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Climate Hustle

Is the sun causing global warming?

Posted on 18 August 2010 by John Russell

This post is the Basic version  (written by John Russell) of the skeptic argument "It's the sun".

Until about 1960,  measurements by scientists showed that the brightness and warmth of the sun, as seen from the Earth, was increasing. Over the same period temperature measurements of the air and sea showed that the Earth was gradually warming. It was not surprising therefore for most scientists to put two and two together and assume that it was the warming sun that was increasing the temperature of our planet.

However, between the 1960s and the present day the same solar measurements have shown that the energy from the sun is now decreasing. At the same time temperature measurements of the air and sea have shown that the Earth has continued to become warmer and warmer.  This proves that it cannot be the sun; something else must be causing the Earth's temperature to rise.

So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming.

Note: we're currently going through the process of writing plain English versions of all the rebuttals to skeptic arguments. It's a big task but many hands make light work. If you're interested in helping with this effort, please contact me.

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Comments 1 to 50 out of 51:

  1. Why did you use an 11 year average instead of a yearly average? That may be more clear. Based on sunspot activity http://en.wikipedia.org/wiki/Solar_cycle, the past 2 solar cycles have been extremely active (past 22 years, plus the past 4 have been stronger than normal). I'd be shocked if solar sunspot activity does not correlate to sun temperature emissions.
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    Response: The 11 year average is used to filter out the solar cycle. The yearly values are shown in the intermediate version, along with the 11 year average (see the link to "Its the sun" for the intermediate version
  2. Skeptic use three versions of this argument based on TSI, sunspots and cosmic rays respectively. I think you need to address all three.
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  3. A brief comment about known physical properties of greenhouse gasses might be pertinent.

    Eg: We know that gasses like CO2 absorb heat energy. This helps keep the earth warm. However, average temperatures are now increasing roughly in pace with greenhouse gasses in the atmosphere. This suggests that greenhouse gasses like CO2 are probably causing the temperature rise.

    No, I haven't joined the dark side of the force ;-)

    But I like the idea of a plain English project which can engage people in communicating clearly about a complex subject.
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  4. PS: especially if what is written is true.

    :-)
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  5. Solar irradiance cycle does correlate with sunspot activity - to miniscule value of 1w/m2. The past two solar cycles have been lower than the most active cycle - 50 years ago.

    According to the cosmic ray theory, popular five years ago, there should be a pronounced cooling period in progress. The exact opposite is reflected in the trend - the 12-month period June 2009 to May 2010 was the hottest in 130 years of record-keeping.

    Decent graphs are here (and cover the points raised fairly well):
    http://www.climate4you.com/Sun.htm

    Latest NOAA global assessment here:-

    http://tinyurl.com/2aqso2u
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  6. Picoallen. Sunspot numbers & TSI have been trending downwards for the last 30 years. According to all I've read, cosmic ray levels are inversely proportional to solar activity-i.e. as solar activity goes up Cosmic Rays reaching Earth decline. Again, according to all I've read, the recent decrease in solar activity should have led to an increase in Cosmic Rays reaching Earth which-in turn-should have caused levels of cloud cover to increase (thus increasing Earth's albedo-a negative feedback). Yet in spite of everything pointing towards a *cooling* trend for the last 30 years, we've seen a *warming* trend instead. I'm happy to countenance something *other* than GHG's as the cause, but only if sufficient proof can be provided to back this alternate explanation. Its this proof that has been very lacking over the course of the Global Warming "debate".
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  7. What is the connection between solar activity and river flow??

    I have come across a number of research papers that look at various locations (South America, Europe and China) that appear to correlate river flows with solar activity??

    Probably the most prominent is Pablo Mauas et al - "Long-Term solar activity influences on South American rivers" - 2010, which adds to a previous similar report, but there are others (can't remember report titles at this time).

    From what I can make out, the authors focus on the relationship and don't suggest it is an alternative to an AGW explanation.
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  8. To add to my earlier comment, this is from the abstract of the Pablo 2010 paper:

    "We obtained that,after eliminating the secular trends and
    smoothing out the solar cycle,there is a strong positive correlation between the residuals of both the
    Sunspot Number and the stream flows, as we obtained for the Parana´."

    Which I interpret as being that the global warming trends being removed, what they mean as being secular isn't explained in the abstract or full report.
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  9. John

    I know this is correct and agrees with a rather famous figure from Max Planck Inst but could you provide references for your data?

    Tony
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  10. Hey Marcus, I'm aware of all that. I'm just suggesting that all three need to be covered in one post because I've pointed people at the intermediate version of this post before and immediately had them come back at me with those other arguments, which I then had to hunt down refutations for. It would be handy to have it all explained succinctly in the one page is what I'm suggesting.
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  11. Yes it is.

    Integrate the area under the TSI curve and you will get an increasing accumulation of energy added to the biosphere. Constant elevated TSI above a baseline will give linear increase in energy accumulation.

    Throw in a few non-linear but small energy absorption processes such as ice melt and evaporation and possibly some positive feedbacks from CO2GHG, cooling aerosols and clouds and you might bump the temperature curve around a bit mid century but produce a roughly linear temperature rise for the last 80 years.
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  12. Should the sun be the primary driver of climate change, the atmosphere would heat throughout, from the ground to the thermosphere. However, we know that the stratosphere is cooling, and there is also evidence of cooling in the mesosphere-lower thermosphere, which is what enhanced greenhouse warming would cause.
    I will look up some references for these and add them later.
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  13. Stratospheric cooling:
    Ramaswamy, V., et al. (2001), Stratospheric temperature trends: Observations and model simulations, Rev. Geophys., 39(1), 71–122, doi:10.1029/1999RG000065.

    Mesosphere-Lower Thermosphere:
    She, C. Y. et al. (2009), Long-term variability in mesopause region temperatures over Fort Collins, Colorado (41°N, 105°W) based on lidar observations from 1990 through 2007, J. Atmos. Solar-Terr. Phys., 71, 1558-1564.

    See also:
    Roble, R. G., and R. E. Dickinson (1989), How will changes in carbon dioxide and methane modify the mean structure of the mesosphere and thermosphere? , Geophys. Res. Letters, 16, 1441–1444.
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  14. Here is a more comprehensive article on cooling of the mesosphere and thermosphere:
    Beig, G., et al., Review of mesospheric temperature trends, Rev. Geophys., 41(4), 1015, doi:10.1029/2002RG000121, 2003.

    These are not easy reading, but they represent the best scientific work to date that I am aware of.
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  15. Jasper Kirkby, a British experimental particle physicist currently with CERN, Switzerland presents a lecture in which cosmic rays show a strong correlation with global temperature over short and long time periods. He is currently involved in research on their effects on clouds at CERN.....


    Some of these reconstructions show clear associations with solar variability, which is recorded in the light radio-isotope archives that measure past variations of cosmic ray intensity. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established.

    http://cdsweb.cern.ch/record/1181073


    Jasper Kirkby is a British experimental particle physicist currently with CERN, Switzerland. He originated the idea for the Tau-Charm Factory, an accelerator now under construction as BEPC II in Beijing. He has led several large particle accelerator experiments at SPEAR; the Paul Scherrer Institute; and most recently, the CLOUD experiment at CERN.


    http://en.wikipedia.org/wiki/Jasper_Kirkby

    Results from CLOUD are expected soon.
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  16. So where's the stratospheric warming Ken? If, as you claim, the sun is solely responsible for the warming of the last 30-60 years, then we'd expect to see a warming *throughout* the atmosphere-yet instead the Stratosphere is cooling, whilst only the troposphere is accumulating heat. You can perform all the mathematical chicanery you want, but all the available evidence shows that both sunspot & TSI levels have been *falling* for the last 30 years, which would suggest a *decline* in the amount of heat accumulating in the biosphere. Yet instead we're seeing a bucking of that trend which is occuring with a strong linear correlation to the rise in CO2 levels in the atmosphere!
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  17. #15: cosmic rays again?

    "Estimated changes of solar irradiance on these time scales appear to be too small to account for the climate observations. This raises the question of whether cosmic rays may directly affect the climate,"

    That's a large leap, with little to support it. A couple of rebuttals follow.

    The new research shows that change in cloud cover over the Earth does not correlate to changes in cosmic ray intensity. Neither does it show increases and decreases during the sporadic bursts and decreases in the cosmic ray intensity which occur regularly.

    published the first comprehensive modeling of how the sun might indirectly thin cloud cover and thus warm the planet. It suggests that cosmic rays are not up to the task by two orders of magnitude.
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  18. muoncounter at 10:32 AM, the abstract for the "new research" from 2008 that you cite actually states :-
    "A decrease in the globally averaged low level cloud cover, deduced from the ISCCP infrared data, as the cosmic ray intensity decreased during the solar cycle 22 was observed by two groups. The groups went on to hypothesize that the decrease in ionization due to cosmic rays causes the decrease in cloud cover, thereby explaining a large part of the currently observed global warming. We have examined this hypothesis to look for evidence to corroborate it. None has been found and so our conclusions are to doubt it. From the absence of corroborative evidence, we estimate that less than 23%, at the 95% confidence level, of the 11 year cycle change in the globally averaged cloud cover observed in solar cycle 22 is due to the change in the rate of ionization from the solar modulation of cosmic rays."


    So 2 groups studied one solar cycle, cycle 22, and arrived at certain conclusions.
    The authors of the research cited rather than finding corroborative evidence for such conclusions being reached, ended up estimating that less than 23% of the change in the globally averaged cloud cover observed in solar cycle 22 was due to the change in the rate of ionization from the solar modulation of cosmic rays.

    Unless the abstract is wrongly worded it seems to me that the authors DO confirm that cosmic rays DO affect cloud cover, perhaps as much as 23% they claim at a 95% confidence level.

    That is hardly a rebuttal.
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  19. johnD@18

    The 23% level isn't a majority share of the forcings proposed in any possible new thinking and having watched the Kirkby video, it is clear that current warming is largely caused by GHGs.

    Also it would seem that until the CLOUD experiments are completed, it is unclear what impacts cosmic rays may have on cloud cover.
    I accept that Kirkby has credibility, however one can apply the skeptic view of 'follow the money'.
    That wouldn't be a good idea and unlike AGW skeptics/deniers I wouldn't suggest at all that Kirkbys research is suspect!
    Indeed quite the opposite, the important thing is to understand what is going on so that we can do something about it. In the mean time any policy has to be based on what is known today.

    In any possible new scenario GHG emissions would need to be cut and work done to cope with climate change (eg. sea defences etc.).
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  20. I see this post has generated a lot of excitement. I fear that amidst all that excitement, my smaller points have no chance of getting a fair hearing:(

    But I have to forge ahead anyway: for I am sure I am not the only one to notice something amiss with the order of clauses in "Until about 1960, measurements by scientists showed that the brightness and warmth of the sun, as seen from the Earth, was increasing."

    Now let's stop and think about this: which clause is REALLY modified by "until about 1960" in the above sentence? Setting aside for now all prior knowledge about the topic, consider instead what the most natural follow on question would really be for the sentence above. I claim it is, "then what did they show after 1960?"

    You see, what he really MEANT to say was, "Measurements by scientists showed that the brightness and warmth of the sun, as seen from the Earth, was increasing, until about 1960."

    Now with this order, the sentence is correct, but it feels clumsy with so many commas. So modify it yet again, this time marking what is truly parenthetical with parentheses, to get:
    "Measurements by scientists shows that the brightness and warmth of the sun (as seen from the Earth) was increasing until about 1960".

    But we can do even better. Remember the Strunk & White dictum that the active voice is always more vigorous than the passive, we can change again to:

    "Scientific measurements show that the brightness and warmth of the sun (as seen from the Earth) have been increasing until about 1960".


    Now on to the next: "It was not surprising therefore for most scientists to put two and two together and assume that it was the warming sun that was increasing the temperature of our planet."

    There is a problem here: if they are "putting two and two together", then they are NOT 'assuming'. They are making a logical conclusion based on the evidence. But this raises the question of what the author is really trying to claim here: is he trying to claim that even before 1960, greenhouse gases were a significant cause of warming, or is he trying to claim that prior to about 1960, warming really was primarily caused by something else, and now it is caused primarily by greenhouse gases?

    This ambiguity is problematic for a basic version, which must be direct and to the point. Nor can a basic version risk the damage of trying to do too much. So best to set aside the question of what caused warming before about 1960, and concentrate on showing that it is now primarily greenhouse gases.

    So now back to this sentence: it should read, "It was not surprising therefore for most scientists to put two and two together and conclude that it was the warming sun that was increasing the temperature of our planet."

    Finally, for the same reason, we could actually drop the final sentence. The point of the Basic Version was to refute the claim, "It's the sun". That is already achieved w/o the final sentence, whose logical connection to the preceding is unclear anyway (the author has not established anything about the physical properties mentioned).
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  21. muoncounter

    Very simple reply. CERN would not be spending huge amounts of money funding Kirkby unless they believed the research potentially highly fruitful.

    There is always a queue of environmentalist / scientists ready to debunk anything that contradicts their agenda. Kirkby's background is highly credible (more credible than any of the climate 'stars'). The science is not settled. It never is.

    Every day, another scientist tries to make a name from himself.

    ***

    A "galactic lens" has revealed that the Universe will probably expand forever.


    http://www.bbc.co.uk/news/science-environment-11030889
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  22. As a general question, why are so many "skeptic" comments here tinged with political overtones, or things unproven to do with human nature?

    Is Kirkby's work intriguing because it's teasing out new information, or because it offers the fond hope of embarrassing "environmentalists?"

    Why do the two general sorts of things so often appear together when "skeptics" present their case? Why are irrelevancies so connected with science?
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  23. No one has touched on the subject of solar winds and the solar coronal magnetic field strength as indicated by the aa geomagnetic index, and the relevance or otherwise of the doubling of the solar coronal magnetic field in the last 100 years, which correlates well with temperature increases.
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  24. JohnD, "relevance or otherwise." You captured the reason why you don't hear of it.
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  25. doug_bostrom at 09:34 AM, can you elaborate why you consider it not relevant.
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  26. doug_bostrom

    Kirkby's work counters the perspective that the sun has no part to play in global warming as put forward in this blog. The difference in qualifications and credibility between the two individuals is utterly vast.
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  27. Kirkby's work might do that, eric144, sounds as though you wish for it to be so. But what does Kirkby's work have to do with environmentalists? How are the two things connected in your mind? I ask you because you're the latest person to appear here apparently burdened with such a conflation.
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  28. Good luck to Kirkby - he might find something interesting. However, EVEN if GCR DO have a part to play in cloud formation, phenomenological studies would suggest the effect is weak and given the non-trend in GCR flux, it cant be responsible for current warming.
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  29. #22: "CERN would not be spending huge amounts of money funding Kirkby unless they believed the research potentially highly fruitful."

    Oh, I don't know how true that is. I've been in and around particle physics projects for the last 6+ years; projects get funded and take on a life of their own. The original CLOUD proposals date back to 2000.

    Here's an interesting comment on CERN's experiment vis a vis Svensmark:
    Bent Sørensen, an environmental physicist at Roskilde University Centre in Denmark, believes Svensmark's paper lacks real evidence. "It's an interesting proposal for research, which is why CERN will try to acquire the knowledge that is lacking, " says Sørensen, "but I feel there's a large gap between finding statistical correlations with some assumptions and having a causal correlation or even a physical correlation."

    Well, well; correlation isn't causality? And yet the deniersphere clings to Svensmark's hypothesis? Isn't that ironic...
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  30. #24: "the solar coronal magnetic field strength as indicated by the aa geomagnetic index, "

    Interesting. The aa index is clearly increasing [see figure 3 in the linked paper]. If you believe that aa is correlated with global temperature, then you must necessarily admit that the earth is in fact warming.

    But correlation? As the denialists always ask, what does that prove?
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  31. BTW, if this graph is correct, aa to temperature is not even that good of a correlation.

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  32. doug_bostrom at 10:13 AM on 20 August, 2010

    Kirkby's work shows that the science is not settled. I am conflating scientists and environmentalists because that is how the NASA/Hansen/Schmidt/Mann axis behaves. Even Pielke Jr and Hulme are committed environmentalists and they are supposed to be skeptics.

    "Well, well; correlation isn't causality? And yet the deniersphere clings to Svensmark's hypothesis? Isn't that ironic... "


    I'm sorry, what is a deniersphere ? Is it something little children play in ? That's what it sounds like to me. I'm glad I'm not a gamma minus. The CERN experiments are being done to explore the mechanism of cloud formation .

    scaddenp

    You are comparing sceptical science, a blog behind which there is no expertise, with a highly credible physicist like Kirkby. I would be surprised if there were any non sceptical, independent, individual physicists. Forgetting representative, political bodies.
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  33. Eric144,

    The problem with accepting Kirkby's work as factual is a simple one: it hasn't been replicated. Mann's work, by contrast, has been confirmed by repeated independent studies.

    I'd like to know why you find Kirkby more credible than any climatologist. My guess is he confirms your existing bias, but I'm willing to hear your argument.
    Stating that his work must be right as it gets funding from a big scientific organization is self-refuting, because the scientists you don't like (Mann, Hansen, Trenberth) also get funding from top scientific bodies. By your logic their work must also be correct.
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  34. muoncounter at 12:04 PM, the abstract for the paper you extracted the graph from begins:-

    "Near-Earth variations in the solar wind, measured by the geomagnetic aa index since 1868, are closely correlated with global temperature ( r = 0.96; P < 10-7)."

    However it then on focused on only the northern hemisphere whilst acknowledging that the differences between the temperatures and trends of both hemispheres.

    Regarding correlation, some correlation is obviously necessary before scientists can begin investigation for any physical link.

    I find the expectations of many punters here towards correlation perplexing.
    There seems to be a requirement for any proposed influence to show almost total correlation before it will be acknowledged as being even relevant.

    This would be appropriate if the weather or climate only responded to one forcing.
    However the weather is a result of a large number of different forces of varying magnitudes and origins that variously oppose or amplify other competing forces to give the weather of the day, or the season, as winter and summer demonstrate.
    At certain times one particular force will dominate, at other times others will. Only when all these forces are fully understood will the weather be able to be modeled successfully, but we are not there yet.

    Similarly with the climate, there are many processes that are far from being understood, clouds, and solar winds being just two such processes. So dismissing any such process just because the correlation is not total seems rather premature to me.
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  35. #34: "Near-Earth variations in the solar wind, measured by the geomagnetic aa index "

    If you want to compare temperatures to the solar wind, why not look to ACE SWEPAM for actual solar wind data?

    The solar wind is only one component in the very complicated interplanetary magnetic field. From spaceweather:
    "When Bz is south, that is, opposite Earth's magnetic field, the two fields link up," explains Christopher Russell, a Professor of Geophysics and Space Physics at UCLA. "You can then follow a field line from Earth directly into the solar wind" -- or from the solar wind to Earth. South-pointing Bz's open a door through which energy from the solar wind can reach Earth's atmosphere!

    "I find the expectations of many punters here towards correlation perplexing. There seems to be a requirement for any proposed influence to show almost total correlation before it will be acknowledged as being even relevant."

    No argument there, but on this site, it is usually the deniers who quote 'corrleation isn't causality' when presented with correlation between atmospheric CO2 and temperature or ice melt or any of the other things we talk about.
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  36. johnd - Correlation is not causation. I would in fact refer you to this enjoyable yet spurious example...

    Unless you can hypothesize a reasonable physical interaction (I've yet to see any) wherein solar magnetic strength or cosmic ray patterns actual affect global surface temperatures (and I believe that no such direct correlation or interaction has been shown), it's at best an interesting correlation without causation.

    Clouds and formation rates would probably be your best bet there, but current consensus appears to be that clouds (which show a slight inverse relationship to temperatures over the last 60 years) have only a weak effect on global temps.
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  37. eric - I pointed you the skepticsci page not because of the article itself but because it was a convenient pointer to the papers published about the subject. Kirkby may be right - but the point was, even if he IS right, it still doesnt help explain current climate. The papers on that article deal with limitations on any real world response to cloud formation from GCR. I am all for Kirkby doing his experiments though.

    Read the concluding remarks in McShane or Wyner? Several commentators have also pointed to a problem with their analysis already but lets wait to both paper and responses are published.

    Also, note proxies are hardly used to "predict" climate. You can check whether current best models can reproduce past proxy temperatures from proxy forcings but you would guess correctly that this is more useful to check for invalidation than anything else given the uncertainties. Climate prediction is based purely on physics.
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  38. KR at 13:18 PM, the data in your "spurious example" is rather suspect. Pirates, at least in SE Asia, would number rather many more than the graph indicates and numbers are probably rising, especially as each financial crisis cycles through the region.
    Of course theses days instead of a fully rigged and crewed sailing ship with cannons poking out on all sides, a couple of blokes in a speedboat with a war surplus firearm, and perhaps even some ammunition, can still make a good living from a low cost operation targeting other small boats,tug boats, smugglers, drug runners etc. Some small fishing villages are renown as pirate lairs that drug runners and smugglers try best to avoid. :-)
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  39. Eric144, do you really imagine that labeling Hansen and a myriad of his colleagues as "environmentalists" is a substitute for an argument, has any hope of effectively rebutting their scientific findings?

    The problem with your internal blending of science with politics is that politics has no explanatory power when it comes to figuring out how climate functions. Your political bent is entirely divorced from climate research, physics and the rest of science. What you say as an amateur politician talking about environmentalists on a blog has no descriptive power for understanding the natural world.

    You may of course make up anything you like with regard to politics, but if you're not careful you're likely to blurt out certain things that can be tested against physical facts. For instance, explanations of how climate works must necessarily be coherent with a vastly larger realm of scientific understanding. Hansen's scientific research fits coherently into an interconnected web of broader scientific knowledge. If you say "Hansen's research is wrong because he's concerned about the environment and says so," you're not only saying Hansen is incorrect while failing to describe why, you're claiming that many other things we know to be true of the natural world are also false, are supposed to somehow be obedient to your politics. By so doing you're not only failing to address Hansen's scientific research, you're making yourself look conspicuously ridiculous.

    If you're claiming science is wrong stick with talking about science, if you want to be taken seriously.
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  40. Eric 144:
    >CERN would not be spending huge amounts of money funding Kirkby unless they believed the research potentially highly fruitful.

    I think that you are imposing your own belief on what they do. It also has tinges of 'science has to be beneficial to humans' about it.

    CERN have spent huge amounts of money on the LHC without any certainty about what it will find. So it is hardly unusual to spend money on something that has a lot of uncertainties. In fact science would be dead if projects were only funded if their were guaranteed 'fruits' to be harvested.
    The CLOUD experiment is about clarifying the issue of how much influence, if at all, cosmic particles have on cloud formation.
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  41. Eric144:
    "There is always a queue of environmentalist / scientists ready to debunk anything that contradicts their agenda."

    Hardly. Skeptical Science page on the subject isn't much different to what Kirkby has presented:

    http://www.skepticalscience.com/cosmic-rays-and-global-warming.htm

    In fact the Krivova graph on the skeptical science page was used by Kirkby in his presentation. It shows that there are GHG influences on the modern climate that greatly change the climate.

    Kirkby may have personal opinions that are weighted in favour of his his specialism, however on a wider scale the scientific community are only interested whether cosmic particles have an influence and to what degree, that will be incorporated into current knowledge.

    Hence the funding for the CLOUD project is justified on the grounds of clarify an unknown.
    Ultimately Kirkby's opinion will not override the results, what ever they are.

    I think you need to keep some objectivity.
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  42. MattJ at 04:38 AM on 20 August, 2010

    Matt; thanks. You make some good points which I'll consider soon when I come to updating this basic argument. Valid criticism is always welcome -- particularly when it results in an even more effective rebuttal.
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  43. Eric144:
    Kirkby's work counters the perspective that the sun has no part to play in global warming as put forward in this blog.

    Wrong!
    The issue isn't whether the Sun has an influence or not, it is the extent or percentage that is under scrutiny.
    Isn't it a bit ironic that many skeptics et al, claim the system is to complex, yet often have a need for a simple answer that just eliminates CO2??
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  44. Eric144:
    "Kirkby's work shows that the science is not settled. I am conflating scientists and environmentalists because that is how the NASA/Hansen/Schmidt/Mann axis behaves."

    I think your language is riddled with politicisation.
    I hope you are open to a possible conclusion that you may be wrong as well as your current belief that you think you are correct. If you are really interested in the science, then an 'axis' is irrelevant.
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  45. It might be worth distinguishing in the article between direct and indirect solar influences.
    The article implies solar activity being direct insolation or sunlight.
    In that respect Eric is 'off topic', however from what I can make out Kirkby suggests an indirect solar influence which is not insolation related.

    Maybe the article should cross reference the cosmic ray article?
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  46. Sunspots don't tell all.
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  47. So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming.

    No credible science? So you're suggesting that this site isn't about credible science? Seeing as this page quite clearly states:

    The other consequence of the warming ocean is it means there is additional "warming in the pipeline". Even if CO2 emissions were to start falling now, we already face further global warming of about another half degree by the end of the 21st century (Meehl 2005).

    So even if the forcing was reduced, there'd be warming for potentially 90 years. Considering this page suggests that the temperature in the graph on this page also corresponds closely to SSTs, then the cooling trend around 1940-1950 doesn't correspond to the increasing solar activity.

    Seeing as the temperature fell or remained stable while solar activity increased between 1940 and 1960, and a reduction in CO2 now would see continued warming, it suggests that temperature doesn't directly correlate (temporally) to the forcing. It seems far more likely that the increase in solar activity of ~0.8 W/m^2 up to 1960 in that graph is the cause of recent temperature changes rather than the CO2 change since 1960 of 5.35*ln(390/317) = ~1.1 W/m^2 (i.e. they're of similar magnitude) due to the thermal inertia of the system.

    Perhaps you would also like to put things in perspective. From 1880 there's been a minimum ~0.5 W/m^2 increase in solar activity (~0.8 W/m^2 until 1960, then a decrease). In the same time there's been a change in CO2 of 5.35*ln(390/290) = ~1.6 W/m^2. According to the IPCC there was a change in CO2 between 1750 and 2005 of ~1.7 W/m^2 and a net change in anthropogenic forcing of ~1.6 W/m^2.

    How can solar variability be completely discounted, since the graph here suggests it's at least ~30 % of the change due to anthropogenic sources? How do you explain why the IPCC graph suggests ~0.1 W/m^2 due to solar irradiance when this graph suggests otherwise? Perhaps the IPCC doesn't consider it cherry picking, but ~0.1 W/m^2 doesn't show the full story even if it is an accurate delta between 1750 and 2005.

    Furthermore, what known physical properties of greenhouse gases are you referring to?

    When I think of physical properties, I think of this as an example. We see that the Stefan-Boltzman constant is considered to be known to a standard uncertainty of 4e-13 W/m^2 and relative standard uncertainty of 7e-6 (68 % confidence interval). For two standard deviations (95 % confidence interval) it would be an uncertainty of 8e-13 W/m^2 and relative uncertainty of 1.4e-5.

    I would have thought that the effect of CO2 is pretty important in climate science, Section 6.3.1 of this document says:

    IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included.

    So it used to be 4.37 W/m^2, which was revised to between 3.5 and 4.1 W/m^2, leading to the current 3.7 W/m^2, all of which are estimates as opposed to physical properties. These estimates have an uncertainty of 0.2 W/m^2 and relative uncertainty of 0.05 (with no mention of confidence interval). Interestingly, IPCC AR4 WG1 Section 2.3.1 suggests 3.7 W/m^2 +/- 10 % for a 90 % confidence interval, giving an uncertainty of 0.37 W/m^2 and relative uncertainty of 0.1, which could be considered worse than the TAR!

    I don't think they really compare as physical properties, and don't see how they can be considered to be known when they're estimated.
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  48. As it says at the top of the page "This post is the Basic version (written by John Russell) of the skeptic argument 'It's the sun'"

    The comments at that page number over 550 covering a period of 3 years. Is this page, and indeed the other Basic versions not in danger of rehashing old points?

    I mention this as the chances are that the points Kamilian brings up here and at other Basic pages may have been covered over the last few years at the relevant main page.

    Is the intention to have Basic, Intermediate, Advanced share the same set of comments or will each have their own? I've seen moderators note things as being Off-Topic so should they note things as being Off-Level?
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  49. The Ville

    You seem to be determined to find some excuse for disbarring Kirby's science. None of them valid.
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  50. Good grief, you have a really distorted view of what I have written Eric.

    What I have clearly stated is that you are the problem not the science!
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