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By William and Gavin

On Thursday March 8th, the UK TV Channel 4 aired a programme titled “The Great Global Warming Swindle”. We were hoping for important revelations and final proof that we have all been hornswoggled by the climate Illuminati, but it just repeated the usual specious claims we hear all the time. We feel swindled. Indeed we are not the only ones: Carl Wunsch (who was a surprise addition to the cast) was apparently misled into thinking this was going to be a balanced look at the issues (the producers have a history of doing this), but who found himself put into a very different context indeed [Update: a full letter from Wunsch appears as comment 109 on this post]

So what did they have to say for themselves?

CO2 doesn’t match the temperature record over the 20th C. True but not relevant, because it isn’t supposed to. The programme spent a long time agonising over what they presented as a sharp temperature fall for 4 decades from 1940 to 1980 (incidentally their graph looks rather odd and may have been carefully selected; on a more usual (and sourced!) plot the “4 decades of cooling” is rather less evident). They presented this as a major flaw in the theory, which is deeply deceptive, because as they and their interviewees must know, the 40-70 cooling type period is readily explained, in that the GCMs are quite happy to reproduce it, as largely caused by sulphate aerosols. See this for a wiki-pic, for example; or (all together now) the IPCC TAR SPM fig 4; or more up-to-date AR4 fig 4. So… they are lying to us by omission.

The troposphere should warm faster than the sfc, say the models and basic theory. As indeed it does – unless you’re wedded to the multiply-corrected Spencer+Christy version of the MSU series. Christy (naturally enough) features in this section, though he seems to have forgotten the US CCSP report, and the executive summary which he authored says Previously reported discrepancies between the amount of warming near the surface and higher in the atmosphere have been used to challenge the reliability of climate models and the reality of human induced global warming. Specifically, surface data showed substantial global-average warming, while early versions of satellite and radiosonde data showed little or no warming above the surface. This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected. New data sets have also been developed that do not show such discrepancies. See-also previous RC posts.

Temperature leads CO2 by 800 years in the ice cores. Not quite as true as they said, but basically correct; however they misinterpret it. The way they said this you would have thought that T and CO2 are anti-correlated; but if you overlay the full 400/800 kyr of ice core record, you can’t even see the lag because its so small. The correct interpretation of this is well known: that there is a T-CO2 feedback: see RC again for more.

All the previous parts of the programme were leading up to “so if it isn’t CO2, what is it?” to which their answer is “solar”. The section was curiously weak, and largely lead by pictures of people on beaches. It was somewhat surprising that they didn’t feature Svensmark at all; other stuff we’ve commented on before. Note that the graph they used as “proof” of the excellent solar-T connection turns out to have some problems: see figure 1c of Damon and Laut.

Along the way the programme ticked off most of the other obligatory skeptic talking points: even down to Medieval English vineyards and that old favourite, volcanoes emitting more CO2 than humans.

It ended with politics, with a segment blaming the lack of African development on the environmental movement. We don’t want to get into the politics, but should point out what the programme didn’t: that Kyoto exempts developing nations.

[Also: other discussion at InTheGreen, Stoat, The Guardian and
Media lens.]
[Update: What Martin Durkin really thinks!]
[Update for our german readers: A german version of the “swindle” film was shown on June 11 on German TV (RTL); here is a german commentary by stefan.]

558 Responses to “Swindled!”

  1. 401
    Nathan says:

    “…if you overlay the full 400/800 kyr of ice core record, you can’t even see the lag because its so small.”

    You may be right on the issue, but this is shoddy reasoning. Who cares whether you can see the lag on the 400-800 kyr graph? Does it disappear if you can’t see it?

    You still haven’t answered the fundamental question: If CO2 drives temperature change, why does the temperature change appear in the record before the C02 increase?

  2. 402
    Dave Rado says:

    Re. 401 This question has been exhaustively answered over and over again in the past few days, in this and in other realclimate threads. How many times do people here have to answer the same questions? See for instance here (wait for the page to fully load � it will eventually jump down to the relevant posting).

  3. 403
    Robin Levett says:

    Nathan (#401):

    An even shorter answer to your question is: No-one claims that CO2 is the only driver of temperature change.

  4. 404
    Gavin McP says:

    #399: “Regarding Chris Merchant’s reconstruction of the solar-T curve. Doesn’t the 11 point moving average which forms the first step of the analysis give you the solar cycle length (or something proportional to it) from the sunspot number?”

    From watching the presentation, the graphs look similar but not identical. Come to think of it, I don’t understand why the two graphs should look so similar – can anyone enlighten me?

  5. 405
    James says:

    Re #401: [You still haven’t answered the fundamental question: If CO2 drives temperature change, why does the temperature change appear in the record before the C02 increase?]

    Because CO2 only drives temperature change when it’s in the atmosphere. Before humans came along and started burning fossil fuels, the only way to increase the amount in the atmosphere was for something else to warm up the planet and cause CO2 to be released from warmer oceans.

  6. 406
    Barry Wells says:

    Gavin, In your article SWINDLED! you make the following observation ,’the 40-70 cooling type period is readily explained, in that the GCMs are quite happy to reproduce it, as largely caused by sulphate aerosols’. Do you know of any work / data that might have been produced which investigates any possible effects on the climate relating to the 528 atmospheric Nuclear bomb tests that took place betwen 1945 and the mid 1960’s. A time line that covers the major part of the period with a depresion of the temperature signal.

    [Response: What mechanism would you propose? My sense is that anything sensible would end up being completely negligible. – gavin]

  7. 407
    Flightless Bird says:

    I’ve been posting on a general message board (hence the silly name) trying to explain some of the arguments about global warming. I got asked about the lag between T and CO2, and after reading some (but not all, I couldn’t get onto the site because it was too busy) of the above responses, made the post below. I suppose I should have asked you gus first, but is it a corrct explanation?

    “First, it seems pretty clear that in the recent geological past that CO2 concentrations have been *lagging* temperature (T) changes by about 600-800 years. However:
    (1) This is not the primary scientific evidence for CO2 being responsible for the current warming.
    (2) It is also not inconsistent with CO2 being responsible for the current warming.

    The important point is that causation does not work in just a single direction between T and CO2, but in both directions: T has an effect on CO2, and CO2 has an effect on T. We know this from well understood physical and chemical properties that can be measured in the laboratory: as you warm up water (on a big scale â?? the oceans) it gives off the dissolved gases, so increasing T increases CO2 in the atmosphere; and CO2 molecules absorb long-wave radiation (ie heat radiation) and then re-radiate it (and in the atmosphere since half of it gets re-radiated downwards this tends to keep the earth warmer than it would otherwise be), so that more CO2 in the atmosphere tends to increase T.

    Systems in which causation works in both directions are not unfamiliar to us. Think about education and wealth: better educated people tend to end up with better jobs and as a result become wealthier; on the other hand, wealthy people are able to buy their children better education. So if causation works in both directions, what determines which will lag the other one? Imagine that we could play God and change either education or wealth levels (I donâ??t mean to cause offence, what Iâ??m simply trying to do is to imagine being able to change one of these two independently of the backwards and forwards causation between wealth and education). Say we made wealth go up and down cyclically over a period of 100 years. Itâ??s not difficult to see that weâ??d expect cyclical variation in education that lagged behind the variation in wealth. Now imagine that we make education go up and down cyclically instead: weâ??d then expect wealth to go up and down cyclically, but lag behind education. So which of the two variables leads, and which lags, depends on which is being â??externally drivenâ??.

    OK, now back to CO2 and T. Over geological time, temperature is externally driven by variations in solar heating caused by orbital variations (no, not the sunspots that the program talked about): in these long cycles, T tends to drive CO2, and CO2 lags by 600-800 years. But since the industrial revolution man has been adding huge quantities of CO2 to the atmosphere. (We know that, at the very least, because there are good records of how much coal and oil have been extracted (and subsequently burnt.) This is now acting as the dominant driver, swamping the gentle decrease over the last 8000 years in temperature that would have been expected from the stage that we are currently at in the solar heating cycle.

    This is why the fact that CO2 lags T in the recent geological past is not inconsistent with CO2 being the *cause* of the current increase in T.”

  8. 408
    Nathan says:

    #s 402 and 403:

    I do not object to the claim that C02 is a greenhouse gas and, all else being equal, more C02 will lead to warmer temperatures. That is why I prefaced my comment with “you may be right on the issue.” I object to two claims:

    1. That the importance of the 800 year gap is somehow mitigated by the fact that it isn’t obvious on a plot of poor enough resolution, which is just downright silly, and

    2. That a plot showing the correlation of temperature and C02 through geologic history constitutes *evidence* that rising C02 will in fact cause rising temperatures. Most popular presentations on global warming and not a few allegedly technical ones entirely omit the elementary point that correlation is not causation.

  9. 409
    Hank Roberts says:

    Nathan, the causation is basic physics, see the AIP history, search for “Arrhenius” — this just isn’t in doubt, even before the uncontrolled experiment by burning fossil fuels put it to experimental test.

    It’s a chicken and egg problem, you can start with either one and get more.

  10. 410
    Pete Burns says:

    Not too many decades ago I can remember reading with some alarm a full two page newspaper article by eminent scientists explaining how the world was facing an imminent ice-age. Since the place I live was under 300 feet of ice less than 10,000 years ago I thought of moving. Seems things (or funding?) has run out on that one. Anyway following “the program” I have been doing a bit of looking around regarding anthropomorphic induced climate change and would appreciate comments on the following extract from a site with it’s own opinions. Thanks in anticipation.

    “The focus solely on CO2 is fueled in part by misconceptions. It’s true that human activity produces vastly more CO2 than all other greenhouse gases put together. However, this does not mean it is responsible for most of the earth’s warming. Many other greenhouse gases trap heat far more powerfully than CO2, some of them tens of thousands of times more powerfully. When taking into account various gases’ global warming potential – defined as the amount of actual warming a gas will produce over the next one hundred years – it turns out that gases other than CO2 make up most of the global warming problem.

    …. the fact remains that sources of non-CO2 greenhouse gases are responsible for virtually all the global warming we’re seeing, and all the global warming we are going to see for the next fifty years. If we wish to curb global warming over the coming half century, we must look at strategies to address non-CO2 emissions.


    By far the most important non-CO2 greenhouse gas is methane, and the number one source of methane worldwide is animal agriculture.

    Methane is responsible for nearly as much global warming as all other non-CO2 greenhouse gases put together. Methane is 21 times more powerful a greenhouse gas than CO2. While atmospheric concentrations of CO2 have risen by about 31% since pre-industrial times, methane concentrations have more than doubled. Whereas human sources of CO2 amount to just 3% of natural emissions, human sources produce one and a half times as much methane as all natural sources. In fact, the effect of our methane emissions may be compounded as methane-induced warming in turn stimulates microbial decay of organic matter in wetlands – the primary natural source of methane.”

    [Response: I greatly doubt that you saw any such article by ’eminent scientists’ – but if you can find it, I’d be interested. It is not true that the non-CO2 gases are more important than CO2, currently they are slightly less, but the growth rate of those forcings is actually less than CO2. Methane is important, and the flattening of it’s concentrations in recent years is a small ray of sunshine in the whole situation. The statement that the non-CO2 gases are responsible for all recent climate change and for all projected growth is simply false. – gavin]

  11. 411
    Walt Bennett says:

    Re: #410,

    “I have been doing a bit of looking around regarding anthropomorphic induced climate change and would appreciate comments on the following extract from a site with it’s own opinions.”

    My comment is, there is nothing controversial there. Dr. James Hansen of NASA-GISS said the same things in 2000:

    Global Warming in the 21st Century: An Alternative Scenario

    A common view is that the current global warming rate will continue or accelerate. But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols, the positive and negative climate forcings of which are partially offsetting. The growth rate of non-CO2 GHGs has declined in the past decade. If sources of CH4 and O3 precursors were reduced in the future, the change in climate forcing by non-CO2 GHGs in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions, this reduction of non-CO2 GHGs could lead to a decline in the rate of global warming, reducing the danger of dramatic climate change. Such a focus on air pollution has practical benefits that unite the interests of developed and developing countries. However, assessment of ongoing and future climate change requires composition-specific long-term global monitoring of aerosol properties.

  12. 412
    Dan says:

    With a lot of help from, I think I was successful in convincing a group of hard conservatives that GGWS was a total propaganda piece. Intially they were convinced this was groundbreaking info. This page was exactly what I needed. Thanks guys!

  13. 413
    Hank Roberts says:

    Pete, what you quote contains statements about the different gases and what part of warming they’re responsible for that don’t sound familiar to me — where are you getting your beliefs about this?

    All need attention. You’re basically restating James Hansen’s ‘Alternative Path’ proposal, you know? This has come up before here, fairly often.

    I tried to look up your numbers and can’t find them. What’s your source?

    I found this, for example:
    “carbon dioxide emissions account for 80% of the contribution to global warming of current greenhouse gas emissions, as compared with 57% of the increase in radiative forcing for the 1980s.”

  14. 414
    Hank Roberts says:

    Pete, it appears there are only two websites where Google finds what you’re quoting.
    Do you know who these people are? You can look them up. You should, if you’re not one of them.

  15. 415
    Hank Roberts says:

    Gavin, try dropping some chunks of the quote in #410 into a search engine; this gets intriguing.

    I found bits of it attributed to James Hansen, only in the last few days (no cite) and large chunks of it posted in various supposedly animal-rights and vegetarian sites, several of them recommending the ‘Swindled’ video.

    All very recent. I didn’t get to checking who owns the various IP addresses used, but it’s most curious to see this sort of thing suddenly showing up in a lot of places all at the same time. It’s in several threads here at RC as well.

  16. 416
    Hank Roberts says:

    Okay, this really smells funny. Googling a chunk of that text quoted, I find part of it attributed (with no cite) to Dr. James Hansen, at one of these sites (flaggman.wordpress) — alongside recommendations of the Swindled film and the Friends of Science site as well.

    Other sites mention Hansen along with repetitions of the text. It’s all basically claiming Dr. Hansen doesn’t think CO2 is responsible for warming.


  17. 417
    P. Lewis says:

    Before ‘everyone’ starts using the term, can I just say that you mean anthropogenic (originated by humans) not anthropomorphic (having or representing a human form). Clouds may occasionally be anthropomorphous, as might the edges of melting glaciers I suppose, but that would be about the limit.

  18. 418
    P. Lewis says:

    You might find the national figures issued by the US DOE instructive and informative, since these are generally broken down into actual physical masses of the individual (or groups of) GHG components and in terms of CO2 equivalents.

    And bear in mind that the fate of all CH4 emissions to the atmosphere is CO2 + H2O (over about a decade, IIRC), but offhand I can’t recall whether that’s taken account of when arriving at the GWP of CH4.

    [Response: One molecule of CH4 makes one molecule of CO2, and so the concentration of methane ~1.750 ppm only makes 1.750 ppm extra CO2 when oxidised – compared to mean concentration of 380 ppm, this is trivial. – gavin]

  19. 419
    P. Lewis says:

    Re# 418 response

    Thanks for fleshing that out.

  20. 420
    Leo says:

    #417, #411

    – “can I just say that you mean anthropogenic (originated by humans) not anthropomorphic (having or representing a human form).”

    I think that’s a bit of a bold assumption. My assumption was he was being facetious.

  21. 421
    P. Lewis says:

    Well, Leo, that might be the case, but it bears stating since people do get it wrong and the uninitiated and uneducated propagate it.

    And picking up on #410 and the assertion of an imminent ice age of the 1970s:

    Not too many decades ago I can remember reading with some alarm a full two page newspaper article by eminent scientists explaining how the world was facing an imminent ice-age. Since the place I live was under 300 feet of ice less than 10,000 years ago I thought of moving. Seems things (or funding?) has run out on that one.

    one only needs to look at the RC article hereabouts somewhere on that issue and an analysis of this issue by William Connelly. It’s a fallacy. The race didn’t get underway; the starter never fired his pistol on this issue. Which, perhaps, highlights the adage that you shouldn’t get your science from newspapers.

  22. 422
    Mike Donald says:


    Any else see this? Come to think of it when I hear Durkin I think of swear words too!

    Times article 15/3/07 headed:-
    “C4â??s debate on global warming boils over”


    Two eminent British scientists who questioned the accuracy of a Channel 4 programme that claimed global warming was an unfounded conspiracy theory have received an expletive-filled tirade from the programme maker.

    In an e-mail exchange leaked to The Times, Martin Durkin, the executive producer of The Great Global Warming Swindle, responded to the concerns of Dr Armand Leroi, from Imperial College, and Simon Singh, the respected scientific author, by telling them to â??go and f*** yourselfâ??.


    The article also has some debunking of the programmes’ claims.

    Cheers and keep up the good work.


  23. 423
    Nick Gotts says:

    Re #410, #411, #414, #415, #416.

    So far as I can tell, the original source for the quote in #410 is an article on the following page:


    EarthSave Report:

    A New Global Warming Strategy:
    How Environmentalists are Overlooking Vegetarianism as the Most Effective Tool Against Climate Change in Our Lifetimes by Noam Mohr

    The full downloadable version cites the Hansen et al NASA report for which the abstact has been quoted, and a Hansen and Sato 2001 paper in PNAS: vol. 98, no. 26, 18 Dec. 2001, p. 14778-14783, content/full/98/26/14778 (which apparently caculates the net forcing from non-CO2 GHGs to be slightly greater than those from CO2 over the period 1850-2000, when indirect effects via ozone and water vapor are taken into account). It argues that because the main anthropogenic CO2 sources also produce aerosols with a net cooling effect, warming so far is almost entirely due to other GHGs (I’d say this is a misleading way of putting the state of affairs, particularly as aerosol production can be and has been reduced for good reasons without reducing CO2); and argues that reducing methane (by going vegan) is the best short-term strategy against climate change. However, it also says:

    “While CO2 may have little influence in the near-term, reductions remains critical for containing climate change in the long run. Aerosols are short-lived, settling out of the air after a few months, while CO2 continues to heat the atmosphere for decades to centuries.”

    In sum, it’s not a scientific article, and pushes a particular line for what I’d guess are primarily non-climate related motives, but I’d say it’s by no means outright ignorant or irresponsible.

  24. 424
    Scott says:

    Most people would say that the concept of global warming has put environmentalism into the big time. The green movement was not started in the seventies, rather it was returned to after years of neglect in the shadows of the industrial revolution. Its natural to be green. Environmentalism is not a political consumer driven war, its essentially respect for ones habitat.(a fundamental of survival).

    Environmental Activism that has bled into many walks of life, many age groups, many nations. So what if global warming is�nt caused by us, we may be fighting a ghost but in doing so we are relearning the respect that we lost. Not only that but as far as energy is concerned is�nt it a good thing that we diversify into renewable sources, take the dominance of these industrial behemoths away and give our communities independence and security from the whims of war lords, extremists and despotic tycoons. Our consumption of energy from its current sources is directly responsible for countless atrocities and inequalities. It is shameful to think that this fact alone, aside from global warming would not be enough cause to rework this planets energy.

    The Nasty dwindle swindle left me with this question:
    If you categorically knew that global warming was happening but it was caused by the sun, why would you make a documentary about it knowing it would have no effect other than to stifle environmental activism?

    Send your answers to channel four ratings department, its next to the big brother alter.

  25. 425
    P. Lewis says:

    Re # 422 (Mike)

    I note Durkin has apologised and is quoted as saying

    “Needless, to say, I regret the use of intemperate language. It is so unlike me. I am very eager to have all the science properly debated with scientists qualified in the right areas and have asked Channel 4 if they will stage a live debate on this subject.”

    It is not clear to me what branch of science “intemperate language” belongs in. Should be a lively debate, though … after the watershed presumably.

    His thesis seems to be that “intemperate language” is OK in private e-mails but not in those likely to be published. For one so versed in the media, this seems very naive.

  26. 426
    Hank Roberts says:

    Scott, you have that backwards — it’s certainly possible at some point that the physicists will tell us that our star is more variable than we’ve thought, or going into a more variable period, and so will be responsible for more of the change in climate over a shorter span of time — even so short as to be important in human plans.

    If we’ve learned all we can about how life and climate work, we’ll have a better chance of handling what surprises remain in the universe, and perhaps figuring out why there’s so far no sign of intelligent life (the Fermi Paradox).

    Don’t conflate ecology —- the science needed to understand what we’re doing, considering how fast humans are changing the basics of life on the planet — with ‘environmental activism’ (commercial and political activity that changes the world, for better or worse, intentionally or not).

    The biggest environmental changes are from business as usual. The conservatives — the conservationists — are making much less difference, and they’re saying don’t burn and eat it all, we might need some of the parts to keep breathing.

  27. 427
    Mike Donald says:

    About Gavin’s response:-

    From Wikipedia

    Start Wiki quote

    The second scale is global warming potential (GWP). The GWP depends on both the efficiency of the molecule as a greenhouse gas and its atmospheric lifetime. GWP is measured relative to the same mass of CO2 and evaluated for a specific timescale. Thus, if a molecule has a high GWP on a short time scale (say 20 years) but has only a short lifetime, it will have a large GWP on a 20 year scale but a small one on a 100 year scale. Conversely, if a molecule has a longer atmospheric lifetime than CO2 its GWP will increase with time.

    Carbon dioxide is defined to have a GWP of 1 over all time periods.
    Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 62 over 20 years, 23 over 100 years and 7 over 500 years.

    The decrease in GWP associated with longer times is associated with the fact that the methane is degraded to water and CO2 by chemical reactions in the atmosphere.

    End Wiki quote

    Taking a timescale of 100 years. Methane GWP of 23
    Natural CO2 was 280-300 ppm. Present 380ppm = Man-made difference 100ppm. 23 * 1.75ppm = 40 ppm. 40/100 = 40%??? or 40/380= 11% ?

    (Or 7 * 1.75/380 = 3%).

    Sorry about the back of fag packet calcs but maybe 3% might be seen as trivial but with all this talk about tipping points etc that 11% sounds like a worry.

    I await the inevitable corrections to my howlers.

    Keep up the good work.


    [Response: GWP is only useful for comparing future emissions of CH4 and other non-CO2 GHGs, it doesn’t tell you about the attribution to changes so far (there are complicated reasons why this is so for CH4). For the anthropogenic increase in CO2 (100 ppm) and the anthropogenic rise in CH4 (~1000ppm), the radiative forcings are ~1.5 W/m2 and 0.5 W/m2 respectively. Current growth rates though are strongly positive for CO2 (~2ppm/yr) and close to zero for CH4. – gavin]

  28. 428
    Hank Roberts says:

    And — for Scott — of course scientists think about what the sun may do. Sol _is_ a variable, just not a very variable variable, on the time scale we know about.

    This is fiction, and I _think_ the Apollo rocks really weren’t as described, after a later look. But it’s within the realm of possibility.

    Knowing how the world works is the secret to having a chance of outliving it:

  29. 429

    [[Sol _is_ a variable, just not a very variable variable, on the time scale we know about.]]

    I think Larry Niven is responsible for this popular myth, through his award-winning “Inconstant Moon.” For the record, the Sun is not a variable. It is a main sequence star. Variables are generally red giants; i.e., stars which have gone through the main sequence and are now rapidly changing their energy output.

  30. 430

    IMO, there is something that I find strangely hypocritical about the stance of the so-called “Right Wing” RE: “The Global Warming Issue”.

    One would think that given the current (so-called) “War on Terrorism”, since it is believed that all those petro-dollars are gleefully being directed towards nations that would enjoy nothing less than the complete and utter destruction of the west and what they refer to as “the capitalist-imperialist society,” we’d at least try to double our efforts at trying to break this “Petroleum Addiction”.

    Perhaps it’s just easier for “Big Oil” to ‘go with the flow of the status quo’ then to diversify those billions in record profits towards greener technologies, never mind the thought of striking a blow against “Extremist-Islamic Terrorism,” canceling their income…

    Are you as confused as I am?

  31. 431
    Hank Roberts says:

    Sol is a G-type — not a “Cepheid variable” — but G-types are variable in output, as people keep pointing out, and varying in different ways at different wavelengths, not all in a coordinated fashion.

    A good reminder of how tentative our knowlege is, follows a discussion of what relation studies of solar and climate might have. The studies (many mentioned here in other threads) are new and tentative science:

    “… These studies, all depending upon relationships between irradiance, sunspots and faculae derived during a single solar activity cycle, or upon the still somewhat shaky calibration between measures of solar and stellar chromospheric K-line fluxes (see Hall & Lockwood 1995), must be viewed as tentative. They also illustrate that an appeal to the behavior of solar analog stars is a natural impulse. The direct comparison of solar and stellar brightness variability has, however, been slowed by the severe demands such a comparison makes on the precision of stellar photometry…..”

    Nor is Sol a “flare star” as that term is defined astronomically of course.

    Yet Sol is capable of surprisingly large flares (as in, capable of surprising us about how big, given our very limited timeline). Google “X-class flare” for some of that.

    “The largest flare in modern times was recorded in November 2003 and was estimated to be an X-40. It, too, was on the limb of the Sun and so its full impact was not felt on Earth. That flare was part of an unprecedented series of 10 major flares within two weeks; at least one Earth-orbiting satellite was disabled and one instrument aboard a Mars-orbiting craft was knocked offline….”

    I’m just saying that knowing how nature works — both our climate system and our local star — all do fascinate scientists.

    People can put a lifetime into studying something that has only a tiny, barely measurable effect on day to day life. Sometimes, later, that proves quite useful.

    Again, solar variability right now is clearly minor as a factor in the climate change we know about. Just saying, scientists don’t ignore this kind of thing, it’s fascinating. (fairly old info)

  32. 432
    tamino says:

    The sun is not a variable star in the traditional sense. It can be called “micro-variable” because its output does vary, but only slightly (as measurements of total solar irradiance confirm), but its variability is on the order of 0.1%, or (using the usual astronomical measure of brightness) about 0.001 magnitudes. At that level, only the most sensitive photometers would be able to detect its variability. Traditionally, variable stars are those whose brightness varies by around 0.1 magnitude or more, which means that brightness variations are (sometimes only barely) perceptible to the naked eye.

    Not all variable stars are red giants. In fact there are two broad classes of variables: intrinsic and extrinsic. Intrinsic variables change brightness due to changes in the star itself; this can include such phenomena as pulsation, mass transfer, starspots, or explosions (supernovae are the brightest variables of all). Extrinsic variables don’t really vary, but they seem to due to changes in viewing conditions. The best-known extrinsic variables are eclipsing binaries, in which two (or more) stars orbit each other and we note brightness changes as they take turns eclipsing other (along our line-of-sight).

    Variable star astronomy is one of the fields in which amateur observers make a tremendously valuable contribution. Those who are interested can visit the American Association of Variable Star Observers for lots of information.

  33. 433

    tamino — right, I should have remembered things like eclipsing binaries. I just meant Niven wasn’t really accurate in calling Sol “a 4% variable star.” It isn’t.

  34. 434
    Hank Roberts says:

    CNN is carrying the Congressional hearing with Lomborg right now, the congressman is referring to the “Maulder” [sic] minimum, quoting a Dr. Hall, asking about suggestions of a possible longterm disappearance of sunspots in the near future and a longterm cooling to come, and referring to melting poles on Mars.

    “I am not a scientist” Lomborg replies … “we might be surprised in 20 years and know something else” but right now the best information we have is the IPCC.

  35. 435
    Jerry Cunningham says:

    I ‘m not a scientist , biologist or any other kind of “gist” or ” tist ” , but I wonder how the same bunch of experts that can’t tell me if it is going to rain next Tuesday can predict what the weather will be like in 50 years. Also , according to most historic data ( I don’t doubt it ONE bit , I can SEE the mountains ), the spot where I am currently sitting pecking on this keyboard was under about 500 feet of ice about ten thousand years ago. Where did the ice go ? What caused THAT global warming trend ? Please answer if you can….THANX

    [Response:Milankovitch – gavin]

  36. 436

    Many of the conversations in this particular thread have been alarming in the failure to come to terms with nomenclature. I see lots of instances of people talking past one another.

    The case of Reid vs almost everyone else is especially disconcerting. Reid is trying to explain a very rigorous body of mathematical theory that is at the core of electrical and mechanical engineering curriculum. Dismissing his comments (as Gavin does in the response to #228) greatly damages the credibility of RC and of climate science.

    The distinction of positive vs negative feedback as used in climate science is, I think, identical to the distinction between amplification and attenuation as used in engineering, and NOT identical to the distinction between positive and negative feedback as used by engineers.

    Reid claims to be among the people who have a very rich theory in which these concerns are central, and he talks the talk well enough that I am entirely convinced. To dismiss him without trying to patch together what he is actually trying to say is a very serious error both intellectually and strategically.

    RC editors have taken on a very serious mandate without pay or reward, and I join others in greatly appreciating it, but it is a mission that needs to be taken seriously. While it is surely hard to keep the conversations productive, it’s particularly unfortunate when the editorial green ink pops in and contributes to the confusion rather than allaying it.

    [Response: Michael, I appreciate your comments, but I did point Reid to an excellent explanatory text which he did not read. This stuff is not difficult, and given the constraints on our time, asking someone to read the answer to his questions is not too much to ask. -gavin]

  37. 437
    Chuck Booth says:

    Re #435

    I don’t think any climate scientist would claim to be able to predict the weather 50 years from now. You are confusing weather and climate.

  38. 438
    Dano says:

    I’ve been busy and haven’t followed RC’s threads, but MTs comment popped up and I agree with his thesis. I state, as an ecosystem guy, that ecological processes have been give short shrift in answering Reid’s questions, which should be given more prominence and reflection in the climate community. That is: gawdawful interdisciplinarity a-gaaaain. I know, I know.

    Nonetheless, I hope Reid is still lurking and reads this from an ecosystem guy: there is merit in what you say and likely biota formed the 280 ppmv CO2 limit. Biota utilized the increase and did their thing. The human organism has tilted the CO2 ppmv balance and thus we are where we are today. Oh, yes, I want you to ask me where is the empiricism that biota have been the top-down control. Please ask.



  39. 439
    Barry says:

    I would recommend reading Dr.Theodor Landscheidt’s “Solar Activity: A Dominant Factor in Climate Dynamics.” Future little ice-ages will come again and so will global warming trends.

  40. 440
    Hank Roberts says:

    > The distinction of positive vs negative feedback as used in climate science is, I think,
    > identical to the distinction between amplification and attenuation as used in engineering,
    > and NOT identical to the distinction between positive and negative feedback as used by engineers.

    Flag that somehow for inclusion in a Glossary, or a Wikipedia article, if any editor’s reading this and confirms it — that sort of thing is invaluable (was it Confucius who made rectification of names the first priority?).

    Visitors ought to be warned that climatology — like any other science — requires learning more new terms than a year or three of study of a new language, and often the same words used differently elsewhere.

    “Lessons learned” maybe. But I appreciate, just as a reader, how tired the regulars must get and how hard it often is to know where a new poster is coming from and how willing they are to read a bit and learn from what’s all around them here. Banging on the counter for fast service is hard to reward, eh?

  41. 441
    Hank Roberts says:

    Landscheidt was last famous for litigation, if I recall, not for science.

  42. 442
    Hank Roberts says:

    Oh, silly me, I forgot his astology credentials (sigh). Should’ve googled first.

  43. 443

    [[ I wonder how the same bunch of experts that can’t tell me if it is going to rain next Tuesday can predict what the weather will be like in 50 years. ]]

    There’s a difference between weather (day to day variations, which are hard to predict) and climate (regional averages over 30 years or more). We can’t predict which uranium nucleus will decay next; it’s probabilistic at the most basic level of reality. But given a lump of uranium large enough to see, we can predict with extremely good accuracy how much will be left after a given period of time.

  44. 444

    [[I would recommend reading Dr.Theodor Landscheidt’s “Solar Activity: A Dominant Factor in Climate Dynamics.” Future little ice-ages will come again and so will global warming trends. ]]

    I read it years ago, when it was posted on John Daly’s warming-denial site. It’s no more accurate now than it was then.

  45. 445
    P. Lewis says:

    Re # 443 (Mike)

    Yes, I know he hasn’t apologised for “the” programme. There’ll likely be icebergs in Hades before that happens. That wasn’t the point of my post. It was all about his “intemperate language” usage (thanks for spotting the story, btw) and the naivety of thinking (such newsworthy) e-mails would remain private. It was also about his seemingly newfound eagerness “to have all the science properly debated with scientists qualified in the right areas”, which in the context of his polemic fiction is truly laughable.

  46. 446
    Leo says:

    #447, 443&c

    But surely better to let him enter into open and free debate than it would have been to prevent him speaking in the first place. I couldn’t be further from Mike’s view that C4 should somehow be prevented from giving a voice to this sort of dissent.

    The discussions prompted by this programme, not only here but across the media and down the pub are proving to be good, fair and enlightening.

    Through openness and debate the truth will prevail. Whatever it is.

  47. 447
    P. Lewis says:

    But surely better to let him enter into open and free debate than it would have been to prevent him speaking in the first place.

    But one of the main points of this thread has been about Durkin not really entering debate (the programme was a jaundiced, polemic piece) and Mike’s Times link is about not wanting to debate (telling people to go and fornicate elsewhere).

    The discussions prompted by this programme, not only here but across the media and down the pub are proving to be good, fair and enlightening.

    That it has engendered debate on blogs such as this one might well be good, but I read the 30-odd comments after the Times article that Mike linked to, and they were largely in support of the position Durkin set forth, in spite of the actual tenor of the Times article’s anti-Durkin position that those commenters were commenting on! The general level of ignorance made for depressing reading.

    C4 is a TV company with a public service broadcast remit; in airing this WAG production, C4 has done the UK public a great disservice, especially if it has left the lasting impression that AGW is a swindle (and judging by the Times correspondence that is indeed the case).

    Even if Ofcom complaints are upheld, most of those who’ve watched Durkin’s poison will be like those commenters at the Times and will take some shifting in their erroneous views. And Durkin’s poison is now on the Web in video form to win over the uneducated and ineducable, much like the 9/11 and Diana conspiracy theory videos are by the demented conspiracy theorists that abound.

    If Durkin had wanted a proper debate about aspects of AGW, he could have built a programme around the likes of Pielke Snr, rather than around “the usual suspects”, but that would not have played along with Durkin’s preconceived notions and political outlook, it seems.

    You don’t inform and engender proper debate by publishing lies, which is what Durkin has done. Durkin is the swindler.

    Thankfully, it seems, our politicians generally have more sense, which is pretty much an unusual state of affairs in the UK (he says sarcastically).

  48. 448
    Robin Levett says:


    I don’t read Mike as wanting to stop C4 giving voice to dissent – he just wants them to stop giving a platform to dishonesty.

  49. 449
    Leo says:

    But who’s to police the difference between dissent and dishonesty? More half-knowledgeable media types? Do you really want that?

  50. 450
    Joel Shore says:

    Re #435 (Jerry Cunningham):

    (1) To understand the difference between weather and climate, consider the following point: You might not have much confidence in the weather forecast for next Tuesday…or certainly not for several months in the future. However, I assume you would believe me when I forecast that(assuming you live in the mid-latitudes of the Northern Hemisphere) the average temperature in July is highly likely to be warmer than the average temperature in April which is highly likely to be warmer than the average temperature in January (assuming you live in the mid-latitudes of the Northern Hemisphere).

    (2) In regards to ice ages: Many skeptics seem to believe that the idea that the climate has changed dramatically in the past without human intervention is strong evidence that we humans are not causing climate change now. However, this logic is faulty to the point of being essentially backwards. In fact, what the climate oscillations in the past allow us to determine is how sensitive the climate is to perturbations (measured as changes in “radiative forcings”). For example, for the rise out of the last ice age, we can estimate the forcings and the temperature change that produced them. We also know quite accurately what the radiative forcing due to a given increase in CO2 is…so we can figure out how large a perturbation we are producing on the climate system. And, the answer is that it is pretty large, e.g., a doubling of CO2 levels produces a perturbation that is around half or so of the perturbation that took us from the last ice age to the present climate! That ought to give you pause when you think of all that ice that used to be on top of your present location. (And, by the way, unless you were on the very tail end of the glacial extent, I think the thickness of ice above you was likely about 10 or 20 times as large as the 500 ft you mentioned.)

    (3) As a final point, it is worth noting that past climate changes such as the changes from ice ages to warmer interglacial periods and the reverse generally took place over fairly long periods of time (although there may have been some more abrupt climate shifts too)…e.g., the temperature generally rose about 0.1 C per century. By contrast, in the last century it rose about 0.6 or 0.7 C…and will likely rise considerably more in the current century. (The current rate of change over the past few decades corresponds to close to 2 C per century.)