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  1. Think you missed the links to GCR (here, here, here)

    [Response: Thanks! Fixed now. -rasmus]

    Comment by Magnus W — 27 Nov 2007 @ 2:59 AM

  2. Hmmm, this contribution could do with a little polish.

    - The article critiqued isn’t actually quoted (a problem for those not having online access to this AGU journal)
    - Spell checking! (What is ‘buildt’?)
    - The language is not good (‘How could they ignored [sic] that?’; ‘I’d flunked’; similarly in many places) and a bit rambling
    - The claim ‘The paper also offers some incorrect references’ is unintentionally funny as it is followed by an incorrectly written author name, and no actual reference in sight ;-)

    [Response: Link added now. -rasmus]

    - GCR = Galactic Cosmic Rays. Who knew?

    I don’t doubt the validity, but presentation is important. While this is not a peer reviewed journal, what about showing it to a colleague with a red pencil first?

    [Response: Point taken, sorry about that! I was a bit too quick, but it's good to get some feedback. I have fixed the typo and a few of linguistic details. My old English teacher would probably have given me a 'D' for this ;-) -rasmus]

    Comment by Martin Vermeer — 27 Nov 2007 @ 3:06 AM

  3. The study Rasmus Benestad tries to evaluate is

    Scafetta, Nicola, and Bruce J. West, 2007. Phenomenological reconstructions of the solar signature in the Northern Hemisphere surface temperature records since 1600. J. Geophys. Res. – Atm., 112, D24S03, doi:10.1029/2007JD008437, November 3, 2007, and available online http://www.fel.duke.edu/~scafetta/pdf/2007JD008437.pdf

    Earlier studies by the authors are e.g.

    Scafetta, Nicola and Bruce J. West, 2003. Solar flare intermittency and the Earth’s temperature anomalies. Physical Review Letters 90, 248701, June 20, 2003, online http://www.fel.duke.edu/~scafetta/pdf/PRL48701.pdf

    Scafetta, Nicola, and Bruce J. West, 2005. Estimated solar contribution to the global surface warming using the ACRIM TSI satellite composite. Geophys. Res. Lett., 32, L18713, doi:10.1029/2005GL023849, September 28, 2005, online http://www.fel.duke.edu/~scafetta/pdf/2005GL023849.pdf

    Scafetta, Nicola, and Bruce J. West, 2006. Phenomenological solar contribution to the 1900–2000 global surface warming. Geophys. Res. Lett., 33, L05708, doi:10.1029/2005GL025539, March 9, 2006, online http://www.fel.duke.edu/~scafetta/pdf/2005GL025539.pdf

    Scafetta, Nicola, and Bruce J. West, 2006. Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record. Geophys. Res. Lett., 33, L17718, doi:10.1029/2006GL027142, September 15, 2006, online http://www.fel.duke.edu/~scafetta/pdf/2006GL027142.pdf

    Enjoy reading!

    Comment by Timo Hämeranta — 27 Nov 2007 @ 4:15 AM

  4. A [pdf] of the full text we’re discussing here :
    http://www.acrim.com/Reference%20Files/Scafetta%20&%20West_2007JD008437.pdf

    Comment by Charles Muller — 27 Nov 2007 @ 4:32 AM

  5. Work of this nature is important but it needs to be reasonable.

    I also will not be reading this paper (no free access) so I am reluctant to comment but even the diagrams shown here raise some problems.

    One can get some idea of the model being invoked from the implied amplitude and phase delays.

    We have two diagrams (their figure 4) both of which appear to correspond to a simple lumped (thermal)capacity/conductivity system. I note that there is a starting transient (both the input and response are 0 at time 0, and the phase angle and vertical displacement changes with successive cycles).

    Is the reason for the transient explained in the text? (genuine question not rhetorical).

    Such a model has some consequences in that it is a simple low pass filter which would severely attenuate higher frequencies and give them a phase lag of approaching pi/2.

    Now there is some support for this at diurnal and annual timescales over the oceans but less so for the continents.

    Do they give any figure for the time constant or constants they feel explain their effect?

    Too long and the seasons will disappear, too short and the solar cycle will not be attenuated in the temperature record.

    The lumped capacity/conductivity model is but one of several available that might apply to the earth or most importantly the oceans.

    At the ocean surface (well mixed layer) a lumped model may be appropriate, below that a diffusion model (which tends to give a pi/4 phase delay) is believed to be appropriate, and for the deep ocean flows, a more complex transmission line that incorporates the effects of momentum would seem appropriate.

    If we are looking for heat to be returned at a later date in some sort of coherent way only systems that incorporate flow would seem to be likely candidates. Both the lumped and diffusive models smear out the signal (a wiggle in the past will not reproduce that wiggle in the future). Is this what they claim?

    The thermal response of the earth (primarily the oceans) holds an important key to understanding the entire system. It is at least an equal third of the (forcing, long term sensitivity, thermal response) system. It is also the least loved and perhaps the least sexy of the three.

    Analysing the thermal response to accurately known cyclic forcings will give insights into how the oceans behave thermally at various timescales.

    More needs to be done, for instance, what is the amplitude of the 11-ish year solar cycle in the record. Some say it is too attenuated to be found, some say it is big (rather too big perhaps). Which is correct?

    If we do not know the thermal response of the earth well enough to know the size of the solar cycle response how close are we to knowing the relationship between observable (short term) climate sensitivity and the long run sensitivity. Getting the answer to this question wrong has large implications 50 or 100 years out.

    As I understand it, the observable (short term) climate sensitivity is a bit too low to be reasonable and hence much of the thermal excess must be being stored in the oceans. By a bit two low I mean that simple analysis of the 20th century response against long term (CO2) forcings gives a low value to the sensitivity. It is believed that the difference will show up the record in centuries or millennium to come.

    Now it is important to be able to put some limits on the nature of this returned flux. If the paper is saying that stored energy (excess/deficit) is being returned. This must be true but without any knowledge of the timescales and coherence of the returned signal I can not see that it is possible to make any meaningful judgement on such an issue.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 27 Nov 2007 @ 7:27 AM

  6. Timo,

    Thank you for the link, so I will be able to read it after all.

    (Postings crossed)

    Comment by Alexander Harvey — 27 Nov 2007 @ 7:30 AM

  7. #4: Thanks Charles.

    The good news is that the language in the article isn’t so much better… and it went through peer review ;-)

    Comment by Martin Vermeer — 27 Nov 2007 @ 7:44 AM

  8. Now that I am reading the paper some notes.

    Camp & Tung found a 0.18 (+/1.08) K solar cycle signal in the (1959-2004) record. This is the one that I felt seems a little too big. It is not I think quoted by the authors but it is quite recent (May 2007).

    Both 0.1 (+/- .01) K (from this paper) and the above figure can not be correct. The uncertainty in this figure between authors is massive but the values are often precise. One needs ot be cautions.

    Comment by Alexander Harvey — 27 Nov 2007 @ 7:49 AM

  9. Some additional problems of the Scafetta and West (SW) paper:

    SW are proud of the good match of their solar reconstruction and global temperature on the multidecadal time-scale (SW Figure 5). However, this match is without any time lag and thus is strong evidence against a slow system response. If the increase of global temperature since 1970 should be a lagged reaction on the increase of solar activity before 1950 (time lag of maybe about 50 years), such lagged reaction should be detectable for multidecadal variability since 1600, but there isn’t any at all.

    Besides, SW recycle a bunch of tiring old sceptic arguments. They argue e.g. that the CO2 increase during industrialisation might be partly due to a temperature increase. This is funny, since one of the beloved sceptic arguments is that the CO2 increase during ice age cycles lag the temperature increase by more than 600 years. So we will still have to wait a few hundred years to see the CO2 increase due to the temperature increase since the Maunder Minimum (apart from evidence by the isotopic footprint).

    SW completely ignore the third available TSI composite by Dewitte et al. (2005; IRMB), which shows no significant TSI trend in the satellite period. They also ignore that the positive trend of the 11y-cycle minima in the ACRIM data (which they used for their estimations in a previous paper) has almost vanished when including the current minimum (the trend is 10 times weaker now; see http://www.acrim.com/ACRIM%20Composite%20Graphics.htm).

    Comment by Urs Neu — 27 Nov 2007 @ 8:31 AM

  10. I think I am getting a feeling of deja vu here.

    Did we not have another paper trying to extract the time constants and deduce sensitivity a little while back. I think it used autocorrelation.

    Unfortunately the world is a bit more complex than that.

    When the lump models run out to timescales longer than their time constant other mechanisms must be considered to take over. I really wish that the lumped capacity/conductivity model was put in a box marked “dangerous”.

    My quick look at their “time constant”/sensitivity values tells me to consider that the top ~100m of the ocean is well mixed. Which is often regarded to be the case. So this could be a mechanism.

    The question is “is that all there is to it?”.

    Well no, below the well mixed layer diffusion takes over with much longer time constants. Also the deep circulation must be considered with timeconstants of the order of centuries to millenia. Even the mixing of the ocean surface is a complex affair and the depth of the layer is seasonal and dependent on latitude and is unlikely to behave with a single time constant.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 27 Nov 2007 @ 8:32 AM

  11. Sounds like they followed the time-honored tendency of grad students to start from the answer in the back of the book and work backwards until they got it. It appears, however, that their book had the wrong answers in it.
    My questions: Where has all that energy been hanging out for the past 60 years? How do they manage to get a “timed release” of the energy so that it kicks in just in time for the millennium celebration? And most important: Why work so hard to produce such crappy science (e.g. poor reconstructions, no physical understanding…) when we have a model that is physics-based and actually works quite well?

    Comment by Ray Ladbury — 27 Nov 2007 @ 8:52 AM

  12. Can anyone follow the production of T(MANN03) etc.

    Rearranging gives:

    ((T18-T17)+(T19-T17))/2 = ((T18-T17)+((T19-T18)+(T18-T17)))/2

    = ((T19-T18)+ 2*(T18-T17))/2

    = (T19 + T18)/2 – T17

    which is the average of (average 19thC + average of 18thC) – the average of 17thC (temperatures)

    Far too many averages for my liking also the distance from the temporal average of the 17thC to the temporal average of the temporal averages of the 18thC and 19thC is 150 years not 100 years.

    I.E. if they must do this should there not be a 3 not a 2 in the denominator?

    Try it with a 1K/Century linear slope from 1610-1910.

    Apply their formula and you get 1.5K/Century:

    (1-0)/2 = 0.5 (T17)
    (2-1)/2 = 1.5 (T18)
    (3-2)/2 = 2.5 (T19)

    ((1.5-0.5)+(2.5-0.5))/2 = 3/2 = 1.5

    If this is really is the case I have to ask when papers get reviewed does anyone check the equations?

    Comment by Alexander Harvey — 27 Nov 2007 @ 9:50 AM

  13. But it is unclear why the temperature then flattened out and even dropped a little between 1940-1970 at the time when it really should have increased fastest

    The reason is one that realclimate keeps pushing on the CO2/temperature correlation problem.

    1940-1970 the correlation between CO2 and temperature is not positively correlated, and yet realclimate doesn’t view this as a problem.

    However, if an alternative explanation has the same issue, then its a major flaw.

    Is is it that rasmus in his original post things that pollution causing the temperatures to drop 1940-1970 isn’t a good explanation? If so, if he would let me know, I’d like to have a realclimate statement that there’s a major flaw in AGW.

    Nick

    [Response: Arrggh! The whole point of the 'mainstream' view is that you are not going to get very far with simple one-factor correlations. It doesn't work for solar, and it doesn't work for CO2 either - too many of the forcings are correlated. You absolutely need to use all major forcings before you can do an attribution. When you do that, GHGs are very likely responsible for the rise in recent decades. - gavin]

    Comment by Nick — 27 Nov 2007 @ 10:25 AM

  14. PMOD link is broken. I assume it should point here (www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant) rather

    Comment by James Davey — 27 Nov 2007 @ 10:32 AM

  15. Dear Alexander, it’s good when you direct attention to the oceans.

    Please see:

    Wunsch, Carl, 2007. The Past and Future Ocean Circulation From a Contemporary Perspective. Chapter in Schmittner, Andreas, John Chiang, Sidney Hemmings, Editors, 2007. Ocean Circulation: Mechanisms and Impacts. AGU Geophysical Monograph Series Vol. 173, 2007, online http://ocean.mit.edu/~cwunsch/papersonline/present_pastocean_rev_2april.pdf

    Abstract

    Meridional overturning of the ocean, particularly the North Atlantic, is commonly invoked as the “trigger” and major cause of global climate change in a series of stories based upon a very simplified view of the circulation (a “conveyor belt”). Observational and computational progress in physical oceanography, however, over the last 30 years has rendered obsolete the old idea that the fluid ocean is a slowly changing, passive, almost geological system. Instead, it is a dynamically active, essentially turbulent fluid, in which large-scale tracer patterns arise from active turbulence and do not necessarily imply domination of the physics and climate system by large-scale flow fields. To the contrary, oceanic kinetic energy is dominated by the time and space-varying components. The complexity of the resulting fluid pathways is an essential part of any zero-order description of the system. Thus general circulation models are the essential tool for understanding past, present and future climate states. Quantification of the likely major errors in using oversimplified models with inadequate turbulence closures and undersampled data becomes the main issue. Determining the past and future circulations is not easy, but hiding the difficulties is not a viable option.

    ….

    Well, as far as I can see, before we are able to correctly model the oceans we are unable to forecast (almost) anything.

    Actually, honest modelers have already admitted that 30, 50 or 100 yr forecasts/projections are too uncertain and have no practical value.

    Please see e.g.

    Cox, Peter M., and David B. Stephenson, 2007. A Changing Climate for Prediction. Science Perspective Vol. 317, No 5835, pp. 207-208, July 13, 2007

    Stainforth, David A., M.R. Allen, E.R. Tredger, and L.A. Smith, 2007. Confidence, uncertainty and decision-support relevance in climate predictions. Philosophical Transactions of the Royal Society A Vol. 365, No 1857, pp. 2145-2161, August 15, 2007

    Collins, Matthew, 2007. Ensembles and probabilities: a new era in the prediction of climate change. Philosophical Transactions of the Royal Society A Vol. 365, No 1857, pp. 1957-1970, August 15, 2007, online http://www.journals.royalsoc.ac.uk/content/u0106636v6g14764/fulltext.pdf>

    Extract:

    “…Model imperfections, coupled with fundamental limitations on the initial-value prediction of chaotic weather and the unknown path that society may take in terms of future emissions of greenhouse gases, imply that it is not possible to be certain about future climate…”

    Even the IPCC admits:

    ”the future is inherently uncertain” (IPCC AR4 2007 WGIII SPM, last sentence)

    ….

    Well, when we discuss about solar influence, which has been flat for the last two or so decades, I’m pondering inertia in the oceans. I recall seeing an estimation of 10 years lag time in the mixed layer. Any confirmation?

    If correct, we may have one possible explanation (among others) to current non-warming of surface and oceans, despite CO2 increase (?).

    Another explanation we have in the study

    Smith, Doug M., Stephen Cusack, Andrew W. Colman, Chris K. Folland, Glen R. Harris, and James M. Murphy, 2007. Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model. Science Vol. 317, No 5839, pp. 796-799, August 10, 2007, online http://www.precaution.org/lib/warmer_after_2009.070810.pdf

    [Response: Lack of absolute certainty is not the same as no knowledge. All scientific knowledge is preliminary and not absolutely certain, so by your implication, we know nothing useful about anything. I find it odd that you only apply this heuristic to climate change. - gavin]

    Comment by Timo Hämeranta — 27 Nov 2007 @ 12:02 PM

  16. Check out http://www.co2ticker.com to see co2 emissions BY THE SECOND and compare different countries co2 emissions .

    Comment by jonny — 27 Nov 2007 @ 12:10 PM

  17. rasmus, the point on the “upper limit” had to do with the study being sun-centric. In other words, S&W don’t put much emphasis of volcanoes, pre-industrial anthropogenic, and possible other natural causes for pre-industruial climate variability. Not much to my liking, but that’s life. I did not like your point on S&W comments about the sun-CO2 feedback relationship. It should be clear the sun isn’t doing anything to CO2, the temperature change (generally centered in orbital variations) is. Simple gas proportionality inversely related to temperature and we reproduce a feedback. Of course, the sun isn’t digging up buried CO2. S&W specifically note atmosphere-ocean gas exchange. However, S&W is also trying to get more CO2 feedback than is possible. S&W should go over the CO2-temperature response at http://www.springerlink.com/content/9q2hwxrhr3cm8g87/?p=6ee1c184f37d4955a354d64157c3a084&pi=11 (and since solar is a minimal impact next to GHG, and we’re not yet even at 1 C, you can’t get the feedback being discussed- not to mention what we know about the Suess Effect and known fossil fuel emissions)

    Secondly, if we accept figure 5b from S&W, I have a hard time accepting the “thermal lag” argument. We run into the same problem repeated here often- if the lag was so huge, we expect the rate of warming to drop over time as the ocean adjusts to the level of forcing, but instead we are seeing the opposite. Perhaps a lag over years to decades, but 50 years and still no signal of the decline? And then we reproduce a graph with direct correlation with no lag?

    A few other things
    - Mann et al. does not “get rid” of a MWP and LIA
    - “weaker TSI forcing would imply the presence of a stronger climatic feedback to TSI variation and/or a stronger climate sensitivity to other solar changes” – What about non-solar changes? True, a larger change from unmodified causes means a more-sensitive climate system but here there is no reason to necessitate unmodified causes. The logic could also apply to GHG’s.
    - Your points still remain: stratosphere cooling? PMOD? ERBS/ERBE, GCR, the aa-index, 10.7cm flux, solar cycle length, sunspot number, etc showing no trend…Silliness

    Comment by Chris C — 27 Nov 2007 @ 12:20 PM

  18. Re: Ray Ladbury “Why work so hard to produce such crappy science?”

    Odds are they’re being rewarded for their tireless contributions somehow, along with the editors of the crappy journals… [edit]

    [Response: But JGR-A is not, in general, a crappy journal. Where there is some controversy, editors often like to lean over backward to let things into print so they can be discussed out in the open. This flaws in this paper should have been caught in review, though. Taken together with other deeply flawed papers that S&W have been able to publish in AGU journals, it does seem to me that a pattern is emerging which suggests some breakdown of the review process at AGU. [edit] –raypierre]

    I’m a rank amateur where the study of science is concerned, so RealClimate continually amazes me with the sheer flim-flammery of some people who call themselves scientists, and some journals which call themselves scientific. Silly me, I used to think “peer-reviewed” meant something.

    Are there any conventions regarding financial disclosure for scientific journals? Just wondering. Enhanced transparency could restore the reputation and vitality of scientific publishing. Such standards could take the form of voluntary protocols, certified by an independent organization as is “Fair Trade” coffee. Maybe that’s just a con game as well, but at least I (the coffee purchaser) can distinguish between coffee vendors who at least care about seeming to care, and those who clearly don’t.

    Comment by Daniel C. Goodwin — 27 Nov 2007 @ 12:22 PM

  19. With respect, I have read many excellent articles on this site followed by interesting discussions.

    The content of this article is interesting, however the presentation is so poor—well it’s hard to believe we are reading it a realclimate.org

    The article needs a rewrite from top to bottom.

    [Response: I'm sorry about this. I have re-read the post, and made slight improvements (removed 'and's and hopefully improved the grammar). But that aside, I think the points are clear. Is it 'contaminated' by my Norwegian, do you think? -rasmus]

    Comment by Charlie Webster — 27 Nov 2007 @ 12:28 PM

  20. Rasmus or someone else here, can you give examples of papers that discuss the impact of solar variation over the last 400 years that you do like?

    Comment by Robert A. Rohde — 27 Nov 2007 @ 12:38 PM

  21. I couldn’t find other way to address this blog’s contributors so I will try here.

    What do you think about the recent Oxfam study, which states that the major climate disasters have multiplied by four due to the global warming? Does it have any credibility? Is it serious? Is it a gross overstatement of something that is happening? What do you believe on that matter?

    Sorry for my english, and thank you for your time

    :)

    Comment by Joao Vasco — 27 Nov 2007 @ 12:53 PM

  22. Timo, you are once again falling victim to the fallacy that because we don’t understand everything, we understand nothing. Some results remain robust over the entire possible range of likely changes in ocean circulation. What is more, those arguing for complacency fail to understand that most of the risk uncertainty is on the upside. By all means, we need to keep studying the problem, but we need to be working on mitigation in parallel with those efforts. Not to do so when dealing with a physical system with large and ill constrained positive feedbacks is negligent to the degree of criminality.

    Comment by Ray Ladbury — 27 Nov 2007 @ 12:56 PM

  23. Charlie, re: 19. I think you are being entirely too harsh. There are gramatical errors and organization could be improved, but the points Rasmus makes, he makes quite clearly. Sometimes it’s kind of fun to go along with the experts as they annotate their reaction to an article in quasi-real time.

    Comment by Ray Ladbury — 27 Nov 2007 @ 12:59 PM

  24. Some first comments.

    Rasmus : But it is unclear why the temperature then flattened out and even dropped a little between 1940-1970 at the time when it really should have increased fastest.

    Could aerosol direct and indirect effects explain that ? (The diminution of ongoing SW counterbalancing the delayed effect of 1900-40 warming)

    [Response: Yes, it think so,. But if the relaxation time is long and the solar forcing the dominant driver, no.. -rasmus]

    *

    Rasmus : The problem with the UV-explanation (ii) is that the stratosphere has been cooling – some of which is due to the ozone depletion. How could they ignored that?

    First, stratospheric T 100-50 hPa has a global cooling trend for past 50 years (see Sterin thereafter for example), but how could we explain that if TSI has no change at all, particularly since 1980 (PMOD composite) ? The usual anwsers are : O3 depletion and CO2 forcing. But in this case, is the stratospheric trend of any help to infer a solar UV or TSI trend, if O3 and CO2 are the main drivers ?
    http://cdiac.ornl.gov/trends/temp/sterin/steringrap.html

    [Response: One proposed mechanism for how the solar signal may be amplified is that solar UV alters the density/temperatures in the stratosphere, which subsequently affect planetary wave propagation. This may have an effect of the redistribution of heat, and thus lead to a warming response near the surface. One would expect a warming of the stratosphere with increased solar activity levels (increased absorption of UV). But if ozone-depletion takes place, this will counter this mechanism, and since the stratosphere has cooled, seems to be the strongest effect (well increased GHGs also play a role).-rasmus]

    Second, we should precise which level of stratosphere and which latitude are concerned. I read for example in ML Chanin 2006 or Labitzke 2006 that stratospheric response to solar maxima minus minima is not a univocal warming trend. See special issue of Space Science Reviews, recently published by Springer in Space Science Series ISSI 2007 :
    http://www.ingentaconnect.com/content/klu/spac/2006/00000125/f0040001

    [Response: I think this depends where you are looking. -rasmus]

    *

    #9 Urs In the figure 5, the 1900-2000 period is the sole to exhibit a constant rising trend for TSI proxies. So, in previous periods, the long term response could be cancelled by short term variations (at least theoretically). Anyway, I fastly read S&W paper but I don’t find the 50 yrs time lag you mention. Could you precise ?

    *

    More generally, all TSI reconstructions (see Lockwood et Frohlich 2007, Lean et Wang 2005, Solanki et Krivova 2006, Beer, Vonmoos et Muscheler 2006, etc.) agree on one point : the Sun is more active on 1960-2000 than in 1900-1940. And more active for 1900-2000 that for past two centuries, at least if TSI reconstruction from magnetic proxies (open flux) are correct.
    The fact that there’s no trend for 1980-present (or a small decrease) should not dismiss this evidence : the 20th Century global warming seems to correlate with a global brightening of our star. Astrophysician and others work on the physical explanation and evaluation of this correlation (UV-ozone and stato-tropo circulation, with QBO and BDC, effect on GCR and nebulosity, etc.). That’s the normal job for science, the same is done for CO2 effects on climate.

    [Response: Actually,. there is little trend from the end of the 1950s. -rasmus]

    Comment by Charles Muller — 27 Nov 2007 @ 1:24 PM

  25. Re #s 19/23: I agree with Ray. As long as the points are made clearly (which they were in this case), perfect English grammar isn’t a necessity. We want to encourage non-native speakers of English, and unfortunate remarks like Charlie’s have the opposite effect.

    [Response: Having said that, we should have done a grammar check before posting. - gavin]

    Comment by Steve Bloom — 27 Nov 2007 @ 1:43 PM

  26. [Response: Arrggh! The whole point of the ‘mainstream’ view is that you are not going to get very far with simple one-factor correlations. It doesn’t work for solar, and it doesn’t work for CO2 either - too many of the forcings are correlated. You absolutely need to use all major forcings before you can do an attribution. When you do that, GHGs are very likely responsible for the rise in recent decades. - gavin]

    Quite right. However, rasmus uses this argument to say that S&W are wrong.

    I’ll post the sentence again

    But it is unclear why the temperature then flattened out and even dropped a little between 1940-1970 at the time when it really should have increased fastest.

    [Response: I think we all agree and it's not really unclear to me... As Gavin says, there are several forcings. But if you play along with S&W that (i) the relaxation time is long and (ii) that the solar forcing is the dominant forcing, then it's hard to explain. S&W do not discuss this or why different forcings should have different relaxation times. -rasmus]

    Let me put this in CO2 terms.

    But it is unclear why the temperature decreased during the 1940-1970 period at a time of rising CO2.

    This is identical logic used by rasmus to say that S&W are wrong. If you apply the same standard and level of scientific thought, you come to the conclusion that AGW is wrong.

    One could argue that something else also happened then

    Exactly. The arguments that you apply to the correlation being negative in this period, also apply to the question of solar.

    Put it this way.

    What evidence do you have that your claim of polution 1940-1940 does not apply to S&W solar explainations?

    None.

    That’s why the original article by rasmus is deeply deeply flawed.

    [Response: Don't agree, because you misunderstood my point. This merely shows that solar forcing is not the main driver (as S&W presume) and the additional variations suggest a shorter relaxation time than S&W suggest, as they imply that a long relaxation time is means that the present warming is part of a recovery from increased solar activity in the past. -rasmus]

    Nick

    [Response: Rasmus can defend himself, but S&W have started with the assumption that solar is the only important driver, therefore the criticism made is justified. Rasmus is not doing the opposite (i.e. assuming that CO2 is the only driver) therefore your equivalency is in error. - gavin]

    Comment by nick — 27 Nov 2007 @ 1:47 PM

  27. I’ve quoted directly from rasmus’s post and he taken the view that you can use a one-factor model for solar.

    To then come back and say that he isn’t because he isn’t assuming that CO2 is the only driver is distorting what I’ve said.

    I’ll spell it out again to make it clear.

    Rasmus says in the article that 1940-1970 there is not a good fit of temperature with solar, contradicting the model which predicts a rise.

    The implication here is that because the model (single factor) does not fit then the premise of a large solar component is falsified.

    The problem is back on the single factor model which doesn’t work for CO2 either. You, as you rightly point out, need more factors.

    It is at this point that the article goes wrong. As you Gavin well know, the single factor CO2 model doesn’t work 1940-1970 because of the factor of polution.

    Introduce that and there is clear explaination of why 1940-1970 shows a temperature drop in spite of a solar increase.

    What rasmus is arguing is that you can use pollution for a CO2 model, but you can’t use it for a solar model.

    [Response: Actually, I'm saying you can't have a long relaxation time and a dominant solar driver. The clue to S&W's argument is that precisely this combination is used to explain the recent global warming. I also say that the climate responds to many forcings (GHGs, aerosols, volcanoes, solar, etc), but there are also internal variations. -rasmus]

    He should have said that the 1940-1970 drop is expected from a solar model, for the same reason as there is a drop 1940-1970 from a CO2 model.

    Nick

    [Response: We don't appear to be communicating. S&W assume a one factor solar model. Rasmus points out (correctly) that this fails a number of tests. No one is assuming a one factor CO2 model. There is only one correct model which is to take all forcings together. Criticising S&W for not doing so is perfectly fair game. - gavin]

    Comment by nick — 27 Nov 2007 @ 2:16 PM

  28. Charles, You seem to be saying, “Let’s forget the last 20 years. Then we can just assume it’s all due to the Sun.” I don’t think that’s going to work. The fact of the matter is that you can’t consider factors in isolation, and if you don’t include the added warming due to greenhouse gasses, you don’t match the trends. What we have is a situation where the sun gets warmer and the climate gets warmer. Then the Sun cools and the climate still gets warmer. Hmm. That ought to tell you something.

    Comment by Ray Ladbury — 27 Nov 2007 @ 2:35 PM

  29. Gavin – I can not find anything in the paper suggesting that S&W assume solar to be “the only important driver”. And even if they were – how does that contradict the point nick made? Even with solar being the most important driver, the standard explanations for cooling in the mid 20th would still apply, wouldn’t they?

    [Response: The assumption is built in to their 'model'. If they wanted to include other factors - aerosols, GHGs etc. they could have done so. The 'real' explanation is a combination of aerosol forcing, combined with some internal variability - neither of these factors are accounted for here. - gavin]

    Comment by henning — 27 Nov 2007 @ 2:46 PM

  30. Nick,

    Further to Gavin’s point, Rasmus has only demonstrated that there is an serious inconsistency in S&W’s premise that variation in solar activity is the lone forcing of climate change. Namely, it requires near uniform response times, which is manifestly at odds with even their, (questionable), data. See post #9 for more on this. It is a perfectly valid point and totally inapplicable to the mainstream understanding of the system, which, as indicated by Gavin, is nothing if not multi-causal. I sense there is a question underlying this accusation, which IMOHO, would probably be a better approach.

    Comment by Majorajam — 27 Nov 2007 @ 3:03 PM

  31. But as I understand it, the whole point of their model is a (unique?) approach to quantify solar influence on climate variability based on different proxy studies – they don’t try to explain the recent decadal temperatures in detail. They’re talking at some considerable length about anthropogenic influences in the text and state, that solar merely contributes to recent warming. (And if you pick MBH rather than Moberg, that contribution is rather small).

    [Response: That might be what they are trying to do. But it is flawed because other factors correlate with solar over these timescales and the role of unforced noise is not quantified. Unique is not the problem. -gavin]

    Comment by henning — 27 Nov 2007 @ 3:11 PM

  32. Okay, so the big issue here is the importance of just focusing on the “solar issue”
    From a non-expert view, can you come up with at least a ball park ratio of forcing?

    If solar output=1
    Then aerosols= 0.2?
    And CO2=0.4?

    Any way to put a value on what is most important?

    [Response: It depends on what period you are talking about. For the twentieth century, normalising to solar=1, you would get CO2=8 (that is eight times solar, not 0.8), other GHGs=5, aerosols=-4 etc. In the pre-industrial period, solar=volcanic=1 (roughly). - gavin]

    Comment by Joe — 27 Nov 2007 @ 3:30 PM

  33. Re # 18 Daniel C. Goodwin “RealClimate continually amazes me with the sheer flim-flammery of some people who call themselves scientists, and some journals which call themselves scientific. Silly me, I used to think “peer-reviewed” meant something.”

    Are you referring to the RC contributors (none of whom, to the best of my knowledge, receive funding from the power industry, nor consult for the power industry), or the authors of papers critiqued by the RC contributors? Please clarify!

    As for peer review, it means only that reasonably qualified scientists examined the manuscript and recommended changes to improve the paper, or recommended that the paper be rejected; the journal editor has to make a determination about the merits of the paper based largely, but not entirely on the reviewers’ comments (the editor has some discretion in deciding to accept or reject – his/her reputation as an editor, and the reputation of the journal, depend on sound editorial judgments).

    The quality of peer review varies with the individual reviewers, some of whom put tremendous effort into a review (possibly even checking the math in equations, checking computer code, etc), whereas others may not put much effort at all into their review (I’ve certainly had reviews of my papers that indicated to me that the person didn’t carefully read, or simply didn’t understand, my manuscript). This is why, as others on this site have repeatedly warned, you can’t put too much stock into any single paper – it needs to be viewed in the context of the wider body of literature on the subject and the work currently in progress (this is why scientists go to conferences to hear about research being conducted). Scientists doing research and publishing in a given field will have more, or less, confidence in the findings in a new paper depending on their particular knowledge and experience. Publication in a peer reviewed journal is just the starting point for research to make an impact on the scientific community – it is not the final word.

    As for your question, “Are there any conventions regarding financial disclosure for scientific journals?” – it depends. Here are the ethical guidelines for AGU journals:

    http://www.agu.org/pubs/pubs_guidelines.html

    I see no mention of financial conflict of interest disclosure (though, most funding agencies require acknowledgment of funding source in any publication). However, I am not surprised – this has only recently become an issue in the medical literature, because of revelations of bias associated with corporate (e.g, drug companies) support of clinical research. Certainly, if a climate scientist is supported by an oil company or other source that could be considered to have a stake in the research findings, this should be disclosed in the acknowledgments section of the paper. Is this always done? I don’t know.

    [Response: To, blogs (like RC) may play an important role, as papers get discussed. Poor papers will be torn apart, and when authors know that they risk their paper being scrutinized and criticized, they will hopefully take more care to check their analysis. -rasmus]

    Comment by Chuck Booth — 27 Nov 2007 @ 3:41 PM

  34. I think some of the comments are misconstruing the work of S&W.

    Yes, the only forcing in their model is solar variability. But their purpose is not to say that the sun explains all behavior, but rather to characterize how much variation might be explained by solar forcing.

    For example, from page 7:

    The Sun might have contributed at most ~0.35K during the preindustrial era (1600–1900) and ~0.4 K from 1900 to 2005. Thus the Sun could have contributed roughly 4/8 = 50% of the global NH surface warming that occurred from 1900 to 2005. Since 1950 the Sun might have contributed ~0.05K (0.5/6 = 8% of the warming) using LEAN2000, or ~0.15K (1.5/6 = 25% of the warming) using WANG2005.

    Using the preindustrial period to calibrate the impact of solar forcing is quite reasonable, given the high apparent correlations between solar variation parameters and temperature reconstructions such as Moberg’s. Finding that some fraction (e.g. 8-25%) of the warming post-1950 might be explained as a residual solar effect, isn’t even entirely unexpected and doesn’t appear to challenge the consensus that most of the post-1950 warming is anthropogenic.

    Some of the criticisms being made here are legitimate (e.g. ACRIM/PMOD), but a number of comments seem to spuriously assume that they were attempting to explain all of 20th century warming. Their model certainly doesn’t explain all of the features of the temperature record, but since it was never their claim to have done so, such criticisms seem misplaced.

    S&W still believe that GHG are major climate forcing and that anthropogenic effects are responsible for most of the recent (post-1950) warming.

    [Response: The series of S&W papers have many assumptions that always increase the attribution to solar. I doubt that I am alone in perceiving a desire to make the number as big as possible. It is not that the answer is zero, but the likely answer (roughly 10%-20% of 20th Century warming, more like 0% for post 1980) never appears to be bracketed by their error bars. Aren't you curious why not? - gavin]

    Comment by Robert A. Rohde — 27 Nov 2007 @ 4:17 PM

  35. Joao Vasco (29) — Your English is quite good, but I fear that ‘major climate disasters’ is subject to misinterpretation. To me, the spread of the Sahara Desert south into the Sahel might be called a major climate disaster, as are the devastations of the world’s tropical rain forests. These are caused by humans, although climate change may also play a role in the expansion of the Sahara Desert.

    If you are referring instead to extreme weather events, then yes, global warming is thought to make such more likely. I don’t know about the factor of four, which seems too high to me.

    I’m not sure I have answered your questions (and anyway, I am an amateur here). If not, please rephrase and I (or someone) will try again.

    Comment by David B. Benson — 27 Nov 2007 @ 4:51 PM

  36. #28 Hank, I don’t forget at all the past 20 years and it would be very surprising that solar forcing explains all the modern GW. In fact, I’m not much interested by “correlation game” ad attribution-detection with ad hoc parametrization, neither for S&W here nor for AR4 models. Ingram 2006 shows interestingly in his paper that 11 years smoothing of T and Fs give a very good correlation (but very bad for CO2) and inversely for a 8 yrs smoothing. More broadly, many signals of XXth century climatologies are degenerated (the better illustration of that : 23 models perfectly match the T curve 1900-2000… but with different parametrizations, different forcings, different simulations of nebulosity/insolation, different complexities… so we must suppose it’s not so difficult to reproduce the modest 0,76 °C slope for 1850-99 / 2005 — and to reproduce it uncorrectly).

    Ingram 2006 :
    http://www.ingentaconnect.com/content/klu/spac/2006/00000125/F0040001/00009057

    The physical question is : do we fully understand solar effects on climate and do we fully implement the mechanisms in models ? I guess the answer is no and no, as Haigh pointed it in the introduction of the special issue of SSR I mention above. So, there’s no reason to believe attribuction-detection of climatologies will not evolve in the future, as well as climate sensitivity for 2xCO2.

    Comment by Charles Muller — 27 Nov 2007 @ 4:55 PM

  37. An earlier try at something like this was Soon and Baliunas, Ap J 472 (1996) 472. Failed, and was commened on in the TAR

    Comment by Eli Rabett — 27 Nov 2007 @ 5:25 PM

  38. The solar expert Leif Svalgaard had some interesting postings on Tamino’s blog arguing for a floor in solar activity at sunspot minimum, i.e. that solar forcing at the Maunder minimun is about equal to today’s. He has some interesting papers on his website, see http://www.leif.org/research/

    Back to the S&W paper, could anyone give a reason for why the two “doctored” TSI curves (which are equal after 1950) show a difference in modelled temperature for the last decade increasing to 0.1 degree (figure 6b)?

    Comment by Erik Hammerstad — 27 Nov 2007 @ 6:01 PM

  39. Re #38: More than that, Erik, IIRC he argues that irradiance hasn’t varied at all (and will be presenting at AGU to that effect). In addition, he stated that the latest S+W paper is invalid on its face because the data sets upon which it’s based are no longer deemed valid. If nobody beats me to it, I’ll see if I can pull out his specific remarks later.

    Comment by Steve Bloom — 27 Nov 2007 @ 7:32 PM

  40. Joao,

    I do not no much about this study but I can say that it was treated cautiously on BBC radio news:

    I can include the following extract from the original report:

    http://www.preventionweb.net/globalplatform/first-session/docs/session_docs/ISDR_GP_2007_3.pdf

    Note 1

    By analysing the EM-DAT database, it is possible to reveal patterns and trends in disaster occurrence and loss globally, comparing countries, comparing time periods and comparing hazard types. The EM-DAT database contains data entries from 1900 through to the present, and registers events as disasters if they produced 10 or more deaths, 100 or more affected people, or where a state of emergency was declared or a call for international assistance was made. The data has a global level of observation and a national scale of resolution. The data is gathered from UN agencies, government sources, IFRC, insurance sources, press and others and is maintained by CRED. EM DAT has a number of data fields including, numbers killed and affected, and economic losses.

    The BBC implied that this statement represents what the authors defined as a disaster.

    Two of these:

    “a state of emergency was declared” or “a call for international assistance was made”

    the BBC noted that these are political decisions not objective measures.

    I hope this helps you.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 27 Nov 2007 @ 8:22 PM

  41. Question- can you pull the difference between 1900-1950 and 1950-2000 from the S&W2007 data alone because it is pretty well established solar was more important earlier on, with anthropogenic dominating in the second half of the century. But the period of interest in the paper (the 50% number) is from 1900. Still an overestimate, but the number is higher when you include earlier in the century.

    Comment by Chris C — 27 Nov 2007 @ 8:30 PM

  42. Joao,

    Here is the Oxfam page that contians the link:

    http://www.oxfam.org.uk/resources/policy/climate_change/bp108_weather_alert.html

    and the headline quote:

    The total number of natural disasters has quadrupled in the last two decades – most of them floods, cyclones, and storms.

    Comment by Alexander Harvey — 27 Nov 2007 @ 8:37 PM

  43. Please excuse my harsh comments on the writing and thanks for the edits. It’s a very interesting piece—and yes I would prefer to have imperfect prose than no prose.

    [Response: ..and I should take more time to check the prose of my own post. -rasmus]

    Comment by Charlie Webster — 28 Nov 2007 @ 1:03 AM

  44. Re 15 To Gavin’s response:

    Gavin, you do know I critizise unjustified certainty and we both know Climatology is all about probabilities and uncertainties, even unknowns, only.

    It’s strange how scientists interested in probabilities are annoyed about scientists interested in uncertainties (to put it nicely).

    Re 22 Ray:

    Additionally to above, too often I see Logical Fallacies when the cause identified actually is only a (tiny) part of a whole gengre of causes.

    Re 33 Rasmus’ response

    Rasmus writes “Poor papers will be torn apart, and when authors know that they risk their paper being scrutinized and criticized, they will hopefully take more care to check their analysis”

    Well, if you behave otherwise, i.e. rely the studies you like, and don’t rely the studies you don’t like, you are no scientists.

    Scepticism, criticism, validation and replication are the only means Science can survive.

    [Response: Scientific debate and discussion is important - actually essential. We can at least agree on that. -rasmus]

    ….

    Well, no comments so far about ocean inertia.

    When the sun has been exceptionally active and 80 % of solar heating sinks into the oceans, in recent years I have several times inquired whether the current warming were a coincidence of numerous variations, oscillations and cycles originating from the oceans?

    But, unfortunately, as Carl Wunsch has pointed, the oceans are a similar nonlinear, chaotic and turbulent system as the atmosphere.

    Like it or not, but so far I see more uncertainties than probabilities.

    Comment by Timo Hämeranta — 28 Nov 2007 @ 2:33 AM

  45. #38 Erik Hammerstad,

    From S&W para 31:
    “Figure 6 shows the comparison between the two NH
    temperature reconstructions shown in Figure 1 and the
    phenomenological solar temperature signatures obtained
    with the TSI proxy reconstructions corrected with the
    ACRIM TSI satellite composite since 1980, as shown in
    Figure 3.

    By assuming ACRIM, the solar activity has an
    increasing trend during the second half of the 20th century.”

    That’s why there’s a difference in modelled temperature for the last decade between 5b & 6b.

    Comment by CobblyWorlds — 28 Nov 2007 @ 3:09 AM

  46. At 27, Rasmus writes
    [Response: Actually, I’m saying you can’t have a long relaxation time and a dominant solar driver. The clue to S&W’s argument is that precisely this combination is used to explain the recent global warming. I also say that the climate responds to many forcings (GHGs, aerosols, volcanoes, solar, etc), but there are also internal variations. -rasmus]

    What, precisely, are these internal variations and what is their approximate magnitude and sign compared to forcings typically used in GCMs? I mean “precisely”, not a wave of the arm. 35 years in geology helps understand. What really caused the surface temperature drop, say 1940-70? You skirt all around the answer but you don’t answer it. Precisely.

    [Response: Precisely? - should we ignore the uncertainties in the forcing history, the difference in the transient behaviour in the real world and any one model simulation? Precision is all well and good, but I prefer accuracy. The accurate statement is that some part of the 1940's to 1970's change was likely driven by aerosols, and some part was due to the internal variability - possibly related to ocean circulation changes in the Atlantic making the 1940s anomalously warm. All of these proportions can be estimated, but the error bars are large. Thus no 'precise' attribution is ever likely to be credible. Unfortunate, but that's just how it is. - gavin]

    Next, at 33, Rasmus notes in response to funding for authors and possibilities of undue influence – [Response: To, blogs (like RC) may play an important role, as papers get discussed. Poor papers will be torn apart, and when authors know that they risk their paper being scrutinized and criticized, they will hopefully take more care to check their analysis. -rasmus] Question. From where does the financial backing for Real Climate weblog come? [edit]

    [Response: RC is a volunteer effort. No one gets paid for anything. Our annual expense are $30 for the domain name registration. - gavin]

    Comment by Geoff Sherrington — 28 Nov 2007 @ 4:55 AM

  47. Aren’t you curious why not? – gavin

    What I love about RC :-)

    Comment by Martin Vermeer — 28 Nov 2007 @ 7:45 AM

  48. Someone earlier enquired about the differences in the Solar TSI reconstructions, and especially the PMOD/ACRIM ones. I think this issue has been treated unfairly in this RC article, and I think it is due to a lack of understanding on the ACRIM project. The actual ACRIM website goes into detail about both these reconstructions, and why they believe the ACRIM one is probably more accurate.
    http://www.acrim.com/

    In Summary, what I feel is not being represented here is that BOTH the ACRIM and PMOD reconstructions use the ACRIM dataset from both ACRIM I and ACRIM II – You need to understand this. The problem lies in the ‘ACRIM GAP’ This was a two year period in which the ACRIM II satellite was delayed due to the Shuttle Challenger Disaster. To fill this two year gap ONLY the PMOD and ACRIM used other data to fill the gap years.

    Full details of this are on the ACRIM website. Also F&L used one of these reconstructions in their paper earlier in the year, and yet the validity of them using a ‘patched up’ TSI series was not even challenged by RC – so why drag this up for this paper?

    Simply speaking there are still major sensor problems in current TSI measurements. SORCE/TIM and ACRIM 3/ACRIMSAT both give differences in TSI readings in the order of almost 5 w/m2 ! It is still not understood why this is, as stated on the website, and hence modern measurements of TSI are anomalous to say the least -when the two current modern satellites give readings that are so apart.

    People on here seriously need to read and understand the information on http://www.acrim.com/ before making some of these misguided comments.

    Comment by Pete — 28 Nov 2007 @ 8:01 AM

  49. #45 Timo Hämeranta,

    The link you posted doesn’t work for me, but the paper is available from Wunsch’s page http://puddle.mit.edu/~cwunsch/ Link entitled “C. Wunsch, 2007. The Past and Future Ocean Circulation from a Contemporary Perspective, in AGU Monograph, 173, A. Schmittner, J. Chiang and S. Hemming, Eds., 53-74, (pdf) ” Wunsch’s publications page is great food-for-thought, I particularly enjoyed his papers on Ice Age changes and the Milankovitch cycles. But I’ve not read that one – yet.

    I pondered the ocean while still sceptical, once I’d satisfied myself that there was no evidence for a solar role in the recent warming (0.6degC in the last 30 years). This is very roughly why I ditched the oceanic line of thought:

    If the ocean were the source of the warming:
    1) Why is the warming concentrated over land in the Northern Hemisphere? http://data.giss.nasa.gov/gistemp/graphs/
    2) Why does there seem to be a correlation between warming rate and changes of “global dimming” (Wild) indicating a radiative source for the warming.
    3) Why the diurnal range changes and vertical profile of changes? Surely the ocean causing the warming (at the base of atmosphere) would cause a warming in all parts of the atmosphere.
    There may be other points – this is a rushed lunchtime post. I don’t see from the abstract you quote how that work supports an oceanic cause for the recent warming. The atmosphere may well be chaotic etc – however we still see the hadley cells shift in a reliable enough manner for cultures to have prospered for centuries with monsoonal rain patterns. i.e. chaotic does not mean devoid of predictable patterns.

    You are right in that there’s a lot of uncertainty, but I disagree that such uncertainty means we can attribute the observed warming to the ocean, or vulcanism, sensible industrial heat emissions, Piratic upwelling reductions etc etc etc

    As far as I can see, the best bet for explaining the last 30 years remains CO2. My attitude – go with the best working theory until/unless you have enough evidence to go with an alternate.

    PS “rely the studies you like, and don’t rely the studies you don’t like, you are no scientists.” In view of S&W’s lack of argument for choosing ACRIM over PMOD I wonder to whom you should be addressing that statement. In my experience it’s the denialist camp that engages most in cherry picking.

    That reminds me: I must check to see if you have enlightened us as to the rationale for your raising arctic oceanic circulation during what I recall was a discussion about the (atmospheric) AO.

    Comment by Cobblyworlds — 28 Nov 2007 @ 8:12 AM

  50. Timo, re: 45,
    My beef with your approach is that you are emphasizing uncertainties without considering their relative magnitudes or without considering the likely importance of the effects of those uncertainties. OK, let us say the oceans do wind up being more important (there’s no evidence supporting this, but assume it anyway). Does that mean that we will reduce CO2 sensitivity? No, because it is constrained by many independent lines of evidence. Rather, the give would have to come from some other less certain piece of the puzzle. Bottom line, only the feedbacks would likely change, and the feedbacks are more likely to result in an increase than a decrease (since that’s how they are distributed).
    Being a scientist means learning to deal with uncertainties and make predictions that take them into account. It does not mean throwing up you hands when confronted with a complex system and saying that it is beyond all human understanding.
    CO2 is emphasized because you simply cannot explain what is going on without it. That does not mean that other factors are being ignored.

    Comment by Ray Ladbury — 28 Nov 2007 @ 8:56 AM

  51. Re 20, 24, 29, 34

    Re 20 (Robert):
    E.g.
    Ammann C.M., F. Joos, D.S. Schimel, B.L. Otto-Bliesner, R.A. Tomas, 2007: Solar influence on climate during the past millenium: Results from transient simulations with the NCAR Climate System Model. PNAS, 104, 3713-3718.

    Foukal P., C. Fröhlich, H. Spruit, T.M.L. Wigley, 2006: Variations in solar luminosity and their effekt on the Earth’s climate. Nature, 443, 161-166.

    Bard E., M. Frank, 2006: Climate change and solar variability: What’s new under the sun? Earth and Planet. Sc. Lett., 248, 1-14.

    Gray L.J., J.D. Haigh, R.G. Harrison, 2005: A review of the Influence of Solar Changes on the Earth’s Climate. Hadley Centre technical note 62.

    Shindell D.T., G.A. Schmidt, R.L. Miller, and M.E. Mann 2003: Volcanic and solar forcing of climate change during the preindustrial era. J. Climate, 16, 4094-4107, doi:10.1175/1520-0442(2003)016.

    Solanki S.K. and N.A. Krivova, 2003: Can solar variability explain global warming since 1970? J. Geophys. Res., 108, 1200.

    Re 24 (Charles):
    If you want to explain the temperature rise after 1970 by the solar activity increase in the first half of the century, you need a time lag reaction of about 50 years (or more). SW do not mention that, they are just talking about lagged reaction (large relaxation time), but do not consider, what that would mean and if there is any hint in the data that would point to a corresponding relaxation. However, at the end they are talking about a time lag of 6 to 12 years which would exclude a current influence of the solar activity rise before 1950.

    Re 29 (Henning):
    From SW: Our calculations also assume that the observed secular preindustrial warming before 1900 is induced by the contemporary solar activity increase.

    Re 34 (Robert):
    The problem with SW is, that they try to get a possible percentage of solar influence as high as possible, regardless of the likelyhood of their assumptions. You are right to point out that per se the search for an upper limit is all right. However, some of their assumptions are very unlikely or questionnable. They assume e.g. that before 1900 the whole temperature trend is due to TSI increase and that the whole variability of global temperature on the interannual (about 10y) time scale is due to the 11y solar cycle (these are the two constraints they build their model on), and that 1 Wm-2 equals 1 K (very interesting…).
    Besides, their difference (citing themselves) comparing sun cycle 21-22 to 22-23 of ACRIM (0.45Wm-2) is also the highest one can find, since their cycle 21-22 does not begin at the maximum of 21 but ends at maximum of 22. My estimation for the cycles encompassing the maxima (1979- 1991, 1992 – 2000; the definition of the time of maximum is somewhat arbitrary, dependent on averaging) gives a difference of only about 0.25 Wm-2 for ACRIM, which is half of the SW value. For the averages of cycle 22 and 23 (1987- 1996.5, 1996.5 – 2007.3) I get a difference of about 0.04 Wm-2.

    Comment by Urs Neu — 28 Nov 2007 @ 9:52 AM

  52. Re 48 & 49,

    I do know all you say, I have discussed with the authors many times and filed all the relevant studies, over 6000 now. Besides uncertainties I’m always looking for alternative explanations to everything, and first after critical scrutiny we’ll see (or not) where the beef may lure.

    Well, when I take the big picture, in last three decades I see three major incidences

    - the 1977/78 global shift,
    - the 1998 super-el Nino, and
    - the enormous burst of warm water to Arctic Ocean observed from 2004 on

    About the latest one please see

    Polyakov, Igor V., et al., 2005. One more step toward a warmer Arctic. Geophys. Res. Lett., 32, L17605, doi:10.1029/2005GL023740, September 9, 2005

    Extract from the Abstract

    “This study was motivated by a strong warming signal seen in mooring-based and oceanographic survey data collected in 2004 in the Eurasian Basin of the Arctic Ocean. The source of this and earlier Arctic Ocean changes lies in interactions between polar and sub-polar basins. Evidence suggests such changes are abrupt, or pulse-like, taking the form of propagating anomalies that can be traced to higher-latitudes. …”

    AGU Highlights:

    “Arctic Ocean waters warm suddenly

    New research on water flowing from the North Atlantic Ocean into the Arctic provides evidence that the Arctic Ocean is warming. Polyakov et al. measured the temperature, salinity, and velocity of the Atlantic Water, a warm, salty layer (150-900 meters [500-3,000 feet]) of ocean water that flows through the Norwegian Sea into the Arctic Ocean. The temperature of the Atlantic Water entering the Arctic Ocean increased dramatically in 2004, warming in two abrupt stages in February and August. The anomalously warm water is currently flowing along the basin margins toward the interior of the Arctic Ocean. The authors suggest that enhanced westerly winds in the North Atlantic pushed warm water into the Norwegian Sea, and from there it flowed into the Arctic Ocean. These winds are due to changes in atmospheric conditions, but the authors say more evidence is needed to determine if the associated warming is the result of long-term change or part of a recurrent climate cycle. The authors’ observations do indicate, however, that the Arctic Ocean is currently warming, a trend that could reduce Arctic ice cover and influence ocean processes in more southerly regions.”

    See also

    Sitnews June 12, 2005 at
    http://www.sitnews.us/0605news/061205/061205_ak_science.html

    Extract:

    “…A rise in water temperature from 0.4 to 0.8 degrees Celsius (32.7 to 33.4 degrees Fahrenheit) is a big change in the stable environment of the Arctic Ocean, said Dmitrenko’s colleague, Igor Polyakov, who also works at the International Arctic Research Center in Fairbanks.
    “It’s as if the planet became warmer in a single day,” Polyakov said.
    Interested in the pulse of warm water, Polyakov contacted oceanographers from around the world to backtrack the water on its path to the high Arctic. Norwegian scientists have moored stations in the Norwegian Sea, and German scientists monitor stations in Fram Strait, between Greenland and Svalbard. Using information from those stations and others, Polyakov and his coworkers found that the warm water passed Norway in 1998 and took about six years to reach the mooring station north of the Laptev Sea. That warmer water now resides in the Arctic Ocean, where it will remain for years caught up in currents that swirl counterclockwise in several giant basins north of the world’s landmasses…”

    ….

    Well, besides these three huge incidences originating from the oceans other climatic events and trends are quite trivial. Speaking of climate I always exclude weather events.

    Finally, when we return back to the main issue of this discussion, the Sun, please see the new study

    Usoskin, Ilya G., Sami K. Solanki, and G.A. Kovaltsov, 2007. Grand minima and maxima of solar activity: new observational constraints. Astronomy & Astrophysics Vol. 471, No 1, pp. 303-307, August III 2007, online http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf

    Comment by Timo Hämeranta — 28 Nov 2007 @ 10:11 AM

  53. Re: #46 (Pete)

    Regarding PMOD vs ACRIM, the information on the ACRIM website is only one side of the story. Interested readers should also study this paper by Frohlich, and I’ve posted on that topic myself.

    Comment by tamino — 28 Nov 2007 @ 10:19 AM

  54. Re Gavin: “RC is a volunteer effort. No one gets paid for anything. Our annual expense are $30 for the domain name registration.”

    Just the kind of full financial disclosure I’d like to see from other sources of putatively scientific information! To cut to the chase: the single property shared by the “science” of almost all the stuff RealClimate takes pains to debunk is corruption – plain and simple. I don’t mean to sound moralistic in this assertion, but only to point out an obvious thing

    [edit - please don't make unsubstantiated specific allegations]

    Comment by Daniel C. Goodwin — 28 Nov 2007 @ 10:52 AM

  55. Thank you for your conscientious edit (really).

    It’s a challenging concept to frame dispassionately, which is my goal here – obviously, you’ll hold this one back if you find it inappropriate, and I can appreciate that. One more try…

    A phenomenon which might be called “scientific fraud” is a feature, in my view, not only of several shoddy papers I’ve seen of late, but also an attribute which attaches to the authors and publishers of those papers (particularly in cases where the same cast of characters keeps coming up with the same tired old nonsense – I don’t mean to include honest mistakes in this category). It seems like a fairly bland assertion to me, and yet it is tricky to posit in a manner which doesn’t upset the lawyers.

    This phenomenon has a rich and storied history as long as that of science itself – so in a way my suggestion is that historical precedents for “scientific fraud” are ripe for the plucking, in case they inform your discussion.

    [Response: Shoddy is not necessarily fraud. Ignorant is not fraud. Deliberate obfuscation or repeating tired old nonsense is not fraud either (though it doesn't do much for ones scientific credibility). Faking data, doctoring photographs or samples is fraud though. In the cases we have been discussing the problems don't add up to anything approaching that and the accusations that they do, don't lead to very much except to ever more expansive rhetoric. Sticking to the issues and assuming good faith (unless it is clearly not warranted) is more fruitful in the end. - gavin]

    Comment by Daniel C. Goodwin — 28 Nov 2007 @ 11:31 AM

  56. Re: #53 (tamino)

    I do appreciate this Tamino, and I have previously read your thread in which Dr Willson himself appeared :)

    I just wanted to highlight that PMOD(composite) is still stitched together from 7 segments from 1980: ERB>ACRIM1>ERB>ACRIM1>ERB>ACRIM2>VIRGO then reconciled to the VIRGO scale and then fitted into a previous proxy reconstruction pre 1979.

    Whereas ACRIM(composite) is stitched together from 1980: ERB>ACRIM1>ERB>ACRIM2>ACRIM3.

    I just think both methods are unsatisfactory really, but it’s the best we have from real data. The current ACRIM 3 / SORCE differneces just show the uncertainties currently existing in this field.

    Any paper using either of these, in my view, is well advised to model results and conclusions on both these composites, as has happened with S&W. Whereas the Royal Society F&L paper earlier this year chose to ignore the ACRIM composite completely. Who’s the more incorrect in this situation? With S&W you have a choice it seems to me!

    Comment by Pete — 28 Nov 2007 @ 11:32 AM

  57. In 52, Tim makes the extraordinary claim that “besides these three huge incidences originating from the oceans other climatic events and trends are quite trivial.”

    Tell it to Perth and Sydney.

    Comment by Jim Galasyn — 28 Nov 2007 @ 11:41 AM

  58. Re #45 Cobblyworlds:

    The problem I saw was not with fig 6b vs 5b, but in the last decade of 6b where the two modeled temperatures deviate by 0.1 degrees despite the two TSI curves being the same for the last six decades. But also why is there almost no difference between the two modelled temperature curves both in fig 5 and 6 pre-1950 where the two TSI curves deviate by up to 1.5 W/m2? The only sensible conclusion seems to me that these deviations demonstrate how non-physical the results are.

    Comment by Erik Hammerstad — 28 Nov 2007 @ 11:41 AM

  59. Timo,
    Thanks for Usoskin’s latest contribution. After a quick perusal, it looks interesting–particularly the lack of periodicity seen. A couple of comments and questions. The statistics are really not good enough to make detailed conclusions about distributions. In particular, it is not clear to me that the distribution of Minima distributions would necessarily be bimodal. It could be simply long-tailed, with the clustering in the second “mode” being due to statistical fluctuations. This is particularly true, since these long-duration events are infrequent, and the reconstructions may have more uncertainty the further back one goes. I don’t see any obvious implications for current climate studies of models.

    Comment by Ray Ladbury — 28 Nov 2007 @ 12:10 PM

  60. #9, Urs, “This is funny, since one of the beloved sceptic arguments is that the CO2 increase during ice age cycles lag the temperature increase by more than 600 years. So we will still have to wait a few hundred years to see the CO2 increase due to the temperature increase since the Maunder Minimum (apart from evidence by the isotopic footprint).”

    We don’t have to wait 600 years, all we have to do, is go back 600 years, use a proper proxy and look for a 1407 spike in CO2… Thank goodneess for contrarians pointing out the right direction. Now they will have irrefutable proof that they are full of ideas devoid of verification.

    Comment by wayne Davidson — 28 Nov 2007 @ 1:14 PM

  61. When Tamino (#52) refers to Klaus Frölich’s new paper (and Gavin Schmidt has used the same reference), it’s proper to refer to the following new paper, too, and to the comments it has invoked:

    Lockwood, Mike, and Claus Fröhlich, 2007. Recent oppositely directed trends in solar climate forcings and the global mean surface temperature. Proc. Royal Soc. A, in press, July 2007, online http://www.pubs.royalsoc.ac.uk/media/proceedings_a/rspa20071880.pdf

    Abstract

    There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.

    5. Conclusions

    There are many interesting palaeoclimate studies that suggest that solar variability had an influence on pre-industrial climate. There are also some detection–attribution studies using global climate models that suggest there was a detectable influence of solar variability in the first half of the twentieth century and that the solar radiative forcing variations were amplified by some mechanism that is, as yet, unknown. However, these findings are not relevant to any debates about modern climate change. Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability,
    whichever of the mechanisms is invoked and no matter how much the solar variation is amplified.

    ….

    Well, very, very determined position.

    Yet, please see e.g.

    Reference Frame / Lubos Motl July 22, 2007

    “Nir Shaviv: Why is Lockwood and Fröhlich meaningless?

    One of the newest articles at RealClimate.org contains a link to the full text of a recent article by Lockwood and Fröhlich who argue that “all” potential aspects of the Sun in the last 20 years that could be responsible for warming in that period went the wrong way. Well, there are many questions: for example, was there a warming that one should talk about? There wasn’t one in the last ten years.

    A more important question is whether their whole article is correct…..”

    Please see also

    Reply to Lockwood and Fröhlich –
    The persistent role of the Sun in climate forcing

    Svensmark, H. and Friis-Christensen, E.

    Danish National Space Center
    Scientific Report 3/October 2007

    online http://www.spacecenter.dk/publications/scientific-report-series/Scient_No._3.pdf/view

    …..

    Well, my only comment is that experts disagree.

    As far as I can see, also in the foreseeable future.

    [Response: Ahh... experts disagree (about what we are not told), therefore we know nothing. Perfect! Actually they don't. Even S+FC's latest (unpublished) piece accepts that the trend in temperature cannot be explained by the CR data (since they remove the trend from their analysis). Thus, we actually find an agreement! Maybe we do know something? - gavin]

    Comment by Timo Hämeranta — 28 Nov 2007 @ 1:25 PM

  62. Re #59 Ray:

    I ask Ilya Usoskin. My dear friend Ilya usually is willing to communicate, if not too busy.

    Comment by Timo Hämeranta — 28 Nov 2007 @ 1:29 PM

  63. Errata, its easier, we rather need to look for a 1407 spike in temperature, or any other recent 600 year temperature to CO2 correlation, lets say something known like 400 to 1000 AD correlation etc.. .

    Comment by wayne Davidson — 28 Nov 2007 @ 1:53 PM

  64. Re Gavin: on fraud (#55)

    I’ve very much taken your response to heart. I think you are right about what is productive and non-productive discussion, an insight so key to making RealClimate pertinent. I learn even more than I expect to here. Thanks.

    Comment by Daniel C. Goodwin — 28 Nov 2007 @ 1:54 PM

  65. Re # 61 Gavin’s comment:

    Link to Nir Shavis’s analysis (above) is

    http://motls.blogspot.com/2007/07/nir-shaviv-why-is-lockwood-and-frohlich.html

    I further copy a bit as follows:

    “…L & F state that from 1985, there is a discrepancy between solar activity, which decreased, and the global temperature, which increased. Hence, solar activity cannot explain the observed warming. This conclusion, however, is flawed for several reasons….

    So why has the temperature continued increasing even though the solar activity diminished? This has to do with the second point, which is very important, but totally ignored by L & F.

    L & F assume (like many others before) that there should be a one-to-one correspondence between the temperature variations and solar activity. However, there are two important effects which should be considered and which arise because of the climate’s heat capacity (predominantly the oceans). First, the response to short term variations in the radiative forcings are damped. This explains why the temperature variations in sync with the 11-year solar cycle are small (but they are present at the level which one expects from the observed cloud cover variations… about 0.1°C). Second, there is a lag between the response and the forcing. Typically, one expects lags which depend on the time scale of the variations. The 11-year solar cycle gives rise to a 2 year lag in the 0.1°C observed temperature variations. Similarly, the response to the 20th century warming should be delayed by typically a decade. Climatologists know this very well (the IPCC report, for example, include simulation results for the many decades long response to a “step function” in the forcing, and climatologists talk about “global warming commitment” that even if the CO2 would stabilize, or even decrease, we should expect to see the “committed warming”, e.g., Science 307), but L & F are not climatologists, they are solar physicists, so they may not have grasped this point to the extent that they should have….”

    Hopefully the link above opens to everyone interested to read the full text.

    [Response: Ahh.... so the acceleration of the warming in the last 30 years is because of the solar forcing increases in the 1940s? And this is the expected outcome from a simple model with an ocean heat capacity? Hmm... maybe you could point us to a simple model that shows this behaviour if it is so obvious? All of the ones I have seen respond to a step with an exponentially decreasing warming, not an ever increasing one. But not even S+FC make this argument! They state clearly that:

    "After the removal of confusions due to ... a linear trend ... the negative correlation between cosmic-ray flux and tropospheric air temperatures is impressive."

    Thus they are no longer claiming the trend is due to GCR. Why do you insist that it is? - gavin]

    [Response: To re-iterate one of the points made here in this thread: It's a fact that the global mean temperature leveled out after 1940 and even decreased a little until 1970. A delayed response from a solar forcing - if it were important - would on the other hand suggest strongest warming in this period. So you need to answer: 'Can a response to a forcing wait and then bounce up after a period of inertness?'. The alternative explanation is that there are other factors which are more important than solar forcing. One such candidate is aerosols, but the pronounced warming since 1970 is still difficult to explain in terms of solar forcing. However, if the climate sensitivity is high for these factors, why should it be any less for increased GHG? After all, AGW surely involves many of the similar feed-back processes e.g. involving changes in vapour, snow/ice albedo, lapse-rate, and clouds. -rasmus]

    Comment by Timo Hämeranta — 28 Nov 2007 @ 2:54 PM

  66. Timo (#61): You claim that “experts disagree” and yet the “expert” you cite states “there wasn’t [a warming] in the last ten years”. That, in my opinion, means that your “expert” is only an expert in obfuscation, and not in real climate science. Look at either the GISS or HadCrut temperature records: do a multiple year smoothing (try 5 years for example) and you’ll see a clear continuing warming signal.

    Meanwhile, Svensmark et al. (these were the same folks that in the early 90s attempted to attribute recent warming to solar trends, only to have it pointed out that their 30 year averaging algorithm meant they couldn’t actually talk about anything post 1960 or so, right?) detrend their signal by 0.14 K/decade to get a match to a cherry-picked tropospheric data set (claiming that some mysterious natural greenhouse feedback is as likely as anthropogenic GHGs to account for it), and claim that their ocean and troposphere data sets are more reliable than surface temperature records? And also claim that figure 1e is “roughly flat” since 1998, when even the roughest attempt at statistical analysis beyond eyeballing it shows that it isn’t at all flat.

    All in all – I find your “experts” quite lacking.

    Comment by Marcus — 28 Nov 2007 @ 3:31 PM

  67. Gavin, you suggested climate science is in its adolescency. Where is your current focus? What else could be discovered that we don’t already know? Is your main job from here on out media relations? Why not just turn off your Blueice and go home?

    [Response: There's tons to do: Getting a grip on D/O events, understanding the last deglaciation, understanding the variability in 'interglacial times', aerosol impacts, improving the models, ice sheet dynamics, cloud resolving etc. No need to go home just yet. But if all you want to know about is the impact of greenhouse gases, you already know enough to act. - gavin]

    Comment by Michael — 28 Nov 2007 @ 3:41 PM

  68. Svalgaard is presenting at the 8:00 AM Wednesday session (GC31B), presided over in part by Scafetta and Willson. As Erik noted, Svalgaard is talking about minima being the same, but I believe he’s referring to minima of the 22-year cycles, which would imply that the maximas can’t have much variation either, leading to the conclusion that there isn’t a century-scale solar forcing (as opposed to a decadal one, which would refer to the 22-year cycle).

    TI: (No?) Century-scale Secular Variation in HMF, EUV, or TSI
    AU: * Svalgaard, L
    EM: leif@leif.org
    AF: ETK, Inc., 6927 Lawler Ridge, Houston, TX 77055-7010, United States
    AB: Recent work suggests that the Heliospheric Magnetic Field (HMF) strength, B, at each sunspot minimum varies but little (less than a nT). The variation of B within a solar cycle seems to be due to extra (and likely closed) magnetic flux added by Coronal Mass Ejections (CMEs) riding on top of a “floor” of somewhere between 4 and 5 nT, leading to the conclusion that the open magnetic flux is nearly constant with time, and that, in particular, there is no secular variation of the open flux. B inferred from geomagnetic data back to the 1840s further support this conclusion. In fact, B for the current cycle 23 matches well B for cycle 13, 107 years earlier. The amplitude rY of the diurnal variation of the geomagnetic Y-component is an excellent proxy for the F10.7 radio flux and thus also for the EUV flux (more precisely, the FUV, as the Sq current flows in the E layer). As for the HMF there seems to be a “floor” in rY and hence in F10.7 and hence in the FUV flux, thus the geomagnetic evidence is that there has been no secular change in the background solar minimum EUV (FUV) flux in the past 165 years. Direct measurements (although beset by calibration problems) of the Total Solar Irradiance (TSI) from satellites have only been available for 30 years and indicate that solar irradiance increases with solar activity. Correlating mean annual TSI and sunspot numbers allows one to estimate the part of TSI that varies with the sunspot number. If TSI only depends linearly on the sunspot number then irradiance levels during the Maunder Minimum would be similar to the levels of current solar minima. But TSI is a delicate balance between sunspot darkening and facular brightening, and although both of these increase (in opposite directions) with increasing solar activity, it is not a given that there could not be secular variations in the relative importance of these competing effects. Reconstructions of TSI, all postulate a source of long-term irradiance variability on centennial time scales. Each group of researchers have their own preferred additional source of changes of the “background” TSI, such as evidence from geomagnetic activity, open magnetic flux, ephemeral region occurrence, umbral/penumbral ratios, and the like. The existence of “floors” in HMF and FUV over ~1.6 centuries argues for a lack of secular variations of these parameters on that time scale. I would suggest that the lack of such secular variation undermines the circumstantial evidence for a “hidden” source of irradiance variability and that there therefore also might be a floor in TSI, such that TSI during Grand Minima would simply be that observed at current solar minima. This obviously has implications for solar forcing of terrestrial climate.

    Comment by Steve Bloom — 28 Nov 2007 @ 3:58 PM

  69. Regarding Nick #13 and later responses.

    I have to agree with Nick”s response, at least that was the thought I had when reading the article. In other words if S&W claim solar is the only forcing worth considering and feel the cooling is due to delay only and not Aerols etc., Rasmus could be more clear. I am glad Nick asked this question better than I could and for Gavin’s reply.

    I have to admit the discussion though is a bit too technical for me to follow. But I will take a few more passes at it.

    Comment by Larry — 28 Nov 2007 @ 4:03 PM

  70. #58 Erik Hammerstad

    Sorry about that, I misread.

    They use different values of relaxation time reponse(Tau), and insolation scaling factor(alpha). I think the main factor in creating the effect you describe would be the value of Tau. Fig 6a and both of 5 show lesser deviations

    As they’ve derived the values of Tau and Alpha from the whole of each respective Lean/Wang Dataset I’d expect the parameters to differ and S&W’s defence to what you say could be that the difference is down to the difference between Lean & Wang.

    That one aspect doesn’t bother me about the paper. Its unphysical because it’s trying to get agreement between one variable, in a multivariable context. I accept that they could be argued to show the (surely accepted) pre-1950 dominance of solar forcings on a multi-decadal scale. Note that their graph has significant enough deviations from observations for the “wiggle room” needed for other “natural” factors.

    Indeed whilst I certainly wouldn’t rely upon this paper it seems to me to generally suggest Mann03 rather than Moberg05 is closer to reality. That’s because the latter 20th Century deviation suggests the sort of room CO2 increases take up in attribution studies. With the same sort of deviation from modelled results in the 1950s (must find out if it’s known what that was due to). e.g. http://www.globalwarmingart.com/wiki/Image:Climate_Change_Attribution_png Note – I am comparing northern hemisphere vs global here- so it’s rough.

    If I had to bet on what I think is the most “true” of the four graphs I’d bet fig5a – but that’d be a hunch nothing more. On balance though, I’m just not keen on “phenomenological approaches”, even when they support the theory of AGW (there was a statistical attribution study that did a while back – but I forget the names now).

    *******************************************************

    I’ve got some sympathy with Robert A Rohde, but given S&W’s track record and notably paragraph 7. Which seems to me can only be placed there to confuse those who don’t know of the multiple strands of evidence that support the conclusion that the rise in CO2 is due (substantially) to fosil fuel burning.

    Is the paper about TSI/GAT attribution or about CO2? What they’re doing there is superfluous to their scientific purpose, as far as I can see it’s inclusion demonstrates their real purpose – to hoodwink those unfamiliar with the wider body of evidence.

    Comment by CobblyWorlds — 28 Nov 2007 @ 4:04 PM

  71. Svalgaard explains that S+W 2007 is based on bad data:

    “Scafetta & West 2007 uses and compares the TSI [Total Solar Irradiance] reconstructions by Lean 2000 and Wang et al. 2005. Lean’s is pretty much ruled out as the secular increase since the M.M. [Maunder Minimum] is much too large. Wang’s has no secular change [check the minima values] up to 1900, but then takes off during the 20th century, largely based on the Lockwood open flux doubling. Since not even Lockwood believes the doubling any longer, there is no reason for Wang and us to believe in it either, and the large increase [S&W, Figure 3] in TSI during the 20th century is simply not there. Therefore the solar influence is also not there. So, now we have two things to explain:
    1) the warming during 20th century, and
    2) the cooling during the LIA
    None of which are caused by the sun.
    So, we invoke Natural [other than solar! other than solar! other than solar! other than solar!] Causes [NC] for the cooling and Human causes [HC] for the warming. Doesn’t sound right to me.”

    On those latter points, IIRC there are perfectly good reasons why the anthropogenic causes would net out to warming, and the LIA could only be a problem if it is a) assumed to be a substantial global phenomenon (a point which is at least in some dispute) and b) not largely explainable by a combination of natural variability and volcanic activity. But is there any validity to the supposition (which Svalgaard admitted was based on very little direct knowledge of the models) that knocking out the solar trend from the first half of the twentieth century would throw the models for a loop? I said I didn’t think so, but there I’m on very shaky ground. Gavin?

    Comment by Steve Bloom — 28 Nov 2007 @ 4:34 PM

  72. #52 Timo Hämeranta

    No problem with asking the awkward questions, when it’s done to provoke fruitful re-examination of things which are tacitly accepted.

    - the 1977/78 global shift,
    - the 1998 super-el Nino, and
    - the enormous burst of warm water to Arctic Ocean observed from 2004 on
    also
    - 1990s shift in modal tendency of the Arctic Oscillation.
    - what looks like an upward trend in NATL cyclone activity.
    etc

    All happening at the same time as increasing CO2 levels (a gas expected to cause warming on a global average basis) and a “coincidental” global warming. A warming that, if not forced by internal variability, does affect the sort of climatic phenomenae we expect. e.g. Coral research suggesting a predominant EN state in warmer periods.

    By the way.
    Check out the graph of seasonal area(extent?) at Cryosphere Today: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg
    It’s apparent that there’s been a summer warming trend long before 2004 (some small factor being “amiplified” by ice-albedo feedback?). And the flushing out of perrenial ice due to the +ve AO mode happened in the 1990s. With the reduction of the damping factor that is perrenial ice, natural changes are then able to have an impact they didn’t have before.

    Comment by CobblyWorlds — 28 Nov 2007 @ 4:47 PM

  73. [Response: RC is a volunteer effort. No one gets paid for anything. Our annual expense are $30 for the domain name registration. - gavin]

    Wow.. really. Where can I get a free host and web server for my domain. Thats a sweet deal. Especially for the bandwidth that a site like this consumes. Inquiring minds want to know.

    [Response: Inquiring minds should simply try looking. This is what we said when we started. - gavin]

    Comment by cbone — 28 Nov 2007 @ 5:08 PM

  74. Help me out, I don’t grasp how “Getting a grip on D/O events, understanding the last deglaciation, understanding the variability in ‘interglacial times’, aerosol impacts, improving the models, ice sheet dynamics, cloud resolving etc.” won’t impact my understanding of the role of greenhouse gases, and what I should do about them.

    We are somewhere in the middle of an ‘interglacial time’, are we not?

    [Response: Sure, but this is the only one CO2 has reached 380 ppm and is still climbing. We are not going to learn from past interglacials what that does (since it hasn't happened before), but we may learn something about the stability of the ice sheets, ecosystem and ocean circulation dynamics in those regimes. It all might feed into improved model evaluation, and conceivably improve predictability into the future. These factors are the most uncertain going forward, but there's tons of stuff that is pretty certain that no amount of D/O-related research is going to shift. Bottom line, tons of science to do, probably minimal change in what policy-makers will hear. - gavin]

    Comment by Michael — 28 Nov 2007 @ 6:28 PM

  75. [Response: Inquiring minds should simply try looking. This is what we said when we started. - gavin]

    So, you are ‘hosted’ by a sock puppet for an environmental PR firm that also represents groups like Greenpeace and other environmental firms who do have a vested financial interest in promoting AGW. Based on the standard that skeptics are held to here, with regards to similar ties to industry they are immediately dismissed without comment on the merits of their arguments. Why should your commentary not merit similar treatment (Just because they don’t pay you doesn’t mean that your access to this venue is not of some value to you.) Again, based on the standards for credibility that you have repeatedly endorsed (usually) indirectly by allowing them to pass unchallenged, you too represent a biased viewpoint and your credibility too is questionable.

    [Response: Credibility is a funny thing. I generally reserve it for people who have been conscientious about they do, have a track record of not dissembling or passing disinformation, who do not misrepresent what others say and who argue honestly. I have never argued that industry money ipso facto removes credibility - people like Michaels lose credibility due to their actions, not their (anonymous) funders. But if you think we're cheap enough to be bought off with a free server account, try buying us lunch - who knows what we'll do for that? - gavin]

    Comment by cbone — 28 Nov 2007 @ 6:31 PM

  76. cbone, congratulations. That may well be the most pathetic post I’ve ever seen here on RC. Golly, someone is concerned about climate change and so they host a group of climate scientists who answer questions (FOR FREE) for blockheads like you. Oh my, what if they take away the server account? Then Gavin et al. might only be half as overworked as he is and that would be tragic for him, wouldn’t it?
    Your swiftboating technique is rather reminiscent of James Inhofe’s denunciation of Dr. Jim Hansen for “taking money from a liberal think tank”. Of course you do a little digging and find that Hansen won a prize from the Heinz Family Foundation for his climate work–in 2001, long before John Kerry even thought about running for president. Karl Rove, is that you?

    [Response: I start to think that such a think - sulking because the number of rational arguments has dried up - is to be expected. But, please, judge us on what we write, the arguments that we present, the empirical/modelling evidence we use, and the logic that we follow. -rasmus]

    Comment by Ray Ladbury — 28 Nov 2007 @ 9:32 PM

  77. Re # 75 cbone: “…you too represent a biased viewpoint and your credibility too is questionable.”

    To support your allegation of bias by the RC moderators, you need to provide evidence that Environmental Media Services somehow influences the research they (RC moderators) conduct or the papers they publish, or somehow exerts editorial influence over the content of RealClimate threads – if you have evidence of such influence, please share it. Inquiring minds would love to know.

    Comment by Chuck Booth — 28 Nov 2007 @ 10:50 PM

  78. There are a number of papers that predict the sun is moving to a Maunder minimum. (Solar minimums have been shown to occur every 200 years and the Dalton minimum was 200 years ago.) We should have an opportunity to determine how much of the 20th century warming was attributable to solar as compared GWG, if the solar minimum occurs starting cycle 24.

    Any thoughts concerning what to expect?

    The following is an explanation of the mechanisms which the sun is hypothesized to modulate planetary clouds.

    Solar mechanisms – Electroscavenging

    The 20th century solar contribution to global warming is hypothesized to be due to the process called “electroscavenging” which reduces planetary cloud independently of GCR flux.

    Electroscavenging is caused by electrostatic charge which is created by high speed solar wind bursts. The high speed solar winds bursts were created by coronal holes that moved to the solar equator at the end of the solar cycles 21 and 22. The electroscavening processes removes clouds and masks the increase in GCR at the end of the solar cycle.

    The following is a paper that explains the different mechanisms by which solar activity can modulate clouds. See the figure 3.1 for a diagram that shows how electroscavenging removes cloud forming ions.

    “Atmospheric Ionization and Clouds as Links between Solar Activity and Climate” By Brian Tinsley and Fangqun Yu

    http://www.utdallas.edu/physics/pdf/Atmos_060302.pdf

    “Electroscavenging depends on the buildup of space charge at the tops and bottoms of clouds as the vertical current density (Jz) in the global electric circuit encounters the increased electrical resistivity of the clouds. Space charge is electrostatic charge density due to a difference between the concentrations of positive and negative ions.

    The magnitude of Jz depends not only on the GCR flux, but also on the fluxes of MeV electrons from the radiation belts, and the ionospheric potentials generated by the solar wind, that can vary independently of the GCR flux.”

    Comment by William Astley — 28 Nov 2007 @ 11:39 PM

  79. Ahhhm… regarding the reliability record of this website (technically) the host can – if anything – only be suspected to actually sabotage RC. ;-)

    Comment by henning — 29 Nov 2007 @ 2:20 AM

  80. Re # 65 to Gavin:

    You do know I only forwarded information for consideration, and personally haven’t argued anything about GCR.

    Re # 72 to ‘CobblyWorlds’:

    I know that ‘there’s been a summer warming trend long before 2004′, it’s also in the papers I have forwarded.

    But let’s concentrate in this discussion to the Sun.

    Comment by Timo Hämeranta — 29 Nov 2007 @ 2:37 AM

  81. This is completely off-topic, but it’s good news for a change, so I’d like to share it with you all:

    You may be aware that Australia recently had an election and that the government of John Howard (a good mate and supporter of George Bush) has been crushed by the left leaning Labor Party (led by Kevin Rudd with the support of the Australian Greens. Howard himself lost his seat to a very switched on former journalist from the Australian Broadcasting Commission – Maxine McKew.

    It is widely recognised that the backward stance of Howard with respect to climate change played a significant role in the change of government.

    Labor has announced that it will sign the Kyoto protocol and work with other nations to help ensure that the next one is effective. It’s notable that during the election, the national mining and energy labor union supported Labor and ran advertisements calling for action on climate change. The new leader of the outgoing ‘Liberal’ party has declared support for Labor’s stance on Kyoto (in Australia the ‘Liberal’ party are the right-wing conservatives). Given the amount of coal and steel we sell to China, the fact that Mr Rudd speaks fluent Mandarin makes for interesting possibilities during international dialog on the issue.

    Now to top it all of, Rudd has declared that his minister for the environment, heritage and the arts will be Mr Peter Garrett – the former head of the Australian Conservation Foundation (equivalent to Sierra club in the US and the RSPB in Britain). And in addition, Ms Penny Wong has been appointed as Minister for Climate Change and Water (yep it’s so important they have appointed a dedicated minister). The new Deputy Prime Minister Julia Gillard is the first woman ever to hold that role.

    Besides holding power nationally, the Labor party also holds power in every state and territory in the nation. These governments have been battling the national government for years to get meaningful greenhouse policies in place.

    It’s always easy to be cynical (‘no matter what, you always get a politician’). But this new crop includes some of the most committed, intelligent, environmentally savvy, socially progressive people in the country.

    To find the highest ranking right-wing politician in Australia you now have to look to the Mayor of Brisbane.

    It’s like some kind of miracle!

    Within a month or two, the US will be the only hold-out on Kyoto.

    Comment by Craig Allen — 29 Nov 2007 @ 2:50 AM

  82. Urs #51:

    Thanks for the references.

    I am a little surprised you included Solanki and Krivova though. That paper goes through basically the same curve fitting approach as S&W with basically the same result. In other words, by crudely fitting solar variability to temperature, they also get something like 50% of the 20th century warming “attributable” to solar variation, with a smaller fraction of the recent warming. (They state it as “we conclude that the Sun has contributed less than 30% of the global warming since 1970″, which is arguably more severe than the typical S&W result.)

    I don’t actually believe that 50% of the 20th century is solar, but I do think simple limits arising from data-driven models provide a useful counterpoint to the very complex and opaque climate models usually used (see, for example, Ammann et al. in Urs’s references). When it comes to communicating climate change to others, it is lot harder to convince people to believe a GCM they can’t possibly understand than to have them compare data on a screen.

    Comment by Robert A. Rohde — 29 Nov 2007 @ 3:41 AM

  83. Richard Rohde,
    Solanki et al. is constructed as a reductio ad absurdum–they admit that the assumptions they are making are unreasonable and then say, “See, even making these unreasonable assumptions, solar variability could only account for ~50% of the last century’s warming. S&W may be equally absurd, but they are seeking to justify those absurdities. As such, S&W deserve no more credit for a reductio ad absurdum argument than a tenor whose pants rip in “The Marriage of Figaro” deserves to be called a comic opera genius. The audience would be laughing as much if it had happened in “Madame Butterfly” or “Faust”.
    It is unfortunate that people get wrapped around the axle wrt models. They are tools to aid in physical understanding and intuition–nothing more. If people go in with that understanding, and if they understand that much of the model is constrained independently of the data under consideration, the inescapability of anthropogenic causation becomes manifest.

    Comment by Ray Ladbury — 29 Nov 2007 @ 9:00 AM

  84. #80 You missed the most important thing about the good Mr. Garrett–lead singer for Midnight Oil.

    (Incidentally, some of the Aussie papers seem to suggest that Garrett has been given half a ministry, with Wong getting the other half, because of gaffes made during the election campaign).

    Comment by bigcitylib — 29 Nov 2007 @ 9:14 AM

  85. William Astley, I notice your reference has yet to be published. How was it reviewed? I also see some significant problems–why did we not see rapid warming in the late 1800s, for instance. Solar forcing also has a lot of trouble reproducing qualitative features of the warmingMoreover, the fact of the matter is that CO2 sensitivity is fixed by several independent lines of evidence. Thus, if there is another significant contributor, it will likely affect our estimates of quantities we DON’T know (e.g. aerosols) rather than those we do (e.g. CO2). Thus, any decrease in solar forcing will buy at most a temporary reprieve (and probably a return to complacency) before the end of the Minimum brings the return of warming with a vengeance. That CO2 is responsible for most of the current warming is really inescapable. See:
    http://www.realclimate.org/index.php/archives/2007/11/global-dimming-and-global-warming/
    These data are inconsistent with a solar mechanism.

    Comment by Ray Ladbury — 29 Nov 2007 @ 9:22 AM

  86. From the paper at (3):

    “PTM assumes that the climate system, to the lowest order approximation, responds to an external radiative forcing as a simple thermodynamical system, which is characterized by a given relaxation time response t. This should be a valid approximation for small variation of the input forcing.”

    Why?

    Making the variation small does not necessary alter the dynamics of a system. I do understand that if the system is presumed to be non-linear it may be approximately linear for small forcings.

    However if the model is invalid (i.e.. does not have a single time constant) making the forcing small will not change matters.

    For instance if the system contains momentum it can contain resonances or more generally behave with different phase delays and amplitude responses at different frequencies. If it has resosances they will not go away just because you tap the bell lightly. It will still ring.

    The system does contain momentum and is capable of oscillations.

    If this was an ordinary investigation one might use solar variation as a probe to investigate the response of the system to a forcing with an eleven year period. As we cannot determining the attenuation of the response directly (climate sensitivity is not sufficiently well known) we only have the phase to work with. Plus if we are lucky and the forcing contains not just a fundamental frequency but also higher harmonics we can examine the relative amplitudes of the harmonics.

    From the paper:

    “We observe that both properties are expected for the climate system where it has been found that the climate sensitivity and the time lags to a forcing decrease with the frequency of the forcing because of the damping effect of the ocean and atmosphere thermal inertia”

    When analysing cyclic forcings it is the phase not the time lag that you need to investigate. Their simple model would predict that as the amplitude of the response decreases with increasing frequency the phase delay should approach pi/2 (90 degrees). Now phase is not mentioned in the paper and it is critical to the analysis.

    If the amplitude to long period forcings is 3 times that for the 11yr cycle then the 11 cycle should be delayed by about 0.4 pi or 70 degrees or 2.15 years (for the fundamental frequency or first harmonic) higher harmonics ought to be highly attenuated ( the third by the factor 9 the fifth by a factor of 15).

    As far as I am aware “Tung & Camp (2007)” (not quoted in this paper) did not address the phase delay explicitly but their Fig 2c does not seem to show signs of the required time lag (2 yrs+) throughout most of their period (1959-2004) except at the extremities (1959-1963) and (2000-2004) in the middle part it appears to be closer to 1 yr. (This is just my eye-balling)

    If this is the case it has serious implications for even their simple model. It would put their factor of 3 for the attenuation as an upper limit and it will in turn give an upper limit 5 yrs to their time constant. They prefer a range (6-12 yrs).

    I believe that if they looked at both aspects of their model (amplitude and phase) they might come to the conclusion that they give contradictory results. They might be wise to consider whether this is due to the data or the inadequacies of the model.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 29 Nov 2007 @ 9:48 AM

  87. Re Craig Allen @ 81: “Within a month or two, the US will be the only hold-out on Kyoto.”

    Not quite, the minority Conservative Harper government in Canada is still very much “holding out,” having stated that although Canada signed Kyoto, it can not and will not meet its Kyoto commitment, having never seriously made any attempt to do so under the past two Liberal governments.

    Comment by Jim Eager — 29 Nov 2007 @ 11:05 AM

  88. Re: Ray #85,

    The paper William references appeared in the book: “Solar Variability and its Effects on Climate” published by the AGU in 2004.

    Comment by Robert A. Rohde — 29 Nov 2007 @ 12:11 PM

  89. For what it is worth which is probably not much I have had a look at the NOAA temperature data for 1980-2002 (all.land_and_ocean.90S.90N.dat) hopefully this is a good source.

    It is relatively easy to find a ~0.1C pk-pk signal but it peaks around (1989/1990) and (2000/2001) and troughs around (1984) and (1995/1996) which I guess makes it in phase with the solar cycle (actually slightly leading). Not I feel an answer that would please them.

    There is another snag. We only have two cycles so the resolving power is very small. The 11 cycle is not at a spectral peak which in fact occurs at ~8.5yrs ~0.15C pk-pk. Such peaks can occur for no apparent reason they are commonly just happenstance but 11yrs is too close to 8.5yrs to be resolved seperately with just 22yrs of data. So maybe there is a signal or maybe there is not.

    BTW I tried the same trick as Tung & Camp in order to account for volcanoes (remove the data for 1982/83 and 1992/93) which are perilously close to and 11yr periodic forcing but it made only a small difference putting the peak about 6 months to 1 years later (where I have given a second figure above it is for the “devulcanoed” data).

    Best Wishes

    Alex Harvey

    Comment by Alexander Harvey — 29 Nov 2007 @ 1:02 PM

  90. I would be obliged for a correction I used

    monthly.land_and_ocean.90S.90N.df_1901-2000mean.dat

    not the data dataset I mentioned.

    Comment by Alexander Harvey — 29 Nov 2007 @ 1:05 PM

  91. Re: #78 (William Astley)

    Solar minimums have been shown to occur every 200 years and the Dalton minimum was 200 years ago

    I’m highly skeptical of this claim. One of the most common mistakes made by scientists in data analysis is to attribute periodicity to time series when the data don’t really support that conclusion. Considering that we have a mere 400 years of sunspot data to work with, the evidence for a genuine 200-year periodicity is flimsy — at best. And considering Svensmark’s well-founded contention that changes in solar-cycle intensity do *not* correspond to changes in climate-relevant solar activity, claims that reduced solar activity will lead to cooling, or even that “We should have an opportunity to determine how much of the 20th century warming was attributable to solar as compared GWG, if the solar minimum occurs starting cycle 24,” are premature — at best.

    Comment by tamino — 29 Nov 2007 @ 1:27 PM

  92. GREAT fun video on global warming
    http://www.youtube.com/watch?v=5SiEm2akhrc
    http://www.globalwarmingguy.com

    Comment by william — 29 Nov 2007 @ 2:16 PM

  93. I have to confess that I find this paper opaque.

    Can someone tell me if have they divided the Moberg temperature change 1700-1900 (~0.3C) by the Wang TSI increment for that period (~.5 W/m^2) to get (0.65 +/-0.28 K m^2/W).

    I.E are the sensitivities rated against Insolation in space?

    I am not sure of the exact relation but to get to a standard forcing from TSI you have to divide by 4 for the spherical geometry of the rotating earth, multiple by ~0.9 (ish) for UV absoprtion above the tropospere multiple by ~0.7 to allow for albedo.

    Do that and 0.65 becomes ~4.1 K/(W/m^2).

    Perhaps I am having one of my bad days but it really looks like they are quoting K/TSI which need converting by a factor of about 6 to get the corresponding sensitivity.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 29 Nov 2007 @ 2:36 PM

  94. Small correction: they use the their wierd estimator which for Moberg gives 2*.186 = 0.372K but it does not change my point.

    Comment by Alexander Harvey — 29 Nov 2007 @ 2:46 PM

  95. In reply to Tamino’s comment:

    “I’m highly skeptical of this claim. One of the most common mistakes made by scientists in data analysis is to attribute periodicity to time series when the data don’t really support that conclusion. Considering that we have a mere 400 years of sunspot data to work with, the evidence for a genuine 200-year periodicity is flimsy — at best.”

    The following is 1200 year evidence of a 200 year solar cycle.

    http://www.springerlink.com/index/V544315804280142.pdf

    200-year variations in cosmic rays modulated by solar activity and their climatic response

    Manifestation of the 200-year solar cycle (de Vries cycle) in climatic changes (summer temperatures) has been investigated by analyzing the radial growth of long-lived (800–1200 yr) ….Quasi-two-hundred-year variations in the radial growth of trees have been revealed, which correlate well (correlation coefficient reaches 0.94) with similar solar activity variations (Δ14C).

    http://linkinghub.elsevier.com/retrieve/pii/S1364682698001424

    In reply to Tamino’s other comment concerning Svensmark. Svensmark’s papers and his book state that there would be a significant cooling resulting from a solar minimum.

    There are three methods in which solar changes affect climate. Electroscavenging that removes cloud forming ions. Electroscavenging is caused by high speed solar wind bursts. Changes in the solar heliosphere. The heliosphere takes roughly two years to reach equilibrium after a step change. Changes in the TSI.

    In reply to Ray Lambury,
    There is a disagreement as to how much of the 20th century warming was due to solar modulation of clouds and TSI changes and how much was due to GWG.

    A set change in solar modulation of clouds and TSI will enable that question to be resolved.

    Comment by William Astley — 29 Nov 2007 @ 2:52 PM

  96. Re: #95 (William Astley)

    I have studied in great detail the variations of cosmogenic isotopes, and a large number of research papers which claim to establish numerous periodicities using them as a proxy for solar variations. It is precisely because of this detailed study that I am skeptical of the validity of claims of periodic fluctuations. As I said before, one of the most common mistakes made by scientists in data analysis is to attribute periodicity to time series when the data don’t really support that conclusion. You have simply pointed to examples of this.

    I remain highly skeptical that solar minima occur every 200 years.

    Svensmark will be presenting his evidence that climate-relevant solar variations to not follow variations in sunspot cycle intensity in about a week at the AGU meeting.

    Comment by tamino — 29 Nov 2007 @ 5:21 PM

  97. Re: #96 (me)

    Oops! It’s not Svensmark — it’s Svalgaard.

    Comment by tamino — 29 Nov 2007 @ 5:43 PM

  98. The S&W paper states,in part, on P.4:”[23] The second independent constraint reflects the
    hypothesis that the secular TSI increase during the preindustrial
    era is responsible for the contemporary observed
    increase of global surface temperature. (In the Conclusion we discuss the limitation of this assumption.)”

    Then in the conclusion are the statements:” On the other hand, if a secular temperature
    showing large preindustrial variability is adopted, such as
    MOBERG05, the climate is found to be very sensitive to
    solar changes and a significant fraction of the global
    warming that occurred during last century should be solar induced.”

    And further on:”Some climate model studies [Shindell et al., 2003] have
    reported that on a secular scale the volcano forcing had the
    same order of magnitude as solar forcing, other studies
    would present a wide range of relative contributions.
    [40] Therefore our estimates about the solar effect on
    climate might be overestimated and should be considered as an upper limit.”

    All of this sounds to me like quite a stretch!I’m referring to their hypothesis that the TSI activity during the pre-industrial period, some 250 years ago and beyond, has a non neglible effect on the global climate change being seen today! Can this be?!

    [Response: Not to defend S&W, which is really quite full of nonsense, but I think you are misconstruing their argument in this instance. I believe they are making a statement about estimating climate sensitivity to solar forcing by using the pre-industrial fluctuations; they are not arguing for a direct lagged effect of solar forcing 250 years ago. If a climate reconstruction like Moberg's, with a lot of variability, were right, you'd need a high sensitivity to solar forcing in order to account for it. Then, take that high sensitivity into the post-industrial era, and you get a lot of solar response then, part of which correlates with the observed temperature. What's left over is what you explain by CO2. (in the twisted physics-free world Scafetta and West inhabit). Now, in a physics-full world, the problem you have with that argument is that if the climate is so terribly sensitive to radiative forcing by the weak solar variability, you ought to get a truly humongous response to CO2-- which wouldn't match the observed temperature record. In the physics-lite world of Scafetta and West, this is gotten around by assuming the sensitivity to radiative forcing by CO2 is a parameter that can be twiddled independently from sensitivity to solar forcing. What they probably have in mind is some variant of the cosmic ray modulation of clouds. Fine, if that's what they want, but this has got to be considered rank speculation until there's some quantified treatment of the radiative forcing by the purported cosmic ray effect. And if they are invoking some kind of stabilizing cloud or water vapor feedback to damp down the CO2 sensitivity, they've got to consistently apply that damping to any radiative forcing coming from the solar-related modulation of clouds as well. --raypierre]

    BTW Moe Berg( who I’m sure has nothing to do with the naming of the model), a major league catcher for ~15 years, and then a spy during WW2,is also known for his statement saying that a catcher’s equipment are “the tools of ignorance”. Well, tools are neither intelligent nor ignorant, but in the hands of the untrained or the mischievous, they can be useless or even detrimental. This may well apply to the S&W paper.

    Comment by Lawrence Brown — 29 Nov 2007 @ 6:48 PM

  99. I agree with Tamino (#96). While solar activity definitely fluctuates, there is little compelling evidence of true periodicity. The direct records are too short to establish long-term periodicity, and the proxy records of solar variability (e.g. C-14, Be-10) look like red noise. In other words, you’d expect a similar pattern if the intensity simply fluctuated up and down in a random walk. Sometimes, merely by chance, there would be intervals of apparent periodicity, but those intervals generally don’t persist over the long-term.

    That said, I would still suspect that solar intensity would likely decline during this century, if only because the current intensity appears unusually high by historical standards.

    Comment by Robert A. Rohde — 29 Nov 2007 @ 7:01 PM

  100. Those looking for a bit of fun might want to read the recent CA post on S+W 2007, beginning with Svalgaard’s first comment at about #65. The writhings of the solarphiles are a sight to behold. McIntyre doesn’t sound too happy himself, which I suppose is understandable given that so much of his support base is composed of people who *know* that it just has to be the sun. Of course if Svalgaard is correct (and BTW he seems to have a lot of support from other solar physicists), there may be some unsalubrious implications for McIntyre’s own efforts to plump up the MWP and LIA.

    Comment by Steve Bloom — 29 Nov 2007 @ 7:18 PM

  101. Off-topic, but I now have a minor interest in inter-ocean transfers of water via rain or snowfall. Divide the world’s ocean into just the Atlantic (includes Caribbean, Mediterranean and Arctic) and the Indio-Pacific (plus maybe the Southern Ocean?). Now fairly clearly around Central America it seems that there would be evaporation in the Caribbean with some of the rainfall on the Pacific side of the continental divide. Here in the Pacific Northwest, evaporation in the North Pacific leads to some of the rain and snow on the east side of the continental divide.

    I know essentially nothing about how this plays out in Africa, and in any case don’t seem to know appropriate search terms to aid me in this little exercise. Any assistance will be appreciated. :-)

    Comment by David B. Benson — 29 Nov 2007 @ 7:38 PM

  102. #96 (Tamino) So, the “proof” that there’s no quasi-200 yr solar cycles is… that too many scientists find this cycle when filtering their data ? Hard for me to understand your point, because witjout more precise critics of proxy analysis, this kind of “prior assumption suspicion” may be adressed to any research in any field of climate science. Muscheler, who have been guess author here, have no problem with this periodicity when revieweing the relevant studies (Cl36 and Be10 in ice core, C14 in tree ring, etc.). See for example his contribution (with Beer and Kubik) in Pap et Fox (ed), Solar variability and its effects on climate, AGU, 2005, pp. 221-236.

    I have a question about solar forcing trend. On NCDC paleoclimate database, I download Mike Mann et al. volcanic and solar forcing on Tropical Pacific for the last 1000 yrs. (J Clim 2005). But the highest value of the solar-forcing serie, 0,423, is given for 1989, not far from the second highest 0,418 (1990) and post-1980 values ar globally higher than all pevious, for the XXth century or past millenia.

    How is it possible to get such a hight solar signal on Tropics if there’s no global trend in the past 50 yrs ?

    Ref :
    http://www.ncdc.noaa.gov/paleo/forcing.html
    ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/mann2005/

    [Response: You are aware that these are simply the Crowley (2000) estimates (which are a splice of cosmogenic isotope and sunspot-based solar reconstructions), scaled by a constant geometric factor to account for the difference between equatorial and hemispheric-mean insolation? While the values indeed peak in the 1980s, the trend over the past few decades (including the most recent solar cycle, which is largely subsequent to the 1999 termination of the Crowley series) is not statistically significant. -mike]

    Comment by Charles Muller — 29 Nov 2007 @ 9:50 PM

  103. ciao, Rasmus and Gavin. How are you? I hope well.

    [Response: Fine - We are ready for an exciting debate! -rasmus]

    I see that Rasmus has once again written an interesting article on our research. I sincerely suggest Rasmus to be more relaxed when he writes something. I do not undestand why it is not possible to the writers of this web site to give a fair and calm reading of a paper and only after then to write an interesting and useful critique.

    The arguments made by Rasmus are quite wrong on several grounds:

    A) He claims that I did wrong calculations because in his opinion our evaluation of the warming from 1900 to 2005 of 0.8K is too small. Well, around 1900 the average temperature anomaly was -0.3K and around 2005 the average was 0.5K. The sum is 0.8K, right? Rasmus is considering the extreme of the fluctuations seen in the temperature, instead of looking at some mean value.

    [Response: When discussing long-term changes for series with year-to-year variations, you need to do a proper trend-analysis, rather than just pick a single year. Just look at your graph, and you see that it's not representative for the development. -rasmus]

    B) The issue of the cooling between 1940 to 1970. Rasmus claim that our paper is wrong because I do not recover 100% of this cooling. Well, first, as some readers above have noticed, this is a problem also for the GCMs guys because these models such as the GISS one fail to reproducing this cooling too. The GCMs guy claim that this cooling was cause by an increase of aerosol in the athmosphere (not well documented, actually). Fine. So, why this cannot be true also for our study? I have never claimed that the Sun explains 100% of the patterns seen in the temperature record since 1900. So, Rasmus argument is quite unfair, as the readers can easily undestand.

    Observed global mean T and corresponding results from GISS GCM - tests ignoring GHG.Observed global mean T and corresponding results from GISS GCM - tests ignoring TSI.

    [Response: The problem with this paper is that it claims both a dominant role for the sun in addition to a long relaxation time. That combination doesn't work when looking at the temperature evolution, as most (almost all) of the solar activity changes happened before 1950. About your comment that the GISS model fails to reproduce the levelling off: Actually, the levelling off/cooling period is quite well reproduced by the GISS-model (see above Figures and FAQ 8.1 Figure 1 on p. 600 from the IPCC WG1 AR4). I don't think that you are up to date! You are right that there are considerable uncertainties associated with aerosols, and aerosols should also be one of the factors of your study. Likewise, so should GHGs. But do you really believe that the relaxation time for these forcings are much shorter than for solar forcing? After all, the alleged effect from aerosols appear to produce quite rapid changes compared to the long time scales you claim to be at work. And are you admitting that aerosols have a much stronger effect masking a solar signal? -rasmus]

    However, there might be another explanation I wrote in the paper, that Rasmus in his impetus has missed again. In fact, I used the TSI proxy reconstructions by Lean. These reconstructions reproduce the secular solar trend with the geomagnetic and smooth sunspot record. These records pick around 1960. However, other solar observables, such as the solar cycle length picks in the 1940s and then decrease untill the 1970s. Perhaps, the sun followed this proxy better, as assumed by Hoyt and Schatten in ther TSI reconstruction and picked in the 1940s when there was a temperature maximum is observed. This might explain the 1940-1970 cooling with a solar decrease that is only partially recovered when I use the Lean’s reconstruction. So, I believe that this issue about the correct TSI reconstruction, which is not solved yet, merits a deeper study. However, this is said in our paper and in the previous papers, and also several times in this web-site in response to Rasmus. Rasmus always repeats the same point and never listen!

    Figure 2 from Benestad (2005)

    [Response: Actually, the solar cycle length (SCL) really doesn't 'peak' in the 1940s - look at the figure on the left (Fig 2 from Benestad (2005)). Only a traditional method of estimating SCL directly from the Wolf sunspot number (not recommended as it involves high degree of uncertainty) yields anything that can be interpreted as a 'dip' around 1940 (when you invert it a 'dip' becomes a 'peak'). Or perhaps you are referring to those filtered curves by Friis-Christensen & Lassen (1991) which since have been discredited? But even if you were to use SCL and it did peak in 1940, a hypothetical solar response would, according to your work, be delayed. But it's a bit dodgy to throw in different indices to the equation without a clear physical understanding for why they should be more appropriate than the others. Also, it's interesting to note that there are discrepancies between the different solar proxies - beit TSI, SCL, aa/ak indices, sunpot number, 10.7 cm flux, or magnetic components. It's always possible to do a 'curve-fit' by selecting a suitable time relaxation after searching for a curve that looks a bit similar - and voila! There is a nice fit in the end! But that's not science. Science is about being critical. If you claim there is a relaxation time and a peak in the response, then you imply that the level of solar activity must have dropped quite a bit since some time before 1940. As far as I know, this has not happened. I suspect that if you use Hoyt and Schatten in ther TSI reconstruction instead of Lean TSI, then you don't need any relaxation time, as this would provide a poor fit (the peak would still be delayed). I suggest a read up on Karl Popper. About me not listening - well the fact that I write this post means that I do take some interest in your work and that I do read your papers. The reason why I repeat some points is because you don't learn from our discussions or because you do not convince that the way you do it is correct. I did hope that you put more care in stitching together different series and that you eventually learn that because you find spectral power near 11 years in a time series, it doesn't prove that it's caused by the solar cycle. -rasmus]

    C) the issue between ACRIM and PMOD. I believe that Rasmus is not really understanding the difference between the two. In a few words, both claim to be composites of the TSI satellite data however there is a significant difference. Why is it so? The reason is that ACRIM uses the satellite data as they are published by the experimental groups while PMOD assumes that ACRIM1 and NIMBUS7 data are corrupted and alters them in such a way that the resulting composite looks similar to the TSI proxy reconstruction by Lean. The problem is that the experimental groups which are responsible of both ACRIM1 and NIMBUS7 data do not agree with the PMOD group about the necessity of these corrections. Thus, ACRIM represents the satellite data and is the real composite, while PMOD is a theoretical composite that fits well the TSI proxy reconstructions (that might be wrong!).

    [Response: This is the version I have heard: 'There is reason to doubt that the ACRIM composite is correct - during the 'ACRIM gap', you need to use another source of irradiance data to fill in. Willson using one, Lean+Frohlich use another. The proxy records - 10.7 radio flux, cosmic rays etc all correlate with L+F's choice - not Willson's. But it could still be that there really is an incoherence between the other solar indices at solar min and irradiance - in which case there is no information available prior to the direct measurements that is useful! One final issues is that the nature of the 'trend' even in the ACRIM composite is pretty diffuse. It does not come from any statistical regression, but was simply the difference between the two solar min. With the latest solar min below even the first in all records, there is no sense in which the Willson analysis shows an upward trend. The problem with the SW composites is that a) their Lean + ACRIM record is just made up - Lean's reconstruction is from a model that is tuned to the PMOD composite, not ACRIM - and so there is no real idea of how ACRIM would really effect the reconstruction or the errors, b) as you point out, they have a single factor analysis that will fold any power (from noise, volcanoes, GHG trends) into their assessment of the 'solar' terms.' ]

    In my opinion both composites are important for a study like mine because there might be the possibility that the Earth climate might contain mechanisms sensitive to the pattern observed in PMOD and other mechanisms sensitive to the pattern observed in ACRIM. So perhaps, a more correct result would be some how between the two curves I get.

    [Response: It's a fact that ACRIM differs from the TSI-construction in the period they overlap (otherwise, there would be no point to change the series). This is a clue! Either the ACRIM is wrong or the TSI-construction, and by stitching them together you get an inhomogeneous series which invalidates trend analysis. -rasmus]

    I hope this helps the readers of this forum. Those interested in another different forum on our work can read this:

    http://www.climateaudit.org/?p=2451

    (Rasmus and Gavin, please do not erase the link above, climateaudit links to your web site, it would be kind if you link their)

    [Response: I won't censor your link, but I will dare to be somewhat sarcastic and say that the link is indeed enlightening (not). -rasmus]

    ciao, ciao,
    nicola

    PS: about the F grade Rasmus gave me, I just let the readers notice that it is not fair to be at the same time the accuser and the judge. Rasmus likes to be both. Let Rasmus be the accuser, but let the readers of the debate be the judge, OK?

    [Response: You are right, the readers should judge the material for themselves. -rasmus]

    Merry Christmas to all!!!!

    [Response: Same to you!]

    Comment by nicola scafetta — 29 Nov 2007 @ 10:57 PM

  104. Re: #102 (Charles Muller)

    So, the “proof” that there’s no quasi-200 yr solar cycles is… that too many scientists find this cycle when filtering their data ? Hard for me to understand your point, because witjout more precise critics of proxy analysis, this kind of “prior assumption suspicion” may be adressed to any research in any field of climate science

    First of all, a quasi-200 yr cycle is not a periodic cycle; it’s a variation which happens on a timescale of around 200 years, but is not strictly periodic, its period and amplitude may both be highly variable, it may lose phase coherence altogether, and the fluctuation may be intermittent or even temporary, disappearing for long stretches of time or even forever. I meant just what I said: I remain highly skeptical that solar minima occur every 200 years, which is what William Astley claimed.

    I did not make a “prior assumption of suspicion.” As I already stated, I have actually analyzed much of this data, and reviewed published works. Many analysts have claimed “periods” which are at best pseudoperiods, at worst nothing but noise. For example, the best C14 data of which I’m aware is the INTCAL98 data, for which a large number of authors have claimed a very large number of periods. But when I run the numbers the vast majority of the claimed periods (including that near 200 years) are consistent with psuedoperiodic fluctuation or with nothing more than the spectral signature of red noise. The data are most definitely NOT consistent with a truly periodic phenomenon with period anywhere near 200 yr.

    There may indeed be a roughly 200-yr pseudoperiodic behavior in solar output, but the data I’ve seen indicate that it’s still an open question. And in my opinion, the claim that “solar minima occur every 200 years” is utter nonsense.

    Comment by tamino — 29 Nov 2007 @ 11:50 PM

  105. In reply to Ray Lambury’s comment:

    “Thus, any decrease in solar forcing will buy at most a temporary reprieve (and probably a return to complacency) before the end of the Minimum brings the return of warming with a vengeance. That CO2 is responsible for most of the current warming is really inescapable.”

    Ray you are missing the points. GWG warming is over estimated if solar warming is significantly under estimate. Also I see the problem as eminent global cooling not warming which is consistent with paleoclimatic record. Interglacial periods end abruptly and there is clear unrefutable evidence of periodic abrupt climate changes. Have you ever thought about the glacial portion of the cycle?

    It seems the solar modulation of planetary cloud cover has not been taken into account. i.e. The GWG calculations assume all of the 20th century warming is due to GWG?

    This paper shows that the solar changes which modulate cloud cover correlate with the observed 20 th century temperature changes for the entire period in question.

    http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf

    “We show that the index commonly used for quantifying long-term changes in solar activity, the sunspot number, accounts for only one part of solar activity and using this index leads to the underestimation of the role of solar activity in the global warming in the recent decades. A more suitable index is the geomagnetic activity which reflects all solar activity, and it is highly correlated to global temperature variations in the whole period for which we have data.”

    In Figure 6 the long-term variations in global temperature are compared to the long-term variations in geomagnetic activity as expressed by the ak-index (Nevanlinna and Kataja 2003). The correlation between the two quantities is 0.85 with p

    [Response: I'm a bit skeptical to the figures in that paper - how are the curves smoothed? (they remind me a bit of the work of Svensmark, Friis-Christensen & Lassen). It's also typical - when one index doesn't work, a new one is thrown in. The authors use the ak-index for which they claim describes the geomagnetic field. But it's the interplanetary magnetic field (IMF) - or the magnetic field spanning the solar system - which has been proposed to be important for shielding most of the GCR. The geomagnetic field has little to do with the solar activity, but more to do with earth's crustcore (sorry, got the words mixed up!). It is not clear then why the ak-index should be superior to other indeces. My GRL paper on solar proxies like the aa-index, sunspot number, SCL, and GCR suggest that these have not changed appreciably since the 1950s. also see the posts on 'Comsoclimatology' , and about the spin on GCR, and lack of similar long-term variations between GCR and T. -rasmus]

    Comment by William Astley — 30 Nov 2007 @ 1:26 AM

  106. Many thanks Nicola Scafetta to participate in this discussion (# 103)!

    I forward the readers of this blog to read also ClimateAudit at http://www.climateaudit.org/?p=2451

    and

    Reference Frame at http://motls.blogspot.com/2007/11/scafetta-west-climate-phenomenology.html

    Nicola Scafetta’s comment on the way this blog is run is a good impetus for all readers to read Science Editorial today:

    Sykes, Kathy, 2007. The Quality of Public Dialogue. Science Editorial Vol. 318, No 5855, p. 1349, November 30, 2007

    Extract:

    “…But these dialogues must be of a high standard; otherwise, time is wasted, the public lose trust in science, and bad policy decisions result. So, what constitutes good dialogue?

    Public dialogue is valuable when it helps policy-makers hear the views of people who have no prior or vested interest. It can challenge assumptions, explore long-term impacts, generate ideas, tease out the nature of public concerns before polarized positions emerge, and help broaden consideration of the issues. Dialogue is not about the public making decisions about science policy; that is for policy-makers. Neither is it formal public consultation, nor is it an open platform for debates that can polarize participants or be hijacked by lobby groups or stakeholders (although their perspectives are important to consider)….”

    Well, you surely have yr views whether RealClimate is or not run by “people who have no prior or vested interest” and whether this blog is or not “an open platform for debates that can polarize participants or be hijacked by lobby groups or stakeholders…”

    [Response: But the pages of those links that you provide DO NOT hold a dialogue of high standard. They rather serve to provide ad hominem attacks. The latter, among other things, calls RC a 'propagandistic blog designed to politicize science, a kind of blog that refers to all politically inconvenient scientific results as the "industry-funded misinformation"'. Not much scientific reasoning there. No documentation no proof. Just childish statements taken out of the air. ClimateAudit publishes statements such as '[people at] RealClimate are not scientists at all. They are priests of a mystery cult.’. Or this thing about the ‘penalty box’. Again, childish, and that blog is in a similar category as the former. You surely have yr views whether these sites are or not run by “people who have no prior or vested interest, to use your oewn words? I can assure you that I have neither experienced that RC has been hijacked by lobby groups, stake holders, and that we are open to different views (this is but one example). But perhaps by insisting that we link to those trashy sites, you are trying to hijack our blog? -rasmus]

    Comment by Timo Hämeranta — 30 Nov 2007 @ 5:12 AM

  107. William Astley, your post #105 demonstrates a common misconception among skeptics–namely that if we can just find some other factor that contributes to climate change, then we can forget about CO2. Unfortunately, CO2 forcing is constrained by several independent lines of evidence. There isn’t much wiggle room without having to scrap the whole theory of climate–and since this theory has yielded pretty good qualitative and in many cases quantitative agreement, we have to assume it’s a pretty good theory in its basics. The degree of constraint is much less wrt aerosols, clouds, etc., so these parameters could drift a bit in future models. So if your modulation of cloud cover is correct, the most likely other forcing affected would be aerosols, not CO2, and our problem doesn’t go away. Unfortunately, climate models are not Chinese menus where you pick one from column A and one from column B.
    Moreover, there are reasons to doubt that a cloud modulation mechanism really works–it’s a neat trick to suppress cloud formation during the day when it promotes warming, but not at night when it promotes cooling, for instance. Looking for correlations in data unguided by physics (or using physics a posteriori to explain the correlations) is a fraught proposition–as medical studies demonstrate abundantly. I’ve seen four-sigma signals emerge in channels where they have to be garbage.

    Comment by Ray Ladbury — 30 Nov 2007 @ 8:28 AM

  108. Timo, I wonder why you consider Motl anything but a court jester wrt climate. He has no relevant expertise and merely demonstrates that smart people can be very wrong when they venture outside their narrow realm of expertise. I wonder if you consult him on matters of plumbing and electrical work to your house as well. I also wonder why we are talking about “public debate” wrt the science of climate change. The public really doesn’t get a vote on the science.
    Climate audit has also made itself increasingly irrelevant by continuing to ignore the science. Many on that board are still questioning WHETHER the planet is warming. The level of scientific literacy there is pretty apalling.
    Where the public need to weigh in is wrt what we do about the threat we face. As long as a segment of that public continue to waste time by debating established facts, they disenfranchise themselves from the process of coming up with solutions. In effect, we need the loons on the right to cancel out the loons on the left so the center can make real progress.

    Comment by Ray Ladbury — 30 Nov 2007 @ 8:53 AM

  109. Any public forum needs a killfile. Usenet had threaded reading and killfiles that could remove both individual posters (uniquely identifiable) and entire threads, at each reader’s individual choice.

    One thing we know about all of us — it’s hard to ignore distraction, hard to remain focused on a discussion, unless we can truly not see the attempts to derail and insult and confuse the conversation. Being human means being easily trolled. We rise to bait, even with the best self control.

    This is why we don’t do important work in hostile crowds, except on the Web that’s hard to avoid, while we are still lacking Usenet’s capable tools for talking only among those willing and able to contribute toward making progress in understanding the topic.

    “Don’t criticize what you can’t understand” is advice rarely taken.

    Comment by Hank Roberts — 30 Nov 2007 @ 9:27 AM

  110. In reply to Ramus’ comment:

    “It is not clear then why the ak-index should be superior to other indices.”

    The ak index (which measures the affect of the solar wind on the geomagnetic field) is used rather than aa as the 20th century 1991 to 2007 reduction in planetary cloud cover is due to electroscavenging not due to decreasing levels of GCR. The electroscavenging is caused by high speed solar wind bursts, from coronal holes. The coronal holes move to the solar equator at the end of solar cycles 21, 22, 23. As noted in Georgieva, Bianchi, and Kirov’s in their 2005 published paper the aa index and a simple count of sunspots does not correlate with the change in planetary temperature, 1992 to 2001. The problem is the aa index or a simple sunspot count does not measure the parameter which causes electroscavenging.

    http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf

    The electroscavenging mechanism at the end of the solar cycle removes the extra ion cloud forming ions including extra ions that are produced at the end of the solar cycle by the increase in GCR. As you state the heliosphere is reduced at the end of the solar cycle, hence GCR increases. The electroscavenging mechanism explains why there is less cloud modulation variance from solar cycle peak to solar cycle minimum for cycle 21, 22, 23.

    Palle’s earthshine and satellite data and analysis supports the reduction in planetary cloud, 1992 to 2001. Palle notes in his satellite paper that the reduction in cloud cover is consistent with Tinsley’s electroscavenging mechanism. (Electroscavenging reduces cloud cover at specific latitudes. Palle found the reduction in cloud cover occurred at the latitudes as predicted by Tinsley.)

    The following is Palle’s earth shine paper that notes the change in planetary albedo is an observed 7.5 W/m^2 which supports a large solar impact on 20 th century temperature.

    http://solar.njit.edu/preprints/palle1266.pdf

    Our simulations suggest a surface average forcing at the top of the atmosphere, coming only from changes in the albedo from 1994/1995 to 1999/2001, of 2.7 +/- 1.4 W/m^2 (Palle et al., 2003), while observations give 7.5 -/+ 2.4 W/m^2. The Intergovernmental Panel on Climate Change (IPCC, 1995) argues for a comparably sized 2.4 W/m^2 increase in forcing, which is attributed to greenhouse gas forcing since 1850.

    The analysis concerning electroscavenging occurred in the last 5 years. Here is a paper written (1998) before the electroscavenging mechanism was known or at least the authors of the 1998 paper appear to be not aware of it. The authors of this 1998 paper expect the solar influence on climate should be greater than observed based on the aa index.

    http://adsabs.harvard.edu/abs/1998GeoRL..25.1035C

    Nevertheless, the general similarity in the time-variation of Earth’s surface temperature and the low-frequency or secular component of the aa index over the last ~120 years supports other studies that indicate a more significant role for solar variability in climate change on decadal and century time-scales than has previously been supposed. The most recent aa data for the current solar minimum suggest that the long-term component of solar forcing will level off or decline during the coming solar cycle.

    Comment by William Astley — 30 Nov 2007 @ 10:46 AM

  111. In # 98 Raypierre responds:["Response: Not to defend S&W, which is really quite full of nonsense, but I think you are misconstruing their argument in this instance. I believe they are making a statement about estimating climate sensitivity to solar forcing by using the pre-industrial fluctuations; they are not arguing for a direct lagged effect of solar forcing 250 years ago. If a climate reconstruction like Moberg’s, with a lot of variability, were right, you’d need a high sensitivity to solar forcing in order to account for it. Then, take that high sensitivity into the post-industrial era, and you get a lot of solar response then, part of which correlates with the observed temperature."..........]

    Thank you for the clarification. I thought I must be reading too much into it. It was admittedly a painstaking slog, reading through and trying to comprehend a number of aspects of the paper.Now I can go over it again with a better understanding of the underlying principles. I still feel,though, that models are very useful tools, but can sometimes be misused and/or abused and deserve close scrutiny. I’ll leave it to more authoritative and trained minds,in this discipline, to judge whether it’s true,or not, in this case.

    Comment by Lawrence Brown — 30 Nov 2007 @ 11:09 AM

  112. #102 (Mike answer, and broader questions)

    Thank you for the precision, Mike, but I’m still perplex on the issue. I try to explain the point as I undestand it, but please correct all the wrong assertions.

    1. Direct measures of TSI by satellite began only in 1980 (cycle 21 > cycle 23). We’ve two main compostites – PMOD by Frohlich et Locwood, ACRIM by Willson et Mordvinov. Because of a satellite problem and data gap, they differ slightly.

    2. Estimates of long term solar varibility (secular to millenia) are based on previous measures (like 10,7 radio flux, aa index), historical data (sunspot numbers, observed radius) or cosmogonic isotopes (C14, Be10, Cl36, Ti44, etc.).

    3. Quality of long term solar variability reconstructions depends of the quality / reliability of proxies. The only way to evaluate that is to develop a solar model (eg SATIRE of Solanki team) based on 1980-present precise measurements, and to observe how TSI variation in a cycle (or between cycles) correlates with magnetic / cosmogenic / historical variations. From such a model, it is possible to re-estimate more precisely the solar variability of past 100, 1000 or 10,000 yrs.

    ***

    From these three points (if correct), my questions :

    - Are reconstructions like Crowley 2000 still valuable today (I suppose, because Mike used it in his 2005 paper) ? More broadly, which are the supposed better reconstructions (that is better fit with instrumetal measure of TSI since 1980)?

    - On Crowley 2000 reconstruction, what is the correct evaluation for the trend and its significativity? An example : the 1910-1939 mean is 0,218 W/m2, the 1940-1969 mean is 0,269 W/m2 and the 1970-1999 mean is 0,322 W/m2. So, these 30yrs mean give an increasing trend, even the second half of the Century (contrary to the supposed “no trend” since 1960 RC often quotes). Of course, the trend is small… but anyway, everybody agrees now that solar TSI trends are weak since 1750 or 1900 (cf. the 0,12 W/m2 for 1750-present solar forcing in AR4 IPCC, adn the table 2.10 for the different reconstructions from Maunder minimum to present minima). It is precisely because the TSI trend seems weaker than previousley assessed that scientists look for indirect effects of solar forcing on climate. No ?

    ***

    #104 Urs : thank you for your precision, and I agree with them. I don’t know if William Astley had in mind a strict 200 years cyclicity. I read in some papers (Solanki if I recall correctly) that solar activity should decrease in this century after XXth C maximum, but without any precision on the timing of this decrease and without any allusion to a “grand minimum” of Maunder-type.

    Comment by Charles Muller — 30 Nov 2007 @ 11:14 AM

  113. In response to Ray Ladbury’s comment.

    “William.., your post #105 demonstrates a common misconception among skeptics–namely that if we can just find some other factor that contributes to climate change, then we can forget about CO2. …Unfortunately, climate models are not Chinese menus where you pick one from column A and one from column B.”

    1) I unequivocally support conservation and responsible development. Please do not me names.

    2) There is evidence throughout the glacial periods and the last interglacial period of abrupt cooling, which is also climate change. Solar modulation of cloud cover and change in TSI would explain the past abrupt cooling. There are a number of papers that support the solar modulation of cloud hypothesis. I am interested in all scientific research concerning climate change not just GWG.

    3) Do you have any comments re: Palle’s earthshine data and analysis concerning planetary cloud cover. (see my comment 110.)

    4) I thought the climate models have an acknowledged problem with modeling cloud cover. I do not understand your comment concerning Chinese menus and climate models. The two seem to be unrelated.

    Comment by William Astley — 30 Nov 2007 @ 11:52 AM

  114. Re 82 (Robert)
    Solanki and Krivova made one clear assumption (that all global temperature variability form 1860-1970 is explained by solar variability) which, although very unlikely, allows a clear interpretation of the results.
    The SW paper mixes such a number of assumptions, which are unlikely and some of them physically questionable, that a meaningful interpretation of the result is impossible.
    I do not reject a paper because of its results but because of the way the results are achieved.

    Comment by Urs Neu — 30 Nov 2007 @ 11:53 AM

  115. William Astley writes:

    [[ GWG warming is over estimated if solar warming is significantly under estimate.]]

    Nope. You’re missing a basic principle here. The radiative forcing of one is not affected by the radiative forcing of another. They are each computed from first principles. Neither is the residual for the other.

    Comment by Barton Paul Levenson — 30 Nov 2007 @ 12:36 PM

  116. #106 Rasmus Comment

    It seems the ak index have been proposed by Nevanlinna, H. and Ketola, A., 1993. Do you know (or somebody here) the difference with aa index ?

    On this Finnish URL, I just find the precision : The Ak(Hel) index measuring the geomagnetic activity was created by Nevanlinna and Ketola (1993). It has been adjusted with the aa index to form the longest uniform index of global geomagnetic activity, extending over the last 14 solar cycles (Nevanlinna and Kataja, 1993).
    http://www.oulu.fi/~spaceweb/textbook/indices.html

    ***

    You say : The geomagnetic field has little to do with the solar activity, but more to do with earth’s crust.

    For an oppositive view (geomagnetic index as proxy of solar activity), see Le Mouel et al. 2005 :
    http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V61-4FV9MMT-1&_user=10&_coverDate=04%2F15%2F2005&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=e35256660478dac919c7311ee59cbe84

    And Courtillot 2007 (I leave this one because raypierre should comment it in his part II of Chevaliers de la Terre Plate – you know, the nice piece from Les Chevaliers du Soleil Calme :D)

    Comment by Charles Muller — 30 Nov 2007 @ 12:52 PM

  117. Two other questions :

    - is there an ftp access for Wang, Lean and Shelley 2005 reconstruction data (latest update of Lean 1995 and Lean 2000) ?

    - Nicola (if you read), did you try the same work with Fligge 2000, Krivova 2003 or Foster 2004 solar reconstructions, a bi more pronounced than Wang et Lean, and if so did you find the same solar signal ?

    Comment by Charles Muller — 30 Nov 2007 @ 1:08 PM

  118. William, I’m not sure which Palle study you mean, as 110 is not one of your comments. However, I am somewhat familiar with Palle’s work. First, it’s not uncontroversial, and even if it is confirmed, there are question about how important it might be. One problem is that clouds both reflect and insulate. The two effects tend to cancel out–hence my comment about getting clouds to form only at night is a neat trick. Again, keep in mind that just finding another heat source won’t absolve CO2. You also have to show how so many different lines of evidence supporting current estimates of CO2 forcing could be wrong.

    Comment by Ray Ladbury — 30 Nov 2007 @ 2:13 PM

  119. Gavin Your:

    “Arrggh! The whole point of the ‘mainstream’ view is that you are not going to get very far with simple one-factor correlations. It doesn’t work for solar, and it doesn’t work for CO2 either – too many of the forcings are correlated. You absolutely need to use all major forcings before you can do an attribution. When you do that, GHGs are very likely responsible for the rise in recent decades.”

    Gavin please excuse me if I elaborate:

    What we risk is the tyranny of non-orthogonal functions competing for first position.

    If (just being impartial) TSI is the primary driver and correlates well with the temperature record we need to consider just how well it compares with other forcings. There is a temptation to take your preferred function, ascertain its correlation, calculate the optimal multiplier of this function, subtract the explained element from the temperature record and say: “whatever is left is all that competing functions can explain”.

    As you say. No! If the candidate functions are correlated you simply cannot do that.

    For simplicity we can begin with just two competing functions A and B.

    If they are non-orthogonal, (their dot product is not zero), then one can proceed by constructing two new functions (A+B) and (A-B) which are orthogonal (where A and B are normalised i.e their mean = 0 and their variance = 1).

    Do this and the (A-B) vector discriminates between the relative contribution of A and B.

    Do the calculations and optimal values for the contributions of A and B emerge.

    If having done this the remaining unexplained variance is zero you can stop.

    If it is not zero the optimal values are not the absolute result. Other functions will have to be investigated and the are also likely not to be orthogonal to the original functions. New orthogonal functions will have to be generated, new dot products found, new calculations made and new optimal allocations amongst the candidate functions found.

    This has to continue until all residual variance is removed or a declaration of noise is made.

    To assume that a single function can be considered by itself is only valid if the residual variance is then zero or can confidently determined as noise.

    I hope that you agree and I have not made more or less of your comment than you intended.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 30 Nov 2007 @ 4:14 PM

  120. William Astley (#112) wrote:

    1) I unequivocally support conservation and responsible development. Please do not me names.

    If one refers to you as a “skeptic,” that is actually at worse a neutral term, and I suspect an inaccurate one. But it is generally what they prefer.

    William Astley (#112) wrote:

    2) There is evidence throughout the glacial periods and the last interglacial period of abrupt cooling, which is also climate change. Solar modulation of cloud cover and change in TSI would explain the past abrupt cooling. There are a number of papers that support the solar modulation of cloud hypothesis. I am interested in all scientific research concerning climate change not just GWG.

    Abrupt climate change resulting in drastic cooling?

    Local abrupt climate change. Bipolar seasaw. Greenland suddenly warms by ten degrees Celsius or more within a matter of decades while Antarctica undergoes somewhat slower warming. Heinrich events. Can’t be explained by solar variability per se since it has effects which are in opposite directions in the two hemispheres. It would appear to be due to change in the modality of the ocean where ocean circulation flips between two modes.

    The only way the models were able to get Greenland to warm like that was with bipolarity — and strong paleoclimate evidence shows that this is exactly what is happening. In essence, the models predicted the bipolarity, and that prediction was a success.

    Beyond such local events, what we see in the paleoclimate record on a global scale is sudden warming followed by a gradual cooling that takes about a hundred thousand years. Orbital variation is getting amplified by the albedo effect and the reduced capacity of the ocean to retain carbon dioxide. But the albedo effect wouldn’t explain the asymetry between sudden warming and gradual cooling. The role of carbon dioxide does given that it is only gradually reabsorbed and mineralized by the climate system.

    But this isn’t why we know that carbon dioxide plays such a role. The forcing due to carbon dioxide is the result of its spectral properties which are virtually derivable from first principles — quantum mechanics — and the distribution of carbon dioxide in the atmospheric column — which is well known. But the extent to which this gets amplified by various feedbacks in the climate system (roughly by a factor of three) is more uncertain — although now we have roughly half a million years of paleoclimate evidence (and other evidence) which puts it at about 3 Celsius per doubling.

    Thus for example, when one tries to make the climate system more sensitive to solar insulation by raising the climate sensitivity to forcing, one also makes it more sensitive to variation in levels of carbon dioxide. Not much that can be done there. Additionally even if one were to find some other mechanism, one would still be left with the problem of explaining why carbon dioxide does not have the effect upon the climate system that it does — given its spectral properties and distribution within the atmospheric column.

    William Astley (#112) wrote:

    3) Do you have any comments re: Palle’s earthshine data and analysis concerning planetary cloud cover. (see my comment 110.)

    I don’t know much about it as of yet, not enough to say its the typical shoddy science coming out of the skeptics corner.

    William Astley (#112) wrote:

    4) I thought the climate models have an acknowledged problem with modeling cloud cover. I do not understand your comment concerning Chinese menus and climate models. The two seem to be unrelated.

    Increased cloud cover raising the albedo with warming would be a negative feedback. Decreased cloud cover (where the cloud cover has its own greenhouse effect) with warming would be a negative feedback. But increased cloud cover with warming raising the cloud-associated greenhouse effect would be a positive feedback. Likewise, decreased cloud cover with warming lowering the albedo would be a positive feedback.

    The questions are: (a) which effect of clouds is stronger – the greenhouse effect or albedo effect?; and, (b) does warming increase or decrease cloud cover? And while Christy for example dances around the following issue, here it is: cloud cover is going to be a function of forcing, whether it is solar forcing or carbon dioxide forcing. So for those who would explain why carbon dioxide doesn’t have the effect that it does by means of negative feedback, the same thing will apply to forcing by solar insulation.

    Finally, with regard to the “Chinese menu” comment, it means essentially that there are multiple forcings and these will be amplified the essentially the same way by the climate system. And one does not get rid of the role of carbon dioxide simply by associating a greater climate sensitivity to solar variability. And at a more basic level, it means that we aren’t facing a choice between solar variablity models vs. enhanced greenhouse models. Both solar variability and the effects of greenhouse gases are a part of climate models, and they have been from the beginning.

    We explain the trend in twentieth century temperatures by means of both, although relative to 1880, for all but one year (1881), best estimates are that well-mixed greenhouse gases (mainly carbon dioxide, methane and nitrous oxide) have had a greater forcing than solar insulation. But the evidence suggests that now just carbon dioxide considered by itself (due to its accumulation in the atmosphere, with roughly 2 kilograms per square meter of anthropogenic carbon dioxide directly above your head) has had a greater forcing relative to 1880 than solar variaibility, and has since the late 1970s.

    As such, when you stated:

    It seems the solar modulation of planetary cloud cover has not been taken into account. i.e. The GWG calculations assume all of the 20th century warming is due to GWG?

    William Astley, 105

    … the second sentence indicates that you really do not know what you are talking about, and furthermore suggests that you have fallen for politically-motivated propaganda that is part of a concerted attack upon climate science. This might also help to explain why you didn’t know about the bipolarity of Heinrich events: the people that you have been listening to would appear to be cherry-picking the evidence, presenting only the evidence which tends to support their views and ignore the evidence which demonstrates that their arguments don’t hold water.

    Comment by Timothy Chase — 30 Nov 2007 @ 4:36 PM

  121. Re: #120 (Timothy Chase)

    Orbital variation is getting amplified by the albedo effect and the reduced capacity of the ocean to retain carbon dioxide. But the albedo effect wouldn’t explain the asymetry between sudden warming and gradual cooling.

    I was under the impression that the chief reason for the asymmetry in glacial cycles (deglaciation faster than glaciation) is that the accumulation of ice sheets is necessarily slow (one snowflake at a time) while wasting of ice sheets can happen much faster, including both mechanically (big chunks break off) and and thermodynamically.

    Who’s the resident ice age expert at RC?

    Comment by tamino — 30 Nov 2007 @ 5:36 PM

  122. Hello Charles,

    In reply to your comment 112:
    “I don’t know if William …had in mind a strict 200 years cyclicity.”

    The solar Maunder like minimums do appear to follow a 200 year cycle. (Hence it is fairly easy to predict a Maunder Minimum, but difficult to predict the magnitude of each solar cycle. One is a chaotic process the other is due to a cyclic interruption.) The characteristics/features of the specific Maunder minimum appear to depend on chaotic processes or what state the sun has at the time of interruption. i.e. A Maunder minimum is a cycle interruption as opposed to a slow down. (See below for details.)

    The following is what I could find out concerning the solar magnetic field generation mechanism and what causes a Maunder minimum. Solar observations support Gene Parker’s hypothesis that the sunspot magnetic field is generated at the tacholine, the region of the sun where there is a change from the radiative zone to the convection zone. The magnetic fields generated at the tacholine rise through the convection zone to the solar surface, where they are removed by the solar magnetic cycle. A large sunspot has a measured magnetic field strength of around 3000 gauss, as compared to the earth’s magnetic field strength of 0.5 gauss. Theoretical calculations indicate that a magnetic field of up to 100,000 gauss can be generated at the tacholine.

    In the normal solar cycle the magnetic fields generated at the tacholine rise to the surface before reaching a 100,000 gauss. The past solar cycle is hypothesized to act as a seed for the next cycle. If the magnetic field generation at the tacholine is interrupted, the past solar cycle no longer interacts at the tacholine. Hence, solar models of the normal solar cycle which use features of the past solar cycle for normal solar cycle predictions are not useful to predict the length and severity of the deep solar magnetic minimum.

    This is one of a number of papers I found that predict a Maunder type minimum. Of course time will tell, however the Maunder minimums have in the past been cyclical.

    http://adsabs.harvard.edu/abs/2003SPD….34.0603S

    “Long-range (my comment: solar forecasts)….vary greatly in their methods. They range from examining planetary orbits, to spectral analyses ….to artificial intelligence methods, to simply using general statistical techniques. Rather than concentrate on statistical…. methods, we discuss a class of methods which appears to have a “physical basis.” Not only does it have a physical basis, but this basis is rooted in both “basic” physics (dynamo theory), but also solar physics … “

    “My colleagues and I have …expanded the prediction methods using “solar dynamo precursor” methods, …These methods are now based upon an understanding of the Sun’s dynamo processes- to explain a connection between how the Sun’s fields are generated and how the Sun broadcasts its future activity levels to Earth. This has led to better monitoring of the Sun’s dynamo fields and is leading to more accurate prediction techniques. Related to the Sun’s polar and toroidal magnetic fields, we explain how these methods work, past predictions, the current cycle, and predictions of future of solar activity levels for the next few solar cycles.”

    “The surprising result of these long-range predictions is a rapid decline in solar activity, starting with cycle #24. If this trend continues, we may see the Sun heading towards a “Maunder” type of solar activity minimum – an extensive period of reduced levels of solar activity. “

    Comment by William Astley — 30 Nov 2007 @ 6:27 PM

  123. Rasmus,
    just a little reply.

    A) about the solar cycle. For “peak” I was intending the possible effect of the solar cycle length pattern on the TSI patter. To be more precise, the idea is that when the solar cycle length is small TSI is high, so the two things are neg-correlated. In your figure it is evident that during the 40s the solar cycle length was at a minimum, thus TSI (according this hyothesis) was at a maximum. I hope this helps.

    B) About ACRIM and PMOD: unfortunately, the story you know is quite confusing. It is not for arrogance but I have a direct knowledge of this issue because I regularly meet Willson of the ACRIM group and I have met Frolich and personally discussed with him and while he was discussing with Willson. My story is the correct one. PMOD alters the satellites data before 1980 and during the ACRIM gap. That is, they alter both ACRIM1 data and NIMBUS7 data. Willson says that Frolich has altered the ACRIM1 data without even contacting him and discussing the matter with him.

    During the ACRIM gap PMOD claims that they are using NIMBUS7 as you can see in their web-site, but indeed they are using an altered version of it to fit a proxy model.

    From 1978 to 1980 both Nimbus/7 and ACRIM1 show a decrease, PMOD alters both in such a way to make to appear that the TSI is increasing during that period. During the ACRIM gap (1988-1991) Nimbus7 shows an increase, PMOD alters it in such a way to obtain a decrease during the same period.

    This is a statement from Willson:
    **
    The PMOD composite was constructed to agree with the linear regression solar proxy model of Judith Lean and took considerable liberties with the satellite TSI database to accomplish it. Frohlich and lean modified the results of the Nimbus7/ERB and ACRIM1 experiments published by their science teams to agree better with Lean’s model. In the case of ACRIM1 this was in direct contradiction with the (published) satellite performance issues and observations and without any consultation with the science team.

    To construct a multi-decadal composite it is necessary to relate the ACRIM1 and ACRIM2 results across the two year gap between them. There are two choices to do this and they give quite different results. The highest quality ‘ACRIM gap’ comparative database is the Nimbus7/ERB which produces a TSI composite demonstrating significant upward trending during solar cycles 21 – 23, then a return to cycle 21 levels approaching cycle 24. The other ‘gap’ database, the ERBS/ERBE, clearly inferior to the Nimbus7/ERB in calibration, precision and sample rate, produces no significant TSI composite trend when used to bridge the ‘gap’.

    The difference between Nimbus7/ERB and ERBS/ERBE results during the ‘gap’ is caused by uncorrected degradation of the ERBS/ERBE sensors. Nevertheless Frohlich and Lean chose the ERBS/ERBE connection to relate the ACRIM experiments. The resulting PMOD composite shows no significant trend and agrees better with the predictions of Lean’s proxy model than if they had used the Nimbus7/ERB comparisons. This facilitates their conclusions about solar trending and climate change but does not represent the most objective use of the extant TSI satellite database.

    **

    Rasmus, note that PMOD uses ERBS/ERBE just to cross calibrate ACRIM1 and ACRIM2, not to fill the ACRIM gap, where they must use Nimbus7. The problem is that when ERBS/ERBE is used NIMBUS7 does not match with ACRIM1 and ACRIM2 anymore. Thus, PMOD has decided to solve the problem by altering NIMBUS7 data!

    Hoping that this helps you to update your story!

    To #115

    Charles, I believe you can find those data in internet, if not, email me. About the other solar reconstructions, according to the method I adopted in the paper they would give more or less the same result if you use the same temperature data. In fact I am assuming that the climate sensitivity to solar change is such that it fits the data during the preindustrial period. This means that if the trend in the TSI data is larger the sensitivity is smaller.

    Comment by nicola scafetta — 30 Nov 2007 @ 7:38 PM

  124. Re: #122 (William Astley)

    The prediction of Schatten & Tobiska to which you refer uses an entirely new prediction method which has never been tested. The track record of new prediction methods of solar activity is poor, to be generous. You say you found “a number of papers … that predict a Maunder type minimum.” There are vastly more papers which predict otherwise. For you to claim that we’re necessarily headed for another Maunder-like minimum (and it’s clear to everybody that’s your meaning) is nothing more than wishful thinking on your part.

    Your further statement that “The solar Maunder like minimums do appear to follow a 200 year cycle” is absolute rubbish. We’ve only seen one of them — two if you count the Dalton minimum as “Maunder-like” — and to conclude from this that they’re cyclic is the fantasy of an overactive imagination declaring as fact what you wish to be true. I have indeed studied the proxy data, which not only fail to support a genuine periodicity, they actually contradict it. As I said before, there may or may not be pseudoperiodic behavior on that time scale, but claims of genuine periodicity are contradicted by the available evidence.

    It’s seems that you simply won’t listen to reason on this matter.

    Comment by tamino — 30 Nov 2007 @ 8:32 PM

  125. William, have you looked at Solanki’s paper on sunspot maxima and minima whose link was kindly provided by Timo? It looks pretty good and has some comments on whether there is any real periodicity in solar magnetic activity. He also points out that the minima/maxima have an interesting distribution of durations and amplitudes. I reproduce the link here:
    http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf

    Comment by Ray Ladbury — 30 Nov 2007 @ 8:46 PM

  126. It’s “hold onto your parkas” time in Mid and Eastern Canada and the US midwest – the unfrozen, relatively warm patch of Arctic ocean seems to have encouraged a massive (larger than I’ve seen in 10+ years, anyway) influx of Pacific air, see here.

    If this plays out like it has in past years, this will act like a carooming billard ball, and knock a big cascade of polar air over those areas (the actual dynamics look a tad more complex; but its a good sound bite). Judging from the size of the “billard ball”, it’s going to be stronger (Eg. 2-3 times) than usual.

    Also see animated and this IR movie. It’s happened before, just not this strongly.

    Ken.

    Comment by Ken Rushton — 30 Nov 2007 @ 9:43 PM

  127. Tamino (121) wrote:

    I was under the impression that the chief reason for the asymmetry in glacial cycles (deglaciation faster than glaciation) is that the accumulation of ice sheets is necessarily slow (one snowflake at a time) while wasting of ice sheets can happen much faster, including both mechanically (big chunks break off) and and thermodynamically.

    Actually I believe we are both right — and thank you for the reminder.

    The build-up of icesheets is a slow process, but so is the clearing of carbon dioxide from the atmosphere. Each are slow feedbacks that quite literally take tens of millenia to fully react to decreased forcing. Carbon dioxide on the order of 100,000 years (roughly the length between ice ages), and according to a paper by Hansen, at least in the case of Greenland’s icesheet, if it goes, it will take 30,000 years to be reform.

    And they are slow feedbacks to increased forcing (solar insolation due to the orbit of the earth, an impulse of anthropogenic greenhouse gases, the release of methane, Siberian supervolcanoes, etc.) but considerably faster than they are in the other direction. The $64,000.00 question is:

    How much faster?

    Comment by Timothy Chase — 30 Nov 2007 @ 10:23 PM

  128. #125, This Jet stream was made after several North Pacific intense North Pole bound cyclones, surely influenced by the record thin ice Arctic Ocean. The air is of course warmer in a great chunk of the Arctic, especially over the thin ice.

    I am quite impressed with Rasmus patience, and also very pleased of Scaletta entering a debate. Although the acronyms used at times make it a difficult
    read.

    There is also an important point to make, when the majority of scientists say
    that solar activity has remained steady since 1950, the minority saying otherwise must show compelling data backing this up. Reading solar constant graphs, my favorite, SARR TSI since 1978, I can see what the majority are saying quite well

    http://science.nasa.gov/headlines/y2003/images/solcon/beat_lg.gif

    Direct reliable measurements show a remarkable cycle, when during the late 70′s the solar peaked while it was much cooler than recently. Same sun,
    but greater recent warming, someone needs to come up with a sensational explanation as to why Solar is responsible for 1998-2007 warming.

    Comment by wayne davidson — 1 Dec 2007 @ 12:19 AM

  129. Correction to 126

    I noticed there is a problem with what I said. The level of carbon dioxide will reach equilibrium only asymptotically. So after 100,000 years I believe you are talking about 5% being left. Slowest part of the process is mineralization.

    So where does this leave us? Well, the actual answer as to which drives the cycles would appear to be not so much a little of each, but… it depends…

    Ice-driven CO2 feedback on ice volume
    W. F. Ruddiman
    Clim. Past, 2, 43-55, 2006
    http://www.clim-past.net/2/43/2006/cp-2-43-2006.html

    … presumably. But prior to this paper at least, it was thought that ice took a back seat. Based on bubbles.

    Comment by Timothy Chase — 1 Dec 2007 @ 1:17 AM

  130. Re: William Astley (#122)

    The high resolution Be-10 records, e.g. the work of Jurg Beer and colleagues at Dye-3, show unequivocally that the solar magnetic cycle continued during the Maunder minimum.

    Even in the absense of visible sunspots, there is a very obvious 11-year cycle in Be-10 production. This implies that the solar magnetic field continued its pattern of reversals uninterrupted. The relatively high flux of Be-10 implies that the intensity of the solar field was significantly reduced, but it was certainly neither absent nor static.

    Also, I would like to again state my agreement with tamino. Proxy records show a pattern of solar behavior that is episodic, but not periodic. The apparent pattern of ~200 year cycles in major minimum is not a persistent long-term feature of the data and so should not be used to draw any sort of a strong conclusion about the future.

    Comment by Robert A. Rohde — 1 Dec 2007 @ 1:59 AM

  131. Re 125
    NEAT! However, looking at surface sea temps ( http://www.osdpd.noaa.gov/PSB/EPS/SST/contour.html ) and the brightness temperature of various levels of the atmosphere (http://pm-esip.msfc.nasa.gov/amsu/index.phtml?12 ) it is hard to believe that a patch of Arctic water could trigger the northward movement of so much warm, moist air. Perhaps other factors also contribute?

    Comment by Aaron Lewis — 1 Dec 2007 @ 3:33 AM

  132. #127
    Wayne : Same sun, but greater recent warming, someone needs to come up with a sensational explanation as to why Solar is responsible for 1998-2007 warming.

    For the moment, we need to explain the 1977-2001 warming. Because there’s no trend on surface or low troposphere for 2001-2007 (according to HadCru, RSS and UAH). (2001-2007 are of course warmer than 1996-1990 mean, 0,4 K approx., but nothing like a global acceleration of surface warming for these most recent years)

    Cycles 21 and 22 were very similar (unfortunately for solar researchers). It seems cycle 23 has been quite different and we may hope cycle 24 will be even more, so as to better observe and understand the physics of cyclic variations. The ideal situation (for the present debate) would be of course a very quiet cycle 24.

    Comment by Charles Muller — 1 Dec 2007 @ 7:26 AM

  133. rasmus, your:

    “This is probably because the relaxation time response has been increased between the two panels and is greater than 10 in the lower panel. The presence of a trend should not affect the amplitude of the higher frequency in such a simple linear system (see my reproduction above).”

    Spot on! It has been increased by two thirds from 10 to ~16.7

    I suspect this is a genuine mistake as if it had been left at 10 the secular trend reaches 80% of final value by t=50 as indicated in the text whereas the graph has it at only 70% leaving 30% of the warming to occur in the t > 50 period not 20% as stated.

    Even if a mistake it is misleading and … it is a mistake that had to wait for you to pick it up.

    Best Wishes

    Alexander Harvey

    Comment by Alexander Harvey — 1 Dec 2007 @ 11:43 AM

  134. Charles Muller (#131) wrote:

    For the moment, we need to explain the 1977-2001 warming. Because there’s no trend on surface or low troposphere for 2001-2007 (according to HadCru, RSS and UAH). (2001-2007 are of course warmer than 1996-1990 mean, 0,4 K approx., but nothing like a global acceleration of surface warming for these most recent years)

    I myself have three questions.

    First, why do you consider six years to constitute a trend? Typically, given the internal variability due to Southern Oscillation, the North Atlantic Oscillation and Pacific Decadal Oscillation, etc. a climatologist would require in the neighborhood of at least 15 years before they would consider it a trend.

    Second, would you consider the three years or so to constitute a trend? Looking at the temperature records for all these indicies, I see a “flat trend” of two or three years between 1980 and 1985. In fact, I see a cooling “trend” of perhaps a couple of years.

    Third, why do you dismiss the role of carbon dioxide that the vast majority of climatologists regard as being responsible for the trend from 1979-2001, or for that matter, the role of anthropogenic greenhouse gases from 1882 to the present day?

    Come to think of it, the last of these brings to mind a few more questions.

    Do you believe that it doesn’t absorb infrared radiation? Do you believe that it doesn’t emit backradiation? Do you believe that rising levels of carbon dioxide have no effect upon the atmosphere’s opacity to infrared radiation?

    Do you believe that climatologists are mistaken with respect to the distribution of carbon dioxide in the atmospheric column? Or do you believe that levels of carbon dioxide haven’t been rising throughout the 20th Century?

    Are what climatologists would normally regard as facts simply dismissed when you find them unpalatable?

    Comment by Timothy Chase — 1 Dec 2007 @ 11:54 AM

  135. #131, Charles, this apparent +0.4 K has made remarkable transformations in the Arctic. Temperature increase in the Northern Hemisphere’s polar region was much more stronger, not explained by very reliable solar measurements, nor by any oscillation which have occurred many times in the past without giving the same results. What was observed was a gradual consistent heat boost despite oscillations, especially the Arctic Oscillation. From reliable solar constant measurements
    we can clearly see that the sun had not contributed extra heat as measured on the ground and in the atmosphere, what is left can be explained by a change in atmospheric chemistry though. For the solar causation guys, the question to ask: where is the extra heat coming from between 1977-2007?

    Comment by wayne davidson — 1 Dec 2007 @ 1:14 PM

  136. Re solar periodicities in 123, it’s widely understood that the sun’s dynamics are accurately described by a dynamo. It’s well known that dynamos typically exhibit nonlinear “chaotic” oscillations, as well as quasi-periodic oscillations. Whether the sun’s dynamics are currently in a quasi-periodic or chaotic regime is debatable, but for my money, I’d bet on chaotic oscillations.

    Comment by Jim Galasyn — 1 Dec 2007 @ 1:55 PM

  137. rasmus> Not much scientific reasoning there. No documentation no proof. Just childish statements taken out of the air. ClimateAudit publishes statements such as ‘[people at] RealClimate are not scientists at all. They are priests of a mystery cult.’.

    I did a search to find the statement that you quote. It appears to be from an ordinary commenter, not someone affiliated with the site.

    Would you want RC to be judged by the worst comments that you let through?

    [Response: Yes. Moderation of comment threads to remove namecalling and innuendo is part of what keeps serious conversation going. Similar comments here have been, and will continue to be, rejected. - gavin]

    Comment by Steve Reynolds — 1 Dec 2007 @ 3:22 PM

  138. Timothy

    First, why do you consider six years to constitute a trend? Typically, given the internal variability due to Southern Oscillation, the North Atlantic Oscillation and Pacific Decadal Oscillation, etc. a climatologist would require in the neighborhood of at least 15 years before they would consider it a trend.

    Seven years rather than six, Hadley Center have announced 2007 would be the sixth warmest year, similar to 2006. I agree with you, 7 yrs does NOT constitute a significative trend (and 30 yrs is better than 15 yrs for that purpose). The same is true for many other domains (five years of GRACE measure on Greenland, for example, usually presented as an alarming trend in ice meting, but you will agree with me that such a short measure is not very significative)

    But here, I was answering to Wayne 127, that is correlation or anticorrelation between Ts and Fs for 1998-2007 (he chose this period). So, I just precised the absence of recent trend, after 2001. As cycle 23 was weaker than two previous one, recent years are not a good argument for an insensitivity to solar variations, rather the opposite.

    You’re right for intrinsic variability. I suspect the huge warming of 1977-2006 period to be in part due to such a variability, not very well constrained by models presently.

    A question for you : if there’s no more trend on surface temperature for 2001-2010, would you consider that as significant ? Or more precisely, how many years of Ts stagnation would be necessary to revise our evaluation of transient climate response to CO2 forcing ?

    Second, would you consider the three years or so to constitute a trend? Looking at the temperature records for all these indicies, I see a “flat trend” of two or three years between 1980 and 1985. In fact, I see a cooling “trend” of perhaps a couple of years.

    No, of course.

    Third, why do you dismiss the role of carbon dioxide that the vast majority of climatologists regard as being responsible for the trend from 1979-2001, or for that matter, the role of anthropogenic greenhouse gases from 1882 to the present day?

    The role of CO2 in warming, no, there’s no physical reason to dismiss it. But attribution-detection of this warming, yes. In fact, I don’t dismiss it, I simply consider there are still too much uncertainties in models (eg aerosol, clouds, etc.), too noisy signals in climatologies, too low level of understanding of different forcings (including solar one we discuss here) for giving a great confidence to AD exercise, so to CO2 role in surface trends. I’m quite sure modern GW is in part anthropic, but I wouldn’t bet on a 40, 60, 80%… responsability of GHGs forcing.

    Do you believe that it doesn’t absorb infrared radiation? Do you believe that it doesn’t emit backradiation? Do you believe that rising levels of carbon dioxide have no effect upon the atmosphere’s opacity to infrared radiation?

    No, no, no… :D We all know that CO2 forcing in itself have a weak effect on Ts, approx 1 K for 2xCO2 or 3,7 W/m2 (IPCC AR4 best estimates). The problem is not IR absorption-emission, rather correct evaluation of water vapor and clouds feedbacks to an IR forcing.

    As Lindzen, I observe that the present 85% of CO2 doubling gave a 0,76 K response in Ts ; but contrary to Lindzen, we should recall it’s a climate transient response, not an equilibirum state. But even for CTR, a 85% of 2xCO2 would give a 1,0 – 2,2 K Ts response in the 20 IPCC models (see table 8.2), so we’re still far from that (and far more if solar forcing play a non negligible role in the 0,76 K observed trend). Fortunately, we could always fill the gap with aerosols…

    Comment by Charles Muller — 1 Dec 2007 @ 3:41 PM

  139. The discussion with William Astley on heliomagnetic activity as a contributor to climate has brought up the ideas of periodicity and quasi-periodicity. At the risk of gross oversimplification, I’ll look at what we mean by these terms:
    Periodicity occurs for states that are stable ans oscillate about some equilibrium position. We don’t expect either the geodynamo or heliodynamo to be truly periodic, since they have 2 metastable states with roughly equal energies–the dipiles pointing to either pole. Because the dipole state are energetically favorable, it takes energy–a fluctuation of the energy in the heliodynamo–to push it out of one state. The fluctuations happen continually, but large fluctuations are rarer. Because the expected time between fluctuations of a given size has some expected value, the heliodynamo will exhibit a quasi-periodicity about this mean. Once the dipole decays, you get a period of instability with energy going into the higher multipoles until the system stabilizes back in one of the energetically favorable dipole states. The geodynamo behaves similarly, albeit with a much longer period due to the relatively slow circulation of the outer core liquid iron and the impedance provided by the solid inner core.
    So it is a mistake to expect one solar cycle to look like the last, or one “Magnetic Minimum” to behave similarly. We expect a distribution of magnitudes and “periodicities”. So I think Usoskin and Solanki are on the right track.

    Comment by Ray Ladbury — 1 Dec 2007 @ 4:13 PM

  140. gavin> Yes. Moderation of comment threads to remove namecalling and innuendo is part of what keeps serious conversation going. Similar comments here have been, and will continue to be, rejected.

    post 18> Odds are they’re being rewarded for their tireless contributions somehow, along with the editors of the crappy journals where their discharges are deposited.

    It looks to me like there is ‘namecalling and innuendo’ right here in this thread.

    raypierre even appears to continue the innuendo in his response.

    [Response: Thanks for bringing that to my attention. It's been edited. We don't catch everything, but feel free to email if you think comments have strayed. - gavin]

    Comment by Steve Reynolds — 1 Dec 2007 @ 4:22 PM

  141. Ain’t it funny how you have brilliant insights just as you hit the post button. An analogy that may help (and yes, it is an analogy only):
    We’re all familiar with the concept of a 100-year flood. The fact that such events occur ROUGHLY every 100 years does not cause anyone to suggest that weather is periodic. It is just that the conditions necessary for such an extreme event only come into being ROUGHLY every 100 years. Extreme events tend to follow a Poisson distribution and vary about the Poisson mean.

    This is one reason why having a physical understanding of the processes in your system is critical–it keeps you from making mistakes in characterizing its dynamical behavior.

    Comment by Ray Ladbury — 1 Dec 2007 @ 4:57 PM

  142. Charles Muller (#137) wrote:

    Seven years rather than six, Hadley Center have announced 2007 would be the sixth warmest year, similar to 2006.

    Well if you accept the short-term predictions of the Hadley Center, then I suppose you know what is in store for next year and the following decade. I on the otherhand wasn’t counting 2007 since we still have a month or so left.

    I agree with you, 7 yrs does NOT constitute a significative trend (and 30 yrs is better than 15 yrs for that purpose).

    Not for temperatures – given the oceanic oscillations.

    The same is true for many other domains (five years of GRACE measure on Greenland, for example, usually presented as an alarming trend in ice meting, but you will agree with me that such a short measure is not very significative)

    There I would have to disagree — unless you have reason to believe that the doubling of the rate of glacial water discharge or the tripling of glacial quakes in a decade is unrelated to the past decade being the warmest in well over a century’s time. I assume you believe that heat melts ice?

    But here, I was answering to Wayne 127, that is correlation or anticorrelation between Ts and Fs for 1998-2007 (he chose this period). So, I just precised the absence of recent trend, after 2001.

    By choosing so short a period, he was actually being generous.

    You’re right for intrinsic variability. I suspect the huge warming of 1977-2006 period to be in part due to such a variability, not very well constrained by models presently.

    Internal variability helps in the case of 1998 — a particularly strong El Nino in that year. But it would not seem to help with 2005 — which was a cool solar year. But in any case, Hadley seems to believe that they are getting a better handle on internal variability — now that they are specifically taking it into account.

    A question for you : if there’s no more trend on surface temperature for 2001-2010, would you consider that as significant ?

    I would consider the laws of physics more significant. Given the models, there might be a 5-10% chance of surface temperatures being flat for a decade. But I would have to give up Aristotle for Descartes to worry about the former.

    Or more precisely, how many years of Ts stagnation would be necessary to revise our evaluation of transient climate response to CO2 forcing?

    Well, if you are speaking of the transient climate response to CO2 forcing, I suppose about the same as an equal forcing due to solar insulation.

    The role of CO2 in warming, no, there’s no physical reason to dismiss it. But attribution-detection of this warming, yes. In fact, I don’t dismiss it, I simply consider there are still too much uncertainties in models (eg aerosol, clouds, etc.), too noisy signals in climatologies, too low level of understanding of different forcings (including solar one we discuss here) for giving a great confidence to AD exercise, so to CO2 role in surface trends. I’m quite sure modern GW is in part anthropic, but I wouldn’t bet on a 40, 60, 80%… responsability of GHGs forcing.

    Some forcings are more uncertain than others. The forcing due to greenhouse gases is well understood. The forcing due to solar insulation is well understood. Forcings due to aerosols and feedbacks due to clouds are less well understood — but our understanding is improving. So is our understanding of climate sensitivity to forcing.

    We all know that CO2 forcing in itself have a weak effect on Ts, approx 1 K for 2xCO2

    I believe that is 1.2 K. Which leaves perhaps 1.7 K to be explained in terms of feedback.

    … or 3,7 W/m2 (IPCC AR4 best estimates). The problem is not IR absorption-emission, rather correct evaluation of water vapor and clouds feedbacks to an IR forcing.

    This would seem to apply equally to solar insulation.

    As Lindzen, I observe that the present 85% of CO2 doubling gave a 0,76 K response in Ts ; but contrary to Lindzen, we should recall it’s a climate transient response, not an equilibirum state.

    Such honesty is genuinely appreciated.

    But even for CTR, a 85% of 2xCO2 would give a 1,0 – 2,2 K Ts response in the 20 IPCC models (see table 8.2), so we’re still far from that…

    We aren’t that close to a doubling of CO2 either. 378 ppm vs. 560.

    (and far more if solar forcing play a non negligible role in the 0,76 K observed trend).

    Forcing due to solar insulation has no effect upon our estimates of forcing due to CO2 — the latter is simply a matter of physics, not some sort of statistical residual.

    Fortunately, we could always fill the gap with aerosols…

    Not if they are flat, like solar insulation since 1950. But I believe we were discussing electron-scavenging solar winds and geomagnetic fields — and I do find Rube Goldberg devices amusing. :-)

    Comment by Timothy Chase — 1 Dec 2007 @ 5:24 PM

  143. Timothy #141

    The forcing due to solar insulation is well understood
    Precisely not. IPCC AR4 still attributes a “low level of scientific understanding” (even lower than aerosols).

    We aren’t that close to a doubling of CO2 either. 378 ppm vs. 560.
    The addition of anthropogenic forcing (in the IPCC AR4) 1750-present give a 3,17W/m2 forcing, so 85% of 3,7W/m2 (TOA).

    Forcing due to solar insulation has no effect upon our estimates of forcing due to CO2
    Of course. But I guess the problem lies with sensitivity rather than forcing. If there are indirect effects of solar forcing (because of UV spectral forcing and strato-tropo-ocean coupling, or because of GCR and nebulosity, or anything else), this would mean that AOGCMs uncorrectly simulate modern GW (or paleoclimates). And uncorrectly project for 2100. The more you attribute to solar factor for 1750-present warming, the less climate is supposed to be sensitive to GHGs factor (imagine, quite absurdly, that just 10% of the modern warming is due to GHGs ; it would be difficult to maintain an equilibrium sensitivity of 0,75 K/W/m2 for 2xCO2 ; the same is true, less absurdly, if GHGs account for 50% rather than 80% of modern warming).

    So in my opinion, if S&W are OK, it would imply that modern climate has not the same sentivity to 1 W/m2 TSI forcing and to 1 W/m2 CO2 forcing. Models presently conclude to the opposite. But if models do not correctly implement all the physical effects of total / spectral solar forcing, their conclusions are precisely not valid. We are stil far from that, because there is no decisive (physical) demonstration of indirect solar effects on climate.

    Comment by Charles Muller — 1 Dec 2007 @ 8:25 PM

  144. (#142 Precision in my previous post : the sum of positive anthropogenic forcing give 3,17W/m2. Of course, aerosols are supposed to mask the “real” transient response).

    Comment by Charles Muller — 1 Dec 2007 @ 9:05 PM

  145. Again, Charles, you are viewing climate like a Chinese restaurant menu, which, unfortunately, it is not. Forcing due to CO2 is one of the better understood aspects of the models. So if some other forcer pops its head up, it is unlikely CO2 forcing that would change in our understanding of climate, but rather some other, more uncertain forcing, such as aerosols, clouds, etc. This means that aerosols or other factors could be masking the full extent of CO2 forcing. The thing is that most other forcers actually act for relatively short times–aerosols for months, water vapor for days, CH4 for ~10 yrs. CO2 keeps on giving for thousands of years. During that period TSI will wax and wane. We will have periods of volcanism and quiescence. Forests will grow and die. Through it all, the CO2 we add will keep things just a wee bit warmer than they would otherwise be. That, of course presumes that the positive feedbacks do not kick things up a notch.
    If you manage to show the models are wrong, it is very likely that the new models show even more warming than the current batch. The uncertainties are skewed toward greater warming.

    Comment by Ray Ladbury — 1 Dec 2007 @ 9:27 PM

  146. In reply to Ray Ladbury’s comment:

    “William, have you looked at Solanki’s paper on sunspot maxima and minima whose link was kindly provided by Timo?… I reproduce the link here:”

    http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf

    Thanks Ray. This paper provides an overview of the solar maximum and minimum over the last 11,000 years. I have heard that the 20th century level of solar activity is the highest in 11,000 years. Usoskin, Solanki, and Kovaltsov’s paper puts that in perspective. (See figure 3 in the above linked paper.) This paper finds no repeated periodicity of “Maunder Minimums” except for the 2000 year cycle. (P.S. I support Tamino’s comment that solar periodicity can not be used to predict that cycle 24 will be a minimum.)

    Based on the Usoskin et al’s data and definition, in the last 11,000 years the sun has had 27 grand minimums which lasted from 20 to 160 years. The sun has spent 1880 years in grand minimum, 16.8% of the 11,000 year period.

    The sun in currently in a grand maximum, which Solanski’s defines as a smoothed sunspot number (see paper for details) greater than 50. According to the authors, the sun has had 19 great maximum in the 11,000 years and has spent 1000 years or 9% of the 11,000 year in grand maximum.

    In reply to Robert Rohde’s comment:

    “The high resolution Be-10 records, e.g. the work of Jurg Beer and colleagues at Dye-3, show unequivocally that the solar magnetic cycle continued during the Maunder minimum.”

    Yes. It will be interesting to see what is happening in a “Maunder Mininum”, if a cycle can be observed with modern instruments. I would expect there are minimums and deep minimums.

    In reply to Charles Muller:

    The following is a detailed explanation of Georgieva and Kirov’s, reasoning as to why to use the ak parameter as opposed to aa. The parameter ak, I believe measures significant change in the geomagnetic field which correlates with the solar wind strength. (i.e. The geomagnetic field is reacting to the solar wind.)

    http://arxiv.org/pdf/physics/0703187

    “Since the beginning of the 20th century, the correlation in the 11-year solar cycle between the sunspot number and geomagnetic aa-index has been decreasing, while the lag between the two has been increasing. We show how this can be used as a proxy for the Sun’s meridional circulation, and investigate the long-term changes in the meridional circulation and their role for solar activity and terrestrial climate.”

    Comment by William Astley — 1 Dec 2007 @ 10:32 PM

  147. I had written in 141:

    Some forcings are more uncertain than others. The forcing due to greenhouse gases is well understood. The forcing due to solar insulation is well understood. Forcings due to aerosols and feedbacks due to clouds are less well understood — but our understanding is improving. So is our understanding of climate sensitivity to forcing.

    In 142 Charles Muller responds:

    Precisely not. IPCC AR4 still attributes a “low level of scientific understanding” (even lower than aerosols).

    Judging from:

    FAQ 2.1, Figure 2. Summary of the principal components of the radiative forcing of climate change
    Chapter 2: Changes in Atmospheric Constituents and in Radiative Forcing
    Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, pg 136
    http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/AR4_WG1_ch02.pdf

    … it would appear that the range of uncertainty ascribed by the IPCC to forcing by solar insulation/irradiance relative to 1750 (or roughly the start of the industrial age) is actually smaller than that ascribed to any other factor — save stratospheric ozone and stratospheric water vapor. That is, unless you are thinking in terms of percentages. It is afterall a rather small forcing. Compared to other positive forcings, their estimate would seem to be just after stratospheric water vapor and black carbon on snow — the smallest of the positive forcings. And it would appear that tropospheric ozone plays a far greater role.

    *

    I had written in 141:

    Forcing due to solar insulation has no effect upon our estimates of forcing due to CO2 — the latter is simply a matter of physics, not some sort of statistical residual.

    In 142 Charles Muller responds:

    Of course. But I guess the problem lies with sensitivity rather than forcing. If there are indirect effects of solar forcing (because of UV spectral forcing and strato-tropo-ocean coupling, or because of GCR and nebulosity, or anything else), this would mean that AOGCMs uncorrectly simulate modern GW (or paleoclimates).

    You do like to throw a great many things together. Reminds me of a stew. Not much for clarity. However, given what I have just cited, “UV spectral forcing” wouldn’t seem to be the cause of much uncertainty.

    “strato-tropo-ocean” coupling? Now you seem to be tying yourself in knots. “GCR and nebulosity” ? Galactic Cosmic Rays?– not much of a trend there, I’m afraid. Nebulosity?– I believe you might have to clarify a bit here. “… or anything else” – nice escape clause. Sounds like the refuge of a radical skeptic: since we don’t know everything, we can’t claim to know anything. “… this would mean that AOGCMs uncorrectly simulate modern GW (or paleoclimates).” They seem to be doing rather well at simulating both, although there are still some details to work out.

    In any case, it helps to make distinctions — particularly when they involve different causal mechanisms. That is, assuming you prefer clarity over confusion.

    *

    In 142 Charles Muller states:

    The more you attribute to solar factor for 1750-present warming, the less climate is supposed to be sensitive to GHGs factor (imagine, quite absurdly, that just 10% of the modern warming is due to GHGs ; it would be difficult to maintain an equilibrium sensitivity of 0,75 K/W/m2 for 2xCO2 ; the same is true, less absurdly, if GHGs account for 50% rather than 80% of modern warming).

    And uncorrectly project for 2100. The more you attribute to solar factor for 1750-present warming, the less climate is supposed to be sensitive to GHGs factor (imagine, quite absurdly, that just 10% of the modern warming is due to GHGs ; it would be difficult to maintain an equilibrium sensitivity of 0,75 K/W/m2 for 2xCO2 ; the same is true, less absurdly, if GHGs account for 50% rather than 80% of modern warming).

    As I stated in 141:

    Forcing due to solar insulation has no effect upon our estimates of forcing due to CO2 — the latter is simply a matter of physics, not some sort of statistical residual.

    The forcing due to carbon dioxide and the forcing due to solar insulation are independently known. Comes down to physics. Up to this point at least you have agreed. Climate sensitivity to carbon dioxide? Given the past 460,000 years of paleoclimate records, I believe that is around 2.9 K per doubling.

    Of course if you have anything else of interest to you — at least regarding climatology — feel free to bring it up.

    Comment by Timothy Chase — 1 Dec 2007 @ 10:41 PM

  148. PS

    In my last post, I had written:

    The forcing due to carbon dioxide and the forcing due to solar insulation are independently known. Comes down to physics. Up to this point at least you have agreed.

    This included a link — to an anchor. Unfortunately the anchor was stripped out.

    But what I was linking to was where I had stated:

    Forcing due to solar insulation has no effect upon our estimates of forcing due to CO2 — the latter is simply a matter of physics, not some sort of statistical residual.

    … and Charles Muller had responded:

    Of course. But I guess the problem lies with sensitivity rather than forcing.

    It’s a pity: anchors would have been one more way to keep things in context.

    Comment by Timothy Chase — 1 Dec 2007 @ 11:21 PM

  149. Charles: “But if models do not correctly implement all the physical effects of total / spectral solar forcing” . Care to elaborate? Are TSI’s incomplete?

    Comment by wayne davidson — 1 Dec 2007 @ 11:31 PM

  150. William Astley (#145) wrote:

    In reply to Charles Muller:

    The following is a detailed explanation of Georgieva and Kirov’s, reasoning as to why to use the ak parameter as opposed to aa. The parameter ak, I believe measures significant change in the geomagnetic field which correlates with the solar wind strength. (i.e. The geomagnetic field is reacting to the solar wind.)

    http://arxiv.org/pdf/physics/0703187

    Good. Perhaps it will help me with an issue that I found earlier.

    Previously you (#105) wrote:

    This paper shows that the solar changes which modulate cloud cover correlate with the observed 20 th century temperature changes for the entire period in question.

    [Once again about global warming and solar activity
    K. Georgieva, C. Bianchi and B. Kirov, unpublished? not peer reviewed? - 2005]
    http://sait.oat.ts.astro.it/MSAIt760405/PDF/2005MmSAI..76..969G.pdf

    “We show that the index commonly used for quantifying long-term changes in solar activity, the sunspot number, accounts for only one part of solar activity and using this index leads to the underestimation of the role of solar activity in the global warming in the recent decades. A more suitable index is the geomagnetic activity which reflects all solar activity, and it is highly correlated to global temperature variations in the whole period for which we have data.”

    In Figure 6 the long-term variations in global temperature are compared to the long-term variations in geomagnetic activity as expressed by the ak-index (Nevanlinna and Kataja 2003). The correlation between the two quantities is 0.85 with p

    Rasmus responded inline in part: “Response: I’m a bit skeptical to the figures in that paper – how are the curves smoothed? (they remind me a bit of the work of Svensmark, Friis-Christensen & Lassen).”

    The smoothing is cause for concern, but I believe the following may be closer to the mark: “It’s also typical – when one index doesn’t work, a new one is thrown in.”

    I looked up the Ak index:

    Ak index. A daily index of geomagnetic activity for a specific station or network of stations (represented generically here by k) derived as the average of the eight 3-hourly ak indexes in a Universal Time day.

    Collection of Geomagnetic indices and like
    Väinö K. Lehtoranta 16.11.1997
    http://www.sci.fi/~fmbb/astro/indices.htm

    Is this what they mean by the Ak index?

    I haven’t had any luck finding anything else by this name associated with geomagnetic activity. But if so, what specific station or network of stations are they using? Given a large enough number of stations, one could easily select just those stations that would let you fit just about any curve you might wish — including the Dow Jones.

    But now looking at the paper you have just referenced:

    To extend the data record back by two more cycles, we use ak-index of geomagnetic activity, analogous to aa-index but derived from only one observatory (Helsinki) and highly correlated to aa-index in the period when the two overlap (Nevanlinna and Kataja, 1993). The mean annual values of ak are available online at (http://www.ava.fmi.fi/MAGN/K-index/ak-aa_index).

    The long-term changes in solar meridional circulation as the cause for the long-term changes in the correlation between solar and geomagnetic activity
    K.Georgieva and B.Kirov
    (unpublished? not peer reviewed? – 2006), pg. 7
    http://arxiv.org/ftp/physics/papers/0703/0703187.pdf

    Selecting one station is a better. Reduces the number of combinations. Helsinki might also make some sense in terms of their theory since it is farther north.

    But lets look at the description of the series itself:

    The files Hels_D_K1844-80_06 and Hels_H_K1844-97_05 contain geomagnetic activity indices derived from observations carried out in the Helsinki magnetic observatory. The first file is based on observations of the declination (D) from July 1, 1844 to June 30, 1880. The second file is based on the horizontal component (H) valid from July 1, 1844 to May 31, 1897. There are several gaps in the data series. Both files contain eight 3-hour K-values for each day and the daily activity index Ak. The first K-value in each row corresponds to the interval 0…3 in UT.

    http://www.ava.fmi.fi/MAGN/K-index/readme.html

    Still sounds like curve-fitting. At least two curves — with “several gaps.”

    PS

    Thank you for bringing us back (or at least closer) to the topic of the post.

    Comment by Timothy Chase — 2 Dec 2007 @ 5:47 AM

  151. #146, 147 Timothy (and #148 Wayne)

    Solar level of understanding : see AR4 IPPC, SPM, fig. 2, p. 4 (LOSU : low)

    Solar “small forcing” : that is precisely the problem. TSI forcing has been progressively reduced as we better calibrate it from satellite measurement and solar models. If we take the mean climate sensitivity of 0,75 K/W/m2, and apply it to solar forcing of AR4 (0,12 W/m2), it would imply a solar contribution to modern warming of max. 0,09 K, probably less (we’re not at the equilibrium). But in this case, I guess the first warming of 1910-40 is hard to attribute (See Stott 2003, Ingram 2006 for detection-attribution problems with solar forcing). So, the less TSI amplitude is pronounced on decennal or centennal reconstructions, the more you need some “solar amplification” mechanisms to match the data (that is, numerous climatologies correlated with solar variations in paleoclimates or in minimum-to-maximum cycle evolution). There are presently two fields of research for such amplification mechanisms : UV effect on stratosphere and coupling with troposphere, solar flux effect on GCR and nebulosity.

    Solar UV effect on stratosphere, and coupling with troposphere. As UV spectral variations are the most pronounced in total irradiance variations in a cycle (approx. 60%), researchers work on the influence of UV on stratosphere (chemical effect on ozone), its coupling with troposphere and general circulation (planteray waves, QBO, Brewer-Dobson circulation).
    See this special issue of Space Science Reviews 2006, recently published as a book by Springer, Section IV, particularly Geller 2006, Labitzke 2006, Chanin 2006, Calisesi et Matthes 2006, Salby et Callaghan 2006, Brönnnimann et al 2006, Haigh et Blackburn 2006 :
    http://www.springerlink.com/content/h70306173316/?p=3ffd16c15f8e45568f3b1decda1a0b45&pi=6
    Or for an introduction, the Haigh et al. Hadley Technical Note n°62, 2005, pp. 40-47.
    http://www.metoffice.gov.uk/research/hadleycentre/pubs/HCTN/index.html
    See also IPCC AR4, section 2.7.1.3

    GCR and nebulosity : the issue is still debated, see IPCC AR4 table 2.11, p. 202. The IPCC aggres that “some empirical evidence and some observations as well as microphysical models suggest link to clouds” but underscores a dependence on correlation and doublt/lack regarding physical mechanisms. On physical mechanisms, the CERN program CLOUD should give some results in the next few years. Anyway, IPCC attributes a very low LOSU. I’m still skeptic on a solar-GRC significative influence on nebulosity, but also skeptic on RC “dada” to dismiss systematically works on this field. I’m a layman, no reason to believe some specialits (Palle, Svensmark, Shaviv, Harrisson, etc.) are all wrong, some others (guys here) all right. So wait and see.

    Forcing, sensitivity : see the recent paper of Kiehl 2007: models all reproduce the T slope of past 100 yrs, but models differ by a factor 2-3 in CS. How is it possible ? Because they also differ by a factor 2 in forcings they implement (with aerosols as the most uncertain). Models with the highest CS are also models with the lowest forcing ; and vice-versa. So, it’s not hard to understand that if we reevaluate solar effects on climate – on Ts trend for past 100 years-, models with their present CS would be unable to reproduce the observed trend. Problem is not with TOA forcing itself, but with forcing effect on climate, that is sensitivity. And contrary to your assumption, there’s still a lot of uncertainty in water vapour / coulds feedbacks, which are by far the most important positive feedbacks in 2000-2100 simulations. See for example AR4 statement chap 8, p 592 : “Important deficiencies remain in the simulation of clouds and tropical precipitation (with their important regional and global impacts).” So, here again, wait and see.
    Kiehl :
    http://www.agu.org/pubs/crossref/2007/2007GL031383.shtml

    Comment by Charles Muller — 2 Dec 2007 @ 7:07 AM

  152. Charles Muller wrote: “So in my opinion, if S&W are OK, it would imply that modern climate has not the same sentivity to 1 W/m2 TSI forcing and to 1 W/m2 CO2 forcing.”
    Now, hold on a wee minute here. Let’s not abandon conservation of energy just yet. I realize that you may be sugesting that there could be feedbacks to insolation (note spelling) that are not present for ghg forcing, but this is a proposition for which we have zero evidence–in fact we may have evidence against it, since all feedbacks seem to be mainly thermally activated (albedo effects being the only quasi-exception, and even here higher temperature plays an important role).

    Comment by Ray Ladbury — 2 Dec 2007 @ 8:16 AM

  153. Here is a crucial section from one of the denialist pieces that are found only too frequently in our media.(Remember that New Zealand is home to an active group of denialists called the Climate Science Coalition, to whom the author of the following points is a “scientific advisor”).

    It is from Dr Chris de Freitas, School of Geography, Geology and Environmental Science, University of Auckland. It was published in the New Zealand Herald, 27 November 2007 and I quote only the points emphasised by the author:

    “There have been four periods of global warming in the last 1500 years.

    Data clearly shows the Earth cooled during a recent 35-year period despite the continuing rise of carbon dioxide in the atmosphere.

    In recent times, global temperature has been steady since 1998, despite the continuing rise of carbon dioxide in the atmosphere.

    Average global sea level rise has shown no acceleration over the past 300 years.

    And it is an uncontroversial fact that all climate models are unreliable, so their output is not evidence of anything. “

    As a non-scientists who has been closely following the issue of climate change, my response to those statements would be:

    What is the relevance/pertinence of the first point:?
    What 35 year period is being referred to in the second point?, which I do not accept as valid anyway.
    The third point is untrue (which is nicer than saying it is a lie).
    I don’t know enough to comment on the fourth point.
    The fifth point is a ridiculous over-simplification designed to confuse people who know nothing at all about science or about modelling.

    But I’m not a scientist, so could you help me out on this because I’d like to be able to do quick response answers to such denialist dross when it appears in our press.

    Comment by Paul Harris — 2 Dec 2007 @ 8:19 AM

  154. Re: #152 (Paul Harris)

    About “four periods of global warming in the past 1500 years”: what’s the evidence of this? What temperature reconstruction is relied upon for this statement? If you want to know more about temperature reconstructions, read this.

    About the “35-year cooling period”: I’ve discussed this before, there’s a period from about 1945 to 1975 when the planet was not warming. That’s not the same as cooling; genuine cooling seems to be limited to a very brief time span in the late 1940s. You can see a graph here. The cause of this mid-century non-warming is the large quantities of (man-made) aerosols in the atmosphere.

    About global temperature being steady since 1998: such statements represent either sloppy research or outright lies. See this.

    About global sea level over the last 300 years: What’s the evidence to support this claim? I hear a different story here.

    About computer models: In the most celebrated of all computer model predictions, 1988 James Hansen testified in congress about the future of global average temperature based on — you guessed it — computer models. His prediction turned out to be right. You can also read this paper about comparison of model predictions and subsequent observations.

    Comment by tamino — 2 Dec 2007 @ 10:13 AM

  155. Minor Quibble re #140- “In Statistical Methods in Hydrology”,U.S. Army Corps of Engineers -1962, by Leo R. Beard, he uses a binomial distribution to solve several probability situations involving the recurrence interval of specified floods.

    Comment by Lawrence Brown — 2 Dec 2007 @ 11:05 AM

  156. Re 154, Technically, I think that the Poisson distribution is the better to use, since we are talking about extreme events whose occurence fluctuates about a mean rate. That means the probability of occurrence in a given period (or trial for the binomial distribution) is small–precisely the conditions under which the binomial distribution reduces to the Poisson. So, while you can use either (the Binomial reducing to the Poisson for rare events), I think the Poisson distribution yields more insight.
    In either case, I don’t mean to impute that the physics of extreme weather and magnetodynamos have anyting in common.

    Comment by Ray Ladbury — 2 Dec 2007 @ 12:08 PM

  157. Ray Ladbury> Let’s not abandon conservation of energy just yet. I realize that you may be sugesting that there could be feedbacks to insolation (note spelling) that are not present for ghg forcing, but this is a proposition for which we have zero evidence…

    Shouldn’t we expect different feedback effects from insolation changes (stronger water vapor feedback in the tropics) than from GHG feedback effects (less effect in the tropics, more effect on polar albedo)?

    [Response: One might think this, but in fact the atmosphere turns out to be pretty good at redistributing heat, so that the pattern of temperature response to solar forcing and GHG (both normalized to have the same global mean) is quite similar. This shows up clearly in Caldeira's GRL article on geoengineering, but there are other studies that point in the same direction. That equalization also equalizes most of the things that might lead one to expect different feedbacks. --raypierre]

    Comment by Steve Reynolds — 2 Dec 2007 @ 12:17 PM

  158. Paul Harris, Tamino et al., One of the things people seem to get wrapped around the axle on is the whole idea of settled science in the face of model uncertainty. In modeling a complex system, it is common to start with the most important contributors and try to nail down their contribution, following with other contributors until we can actually say something about the physics. This, contributors such as TSI and forcing for the major ghgs. Eventually one reaches a state where the major contributors are constrained by several independent lines of evidence. They are unlikely to change, even though there may be considerable uncertainty among other factors. At this point the scienc regarding these factors/forcings can be considered “settled” even though uncertainty remains wrt the model as a whole.

    Comment by Ray Ladbury — 2 Dec 2007 @ 12:28 PM

  159. In reply to Timothy Chase’s comment 120.

    “Local abrupt climate change. Bipolar seasaw. Greenland suddenly warms (my comment cools.) by ten degrees Celsius or more within a matter of decades while Antarctica undergoes somewhat slower warming. Heinrich events. Can’t be explained by solar variability per se since it has effects which are in opposite directions in the two hemispheres. It would appear to be due to change in the modality of the ocean where ocean circulation flips between two modes.”

    The following is an attempt to explain what is observed using a solar forcing hypothesis that drives the events, supplemented with the Milankovitch orbital variations, albedo effect of an increase in the ice sheets, and so forth.

    A) Polar See-Saw
    The following is a link to Svensmark’s paper where he presents a hypothesis that modulation of cloud cover is the cause of the polar see-saw. His hypothesis is: As the albedo of the Antarctic ice, is greater than clouds, and as clouds provide insulation during the night, the net effect of an increased in cloud cover in the Antarctic is warming not cooling. Following that hypothesis an increase in cloud cover, causes other regions of the planet to cool, while the Antarctic warms and visa versa if there is a reduction in planetary cloud cover.

    http://arxiv.org/pdf/physics/0612145

    [Response: This is very poorly argued. The same effect is true in the Arctic (not mentioned by Svensmark), the data record is actually solely due to one station (Orcadas) in the early part and there is no evidence (none) that clouds in Antarctica have changed in any way - let alone in the way predicted by Svensmark's speculation. - gavin]

    B) Global Synchronous Cooling?
    The following is a new finding of synchronous global climatic change (Synchronous cooling, see links below), which if it is correct, seems to require a global climatic forcing function to explain the proxy data. This article notes researchers have found evidence of increased glaciation in the Andes which is concurrent with the North American glacial changes.

    The authors (Singer and Kaplan) of the study believe their data and analysis:

    “…address(es) a major debate in the scientific community, according to Singer and Kaplan, because they seem to undermine a widely held idea that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past.

    The implications of the new work, say the authors of the study, support a different hypothesis: that rapid cooling of the Earth’s atmosphere synchronized climate change around the globe during each of the last two glacial epochs. …”

    http://www.sciencedaily.com/releases/2004/03/040319071426.htm

    http://www.sciencedirect.com/science?_ob=GatewayURL&_method=citationSearch&_urlVersion=4&_origin=SDTOPTWOFIVE&_version=1&_piikey=S0033589404001644&md5=28f00741073e9a764288eab1487e626e

    Timothy, when I look at the 20th century warming and if it was followed by abrupt cooling, the hypothesized solar mechanisms (Electroscavenging and reduction in GCR followed by an increase in GCR and reduction in TSI) would seem to produce what is inferred to occur during a Heinrich event, during the glacial cycle. To me that hypothesized mechanism would seem to fit the observations.

    [Response: If you want a globally synchronising forcing, might I suggest... err... ummm..... well-mixed greenhouse gases? - gavin]

    Comment by William Astley — 2 Dec 2007 @ 12:29 PM

  160. Steve, keep in mind that forcing due to H20 will be logarithmic in humidity, so I think a watt is still a watt to first order. And in any case, you’re talking about spatial distribution of the power, not different forcers.

    Comment by Ray Ladbury — 2 Dec 2007 @ 12:50 PM

  161. Charles Muller (#150) wrote:

    Solar “small forcing” : that is precisely the problem. TSI forcing has been progressively reduced as we better calibrate it from satellite measurement and solar models. If we take the mean climate sensitivity of 0,75 K/W/m2, and apply it to solar forcing of AR4 (0,12 W/m2), it would imply a solar contribution to modern warming of max. 0,09 K, probably less (we’re not at the equilibrium). But in this case, I guess the first warming of 1910-40 is hard to attribute (See Stott 2003, Ingram 2006 for detection-attribution problems with solar forcing). So, the less TSI amplitude is pronounced on decennal or centennal reconstructions, the more you need some “solar amplification” mechanisms to match the data (that is, numerous climatologies correlated with solar variations in paleoclimates or in minimum-to-maximum cycle evolution).

    You are forgetting the fact that there are other greenhouse gases. Methane would be a big one. And while it increased rather dramatically in the earlier half of the century, it slowed in the latter half. And there are other forcings. Land use, ozone (a greenhouse gas), black carbon, reflective aerosols, etc..

    Stratospheric water vapor (a positive forcing) was revised upward. Total direct aerosol is entirely new (a negative forcing), direct carbon aerosol was revised upward (towards zero – a negative forcing), the actual sign on direct biomass burning aerosol changed (from a negative forcing to a positive forcing), direct mineral dust aerosol was revised upward (towards zero – a negative forcing), etc. All of this is available on in Chapter 2 of AR4 on page 204.

    More research has been done. Our understanding has improved. Our modeling of processes has improved. And we now have a better handle on a number of the forcings.

    Now of course the numbers which are given on page 204 show final forcings relative to 1750, not year for year, but if you don’t mind seeing the forcings expressed relative to 1880, the data used in the calculations by NASA GISS are available:

    http://data.giss.nasa.gov/modelforce/RadF.txt

    The graph that results from this data can be found on the following page:

    http://data.giss.nasa.gov/modelforce

    Charles Muller (#150) wrote:

    There are presently two fields of research for such amplification mechanisms : UV effect on stratosphere and coupling with troposphere, solar flux effect on GCR and nebulosity.

    Nebulosity — clouds. Why didn’t you use the term clouds? It could have meant aerosols, aerosols plus clouds, some fifth force — who knows? The term is — nebulous.

    UV. We take UV into account when we deal with ozone. Its a greenhouse gas. Operates primarily in the stratosphere. The coupling of the stratosphere with the troposphere? This too is taken into account by mainstream science.

    Galactic cosmic rays? They have been flat for as long as we’ve been measuring them. No trend. What would you expect? They come from supernova throughout the universe in all directions. Cosmic background noise that typically averages out — assuming you don’t have a supernova go off all that close to you.

    They are too small to form the nuclei that result in cloud formation. And we have more than enough nuclei of the right size to explain the formation of clouds.

    Charles Muller (#150) wrote:

    GCR and nebulosity : the issue is still debated, see IPCC AR4 table 2.11, p. 202. The IPCC aggres that “some empirical evidence and some observations as well as microphysical models suggest link to clouds” but underscores a dependence on correlation and doublt/lack regarding physical mechanisms.

    The “some empirical evidence” is a very small effect which is statistically significant — “detected” in Great Britain — but which does not show up in US data. What is still “debated” is whether there is any effect at all.

    Charles Muller (#150) wrote:

    On physical mechanisms, the CERN program CLOUD should give some results in the next few years. Anyway, IPCC attributes a very low LOSU. I’m still skeptic on a solar-GRC significative influence on nebulosity, but also skeptic on RC “dada” to dismiss systematically works on this field. I’m a layman, no reason to believe some specialits (Palle, Svensmark, Shaviv, Harrisson, etc.) are all wrong, some others (guys here) all right. So wait and see.

    You will notice that some of these authors are quite specifically proposing it as a mutually exclusive alternative to mainstream science. The geomagnetic field explains everything. There exists such-and-such a correlation. William Astley pointed us to just such a paper.

    But then what happens to our knowledge of spectra? Spectral absorption? Satellite imaging of infrared emissions by greenhouse gases? Ability to image altitude by the optical thickness of carbon dioxide? The strong super greenhouse effect detected in the tropics? The ability to image the emissions of all the major greenhouse gases at a variety of altitudes using over two thousand different channels? Things for which we have a great deal of data?

    Charles Muller (#150) wrote:

    Forcing, sensitivity : see the recent paper of Kiehl 2007: models all reproduce the T slope of past 100 yrs, but models differ by a factor 2-3 in CS. How is it possible ? Because they also differ by a factor 2 in forcings they implement (with aerosols as the most uncertain). Models with the highest CS are also models with the lowest forcing ; and vice-versa. So, it’s not hard to understand that if we reevaluate solar effects on climate – on Ts trend for past 100 years-, models with their present CS would be unable to reproduce the observed trend. Problem is not with TOA forcing itself, but with forcing effect on climate, that is sensitivity. And contrary to your assumption, there’s still a lot of uncertainty in water vapour / coulds feedbacks, which are by far the most important positive feedbacks in 2000-2100 simulations.

    Climate sensitivity?

    The best estimate has been around 3 K since the 1960s. 460,000 years of paleoclimate data says the same thing. The forcings? They give you the spreads. In some cases the forcings differ by as much as a factor of two, but generally these are small forcings.

    Water vapor and clouds? Wouldn’t affect the paleoclimate data — it already takes them into account. Many of the uncertainties tend to cancel out. Clouds have both an albedo effect and a greenhouse effect.

    And AR4 is generally several years out of date. It doesn’t take into account the most recent research, the fact that we have reduced many of the uncertainties. But where there are still problems with the modeling — its there in the mainstream literature. Jim Hansen is quite explicit about the deficiencies which still exist in the modeling by NASA GISS.

    Comment by Timothy Chase — 2 Dec 2007 @ 1:59 PM

  162. #159 Does this really happen?:

    “As the albedo of the Antarctic ice, is greater than clouds, and as clouds provide insulation during the night, the net effect of an increased in cloud cover in the Antarctic is warming not cooling.”

    Recent Arctic long nights had a more extraordinary effect, clear skies with way above average surface temperatures. Secondly and to complement this, the great ice melt of 2007 was done by a series of consecutive clear air Anticyclones. Clouds were not involved. GCR’s during a solar minima should be greater , by theory, more clouds….

    #150 Thanks for the elaboration Charles, UV correlates well with the stratosphere, which has been
    colder than warmer lately (past ten years), this has not affected the warming troposphere, or if it has this means that the 1977-2007 troposphere (along with a theoretical normal temperature stratosphere) should have been even warmer then present all time maximas. But you must consider TSI and UV anomalies were almost the same, which brings me back to my original argument, where’s the extra heat coming from? I leave out GHG’s (the greatest and now the only reason for warming), and let you find a suitable likely substitute, if there is one.

    Comment by wayne davidson — 2 Dec 2007 @ 4:36 PM

  163. I responded Rasmus
    look at #123 above

    (I believe my reply was posted on this web site 2 days after I wrote it!

    I could see it with the computer I wrote it, but not for another computer.

    I do not know why.)

    Comment by nicola scafetta — 2 Dec 2007 @ 5:49 PM

  164. Thanks for the helpful replies to my earlier post.

    Comment by Paul Harris — 2 Dec 2007 @ 6:25 PM

  165. William Astley (#159) wrote:

    In reply to Timothy Chase’s comment 120.

    The following is an attempt to explain what is observed using a solar forcing hypothesis that drives the events, supplemented with the Milankovitch orbital variations, albedo effect of an increase in the ice sheets, and so forth.

    A) Polar See-Saw
    The following is a link to Svensmark’s paper where he presents a hypothesis that modulation of cloud cover is the cause of the polar see-saw. His hypothesis is: As the albedo of the Antarctic ice, is greater than clouds, and as clouds provide insulation during the night, the net effect of an increased in cloud cover in the Antarctic is warming not cooling. Following that hypothesis an increase in cloud cover, causes other regions of the planet to cool, while the Antarctic warms and visa versa if there is a reduction in planetary cloud cover.

    As others note, clouds would have a lower albedo in the northern hemisphere just as well as the southern. In the Arctic, Greenland and elsewhere.

    Likewise, a hypothesis without so much as the suggestion of a means of testing it constitutes mere opinion. When it is used to rescue a theory without a means of independent verification, it is called an “ad hoc hypothesis.”

    William Astley (#159) wrote:

    B) Global Synchronous Cooling?
    The following is a new finding of synchronous global climatic change (Synchronous cooling, see links below), which if it is correct, seems to require a global climatic forcing function to explain the proxy data. This article notes researchers have found evidence of increased glaciation in the Andes which is concurrent with the North American glacial changes.

    What sort of quality controls were in place? Were others able to replicate their findings? And as Gavin notes, it is based upon just one location. I noticed the same thing myself.

    Likewise, it would constitute only one thread-bare line of evidence even if it included a fair number of sites. It might easily be subject to a completely different interpretation — once other evidence comes in.

    Earlier Ray Ladbury (#50) states:

    OK, let us say the oceans do wind up being more important (there’s no evidence supporting this, but assume it anyway). Does that mean that we will reduce CO2 sensitivity? No, because it is constrained by many independent lines of evidence.

    This is a very important principle underlying empirical science. A conclusion which receives justification from multiple lines of evidence is generally justified to a far greater degree than it would be if it were to receive from only one line of evidence in isolation from the rest.

    With the IPCC, we had roughly 2,500 scientists in relevant fields contributing. It would not be unusual for a given author to write several dozen papers in a single year. Typically a paper will reference several dozen other papers. A single chapter in AR4 referenced more than 200 papers. Not that unusual for a review nowadays.

    William Astley (#159) wrote:

    The authors (Singer and Kaplan) of the study believe their data and analysis:

    “…address(es) a major debate in the scientific community, according to Singer and Kaplan, because they seem to undermine a widely held idea that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past….

    If it undermines a widely held idea (“… that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past…”) then it would appear that there is no “major debate in the scientific community.” Echoes of the creationist “teach the controversy” when there is no actual controversy in the scientific community.

    William Astley (#159) wrote:

    “… The implications of the new work, say the authors of the study, support a different hypothesis: that rapid cooling of the Earth’s atmosphere synchronized climate change around the globe during each of the last two glacial epochs. …”

    Rapid cooling of the Earth’s atmosphere synchronized around the globe isn’t what we see in the paleoclimate record. Rapid cooling occurs only with bipolarity. The cooling of a global ice age is gradual.

    As for the link — science by press release. It appears 4 months before the journal receives the article and nearly two years before online publication.

    William Astley (#159) wrote:

    Timothy, when I look at the 20th century warming and if it was followed by abrupt cooling, the hypothesized solar mechanisms (Electroscavenging and reduction in GCR followed by an increase in GCR and reduction in TSI) would seem to produce what is inferred to occur during a Heinrich event, during the glacial cycle. To me that hypothesized mechanism would seem to fit the observations.

    If 20th century warming were followed by abrupt cooling, the cooling would not fit the pattern of Heinrich Events. All of the Heinrich events occured during glacial periods. Currently we are in an interglacial. As such, it does not fit observations. Likewise, if we were to suddenly see 20th century warming followed by abrupt cooling, this would not fit the description of a Heinrich event. Heinrich events are usually preceded by Dansgaard-Oescher events, not the reverse. During one of these events Greenland warms typically by 5 C in 30-40 years.

    Nothing like this has occured in the Holocene Era. The warming that we have seen in the 20th Century doesn’t compare to this. But what we are seeing are quite possibly the highest temperatures in over a million years, perhaps longer. And the temperature is still rising.

    *

    Here are a few final thoughts…

    Let us assume that somehow it was demonstrated that a cosmogenic theory similiar to the one the authors you’ve cited proposed turned out to be right. How would you explain why carbon dioxide does not have the effect that mainstream science holds it does?

    We have HiTran — a database with data on over a million spectral lines for carbon dioxide and other molecules — obtained by precise measurements in labs. These spectral lines are virtually derivable from the first principles of quantum mechanics. We know that such gases do not simply absorb but emit the energy they receive. We can measure their emissions at ground level, from balloons, planes and by satellite. And in the case of the latter, they are taking measurements on approximately 2,500 different channels in the spectrum. Satellite images actually show carbon dioxide as it is drifting away from industrial centers.

    Here are links to some of this:

    Products – AIRS Carbon Dioxide
    NASA AIRS Mid-Tropospheric (8km) Carbon Dioxide
    http://www-airs.jpl.nasa.gov/Products/CarbonDioxide/

    Multimedia Animations
    http://airs.jpl.nasa.gov/Multimedia/Animations/

    Visualization of the global distribution of greenhouse gases using satellite measurements, by Michael Buchwitz. The Encyclopedia of Earth. Posted July 31, 2007
    http://www.eoearth.org/article/Visualization_of_the_global_distribution_of_greenhouse_gases_using_satellite_measurements

    For more check out comment 555 to the Part II: What Ångström didn’t know post.

    *

    Likewise, we can measure the backradiation that we recieve from the atmosphere. We can measure altitude by means of the opacity of carbon dioxide to thermal radiation between that altitude and the surface. We can measure the drop in temperature of the stratosphere as carbon dioxide and water vapor reduce the amount of thermal radiation which reaches it. And we have paleoclimate evidence demonstrating the strong feedback relationship which exists between temperature and carbon dioxide levels.

    *

    What is your explanation for the paleoclimate evidence? How do you explain the cooling of the stratosphere? The ability to measure altitude by means of optical thickness? What is your alternate explanation for our spectral measurements? And where is your alternate theory for quantum mechanics?

    Comment by Timothy Chase — 2 Dec 2007 @ 8:50 PM

  166. In reply to Gavin’s comment (to my comment 159) concerning A) Svensmark’s paper on the polar see-saw:

    “The same effect is true in the Arctic (not mentioned by Svensmark), the data record is actually solely due to one station (Orcadas) in the early part and there is no evidence (none) that clouds in Antarctica have changed in any way – let alone in the way predicted by Svensmark’s speculation.”

    Svensmark’s paper does include satellite data that supports modulation of Antarctic cloud and I have a paper that shows Antarctic cloud cover is modulate by Forbush events. I thought the Antarctic climate was isolated, where as the Arctic climate is not.

    Gavin is an expert in the completing polar see-saw hypothesis which is that ocean currents are hypothesized to cause the polar see-saw. The Arctic and Antarctic ice core temperature data that Svensmark provides in his paper shows a cyclic polar see-saw, which would be consistent with a solar forcing function.

    The Antarctic and Arctic temperatures are varying 180 degrees out of phase throughout the period measured by the bore hole temperatures.

    Gavin are you saving that Svensmark’s bore hole temperatures for that period are not correct or that ocean currents are responsible for the proxy data?

    In reply to Gavin’s second comment:

    [Response: If you want a globally synchronising forcing, might I suggest… err… ummm….. well-mixed greenhouse gases? - gavin]

    Yes GWG is a global forcing function. Is the question: What is correct factor for GWG forcing as compared to solar forcing?

    The second comment is in response to B) Kaplan and Singer’s finding of synchronous global cooling (see my comment 159) which can not be explained by the Milankovitch orbital variations as they are 180 degrees out of phase comparing Northern Hemisphere to Southern Hemisphere.

    There is evidence that a solar forcing function affects climate and there is evidence of cyclic solar change. (See below for an example.) In this case GWG has not response for the change. It seems unlikely GWG could not be responsible for the abrupt climate changes.

    “Solar modulation of Little Ice Age climate in the tropical Andes”

    http://www.pnas.org/cgi/reprint/0603118103v1

    “The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between
    anno Domini (A.D.) 1250 and 1810, coincident with solar activity minima. Temperature declines of approx 3.2 +/- 1.4°C and precipitation increases of approx. 20% are required to produce the observed glacial responses.”

    [Response: A polar see-saw does not provide evidence of GCR-cloud interactions. Since clouds are a net positive forcing in the Arctic as well as the Antarctic, Svensmark's theory would anticipate synchronous behaviour at the poles - not a see saw. That kind of behaviour is much more characteristic of ocean circulation changes. - gavin]

    Comment by William Astley — 2 Dec 2007 @ 10:59 PM

  167. > I could see it with the computer I wrote it, but not
    > for another computer.

    I noted this a while back; I still have to refresh pages here fairly often to see the most recent postings; for one example when using the “Recent Comments” links, the page will open to a copy of that thread that’s some hours outdated — without the recent comment whose link I clicked on showing — but refreshing the page will show it and often several other comments. It may be that copies are being cached on the local computer and not updated. Just guessing.

    Comment by Hank Roberts — 2 Dec 2007 @ 11:40 PM

  168. Re # 59 (62) Dear Ray:

    Ilya Usoskin responded to yr considerations as follows:

    “Dr. Ladbury is right. No statistically significant conclusion can be drawn concerning the shape of the distribution of the Grand Minima shape. But the matter is that the division on Maunder-like and Spoerer-like minima has been done much earlier basing on only a few minima. Our present result is consistent with such a division, although a long-tail continuous distribution cannot be excluded. I also agree that hardly any direct implication for climate studies is apparent, and we were primarily interested in observational constraints for solar dynamo models.”

    DEAR ALL:

    When you are here dealing with CGR, too, please see the following new study by Ilya Usoskin, of which Ilya sent the following comment:

    “….in our recent review we found an interesting relation (see Fig.4 and discussion in sect. 3.3).

    Best regards,
    Ilya”

    The study is:

    Usoskin, Ilya G., and Gennady A. Kovaltsov, 2007. Cosmic rays and climate of the Earth: possible connection. Comptes Rendus Geoscience, accepted October 30, 2007, in press, online http://cc.oulu.fi/~usoskin/personal/CRAS2A_2712.pdf

    Abstract

    “Despite much evidence relating climatic changes on Earth to solar variability, a physical mechanism responsible for this is still poorly known. A possible link connecting solar activity and climate variations is related to cosmic rays and the physical-chemical changes they produce in the atmosphere. Here we review experimental evidence and theoretical grounds for this relation. The cosmic ray – climate link seems to be a plausible climate driver which effectively operates on different time scales, but its exact mechanism and relative importance still remain open questions.”

    Comment by Timo Hämeranta — 3 Dec 2007 @ 7:53 AM

  169. Re 123, Nicola
    a few questions:
    What do you think about the composite of Dewitte et al. 2005 (IRMB)?

    The difference between PMOD and ACRIM before 1980 causes a more positive trend in the PMOD composite and thus does not explain the difference between the two trends, does it?

    According to your theory about solar cycle length, TSI during solar cycle 23 should be lower than during solar cycle 22 and 21, because solar cycle 23 is longer. Same thing for the length between the sunspot maxima (cycle 22-23 is considerably longer than cycle 21-22), TSI for 22-23 should be lower than for 21-22. Both contradicts the ACRIM composite but is in accordance with the PMOD. What’s your explanation?

    Comment by Urs Neu — 3 Dec 2007 @ 8:35 AM

  170. Re # 158 Ray

    Yr consideration reminded me what I wrote in 2003:

    “In Natural Sciences, new ideas, hypothesis, theories, observations, studies, experiments, results, and conclusions replace old ones.

    Although Climatology is a very young branch that has been widely studied for only about 20 years, this progress can be seen clearly. The progress is so swift – thanks to immense research funding – that many findings only two years old are outdated.

    Another aspect is the huge advancements achieved, and the following fragmentation of research into more and more detailed and specific areas.

    The progress and advancements make difficulty in mastering all the enormous amount of information. In “the good old days” one qualified scientist could master his/her branch. Not any more, and especially not in Climatology, a branch including so many sub- and adjoining branches.

    Climatology contains all the branches of Science which have to do with climate and weather and the tools to master those; e.g. meteorology, geology, oceanography, and cryosphere, lithosphere and biosphere studies, ecology, biology, chemistry, physics, astrophysics, solar, planetary and galactic cosmic ray studies, history, mathematics, statistics, etc., etc., etc..

    No one person can master all these subjects, and the adopted solution is co-operation.

    This co-operation has three forms:
    - a multiscientific approach: climatology is studied simultaneously by different branches, but the actual co-operation and especially integration remains feeble,

    - an interscientific approach: this integration is most effective when research ideas, methods and views of various branches are utilised in a planned co-operative process.

    - a cross-scientific approach: this provides an abstract conformity and finally a common theory for Climate.

    It seems to me that Climatology has become a combination of multiscience and interscience. And it is certain that we have not yet achieved an all-inclusive theory of climate.”

    Well, as far as I can see, this is the case also in foreseeable future.

    But, honest scientists do admit they don’t even try to find the ‘Truth’ whatever it may be, they only try to find probabilities.

    Comment by Timo Hämeranta — 3 Dec 2007 @ 8:40 AM

  171. Timothy #161
    I leave some aspects of our discussion OT here. Just some precisions.

    nebulosity : sorry, it’s a gallicanism, we say nébulosité in French rather than cloud or cloud-cover (nuage, couverture nuageuse).

    AR4 is generally several years out of date : not really true, it would be foolish to imagine there’ve been a mass of ground-breaking research or observations in 2006-2007. Climate is a slow process… as well as climate sciences.

    More broadly, you repeat that GHGs is a very well known forcing. But I agree with that. You suggest in fine that climate sensitivity is a well constained domain: I strongly disagree with that – and I think there’s a consensus among scientists for recognizing WV and cloud feedbacks are still a major source of uncertainty for climate projections.

    You tell me that coupling of stratosphere and troposphere is well taken into account. Do you have any reference ? AFAIK, the SPARC (Stratospheric Processes And their Role in Climate) project, from WCRP is still going on. We don’t know precisely the role of dynamical and radiative coupling with the stratosphere in determining long-term trends in tropospheric climate, or even the exact way by which the stratosphere and troposphere act as a coupled system. So, it would be very surprising the current generation of GCMs implements mechanisms whose physical understanding is still low. But maybe I’m out-of-date like a vulgar IPCC report, so references are wellcome (I mean precise references on the coupling strato-tropo and long term effects of that coupling in models).

    Comment by Charles Muller — 3 Dec 2007 @ 10:31 AM

  172. Hi Timo, Thanks for the info from Usoskin. Also, again, I think his conservative wrt GCR/solar-cycle modulation is warranted. Certainly, it is plausible that GCR could have some effect. It is not plausible that it can explain the current warming trends, and in the absence of a physical mechanism, it is impossible to even guess how important such modulation might be. What is clear is that it is extremely unlikely to revolutionize our understanding of climate sufficiently to dislodge anthropogenic CO2 as the most plausible mechanism for the current warming, since CO2 forcing is constrained by multiple lines of evidence to its current range of values.
    WRT, your post #170, with respect, I’d take issue with several of your contentions:
    1)Climate science has been studied for >150 years, and climate modeling dates back to at least early in the last Century. To contend that the science is too young to be well established is simply incorrect. As I posted previously, there are uncertainties, but there are many aspects that it is fair to say we know–ghg forcing among them.
    2)I also disagree that science has progressed to the point where no one can have a broad knowledge of it. I used to write for a physics trade magazine, and I found that in many fields, the same names kept recurring, regardless of whether the article–in geophysics for instance–was on deep-focus earthquakes, mantle hotspots or the geodynamo. John A. Wheeler (U of TX) is another example in physics–he’s said to be the guy Nobel Laureates turned to when they couldn’t solve a problem. It is true that such individuals are rare and that most of us find ourselves sucked into specialized fields of research. Still, they’re out there if you look, and while they may not be household names, their scope and judgement make them quite influential in science. And there are many of us in the rank and file of science who work hard to keep abreast of progress in a variety of fields. My day job is radiation effects in semiconductors. Yet I keep abreast of developments in geophysics, condensed matter physics, particle physics (my PhD subject), astrophysics and a variety of other subfields. As avocations I study history and philosophy of science, especially as they relate to prababilistic understanding.
    3)It is a mistake to downplay the level of cooperation in climate science. These guys attend the same meetings, read many of the same journals and often attended the same schools, and good research is likely to spread via word of mouth. The fact that not every subfield is integrated reflects the complexity of the subject and the likely significance of the various subfields for the current goals of climate theory more than it does any balkanization of climate science.
    4) Don’t downplay probabilistic and statistical argument. If properly executed, they provide us with the most reliable forms of knowledge. There is an old saw about a man with one watch always knowing what time it is and a man with two never being sure. However, a man with an ensemble of watches can not only hone in on the most probable estimate of the time, but also tell you how far he is off!

    Comment by Ray Ladbury — 3 Dec 2007 @ 10:39 AM

  173. #150 Wayne
    But you must consider TSI and UV anomalies were almost the same, which brings me back to my original argument, where’s the extra heat coming from? I leave out GHG’s (the greatest and now the only reason for warming), and let you find a suitable likely substitute, if there is one.

    In fact, TSI and UV anomalies are not the same, either in cyclic amplitude (UV change accounts for 60% of total change in a cycle, athough 8% of the radiation is emitted at these wavelenghts) or in effects on our atmosphere (UV mainly interacts with O2 and O3). And you know that’s still poorly observed – there’s for example a gap in XUV/EUV range for 1980-97 period, even if MUV and FUV have a reasonably well coverage.

    When you say “extra-heat”, I suppose you mean for 1977-2006 period – a 0,5 K warming in 30 yrs. Extra-heat from this period may come from GHGs, of course, but also mutlidecadal intrinsic variability, downward trend for aerosols in Northern Hemisphere except part of Asia, and… solar forcing we’re discussing. I focus on the later.

    First, according to te recent post of N. Scafetta quoting Willson, there’s still a strong disagreement between ACRIM and PMOD so we cannot exclude ACRIM team is right (which would imply a slight upward trend for TSI in cycle 21-23)

    Second, there’s still no conclusive argument in our debate for the timing of climate sensitivity to solar forcing. Even if you have no trend for recent cycles 21-23, it’s obvious for all TSI reconstructions show that solar activity is higher in 1951-2000 than in 1901-1950. Look at theses reconstructions : solar cycles minima of the second half-century appears as more active than solar cycles maxima of the first. So, more solar energy have penetrated climate system in the recent decades.

    Third, if we just take into account the TSI itself, variations for 1951-2000, 1901-1000 or 1750-2000 are very weak according to Wang-Lean, Solanki-Krivova or Forster reconstructions – for the longest period, less than 5% of total positive anthropogenic forcing. You may conclude that anthropic factors caused 95% of the observed warming for 1750-2000. But Gavin in a comment above (#34) suggests that solar forcing accounts for “roughly 10%-20% of 20th Century warming”. Even in this conservative estimate, how a forcing accounting for 5% of TOA budget translates in a 10-20% warming trend on Ts ? I guess we should precise the famous “solar amplification mechanism(s)” in terrestrial climate. When we’ll get the right physical explanations, we will ensure more precisley its importance by implementing it in models.

    I’m a layman, not a scientist. At this point, it would be nice if Rasmus, or Gavin or any RC contributor answers to this basic and direct question here : do you think there’s a solar amplification mechanism (even weak) in climate system, not fully understood now, or do you think on the contrary that models and observations reasonably exclude any mechanism of that sort, so that solar influence is strictly limited to TSI change in TOA budget?

    [Response: In terms of effects that have been demonstrated to exist in obs and models, only the change of UV impact on ozone (both strat and trop) has been shown to be relevant. So yes, there is at least one factor that amplifies some responses (regional patterns mainly rather than global mean temperatures), but that neither implies nor precludes other factors. They simply have not been demonstrated to be relevant (as yet). - gavin]

    Comment by Charles Muller — 3 Dec 2007 @ 11:27 AM

  174. Sorry if this is a bit off-topic, but some may find this interesting (or amusing, or frustrating).

    Test your knowledge of global warming:

    http://www.globalwarmingheartland.org/GWQuiz/Q1.html

    Comment by Chuck Booth — 3 Dec 2007 @ 12:38 PM

  175. William Astley (#166) wrote:

    Svensmark’s paper does include satellite data that supports modulation of Antarctic cloud and I have a paper that shows Antarctic cloud cover is modulate by Forbush events. I thought the Antarctic climate was isolated, where as the Arctic climate is not.

    Actually what Henrik Svensmark’s “The Antarctic climate anomaly and galactic cosmic rays” contains are graphs. The graphs which have a description speaking of ERBE refer you to “ref.” If you look up “ref.” in the references, there is nothing that corresponds to it or which mentions ERBE.

    As such, while there may be data for his graphs, he does not actually provide it or reference it in any recognizable fashion. Perhaps one of the “references” that his paper refers you to actually does contain the data — but there is no indication which of these references it might be.

    With regard to the paper you mention above but do not name — perhaps we can try forcusing on Svensmark for a bit first. There is only so much time in a day, and while I probably have considerably more time than Gavin, it is still limited.

    *

    What ERBE would seem to refer to is the Earth Radiation Balance Experiment. Basically ERBE is designed for a kind of accounting, measuring radiation coming in and going out in both the shortwave and longwave. The data it provides would be essentially of the same nature as that which forms the basis for the images I linked to in 165 — and which show that when you increase the amount of carbon dioxide or other greenhouse gases, you reduce the amount of thermal radiation which is leaving the system, increase the amount of thermal radiation which reaches the surface.

    Given the conservation of energy, the surface must heat up until it reaches a temperature at which it is emitting enough thermal radiation that it compensates for increased levels of greenhouse gases. This works for water vapor, carbon dioxide, nitrous oxide, CFCs and ozone — athough it is directly absorbing ultraviolet radiation from sunlight rather than relying upon the surface to convert sunlight into longwave. In terms of the principle, this will apply to all gases to the extent that they are able to absorb radiation in their environment. In any case, with ERBE he is relying upon the very same technology which demonstrates that the greenhouse effect must occur.

    *

    Oddly enough, if he is proposing this theory as some sort of alternative meant to explain bipolarity, it is not an alternative to an enhanced greenhouse effect, but an alternative to a bimodal theory of ocean circulation. Something which recieves no mention in his paper. As such, in contrasting his theory to the greenhouse effect, he is arguing against a strawman.

    *

    Now yes, of course the Antarctic climate is isolated — primarily by the Antarctic Circumpolar Current. When there was a land bridge between Antarctica and South America, Antarctica was subtropical. However, as the two continents moved apart, the circumpolar formed and became stronger, and given the location of the Antarctic continent, resulted in Antarctica being sent into a deep freeze. Mainstream science also relies upon this isolation to a degree to explain the behavior of Antarctica with current warming.

    *

    What his theory would at least seem to suggest in the context of global warming is “polar dampening.” Given the ice that exists at both poles, assuming that cloud-formation decreases with lower amounts of galactic cosmic rays, and relying upon a raising of albedo with lower amounts of clouds over Antarctica to result in lower temperatures per his bimodal theory, we would expect a reduction in clouds over the Arctic to result in cooling while the lower latitudes whereas the tropics will experience higher temperatures with diminished clouds.

    But what we are seeing with respect to the Arctic is polar amplification. We are likewise seeing strong polar amplification along the West Antarctic Peninsula.

    There is of course some cooling which is currently taking place in the interior of the Antactic continent, but there is much warming as well. The cooling itself would seem to be the result of the reduction ozone lowering the temperature of the stratosphere, resulting in an enhanced temperature differential between the troposphere and the stratosphere, strengthening the polar vortex. Air flow from the center of the continent has resulting in some cooling in other places.

    *

    Given polar amplification, the West Antarctic Peninsula has been warming quite considerably. In fact, the only place where we may currently be seeing more warming is over the Tibetan Plateau. The Larsen A Ice Shelf disintegrated in January of 1995 and the Larsen B Ice Shelf disintegrated in February of 2002. We have over a hundred glaciers which are picking up speed and heading to the ocean.

    Likewise the mass balance of Antarctica as a whole has begun declining – this was detected by Grace in 2006. Snow is adding to the ice mass of Antarctica (not surprising given that it receives so little precipitation, and warming temperatures will actually increase this precipitation), but this increased precipitation is more than outweighed by the melting which is occuring.

    And a large part of the continental interior of Antarctica experienced an unexpected melt only 310 miles from the South Pole back in 2005. Likewise, nearly all of the Southern Ocean has been warming — particularly along the coasts.

    And we are seeing rapid warming of much of the troposphere during the winter.

    Please see:

    Significant Warming of the Antarctic Winter Troposphere
    J. Turner, T. A. Lachlan-Cope, S. Colwell, G. J. Marshall, W. M. Connolley
    SCIENCE, 31 MARCH 2006, VOL 311, 1914-17

    … which is available at:

    Science – Significant Warming of the Antarctic Winter Troposphere
    Posted on: March 31, 2006 6:28 AM, by William M. Connolley
    http://scienceblogs.com/stoat/2006/03/science_significant_warming_of.php

    The exception which Svensmark believes “proves the rule” would seem not to be quite so much of an exception.

    *

    William Astley (#166) wrote:

    Gavin is an expert in the completing polar see-saw hypothesis which is that ocean currents are hypothesized to cause the polar see-saw. The Arctic and Antarctic ice core temperature data that Svensmark provides in his paper shows a cyclic polar see-saw, which would be consistent with a solar forcing function.

    The Antarctic and Arctic temperatures are varying 180 degrees out of phase throughout the period measured by the bore hole temperatures.

    Gavin are you saving that Svensmark’s bore hole temperatures for that period are not correct or that ocean currents are responsible for the proxy data?

    Actually Gavin is an expert in climate and paleoclimate modeling. He does not specifically focus on bimodal theories of ocean circulation. But I suppose there might be some utility in thinking that he does.

    *

    The bore hole temperatures of mainstream science is correct. What they describe are Heinrich events and Dansgaard-Oescher events. But this does not correspond to the warming which we have seen in the 20th century — it corresponds to what we saw more than 10,000 years ago during the ice ages.

    As I have stated earlier in 165:

    If 20th century warming were followed by abrupt cooling, the cooling would not fit the pattern of Heinrich Events. All of the Heinrich events occured during glacial periods. Currently we are in an interglacial. As such, it does not fit observations. Likewise, if we were to suddenly see 20th century warming followed by abrupt cooling, this would not fit the description of a Heinrich event. Heinrich events are usually preceded by Dansgaard-Oescher events, not the reverse. During one of these events Greenland warms typically by 5 C in 30-40 years.

    Nothing like this has occured in the Holocene Era. The warming that we have seen in the 20th Century doesn’t compare to this. But what we are seeing are quite possibly the highest temperatures in over a million years, perhaps longer. And the temperature is still rising.

    Likewise, simply in terms of the warming which is occuring in much of Antarctica which I mentioned above, the evidence is inconsistent with the Dansgaard-Oescher events in the most basic fact that as Greenland warms, we should expect to see Antarctica cool dramatically — instead of cooling in some places and rather dramatic warming in others.

    *

    William Astley (#166) wrote:

    Yes GWG is a global forcing function. Is the question: What is correct factor for GWG forcing as compared to solar forcing?

    By “correct factor for GWG forcing,” I assume you mean climate sensitivity to a forcing. Climate sensitivity isn’t built into the models. It is something which falls out of the models, although the exact value will depend upon the model. The models themselves are based upon primarly physics: radiation transfer theory, thermodynamics, fluid motion theory, etc.. But there is also a great deal of chemistry – particularly in the study of the atmosphere, ocean and carbon cycle — as well as some biology.

    *

    William Astley (#166) wrote:

    The second comment is in response to B) Kaplan and Singer’s finding of synchronous global cooling (see my comment 159) which can not be explained by the Milankovitch orbital variations as they are 180 degrees out of phase comparing Northern Hemisphere to Southern Hemisphere.

    You are thinking of the tilt of the axis which controls the seasons. What about the eccentricity of the orbit? This is what would control the amount of radiation the climate system receives in a year. The more eccentric the orbit, the faster the earth will be moving when it passes close to the sun and the more time it will spend at greater distances from the sun. Greater eccentricity will mean less radiation being received throughout the year. And changes in the eccentricity of the orbit are predictable — given the gravitational effects of Jupiter and Saturn upon the earth’s orbit.

    *

    William Astley (#166) wrote:

    There is evidence that a solar forcing function affects climate and there is evidence of cyclic solar change. (See below for an example.) In this case GWG has not response for the change. It seems unlikely GWG could not be responsible for the abrupt climate changes.

    There is considerable evidence of either quasi-periodic or chaotic solar change. We wouldn’t claim that greenhouse gases are responsible for initiating the warming that takes place as the result of changes in solar insolation. We would however claim that it is responsible for amplifying those effects — as rising temperatures will result in lowering the capacity of the oceans to absorb additional carbon dioxide and retain carbon dioxide the carbon dioxide which they have already absorbed, leading to increased levels of carbon dioxide, and falling temperatures will result in the reverse.

    Comment by Timothy Chase — 3 Dec 2007 @ 2:02 PM

  176. Re: #166 (William Astley)

    The second comment is in response to B) Kaplan and Singer’s finding of synchronous global cooling (see my comment 159) which can not be explained by the Milankovitch orbital variations as they are 180 degrees out of phase comparing Northern Hemisphere to Southern Hemisphere.

    The earth’s axial tilt (obliquity) affects both hemispheres equally, i.e., in phase, greater tilt causing more solar insolation at extreme latitudes (both north and south) but less in the tropics. The precession parameter, the product of eccentricity and the sine of the angle between perihelion (closest approach to the sun) and the vernal equinox, affects the hemispheres oppositely, i.e., 180 degrees out of phase.

    Re: #175 (Timothy Chase)

    You are thinking of the tilt of the axis which controls the seasons. What about the eccentricity of the orbit? This is what would control the amount of radiation the climate system receives in a year. The more eccentric the orbit, the faster the earth will be moving when it passes close to the sun and the more time it will spend at greater distances from the sun. Greater eccentricity will mean less radiation being received throughout the year. And changes in the eccentricity of the orbit are predictable — given the gravitational effects of Jupiter and Saturn upon the earth’s orbit.

    While greater eccentricity does indeed mean earth moves faster when closest to the sun and slower when furthest, the overall effect averaged throughout the year is that earth receives slighly more solar energy when eccentricity is highest.

    I posted on these topics here and here.

    Comment by tamino — 3 Dec 2007 @ 2:43 PM

  177. Tamino (#176) wrote:

    While greater eccentricity does indeed mean earth moves faster when closest to the sun and slower when furthest, the overall effect averaged throughout the year is that earth receives slighly more solar energy when eccentricity is highest.

    I posted on these topics here and here.

    I appreciate the corrections — tilt vs. eccentricity in relation to the Milankovitch cycles was the one area that I felt uncomfortable with — although I had noticed the bit about the tilt causing more warming during a hemisphere’s summer near the corresponding pole for both hemispheres – without mentioning it. I should have followed that through further.

    I presume a smaller tilt cools the poles and the albedo effect causes the ice to spread towards the equator with positive feedback – despite the increased insolation in the region of the equator of itself. But in any case, I probably should have either not “addressed” this issue or should have taken the time to look more up.

    I will check out the links later today.

    Comment by Timothy Chase — 3 Dec 2007 @ 3:27 PM

  178. Quick Note: With regard to tilt and the Milankovitch cycles, I was wondering whether Singer et al. had made some sort of argument similar to what Ashley proposed in 166 and which tamino responded to in 176, and I found this:

    Introduction Understanding the causes of the Pleistocene ice age requires firm chronologic data on the growth and decay of glaciers in both hemispheres at all time scales. Glacier records 1993; Mercer, 1983). For example, such data can help determine whether the 100,000-year periodicity in the mid- to Late Quaternary paced large ice sheets and smaller mountain glacial systems in both hemispheres, which is not necessarily predicted from Milankovitch theory (Hays et al., 1976).

    -pg. 301

    *

    The Moreno I and II and Fenix ages, ca. 150,000–140,000 yr and 23,000–16,000 yr (Fig. 6), specifically imply that: (1) during at least the last two 100,000 yr glacial cycles, southern Andean and Northern Hemisphere glaciations were coeval and in the mid- to late Quaternary Period interhemispheric synchronicity of glacial maxima is the rule and not the exception; (2) the 100,000-yr eccentricity-based periodicity paces ice volume change in the middle latitudes of both hemispheres despite out-of-phase insolation, causing global ice age maxima (Imbrie et al., 1993).

    -pg. 312

    Cosmogenic nuclide chronology of pre-last glacial maximum moraines at Lago Buenos Aires, 468S, Argentina
    Michael R. Kaplana, Daniel C. Douglassa, Bradley S. Singera, Robert P. Ackertc, Marc W. Caffeed
    Quaternary Research 63 (2005) 301– 315

    In doesn’t out-and-out say what Ashley seems to think it did — but it seems designed to be interpretted in that fashion, namely that tilt can’t explain ice ages occuring in both hemispheres at the same time. And the references? Some appear to be to controversies long since resolved.

    Comment by Timothy Chase — 3 Dec 2007 @ 4:09 PM

  179. Re orbital parameters and climate, what do you think of Richard Muller’s theory of inclination driving ice ages?

    A New Theory of Glacial Cycles

    Spectral analysis of climate data and orbital parameters.

    For many decades it has been widely accepted that the 100 kyr cycle of the ice ages is caused by changes in the eccentricity of the Earth’s orbit. However this model is contradicted by high-resolution spectral and bispectral analysis of oxygen isotopes in sea-floor cores. Nonlinear models that depend on eccentricity or the envelope of the precession curve are also ruled out. We present an alternative theory: that the climate is related to changes in the Earth’s orbital inclination, and to varying extraterrestrial accretion as the orbit moves in and out of the Sun’s Zodiacal ring.

    Spectral analysis of 600 kyrs of global climate data is shown at right. The data show a strong peak at 100 kyr (Figures a and b) that the Milankovitch theory attributes to changes in the Earth’s eccentricity (Figure c). Comparison of the data (figures a and b) with the theory (figures c and d) show that the Milankovitch hypothesis does not properly account for the data. We proposed that changes previously ignored orbital parameter, the inclination of the Earth’s orbit, account for the 100 kyr cycle. The spectrum of these changes, shown in Figure e, is a good match to the data. The new theory provides an excellent match to the data, solves the “Stage-11 problem,” accounts for anomolous behavior seen in noctilucent clouds and He-3 data, accounts for the structure of the bispectra, and can be further tested by looking for cycles of iridium in Greenland ice. Recent measurements of He-3 in sea floor cores appear to confirm the theory.

    [Response: It's not so new anymore, and as I understand it, the requisite increased dust fluxes called for in the sediments have not been found. Maybe someone from his group can enlighten us as to its current status? - gavin]

    [Response: The "Muller and Macdonald" theory is all but dismissed now by serious researchers in the field. A nice, concise explanation of why is provided in this Science article by Clark et al (1999): Muller and MacDonald [ R. A. Muller and G. J. MacDonald, Science 277, 215 (1997)] argued that the origin of the 100-ky cycle involves non-Milankovitch changes in the Earth’s orbital inclination, which caused the Earth to periodically pass through a cloud of interplanetary dust. Sedimentary records and calculations of dust flux, however, do not show large changes in extraterrestrial dust accretion [F. Marcantonio, et al., Nature 383, 705 (1996); F. Marcantonio, et al., Earth Planet. Sci. Lett. 170, 157 (1999); S. J. Kortenkamp and S. F. Dermott, Science 280, 874 (1998)], whereas spectral analyses of the marine 18O record of global ice volume suggest that this mechanism is unnecessary [J. A. Rial, Science 285, 564 (1999); A. J. Ridgwell, A. J. Watson, M. E. Raymo, Paleoceanography 14, 437 (1999)]. Hardly a ringing endorsement. Muller’s “death star” hypothesis for explaining the major geological extinctions events including the K/T extinction, hasn’t fared much better. –mike]

    Comment by Jim Galasyn — 3 Dec 2007 @ 4:10 PM

  180. Re: Ice Ages

    It is no longer true that “For many decades it has been widely accepted that the 100 kyr cycle of the ice ages is caused by changes in the eccentricity of the Earth’s orbit.” The global climate forcing due to eccentricity is at most about 1.7 W/m^2, and that’s only when eccentricity gets as high as 0.06, which it very rarely does — the present value is more like 0.017, yet at present we’re solidly in an interglacial. Also, the timing of deglaciations doesn’t match the eccentricity cycle so well. These days, eccentricity forcing is generally considered just too weak to be a driver of glacial cycles.

    The orbital-inclination theory of Muller and McDonald caused a stir for a short time, but is no longer considered a serious contender.

    For over two million years, from about 3 million yr ago to about 750,000 yr ago, glacial cycles were overwhelmingly dominated by the 41,000-year obliquity cycle. This time period has even been called “The 41-kyr World” (Raymo and Nisancioglu 2003, Paleoceanography, 18, 1011). Only in the last 750,000 yr or so has a 100,000 year cycle been visible, and even that is not certainly a genuine cycle. Some researchers (I think Wunsch is one) propose that the recent changes are essentially stochastic, with the appearance of cyclicity an artifact of the very red noise character of the signal combined with a roughly 100,000-yr time scale (not period) in ice sheet dynamics. In any case, the 41,000-yr obliquity cycle and roughly 21,000-yr precession cycle are still clearly present in the Fourier spectrum of the last 750,000 years. Many theories have been proposed to explain what triggers deglaciation during the last 750,000 years, including synchronization of obliquity and precession cycles and the aforementioned stochastic behavior, and changes in the carbon cycle are implicated as well.

    My own “pet” theory revives the influence of eccentricity, but only in combination with obliquity, thus: when obliquity increases, the poles are more exposed to sunlight and the equator less so. Since the poles are highly reflective, this actually increases earth’s albedo and can explain the slight cooling which is sometimes observed just before a deglaciation. There is also less sunlight falling on the world’s oceans, which can further cool the oceans and initiate drawdown of CO2, helping explain the pre-deglaciation cooling, and may retard warming sufficiently to defuse a deglaciation unless polar warming is sufficient to disintegrate ice sheets. Only when obliquity nears its peak and eccentricity is increasing, can the greater ice melt from combined obliquity & eccentricity be enough to trigger deglaciation.

    Comment by tamino — 3 Dec 2007 @ 6:14 PM

  181. Re #169

    Ok Urs,

    >>What do you think about the composite of Dewitte et al. 2005 (IRMB)?

    IRMB alters some of the published data too, but in a way different from PMOD. ACRIM is the only composite that fits perfectly the published satellite data. PMOD fits the TSI proxy reconstruction by Lean, IRMB doesn’t.

    >>>The difference between PMOD and ACRIM before 1980 causes a more positive trend in the PMOD composite and thus does not explain the difference between the two trends, does it?

    No, Urs. What is important is not just the trend but the amount of TSI the Earth received for a given period. With ACRIM the earth received more irradiance because the maxima are higher.

    >>about the solar cycle length.

    It is not well understood how solar cycle length might relate to the TSI trend. That is why Lean and Solanki do not use it for their reconstructions.

    #173

    Gavin says: “So yes, there is at least one factor that amplifies some responses (regional patterns mainly rather than global mean temperatures), but that neither implies nor precludes other factors.”

    very well said!!!!!

    I suspect there are some other factors, but the model guys adopt a methodology that can only pick them up one by one and a little by little. That is why I thought an alternative method that tries to pick them all at once :)

    [Response: ... and then some. ;) - gavin]

    [Response: Further, positing the existence of a yet-unidentified hypothetical amplifying mechanism which acts on solar forcing but not on GHG forcing does not justify neglecting the known radiative forcing due to GHG increases. (that's the "and then some" business Gavin is referring to). To fail to treat this forcing on an equal and consistent physical footing with the unknown hypothetical forcing you are invoking is just bad science. --raypierre]

    Comment by nicola scafetta — 3 Dec 2007 @ 7:50 PM

  182. Solar forcing (direct and indirect modulation of clouds) drives abrupt climate changes?

    There seems to be strong evidence to support a solar forcing function for abrupt climate change.

    http://www.cosis.net/abstracts/EGU06/00841/EGU06-J-00841-3.pdf

    “This periodicity, initially associated with the so-called Dansgaard-Oeschger oscillations,is also found in a great variety of studies through the Holocene. The 1500-year period seems to occur independently of the general glacial – interglacial climate changes. According to these results, the millennial-scale variability was attributed to the same forcing, ruling out any direct link with the ice-sheet oscillations.”

    “Residual Delta14C time-series analyses confirm Bond’s hypothesis: solar forcing appears to be the dominant forcing during Holocene with two persistent periods of 2 500 and 1 000 years respectively.”

    From Wikipedia:

    “Gerard Bond suggests that changes in the flux of solar energy on a 1,500-year scale may be correlated to the Daansgard-Oeschger cycles, and in turn the Heinrich events; however the small magnitude of the change in energy makes such an exo-terrestrial factor unlikely to have the required large effects, at least without huge positive feedback processes acting within the Earth system.”

    My comment: The cyclic warming and cooling is driven by the solar influence on clouds? Has anyone read Palle’s papers?

    “Dansgaard-Oeschger events are closely related to Heinrich events. ….There is evidence to suggest Dansgaard-Oeschger events have been globally synchronous (Bond et al., 1999).”

    Link to Bond’s Persistent Solar Influence North Atlantic in the Holecence.

    http://www.deas.harvard.edu/climate/pdf/bond_2001.pdf

    “A solar forcing mechanism therefore may underlie at least the Holocene segment of the North Atlantic”

    Comment by William Astley — 3 Dec 2007 @ 11:20 PM

  183. N. Scafetta nicely gave me the file for TSI reconstruction of Wang et Lean 2005, on which IPCC AR4 best estimate is mainly based.

    I’ve some problem with the TSI trend, the same problem I met with the Crowley 2000 reconstruction used by Mann 2005. In fact, I’m quite astonished by the values Wang et Lean obtain.

    Fisrt point : if we take the 1910-40 trend (first signal of GW with 0,4 K trend), TSI variance from maximum to maximum is less than 0,2 W/m2, less from minimum to minimum. That is for TSI : the TOA forcing (Earth as a sphere and reflexivity) leads to a value of… 0,04 W /m2 maxi. Or other words : nothing or so. But if it is the case, we must say clearly that there’s NO solar influence at all for 1900-present T trend : 1910-40 warming is explained bu GHGs, less volcanism, intrinsic variability, without any significant solar forcing TOA. And if we suggest an influence (eg 10-20% of Gavin), we must explain how a 0,04 W/m2 TOA forcing would produce any significant effect on climate.

    Second point, not with absolute value, but with trend : I think RC contributors disagree with Wang et Lean when they say (frequently) there’s no trend since 1960. Because in their TSI reconstruction, maxima of cycle 21 (1981) and 22 (1989) are the highest of the past century, at the same value that cycle 19 (50s) and not far from cycle 23 (2002). In contrast, cycle 20 (1970) is less pronounced, so in Wang et Lean :
    a) there’s an increasing trend from the 1970s to the 1980s
    b) values of the 1980-present period are the highest of the century, with no other similar period in the previous decades for 3 successive cycles.

    Any way, this last point has no climatic sense when we consider the first, that is the extremely low absolute values of TSI change during the past 100 yrs.

    So, I see at least three hypothesis :
    - Wang et Lean (and other recent TSI rec. of the same magnitude) are wrong, and solar models miss an important point in proxies of past solar activity (before 1978 and satellite measur.) ;
    - Wang et Lean are right, TSI>TOA forcing is the good factor for understanding solar influence, and there is nearly no solar influence on modern GW (not solely since 1950, but for 1850-1950 as well)
    - Wang et Lean are right, TSI>TOA forcing is not the good factor for understanding solar influence, and we still miss the famous solar amplification mechanisms.

    Any preference in these hypothesis… or any other hypothesis ?

    Comment by Charles Muller — 3 Dec 2007 @ 11:49 PM

  184. Off topic but I’d really like to get your opinion regarding the recent paper by Roy Spencer (“Cloud and radiation budget changes associated with tropical intraseasonal oscillations”). It suggests that increased sea surface temperature in the tropics would result in reduced cirrus clouds and thus more infrared radiation leakage from Earth’s atmosphere which would be a negative feedback. My questions are as follows.

    1) Are you aware of any published reactions to the Spencer paper?

    2) Is it true that the circulation models assume that increased sea surface temperature would result in increased cirrus clouds which would have the effect of warming the sea surface further and thus there would be positive feedback? If so, can you point me to the main evidence supporting this assumption?

    Comment by Zelix — 3 Dec 2007 @ 11:59 PM

  185. #173, Charles, not bad arguments for a lay person. UV is better understood than you might believe. Especially since Dobson and his spectrometer. As far as I can read
    (and measure) UV has not changed that much, but stratospheric ozone did go for a wild concentration ride, for the better recently. Go back to 1997, it was a time when the Polar vortex was intense, at its center -80 C was reached, ozone concentrations dipped to its lowest values since measurements began. An excellent opportunity to study tropospheric warming by UV. Records show a small temperature increase for the Northern hemisphere in March 97, aside from that 1998, had double the temperature anomalies near +1 C, with lots more stratospheric ozone. I like the idea, of looking further, but I think that UVis not a significant temperature booster. Rather, as said many times here on RC, Antarctic ozone holes create substantial cooling. 1997 was the last cold Arctic winter spring I experienced, I know that many may enjoy -45 C for weeks on end, but the travel agencies kept it a secret then.

    Today is a different world, may be RC readers should consider last few days of explosive Arctic warming, over an astounding huge Polar swat, warmer than +10 C above average. Starting from where the open water and thin ice is, between Alaska and Russia. The speed of this warming was simply astonishing.

    http://www.cdc.noaa.gov/map/images/fnl/sfctmpmer_01a.fnl.anim.html

    Comment by wayne davidson — 4 Dec 2007 @ 12:24 AM

  186. #185 Wayne, thanks for the precision, I’m currently reading on that topic, so I’ve no clear idea for the moment. When I mentioned a solar influence stratosphere-troposphere coupling, I did’nt think to a direct and global effect of solar on stratospheric T, and then a transfer on troposheric T. Rather an influence on general circulation maybe mediated by planetary waves (but as I just open up these questions and as they’re quite complex, I won’t go further for the moment).

    I try to illustrate by an example : recently in J Clim, Lisan Yu analyzes oceanic evaporation (1958-2005, from Objectively Analyzed Air–Sea Fluxes OAFlux) and find a shift in 1977-78, with decrease before and increase after, and with 1990s as the most dramatic increase in Evp. (That’s perfectly coherent with the signature of 1977-2007 GW, by the way).

    An EOF analysis shows that the first factor of variance in Evp since 1977 is wind speed (the greater, the faster water vapor is blown away and the air–sea humidity gradients restablished). So, that is a kind of indirect effect I’ve in mind : in this case, any factor that influences wind speed (regionnaly on Tropics or subtropics for example) would influence evaporation, so convective-radiative budget, so Ts and Ttropo.

    Please, let’s be clear : I DO NOT say here that wind speed is influenced by solar variation!! I just give an illustration of the kind of an “amplification mechanism” we could imagine. But my example is clearly not adapted for the solar discussion (in fact, I don’t know if it is adapted to… anything, because in this case I don’t really understand why there would be decadal variations in wind speed and if there is, I suppose GHGs induced modification would be the first candidate). I’m going to read again and more carefully the paper Gavin, Mike on some others here wrote on regional response to Maunder minimum, in order to get a more realistic example of indirect mechanisms of solar influence.

    Comment by Charles Muller — 4 Dec 2007 @ 1:27 AM

  187. Re #185: Wayne, that link is quite a teaser. What can you say about it from a meteorological standpoint? Also, that whole area is pretty much in 24-hour darkness just now, right?

    Comment by Steve Bloom — 4 Dec 2007 @ 1:45 AM

  188. #184, on question 2, for instance this (not sure this is what you’re looking for)?

    On question 1, surprisingly no.

    Having read the paper myself (but not being a climatologist) I saw one big problem, not with the paper itself, but with the implication that this would be relevant to climate change. The paper doesn’t overstate its case and makes the caveat, e.g., that the time scales of the natural experiment described (weeks to months) and global change (decades) are quite different. But this is only part of a larger limitation: the mechanisms involved are quite different. The climate change mechanism is well known involving CO2, the tropical warming described has some other mechanism inside the weather system. What they have in common is temperature increase, but “correlation doesn’t prove causation”.

    The carbon dioxide is also relevant in another way. Without it increasing, what may happen as the troposphere heats up is that water will tend to condense out as liquid rather than ice. CO2 changes the vertical thermal structure of the troposphere, and the water may now condense out at a higher, colder level where ice again can form.

    Against Lindzen’s ‘iris hypothesis’ argues also the absence of evidence for significant forcing of this kind during the ice ages/interglacials. But that’s admittedly a very different regime from today.

    Real climatologists please correct me ;-)

    Comment by Martin Vermeer — 4 Dec 2007 @ 2:34 AM

  189. Charles — sorry, I didn’t see your post until late.

    Charles Muller (#171) wrote:

    AR4 is generally several years out of date : not really true, it would be foolish to imagine there’ve been a mass of ground-breaking research or observations in 2006-2007. Climate is a slow process… as well as climate sciences.

    Perhaps a couple would be more accurate. In any case, here is some of the news I know about from the past two years. I have divided it into three parts: Cryosphere and Sea Level, Carbon Cycle, and Clouds. It is by no means exhaustive. With more time, the list would undoubtedly be much longer.

    Cryosphere and Sea Level

    Their projections for Arctic sea ice showed it lasting from 2050 to well into the next century, but the sea ice extent in this year alone is 25% less than the previous recorded minimum of 2005, and estimates have been within the range of 2020 to 2040 — with a simple linear estimation of the behavior suggesting 2020. Likewise we have seen dramatic developements in terms of the glaciers of the Tibetean Plateau — which is now projected to be glacier-free by the end of the century.

    Currently we are seeing negative mass balance in both Greenland and Antarctica — with negative mass balance in Antarctica having occured only with the past few years and was discovered in 2006. Studies have shown that Greenland’s icemelt has increased by a factor of two and that icequakes have increased by a factor of three over the span of a decade. We have discovered a region within 310 miles of the South Pole that had melted for weeks in back in 2005 — but which was picked up through data analysis only much later.

    Carbon Cycle

    We are seeing positive feedback in terms of the carbon cycle – with several parts of the ocean in the Atlantic, Pacific and even Southern Ocean showing signs of becoming saturated. We are likewise seeing evidence of the weakening of the carbon sink provided by plants — at least during the warmer, drier years.

    Only within the past couple of years have we found that large parts of the permafrost are thawing. We have discovered that yedoma – a deep, especially methane-rich form of permafrost is roughly a hundred times more common that previously thought. Meanwhile, Global Climate Models which incorporate the carbon cycle exist — and received some small mention in AR4 — although they were not generally involved in making the climate projections.

    Clouds

    Just this year we found that there is an invisible twilight zone that extends for kilometers beyond the edges of visible clouds — and with this discovery should be able to improve our modeling of clouds and their effects. We have discovered that while the Asian Brown Cloud results in cooling at the global level, within much of Asia it amplifies warming.

    *

    Charles Muller (#171) wrote:

    More broadly, you repeat that GHGs is a very well known forcing. But I agree with that. You suggest in fine that climate sensitivity is a well constained domain: I strongly disagree with that – and I think there’s a consensus among scientists for recognizing WV and cloud feedbacks are still a major source of uncertainty for climate projections.

    Water vapor and cloud feedback is still a major source of uncertainty, although it is my understanding that this has been reduced. But results regarding climate sensitivity can be obtained which are largely independent of our knowledge of these feedbacks.

    There are two papers which combine the results from a great many studies to converge upon a high likelihood value of approximately of either 2.8 or 2.9. Now given the nature of climate sensitivity, a value which is considerably higher than the high likelihood is much more likely tha a value which is considerably lower. As such, the distributions which we are dealing with are highly asymmetric. Thus while the study based upon paleoclimate data cannot exclude considerably higher values, values which are substantially lower (e.g., 1.5) than the high likelihood value are effectively eliminated.

    The following post deals with one of these two papers: “Using multiple observationally-based constraints to estimate climate sensitivity” (2006) by J.D. Annan and J. C. Hargreaves that by means of Bayesian logic is able to combine the results from a variety of studies employing different methods for the estimation of climate sensitivity where the range of uncertainty is relatively high to constrain the uncertainty, producing a much tighter range. Thus for example, if one simulates the eruptions of Agung, El Chichon and Pinatubo using a simple energy balance model that has a tunable climate sensitivity, one finds that while the plausible range for each is fairly wide (with a lower limit of 0.3 to 1.8 and an upper limit of 5.2-7.7), the high likelihood value has 2.8 with a lower bound of 1.8 and an upper bound of 4.4.

    Of course this sort of approach simply as it applies to three eruptions may be somewhat biased. Nevertheless, by bringing in he results of numerous other studies using other methods and models provide similar ranges, and by a similar application of bayesian logic one is further able to constrain the range of uncertainty. The authors conclude that anything as high as 4.1 is highly unlikely, and the same would apply to values significantly below the high likelihood value of approximately 2.9 and a range from 2.6 to 4.1.

    24 March 2006
    Climate sensitivity: Plus ça change…
    http://www.realclimate.org/index.php/archives/2006/03/climate-sensitivity-plus-a-change

    There is a link to the actual paper in the article.

    The authors of the following paper give us a similar high-likelihood value based upon paleoclimate evidence. Although they cannot entirely exclude high climate sensitivities, they effectively rule out anything below 1.5 K per doubling, and their best fit for the past 420 million years using data compiled from 47 different published studies employing five different methods was for 2.8 K per doubling.

    Royer DL, Berner RA, Park J. 2007.
    Climate sensitivity constrained by CO2 concentrations over the past 420 million years.
    Nature, 446: 530-532.

    Neither of these studies would appear to be dependent upon our knowledge of the feedbacks due to water vapor or clouds. In fact, the study involving paleoclimates would appear to be entirely independent of such knowledge. The same is obviously true of volcanoes. And as I stated, many of the uncertainties will tend to cancel each other out. For example, greater cloud-formation will mean increased albedo, but they will also produce their own greenhouse effect.

    *

    Charles Muller (#171) wrote:

    You tell me that coupling of stratosphere and troposphere is well taken into account. Do you have any reference ? AFAIK, the SPARC (Stratospheric Processes And their Role in Climate) project, from WCRP is still going on. We don’t know precisely the role of dynamical and radiative coupling with the stratosphere in determining long-term trends in tropospheric climate, or even the exact way by which the stratosphere and troposphere act as a coupled system.

    What I said was that the coupling is already taken into account — not that all of the details have been worked out in terms of the chemistry or the modeling of all of the processes. But just because we don’t know everything (“even the exact way by which the stratosphere and troposphere act as a coupled system” as you put it) does not mean that we know nothing and are only able to model as much.

    The recent models include the stratosphere. The boundary which separates the stratosphere from the troposphere is called the tropopause. Models predicted that the tropopause would rise as the result of global warming. It has. They wouldn’t have been able to do this if they weren’t already incorporating the stratosphere. Likewise, I seriously doubt that they would have been able to model the Hadley cells to the point that they could be used to predict the expansion of the Hadley Cells — but all of the models in AR4 show it.

    And now the most recent NASA GISS model is now modeling the lower layers of the mesosphere.

    Please see:

    A full description of the ModelE version of the Goddard Institute for Space Studies (GISS) Atmospheric General Circulation Model (GCM) and results are presented for present-day climate simulations (c. 1979). This version is a complete rewrite of previous models incorporating numerous improvements in basic physics, the stratospheric circulation and forcing fields. Notable changes include the following: the model top is now above the stratopause, the number of vertical layers has increased, a new cloud microphysical scheme is used, vegetation biophysics now incorporates a sensitivity to humidity, atmospheric turbulence is calculated over the whole column, …

    Schmidt, et al., Present day atmospheric simulations using GISS ModelE: Comparison to in-situ, satellite and reanalysis data. (2006) J. Climate, 19, 153-192, doi:10.1175/JCLI3612.1.
    http://pubs.giss.nasa.gov/abstracts/2006/Schmidt_etal_1.html

    It is only by incorporating the stratosphere and our physical understanding of it that we can begin to compare the behavior of the model with the real world and thereby discover what important physical processes have been left out so that they too may be incorporated into the models. Incidentally, the paper by Schmidt et al describes some of the progress which has been made in the modeling of clouds – although it indicates that there is still more progress to be made.

    Comment by Timothy Chase — 4 Dec 2007 @ 4:00 AM

  190. Wayne 185! Can you please help me understand that animation you pointed us to? It refers to surface temperatures. Is it really saying that over the last few days surface temperatures over the Arctic have moved up by 15 to 20C?!?!!? Really??! Are surface temperatures the air teperature at the surface or the temperature of the surface? Either way …!

    Comment by Nigel Williams — 4 Dec 2007 @ 5:44 AM

  191. Timothy Chase wrote:

    [[The more eccentric the orbit, the faster the earth will be moving when it passes close to the sun and the more time it will spend at greater distances from the sun. Greater eccentricity will mean less radiation being received throughout the year.]]

    Actually, it’s the opposite — because of the inverse square law, a more eccentric orbit actually gets a little more insolation than a perfectly circular one. The difference is very small, though. The ratio is equal to 1 / sqrt(1.0 – e^2) where e is the eccentricity. Earth’s eccentricity varies from about 0.00 to 0.05, so at maximum eccentricity Earth receives about 0.125% more insolation than at minimum.

    Comment by Barton Paul Levenson — 4 Dec 2007 @ 6:30 AM

  192. Wayne@185. That’s stunning warming in the Arctic over the last week. What sort of weather system is driving that? It shows the pole warmer than -5, in the middle of the polar night.
    Could it be an instrumental blip?

    Comment by Nick Barnes — 4 Dec 2007 @ 9:34 AM

  193. tamino@180: presumably the effect of eccentricity on forcing depends on the phase of the eccentricity with regard to the axial tilt. Not sure what the right terminology is here, but at the moment perihelion is close to the southern solstice, when albedo is high (highest?). I imagine that at other epochs perihelion might be close to the northern solstice, or close to an equinox. Because the earth’s albedo depends on this phase, the effect of eccentricity won’t be constant.

    Comment by Nick Barnes — 4 Dec 2007 @ 9:38 AM

  194. Re the Muller-MacDonald theory in 179, thanks to Mike and Gavin for the detailed replies.

    Comment by Jim Galasyn — 4 Dec 2007 @ 10:34 AM

  195. Nigel, 185-190 — remember the projection. The huge expanse of ‘white’ at the top of that rectangle is actually a point (the North Pole). So when it changes from white to dark red, it does seem to indicate the North Pole warmed that much, that fast. But is there a data set we can check? a polar projection might be far more informative. Anyone know more?

    Comment by Hank Roberts — 4 Dec 2007 @ 10:50 AM

  196. I’ve got to encourage people who haven’t yet looked at the temperature anomaly animation linked to in 185 to do so. It’s like something out of a science fiction movie.

    The recent big glop of cold temps in the central plains shows up clearly, but the anomaly to the north looks like something that Kurt Russell’s superiors would send him to investigate. Off the charts, I suspect, like the French heat wave of a few years back.

    Comment by Jeffrey Davis — 4 Dec 2007 @ 11:02 AM

  197. 167-190-192… Its legit at least in my location, 74 43N 94 57W.
    or in the Canadian sector of the Pole:

    http://www.weatheroffice.gc.ca/data/analysis/jac06_100.gif

    Its the warmest temperature boost measured in December here, beating 2005 and 2006, the latter being very warm winter. I am baffled by this speed, although I observed several Cyclones hitting towards the Pole over the last 12 days, mainly from the Pacific, some from the Atlantic It may be a cumulative effect of warming from above combined with warming from below, the thin ice multiple thousand extra leads open water. It can be something else. But the key is for sure the thin ice and open water. These are anomalies which are extraordinary. Another point, the coldest air is in the NWT-Yukon-Alaska region, prompting an antycylone which may pump further warm air towards the Arctic.

    Comment by wayne davidson — 4 Dec 2007 @ 11:33 AM

  198. Re 185. Winds, probably. Thin ice breaks and waves mix the waters.

    An Arctic sea ice area time series is found on page http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg As the winds come and go, there are typically several dips in the ice area each winter. The long term trend is clearly diminishing.

    Sea surface temp anomalies in polar projection can be found at
    http://sharaku.eorc.jaxa.jp/cgi-bin/amsr/polar_sst/polar_sst.cgi

    Comment by Pekka J. Kostamo — 4 Dec 2007 @ 11:42 AM

  199. Barton Paul Levenson (#191) wrote:

    Actually, it’s the opposite — because of the inverse square law, a more eccentric orbit actually gets a little more insolation than a perfectly circular one. The difference is very small, though. The ratio is equal to 1 / sqrt(1.0 – e^2) where e is the eccentricity. Earth’s eccentricity varies from about 0.00 to 0.05, so at maximum eccentricity Earth receives about 0.125% more insolation than at minimum.

    Yep.

    Tamino corrected me on this as well. But your explanation in addition to his will help. I can see how combined with Kepler’s second we could set this up as a differential equation then integrate. A slightly different angle of attack, but it should come up with the same results as what Tamino arrived at. And as I differential equation I believe I can see already why it should be slightly more.

    Comment by Timothy Chase — 4 Dec 2007 @ 12:31 PM

  200. While AGW skeptics may find their arguments to be a form of entertainment, or mental gymnastics, it appears that the rest of society, including the business community, has moved on and is putting time and energy (mental energy, at least) into solving the problems posed by AGW:

    THE NATIONAL COUNCIL FOR SCIENCE AND THE ENVIRONMENT invites you to participate in the 8th National Conference on Science, Policy, and the Environment, Climate Change Science and Solutions to develop comprehensive strategies for protecting people and the planet against the impacts of global climate change.

    January 16-18, 2008

    Ronald Reagan Building and International Trade Center, Washington, DC

    CEO OF DUKE ENERGY, JAMES ROGERS to deliver a keynote address on The Case for Business Leadership. JOIN US in learning about solutions to climate change from Rogers and other leading experts and innovators…

    http://www.NCSEonline.org/2008conference

    Comment by Chuck Booth — 4 Dec 2007 @ 12:53 PM

  201. PS to Barton

    On the way to get coffee — bring in Thermo’s First and you can drop Kepler’s Second.

    Comment by Timothy Chase — 4 Dec 2007 @ 1:12 PM

  202. Again, at the risk of going off-topic (the more relevant threads have been closed to comments, or are showing waning interest), the following might be of interest to RC visitors, esp. those debating policy and technological solutions:

    A Convenient Guide to Climate Change Policy and Technology

    published by the Climate Change Policy Partnership at the Duke University Nicholas School of the Environment and Earth Sciences and Nicholas Institute for Environmental Policy Solutions
    Center on Global Change

    “Scientific consensus, growing public awareness and political change may soon drive the United States to a mandatory climate policy. Fossil fuel-generated electricity accounts for one-third of carbon dioxide emissions in the United States; electric utility companies can therefore provide leadership in technology and policy development through careful investment decisions for future generation capacity. This 420-page guide from the Nicholas Institute and Duke’s Center on Global Change examines technology options for reducing utility-generated greenhouse gas emissions and reviews policies to achieve reductions.”

    http://www.nicholas.duke.edu/ccpp/convenientguide/

    Comment by Chuck Booth — 4 Dec 2007 @ 1:12 PM

  203. Check out the NOAA SST historical database. The artic ocean north of Norway/Finland/Western Russia almost always shows strong positive SST anomalies, going back for at least five years that I checked. I think the SST database only goes back 20 to 25 years, so either was an early history of much colder water at those locations or something is wrong in the reporting. Maybe the area had historically been covered with ice and the SST calculation has trouble dealing with that.

    Comment by B Buckner — 4 Dec 2007 @ 1:16 PM

  204. In addition to gale force winds, there has also been a strong flow of warm Pacific air via the Bering Sea. Jim Andrews at Accuweather has written a piece:
    http://www.accuweather.com/news-blogs.asp?partner=accuweather&blog=andrews

    Comment by Pekka J. Kostamo — 4 Dec 2007 @ 1:23 PM

  205. Hank Roberts (#195) wrote:

    a polar projection might be far more informative.

    How about Peter’s Projection? Project horizontally onto a cylinder and an area on the map will be proportional to the area on the globe. In any case, the sea ice area is still climbing according to Cryosphere Today, but the anomaly is has dipped back down again – although it looks like it’s begun to climb back on the monthly.

    Comment by Timothy Chase — 4 Dec 2007 @ 1:42 PM

  206. Thanks for the several pointers Pekka, very helpful to have the polar projection.

    Jim Andrews comments that he doesnt’ have access to info from the area, but the US Navy certainly does.

    This is from several years ago, a Google grab’n'run, I’m sure there’s more recent info. Anyone know where to find it?

    4/23/2003
    http://www.onr.navy.mil/media/article.asp?ID=58
    Office of Naval Research Sends Scientists to Arctic Ice Camp

    In late March [2003], the U.S. Navy established a camp on a severe and unforgivingly cold stretch of ice about 150 miles north of Deadhorse, Alaska…..

    … “Rapid change in Arctic temperature is like the canary in the coal mine,” explains Dennis Conlon, Arctic scientist at ONR. “Arctic ice cover affects Earth’s temperature. The less ice there is to reflect sunlight back into space, the warmer we get. This ice camp gives researchers the chance to gather data and to help the Navy better understand the Arctic operational environment.”

    Comment by Hank Roberts — 4 Dec 2007 @ 1:57 PM

  207. Martin Vermeer (#188) wrote:

    Having read the paper myself (but not being a climatologist) I saw one big problem, not with the paper itself, but with the implication that this would be relevant to climate change. The paper doesn’t overstate its case and makes the caveat, e.g., that the time scales of the natural experiment described (weeks to months) and global change (decades) are quite different. But this is only part of a larger limitation: the mechanisms involved are quite different. The climate change mechanism is well known involving CO2, the tropical warming described has some other mechanism inside the weather system. What they have in common is temperature increase, but “correlation doesn’t prove causation”.

    Spencer is studying the Madden-Julian Oscillation as a means of determining the effects of higher temperatures upon cloud formation over the ocean. But there is only one problem: as this is an oscillation, what you are dealing with is periodic behavior which by its very nature dynamic, not static, yet you are trying to draw conclusions about what will essentially be static from it – what happens when the higher sea surface temperature forces the system to equilibrium – and the clouds that are associated with that equilibrium.

    To see the problem with this, imagine trying to calculate the relationship between the climate’s sensitivity to solar insolation – on the basis of the difference in temperature between day and night. Obviously you can’t draw a conclusion regarding the temperature that the earth would be if days were as dark as nights simply on the basis of how cold the nights are – because nights haven’t had the chance to achieve equilibrium.

    Anyway, a slightly wordier way of what Gavin gave some time ago — but essentially the same response as what you gave.

    Comment by Timothy Chase — 4 Dec 2007 @ 2:06 PM

  208. RE: # 185

    Wayne, you mentioned in # 197:

    [I observed several Cyclones hitting towards the Pole over the last 12 days, mainly from the Pacific, some from the Atlantic ]

    If intense wave action broke, scattered and shoved aside massive expanse of thin, new ice an equally massive surface of open water with warmer water from below upwelling and releasing heat suddenly that would account for the extraordinary spike in temperature.

    The rapid formation of new ice means it is likely very thin and the link Pekka provides at # 198

    [An Arctic sea ice area time series is found on page http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg As the winds come and go, there are typically several dips in the ice area each winter. The long term trend is clearly diminishing.]

    indicates this rapid freezing could not have added much thickness to the new ice surface.

    Thus, heavy wave action broke up ice and allowed warm upwelling seawater to the surface to give a huge jolt of heat to the atmosphere in a very short period of time.

    Comment by John L. McCormick — 4 Dec 2007 @ 3:14 PM

  209. RE # 205

    Timothy, you said:

    [the sea ice area is still climbing according to Cryosphere Today, but the anomaly is has dipped back down again - although it looks like it’s begun to climb back on the monthly.]

    Look at the link Pekka provided at:

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg

    and note the exceedingly rapid increase in ice area and you will not find a similar event elsewhere on that graph.

    Rapid freeze over a few week period means very thin ice prone to rapid destruction by intense wave and wind action.

    Comment by John L. McCormick — 4 Dec 2007 @ 3:36 PM

  210. RE # 185

    Wayne:

    Jim Andrews at Accuweather provides the gridded data (surface temperature) for 11/29 and 12/2.

    Look at the temperature changes from Thursday to Sunday and you will see the graphic of the great red temperature explosion.

    Arctic Warming

    Thursday, November 29, 2007 and Sunday, December 2, 2007

    http://www.accuweather.com/news-blogs.asp?partner=accuweather&blog=andrews

    Comment by John L. McCormick — 4 Dec 2007 @ 3:50 PM

  211. William Astley (#182) wrote:

    “Residual Delta14C time-series analyses confirm Bond’s hypothesis: solar forcing appears to be the dominant forcing during Holocene with two persistent periods of 2 500 and 1 000 years respectively.”

    Bond? You are doing better. He gets cited by those who discount the greenhouse effect, but he himself of course recognized it. How could he not? Its grounded in solid physics. And carbon cycle feedback would have amplified such solar oscillations. Likewise, I doubt that any competent climatologist would fail to recognize that solar was the dominant forcing throughout all of the Holocene — prior to the 1800s.

    However, the oscillations that he argued for were considerably weaker than the Dansgaard-Oescher oscillations — although presumably a continuation of them into the Holocene. But I personally don’t know how well his theory has held up. And in any case, the oscillations would have still been local — as the southern hemisphere would have dipped whenever the northern hemisphere rose.

    *

    It would appear that best estimates, the Holocene maximum was set roughly 7500 — prior to being shattered in the late twentieth century.

    Please see:

    Holocene climatic optimum
    http://en.wikipedia.org/wiki/Holocene_climatic_optimum?uselang=en

    If I remember correctly the data would seem to suggest that we are already above any temperature that has been reached in the past half-million years. And we are still climbing.

    PS

    Sources for the data off which the graph is based are given with the most recent being 2004.

    Comment by Timothy Chase — 4 Dec 2007 @ 3:52 PM

  212. ..and so (if my simple appreciation of weather-drivers holds) all that warming air will now be rising in cells and pulling more air in from someplace else. And that new air will be warmer still. A nice positive feed-back. Flip or tip?!?!

    Comment by Nigel Williams — 4 Dec 2007 @ 4:10 PM

  213. Ref 209 John McCormick writes “Rapid freeze over a few week period means very thin ice prone to rapid destruction by intense wave and wind action.” I tried the Pekka piece (198) for the reference, but could not find it. Could you give me a reference where this is shown to be true?

    Comment by Jim Cripwell — 4 Dec 2007 @ 4:12 PM

  214. ..and of course wind velocity will be increasing as the temperature differential increase – which will increase the upwelling of the arctic ocean – which will – … oh darn!

    Comment by Nigel Williams — 4 Dec 2007 @ 4:14 PM

  215. John L. McCormick () wrote:

    Look at the link Pekka provided at:

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg

    and note the exceedingly rapid increase in ice area and you will not find a similar event elsewhere on that graph.

    I believe the anomaly minima was reached around October 1, and that would have been when the rise you are looking at begun. There has been a smaller dip just recently, but a rise has begun again. But yes, the ice is quite thin at this point.

    I am somewhat higher than 50/50 on whether we will set a new minima this coming year. Dramatic minima aren’t usually broken the following year — but there is the positive feedback, and it would appear to be fairly strong. However, that opinion is probably not worth much more than a plug dollar — even with inflation.

    Comment by Timothy Chase — 4 Dec 2007 @ 4:23 PM

  216. Did the article you would have ‘flunked’ (had they been written by students) pass peer review? If you are correct, does this not imply that the quality of the peer review process for the climate sciences is appalling bad? If so, how can other articles be trusted if their primary defence is ‘peer review’ as is regularly asserted by environmentalists and the media? As I have an interest, but no expert knowledge in the climate sciences, how am I to therefore evaluate of the quality of any of the published papers?

    [Response: "Peer Review: A Necessary but not Sufficient Condition". - mike]

    Comment by Will Nitschke — 4 Dec 2007 @ 4:31 PM

  217. re: Jim C. @ 213
    Perhaps I am missing something, and I am open to correction, but which part of John M.’s statement strikes you as being a non-obvious or requiring study? To put it another way, can you imagine any plausible scenario in which the recently, rapidly reformed ice isn’t thin? Or any reason why thinner ice wouldn’t be more easily broken up than thicker ice?

    Comment by Kevin Stanley — 4 Dec 2007 @ 5:55 PM

  218. Since Palle has come up in this thread a few times, brief excerpts from a couple of articles detailing some of the problems with his approach, one being from Real Climate itself….

    First, it appears that he wasn’t taking into account the greenhouse effect that results from clouds in his calculation of the effects of reduced cloud-cover…

    Wielicki leads the science team of a mission called CERES – the Clouds and the Earth’s Radiant Energy System…

    Without measuring both, he explains, you cannot infer anything about warming. CERES data, for example, show that clouds not only reflect lots of visible light, they also act like a blanket and trap infrared radiation in the lower atmosphere. The two effects almost cancel out, so there is little overall change in the energy the atmosphere retains.

    A further objection is that direct telescope measurements of earthshine in Palle’s study only start in 1998 [ending in 2000, but performed again -- except where the trend had actually reversed itself]. The data for the previous 14 years is based on satellite measurements of clouds which were used to calculate an estimate of earthshine.

    ‘Earthshine’ fall heats global warming debate
    19:00 27 May 2004
    NewScientist.com news service
    Jenny Hogan
    http://www.newscientist.com/article/dn5048.html

    Second, it appears that he was greatly overestimating the presumed changes in cloud-cover…

    The ISCCP group produces an independent estimate of the albedo, from performing a full radiative flux calculation that takes into account observations of all radiative forcings and produces top of the atmosphere, surface, and in-atmosphere fluxes (data, figure right). This has been shown to be in excellent quantitative agreement with satellite measurements at the top-of-atmosphere and with surface measurements. The year-to-year variations of these values show some qualitative agreement with the earthshine-trained ISCCP reconstruction but very large quantitative differences.

    The ISCCP estimate (right) shows a decreasing albedo trend of 1-2% in the 80s and 90s (as opposed to 7-8% in the earthshine-based proxy), a small increase of 1% form 1999 to 2001 and a flattening of the curve in the last three years. Quantitatively similar trends are derived from radiative flux retrievals by the ERBS and Terra and Aqua satellites.

    Cloudy outlook for albedo?
    22 February 2006
    by George Tselioudis (NASA GISS)
    http://www.realclimate.org/index.php/archives/2006/02/cloudy-outlook-for-albedo

    Third, the trend reversed itself in recent years. Fourth, qualitatively the measurements which he describes would seem consistent with solar brightening as the result of declining aerosols. And if so, so much for any connection to cosmic rays.

    Have I missed anything?

    Comment by Timothy Chase — 4 Dec 2007 @ 6:47 PM

  219. Ref 217. I live in Canada. I have spent time in winter in Fort Churchill. So far as I am aware, ice thickens according to Newton’s Law of Cooling. If the air temperature is cold enough, ice thickens very fast indeed. I have seen no mention of what the temperature was where the ice froze, My guess is if the surface was covered fast, the air temperature was very cold, and the ice would thicken very fast. Here in Ottawa with temperatures only down to -30 C, the ground will freeze to 7 feet in two weeks, providing there is no snow cover.

    Comment by Jim Cripwell — 4 Dec 2007 @ 8:00 PM

  220. Re #207: Just to add that the reduced sensitivity that Spencer says is implied by his results runs into insurmountable difficulties when paleoclimate is considered. The deglaciations, e.g., involve some pretty sharp temperature increases that are hard to imagine if tropical warming is damped like that.

    My impression is that the Spencer paper (and let’s not forget the co-authors, including Christy) is considered to be pretty much in the “not even wrong” category, and so is not deserving of a formal reply.

    If someone does write a reply, though, I have a suggested title for them:

    “Far from the Madden crowd: Spencer julienned”

    Comment by Steve Bloom — 4 Dec 2007 @ 8:10 PM

  221. For Will Nitschke #216 and the other nonscientists here, peer review is a minimum standard. It is a determination by a few experts in the field that an article is of sufficient interest to the larger community that it merits publication and consideration by that larger community. The community of experts then decides on how correct and important the work is–as measured by, for example, the number of times the work is cited in other peer-reviewed articles. Suffice to say, I don’t think Rasmus (or most other climate scientists) will be citing S&W except as a strategy that doesn’t work.

    Comment by Ray Ladbury — 4 Dec 2007 @ 8:28 PM

  222. Jim Cripwell (#213) wrote:

    Ref 209 John McCormick writes “Rapid freeze over a few week period means very thin ice prone to rapid destruction by intense wave and wind action.” I tried the Pekka piece (198) for the reference, but could not find it. Could you give me a reference where this is shown to be true?

    Kevin Stanley (#217) asked:

    re: Jim C. @ 213
    … can you imagine any plausible scenario in which the recently, rapidly reformed ice isn’t thin? Or any reason why thinner ice wouldn’t be more easily broken up than thicker ice?

    … in response Jim Cripwell (#219) wrote:

    Ref 217…. Here in Ottawa with temperatures only down to -30 C, the ground will freeze to 7 feet in two weeks, providing there is no snow cover.

    Just out of curiosity, how quickly does land flow in Ottawa, and how big are the waves?

    Comment by Timothy Chase — 4 Dec 2007 @ 8:55 PM

  223. RE # 213

    Jim, compare the Nov 27 with the Dec 4 and I believe you will notice a decreased ice cover on Dec. 4. It was during the Nov 27-Dec 4 several cyclones visited the Western Arctic according to Wayne Davidson. Very thin ice and strong wind and wave action likely caused the decrease by Dec. 4.

    Dec. 4: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071204.jpg

    Nov. 27 http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071127.jpg

    Comment by John L. McCormick — 4 Dec 2007 @ 9:45 PM

  224. Re :185 http://www.cdc.noaa.gov/cgi-bin/HistData/fnl.pl?date1=&date2=&days=1&va
    r
    Arctic is very warm now. Link:http://www.cdc.noaa.gov/cgi-bin/HistData/fnl.pl?date1=&date2=&days=1&var=Air+Temperature&level=2000&type=1&proj=Northern+Hemisphere&custproj=Cylindrical+Equidistant&xlat1=&xlat2=&xlon1=&xlon2=&labelc=Color&labels=Shaded&cint=&lowr=&highr=&scale=200&Submit=Create+Plot

    Comment by Fieldhouse — 4 Dec 2007 @ 9:50 PM

  225. #210 John, It went warmer than the grid as on the link, not only on the surface but the tropopause reached 11 to 12 kilometers! Again I stress this is a new Arctic disorder of weather, especially completely different temperature wise, your assessment basically means shallow ice thickness and open sea coverage is intertwined with atmospheric temperatures in darkness especially as Nigel wrote in 214, if winds are involved. Current sat pics show numerous almost countless leads where the Arctic Ocean open water was in September. For those of us experienced in looking at Polar sat pics of the 80′s and 90′s, this open water amongst thinner ice is a new landscape near the pole of November and December. Given calm wind conditions, it got cold, almost normally cold, after all darkness makes the Arctic what it is. The Accuweather meteorologist called this temperature boost a “freak” event, true enough, it use to be a freak rare event, but now things are changing to the point where it’s becoming very common.

    How then did it come to this? On topic, the sun is nowhere to be found, we are at a solar minima, -5 at the Pole in December. Surely there is more energy from atmospheric chemistry, in its properties of heat retention with its various radiative mechanisms, than a sun quiescent, hidden in the Earth’s shade.

    Comment by wayne davidson — 4 Dec 2007 @ 10:46 PM

  226. I am somewhat higher than 50/50 on whether we will set a new minima this coming year.

    Timothy how about a wager on that? $100 (or Euros) says it 2008 minima > 2007

    Comment by Joe Duck — 5 Dec 2007 @ 1:00 AM

  227. Sorry I am not implying that peer review is without limitations. But I am wondering (as a non-scientist but someone who does work in a technical field) that if the published paper is of such poor quality that it would get an ‘F’ if done by a student, then:

    1. Is climate sciences in a state of shambles?
    2. Is the reviewer using hyperbole in expressing this opinion?

    Would one get a paper published in a medical journal if the author of the paper would not even get a pass mark on it as an undergraduate?

    Are other established scientific fields so contentious over particular issues? I am finding my reading of the ‘pro’ and ‘anti’ CO2 hypothesis literature disturbingly ‘filtered’ by all sides of the debate.

    [Response: No, climate science is not in a shambles. Most papers that pass peer review are correct; many of them are uninteresting and never get read, but the filter works reasonably well. Some papers are (mostly) technically correct in their execution but make dubious assumptions and draw unfounded conclusions. The paper by S&W under discussion here is in that category. No one paper that passes peer review can be taken on that basis as absolute truth. You have to look at the ensemble of what is published, and on the follow-up in other papers. There is no replacement for actual understanding of the contents, and in the absence of time or background to
    do that, one must settle on reliable authorities (like IPCC) to do the vetting for you. Still, I think many of the fundamental issues are readily accessible to the lay reader, even if making sense of the vast literature can be overwhelming. --raypierre]

    Comment by Will Nitschke — 5 Dec 2007 @ 1:50 AM

  228. RE 221 Ray,

    when you guided this discussion from disorder back to the main topic of the title, the Sun, I see you have yet no comments on the study

    Usoskin, Ilya G., and Gennady A. Kovaltsov, 2007. Cosmic rays and climate of the Earth: possible connection. Comptes Rendus Geoscience, accepted October 30, 2007, in press, online http://cc.oulu.fi/~usoskin/personal/CRAS2A_2712.pdf

    I copy what Ilya thinks an interesting relation:

    “Numerous studies (see reviews [16,81,91]) confirm a
    relation between solar/CR activity and different indices
    of climate behaviour (e.g., d18O or drift ice debris [8]) during the Holocene.

    For example, there is an apparent agreement between
    the grand minima of reduced solar activity and cold/wet
    climate episodes (see, e.g., review [91]). Fig. 4 confronts a physics-based reconstruction of the solar activity from the 14C data [69,87] with periods of identified sudden climatic shifts to cold/wet conditions in Europe during the last 7000 years [7,49]. One can see that they tend to appear during the grand minima periods.We note that 12 out of 14 climate shifts after 5000 BC occurred during grand minima of solar activity identified by Usoskin et al. [87], giving a 86% hit rate. On the other hand, only 3 (ca. 4200 BC, 700 AD and 1050 AD) out of 15 grand minima identified for the same period are not accompanied by climate shifts (80%hit rate). This also suggests, with high significance, a close relation between shifts of the climate type and solar activity (cosmic rays), at least in the European region. Although such studies cannot distinguish whether the primary effect is via CR or solar irradiation (e.g., [17]), an analysis of the geomagnetic field variation may help in disentangling the mechanisms (see a subsequent section).

    In summary, there is a set of evidence that the solar variability affects the climate changes on centennial-millennial time scales, but it is hard to distinguish the role of cosmic rays, and the exact mechanisms need to be resolved.”

    Well, we all know that mere correlation proves nothing, but a 86% hit rate may not be a coincidence only?

    Comment by Timo Hämeranta — 5 Dec 2007 @ 3:00 AM

  229. Timo,
    I’m afraid I am a bit of a skeptic when it comes to GCR/solar variability and climate. First, trying to extract a periodicity from paleoclimate data is a little like trying to find a needle (a particular one) in a stack of needles. It’s rather like epidemiological studies in medicine–unless you have a theory to guide you, how do you guard against what we in particle physics used to call “bump hunting”. I’ve seen 4-sigma signals emerge from known background. Along these lines, you have to make a distinction between a priori predictions and a posteriori studies–you need a much more significant correlation for the latter to be statistically significant.
    Space radiation is a part of my day job, so, I am somewhat familiar with efforts to reconstruct past solar history. They are quite problematic. Shea and Smart looked in detail at this, and I’m not sure even they fully believe their reconstruction. Certainly they take it with enough salt to risk raising blood pressure. Don’t get me wrong. It’s good work. Ilya’s paper (what little I’ve had time to read) looks good, too. It’s just that there are a lot of things that vary as the Sun varies, and without a detailed physical model, it’s very hard to avoid going down a lot of blind tracks.
    I think this work is important–especially as we start trying to refine GCMs and make regional predictions (after all, availability of cloud nucleation sites probably varies a lot regionally). However, because clouds both warm and cool, I don’t expect that this work is going to revolutionize our understanding of global climate. We’ll still find that increasing CO2 increases the energy in the climate–and probably magnitudes will not change that much. Thanks for the link. Oh, btw, you might suggest to Usoskin doing a Monte Carlo study to determine statistical significance. I think it would be useful both for the Grand Max/Min paper (to see if the clustering around the “2nd mode” is significant) and for this paper as well (looking at how often “noise” with various characteristics returns a positive correlation.

    Comment by Ray Ladbury — 5 Dec 2007 @ 9:36 AM

  230. Given wayne davidson’s posts, I’m curious about the next addition to this graph:

    http://www.arctic.noaa.gov/reportcard/images/essays/atmosphere/figa1.gif

    Comment by J.C.H. — 5 Dec 2007 @ 9:47 AM

  231. Will Nitschke, What “sides” of the debate are you referring to? Do you know of a single scientific society that has advocates a theory other than anthropogenic CO2? Do you know of any studies by climate scientists in peer-reviewed journals that suggest any well developed theory other than anthropogenic CO2?
    Look, peer review is a floor. I recently reviewed an article that was absolutely incorrect technically, but still contained some interesting ideas and perspectives. Rather than reject the article out of hand, I took the time to make suggestions of things that needed to be corrected and additional work that needed to be done. It was my fervent hope that the authors would look at the mountain of work I had suggested and go away. They did not. Rather, they took most of my suggestions and the second draft was much improved. After 2 or 3 iterations, the article was still flawed, but much improved, and it still had the potential of sparking some interesting discussions. I noted the remaining flaws, but said I would not recommend rejection. My rationale is that my colleagues are big boys and girls and can spot crap in an article, and maybe someone can take the interesting ideas and foster discussion or develop them further.
    An article doesn’t have to be perfect to merit publication. Also, some journals have higher standards of “perfection” than do others. I’m just curious where you are getting your ideas if you think current climate science is deeply flawed.

    Comment by Ray Ladbury — 5 Dec 2007 @ 9:47 AM

  232. Ref 222 Timothy writes “Just out of curiosity, how quickly does land flow in Ottawa, and how big are the waves?” I am not aware that Newton’s Law of Cooling has different effects if one surface is water or land. As a matter of interest, the land is much warmer than the oceans, so it is more difficult for the frost to penetrate in Ottawa compared with the Arctic Ocean.

    Comment by Jim Cripwell — 5 Dec 2007 @ 10:33 AM

  233. Jim Cripwell (#232) wrote:

    Ref 222 Timothy writes “Just out of curiosity, how quickly does land flow in Ottawa, and how big are the waves?” I am not aware that Newton’s Law of Cooling has different effects if one surface is water or land. As a matter of interest, the land is much warmer than the oceans, so it is more difficult for the frost to penetrate in Ottawa compared with the Arctic Ocean.

    You are forgetting the thermal inertia. Oceans have a great deal more of it than land does. However, you are right about snow. Works the same way with the ocean as it does with land. But there are some additional complexities involved. With ice, leeds form when the ice gets cracked. In the Arctic the will mean frost steam and the fissures will rapidly refreeze — something which actually works in your favor.

    But then there is the fact that ocean water is especially dark. It is a good thermal radiator. I doubt the same can be said of ice. And there will be cooler layers of water which will insulate the warmer water below. Then there are the darker pools which form at the surface in the spring. That might drain away of course, but only once it melts through to bottom of whatever ice it is on.

    First year ice will tend to have brine. As soon as it begins to melt, the brine goes first, and you are left with honeycombed “rotten ice” which is especially susceptible to mechanical forces and melt. Likewise, first year ice rarely gets more than three meters deep.

    Finally, you will always have currents of water below, and stronger poleward currents of warm water have been more common in recent years, and convection will play a greater role in the spring. These aren’t sort of things you have to worry about with land.

    Comment by Timothy Chase — 5 Dec 2007 @ 1:53 PM

  234. RE:232
    I think Timothy’s point was that ocean turbulence will slow down freezing. You can verify this in your back yard. Go outside with two buckets of water when the temp is less that 0C. Stir one constantly. Observe any difference in rate of freezing.

    Of course, as you imply, the ‘thin ice is breaking up in storms” hypothesis is currently speculative, at least for you and I. Others may have the proof you requested, and I’d like to see it, too. E.g. Wayne Davidson(225) said “Current sat pics show numerous almost countless leads where the Arctic Ocean open water was in September.” Wayne, if those current sat pics are available for public consumption, maybe you could provide links?

    It seems extremely likely that ice formed in the last couple of months or so over area that had been open sea is thinner than the multi-year ice . Can we agree on that much, Jim? Whether the ice is “thin” or “thick” depends on how we operationalize those terms. So the new ice may or may not be “thick” by your definition of that word, or mine, but perhaps we can agree that it is very likely thinner in the recently frozen areas than in the areas of multi-year ice.

    If so, the next question is whether it is thin _enough_ to break up in storms like the recent ones, yes? And this is what you were really challenging in 213, yes? I.e, you question whether the ice is thin _enough_ to be “prone to rapid destruction by intense wave and wind action,” as per John in 209. John’s characterization of said ice as “very thin” is a matter of semantics, whereas the behavior of the ice under stress is an empirical question. If Wayne Davidson’s statement about satellite imagery showing lots of breakage in the new ice is accurate, then we have our answer.

    Comment by Kevin Stanley — 5 Dec 2007 @ 2:45 PM

  235. About GHG>ocean and solar>ocean forcing, I’ve some questions:

    - does an IR forcing and a SW forcing produce the same effect for ocean heat content ? (As IR doesn’t penetrate the water, but just warm the skin, we could imagine more IR radiation is used for evaporation at sea-air interface when compared to an equivalent SW forcing)

    - is there a strong influence of IR forcing water vapor feedback on SST (on Tropics) ? (As water vapor feedback is mainly effective in higher layers of troposphere, and as near surface layers are already almost saturated on VE absorption band, we could imagine the WV feedback have not a strong influence on STT and oean heat content, at least in tropical zone)

    Thanks for your answers.

    Comment by Charles Muller — 5 Dec 2007 @ 3:11 PM

  236. Jim, incidentally when I said in 233:

    In the Arctic the will mean frost steam and the fissures will rapidly refreeze — something which actually works in your favor.

    I meant of course the rapid release of heat by frost steam works in your favor — but not the rapid refreeze of the fissures. However, we will know soon enough. Just seeing how early spring returns to the Arctic should tell us a fair amount.

    Comment by Timothy Chase — 5 Dec 2007 @ 3:45 PM

  237. some info on sea ice from nsidc, and my thoughts (http://nsidc.org/seaice/intro.html):

    “generally, the top 100 to 150 meters (300 to 450 feet) of water must be cooled to the freezing temperature for ice to form.”

    -This is largely because as the surface water gets colder, it gets denser, and sinks away from the cold air. This is something that the ground in Ottawa (and elsewhere) doesn’t do.

    “multiyear ice: ice that has survived at least one melt season; it is typically 2 to 4 meters (6.6 to 13.1 feet) thick and thickens as more ice grows on its underside.”

    -So if the multiyear ice is typically 2 to 4 meters thick, it’s likely that ice less than two months old in the same general environment is less than 2 meters thick. How much less? I’m still learning. But there’s a lot of good info at NSIDC about the process. New ice starts as crystals here and there in the water, progresses to slush, and then gains rigidity over time. So it’s not like fresh water freezing on a still pond. Once (relatively) rigid it’s apparently still shot through with little droplets of high-salinity brine. So it seems to me that however thin or thick it is, it might also have less structural integrity than old ice. But as I say, I’m still learning.

    Comment by Kevin Stanley — 5 Dec 2007 @ 3:55 PM

  238. Just for the record, the data is in from NSIDC on average values of sea ice extent in the arctic for November. (OK OK it’s surface area not volume). 2006 data Oct 8.3 million sq kms, Nov 9.9. 2007 Oct 6.8 Nov 10.1. Paging Nick Barnes and Joe Duck. I will freely admit I did not expect that sort of dramatic turn around.

    Comment by Jim Cripwell — 5 Dec 2007 @ 4:30 PM

  239. RE # 237

    Kevin: you said

    [Once (relatively) rigid it’s apparently still shot through with little droplets of high-salinity brine. So it seems to me that however thin or thick it is, it might also have less structural integrity than old ice]

    That was another aspect of new ice I had not considered. And, it might add to explaination of how the ice surface diminished between Nov. 27 and Dec. 3 ( time in which cyclone(s) evidently swept into the Western Arctic).

    See the following images from Cryopshere Today.

    Dec. 4: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071204.jpg
    Nov. 27 http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071127.jpg

    Comment by John L. McCormick — 5 Dec 2007 @ 4:35 PM

  240. What is the ocean depth typically used to divide the surface waters from the deep ocean? Is it as much as 300 meters?

    Comment by David B. Benson — 5 Dec 2007 @ 5:14 PM

  241. ” I will freely admit I did not expect that sort of dramatic turn around. …” – JIm Cripwell

    You weren’t expecting winter?

    Will the perennial ice continue to get younger? I think that answer may be as important as extent.

    Comment by J.C.H. — 5 Dec 2007 @ 6:57 PM

  242. Timothy Chase 211

    It would appear that best estimates, the Holocene maximum was set roughly 7500 — prior to being shattered in the late twentieth century.

    Please see:

    Holocene climatic optimum
    http://en.wikipedia.org/wiki/Holocene_climatic_optimum?uselang=en

    If I remember correctly the data would seem to suggest that we are already above any temperature that has been reached in the past half-million years. And we are still climbing.

    PS

    Sources for the data off which the graph is based are given with the most recent being 2004.

    Shattered? Perhaps, if you hold your monitor upside down. Not only is the thick black line clearly 1C below the holocene maximum, but every single proxy was at one point higher than today. And, around 140 thousand years ago the Vostok and Epica ice cores “show” the Earth was at least 3C warmer than today.

    Also, you state in 165,

    Likewise, a hypothesis without so much as the suggestion of a means of testing it constitutes mere opinion. When it is used to rescue a theory without a means of independent verification, it is called an “ad hoc hypothesis.”

    With this in mind, could you please explain the independant lines of evidence for the amount of aerosals in the atmosphere from say 1940-1970.

    Comment by Ellis — 5 Dec 2007 @ 10:29 PM

  243. #237, Kevin, the problem with Polar orbiting NOAA shots is that they change every 40 minutes, one picture may show myriad of leads, the other clouds,

    then try on a regular basis, especially in the afternoon :

    http://www.weatheroffice.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg

    I saved one picture but RC doesn’t allow pic displays.
    There is no fixed link. Great stuff in #223 by John, water didn’t only reappear over the Arctic Ocean , important areas of open water resurfaced around Cornwallis Island after an intense blizzard as well.

    Comment by wayne davidson — 5 Dec 2007 @ 10:30 PM

  244. Re #238: Jim, if you look around the NSIDC site for the relevant material you’ll find that scientists expected it. The Arctic Ocean will need to warm up a fair amount more before it will be able to resist ice formation through the months of little or no sunlight. It’s a pretty standard denialist ploy these last few years of sharply lower summer ice to make claims that winter re-formation of the ice is somehow unexpected and then to try to make hay when things go as predicted. Don’t fall for it.

    Comment by Steve Bloom — 5 Dec 2007 @ 11:19 PM

  245. Ellis (#242) wrote:

    Shattered? Perhaps, if you hold your monitor upside down. Not only is the thick black line clearly 1C below the holocene maximum, but every single proxy was at one point higher than today. And, around 140 thousand years ago the Vostok and Epica ice cores “show” the Earth was at least 3C warmer than today.

    No. Shattered – at least within the Holocene. The past 10,000+ years. Longer than human civilization has been around. If you read the text, the colored lines represent local temperatures. The black line is the average of these — a “proxy” for the global temperature. The black arrow up at the top left? It says 2004. I believe that’s us, more or less. Shattered.

    However, you are right about the past half million years, more or less – qualitatively speaking, at least. I shouldn’t have said “If I remember correctly…” because clearly I didn’t. Judging from sediments, there appear to have been two times in the past 2.5 million years when temperatures were higher. What you point to 140,000 years ago was one of them. Another was 400,000.

    Both times, the two locations would seem to have been virtually in sync. Other times when one was especially high they were slightly out of sync, enough that it would appear that the global average was still below what it is today.

    Polar amplification implies that however much they were above present temperatures for those locations, you would want to divide that by two to come up with the extent to which the global temperature was above the current global temperature. So globally we are looking at more like 1.5 C above where we are now — and even if we stopped CO2 emissions today, temperatures would continue to rise for several decades. But CO2 emissions have actually been considerably higher since 2000 than they were during the 1990s.

    *

    For sediments as well as estimated temperatures of both, check the following:

    http://www.globalwarmingart.com/wiki/Image:Five_Myr_Climate_Change_Rev_png

    *

    Ellis quotes me from 165:

    Likewise, a hypothesis without so much as the suggestion of a means of testing it constitutes mere opinion. When it is used to rescue a theory without a means of independent verification, it is called an “ad hoc hypothesis.”

    Ellis (#242) wrote:

    With this in mind, could you please explain the independent lines of evidence for the amount of aerosals in the atmosphere from say 1940-1970.

    We are talking about sulfates and sulfides, mostly. Nitrates, too. Some organic carbon.

    For sulfates, you might check:

    Anthropogenic signals recorded in an ice core from Eclipse Icefield, Yukon Territory, Canada
    Kaplan Yalcin and Cameron P. Wake
    Geophysical Research Letters, VOL. 28, NO. 23, PAGES 4487-4490, DECEMBER 1, 2001

    Sulfate trends in a Col du Dôme (French Alps) ice core: A record of anthropogenic sulfate levels in the European midtroposphere over the twentieth century
    Journal of Geophysical Research, VOL. 106, NO. D23, PAGES 31,991–32,004, 2001

    … and if you want more sources or more information on how they try to estimate the levels and forcings for aerosols, you might try:

    Air Pollution as a Climate Forcing: A Workshop
    Day 2 Presentations
    What Relevant Information is Provided by GAW Stations, Ice Cores?
    Urs Baltensperger
    http://www.giss.nasa.gov/meetings/pollution2002/d2_baltensperger.html

    … but remember that it is current only as of 2002.

    Comment by Timothy Chase — 6 Dec 2007 @ 1:12 AM

  246. Re: 188 Martin Vermeer. Thanks for the reference. Just looked at the abstract but it looks like GCM modelling. I guess what I am getting at is that Lindzen and now Spencer are having to do really complex work with radars and satellites to try and determine the influence of rising sea temperature on cirrus clouds in the tropics. They suggest that the feedback is negative but nothing they do is conclusive. The obvious question is what conclusive proof do we have of the opposite – that the feedback is positive? Have people done the work with radar and satellites to prove that the feedback in the tropics is most likely positive?

    Re: 207 Timothy Chase. …But there is only one problem…
    I think you are saying that Spencer’s work is not conclusive. Fair enough but, as I said above, how have we proven that the converse is true? How have scientists proven that the effect of rising sea temperatures in the tropics on cirrus clouds is a positive feedback? I am hoping that it is not just an assumption made in the GCMs.

    Comment by Zelix — 6 Dec 2007 @ 4:46 AM

  247. Ellis, talking about the Holocene — last ten thousand years or so —look again at the picture you think you’re describing, you’re not seeing what’s right on the page there.

    Look at the left side. See the big black arrow labeled “2004″ there? Then look at the little inset square that expands the last few years. See the temperature?

    http://en.wikipedia.org/wiki/Image:Holocene_Temperature_Variations.png

    You’ve fallen into a mistake often made looking at these very long time series charts — recent years are too narrow and steep a line to tell from the frame around the picture.

    The recent — fast — temperature change is shown up to 2004. But only on the inset, it’s just a vertical line at the side of the frame on the long time series picture. Compare the position of that arrow — that’s the current end of the ‘big black line’ you claim to be comparing across eight thousand years.

    Seriously, look, slowly, carefully, at the chart there.

    How does that line from the movie go? “Who’re you going to believe, the chart or your lying eyes?”

    Comment by Hank Roberts — 6 Dec 2007 @ 4:53 AM

  248. Ellis, make sure you look back at the edits on that Wikipedia page, it appears someone’s been mucking with it. I didn’t review all the changes but just comparing it to William Connolley’s last text, for example, someone over the last handful of edits for example changed:

    WC: “Of 140 sites across the western Arctic, there is clear evidence for warmer-than-present conditions at 120 sites.”

    to this current nonsense word salad line:

    “At 140 sites across the western Arctic, there is clear evidence for warmer-than-present conditions at 120 sites.”

    When someone who can’t write gets into Wikipedia, this happens.

    Comment by Hank Roberts — 6 Dec 2007 @ 5:01 AM

  249. Oh, wait, I went to bed hours ago, I’m sleepwriting. I got the Wikipedia edits backwards. Well, I was right about the chart temperature for 2004. Memo to self, preview is for a reason …

    Comment by Hank Roberts — 6 Dec 2007 @ 5:03 AM

  250. Jim Cripwell @ 238: Just for the record, the data is in from NSIDC on average values of sea ice extent in the arctic for November. (OK OK it’s surface area not volume). 2006 data Oct 8.3 million sq kms, Nov 9.9. 2007 Oct 6.8 Nov 10.1. Paging Nick Barnes and Joe Duck. I will freely admit I did not expect that sort of dramatic turn around.

    I did.
    http://www.realclimate.org/index.php/archives/2007/10/sweatin-the-mediterranean-heat/#comment-62656
    http://www.realclimate.org/index.php/archives/2007/10/the-certainty-of-uncertainty/#comment-62937
    http://www.realclimate.org/index.php/archives/2007/11/did-we-call-it-or-what/#comment-66076

    CT measures area, not extent, which accounts for the slightly different timing of the rapid freeze.

    Comment by Nick Barnes — 6 Dec 2007 @ 5:20 AM

  251. Ellis @ 242: Shattered? Perhaps, if you hold your monitor upside down. Not only is the thick black line clearly 1C below the holocene maximum

    See where there’s an arrow pointing to the left-hand axis (at about 0.4) with the large label “2004″? That’s where the thick black line would be now if the scale permitted it.

    The inset graph helps to make this clear.

    Comment by Nick Barnes — 6 Dec 2007 @ 5:23 AM

  252. “Ray of hope: Can the sun save us from global warming?” (5.12.2007)
    http://news.independent.co.uk/sci_tech/article3223603.ece

    “Could the Sun’s inactivity save us from global warming? David Whitehouse explains why solar disempower may be the key to combating climate change”

    Any thoughts?

    Comment by Bee Coombes — 6 Dec 2007 @ 6:18 AM

  253. Ref 241. I am a Canadian. Of course I expect winter. What we dont know is what SORT of a winter we are going to get. I did not expect that it would be apparent so quickly that the “tipping point” of so little ice in the Arctic Ocean, was probably not a “tipping point” at all. Will it be so cold in the arctic this season that there is, say, 1 million sq kms more of ice than the 1979/2000 average next March?

    Comment by Jim Cripwell — 6 Dec 2007 @ 7:18 AM

  254. We just recently added our signature to the Kyoto protocol here in the land of Oz. It needed a change of government but it was FINALLY ratified. That just leaves one other country..hmmm, who could that be? In Australia cutting emmisions is no trifling economic task. We depend on agriculture, mining and other exports and these alone make up 20%+ of our greenhouse emissions. Cutting emissions will hurt us but it’s a pain we will have to get collectively used to. I phoned origin energy, one of our energy companies to ask when they will be rolling out sliver cell panels..they said not for another 3-5years. I called them ealier in the year and they said probably in less than 2 years..are we progressing or regressing?
    In response to some questions about the coherency or otherwise of scientific reports re: climate change. The use of satellite mapping is helping greatly quantify and qualify the extent of change seen in the world especially ice melt. i.e the ice melt observed by satellite in greenland this year was the fifth worse on record. Even though there has been quite a lot of re-freeze after the artic winter earlier in the year refrozen ice only refects 50-60% of the sun’s rays back into space compared with over 85% for hard-dry pack ice.
    It’s the difference between compacted snow-ideal! and just frozen water which will melt as soon as first rays of spring fall on it. What I read in ‘Science daily’ was that antartica ‘s west coast was having the first ever significant melt happening in 2005 and moulins appearing as far as 400kms inland and to an altitude of 500ft.

    Comment by Lawrence Coleman — 6 Dec 2007 @ 8:09 AM

  255. Ellis, while you are correct that Earth was warmer at the peak of the Holocene (by 6 billion people and dependent on a complex infrastructure. And yes it was ~3 K warmer 140 K years ago. Did you happen to notice on the same graph where ice coverage was?

    As to aerosols, a partial issue can be found here:

    http://earthobservatory.nasa.gov/Study/GISSTemperature/giss_temperature4.html

    You know, you could look this stuff up yourself, too.

    Comment by Ray Ladbury — 6 Dec 2007 @ 9:13 AM

  256. Re #252 “I did not expect that it would be apparent so quickly that the “tipping point” of so little ice in the Arctic Ocean, was probably not a “tipping point” at all.”

    This only seems to be “apparent” to you. It was predicted on this site that the anomaly, measured by surface area of ice, would quickly decline as winter approached. Whether a “tipping point” has been reached will become evident over the next few years, but the fact that extensive freezing of the ocean surface has occurred is, so far as I am aware, not a surprise to anyone (i.e. it should have been, and indeed was, expected, whether a tipping point has been passed or not). Can you cite any statements from those believing a tipping point has happened or may have happened which suggest otherwise?

    Comment by Nick Gotts — 6 Dec 2007 @ 9:20 AM

  257. Jim Cripwell @252: Will it be so cold in the arctic this season that there is, say, 1 million sq kms more of ice than the 1979/2000 average next March?

    No. Next question?

    For reference, the 1979/2000 average maximum sea ice area is a little over 14 million square kilometres. The anomaly in 2007, 2006, and 2005 was around a (negative) million square kilometres. The anomaly in 2004 was a little closer to zero. Before that there were 3 or 4 years of maxima around the long-term average. According to my reading of the “tale of the tape”, we haven’t had a maximum well above the long-term average since 1985, and we’ve never had a maximum as high as you suggest.

    What sorts of odds would you like? I’ll give you 5:1.

    How about one euro per twenty thousand square kilometres either side of the 1979/2000 average maximum sea ice area? To sweeten it, I’ll pay out 2:1.
    So if we see a maximum which is 500,000 square kilometres above the average, I’ll pay you 50 euros, but if the maximum is 500,000 square kilometres below the average, you’ll pay me 25 euros.

    (I have a side-bet with an office mate that you won’t accept this bet).

    Comment by Nick Barnes — 6 Dec 2007 @ 9:29 AM

  258. Ray,

    The sulfur graph at your link is impressive:
    http://earthobservatory.nasa.gov/Study/GISSTemperature/giss_temperature4.html

    It shows the modern sulfur level is lower than it was in 1900! Is this much reduction in aerosols (reduced over 3x from the 1970s peak) in the climate models?

    Comment by Steve Reynolds — 6 Dec 2007 @ 9:53 AM

  259. RE #253

    Jim, you said

    [I did not expect that it would be apparent so quickly that the “tipping point” of so little ice in the Arctic Ocean, was probably not a “tipping point” at all. Will it be so cold in the arctic this season that there is, say, 1 million sq kms more of ice than the 1979/2000 average next March?]

    You seem to be missing the real point of this discussion. It is not about extent. It is about the area of new ice and the diminishing perennial sea ice. Perennial sea ice—which is at least 10 feet thick and remains throught the seasons and through the years—dropped 14 percent from 2004 to 2005.

    If you think this winter refreeze is a signal there is as you said [probably not a "tipping point at all] you discount the dynamics of the ease of new ice melting in the summer.

    All betting aside, there is observed evidence the new ice on the Western boundary is being affected by wave and wind action NOW. (see the links at # 239)

    Dec. 4: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071204.jpg
    Nov. 27 http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/ARCHIVE/20071127.jpg

    How long that weather impact might be continued and repeated throughout the winter is an unknown. What is known is the melt season is just around the corner and it will begin with conditions that could hasten the melt and possibly the extent. Forget the surface area talk and focus on thickness.

    Comment by John L. McCormick — 6 Dec 2007 @ 10:07 AM

  260. ‘“tipping point” of so little ice in the Arctic Ocean, was probably not a “tipping point” at all. …’ – Jim Cripwell

    How is the winter so far in Ottawa? My brother owns a factory there. I reference winter in South Dakota, which is where we grew up. They appear to be having a balmy winter in the Dakotas. Could that be bad for perennial ice?

    Comment by J.C.H. — 6 Dec 2007 @ 10:53 AM

  261. Steve,
    I am not a climate modeller. However, I would imageine they are included (Note the link is from EOS/GISS). Wouldn’t you include them if you were doing the modeling?
    Sulfates vary on fairly short terms. A really big volcanic eruption causes a big spike but levels return to normal within a couple of years. It’s kind of amazing how well the graph follows economic activity for the period up to 1970.

    Comment by Ray Ladbury — 6 Dec 2007 @ 11:04 AM

  262. Zelix (#246) wrote:

    Re: 207 Timothy Chase. …But there is only one problem…
    I think you are saying that Spencer’s work is not conclusive. Fair enough but, as I said above, how have we proven that the converse is true? How have scientists proven that the effect of rising sea temperatures in the tropics on cirrus clouds is a positive feedback? I am hoping that it is not just an assumption made in the GCMs.

    In 207, I said that he is studying an oscillation — something dynamic — as a means of trying to determine what effects a higher temperature will have upon cloud formation once the climate system reaches equilibrium at that higher temperature — where the equilibrium is something static.

    I pointed out that this is roughly equivilent to trying to determine the sensitivity of the climate system’s temperature to solar insolation based upon the difference in temperature between day and night. It wouldn’t work. As such his approach provides us with no basis whatsoever for drawing the conclusion he draws.

    As for the GCMs, they don’t assume that clouds are a negative or positive feedback to temperature. They are built upon first principles, physics including radiation transfer theory, thermodynamics, fluid dynamics, etc., and then they crunch numbers. But they are models, and they do not include all the physical processes, and we know that in some cases they don’t model processes that well — which is a sign that there are some things which are missing — and generally gives us clues where to look so that we may improve their fit to reality.

    Comment by Timothy Chase — 6 Dec 2007 @ 11:53 AM

  263. Re #247: [Look at the left side. See the big black arrow labeled “2004″ there? Then look at the little inset square that expands the last few years. See the temperature?]

    You know, that graph would be a LOT clearer, at least to non-climate science professionals, if the X axis was flipped so that it followed the standard convention for time series and put the most recent values on the right side. As it is, my first impression was that it’s one of those “made up by denialists” fakes trying to claim that it’s really getting colder.

    Comment by James — 6 Dec 2007 @ 11:53 AM

  264. #246 Zelix: the positive cirrus feedback comes out of the modelling, which is IIUC based on known physics and ought to be valid.

    What you are apparently looking for is direct observational evidence for this feedback. Like the Spencer et al 2007 paper, but applied to global warming.

    The only way to btain such evidence would be to monitor cirrus formation in the tropics over a large number of years (using stable instrumentation and methodology) during which significant global warming is happening. A tall order, and I suspect the answer is no.

    Comment by Martin Vermeer — 6 Dec 2007 @ 12:39 PM

  265. J.C.H writes “How is the winter so far in Ottawa?” Looks like we are all set for an “old fashioned” winter. About 2 feet of snow so far; white Christmas looks good. Snow should keep too much frost from the tulips. The ski hills are all going full blast; I gather the New Zealand ski resorts refer to snow as “white gold”. Temperatures at or a little below normal. We have not had winter come so early for some years, and many of my friends keep hoping for the global warming!!!

    Comment by Jim Cripwell — 6 Dec 2007 @ 12:52 PM

  266. Jim Cripwell @ 265: maybe the precipitation you’re seeing is the result of evaporation from the exposed Arctic Ocean earlier in the year ….

    Comment by Nick Barnes — 6 Dec 2007 @ 1:44 PM

  267. Re # 229 Ray, you write “I’m afraid I am a bit of a skeptic “.

    Well, “Scepticism is the highest of duties” of every true scientist.

    About Ilya Usoskin, please visit his home page at http://cc.oulu.fi/~usoskin/ to see the remarkable amount of studies, e.g.

    Usoskin, Ilya G., and Gennady A. Kovaltsov, 2006. Cosmic ray induced ionization in the atmosphere: Full modeling and practical applications. J. Geophys. Res. – Atm., 111, D21206, doi:10.1029/2006JD007150, November 8, 2006, online http://cc.oulu.fi/~usoskin/personal/2006JD007150.pdf

    “…Results of the full Monte Carlo simulation are tabulated in a form of the ionization yield function. These tables are given together with a detailed recipe, which allows a user to compute easily the cosmic ray induced ionization for given location, altitude and the spectrum of cosmic rays. This provides a new tool for a quantitative study of the space weather influence upon the Earth’s environment. Some practical applications are discussed.”

    For comparison, please notice how badly climate modelers are able to present Solar radiation at TOA from Equator to Poles, e.g.

    Raschke, Ehrhard, 2005. How Well do we Compute the Insolation at TOA in Radiation Climatologies and in GCMs? GEWEX News Vol. 15, No 3, p. 1 and 15, August 2005, online http://www.gewex.org/Aug2005.pdf

    Further, about modelers’ problems please see

    Kiehl, Jeffrey T., 2007. Twentieth century climate model response and climate sensitivity. Geophys. Res. Lett., 34, L22710, doi:10.1029/2007GL031383, November 28, 2007

    “…It is found that the total anthropogenic forcing for a wide range of climate models differs by a factor of two and that the total forcing is inversely correlated to climate sensitivity. Much of the uncertainty in total anthropogenic forcing derives from a threefold range of uncertainty in the aerosol forcing used in the simulations.”

    Well, Kiehl almost openly admits that the modeling community has tuned the forcings to fit those to temperature variations, and Kielh doesn’t even mention clouds in the Abstract.

    Now, back to the Sun. Someone in this discussion has already mentioned my dear fiend Enric Palle, and I’d like to direct attention to the new study

    Goode, Philip R. and Enric Pallé, 2007. Shortwave forcing of the Earth’s climate: Modern and historical variations in the Sun’s irradiance and the Earth’s reflectance. Journal of Atmospheric and Solar-Terrestrial Physics Vol. 69, No 13, pp. 1556-1568, September 2007

    Abstract

    “Changes in the Earth’s radiation budget are driven by changes in the balance between the thermal emission from the top of the atmosphere and the net sunlight absorbed. The shortwave radiation entering the climate system depends on the Sun’s irradiance and the Earth’s reflectance. Often, studies replace the net sunlight by proxy measures of solar irradiance, which is an oversimplification used in efforts to probe the Sun’s role in past climate change. With new helioseismic data and new measures of the Earth’s reflectance, we can usefully separate and constrain the relative roles of the net sunlight’s two components, while probing the degree of their linkage. First, this is possible because helioseismic data provide the most precise measure ever of the solar cycle, which ultimately yields more profound physical limits on past irradiance variations. Since irradiance variations are apparently minimal, changes in the Earth’s climate that seem to be associated with changes in the level of solar activity—the Maunder Minimum and the Little Ice age for example—would then seem to be due to terrestrial responses to more subtle changes in the Sun’s spectrum of radiative output. This leads naturally to a linkage with terrestrial reflectance, the second component of the net sunlight, as the carrier of the terrestrial amplification of the Sun’s varying output. Much progress has also been made in determining this difficult to measure, and not-so-well-known quantity. We review our understanding of these two closely linked, fundamental drivers of climate.”

    Comment by Timo Hämeranta — 6 Dec 2007 @ 1:46 PM

  268. Ref 266 Touche (with an acute accent over the e)

    Comment by Jim Cripwell — 6 Dec 2007 @ 5:05 PM

  269. Ray Ladbury (#255) wrote:

    Ellis, while you are correct that Earth was warmer at the peak of the Holocene (by 6 billion people and dependent on a complex infrastructure. And yes it was ~3 K warmer 140 K years ago. Did you happen to notice on the same graph where ice coverage was?

    Two small points.

    The temperature 140,000 years ago was more like a little over 1.5 K above today’s temperature. He is grabbing his temperatures near the poles — which means polar amplification, roughly by a factor of 2, so you divide by 2 to come up with the difference in global temperatures between the two eras. And the Holocene at least extends back only to 11,500 Before Present.

    But yes, it was warmer. However, with a doubling at say 560 ppm we will probably be warmer than we were 140,000 BP once the climate system settles down to equilibrium — by about the same amount.

    Bye-bye Holocene, hello Anthropocene…

    Not quite the same ring to it, is there?

    Comment by Timothy Chase — 6 Dec 2007 @ 6:19 PM

  270. Ray Ladbury> Wouldn’t you include them if you were doing the modeling?

    Of course, and I’m sure aerosols are included at some level, but my question was whether the quantitative reduction in aerosols in the models matches what seems to be a radical 3x reduction since the 1970s.

    Comment by Steve Reynolds — 6 Dec 2007 @ 7:38 PM

  271. Re 258 Steve Reynolds

    The reduction in sulfates is indeed impressive. But note it represents conditions downwind of Canada and the US where emission have been reduced substantially. These reductions have been offset by vast increases in sulfates from China and India.

    Comment by B Buckner — 6 Dec 2007 @ 8:15 PM

  272. #81 Craig Allen: But this new crop [of leaders in Australia] includes some of the most committed, intelligent, environmentally savvy, socially progressive people in the country.

    Unfortunately, tenacious wasn’t on the list of attributes…

    From http://www.news.com.au/heraldsun/story/0,21985,22883548-662,00.html

    Kevin Rudd recoils from climate change pledge
    PRIME Minister Kevin Rudd last night did an about-face on deep cuts to greenhouse gas emissions, days after Australia’s delegation backed the plan at the climate talks in Bali.

    A government representative at the talks this week said Australia backed a 25-40 per cent cut on 1990 emission levels by 2020.

    But after warnings it would lead to huge rises in electricity prices, Mr Rudd said the Government would not support the target.

    Mr Rudd said he supported a longer-term greenhouse emissions cut of 60 per cent of 2000 levels by 2050

    Comment by matt — 6 Dec 2007 @ 8:49 PM

  273. Thanks to all for correcting my lying eyes, except of course Ray, who agrees with my lying eyes. Silly me, I was comparing proxy to proxy and not proxy to thermometers. Boy do I have alot to learn about “science”.
    Ray, I am not sure that from the graph it is possible to ascertain where the ice coverage was, however, it is interesting that during the last interglacial, where, I guess, we can all agree that it was at least 3C warmer, that there was more ice volume than there is at present. Of course, that is only from eyeballing the graph, but doesn’t higher temperatures usually equal less ice?

    As an aside, Ray, I apologize for any inconvieniance that my questions may pose. I guess, rather naively, that in a society it was acceptable to ask questions of others with more knowledge than myself, to further my understanding of an issue. Just think, if I did not ask the question Steve Reynolds would never have known about your link to aerosols. On the other hand, you could probably just not respond, and thereby keep all of your knowledge to yourself.

    Anyways, now that I have direction, thanks to Ray and Timothy, I am off to learn about the vagaries of aerosols and their effects on climate.

    Comment by Ellis — 6 Dec 2007 @ 9:51 PM

  274. Ice report:

    http://alaskareport.com/news1207/do77862_sea_ice.htm

    Thickness and age:

    http://pafc.arh.noaa.gov/ice.php?img=ice

    Comment by J.C.H. — 6 Dec 2007 @ 10:24 PM

  275. The sun was in a period of very high activity for the last 100 years. (The solar large scale magnetic field increased by 2.3 times from about 1890 to around 1970. Solar activity was at its highest level in over 8000 years in the later part of the twentieth century.) Just by simple solar observation the solar period of high activity appears to be over. (See this comment for details concerning solar changes over the last 11,000 years.)

    http://www.realclimate.org/index.php/archives/2007/11/a-phenomenological-sequel/#comment-72532

    Summary:
    Solar changes over last 11000 years. 16% of the time in the last 11000 years the sun was in very low activity. 9% of the time the sun was in very high activity. (See paper link in comment for details.)

    How much of the 20th century warming (modulation of clouds, in addition to irradiation changes (TSI & UV)) was due to the high activity of the sun?

    What is the time lag for the solar change from high to low activity? How long until the climate changes due to the change for high to low solar activity are observable?

    Thoughts?

    Comment by William Astley — 6 Dec 2007 @ 10:52 PM

  276. Mr. Gavin Schmidt,
    I am here

    Could you please explain your quote,

    “Less sunlight reaching the surface counteracts the effect of warmer air temperatures, so evaporation does not change very much,” said Gavin Schmidt of GISS, a co-author of the paper. “Increased aerosols probably slowed the expected change in the hydrological cycle.”

    Within the context of the paper you co-authored, that states,

    The study uses the longest uninterrupted satellite record of aerosols in the lower atmosphere, a unique set of global estimates funded by NASA. Scientists at GISS created the Global Aerosol Climatology Project by extracting a clear aerosol signal from satellite measurements originally designed to observe clouds and weather systems that date back to 1978. The resulting data show large, short-lived spikes in global aerosols caused by major volcanic eruptions in 1982 and 1991, but a gradual decline since about 1990. By 2005, global aerosols had dropped as much as 20 percent from the relatively stable level between 1986 and 1991.

    Was your quote taken out of context? If not, could you please explain further this apparent contradiction.

    [Response: No contradiction. My statement concerned the long term trends in aerosols, while the GACP part of that release was discussing very recent changes. Aerosol concentrations are still higher than they were earlier in the century on a global basis. - gavin]

    Comment by Ellis — 6 Dec 2007 @ 10:54 PM

  277. Ellis, you pointed to this chart:

    http://en.wikipedia.org/wiki/Image:Holocene_Temperature_Variations.png

    What you claim to be seeing doesn’t match the chart.

    Comment by Hank Roberts — 6 Dec 2007 @ 10:55 PM

  278. Ellis (#272) wrote:

    Ray, I am not sure that from the graph it is possible to ascertain where the ice coverage was, however, it is interesting that during the last interglacial, where, I guess, we can all agree that it was at least 3C warmer, that there was more ice volume than there is at present. Of course, that is only from eyeballing the graph, but doesn’t higher temperatures usually equal less ice?

    It was a little over 1.5 K above current temperatures 140,000 years ago. Polar amplification means you have to divide by 2 — since you are taking your measurements from Greenland and Antarctica — although this is of course an approximation.

    Please see:

    “Polar amplification” usually refers to greater climate change near the pole compared to the rest of the hemisphere or globe in response to a change in global climate forcing, such as the concentration of greenhouse gases (GHGs) or solar output (see e.g. Moritz et al 2002). Polar amplification is thought to result primarily from positive feedbacks from the retreat of ice and snow. There are a host of other lesser reasons that are associated with the atmospheric temperature profile at the poles, temperature dependence of global feedbacks, moisture transport, etc. Observations and models indicate that the equilibrium temperature change poleward of 70N or 70S can be a factor of two or more greater than the global average.

    2 January 2006
    Polar Amplification
    by Cecilia Bitz
    http://www.realclimate.org/index.php/archives/2006/01/polar-amplification/

    However, lets say 2 for the sake of simplicity. That means that if we double pre-industrial by going to 560, our new equilibrium will be about 0.7 K above about 140,000 years ago — since we are already at 0.8 K above pre-industrial. In any case, corrections are always appreciated. (As are references, no doubt.) It gives everyone a chance to learn. Not that everyone will take advantage of this, necessarily.

    Comment by Timothy Chase — 6 Dec 2007 @ 11:04 PM

  279. Ellis (#272) wrote:

    Of course, that is only from eyeballing the graph, but doesn’t higher temperatures usually equal less ice?

    Actually there would seem to be a fair number of people out there that don’t really think so. Trends regarding glaciers in Greenland (a doubling in the rate of melt and a tripling of the icequakes in a single decade) get discounted sometimes — since they haven’t been going on for that long. Then there are those that will point to the fact that some glaciers are still growing — even though 90% are shrinking.

    However, if you at least want to see what happened to the ice by way of proxy, you can check the sea level relative to today:

    Image:Phanerozoic Sea Level.png
    http://en.wikipedia.org/wiki/Image:Phanerozoic_Sea_Level.png

    Comment by Timothy Chase — 7 Dec 2007 @ 12:03 AM

  280. I just recalled a chart that adds another piece to the puzzle in understanding the Holocene:

    FIGURE SPM-1. Changes in Greenhouse Gases from ice-Core and Modern Data
    http://www.greenfacts.org/nl/klimaatverandering-ar4/figtableboxes/figure-1.htm

    We seem to have been raising levels of CO2, methane, and nitrous oxide for the past 5,000 years, but nothing like what we have done in the past century. Makes sense since we were at roughly 280 ppm for CO2 at the beginning of the Industrial Revolution. In fact the minimum for ppm of CO2 was set around 7,500 BP (before present) at about 265 ppm.

    Comment by Timothy Chase — 7 Dec 2007 @ 1:15 AM

  281. Re 225, 239, 259: John, Wayne
    There seems to be a clear reason for the Arctic warming at the beginning of December. On 27-29 November a strong rossby wave was forming over Alaska, followed by a cut-off of the wave and a drift of the cut-off high over the arctic. This brought very warm air throughout the whole troposphere into the arctic. You can follow this event looking at any Northern Hemisphere 500 hPa charts. On 2 december, the 500 hPa level reached until about 5700 m, which is not very far from subtropical highs.

    In principal this process of cutting off rossby waves is not unusual. However, I do not know, how unusual such a strong wave with such high temperatures is for mid-winter. This is a question for meteorologists or would need a statistical analysis (e.g. maximum 500 hPa heights North of 70 deg. lat. in december from NCEP over the last 50 years). Of course, if there is a general rise in temperature, one would expect the temperature of cut-off highs to rise. It is much more difficult to estimate, if the chance of occurrence of this process in mid-winter would also rise. As difficult as any question of circulation changes…

    Comment by Urs Neu — 7 Dec 2007 @ 3:50 AM

  282. William Astley (#274) wrote:

    How much of the 20th century warming (modulation of clouds, in addition to irradiation changes (TSI & UV)) was due to the high activity of the sun?

    What is the time lag for the solar change from high to low activity? How long until the climate changes due to the change for high to low solar activity are observable?

    Responding to your last two substantive questions first, you’ve asked, “What is the time lag for the solar change from high to low activity? How long until the climate changes due to the change for high to low solar activity are observable?”

    If I may quote from a different paper by several authors, two of whom you may already be familiar with:

    Secondly, the best correlations are consistently obtained for a time lag of 10 years in the sense that solar data lead temperature data. – pg. 21

    Solar activity over the last 1150 years: does it correlate with climate?
    I.G. Usoskin, M. Schussler, S.K. Solanki and K. Mursula
    “Cool Stars, Stellar System and the Sun” The 13th Cambrige Workshop (Hamburg, Germany), Eds. F.Favata, G.A.J.Hussain, B.Battrick, ESA SP-560, 13-22, 2005

    Now in response to your first question, “How much of the 20th century warming (modulation of clouds, in addition to irradiation changes (TSI & UV)) was due to the high activity of the sun?”

    The authors conclude:

    Note that the most recent warming, since around 1975, has not been considered in the above correlations. During these last 30 years the solar total irradiance, solar UV irradiance and cosmic ray flux has not show any significant secular trend, so that at least this most recent warming episode must have another source. – pg. 22, ibid.

    (Hat-tip to John C.)

    Comment by Timothy Chase — 7 Dec 2007 @ 4:12 AM

  283. Re 282 Please see also

    Usoskin, Ilya G., M. Schüssler, Sami K. Solanki, and Kalevi Mursula, 2005. Solar activity, cosmic rays and Earth’s temperature: A millennium-scale comparison. J. Geophys. Res. – Space Physics, 110, A10102, doi:10.1029/2004JA010946, October 1, 2005, online http://cc.oulu.fi/~usoskin/personal/2004ja010964.pdf

    Comment by Timo Hämeranta — 7 Dec 2007 @ 7:21 AM

  284. Re 270
    The 3x reduction in sulphate refers to emissions from North America. (Greenland icecores) I guess the European reductions are more or less the same. Asian emissions on the other hand has increased over the same period.

    Comment by oyvinds — 7 Dec 2007 @ 7:42 AM

  285. Ellis, I also misread the chart-which really did a piss-poor job of conveying the info it was trying to convey. And asking questions is fine. What I have trouble with is the snide implication that the role of aerosols in the 1940-1970 period was in any way “ad hoc”. My admonition was to suggest that you could avoid such ignorant suggestions if you did a quick search and looked at reputable sources (e.g. NASA, NOAA, IPCC) rather than those from the denialosphere.

    Comment by Ray Ladbury — 7 Dec 2007 @ 8:05 AM

  286. William Astley, I’m curious. Just how would you get a delayed response to the types of mechanisms you are positing? And what other forcing would you suggest gets diminished (or negative forcing increased) to compensate for this effect? There is very little wiggle room in the CO2 forcing, so this would still mean that CO2 is the main driver of the current warming. No matter how much you dance around the subject, you will wind up at the same spot–anthropogenic CO2 emissions are driving current climate. That is a very robust conclusion.

    Comment by Ray Ladbury — 7 Dec 2007 @ 8:42 AM

  287. 276

    [Response: No contradiction. My statement concerned the long term trends in aerosols, while the GACP part of that release was discussing very recent changes. Aerosol concentrations are still higher than they were earlier in the century on a global basis. - gavin]

    Thank you for your response Gavin. I just have a couple of follow up questions, When you say earlier in the century do you mean the past hundred years? When you say aerosol concentrations are still higher are you refering to each constituant aerosal (eg. sulfate, nitrate) being higher or do you mean the sum of all aerosals are higher? And when you say higher than earlier in the century, does that mean higher than at any time in the last century?

    Having read this paper, I suppose that you use the downward sw solar radiation as evidence of the increased aerosal concentrations over the past 60 years, is this correct?
    If so, how does Gerald Stanhill’s comment,

    The cause of these large changes in Eg↓ is not known. The one most often suggested—changes in anthropogenic emissions of aerosols [Stanhill and Cohen, 2001]—presents a number of difficulties. First, the estimated negative shortwave forcing attributable to aerosol emissions is only one tenth of the
    measured reduction. Second, the recent widespread reversal of global dimming was measured at sites that have very low concentrations of anthropogenic aerosols as well as in areas such as China where such emissions are high and still increasing [Che et al.,2005]. Third, large changes in Eg↓ were found in the United States during the first half of the twentieth century, similar in size to those occurring in the second half, despite very different rates of aerosol emission [Stanhill and Cohen, 2005].

    effect this view of downward sw solar radiation as a metric for aerosals?

    [Response: I thought my statement was clear. But anyway.... aerosols concentrations are diagnosed directly through measurements of aerosol optical depth, not from solar radiation proxies. Further back, those estimates are sparser and so they are supplemented by ice cores measurements etc. Peaks of aerosol emission in the US and Europe probably occurred in the 1980s, though there is a big black carbon spike from the US in the 1920s-1930s. Overall aerosols have risen over the last century, but they may have stabilised and started to decrease in recent years. - gavin]

    Comment by Ellis — 7 Dec 2007 @ 6:37 PM

  288. In reply to Ray Ladbury:

    “And what other forcing would you suggest gets diminished (or negative forcing increased) to compensate for this effect? There is very little wiggle room in the CO2 forcing, so this would still mean that CO2 is the main driver of the current warming. No matter how much you dance around the subject, you will wind up at the same spot–anthropogenic CO2 emissions are driving current climate. That is a very robust conclusion.”

    Svensmark asserts that based on his research that an increase in solar modulation of cloud cover is responsible for 0.6C of the 0.7C of the 20th century warming. Other solar researchers have estimates of 75%.

    Ray, I agree that it does not seem possible that both groups of scientists can be correct. I do not support your comment, however that the scientific issues are settled.

    To me the research associated with the hypothesis, that solar magnetic field changes modulate the earth’s cloud cover seems to be real science.

    Can you or someone else in this forum, explain why this could not be possible?

    There are mechanisms for example, to explain how solar changes could modulate planetary cloud cover.

    http://www.realclimate.org/index.php/archives/2007/11/a-phenomenological-sequel/#comment-71835

    Palle’s research supports a reduction in planetary albedo (clouds) in the 20th century which would result in higher temperatures. As measuring planetary albedo is controversial, that explains why the scientific issue concerning solar modulation of cloud cover, is not settled.

    Earthshine
    http://solar.njit.edu/preprints/palle1266.pdf

    I see this RealClimate article (see link below) which asserts that Palle’s measurement of planetary albedo is incorrect. It should be noted however that the solar warming (calculated based on Palle’s albedo measurement) of 7.5 W/m^2 can be reduced and still allow solar changes to be responsible for the majority of the 20th century warming. (I believe the total calculate GWG warming is 1.5 W/m^2.)

    http://www.realclimate.org/index.php/archives/2006/02/cloudy-outlook-for-albedo

    Comment by William Astley — 7 Dec 2007 @ 7:39 PM

  289. William Astley (#288) wrote:

    Svensmark asserts that based on his research that an increase in solar modulation of cloud cover is responsible for 0.6C of the 0.7C of the 20th century warming. Other solar researchers have estimates of 75%.

    Svensmark has produced some really good correlations, hasn’t he?

    Here’s how:

    Other examples of unacceptable handling of observational data are presented by Svensmark and Friis-Christensen [1997] and Svensmark [1998].They, too, show a strikingly good agreement of solar and terrestrial data, in this case of the intensity of galactic cosmic radiation (representing solar activity) and total global cloud cover.Again,a close examination reveals a strange data selection.The agreement over a substantial part of the period investigated, i.e. over the last several years,has been obtained by employing data from the U.S. Defense Meteorological Satellite Program that actually do not represent total global cloud cover and therefore do not belong in the context of their analysis.An update with the correct data (from the International Satellite Cloud Climatology Program,ISCCP) shows that the development of total global cloud cover since 1992 has been in clear contradiction to the hypothesis proposed by the authors; …

    Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data
    Paul E. Damon, Peter Laut
    Eos,Vol. 85, No. 39, 28 September 2004
    http://stephenschneider.stanford.edu/Publications/PDF_Papers/DamonLaut2004.pdf

    … and it gets better.

    William Astley (#288) wrote:

    To me the research associated with the hypothesis, that solar magnetic field changes modulate the earth’s cloud cover seems to be real science.

    Can you or someone else in this forum, explain why this could not be possible?

    We have knowledge of how carbon dioxide and other greenhouse gases render the atmosphere increasingly opaque to thermal radiation as the levels of these gases increase. It comes down to spectra and radiation transfer theory, which is then explained in terms of photon absorption by molecules, quantum states of excitation and their relaxation by photon emission.

    Its physics, well-established physics. Whatever might get discovered won’t undo this. And there has been a great deal more discovered than just the physics which all adds up to a coherent scientific view of the world.

    *

    The sun’s magnetic field may have a non-negligible effect upon the earth’s climate. However, even if I set entirely aside my understanding of the physics involved, the fact that people such as Svensmark have to make recourse to such methods as are detailed in the paper given above tells me at least that such a model is no longer a credible alternative to our mainstream understanding of global warming.

    William Astley (#288) wrote:

    There are mechanisms for example, to explain how solar changes could modulate planetary cloud cover…

    Hypothesized mechanisms, but no solar trend to drive them. I pointed as much out in 282. Quoting from an earlier paper by two of the authors of one of the better papers you’ve cited — which it would appear wasn’t that good a paper. Try lining up their hypothesized Holocene era solar cycles with the Holocene Thermal Optima, the Medieval Warm Period and the Little Ice Age. And remember, the more sunspots, the hotter the sun.

    William Astley (#288) wrote:

    Palle’s research supports a reduction in planetary albedo (clouds) in the 20th century which would result in higher temperatures. As measuring planetary albedo is controversial, that explains why the scientific issue concerning solar modulation of cloud cover, is not settled.

    It isn’t measuring planetary albedo which is particularly controversial, it is how he chose to measure it — and the fact that far more extensive records provide far more reliable estimates.

    William Astley (#288) wrote:

    I see this RealClimate article (see link below) which asserts that Palle’s measurement of planetary albedo is incorrect. It should be noted however that the solar warming (calculated based on Palle’s albedo measurement) of 7.5 W/m^2 can be reduced and still allow solar changes to be responsible for the majority of the 20th century warming. (I believe the total calculate GWG warming is 1.5 W/m^2.)

    http://www.realclimate.org/index.php/archives/2006/02/cloudy-outlook-for-albedo

    Is the reduction in albedo the result of a non-existent solar trend? Or the result of falling aerosol levels? Or is it the result of falling aerosol levels and their indirect effects upon cloud formation – as aerosols are actually large enough for cloud-droplet nucleation?

    But more importantly, what is the net effect of the clouds? Cooling by means of their albedo effect or warming by means of their greenhouse effect? The cooling and warming effects are roughly equal in strength, with the net effect and even its sign depending upon the characteristics of the cloud.

    However, you would appear to be considering only the albedo, not the opacity to thermal radiation. Even if Palle’s highly inflated measurements of albedo had actually been right, it is quite possible that the net effect of diminishing clouds would have been to cool the earth due to diminished greenhouse effect rather than warm it due to diminished albedo.

    Svensmark might have certain strengths, but evidence and math clearly aren’t among them. Palle might too, but obviously these do not include math or logic. What is it about the views of such people that in contrast to mainstream science you find so compelling?

    Comment by Timothy Chase — 8 Dec 2007 @ 6:18 AM

  290. William Astley,
    You persist in the incorrect belief that global climate models are just a fit to account for the observed warming, and that if you just find some other large forcing, the whole problem will go away. The reality is that the forcings in the models are determined independently of current temperature trends. Different forcings have different uncertainties, and greenhouse gasses are among the best known. It is fine to look at other forcings, but in trying to use them to argue that greenhouse forcing is less significant, you are arguing against physics. And in positing GCR modulation, you are arguing against physics with a nonphysical alternative. There is no evidence that such a mechanism is operative. There is no model (i.e. hypothesis yielding quantitative predictions) that has been proposed. It is not clear that the proposed model would even yield the correct trend (unless you can figure out how to make it work during the day, but not at night. And even if we found that your suggested forcing was operative, it would not affect greenhouse forcing, but would most likely affect estimates some less certain forcing (aerosols, other cloud formation processes, etc.).
    You have spent a great deal of time learning about dubious forcings. I would suggest that you take a tiny fraction of that prodigious investment and learn a little bit about GCMs.

    Comment by Ray Ladbury — 8 Dec 2007 @ 8:49 AM

  291. William, with regard to Svensmark, I would suggest checking out:

    Pattern of Strange Errors Plagues Solar Activity and Terrestrial Climate Data
    Paul E. Damon, Peter Laut
    Eos,Vol. 85, No. 39, 28 September 2004
    http://stephenschneider.stanford.edu/Publications/PDF_Papers/DamonLaut2004.pdf

    It doesn’t deal exclusively with him, but it will give you a good indication of how he gets his correlations. I would also suggest keeping in mind the fact that clouds have both an greenhouse effect and an albedo effect. They warm as well as cool, and the two effects largely cancel one-another. And aerosols have what is called an “indirect effect” where they promote the formation of clouds by acting as nuclei for water droplet formation.

    *

    Finally, as Ray Ladbury points out, the trends in greenhouse gases, aerosols and solar irradiance which the models make use of are based upon empirical data independently of the models, and the formula which the models make use of are based on physics — not mere correlations.

    With regard to the opacity of greenhouse gases to thermal radiation, it comes down to their absorption spectra and distribution in the atmospheric column. The absorption spectra are are subject to precise measurements in laboratories and are well-understood in terms their excitation states and quantum mechanics.

    Their distribution in the atmospheric column is also well-known, although not as preciesly as their spectra. Likewise, we can measure the effect rather precisely throughout the atmospheric column at a large number of altitudes for each gas now that we have satellites capable of taking measurements on over 2000 different channels.

    *

    Nothing that we might discover regarding magnetic fields or the like will change what we already know by means of well-established science. And the models do a rather good job of fitting the observed behavior of the climate. The fact that they do so even though they are independent of such observed behavior suggests that the models work well.

    Likewise, the fact that they fit what we know regarding the paleoclimate suggests that they do well. And the fact that they do well both with regard to current and past climates suggests that whatever additional forcings might possibly be discovered will not be of central importance.

    Comment by Timothy Chase — 8 Dec 2007 @ 2:43 PM

  292. #281 Urs, Yes makes sense, there were strong upper winds, distinct wind and temperature laminas and strange irregular profiles. But it was all part of a slow warming starting at end of November.

    #252 Bee, Surely inactive compared to 2001-04 , but I am quite sure I’ve seen some sun spots during the last five months, will double check my archives…

    Comment by wayne davidson — 8 Dec 2007 @ 9:41 PM

  293. August 24-27 single spot near the sun’s equator… Will check September October on Monday…

    Comment by wayne davidson — 8 Dec 2007 @ 10:10 PM

  294. Re 292

    Check here: http://www.dxlc.com/solar/

    Comment by Phil. Felton — 9 Dec 2007 @ 9:24 AM

  295. #293 Phil, But of course there is SOHO. So much for “no sunspots for months” comment. There is something about the sun which drives people including scientists to speculate, its probably because its a big thing to understand. But the very recent record, the data of substance, indicates no Maunder minimum devoid of sunspots, at least for now.

    Comment by wayne davidson — 9 Dec 2007 @ 3:33 PM

  296. You can keep track of daily sunspot observations here.

    Comment by tamino — 9 Dec 2007 @ 3:58 PM

  297. Yet today denialaists take the snow carried from the steaming Arctic Ocean and falling in the middle of the ‘States as a sign that the AGW story is wrong… They’re delightedly holding a stick, yet it’s the elephant’s tail, eh!

    Comment by Nigel Williams — 9 Dec 2007 @ 11:35 PM

  298. Several posts refer magnetic indices and their use as proxy data for studies of solar influnence on terrestrial temperature. The index data set derived at the Finnish Meteorological Institute has been mentioned too. Here I would like to make a contribution to that thema.

    As a comment on geomagnetic activity indices (e.g., aa, ak etc) referred here (#105, 116, and 150) I would like to clarify some basic definitions. Geomagnetic activity indices are connected with the transient variations of the geomagnetic field usually in the time frame from a few hours to daily variations. Indices are discrete numbers connected with the maximum amplitude or deviation of the magnetic field in the time interval in question. All regular variations (both internal and external) have been removed from the magnetic data from which the indices have been derived. Thus, the time series of activity indices reflect the disturbed magnetic conditions in the Earth’s ionosphere and magnetosphere ultimately due to variations in solar activity.

    Activity indices are usually derived from the continuous magnetic recordings of permanent magnetic observatories. Indices calculated from data produced at a single observatory reflect magnetic activity conditions of regional scale. A set of observatories with global extension can be used for production of indices for global scale. Depending on which observatories have been used in the index derivation, different symbols have been attached on the activity values series. Usually three-hour index of a single observatory is labeled as K-index, and the daily index based on eight K-values is ak or Ak. On the planetary scale there are 3-hour Kp and daily Ap (see, e.g., http://www.gfz-potsdam.de/pb2/pb23/niemegk/kp_index/description.html)

    In studies of long-term geomagnetic variations (space climate), say from years to decades and more, activity index series give important data source. The longest available index series is called aa and it is based on two antipodal observatories in UK and Australia. The aa-series started in 1868 giving thus about 140 years of continuous magnetic information. The aa-index series have been utilized e.g. for determining long-term trend in the solar magnetic field stretched into the interplanetary space with the solar wind (e.g., Lockwood et al., 1999).

    The aa-series was extended by using magnetic data from Helsinki (Finland) observatory that covers the interval 1844-1897. The magnetic observations were compiled from the original notebooks and analyzed by the Magnetic unit of the Finnish Meteorological Institute (e.g., Nevanlinna 2004). This extended series is thus the longest one based on magnetic observations. The data is available here: http://www.ava.fmi.fi/MAGN/magn.

    Currently the Magnetic unit is dealing with historical observatory data from 5 observatories from the 19th century giving more confidence of the existence data series. Preliminary data are here: http://www.ava.fmi.fi/~hakkinen/pietari/

    In studies dealing with possible solar signatures in terrestrial temperatures, aa-index and its extension and other similar data series have been widely used as proxies of suspected solar fingerprint in the atmospheric temperature variations. There are certain inhomogeneties in the long-term index series like in aa , thus any correlation found between T and solar variation must be carefully checked with independent data series (if available).

    Comment by Heikki Nevanlinna — 11 Dec 2007 @ 9:56 AM

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