. The mathematical examination of this effect would require exact and numerous observations. These would enable us to understand how this internal motion prevents the internal heat of the globe from becoming sensible in deep waters.

        General Remarks on the Temperature of the Terrestrial Globe and the Planetary Spaces; by Baron Fourier.””

      • Not joking about complex numbers Chief. Quite the contrary. This is one of the most serious problems in the whole climate discussion. Ignorance won’t make it go away, even if the ignorance comes from “experts”.

  21. Tsonis et al. (2007) is little consolation for skeptics. His definition of a major climate shift in 1976 occurred after a lull such as this. However his shifts and lulls have an amplitude of 0.1 degrees, and therefore are washed out in a longer term warming trend. Anyway, according to Tsonis, we would be due for another shift that will increase the temperature rapidly.

    • Chief Hydrologist

      I linked to a graph of Tsonis ‘washing out’ the natural variability in the 20th century – http://s1114.photobucket.com/albums/k538/Chief_Hydrologist/ – the residual is about 0.08 degrees C/decade and I am a little tired of repeating myself for people who are psychologically unable to process this fact.

      There are 2 relevant papers – amongst a plethora of excellent work.

      A new dynamical mechanism for major climate shifts
      Anastasios A. Tsonis, Kyle Swanson, and Sergey Kravtsov

      Has the climate recently shifted?
      Kyle L. Swanson and Anastasios A. Tsonis

      ‘This suggests that the climate system may well have shifted again, with a consequent break in the global mean temperature trend from the post 1976/77 warming to a new period (indeterminate length) of roughly constant global mean temperature.’

      The periods last 20 to 40 years in the proxy record – and I don’t think that the 20th Century is an adequate handle on the limits of natural variable. You’re a cowboy that get’s dragged kickin’ and scremin to the dance Jim.

      Robert I Ellison
      Chief Hydrologist

  22. Big news on the USA Today website.

    http://www.usatoday.com/weather/climate/story/2012-02-07/warm-january-climate-report/52999508/1

    The really big news? Nary a mention of global warming or climate change.

  23. Sunday Times: So, Do We Freeze Or Fry?

    why has it warmed so much less than was predicted by the climate models?

    Here are the data:

    IPCC Climate Model Prediction => http://bit.ly/zA0a2j

    HADCRUT3 Observation => http://bit.ly/w2dh2R

    Comparison of model with observation => http://bit.ly/wVWllY

    Here is the discussion regarding the above question in the climate emails:


    1) … to argue that the observed global mean temperature anomalies of the past decade falsifies the model projections of global mean temperature change, as contrarians have been fond of claiming, is clearly wrong. but that doesn’t mean we can explain exactly what’s going on.

    2) Here are some of the issues as I see them: Saying it is natural variability is not an explanation. What are the physical processes? Where did the heat go? We know there is a build up of ocean heat prior to El Nino, and a discharge (and sfc T warming) during late stages of El Nino, but is the observing system sufficient to track it? Quite aside from the changes in the ocean, we know there are major changes in the storm tracks and teleconnections with ENSO, and there is a LOT more rain on land during La Nina (more drought in El Nino), so how does the albedo change overall (changes in cloud)? At the very least the extra rain on land means a lot more heat goes into evaporation rather than raising temperatures, and so that keeps land temps down: and should generate cloud. But the resulting evaporative cooling means the heat goes into atmosphere and should be radiated to space: so we should be able to track it with CERES data. The CERES data are unfortunately wonting and so too are the cloud data. The ocean data are also lacking although some of that may be related to the ocean current changes and burying heat at depth where it is not picked up.

    3) we can easily account for the observed surface cooling in terms of the natural variability seen in the CMIP3 ensemble (i.e. the observed cold dip falls well within it). So in that sense, we can “explain” it. But this raises the interesting question, is there something going on here w/ the energy & radiation budget which is inconsistent with the modes of internal variability that leads to similar temporary cooling periods within the models.

    http://foia2011.org/index.php?id=198

    JC, thanks for the link to the excellent Sunday Times article.

  24. II. Multi-decadal oscillations plus trend hypothesis: 20th century climate variability/change is explained by the large multidecadal oscillations (e.g NAO, PDO, AMO) with a superimposed trend of external forcing (AGW warming). The implications for temperature change in the 21st century is relatively constant temperatures for the next several decades, or possible cooling associated with solar. Challenges: separating forced from unforced changes in the observed time series, lack of predictability of the multidecadal oscillations.

    Based on the data, the oscillation is predictable for the whole temperature record as shown:

    http://bit.ly/Aei4Nd

    1880 to 1910 => Cooling

    1910 to 1940 => Warming

    1940 to 1970 => Cooling

    1970 to 2000 => Warming

    2000 to 2030 [?] => Cooling

  25. Heh. One of the jibes of warmists about skeptics is that they appeal to utter unpredictability and chaos and uncertainty to dismiss all “scientific consensus” re climate. Now, backs to the wall, it is that same “unpredictability” to which they now must have recourse to justify the utter lack of scientific “falsification testing” validation of their Great Cause.

    If the Foo Bird Sh**s …

    • I don’t know what exactly is chaotic about the oceans sinking a significant portion of the excess heat due to the energy imbalance.

      I and II are the same and III is a huge cop-out.

      • WHT

        I and II are not quite “the same”, but they are also not mutually exclusive, i.e. they can be combined: (let’s say 25 parts I and 75 parts II).

        Even III can be combined into a I and II combination.

        And we have no notion how these three theories interact or whether or not there isn’t a fourth one out there, lurking as a “black swan” we cannot even see.

        That’s why myopically concentrating only on anthropogenic greenhouse forcing is so silly – but, what the hell, it has been IPCC’s charter and raison d’être from its inception.

        Max

      • Chief Hydrologist

        Yeah – whet’s so freakin’ complex about the coupled atmosphere/ocean system?

        This is getting funnier by the day.

      • The only way that the earth can exchange energy with the external system is through radiative energy transfer.

      • Web said,”There only way that the earth can exchange energy with the external system is through radiative energy transfer.”

        Very true. You are looking into the diffusion rate into the deep oceans, at what point does that rate decrease to 80 milliWatts/m^2?

        A doubling of CO2 increases the conductivity of the atmosphere by approximately 80 mW. Small potatoes right?

      • WebHubTelescope: The only way that the earth can exchange energy with the external system is through radiative energy transfer.

        Is there a point to that?

      • Is there a point to that?

        The approach I use in applying physics is to remind myself of the fundamental laws as often as possible. This helps to rule out all sorts of impossible scenarios. The basic law of energy transfer establishes the long-term trend.

      • The long term trend (for the short term of millions of years) is dominated by ice ages. Does that help?

    • Markus Fitzhenry

      “Yeah – whet’s so freakin’ complex about the coupled atmosphere/ocean system?”

      It’s hard to tie wealth redistribution into it.

  26. Girma | February 8, 2012 at 2:00 am | Reply

    Challenges: separating forced from unforced changes in the observed time series, lack of predictability of the multidecadal oscillations.

    I have long consdidered that the “forced/unforced” terminology is suspect. In a complex recursive system, the distinction is rather arbitrary. It’s pretty hard to sustain in the face of the long-range observation that a dominantly CO2 atmosphere in deep pre-history was steadily and gradually turned into rock and hydrocarbons (mostly by life), and is now trickling back into play, at VERY slow relative rates.

  27. typo: “long considered that ….”

  28. “rather we need to bring additional physics and theory (e.g. entropy and the 2nd law) into the simple models ….”

    Theorem: The steady-state dissipation of a thermodynamic system due to an energy flux between two isothermal surfaces equals the maximum rate of work possible for a Carnot engine operating between these same temperatures given the same energy input.

    from which it directly follows that the maximum temperature change possible for a 3.7W/m2 forcing is 1.44K. This is merely a limit, not a solution. Unfortunately, the theorem’s derivation is mathematical, not rhetorical.

    pdq

    • quondam said, “from which it directly follows that the maximum temperature change possible for a 3.7W/m2 forcing is 1.44K. ”

      Yep, A scientist has gotta know his limitations :)

  29. Dr Curry: “I don’t see how this statement by Leake is misleading”

    Jonathan Leake: “The implication was that temperatures would rise steadily, not with 15-year gaps”

    IPCC: “The rise will not be steady because of other factors.”

    • Here’s a reliable 30 year (multi-decadal) satellite record:

      http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_January_2012.png

      So what’s your timeslice ?

      • Ian, how about looking at a time slice of the last 15 years? I calculate from the data (UAH data here for lower troposphere) a linear regression trend of 0.85 C/decade, with a 95% confidence range of 0.023 to 0.147 C/decade. (Simple white noise model calculated with Excel; a more sophisticated model taking autocorrelation into account would give wider error bars.)

        Or the 30 years trend? 0.165 C/decade, with 95% confidence range of 0.144 to 0.187

        So that data suggests that the short term 15 year trend is indeed slower than the longer 30 year trend, though the support of that inference is not particularly strong. It also confirms that the trend is still for warming, whether taken over either 15 or 30 years.

    • Latimer Alder

      @louise

      Headline:

      Global warming is bringing Thermageddon upon us. Models show doom is inevitable. Humankind is releasing deadly carbon dioxide. Ice caps are melting, polar bears drowning. Our children will face a much hotter future. Repent now!

      Small print:

      Subsection 14, para 3, clause 71 (unless amended by the IPCC politburo at their annual congress) in a 2000 page document

      ‘The rise will not be steady because of other factors’

      See the difference? Or do you sell dodgy insurance policies door-to-door?.

  30. Meanwhile James Delingpole reports about a German ex-minister of environment, who also observes that “„Seit 12 Jahren ist die Erd-Erwärmung gestoppt!“

    Which elicited Benny Peiser to remark:

    “Imagine if George Monbiot were suddenly to declare himself a climate sceptic. That’s how massive this story is!”

      • He found hundreds of errors. When he pointed them out, IPCC officials simply brushed them aside. Stunned, he asked himself, “Is this the way they approached the climate assessment reports?”

        Vahrenholt decided to do some digging. His colleague Dr. Lüning also gave him a copy of Andrew Montford’s The Hockey Stick Illusion. He was horrified by the sloppiness and deception he found.

        “Stunned.” “Horrified.” Yes, if you read this book you will be appalled, astounded, dumbfounded, horror-struck, overwhelmed, shocked, etc. at the lies, fraud, deceit, dishonesty, inaccuracy, misrepresentation, etc.

        Well, maybe not “shocked” since that might bring to mind Captain Renault’s “I’m shocked, shocked” in Casablanca

        Someone should write a computer program to crank out reviews in this vein of books and articles critical of climate scientists like Santer, Jones, and Mann, in case that’s not what’s already happening here. The thesaurus offers plenty of good words, and there’s a vast range of suitable phrases, with “should be incarcerated for wasting billions of dollars of taxpayer money” and “the biggest fraud since Piltdown man” barely scratching the surface.

        We’ve been here before, plenty of times by now. Those who regard this sort of thing as a contribution to our deeper understanding of the climate have a way of resolving scientific differences that is rarely practiced in serious scientific circles.

      • Vaughan Pratt: We’ve been here before, plenty of times by now. Those who regard this sort of thing as a contribution to our deeper understanding of the climate have a way of resolving scientific differences that is rarely practiced in serious scientific circles.

        Ah. but those who regard this sort of thing as a contribution to our deeper understanding of climate-related political debate are making a serious point that should not be ignored.

      • @MattStat Ah. but those who regard this sort of thing as a contribution to our deeper understanding of climate-related political debate are making a serious point that should not be ignored.

        Matt, what are you saying here? Apologies in advance if I’ve misunderstood you.

        I will grant you that political debaters should not ignore what to them is a serious point. But how about scientists who don’t feel they have anything to offer the political debate? Are they expected to understand the bitterness of the global warming pill, or explain the consequences of not to taking it?

        Wouldn’t science be better off if those who had never come near making it to the debate team, but who had gotten science grades good enough to get them into a good or even great school, were allowed to continue what they find themselves good or great at, and let those good or great at political debate focus their talents on the climate debate?

        In a fair fight, those who don’t accept AGW could go about proving it false by finding competent gladiators for their side and challenging the other side to match them with their best gladiators. Courts of law are organized around that principle.

        But that’s not how the AGW protesters have been going about it. Instead of issuing a challenge to the other side they’ve created their own kangaroo court by kidnapping those scientists they figured would be most hapless when out of their element, arming them with the same weapons their gladiators were trained on, ridiculing them, and then demanding before a massed crowd of onlookers that they show themselves undeserving of that ridicule.

        The crowd that loved the Roman circus 2000 years ago is just like the crowd today that screams their approval when they see blood drawn in the arena, literally then but figuratively today. It’s like throwing Christians to the lions, with the climate scientists as the Christians and the faux scientists as the lions. Lions may not be competent scientists, but they’re far from dumb animals.

        Today’s crowd can’t see the blood, but they can still smell it, and they love it!

        Matt, would you call this a fair fight?

      • Vaughan Pratt: Matt, what are you saying here? Apologies in advance if I’ve misunderstood you.

        Oops. I think we’re stuck in the mud here. You wrote something indirect, I think, with your Thesaurus reference, and my reply was indirect. Two wrong turns don’t make a right turn.

      • Sorry about that, Matt. For my 2013 New Year’s Resolution I think I’ll resolve to replace every pronominal reference in what I write with its referent — oops, I mean the referent of that reference. ;)

    • Latimer Alder

      ‘For you George, the warm is over’

  31. Vaughan Pratt

    Just to be completely contrarian about recent temperatures, I don’t buy the connection with ocean oscillations since it seems to me they’ve been pretty flat since 1990.

    To quote Mug Wump on the long-running Amazon discussion group Global warming is nothing but a hoax and a scare tactic, “It’s the Sun, stupid” which he repeats ad nauseam.

    We’re just now coming out of an odd-numbered solar cycle, namely 23, and embarking on 24. When exiting the even ones the temperature doesn’t go down much (no idea why, but it seems to be correlated with the magnetic alignment of the solar wind—this phenomenon has been going on at least as long as the 162-year HADCRUT3 record, eight evenly spaced instances). Also the exit from 21 was quite weak. 19 was stronger, but the last exit comparable to 23 was 17, which from 1940 to 1950 went down an impressive 0.2 °C after factoring out all other thermal impacts. In comparison cycle 23 only went down about 0.16 °C, not as strong as cycle 17 but enough to almost exactly cancel the CO2-induced warming, while the ocean oscillations stayed out of the picture as noted above.

    Meanwhile the latter hasn’t gotten any weaker, and adding in the likely rise for cycle 24 should produce an impressive amount of warming during the decade 2010-2020! Also I don’t expect the ocean oscillations to remain flat for much longer, but to start going up after an extremely cool spell in the early 1970s, which will add yet further to the temperature in 2020.

    Just my two cents (three if you count the ocean oscillations). Climate skeptics should feel free to chime in with their customary “expect an impressive amount of cooling during 2010-2020.” Check back here in a decade to see who was right.

    • Chief Hydrologist

      You’re a bug eyed loony bin. The only thing you’ll be checking in a decade in a rehab clinic. If you want to provoke ding bat arguments for your amusement in response to your own deliberately ding bat arguments. You’ve come to the wrong place. This is such as shallow facade that it shows your utter contempt for lessor mortals who don’t share and can’t possibly appreciate your inestimable worth. I think you re a ding bat with pretentions of idiocy. You are not even an idiot – you pretend to be an idiot when in reality you are just a brain fried chimpanzee. You think you can play these games for your amusement and the bamboozlement of the herd. Everyone else is too polite or disinterested in your crapola to call you on it – but I will tell you what a crapulous piece of work you are with no dissembling at all.

      • Chief Hydrologist

        Oh have I got you wrong? You really are that stupid? I don’t think so. You have been playing this stupid game all over the threads. But – hey – sorry if you really are that stupid.

      • Hey Chief,

        Calm down.
        Currently scientist figure all their laws and theories are absolutely correct(even though their models are crashing and burning).
        What I find amazing is that as soon as some scientist come out with a calculation, a model is built around it and it is used instead of our real planets parameters.

        Do you know what 48 degrees latitude is?
        It is actually a very important number!
        This is where velocities and centrifugal force separate as the angle of the planet in rotation is too steep and too slow to pull water south.
        If you were to actually generate an orb and rotate it slowly, while pouring water, the water would always want to go to the poles. Rotate this quickly and water flies off at the equatorial region or anyplace at a 90 degree angle to the axis of rotation.

      • Chief Hydrologist

        It is a hoax guys – he is playing you for fools to draw out all the mad theories around the place. It is a deliberate game to discredit – in his own what passes for mind – the blog.

    • Vaughan,

      I don’t buy into the ocean oscillations as well.
      Now, if you were to say looking at the salt density changes of the ocean…
      They do have an effect on the evaporation and precipitation on a rotational planet that have many different velocities.
      http://www-pord.ucsd.edu/~ltalley/sio219/curryetal_nature2003.pdf

      These theories are all temperature data related which do not include any parameters in motion or with physical changes. Strictly temperature data.
      The models are huge mistakes…here is an example:
      “Scientists say that the planet’s axis has shifted based on their models.”
      Okay, let’s look at this with the actual planet. The core and axis are deep in the planet and is incredibly dense. The crust floats on a magma cushion.
      The actual event is that the crust has shifted and NOT the axis.

      Science has generated many idiocies such as this. From not reviewing science theories as technology changes to 95% of science is still considered as unexplored. Yet no one wants to look at anything which may effect the current consensus and funding generated.

      • incandecentbulb

        It is interesting he would quote Mug Wump – ‘AGW is nothing but a hoax,’ thread on Amazon because that thread in immortalized on Board Reader as more emblematic of censorship.

        For Example, you see on Board Reader–e.g., “As Dr. Pielke, Senior has said, in a period when the oceans are cooling there is no global warming during that period. The oceans have been cooling according to the same methodology that the global warming alarmists would presume to use to elevate their conjecture of man-caused global waming from superstition to …”

        But when you tab on the link to the Amazon thread you see the above post was deleted by Amazon based on complaints from the Amazon community.

      • when the ocean is warm and the arctic is open, it snows more and moves water mass from the oceans and adds ice mass on land and the axis does shift.

      • It is interesting he would quote Mug Wump – ‘AGW is nothing but a hoax,’ thread on Amazon because that thread in immortalized on Board Reader as more emblematic of censorship.

        Was this anything more than some disgruntled commenter complaining at some point on Board Reader that Amazon kept deleting their comments? You portray it as a universally accepted fact, which is news to me. “Emblematic of censorship” is unsupportable libel.

        What amazes (and sometimes even annoys) me about that long-running thread (heading towards 40,000 comments?) is just how few comments Amazon deletes from it. Incandecentbulb, can you name even one climate blog that deletes fewer comments? Do you really believe Climate Etc. deletes fewer objectionable comments than Amazon? (Judith, have you made that comparison?)

        On Tamino’s Open Mind for example I’ve tried posting what I (like almost everyone who posts anywhere) had considered to be detailed and irrefutable scientific facts. This was not to make a nuisance of myself there, mind you—I hadn’t even heard of that blog before—but only to defend myself against attacks on me that had been posted there, that weeks later had been brought to my attention, and that were clearly unsupportable. The moderator apparently mistook me for a “zombie” of the kind Steve Sullivan is allergic to, whose presumed goal in life is to make the lives of AGW alarmists miserable, and deleted what I wrote saying that he “wasn’t going to argue with me” while declining to retract his attacks.

        That Tamino thinks “Open Mind” is an appropriate name for his blog reflects poorly on his understanding of the concept.

        Both sides of the climate debate maintain equally closed-minded blogs, such as WUWT, Greenfyre’s, Bishop Hill, RealClimate, JoNova, ScienceOfDoom, etc. On all these blogs, if you disagree with their basic premises, then no matter how logically consistent the basis for your disagreement there’s an automatic presumption of guilt until proven innocent. While I have less experience with Lucia’s The Blackboard and Tamsin Edwards’ AllModelsAreWrong, they seem better in that regard.

        But I digress. My main point was just to defend Amazon against what seemed to me a particularly unjust criticism. (Disclaimer: through no fault but my own I have no interest, vesting or vested, in any part of Amazon itself.)

    • Vaughan Pratt: Check back here in a decade to see who was right.

      I expect everyone will be doing a lot of checking back.

  32. Color me firmly in Hypothesis II territory, which few seem to have staked out. Well, we will see – it is going to be interesting. The IPCC types are certainly resisting shifting toward this ground, though it would seem a natural shift in the face of future lack of warming (it describes my thinking to some extent). Meanwhile, the chaos guys may yet rule the day – but I’m betting against them. My money’s on flatness for the rest of this decade. Check in with you all in 2020.

    • billc, you are such a rebel :) I was thinking a comparison of II to III would be a good approach. You are still going to end up with a range of about 0.52 to 5.2 by latitude with a mean of about 1.48 C.

      That’s just my estimate of course, I should leave the cipherin’ to the real mathematicians :)

      • Capt and others – in all seriousness, what are the high-level physical phenomena by which the difference between hypothesis II and III would manifest itself?

        Oceanic regime changes leading to large shifts in cloud cover might be a candidate??

      • billc, the way I see it, II is like the old farmer’s almanac. The better the past data and the length of the records are, the better it is for making predictions. III is geared toward determining the changes and the causes of the changes. Both have limits, volcanoes and stuff like that.

        As long as both don’t have the same limits, comparing the two should highlight anomalies, the volcanoes and stuff, to improve the efficiency of each.

        There will never be a perfect solution with either method, but comparison should improve the degree of confidence and point out the more significant unknowns.

      • There will never be a perfect solution with either method

        Oh, such a pessimist… ;)

  33. Judith.

    Atmospheric circulation is an oxymoron to temperature data as it is the movement of our planetary gases.
    Velocities and centrifugal force of our planet has generated a very fascinating phenomenon of circular motion. From the creation of snowflakes to the creation of tornadoes all require circular motion.

  34. I have read the lead into the thread, and most of the comments, and I confess I am unimpressed. It seems to me that there are two vital issues, neither of which seemed to have been looked at.

    The first issue is, has anyone detected a CO2 signal amongst the noise of the temperature/time graph? I have seen no evidence of ANY CO2 signal. If is it there, then where is it?

    The second issue to me is the utility of any hypothesis. The reason for hypotheses is to be able to predict what will happen in the future. This then provides a basis for determining which hypothesis is likely to be correct. So given that there are three hypotheses, what do these predict will happen to global temperatures into the future? Then we can get the future data and compare prediction with actuality.

    It seems to be that the most likely hypothesis is that there is no CO2 signal; increasing CO2 levels have a negligible effect on global temperatures. What we are witnessing is temperature governed by a series of phenomena which affect temperature, most of which we simply dont understand.

  35. incandecentbulb

    The end point is where we are now: a continuous and relentless increase in the government-education complex has lead to a runaway power grab and war on the productive.

  36. incandecentbulb

    Every movement and way of thinking and acting that takes on enough gravity to be named will ultimately be analyzed based on ‘trends, change points & hypotheses’ but only after-the-fact by dispassionate chroniclers of the past. We can only guess about the future but my guess is that years from now AGW theory will be seen as the Chevy Volt of science.

  37. Vaughan Pratt


    Check back here in a decade to see who was right.

    How about having a bet with me?

    I say the current global mean temperature record for 1998 for hadcrut3 will not be exceeded in the next three years (2012, 2013 & 2014).

    • wtf.

      that’s not very daring.

      I say the current global mean temperature record for 1998 for UAH will not be exceeded before 2020.

      why UAH? because HadCrut3 is not going to be updated. it’s moved to #4 or whatever. It may be adjusted upwards and get a closer match to GISS. Spencer has indicated a small downward adjustment for very recent temps in the new version of UAH to come soon.

    • I’m young.

      Since it seems unlikely that here in the US we are going to change much in the way of policy, AGW or not, for quite a while, I can wait until 2020 or beyond.

      Sure I’ll take on shorter term bets (in quatloos of course) but they are less important. I guess it’s like all the little races that happen before the Derby, versus betting on the Derby itself, not that I’ve ever been.

    • Chief Hydrologist

      Girma,

      This post and many other from Pratt is simply a hoax. It is something he made up for his own amusement at the simple minded bloggers who respond.

      Do you want to give im the satisfaction?

      CH

    • Vaughan Pratt

      @Girma How about having a bet with me?

      Although I’m not into online betting, Girma, I don’t mind competing with you in the climate futures market based on our respective forecasting skills.

      However I don’t understand why you would want to bet me with on this question. Are you very confident you would win the bet, or do you have some other reason?

  38. A question for hypothesis IIIers,

    External forcing (AGW, solar) will have more or less impact on trends depending on the regime, but how external forcing materializes in terms of surface temperature in the context of spatiotemporal chaos is not known.

    How is that statement reconciled with the trend of significant warming over the entire 20th century?

    • With a prolonged cooling regime, negative PDO, AMO and reduced solar, small, long term, impacts increase in relative significance. Conductive cooling for example decreases less that radiant forcing since one is a 4th power function and the other is nearly linear. The conductive impact may only be 1/20 of the radiant, but over 20 times the period, it balances the radiant reduction.

      It is the total energy transfer over each time scale that is the issue.

      • How is that statement reconciled with the trend of significant warming over the entire 20th century?

      • Joshua, CO2 increased in the last 100 years rapidly with respect to the multi-century feed backs. The longer term, multi-century feed backs are trying to catch up. If we can continue producing more CO2 at the same rate, the the 20Century trend would hold for the next century, with the same natural variation imposed on the trend, Girma’s plots.

        Problems are, the starting point for the last century, was that at the natural variation mean? At what point are we really on the CO2 forcing Curve? And what longer term natural variables of significance exist?

        If the 1900 to 2000 mean is the true global temperature average, then there has been about 0.4 C of warming per century or 0.04 C per decade. That does not sound as frightening as 0.2 C per decade does it?

      • cap’n –

        That does not sound as frightening as 0.2 C per decade does it?

        That is a separate issue. Don’t let your partisan focus drive your analysis.

        The longer term, multi-century feed backs are trying to catch up.

        When I think of something “trying to catch up” I think of a person trying to make a convincing argument or my dog trying to get me to take her for a walk (as she’s doing right now, in fact).

        I have a harder time understanding how multi-century feedbacks can “try” to do anything.

        Problems are, the starting point for the last century, was that at the natural variation mean?

        Even if the impact of ACO2 is stronger than the most concerned predict, i human impact on the environment will not affect the mean temperature of the planet for a very, very, very long time. The mean will most significantly be determined by the temperature of the planet for billions of years prior to human existence.

        What I’m trying to understand with some level of specificity (I know it’s tough to be specific without going over my head) is how Hypothesis III is reconciled against longer-term temperature of temperature increase over the 20th century.

        If you prefer comments from those who are scientifically literate, I’ll quote from Steve’s comment below:

        But even if correct it does not mean that the long term underlying trend is not forcing dependent.

      • sorry….”…longer term trend of temperature increase over the 20th century…”

      • Joshua, there is nothing partisan about that comment. 0.2 C is a worst case, 0.04 is a best case, the range is likely between the two without some unexpected event.

        “Catching up” is a fact of life in a dynamic system. When you hit the brakes on your car, you have to allow for stopping distance that changes with your velocity, road conditions, tire conditions and whether the girl on the side of the road is cute or not :) (reaction time).

        Using the car for another analogy, if you start it once a week, it starts, if your ignore it for a month, it may start, ignore it for a year and you need a mechanic, ignore it for 5 years and you really need a mechanic. Entropy is a bitch!

        Tsonis said that the CO2 signal is super imposed on a longer term trend, which is correct. There is an impact due to CO2. There is also an impact due to agriculture, development, deforestation, black carbon etc. I have no clue how must if due to each, but some, agriculture, seem to have improved conditions and some, development seem to have made things worse. I just want a better feel for the impact of each before I decide the best place to spend the money. Right now, it looks like dealing with black carbon and land use provide the bigger bangs for the buck.

      • cap’n –

        0.2 C is a worst case, 0.04 is a best case, the range is likely between the two without some unexpected event.

        Except if “the CO2 signal is super imposed on a longer term trend,” and we can’t really determine what is causing that longer term trend (and thus can’t determine at what point that imposition of the ACO2 signal will be swamped by long term trends), and we have growth in ACO2 emissions, wouldn’t we expect that the magnitude of the impact of the ACO2 signal will increase?

        In the long run, we’ll all be dead. Looking at long term trends, (say, over billions of years), the signal of ACO2 would, I imagine, not be detectable. That doesn’t really speak to the importance of short term trends to people who live lives orders of magnitude shorter than billions of years.

        Anyway, I’ll read over your responses again and see if I can manage to understand the hypothesis.

      • What is the actual mean is a big deal,

        http://redneckphysics.blogspot.com/2012/02/fruit-cocktail.html

        That is a comparison of the Central England Temperature to Siberian tree rings in the Taymyr peninsular. There is a new study out suggesting that the Little Ice Age was caused by tropical volcanoes. England is influenced by the Gulf stream current, so it is a fairly decent indication of ocean heat content, not great, but not too bad. The Taymyr tree rings are a fairly good indication of growing conditions near the Arctic. The only time that both seem to jibe, is after 1814 or so.

        http://redneckphysics.blogspot.com/2012/01/history-of-modern-agriculture-and.html

        The industrial revolution was the birth of the Agricultural revolution. Lots of land was cleared for wheat following the inventions of the steel plow and wheat combine. Right now, 1% of the total surface of the Earth is planted in Wheat, Rice and Corn, the big three grain crops. A doubling of CO2 will cause about a 1% change in forcing.

        Do you think it is possible that agricultural land use could be responsible for 50% of the warming since 1814?

    • What trends? Post hoc data fitting will not be much help if the data observations are the result of non ergodic influences and cannot be used for prediction.

      External forcings can only be measured and recorded and checks made to detect anomalies in the temperature and other data sets which may result from these forcings.

      Given that the 20th century is a relatively small segment of the temporal continuum of Earth’s climate over the past 2-3 million years, how significant indeed is the warming trend that you assert?

      • Peter –

        Given that the 20th century is a relatively small segment of the temporal continuum of Earth’s climate over the past 2-3 million years, how significant indeed is the warming trend that you assert?

        See my comment above to cap’n.

        http://judithcurry.com/2012/02/07/trends-change-points-hypotheses/#comment-166854

        In the context of 2-3 million years, it is obviously completely insignificant in a mathematical sense. But that doesn’t mean that it is completely insignificant w/r/t the impact of climate in how people live their lives.

        BTW – why limit yourself to 2-3 million years? Why not consider billions of years?

      • Why not consider billions of years? I was really thinking of the period when humans evolved but complex life forms certainly existed much earlier. The paleological (sp?) evidence also indicates that the Earth was much warmer than it is today and of course, much colder at times as well.

        This seems to support the hypothesis that there are strong negative feedback at work in keeping the Earth’s climate within certain bounds conducive to maintaining life. This could just be an accident but many believe that it is not.

    • John Costigane

      Joshua,

      A better question is :

      Can all the warming, cooling phases in the 20th Century, be explained by ENSO?

      A possible answer is:

      The varying number, and intensity, in each sequence of El Nino and la Nina events could be the explanation.

      • John –

        Can all the warming, cooling phases in the 20th Century, be explained by ENSO?

        Wouldn’t that still leave the question of what would explain the longer-term trend over the entire century?

      • John Costigane

        Joshua,

        I understand your question, but you are assuming co2 is the answer. Better to be objective in questions about science.

        co2 is possibly part of the answer. I hope Tamsin can bring some light to the controversy, noting that ENSO is part of some climate models.

      • John –

        I understand your question, but you are assuming co2 is the answer.

        Actually, that’s not quite accurate. I think that within a range of probabilities, ACO2 might be an answer. As I understand it, the “consensus” opinion is based on quantified probabilities of that theory of cause-and-effect.

        Now I can understand why you, as an individual, might think I’m making assumptions that I’m not making. But when it happens in an often repeated pattern in these pages, I have to question why that happens.

        I would imagine that there is some combination of factors in play – but considering probabilities, I’d have to guess that one of them, at least sometimes, is a willful intent on the part of some “skeptics” to impose certainty onto statements I make that don’t express certainty. I see it happen often when some “skeptics” misrepresent the “certainty” of the “consensus” perspective on AGW. You know, the whole “They said that the ‘science is settled’ kind of meme.”

        Again – I’m not saying that I put you into that category. I’m just wondering why a mistaken assumption on your part (about what I assume) is something I find so frequently.

      • Joshua I don’t think it’s willful, I think people project onto you from others perceived to be on your team like Robert, Andrew Adams etc. Heck on Collide-a-scape you told Michael Tobis you were on his team. Liar ;)

      • billc –

        I think that maybe sometimes it happens because I set people up (so I can nail them on making false assumptions).

        But either way, it doesn’t reflect very well on “skeptics” as a group. Either they are suckers easily set up by someone of inferior intelligence, or they are prone to false generalizations rooted in inattention to detail.

        Tobis is on my tribe in some ways, and not in other ways. Kind of depends on how you define tribe.

        And of course, there’s always the “I wouldn’t want to be a member of any group that would have me as a member” line of thinking.

      • Naw you’re much more of a humanitarian than Tobis, snarky as you may be.

      • Latimer Alder

        @joshua

        If you want to keep talking about yourself and analysing people’s reactions to you, I believe that there are plenty of practitioners called ‘therapists’, ‘shrinks’ or ‘loony doctors’.

        But they normally charge a fee for their consultations. I don’t believe that this blog is the right place to come instead for free advice.

        The clue is in the title.It is ‘Climate Etc;, not ‘Joshua Etc.’

      • Latimer –

        If you want to keep talking about yourself and analysing people’s reactions to you,…

        When people consistently make incorrect assumptions about what I assume, I comment on it. I think that the pattern is instructive. When people address comments to me about my assumptions or motivations – as you have done in the post above, I respond.

        Here’s a little logic question for you. If you think that I shouldn’t be responding to comments that people address to me, what is the single most effective thing that you can do in response?

        Ponder that a bit and get back to me with an answer. I’ll tell you if you’re right.

      • @joshy

        When the subject is yourself, I can only rarely be arsed to reply. It does not sufficiently engage my interest.

        The polite word for ‘shrink’ is psychotherapist. I’m sure Yellow Pages will have a section for your community. Or perhaps ‘advanced psychotherapists’ would be more appropriate for serious disorders.

      • Latimer –

        Your response proves that you failed the quiz.

        But don’t let that get in the way of insulting me. Don hasn’t been around much lately, and I miss his brand of comments.

      • @jos….

        Zzzzzzz……….

    • Joshua, a single century only represents 5% of the last two millennia. Relax, then take a deep breath. Don’t forget to exhale now. Feeling better? Good.

    • John Costigane

      Joshua,

      I explained that ENSO could have caused all the ups and downs, including the peak of 1998, which answers your ‘biased’ question.

      • John –

        My question is whether ENSO (or other short-term variables) could explain all the (individual) ups and downs and still not explain the longer-term trend.

    • John Costigane

      Joshua,

      Could the last upslope, before the levelling-off, be unique? That is an unknowable at present, since our knowledge of natural variability is incomplete.

    • Reconciling
      “but how external forcing materializes in terms of surface temperature in the context of spatiotemporal chaos is not known.”

      Point is, that it may not be known or knowable

  39. Steve Milesworthy

    “High frequency ‘noise'” plus uncertainty in the data can plausibly account for the dip around 1910 and the bump around 1940. Even if it only accounts for a small part of these two “features” (say 0.2C for 4-5 years) the perceived excessive “warming 1910-1940” and “the flat trend between mid 1940′s and mid 1970′s” look far less significant.

    And “explaining the flat trend for the past 15 years” is easier because the trend isn’t flat and the period is very short.

    Hypothesis 3 is currently at the level of numerology. But even if correct it does not mean that the long term underlying trend is not forcing dependent.

    • The problem with talking about recent trends i.e. the 20th century without putting them in the context of the warming coming out of the Little Ice Age e.g. http://www.scirp.org/journal/PaperInformation.aspx?paperID=3217 is to attribute the results of a long term trend to short term variations such as 1970 -2000. What we are discussing is the power of CO2 to overwhelm all other factors. The power of CO2 is suggested to be an homogenizing influence. IF CO2 is the overarching factor, than any variation will have little and diminishing impact over time. Longish periods where temperature does not follow the CO2 curve call CO2’s influence into question. That is what is essentially being argued. You may spin as many hypotheses as you wish to explain it, but the result of the data is to suggest that the power i.e. climate sensitivity to CO2 is less than proposed by many. Perhaps a more interesting question that attacks the heart of the question of homogeneity is the large and grown divergence between temperatures in the Northern Hemisphere and the Southern. http://www.woodfortrees.org/plot/hadcrut3vnh/from:1970/to:2011/plot/hadcrut3vsh/from:1970/to:2011 interesting that we see this divergence accelerating 1990 to 2011 http://www.woodfortrees.org/plot/hadcrut3vnh/from:1990/to:2011/trend/plot/hadcrut3vsh/from:1990/to:2011/trend and since 2000 the southern line goes negative http://www.woodfortrees.org/plot/hadcrut3vnh/from:2000/to:2011/trend/plot/hadcrut3vsh/from:2000/to:2011/trend . What is going on. Do the models not assume that CO2 is a global phenomena. Where is the imposed homogenization. This seems to be an even greater blow than the failure of the global temperature to follow the models trend lines projected from the warming from 1970 to 1998.

    • Vaughan Pratt

      “High frequency ‘noise’” plus uncertainty in the data can plausibly account for the dip around 1910 and the bump around 1940

      Is that really specific enough to qualify as an “account?” How do you get such precise dates out of such vague priors?

      The dates of the solar cycles are very precisely known, allowing dates like these to be obtained with at least an order of magnitude better accuracy.

      The declines after the odd-numbered solar cycles 13, 15, and 17 were all strong. Furthermore the bottom of the first of these, in 1908, was within 5 years of the deepest trough of the ocean oscillations since 1850, which was in 1913, which is why 1910 was so cold. And the highest peak of the ocean oscillations during the same 162 years was in 1938, a mere 25 years later, and three years after that, 1941, saw the hottest peak of the solar cycles in that period, namely number 17 (number 13 having been the second hottest back in 1899), whence the 1940 bump. (Note that I’m treating the so-called “ocean oscillations” as a single organic whole rather than as independent AMO, PDO, etc.)

      The second hottest ocean peak was 1877, which in conjunction with the fairly hot solar cycle number 11 peak accounts for the high temperatures around 1880.

      There is less to long term global climate than meets the eye, in fact it is disturbingly simple given our collective prejudices about the complexity of the climate. As one of the students pointed out at our weekly lunch meeting today, this is not so surprising when you consider that the global behavior of the Sun’s output is very simple by comparison with the very complex local behavior of individual sunspots. Climate is not just an incomprehensible muddle, it a mix of simple big things and complicated little things, kind of like Gulliver strapped to the ground with lots of Lilliputians climbing over him.

      Regrettably I can’t say that shorter term phenomena like ENSO are simple: they’re well beyond my ken, and I’m happy for now to agree with anyone who wants to claim they’re complex. However I don’t see them as having any significant influence on phenomena of duration much more than a decade, and I therefore discount them as having little relevance to long term climate forecasts.

      • Steve Milesworthy

        Attention has been drawn by Judith to three “features” of the temperature record without any formal assessment of whether the features are real or are just a figment of the mind being drawn to two cherries – one at around 1910 and another at around 1940.

        These features are being attributed to some sort of non-specific “regime change” that forces climate into a different state.

        But two of the features are accentuated only by two short-term periods of what could be “high frequency ‘noise'” which is apparently explainable by “Hypothesis I” – i.e. a short term period when some of the “natural” cooling or warming influences converge.

        If you look at datasets with different coverage (eg. Land only, northern or southern hemisphere only, US only) then these “features” look very different suggesting that they would be sensitive to changes in coverage of the datasets.

        None of this, though, takes anything away from ongoing warming driven by ongoing increases in forcing as Hypothesis 3 is only concerned with shifts away from the longer term forced trend. It doesn’t displace “AGW theory”.

      • Latimer Alder

        @steve milesworthy

        Talk me through the argument once again, please:

        Problem:

        We have two periods off apparent warming 1910-1940 and 1970-2000 They have about the same slope and are of about the same length. They are both pronounced enough to be considered a trend.

        You then say that the first ‘could be attributed to short term periods of high frequency noise’, but are adamant that the second is due to some other cause (I guess CO2 emissions).

        Maybe Occam’s Razor is no longer fashionable, but when you have two very similar phenomena occurring within the same system. isn’t it a wise idea to have as your starting point the idea that they are the same thing happening twice? (I fully accept that your investigation may in fact show them to be different, but such examples will be the exception rather than the rule).

        Because it seems to me that to really demonstrate a proper understanding of climate you have to be able to explain both periods with exactly the same rigour and within a comprehensive theory.

        You can’t really say …’We’ve done oodles of work on the recent stuff and have totally convinced ourselves that the only possible cause is CO2′ and then just dismiss the earlier period as ‘could be high frequency noise’. It will not take an Hercule Poirot to smell a rat and to conclude that your homework really hasn’t been done, nor your comprehensive (Its all down to CO2, stupid) theory submitted to any sort of real test.

        So please explain once more how you come to two very different conclusions about the two periods in question. You may also recall that – as a one-time chemist – I just love to see experimental evidence rather than vague generalised hand-waving.

        Thanks.

      • Steve Milesworthy

        Latimer,

        The 1910 to 1940 warming was preceded by 0.2C of cooling and followed by 0.2C of cooling.

        Therefore, if the 1910 minimum were high frequency Hypothesis 1 cooling applied to a warmer background and the 1940 peak were high frequency warming on a cooler background then what you are left with is almost monotonic (forced?) warming from 1890 to 2011.

        Pre-war temperature also has the potential for being noisier because the sampling covered less of the globe so is more prone to confluences situations where they drive cooling/warming in the observed locations and the opposite in the non-observed locations (cf the difference between HadCRUT3 and GISTEMP).

        Post-war we simply have an ongoing trend of warming that is slower at the start of the period, then is fast in the 1980s and 1990s and is then slower – that’s 60 years.

        The two periods are not the same because the second period is longer, has a warmer base-line, is better observed and appears more consistently and more clearly in, say, the land-only data. So a naive application of Occam doesn’t seem appropriate.

        Of the two interpretations I prefer mine as being less speculative than assuming a “climate shift” of no known cause. And, again, the climate shift idea does not deal with the longer term warming trend.

      • …then these “features” look very different suggesting that they would be sensitive to changes in coverage of the datasets.

        Or sensitive to something else. Like urban stations growing (warming), then moving to rural airports (looks like a cooling), and then build-up around the airports over time (another warming).

        Here’s an example:

        Trend is 2.0C/century at the city station, but only 0.1C/century at the airport, which is moderated by the flat temperatures until the mid 1970s.

      • @steve m

        Thanks for the more detailed explanation.

        But your discussion of the 1910-1940 period still relies on two ‘if’s, with no supporting evidence, a general assertion about observational techniques a while back and then on your own preference for your explanation compared with any other.

        Fair enough, and you are, of course, entitled to your opinion just as anybody else is. But it’s not what I would call a rigorous proof. It is a plausible hypothesis, but unless I have missed an essential point it is no more than that.

        And this is deeply worrying.. For we are told that the explanation of the more recent period of warming has been unequivocally shown to be primarily caused by the increase in CO2 concentration in the atmosphere. And from this proof follow all sorts of other scientific, political and economic consequences.

        I also opined that to show that the climate is really well understood, you need to be able to demonstrate that you have a numerically based explanation of both periods of warming that use the same conceptual model.

        But if the best explanation you can advance for Period 1 is so woolly and vague, how much can we be certain of the answer for Period 2? Surely it should be almost trivially simple. You take the model you have for Period 2 – the unequivocal one with all the bits about CO2, just rewind it back to 1910 and lo! if the model is right, out pops the curve for 1910-1940 and the cooling after that ..and so on.

        This is not difficult to do and the ‘correct’ answer would be powerful and persuasive evidence that you really have got a theory that effectively covers periods when CO2 could not be a strong influence. By implication it would also mean that your understanding of all the other possible influences would be pretty much on track.

        This is so obvious a thing to do that I am pretty bemused as to why it doesn’t seem to have occurred to anyone. You have all the tools and techniques, all the equipment, all the staff, all the expertise..and a success in that demonstration would ineed be a triumph for you theory.

        So why not? What is holding you back? Or is it one of those pieces of work that never get published for fear of ridicule? That maybe somebody somewhere did try it but couldn’t get the required answers? And rather than risk the wrath of the elders decided that the best thing was just to stay schtumm?

        As ever, value your views…..

      • Steve Milesworthy

        Latimer,

        Of course there are two perhaps unresolvable “ifs”. We cannot go back in time to see in more detail what happened in 1910 and 1940.

        However, we cannot therefore attribute it to regime change either.

        My point is, really, that the “ifs” are not in the slightest bit implausible. As Chris Ho-Stuart has pointed out below the divergences between the various temperature datasets in the past decade or so are as large as the divergence in the SST dataset that would be required to explain the two features that have given rise to the apparently similar length warming trend of 1910-1940.

        Until there is better evidence for “regime change” then theory 1 seems sufficient to me. I think Occam would agree.

        Evidence required for H3 would be what? A prediction of a change in some as yet unobserved feature of the climate? Observation (I use that word casually) of regime change events in high-end climate model simulations?

      • Latimer Alder

        @steve m

        (In haste as I have to go out to work tonight, brrrrr).

        I made a suggestion as to exactly how you could resolve the issue in a way that potentially gives you a win-win triumph for your theory. Easy enough to do and you have all the resources available. If you can run a model fro 1980-2000, you ought to be able to run it for 1910-1940…and, if it is any good, you will be able to show good agreement with the old observations. If not……..

        But if, for some reason unfathomable to those of us who pay the bills for your organisation you find yourselves unable to do so, then yours is just one explanation among a multitude of others.

        I do not think it is implausible.. indeed I’d probably lay a bob or two that may be at least partly on the right lines. But the point I have been labouring to make is that having a plausible explanation only gets you to the starting line. It does not get you onto the podium. To do that requires a lot more work.

        Thinking back to my university viva days and the terrifying array of gowns and professorships there arrayed, I could just imagine the dialogue:

        Difficult examiner #1; Mr Alder, we understand that you have a theory about climate. Please describe it to us
        LA: Well sir I have done a lot of work on period 1980-200 and I can conclusively show to my satisfaction that its all due to the evil gas carbon dioxide. There are lots and lots of computer programmes that demonstrate this
        DE#2: Indeed. We shall want to look at the very carefully. No doubt they are available to public scrutiny?
        LA: Mostly sir
        DE#3: Turning now to the similar period between 1910 and 1940 for comaprison…what caused that warmign according to your programmes?
        LA: Please sir I don’t know sir. I’ve never tried them.
        DE#1: Why not, young man?
        LA: Never occurred to me sir but its all down to the noises isn’t it? Anyway it was a ded long time ago and nobody cares
        DE#2: not very scientific Mr Alder, We will adjourn to consider our verdict

        (sorry gotta go…maybe more later)

      • Steve Milesworthy

        Latimer,

        Such model runs have already been done and are reported in the IPCC report. But they don’t help with short term variability because the natural variability of even two identical planets would cause temperatures to diverge.

    • Latimer Alder

      @steve milesworthy

      Is just ‘being plausible’ a high enough standard of proof? Because I’m sure that we could all come up with plausible explanations. Surely science – and especially experimentation – is the technique we have learnt to use to distinguish between explanations that are merely plausible and those that are actually true.

      Have you any better evidence than ‘plausibility’?

      • Steve, Latimer is making a similar argument to mine. You talk about “plausibility,” but without a concrete definition of “high” in “high frequency” and a concrete algorithm for converting priors into posteriors, the dates of highs and lows you point to are just handwaving based on direct observation of those lows and not an inference from correlated observations.

        Certainly one can say an observation is self-explanatory, for example the rising of the Sun each morning. However it is not customary to consider self-explanation as scientific explanation. For the latter one tends to look for a non-vacuous and quantifiable correlation with observations of other phenomena. Correlation with high frequency is non-vacuous but you haven’t quantified it.

    • The link to the image didn’t show in my previous comment. Here’s one more try:
      http://imageshack.us/photo/my-images/338/abileneraw1.gif/

  40. NOAA data clearly shows that when earth is warm, it snows more. More snow stops warming, every time. Look at the data for the past ten thousand years. Every warm period is followed by a cool period.

  41. The implication was that temperatures would rise steadily, not with 15-year gaps. The existence of such gaps, the critics argue, implies the climate models themselves are too flawed to be relied on.”

    It always snows more when the oceans are warm and the arctic is open.
    They don’t have this in their models correctly.

  42. I’m surprised that Judith raises the question of whether or not global warming has stopped with presenting a graph like this.

    http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif

    I’m not a climate scientist but I think I can recognise a peak when I see one. And this the temperature in this graph hasn’t peaked! Certainly I’d be very happy if my share investment graph looked like this too!

    PS haven’t we had this conversation before?

    • Sorry. Should be “without presenting a graph like this”

    • May not have peaked, but looks like a small plateau to me. Whether this is the summit or not remains to be seen. But there sure hasn’t been any pronounced upward trend in the last few years.

      Which raises the interesting question of what happened to
      a. cause the warming period of 1910-1940 and
      b. stop it.

      Because without bomb proof numeric explanations of those events – using exactly the same theories as are used to explain today’s events – it is clear that we do not have a solid understanding of climate, however much those professionally involved would wish us to believe that they have.

      • Vaughan Pratt

        I fully agree with Latimer on all these points.

      • I agree also. A trend does have to be a change in sign, just a change in slope does nicely.

        Funny about the 1910-1940 period. I brought that up on realclimate some time ago. I was not particularly impressed with the answer. Seems you can cherry pick solar reconstructions that show a couple tenths of degree warming but not for a couple of tenths of a degree cooling. Lean 2000 for warming, 2008 for no warming. Picking which one applies seems a bit complicated to me.

        Of course, climate science is a developing field. Polar amplification actually means mono-polar amplification. Climate science though, is definitely bi-polar :)

    • PS haven’t we had this conversation before?

      Heh.

      By what % would blog comments decrease if everyone was restricted to not repeating conversations?

      • Just think of all the money the nation would save. Free, for nothink.

      • Latimer’s response is the best so far to your initial question Joshua. I was going to try to respond but since I declared my support for Hypothesis II (HII, etc. cause I’m tired of typing that word) I didn’t. However thinking about Captain’s response to my initial comment I realize that I think HIII is informative and don’t wish to dismiss it except to restate my expectation that the chaotic change points will not be dominant.

        Joshua I think you should rephrase, because the problem with significant waming over the 20th century is the mid-century rise and fall, such that even the IPCC does not attribute early century warming to ACO2.

        I do think that over the long term, ACO2 will increase its influence. But I am skeptical that we have proof of its significance yet. It seems likely that coming decades will show less warming than 1970-2000, IMO. The smoking gun for at least SOME contribution from CO2 is the magnitude of the 1970-2000 warming and our understanding of the relative strengths of forcings to date.

        I do allow for the possibility that chaos-based shifts will alter this picture. What I don’t have is the mathematical understanding to use this in any way, and it seems to me even the most math-literate here (eg Tomas Milanovic) don’t profess to be able to use it to make predictions.

        I do hope someone can help me understand what I referred to earlier as “high level physical manifestations” of these chaotic shifts. Again, ocean regime changes affecting cloudiness and therefore albedo, seem the most obvious, but I imagine there are others.

      • You cannot change a person’s mind by just telling them something one time. You must tell them more than once and point them toward data that supports your position. This still don’t work if they don’t read and think.

      • Boy, you can say that again.

    • The arctic is open, the snows have started and temperature is at or near the peak. Earth is about as warm as it usually gets in a modern warm period.
      http://popesclimatetheory.com/page27.html

    • gistemp…(snicker), gistemp…(guffaw), gistemp…(LOL), gistemp…(ROFLMAO)

      sorry, I tried but I just can’t say it with a straight face.

  43. Hi Judy- Excellent summary of this issue. I also agree hypothesis III is the most likely. In our paper

    Rial, J., R.A. Pielke Sr., M. Beniston, M. Claussen, J. Canadell, P. Cox, H. Held, N. de Noblet-Ducoudre, R. Prinn, J. Reynolds, and J.D. Salas, 2004: Nonlinearities, feedbacks and critical thresholds within the Earth’s climate system. Climatic Change, 65, 11-38.

    we wrote

    “The Earth’s climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual,…It is imperative that the Earth’s climate system research community embraces this nonlinear paradigm if we are to move forward in
    the assessment of the human influence on climate..”

    David Douglass is a leader on this subject, and I look forward to his next paper that will illuminate this issue further.

    • This is a really poor explanation for the extremely stable temperature cycle that has dominated for ten thousand years.
      Actually, it is no explanation at all.

      • Chief Hydrologist

        ‘Large, abrupt climate changes have affected hemispheric to global regions repeatedly, as shown by numerous paleoclimate records (Broecker, 1995, 1997). Changes of up to 16°C and a factor of 2 in precipitation have occurred in some places in periods as short as decades to years (Alley and Clark, 1999; Lang et al., 1999). ‘
        http://www.nap.edu/openbook.php?record_id=10136&page=10

        The explanation for abrupt change in the last 10,000 years is that they hve been smaller and less persistent than paleoclimatic abrupt change. BUt they are there – and they are evident even within the extreme limitations of the instrument record.

        You have but to open your eyes to see.

        Robert I Ellison
        Chief Hydrologist

      • Vaughan Pratt

        You have but to open your eyes to see.

        Chief, I closed my eyes and right away I could see what you meant. ;)

        The first epigram here bears on this, as does Circa Survive here:

      • Chief Hydrologist

        I don’t know Vaughan old buddy – I quote the NAS and you link to a blogger called Chairman Pratt. There is bit of a pointless asymetry here.

        Robert I Ellison
        Chief Hydrologist

      • I was expecting the title of the song, “Close your eyes to see”, to pop up but it didn’t, you have to click on the “watch on YouTube” button to see it.

    • @rpielke
      “It is imperative that the Earth’s climate system research community embraces this nonlinear paradigm if we are to move forward in
      the assessment of the human influence on climate..”

      Take out anything to do with human influence and I agree 100%. Human influence may well be a factor but a more holistic approach should be taken with respect to climate research.

      There is a strong need to better understand the underlying physics of the Earth systems in play and top explore the many dynamic relationships that the available data may show.

      • Peter said, “There is a strong need to better understand the underlying physics of the Earth systems in play and top explore the many dynamic relationships that the available data may show.”

        It is a touch wishful to model the impact of a 0.028% change in a mixed gas composition when you are not all that sure what the other 99.972% does. Course, that might just be a little simple minded on my part.

      • Vaughan Pratt

        Take out anything to do with human influence

        What do you mean by “take it out?” Do you mean that we should only study natural influences on climate and ignore anything humans might be doing?

      • VP..to clarify… To take out “human influence” I was merely referring to Roger’s sentence, so thus I could agree 100% with the sentence. Not to eliminate it altogether from further study! It certainly is a factor to be examined but not to the exclusion of numerous other (more important, IMO) factors.

      • Thanks for clarifying that, Peter.

        (FWIW, IMO the human one is more important, but I’m well aware that’s a distinctly minority view on this blog.)

        @cd: It is a touch wishful to model the impact of a 0.028% change in a mixed gas composition when you are not all that sure what the other 99.972% does.

        As far as trapping IR goes, which is the concern about CO2, we have an extremely accurate idea of what the other 99.972% does, thanks to the comprehensive HITRAN line spectra tables and our understanding of the current rates of growth of all the surface-temperature-relevant gases.

        But you knew that, so perhaps you had some other point in mind that I’ve overlooked.

  44. I. IPCC AGW hypothesis:
    This one will be proven wrong in the next decade(s). Since the annual atmospheric CO2 growth will decrease with the cooling, consensus will be forced to rethink the “all of the CO2 increase is caused by anthropogenic emissions” hypothesis. If the decadal average for 2010s is lower than the 2000s average (~2 ppm/year), the paradigm will have to shift. I assume the BAU emissions scenario. I predict lower than 1.5 ppm/year decadal average for the 2010s.

    Independently from the CO2 attribution, global cooling will disagree with the CO2GW hypothesis and the “climate sensitivity estimates”. Zero or infinitesifal or even negative is not ruled out. Not to forget nonsensical.

    II. Multi-decadal oscillations plus trend hypothesis:
    This is a bit undefined and fuzzy. I disagree with:
    – the large multidecadal oscillations (e.g NAO, PDO, AMO) being unforced. There is some good evidence of the oscillations correlating with solar oscillations. Some of it may be system response, but it can’t be separated at this point.
    – the trend is linear and unchanging. The trend itself is another oscillation.

    III: Climate shifts hypothesis:
    I don’t really understand this one.

    My hypothesis:
    Most of the global climatic change is caused by solar oscillations. These are coupled with orbital oscillations (solar, Earth’s and other planets’). We know too little of the mechanisms and modulations of energy transfer between Earth and space (solar system mainly). We can NOT calculate the balance. It would be like taking the Drake equation seriously. Meanwhile, we can recognise the basic patterns and maybe even predict (multi)-decadal global climate changes.

    • I predict lower than 1.5 ppm/year decadal average for the 2010s.

      Ok, but now let’s use the CDIAC historical data for the past few decades for all anthropogenic CO2 contributions to the atmosphere (mainly fossil fuel consumption, flaring, cement, and land use), to work out how different the 2010s would look from the past five decades if your prediction came true.

      Since 1958 the steady rise in atmospheric CO2 comes very close to an equally steady 40% of what the CDIAC says the total human emissions of CO2 come to.

      You didn’t say anything about emissions decreasing, so let’s assume business as usual for emissions. If those don’t depart significantly from the curve, then at the 40% rate the CAGR (average annual increase in atmospheric CO2) between 2010 and 2020 will be 2.6% per year. (Currently it’s 2.35% and by 2020 it will be 2.9%.)

      For your forecast of a decrease from an average of 2.6% to an average of 1.5% to come true, that 40% rate is going to have to drop to 40*1.5/2.6 = 23%.

      That is, you’re predicting that the 40% rate of retention of our emissions, which has remained very steady since we started measuring atmospheric CO2 carefully in 1958, will within the space of a single decade drop to 23%.

      Do you see the problem?

  45. AR4 was published in 2007 but can anyone identify when the prediction of .2º/decade was inserted into the document? That insertion date starts the clock, not the publish date.

    • Vaughan Pratt

      Are you thinking of 0.2 ºC/decade as any of unreasonably low, or unreasonably high, or about right?

      The last 18 years of the annualized BEST data, starting shortly after Pinatubo, show a steady increase of 0.362 ºC/decade that doesn’t contain any obvious indication of letting up. (Note that this is not over a mere decade but rather over Santer’s proposed minimum of 17 years.)

      Of course the BEST data didn’t appear until 2011, and it’s for land (which is where over 99% of humans live so it’s more relevant to us than sea temperature), but if it’s at all reliable it would appear to be showing that 0.2 ºC/decade is way too low by nearly a factor of two!

      Anyone who thinks it couldn’t possibly be increasing at 0.36 ºC/decade should be screaming bloody murder about the BEST data being totally fraudulent. Right? ;)

      • Vaughan Pratt

        (Sorry, I meant last 17 years, not 18 — 1993-2010 means Jan. 1993 to Jan. 2010 in Paul Clark’s WoodForTrees system.)

  46. Journal of Climate, Feb 2012, Surface Water Vapour & Temperature Trends, (Isaac & van Vijngaarden, York University, Toronto)

    Conclusion:

    A reduction in relative humidity can occur even though water vapor pressure is increasing if temperature is warming sufficiently. Hence, decreases in relative humidity occur at stations experiencing the largest temperature increases in winter and spring as shown in Fig. 7. The strong correlation between increasing temperature and decreasing relative humidity trends agrees with that found by Vincent (Vincent et al; 2007)

    Oooooops, so tell me again, how many GCMs have physics which match with the observed reduction in relative humidity with rise temperature and the consequent negative water vapour feedback?

    • dude I don’t think the observed reduction in relative humidity with rising temperature implies a negative water vapor feedback, just a less strongly positive water vapor feedback than has been otherwise postulated.

  47. “By what % would blog comments decrease if everyone was restricted to not repeating conversations?”

    Hah! And yet one might as well ask, by what percent would *all* human conversation decrease if no repetition were allowed?

  48. ceteris non paribus

    I think this linear vs. nonlinear change distinction is perhaps a false dilemma.

    It’s rather like the theory of ‘punctuated equilibria’ in evolutionary biology. The fossil record shows periods of relative stasis punctuated by periods of relatively rapid change. Some have taken this fact to undermine the theory of natural selection. But it is all a question of scale. When you look closely at the periods of rapid change, they too are commensurate with natural selection. The theory relies upon ordinary speciation, and thus the morphology proposed is a form of evolutionary gradualism, in spite of the name.

    Do we need a new non-linear paradigm of the climate?

    I don’t know the answer to that question, but I am curious as to what such a paradigm would even look like.

    For example – How could the climate paradigm change without a fundamental change in our understanding of the relevant physics? That won’t happen just because we ‘decide’ to adopt a new paradigm – It would require convincing evidence that our current physical theories are false. There is a huge difference between false and uncertain.

    • i still keep thinking the place to start is explaining how it might affect the cloud response. the absolute magnitude of that is so large. maybe i should keep on banging this drum. i’m sure CH think’s he’s answered it but us dummies can’t figure out what he’s really saying.

      • Chief Hydrologist

        This is what the new paradigm looks like – http://www.nap.edu/openbook.php?record_id=10136&page=12

        At the top of atmosphere it is all very simple. Energy in less energy out equals the change in enery stored in the Earth system over any period.

        In the maelstrom of the planet things change abruptly from one state to another very much like any deterministically chaotic system in electrical circuits to ecologies, economics, populations and climate models.

        ‘AOS models are members of the broader class of deterministic chaotic dynamical systems, which provides several expectations about their properties (Fig. 1). In the context of weather prediction, the generic property of sensitive dependence is well understood (4, 5). For a particular model, small differences in initial state (indistinguishable within the sampling uncertainty for atmospheric measurements) amplify with time at an exponential rate until saturating at a magnitude comparable to the range of intrinsic variability.’
        http://www.pnas.org/content/104/21/8709.full Warning – this paper is a very hard slog.

        http://s1114.photobucket.com/albums/k538/Chief_Hydrologist/?action=view&current=sensitivedependence.gif

        What is important is what changes in the energy dynamic – and clouds are a big part of this in the short term. Largely because – I think – of changing sea surface temperature both in the Pacific and Atlantic. It makes sense to me that clouds form over cold seas and dissipate over warm. The observations at both the surface and from satellites seem to support that – see some references here for instance – http://judithcurry.com/2011/02/09/decadal-variability-of-clouds/

        As a concept – climate is a single global system with tremendous energies cascading though powerful systems. It comprises hydrosphere, atmosphere, cryosphere, ecosphere, heliosphere and pedosphere. The reductionist error is to consider parts in isolation. The new paradigm is to consider the whole as a complex dynamical system. How that is done is another question – but the fact that it is difficult doesn’t matter to God or the universe.

      • ceteris non paribus

        That’s CH’s problem, not ours. Burden of proof.

        Never assume that you are a dummy just because someone else fails to make any sense to you. There is a second possibility to consider.

        I think it’s very interesting that we are now considering the possibility of rapid “episodic and abrupt” climate change, and yet we are constantly and confidently told that climate sensitivity is low.

        It can be difficult to keep up – The climate times, they are a-changin’! :-)

      • Chief Hydrologist

        Cet – old Buddy – you want it both ways do you? Not that there is anything wrong with that – it explains the identity crisis at least.

        Chaotic systems are extremely sensitive in the region of a bifurcation but insensitive elsewhere. A small push tips the system over into a new state entirely – so rising temperature could for instance push the system into abrupt cooling in as little as a decade.

        ‘Most of the studies and debates on potential climate change have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. But recent and rapidly advancing evidence demonstrates that Earth’s climate repeatedly has shifted dramatically and in time spans as short as a decade. And abrupt climate change may be more likely in the future.’
        http://www.whoi.edu/page.do?pid=12455

        But will the politics ever survive random cooling over 30 years? No one will ever believe it again. And there will be you and me on our own – Cet old buddy – and the Woods Hole Oceanographic Institution – saying but wait climate is hypersensitve in the region of a chaotic bifurucation. What’s not to understand? I guess lonesome is just part of the iconic nature of being a cowboy.

      • Ceteris said:

        “I think it’s very interesting that we are now considering the possibility of rapid “episodic and abrupt” climate change, and yet we are constantly and confidently told that climate sensitivity is low.”

        Agree that this is the big gotcha to all the “natural variation” skeptical views. They want to ascribe changing temperatures to internal stimulation, which however implies a very touchiness or sensitivity to the strength of the stimulation. The more sensitive the climate, the less internal stimulus is needed to get it to adjust.

        Now take that sensitivity to external radiative forcing. That same sensitivity is still there, but now it is responding to the external stimulus instead of an internal source. I mentioned this in a top-level post to this blog a couple of months ago.
        http://judithcurry.com/2011/11/29/wht-on-schmittner-et-al-on-climate-sensitivity/
        The physical analogy is doing a random walk in a shallow energy well. If the climate doesn’t have a steep well wall, it can wander.

        All that Hypothesis III is a cop-out, and the term “chaotic attractor” at its root is a fancy euphemism for an energy well.

      • Chief Hydrologist

        Some of it is fast response – http://www.osdpd.noaa.gov/data/sst/anomaly/2012/anomnight.2.6.2012.gif – the big blue V in the eastern and central Pacific in a La Nina and warm water in the same vast expanse in an El Nino.

        Some of it is slow response – http://isccp.giss.nasa.gov/zFD/an9090_SWup_toa.gif – cloud feedbacks from the shifting ocean temperatures.

        Can’t figure out what I’m saying? It’s a shibboleth. Dont know what it means either but it feels good just to say it.

      • Chief Hydrologist

        I was moseying along in a random walk in a shallow well and hurt my ponies nose. Thanks Webby.

    • How could the climate paradigm change without a fundamental change in our understanding of the relevant physics?

      http://www.engineeringtoolbox.com/laminar-transitional-turbulent-flow-d_577.html

      To improve the heat transfer between fluid boundaries you can increase the turbulent flow, which increases both the molecular contact rate and the rate of diffusion in the fluid. Simple right?

      ENSO is a product of changing turbulent flow rates between the ocean and the atmosphere. The ENSO is defined as the change in temperature for a few boxes in the Pacific ocean. There are a bunch of boxes and a bunch of ocean. All you have to do is figure out the thermal impact of the change in relative velocities for each and every box, then you have a fair start.

      Then there is the long term laminar flow puzzle. Heat exchanged in the polar regions cools the sea water to approximately 4 degrees C. That water sinks in a slow more viscous flow exchanging very little heat producing a thermal boundary in the deep oceans. The rate of thermal diffusion into and out of that layer is extremely slow. Once you have the turbulent flow problem solved, jump on the laminar flow problem.

      It should be a piece of cake to solve the transitional flow problems. Oh wait? I think there is a prize of some kind to solve that problem.

      Let’s see, convection in the atmosphere can be laminar, transitional and/or turbulent, it must impact the radiant transfer as well, since there is horizontal convection which can be laminar, transitional and/or turbulent. That horizontal convection can be below, at or above the average radiant boundary layer.

      I am sure a simple up/down model can figure out all that is going on.

      So there is nothing new about non-linear issues in fluid dynamics, it is still a difficult problem. Climate science has yet to scratch the surface.

  49. Speaking of trends, see:
    Surface Water Vapor Pressure and Temperature Trends in North America during 1948-2010, Journal of Climate 2012 ; e-View
    doi: http://dx.doi.org/10.1175/JCLI-D-11-00003.1
    V. Isaac and W. A. van Wijngaarden

    Over 1/4 billion hourly values of temperature and relative humidity observed at 309 stations located across North America during 1948-2010 were studied. The water vapor pressure was determined and seasonal averages were computed. Data were first examined for inhomogeneities using a statistical test to determine whether the data was fit better to a straight line or a straight line plus an abrupt step which may arise from changes in instruments and/or procedure. Trends were then found for data not having discontinuities. Statistically significant warming trends affecting the Midwestern U.S., Canadian prairies and the western Arctic are evident in winter and to a lesser extent in spring while statistically significant increases in water vapor pressure occur primarily in summer for some stations in the eastern half of the U.S. The temperature (water vapor pressure) trends averaged over all stations were 0.30 (0.07), 0.24 (0.06), 0.13 (0.11), 0.11 (0.07) C/decade (hPa/decade) in the winter, spring, summer and autumn seasons, respectively. The averages of these seasonal trends are 0.20 C/decade and 0.07 hPa/decade which correspond to a specific humidity increase of 0.04 g/kg per decade and a relative humidity reduction of 0.5%/decade.

    Support for the saturated greenhouse effect leaves the likelihood of AGW tipping points in the cold

    • There are several interesting theories and I read many comments from posters who have “studied the climate” and “deeply understand” various aspects of the climate and are quite sure what drives the climate and the relative importance of CO2.

      Simple question– does anyone’s theory or relative understanding really matter until they can demonstrate it is accurate by having it modeled and then showing that the model matches observations over a reasonable period? Longer periods of matching observed conditions will lead to higher confidence in future predictions being accurate.

      Trusting models that do not match observed conditions is called faith. (that something will change in the future to make them accurate)

      • Vaughan Pratt

        I agree 100% with Rob on this point. It’s amazing the faith people put in inaccurate models.

    • Bottom line is that humidity increased. Relative humidity is not the absolute humidity.

    • WebHubTelescope
      Bottom line is that the SURFACE specific humidity increased while the relative humidity decreased.
      That says nothing about the upper atmosphere.
      The historic radiosonde data showed more strongly declining upper atmosphere specific humidity vs increasing lower atmosphere specific humidity. e.g. Paltridge et al. Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data

      It is accepted that radiosonde-derived humidity data must be treated with great caution, particularly at altitudes above the 500 hPa pressure level. With that caveat, the face-value 35-year trend in zonal-average annual-average specific humidity q is significantly negative at all altitudes above 850 hPa (roughly the top of the convective boundary layer) in the tropics and southern midlatitudes and at altitudes above 600 hPa in the northern midlatitudes. It is significantly positive below 850 hPa in all three zones, as might be expected in a mixed layer with rising temperatures over a moist surface.

      There are a number of global warming objections that the data must be wrong attributing differences to slow sensor response etc.

  50. Apropos to trends, change points, and hypotheses:

    http://www.yaleclimatemediaforum.org/2012/02/jpls-josh-willis-looks-ahead-to-continuing-sea-level-rise/

    The combination of the video and the exchange in the comments is quite interesting, IMO.

    • when the arctic is open, much of that water falls as snow and becomes long term ice.
      when the arctic is open the sea level falls, it don’t rise again until earth cools and the snow stops falling.

    • interestingly, and as discussed in some of the comments on the page you link to, it appears the trend in SLR is slowing, even if you try to avoid cherry picking by truncating the curve in 2010. Just by a little. It’s been discussed before. It’s interesting to think of what the combination of a flattening in SLR and simultaneously land-atmosphere GW might mean. Maybe nothing. Maybe the missing water is in space!

  51. People worry about one molecule of manmade CO2 per ten thousand molecules of other stuff, including the three molecules of natural CO2.
    An asteroid hit the earth and killed the dinosaurs and other species, changed the orbit and spin axis and earth survived. We have caused some changes, but our changes are tiny compared to natural changes.

    • Latimer Alder

      @HAP

      But Carbon Dioxide is The Death Gas!!!

      Too much CO2 will cause the planet to be overrun with those dreadful plant things growing everywhere. Which is not at all what we mean by ‘going green’ :-)

      • The day of the Triffids was a portent. Give them too grow-juice and the blighters will try to take over.

        The Green Peril Looms,
        We’re Doomed, we’re doomed
        We’re DOOMED! :)

  52. The furniture on the deck of the Titanic needs to be re-examined in detail, plans carefully made and redone, and rearranged again and again until we get this furniture finally right once and for all. But then again we shall have to rearrange it because my salary depends on this furniture!

    “It is difficult to get a man to understand something, when his salary depends upon his not understanding it!” – Upton Sinclair

  53. sorry to be off topic – looks like a number of Book reviews are in for Michael Mann’s new book..

    Scot Mandia’s is worth a perusal (laugh)
    http://www.amazon.com/gp/cdp/member-reviews/A1U43LM86A5W5P/ref=cm_cr_pr_auth_rev/192-3584096-0290965?ie=UTF8&sort_by=MostRecentReview

    like Peter he didn’t apparently like Donn’as book much..
    I notice John Cook and Dana have also given 5* reviews …

    • Barry –

      Your link didn’t get me to a Scot Mandia review of Michael Mann’s new book (for which I might be grateful). My Amazon link throws up two reviews – neither which is by Dana or John Crook!

      Am I looking in the wrong place?

  54. Climate models are very complicated. There are sections of code from many different disciplines. No one of them understands all the disciplines. Whoever puts this all together does not understand all the different disciplines. No one in the different disciplines understands how this all works together. Since all the disciplines had an input, they all accept the output as absolute truth. This is the Gospel of Climate Science.

    • Vaughan Pratt

      Climate models are very complicated.

      Ok, I understand the complaint. But if someone came up with a simple and accurate model would your objection to climate models then be that they’re too simplistic?

  55. I liked this quote from the Sneyers abstract:

    it seems justified to conclude that there are severe limits to climate predictability at all scales

    I think anyone who has an interest in following the weather could have told you that. Which maybe explains why so many meterologists seem to have doubts about the threat of climate change.

    • Vaughan Pratt

      I think anyone who has an interest in following the weather could have told you that.

      Not unless you have a different definition of weather from Mark Twain: “Climate is what you expect. Weather is what you get.”

      There do indeed appear to be severe limits to climate predicability at all weather-relevant scales. But how does that extend to all scales? How would you go about showing that we have no hope of predicting the global temperature averaged over the period 2075-2100 to within say a degree?

      • Chief Hydrologist

        There are 2 answers to that – hombre – and they both involve model ‘plausibility’.

        ‘AOS models are therefore to be judged by their degree of plausibility, not whether they are correct or best. This perspective extends to the component discrete algorithms, parameterizations, and coupling breadth: There are better or worse choices (some seemingly satisfactory for their purpose or others needing repair) but not correct or best ones. The bases for judging are a priori formulation, representing the relevant natural processes and choosing the discrete algorithms, and a posteriori solution behavior.’ Irreducible imprecision in atmospheric and oceanic simulations – James McWilliams

        The first plausibility criteria requires billions of dollars and thousands of times more computing power.

        ‘The global coupled atmosphere–ocean–land–cryosphere system exhibits a wide range of physical and dynamical phenomena with associated physical, biological, and chemical feedbacks that collectively result in a continuum of temporal and spatial variability. The traditional boundaries between weather and climate are, therefore, somewhat artificial.’ A UNIFIED MODELING APPROACH TO CLIMATE SYSTEM PREDICTION
        by James Hurrell, Gerald A. Meehl, Davi d Bader, Thomas L. Delworth , Ben Kirtman, and Bruce Wielicki

        The second plausibility criteria is much simpler to implement.

        ‘Atmospheric and oceanic computational simulation models often successfully depict chaotic space–time patterns, flow phenomena, dynamical balances, and equilibrium distributions that mimic nature. This success is accomplished through necessary but nonunique choices for discrete algorithms, parameterizations, and coupled contributing processes that introduce structural instability into the model. Therefore, we should expect a degree of irreducible imprecision in quantitative correspondences with nature, even with plausibly formulated models and careful calibration (tuning) to several empirical measures. Where precision is an issue (e.g., in a climate forecast), only simulation ensembles made across systematically designed model families allow an estimate of the level of relevant irreducible imprecision.’

        As running simulation ensembles across systematically designed model families would require billions of dollars and thousands times more computing power – we simply decide subjectively what a plausible solution looks like after the fact.

        As for how accurate this is – seriously – who really gives a rat’s arse.

      • Ombre de hombre, wallet be ballot, all of it fall out.
        ===============

      • Chief Hydrologist

        Yee hah – yippee-ki-aye – I’m the climate cowbot.
        Dude – get lost – we want a shiny billion $ superbot,
        Not a lonesome, iconic, laconic, ironic dusty cowbot.
        Shibboleth – it’s just a game I play for fun – it’s just a…

      • Vaughan,

        I think Mr Clemens has basically said the same thing I did – just better expressed.

        And the quote I referenced said ” severe limits”, not impossibilities. I’m not taking the position that modeling is worthless. I do believe that modelling should not be the primary basis for policy, as it isn’t yet good enough to tell us what is happening.

      • I do believe that modelling should not be the primary basis for policy, as it isn’t yet good enough to tell us what is happening.

        Agreed. I further believe that the current approach of modeling the equilibrium states and treating the transitions between them as only of secondary interest is doomed to failure, because for a long time now and for the foreseeable future we’re in a transition with no equilibrium state within a century of today’s date.

      • Chief Hydrologist

        ‘I haven’t lost my temper in 40 years; but, Pilgrim, you caused a lot of trouble this morning; might have got somebody killed; and somebody oughta belt you in the mouth. But I won’t. I won’t. The hell I won’t!’

        The bushwhacking SOB is reduced to making snide comment from the sideline. They are surpringly free of any science at all for one with such a limited capacity for wit.

      • Don’t they give away the game when they use “ensembles” of model runs to get the best fit for hindcasting?

        http://www.pnas.org/content/107/5/1833.full

      • Chief Hydrologist

        ‘The global coupled atmosphere–ocean–land–cryosphere system exhibits a wide range of physical and dynamical phenomena with associated physical, biological, and chemical feedbacks that collectively result in a continuum of temporal and spatial variability. The traditional
        boundaries between weather and climate are, therefore, somewhat artificial.’ A UNIFIED MODELING APPROACH TO CLIMATE
        SYSTEM PREDICTION by James Hurrell, Gerald A. Meehl, Davi d Bader, Thomas L. Delworth , Ben Kirtman, and Bruce Wielicki

        The weather and climate quote is from Heinlein not Twain.

  56. Stephen Wilde

    “Meanwhile, we can recognise the basic patterns and maybe even predict (multi)-decadal global climate changes.”

    Quite so.

    Poleward and/or more zonal jetstreams mean that the troposphere is bit warmer as the rate of energy flow through the troposphere increases.

    Equatorward and/or more meridional jetstreams mean that the troposphere is a bit cooler as the rate pof energy flow through the troposphere declines.

    But either way the total system energy content fails to change because BOTH are NEGATIVE system responses to anything that tries to take the system away from the energy content dictated by atmospheric surface pressure and solar input.

    Add to that the 60 year oceanic cycling and the millennial solar cycling from MWP to LIA to date and that gives a pretty good idea for predictions.

    We currently are going into a cooling oceanic phase for 20 to 30 years but it is a bit early to be at the solar cycle peak though the current solar quietness suggests that possibly the peak arrived early and we are now on the way down. Could still be few active solar cycles to come though.

    Meanwhile the jets are more meridional/equatorward than they were so the troposphere is currently cooling and more clouds from more wavy jets is reducing the amount of solar energy getting into the oceans which will intensify La Nina dominance for so long as the sun stays quiet.

    I suspect that that will turn out to be a better guide to the future than the current GCM output.

    Bookmark this post and review in 5 years.

    • Markus Fitzhenry

      Thanks for that Mr Wilde.
      You’ve given me inspiration to wrote a book for children, titled:

      “How Our Climate Works, Understanding Macroclimatology.”

      Titans, such as yourself, have made it so easy to understand it won’t take me long at all. See you when I’m finished.

      Cheers for now,

      • Markus, is that sarcasm or not ?

        I don’t see any intrinsic problem in boiling a highly complex system down to the fundamentals. Whether it is right or wrong can be readily checked against ongoing events.

      • ‘The Pet Climate’, cartoons by Josh.
        ==========================

      • As Craig Loehle said:

        “One of the ways people deal with too much data/information is to make a simplifying story. A good simplifying story would be Newton’s theory of gravity, which in its simplist form ignores friction and other minor factors”

      • Markus Fitzhenry

        No sarcasm, I meant it is a compliment.

      • Chief Hydrologist

        Did Craig say that? My engineers heart shrivels into dust – and I stand vindicated. Friction is routinely included in the calculations involving the laws of motion. Really – the only thing that is not included in the Newtonian Laws of Motion is relativistic effects – and that is entirely forgivable as – when ambling along the trail on my pony – relativity only really matters when we are being chased by cougars.

        Robert I Ellison
        Chief Hydrologist

      • Chief,

        That’s what the gun is for. The cougars that is.

      • Friction is routinely included in the calculations involving the laws of motion.

        What “laws of motion?” Certainly not Newton’s three laws of motion, which don’t breathe a word about friction.

        Perhaps you’re referring to the laws of motion as taught to hydrologists, where dynamic viscosity, kinematic viscosity, and fluidity are important.

      • Chief Hydrologist

        Don’t worry ‘bout bitin’ off more than you can chew, Pilgrim, cause your mouth is bigger’n you think.

        ‘3.Third law: The mutual forces of action and reaction between two bodies are equal, opposite and collinear.

        Perhaps you didn’t get past the first 2. Seriously – I can’t be bothered instructing you in kinetic or static friction. Is this seriously embarrassing or just your regular horses arse idiocy?

  57. I wonder how many are aware of the policy implications of what is happening.

    If models are not useful in a decadal timescale, such as they can predict a strong warming for a period of minimal or even no warning, then what use is there for models? What government (apart from North Korea…) would make it difficult for people to heat up their homes in the next decade with the explanation that is going to be warm in 2070 anyway?

    People do not average-out their lives across decades or centuries: each and every one of us have to go through each and every day first.

    If I freeze to death today at -10C, I will not enjoy the warmth of July at +30C even if the average is +10C, perfectly compatible with human life. The same can be said of plants and animals. If I plant an olive tree in my London garden, it will die of cold in February even if the yearly average is in theory just enough to make olive trees survive in the open. If a nasty mosquito species migrates from warmer places during an August heatwave, still if that species cannot survive the following winter it will not be around until next migration opportunity during a future heatwave.

    A purely statistical, multi-year approach to modelling the climate is in theory useless for policymaking (similar considerations could be made for non-regional projections, but that is too long a story here – read “How Space-Time Digested AGW” if interested). And if we end up with 15 years of incorrect projections without even a volcano for an excuse, then whatever physical explanation there is, policymakers would be much wiser in keeping climate scientists at arm’s length.

    • Interesting thoughts.

      I largely agree, but would add that there are plenty of other reasons for policymakers to keep climate scientists at arm’s length..

  58. Chris Ho-Stuart | February 8, 2012 at 3:10 am |
    Steven mosher, I don’t see the problem with the graph you mention. It includes a shading envelope that indicates a range of possibles. It has a horizontal scale on which ten years doesn’t even show (the tick marks are 50 years apart).

    To paraphrase E.S…. As you can’t read a simple chart, maybe you should take my Graph lab/class.

    • Urk. You are right… the tick marks are 20 years apart. Mea Culpa.

      I do still think that the ticks marks, along with everything else about the graph, show that it is not attempting to predict 10 year windows of warming.

      But I salute a valid coup!

  59. Let us grant that someone has proposed 3 theories, as in the head post. The standard way to proceed would be to see if any of them could be disproved. IPCC has made no effort to disprove II and III, which have sufficient explication (in my opinion) to be called at least plausible. In fact, when it is pointed out that the GCMs are running hot, it is claimed that “oh no, we said II is possible with decadal fluctuations”–but if that is allowed, how does IPCC know that the warming from 1980 was not itself just (or partially) a natural fluctuation?

    • Fair point.

      But haven’t the IPCC allowed for a large portion of natural variation from 1980 by saying that (only) more than half can be attributed to AGW?

      I only say that because the famed attribution statement strikes me as the one genuinely conservative thing in the whole of AR4.

    • Dikran Marsupial

      This raises an interesting question, which is how should the IPCC (or anybody else for that matter) falsify hypothesis II and III, which although they are at least plausible, make no testable predictions, unlike hypothesis I. Has anybody made projections for future climate with an unambiguous statement of uncertainty that would allow the projections to be falisfied by the observations?

      Hypothesis I also has the advantage that it can be used to make a model based on physics, rather than statistics, that can at least explain past climate. I am not aware of any phsyical model based on hypothesis II and III that can explain 20th Century climate without the enhanced greenhouse effect.

      Another reason that hypothesis II and III are not as plausible in my view is that for them to be correct, our understanding of radiative physics etc., which have been tested experimentally and by observations (e.g. spectra of outbound IR radiation) must be fundamentally wrong. This is possible, but unlikely – scientific revolutions do occurr, but not as frequently as individual scientists just getting things wrong.

  60. To all who still argue the climate models predicted the current global mean temperature pause, here are the predictions from IPCC’s own website:

    Graph => http://bit.ly/zA0a2j

    Text => http://bit.ly/caEC9b

    Comparison of Prediction and observation => http://bit.ly/wVWllY

    • Girma; the point we are making is that climate models DON’T predict the timing of short term (decadal) pauses or accelerations. What model runs show is that the rate of change is not steady on that scale, but that the underlying main trend shows up over a scale long enough to smooth out the unpredictable short term variations up and down.

      Having a slow down over 15 years is in line with what we should expect according to conventional climate science. What conventional science can’t do is predict when slow down or speed up occurs. The graph you show is explicitly for “means”. Reading the report shows that this is the output of an ensemble; not a single model. It does not include and does not try to include short term variation around the trend (which is not predictable); it shows the mean.

      Your “comparison” is apples and oranges. You are comparing a single data line (the observed line) with a mean line. What you SHOULD compare with is a smooth of the data; a moving average, perhaps. The scale of the window should be something from 15 to 20 years. Recent work (discussed here at climate etc in this commentary by Judith: Santer on timescales of temperature trends has been more precise, identifying 17 years as the window over which the trend is showing over the short term variation.

      So to compare like with like, take a 17 year moving window average of the data. You’ll find it’s within the right ball park for the IPCC projections from models.

      • Chris

        I disagree with “the models are okay” claim.

        Here is IPCC’s verifiable statement.

        Since IPCC’s first report in 1990, assessed projections have suggested global average temperature increases between about 0.15°C and 0.3°C per decade for 1990 to 2005. This can now be compared with observed values of about 0.2°C per decade, strengthening confidence in near-term projections

        In the above statement, the IPCC used a 15-year period from 1990 to 2005 for trend calculation.

        Here is the trend for this period from 1990 to 2005 => http://bit.ly/wULkoQ
        This trend is a warming of 0.24 deg C per decade, as stated above.

        Now, let us check the above statement against the trend for the 15-year period from 1995 to 2010.

        Here is the trend for this period from 1995 to 2010 => http://bit.ly/wFhfXH
        This trend is a warming of 0.11 deg C per decade.

        This is outside the range between about 0.15 deg C and 0.3 deg C per decade.

        Chris, does this result weaken or strengthen confidence in the near-term projections?

      • Chris

        Another point is the observations are below the model mean.

        As a result, real climate sensitivity should also be lower than IPCC’s mean value of 3 deg C.

      • The four years leading up to 1995 included a solar max, but the four years leading up to 2010 were in a deep minimum. Do you think that makes a difference, or should we just ignore solar cycles in all this?

      • Girma, the equilibrium climate sensitivity (estimated at about 3C per CO2 doubling; or about 0.8 C per W/m^2) is not related to the rate of increase, but to how far the increase goes until the Earth is back in energy balance. You are again comparing apples and oranges.

    • Nice job! That deserves a smilie :)

  61. Dr. Loehle,
    Precisely.

    If we take the commonly accepted interpretation of the IPCC statements as projecting 0.2 Deg C/decade temperature increase, then over the 15 year period from 1997 it would have been reasonable to expect a 0.3 Deg C increase. Instead, a 0.051 Deg C increase was measured, which could be interpreted to imply (assauming the IPCC argument is correct) a natural negative variation of 0.249 Deg C over the period, or 0.166 Deg C/decade. If it is accepted that a negative natural variation of 0.166 Deg C/decade can occur, surely it is not unreasonable to accept that a 0.166 Deg C positive natural variation could occur from time to time.

    To reach the canonical value of 0.2 Deg C/decade over the canonical 30 year period starting from 1997, it’s clear that temperatures would need to increase by 0.549 Deg C or 0.366 Deg C/decade over the next 15 years. Let’s see.

    (By the way, a 0.2 Deg C/decade increase would imply a temperature increase that would fall within the stated limit of 2 Deg C temperature increase to avoid catastrophic climate change).

    • Instead, a 0.051 Deg C increase was measured

      “Measured” in what sense? One can easily measure a substantial decline by careful choice of endpoints.

      Over the past two years various people have pointed out on the basis of how weather has varied over the past several decades that projections based on less than a decade are unreliable. In Feb. 2010 I proposed 15 years as a minimum, 6 months later Tamino proposed the same number, more recently Santer has proposed 17 years.

      If you go with 17 years you will see 0.36 °C/decade in the recently released BEST land-temperature data from Richard Muller’s group at Berkeley. Furthermore there is no sign of any flattening in that data during the past decade.

      • Vaughan

        With BEST, you are ignoring 75% of the globe.

        Please return to hadcrut and gistemp when discussing trends =>
        http://bit.ly/Aei4Nd

        Do you see any change in the global mean temperature since record begun about 160 years ago?

        Is it not a single pattern of a warming of 0.06 deg C per decade with an oscillation of 0.5 deg C every 30 years? WHY NOT?

      • Chief Hydrologist

        I propose a 100 years – after all we want a really long term trend that encompasses all of the variabilities – see Girma for the details – I really can’t be bothered.

      • Is it not a single pattern of a warming of 0.06 deg C per decade with an oscillation of 0.5 deg C every 30 years? WHY NOT?

        When you include those two offsets of ±2 °C I would have to agree with you.

        If you increase them to ±20 °C it looks so flat that I’m not sure I can see any warming trend at all.

        However if you decrease them to ±0.2 °C then it becomes easier to see differences that aren’t so visible with your suggested ±2 °C. In particular I would say on the basis of that last graph that you are quite right about the rise from the 1st peak to the 3rd peak, but quite wrong about the rise from the 1st peak to the 2nd, which is a lot less than your proposed 0.5 deg C every 30 years, and from the 2nd to the 3rd, which is a lot more.

        This difference is also present in your original graph, and to the same degree, it just isn’t as obvious when you zoom way out like that.

        I’d say on the basis of your original graph, when looked at more closely, that this warming trend is not following the straight line you suggest but is bending upwards. WHY NOT?

      • CH, I propose 162 years. We have the data.

  62. Yes but Vaughan, surely you are aware that choosing a 17 yr period with a start date of 1994 right at the bottom of the Pinatubo cooling effect is a nice big fat sweet juicy red cherry pick:) It is difficult to see any significant long term trend with a series containing extreme weather outliers including Pinatubo and the mother of all El Ninos 98.

    • Agreed

      Here is a reliable 30 year satellite record (starts 1979 because that’s when the sats started operating). Difficult to cherry-pick anything much other than ENSO in that timeslice

      http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_January_2012.png

    • choosing a 17 yr period with a start date of 1994 right at the bottom of the Pinatubo cooling effect is a nice big fat sweet juicy red cherry pick:)

      This would be a fair objection if I had chosen this out of a range of alternatives. However I was trying to make the point that this is what you get when you try to include as much as possible of the allegedly flat 2000-2010 period while still meeting the Santer 17-year criterion. With those two constraints I had no alternative. (One can extend 2010 very slightly to 2010.2, but no further because of the insane outliers in the last two months of the BEST data!)

      But since you think I’m cherry-picking, it would only be fair to let you cherry-pick a 17-year period (or longer if you prefer) from the BEST data that makes the opposite point. Go for it!

      Note that I composed three moving-average filters of widths 12, 10, and 8 months in order to remove all traces of < 12 month high frequency noise. That combination turns out to be an extremely effective filter for that purpose, for reasons that are best explained in terms of side lobes in the frequency domain if anyone's interested. If you don't remove the high frequency noise it becomes easier to cherry pick from among 17-year windows, so to that extent I'm making it as hard for you to cherry-pick as I made it for me. Just didn't want to give either of us an unfair advantage.

  63. I’ve taken the time to download some data and calculate the trends. I’ve used the global temperature data from GISS, NCDC and Hadcrut3. I’ve also taken the lower atmosphere data from UAH, which is closely related. I’ve calculated trends using Excel. The spreadsheet also includes BEST data for comparison. I’ve not quoted results here, since it measures land only, which gives stronger warming trends throughout.

    Here are trends for the most recent 15 years, in C/decade. That is 1997 through 2011 inclusive.
    Hadcrut3: 0.01
    UAH: 0.10
    NCDC: 0.05
    GISS: 0.10

    This is even less warming that Leake mentions. But if take the 15 years to July 2011, I get this:
    Hadcrut3: 0.05
    UAH: 0.11
    NCDC: 0.08
    GISS: 0.12

    That’s a bit closer to numbers in Leake’s article; it’s possible he’s working from numbers he obtained some months before publication. But in general, the 15 year trend is going to vary a fair bit over different time periods. There’s still a lot of influence from short term variation on that scale. This is not some new excuse to explain any failure of predictions; it’s been a stock standard part of climate science for the last twenty years.

    The 95% confidence on these trends is roughly 0.05. That’s using the regression confidence, without any consideration of confidence on the underlying data. A crude confidence guide just to give a ballpark idea. This means that the data does show, with confidence, a short term trend which is less than the longer term trend we’ve seen over recent decades. That’s not particularly surprising, and (conventionally) most scientists expect the stronger long term trend to continue to be apparent over this century at least. If the recent lull persists another ten years, then there might be reason to look askance at conventional expectations. The current data, however, is consistent with conventional expectations.

    It has been suggested that the recent lull over the last 15 years makes it unlikely that the next 5 years will allow for a strong warming trend over 20 years. We’ll see about that in five years time; in the meantime, here are trends for the 20 years just past (1992 through 2011 inclusive). (Regression confidence limits about 0.04)
    Hadcrut3: 0.16
    UAH: 0.21
    NCDC: 0.16
    GISS: 0.21

    Those numbers match the expected trend of about 0.2 C/decade.

    There is no IPCC prediction for the trend over the last 15 years. There IS, on the other hand, an expectation that the main underlying trend is about 0.2 C/decade or so; where “about” can be read as 0.15 to 0.3. It’s well understood and explicit (not explicit enough for everybody it seems, but certainly not a hidden footnote either) that this trend is not expected to show over short windows of time; but only over windows of time long enough to smooth untrended variations.

    Recent work has identified 17 years as a window over which the underlying trend starts to show. (Judith has commented on it also here at Climate Etc: see Santer on timescales of temperature trends)

    There is still a fair bit of up and down seen in the 20 year trend when I look at the data. But any 20 year window from about 1980 to now, in any of those datasets, shows a trend somewhere from 0.15 to 0.25 C/decade. I expect that to continue; just as I expect to continue to see substantially greater and smaller trends over a 15 year window or less.

    I have adapted this comment to be a post at the experimental SkyDragon forum. In that post I include also links for all the data files, for the spreadsheet, and images of plots of how trend varys with time. Basically I plot the trend value for a window centered at a given time, for every possible window of that length. Hence you can see how the 15 year or 20 year trend (or others) varies over time. You can find it at Recent trends in global temperature. If you would like to discuss further, I’ll continue to read both here and in the forum.

    Girma, this also relates to your question. You don’t expect 15 years to show up the long term trend. You do expect to see the long term trend start to dominate over short term untrended variation over longer windows, like 20 years. Those numbers are not an excuse for failed predictions. They are a feature seen in the data. It’s ALWAYS been understood that untrended variations make short windows not much good for looking at a global warming signal; that’s the nature of climate.

    I know you don’t agree with the models. That’s your prerogative. But it is just wrong to say that the recent 15 year lull conflicts with IPCC expectations.

    Cheers — Chris

    • Chris

      This means that the data does show, with confidence, a short term trend which is less than the longer term trend we’ve seen over recent decades.

      Thank you for that.


      That’s not particularly surprising

      I disagree.

      Because of the following:


      Yeah, it wasn’t so much 1998 and all that that I was concerned about, used to dealing with that, but the possibility that we might be going through a longer – 10 year – period of relatively stable temperatures beyond what you might expect from La Nina etc.
      Speculation, but if I see this as a possibility then others might also.

      http://foia2011.org/index.php?id=6226

      • Girma, you show an email in which a conventional climate scientist considers the possibility of a ten year lull. Apparently you take this to mean that lulls are NOT considered possible in the conventional picture. Boggle.

      • Chris

        but the possibility that we might be going through a longer – 10 year – period of relatively stable temperatures beyond what you might expect from La Nina etc.

      • Yes… so? La Nina etc (the major factor in “1998 and all that”) is not the only short term influence, and scientists know this. Such lulls have occurred before. They aren’t a surprise and we are not good at predicting them, and you’re STILL citing a climate scientist who is considering the possibility of a 10 year lull. That’s SUPPORTING my position.

      • Chris, the basic problem is that sensitivity is an abstract concept that has little to do with reality,

        David, let me suggest a different possibility. Like everyone else in the world you have no clue what climate sensitivity is, and therefore have no clue whether it is abstract, concrete, or even meaningful.

        So equally you have no clue as to whether it has anything to do with reality. In your complete ignorance of the concept, for all you and anyone else in the world might know, it might have everything to do with reality.

      • If I may continue the piling on Wojick. He doesn’t seem to realize that abstractions help us understand reality. Just because a concept is abstract does not mean it doesn’t reflect reality.

        “By analogy, abstractly one can throw a potato chip as far as a baseball, but don’t bet on it. In short, the focus on radiative physics is misguided.”

        Again poor Wojick does not understand what the word abstract means. In this case, he probably meant to say hypothetically. Radiative physics is not abstract, as it is clearly the mechanism by which the planet maintains its average temperature. So Wojick is saying that modulation of the radiative transfer leading to temperature change is only a hypothetical premise.

      • WebHu

        uh, you need to look up abstract in the dictionary. (hint: it means not practical, applied or real).

      • (hint: it means not practical, applied or real).

        I’m afraid I have to agree with you here.

        On the one hand that’s merely definition 3 here out of 5 definitions of this adjective.

        On the other, in my reply to David I was assuming it was the one he intended, since I’m not aware of his ever having used that adjective with any of the other four meanings.

        To back up WHT’s point, temperature is a great example of a quality that is concrete to the Man In The Street but abstract to a physicist. So abstract in fact that a molecule can’t run a temperature. A gas cannot have a temperature unless it consists of at least two molecules.

        The MITS reasons that one molecule moving at ten times the average speed of air molecules at sea level must be much hotter than average, but this only shows a lack of appreciation for how something like temperature becomes meaningless without an abstraction on which to base it.

    • The 30-year linear trend for 1990 – 2020 will be 0 (+0.1/-0.1).

      • Wow. Forget cycles; you’re proposing the 30 year warming trend will fall off a cliff in the next few years! To get that would be spectacular.

        Last time there was a 30 year trend as low as 0.1 was around 1960-1990.

        I think about 0.15 to 0.2 should be in the ballpark.

      • Chris, shoudn’t it be 0.6 °C (3 x 0.2 per decade), according to IPCC?

      • Your post was talking about the “linear trend”. So was I. The IPCC suggested “about 0.2” for the linear trend. I’m going slightly on the low end of that, for a linear trend of 0.15 to 0.2 C/decade.

        You know that trend is not the same thing as “difference between two end points”? It’s not even the difference between end points divided by time difference. That varies a lot more than the trend.

      • at .15C you become a lukewarmer.

      • Edim, the 50 years trends in Hadcrut3 are positive over every 50 years you pick last century. Although it does get very close to zero in the middle.

        1900-1949 inclusive has a trend of +0.100

        It goes up to a local high of +0.102 over 1903-1952; this is actually the culmination of a steady increase going into the previous century.

        It then declines fairly steadily to a minimum of +0.003 over 1930-1979

        Amazing. What a coincidence. That’s the 50 years you picked out!

        It then increases again, to a maximum of +0.141 over the most recent 50 years.

        This is consistent with the physical factors driving climate that we know of. The major factors in the early part of the century appear to be a mix, coming out of the little ice age. The middle decline is mostly (we think) from anthropogenic aerosol pollution. Enhanced greenhouse has been a factor all along, but that really took off from around 1970 or so, and is now easily the dominant forcing. The 50 year trend will, I expect, continue to increase, as it sheds the tail of that mid century cooling window.

        The physical expectation is that the trend will continue upwards. Observations so far have confirmed the predictions of warming being made some 30 years ago. Recently we’ve been getting more specific predictions into the future, and as you keep an eye on trends you can (potentially) falsify the expectations from present physical understanding.

        Present understanding is that there is to be a persistent warming trend throughout this century; though (as has been noted consistently) this is not expected to be a steady trend. The expectation is that the main on-going trend should be apparent over 20 year windows or more; with 15 years or less showing a combination of this underlying trend with shorter term untrended variation.

        Cheers — Chris

      • at .15C you become a lukewarmer.

        Steven, what do you become at 0.13 °C/decade? That’s what I figure for the impact of rising CO2 in 1990. By 2000 AGW was up to to 0.16 °C/decade. Currently I figure AGW is running at 0.2 °C/decade.

        For those who’ve just tuned in, some people define AGW to be the impact of rising CO2 brought on by our land use changes, conversion of fossil fuels to energy, and flaring of same. I’m one of those people, why shouldn’t I be? Why shouldn’t anyone be? If you have a different definition of AGW, by all means put it on the table and let’s discuss it.

        Now the Keeling curve shows atmospheric CO2 to have been increasing extremely steadily. Hence with that definition of AGW it’s impossible for the impact of rising CO2 to be all over the place. That impact has to be rising very steadily.

        Which is the case for my AGW numbers above.

        As several million people have pointed out, CO2 isn’t the only thing driving global temperature or it would be rising as smoothly as CO2.

        Well, duh.

        Anyone conflating natural fluctuations in global temperature with those attributable to rising atmospheric CO2 is living in a state of sin.

        You must separate the natural and anthropogenic contributions to global temperature. Ideally you would do so to a precision of well under a millikelvin. If you can’t come even close to that level of precision then you can’t claim to understand climate change, because climate change works with very small variations in temperature, in case you hadn’t noticed.

    • Chris

      Why should we panic now with the warming of 0.15 deg C per decade, when we had similar warming rate from 1910 to 1940 when there was little human emission of CO2?

      http://bit.ly/9kJczm

      • We should not panic.

        We should, however, anticipate that the warming we see at present will continue, and that that we still have a say in how strong that warming will be; and plan accordingly without panic.

        The reason we should have high confidence in this conclusion is not extrapolation of trends or curve fitting; but physics of what drives temperatures and climate. This is a matter which tends to get lost in discussions such as those of Leake. Of the various “hypotheses”, only number 1 has a solid testable basis. The others invoke all kinds of unexplained cycles and shifts and so on without any suggestion of what could be driving them; and a major problem with the lack of indication of those cycles going back beyond the instrument record. That, combined with the idea that climate is insensitive and doesn’t change much in response to forcings becomes merely oxymoronic.

      • Chris

        Breaking the record into the apparent 30-year cycles (as Girma has done) there is the 30-year warming cycle from ~1911 to ~1940 (which was “statistically indistinguishable” from the latest 30-year warming cycle from ~1971 to ~2000, according to Phil Jones), followed by the 30-year cycle of slight cooling from ~1941 to ~1970 (which occurred despite the fact that CO2 emissions were beginning to accelerate as a result of the post-WWII boom years).
        http://www.woodfortrees.org/plot/hadcrut3vgl/from:1941/to:1970/plot/hadcrut3vgl/from:1941/to:1970/trend/plot/hadcrut3vgl/from:1911/to:1940/plot/hadcrut3vgl/from:1911/to:1940/trend/plot/hadcrut3vgl/from:1971/to:2000/plot/hadcrut3vgl/from:1971/to:2000/trend/plot/hadcrut3vgl/from:2001/to:2011/plot/hadcrut3vgl/from:2001/to:2011/trend

        The warming/cooling cycles are underlaid by a slight warming trend of around 0.5 to 0.6°C per century, like a sine curve on a tilted axis.

        It is quite apparent that these cycles, as well as the latest 11 years (starting in 2001 (which again shows slight cooling), bear little correlation with the steadily increasing CO2 levels.

        This is Girma’s point, and it is pretty hard to invalidate based on empirical evidence, as you will have to admit.

        One can deny that the cycles exist, but that would simply be sticking ones head in the sand in denial.

        The unanswered question remains: will the current trend of slight cooling continue for another 19 years or so to become another 30-year cooling cycle, or will it reverse to a new warming cycle?

        No one knows the answer to that question.

        Certainly not the scientists and climate models cited in IPCC AR4, who had projected that it would warm by 0.2°C per decade instead of cooling slightly, as it actually did.

        The second question (also unanswered) is: what has caused these observed ~30-year warming and cooling cycles?

        And finally, the third question could be: what has caused the underlying long-term warming trend of around 0.6°C per century?

        Max

      • Manaker, my reply was basically that we are not limited to observations of temperature. It’s physics which leads us to think that this isn’t just cycles.

        Looking at nothing at all but the temperature trends, without any consideration of what is actually causing them, would remove entirely my whole basis for expecting the 30 year trend to remain comparatively strong warming.

        I know Girma’s point was that the temperature data doesn’t (by itself) give strong evidence for a persistent ongoing trend. I agree that we need more. I think we HAVE more, and said so. I know we have have more, because it’s really the physics which is more my particular interest than statistics on trends.

      • Latimer Alder

        @chris ho-stuart

        The problem with your reliance on ‘the physics’, is that the pesky climate doesn’t seem to be behaving the way your theory tells us it should. And I’m disappointed to see that your response isn’t to go back to the physics and see what you’ve missed, but merely to reiterate that it’ll all work out fine in the end.

        H’mm

        Scientific history is littered with examples of ‘comprehensive theories’ that were 90%+ correct, but with just a few little problems in some dark corners. And it is the investigation of those troublesome phenomena that can lead to interesting and new insights. Einstein’s work on the photo-electric effect and discovery of the quantised nature of radiation is a classic example.

        So colour me unconvinced that you really understand this climate system. And colour me even more unconvinced by the argument that though it is impossible to forecast the climate 5 years away, you are perfectly capable of doing so 50 or 100 years out.

        Unless and until you can give a better understanding of the recent plateau in temperatures it seems to me that you have a lot more work to do. And that ‘It’s the carbon dioxide, stupid!’, may prove to be a far too simplistic theory.

      • Chris

        Thanks for your response.

        I think you have pinpointed where our basic disagreement lies.

        You cite “physics” (rather than “physical observations”) as the basis for the postulations leading to the CAGW premise.

        By this, I suppose you are referring to greenhouse theory or climate sensitivity hypotheses used in the climate model simulations.

        These are great, but as a rational skeptic, I would like to see empirical data to validate the hypotheses (which you call “physics”).

        If the “physics” tell me one thing, but the “physical observations” are showing me something else, I’ll go with the physical observations, especially in a science that is still in its infancy, such as climate science.

        Until these hypotheses (your “physics”) are validated by empirical evidence, based on real-time physical observations or reproducible experimentation, they remain uncorroborated hypotheses.

        This is how “physics” (and all other sciences) work, Chris. Hypotheses and theories are tested against empirical evidence. If the empirical evidence shows that they can pass repeated falsification attempts, they can become “corroborated hypotheses” and eventually “reliable scientific data”. The CAGW hypothesis has not passed this test.

        Show me (and Girma) the empirical evidence to support the CAGW hypothesis, i.e. that human GHG emissions have been the primary cause for past global warming and that this represents a serious potential threat to humanity and our environment unless these emissions are curtailed dramatically.

        But don’t just tell me it’s based on the “physics”.

        Max

      • Latimer Alder

        @manacker

        Well blow me down! You’re suggesting that Chris H-S goes out and does some experiementy thingies!

        Surely you know by now that such things are strictly discouraged in climatology. Chris would soon find his career at an end

        The Theory is Correct. The Observations are Wrong. Long live The Theory. A bas les experimentalists! The Glorious and Infallible IPCC has Written the One True Truth. Speak with One Voice And Praise The Theory. Shun and Dismiss the Well-Funded Big Oil Running Dog Denier Scum……….

      • Latimer says:

        The problem with your reliance on ‘the physics’, is that the pesky climate doesn’t seem to be behaving the way your theory tells us it should. And I’m disappointed to see that your response isn’t to go back to the physics and see what you’ve missed, but merely to reiterate that it’ll all work out fine in the end.

        Latimer, you’re just wrong there. The climate IS behaving consistently with what theory tells us. The people who say it isn’t are consistently distorting what expectations have actually been given.

        There are some glitches between theory and data here and there, sometimes resolved by better theory, sometimes by correcting data problems. That’s normal in all kinds of science, by the way. But we haven’t been looking at those problems here. The “problem” being raised HERE — a 15 year lull — simply IS NOT a conflict with theory.

        The point is — which I HAVE emphasized many times now — that the physical theories are incomplete. It’s not a solved or finished problem. They don’t, for example, adequately deal with short term variation. The short term variation is quite CONSISTENT with theory to date, but the theory is not at present able to predict them. (It may never do so beyond a narrow window, much as weather prediction is strongly limited in scope; this is where chaos shows up.) Physical modeling of many factors like cloud, or carbon cycle, or solar cycles, continue to be unsolved, and limit the skill of predictions.

        There are a whole HEAP of open questions in climate science, and we (or rather working scientists) are going back to the physics again and again and again. What on earth makes you think they are not??

        Manacker says:

        You cite “physics” (rather than “physical observations”) as the basis for the postulations leading to the CAGW premise.

        By this, I suppose you are referring to greenhouse theory or climate sensitivity hypotheses used in the climate model simulations.

        These are great, but as a rational skeptic, I would like to see empirical data to validate the hypotheses (which you call “physics”).

        Greenhouse theory is “theory” in the same sense as relativity is “theory”. It’s really very well understood physics with ample direct empirical confirmation, and actually one of the simplest and best solved problems in climate.

        Sensitivity isn’t a “hypothesis”. The hypotheses concern values for sensitivity. The most important constraints here are actually observational. Physical theory is not able to model the Earth well enough to give a definite prediction for sensitivity. That’s why it’s invariably given as a range of possible values.

        What the physical theory gives you quite definitely is that there IS a strong persistent contribution to heating up the planet. What it doesn’t give you particularly well is how much response there will be (sensitivity) and also what other local changes around the globe occur and how short term chaotic changes take place as the whole system settles to the changing conditions.

        There is, however, strong empirical reasons for lower bounds on sensitivity, which is where you get some fun debates from those who propose — in spite of all evidence to the contrary — a low value. Major positive feedbacks contributing increased sensitivity do have a well understood physical basis, but it is not complete. There’s a whole heck of a lot more going on and so theory does not tell you a particular value.

        In discussions here, some people don’t seem to understand how sensitivity is defined; they mix up equilibrium sensitivity with transient response sensitivity, or try to read equilibrium sensitivity from a temperature trend. That’s not falsifying theory. That’s just needing to learn a lot more before you can even follow discussions. The problem is I’m engaging here with people who operate at many levels.

        I don’t expect to convince you to change your mind all at once; nor can I possibly go into a full account of all the data and theory that is being applied — even if I knew it all, which I don’t.

        What I do know a fair bit about is the radiative physics in the atmosphere; at the level of a keen student, not a researcher.

      • Latimer Alder

        @chris ho-stuart

        ‘The people who say it isn’t are consistently distorting what expectations have actually been given.’

        Nope. 100% the wrong way about. Arse about face.

        If we have got the wrong end of the stick (and I by no means accept that we have), then the fault lies with you, not with us. If you have ‘given us the expectations, and we haven’t received them correctly, then it is your responsibility to make sure that we have them correctly, not ours to decode your mumbo jumbo into things that we interpret to your satisfaction.

        That is the basis of sound communication…YOU need to check that the message as sent has been received correctly…

        As to distorting expectations’, please show a consistent and frequent library of publications/presentations/public speeches designed for the general public where you and your colleagues have placed as much emphasis on the variability of recent temperatures as you have on the ‘inevitable’ long-term warming.

        Show me the portfolio of letters to the press where you have pointed out that stories discussing dangerous global warming should be moderated with the caveat that it may not actually warm an for up to a generation, but that we should still be very concerned.

        Show me the transcripts of the TV appearances where you and colleagues have appeared to reassure the public that the strange weather event du jour isn’t directly caused by global warming, but is just part of natural variation.

        I’ll take a wee wager with you that you can’t do any of those things. And the reason is that they never happened. Until very recently – prompted by the article in teh Sunday Times and other similar ones, the idea that ‘climate scientists have always known there will be a slowdown or stopping of temperature rise, but its all taken care of within our theory, so we still need to do something now’ has been a dirty little secret hidden in a dark place and rarely if ever let out for public examination. One can speculate why – not wishing to give the funding institutions an excuse to withdraw their largesse must be a strong hypothesis. And not wishing to halt an otherwise desired political ‘green’ process is another.

        But whatever the reason, you guys have NOT made it clear that these effects are likely to occur. And acusing us of deliberate misinterpretation is no way to escape your responsibilities to have done so.

        It is no wonder that the Man from the Met Office writes that he believes that there is a lot of work to do to regain the trust in climate science. With daft arguments lke this the amount of work needed becomes ever greater.

      • Chris, the basic problem is that sensitivity is an abstract concept that has little to do with reality, and the policy issue is about reality. To take an extreme example, suppose CO2 levels double but we fall into an ice age and the temp goes down 10 degrees. Is the sensitivity minus 10? No, of course not, because other factors are at play. The point is that radiative physics are only one aspect of climate dynamics, and the other aspects may matter more as far as reality is concerned. By analogy, abstractly one can throw a potato chip as far as a baseball, but don’t bet on it. In short, the focus on radiative physics is misguided.

      • Why should we panic now with the warming of 0.15 deg C per decade, when we had similar warming rate from 1910 to 1940 when there was little human emission of CO2?

        Depends on whether you’re planning for next week, next century, or next millennium.

        Girma, when would you say was the last time Earth experienced a rise of 15 °C in a mere millennium? What proportion of the planet’s species might fail to adapt to such a sudden change?

        Historically rates of change like that have led to mass extinctions.

        Anyway we’re currently hitting closer to 20 °C per millennium, and will be at double that rate by 2060 assuming business as usual.

        You are advocating business as usual, right, Girma? I’d hate to misrepresent you on that little detail.

      • Shorter Latimer: I bear no responsibility for any errors in my opinions – it’s all your fault.

      • CHS: In discussions here, some people don’t seem to understand how sensitivity is defined; they mix up equilibrium sensitivity with transient response sensitivity, or try to read equilibrium sensitivity from a temperature trend. That’s not falsifying theory. That’s just needing to learn a lot more before you can even follow discussions. The problem is I’m engaging here with people who operate at many levels.

        How many levels are you operating at? If one, how do you define climate sensitivity? If multiple levels, how are you different from anyone else here?

        Personally I operate at one level: I “try to read equilibrium sensitivity from a temperature trend” as you put it. Since I apparently to need to learn a lot more before I can even follow discussions, if you could convince me you had a more reliable approach you would have my full attention!

      • Markus Fitzhenry

        “”Vaughan Pratt | February 10, 2012 at 2:01 am |
        Girma, when would you say was the last time Earth experienced a rise of 15 °C in a mere millennium? What proportion of the planet’s species might fail to adapt to such a sudden change?
        You are advocating business as usual, right, Girma? I’d hate to misrepresent you on that little detail.””

        Vaughan,

        Do you think the following link to a pie chart graphic is still the business as usual, in the wider climate scientific community?

        http://eposters.agu.org/files/2011/12/Pratt_V_AGU_Poster_GC43B-092110.pdf

        It is all those bad humans need for fossil fuel energy that is going to exterminate them. Their bad behavior is going to make temperature to rise by 20 Deg, coupled with natural spatio-temporal chaotic systems;

        1. Irradiation and radiation of surface and atmosphere.
        2. Dynamic heat distributions of oceans.
        3. A multiple pole thermodynamic atmosphere.
        4. A Gravitational velocity spinning on an uneven axis.
        5. A Sun with fluctuation of solar isolation.
        6. Planetary harmonics.
        &. Atmospheric pressure and composition.

        Yep, definitely 74.8% anthropogenic and only 25.2% natural.
        I’d hate to misrepresent you on that little detail.

      • @michael

        ‘Shorter Latimer. I bear no responsibility for an errors in my opinions. It’s all your fault’

        But we weren’t discussing my opinions..for which I, of course bear full responsibility and am happy to do so.

        We were discussing instead this remarkable phrase from Chris Ho-Stuart.

        ‘The people who say it isn’t are consistently distorting what expectations have actually been given’

        Ever played the game ‘Chinese Whispers’? In which one person whispers a message to another, which is passed through a line of people until the last player announces the message to the entire group. Errors typically accumulate in the retellings, so the statement announced by the last player differs significantly, and often amusingly, from the one uttered by the first.

        Apart from being tremendous fun at children’s parties, it tells us something interesting and useful about communication in general. And that is that if you really want a message to be correctly received you need to build in a way of checking that it has been, otherwise it will accumulate errors.They may be caused by noise in transmission, by genuine misunderstanding, by inattention, by copying errors, by copying errors, by mispront, by language difficulties, by cosmic rays. But whatever their cause they are inevitable.

        So designers of communication systems pay special attention to ways of checking that the message has got through correctly. To use a relatively simple example if you watch any episode of Air Crash Investigation and you will see that the pilot always reads back his ATC instructions so that both parties know that it has been received as intended. This strategy of send/receive/check is universal in good comms systems design.

        Note especially the requirement that communication must be a two way process. It is not

        ‘I send, you receive’, but

        ‘I send, you receive, you send, I receive, we both check’

        So for CH-S to blithely state that we haven’t correctly receieved (and indeed have wilfully distorted) the message we have been given really highlights a number of points about climatology communication.

        Many climatologits have not grasped the two-way nature of communication at all. They are still stuck with the ‘I send, you receive’ model.

        We can see for example in the website ‘Real Climate’, which is entirely dedicated to such a one-way proposition. Its strap line ‘Climate science from climate scientists’ does not augur well that it is a 2-way street. And its comments policy only reinforces that idea.

        With no corresponding check of perception, they have no way of knowing what people’s expectation will be at the end of the game. And if it is hugely inconsistent with that they thought they had given, it really is of little value to blame the recipient.

        For it is they themselves who have chosen to restrict themselves to the one-way communication model. They who wilfully and deliberately choose to ignore contrary views – dismissing any objections with derision. They who choose the megaphone not the telephone as their way to disseminate their ‘message’. And, as in this case, when that mechanism fails as it has here, and hen it causes them acute public discomfort, it really ill-becomes them to blame the receiver for the failure.

        To reiterate: For my opinions I am happy to take full responsibility.

        But for the fact that they think their message may not have been received correctly by the masses, only the climatolgits themselves bear the blame.

      • @Markus Yep, definitely 74.8% anthropogenic and only 25.2% natural.
        I’d hate to misrepresent you on that little detail.

        If you found an error I’d greatly appreciate your drawing it to my attention. If not then I don’t understand the point of your remark, unless you’re finding those numbers a bitter pill. If you’re interpreting the chart as standard deviation instead of variance then I would certainly agree with you that under that interpretation the chart would be wildly inaccurate.

        Your recent reasoning in a three-component analytic model of long-term climate change, to me was illogical in several respects,

        Do you mean it was wrong or that you didn’t follow it? Happy to fix either one.

        but the biggest bias was your misanthropism.

        I’ll have to pass on that one. Understanding how “but the biggest” can serve as a connective between topics whose relationship has not been made clear is above my pay grade.

        your ad-hominem attack was no more than a condition of your preconceived ideals.

        Again I’m not following. An ad hominem argument is an appeal to a negative trait that is unrelated to the argument. How is someone’s inability to accept that their reasoning is circular irrelevant when that’s what I’m complaining about?

        Being a bank robber is a negative trait, but calling someone who’s robbing a bank a bank robber is not an ad hominem attack because it’s a relevant trait.

        In my 58 years hanging out with Aristotle, I’ve never seen a better protagonist with the fallacy than you.

        I take it you’re not a fan of constructive logic.

  64. Just think how much more we will all know in 10 years…and then again in 20 about the relative strength of solar and anthropogenic forcing. What better time than a Maunder minimum #2 to see first hand if attribution studies have even come close to identifying the underlying forcing from the increase in greenhouse gases.

    The last decade has been an interesting one. True, no contined increase in temps, though some pretty warm years. Will a new instrument record warm year or two occur in Solar Cycle 24, perhaps near the Max, especially if even moderate El niño sets up? How will complete skeptics of any AGW spin such an occurrence? And what of the long-term, multidecadal decline in Arctic sea ice? How might a sleepy sun for several decades impact that? Stay tuned…for the most exciting period on the history of climate study is about to begin!

    • It seems that some of us, at least, will have have learned something about climate and climate change. I hope that having a little knowledge of these issues will serve to make us more aware of what potential impacts our actions and that of other external influences could have on climate in particular and on our environment generally.

    • R. Gates

      Wisely stated Just think how much more we will all know in 10 years…and then again in 20 about the relative strength of solar and anthropogenic forcing

      This is precisely the point I was trying to make to Chris.

      We simply DO NOT KNOW whether it will continue to cool slightly as it has over the past 11 years, or start warming again.

      We don’t even know WHY it has warmed and cooled slightly in roughly 30-year half-cycles over the long-term record.

      We think we know (but aren’t sure) why there was an underlying warming trend of around 0.6 degC per century – but IF it continues to cool slightly over the next several years despite ever-increasing CO2 levels, we will have to revise our theory on that, as well.

      Yes. It is an exciting time for climate science – actually much more so than the much-ballyhooed IPCC late 20th century “poster period”, because we will get a real-life test of the CAGW hypothesis and assumptions, which are principally based upon that period.

      Max

    • R gates

      Your visits here are all too infrequent, guess you’re still trying to convert them all over at wuwt :)

      You say no continued increase in temperatures over the last decade. This is a refreshing admission from someone primarily on the agw side.

      We have had people coming up with all sorts of graphs to prove temperature is increasing, decreasing, or static.

      No snark here, but which graph would you cite that has a degree of authority, i.e one not manufactured on wood for trees using dubious end points and data.

      Tonyb

  65. Just a remark to the article by Jonathan Leake.

    If one picks 1998 as the “start date” for the current cycle of “lack of warming”, one arrives at an essentially flat trend (Met Office tells us: “Our records for the past 15 years suggest the world has warmed by about 0.051C over that period” ).

    If one takes only the past 10 years (2002-2011) one arrives at a more significant cooling rate of 0.1C per decade.

    There are good arguments for NOT starting in 1998 (a record high, strong El Nino year).

    Starting in 2002 (or 2001) gives a more pronounced trend, but only over a shorter time period.

    Cherry-picking?

    Max

    PS The fact of the matter is it is cooling slightly, as it did from around 1941 to around 1970 (not warming imperceptibly, as Met Office would have us believe).

    • You are ignoring the fact that short term trends change quite rapidly.

      Using HadCrut3, for example, the 10 year trends have the following sequence.
      0.29
      0.25
      0.28
      0.35
      0.33
      0.29
      0.24
      0.24
      0.09
      0.04
      0.07
      0.03
      -0.03
      -0.10

      That’s going from 1989-1999 inclusive at the top, to 2004-2011 inclusive, at the bottom. You might like to play with the spreadsheet I’ve made available at SkyDragon to do these calculations quickly.

      Swings around a bit, doesn’t it? That’s why we DON’T use the 10 year trend as you have done. That’s why it’s just silly to say Met Office is trying to make us believe what isn’t “actually” the case. The Met Office, after all, specified the time span. What they actually said is (via Leake’s article) is this:

      “Our records for the past 15 years suggest the world has warmed by about 0.051C over that period,”

      Why would you pick a short term, which is even LESS reliable as an indicator of what’s coming, as what is “actually” happening now? I call BS on that. (BS being “Bad Science”, of course. :-)

      What’s “actually” happening isn’t a trend over any window. Next year might be warmer or cooler; the changes “now” aren’t given by ANY trend. The trend over a window is a diagnostic, used for testing hypotheses. What is ACTUALLY happening now is that the atmospheric greenhouse effect is getting stronger; and at the same time the circulations of water and air and heat and cloud and so on around the globe are going on their merry chaotic way, meaning that we are going to have unpredictable short term variations while there is a continual flow of heat into the ocean from the energy imbalance between what is being emitted and what is being absorbed.

      It’s the physics that matters. The behaviour of temperature, along with a lot of other observations, is all backing up the general picture of the planet shifting climate to get into balance with the new atmospheric composition. It’s not just extrapolating trends. It’s classic conventional science, digging into material causes, and forming and testing hypotheses.

      • Chris

        Again, you cite the “physics”: It’s the physics that matters (rather than the “physical observations”).

        See my earlier post for the reasons why its the “physical observations” that matter, because they provide the empirical evidence for the “physics”.

        Max

      • Chris

        Your 10-year trend analysis confirms one thing.

        There has been a shift in the decadal rates of temperature change since the decade starting in 1989, from one of strong warming to one of slight warming to one of slight cooling.

        Will this trend continue?

        Who knows?

        At any rate, IPCC missed it in their projection of continued strong decadal warming.

        Max

      • Well, you excuse the models from explaining short-term variance and trends. That leaves long-term. Which, of course, can’t be validated till a long term has passed. So we’ll just have to trust the models are right!

        Nice work if you can get it.

        But I dooone thang sew. Trust in the models seems to be a VERY expensive wager.

  66. Chris

    You cannot justify cherry-picking 1998 as the “start date of a 15-year trend showing imperceptible warming” (as Met Office did) versus cherry-picking the most recent 10-year period starting in 2002, which shows a statistically significant (if shorter) cooling trend.

    Let me give you my opinion as to WHY Met Office cherry-picked 1998 (instead of 2002): so they could still claim a warming trend, even a statistically insignificant one, rather than (oh horrors!) a cooling trend, and then (wink-wink) remind us that the trend was started in a record high El Nino year..

    The IPCC projection of +0.2C per decade warming looks much worse when compared to actual -0.1C per decade cooling than it does when compared to +0.03C per decade warming – right? [Error is only 0.17C rather than 0.3C per decade.]

    And even that +0.03C per decade warming sounds a bit better when expressed as +0.05C warming over a 15-year period – right? [Casual observers might conclude that the IPCC error was only 0.15C per decade.]

    Chris, that is what cherry-picking and word-smithing is all about, and Met Office as well as IPCC are experts at both.

    Max

    • You cannot justify cherry-picking 1998 as the “start date of a 15-year trend showing imperceptible warming” (as Met Office did) versus cherry-picking the most recent 10-year period starting in 2002, which shows a statistically significant (if shorter) cooling trend.

      They DIDN’T cherry pick anything. They were asked about the recent trend over 15 years, and gave the answer.

      Good heavens man! That’s about as unfair an accusation as you could possibly give! They didn’t pick the window length at all.

      The Met office DOES NOT pick any particular window as being the “actual trend”.

      Careful studies of data, such as that by Santer cited previously, attempt to give a scale to the window length where you start to see the underlying trend. That’s not cherry picking either; that’s making a testable inference based on looking at all the data; one that will be confirmed or falsified as time goes by.

  67. Max and Chris

    At 3.42 above I suggested that R Gates post an authoritative graph as it can’t be cooling AND warming. It is doing one or the other or is static.

    It can be expressed over a 15 or 10 year period so do either of you two (or anyone else) care to oblige?
    tonyb

    • Climatereason, the spreadsheet I have provided at the thread in “SkyDragon” (Recent trends in global temperature) allows you fairly quickly to produce plots which give trends for four well known global datasets (GISS, NCDC, HadCrut3, UAH) plus one land only dataset (BEST). It allows you to enter a window length (in months) and the plot will then show the trend over every possible window of that length for each of the datasets. You can see how the trends increase and decrease with time.

      Is this “authoritative”? Science isn’t actually about “authoritative” answers. It’s when you get a conciliation from many lines of evidence that you begin to think science has a handle on something.

      Anyhow, those four datasets are all pretty close. There are differences and I know a bit about WHY there are differences, but that is not “authority”. That’s part of the messy business of science and replication and testing and falsification and so on.

      But in general I think we can have confidence that four together give a fair picture of how temperatures are changing over time. (It’s worth understanding what is actually being measured here — know how an “anomaly” is defined and calculated. Another topic.)

      I’ve given plots over there which show trends from moving windows of 15 and 20 years. You can easily generate others with the spreadsheet. The sources of data are given with links. Here’s a direct link, for example, to the image of a plot for trends with a 20 year window. linky. The vertical scale is the trend value, the horizontal scale is time, and each plot point represents the trend for the 20 year window centered at the given time.

      For example… the purple line is for HadCrut3. It shows a local high of 0.237 C/decade at the time 1994.333. This means that the 20 year window from April 1984 through to March 2004 inclusive shows a trend of +0.237

      Since then, the windows have declined. The most recent 20 year window is Jan 1992 through Dec 2011, and that has a trend of +0.155

      The plot tracks how the trend over the window changes and the window moves over the last century to now.

      I don’t give it as “authority”. If there are bugs, I want to know. If anyone wants to repeat the calculation, I give links to the data I used. But I do commend this as my best effort, which I think is correct, and which people can look at or use.

      The SkyDragon thread has more comment, links and the spreadsheet itself.

      • The four datasets are not pretty close, nor are they of equal credibility. I like UAH because it is a measuring instrument, not a complex statistical model. It shows no warming from it’s beginning (1978) until 1997. It shows no warming from 2001 until now. But then second flat line is higher than the first flat line. The step up occurred during the big ENSO.

        There is no trend here, just a step function. No physical trend whatsoever. No evidence of GHG warming whatsoever. The other datasets disagree, of course. The point is that there is no simple evidence such as you claim. I personally think the UAH data is sufficient to falsify AGW. But in no case is it simple.

      • There is no trend here, just a step function. No physical trend whatsoever. No evidence of GHG warming whatsoever. The other datasets disagree, of course.

        If it will set your mind at ease, David, the other datasets actually agree. For example HADCRUT3 is just a step function whose steps average 27 years in length. Those steps are even longer on average than the ones in the UAH dataset. No physical trend whatsoever. No evidence of GHG warming whatsoever. The other datasets don’t disagree, they agree. You’re absolutely right about climate being flat.

        Incidentally the six HADCRUT steps show a net decline of 0.036+0+0.012+0.01+0.03+0.067 = 0.155 °C when you add them up. How does that compare to the net decline of the UAH steps?

        I personally think the UAH data is sufficient to falsify AGW.

        As David has made clear on this and many occasions, his standards as to what it will take to convince him that AGW is false are very high. I personally think that for most skeptics a cold day in July is sufficient to falsify AGW. Imagine David’s uncertainty before the UAH data became available.

  68. Chris Ho-Stuart

    I know Girma’s point was that the temperature data doesn’t (by itself) give strong evidence for a persistent ongoing trend. I agree that we need more.

    Thank you.

    In my climate debate against the AGW side, you are the first one to admit the above. Hat tip to you Chris.

    Chris, if “we need more,” before dotting our i’s and crossing our t’s, why do we the educated class scare billions of our world’s uninformed?

    Chris, have you looked at a paper ( http://bit.ly/nfQr92 ) co-authored by Mann that describes the oscillation in the global mean temperature to be due to Thermohaline circulation?

    • No, I had not seen that paper. It looks interesting, and the general notion makes good sense. That’s not a judgement on the paper or the work, which I haven’t read. I’ve seen similar kinds of work on shorter period changes associated with the Pacific Southern Oscillation.

    • PS. Don’t forget the next sentence after “I agree that we need more.” in the paragraph you partially quote.

      The next sentence is “I think we HAVE more, and said so.”

      It is the combination of all lines of evidence and tested theory which is the basis for the educated folks (that is, folks educated in climate science in particular) giving useful information on that technical subject, concerning what we do actually know about climate and what it’s doing.

      Whether it is “scarey” or not is beside the point. The aim is to give what information we have. Which does indeed confirm about as well as science confirms anything that the planet is heating up primarily because of human caused changes to the atmosphere. That’s not just a guess. It’s the overwhelming conclusion supported using all available evidence and indicated by best available physical theory.

      How much it will heat up and what attendant patterns of change will be seen around the globe is not so definite. That’s important information wanted to plan for the future, and that’s being worked on. Conclusions are being drawn, though generally they are more tentative, as befits the more limited level of scientific support for the such conclusions.

      • Chris

        According to Mann himself (http://bit.ly/nfQr92 , Figure 4) , expect slight cooling until 2030.

        IPCC’s 0.2 deg C per decade warming is being falsified.

      • Girma says:

        According to Mann himself (http://bit.ly/nfQr92 , Figure 4) , expect slight cooling until 2030.

        IPCC’s 0.2 deg C per decade warming is being falsified.

        That’s not correct. You’ve read the paper wrong.

        Look at the figure again. It is NOT showing temperature, but the “THC anomaly”. That is, according to Mann et al, the THC will be contributing a small cooling effect. Actually, it should be “Knight et al”; Knight is the first author.

        This is a proposal for part of the contribution to natural variability above and below the main trend… but an unusually long period contribution, which is indeed most interesting.

        What the paper ACTUALLY says of the overall temperature trend is seen in the conclusion. Here are the last two sentences of the paper:

        This natural reduction would accelerate anticipated anthropogenic THC weakening, and the associated AMO change would partially offset expected Northern Hemisphere warming. This effect needs to be taken into account in producing more realistic predictions of future climate change.

        That “partially offset” means that Knight et al are proposing that the main warming trend is greater than the quasi-periodic THC/AMO contribution to global temperature. Hence the paper is not predicting cooling, but that this effect will mask of some of the warming, leading to a reduction in the warming trend over that scale.

        This fits pretty well with what I had suggested earlier, where I anticipated an upcoming 20 year trend of 0.15 to 0.20 C/decade… the low end of IPCC projections. But my guess was simply based on extrapolation, not on a particular physical theory. I don’t use that the prejudge Knight et al’s idea, even though it is fits pretty well with my existing perspective. The paper will need to stand or fall on its own merits.

        Knight et al are not proposing an alternative to the main drivers of global temperature. They are proposing a specific factor contributing to secondary and untrended variation, which (if correct) might allow for better mid-term forecasts on the scale of several decades.

        It doesn’t falsify the IPCC projections, for two reasons.
        (1) FIrst, it’s not well confirmed. It’s a proposal; not a refutation of all alternatives.
        (2) Second, it’s not really an alternative anyway. It would, if it holds up, give a constraint on the mid term 20 year projection, to let it be nailed down a bit more tightly, towards the lower end of expections. Instead of “about” 0.2, it would be “a bit under” 0.2.

        When I did the same thing above, I got called a “lukewarmer”, which gave me a chuckle. :-)

  69. Chris, question to you!

    Here is the global mean temperature data => http://bit.ly/Aei4Nd

    Why do most of the global mean temperature peaks lie on a straight line?

    Why do most of the global mean temperature valleys lie on a straight line?

    Why do these two global mean temperature boundary lines parallel?

    Why is the slope of these boundary lines equal to the trend for the whole data from 1880 to 2010?

    • Why do most of the global mean temperature peaks lie on a straight line?

      Why do most of the global mean temperature valleys lie on a straight line?

      They don’t, as far as I can see.

      If you think you can see some kind of pattern by eyeballing a graph, the proper thing is to get some kind of sensible significance test. That’s not easy; you should really check with a professional statistician. I’m not one of those. Sorry.

      Why do these two global mean temperature boundary lines parallel?

      Because that’s how you defined them; they the same line with different offsets.

      If you want to make a non-trivial comparison, you need to actually calculate two lines independently, and then see if they are parallel. But what definition would you use?

      As it stands, note that your upper line has a couple of outlier peaks well above the upper line, and the lower one…. doesn’t.

      Why is the slope of these boundary lines equal to the trend for the whole data from 1880 to 2010?

      As before… they are the same line, just with different offsets. It’s because that’s what you’ve chosen to plot.

      This is not a good place for these kinds of questions; this is really more about learning a bit of simple statistics.

      • I have to say, I agree with Chris here.

      • Chris

        The global mean temperature (GMT) data shows a single pattern of a warming trend of 0.06 deg C per decade with an oscillation of 0.5 deg C every 30 years => http://bit.ly/Aei4Nd

        This mean that during cooling cycle, the magnitude of the cooling every 30 years is

        –0.5 + 0.06*3 = -0.32 deg C

        During the warming cycle, the magnitude of the warming every 30 years is

        +0.5 + 0.06*3 = +0.68 deg C

        Starting from GMT value of –0.27 for 1880, we can calculate approximate values for the other peaks and valley as follows:

        GMT for 1910s = -0.27 – 0.32 = -0.59 deg C

        GMT for 1940s = -0.59 + 0.68 = 0.09 deg C

        GMT for 1970s = 0.09 – 0.32 = -0.23 deg C

        GMT for 2000s = -0.23 + 0.68 = 0.45 deg C

        These values are very close to the observed values. Is this just coincidence?

        Let us make predictions:

        GMT for 2030s = 0.45 – 0.32 = 0.13 deg C

        If the observed temperature approximately matches this value, this will demonstrate the variation in climate is natural.

      • Chris Ho-Stuart: This is not a good place for these kinds of questions; this is really more about learning a bit of simple statistics.

        This is not a case for simple statistics. Descriptively, Girma is correct, but needs to use “quantile regression”.

  70. RealClimate has an article today updating model-data comparisons,

    http://www.realclimate.org/index.php/archives/2012/02/2011-updates-to-model-data-comparisons/

    The first figure shows that the observations, including the last 15 years fall well within the uncertainty of the IPCC projections for the “business as usual” scenario A1B.

    • Any agreement between observations and IPCC projections (GHG modelled) is pure coincidence. This will be demonstrated in the next decade(s).

      • Prof. Curry stated “Yes, but the very small positive trend is not consistent with the expectation of 0.2C/decade provided by the IPCC AR4”. The RealClimate analysis demonstrates unequivocally that this statement is factually incorrect. This is becuase Prof. Curry failed to consider the uncertainty around the expected trend. This may not have been stated explicitly in the summary for policymakers, but perhaps that is because it was a summary for policy makers.

        Blustering about what the observations may or may not show in the next dacades does not change the fact one iota that Prof. Curry was simply wrong about this.

      • Policymakers are allowed to look @ thermometers, to settle their uncertainty about who was wrong.
        ===============

      • Dikran –

        Prof. Curry stated “Yes, but the very small positive trend is not consistent with the expectation of 0.2C/decade provided by the IPCC AR4″. The RealClimate analysis demonstrates unequivocally that this statement is factually incorrect

        I tried asking Judith a related question.

        http://judithcurry.com/2012/02/07/trends-change-points-hypotheses/#comment-166946

        For some reason she chose not to respond. I assumed it was because I wasn’t sophisticated nor intelligent enough to understand that the answer to my question was obvious.

        Any chance that you might speak to the question of whether 15 years, or even 30 years of “pauses” would be “expected,” albeit rarely?

      • Pick a number, any number will do. You pays your money and you takes your chances.
        =============

      • Joshua: I assumed it was because I wasn’t sophisticated nor intelligent enough to understand that the answer to my question was obvious.

        Not quite. It’s because, whatever your actual sophistication and intelligence, you write stupidly on purpose. As you wrote in another post, you try to prove people wrong using the technique of “Socratic Dialogues”, which in this venue are pointless.

    • Overall, given the latest set of data points, we can conclude (once again) that global warming continues.

      Did not the IPCC predict the temperatures would be above for the case emission was held at the 2000 level?

      http://bit.ly/wVWllY

      • Girma, you’ve linked to this picture a number of times now.

        It is a modification of the ipcc figure, the original of which is seen here:
        Figure TS.26, AR4.

        The original figure is a comparison of predictions with data.

        Your figure is a modification. You’ve somehow REMOVED the data from the original figure, and added in your own version of the data.

        That’s not honest.

        It’s also technically incompetent on two levels.

        First, the projections are of central tendency, which means that they should be compared with smoothed data, filtering out short term variations. That is indeed what the original figure uses. You’ve removed that, and replaced it with unsmoothed data. Note that the original still shows the unsmoothed data points with black dots, and the smooth with a black line. That’s the major problem.

        Second, the modified data is not quite aligned right. It seems to be shifted down a little.

        The correct and more honest thing to do would have been the following.

        KEEP ALL the original figure, including the observational data already supplied. Editing the image to remove parts of it, without even saying that’s what you’ve done, is reprehensible.

        Extend with additional data available since publication, making sure it is correctly aligned with the existing plot, and identified clearly as added to the original. Purple is fine.

        Add in a new longer smooth data line, using “decadal averages” as done in the original figure. That’s what you should compare, not raw data.

        Do all this, and you’ll find (to my own total lack of surprise) that there’s no falsification at all.

      • Chris

        KEEP ALL the original figure, including the observational data already supplied. Editing the image to remove parts of it, without even saying that’s what you’ve done, is reprehensible.

        Before lashing out, please know that I have not drawn that graph.

        What matters is what happened after publication.

        The main thing is that IPCC projected for a warming of 0.1 deg C per decade if CO2 emission were held constant at the 2000 level.

        However, the globe is on a cooling trend right now => http://bit.ly/nz6PFx, and there is no restriction in CO2 emission.

        This clearly falsifies IPCC projections.

      • Since the IPCC has not ever predicted 10 year trends, which is how you get “cooling”, you are, again, flatly wrong. The IPCC expectations are for a warming trend that shows up over longer time scales. On short scales, trends are expected to be substantially above and below the persistent long term trend. The IPCC expectation is for a trend of about 0.2 C/decade. That trend should be sought over windows of 20 years or more. The “about” in this case means something from 0.15 to 0.3

        I personally would bet on the trend for 2000-2020 to be a bit under 0.2, which is still in line with the given uncertainty levels.

        You are responsible for choosing to cite that image, no matter what clown produced it. The person who produced it doesn’t actually know what is being predicted, or more likely (given that the original smooth of observations was deliberately removed) has deliberately obscured the matter. If you didn’t produce the image, then it would seem you’ve been sucked in badly. It most definitely does NOT show any falsification.

        To the extent you think it does, you are merely refusing to use what is actually explicit in IPCC expectations. It is most certainly not, and never has been, trends over 10 years!

    • Yep, still doing a fine job tracking scenario C, which should put 2100 temperatures under 2C.
      Adjusting Arrhenius’ latitudinal predictions seems to show a non-linear sensitivity.
      http://i122.photobucket.com/albums/o252/captdallas2/sensitivitybylatitudeestimate.png

      Of course, that is just a rough estimate, but interesting.

      • Markus Fitzhenry

        Vaughan, The gentleman asked, he did not state;

        1. Is there anybody here who can admit that when the stated uncertainty of the projection is considered Prof. Curry’s assertion is incorrect?

        Have you got some sort of circular reasoning problem when your ad-hominem attack was no more than a condition of your preconceived ideals.

        “”On both sides of the climate debate, the test that people seem to be applying as to whether their reasoning is logical is whether it leads to conclusions they already held.

        Your recent reasoning in a three-component analytic model of long-term climate change, to me was illogical in several respects, but the biggest bias was your misanthropism

        “”In my line of work, which for the last 35 years has been logic, this is known as circular reasoning.””

        My experience during that period in persuading people that they are using circular reasoning is that it is utterly impossible to do so. People have beliefs, and they simply refuse to attempt to imagine the opposite. Which is what you have to do in order to debug your reasoning.””

        Argumentum ad populum has been your argument here. In my 58 years hanging out with Aristotle, I’ve never seen a better protagonist with the fallacy than you.

      • @markus fitzhenry

        Here are the exact words used in the IPCC report

        ‘For the next two decades, a warming of about
        0.2°C per decade is projected for a range of SRES
        emission scenarios. Even if the concentrations of
        all greenhouse gases and aerosols had been kept
        constant at year 2000 levels, a further warming of
        about 0.1°C per decade would be expected’ (AR4 WG1 SPM p12)

        There is no discussion of uncertainties. No ‘if’s or ‘but’s. The whole para is highighted to stand out from the rest of the text. And it appears right slap bang under the heading ‘Projections of Future Changes in Climate’.

        This was their take home message to Bush and Blair and Merkel and Putin and other world leaders. To the press and the rest of the media. And to the interested general public. This was written n plain(ish) language for a lay audience to understand. There can be no ambiguity. This is the prediction.

      • Markus Fitzhenry

        Latimer,

        “”This was their take home message to Bush and Blair and Merkel and Putin and other world leaders. To the press and the rest of the media. And to the interested general public.””

        Didn’t scare me.

      • Latimre – what do you think the word ‘about’ means in the passage you have quoted?

      • Markus Fitzhenry

        Well it’s not like they said it was going to be zero. Louise?

      • @louise

        ‘Latimre – what do you think the word ‘about’ means in the passage you have quoted?’

        I think it means exactly what its common usage means.

        No use trying to wriggle. The statement is unequivocal. It was deliberately meant to be easily read and easily understood. The Summary for Policy Makers is not a legal document where every word can be parsed and analysed. It is there to influence policymakers.

        And it clearly states that they expect 0.2C warming per decade. Not 0.1C or 0.0C.

      • about – around, approximately etc etc.

        It’s a pretty weak argument to be trying to suggest that the SPM stands alone from the AR4.

      • @michael

        ‘It’s a pretty weak argument to be trying to suggest that the SPM stands alone from the AR4’

        ???

        Or is English not your first or second language and you have difficulty with the word ‘Summary’?

      • Lati,

        Brilliant – you’ve finally got it!

        Yes, it’s utterly stupid to declare what the AR4 says by only invoking the summary and ignoring the details in the technical section.

        And an english hint for you – common usage of ‘about’ is not ‘exactly’.

      • May I suggest that the source of confusion here is not over “about”, but whether a rate of “about 0.2 per decade” can be read as “about 0.2 for every decade”.

        The “0.2 per decade” is simply the magnitude of trend; the units of degrees per decade. It’s not an indication that every decade will see about that rise. The suggestion is that over TWO decades, you will see a rate of increase of about that magnitude.

        That prediction fails if the trend over the two decades is substantially different from 0.2.

        The prediction does not say you can look at the trend over one decade and see that trend. I won’t quibble over whether it could be worded more clearly; but the meaning is nevertheless the same as it has been for every IPCC report ever. It’s always been recognized that there’s lots of short term variation over a decade or so. It’s always be explicit that the rise is not expected to be steady.

      • Chris,

        Yes, that is absolutely clear…..for anyone who reads the document in good faith.

        Those who find it convenient to misunderstand will continue to do so.

      • @markus fitzhenry

        ‘Didn’t scare me’

        Nor me. No even a dampness in the knicker area. No palpitations whatsoever. BP steady – both systolic and diastolic.

        And absolutely not even the stirring of the idea that I must unbutton my wallet, throw twenties around like confetti and run around shouting

        ‘Oh my God, we must Do Something. Here, spend lots and lots and of money, however futile it is’

      • @chris

        If they wanted us to read it the way you describe, they were perfectly at liberty to have written it with your convoluted interpretation in mind.

        They could have written

        ‘we expect that the temperature will rise by about 1.0C in 50 years, although warming may be uneven’ which would have covered the same point – albeit with slightly different emphasis..

        They didn’t. They deliberately chose to use the decadal time frame, not the century or the annual or any of the other scales that they could have chosen to illustrate their point.

        So I don’t think it is any sort of a reasonable interpretation to believe that this was supposed to be taken as ‘0.2C in some decades (and probably not this one coming up now)’.

      • @chris h-s

        and partly @ michael

        ‘It’s always been recognized that there’s lots of short term variation over a decade or so. It’s always be explicit that the rise is not expected to be steady’

        Chris, this is the Summary for Policy Makers. Guess who it is aimed at? Yep, Policy Makers. The clue is in the name.

        And who might the policy makers be? Senior politicos and their staffs primarily. Why was this summary written, rather than just dump AR4 in its entirety on their desk and say ‘there you go matey..its all in there’? Because these guys are busy people, have limited time to read things, probably have a zillion other important things to worry about and may have only limited interest in the topic. So, like an ad on the telly, it has to be short and sweet and cover the main points of a topic that the recipient may have only limited (or no) background knowledge about.

        It may well be that in geeksville, arizona ‘it has always been recognised’ that there will be short term variation. For those whose careers are funded just to obsess about the last jot and tittle of every word in the report this may be common currency (though historical records of this being so seem to be hard to come by).

        But this is not the case for the occupant of the White House, or the Elysee Palace or 10 Downing Street or wherever it may be. Th eones at whom the SPM is aimed. They likely know little and care less about the historical conventions of the IPCC and its implicit caveats. They just have document on their desk called ‘Summary for Policy Makers’, and quite reasonably expect that it should give them a quick read and a decent understanding of the key points of the topic in hand. Probably enough for them to incorporate something about it in a speech and answer 1st level questions in Parliament or a press conference without making complete arses of themselves.

        And this document is made available to the general public as well (a good thing to do). So the interested layman might take exactly the same approach. That if he reads this he can hold his own with the regulars of the Dog and Duck or over coffee at work on the topic.

        I’ve written before about how misguided it is fro you to blame the recipient for them getting your message ‘wrong’. Here, it seems you compound the mistake bigtime.

        You do your cause no good just by leaping up and down and shouting ‘you’re all too stupid to understand what we tell you, scum’. Especially when you don’t seem to have taken the slightest trouble to move beyond megaphone communication.

        PS – I’m sure you know that implict assumptions aren’t worth the paper they’re not written on.

      • Latimer,

        Your brand of disingenuousness is what gives ‘skeptics’ a bad name.

        Despite your wish that policy makers are as stupid as you pretend to be, here is what the SPM says to start,

        “The basis for substantive paragraphs in this Summary for Policymakers can be found in the chapter sections specified in curly brackets.”

        And are there “curly brackets” after the paragraph you keep partially quoting????

        Yes;
        “For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. {10.3, 10.7} ”

        Which point the policy makers to “the basis” of that summary.

        Do you really want to keep playing stupid?

      • I am so used to the unit “degrees per decade” that it would never even occur to me to take that as meaning “degrees for every decade”, or an indication of a time frame. Especially when the time frame was explicitly given as two decades in the same sentence.

        The trend over 10 years varies enormously. It’s been negative a number of times in recent decades; and also very high; over 0.4 at times. It’s not something you can reasonably predict.

        There are two wordings of the prediction you are speaking about. In the technical summary, they say:

        Committed climate change (see Box TS.9) due to atmospheric composition in the year 2000 corresponds to a warming trend of about 0.1°C per decade over the next two decades, in the absence of large changes in volcanic or solar forcing. About twice as much warming (0.2°C per decade) would be expected if emissions were
        to fall within the range of the SRES marker scenarios.

        That phrasing seems okay: “degrees per decade over the next two decades”. The “per decade” is the unit; the “over the next two decades” is the window.

        In the summary for policy makers, it’s slightly different.
        In the summary for policy makers, they say:

        For the next two decades, a warming of about 0.2°C per decade is projected for a range of SRES emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected. {10.3, 10.7}

        Using “over the next two decades” might have been better than “for the next two decades”, but at this point I think the more serious problem is a willful determination to take the wrong reading.

      • @michael

        I don’t doubt there are curly brackets all over the place. Just like there are references academic papers and in some popular history books. They are there to guide the very interested reader to further material. Big deal.

        A Summary should be what it claims to be. If you really need to read all the other stuff because you are otherwise missing really important stuff then it ain’t a summary it’s a ramble. This is clearly entitled ‘Summary’, and does not say ‘BTW you guys need to read all the rest as well because I just can’t be arsed to write a proper summary’

        You and Chris H-S keep falling into the trap of trying to say that what was written and published for all the world – and all the world leaders – to see doesn’t mean what it actually means. That there is some sort of code known to the cognoscenti of the IPCC that makes the language mean something different from its common meaning. That we should all have known that the author had hos fingers crossed when he wrote it. Or that it was the Third Wednesday after the Feast of Walpurgis and Beltane, so that words take on a different meaning.

        And then, to compound the felony, you wander about claiming that its all our fault. Words almost fail me, so I will use an abbreviation.

        BS!

      • @chris h-s

        ‘I am so used to the unit “degrees per decade” that it would never even occur to me to take that as meaning “degrees for every decade”, or an indication of a time frame’

        You’re doing a great job of emphasising my oft-repeated point about communication. You – as somebody involved in this professionally – may have some specific meaning that you are so used to that you never even notice it. And maybe that is fine for discussion with your immediate colleagues. Every field has its jargon, so this is no surprise.

        But when you are writing for a wider sphere, you must be just as careful with your language.and phrasing as I hope you are with the numbers.

        In this case they were writing for non specialists in an attempt to make some sense of all the technical stuff in the rest of the report. It matters not a jot what you take it to mean. What matters is what the intended audience takes it to mean. And it is quite reasonable for them to expect that the language used will be in common usage and the meanings will be the common meaning.

        And if a phrase or sentence or paragraph is possibly ambiguous, it is the author’s responsibility to make sure that such ambiguity is eliminated. It should not be the reader’s task to try to guess which meaning was intended.

        The common meaning of ‘about 0.2C per decade’ is perfectly clear. If you choose to interpret it differently that is your choice. But you cannot accuse those who see it differently as wilfully distorting it.

      • MIchael

        Yr “Yes, it’s utterly stupid to declare what the AR4 says by only invoking the summary and ignoring the details in the technical section.”

        O. K. Michael, I got it. When dealing with you and your pals–the “team”–we must always read the fine print. You’ve made your point.

        And we also now know, thanks to you, Michael, that any decision-maker that relies on the weasel-worded summary statements appearing in your profession’s most prestigious guide for policy-makers is “stupid”, unless that policy-maker has also read and digested every fine-print detail of the whole report.

        And finally, we know, Michael, those cleverly-worded, summary statements in the AR4 report are just a sound-bite friendly, agit-prop resource. You know, the sort of “good stuff” the team’s Big-Green trough-masters can draw on to whip-up decorative, “scientific” justifications for their CAGW scams, as needed. Like I said, I got it.

      • Lati,

        That was just pathetic.

        I love the smell of desperation in the morning.

    • Dikran,
      No, what RC has done is toss up a lot of bull dust, and you believers, having an appetite for bull dust, think it is wonderful.
      RC is a pure propaganda site, and your quoting them is no better than some low level apparatchik of the USSR quoting Pravda.
      I look forward to hearing how RC explains away the fact that the IPCC was completely wrong about Himalayan Glaciers:
      http://www.guardian.co.uk/environment/2012/feb/08/glaciers-mountains

      • It is deeply sad that whenever in this debate an assertion is shown to be unquivocally incorrect, rather than accept that it is incorrect, the response is an attack on the source or an attempt to move the discussion onto another topic (Himalayan glaciers).

        RC would be stupid to present a false analysis. The AR4 model runs are all archived and publically available, so if they misrepresented them it would be straightforward to expose the falsehood. The ball is in your court, present an analysis that proves RC wrong; I am a rational man, I am swayed by logical reasoning, but I am not swayed by ad-hominems or rhetoric or bluster.

      • It is deeply sad that you confuse what takes place at RC as conclusive of anything other than Schmidt’s bloviation.
        RC has been, by your definition, stupid for quite some time.
        Your defense tactic is ridiculous.

      • as I said, “I am swayed by logical reasoning, but I am not swayed by ad-hominems or rhetoric or bluster”.

      • You should understand, d. mars. that Skep. Sci. is a deeply ironic blog title, given your evident example of deep irony.
        =====================

      • yet another ad-hominem (attacking the source of an argument in place of an attack on the content), is deeply unconvincing.

      • That crew, dm, is deeply deceitful. Sadder than deceiving you, they’ve deceived themselves.
        ==============

      • Dikran,
        I followed your link from the RC page. I acknowledge that 2011 fell within the uncertainty range of the model estimates, althought the range was 0.8C wide. It is too soon to tell the accuracy of the models in the AR4 report. More interestingly, temperatures have been below Hansens Scenario C since 2003. This is the scenario, where draconain cuts would keep atmospheric CO2 concentrations constant at year 2000 levels (the best case scenario, which he felt was highly unlikely). Hansen has stated that the cause for his is the large increase in sulfate aerosols resulting from Chineses coal burning. RC glosses over these disparities, and instead focuses on trends longer than 15 years. A few posters asked about what would happen if the current 15-year trend (-.009C/decade – CRU3)continued, but Gavin seemed to deflect these.
        My question to you is how long would such a trend need to last before we begin to rethink these models? Gavin seems to think that not much will change this year.

      • DM,
        You are clearly swayed by argument and bluster dressed up all sciencey.

      • DanH The models need rethinking continuously, that is the way science works and indeed is what the climate modellers do. They are always looking to include more physics so that the models become a better representation of reality. The models tell us the likely consequences of our actions based on our best understanding of the physics.

        The key point here is that the observations are consistent with model projections, I have no objection to people criticising the models as long as the objection has a basis in fact. This one doesn’t and promulgating it is merely reducing the signal to noise ratio of the discussion, so it is in the best interested of both camps to drop it.

      • I’m not sure you’re getting the point of the uncertainties: it’s not unlikely for a climate system with a sensitivity of 2-4.5ºC to show relatively little warming across a given short interval (e.g. 11 years) even when the average rate of warming, across a longer period encompassing that interval, is about 0.2ºC.

        Therefore, you can’t make any significant statements about sensitivity from this data.

        You also might be interested to know that the IPCC range of uncertainty is not stratified by sensitivity across this short period. Some of the lowest trends come from higher sensitivity models, some of the highest trends come from low sensitivity models.

        I should note that I do think 0.2ºC/Decade is probably a small overestimate though this is more likely due to the overly large forcings in most of the models rather than having any clear implications for sensitivity. I think the current warming rate is closer to ~0.15ºC/Decade. One thing that hasn’t been mentioned earlier in the thread is the word ‘about’, which has historically been used by the IPCC in a way that should really be written as ‘ABOUT’ in big letters.

      • PaulS said, “I should note that I do think 0.2ºC/Decade is probably a small overestimate though this is more likely due to the overly large forcings in most of the models rather than having any clear implications for sensitivity. I think the current warming rate is closer to ~0.15ºC/Decade. One thing that hasn’t been mentioned earlier in the thread is the word ‘about’, which has historically been used by the IPCC in a way that should really be written as ‘ABOUT’ in big letters.”

        Agreed, ~0.15 with approximately +/- 0.15 natural variability. That is a huge difference in initial estimates and would make a huge difference in planning for and the cost of preparing for the future. That’s the point.

        http://i122.photobucket.com/albums/o252/captdallas2/ar4smilie.png

        This plot was from the IPCC AR4, modified by Girma with an added uncertainty added by myself, smilie wearing shades :)

        Definitely not long enough for a confident trend, but it looks like we are ABOUT to establish one with major policy implications.

        Of course, how creatively AR5 handles the Antarctic, mid-tropo, lower strat and tropics would also have major policy implications.

      • Impressive work finding that post.

        Regarding what you were saying about ‘falsification’ of scenarios one interesting thing to look at is what scenario we followed over the past 11 years. In terms of emissions the A1B / A2 pathways are pretty close, but if you look at estimates of total radiative forcing change (e.g. from GISS) there is zero increase since 2000. This means that the scenario we have effectively followed is the ‘Year 2000 Constant Concentrations’ one, projecting about 0.1ºC/Decade.

      • Dikran,
        If the models are constantly being reworked to include the latest research, then why are so many people still using the AR4 model scenarios, which are about six years old? As I mentioned earlier, the observations are only consistnet with the models, because the models have such a large uncertainty associated with them. One would think that they would rework the models before the observations fall outside the 95% confidence level.
        Similarly to Paul,
        It appears that even 0.15C/decade is too high. While a 30-year trend line will yield a similar value (0.16), shorter or longer time frame do not. (The 15-year trend is essentially 0, the 60-year trend is 0.11, and the 90- and 120-year trends are 0.07C/decade). Some posters are critical of the short time interval, and rightly so, but why neglect the long term trend in favor of an intermediate timeframe? A long term warming of ~0.7C/century would experience short-term rates of both 0.15 and 0C/decade

      • While a 30-year trend line will yield a similar value (0.16), shorter or longer time frame do not. (The 15-year trend is essentially 0, the 60-year trend is 0.11, and the 90- and 120-year trends are 0.07C/decade). Some posters are critical of the short time interval, and rightly so, but why neglect the long term trend in favor of an intermediate timeframe?

        Because the theory isn’t that the climate should be warming at a certain rate by decree over any chosen timeframe. The theory is that climate will warm in proportion to changes in radiative forcing over time (+ equilibrium ‘pipeline’ warming). I’ll post the GISS forcing diagram again. Note that the forcing increase since 1950 is about 3 times that from 1880 to 1950, hence the theory would expect a greater rate of warming over the past 60 years compared to the past 130 years. There is also a, less clear, acceleration at around 1970 so again, we would expect the past 40 years to have a greater trend than the past 60.

        Likewise, see my previous post about RF change since 2000. The GISS estimate suggests there has been no net RF change over this period.

      • DanH the reason that we are still using the AR4 models is that organising a consistent set of scenarios and getting a large number of modelling groups to coordinate to produce the multi-model ensmeble is a large effort, which detracts from the time required for research. There will be a new set of model runs for the next IPCC report and I understand that work on this is already underway.

      • Dikran, If you take the IPCC model range, you include models that predict 1.5K increase for the 21st century. So to say that the observations are “within” the model uncertainty is in my book a virtually meaningless statement. I think Hansen’s 1988 scenarios were clearly wrong on 2 fronts. He overestimated the percentage of emissions that would remain in the atmosphere, by a very large margin actually. And his model had a high sensitivity. In my book, that is definitive evidence that Hansen was unduly alarmist. In fact, the error bars on the models are probably greater than 100% of the values for such things as temp anomoly. And that’s the problem we should all focus on, not endless debates about how we can “adjust” the data so its consistent with our theory and models.

    • Mr. Marsupial, perhaps you can help me out with this sensitivity thing. Seems the Antarctic is not warming because CO2 needs water vapor to work. The tropics are not warming as much because they have too much water vapor for CO2 to work properly. The mid-latitudes are not warming as expected because ? At least the northern high latitudes are working. That kinda contradict what Arrhenius predicted.

      Since, “we” know more than Arrhenius, is there a modeled out put by latitude that matches what is going on?

      http://redneckphysics.blogspot.com/2012/02/arrhenius-is-still-dead-but-his-mistake.html

      • Again this is an attempt to change the topic of the discussion rather than admit that Prof. Curry’s assertion is factually incorrect.

        SkepticalScience is a good place to ask questions like that, I would reccomend you try there (just pick a relevant article)

      • DM,
        No, your only tactic is to ignore what you do not like.

      • Mr. Marsupical,

        I’m sorry, silly me. I thought that with Hypothesis II latitudinal sensitivity of the past 120 years might indicate somewhat natural variations impact on the climate sensitivity to CO2 increase. Then an average sensitivity based on the latitudinal trends being 1.48C per doubling might be some indication of future response to CO2, which appears to be somewhat less than 0.2C per, though still within the confidence interval of the model predictions, just closer to scenario C.

      • Which is irrelevant to the discussion of whether Prof. Curry’s assertion about the observations being inconsistent with IPCC projections (and hence falsifying hypothesis I) is correct.

        Is there anybody here who can admit that when the stated uncertainty of the projection is considered Prof. Curry’s assertion is incorrect?

      • Please don’t make me read @ RealClimate. Pilgrims get squished under the wheels of the machine over there.
        ======================

      • you don’t have to read RC, just go to the IPCC model archive and plot the 95% credible interval for the A1B projection for yourself, and plot the observations on the same axes. You will find that the observations are consistent with the models and hence Prof. Curry’s assertion is incorrect.

      • Mr. Marsupial,

        One of the main issues with Dr. Curry’s statement is the instrumental record and which scenario is used to determine if HI is or can be falsified. Lucia has been on this subject for over a year now and comparing the various data sets to projections, in her opinion, the data is verging on falsification of H I.

        As you know, falsifying H I with the large uncertainty is not an easy thing to do. Some say it is impossible to falsify. However, since the 0.2C per decade appears to relate to the BAU scenario, there is a possibility that that scenario is falsified.

        So do you consider it valid to falsify “a” scenario, or just the particular scenario you happen to select?

      • Policymakers don’t need weathermen to tell which way the chill blows.
        ==============================

      • It isn’t difficult at all. If the observations (within their stated uncertainty) lay outside the stated uncertainty of the projections, then that would falsify the models. Yes the credible interval is broad, but that is because there are large uncertainties involved.

        However, that is beside the point. Prof. Curry has claimed that the observations are not consistent with the IPCC projections. If you plot the projections and their uncertainty, then it clearly not the case. I really don’t understand why some can’t accept this.

      • Short answer to the question is “Yes, there is indeed modeled output by latitude that matches what is going on.”

        At least, in the general terms you are using.

        Model data is available as gridded data, which allows you to get the numbers for latitudes if you want. The group at NASA also give you all kinds of plots from model runs using “ModelE”, including plots of all kinds of data by latitude; temperature included.

        The page to start at is ModelE Climate Simulations. From there, you can get to (for example) Zonal Means vs. Time, which is what I think you want. It’s the temperature response by latitudes.

        If you want to find out more about the forcing used or other information, spend a bit of time reading the pages and references and so on at that page.

        If you hunt around the web you can find other groups with more freely available models and model information. But the NASA ModelE data is pretty comprehensive and matches closely what you ask for.

      • dm @ 9:28, it is difficult to accept because I’ve stared @ the blackboard ’til I’m blue in the face, and my fingers thrill and tremble. With facade and digits such, I wanna feel the heat. It’s sadly lacking, er, at least, I’m missin’ it now.
        ===================

      • Chris Ho,

        If I am reading the plot model correctly, 1 degree of warming has not happened in the Antarctic and the tropics appear to be projected higher than observation. The sensitivity by latitude that I calculated differs a bit from the that model.

        Now is that because that model does not consider natural variation or perhaps is the radiant physics is off a touch?

      • Mr. Marsupial said, “It isn’t difficult at all. If the observations (within their stated uncertainty) lay outside the stated uncertainty of the projections, then that would falsify the models.”

        Business as usual estimates both emissions and response. That means there are two layers of uncertainty. If you consider only the response, I would say it is falsified, barely, but falsified. Perhaps a more specific post is required because the observations agree with H II more than H I.

        By separating the scenarios and the models it would be easier to determine what is falsified. I am confident some models should be either falsified or corrected.

      • As you know, falsifying H I with the large uncertainty is not an easy thing to do. Some say it is impossible to falsify.

        I’m assuming that by ‘falsifying HI’ you mean ‘falsifying the range in the IPCC’s scenario-based projections’. It really isn’t that difficult. All that needed to happen was a ~0.2ºC drop in global temperatures since 2000 (or a ~0.8ºC increase). That hasn’t happened, ergo the IPCC range is not ‘falsified’. It’s like saying it’s impossible to falsify the theory of gravity because all this stuff keeps falling down.

        However, since the 0.2C per decade appears to relate to the BAU scenario, there is a possibility that that scenario is falsified.

        The uncertainty that Dikram is talking about is for a BAU scenario (A1B). Observations are currently within the IPCC range, ergo the range isn’t falsified.

      • Paul S said, “I’m assuming that by ‘falsifying HI’ you mean ‘falsifying the range in the IPCC’s scenario-based projections’. It really isn’t that difficult. All that needed to happen was a ~0.2ºC drop in global temperatures since 2000 (or a ~0.8ºC increase). That hasn’t happened, ergo the IPCC range is not ‘falsified’. It’s like saying it’s impossible to falsify the theory of gravity because all this stuff keeps falling down.”

        Or not rise with the projection. With current sensitivity estimate of 2C and less for a doubling, that is “likely”. So it is more like falsifying the gravitational constant because things don’t fall as a fast.

        Which, if I were in the climate modeling business, I would be considering, instead of splitting hairs.

      • Capt Dallas, the model is not a perfect match. It does show some of the variation by latitude you expect but the magnitudes may differ somewhat. There is discussions of these limits on how well the model matches distributions of change over the globe in the associated journal article, prominently linked in the pages I gave previously. Section 2 lists and discussions the known deficiencies. Read it for yourself, please.

      • You promised heat, and you persist in your promise. Now, I’ve sacrificed mightily for my belief in your promises, oh, mightily. Nobody knows the trouble I seen, trouble I seen, trouble I seen.
        ====================

      • Chris Ho,

        I thought the discussion was on whether H I will be falsified and if H II and H III might be worth consideration.

        Since the projections are based on the models simulations that indicate approximately 0.2 C per decade, the error in the models in the Antarctic and tropics appear to be higher than observation, and the trend in the tropics since 1994 is only 0.04C per decade, it appears likely that H I will be falsified. Perhaps a better look at the observations will help,

        http://redneckphysics.blogspot.com/2012/02/models-versus-observations.html

        Of course, more high northern latitude stations could be added to the surface temperature records to postpone falsification, but without adjustment I doubt it will not be falsified.

      • @Dikran marsupial Is there anybody here who can admit that when the stated uncertainty of the projection is considered Prof. Curry’s assertion is incorrect?

        Judging by the following quote, apparently there is such a person:

        @Dikran marsupial This is becuase Prof. Curry failed to consider the uncertainty around the expected trend.

        But why should such a person be believed when the rule of inference they appear to be applying would seem to be that if RealClimate doesn’t know something, therefore JC doesn’t know it either.

        Now admittedly that’s how RC prefers to reason about these things, quite understandably of course, that’s how we all reason. But where in the spectrum from logical to arrogant would you say that line of reasoning lies?

        On both sides of the climate debate, the test that people seem to be applying as to whether their reasoning is logical is whether it leads to conclusions they already held.

        In my line of work, which for the last 35 years has been logic, this is known as circular reasoning.

        My experience during that period in persuading people that they are using circular reasoning is that it is utterly impossible to do so. People have beliefs, and they simply refuse to attempt to imagine the opposite. Which is what you have to do in order to debug your reasoning.

    • I have a question.

      If the range of the error bar is 0.8 and the prediction is for 0.2, what good is the predictive quality of the model?

      • timg56, you are mixing up different things. The 0.8 error bar is not an error bar for the trend which is being predicted. Trends over two decades have errors bars much less than 0.8.

      • Chris,

        It is easy to get mixed up following the discussion. Just the discussion alone between you and Girma – it appears both of you are correct, which makes me think either you both are talking past each other about different things or the nature of the data is that it can be manipulated almost anyway you want it to.

        I guess in the end it doesn’t really matter, as I believe we are getting warmer and I’m willing to accept that anthropogenic causes can be a significant factor. I just haven’t seen anything that classifies as good science that shows it is something to be concerned about. Arguing about starting points for statistical analysis of the temperature data is nothing more than an academic exercise. It is interesting and may further our understanding, but it certainly is not a clarion call to action on the part of governments.

    • Chief Hydrologist

      so the models are right but so uncertain as to be totally useless.

      • Which prompts one to wonder exactly why they are so uncertain.

        Is it just inherent in some large scale version of Heisenberg’s Uncertainty Principle? Or because we don’t know how to writhe the code? Or some other reason?

        Because it seems to me that before we spend another cent on this endeavour we need to have a very good idea of exactly what we can achieve. And that if the answer is that the models will never be good enough to have a decent idea about future temperatures, we should defund the lot immediately and spend the money on something useful instead.

        There is absolutely no point in throwing good money after bad.

      • Chief Hydrologist

        The models are irreducibly imprecise because of sensitive dependence and structural instability arising from the intrinsic nature of the multiphasic Navier -Stokes partial differential equations – they are crazy little, type 3, deterministically chaotic bastards. And people say they can’t understand me. What the hell is the freakin’ problem with them?

  71. Just to add regarding hypothesis 1 “Challenges: convincing explanations of the warming 1910-1940, explaining the flat trend between mid 1940′s and mid 1970′s, explaining the flat trend for the past 15 years.”

    what is wrong with the standard explanations, which IIRC are “solar forcing”, “sulphate aerosols” and “ENSO”.

    • The same thing which is wrong with epicycles in the geocentric model.

    • These explanations are all very dubious. I thought solar forcing was negligible (at least that is the dogma of all the IPCC reports). Sulphate aerosols influence is essentially unknown even according to the IPCC. ENSO I thought couldn’t result in a net multi-decadal trend because of conservation of energy. We have had multiple posts from Fred on this subject. Of course, when an explanation is required, one resorts to things that are essentially unknown. This is just astrology and not science. And by the way, what caused the little ice age and the Mideval climate optimum? If the models are as good as you say, then they should be able to tell us. It seems pretty clear to me that the bulk of the evidence shows that the models are overpredicting warming, especially if you use the lower troposphere satellite data.

    • Sorry, should be “solar forcing variations are negligible compared to other forcings.”

  72. Tomas Milanovic

    Judith

    I liked much your attempt at differentiating the hypothesis used to establish a theory of climate dynamics.
    I would like to attempt to use this differentiation to identify more accurately the physical background.

    You wrote:
    I. IPCC AGW hypothesis: 20th century climate variability/change is explained by external forcing, with natural internal variability providing high frequency ‘noise’. and Hypothesis I derives from the 1D energy balance, thermodynamic view of the climate system

    The operative word is here 1D.
    To stay rigorous, Hypothesis 1 is not really that the variability = GHG signal + noise.
    The real Hypothesis 1 is that the climate system can be robustly and deterministically predicted by a 1D model.
    This Hypothesis has necessary consequences.
    – only energy balance matters (here comes the school of people saying that the system is trivially simple because it exchanges energy only by radiation)
    – only “equilibrium” matters (here comes the school of people who compare the system to a small ball slightly moved away from its equilibrium position inside a spherical bowl)
    – space doesn’t matter (this is a tautology because if a 3D system can be reduced to 1D and still predicted, then the “neglected” 2 D obviously didn’t matter)
    – from the above follows also necessarily that everything that happens in the real 3D world can only be noise (here comes the school of people who say that everything averages out)

    Interestingly you will have noticed that 99% of the comments here are resolutely 1D and many are even totally unable to understand the difference between a 3D world and a 1D model. This gives us some of the funniest coments which boil down to saying things like “What can be possibly complex about multiphasic Navier Stokes? How can that be relevant to anything?” ?

    The analogy to this schol of thinking comes immediately in mind and I am sure that you will understand what I mean because you come from fluid dynamics even if, unfortunately, it will be wasted on most commenters amateurs of the 1D hypothesis.
    2D and 3D Navier Stokes.
    Why is 2D N-S easy?
    Because the vorticity is conserved in the inviscid limit.
    Of course it is not conserved for 3D N-S and we live in a 3D world.
    So people who would only learn 2D N-S would never understand why N-S is really hard and why we can’t correctly explain things that are easy to explain in a 2D world.

    To resume the 1D climate hypothesis is per definition unable to explain anything that happens in the neglected 2 dimensions and must rely on the axiom that all these 3D phenomena do not matter. This is cannot be proven in the frame of this theory and must be postulated.

    I did not really understand Hypothesis 2. It seems to me like a curve fitting exercice where I add periodic signals which are superposed to a linear signal. The whole exercice happens still in 1D though and that’s why it would be just an avatar of the Hypothesis 1.

    Hypothesis 3.

    Climate shifts hypothesis: 20th century climate variability/change is explained by synchronized chaos arising from nonlinear oscillations of the coupled ocean/atmosphere system plus external forcing

    Here it is not really a hypothesis but a physical reality.
    I hope nobody would defend the idea that the system doesn’t obey the dynamical equations transcribing energy, momentum and mass conservation (e.g Navier Stokes &Co).
    And obviously it happens in a 3D world.
    As obviously the fields interact and are coupled in a non linear way.
    The Lyapounov coefficients are clearly >0.
    So this the only way to take the system seriously.
    Sure, it is much harder to solve than unrealistic 1D linear lodels but since when did Nature care about what was hard and what was easy to solve?
    For me this is the only serious paradigm with some physics inside and it is a disgrace that there are still people who don’t understand it.

  73. It seems, (il semble,) compared to cloud related climate shifts, l’ombre de homme n’importe:

    ‘And here face down beneath the sun
    And here upon earth’s noonward height
    To feel the always coming on
    The always rising of the night.

    To feel creep up the curving east
    The earthly chill of dusk and slow
    Upon those underlands the vast
    And ever climbing shadows grow

    And deepen on Palmyra’s street
    The wheel rut in the ruined stone
    And Lebanon fade out and Crete
    High through the clouds and overblown….’

    With “You, Andrew Marvell,” I rest my case.

  74. A question for “skeptics.”

    Seems to me that the point at which you should crow about predictions of future temperatures being wrong is the point at which any known magnitude of year-to-year fluctuation (anomalies?) would still leave the overall trend outside the projected range. (I believe that mosher has said some things along similar lines).

    In other words, if 2012 were as much warmer than 2011 as 1997 was compared to 1996, and still the overall trend would not fall into the predicted range, then there are some serious problems with the predictions. That logic could be extended to two year differences, or ten year differences, etc.

    In other words, if the previously observed degree of variability, if repeated, would not substantiate the predictions, then it would seem to me to be reasonable to assert that the predictions were in error.

    Of course, you’d also have to account for any established trend of increased year-to-year, or two-year to two-year, or decade-to-decade variability.

    Can some “skeptic” take pity on me, read what I just wrote, and clear up my silly attempt at understanding how to evaluate the validity of the IPCC’s “predictions.”

    • Of course, the 1997-1998 comparison was just an example. The point would be to use the largest magnitude of variability that has been observed for any given period of time.

    • Joshua. Youa re absolutley correct. Girma’s graph, the URL of which I have lost, makes the issue