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Predictable and unpredictable behaviour

Filed under: — rasmus @ 13 March 2017

Terms such as “gas skeptics” and “climate skeptics” aren’t really very descriptive, but they refer to sentiments that have something in common: unpredictable behaviour.

Statistics is remarkably predictable
The individual gas molecules are highly unpredictable, but the bulk properties of the gases are nevertheless very predictable thanks to physics. More specifically the laws of thermodynamics and the ideal gas law.

The bulk aspects of the gases are a result of the statistical properties of a vast number of particles. Statistics is surprisingly predictable even if the individual cases are not.

Just look at Las Vegas and the insurance industry which make a living on the fact that probabilities (statistics) are predictable. Even economists pin their hope on statistics, and the medical sciences would never be where they are now without the predictive power of statistics.

A “gas skeptic” would say that you cannot predict the state of the gas because the molecules are unpredictable. This is analogous to saying that climatic states cannot be predicted because the weather is unpredictable (a “climate skeptic”).

Climate is weather statistics
Climate can be viewed as weather statistics. Early climatological work was dedicated to survey of how the weather statistics varied from place to place and over the seasons.

There are clear effects of physical factors (latitude, mountains, distance to the coast) on the statistical character of the weather and the weather statistics (climate).

In other words, the statistical properties are a result of the physical processes and conditions present and are readily predicted from e.g. geographical factors, seasonal variations in the solar inclination, the atmospheric composition and the planet’s distance to the Sun.

The weather statistics (eg probabilities) are predictable in spite of the chaotic and nonlinear character of weather itself.

Common misconceptions
There are some examples where the question about predicting the exact state is mixed up with the question of predicting the statistical properties of the system, even by people with some experience in climate research.

Some of them are useful for further learning, and there is a number of them in a ‘report’ (“Climate models for the layman”) that Judith Curry has written for a British interest group that calls itself “GWPF”.

Curry’s report has also been used to back Norwegian contrarians who support the effort of a populist politician to get a seat in the parliament.

The analogy to a “gas skeptic” above illustrates why Curry’s claim is misconceived because it is false that the climate models are unfit to make predictions about the future climate just because the atmosphere behaves in a nonlinear fashion due to the Navier-Stokes equations.

The Navier-Stokes equations describe the atmospheric flow (winds), but the key equations for climate change involve the laws of thermodynamics and the way the different gases absorb different frequencies in the electromagnetic spectrum.

The most important nonlinear component in this respect include scattering processes, phase transitions, and cloud formation.

A potential feedback paradox
Curry also introduces a potential paradox in her report when she emphasises natural variations. The magnitude of natural temperature variation are regulated by feedback processes and have physical causes. The climate sensitivity also involve such feedback processes.

Any feedback process based on temperature will act on both natural and forced changes in the temperature. If such feedbacks result in pronounced natural temperature variations, they also imply that the climate sensitivity is high.

Examples of such feedbacks include increased atmospheric humidity and reduced snow/ice cover. Processes involving clouds are more uncertain, but they too are likely to be affected by temperature (convection) and act to modify the climatic response.

Natural variations may arise from both variations in the climatic state (eg ENSO, NAO, and PDO) or from external causes, such as changes in the sun and volcanic eruptions.

There are also feedbacks relevant to forced variation as well as internal variability which don’t always mean that higher amplitude natural variability necessarily indicates greater climate sensitivity.

For example, the fact that there is enhanced variability in the 3-7 year ENSO band is a result of climate dynamics (Bjerkenes feedbacks) resonating with wave propagation timescales.

Other examples include distinct oscillatory models of variability with decadal and longer timescales, related also to oceanic Rossby wave propagation and gyre spinup processes, or timescales associated with the AMOC.

It is possible to get enhanced variability on those timescales as a result of dynamical mechanisms without needing to appeal to higher climate sensitivity.

Nevertheless, the bottom line is that Curry must prove that the feedbacks involved in the natural variations are different to those affecting the climate sensitivity before she can conclude that natural variability dominates over a warming due to increasing greenhouse gases.

It’s not the sun
When Curry believes that the changes in earth’s temperature are due changes in the sun, it is important to keep in mind that the variations in the sun only affect as a small fraction of earth’s energy input. Amplifying feedback processes are needed to explain the magnitude of the observed changes.

Curry makes a point of the temperature increase before the 1940s, and that the CO2 concentrations were low then. But she seems to have forgotten that the forcing is proportional to the logarithm of the concentration: the effect of an increase is initially higher with lower concentrations.

The changes in the climate before 1940 were a result a combination of factors when there was an increase in the number of sunspots that coincided with increasing CO2-concentrations.

It is well-known that the sunspot record suggests an increase up to the 1950, but various solar indicators indicate no long-term trend in the sun since the 1950.

Only the increase in the greenhouse gases can explain a forced warming since the 1950s because no other physical forcings exhibit long-term trends since then.

Problematic statistics
Another issue is that early temperature record does not give as complete global data coverage as more recent measurements. The global temperature analysis is based on smaller sample in the early part, for which we expect to see stronger random sampling fluctuations.

This is consistent with what Figure 4 in Curry’s report shows. However, she misinterpreted this as being strong natural variability in the early part of the record.

Curry also makes the same mistake as John Christy by using the ensemble mean as a yardstick for the models (here): model evaluations must be based on the individual simulations taking into account the spread of the ensemble run.

It’s not just the temperature
The climate sensitivity is one indicator for the consequences of a global warming which only accounts for the change in temperature, but it is important not to ignore that changes in the global hydrological cycle may also have a severe impact on society.

It is possible that a weaker temperature increase is associated with a larger shift in the convective activity and more pronounced changes in the rainfall patterns (Benestad, 2016).

The comprehensive picture and consistency
I often find it useful to look at the comprehensive picture in science and look for consistencies, both when it comes to physics and the logic.

A curious twist in Curry’s report is (a) her claim that climate models have exaggerated climate sensitivity because they did not reproduce the observed warming over the 2000-2015 period and then (b) her emphasis on natural variations having scales of “weeks, years, decades, centuries and millennia”.

If the claims hypothetically were correct, then how would she know that the temperature variations over brief intervals are not just a result of the natural variations that she emphasised?

We should expect some brief periods with both rapid as well as slow warming (Easterling and Wehner, 2009), and some of the model simulations have indicated a weak warming over the same period. This is explained in the IPCC AR5 (Box 9.2).

Another question is whether the warming rate reported by the AR5 was correct, and more recent studies suggest artificially weak warming connected to changing observational networks (Karl et al, 2015). This has been discussed here. Hence, Curry’s claim about slower warming rates has lost substance.

There is a curious remark in Curry’s report about the climate models’ inability to match the phase and timing of the natural variations. Yes, it is true, but it is also a well-known fact.

The way it is stated in the report makes me think that Curry has not understood what the climate modelling community is trying to do, however. My suspicion is strengthened when she makes a point about the model simulations not including future changes in the sun and volcanic eruptions.

The elementary misconceptions revealed by Curry’s “Climate Models for the layman” surprise me. Does she really not understand the flaws presented here or is she trying to sow confusion?


  1. R.E. Benestad, "A mental picture of the greenhouse effect", Theoretical and Applied Climatology, 2016.
  2. D.R. Easterling, and M.F. Wehner, "Is the climate warming or cooling?", Geophysical Research Letters, vol. 36, 2009.
  3. T.R. Karl, A. Arguez, B. Huang, J.H. Lawrimore, J.R. McMahon, M.J. Menne, T.C. Peterson, R.S. Vose, and H. Zhang, "Possible artifacts of data biases in the recent global surface warming hiatus", Science, vol. 348, pp. 1469-1472, 2015.

137 Responses to “Predictable and unpredictable behaviour”

  1. 101
    Bryson Brown says:

    Chem Eng– “polluted with uncertainty” seems to get things wrong from the start. It’s been said before, but coin flips are “polluted with uncertainty” and despite that, we can produce very good predictions of their statistics. Since climate is a statistical characterization of weather, uncertainty is part of the package. But so long as climate is stable, we should expect the statistics to stay the same– rare hot days (hotter by 1SD/ 2SD etc.) should stay just about as rare over the years and decades.

    But when we do things like increase GHGs, which affect heat transfer back out to space and thereby increase total heat energy in the climate system (a point that clearly isn’t polluted with uncertainty) we raise a question worth exploring: What will the climate impact(s) be, i.e. how will the statistics of weather change?

    Given the limits of modelling, we can’t expect to get the one right answer. But we can explore a range of reasonable possiblities, corresponding to serious modelling efforts and supported not just by what’s known about the basic physics (that, of course, goes into all the models), but by the successes of such models in capturing known changes/ responses of the climate system (e.g. to large volcanic eruptions, slight variations in solar input across the solar cycle, etc.).

    For policy purposes, given that the models uniformly display many familiar patterns of climate behaviour, fit well with test cases like eruptions and ‘fill the gap’ exercises, and that they collectively tell us that the increase in CO2 will raise global temperatures significantly (and that with a long tail that suggests a non-negligible risk of significantly larger changes than the median), I think that’s enough. A strong policy response is justified for the same reason buying insurance is: the risk is worth mitigating, given there is, on our best evidence, a high probability of serious harm assuming BAU, and a lower but non-negligible probability of catastrophic harm. I tend to see this as pretty obvious, but some still demur (and some like to spout utter nonsense rather than acknowledge the problem). Hence the fairly widespread irritability here (I feel it too).

    Polite enough for you?

  2. 102

    ChemEng, #95–“I truly hope someone or some group can come up with something that isn’t polluted with uncertainty.”

    What a bizarre idea. Uncertainty can’t be banished; it can only be minimized. (And, of course, quantified as best as possible.) In the case of climate science that has been done–or, if you insist, ‘attempted’–by examining numerous lines of intersecting evidence: physical experiment, observation of present and past climate states, analysis, meta-analysis. There is a whole lot of consilient information that says “We have a problem.”

    Yes, some uncertainty remains. But let me share a personal anecdote that is perhaps to the point here.

    Some years ago, I found myself canoeing after dark on a Southern river, banks undercut by erosion, and featuring near-horizontal trees creating dangerous ‘strainers.’ You could hear them ahead by the sound of the current in the branches, but deciphering which side of the river they protruded from was difficult.

    After the first collision–not catastrophic, the current wasn’t fast enough for that, but still unpleasant and potentially dangerous, especially if a collision should precipitate a snoozing serpent into the canoe–I decided to take evasive action *before* becoming certain which way to go: delaying, I reasoned, would mean nearly 100% collisions, whereas prompt evasive action would, if no better than chance, at least let us avoid half of the collisions.

    Didn’t hit a tree from then on.

    Moral #1: There is such a thing as unconscious knowledge, and
    Moral #2: Certainty is not always your friend.

  3. 103
    Vendicar Decarian says:

    74 – “I haven’t the faintest idea what you are talking about”

    That is a self evident failure on your part.

    You are clueless.

  4. 104
    David says:

    This comment thread has been derailed by Flynn it seems to me. Thus, as Passey points out the important issues raised have not been addressed, particularly by the author of the post himself.

  5. 105

    CE 95: There are well known equations that describe stellar evolution… just like the gas laws! A set of equations for climate? Sorry. Not yet.

    BPL: Sorry. You’re wrong. There are. There are equations for radiative transfer, for the behavior of volatiles, for the variation of sunlight with time, orbital position, and distance, etc., etc., etc. The fact that you are not familiar with those equations doesn’t mean they aren’t there.

    CE: If you write back…. count to 10 first.

    BPL: It is tempting not to write back at all to a poster as hostile and obnoxious as you are, but although I know I can’t teach you anything, I always hope I might influence a lurker.

  6. 106

    CE 98: I don’t have an opinion one way or another about the degree to which CO2 warms the planet ON ITS OWN

    BPL: But plenty of other people do, and you’d know that if you took a look at the professional literature on the subject–which you apparently have not.

  7. 107

    BTW, there are not “well-known equations that describe stellar evolution.” There are differential equations for how certain properties might vary with either an increment in radius or in mass, and there’s no way to simply solve them across the whole problem space. You have to do it numerically, and to get it right you often have to guess and start over. In some ways, stellar evolution models are very like climate models. I know since I’ve written both.

  8. 108
    Thomas says:

    Well I’m no scientist. But neither am I a dill. That I was one a very very tiny % of students in my high school at 16 years of age using a brand new Olivetti “Programmable Computer” in 1974 should be reason enough to prove that, and given I was given corporate project management and staff training responsibility for the national roll out of a cutting edge ICL Point of sale computer system (interconnected via modem nationally to the central mainframe IBM) in the mid-1980s kinda supports my opinion too, but I digress.

    94 M. Passey says: “The scientific proposition in making a climate model is that if the input is known laws of physics, the output will describe physically reality.”

    I have no idea where Passey gets that notion from, but after looking hard into the IPCC reports and agw/cc science since the late 1990s I have never seen anyone of AGW/CC science credibility putting such a view as GCMs climate models output will describe physically reality.

    Now if an “unscientific amateur” like myself knows that, I have no idea why a fully accredited scientist or a mathematician with a degree do not. Those that say such things have no credibility in my book (your mileage may vary) no matter their claimed “credentials” may be.

    94 M. Passey also says: “Medical sciences are where they are because of the predictive value of experimentally obtained data.”

    That is only half/partially true – iow cherry-picking spin. Whilst genuine scientific rigor (usually) informs all medical research in all kinds of areas it is a well known fact of medical science that their theoretical models based on hard data research for the efficacy of “medications” does not prove 100% effective on all patients. iow their theories and the practical products are as flawed as they are successful. To deny this reality is grossly unintelligent imho.

    And so what we have here is in fact nothing more than “rhetoric” by Passey and several others pretending to be pro-science. I value all genuine science progress, however Caveat Emptor and beware of frauds and sophists too.

    I agree with Ray @100: “The reality of the crisis we face doesn’t depend on models of any real sophistication–it’s just that without such models, we are trying to land a plane on a carrier deck in fog without instruments.”

    iow a WW2 pilot may well have said: “Having instruments is far preferable to having none, even if sometimes the instruments may fail completely.”

    iow it’s about rational/best practice Risk Management in a dangerous field of action… called the world’s climate system now and into the near future.

    I agree with Dr. Gavin Schmidt: “Models are useful.”

    98 Mr. Know It All says: “One irritating thing about the so-called 97% is that they will not admit even the slightest uncertainty of their “science”.

    Look you silly little man-boy. Go read an IPCC report and any AGW/CC published paper and there in BOLD lettering and even in different colours sometimes, an intelligent and honest person will see an uncountable number of degrees / % / scales of Uncertainty being presented.

    Enough of the spreading of such Blatant LIES, Mr. KIA Child!

  9. 109
    Thomas says:

    KIA, sorry about the adhom, I take it back. It;s just that after 25 years of hearing people – especially journalists and politicians – outright lie about, misrepresent and verbal what climate scientist and their science actually does say, every now and then I spit the dummy. I am totally sick of it.

    Climate science is not selling coca-cola nor claiming the 8 out of 10 dentists recommend X brand of toothpaste, nor marketers running manipulative focus groups with voters to work out what a political party’s policies should be at the next election.

    NO. They are much better than that. Like this guy who didn’t start as a climate scientist but the climate science was eventually forced upon him due to his life’s work.

    Dr John (Charlie) Veron, the ‘Godfather of Coral’

  10. 110
    Leto says:

    That clmate models are imperfect, and that the climate is more complicated and less predictable than some other domains, including toy domains like coin tosses, is not news to anyone.

    The analogy with ideal gases merely illustrates that it is possible for extreme unpredictability at a highly zoomed-in level to coexist with much better predictability at another, higher level. Similarly, climate may be more predictable than weather despite being, in some respects, a zoomed-out view of weather. If any of you have been laboring under the assumption that climate prediction is merely long-range weather prediction, then the analogy may help you see the difference. For most of you, the difference is no doubt clear anyway. Beyond that point, the analogy is not particularly relevant, and whether the predictability of climate is high/medium/low cannot be answered by further exploration the gas analogy.

    Coming at the issue from another direction, with another analogy, climate science faces some of the same challenges as medical prognostication, which is generally very poor for individual patients, but good enough to be useful. When choosing between chemotherapy and homeopathy (or resection versus chemotherapy, and so on), we do not have the luxury of waiting for medical science to develop a perfect prognostic model before acting. It is enough know that survival is likely to be substantially improved with one course of action versus the alternative. So it is with Earth as the patient.

    Really, the important questions about climate models are:
    1) How can they be improved?
    2) Would removing or reducing CO2 effects in the models improve their performance?
    3) Would ignoring climate model outputs improve decision making?

    Much as the “skeptics” like to criticize climate models, they have done little or nothing to suggest useful improvements, have not provided an alternative, non-AGW model that performs as well as existing models (or makes physical sense), and they have not made a case that ignoring models would be anything short of breathtakingly reckless.

    And of course, residual uncertainty in the models works both ways, and may mean the dangers of AGW are worse than expected, a point that the “skeptics” conveniently overlook.

  11. 111
    Ray Ladbury says:

    Mr. KIA: ” For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?”

    My experience has been that the folks who make this comparison do so, because they know a lot more about religion than they do about science–and usually they don’t know much about religion to begin with.

    What matters is self-consistency. Scientists don’t have much doubt about AGW because it is based on well validated science of venerable vintage. If you want uncertainties, look at the journals NOW. I would note that there isn’t much uncertainty about electromagnetism, either.

  12. 112
    Vendicar Decarian says:

    Four NASA Earth science missions will get axed if the Trump administration’s 2018 federal budget request makes its way into law.

    On the chopping block are the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite; the Orbiting Carbon Observatory-3 (OCO-3) experiment; the Climate Absolute Radiance and Refractivity Observatory (CLARREO) Pathfinder; and the Deep Space Climate Observatory (DSCOVR).

    Shortly after the November 2016 election, a Trump advisor said the president intends to eliminate NASA’s climate-change research. All four of the above missions are geared at least in part toward studying climate.

  13. 113
    Vendicar Decarian says:

    Global Warming Concern at Three-Decade High in US

    Americans worrying a great deal up eight percentage points to 45%
    New high of 62% says effects of global warming are happening now
    Belief that global warming poses a serious threat stretches to 42%

  14. 114
    Chris O'Neill says:

    Mr. KIA: ” For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?”

    Wrong. Religion says “God works in mysterious ways” so doesn’t always have an explanation. Denialists like the ironically named Mr. KIA have such a talent for ignorance.

  15. 115
    Jim Eager says:

    KIA wrote: “One irritating thing about the so-called 97% is that they will not admit even the slightest uncertainty of their “science.”

    An example of an “alternative fact,” more commonly known among rational people as an outright falsehood. Knowingly or unknowingly, KIA is peddling a lie, almost certainly the latter. It would be laughable if he wasn’t so fervently sure in his conviction that it is true. KIA simply has not the faintest idea what ”error bars” are or even what “probability” is. Free clue for KIA: they are how science expresses uncertainty.

  16. 116
    Radge Havers says:

    ” For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?”

    Really? You don’t even understand the basic difference between science and religion? Holy cow.

    You shouldn’t base your beliefs and arguments on superficial impressions. In this case, it just means that the body of climate science is broader, deeper and more complicated than you know or want to know. It’s a great, big world out there, KIA, and you don’t know the half of it, or how to lay a foudation for your understanding, or even how to scratch the surface, apparently.

    Basically you are just arguing from your personal incredulity. Knock it off.

  17. 117
    dhogaza says:

    Vendicar Decarian:

    “Belief that global warming poses a serious threat stretches to 42%”

    The published summary’s a bit inaccurate in that the 42% is qualified with “in your lifetime”. Older people will be less inclined to answer this question “yes” than younger people simply because they won’t expect to live as long. The answer to the question as you (and the poll summary) states would be higher than the 42% for the question qualified with “in your lifetime”. Not sure if Gallup left that qualifier out of the summary intentionally or accidentally but it makes a difference …

  18. 118
    Jon Kirwan says:

    #98: One irritating thing about the so-called 97% is that they will not admit even the slightest uncertainty of their “science”.

    That’s incorrect on so many levels.

    (1) You don’t know what you are talking about when you write “so-called 97%”. Doran’s 2009 summary of Zimmerman’s MS thesis arrived at 97.4% and you might mean that. Anderegg, et al, 2010, also wrote in their abstract the figure of “97-98%” and you might be referring to that paper. Cook, et al, 2013, mentions the figure 97.2% and you might be referring to that paper. The point here is that I don’t believe you have read any of the source materials and you don’t have any personal idea what you are talking about when you say “so-called 97%.” Instead, you have a conflated mush in your head. That’s problem one.

    (2) Probably in part because of (1), you are just ignorantly putting words into the mouths of others when you write “will not admit even the slightest uncertainty of their ‘science'”. Not one of the papers I mentioned writes anything like that.

    The problem you have is that you are ignorant and, what’s worse, filled to the brim with hubris so you have no interest in spending the time needed to developing a nuanced, more comprehensive view.

    #98: For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?

    That’s just your ignorance and hubris, again.

    Some questions come from people who haven’t spent the personal time to become well-informed and are asking them more from a personal perspective than from an informed one. Answers to these kinds of questions, when scientists dare to attempt them, will be more of an “qualitative, explanatory nature” and will probably be more of an attempt to reflect the general agreement of informed opinion about the current state of knowledge. It may look like there is always an explanation, to those who haven’t spent the time themselves to come to an independent view. But this isn’t proof that the scientific state of affairs is anything like organized religions or personal spiritual beliefs. It’s merely an honest attempt by those better informed to provide the best answer they can and at a level that can be understood by those asking the questions.

    Some questions come from others who have taken the time to gain a relatively comprehensive view of some matter and where they are pressing harder on some remaining issues that need further examination. Or, perhaps, bringing up some new unexplored (and perhaps undiscussed, at that point in time) area that needs to be pursued. Any research is going to have some known features of uncertainty and authors will usually do their best to call these out to the front. This helps point out explicitly that the authors are aware of some remaining problems, But it’s also possible that there the authors failed to realize some other factor that might have influenced their results in an (to them) unknown way and that this new factor needs to be considered and incorporated into further research. Etc. These kinds of “insider” questions are very important and prove, in fact, that there isn’t “always an explanation” as you say, but instead quite the opposite. There are, instead, always more questions to address.

    The problem you have here is your unlimited hubris, mushy and conflated ideas about the world around you, and no desire to fix any of that about yourself. You childishly prefer, rather than to look to yourself for your problems, to instead throw mud with the hope some of it might make someone else look “dirty” in your own eyes. Some children are like that.

    The answer to any, or all, of the above is of course that you buckle down and bother to educate yourself.

    #98: And the other big problem they have is the demonizing of anyone who is skeptical.

    Scientists do have a very heated process of debate among themselves that may look to outsiders as something more than a “debate.” I don’t suppose you’ve ever been exposed to that process, but I have. I cannot tell you how much my insides were twisted up the first time I stood in front of my peers and tried to present a novel idea of mine. I was torn to shreds (my words, not theirs) so fast that my head was still spinning, ten minutes later. My idea was flawed and they saw it, almost right away and had zero inhibitions about carefully exposing and laying out all the flaws. I was standing there in front of a small group of people and had “made a fool of myself,” I felt. But you know what? Right after that debacle, with my stomach still in knots over it, I was invited to lunch to talk more about the idea. It turns out that while my idea was obviously (to them) flawed, it also carried some interesting directions to consider, too. And I had a very good time exploring ways to improve the idea, that afternoon!

    I’ve learned to crave this process. There’s no time wasted over emotions. It’s brutal, at times. Or might seem so to others. But I much, much prefer it to “glad-handing” and catering to my “feelings.” In fact, I love it. I want my ideas trashed quickly, if there is some problem to be found. It saves me time in my life. And it gives me an opportunity to test the idea out and to improve it, if possible, or to go on to something else, if not. It’s wonderful. I love it. I want it.

    But to an outsider? It might look as though my group is demonizing me, personally. When none of that is true, at all. It’s just part of a very healthy process. One is luckier to have that process and one is otherwise sadly unfortunate when that process isn’t as robust and rigorous as it might be.

    With that out of the way, there is a different process in place when scientists are addressing themselves to a lay public. I can’t imagine a scientist just going out and demonizing the average lay person. Instead, if a lay person is actually interested in their work, I more likely imagine that they would be happy to hear about it and willing to spend a little time helping anyone interested. Sure, like all of us, active scientists are busy. But they also enjoy anyone else who is actually interested in similar subjects, just like any of us would be, too. Many carpenters would love to help someone else asking questions about the craft, for example.

    But scientists themselves tend to be pretty smart people, as a rule, and know better than to go around demonizing random lay people. That’s just fuels the ignorant fires. So I’m pretty sure very few scientists go around “demonizing” anyone when it comes to their professional skill area. (Of course, scientists are also people. So I wouldn’t have any trouble with a climate scientist demonizing a politician over the war in Iraq, for example. That’s just the scientist being a political person. And they have every right to that, just as you do.)

    You are probably feeling heat from people like me, instead, who have grown tired of people who are filled with hubris and never seem to care to do so much as barely lift a personal finger to work for their opinion, but instead prefer to just lay back in a rocking chair and lazily kibitz and cause trouble where there is none.

    #98: They’ll call them all kinds of insulting names, etc. Just like the Trump bashers. They just cannot seem to communicate like adults. It’s getting old.

    I think you are communicating like a child. And it’s also getting old, to me.

    You feel you can see flaws so easily where those, those who spend their lifetimes trying to carefully and comprehensively gain a foothold on the subject, cannot themselves see. You imagine, with such incredible hubris, that you are smarter than everyone else, Not only that, but also that everyone else is so much dumber than you are, too. That you can spot the flaws without even bothering to take any effort of your own. You feel you are so smart that you don’t even need to read anything, or try any experiments, or lift so much as your pinky finger and it all just “unfolds” before you.

    You really think you are so smart as that?

    You are a child. Barely even that.

    And yes, it is getting VERY VERY OLD.

  19. 119
    Mal Adapted says:

    Know It All, soi disant:

    One irritating thing about the so-called 97% is that they will not admit even the slightest uncertainty of their “science”. For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?

    Like Ray says, our self-esteemed friend fails to distinguish between science and religion. And he overpluralizes: I’ve very seldom encountered, in refereed scientific venues, absolute certainty about anything, but I do commonly find that few religious believers will “admit even the slightest uncertainty” about their faiths.

    The key distinction IMHO is that science is a way of trying not to fool yourself (“The first principle is you must not fool yourself, and you are the easiest person to fool” -R. Feynman). Scientists rely on verification by other trained and disciplined people, their “peers”, to keep them from fooling themselves. As well, even long-established theories are modified when additional evidence or analysis are introduced, with social incentives to do so conclusively.

    By contrast, religion is a way of allowing yourself to be fooled by hope (“Now faith is the substance of things hoped for, the evidence of things not seen.” -Hebrews 11:1 KJV). Social reinforcement appears to be crucial here as well. When a counter-factual belief is the shared substance of things hoped for in a community of believers, genuine skeptics will find it impossible to dislodge by empirical argument and even dangerous to make the attempt.

    The sensitivity of the size of the consensus to both the definition of ‘expert’ and the exact wording of the question, is a clue to its conditional status. So is the fact that it isn’t claimed to be 100%. Yet whatever the precise percentages are, the consensus of working climate scientists, following exhaustive debate in appropriate scientific venues, is “solid” and “secure” regarding the following propositions:

    The globe is warming, the warming is anthropogenic, and the warmer it gets, the greater the consequences to human society and the biosphere will be.

    There isn’t much debate about it still going on in those venues, but there is honest debate about just how warm it will get how soon and just what the impacts will be, under various anthropogenic interventions or none, and it’s of course risible to imply that any genuine expert hopes for impacts more severe than projected by ‘no intervention’ scenarios.

    Honest debate must be conducted in the public arena too, where it’s currently overwhelmed by dishonest debate. What Is To Be Done?

  20. 120
    Dan says:

    re:116. it goes further than that. There is little evidence of his understanding the scientific method which everyone was taught in middle school. And yet despite that ignorance, he maintains he knows something that literally every professional climate science organization and peer-reviewed climate scientist in the world does not. It is truly that absolute height of scientific ignorance, arrogance, and intellectual laziness. No effort to learn is being made. It is simple lazily regurgitating what someone told him and what he wants to beleive, peer-review science (the way science has been conducted for hundreds of years) be damned.

  21. 121
    Leto says:

    KIA:” For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?”

    This is also what we see when the doubt is manufactured, rather than stemming from genuine, informed, skepticism. Ironically, it is also what we see when evolutionary science defends itself against creationist claptrap.

  22. 122
    Joseph Sobry says:

    It’s what you learn after you Know It All that really counts.

  23. 123
    Jim Eager says:

    When they compare climate science to religion it is a tacit admission that they have no cogent scientific argument to make. It is an admission of defeat.

  24. 124
    Nick O. says:

    Hi folks,

    Not sure if this is old news now, but I just picked this up from the NSIDC site:

    “Arctic sea ice maximum at record low for third straight year

    Arctic sea ice appears to have reached its annual maximum extent on March 7. This is the lowest maximum in the 38-year satellite record. … ”

    Presumably those who think climate models are no better than trying to feel bits of sea weed (to forecast the weather) will say that such a decline in the coverage of Arctic sea ice is just natural variation, or maybe the result of bias in the satellites and recording instruments, or even bias on the part of the scientists reporting it, or some sort of galactic dust or cosmic ray artefact, or their aunt’s favourite newt just turned bright orange, etc. etc.; anything in fact other than it being something to do with climate change caused by Human activities. Perhaps we should start a book (betting book) at Real Climate offering odds on the outlandish excuses – ‘outrageous hypotheses’ indeed – likely to be offered up as the latest explanations for Arctic and other changes? Could be quite good fun, something to amuse us all while Rome (the planet) burns …

  25. 125
    Nadya Gains-Smith says:

    I cannot express how happy I am to find this blog (and also reading the comments). I am not a scientist, but I am due to start a PhD in climate change education and communication. The purpose is to find a framework/ new way to communicate and engage people in climate change through formal education throughout the university faculties (and possibly further) . This produces a lot of challenges and needs to address a lot of issues regarding engagement. Regardless this blog has enlightened and educated me. Thanks to you all.

  26. 126
    Terry Miesle says:

    KIA:” For every question which might cast doubt on AGW, there is always an explanation. This is what we see in religion, right?”

    Maybe we seem to have an answer so quickly because we’ve heard these same arguments over and over again. You may think the arguments you’re throwing around here are original and fresh but they’re long-fermented leftovers we thought we’d thrown away a long time ago.

  27. 127
    Russell says:

    Mal protesteth undermuch.

  28. 128
    MA Rodger says:

    Nick O. @124,
    You quote the NSIDC Arctic Sea Ice News page but in recent months that page has been showing signs of less-than-rigorous reporting and their headline of March 22nd ‘Arctic sea ice maximum at record low for third straight year’ is not entirely correct. It is true that 2017 is the third straight year in which a record-breaking SIE-maximum-low was reported but as the text later reports:-

    “This year’s maximum extent is … 97,000 square kilometers (37,000 square miles) below the previous lowest maximum that occurred on February 25, 2015. This year’s maximum is 100,000 square kilometers (39,000 square miles) below the 2016 maximum, which is now third lowest. (In 2016, we reported that year’s maximum as the lowest and 2015 the second lowest. An update to the Sea Ice Index last summer has changed our numbers slightly.)”

    So last year never truly achieved the accolade ‘record-breaking SIE-maximum-low’.

  29. 129

    “…long-fermented leftovers we thought we’d thrown away a long time ago.”

    Or, “Look what the cat dragged in!” :-)

  30. 130
    Digby Scorgie says:

    Nadya Gains-Smith @125

    Another good website is But perhaps you already know about it? Skepticalscience and RealClimate complement each other.

  31. 131
    Hank Roberts says:

    A hypertext history of how scientists came to (partly) understand what people are doing to cause climate change.

    This Website created by Spencer Weart supplements his much shorter book, which tells the history of climate change research as a single story. On this Website you will find a more complete history in dozens of essays on separate topics, updated annually.

    If you want basic facts about climate change, or detailed current technical information, you might do better using the links page. But if you want to use history to really understand it all…

    The Discovery of Global Warming book cover image
    Second edition, revised
    and updated (2008)

    A GOOD PLACE TO START is the Summary of the history of climate change science.
    For a scholarly preface, look at Methodology and Sources.
    If you are somewhat familiar with the subject, you could select topics from
    the Table of Contents (site map).
    You can print out individual essays using PDF files. These files are for the January 2017 version and will not include more recent updates.

    The original website (link above) is full of relevant cross-links and updated often.

  32. 132
    Nick O. says:

    #128 MA Rodger

    Many thanks for the correction. However, I am still slightly confused; possibly there’s something I have not understood here. Is this year’s maximum the lowest in the satellite record (for the last 38 years) or not? It was that point that really caught my attention, but are they wrong?

    Perhaps I should just e-mail them direct and ask …

  33. 133
    Mal Adapted says:


    Mal protesteth undermuch.

    Doubtless that makes perfect sense to you, Russell, but I’m groping for your meaning. Perhaps you’ll unpack a little?

  34. 134
    Jon Kirwan says:

    Nick O. says: (24 Mar 2017 at 12:10 PM)

    #128 MA Rodger

    Many thanks for the correction. However, I am still slightly confused; possibly there’s something I have not understood here. Is this year’s maximum the lowest in the satellite record (for the last 38 years) or not? It was that point that really caught my attention, but are they wrong?

    Perhaps I should just e-mail them direct and ask …

    Don’t get too lost in minor details. NSIDC admits (in MA Rodger’s quote from them) that a minor adjustment caused a minor change in their counting and that because of this one year was moved up a notch and one year was moved down a notch. It’s so minor, in fact, that they are talking about only 3,000 km^2 difference between figures for the prior two years. They are essentially the same, so it really doesn’t matter which is above the other.

    Worrying which is which is entirely pointless.

    By the way, the NSIDC criteria uses a 15% threshold. If the smallest “observable” section is at least 15% covered in ice then they call it 100% and move on. If it is below 15% then they call it “ice free” and move on.

    It’s a human and rather arbitrary line, and not one formed because nature shows us a clear demarcation. Who picked the magic 15% threshold?

    Prior data was taken by DC-8 aircraft (NASA DC-8 AMMR data.) With the launch of Nimbus-7 in 1978, new data became available and there was a need to “calibrate” the datasets between each other. A paper, “Aircraft Active and Passive Microwave Validation of Sea Ice Concentration From the Defense Meteorological Satellite Program Special Sensor Microwave Imager,” D. J. Cavalieri, et. al, Dec 15, 1991, J. of Geophysical Research, did that calibration work and came up with the figure to help coordinate things.

    They needed to choose something. And they did. But it wasn’t nature with a big, huge sign pointing “HERE”. Nothing at all like the 5-6 orders of magnitude gap found regarding Pluto and the distinction of “planet” using the criteria published by Brown, et. al., for example. It is, instead, a rather arbitrary and convenient line drawn for rather ordinary, human reasons. Does nature itself cares about that magic 15% number? Almost certainly not.

    So niggling over 3,000 km^2 between two adjacent years, or worrying over rather minor quibbles/adjustments, is really without any merit. They are essentially too close to call and it doesn’t really matter which is which.

    Neither you nor MA Rodger should care in the least whether one, or the other, is ahead. It’s not seeing the forest for the trees.

    That said, 2017’s March 7th record probably is significant and worth remarking on. The difference there is on the order of 100,000 km^2 relative to both of the prior two years. And that’s probably a number worth noting.

  35. 135
    Jon Kirwan says:

    Nick O. says: (24 Mar 2017 at 12:10 PM)

    Perhaps I should just e-mail them [NSIDC] direct and ask …

    Yup. Just call them. I do that anytime I have a question. Someone is always there and always quite helpful. Or write an email, I suppose. But the phone call is probably better as you can explore thoughts with them in a faster, two-way conversation than you can in email.

    I just called them a few weeks back, in fact, earlier this month. Very helpful.

  36. 136
    MA Rodger says:

    Nick O. @132,
    The “lowest in the satellite record” call is safe.
    The NSIDC data presented at ChArctic shows the record (although you’d have to untangle the various annual traces to see it). And JAXA’s VISHOP likewise. Of course, the official line set out at the bottom of the March 22 posting at NSIDC Arctic Sea Ice News is still “Final Analysis Pending” which is understandable but in this instance the Final Analysis will be as it is today.

    My mention of “signs of less-than-rigorous reporting” @128 revolves round two incidents. A year or two back the the Arctic Sea Ice News page managed to get square miles and square kms mixed up – not much more than a typo – which resulted in the deniosphere pouncing on a big freeze-up until their error was pointed out to the world.
    More recently, the December 2016 average SIE value given in the Jan 2017 report was actually the 31st December daily SIE value. This erroneous value is used in the report to claim December 2016 as “the second lowest December extent in the satellite record.” It was actually the lowest December SIE on record and by some margin. The error, quite obvious if you examine Fig 2a showing the trace of SIE Sept-Jan, also appears in Fig 3 so it is far more than a simple typo.

    And looking now I note that the data file for December Arctic Sea Ice is also showing the wrong SIE value (although the SIA value is correct).
    So rather than “signs of less-than-rigorous reporting,” I should perhaps say that, as well as one famous instance of a typo that was corrected, there is one instance at Arctic Sea Ice News of a more persistent error which has yet to be corrected. (I’ve just e-mailed NSIDC.)

  37. 137
    Mal Adapted says:

    Russell, to be clear, I recognize the allusion, I just don’t see the connection.

  38. 138
    Russell says:

    Mal should recall Feynman’s response when I asked his his opinion of a pair of much-publicized Science lede article that appeared 1n the same issue in 1983:

    “you know, I don’t think these guys really know what they are talking about.”

    Four of the co-authors were eventually elected Presidents of the AAAS & The Planetary Society. and also wrote the subsequent Science review article reporting on further research in the field.

    Like stonewalling, sociology continues to happen.

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