Solar change and climate: an update

Chris S recently posted a lengthy comment, an extended excerpt from a recent Proceedings of the Royal Society paper. Full citation is: Solar change and climate: an update in the light of the current exceptional solar minimum
Mike Lockwood
Proc. R. Soc. A 8 February 2010 vol. 466 no. 2114 303-329

The abstract is here.

It makes for a very interesting read with lots to think about so I though I would promote it to a post of its own….

The history of science reveals a series of ‘controversies’. These often develop into a state where there is little debate within the relevant academic community (and what there is tends to be on peripheral issues), yet widespread popular debate remains. This usually occurs because the research has challenged the beliefs of a significant fraction of the population at large. The nature of the controversies, however, has changed. Where, for example, the advances made by Galileo and Darwin faced opposition because they challenged the established teachings of organized religion, climate scientists in the developed world have faced opposition from their more secular societies because they challenge beliefs that justify lifestyles and/or political allegiances (Malka et al. 2009; Nisbet 2009). But there is a crucial difference about the climate change debate compared with many of its predecessors: humankind could often afford to wait for previous controversies to abate and the main damage done was an unnecessary delay to the implementation of some of the benefits of the research. There is evidence that public opinion on climate change has changed rapidly in many countries and among many demographic groups (e.g. Staudt 2008; Sampei & Aoyagi-Usui 2009), but there is also evidence that time for effective action is extremely short (Kriegler et al. 2009; Vaughan et al. 2009).

There is a third new dimension to the public debate about anthropogenic climate change–the Internet. Georg Christoph Lichtenberg (1742-1799) was the first professor of experimental physics in Germany. He was, himself, no stranger to controversy and often satirized the misuse of science. His notebooks from the second half of the eighteenth century are full of comments of remarkable relevance to the role that the Internet has played in the climate science debate. For example, he wrote ‘the most dangerous untruths are truths slightly distorted’ and ‘blind unbelief in one thing springs from blind belief in another’ (Katritzky & Lichtenberg 1984). The Internet has played a useful role in conveying some of the understanding, images and data that lead climate scientists to their conclusions. However, it has also become a haven for un-refereed pseudo-science with dangerously incorrect inference. It has served to give the false impression that there is a serious, widespread academic debate on the basic nature of climate change. The most popular argument runs like this: ‘The Sun drives Earth’s climate system. Therefore changes in the Sun must drive changes in Earth’s climate system’. The first sentence is, of course, absolutely correct; but understanding why the second sentence does not follow from the first requires scientific training and study. The urgency of the need to resolve this distinction between academic and popular understanding places scientists in a dilemma. By trying to find easy-to-understand yet irrefutable ways to demonstrate the fallacy of the above argument (and others that are more intricately constructed but no less misleading), one risks appearing to give scientific credibility and exposure to ideas of no scientific merit.

Scafetta & West (2007) and Scafetta (2009) have proposed that the use of a single response time is not adequate and the climate system has a relative rapid response of approximately 1 year and second of about a decade. Using a combination of the two, they then deduce from a multivariate fit that 65 per cent of the GMAST rise can be attributed to TSI change. Section 10 considers the energetic implications of this. Neither Lockwood (2008) nor Scafetta (2009) quotes the statistical significance of their best multivariate fits, but Lockwood (2008) did compare the 2σ deviations from the best fit for GHG and solar forcings. There are a number of complications with this kind of fit; for example, unknown inter-correlations between the inputs can influence the results. In evaluating the significance of any correlation derived one must allow for the degrees of freedom in the fit. Lockwood (2008) used seven fit parameters (a weighting factor for each of four inputs plus a lag for each except for the GHG forcing as it was taken to vary linearly with time). The formulation of Scafetta (2009) would, to be completely general, require 16 fit parameters (two lags for each of four inputs, which should all be treated in the same way, with a weighting function for each input/lag pairing). The significance of any such multivariate fit is dramatically reduced (especially when the effect of the autocorrelation of each sequence in reducing the effective number of independent samples is also considered). Further comments have been made by Benestad & Schmidt (2009). One key factor to note is the importance to the analysis of Scafetta (2009) of using the ACRIM TSI composite, on the grounds of the analysis of Scafetta & Willson (2009), but as discussed in §5, the justification for this is based on the application of an entirely inappropriate TSI reconstruction. The reason that this matters is that the PMOD composite shows that the mean TSI has fallen since 1985 (Lockwood & Fröhlich 2007), so that even the decadal scale lag proposed by Scafetta (2009) cannot explain the fact that temperatures rose until 1998 unless the ACRIM composite is used. The ACRIM TSI composite is the only one that shows a long-term peak in 1992 (see figure 4 and Lockwood & Fröhlich 2008), which would allow the long time-scale response proposed to match the apparent plateau in the HadCRUT3v GMAST data.

Just how poor and ill-informed some of the debate appearing on the Internet can become is illustrated by recurrent reports that global temperature rise is associated with changes in the corpuscular emissions of the Sun. The total energy input from the thermal solar wind plus suprathermal solar particles into the atmosphere and inner magnetosphere (some of the latter may be deposited in the upper atmosphere at a later time) is of the order of 1013 W or, per unit surface area of the Earth, 0.02 W m−2. Even if we take the extreme case that this input was entirely absent during the MM (known not to be the case), we would require an amplification by a factor exceeding 250. Furthermore, this very little energy is deposited in the upper atmosphere (the thermosphere) and there is no known viable mechanism in the published literature that will allow it to influence the global troposphere, let alone with this huge amplification factor. It is true that the history of solar-terrestrial physics shows that one cannot use the absence of a known mechanism as more than an indication: Lord Kelvin famously dismissed the growing evidence for solar influence on the geomagnetic field as ‘mere coincidence’, using an argument based on magnitudes (Kelvin 1893). The argument turned out to be wrong because it did not allow for the existence of the solar wind (which was not suggested until 1901 by George Fitzgerald). However, that situation is not at all analogous to the present situation concerning climate change. Lord Kelvin was not proposing an alternative explanation and he was quite right to point out that chance agreements do occur in datasets of limited duration (but wrong to dismiss the possibility that it was real). In the case of climate change, there is no doubt that global mean temperatures have risen, so that the effect is known to be real. Furthermore, there is a viable explanation of that effect, given that the amplification of radiative forcing by trace GHG increases by a factor of about 2 is reproduced by global coupled ocean-atmosphere models. What is alarming is that in the face of this strong scientific evidence, some Internet sources with otherwise good reputations for accurate reporting can still give credence to ideas that are of no scientific merit. These are then readily relayed by other irresponsible parts of the media, and the public gain a fully incorrect impression of the status of the scientific debate.

It is important not to make the mistake made by Lord Kelvin and argue that there can be no influence of solar variability on climate: indeed, its study is of scientific interest and may well further our understanding of climate behaviour. However, the popular idea (at least on the Internet and in some parts of the media) that solar changes are some kind of alternative to GHG forcing in explaining the rise in surface temperatures has no credibility with almost all climate scientists.


26 thoughts on “Solar change and climate: an update

  1. In the semi-popular debate, we hear that solar variation had more of an influence on climate earlier in the 20th century. This seems to be at odds with some of the statements above, that;

    The total energy input from the thermal solar wind plus suprathermal solar particles into the atmosphere and inner magnetosphere… is of the order of 1013 W or, per unit surface area of the Earth, 0.02 W m−2. Even if we take the extreme case that this input was entirely absent during the MM (known not to be the case), we would require an amplification by a factor exceeding 250. Furthermore, this very little energy is deposited in the upper atmosphere (the thermosphere) and there is no known viable mechanism in the published literature that will allow it to influence the global troposphere, let alone with this huge amplification factor.

    That reads very much like “solar variation has virtually no effect on climate.”

    Your moderately well-informed ‘skeptic’ will point out the relatively quick global warming 1910 – 1940, and ask why the rate of change is comparable to the last 30 years, when the CO2 emission was significantly smaller. Mainstreamers will advise that solar (and possibly volcanic) influences contributed. (The same to and fro accompanies to 1860 – 1880 warming meme, with the caveat that data is sparser in the early instrumental record)

    Perhaps this would be a non-issue for the better-informed target audience – earth scientists – but there is a potential irony here, where the paper is concerned with misconceptions and misunderstandings in the popularised discussion.


  2. I suspect the excerpt you quote is speaking primarily to the sunspot cycle. The IPCC cites research that does attribute as much as 30% (IIRC) of early 20th century warming to changes in irradiance. I think this is different from energy input from the thermal solar wind plus suprathermal solar particles


  3. Isn’t part of the problem that we haven’t had high precision measurements of TSI for long enough? We can use proxies such as sunspot numbers, which probably cover decadal variation due to the solar magnetic cycle, but how do we rule out centennial scale variation in TSI? I think solar/stellar modeling doesn’t show such variations, but if you are trying to convince someone who is suscipicious of computer modeling, how do you proceed?


  4. “The nature of the controversies, however, has changed. Where, for example, the advances made by Galileo and Darwin faced opposition because they challenged the established teachings of organized religion, climate scientists in the developed world have faced opposition from their more secular societies because they challenge beliefs that justify lifestyles and/or political allegiances ”

    Fundamental flaw right there.
    The Global Warming mantra, led by Al Gore et. al. (not even a scientist but a politician) is a religion, and a virulent and violent one at that.
    It does exactly the same to those proposing debate and attempting to show us reality (rather than the religious dogma that all change to the climate is not just bad but is caused by human action, that in fact the climate on this dirtball had been unchanging until the 1980s, a known fallacy) as did those who tried to stifle Galileo.
    They even attempt to install kangaroo courts to convict all those who dare oppose their unfounded claims as “enemies of the planet” and either lock them up in prisons or execute them for “crimes against humanity”.
    The medieval inquisition in Europe would be proud of them.


  5. wow – JT Wenting is a moron!!! (Troll??)

    Al Gore does NOT lead the climate change ‘religion’, and it is not even a religion. Climate change is based on evidence, science and facts, unlike religion and denialism, which is based on dogma and opinion.

    Maybe JT can demonstrate just how ‘scientific’ he is by showing us the evidence for these kangaroo courts and executions (but I think we will be waiting a long time).


  6. I’d recommend people track down the full paper, there’s much more to it than the extracts above. I would like to note that the reason I found it is that it is the sole paper in ISI Web of Science that references Scafetta 2009 (this in itself is unsurprising, it takes a while for papers to build up citatitons – the Scafetta & West (2007) paper referenced has 15 cites).

    In response to barry: “That reads very much like “solar variation has virtually no effect on climate.””.
    I’m not sure if you read the last paragraph quoted – the one that starts “It is important not to make the mistake made by Lord Kelvin and argue that there can be no influence of solar variability on climate”

    Omega Centauri: There is a paragraph in Lockwood that goes some way towards answering your question:

    “Section 5 discusses the solar cycle variation in TSI: its peak-to-peak amplitude is 1.37 W m−2, which, in the absence of any amplification mechanism, corresponds to a radiative forcing change of 0.24 W m−2 (for A=0.3). This is less than 5 per cent of the required total change in the radiative forcing since pre-industrial times derived above (ΔG=5.15 W m−2). To explain the observed GMAST rise since 1700 would require a change in TSI of 29.1 W m−2. Detection–attribution studies using climate models have found a feedback amplification of the input centennial TSI variation by a factor of βS≈3 (e.g. Stott et al. 2003; Ingram 2006), which would reduce the required TSI change to near 10 W m−2. However, one should note that some of this amplification may be unreal and due to a metrology factor (discussed in §9), which has been reported as exaggerating the downward drift in GMAST in the middle of the twentieth century. The inferred βS factor is particularly sensitive to this because the mid-century downward drift is partly explained by the solar forcing variation. Note that if the mean effective temperature of the solar surface has remained constant (and with βS=1), the simplified equation (2.1) shows that the solar radius R⊙ would have to have been 1.1 per cent smaller a century ago than it is today to supply the required radiative forcing change.”

    The equation 2.1 is not a computer model (unfortunately I can’t reproduce it here), however it is a model. It could be argued that those who are “suscipicious of computer modeling” are de facto unlikely to be convinced by anything in modern science.


  7. For those interested in possible related “amplification” effects, see here, for one >

    [mandas, that would be just for those that are curious, no sneering, please. CERN, the European Organization for Nuclear Research in Geneva, is preparing comprehensive verification, and while this is a hopelessly laughable organization, please indulge me here, you know, for those that are curious, thanks.]


  8. The “global warming is a religion” ad hominem is the last card those in denial of physical reality have to play, to be used when they have absolutely nothing of scientific merit to argue from.

    Having used it, JT Wenting now has no where to go but away.


  9. PaulinMI

    Au contraire… I am a very curious person and I usually read all the links that people provide. But I then usually do some additional research to find out more information about the papers etc, such as who wrote it and why, what the background to the paper is, what do others think about it, has there been any confirming work, etc. You know – science!! And I really wish that a few others would take this really simple concept and apply it before posting stuff here.

    We have been over the issue of cosmic rays before, and I am at a loss to understand why it has come up again. On page 11 of the CERN paper (see – I have read it), the authors make this statement:

    “…..But how could cosmic rays affect the Earth’s weather? The energy deposited by cosmic rays is only a few parts per billion compared with the incident solar energy, so a strong amplifying mechanism would be necessary. The breakthrough was made by Svensmark and Friis-Christensen in 1997 [1] who discovered an unexpected correlation between global cloud cover and the incident cosmic ray intensity….”

    They are referring to this paper here:

    However, the ‘correlation’ between cloud cover and cosmic ray intensity was unexpected because it simply did not exist. There have been a number of studies done since Svensmark and Friis-Christensen in an attempt to replicate their work (ie the scientific method). Unfortunately, and purported correlation was shown to be extremely weak, relied heavily on manipulating the data, and disappeared altogether in the late 90s. Here are just a few papers for you to have a look at:

    So thanks for the information. But if I could suggest you do a little follow on reading on the subject before linking to a paper.


  10. Re: Svensmark

    Lockwood doesn’t touch on Svensmark & Friis-Christiansen but he does spend a paragraph on Svensmark H., Bondo T., Svensmark J.(2009) Cosmic ray decreases affect atmospheric aerosols and clouds. Geophys. Res. Lett 36:L15101

    “Svensmark et al. (2009) have recently published a superposed-epoch study reporting large (up to 7%) global cloud cover decreases, as detected by a number of satellites, following Forbush decreases in GCR fluxes. The difficulty with this kind of study is that there are very few large Forbush decreases when satellite cloud data are available, so results tend to be dominated by a single event. This possibility is increased because the authors reduce the set of events to those common to all the available satellite cloud datasets used. The cloud response peaks 7 days after the GCR decrease, which is a not an expected delay. In the study of Kristjánsson et al. (2008), the number of samples was increased by taking a lower threshold cosmic ray decrease to define events. In addition to cloud cover, they studied cloud droplet size, cloud water content and cloud optical depth—all from the MODIS satellite dataset. The satellite data were divided into six regions, all of which showed a negative correlation between GCR fluxes and both cloud droplet size and cloud optical depth, but only one of which was statistically significant. For cloud cover and liquid water path, the correlations with GCR were weaker, with large variations in the behaviours between the different regions. Correlation coefficients were improved when only the six largest events were included, with 16 of the set of 24 correlations (four for each geographical region) showing the sense expected by the hypothesis that GCRs help to seed clouds, but unlike the Svensmark et al. (2009) survey, correlations were not improved by introducing a lag. Sloan & Wolfendale (2008) also found that the correlations had no statistical significance, and Erlykin et al. (2009b) divided clouds into two major types and still found that the data gave no support to the contention that there is a large-scale causative cosmic ray cloud correlation, even for the parts of the world where correlations have previously been reported.”

    Kristjánsson J. E., Stjern C. W., Stordal F., Fjoéraa A. M., Myhre G., Jónasson K.(2008) Cosmic rays, cloud condensation nuclei and clouds—a reassessment using MODIS data. Atmos. Chem. Phys. 8:7373–7387.

    Sloan T., Wolfendale A. W.(2008) Testing the proposed causal link between cosmic rays and cloud cover. Environ. Res. Lett 3:024001 (doi:10.1088/1748-9326/3/2/024001).

    Erlykin A. D., Sloan T., Wolfendale A. W.(2009b) The search for cosmic ray effects on clouds. J. Atmos. Sol.-Terr. Phys. 71:955–958, (doi:10.1016/j.jastp.2009.03.019).


  11. mandas, thanks for the suitable response.
    I am not a science researcher, nor do I have the time to be, but I am curious, so your added perspective was appreciated. I assume then, the proposed study at CERN will fail and I’ll be waiting to see the results.
    (but does seem odd they would spend that kind of money when they already know the outcome, doesn’t it?)


  12. PaulinMi the CERN experiment is no more than a hugely expensive repeat of the work done by Charlie Wilson 100 years ago. He built a “cloud chamber” and showed that ionizing radiation did indeed cause nucleation of water droplets in a saturated atmosphere.

    The big problem with the GCR hypothesis is not that they do or do not cause clouds but that there is no correlation with GCR flux and either cloud cover or temperature.

    So no, GCR’s are not responsible for GW.


  13. PaulinMI

    I appreciate that you and a lot of others may not be scientists, and may either be unfamiliar with scientific research or may simply not have a lot of time available to look up and read papers etc.

    However, most people here (yourself included) do seem to have the ability to find papers that they think demonstrates some sort of flaw in the science of global climate change. I suspect this is because you regularly read denialist (sorry – sceptical) blogs, and they have opinion pieces about relevant papers which you then link to here.

    This suggests that most people do have some time available, but it is spent reading blogs etc which have opinions which confirm their world view. Nothing wrong with that per se – most people do it – except it means you get a very narrow perspective on the issue. But it isn’t hard or time consuming to get an opposite opinion on just about every single topic in this debate – all you have to do is google it, and if the paper is opposed to climate change you will find a miriad of bloggers who will be discussing the issue already. It only took me 15 minutes or so to find those papers on cosmic rays and skim through them.

    I realise that science can be hard (it can be hard for those of us who do have science training – especially outside our fields of expertise), so it is an acceptable start to read opinion pieces. But opinion pieces are no substitute for evidence. You should always do a modicum of follow up as I have suggested before – you may well find that the piece you think has a telling point to make has already been discredited, and by linking to it you would just be making yourself look uninformed.

    In any case, research can be fun. You find out a lot of information and become more educated in the process. And sometimes you stumble across gems that really make your day or help you out in unexpected ways.


  14. Yep that was me Matt, had a bad trip from some magic mushies i found in the forest that i washed down with some Irish wisky (not a Bundaberg rum man).

    What do you call it when you write shit down when possessed but cant remember doing it? Thats what it looks like to me anyway.


  15. mandas,
    fair points. I’ll give it a whirl next time.

    And, for the record – (Skip, here it is, again)
    1] the world is warming, the records prove that (I think droyspencer had something to do with the satellite records)
    2] it doesn’t matter if it’s exceptional or not, because what is important is where it stops (or won’t stop)
    3] CO2 is a responsible party
    4] in my view, what is uncertain, is the amount of amplification (+ or -) from other factors. Self regulating or run-away.
    5] knowing how much impact of the total (temp rise) from 3] and 4] will allow predicting how much relief can be had from zero CO2 and future CO2 capture and if it has value.

    6] the clean energy issue is two sided, zero CO2 and politically stable sources.


  16. PaulinMI: “4] in my view, what is uncertain, is the amount of amplification (+ or -) from other factors. Self regulating or run-away.”

    The “run-away” bit is a straw-man. A converging series of amplifying feedbacks will by definition be self-limiting and can not produce a “run-away,” as demonstrated by the paleohistory of earth. Still, that paleohistory demonstrates that even a self-limiting array of diminishing feedbacks is able to produce temperatures much higher than those projected from fossil fuel combustion, despite natural negative or damping feedbacks. (End-Permian and PETM)

    At the same time, amplifying negative feedbacks were equally able to produce a state cold enough that it took millions of years of CO2 accumulation from volcanic sources and arrested silicate weathering to reverse. (Snowball Earth)

    In short, earth’s paleohistory demonstrates that the limits of the natural range of earth’s climate system encompass two distinctly different states capable of eliminating most forms of life on the planet without human interference.


  17. Well, Jim, ok.
    “Run-away” in my mind was to be taken as the commonly used “tipping point” reference, when I guess, all this frozen methane and CO2 breaks free in some unstoppable manner. If I have in any way misrepresented this I am sure I will be shortly corrected. But you get my point.


  18. PaulinMI

    There is a difference between ‘runaway’ and ‘tipping point’.

    Runaway essentially means (and I am simplifying here) that the feedback mechanisms are mostly positive, so as the earth heats up more of the positive feedbacks occur, resulting in more heating, resulting in more feedbacks, … more heat, …etc. However, no-one is predicting that this will occur, but there is likely to be an element of a limited positive feedback mechanism with the release of frozen methane etc as you suggested.

    On the other hand, a ‘tipping point’ is reached when the change to the climate reaches a critical juncture, and ‘tips over’ into a different stable state based on the new conditions. In essence, the climate is generally fairly stable under the current atmospheric and solar (etc) conditions. If we continue to release GHG, then the climate could ‘jump’ rapidly to a new stable state – one which is different to our current experiences. ‘Rapid’ is a relative term and does not mean you wake up one morning and find the climate is different, it may take years or decades to occur, but once the tipping point is reached it is difficult if not impossible to stop or reverse the change.

    There have been a number of ‘tipping points’ predicted for CO2 concentrations – and you can do a little research on them if you like. This paper talks about a tipping point of 450 ppm for ocean acidification, but it is just one example you can have a look at:


  19. A colleague of mine ask me to look at Scarfetta and West paper where they fit global temp to insolation, then look at the coefficient of insolation and argue the effect of insolation is much larger than what climate modelers use in their models. This deduction is incorrect; their timeseries model fits _only_ insolation, and ignores all other factors. A least squares fit will always make the coefficient as large as possible to explain as much variance as possible. Even if this is physically impossible. The correct way to determine the effect of insolation is to understand the physics, which is what climate modelers do.


  20. I’m not a scientist, so I may have this wrong, but my perception is that science is very confident about the magnitude of changes in greenhouse gases in the atmosphere, and very confident about the resultant forcing – it’s simply not credible that we could increase atmospheric CO2 (for example) without causing the forcing associated with that increase, as this is just basic physics.

    Therefore, any study which attempted to show that the warming of recent decades was simply due to some natural phenomenon (e.g. “it’s the sun”) would have to also explain what happened to the anthropogenic radiative forcing which we know must exist. It would be absurd to claim it doesn’t exist – they would have to show that it was counteracted by yet another natural phenomenon which somehow neutralised its effects. Otherwise, you would have the effects of the solar variability/whatever plus the anthropogenic forcing and would expect to see even more warming than we actually have.

    To put it another way: The global warming seen over the last few decades is consistent with what we expect to see from the anthropogenic forcings that we know exist. Therefore, you can’t argue for there being a large natural positive forcing from the sun or anything else without also arguing that there is a natural negative forcing of the same magnitude to counteract the positive one, thus leaving only the anthropogenic warming (which is the same as saying that anthropogenic forcing is causing the warming anyway). Otherwise, you have to resort to denying the basic physics of greenhouse gases, which is a nonsense since it can be proven in simple laboratory experiments.

    Does this make sense?


  21. Icarus,

    No you don’t have it wrong and yes it makes sense.

    I think you are confused though. You seem to think that denialist are required to make sense. That simply is not their agenda, which is to throw up as many red herrings, misdirections, pseudo sciences, fabrications and outright lies as possible, and hope that the ignorant general public accept them. They don’t debate the real science – because they can’t. But maybe its cosmic rays, or an alignment of the planets (yes – both of these have been thrown up as explanations). Maybe its the measuring stations are in the wrong places. And maybe Arctic ice is not diminishing. Maybe glaciers aren’t retreating. Maybe natural phenomenon are not changing. Maybe the scientists calculations are all wrong and a British inbred knows the real truth. Maybe its all a huge conspiracy to introduce a socialist world government. Or maybe the climate IS changing but it is due to some undefined natural cause, which is good because the world is too cold anyway and CO2 is a valuable plant food. Maybe… Maybe… Maybe….

    Or maybe climate change is real, and that it is due to anthropogenic causes. And maybe the people who have been studying and researching it for decades actually know what they are talking about, and can recognise something when it stares them in the face. And maybe we should stop arguing about whether it is happening, and start arguing about what we are going to do about it and when.


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