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Christy Crock #2: Jumping to Conclusions?

Posted on 10 April 2011 by grypo

Christy Crocks (200 x 70 pixels)During a Congressional hearing for U.S. House of Representatives Committee on Science Space and Technology, Dr. John Christy made the following statement:


"I think there's been too much jumping to conclusions about seeing something happening in the climate and saying 'well the only way that can happen is human effects"

But are scientists really jumping to conclusions?  Scientists are well aware that the recent climate events, or any climate events for that matter, can be caused by variability in the natural world.  It is well established that human emissions are not the only variable in forcing the climate to change.  For example, slow changes occur constantly due to orbital factors and the Earth's tilt; and faster changes occur due to natural cycles like the El Nino Southern Oscillation (ENSO), but the questions that this committee set out to answer were (i) whether or not humans are likely to have caused recent climate responses, and even more important, (ii) will humans likely cause further and more rapid changes to our global climate system.  If one looks at the conglomeration of evidence, it appears Christy in the minority with answering the former question and judging from other statements he has made, the same is true of the latter.  

In the IPCC AR4 WGI, the scientific consensus of the modeling work completed, concluded the following:

"Climate simulations are consistent in showing that the global mean warming observed since 1970 can only be reproduced when models are forced with combinations of external forcings that include anthropogenic forcings (Figure 9.5). This conclusion holds despite a variety of different anthropogenic forcings and processes being included in these models (e.g., Tett et al., 2002; Broccoli et al., 2003; Meehl et al., 2004; Knutson et al., 2006). In all cases, the response to forcing from well-mixed greenhouse gases dominates the anthropogenic warming in the model. No climate model using natural forcings alone has reproduced the observed global warming trend in the second half of the 20th century. Therefore, modelling studies suggest that late 20th-century warming is much more likely to be anthropogenic than natural in origin, a finding which is confirmed by studies relying on formal detection and attribution methods"

Even further, through the use of detection and attribution studies, the IPCC said:

"The detection of an anthropogenic signal is also robust to using different methods. For example, Bayesian detection analyses (Appendix 9.A.2) robustly detect anthropogenic influence on near-surface temperature changes (Smith et al., 2003; Schnur and Hasselmann, 2005; Min and Hense, 2006a,b). In these studies, Bayes Factors (ratios of posterior to prior odds) are used to assess evidence supporting competing hypotheses (Kass and Raftery, 1995; see Appendix 9.A.2). A Bayesian analysis of seven climate models (Schnur and Hasselman, 2005) and Bayesian analyses of MMD 20C3M simulations (Min and Hense, 2006a,b) find decisive evidence for the influence of anthropogenic forcings. Lee et al. (2005), using an approach suggested by Berliner et al. (2000), evaluate the evidence for the presence of the combined greenhouse gas and sulphate aerosol (GS) signal, estimated from CGCM1 and CGCM2 (Table 8.1; McAvaney et al., 2001), in observations for several five-decade windows, beginning with 1900 to 1949 and ending with 1950 to 1999."

Scientists have also documented the human fingerprint on the type of warming happening as being consistent with what would be expected by an increased greenhouse effect, not solar or internal heat exchange.  The "It's Not Us" argument becomes very unlikely when we look at observed diurnal temperature range, stratospheric temperature changetropopause heightupper atmosphere cooling and contractingocean heat content, and sea level pressure.

All of this has led to one of the main conclusions of the conservative consensus of the IPCC:

"Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations."

Dr. John Christy did not produce any work of significant merit or abundance, or highlight anyone else's, to refute these basic findings on multiple lines of evidence, through differing methodologies, of the human influence on the global temperature change.  It is unequivocal that the climate is changing and it very likely our own doing.  Because of this, we will likely harm ourselves.  Fortunately, the future consequences are very likely up to us.  These are statements of probability based on the best available human knowledge, and not a case of scientists jumping to conclusions, as Christy opines.

I'll end with a comment also said at the Congressional hearing:

"...[B]eware those who deride predictive science in its entirety, for they are also making a prediction:  that we have nothing to worry about. And above all, do not shoot the messenger, for this is the coward’s way out of openly and honestly confronting the problem."

-  Dr. Kerry A. Emanuel

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Comments 1 to 17:

  1. I'd like to know what explanation for the recent warming Christy endorses, and how much evidence supports it. Considering all the evidence behind AGW is not enough for him, I wonder how much evidence his theory has...
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  2. That comment by Dr. Emanuel certainly belongs in a list of memorable quotes. Isn't part of the goal of a theory to be able to predict future phenomena? I'd imagine it'd be more difficult with an inter-disciplinary study such as climate science, but from what I've been hearing/reading they've been constantly improving. You'd think a credible scientist would want help improve predictive accuracy by identifying and eliminating sources of error.
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  3. The pictures are imageshack. I can only see the frozen frog unless I log in there. Why so few note this? Am I doing something wrong? (moderators, feel free to delete this post if you see fit)
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    Moderator Response: [DB] Which browser are you using? They display fine with Firefox. [grypo] Thanks. I fixed this. I uploaded the pics to SkS server, which is what I'm supposed to do anyway. It should not be a problem in any browser, now.
  4. i see the images fine, no idea why you are seeing the frozen terror frog, maybe a bug with imageshack?
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  5. I was looking at my previous post and I realized that I might not have been entirely clear. I was referring to Dr. Christy, not Dr. Emanuel in the last sentence of my post.
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  6. Daniel Bailey: I'm using Firefox 3.6.16. I don't think it's the browser... Maybe the Brazilian IP? Grypo: Thanks.
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  7. Alexandre #1 - we'll address your question in Christy Crock #3. Stay tuned.
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  8. use the new firefox 4
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  9. re Alexandre#3 I have the same problem, and have had in a few other SkS pages. I am running Firefox 4 and 3.6 (on different computers) but it isn't that. Surely it is because the images have not been imported into SkS but are linked through to imageshack, which has this peculiar practice of not letting you see images unless your site domain is registered. It is very annoying! Presumably it could be solved by the editor importing the images into SkS rather than linking through to imageshack - perhaps a nuisance, but hopefully not difficult?
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    Moderator Response: [DB] This is being implemented as standard practice here. Hopefully future instances of this issue will then be rare.
  10. Thanks grypo for sorting the image problem - all is fine now!
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  11. My Firefox runs fine, so ... Many times on this site, I cited peer-reviewed scientific papers - arising after the publication of IV report - which said that some - important - natural factors have not been properly estimated - “assessing” the "force of nature. " For example, the last quoted - by me - scientific paper: Solar-forced shifts of the Southern Hemisphere Westerlies during the Holocene, Varma et al., 2011.: “... we propose that the role of the sun in modifying Southern Hemisphere tropospheric circulation patterns has probably been underestimated in model simulations of past climate change.” Sub-Milankovitch solar forcing of past climates: Mid and late Holocene perspectives, Helama et al., 2010.: “If neglected in climate models, this lag could cause an UNDERESTIMATION OF TWENTY-FIRST–CENTURY WARMING TRENDS.” How much? And do not dominate (comparison - CO2 RF) "this [natural] lag" (inestimable well - before) currently?
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  12. @11 The first paper. (Solar-forced shifts of the Southern Hemisphere Westerlies during the Holocene, Varma et al., 2011) is about the sun's effect on ocean, which in turn has an effect on Southern Hemisphere Westerly Winds, which has several forcing/feedback components. The conclusions of the paper are fairly benign and very inconclusive in regards to how this would effect models, or indirect effects of of TSI in the Southern Hemisphere on century-long time scales. The underestimated effects (if true) could be positive or negative. For the second paper, I cannot get accces to the full paper, but if there is sunspot activity that is yet to be realized, and has an influence on climate, the future warming will be worse than we thought, and estimated projections will need to be adjusted upward -- if I understand the abstract correctly. But this thread is more about what we know and what our confidence is in certain statements. Neither of these studies, had Christy used them in his testimony, would have made his'jumping to conclusions' any more valid. I'm not sure what your last question is. Can you restate it?
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  13. @grypo A well. The last sentence (in my comments) is really too "condensed”. You're right. The papers cited by me was only served as proof - the reasons for objection - that is too weak account of the pre-2007 models, the natural factors of climate change (what says Christy) - particularly lags - by feedback associated to solar activity. Accordingly of too restrictive - use of "off-topic" on this site (in my opinion unnecessary makes it more difficult discussion), "I'm scared" to answer the second part of your doubts. But oh well - who does not risk ... and I'll try to as short as possible. If there is a lag in climate response - to changes in the TSI (cited paper offers c. 100 years, Swingedouwet al., 2010. 40-50 years - regional NH), it already (not just the future - the same claim the authors, writing about the present time: “... not yet have manifested itself fully ...”) we already have to do - with much more than we thought - the present result of such “lags”. And yet recently we had the greatest solar grand maximum from thousands years. Solar activity – the past 1200 years Steinhilber and Beer, 2011.: “The 9300-year long composite of solar activity (Steinhilber et al., 2008) shows that during the past six decades the Sun has been in a state of high solar activity compared to the entire period of 9300 years.” “Lags” in the response of climate to changes in TSI know (better) only recently. The most - comprehensively - it describes the paper: The influence of the de Vries (∼200-year) solar cycle on climate variations: Results from the Central Asian Mountains and their global link, Raspopov et al. 2006.: “An appreciable delay in the climate response to the solar signal can occur (up to 150 years). In addition, the sign of the climate response can differ from the solar signal sign. The climate response to long-term solar activity variations (from 10s to 1000s years) manifests itself in different climatic parameters, such as temperature, precipitation and atmospheric and oceanic circulation.” Varma et al. writing that - really - we do not know how to: “Since the reduction in TSI is only 0.15%, the global cooling effect is small and additional feedbacks are required to induce a significant change in the westerlies.” - yet having a significant impact on the global circulation. Still too poorly we known mechanisms for this significant change is responsible. Mid- to Late Holocene climate change: an overview, Wanner et al., 2008: „On decadal to multi-century timescales, a worldwide coincidence between solar irradiance minima, tropical volcanic eruptions and decadal to multi-century scale cooling events was not found..” And about these doubts says Christy. Estimating a 10% impact on the Nature - the Sun; of the current warming can be affected by the error about which too little is known - “jumping to Conclusions” - that to make strategic decisions in politics and to the economy.
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    Moderator Response: [DB] The Wanner study you link does not support your position.
  14. @Moderator These sentences (with final conclusion) - definitely - yes: “At decadal to multi-century timescales, climate variability shows a complex picture with indications of a possible role for (i) rapid changes of the natural forcing factors such as solar activity fluctuations and/or large tropical volcanic eruptions; (ii) internal variability including ENSO and NAO; (iii) changes of the thermohaline circulation; (iv) complex feedback mechanisms between ocean, atmosphere, sea ice and vegetation.” Those sentences - certainly not definitive - no. “However, there is scant evidence either for the cyclicity of climate variations on this time scale, or for the large-scale synchroneity of abrupt events. There is evidence for ‘‘Bond events’’ in some NH records although their cyclicity is doubtful (they may or may not be analogous to Dansgaard–Oeschger events), and their origins obscure.” "obscure" - does not mean: non-existent ...
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    Moderator Response: [DB] "These sentences (with final conclusion) - definitely - yes" Umm, still no. I'm swamped with deadlines today, so if anyone else wants to help Arkadiusz on this one, feel free. If not, I will deal with it tomorrow.
  15. AS @13: Steinhilber and Beer 2011 do state that the sun has been in a state of high activity, but their own graph shows that it is not "the greatest solar maximum for thousands of years": (From Steinhilber and Beer, modified to easily compare levels of TSI) As can be seen, the total TSI has been higher than at any time in the last hundred years at least twice before in the preceding 1100 years, and has shown similar levels of activity to the modern era many times before. Modern solar activity is at the high end of the range, but not unusually so - and the claim that it is so is of AS's manufacture rather than any claim made in the paper from which he quotes. Worse for him, the paper from which this data comes (Steinhilber, Beer and Frohlick, 2009) concludes that:
    "Our estimated difference between the MM and the present is (0.9 ± 0.4) Wm-2. This is smaller by a factor of 2– 4 compared to records [Lean et al., 1995; Lean, 2000] that have been used in climate model studies. Although our result is similar to the values of other more recent reconstructions [e.g., Wang et al., 2005; Krivova et al., 2007;Tapping et al., 2007] (see Table 1), the derivations are based on completely different assumptions, e.g., both Wang et al. [2005] and Krivova et al. [2007] use either the total photospheric magnetic field or the sum of the open field calculated from flux transport models using sunspot numbers and the fields from the ephemeral regions for the longterm change and determine TSI assuming that the change depends on the magnetic field in the same way as for the 11-year cycle modulation. In our approach the long-term changes of TSI do not dependent directly on Br, but on the strength of the activity which is also well represented by Br."
    So, rather than evidence of the dominating influence of the sun, this paper is evidence that the sun is much less influential on climate than was believed during the preparations of the IPCC Third Assessment Report and Assessment Report 4.
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  16. I think AS@13 in his quote mining from Steinhilber and Beer, 2011 skipped a previous nugget of truth:
    "With the beginning of industrialization in the 18th century, the importance of solar and volcanic forcing decreased while the influence of the anthropogenic greenhouse effect due to fossil fuel burning began to increase and is currently playing the dominant role."
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  17. @Tom Curtis „... dominating influence of the sun ...” I do not say here, the dominant role of the Sun. I (as Christy) say that it is poorly understood and works through delays and too poorly understood feedbacks - it may be estimated wrong: being too big - as you want - but also too small ... The papers, I have cited, say that there is no simple and sufficiently well-known relations - TSI - changes in global temperature. Remember that revealed many solar cycles - can be their superposition. Remember for example the recent (2009) found the cycle c. 6 thousand. years and Holocene optimum. A propos Holocene Optimum - here there were several new papers - worth this topic returning to Sk.S. Steinhilber and Beer, 2011 said several times (outside think cited by MichaelM) that are supporters of the theory of the dominant - currently - the role of A. GHG. But it is precisely because of their sentence, cited by me - has special value. I can cite a similar view of another "hot" supporter of the theory of AGW - Lockwood's,: „... the current grand maximum has already lasted for an unusually long time ...” ... but - the references to these two papers, is not cited by me papers ..
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