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  1. Gavin, you write :
    “they put out a press release for the world’s newspapers explaining that this result implied that all past climate changes were now understood and all future climate changes could be predicted simply from a knowledge of the intensity of these ‘cosmic rays’….”

    But I just read in the press release :
    “Hence, variations in cloud cover caused by cosmic rays can change the surface temperature. The existence of such a cosmic connection to Earth’s climate might thus help to explain past and present variations in Earth’s climate.
    Interestingly, during the 20th Century, the Sun’s magnetic field which shields Earth from cosmic rays more than doubled, thereby reducing the average influx of cosmic rays. The resulting reduction in cloudiness, especially of low-altitude clouds, may be a significant factor in the global warming Earth has undergone during the last century.”

    So, the press release in itself only suggests, with conditionnal (“may”, “can”, “might”), that variations of low-cloud nebulosity linked to cosmic rays are to be considered for a better estimate of mean global temperature’s trend.

    [Response: a) there is no trend in cosmic rays and so it's explanative power for the trend is zero. b) read the rest of the material.... It gets worse. - gavin]

    Comment by muller.charles — 16 Oct 2006 @ 8:57 AM

  2. Well, I don’t exactly know that it is quibbling to say that a paper which attempts to reproduce tropospheric conditions and thus seeks to derive it importance from that, mimics those in the Venutian stratosphere. However, fairly high up in the post I did put this update the next day:

    UPDATE: It occured to the old hare that he needs to use a hammer.

    * Everyone accepts that cosmic rays are the principal source of ions in the lower atmosphere. The ion density is around 1000/cm3.
    * Everyone accepts that there will be nucleation around the ions because of electrostatic forces

    The Svensmark et al. paper simply restated the obvious. But the real questions are:

    * Is the availability of ions the limiting factor in forming cloud condensation nuclei or is the availability of other species limiting.
    * Are there other ways of forming cloud condensation nuclei (CCN) besides around ions and if so (it is so) what is the relative importance of each type of CCN and what are the characteristics of the CCNs.

    And, I think the figure at the end from a Mexico study pretty well shows that under normal conditions SO2 is limiting for forming small aerosols.

    I think it is reasonable to assume that these particles can grow to become CCNs.

    Finally, the obsessions that one has determine the information available to you and then the direction from which you attack a problem. Our two comments illustrate that, but also raise the question of who were the referees?

    Comment by Eli Rabett — 16 Oct 2006 @ 10:49 AM

  3. OK for the rest of the material, there are some more… abrupt assertions :D

    CR is a quite complex matter and I’ve no particular competence for a personal evaluation of the researchers’ conclusions in this field. I know that Usoskin et al. have recently suggested a latitudinal dependence of nebulosity-CR relationship, with strongest correlations observed over 20-55 °S and 10-70 °N. I guess that cosmic ray intensity could varies over the globe in relation to geomagnetic field. Any opinion about that ? Is the decreasing CR trend of your figure based on one neutron monitor or on a composite index ?

    [Response: That is one neutron monitor (CLIMAX), but correlations to others are very high. One expects solar modulation of cosmic rays to have a latitudinal distribution (higher near the poles than the equator) due to the geomagnetic sheilding, but these are also the arreas where one expects greater solar responses in any case (i.e. through TSI/ozone feedbacks on the annular modes for instance) and so doesn't implicate cosmic ray effects specifically. - gavin]

    Comment by muller.charles — 16 Oct 2006 @ 10:49 AM

  4. Quite a sound demolishing of the claims in the press release. I especially liked the link to Rabett Run ( ), where Eli points out that the SO2 level used in their study, 5000 ppb, is 167 times as high as a very smoggy day in Mexico City, at 30 ppb. Eli also references a graph ( ) that shows an excellent correlation between spiking SO2 levels and spiking >10 nm aerosol particles. As you pointed out before, Gavin, “why are they spending millions on this study again?” It’s as if I “discovered” that there’s a strong correlation between fires in houses and child deaths, and then claimed that this burning process is primarily responsible for all non-disease deaths in children (Fires are 5% of deaths 0-17 in the US: #1 is motor vehicle accidents, 45%; #2 is firearms, 14%; #3 is suffocation, 12%). Sheesh.

    Comment by Steffen Christensen — 16 Oct 2006 @ 10:57 AM

  5. Real Climate should not restrict any postings on the solar or any other issue it deems important. Your track record is solid on this. If the topic is misused, we need to understand the (RC) logic. I’m very impressed by this site but I sometimes long for more explanations, at least for those of us that last attended science class 40 years ago. Think of how many more people you could reach. Keep it up.

    Comment by Normand Chevrier — 16 Oct 2006 @ 12:49 PM

  6. re: 3.

    A “latitudinal dependence … with strongest correlations … 10-70 °N” may help explain the warm dust bowl years of the 1930s and contributions to higher global temperature 1930s-1940s.

    Comment by Pat Neuman — 16 Oct 2006 @ 1:08 PM

  7. Hi,
    I’ve enjoyed your blog for quite a while and now that you are commenting on a paper that I co-authored (I’m a PhD-student on the project) I felt that it was time to contribute actively.

    First I’d like to comment on a misconception concerning our gas concentrations:
    The SO2-bottle that we used was indeed a 5 ppm mixture, but it was diluted heavily with a resulting concentration of around 80-230 ppt in the chamber. The ozone concentration of about 25 ppb fits with the 20-40 ppb for marine environments given in the book by Seinfeld and Pandis (Atmospheric Chemistry and Physics p. 310).

    Regarding the missing steps:
    Step 1+2 (impact on CCN): I agree that this absolutely needs to be investigated further. Our proposed mechanism could produce quite a lot of aerosol but only future studies can show the precise impact.

    Step 3 (impact of CCN changes on cloud properties): I presume that you are talking about whether the change in amount of CCN will be great enough to alter cloud properties? If yes, then that is also something that requires further investigation.

    Step 4 (effect of clouds): I thought that this was relatively well understood? The results from the ERBE experiment (Hartmann, Academic Press, 1993) show that low clouds (below 3 km) have an overall cooling effect.

    Step 5 (GCR trend): I am no expert, but as I understand it is not so easy to determine if there is a trend on the short timescales or not. Carslaw et al (Science 2002) conclude that there is one for this century, but it others arrive at different conclusions.

    Finally an opinion of my own: Press release or not, I am in no way out to attribute what has gone on in the last century solely to cosmic rays or anything else and I am certainly not out to belittle the effect of CO2 and other greenhouse gases. To me this is simply an interesting piece of science that looks like it could be another piece of the climate puzzle. If the size of this piece is big enough to make an impact on past, present or future climate is the subject of future research.

    If anyone has any questions regarding the paper please feel free to ask, and I shall try to answer. I apologize on beforehand for slow responses as I am quite busy doing more experiments at the moment.

    Best regards – Martin

    [Response: Thanks for the comments. As I said above, I think this experiment is of some interest, but the I think you should be concerned at the spin put on it by your co-authors. With respect to the impacts of low clouds - you are correct about their net impact on climate, however, that is something very different to what impact increased aerosols have on low clouds. There is a large literature on indirect aerosols effects, and in particular, those associated with ship tracks. Due to the relatively dirty fuels used by shipping, there is an enormous increase in sulphates following these ships and this can often result in visible cloud trails - however, the circumstances under which this occurs, and the net effect when there are existing clouds are very difficult to ascertain. It certinaly isn't as simple as saying more aerosols - more low clouds - cooling. See recent papers by Andy Ackerman for instance: ... - gavin]

    Comment by Martin B Enghoff — 16 Oct 2006 @ 1:16 PM

  8. re. “I should first apologise for the third solar related posting in as many weeks.”

    Don’t apologize! I personally needed this information and had questions about it until you cleared it up in this article. Great job! Keep doing it!


    Comment by Richard Ordway — 16 Oct 2006 @ 1:26 PM

  9. Martin, you’ve probably read the earlier thread about press releases; tell us about yours? — did you or your coauthors participate in writing, or have an opportunity to edit, that press release before it was sent out? Who did write/edit/approve/release it?

    Comment by Hank Roberts — 16 Oct 2006 @ 1:40 PM

  10. Unsurprisingly, this paper was trumpeted throughout contrarian circles last week and was received uncritically (with one honorable exception in the ‘climatesceptics’ discussion group), even by people who normally spend their time decrying science-by-press-release.

    If this occured via blogs or some other online resource, you (or anyone else reading this thread) really should provide links to this stuff. Milloy is certainly no shock, but it would be interesting to see who else is trumpeting this study. Documenting other people’s willingness to believe is extremely important IMO. This is especially true when it comes to “experts” that have no excuse for falling for such a horribly flawed study.

    Gavin, this was a well written, exceptionally clear and concise post. Keep up the great work.

    Comment by wacki — 16 Oct 2006 @ 2:10 PM

  11. According to thebookseller, Henrik Svensmark and Nigel Calder (ex-editor of New Scientist and author of Cosmic rays before seven, clouds by eleven) have written a book, “The Chilling Stars – a new theory of climate change”, to be published by Icon books.

    “Possibly the most important science book since James Lovelock’s Gaia”

    Anyone else heard about this book?

    Comment by Alf Jones — 16 Oct 2006 @ 2:14 PM

  12. Hi Martin, I’ll correct that on my blog, but you still are high on O3 and UV, which means high on OH. Also, are you sure that the 25 ppb is for SO2 and not DMS?

    Comment by Eli Rabett — 16 Oct 2006 @ 3:02 PM

  13. Sorry I appear to have gotten that backwards. Although the ozone is 25 ppb, if you have a lot of UV, you will have a lot more OH, which is important to the SO2 photochemistry. The SO2 looks high anyhow, even if is not DMS

    Comment by Eli Rabett — 16 Oct 2006 @ 3:12 PM

  14. To play devil’s advocate, the lack of correlation in the figure above doesn’t rule out an effect because there’s an integration between CR forcing and temperature. Svensmark et al. might argue that temperature could be rising in recent decades due to disequilibrium from past CR-cloud changes (i.e. cosmic rays fell, then circa 1950 leveled off at a weak/warming level and it’s taking temperature a while to catch up). The unattributed C14 reconstruction in their background article would seem to suggest that they’re thinking long term. Other recent reconstructions (Muscheler, Usoskin, Solanki) wouldn’t directly refute that argument. What would?

    [Response: The 'catch-up' argument from pre-1950 changes fails because temperature increases are accelerating, not adjusting to a new equilibirum. It would also imply a larger climate sensitivity than we currently think (since the response time and sensitivity are strongly linked). On longer time scales, solar-related effects may play a bigger role, though I have yet to be persuaded that the observations imply a stronger effect than you can get just with irradiance/ozone changes. - gavin]

    Comment by Tom Fiddaman — 16 Oct 2006 @ 3:12 PM

  15. What about the so called Solar Pulse that allegedly exists (hope I am not spouting MTV science again) but I read about it in Fred Pearce’s Book ‘the last generation’ and had appeared to have empirical evidence to back it up.

    Comment by pete best — 16 Oct 2006 @ 3:34 PM

  16. Actually, how about another RC book review? I’d like to see the RC assessment of Pearce’s book…

    Comment by Gareth — 16 Oct 2006 @ 4:52 PM

  17. Re: Step #2 and the effect of aerosols on low cloud. I realise from the response to #7 that this is an active area of research, but I had heard it as an explanation for why aerosols from China were having less of a radiative cooling impact.

    Westerlies would carry Chinese aerosols out over the large Pacific ocean, where they would be rained out before they could reach land, whereas European aerosols would be carried west over the large Eurasian continental landmass.

    Comment by Timothy — 16 Oct 2006 @ 5:37 PM

  18. The warming trends in looking at numerous 100 year temperature plots from northern and high elevation climate stations … i.e. warming trends in annual mean and minimum temperature averages, winter monthly means and minimums and especially winter minimum temperatures and dewpoints … indicate climate warming that is being driven by the accumulation of greenhouse gases in the atmosphere – no visible effects from other things like changes in solar radiation or the levels of cosmic rays. Greenhouse gas emissions are completely overwhelming all other changes in forcing in driving global warming. There are other articles recently put out with spin to downplay greenhouse warming, which I refuse to post at public websites.

    Comment by Pat Neuman — 16 Oct 2006 @ 5:53 PM

  19. Re: Gavin. Thanks for the paper – I´ll look at it.

    Re: Hank. Since I´ve been down at CERN preparing our next experiments I´ve had nothing to do with the whole press release thing and frankly I am not sure exactly how it was made. We all agreed in the group that we did not want it to be another GCR vs. GHW debate but it seems to be this angle that the media is most interested in (sadly, but somehow understandable). I hope that at least in the scientific community it will be the science and not the spin that will be the main focus.

    Re: Eli. Looking at the growth of the particles we estimate the amount of condensable vapour (which in this case is mainly sulphuric acid, from the oxidation of SO2 by OH). In all experiments we seem to be below the level at which classical nucleation theory predict nucleation, but we are getting particles anyway. This has also been observed by Berndt et al (Science 2005). For our new experiments we will (hopefully) get even better estimates of sulphuric acid by using a special mass spectrometer that can detect sulphuric acid at very low concentrations.

    Comment by Martin B Enghoff — 16 Oct 2006 @ 6:13 PM

  20. Gavin : “First, the particles observed in these experiments are orders of magnitude too small to be Cloud Condensation Nuclei (CCN) /…/ aggrandisation of these small particles is in no sense guaranteed”

    On this point (for Gavin, Martin, or anyone else), how do we presently predict the behavior from ultrafine particles (1-2 nm, or even > 3 nm in Svensmark et al experiment) to CCN (approx. 50-100 nm) ? If “aggrandisation is not guaranteed”, could we just expect from cloud microphysics models that more particles > 3nm will most probably imply more CCN in troposphere ? And if no, what are the main theoretical issues about that process (and references to go further) ?

    Comment by muller.charles — 16 Oct 2006 @ 8:58 PM

  21. Another way the sun may interact with climate — I’d sure like some estimate of the relative magnitudes of the various effects.
    – the html version of the file *which was not found

    Solar variability, dimethyl sulphide, clouds, and climate
    S. H. Larsen
    C-Research, Lincoln, New Zealand
    Received 7 July 2004; revised 22 December 2004; accepted 3 January 2005; published 19 February 2005.
    It is proposed that Earth’s climate may be modulated, in part, by changes in the flux of ultraviolet/blue light into the oceans. This occurs, at a range of timescales, through solar variability and from damage to the ozone layer. A conceptual model is presented where, through a number of synergistic processes and positive feedbacks, changes in the ultraviolet/blue flux alter the dimethyl sulphide flux to the atmosphere, and in turn the number of cloud condensation nuclei, cloud albedo, and thus sea surface temperature.
    The greatest effects are expected in the oligotrophic subtropical oceans, under the Hadley circulation, in summer…..

    I know we’re seeing a lot of info recently on how much plankton activity there is; I’d expect a fast feedback from plankton to any cloud change. I don’t know how variation in sunlight relates to variation in cosmic rays at all.

    Comment by Hank Roberts — 16 Oct 2006 @ 9:39 PM

  22. Somehow the average public doesn’t seem to understand that most papers do not go towards establishing empirical data or evidence of the cause and effect relationship in a hypothesis. And the words, link or correlation, do not go towards showing, or providing true evidence of the cause and effect relationship. [Which, Gavin, broke down and outlined in his missing steps paragraph]

    It’s anecdotal and incidental, to use words like “link” or “correlation” or “implies” rather than showing the evidence of cause and effect. (no disrespect intend to the authors of this paper, or anyone else)

    One still has to provide their empirical evidence, data, and provide the methodology that will explain the “why and what”, or say if A occurred before B, then B is the result of A… one still needs to SHOW EVIDENCE that A caused B not “imply” because A happened first, its linked, or correlated, because this may or may not be true.

    A supporting hypothesis gives credence to an underlying explanation for a cause and effect relationship for which one is claiming that would go towards explaining the nature of the how, the why, the what, … of the cause and effect behind a scientific hypothesis.

    I do understand there is room for a certain amount of creativity in the scientific world in research undertaking to be interestingly liberal, but if one wants their hypothesis to show cause and effect relationships, then it’s part of the standard scientific method to publish it with the research establishment evidence of the cause and effect relationship in one’s papers rather than correlations, links, or anecdotal notions to buttress it.

    Furthermore, many high profile journals, that I will not mention (check the article submission rules) , seem to seek to publish papers that are of interesting readership content, even if they are peer reviewed, rather than being concerned if a paper is providing documentation of a cause and effect relationship to their reading audience.

    Comment by barbie doll moment — 17 Oct 2006 @ 12:23 AM

  23. This seems relevant:

    “Empirical evidence for a nonlinear effect of galactic cosmic rays on clouds

    Galactic cosmic ray (GCR) changes have been suggested to affect weather and climate, and new evidence is presented here directly linking GCRs with clouds. Clouds increase the diffuse solar radiation, measured continuously at UK surface meteorological sites since 1947. The ratio of diffuse to total solar radiation ‘the diffuse fraction (DF)’ is used to infer cloud, and is compared with the daily mean neutron count rate measured at Climax, Colorado from 1951-2000, which provides a globally representative indicator of cosmic rays. Across the UK, on days of high cosmic ray flux (above 3600-102neutron counts 1, which occur 87% of the time on average) compared with low cosmic ray flux, (i) the chance of an overcast day increases by (19±4) %, and (ii) the diffuse fraction increases by (2±0.3) %. During sudden transient reductions in cosmic rays (e.g. Forbush events), simultaneous decreases occur in the diffuse fraction. The diffuse radiation changes are, therefore, unambiguously due to cosmic rays. Although the statistically significant nonlinear cosmic ray effect is small, it will have a considerably larger aggregate effect on longer timescale (e.g. centennial) climate variations when day-to-day variability averages out.”

    Comment by John Lederer — 17 Oct 2006 @ 7:59 AM

  24. I find the discussion here, especially the posted plot, quite misleading. Svensmark, et. al., claim that cosmic rays have a strong effect on low cloud cover, not a direct effect on the temperature. There is extremely good evidence that is true as can be seen from Figure 4c in . I also find it appealing that they test their proposed mechanism with an experiment, not a computer model, which can be refined until the details of the cloud modulation are understood.

    [Response: Possibly you are not reading the same text as me: "During the 20th Century the influx of cosmic rays decreased and the resulting reduction of cloudiness allowed the world to warm up." (second paragraph). The cloud correlation plotted only goes up to 1995 and using the same data, completely breaks down subsequently. The correlation is 'rescued' by making an arbitrary 'correction' that is not supported by the original data generating group (ISCCP) but that just 'happens' to match their previous correlation. If you find this appealing.... well, what can I say? - gavin]

    Comment by Paul Linsay — 17 Oct 2006 @ 10:53 AM

  25. Re #23: This is a much more useful result than Svensmark et al, and the take-home conclusion from it is that while the GCR effect on clouds is real it can’t explain late 20th century warming.

    There’s also a pretty recent overview of the whole issue here.

    Comment by Steve Bloom — 17 Oct 2006 @ 1:31 PM

  26. Gavin, I disagree. Cosmic rays modulate the cloud cover which in turn affects the temperature by trapping or releasing radiation to outer space. This is unlike CO2 which traps radiation directly. Second, the low cloud/CR correlation holds through at least 2002. See Figure 3 of E. Palle, et. al., Journal of Atmospheric and Solar-Terrestrial Physics 66 (2004) 1779-1790

    Comment by Paul Linsay — 17 Oct 2006 @ 1:34 PM

  27. Re: 24/Gavin: The correlation is ‘rescued’ by making an arbitrary ‘correction’ that is not supported by the original data generating group (ISCCP) but that just ‘happens’ to match their previous correlation.

    The alternative, which is not entirely implausible, is that clouds correlate to cosmic rays but there is also some other effect whose influence is comparable in magnitude to the correlation and is responsible for the trend. One can “rescue” the correlation by removing a smooth quadratic fit over the whole record, just as easy as applying Svensmark et al. abrupt slope adjustment. If you permit one to remove the trend then the correlation continues to be reasonable, but if one accepts that there is some other large variation unrelated to cosmic rays, then of course that diminishes the relative significance/importance of the cosmic ray correlation.

    Comment by Robert A. Rohde — 17 Oct 2006 @ 2:27 PM

  28. Re:25, the link to the overview does not work, Re: 26 is there a link somewhere to this figure that is not via subscription?

    Also I see that the Danish Space Research Institute involved with the study is primarily supported by two private foundations. Not to be skeptical but what are these foundations?

    Comment by Brian Allen — 17 Oct 2006 @ 5:10 PM

  29. Re: 24/Gavin: The correlation is ‘rescued’ by making an arbitrary ‘correction’ that is not supported by the original data generating group (ISCCP) but that just ‘happens’ to match their previous correlation.

    I don´t think you are fair here, as in some of your other points. The calibration was done since there was a gap between two ISCCP satellites – thus no overlapping intercalibration. They then did a comparison and calibration using an independent satellite data set. One may disagree but their arguments are fairly strong. Just look at the big jump in the high cloud time series here

    Comment by Paal — 17 Oct 2006 @ 6:04 PM

  30. I have a couple of questions that I have never seen addressed by the high-climate sensitivity scientists. First, how do you reconcile a high climate sensitivity (say 3-5 C/doubling) with the fact that there is very low correlation between CO2 and climate in the 500 million time scale? Especially concerning is how it is possible to reconcile concentrations more than 10 times higher than current CO2-levels with am ice age epoch even colder than the current epoch.

    Second, as far as I can tell the only scientific motivation for a high climate sensitivity is to be able to reproduce the ice ages with milankovitch cycles. However, the assumption here is that the only cyclic signal is due to changes in the Earths orbit, but evidence (e.g. Sharma02) suggests that the sun itself may be varying in activity. I have to this date never seen these variations in actual solar activity/cosmic ray flux taken into account when modelling previous ice age cycles, which I find deeply concerning. Empirical evidence suggests that there is a much larger external climate forcing than the Milankovitch cycles and this in turn implies that climate sensitivity must be much lower than currently believed.

    Thirdly, any answer to why the tropical troposphere seems to becoming dryer recently? This seems like completely at odds with model predictions.

    Thanks in advance.

    Comment by Onar Am — 17 Oct 2006 @ 7:33 PM

  31. heh, speaking of overselling papers somebody sent this to me today.

    It’s an article on climate change titled:

    A load of hot air?

    Dr Hans Von Storch, a leading German climate scientist and fervent believer in global warming, is convinced the effect of climate change is being exaggerated.

    “I agree the 11C figure was unreasonably hyped. It’s a difficult line for all scientists to tread, as we need something ‘exciting’ to have any chance of publishing… to justify our funding,” one scientist wrote us.


    [Response: We discussed this exact issue at the time: - gavin]

    Comment by wacki — 17 Oct 2006 @ 9:15 PM

  32. Re 28 what are these foundations?

    Probably nothing too sinister. If you search
    it’s all pretty boring – like NASA and the ESA. It looks to me like a real government agency that gets some incidental foundation funding.


    Comment by Tom Fiddaman — 17 Oct 2006 @ 10:33 PM

  33. Solar posts are way more interesting than posts on editorials or congressional hearings.

    Comment by C. W. Magee — 17 Oct 2006 @ 10:53 PM

  34. Re 26

    It’s nice to see that Palle et al. have toned down the language a bit, from
    The above analysis, working from the observed correlation
    of low cloud factor with cosmic rays and solar activity
    indices, has serious implications for our understanding
    of the causes of climate change in the past century
    as it suggests that most of the global warming during
    this period can be attributed to the combined direct (irradiance)
    and indirect (low cloud factor) effects of solar
    (extrapolating from ’84-’93 data)


    In previous sections, it has been shown how the
    evidence for a connection between GCR and low clouds
    is inconclusive; though some aspects of our study are
    encouraging, others are basically negative. Despite these
    uncertainties, because of the potential impact on the
    Earth’s radiation budget, we have explored the consequences
    for climate change, should the correlation
    between low cloud and ionization be confirmed.

    There is relatively good agreement between the observed
    anomaly and the combined curves for the period
    1870-1910, but increasing divergence from 1910 onward.
    By the 1990s, the difference is of the order one
    third to one half of the global warming since the late
    19th century.
    Thus it appears that, provided further satellite cloud
    data confirms the cosmic ray flux low cloud seeding
    hypothesis, and no other factors were involved over the
    past 150 years (e.g., variability of other cloud layers)
    then there is a potential for solar activity induced
    changes in cloudiness and irradiance to account for a
    significant part of the global warming experienced
    during the 20th century, with the possible exception of
    the last two decades.
    However, lest the previous sentence is taken out of
    context, we should point out that there is clear evidence
    that total cloud cover has changed over the past 150
    years (Palle and Butler, 2001, 2002). If this were
    confirmed then the predictions above are incomplete as
    changes in cloud at other levels will also alter the energy
    balance with a contribution that could be either positive
    or negative.
    (Palle et al. 2004)

    It seems like it would be easy to test this sort of hypothesis in a simple EBM attribution study like Crowley 2000 rather than as an isolated phenomenon as above and in Scafetta & West. Hope someone does.

    Comment by Tom Fiddaman — 17 Oct 2006 @ 11:00 PM

  35. Re #28: It works fine for me (with IE). It is a 6.35 MB PDF file, so perhaps that’s your problem?

    Comment by Steve Bloom — 18 Oct 2006 @ 3:23 AM

  36. I noticed something odd… In Figure 4 of the press material in Danish there is a good correlation between the cosmic rays and the low clouds up to 2005, but in Figure 4 of the English version, the curves only go to 1995. I had the impression that the correlations broke down after 1989 (Damon & Laut, 2004), and Svensmark had to ‘correct‘ the cloud data in order to improve the fit. He argues that there is a problem with the ISCCP data (Figure 1 in the manuscript with the title ‘GCR and ENSO trends in ISCCP-D2 low cloud properties‘). It is not mentioned in the Danish press material that the curve representing the clouds have been ‘corrected’. I think that this should have been mentioned, even if such a correction were widely accepted. But I do not see that such problems are mentioned on the webpage with the title ISCCP KNOWN AND FIXED ERRORS IN DATA PRODUCTS. So, is there really a problem with the ISCCP data, or not? What have I overlooked?

    Comment by rasmus — 18 Oct 2006 @ 3:39 AM

  37. re#36
    Problems with satellite data, especially when there is just one source of data, are not so rare. Remember UAH’s rate of troposphere warming in the 80′s and 90′s. As Paal said (#29), Marsh and Svensmark justified their correction on this point. Anyway, as I have previously suggested, I think it would be more relevant to look at regional correlations, which should better fit because of different factors (geomagnetic field variations, presence or absence of aerosols that already act as CCN, etc.)

    Comment by muller.charles — 18 Oct 2006 @ 5:19 AM

  38. Re 30: You are mistaken, ice ages cycles predict sensitivity towards the low end of IPCC values, though they may be the victim of bad data. High climate sensitivity comes mostly from some climate models, as far as I know.

    Comment by Robert A. Rohde — 18 Oct 2006 @ 5:26 AM

  39. Re #30:

    The Sun’s luminosity has increased substantially over the last 500 million years and will continue to slowly increase over the next serveral billion years until it becomes a red giant. One would thus expect a higher temperature today for the same CO2 levels than 500 mya.

    Comment by yartrebo — 18 Oct 2006 @ 8:31 AM

  40. There is a missing #6 in your list above, after you’ve done #s 1 through 5. You also have to show that the magnitudes match up; that is, that the long-term decrease in GCRs explains the amount of warming that we see in the late 20th and early 21st century. Just as an order-of-magnitude effect, it appears from Fig. 4 of that low cloud cover changes maybe 1.5% in response to a full cosmic-ray cycle of 14%. If we allow that all those clouds are cumulus with an albedo of 0.8 and that they block water with an albedo of 0.1, that translates to a change in global albedo of 0.014. A global change of albedo of 0.014 in my simple Arrhenius model of the Earth equates to a temperature of 1.4 K, or maybe 2.4 K after feedbacks; I’m not sure, since the GISS site with Hansen’s models is inexplicably offline as I write this. From your graph above, it would seem that there is no long-term trend in GCR; certainly if there is a trend, it is small. A linear regression fit to your smoothed data in the graph sampled every 3 years or so gives a downward trend with a value of about 7% of the size of a solar cycle over the 40-year span observed. 7% of 2.4 K is a full-range shift of 0.17 K, versus an observed warming of roughly 0.4 K over the same period. So we’re shy by a factor of 2.4, if we want to explain the bulk of global climate change by GCRs. This estimate is generous to the GCR hypothesis, since the cumulus-to-water albedo shift exaggerates the true change of low clouds, and I need bond albedos in my calculation and I’m using visible albedos. Apparently we shouldn’t neglect GCRs, but they don’t explain most of the warming, either.

    Comment by Steffen Christensen — 18 Oct 2006 @ 10:40 AM

  41. I am speaking out of ignorance–fair warning!

    The relatively weak correlation between measured cosmic rays and measured cloud cover does not seem to me to be a very
    strong point against the theory being valid or it being a strong factor in climate. The process, under real world conditions, seems poorly understood. As a consequence until one can determine precisely what to measure, any correlation is likely to be weak.

    Compounding factors that occur to me are:

    1. Cosmic rays vary in energy levels. Are certain energy levels much more involved in cloud formation, and if so which ones, and do we have a good historical record of those?

    2. Despite several statements along the lines of the Climax data being well correlated with world wide data, there seems to be variation among global stations and measurements. e.g.
    or compare data sets at

    This would suggest that location matters, and if location matters, that immediately raises the question of where we should look for resulting clouds– an hour “downwind” meteorologically of the cosmic ray measurement, two hours, eight hours?

    If location matters it also suggests that there will be different relationships between data measured at a particular station and cloud formation — weather formation is influenced by terrain, winds aloft, humidity, and a host of other factors.

    3. The theory suggests an interaction between cosmic rays and atmosphere. Atmosphere is not uniform over the earth in location or time. Is the interaction modulated by water vapor, by the density aloft of the atmosphere (which is not exactly the same thing as surface pressure), etc. ?

    In short we may be in the position of trying to determine if a kitchen stove boils water by measuring the humidity in the living room versus household natural gas consumption. There is likely to be a correlation but it is likely to be weak. Until we know well what to measure, we shan’t see a good correlation.

    Nonetheless, it seems to me the theory may be on to something. The albedo of the earth is a first order factor in the energy balance, and a small change in the albedo has much practical import. Proof or disproof, I suspect, will require fine measurement of the right things. I hope we get to that point.

    Comment by John Lederer — 18 Oct 2006 @ 11:01 AM

  42. Re #39

    That could explain a long term trend but does not explain the low correlation between CO2 and temperature in the 500 million year time frame. The fact that temperatures have been very high when CO2 was low and vice versa suggest a weak causal relationship, i.e. a low climate sensitivity.

    Comment by Onar Am — 19 Oct 2006 @ 3:17 AM

  43. Re #38

    I find this very interesting. According to Shaviv 2005 (see: most of the empirical data implies a climate sensitivity at the low end of the IPCC range, even without cosmic rays.

    Comment by Onar Am — 19 Oct 2006 @ 3:25 AM

  44. Re #39 and “The Sun’s luminosity has increased substantially over the last 500 million years and will continue to slowly increase over the next serveral billion years until it becomes a red giant. One would thus expect a higher temperature today for the same CO2 levels than 500 mya.”

    The Sun’s luminosity has only increased by about 40% over the last 4.5 billion years. The increase over 500 MY would be only a few percent, and from the Stefan-Boltzmann law (temperature follows the one-fourth power of flux), the effect would be too small to notice. Also, you’re assuming the Earth’s atmospheric composition and surface arrangement and albedo were the same over that period. They probably weren’t.


    Comment by Barton Paul Levenson — 19 Oct 2006 @ 7:05 AM

  45. Re #42:

    500 million years is plenty long enough for this effect. The effect is in the ballpark of 5%, since the sun is 30% brighter than when it formed 4.5 billion years ago and the brightening trend accelerates as a star ages (A little educated guessing here, but the rate of fusion increases in proportion to the star’s luminosity and the pressure needed in the core is an inverse relationship to the hydrogen concentration in the core – simple linear interpolation would give a 3.3% increase in luminosity).

    PS: When were temperatures high and CO2 levels low? From what I understand of the historical record, temperatures moved in line with CO2 with a slow warming superimposed on this (or a slow drop in CO2 levels superimposed).

    Comment by yartrebo — 19 Oct 2006 @ 8:57 AM

  46. Hi Gavin

    there is an apparent correlation between the detrended low cloud cover (from ISCCP) and the GCR.
    Between a maximum and a minimum of solar activity (or between a minimum and a maximum of GCR flux) there is a variation of 1% of the mean low cloud cover.
    Be careful it’s not a relative variation but the absolute variation.

    the mean low cloud cover is about 28% (from ISCCP).

    The low clouds are responsible of 25% of the global albedo and in consequence of about -25 w/m2.

    The absolute variation of 1% leads to -0.9W/m2.
    In the same time the TSI RF is about -0.25 W/m2 (-1/4)

    So the total influence of the 11 y cycle variation is greater than -1W/m2.

    with a climate sensitivity of 0.75°C.m2/W this gives 0.7 to 0.8°C variation (without accounting of thermal inertia)

    It’s maybe the same problem for the long term solar activity variation from 1910 to 1950.

    So what is false in this?

    [Response: Low clouds seen by ISCCP are only about a half to two thirds of all actual low clouds (because ISCCP looks down and cannot see a low cloud if there is a high cloud above it). Calculations of 'Cloud radiative forcing' (which is a specific kind of diagnostic - Cess et al definition) are not the same as the 'radiative forcing' in the sense of CO2. It is actually quite difficult to work that out and depends enormously on what kind of environment the extra clouds/aerosols are in (this is one of the big 'missing steps'). You cannot use equilibrium climate sensitivity to estimate the response to an 11 year periodic forcing - precisely because it is not in equilibirum! (and there is absolutely no evidence of anything more than about 0.1 deg C possibly solar-cycle-related expression in surface temperature records - and even that can only be seen after very careful removal of ENSO and volcanic effects). And finally, the problem in the long term (pre-1950) is that we don't have any cosmic ray records from then and the proxies (14C, 10Be from Greenland and 10Be from Antarctica) all give different trends. Thus, there is no good calibration to forcing from CR intensity and even if there was, we don't have a good record of CR intensity going back in time. And for the period we do have a record? There is no trend at all. -gavin]

    Comment by Pascal — 19 Oct 2006 @ 9:28 AM

  47. On the Marsh and Svensmark (2003) trend ‘correction’ to the ISCCP low cloud data

    I went to discuss this with the ISCCP scientists (downstairs) to get their opinion and this is a rough summary of the issues:

    1) ISCCP inter-satellite calibration is done by offsets for individual satellites, not through trends. For instance, calibration is done using the warmest and coldest deciles from the satellite radiances. Whenever a new satellite stream is introduced there will be offsets in various parameters (so far ISCCP merges data from 33 different satellites) since the calibrations are done for a limited selection of targets, the satellites sometimes see different things and there maybe subtle diurnal or angle related differences. Any new satellite can cause a jump, but it cannot produce a continuing trend. Calibrations are done directly against NOAA-9 (which was the best calibrated of all the satellites and serves as a gold standard for subsequent instruments). Thus the calibration of NOAA-14 (and NOAA 16 – from 2001) is performed directly against the NOAA-9 values, not with respect to overlapping satellites: ). Thus there is no way the 1994 gap between NOAA-14 and NOAA-11 could have produced an ongoing trend in the ISCCP data.

    2) The MS03 trend correction is based on the apparent difference between SSMI and ISCCP. But SSMI only sees water clouds and ISCCP sees both ice and water clouds, thus the trend could be a real effect, or it could be related to drifts in either or both instruments or to drifts in the calibration targets. It certainly can’t be assumed only to be a problem with ISCCP, and cannot have anything to do with the ‘gap’ mentioned above (since that would simply have produced an instantaneous offset).

    3) The overall accuracy at the global mean level is at least 2% (one sigma) in the cloud amounts and thus none of the trends or apparent cyclic behaviour at the global mean level are significant.

    Bottom line: there is absolutely no good reason to put in a trend correction becasue of a gap in the satellites.

    Comment by Gavin — 19 Oct 2006 @ 3:02 PM

  48. I am a keen observer from NOAA satellite eyes as well, this time with Polar Orbitting ones. If cosmic rays cause more clouds, then one must look at places where they are hard to form. This would be during the Polar winter over the Arctic Ocean, say mid February, where clouds are scarce. Looking for clouds where there shouldn’t be any is perhaps the only way to demonstrate Cosmic Ray effects. Over the long night, when the Arctic Ocean is mostly totally frozen, the only (non cyclonic) clouds that be are caused by leads (from open water), caused by tidal and wind effects, there are no other aside from ocean air flows. Where are those Cosmic Ray low clouds? Shouldn’t there be some, in a middle of nowhere , with barely enough moisture to create them? By the way, low clouds in darkness increase surface temperature, sort of like the inverse property of commonly understood Cosmic ray effect, not causing a cooling because there are more CR’s, but rather a warming, which only low clouds in total darkness can do, so the probable CR temperature signal gets cancelled from one latitude dark vs bright region to the next. What happens to GT’s then? Should there be no GT temperature trend at all? CR proposed effects are fascinating, would be more interesting if CR proponents can show a few observable examples which actually cause a net trend in temperature. Planet wide .

    Comment by wayne davidson — 20 Oct 2006 @ 1:12 AM

  49. Re 42

    On the 500 Mio year time scale you have to consider continental shifts which have important impacts on climate (e.g. completely different global ocean circulation).
    There are many factors influencing climate at the same time on all time scales. Thus you will never find a good correlation of one factor at all times. You always have to account for the influence of the other factors before you look at the correlation.

    Comment by Urs Neu — 20 Oct 2006 @ 5:37 AM

  50. Re 43

    The Shaviv 2005 paper has many problems (to be cautious…). Some of the problems are the same which Gavin mentioned in his reply to 46 above (Mixing of Cloud Radiative Forcing and TOA radiative forcing, uncertain CRF before 1950) but there are many more (e.g. a lot of necessary assumptions to get to the result, etc.).

    Maybe Gavin could comment more in detail. If he hasn’t seen the paper yet, he will be absolutely delighted to see such a nice pleading for cosmic rays influence. The end of the discussion section is really impressive.

    Comment by Urs Neu — 20 Oct 2006 @ 6:20 AM

  51. #48
    “Looking for clouds where there shouldn’t be any is perhaps the only way to demonstrate Cosmic Ray effects.”
    On long term trends, you may be right. But on short term influence, you can also observe the correlation with Forbush decreases (Todd 2001, Harrison 2006).

    Comment by muller.charles — 20 Oct 2006 @ 8:10 AM

  52. Hi Gavin,

    you write that:

    “the problem in the long term (pre-1950) is that we don’t have any cosmic ray records from then and the proxies (14C, 10Be from Greenland and 10Be from Antarctica) all give different trends”

    10Be from Greenland and Antartica agree quite well for the period before 1950 AD. The main disagreement comes from the period after 1950 AD. 10Be from the South Pole increases and 10Be from Southern Greenland decreases. So both records exhibit disagreement with the neutron monitor data. These differences have led to the different conclusions about the solar activity in the past (see ).

    However, the long-term (pre-1950) changes in 10Be from Greenland and Antarctica agree quite well. The changes are also supported by the 14C data.

    [Response:Thanks! - gavin]

    Comment by Raimund Muscheler — 20 Oct 2006 @ 9:46 AM

  53. It might be worth noting that this experiment is to be expanded upon at the CERN particle accelerator using, its claimed, â??clean airâ?? etc.
    It has gathered quite a collection of institutions as multi-disciplinary partners.

    CLOUD proposal


    Comment by Jay Furneaux — 20 Oct 2006 @ 11:58 AM

  54. Re #39, #42, 49, etc. Two questions.

    First, there are a number of factors (some obvious even to a casual observer like me) that could have affected climate on a 500 My timescale. Continental movement has already been mentioned. IIRC there’s also evidence for significant changes in atmospheric composition & pressure, possible long-term orbital variations, etc. But what no one seems to be asking is whether the temporal resolution of measurements over this period is fine enough to track the effects of CO2 on the decade to century timescale that is of practical interest re GW?

    Second question: In the 100 Ky timescale for which there is high resolution data, AFAIK there’s no instance of (and no mechanism for!) significant CO2 being added to a stable climate, previous to the modern anthropogenic CO2. So for instance you might have a climate warming that releases dissolved CO2 from the oceans, and that CO2 might further drive the climate. But isn’t claiming that CO2 lags change in this period a fallacious argument, since there’s no instance of an increase absent a such a change?

    FTM, doesn’t the historical record in fact suggest that we ought to expect additional natural CO2 to be released as the Earth warms in response to the anthropogenic CO2?

    Comment by James — 20 Oct 2006 @ 1:49 PM

  55. Re:2 Sulfate VS Ions from outer space

    “UPDATE: It occured to the old hare that he needs to use a hammer.

    * Everyone accepts that cosmic rays are the principal source of ions in the lower atmosphere. The ion density is around 1000/cm3.
    * Everyone accepts that there will be nucleation around the ions because of electrostatic forces

    The Svensmark et al. paper simply restated the obvious. But the real questions are:

    * Is the availability of ions the limiting factor in forming cloud condensation nuclei or is the availability of other species limiting.
    * Are there other ways of forming cloud condensation nuclei (CCN) besides around ions and if so (it is so) what is the relative importance of each type of CCN and what are the characteristics of the CCNs.

    And, I think the figure at the end from a Mexico study pretty well shows that under normal conditions SO2 is limiting for forming small aerosols.”

    But one of the most convinient if true is the following Qestion.

    * Do negative charged air increase the optical thickness of SO2 induced clouds/smog/fog/local dimming under an hot mexican sun ?

    Comment by Peer — 20 Oct 2006 @ 4:10 PM

  56. Havn’t I read that there are differences in the warming pattern which should be expected (and has been predicted) from solar contra greenhouse gas forcing? For example GHG forcing is expected to cause night time, winter, high latitude warming..? Have these factors been overlooked with all this talk of….calibration of NOAA-14 (and NOAA 16 – from 2001) is performed directly against the NOAA-9 values, not with respect to overlapping satellites..!!etc..
    A short summary of the two warming patterns expected would be very much appreciated by us laymen….anyone?

    Comment by Rick — 20 Oct 2006 @ 5:19 PM

  57. Re #54

    I agree with you, especially on point #2. From my amateurish viewpoint it’s rather obvious that in pre-anthropogenic times, changes in CO2 levels were driven by temperature changes (as a rule) and that these presumably fed-forward to “reset” the ambient temperature to a new equilibrium (resulting from the forcing – solar most likely – that increased both the temperature and the CO2, or decreased these as the case may be). The CO2 released under these conditions contributed rather minimally to temperature levels and certainly so in relation to the very large increases in CO2 from anthropogenic originsthat we’re seeing now. That seems to apply at least through the glacial/interglacial cycles.

    Of course significant changes in CO2 might arise within a stable climate due to catastrophic effects. Thus the end-Cretaceous period with hugely increased atmospheric CO2 levels were (I think) a result of either/and/or the dinosaur-killing impact that occurred in a limestone rich sediment that released massive amounts of CO2…and the ginormous volcanic eruptions that produced the Deccan Traps in India and released enough lava to cover the entire USA to a depth of more than 1 kilometre (if it had actually been released in what was to be the USA rather than in what was to be India!).

    Your last point is also correct. In fact on the second thread on this blog Dr. Scafetta is pursuing a related point..that solar influences are responsible for some of the enhanced 20th century CO2. But I would have thought the evidence from the glacial history would indicate that warming-induced CO2 levels from non-fossil fuel reservoirs are small. We have raised CO2 levels from around 280 ppm to 385 ppm with an increase in temperature of around 0.7 oC plus perhaps 0.2 oC (if we were to remove the cooling from aerosols) plus perhaps 0.5 oC (the warming still “in the pipeline”)..say 1.5 oC all together to come, but more relevantly only 0.7 oC actually extant. But the 180 to 280 ppm glacial to interglacial rise in CO2 is associated with around a 6 oC change in temperature (Is that about the right value of a post glacial temperature rise?). So clearly the bulk of the post glacial warming is from direct solar influences with a relatively minor part from solar-induced recruitment of CO2 from natural reservoirs. And the contribution to 20th century CO2 levels resulting from recruitment from reservoirs due to solar and/or anthropogenic warming feedbacks must be rather small (no more than 10-15 ppm or so if we were to scale with respect to the glacial-interglacial transition. The experts would be able to make these “calculations” more precisely than me!)

    On the other hand, an anthropogenic CO2 -induced release of carbon and methane from tundra and deep sea clathrates etc. might eventually fed-forward in a rather non-linear (catastrophic!) manner at some point!

    Comment by chris — 20 Oct 2006 @ 5:30 PM

  58. Re #49

    “Thus you will never find a good correlation of one factor at all times.”

    That’s actually not true. Cosmic rays/solar activity give excellent correlations at all times and at all time scales. (ranging from days such as the recently cited Forbush events to hundreds of millions of years such as the work by Shaviv cited above) This is evidence that cosmic rays are a formidable factor in climate, so great that it can even overshadow the effects of continents on ocean circulation.

    Comment by Onar Ã?m — 20 Oct 2006 @ 7:43 PM

  59. Re 58

    I have never seen excellent correlations for cosmic rays and solar over all time scales. There are claims of such correlations, but they are far from convincing. Reconstructions are so different and have such high uncertainties especially on the multimillion year time scale, that it is no problem to show either a match or a mismatch of the same parameters by choosing specific data set, tuning the data (within the frame of the uncertainties) and making enough assumptions.

    Comment by Urs Neu — 21 Oct 2006 @ 4:51 AM

  60. re: 56.

    In reply to 56, The warming trends in looking at numerous 100 year temperature plots from northern and high elevation climate stations … i.e. warming trends in annual mean and minimum temperature averages, winter monthly means and minimums and especially winter minimum temperatures and dewpoints …

    Climate warming is being driven by the accumulation of greenhouse gases in the atmosphere – no visible effects from other things like changes in solar radiation or the levels of cosmic rays. Greenhouse gas emissions are completely overwhelming all other changes in forcing in driving global warming.

    There are other articles recently put out with spin to downplay greenhouse warming, most recent included links below. As I said in calling Senator Dayton’s office yesterday, the articles below are not accurate – all just smokescreen attempts to mislead the US public into voting against any political parties that may show support for reducing greenhouse gas emissions. So far the only party that has shown any strong support for reducing US greenhouse gas emissions has been the Green Party, but some people may think that one or the other of the major parties actually supports action to reduce CO2 emissions. Neither major party supports reducing emissions by using fewer products, building smaller homes, having fewer children and, above all, traveling only when needed.

    Three recent Antropogenic (AGW) skeptic articles, below:

    U.S. Commission Environment and Public Works
    Majority Press Release
    Decorated Scientist Defects From Belief in Global Warming â?? Caps Year
    of Vindication for Skeptics
    October 17, 2006
    Washington DC – On
    Decorated Scientist Defects From Belief in Global Warming â?? Caps Year
    of Vindication for Skeptics
    # # # # #

    Open Kyoto to debate – Sixty scientists call on Harper to revisit the
    science of global warming
    Published: Thursday, April 06, 2006
    An open letter to Prime Minister Stephen Harper:
    National Post
    Part of the network
    Sixty scientists call on Harper to revisit the science of global
    # # # # #

    Debra J. Saunders: Many take global warming on faith
    Debra J. Saunders, San Francisco Chronicle
    published: October 19, 2006

    Three recent AGW skeptic articles, above.

    Comment by Pat Neuman — 21 Oct 2006 @ 9:09 AM

  61. Speaking of spin, where did all the hurricanes go?

    Comment by Crocodile Hunter — 22 Oct 2006 @ 9:52 AM

  62. re: 61. A developing El Nino in the Pacific effectively limited Atlantic hurricane development due to increased wind shear. And yet, despite the El Nino, we are now at the average climatological number of storms for the year. Amazing! During an El Nino season, we expect far below normal numbers of storms. And yet we still had an average year. Clearly, as the peer-reviewed studies have indicated, the base-line for storms has been raised due to climate change. With the El Nino developing, this should have turned out as a below normal season. It wasn’t.

    Comment by Dan — 22 Oct 2006 @ 7:47 PM

  63. re 62: Newton’s third law of climatology: for every climate explanation, there’s an equal and opposite explanation.

    Comment by Crocodile Hunter — 22 Oct 2006 @ 10:04 PM

  64. re: 63. Nothing “opposite” there. It is a simple, accurate scientific explanation that fits perfectly with the current studies about hurricanes and climate change.

    Comment by Dan — 23 Oct 2006 @ 6:05 AM

  65. Re #63 Newton’s laws do not concern climatology because they describe linear systems. The climate is a non-linear dynamic (chaotic) system, for which the First Law rule is that that every law has an exception. The exceptions to this law are Newton’s Laws :-)

    [Response: Ummm... Newton's laws are the basis for the Navier Stokes equations which are highly non-linear. And chaotic dynamics in weather are a purely classical phenomenon - no special relatively there! - gavin]

    Comment by Alastair McDonald — 23 Oct 2006 @ 6:46 AM

  66. Re 65:

    Let me echo Gavin. Newton’s equations are linear only if the forces are linear, which is seldom the case. In many circumstances one can use linear approximations within certain narrow ranges, but in many applications that is not feasible. A classical example is celestial mechanics. Most of chaotic dynamical systems is done starting with Newton’s laws, and is entirely classical.

    People should be careful about throwing around words that they don’t understand.

    Comment by Leonard Evens — 23 Oct 2006 @ 10:34 AM

  67. Re 62: But did El Nino form early enough and was it strong enough to have a significant effect on the hurricane season this year? Also, some scientists think the AMO is entering its positive (warm) phase – so, we would have expected an above average year based on that alone without the climate change signal. (Yes, I know, some scientists think the AMO is bogus.) I’m not disputing that climate change is occurring or that it’s a likely factor in hurricane formation. There’s ample evidence of climate change. But is the connection between El Nino, climate change and this year’s Atlantic hurricane season solid or is it more speculative?

    Comment by an old federal regulator — 23 Oct 2006 @ 1:02 PM

  68. In Reference to Original Post:

    Dear Dr. Schmidt;

    Just a request for clarification of the statement “One could quibble with the use of the high-energy UV (which never penetrates to the lower troposphere)”, what high-energy UV are you referring, UV-A, B or C EM energy, or could it be the energy insolation at altitude? I only mention it as this as the lack of presence of these frequencies seems inconsistant with general knowledge wrt terrestrial UV shielding requirements. Even if you are not being frequency specific and are speaking of energy content, is there not a recent change in the levels wrt the recent apparent Stratospheric Ozone reduction?

    Do we have any non-Labratory radiant energy measurement of the energy levels or changes of the energy levels/frequency at or above the 250mb altitude range with which to refute the study? (I reviewed the site and did not see any at altitude, only terrestrial readings and those were not high enough in resolution (through 2004) to be of much use.) I have not seen any measures in the TOA readings on any of the satellites that Dr. Scafetta was using in his Duke University studies either. (Any chance the next gen MODIS or EOS birds will have an experiment included to measure high “Q” (resolution) cloud top spectral (EMR) reflections?)

    I just mention this in passing as the energy levels required for the formation of the nitric tri-hydrates in the polar regions would appear to require a significant input of photonic energy to form in the presence of the PSCs (in the 16 to 24 km range)would it not? Also, if I understand correctly, this chemical phenomena is fairly recent or was this only due to a lack of measuring it until around 2003?

    Dave Cooke

    Comment by L. David Cooke — 23 Oct 2006 @ 1:12 PM

  69. Around 1910 people thought that CO2 increases wouldn’t warm the planet for two reasons – (1) experimental setups showed that the infrared window was already saturated with respect to CO2 and H2O- adding more wouldn’t make a difference, and (2) it was assumed that the ocean would rapidly absorb any excess CO2 produced by fossil fuels.

    Gilbert Plass showed that the initial experiments were flawed – cold air at lower pressure behaved differently than at sea level (every spectroscopist knows that if you want sharper, tighter absorption bands you put the sample in liquid nitrogen, for example). (Charles Keeling’s measurements showed that the CO2 was not all going into the oceans)

    It seems that there are similar flaws in the connections between experiments described in this paper and the global climate system

    If you want a little background on cosmic rays and the magnetic fields of the Earth and the Sun: (Cosmic rays) (Solar magnetic field)
    If you look at the second link, you’ll see a graph of the sun’s solar activity; according to the ‘cosmic ray theory’ you should see ‘cool cloudy summers’ peaking around 2001 and warming peaking around 2006. Well… that doesn’t seem to fit!

    Another site worth looking at is
    However if you follow the link to ‘cosmic rays and the atmosphere’ they have a link titled “Influence of Cosmic Rays on Earth’s Climate” which takes you right to Svensmark’s page:

    It’s probably nothing more nefarious than trying to drum up attention for SLAC-related research. High energy physicists seem to live in a bit of a bubble, but that’s going a bit overboard. Stanford – tut, tut, tut.

    The main gem at the authors web site is this:
    “Estimated effect of the increase of CO2 (1750-present): 1.5 W/m2
    Estimated effect of doubling of CO2: 4 W/m2
    Radiative effect of clouds (cooling): 17-35 W/m2″

    Plus, the ‘references’ link only includes the author’s own work! That’s not how the references section is supposed to work…

    And from the author’s press release:
    “William Herschel, a famous astronomer in England, suggested in 1801 that the price of wheat was high when there were few sunspots. That link is now explained â�� a shortage of sunspots implies more cosmic rays and cloudy, cool summers. The recent discovery by our team in Copenhagen of the chemical mechanism of cosmic-ray action on cloud formation thus brings to a climax a scientific quest that has lasted two centuries.”

    Before the Nobels are passed out, perhaps it is worth considering the thorny issue of clouds – to briefly recap:

    (1) Clouds cool the Earth by reflecting incoming sunlight.
    (2) Clouds (and water vapor) warm Earth by absorbing heat emitted from the surface and reradiating it in all directions
    (3) Cloud behavior is itself changed by the warming or cooling of Earth.

    You might find these abstracts worth a brief perusal:
    Recent Trends in Arctic Surface, Cloud, and Radiation Properties from Space

    Why it matters: Cosmic ray fluxes are expected to be more noticeable at the poles (Aurora Borealis) due to the shape of Earth’s magnetic field, but polar climate appears to be dominated by the large-scale circulation.
    Rapid Formation of Sulfuric Acid Particles at Near-Atmospheric Conditions

    Why it matters: “The results demonstrate that under laboratory conditions similar to the atmosphere, particle formation occurs at atmospheric H2SO4 concentration levels.” This indicates that no ‘cosmic ray forcing’ is needed to form cloud condensation nuclei.
    Evidence for Large Decadal Variability in the Tropical Mean Radiative Energy Budget

    Why it matters: “We present new evidence from a compilation of over two decades of accurate satellite data that the top-of-atmosphere (TOA) tropical radiative energy budget is much more dynamic and variable than previously thought.” So – where does Svensmark get the 17-35 W/m2 radiative cooling number for clouds?
    The Complex Interaction of Aerosols and Clouds

    This last one is just more on how complex clouds are, particularly when the equally complex issue of aerosols is included.

    As gavin points out in his comment,
    “… Calculations of ‘Cloud radiative forcing’ (which is a specific kind of diagnostic – Cess et al definition) are not the same as the ‘radiative forcing’ in the sense of CO2. It is actually quite difficult to work that out and depends enormously on what kind of environment the extra clouds/aerosols are in (this is one of the big ‘missing steps’).”

    To summarize, this extrapolation of an isolated experimental result to the global planetery system is unjustified (conceptually similar to the c.1900 experiments with infrared light and CO2)

    Comment by Ike Solem — 23 Oct 2006 @ 4:27 PM

  70. re: 67. Yes it formed early enough. Remember that even though the “official” start of the hurricane season is June 1st, it does not really get going climatologically speaking until very late summer. Furthermore, a developing El Nino itself can affect Atlantic hurricane season; it does not have to be peaking. Obviously it is too early for any peer-reviewed papers to come out on this season since it is not officially over. But the El Nino influence on this season has been discussed on NOAA sites.

    Comment by Dan — 23 Oct 2006 @ 6:08 PM

  71. Re 63: My “3rd law” remark was facetious but it has a serious side.

    At some point the scientists have to own their predictions. Post-hoc revisions of every prediction that doesn’t turn out the way you thought it would undermines your credibility. Economists are famous for it, but then that’s a big part of why their’s is the “dismal” science.

    Post-hoc explanations suffer from “early stopping”: you stop digging when you have found a sufficient explanation, but who is to say you’ve incorporated all the relevant phenomena?

    Comment by Crocodile Hunter — 23 Oct 2006 @ 8:16 PM

  72. The lack of a trend in “cosmic ray flux” is presumably based on neutron monitors. What it suggests to me is that the wrong particle is being monitored in this connection. The lack of charge on neutrons implies that they are not involved in ionisation processes in the atmosphere.

    A more direct measure is the sunspot count over 400 years – – the obvious and evident (I don’t want to use the word correlation) similarity with global temperature trends beg the question of a causal relationship.

    The AAstar index – – again is suggestive of trends that reflect changes in global temperatures over the last century. As the theory involves magnetic modulation of the cosmic ray flux, the magnetic record (available over a relatively long period) may be more relevant than neutron monitoring.

    Let’s look at it from a different angle. It is known that there are climate trends that operate over a period of decades. These are powerful climate signals that impact ecologies and temperatures globally. These cycles were first discerned in 1996 in artic fisheries and since in sardine and anchovy abundances in Monterey Bay and in Australian rainfall and flood records. The cycles have been traced back in tree and coral proxies for 400 years – and so are undoubtedly a natural phenomenon that cannot be associated with rises in greenhouse gases.

    Australia now has quite good flood records going back more than 100 years. It has been known for some time that Australia experiences decades long periods of extended drought and, alternatively, decades long periods of flooding. These periods coincide with the temperature record of the last century. The period of rising temperature to the mid 1940′s saw drought, to 1975 was a wet period and then dry again to well now.

    Recent flood analysis suggests that the phenomenon is a result of modulation of both the frequency and intensity of La Nina and El Nino events in the El Nino Southern Oscillation.

    The possible phase reversal of the Pacific Decadal Oscillation since 1998 provides a robustly testable hypothesis. A “cool phase” would result in fewer and less intense El Nino episodes and a consequent fall in the trend line of global temperatures over the coming decades – depending on the relative strength of GHG and the natural background climate cycle climate forcing.

    The decline in solar activity, the decline in temperature since 1998, the slowing of the Great Solar Conveyor Belt (a long range predictor of sunspots), the increase in clouds in recent years may all be connected. There must be a stage at which the accumulation of “coincidence” becomes convincing.

    The cosmic ray flux theory appears to have considerable explanatory power for climate variations over timescales ranging from decades to millennium. If this is not the answer, one will need to be found before anthropogenic influences can be convincingly disentangled from the very powerful background variations.

    Comment by Robert Ellison — 24 Oct 2006 @ 11:24 PM

  73. Re: #72

    The lack of a trend in “cosmic ray flux” is presumably based on neutron monitors…

    A more direct measure is the sunspot count over 400 years

    I know very little about how cosmic ray flux is measured. But I do know that neutrons from space are cosmic rays, sunspots are not. You might therefore make a case that sunspot count as a proxy for cosmic ray flux is more meaningful, but to claim that a proxy (sunspot count) is a more “direct” measure than measurement of *actual cosmic rays* seems rather absurd.

    … the obvious and evident (I don’t want to use the word correlation) similarity with global temperature trends beg the question of a causal relationship.

    Some of the purported similarities are by no means quite so “obvious.” An extremely enlightening paper on this topic can be found here:

    … the decline in temperature since 1998…

    What decline in temperature is that? It doesn’t appear in either the GISS or HADCRU temperature time series — or any other that I’m aware of. In fact, according to GISS, 2005 was the hottest year ever recorded. Using either GISS or HADCRU temperatures, the difference between 1998 and 2005 is not statistically signficant.

    Comment by Grant — 25 Oct 2006 @ 10:50 AM

  74. Re 72

    When we talk about no trend in cosmic ray flux this is related to the measurements starting in the 1950ies. The claimed effect of GHG is also mainly after 1950. If you have a closer look at the sunspots you will detect that there is no trend neither in sunspots nor in the aa index nor in direct cosmic ray flux since 1950. However, the temperature trend since 1950 is quite large. So how do you explain this rise without GHGs?
    Nobody claims that GHGs are the reason of all the temperature trend for the last 400 years.

    Comment by Urs Neu — 25 Oct 2006 @ 12:29 PM

  75. Re 72

    Neutrality is irrelevant; ionization occurs due to collisions. The source cosmic rays are a mix of particles, mainly protons, and the measured neutrons are secondary.

    Comment by Tom Fiddaman — 25 Oct 2006 @ 1:34 PM

  76. Re 74 ‘So how do you explain this rise without GHGs?’

    Urs, to play devils advocate; De Laat and Maurellis ‘Industrial CO2 emissions as a proxy for anthropogenic influence on
    lower tropospheric temperature trends’

    If the economic signatures that DL&M found in temperature series are genuine (and not simply artifacts of, say, the north south split in economic activity) then solar plus aerosol plus direct anthropogenic could be quite a powerfull combination?

    Comment by Charlie T — 25 Oct 2006 @ 3:22 PM

  77. Re #72, among others. I’m having a bit of a conceptual problem in understanding why sunspots are a valid proxy for cosmic ray rates. The CalTech site on cosmic rays linked in #69 says

    “The term “cosmic rays” usually refers to galactic cosmic rays, which originate in sources outside the solar system, distributed throughout our Milky Way galaxy.”

    That certainly seems to imply that most cosmic rays originate outside the solar system. So could we have some numbers, please? What fraction of cosmic rays actually come from the sun? What is the variation between high and low solar rates?

    Furthermore, if I remember my general astronomy correctly, the solar particle flux increases dramatically during solar flares. Flares sometimes hit Earth, with measureable effects such as more widespread aurorae, disruptions to radio & electric power grids, etc. Do we also see increased cloudiness at these times? If not, doesn’t that weigh heavily against any cosmic ray connection to climate?

    Comment by James — 25 Oct 2006 @ 4:46 PM

  78. Wow – this is an active site. At comment No. 72 – I expected that no one
    wuld read it.

    The temperature decline since 1998 – it is perhaps more accurate to say that there was no increase in temperature.

    The difference between 1998 and 2005 is statistically insignificant. One argument goes that 1998 was affected by a strong El Nino whereas 2005 wasn’t and so should be considered the warmer year. The trend line of temperature increase since 1998 is not statistically different from 0.

    If we look only at observed climate phenomenon. What I know most about is flood forecasting in Australia. Australia has quite good flood records going back more than 100 years. It has been known for some time that Australia experiences decades long periods of extended drought and, alternatively, decades long periods of flooding. These periods coincide with the temperature record of the last century. The period of rising temperature to the mid 1940′s saw drought, the period to 1975 was a wet period and then dry again to – well – now. The decline in temperature between 1945 and 1975 indicates that this is a powerful phenomenon with the potential to swamp the GHG signal.

    Recent flood analysis suggests that the phenomenon is a result of long term modulation of both the frequency and intensity La Nina and El Nino events in the El Nino Southern Oscillation.

    The connection between more frequent and more intense El Nino and global temperature is obvious.

    The decades long cyclic climate variation is in principle predictable based on a negative trend of the Pacific Decadal Oscillation (PDO)index. Other empirical evidence supports the idea of a phase shift in the PDO since 1998 – although I am still waiting for a hard rain to fall.

    The connection of solar magnetism to climate is an intriguing idea at this stage.

    The idea seems worth pursuing as a possible explanation for the observed phenomenon – phenomenon that were never adequately explained by GHG forcing alone.

    I am by no means endorsing continued increase in GHG’s in the atmosphere. Even with a moderation of the GHG climate signal, there are still serious problems with that course of action. We may, at best, buy some time.

    In the response to my post – I feel I have recieved some of the respect due to a serious commentator – beats being ignored. Thank you anyone who is interested.

    Comment by Robert Ellison — 25 Oct 2006 @ 6:24 PM

  79. Just a quick addendum on cosmic rays – the idea is that solar magnetism modulates cosmic rays. Not 100% convinced but intriguing nonetheless.

    Comment by Robert Ellison — 25 Oct 2006 @ 6:36 PM

  80. Re #73 What decline in temperature is that?

    Perhaps he googled “Did Global Warming Stop In 1998?”

    Some folks are interpreting data to show either zero increase, or even a slight decrease in global temperatures since 1998.

    Comment by gary — 25 Oct 2006 @ 6:39 PM

  81. Re #77 and “I’m having a bit of a conceptual problem in understanding why sunspots are a valid proxy for cosmic ray rates. The CalTech site on cosmic rays linked in #69 says ‘The term “cosmic rays” usually refers to galactic cosmic rays, which originate in sources outside the solar system, distributed throughout our Milky Way galaxy’.”

    The sources of the cosmic rays are interstellar, the strength of the Earth’s magnetic field determines whether they get through to Earth’s surface or not, and the latter is partly affected by solar activity.


    Comment by Barton Paul Levenson — 26 Oct 2006 @ 8:42 AM

  82. I think it’s apparent that cosmic rays (leading to muons – charged particles, not neutrons anyway) can’t explain the changes of the very late 1900′s. However, a couple of bigger questions are:
    1. Can they affect, or bias, cloud formation?
    2. Is this discussion really about the MWP, with the truly global proxy of C14 production? If that is the case, what are we doing to science by denying it?

    Does this need a lot more study or not?

    Comment by Steve Hemphill — 26 Oct 2006 @ 10:58 PM

  83. I see “The Economist” magazine is printing a favorable blurb about how a new experiment will shown how comic rays alter climate…. see it online at

    I wish the economist allowed user feedback/posts … I’d direct people here.

    Comment by Mike Bauer — 27 Oct 2006 @ 1:21 PM

  84. Re #81: “The sources of the cosmic rays are interstellar, the strength of the Earth’s magnetic field determines whether they get through to Earth’s surface or not, and the latter is partly affected by solar activity.”

    Thanks for the clarification. Still leaves me with a couple of questions, though. First, whether there is any correlation between solar flares and clouds, which it seems there ought to be if the theory is correct.

    Second, the Earth’s magnetic field periodically reverses itself. Presumably there is a period (which I seem to recall reading might be on the order of centuries) in which the field is close to zero, and thus exerts no protective effect. These periods ought to be extraordinarily cloudy, shouldn’t they? If comparatively minor changes produce observed global warming, shouldn’t the larger changes of the reversal periods have produced even greater climate change? Is there any geological record of this?

    Comment by James — 27 Oct 2006 @ 6:32 PM

  85. James, I too would like a fairly definitive answer to your last question. Unfortunately, I doubt that the climate prozy records are sensitive enough to leave mush trace of an event lasting only ‘a few centuries’. Hope somebody can show I am wrong about this…

    Comment by David B. Benson — 27 Oct 2006 @ 6:47 PM

  86. Gavin, Your statement that “Finally, to show that cosmic rays were actually responsible for some part of the recent warming you would need to show that there was actually a decreasing trend in cosmic rays over recent decades” ignores the climate commitment studies that show that surface temperature takes decades to equilibrate to a new level of forcing, and sea level can take a thousand years or more. A cosmic ray reduction from the first part of the century, that is sustained without any further trend in the latter part of the century could explain some part of the recent warming. The argument that you put forward here and also use in “How not to attribute climate change”, that an increasing trend in solar activity or a decreasing trend in cosmic rays in the most recent decades is required is not in accord with the climate commitment literature.

    Comment by Martin Lewitt — 28 Oct 2006 @ 3:46 AM

  87. Is it assumed all variations in GCR energy and frequency at the edge of the earth’s atmosphere are the result of solar effects?

    [Response: On the short (up to millenia?) timescale, I think so. On longer scales you cna invoke modulation by the suns orbit in the galaxy - William]

    Comment by John Lederer — 29 Oct 2006 @ 11:43 PM

  88. Our weekly seminat here at ANU may be topical:

    Jan Veizer (Ottawa-Carleton Geoscience Center, University of Ottawa)


    4:00 pm, Thursday 2nd November
    Jaeger Seminar Room, RSES

    The observed temperature increase of ~ 0.6C over the last century has been attributed (IPCC) by ~ 2/3 to greenhouse gases (GHG) and ~ 1/3 to an increase in solar irradiance (TSI). Such relative attribution reflected the general consensus that no credible amplifier to muted changes in TSI was known. Recently, however, a spate of empirical observations demonstrates that sun-climate connections are apparent in a plethora of high-fidelity climate indicators, suggesting that “solar influence on climate is greater than would be anticipated from radiative forcing estimates” (Hadley Centre technical note 62). The most likely amplification candidates are high-energy particles such as cosmic rays and solar protons, via their potential role in cloud formation. Juxtaposition of empirical records of paleoclimate with proxies for atmospheric CO2 levels vs. celestial (solar and cosmic rays) intensities, across a hierarchy of time scales, indeed favours a reversal of the relative impact of the above climate “drivers”, the last few decades being the focal point of the ongoing controversy. In the above scenario, the celestially modulated planetary energy balance drives the hydrological cycle, with the carbon cycle “piggy-backing” on the water cycle “thermostat”.

    [Response: "and ~ 1/3 to an increase in solar irradiance (TSI)" is wishful thinking. I don't remember that from the TAR. Sadly its site is down now so I can't check - William]

    Comment by C. W. Magee — 30 Oct 2006 @ 1:19 AM

  89. Comment Related to #88


    I believe the reference is the 2007 draft based on what seems to have leaked out so far. Anyway, I wonder if there might be a point here that has been missed. We keep talking about earth being the black body and absorbing the lions share of the incoming radiative solar energy. We have discussed aerosols and water vapor to death and found all to be lacking. The numbers attributed to GHG seem in some sectors to be in question especially in light of the very recent data of the last nine months.

    My question, What if the incoming radiative energy was not all absorbed and reradiated by a terrestrial source. What if the aerosols were to participate in absorbing the incoming radiated solar energy and via convective process to transfer some of the energy to the surrounding air. What if instead of a sperical radiative black body with a diameter of 7726 miles miles you have a black body with a 7926 mile diameter and an average density of 1.48 instead of 1.5? What happens if the aerosol counts of very small aerosols were to increase dramatically, either as hold overs of very small volcanic dust, Kuwaiti oil field fires, forest fires, and possibly now, additional cosmic particles in an era of apparent weakened planetary magnetic field? What happens if the water content of the atmosphere were to increase from an average of say 30% to an average of 50% in addition to the increased aersol density?

    Sorry more questions than I perhaps should be alloted. It seems I have more questions then I have publically avilable resources to pull from.

    Dave Cooke

    Comment by L. David Cooke — 30 Oct 2006 @ 10:45 AM

  90. Re 76

    De Laat and Maurelli is one more example of a study looking for simple correlations without accounting for other influencing factors. They ignore e.g. that 1. the difference of the increase of temperature over land and the ocean will automatically produce a correlation of CO2 emissions and temperature trend since CO2 emissions are almost all over land; 2. CO2 is well mixed in the atmosphere and therefore a correlation to emissions is unlikely; 3. During the time frame they investigate, aerosol emissions have declined over the areas with most intense emissions, possibly leading to an enhanced warming. Aerosol concentrations vary much more regionally than CO2, therefore a link to regional emissions is much more likely to aerosols, not CO2.

    Moreover, they worked with data that have since been corrected (the UAH data), and the difference between surface and lower troposphere temperature trends which they discuss has more ore less vanished.

    Summary: Some outdated speculations…

    Comment by Urs Neu — 1 Nov 2006 @ 3:51 AM

  91. “What happens if…”

    I think most of those things would get measured, and people would take note- esp. a vast increase in atmospheric H2O, which is under continual weather sat observation.

    Comment by C. W. Magee — 1 Nov 2006 @ 5:12 AM

  92. Re 88

    Be aware that Jan Veizer, an emeritus professor, is a profound AGW sceptic, who disputes that there is a significant influence of CO2 on climate, who tells that water vapour is a much more important greenhouse gas, that CO2 reacts on temperature and not vice versa, and more well-known sceptics stuff.

    And remember from my comment 59: Reconstructions (of temperature, CO2, cosmic rays etc.) are so different and have such high uncertainties especially on the multimillion year time scale, that it is no problem to show either a match or a mismatch of the same parameters by choosing specific data sets, tuning the data (within the frame of the uncertainties) and making enough assumptions.

    These remarks are among others related to some work of Veizer. Be aware that much of the cosmic ray-climate connection that Jan Veizer will show, especially on the geological time scale, is the result of an awful lot of picking and tuning (see e.g.

    Unfortunately a lot of geologists (by far not all of course) ignore 1. that geological time scales and the time scales of AGW are way different; 2. that anthropogenic CO2 emissions is a factor that has not existed at the times they are looking at and thus they will logically only find natural variations; and 3. that a new developing factor is not a priori unimportant just because it hasn’t existed before.

    Comment by Urs Neu — 1 Nov 2006 @ 6:35 AM

  93. Re #82 and others. A new paper from GRL. I don’t subscribe, so somebody will have to do the dirty work, The abstract is tantalising:

    GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L21802, doi:10.1029/2006GL027820, 2006

    Different response of clouds to solar input

    Mirela Voiculescu

    Department of Physics, â??Dunarea de Josâ?? University of Galati, Galati, Romania

    Ilya G. Usoskin

    Sodankylä Geophysical Observatory, (Oulu Unit), Oulu, Finland

    Kalevi Mursula

    Department of Physical Science, University of Oulu, Oulu, Finland

    There is evidence that solar activity variations can affect the cloud cover at Earth. However, it is still unclear which solar driver plays the most important role in the cloud formation. Here we use partial correlations to distinguish between the effects of two solar drivers (cosmic rays and the UV irradiance) and the mutual relations between clouds at different altitudes. We find that the solar influence on cloud cover is not uniquely defined by one solar driver, but both seem to play a role depending on the climatic conditions and altitude. In particular, low clouds are mostly affected by UV irradiance over oceans and dry continental areas and by cosmic rays over some mid-high latitude oceanic areas and moist lands with high aerosol concentration. High clouds respond more strongly to cosmic ray variations, especially over oceans and moist continental areas. These results provide observational constraints on related climate models.

    Received 9 August 2006; accepted 27 September 2006; published 1 November 2006.


    Comment by Fergus Brown — 1 Nov 2006 @ 1:13 PM

  94. Percentage of low clouds due to Cosmic Rays:

    WOW…….What a great thread!

    I started several threads, in various science forums, titled ” Lightning Comes from Space” citing Joe Dwyer’s work at FIT on runaway cascade initiation of CG lightning from his observations of X-Rays and Y-Rays.

    Dwyer’s paper:

    Looks like I’ll have to update them with ” Clouds Come from Space Too”

    It will be interesting when we know what exact % of cloud cover is created by CRs.

    If it is high, One of my greatest fears is the Republicans trying to use it to obfuscate the dangers of Green house gases.

    Here are the best numbers I’ve found for the % of low clouds due to Cosmic Rays:

    â??â?¦ cosmic rays. These high-energy particles originate in outer space and in solar flares, and can have a small but significant effect on the weather, increasing the chances of an overcast day by nearly 20 per cent.
    Giles Harrison and David Stephenson from the University of Reading, UK, examined 50 years of solar radiation measurements from sites all over the country, enabling them to calculate daily changes in cloudiness. By comparing this data with neutron counts – a measure of cosmic ray activity – for the same period, the scientists have shown an unambiguous link between cosmic rays and clouds (Proceedings of the Royal Society A, DOI: 10.1098/rspa.2005.1628).
    “The odds of a cloudy day increase by around 20 per cent when the cosmic ray flux is high,” says Harrison, amounting to a few extra days of cloudiness per year.â??

    Thanks for your explanations
    Erich J. Knight

    Comment by Erich J. Knight — 1 Nov 2006 @ 2:33 PM

  95. re 92 #2,

    This is also misattributed by those who link CO2 with temperature. A deep, basic, unproven attribution.

    What if CR’s modify cloudiness and CO2 amplifies convection, increasing albedo? It is within the range of the uncertainty.

    Comment by Steve Hemphill — 1 Nov 2006 @ 10:25 PM

  96. Re 95

    Just two things: 1. The link of CO2 to temperature is not based on reconstructions on the geological time scale, but on solid physics. 2. There is no need to change the frequencies of the ice age cycles for CO2 in order to get a fit to the temperature cycle. However, you have to adjust the frequency of million year cosmic rays cycle considerably to get a match to the temperature.
    The cosmic ray-climate link very often needs artificial adjusting of data to get the match, the CO2-climate link does not.

    Comment by Urs Neu — 2 Nov 2006 @ 3:57 AM

  97. Re #95 and “This is also misattributed by those who link CO2 with temperature. A deep, basic, unproven attribution.
    What if CR’s modify cloudiness and CO2 amplifies convection, increasing albedo? It is within the range of the uncertainty.”

    The attribution of temperature rise to CO2 is not “unproven” at all, it is basic radiation physics. Joseph Fourier speculated on the greenhouse effect in 1824, John Tyndall demonstrated that CO2 absorbs infrared light in 1859, Svante Arrhenius made the first quantitative estimate of global warming under increased CO2 in 1896. The effect of atmospheric CO2 on surface temperatures is so well demonstrated that you would have to be grossly ignorant of radiation physics to deny it.

    And how, precisely, does convection increase the planet’s albedo?

    Comment by Barton Paul Levenson — 2 Nov 2006 @ 5:25 AM

  98. The current Nature has a couple studies, a little off topic concerning sun forcing of climate …….but these measurements do provide an Earth magnetic field history 800,000 years ago and implies stability of geodynamo processes on billion-year timescales.

    Comment by Erich J. Knight — 2 Nov 2006 @ 11:26 AM

  99. The criticism of Svensmark and colleagues’ search for a solar forcing mechanism is perhaps unfair, as there is significant Palaeoclimatic proxy data that links concurrent changes in cosmogenic isotopes (solar forcing evidence) with ice core and other proxy evidence of rapid climatic changes. There is a smoking gun, so to speak. If the smoking gun data is accepted, the question then becomes how the sun likely causes rapid climatic change events, not if the sun causes rapid climatic change events.

    For example the paper: “The role of solar forcing upon climate change” Published 1999.

    “A number of those Holocene climate cooling phases… most likely of a global nature (eg Magney, 1993; van Geel et al, 1996; Alley et al 1997; Stager & Mayewski, 1997) … the cooling phases seem to be part of a millennial-scale climatic cycle operating independent of the glacial-interglacial cycles (which are) forced (perhaps paced) by orbit variations.”

    “… we show here evidence that the variation in solar activity is a cause for the millennial scale climate change.”

    Last 40 kyrs
    Figure 2 in paper. (From data last 40 kyrs)… “conclude that solar forcing of climate, as indicated by high BE10 values, coincided with cold phases of Dansgaar-Oeschger events as shown in O16 records”

    Recent Solar Event
    “Maunder Minimum (1645-1715) “…coincides with one of the coldest phases of the Little Ice Age… (van Geel et al 1998b)

    “Mayewski et al (1997) showed a 1450 yr periodicity in C14 … from tree rings and …from glaciochemicial series (NaCl & Dust) from the GISP2 ice core … believed to reflect changes in polar atmospheric circulation..”

    Comment by William Astley — 4 Nov 2006 @ 12:35 PM

  100. In follow-up to comment 99, that there is significant Palaeoclimatic evidence that links concurrent changes in cosmogenic isotopes (solar forcing evidence) with ice core and other proxy evidence of rapid climatic changes, the following is a paper that discusses the Younger Dryas and Solar Forcing.

    “Reduced solar activity as a trigger for the start of the Younger Dryas?”

    From the paper, “Estimates for the start of the YD all demonstrate a strong and rapid rise of C14 (Cosmogenic isotope that increases when there is decreased solar activity that hence allows increased galactic cosmic rays GCR to strike and interact with the atmosphere.) This change is the largest increase of atmospheric C14 known from the late glacial period and Holocene records.”

    The paper also provides evidence that challenges Broecker’s hypothesis that a sudden stoppage of the thermohaline conveyor, caused the YP. (The paper address the question as to what could have stopped the THC. Also noted has evidence from ocean core data that the THC did not change during the YD.)

    “The main late glacial meltwater pulse found by Fairbanks (1989) is dated 14ka BP, thus at least 1000yrs before the start of the YD (Bard et al., 1996). Maybe, regional meltwater pulses, occurring near locations of the NADW formation, could have perturbed the THC. However, ocean records near the mouth of the St. Lawrence river suggest the opposite, giving evidence of a reduced meltwater outflow from the Laurentide Ice sheet near the start of the YD (de Vernal et al.,1996) Also, the initial drainage of the Baltic ice lake occurred a few hundred years after the start of the YD (Boden et al.,1996). In any case, ice rafting can be excluded as the trigger, since ocean cooling started before the ice rafting occurred (Bond, 1995). Moreover, the ice sheets in N. America, Scandinavia and Iceland fluctuated coherently, thus implying that ice rafting was triggered by climate and not vice versa (Fronval et al., 1995; Bond and Lotti, 1995).

    Comment by William Astley — 4 Nov 2006 @ 6:34 PM

  101. The current Economist has an article:

    Comment by Erich J. Knight — 6 Nov 2006 @ 6:17 PM

  102. My thoughts, from my lab techo point of view, on the Jan Veizer talk mentioned above in comment 88, are here:

    Comment by C. W. Magee — 8 Nov 2006 @ 8:03 AM

  103. RE: #93

    Mr. Brown;

    If the recent data regarding phytoplankton emission of isoprene or DMS affects cloud production is valid. And the indication is that during periods of decreased ICMEs relate to increases in CR. And increases in CR relate to a de-nitrification of the Stratosphere which would offset sodium chloride aersols being lifted to the this region with the possible decrease of atmospheric ozone as a result. And the decrease in ozone would increase the UV energy reaching the phytoplankton on the Sea Surface both killing it, warming it, and increasing the surface salinity. Then may be the issue of cloud formation and the realtionship to CR may be a possibility.

    Occums Razor probably will disallow these observations. To have such a detailed path to follow for cause and effect seems like a logic construction and may not be natural. (I suspect that is part of the reason for the anthropogenic relationship to GW that has been established in the absense of detailed evidence of other drivers.)

    Dave Cooke

    Comment by L. David Cooke — 10 Nov 2006 @ 8:48 AM

  104. Here is the phytoplankton article I saw from the Georgia Institute of Technology Research News :

    Comment by Erich J. Knight — 11 Nov 2006 @ 1:43 AM

  105. The Uppsala Hydrocarbon Depletion Study Group has shown that all the IPCC scenarios on CO2 emission are faulty. There are simply not enough fossile sources in the ground to maintain even the weakest development. I wonder why nobody took the time to look at the amount of oil, gas and coal to back these scenarios? The Uppsala group has contacted IPCC but as far as I know without any answer.

    Comment by Jan Lindström — 16 Nov 2006 @ 1:05 PM

  106. re:105. “The Uppsala Hydrocarbon Depletion Study Group was founded in January 2003. The group has governmental support from the Swedish Energy Agency and industrial support from Lundin Petroleum.”

    Always proceed with extreme caution re: objectivity when citing a study supported directly by an oil company with a clear vested interest.

    Comment by Dan — 16 Nov 2006 @ 2:26 PM

  107. Coal is a fossil fuel, but it is not a “hydrocarbon” and is not part of the Uppsala discussion. Uppsala is, as they say, one of the “peak oil” studies.

    Coal is the big source of near-future CO2 — from old tech dirty coal burning electrical generators, in particular the many dozens of them now committed and funded to be build — these will be used for the next half century.

    Comment by Hank Roberts — 16 Nov 2006 @ 3:24 PM

  108. re 106. The study you are referring to is a Master thesis at Uppsala University. The facts presented can not be turned away referring to Lundin Petrolium. It is easy for anybody to confirm the facts put forward.

    Comment by Jan Lindstrom — 16 Nov 2006 @ 3:38 PM

  109. re: 108. Yes, a Masters Thesis’ “facts” can and absolutely should be “turned away” until it is published and peer-reviewed in a legitimate scientific journal (not a petroleum company journal, web site, or “grey” literature). I can vouch for that from personal experience.

    Comment by Dan — 16 Nov 2006 @ 6:05 PM

  110. Jan — coal is not a hydrocarbon. Uppsala is a ‘peak oil and gas’ study, says so on the website.

    Comment by Hank Roberts — 16 Nov 2006 @ 11:05 PM

  111. A master’s thesis is a type of grey literature, which also undergoes a review process. There is an academic committee for the manuscript as well as an oral defense. There are of course differences in degrees among academic institutions. Usually, no one fact or piece of data is the basis for empirical verification but is aggregated and supported by other data and sources. One of the results from a general survey on grey literature (2004) recommends that grey publishers include a statement on the review process in which their publications undergo.

    Comment by Dominic Farace — 18 Nov 2006 @ 2:11 AM

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