RealClimate

Comments

RSS feed for comments on this post.

  1. I’m assuming then Dr. Dessler that you have seen this….

    http://www.drroyspencer.com/2010/12/the-dessler-cloud-feedback-paper-in-science-a-step-backward-for-climate-research/

    I especially like the conspiracy theories presented therein.

    What struck me about your findings is that even if there is a negative feedback short-term feedback it is probably so weak that it does not even come close to offsetting the radiative forcing from us increasing GHGs. Also, even those models with a strong short-term positive cloud feedback do not necessarily have a high EQS for doubling CO2.

    Comment by MapleLeaf — 9 Dec 2010 @ 2:38 PM

  2. Hi Andy,

    This is but another example of how climate scientists are being played by the denialists. You attempted to discuss the issue with Spencer as if he were only doing science. But he is not. He is doing science and politics, and he has no compunction about sandbagging you.

    There is no gain to you in trying to deal with people like Spencer and Lindzen as colleagues. They are not trustworthy.

    Comment by Eli Rabett — 9 Dec 2010 @ 2:56 PM

  3. I thought El Nino events were caused by the so-called “delayed oscillator” effect. And that the westerly wind busts that seem to trigger and event may be related to the MJO in some way. But the latter is just a hypothesis.

    If Spencer is so confident that clouds trigger ENSO:

    “Spencer: ENSO is caused by clouds. You cannot infer the response of clouds to surface temperature in such a situation.”

    Then why has Spencer been unable to demonstrate causality and present a detailed conceptual model, or at least demonstrate unequivocally that changes in clouds precede ENSO events. We have TRMM data since late 1997, surely we can use that? Not to mention the GOES and NOAA satellite data.

    I am not convinced by Spencer’s arguments. Clouds are a feedback arising from ENSO not a driver.

    This whole negative cloud feedback claim is beginning to sound like the much refuted claim that GCRs significantly modulate cloud amounts.

    Maybe Spencer can tell us when this negative feedback is alleged to have started operating, and what the current long-term warming trend would have been without the alleged negative feedback. If we believe Lindzen, the negative feedback should have started very shortly after global temperatures increased by +0.5 C in order for his fast-feedback sensitivity of +0.5 C to be met, that or temperature will have to increase beyond +0.5 C and then decline. In reality, we have now warmed by over +0.8 C (for 40% increases in CO2), and the rate of warming of global temperatures has remained largely unchanged since the eighties. In fact, it is warming faster now than it was between 1915 and 1945.

    Comment by MapleLeaf — 9 Dec 2010 @ 3:02 PM

  4. I agree with Eli @2.

    Spencer’s rant on his blog and his defamatory comments about Andy are way over the line.

    Comment by MapleLeaf — 9 Dec 2010 @ 3:04 PM

  5. Great work!

    We’ve long thought that the character of feedback from different types of clouds could be quite different. Have you considered stratifying your analysis by cloud type (based on, say, cloud-top temperature) to reduce the scatter of Fig. 2a?

    Comment by DrCloud — 9 Dec 2010 @ 3:05 PM

  6. This quote seems at odds with what you claim the conspiricists claim. “It doesn’t mean that “clouds cause El Nino”, as Dessler suggests we are claiming,”
    How do you counter the phase space argument (which to a radio engineer is fairly basic in the analysis of feedback interactions)

    [Response: Spencer is claiming that clouds are causing ENSO. It may not be clear in his blog posts, but read our correspondence and you will see that's what he is claiming. Lead-lag arguments are fine if you believe the temperature change is radiatively forced, but that is not the case for ENSO. Spencer also acknowledges that feedbacks can be observed in non-radiatively forced climate change (see his 2010 paper). That's why he's so determined to argue that ENSO is really radiatively forced. --Andrew]

    Comment by Sean — 9 Dec 2010 @ 3:07 PM

  7. If you can get me a copy of the time series data, I’ll run Granger causality tests on it.

    Comment by Barton Paul Levenson — 9 Dec 2010 @ 3:11 PM

  8. “But as you can see, I have not ignored it — I have dismissed it because I think it has no merit. That’s quite different.”

    Priceless!

    Reminds me of one of my favorite bits of movie dialogue — from Casablanca:
    UGARTI: “You despise me, don’t you Rick?”
    RICK (BOGART): “I suppose I would, if I gave you any thought.”

    Comment by robert davies — 9 Dec 2010 @ 3:14 PM

  9. But Eli,

    I don’t thnk Andy is getting played. He played Spencer straight, as he should, as Spencer is at least doing some real science, and then applying the smackdown here (e.g. the “In fact, Dr. Spencer had a press conference in Cancun — about my paper. I didn’t have a press conference about my paper. Draw your own conclusion.” bit).

    And this post does me a great service. While I hadn’t bought into the Spencer cause and effect argument, I hadn’t understood why his claims are probably wrong (at least until I ran across Lin et al.) Dessier’s email exchange is quite enlightening.

    Comment by BCC — 9 Dec 2010 @ 3:22 PM

  10. Andrew: Thanks for posting this, and thanks also for the link to your paper. (Those of us without employer-sponsored access to journals appreciate it.)

    As for the issue of “to engage the deniers or not”, I admit that my view on this has changed a lot over the years, and I’m increasingly of the opinion that it doesn’t matter. Ignore them, and at least some will simply make up things or pull stunts to garner attention (like Monckton crashing a meeting in Cancun the other day). Engage with them and they will relentlessly spin whatever is said or done.

    This is not to say that scientists should ignore the deniers’ fabrications about the science itself; there will always be a desperate need for the real experts to debunk that open hydrant of nonsense. But direct interaction with them seems (to me) to be a wash.

    Comment by Lou Grinzo — 9 Dec 2010 @ 3:39 PM

  11. Andrew, same old argument: when the Rahmstorf et al. 2007 Science paper came out we were accused of this being “political” because it coincided with the release of the IPCC report. When the Vermeer and Rahmstorf 2009 PNAS paper came out we were accused of this being “political” because it coincided with the Copenhagen climate summit. All this by people who should indeed know that the authors do not have control over the publication date and have typically submitted this to the journal many months earlier. Besides, anyone who thinks that a new scientific paper on cloud feedback or sea level will be noticed by and influence the negotiators at UNFCCC conferences does not have a very realistic appreciation of how these negotiations work and what the negotiators are actually concerned with during these two weeks.

    Comment by Stefan Rahmstorf — 9 Dec 2010 @ 3:45 PM

  12. Andrew Dessler:
    You quote Roy Spencer as stating that “ENSO is caused by clouds”. But this statement isn’t in the exchange of emails that you reference here, and Spencer states in his blog post that this “would be too simplistic and misleading of a statement”. Could you clarify please where this quote comes from?

    [Response: Our apologies. We assumed it was clear that this was short a paraphrase of the much longer chain of email exchanges linked to. This has now been made explicit. Thanks! --mike]

    Comment by Philip — 9 Dec 2010 @ 3:48 PM

  13. Completely unrelated: I find the funniest thing about Spencer’s website to be the following. I can tell whether or not the current month’s global temperature anomaly is low or high, from the UAH MSU satellite series, prior to the release of the data, based on how quickly Dr. Spencer posts the number on his website. If it’s a cold month, the results go up before the UAH data are released to the general public. If it’s a warm month, they go up some time afterward. My casual observation is that there’s about a week’s difference, on average, in when the number gets posted.

    Comment by Christopher Hogan — 9 Dec 2010 @ 4:02 PM

  14. BCC Real Climate is not the mainstream media ;) If Dr. Dessler does nothing else than this it will be as if he did nothing. People such as Lindzen and Spencer have to be shown a cost to their two faced behavior, and the first step is to stop treating them as honest colleagues.

    Comment by Eli Rabett — 9 Dec 2010 @ 4:49 PM

  15. Andrew Dessler:
    It struck me that one of key aspects of Spencer and Braswell’s 2010 paper was their use of phase space plots to estimate sensitivity using satellite measurements. I cannot find any particular criticism of this approach in your paper, although you do mention that “inferences of large negative feedbacks have also been criticized on methodological grounds”. However, my understanding is that the papers you cite in this respect are criticisms of Lindzen and Choi’s 2009 paper “On the determination of climate feedbacks from ERBE data”, which I understand have subsequently been answered by the same authors. Could you therefore provide some more detailed criticism of the approach used by Spencer and Braswell in their 2010 paper please?

    [Response: The paper I said had been criticized was Spencer's 2007 paper. His 2010 paper came out in mid-2010, so it is probably too new for published criticisms to have appeared. I think there's a lot of interesting stuff in Spencer's 2010 paper ... my main point with respect to it would be that it does not apply to my analysis because I'm using ENSO variations to infer the feedback. We understand ENSO well, and we know it is not caused by clouds. -Andrew]

    Comment by Philip — 9 Dec 2010 @ 4:58 PM

  16. Has anyone heard of the Cornwall Alliance before? I had not till yesterday. It is an organization of Evangelical Christians who claim that Environmentalist are doing the work of the Antichrist. This would not cause me too much concern normally except for two things:

    1. They appear to be well funded and have a wide reach.

    2. Roy Spencer appears in one of their videos.

    Comment by Trent1492 — 9 Dec 2010 @ 5:24 PM

  17. Thanks very much for the paper.

    Comment by Edward Greisch — 9 Dec 2010 @ 5:34 PM

  18. Stefan Rahmstorf@11

    Has any one done an analysis of paper releases and summits?
    That would be amusing.
    But I think Spencer should be intelligent enough to recognise a coincidence.
    From a political POV, a journalist might look out for papers being published in the middle of a summit and then suggest it wasn’t an accident, despite hundreds of other papers released throughout the year. Has Spencer joined the ranks of the journalists?

    Comment by The Ville — 9 Dec 2010 @ 5:54 PM

  19. I agree with Eli (#14)

    Comment by tamino — 9 Dec 2010 @ 5:57 PM

  20. Stating the obvious…If Spencer’s primary evidence for negative or no positive cloud feedback is his claim that changes in clouds is the primary cause of ENSO, which has no evidence to support it, then I would say positive cloud feedback is more robust.

    As far as Spencer’s blog goes, it’s merely red meat for ideologues. What does one expect from someone Rush Limbaugh refers to as his “official climatologist”?

    Comment by MarkB — 9 Dec 2010 @ 6:09 PM

  21. I admit to being a tad behind in reading the literature, but, even so, I find this weird:

    “Spencer is claiming that clouds are causing ENSO.”

    Does Dr. Spencer have a mechanism whereby clouds initiate the equatorial Kelvin wave that shuts off the upwelling? Or is it that he claims that clouds somehow control the timing of the cycle overall? Gotta say, this seems extremely far removed from main-stream thinking about ENSO controls.

    Comment by DrCloud — 9 Dec 2010 @ 6:27 PM

  22. > shorter

    Here’s the form to identify “shorter” paraphrases — an Internet tradition:

    ‘Shorter’ concept created by Daniel Davies and perfected by Elton Beard. We are aware of all Internet traditions.™

    Comment by Hank Roberts — 9 Dec 2010 @ 6:31 PM

  23. Spencer: ENSO is caused by clouds. You cannot infer the response of clouds to surface temperature in such a situation.

    Dessler: ENSO is not caused by clouds, but is driven by internal dynamics of the ocean-atmosphere system. Clouds may amplify the warming, and that’s the cloud feedback I’m trying to measure.

    Actually the position you claim as the “Dessler” position is rather similar to the “Spencer” position. It is unfair to summarise Spencer’s position as “ENSO is caused by clouds”.

    From Roy Spencer’s blog:

    “It doesn’t mean that “clouds cause El Nino”, as Dessler suggests we are claiming, which would be too simplistic and misleading of a statement. Clouds are complicated beasts, and climate researchers ignore that complexity at their peril.”

    Spencer pointed out that Dessler’s analysis excluded the causality pathway of changing cloud cover causing temperature change ()but not the reverse). He proposed an alternative phase space model to include both directions of causality. This is not the same as just saying “clouds cause ENSO”.

    Comment by phlogiston — 9 Dec 2010 @ 6:50 PM

  24. Forgive me if this is naive, but it seems that it does not matter whether ENSO is caused by clouds (Spencer) or ENSO is not caused by clouds (Dessler). Under either scenario, you would reach the conclusion from this study that more clouds = more warming. The next relevant question is whether global warming yields more clouds. If it does, then there is a positive feedback. For Spencer to be correct, not only would ENSO have to be caused by clouds, but also warming would have to reduce cloud cover. Is there any evidence to support the second of those contentions?

    Comment by BKsea — 9 Dec 2010 @ 6:58 PM

  25. Question.
    How does this model compare with the ISCCP results that show low-level clouds decreased during the 1980s and 1990s as temperatures rose?
    http://isccp.giss.nasa.gov/projects/flux.html
    This is just one of a many papers which detail decreasing cloud cover corresponding to temperature increases.
    http://www.ornl.gov/~webworks/cpr/pres/109147_.pdf
    Am I understanding correctly that these models predict that low level cloud cover will increase under conditions of increasing temperature?

    Comment by Dan H. — 9 Dec 2010 @ 7:09 PM

  26. If Lindzen and Spencer are correct, delta GCR => delta clouds => delta ENSO; Sun Spot Number varies inversely with GCR, so -delta SSN => delta clouds => delta ENSO.

    This causal chain should result in a correlation between SSN and ENSO.

    I downloaded monthly ENSO data from http://www.jisao.washington.edu/data/globalsstenso/ and SSN from http://www.woodfortrees.org/data/sidc-ssn/from:1850, applied a running 12 month average to each series, and calculated the correlation coefficient.
    My result – R^2 =0.0071, R=-0.084 The unsmoothed R^2 was 0.0033.

    Comment by Brian Dodge — 9 Dec 2010 @ 7:15 PM

  27. A positive feedback between clouds and surface temperature does NOT imply that (more clouds) -> (more warming). It implies that (cloud changes due to warming) -> (more warming).

    Comment by DrCloud — 9 Dec 2010 @ 7:22 PM

  28. Thanks for a nice summary and readable treatment of a very complex topic. However I’m confused about how to read the error range, which seems very large compared to the measurement. Is here any way to assign a specific value to the likelihood that the feedback is positive or negative?

    Comment by Joe Hunkins — 9 Dec 2010 @ 7:50 PM

  29. Andrew Dessler: Your email correspondence with Roy Spencer included the following discussion of ENSO: “First, people have been studying ENSO for decades and my sense is that the basic theory that it is caused by changes in surface winds driving changes in ocean circulation seems to be quite successful and explains almost all of the details of the observations (e.g. the evolution of thermocline depth).”

    The increase in trade wind strength associated with La Niña events decreases total cloud amount over the tropical Pacific east of the Pacific Warm Pool, which, of course, results in an increase in DSR.

    You continued, “Second, I did a quick back of the envelope calculation and in order to get 1°C of warming in a 50m column of water in one year you need about 7W per square meter of heating. That seems a bit high. And if the warming occurs in just a few months (which it can, then the required radiative heating would be correspondingly larger).”

    Pavlakis et al (2008), in part, write in their abstract, “A clear anti-correlation was found between the downward shortwave radiation anomaly (DSR-A) time-series, in the region 7° S–5° N 160° E-160° W located west of the Niño-3.4 region, and the Niño-3.4 index time-series. In this region where the highest in absolute value DSR anomalies are observed, the mean DSR anomaly values range from −45 Wm−2 during El Niño episodes to +40 Wm−2 during La Niña events.”

    An increase in DSR of 40W per square meter far exceeds your annual requirement of 7w per square meter from your back-of-the-envelope calculation. Link to Pavlakis et al:
    http://www.atmos-chem-phys-discuss.net/8/6697/2008/acpd-8-6697-2008-print.pdf

    Regards

    [Response: Sorry, not even close, and no cigar. You are ignoring the fact that to determine the effect of clouds on SST you can't take just the downward shortwave effect and ignore the cloud greenhouse effect. The cloud greenhouse effect nearly compensates at the top-of-atmosphere, but it works its way into the surface budget through warming the atmosphere. But take heart -- you are in good company in being confused about this. It was the basis of Ramanathan's confusion in his famously wrong "thermostat hypothesis." --raypierre]

    Comment by Bob Tisdale — 9 Dec 2010 @ 8:12 PM

  30. \but also warming would have to reduce cloud cover. Is there any evidence to support the second of those contentions?\

    I thought he claimed the opposite?
    Warming can be caused by less clouds and then it gives the impression of positive feedback even if the feedback is negative. But warming does not lead to less clouds. Isn’t that what he claims or did I read it all backwards?

    Comment by Alex — 9 Dec 2010 @ 8:36 PM

  31. Dr. Dessler, thanks for the direction to the e-mails. Really enjoyed reading them and experiencing two scientists bouncing their theoroms off of each other. Really nice to see science evolving before my eyes. Keep it up!

    Comment by DeNihilist — 9 Dec 2010 @ 8:40 PM

  32. Re: 24, by Brian Dodge: “If Lindzen and Spencer are correct …” This reminded me of something I keep forgetting. They cannot both be correct. Lindzen’s approach is actually quite similar to mine, so if you accept Spencer’s criticisms then Lindzen is wrong. If one accepts Lindzen, on the other hand, then one must reject Spencer’s argument that cause and effect are wrong. This is one puzzle you don’t hear much about from the skeptics.

    Comment by Andrew Dessler — 9 Dec 2010 @ 8:57 PM

  33. Joe Hunkins: Given that the value of zero falls between the one sigma and two sigma levels, the probability of it being positive is around 80%.

    phlogiston: Spencer is trying to change his story in his blog. If you read his
    paper and my correspondence with him, the key argument he’s making is that clouds are the underlying driving force behind ENSO. I’m arguing that it’s not clouds. Our positions are not the same. Of course clouds may play a role in amplifying the ENSO, which is what I’m measuring here.

    Dan H.: Unfortunately, the data I’m looking at only goes back to 2000, so I
    can’t compare with an earlier period. As far as cloud cover
    decreasing, I have not looked in detail about exactly how clouds are
    changing (e.g., height, fraction, optical depth, particle size). So I
    can’t say exactly what’s happening. But that’s a great question, and
    one that I’m working on now.

    Bob Tisdale: I fully admit my BOE calculation may be wrong.

    Comment by Andrew Dessler — 9 Dec 2010 @ 9:25 PM

  34. Dr. Dressler @ 32, is this not to be expected in a subject (clouds) that is not yet on the front main burner and many different hypothesis are bandied about?

    As Dr. Spencer said in one of the e-mails – {Anyway, welcome to the cloud feedback debate. I’m actually happy that your paper will help to bring
    more visibility to a problem that *I* believe is still far from solved.
    Goodluck!
    -­‐Roy}

    Comment by DeNihilist — 9 Dec 2010 @ 9:30 PM

  35. What strikes me about both Andy Dessler’s and Roy Spencer’s papers are the large uncertainties, and the susceptibility of the calculated values to the choice of time intervals (e.g., 3 months optimal for Spencer), altitude (sea surface vs mid troposphere), and the possibility of distortions introduced by measurement biases, including those involving reanalysis data.

    More important perhaps is the difficulty of drawing conclusions about long term climate feedbacks from short term responses to ENSO events, a difficulty acknowledged by both authors. The problems are manifold. El Nino warming, for example, entails a regional phenomenon characterized by unusually strong deep convection, and imposing the heat from a warming ocean on a previously unwarmed atmosphere, with clear implications for regional changes in relative humidity and cloud cover. Warming due to atmospheric perturbations from CO2 or other greenhouse gases (or cooling from aerosols) involves a more globally distributed imposition of heat from a warming atmosphere on a previously unwarmed ocean. Although long term feedbacks might converge to a common value in each case, there is no a priori reason why the short term responses need be the same, nor why they are informative about the long term feedbacks (Andy’s paper in fact makes a point about this and it is also acknowledged by Roy Spencer). It’s also not clear from Andy’s paper to what extent the estimated positive feedbacks, with all their variability, are partitioned between long wave and short wave effects. One might speculate that they might represent long wave OLR reductions from increases in some cloud types, offset perhaps to a greater or smaller extent by increased SW flux from an increased cloud albedo. We don’t know, but if that is the case, it probably differs from long term effects where evidence exists for positive cloud feedback derived in part from reductions in low cloud cover.

    For all these reasons, I wonder whether climate sensitivity assessments based on ENSO variations are a good way to ascertain climate sensitivity to CO2 increases over the course of years or decades.

    [Response: What Andrew gets, strictly speaking, is the feedback of clouds on ENSO. For the reasons you point out, there are reasons to doubt that this feedback can be extrapolated to warming caused by CO2 increase. Still, it's one more number you can throw into the pot of estimates of feedbacks. If one is going to estimate cloud feedbacks from ENSO, one ought to at least do it right, and I think Andrew has done this a lot more right than Roy has. We can go into the reasons in a future post. Note also that, as Andrew noted, documenting cloud feedbacks of this sort give you another way of checking the cloud parameterizations in models. Given the large error bars, though, it doesn't help us narrow the estimates of climate sensitivity much, especially at the high end. It is another nail in the coffin of the idea that climate sensitivity is low, since to get low climate sensitivity you need a strong negative cloud feedback, and that is definitively ruled out by the data, to the extent that you can extrapolate from ENSO to CO2. --raypierre]

    Comment by Fred Moolten — 9 Dec 2010 @ 9:59 PM

  36. As Dr. Spencer said in one of the e-mails – {Anyway, welcome to the cloud feedback debate. I’m actually happy that your paper will help to bring
    more visibility to a problem that *I* believe is still far from solved.
    Goodluck!
    - ‐Roy}

    How does this jive with his public statement that Dressler’s paper has set climate science back … ?

    Or his press conference at Cancun, denouncing it?

    Comment by dhogaza — 9 Dec 2010 @ 10:51 PM

  37. DeNihilist: Yes, in fast moving debates theories come and go quickly. My point was that skeptics attack me for using a particular methodology, but they give Lindzen a pass for using the same methodology — because he says what they want to hear, but I don’t.

    Fred Moolten: First, the long and shortwave components of the cloud feedback are plotted in Figs. 3b and c. Second, you are correct that the short-term feedbacks may differ from the long-term feedbacks. What I said in the last paragraph or two of my paper is that measuring the short-term feedbacks is the best we can do now. But while we cannot yet measure the long-term feedback, the fact that the models’ short-term feedback agrees with the observations gives me some confidence in the models’ long-term behavior.

    Comment by Andrew Dessler — 9 Dec 2010 @ 11:10 PM

  38. I think its pretty clear. Andy says that he thinks they disagree on the cause of ENSO. Andy says that he believes that ENSO is caused by changes in winds changing ocean currents. Andy does not believe that radiative forcings can cause ENSO (i.e. changes in clouds would be a radiative forcing “Third, I follow your argument in figure 4 of your paper. However, I don’t think this type of lead-lag argument works if the cause o ENSO is non-radiative”).

    From there, Andy states that he does believe that clouds have feedbacks in the ENSO:
    “I do agree that clouds are playing a role in amplifying ENSO, but that’s the cloud feedback and that’s what I’m trying to measure.”

    What was Spencer’s reply. Not that Andy was misunderstanding his point of view and that he also believes that ocean and wind currents and not a radiative forcing and is also interested the cloud feedback role in the context of those non-radiative changes.

    He doesn’t say that because it is untrue.

    He says they’ll have to disagree about ENSO.
    “While I agree with you on the MJO, I guess we will have to agree to disagree on ENSO for now.”

    If Spencer doesn’t believe that radiative (e.g. clouds) are causing ENSO, it should have been clear from the e-mails that is what Andy thinks he thinks, and Spencer should have corrected Andy’s belief in the e-mails rather than stating they will have to agree to disagree. If Spencer doesn’t believe that radiative forces (e.g. clouds) don’t play a major role in CREATING ENSO, then he should put together a blog about and explain his response to Andy in these e-mails.

    Comment by Peter — 9 Dec 2010 @ 11:35 PM

  39. El-Nino is definitely not caused by clouds (masking the evaporation heat source too much is very good for cooling the sea in the long run) , but El-Nino causes a net cloud increase. This may be observable quite uniquely during sunsets at great distances away from the equatorial Pacific. In a few more ENSO cycles
    I will be able to visually prove with a greater deal of confidence this very neat phenomena by repeating the number of strange “dry” clouds observations seen only during twilights. (scroll on my website to see evidence)…

    Comment by wayne Davidson — 10 Dec 2010 @ 2:17 AM

  40. You do not need cloud to cause ENSO to get the reverse causation Spencer invoque to invalidate the derivation of cloud feedback given in this new paper. Even if ENSO comes first, if the influence of ENSO on cloud cover is from something else that just the value of temperature increase due to ENSO (for example, the particular pattern of temperature driving stronger or weaker than normal winds, or other indirect effect that are caused by ENSO but not by a global GHG-like increase of downward LW, the reverse causation will be there. It does not mean that Spencer is right, but it means that ENSO is not caused by clouds is not the killer blow the author think it is…

    It is not clouds that are tricky beast, it’s finding causation path in complex systems that is a tricky problem…A problem that has not been solved either by Spencer nor in this paper, sorry…

    Comment by kai — 10 Dec 2010 @ 4:08 AM

  41. raypierre replied: “Sorry, not even close, and no cigar. You are ignoring the fact that to determine the effect of clouds on SST you can’t take just the downward shortwave effect and ignore the cloud greenhouse effect. The cloud greenhouse effect nearly compensates at the top-of-atmosphere, but it works its way into the surface budget through warming the atmosphere. But take heart — you are in good company in being confused about this. It was the basis of Ramanathan’s confusion in his famously wrong ‘thermostat hypothesis.’”

    Interesting. In a reply to my same comment over at WUWT, Andrew Dessler wrote, “Bob Tisdale: You’re probably right about that. I put that into the e-mail without spending much time thinking about it.”
    http://wattsupwiththat.com/2010/12/09/the-dessler-cloud-feedback-paper-in-science-a-step-backward-for-climate-research/#comment-547536

    Additionally, if memory serves me well, Pavlakis et al addressed your concerns in the paper linked above and in their earlier companion paper:
    http://www.atmos-chem-phys.org/7/2013/2007/acp-7-2013-2007.pdf

    [Response: As I said on WUWT, I have not really thought about this issue. The line you're considering is something I dashed off in an e-mail. I don't know everything about the climate, and on this issue I would definitely defer to Ray's expertise. -Andrew]

    Comment by Bob Tisdale — 10 Dec 2010 @ 5:07 AM

  42. #16

    There is a raving lunatic by the name of pete ridley, google him ,active 24 hours a day spreading disinformation , denies any link to the alliance but has quoted them on blogs and is a habitual lier , as some here may confirm..

    Comment by John Byatt — 10 Dec 2010 @ 5:10 AM

  43. Andrew Dessler:

    Thank you very much for your response to my comment #15, in which you pointed out that the paper you said had been criticized was Spencer et al’s 2007 paper.

    Nonetheless, the papers you cite regarding “inferences of large negative feedbacks have also been criticized on methodological grounds” do appear to criticise Lindzen and Choi’s 2009 paper rather than Spencer et al 2007. Spencer et al 2007 analyses satellite observations relating to tropical intraseasonal oscillations and finds unexpected variations in ice clouds similar to those described by Lindzen’s proposed iris effect. It does not state that ENSO is caused by clouds, as your response implies.

    Even if Spencer and Braswell 2010 is too new for published criticisms to have appeared (as you suggest), it does seem that the approach you use in your paper to calculate cloud feedbacks from observations (shown in your figure 2A) has already been criticised by their paper. They state:

    “The regression slopes in Figure 1 range from near-zero to 2.5 W m-2 K-1, depending upon the averaging period, and whether surface or tropospheric temperatures are used, which illustrates why satellite diagnoses of feedback have remained so uncertain. Since all explained variances are rather low, there is great uncertainty in the value of each slope.”

    I would be interested to hear your response to this criticism. For comparison, it would also be very useful to see the phase space plot corresponding to your figure 2A in which the dots are connected in time sequence, similar to Spencer and Braswell’s figure 3(a).

    [Response: I think you've identified the crux of my argument with Spencer. His 2010 paper argues that scientists have cause and effect wrong: that it is the clouds that are driving temperature fluctuations, so that you cannot identify a climate feedback. However, I am arguing that, because I'm using ENSO variations, we know the cause, and it's not clouds. I do not argue in my paper that Spencer's 2010 paper is wrong (although I think it is). I argue that it does not apply here.. -Andrew]

    Comment by Philip — 10 Dec 2010 @ 6:03 AM

  44. kai, I think it’s fair to describe indirect effects “that are caused by ENSO but not by a global GHG-like increase of downward LW” as simply “ENSO”. After all, the definition of “ENSO” in general use is very broad.

    Your argument for reverse causation doesn’t make sense. Adding extra links in the causality chain doesn’t change the direction of cause and effect.

    Comment by Didactylos — 10 Dec 2010 @ 6:14 AM

  45. To isolate a practice of science issue here, being 180 degrees wrong in the stage where you are starting to think about a problem, can often be a very good thing as it focuses thinking on the issues. Eli did this once in a discussion with Bob Grumbine, who knew a lot more about what was being discussed, but had never gone down the squirrelly rabett hole that Eli fell into, and, after correction, it brought up some interesting implications.

    Comment by Eli Rabett — 10 Dec 2010 @ 6:54 AM

  46. Another point, notice how what we have going here wrt Spencer is exactly what is going on with the neighboring post with O’Donnell, et al. News flash, climate scientists are being attacked and not defending themselves effectively

    Gavin and others really have to activate their Rolladexes and start calling reporters. The science issues will not interest them, but the personal interplay will. And, oh yes, the contrast between the wild accusations Spencer is throwing about in public and his attempt to behave in private are key issues for reporters. The work is “two faced” and don’t be shy in using it, as in “we are extremely disturbed by Roy Spencers two faced behavior in attacking Andrew Dessler, not only is Spencer wrong about the science, but his behavior makes it difficult for us to treat him as trustworthy”

    Finally, guys, your Captchas are impossibly hard to read, which is stopping people from commenting. That may be a feature, but who knows?

    Comment by Eli Rabett — 10 Dec 2010 @ 7:01 AM

  47. What I think is striking here is the difference between Spencer’s scientist and blogist personae. I have found that when one is actually telling the truth, one version of it suffices regardless of the audience. If you have to change what you are saying when addressing scientists versus what you say when addressing the ignorati, then I will not trust what you say to either. I wonder if Spencer realizes that he is damaging his scientific reputation. I wonder if he cares.

    Comment by Ray Ladbury — 10 Dec 2010 @ 7:03 AM

  48. Dr. Dessler,
    I am a lay person with a strong interest is both the science of climate change, and efforts to solve the problem. I just wanted to say that this post of yours is one of the best written, most factual, and highly professional effort to explain in understandable terms what an important paper does and does not say, and explain how the denialists (in this case Dr. Spencer) go to scientifically dubious and even unprofessional lengths to attempt to discredit genuine scientific research for political reasons. Keep up the good work and thank you again for this.

    Comment by Dennis — 10 Dec 2010 @ 8:28 AM

  49. Roy Spencer seems be saying (from his blog post):

    ENSO causes variations in clouds
    They in turn cause variations in temperature (which presumably feeds back on cloudiness?)

    whereas Andres Dessler is saying:

    ENSO causes variations in temperature
    This in turn causes variations in cloudiness (which feed back on temperature)

    It is not clear to me why Spencer’s hypothesis automatically means that the feedback from clouds on temperature is negative though?

    Comment by Bart Verheggen — 10 Dec 2010 @ 9:37 AM

  50. Didactylos, maybe I was not as clear as I could have:
    first, let’s define “cloud surface warming”, or CSW, as less cloud albedo and/or more cloud downward LW.
    now consider those two causation chains:

    ENSO->higher surface temperature->CSW ->even higher surface Temp->…

    This is the behavior assumed by Dessler, which show a feedback loop.

    ENSO->indirect cloud effect->CSW-> higher surface temp
    |
    -> higher surface temp

    Only the first hypothesis allows you to compute cloud feedback using ENSO forcing. The second one does not, as nothing says how higher surface temp will affect CSW. It is not possible to say if you do not know how much indirect could effect there is, i.e. if the change in cloud cover is caused only by ENSO surface T change….or by something else related to ENSO. I hope I was more clear, and that it is not enough to say ENSO change the clouds, clouds do not cause ENSO to be able to derive any usefull measure of cloud feedback in a non-ENSO context. The second description can include a feedback, it would relate the higher surf temp->CSW link….but the observation could be compatible with positive or negative feedback depending of the ENSO->indirect cloud effect->CSW causation strength.

    Comment by kai — 10 Dec 2010 @ 9:59 AM

  51. Andrew Dessler wrote: “… skeptics attack me for using a particular methodology, but they give Lindzen a pass for using the same methodology — because he says what they want to hear, but I don’t.”

    I’d just like to point out that anyone who does that is by definition NOT a “skeptic”; in fact they are the antithesis of a skeptic.

    As a point of discourse, I suggest that we stop dignifying dishonest and/or gullible denialists by calling them “skeptics”.

    Comment by SecularAnimist — 10 Dec 2010 @ 11:03 AM

  52. I agree, Secular Animist. The term “skeptic” gives people like Morano and Watts undeserved gravitas, and provides cover for the likes of Lindzen and Spencer- whose skepticism does not extend to their own work.

    Maybe someone more creative than I can come up with a better descriptor. “Denialist” or “Denier” say it, but are a little tired, and “Zombie” too pejorative.

    They have been the ones defining the terms, a classic high school debate strategy. Instead, how about something like… Climate fantasists? Oil soldiers? Climate For Dummies advocates? Those don’t ring that well, so I’d like to hear of better ones.

    Comment by Mike Roddy — 10 Dec 2010 @ 11:50 AM

  53. To Andy, Raypierre, and others:

    First, Andy, my apologies for overlooking the fact that your Fig. 3B,C included not only model data but also your own new data. As you note, the SW results, compared with the LW data, are closer to zero,and with larger error bars, so we can have less confidence in the direction and magnitude of the SW change.

    Regarding Roy Spencer’s results, I would be interested less in whether he reached the right or wrong conclusions (I think Andy’s data make a strong case that cloud feedback on ENSO is not strongly negative) than in understanding the strengths and weaknesses of his approach. In essence, he reasoned that in the absence of feedbacks, a Planck response yields a partiular slope for the regression of flux change back toward equilibrium as a function of temperature, while a positive feedback delays the response (yielding a reduced slope requiring a greater temperature change), and a negative feedback heightens the slope, so that a given W/m^2 response is associated with a smaller temperature change.

    Other than reservations about his choice of time points, altitude, dependence on correlation coefficients and the like, how useful is the approach in and of itself?

    Comment by Fred Moolten — 10 Dec 2010 @ 11:56 AM

  54. Bart says in 49:

    Roy Spencer seems be saying (from his blog post):

    ENSO causes variations in clouds
    They in turn cause variations in temperature (which presumably feeds back on cloudiness?)

    I don’t read what Spencer says that way at all. Indeed, on his blog he says this:

    But what if the warming was caused by fewer clouds, rather than the fewer clouds being caused by warming? In other words, what if previous researchers have simply mixed up cause and effect when estimating cloud feedback?

    He then goes on to say that he’s NOT saying that cloud changes cause ENSO.

    Andrew paraphrased Spencers statement as saying that clouds cause ENSO, and I’m hard put to tell the difference between that and what is quoted here – unless the surface warming to which Spencer refers is not ENSO related.

    Since Spencer has not elaborated on how ‘clouds cause the surface warming’ and ‘I’m not saying clouds cause ENSO’ are logically congruent, the rest of us will simply have to guess at what he does mean. It sure sounds to me like he’s saying ENSO is caused by clouds, despite later denials.

    For my own understanding, could someone please clarify whether the warming (el-ninos) cause more or fewer clouds? My assumption is that warmer water evaporates more and produces more clouds. Said clouds would raise the albedo from above, but trap more IR from below, and that we’re trying to figure out the net difference between the two. Spencer asks what if … the fewer clouds being caused by warming

    Is he referring to la-ninas inevitably following the el-ninos? Or is there a weather phenomenon common to ENSO that I simply don’t understand whereby cooler waters have more clouds?

    Captch says “anything surrial”. Got the AGW thing down, it does.

    Comment by David Miller — 10 Dec 2010 @ 12:27 PM

  55. > Captchas are impossibly hard to read

    Anyone who’s missed this: to request a new Captcha that _might_ be easier to read:

    Click the little “2 arrows” icon, top of the column of three icons — 2nd or 3rd one presented is almost always easier to read

    Comment by Hank Roberts — 10 Dec 2010 @ 12:29 PM

  56. Mike Roddy@52

    I thought Gavin preferred ‘contrarian’??

    Comment by The Ville — 10 Dec 2010 @ 1:29 PM

  57. FYI, Science has weighed in Roy’s accusation that the publication date was orchestrated. My e-mail correspondence with Dr. Smith confirms his assertion that his goal was to get this out before the AGU meeting.

    http://news.sciencemag.org/scienceinsider/2010/12/science-criticized-in-cancun-for.html

    Comment by Andrew Dessler — 10 Dec 2010 @ 1:32 PM

  58. Fred: I would not categorize Spencer’s 2010 paper as an approach; it’s more of an argument. Basically, he’s saying that if you don’t know what’s causing the temperature change, determining feedbacks is impossible. My argument with Roy is not over whether that’s correct, but over my contention that, with ENSO, we know what’s causing the temperature change. Spencer is not describing a new or different way to determine the feedback.

    Comment by Andrew Dessler — 10 Dec 2010 @ 1:37 PM

  59. Thanks again for more informative articles and comments. One question: Andrew Dessler wrote: “Clouds both reflect sunlight back to space and a trap infrared radiation and keep it from escaping the space.” Should this read “…and trap…escaping the atmosphere”?

    [Response: Fixed--thanks! -mike]

    Comment by One Anonymous Bloke — 10 Dec 2010 @ 1:47 PM

  60. Bloke: it should have been “to space” … although your edit would be correct. (Mike et al.: can you update that?)

    Comment by Andrew Dessler — 10 Dec 2010 @ 1:58 PM

  61. Ray Ladbury asked “I wonder if Spencer realizes that he is damaging his scientific reputation. I wonder if he cares.”

    He doesn’t realize and he doesn’t care because he and his compatriots (in particular Pielke Sr., Lindzen and others have never had to pay a price. They really need to get their noses rubbed in it.

    Comment by Eli Rabett — 10 Dec 2010 @ 2:03 PM

  62. Sorry still confused. Should it read “…escaping the space” not “…escaping the atmosphere”?

    reCapthca says “dizzatt invariably” if that’s any help :)

    Comment by One Anonymous Bloke — 10 Dec 2010 @ 2:06 PM

  63. Ok, got my reading ability working. Not confused anymore. Thank you.

    Comment by One Anonymous Bloke — 10 Dec 2010 @ 2:26 PM

  64. Another recent paper on cloud feedback:

    \The present iRAM results for cloud feedbacks in the east Pacific provide some support for the high end of current estimates of global climate sensitivit\

    Axel Lauer, Kevin Hamilton, Yuqing Wang, Vaughan T. J. Phillips, Ralf Bennartz. The Impact of Global Warming on Marine Boundary Layer Clouds over the Eastern Pacific—A Regional Model Study. Journal of Climate, 2010; 23 (21): 5844 DOI: 10.1175/2010JCLI3666.1

    Co-author Kevin Hamilton concludes: \If our model results prove to be representative of the real global climate, then climate is actually more sensitive to perturbations by greenhouse gases than current global models predict, and even the highest warming predictions would underestimate the real change we could see.\

    University press release here.

    Comment by Jesús R. — 10 Dec 2010 @ 2:30 PM

  65. Andy (58) – my interest was in Spencer’s specific method of regressing the SW/LW TOA flux changes against temperature to derive a slope that could be compared with the slope predicted from a Planck response without additional feedbacks. His assumptions and parameter choices aside, what is the value of this method? I’m more accustomed to data presented as a temperature response to a forcing, whereas this method evaluates a power (W/m^2) response to an imposed temperature change. One might expect concordant results, but if not, why?

    Comment by Fred Moolten — 10 Dec 2010 @ 2:40 PM

  66. Eli says, “He doesn’t realize and he doesn’t care because he and his compatriots (in particular Pielke Sr., Lindzen and others have never had to pay a price. They really need to get their noses rubbed in it.”

    Actually, Eli, I disagree. I think they’ve paid a tremendous price–in terms of understanding. As a scientist, the thing I care about is understanding my subject matter. I find it very frustrating when I don’t understand, and when the light finally dawns, it is a beautiful thing. The denialati don’t get this feeling anymore. I’m sure Lindzen was very excited when he thought the ERBE data was supporting his position and saving his beautiful Iris theory–or at least the spirit of it. And then his hopes are wrecked on the shoals of cruel reality. That may be one reason why Spencer, Peilke and Lindzen (and Curry for that matter) are turning more and more toward the adulation of the denialosphere and away from serious science. I would think they find this exile painful–even if it is self-imposed.

    Comment by Ray Ladbury — 10 Dec 2010 @ 2:42 PM

  67. I’m with Eli on this one. They never stopped playing since they started, so assuming good faith is a losing game. If you continue to be honest and don’t let it suck up too much energy, that’s about all you can do. It is so obvious that once the hacked emails were in the public domain, it was a full court continuous press on keeping the biased rollout cooking and no quarter would ever be given. Facts – they’re not interested. They just want to go on creating the impression that there is a vast conspiracy to conceal the truth; after all, that’s what they do and their measure of what it is to be human is based on themselves.

    Real scientists, on the other hand, believe logic and truth are likely to prevail. In the end, if they are successful, the deniers will have a lot to thank them for in ensuring the continuing of humanity’s survival in less challenging circumstances. But I doubt that will happen anytime soon.

    I agree that skeptic is absolutely wrong; true skeptics look at all the evidence and don’t toss out everything they disagree with. Contrarian will do, but even that is too respectful. People who are contrarian by nature don’t necessary create false assertions and continuously push for them in the face of every kind of evidence and elucidation, they just like to go against the mainstream. These guys are just fake skeptics, using a disguise to validate their disinformation.

    Comment by Susan Anderson — 10 Dec 2010 @ 2:55 PM

  68. I started with pseudo skeptics but decided on fake skeptics to get rid of the furreign sound. I like climate fantasists, but that is also inaccurate; a climate fantasist could just as easily be a doomer, depending on your POV.

    Liar, of course, would be the most accurate but we’re not allowed to be impolite. Propagandist is fairly good.

    Comment by Susan Anderson — 10 Dec 2010 @ 3:00 PM

  69. Andy,

    I found and downloaded your paper through the citation page of Held and Soden’s 2000 Annual Reviews paper about water vapor and global warming. It is a nice paper.

    On the cause-effect relation between cloud feedback and temperature change, I have a small suggestion that you could also check the delta R (cloud) as in your Figure 2 with the monthly temperature TENDENCY. The final temperature anomaly in the data must be the result of time-integration of total tendency, which is the sum of individual tendencies from different forcing and feedbacks. The inclusion of monthly temperature tendencies and their variation with the cloud and ENSO might unravel the cause-effect relation in a more convincing manner.

    Comment by Jianhua Lu — 10 Dec 2010 @ 3:44 PM

  70. Re 54 David Miller –

    It is a common mistake to assume warming causes more clouds (*except perhaps for one thing, see below) – warming increases the saturation water vapor mixing ratio; if relative humidities stay about the same (which as far as I’m aware seems to be the case globally, though regional shifts can and will occur as storm tracks shift, etc.), then the water vapor mixing ratio would approximately increase in proportion. Clouds form or evaporate depending on relative humidity. If it warms up and the water vapor concentration stays constant, relative humidities would drop and cloudiness would be reduced – and the tendency would be for reduced precipitation as well, hence water vapor would increase in the atmosphere until precipitation can remove it as rapidly as evaporation supplies it, and hence we get the water vapor feedback; equilibrium cloudiness could remain the same.

    But there are a bunch of complex things that could allow cloudiness to change in response to climate changes.

    1. The tropopause tends to rise. The mass (and even more so, the volume) of the troposphere increases with warming. If the fraction of air that is cloud stayed the same, cloud amount would increase from that alone *. If we define layers of air with fractional cloud coverage and assume the layers expand with the troposphere and overlap between layers remains the same, then cloud area would be constant but cloud height would increase; cloud tops would be colder and so LW flux to space would be reduced – a positive feedback. However, if we keep overlap among layers constant but keep layers the same thickness and add part of a new layer to fill the expansion of the troposphere, then cloud heights would still increase but the area would also increase (the added area visible from space would be in the lower troposphere, hence it would not increase the greenhouse effect much (more than the effect of the higher cloud tops would already have done) (low-level warm clouds can emit almost as much as the surface, and anyway they are ‘buried’ under more water vapor which partially hides their emissions anyway) but would increase SW (solar radiation) reflection.

    2. In addition to cloud height (and overlaps with other clouds, humidity), it matters where and when the clouds are. Clouds at night have no cooling effect; the cooling effect increases toward the tropics, toward midday, toward summer solstice. Clouds over snow and ice have less effect on albedo (or might even decrease albedo) than over forests and ocean. Clouds at the top of a low-level inversion can increase LW emission to space. Changes in circulation would affect where and when clouds form and decay.

    3,… (this was not a complete description)

    Comment by Patrick 027 — 10 Dec 2010 @ 4:39 PM

  71. It is a common mistake to assume warming causes more clouds (*except … I mean a mistake in the sense that it could be expected only from the tendency for water vapor to increase (implying relative humidity doesn’t change a lot or at least doesn’t decrease a lot).

    Comment by Patrick 027 — 10 Dec 2010 @ 4:44 PM

  72. David Miller,

    Later on Spencer writes:

    “El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures.”

    His alleged mix up of cause and effect seems to refer to how cloudiness and temperature relate, rather than it having to do with ENSO.

    Comment by Bart Verheggen — 10 Dec 2010 @ 5:01 PM

  73. @Jesús R. (#64) The paper be Axel Lauer et al gets a positive cloud feedback because fewer low level clouds form with warming. The Dessler paper gets a positive feedback by finding more clouds (what level?) with warming. Can someone give a concise exposition for the lay person of these two seemly contrasting results?

    Comment by Mike — 10 Dec 2010 @ 5:17 PM

  74. However, if we keep overlap among layers constant but keep layers the same thickness and add part of a new layer to fill the expansion of the troposphere, then cloud heights would still increase but the area would also increase (the added area visible from space would be in the lower troposphere, hence it would not increase the greenhouse effect much… Actually, that’s assuming each layer has the same fractional area as any other layer of same thickness and that the overlap is the same between every pair of layers – I don’t think either is actually true, certainly the first part is not (I get the impression cloud fractional area is largest for low-level and high-level clouds and smaller in between); thus, if we ‘add a new layer’ of cloud, we have to figure out what type of layer it is and where to insert it in the stack. We could just add thin layers at several levels with fractional area similar to the layers nearby – effectively, we go back to exanding the existing layers but within each layer, allow some horizontal shift of the new cloud relative to the existing, so that each layer’s area coverage increases.

    This layering discussion is just meant to be illustrative of what could happen if certain things are held constant while other things change.

    Comment by Patrick 027 — 10 Dec 2010 @ 5:18 PM

  75. “Denialist” is tried and true.

    “Contrarian” smacks of stubborn but mostly harmless eccentricity that sometimes pays off– investing in bonds during a bull market, for instance. “Climate fabulist” may be closer, is humorous and may even hint at the pathological, but perhaps it doesn’t get at the undercurrent of pernicious meanness that one encounters all too often?

    Hard to judge the pain/pleasure trade-off that people calculate when ego decouples from grinding rigor to pursue empty glory. The cost should include the scientific community but should also extend to the estimation of larger portions of the public (in effect the media); to get rotten ideas marginalized, kicked to the curb, washed out of popular consciousness, and redirected to sewerage treatment: There’s the ticket.

    Comment by Radge Havers — 10 Dec 2010 @ 5:27 PM

  76. MR 53,

    I really like “Oil Soldiers.”

    Comment by Barton Paul Levenson — 10 Dec 2010 @ 5:34 PM

  77. Please see Dr. Joel Norris’ interesting colloquium lecture to Fermilab at this site,

    http://www-ppd.fnal.gov/EPPOffice-w/colloq/Past_09_10.html

    “Cloud feedbacks on climate: a challenging scientific problem,” 12 May, 2010

    I found it to be a very illuminating treatise on the subject, as I’m not an atmospheric scientist! Nobel Laureate Dr. Leon Lederman is in the audience as well as many other famous international physicists.

    (Lindzen also gave a colloquium talk, it is worth watching to see him dodge some very pointed retorts from audience members!)

    Comment by CRS, Dr.P.H. — 10 Dec 2010 @ 5:39 PM

  78. SA 68,

    Of course, my favorite term for them is “Crazy destructive bastards,” but it tends to get edited out of blogs.

    Comment by Barton Paul Levenson — 10 Dec 2010 @ 5:41 PM

  79. Fred: I’m not exactly sure which Spencer technique you’re referring to. However, regressing fluxes vs. surface temperatures is an accepted method of looking at feedbacks. It’s what I did in my paper.

    Jianhua Lu: What you’re really talking about here is the total energy budget. That’s a great idea, but as Kevin Trenberth famously pointed out, we cannot really close the heat budget yet.

    Mike: My analysis says nothing about how clouds change … all I’m looking at is the change in the globally integrated amount of energy trapped by clouds as the climate warms. I can say nothing about the cause: whether it’s due to changes in high vs. low clouds, changes in cloud thickness, particle phase/size, etc.

    Comment by Andrew Dessler — 10 Dec 2010 @ 5:42 PM

  80. I second Lou @ 10, Andrew, much thanks for the link to your paper. Note to Gavin…how’s the quest against de

    Comment by lucien p. locke — 10 Dec 2010 @ 5:48 PM

  81. sorry….lost part of the reply..

    should read Note to Gavin ….how’s the quest against misinformation going?

    Comment by lucien p. locke — 10 Dec 2010 @ 5:49 PM

  82. Andy, Raypierre, and others – If I might, I would like to make one further attempt to clarify in my own mind the source of discordance between Andy Dessler and Roy Spencer. I’ll do it by mounting a “semi-devil’s-advocate” defense of Spencer, hoping for comments.

    Let me preface this by stating that I agree with both authors that one can’t extrapolate short term ENSO responses to long term feedbacks mediated by CO2. I’m also aware of observational data implying long term positive feedbacks in response to long term warming, but my focus here is on the ENSO-related data.

    I’ll start with a simplified hypothetical scenario involving an El Nino. The simplification will ignore LW events and focus on SW feedback, where a “negative flux” refers to an increased heat loss to space (e.g., from an increase in cloud albedo). I also emphasize that my scenario is not a proposed description of what actually happens, but an attempt to illustrate Spencer’s logic.

    Consider an El Nino initiated by a slackening of Easterlies in the tropical Pacific, leading to reduced cold water upwelling. Consider also the following possible sequence, without prejudging cause/effect relationships.
    (a) The ocean surface warms.
    (b) Cloud formation increases, leading to a negative SW flux.
    (c) Ocean temperature is moderated downward. This may mean a cooling, but not necessarily. It might simply mean that a continuing El Nino warming is flattened. Note that (c) might be caused by (b), but at this point, we won’t speculate over every possible reason for very short term SST variations during an El Nino.

    Let’s examine the above relationships. The a/b relationship correlates ocean warming with increased heat loss to space. This implies a negative feedback. On the other hand, the b/c relationship relates an increased heat loss to space with an ocean cooling (or diminished warming). This implies a positive feedback.

    Which relationship is the critical one? I expect this depends on timing. If it can be shown that the negative SW flux follows the ocean cooling or diminished warming – i.e., (c) precedes (b) – a positive feedback can be deduced. On the other hand, if it can be shown that (b) follows (a), negative feed back is implied. My problem with the data is that the timing of a, b, and c is difficult to ascertain. Roy Spencer chooses a three month interval to evaluate the temperature/flux (a/b) relationship, but the choice is not particularly well justified simply through his use of correlation coefficients. As far as I can tell, Andy Dessler’s data are consistent with a positive feedback (c precedes b) relationship, but that conclusion requires us to know the temporal relationship, perhaps on very short, intra-monthly timescales, and does not exclude the possibility that the temperature changes are a consequence rather than a cause of the flux changes.

    Note that this hypothetical scenario does not challenge the mechanism underlying the initiation of El Ninos, but involves fluctuations occurring during the course of the El Nino.

    Comments would be welcome.

    Comment by Fred Moolten — 10 Dec 2010 @ 8:45 PM

  83. Somehow associated with ENSO is the ~3.75 year period Rayleigh wave in the North Pacific in association with the rapidly (weeks) returning equatorial and then coastal Kelvin wave. It appears that the North Pacific is resonate for this period and the only question about it which puzzles me is how ths is energized. Obviously not clouds.

    Comment by David B. Benson — 10 Dec 2010 @ 10:41 PM

  84. Oops.

    Rossby wave, not Rayleigh.

    [Post in haste, renpent at leisure.]

    Comment by David B. Benson — 10 Dec 2010 @ 11:19 PM

  85. Patrick: Thank you for that detailed explanation. It’ll take me a little while to digest it.

    Bart: Sorry, I’m still confused on Spencer is trying to say. It seems inconsistent, but perhaps I’m not taking a sufficiently nuanced look at it. I could understand if he wants to study temperature as a feedback of clouds instead of clouds being the feedback. Go for it, let us know how it works out.

    But I’m still lost what Spencer is trying to say regarding ENSO if it’s not cloud changes causing it. Take the part you quote:

    El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures.

    Is he saying that currents shift, somehow, and changes to the atmospheric-ocean circulation causes a change in cloudiness and that change in cloudiness changes the sea temperature?

    I’m not sure if I’m just being dense or the different things he says are really incongruent.

    Trent: I had not heard of the Cornwall Alliance before today. I wish I hadn’t heard of it today. It is indeed Roy Spencer in the video you link to if the captions are to be believed. Poking about with google led me to this blurb about it. The war against science continues with the shadow figures trying to bring religion to heel. [mods feel free to delete the last]

    Comment by David Miller — 10 Dec 2010 @ 11:30 PM

  86. 52 Mike Roddy: Somebody on dotearth objected to being called a “denier” because he thought that that is too much like being called a holocaust denier. I answered: “The holocaust that GW will cause will be far worse than the Nazi holocaust. It will be Billions rather than mere Millions of deaths. That is why we want strong action to stop GW and that is why the term “denialist” or “denier” is appropriate. Mother Nature is far better than the Nazis were at killing, so don’t anger Mother Nature. 99% of all species that ever lived are extinct. Homo Sap is no exception.”

    Comment by Edward Greisch — 11 Dec 2010 @ 1:41 AM

  87. I pop in from time to time to share info and climate affairs with you all as long term contributers would know.
    Thought I’d enlighten you on the state of SE (Sunshine coast) Queensland Australia. Last summer (dec-mar) we had the outright highest temp for a single day and the longest consequtive period of temps avove 35C on record. This last winter (june-sept)we had the wettest and one of the warmest on record. This spring up to today it’s again been the wettest on record by quite a huge margin. Our records here date back around 90 years.
    The climate here (for the last year) is now one of high humidity and almost daily showers or rain. I can count on two hands(8or9) how many completely fine days we have had since this time last year. We are certainly in grips of an unusually severe climate change enhanced La-nina. I have lived in this region for 30 years now I have never experienced weather like this before. Is just our climate going haywire or are other contributers to RC also suffering from changed climatic patterns in thier respective neck of the woods?

    Comment by Lawrence Coleman — 11 Dec 2010 @ 6:05 AM

  88. Monckton meets Spencer (and Douglass) in Cancun, here is his report:

    http://www.resistnet.com/group/watchdogforcapandtradebill/forum/topics/lord-moncktons-notes-from-1?xg_source=activity

    Comment by andreas — 11 Dec 2010 @ 6:51 AM

  89. Above (at 82), I offered a “semi-devil’s advocate” defense of the Spencer argument, based on fluctuations within the course of an El Nino or La Nina. Here, I do the same in rebuttal, supporting the Dessler claim that Spencer’s argument would require cloud changes to be a major causative factor in those phenomena. If one looks at Dessler’s Figure 1 b and c, it is clear that during the 2007-2008 La Nina, when the ocean surface was cooler, the set of delta-R-cloud values is shifted downward in a heat loss direction. Even if there were some negative feedback within the La Nina once it started, Spencer would have to postulate a separate mechanism to explain why the entire set of values moved downward at the start. It’s not inconceivable (some common factor responsible for cloud changes and the La Nina dynamics), but the mechanism isn’t obvious, and invoking it violates the law of parsimony.

    Comment by Fred Moolten — 11 Dec 2010 @ 8:42 AM

  90. That should be 16 & 20

    Comment by Russell Seitz — 11 Dec 2010 @ 10:47 AM

  91. 20 :
    Speaking of the Antichrist, Roy has his own cross to bear. in 2007 Rush Limbaugh regaled listeners with excerpts from an article in \The Journal of Geoclimactic Studies\ linking global warming not to human action, but the eructions of \Benthic Bacteria\ .

    Impressed by the articles offered math: \ 4δ161x Λ³Жญ5,6,1,8Φ-4 = {(ΣΨ²Њyt3-14๖P9) x 49}/2β x ⅜kxgt-§\ , and references to the \Miocene, Pliocene and Plasticine\ eras, Rush declared the new theory \very convincing \, and announced it had passed muster by his\ own expert climatologist here on staff.\

    The \expert climatologist \ responded with this insufficiently celebrated memo–

    TO: Listeners of Rush Limbaugh on Thursday, November 8, 2007
    FROM: Roy W. Spencer
    RE: GLOBAL WARMING STUDY HOAX

    \Yesterday (11/7/07), a \research study\ was circulating on the internet which claimed to have found the \real\ reason for global warming. Even though the hoax was quite elaborate, and the paper looked genuine, a little digging revealed that the authors, research center, and even the scientific journal the study was published in, did not exist. I sent an e-mail to Rush about the issue regarding the hoax, with a copy of the \research study.\ Unfortunately…he thought that I was calling global warming a hoax, rather than the study\ -

    Comment by Russell Seitz — 11 Dec 2010 @ 10:49 AM

  92. “I agree, Secular Animist. The term “skeptic” gives people like Morano and Watts undeserved gravitas, and provides cover for the likes of Lindzen and Spencer- whose skepticism does not extend to their own work.”

    Might I suggest “Obstructionists?”

    Comment by Birthmark — 11 Dec 2010 @ 12:49 PM

  93. Barton, Radge, Edward, Andreas, et al: My article on deniers just made today’s lead at Alternet. It’ll at least make you all laugh:
    http://www.alternet.org/environment/149120/5_awards_for_the_world%27s_most_heinous_climate_villains/

    Comment by Mike Roddy — 11 Dec 2010 @ 1:51 PM

  94. Why is Spencer regarded as a “credible skeptic”? Anyone who endorse ID is not “credible”. Period. And I say this as a skeptic myself (w.r.t. the severity of AGW).

    Comment by pax — 11 Dec 2010 @ 3:31 PM

  95. Fred Moolten @88 — During El Nino, warm water from the Pacific Warm Pool moves eastward and the storm clouds then form at the new location.

    Comment by David B. Benson — 11 Dec 2010 @ 7:05 PM

  96. Re # 79 (Andrew’s response):

    Andrew, Thanks for your response. The following are just some of my thinking on the basic concept of climate feedback, not related to your debate with Dr. Spencer, so maybe off the topic.

    I agree with Kevin Trenberth that we cannot really close the heat budget yet, but eventually we would be able to do so, for example in the coupled reanalysis CFSR.

    On the other hand, the climate model simulations do close heat (more precisely, energy) budget of the whole climate system, not only at the surface, but useful information about the 3D energy cycle in climate system, other than the radiative and heat fluxes at the TOA and the surface, are not archived, possibly because they were thought not useful to understand the climate sensitivity, if the climate feedback analysis is based on the radiative balance at the TOA.

    While the TOA-based framework does provide convenience for the public to understand climate change, could it also cause some confusion about the physics of climate change?

    As Bony et al. (2006) point out, the concept of climate feedback and diagnosis method are borrowed from Bode (1945), but possibly there are some key difference between the climate feedback and feedback system in Bode (1945). A feedback is ” induced input from the output”. We usually think the output is surface temperature, and the input the radiative perturbations due to the changes in water vapor, clouds, lapse rate, and ice/snow.

    However, we may take a different view on the climate forcing and feedback ( http://www.springerlink.com/content/01x217g814n32v8u/): climate forcing is external forcing that perturbs the 3D energy-cycle of the climate system, and the climate feedbacks are the adjustments in 3D energy-cycle of the climate system. Both are not necessarily at the TOA.

    Then, the surface temperature change (output) is only just a part of climate responses (OUTPUTS), the radiative feedbacks at the TOA are just the the vertical integration of energy transfer/transport.

    If birds could write a climate model, they might choose air temperature at their flying height as “output”;

    If God does not like human’s selfishness and kicks the Earth and slows down its rotation a little bit, the surface temperature will also change in the new equilibrium even though the forcing ( the kicking by God) shows no radiative forcing at the TOA.

    Comment by Jianhua Lu — 11 Dec 2010 @ 7:13 PM

  97. Mike Roddy 92

    Thanks, I enjoyed that!

    Comment by Radge Havers — 11 Dec 2010 @ 9:30 PM

  98. Fred: In your example, there is increased flux to space with warming (even if the warming is diminished relative to a no-feedback case). My method would pick this up as a negative feedback.

    Jianhua Lu: You make many interesting points. The standard way of determining feedbacks is by considering TOA fluxes and surface temperatures (this goes back at least 2 decades to Cess and colleagues). Ray P. had a post a while back talking about why TOA fluxes matter (unfortunately, I couldn’t find it … maybe Mike et al. could put a link in line). Referencing flux changes to surface T is, indeed, an arbitrary choice, and other legitimate choices exist. The important thing is that, whatever choice you make, you must analyze the models in exactly the same way. Then the comparison is apples to apples. That’s what I’ve done in my paper, so I’m comfortable that the work does indeed suggest models are doing a good job.

    [Response: There are various places where I've talked about the primacy of TOA fluxes. Andy, you may be thinking of my post on Gilbert Plass. The first place I talked about the general issue was in my JAS paper, "Thermostats, Radiator Fins, and the Local Runaway Greenhouse." People who really want to understand how the TOA budget determines surface temperature, though, should read Chapter 3 of my book, Principles of Planetary Climate. There is also an extensive discussion of the surface budget fallacy in Chapter 6. A more elementary version of the same stuff appears in my book with David, The Warming Papers. It is quite natural to correlate the TOA terms with surface temperature, because it is surface temperature we wish to predict. Oh yes, and there is also a concise discussion of the slope of TOA budget vs. temperature and how that relates to climate sensitivity in Chapter 3 of the NRC Climate Stabilization Targets report. Off to AGU soon! --raypierre]

    Comment by Andrew Dessler — 11 Dec 2010 @ 11:51 PM

  99. Andrew, Lu: the earlier posts by Ray Pierrehumbert relating to the TOA vs. surface budgets are here and here.

    By the way, for those interested in that stuff, Judith Curry has a recent blog posting on why she thinks the no-feedback climate sensitivity (~1.2 C per doubling) may not be being computed correctly, but part of her misunderstanding comes down to the crucial distinction between radiative forcing defined at the surface vs. TOA/tropopause. I left a comment there already.

    Back to this topic though, I don’t know how much stock I put in climate sensitivity estimates or feedback behavior derived from these types of analyses, although the Dessler paper is certainly another study to put into the large bag of efforts to advance the science…just as the Clement paper found evidence for a local, positive feedback from low clouds. These analyses say only a little on their own, but part of what makes this subject so interesting for me is taking all of these different approaches, interrogating subsets of the issue from different angles, and coming up with a coherent template for the future.

    I’m not sure if there’s any good way to complete the picture on the long-term cloud feedback in response to more CO2 aside from waiting until we actually see it happen. The cloud feedback is much harder to model or to just work your intuition through than it is for the other feedbacks, which have become much easier to analyze. For this reason, it’s important to have different observational studies (examining radiation-temperature relations, specific cloud type responses and mechanisms, theoretical arguments, and improved modeling), all of which can act to work in tango to converge on the most plausible outcome for the response to anthropogenic perturbations. In that respect, Spencer’s claim that this is a step backward for science, just because it doesn’t fit into his “cause and effect” paradigm he has been preaching, is simply indefensible.

    In general, I think Holocene provides pretty good constraints on the magnitude that we could expect any ‘unforced trends’ to operate on climate timescales. No one has proposed any mechanism that would allow clouds or water vapor to suddenly shift into a completely new regime on their own and stay that way, acting to artificially introduce a “feedback looking forcing” that is internally imposed on the system. The key question in that regard is whether there is some dependence on initial conditions or “mode of variability” that can swamp the forcing expected from a doubling of CO2, and there’s no observational or model evidence that this happens in Holocene-like conditions. So the paleoclimatic evidence for climate sensitivity doesn’t really suffer from Spencer’s alleged issue as the “5 year dataset” type papers that examine correlations might, although I agree with Andrew Dessler that his doesn’t either.

    Comment by Chris Colose — 12 Dec 2010 @ 3:11 AM

  100. http://www.springerlink.com/content/01x217g814n32v8u/
    is the correct link (lose the trailing parenthesis included in the original) for:
    Climate Dynamics
    Volume 32, Number 6, 873-885, DOI: 10.1007/s00382-008-0425-3
    A new framework for isolating individual feedback processes in coupled general circulation climate models. Part I: formulation
    Jianhua Lu and Ming Cai

    Comment by Hank Roberts — 12 Dec 2010 @ 3:43 AM

  101. Mike 92,

    Excellent article. Thanks.

    Comment by Barton Paul Levenson — 12 Dec 2010 @ 5:55 AM

  102. Something appears to be wrong with the el-nino ,la-nina cycle. I live on the Sunshine coast in Queensland Australia and I have always known that in a La-nina period our eastern seaboard is warmer with respect to America’s west coast resulting in increased rainfall here in Queensland but pretty dry conditions from California down to patagonia etc. We have had the wettest year to date on record, the coolest spring and now summer. The wettest august to december on record..etc..you kinda get the impression that’s it’s pretty soggy down here. However casting my eyes and ears over to the west of the americas and they have also had extreme rainfall, massive flooding in central america. Why are both sides of the pacific undergoing such unprecedented precipitation? You all know that australia is the driest continent but we have had over the entire last year less than 10 days of ‘fine’ weather. It’s either overcast or showery or days on end of solid rain which is hammering on the roof as I type.
    I have been in this region for over 30 years now and never have we had to endure such difficult weather. Is this the result of climate change amplifying the la-nina? Last year we(and many other cities in australia) had the hottest day on record as well as the longest spell of days over 35C on record. It’s getting quite wild and wooly here!

    Comment by Lawrence Coleman — 12 Dec 2010 @ 6:14 AM

  103. I’m confused.

    I just read Spencer’s 12/9/2010 blog post which states:

    In their interpretation, if one observes a warmer year being accompanied by fewer clouds, then that is evidence of positive cloud feedback. Why? Because if warming causes fewer clouds, it lets in more sunlight, which then amplifies the warming. That is positive cloud feedback in a nutshell.

    Huh?

    Doesn’t a positive cloud feedback mean that MORE clouds will contribute to more warming? My non-scientific understanding was Increased warmth=increased evaporation=increased clouds=increased warmth and so forth. Living in Minnesota, I witness a positive cloud feedback – and the opposite – many times all winter long. Yesterday was cloudy and warm. Today it is sunny and bitter cold. Tonight will be clear night and it’s going down to -16 F.

    I thought it was the Lindzen/Spencer camp that argued for a negative cloud feedback, the complement of which would be a sunny sky positive feedback.

    Am I confused or has Spencer become unhinged?

    Comment by JiminMpls — 12 Dec 2010 @ 8:29 AM

  104. I read an interesting article at NASA about a new study on negative feedback.
    The lead author was Lahouari Bounoua, of Goddard Space Flight Center.

    The article says warming will continue but that the rate of warming may be slower. That would be nice, if true. What do you think of this research?

    http://www.nasa.gov/topics/earth/features/cooling-plant-growth.html

    NASA writes:

    To date, only some models that predict how the planet would respond to a doubling of carbon dioxide have allowed for vegetation to grow as a response to higher carbon dioxide levels and associated increases in temperatures and precipitation.

    Of those that have attempted to model this feedback, this new effort differs in that it incorporates a specific response in plants to higher atmospheric carbon dioxide levels. When there is more carbon dioxide available, plants are able to use less water yet maintain previous levels of photosynthesis. The process is called “down-regulation.” This more efficient use of water and nutrients has been observed in experimental studies and can ultimately lead to increased leaf growth. The ability to increase leaf growth due to changes in photosynthetic activity was also included in the model. The authors postulate that the greater leaf growth would increase evapotranspiration on a global scale and create an additional cooling effect.

    “This is what is completely new,” said Bounoua, referring to the incorporation of down-regulation and changed leaf growth into the model. “What we did is improve plants’ physiological response in the model by including down-regulation. The end result is a stronger feedback than previously thought.”

    Comment by Snapple — 12 Dec 2010 @ 9:30 AM

  105. @73: My question in 73 was based on a Science News article on Dessler’s paper. That article erroneously equates “positive feedback of clouds” with “more clouds cause more warming”.

    Comment by Mike — 12 Dec 2010 @ 10:33 AM

  106. Hint. The reduction in planetary cloud cover post 1994 is due to solar wind bursts that remove cloud forming ions via the mechanism Tinsley calls electroscavening. (See Tinsley’s paper for details.) The solar wind bursts have abated. GCR is high. What will happen next?

    http://www.skepticalscience.com/images/cosmic_clouds.gif

    Although there was a correlation between GCRs and low-level cloud cover until about 1991, after that point the correlation broke down (Laut 2003) and cloud cover began to lag GCR trends by over 6 months, while cloud formation should occur within several days (Yu 2000).

    http://www.utdallas.edu/physics/faculty/tinsley/Role%20of%20Global%20Circuit.pdf

    Comment by William — 12 Dec 2010 @ 11:49 AM

  107. Sorry to butt in, but today the life and achievements of Dr. Stephen Schneider are being celebrated at Stanford. After the memorial, these talks will be presented:

    “Climate-Change Science and Sanity: Steve Schneider’s Extraordinary Contributions to Both”—John Holdren

    “Why We Resist the Results of Climate Science”—Naomi Oreskes

    “The American Public’s Understandings and Misunderstandings About Climate Change: Is There a Crisis of Confidence in Climate Science?”—Jon Krosnik

    It’s lucky God sends us wise men and women who fight for our people and the whole world.

    It’s sad that a some people don’t know of or don’t appreciate his contributions, but I think he will be in the history of science books as a great scientist.

    http://legendofpineridge.blogspot.com/2010/12/life-and-achievements-of-climate-expert.html

    Comment by Snapple — 12 Dec 2010 @ 11:50 AM

  108. Regarding the recurring debate about what to call AGW deniers, how about “Canutes”? King Canute demonstrated the futility of standing against nature to his courtiers by showing them that he could not command the tide, but that has been forgotten in the stories about the King who thought he could control the sea. The story as told today has everything: arrogance, misinformation, and just enough truth in it to sound plausible. Sound like anyone you know?

    Comment by One Anonymous Bloke — 12 Dec 2010 @ 12:08 PM

  109. There is a Wikipedia article on cloud feedback that could use some updating. Even what is there does not seem to be correct in places.

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

    Comment by Mike — 12 Dec 2010 @ 12:13 PM

  110. Oh, and it has a wise man whose words and lessons have been twisted to mean the opposite of what he originally said.

    Comment by One Anonymous Bloke — 12 Dec 2010 @ 12:13 PM

  111. Snapple @102 refers to a NASA report as saying

    When there is more carbon dioxide available, plants are able to use less water yet maintain previous levels of photosynthesis. The process is called “down-regulation.” This more efficient use of water and nutrients has been observed in experimental studies and can ultimately lead to increased leaf growth. The ability to increase leaf growth due to changes in photosynthetic activity was also included in the model. The authors postulate that the greater leaf growth would increase evapotranspiration on a global scale and create an additional cooling effect.

    In the first sentence they claim that, with increased CO2, plants can use less water. In the final quoted sentence they suggest that plants will use more water. These seem to be contradictory. In any event, cooling as a result of increased evapo-transpiration is a purely local effect, as the heat of vaporization is released again when the water condenses.

    I should add that I am not convinced that increased plant growth is a necessary consequence of increased atmospheric CO2, given the complex interactions involving herbivores, diseases, nutrient availability and so on.

    Comment by Richard Simons — 12 Dec 2010 @ 12:23 PM

  112. Re # 97

    Andrew: First I agree with you that the models are doing a good job,though we never expect they are perfect. My points are not contrary to the TOA flux-surface temperature connection. In fact, in the link I previded [BTW, would Gavin or anyone else make a change in #95 by adding a space between "/" and "):" ?], the TOA-flux equation, abtained by the vertical integration of total energy conservation equation of (atmosphere+land surface + ocean), is eaxactly the same as the one long been used by Cess et al.

    There are indeed differences in my view with the TOA-based view. First, the doubling CO2 forcing at TOA (~4 W/m2) may be an oversimplied view on the real influence of doubling CO2. Its vertical structure as shown in http://www.springerlink.com/content/q8265w78n98480w8/ (which basically is a revisit of classic Manabe-Wetherald 1967 model) may have profound infuence on the dynamics and energy cycle of the climate system. The fact that radiative forcing of doubling CO2 at the TOA is largest in the tropics is well-known in the community, but that the forcing at the surface is largest at the high-latitudes may be surpring to the community ( http://www.springerlink.com/content/6677gr5lx8421105/ ). Second, I am more interested in the chain-reaction (the connection between the physical processes, linked by the dynamics and the energy cycle) of the climate system to the external forcing, rather than which is the largest contributor to the uncertainty. In this sense, the TOA-based analysis may have its weakness because the feedbacks are more or less separately treated.

    raypierre: Your 1995 JAS paper is one of the few papers inspiring me very much, also thanks for the information about the new NRC report. I agree with your critics on Ramanathan’s thermostat hypothesis and about the surface budget fallacy. The TOA-flux-only method is one way to remedy the surface budget fallacy, but the fallacy may also be remedied by consideraing the surface budget together with atmospheric budget, or by considering all terms in the surface budget. In my impression, the benifit of the inclusion of surface flux budget is for us to get a better understanding about the relation between hydrological cycle and global warming, on which my view may also be different from – but not totally contrary to – the published literatures.

    Comment by Jianhua Lu — 12 Dec 2010 @ 12:33 PM

  113. Andy (97) – You state: “Fred, In your example, there is increased flux to space with warming (even if the warming is diminished relative to a no-feedback case). My method would pick this up as a negative feedback.”

    It would be deemed “negative” only if the Planck response is subsumed under the term “feedback”. In the more conventional sense, I would see it as positive. A “positive” feedback even if the Planck response is included (e.g., a reduced energy flux to space in response to a 2% increase in solar irradiance) would be a dire situation for Earth to space if it persisted, would it not?

    Comment by Fred Moolten — 12 Dec 2010 @ 1:10 PM

  114. Snapple @ 102, (the Happy Plant paper) it is a good general rule to not put too much stock in a pres release, and sometimes it seems that the worse the press release, the more attention it gets. Ignore this PR. Here’s the abstract.

    From comments at Romm’s they use a very low sensitivity model, double CO2 from 350 to 77 ppm, and expect plants to thrive globally (!) so much that the increased growth, hence transpiration, speeds up the water cycle and reduces sensitivity still more. Good luck with that.

    Comment by Pete Dunkelberg — 12 Dec 2010 @ 1:51 PM

  115. Oops 77 should be 700.

    Comment by Pete Dunkelberg — 12 Dec 2010 @ 1:53 PM

  116. It’s hard to believe a practising scientist can be so obtuse. At no point does Spencer say, or even infer that ENSO is anything other than the stochasctic event you describe. And yes I have read the link [edit for inappropriate language] …his argument is that an event which exaggerates temperature is the best time to investigate the effects of that temperature on the climate system. How [do] you go from that to saying that Spencer says clouds are causing ENSO? [edit]

    Comment by JamesG — 12 Dec 2010 @ 1:59 PM

  117. James G (114) – Spencer doesn’t explicitly state that cloud changes cause El Ninos or La Ninas, and may not even think it, but his logic implies it. To repeat an example I cited earlier, look at Dessler’s Fig. 1b and 1c. We observe a 2007-2008 La Nina with its characteristic ocean surface cooling, associated with a shift in cloud properties during that entire event in the direction of increased heat loss (i.e., cooling). Now if the La Nina cool ocean surface conditions caused the clouds to moving in a heat loss direction, that is a clear positive (magnifying) feedback. Spencer’s rebuttal is that cloud changes occur first, and the ocean changes are a consequence, and so the cloud changes can’t be described as a feedback on the ocean changes. Applied to the 2007-2997 La Nina as well as other episodes in the record, that argument is saying in essence that changes in clouds caused the La Nina cooling. We know enough about the mechanisms underlying ENSO events to reject that explanation, and Spencer himself is not claiming that type of causality. His logic, however, appears to be making that claim.

    Comment by Fred Moolten — 12 Dec 2010 @ 2:33 PM

  118. A side query: Given my questions about the CO2 forcing formula [F=A*ln(CO2/CO2_i)], is it correct to say that any of these cloud feedback and/or forcing scenarios do not change the basic CO2 forcing formula? In other words the CO2 forcing (though not sensitivity) stands on its own and it per se is not directly altered by other forcings or feedbacks?

    Comment by Rod B — 12 Dec 2010 @ 2:38 PM

  119. Whenever the issue of additional plant growth with additional CO2 comes up, I think back to the day when W canceled FACE (Free Air CO2 Enrichment) with the experiment just ten million short of completion.

    Mission unaccomplished?

    Comment by JCH — 12 Dec 2010 @ 2:42 PM

  120. Listen to Eli Andy. You have nothing to gain what so ever trying to engage the likes of Spencer or Lindzen in meaningful dialogue. Roy is nothing less than a narcissist.

    In Roy’s own words:”First, we skeptics already know your arguments …it would do you well to study up a little on ours.

    And second, those of us who have been at this a long time actually knew Galileo. Galileo was a good friend of ours. And you are no Galileo.”.

    Neither are you Roy. But you did look good on TV.

    Anyone needs a link to that page I’ll be happy to supply it.

    Comment by Ron Crouch — 12 Dec 2010 @ 7:01 PM

  121. So what causes the changes to clouds during an ENSO event? It is primarily due to changes in global temperature? Or do changes of ocean and atmospheric circulation play a large role?

    Comment by Michael — 12 Dec 2010 @ 7:15 PM

  122. Dr Dessler,

    Do the findings hold up if you change the time period you do the analysis for? I know you only have ten years of data but if you start or finish a year or two earlier does this affect the 0.54±0.74W/m2?

    Comment by HR — 12 Dec 2010 @ 7:40 PM

  123. Rod@116, I believe that is basically correct, and I commend you for making A a coefficient rather than an exponent.

    And Fred, the increased radiation as temperature rises is definitely a negative feedback–in fact the predominant one in most cases.

    Comment by Ray Ladbury — 12 Dec 2010 @ 7:49 PM

  124. 101Lawrence Coleman says:
    12 December 2010 at 6:14 AM
    Something appears to be wrong with the el-nino ,la-nina cycle. I live on the Sunshine coast in Queensland Australia and I have always known that in a La-nina period our eastern seaboard is warmer with respect to America’s west coast resulting in increased rainfall here in Queensland but pretty dry conditions from California down to patagonia etc. We have had the wettest year to date on record, the coolest spring and now summer. The wettest august to december on record..etc..you kinda get the impression that’s it’s pretty soggy down here. However casting my eyes and ears over to the west of the americas and they have also had extreme rainfall, massive flooding in central america. Why are both sides of the pacific undergoing such unprecedented precipitation? You all know that australia is the driest continent but we have had over the entire last year less than 10 days of ‘fine’ weather. It’s either overcast or showery or days on end of solid rain which is hammering on the roof as I type.
    I have been in this region for over 30 years now and never have we had to endure such difficult weather. Is this the result of climate change amplifying the la-nina? Last year we(and many other cities in australia) had the hottest day on record as well as the longest spell of days over 35C on record. It’s getting quite wild and wooly here.
    ______

    We are straying a bit from topic here but I would suggest the potential that the acceleration of the hydrological cycle could be showing itself in changes in the normal La Nina patterns. This acceleration, long seen in the carbon-rock cycle could already be leading to greater downpours (and snow falls in colder climates) worldwide. We only need to reflect back on Pakistan this past summer. This acceleration of the hydrological cycle, which is a natural negative feedback response to increased CO2 is normally a long-term geological process, taking hundreds of thousands and even millions of years through the weathering of rocks that would absorb CO2 from the atmosphere and return it to the oceans. With the 40% increase in CO2 since the 1700′s, we would expect to see the hydrological cycle accelerate, and where better than in changes to one of most potent drivers of weather on earth– the ENSO cycle.

    Comment by R. Gates — 12 Dec 2010 @ 8:20 PM

  125. I find this ENSO discussion very apt to the times. Clouds are but a small part of ENSO shaping.
    World wide, they are largely boosted in extent during El-Nino and very much reduced during La-Ninas. I read with interest the lack of further details , clouds do not form without seeds, El-Ninos need very weak Easterly equatorial winds, or of course Westerlies as well. But a great player, which I deal with a lot, is Upper Air lapse rates, which are not
    confined to the equator, but may morph a whole lot in unison world wide, as a result of extra heat injected in it (by any source). Such as is done during El-Ninos. NOAA ENSO discussion page http://www.cpc.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.pdf
    correctly deals with the term convection, all about lapse rates, in its varying degrees, from unstable to very stable.
    Its hard to imagine clouds without convection, or appropriate lapse rates.
    The biggest trigger for ENSO switching may be the injection of heat affecting convection, so it was from January 2010 the warmest Upper Air in that months history, a trigger, affecting the very nature of Upper Air everywhere, and in particular over The equatorial Pacific. I rather think that the ideal cloud maker is a very warm surface compared to the immediate Upper Air. Adding heat may be stabilizing the atmosphere, which given a cooler surface (naturally by winter) favors inversions rather than convection. The extra heat given by clouds as suggested by Andrew, is very interesting, And may add to the process of ENSO switching.

    Comment by wayne davidson — 12 Dec 2010 @ 10:42 PM

  126. Does not the cooling associated with the ‘pollution’ associated with China imply a negative feedback? ie. Pollution providing an added stimulation for cloud formation on top of the increased rate from temperature increase.

    Comment by Andrew Sheldon — 12 Dec 2010 @ 11:13 PM

  127. Re 116 Rod B – yes. Clouds and water vapor and temperature distribution affect CO2 forcing, but these things are the way they are for the present (or recent) climate; how they will change doesn’t affect the CO2 forcing when the present (or recent) climate is the starting point (the climate state is described by weather over a sufficient period of time such that other such periods of time are sufficiently similar – the forcing won’t be the same for a particular time and place of course, or even necessarily just a particular time (though perhaps the global average doesn’t vary too much (?)- so far as I know; maybe some small seasonal cycle?). The way feedbacks can affect forcings is:

    Suppose we double CO2 and it’s a forcing of 4 W/m2 (rounding for simplicity of discussion). Then we have feedbacks, which result in a 3 K warming equilibrium (setting aside range of uncertainty, ice sheets, etc.). Once we reach equilibrium, assuming no hysteresis, if CO2 is halved, then the new equilibrium temperature will be 3 K cooler – the original temperature. But the forcing could be smaller (or larger, at least for the most general case where we haven’t determined how anything works) in magnitude – perhaps (for sake of argument) -3.8 W/m2 instead of -4 W/m2. This could be because the lapse rate is now smaller than before (although the increased height of the tropopause would have the opposite effect), there may be more overlap between H2O and CO2 (depending on how it works at at the tropopause level), etc. But the feedbacks will now make the climate more sensitive – for example, having removed some CO2, there is less overlap with CO2 to reduce the water vapor feedback. Etc. Without hysteresis, the equilibrium climate will return to the same value if the external forcing agents return to the same condition, but they’re radiative forcings could be different; the climate sensivity will vary in a compensating way. This could be neglected for smaller changes – it is important for large changes such as removing all CO2 vs adding CO2 from an initially zero-CO2 condition (setting aside snowball hysteresis) – hence, CO2′s contribution to the ~ 155 W/m2 total greenhouse effect for the present/recent climate is not the same as the CO2 forcing starting with none and adding it all back – even the total 155 W/m2 value would be different if we started with no greenhouse effect and added the clouds and water vapor and CO2, etc, because of the change in the temperature profile.

    Comment by Patrick 027 — 12 Dec 2010 @ 11:24 PM

  128. because of the change in the temperature profile. – the change in surface temperature, the change in the lapse rate(s), the change in tropopause height, the change in horizontal and seasonal and other variations if we are going beyond a 1-dimensional model, etc.

    Comment by Patrick 027 — 12 Dec 2010 @ 11:28 PM

  129. … without hysteresis, a single-valued function of climate sensitivity and of radiative forcings per unit change in external forcing agents could be found by considering the graph of equilibrium climate over external forcing agent variations – the slope of that graph at each point is a climate sensitivity per unit forcing agent, and at any point, with a particular equilibrium climate, their is a radiative forcing change per unit forcing agent, etc. (At least for those external forcing agents which work via radiative flux.)

    Comment by Patrick 027 — 12 Dec 2010 @ 11:35 PM

  130. Patrick and Ray, thanks for the info

    Comment by Rod B — 13 Dec 2010 @ 12:41 AM

  131. Fred #115, Wayne #123 and Andrew. The idea that clouds etc do not trigger ENSO that has been suggested above may not actually be the case. A recent study shows that it could well be the dominant factor at work.

    http://www.agu.org/pubs/crossref/2010/2010GL044888.shtml

    Or the pre-print at

    http://users.monash.edu.au/~dietmard/papers/dommenget.slab.elnino.grl.pdf

    Comment by Terry — 13 Dec 2010 @ 12:44 AM

  132. Re: Labels for denialists.

    I’m partial to use of the self-coined adjective “sui-genocidal” as sui-genocidist is clumsy on the tongue.

    Comment by ccpo — 13 Dec 2010 @ 1:03 AM

  133. Terry,

    Here’s the end of the abstract from your linked paper, with a few words bolded:
    “The results challenge and extend our current understanding of the feedback mechanisms of El Niño in climate models and may also highlight possible atmospheric mechanisms that could partly control some observed ENSO events.”

    IOW, it’s all pretty tentative, and there is no claim at all that ENSO is actually driven by clouds. Pretty underwhelming, I’d say.

    Comment by Nick Gotts — 13 Dec 2010 @ 9:43 AM

  134. #129, Thanks for the links! Clouds are part of the entire process, as always, but no clouds exist without seeds and appropriate lapse rates. As far as starting El-Nino, I do not see
    them as a major player, rather clearer skies by La-Ninas cause in essence
    the beginning of El-Ninos. So the lack thereof of clouds is more one of the switching triggers. In the reverse mode, too much clouds, causing too much heat, specifically during winter collapses El-Ninos.

    Comment by wayne davidson — 13 Dec 2010 @ 11:26 AM

  135. 125, 126, 127 (Patrick),

    Interesting. I need some clarification, to be sure that I’m correctly interpreting what you posted.

    … at any point, with a particular equilibrium climate, their is a radiative forcing change per unit forcing agent, etc. (At least for those external forcing agents which work via radiative flux.)

    First, could you clearly define “radiative forcing change?” I’m pretty sure that I know what you mean

    Second, you appear to be saying that the system does have some degree of hysteresis, i.e. that the end state of a change depends on the previous state. All other things being completely equal adding CO2 to a null world in climate state A gives climate state B, then taking it away puts the world in climate state C (not A), and adding it back again might result in climate state B or D (i.e. like B, but not B)… because the changes in CO2 cause semi-permanent changes to the atmosphere, i.e. a “memory” that CO2 had once been there (i.e. a change in lapse rate, height of troposphere, etc.).

    It this a correct interpretation of your statement?

    Third, do you have a source where I could read up on this? It’s entirely new to me.

    Comment by Bob (Sphaerica) — 13 Dec 2010 @ 11:39 AM

  136. Terry (129) – That paper is quite interesting. It uses a slab ocean model to deliberately eliminate ocean dynamics, and finds that a minority of simulations reproduce ENSO-type events from atmospheric changes alone – the majority do not. It concludes that ocean dynamics probably play the dominant role in ENSO, as generally concluded, but that the atmospheric changes, including cloud cover change, can amplify ENSO anomalies and affect timing. The amplification by cloud cover, interestingly, tends to reinforce Andy Dessler’s conclusions about a positive feedback.

    Comment by Fred Moolten — 13 Dec 2010 @ 12:03 PM

  137. 118, Ron Crouch: You have nothing to gain what so ever trying to engage the likes of Spencer or Lindzen in meaningful dialogue.

    I recommend something different. Do engage the likes of Spencer, Lindzen, et al in a meaningful dialogue. You will not persuade Lindzen or Spencer or et al., but there are many people reading and listening in on the debates. Although you address your remarks to L & S et al, you are really aiming to gain influence among the undecideds and other non-participants. People can read the debates, here and at WUWT, and learn over time who is most honest, trustworthy, logically consistent, respectful, at so on. I don’t know who was the first person to say this, certainly not I, but you maintain the debate so that everyone always understands that there are clear alternatives. If your opponents are wrong yet prevail for a while, remember that they can not fool all the people all the time.

    If you have a record of always being honest, direct, polite (even if it’s forced), then when you are proved right people will rally to your side.

    Comment by Septic Matthew — 13 Dec 2010 @ 1:02 PM

  138. Re 132 Bob (Sphaerica)
    First, could you clearly define “radiative forcing change?” I’m pretty sure that I know what you mean

    Example: doubling CO2 has a radiative forcing of (rounded) ~ 4 W/m2; this is the change in radiative forcing that occurs – a radiative forcing change.

    Second, you appear to be saying that the system does have some degree of hysteresis, i.e. that the end state of a change depends on the previous state. All other things being completely equal adding CO2 to a null world in climate state A gives climate state B, then taking it away puts the world in climate state C (not A), and adding it back again might result in climate state B or D (i.e. like B, but not B)… because the changes in CO2 cause semi-permanent changes to the atmosphere, i.e. a “memory” that CO2 had once been there (i.e. a change in lapse rate, height of troposphere, etc.).

    It this a correct interpretation of your statement?

    Allowing time for equilibration (heating/cooling of the oceans etc.), and setting aside the actual potential for hysteresis of that equilibrium climate, no. I mean that if removing all CO2 will shift the equilibrium climate from B to A, adding it back will shift the equilibrium climate back to B. The difference is that the radiative forcing of removing all CO2 in a B climate could easily be different from the radiative forcing of adding it back in an A climate. The feedbacks will be different in a compensating manner (The climate sensitivity to the change in CO2 is preserved; the climate sensitivity to an externally imposed radiative flux is different).

    Comment by Patrick 027 — 13 Dec 2010 @ 5:41 PM

  139. Sceptic Matthew, the question is where and how to engage the Lindzens and Spencers of the world. Eli fully agrees with you that they should be engaged with in the public sphere, but his point is that they play a double game, and they should be treated as the same people in both the scientific and the public discourse. The pattern to date has been to allow them to run naked in public (OK that is really scary), while dealing with them as colleagues professionally. That should stop. They need to be called on their public behavior in private. Something is in the air.

    Sorry for interrupting some interesting stuff with meta.

    Comment by Eli Rabett — 13 Dec 2010 @ 7:06 PM

  140. 135 (Patrick),

    Okay, I misunderstood what you were saying. I missed the nuance that you were saying that the size of the forcing might change but the equilibrium temperature would be the same — which implies that the forcing + feedbacks must be equal-but-opposite, even if the resulting opposing forcings (double CO2, halve CO2) by themselves are not equal-but-opposite.

    Correct?

    Comment by Bob (Sphaerica) — 13 Dec 2010 @ 7:08 PM

  141. Andrew Dessler,

    If the cloud feedbacks are indeed positive and inline with the IPCC model predictions of about a 3 C rise in temperature from a doubling of CO2 (a 3.7 W/m^2 increase gross in radiative forcing; 1.85 W/m^2 net), then why doesn’t the same proportional amount of positive feedback amplification lead to 16+ C rise in temperature when the net albedo adjusted incident solar power at perihelion is about 14 W/m^2 higher? Instead, average global temperatures are actually colder at perihelion in January then at aphelion in July. How do you explain this?

    What is so special about 1 W/m^2 of additional power from CO2 that it’s at least 5 times more powerful than 1 W/m^2 of additional power from the Sun?

    [Response: No idea what you are referring to. A global annual mean radiative forcing from the sun (= delta(TSI)/4*0.7 ) has almost exactly the same effect as the same amount of CO2 related forcing. Changes related to the orbit which impacts seasonal insolation are a whole other kettle of fish (cf. the ice ages), but don't really fall into a neat radiative forcing argument. - gavin]

    Comment by RW — 13 Dec 2010 @ 7:28 PM

  142. Rod B @116 — The Arrhenius formula is only a (good) approximation in the first place, but taking it as constant works well enough for amateur worK:
    http://www.realclimate.org/index.php/archives/2010/10/unforced-variations-3-2/comment-page-5/#comment-189329

    Andrew Sheldon @124 — That is my (amateur) understanding. It ends up be part of the transient climate response in the link just above.

    Comment by David B. Benson — 13 Dec 2010 @ 7:54 PM

  143. “then when you are proved right people will rally to your side.”

    That sounds like something Clevinger would say in Catch 22. What actually happens, if you prove someone’s dearly held belief to be wrong, is that they rip your throat out.

    Besides I think the deniers are just making up arguments to delay having to do anything about it. Even the most anxious of predictions puts the time to pay the piper at 10-20 years down the road. If it’s 50+, all but the youngest of deniers will be dead, secure in the knowledge that they never had to bow to Reality.

    Comment by Jeffrey Davis — 13 Dec 2010 @ 8:27 PM

  144. RW@138

    Methinks you need to revisit your reading about the models of Earth’s climate.

    Comment by Ray Ladbury — 13 Dec 2010 @ 9:42 PM

  145. Jeffrey Davis @140 — You are certain then that various heat & flooding events are not already what you csall paying the piper? For instance, last summer in Russia and Pakistan.

    Comment by David B. Benson — 13 Dec 2010 @ 9:48 PM

  146. 136, Eli Rabett: Eli fully agrees with you that they should be engaged with in the public sphere,

    I was disagreeing with the sentiment expressed by Ron Crouch. If you disagreed with him and made my point ahead of me, I missed it.

    140, Jeffrey Davis: That sounds like something Clevinger would say in Catch 22. What actually happens, if you prove someone’s dearly held belief to be wrong, is that they rip your throat out.

    either you missed my point or else you denied it. The people who will rally to your side will be the people who have not been your opponents. Sort of the way Britons rallied to Churchill after the path of the appeasers was shown to be a disaster. It may be anguishing or threatening to accept that you have lost the public policy debate for the time being (I might be wrong but that’s the way it seems to me now), but staying engaged will win in the long run, and there will be a long run.

    Comment by Septic Matthew — 13 Dec 2010 @ 10:02 PM

  147. Fred # 133, it does seem to be a bit more complex that simply “increased cloud cover = +ve feedback”. I’m not familiar with oceanography nor the intricacies of ENSO modelling (so could be out of my depth), but the authors also found that lack of cloud cover caused a positive SST anomaly ie a -ve feedback w.r.t. shortwave flux depending on the maturity of the event. Since they found both +ve and -ve feedback, it seems to me that feedback studies need to be carefully chosen so that they don’t just focus on one stage of the event. Should be interesting to see if this develops further, and if there is a moving target of +ve and -ve FB.

    Comment by Terry — 13 Dec 2010 @ 10:12 PM

  148. Re 137 Bob (Sphaerica)

    Yes.

    Comment by Patrick 027 — 13 Dec 2010 @ 10:23 PM

  149. #138 RW.
    I think RW’s question is about the 14 W/m2 annual cycle in solar forcing due to the elliptical orbit, and why that doesn’t have a feedback commensurate with that number, i.e. about four times the doubling CO2 warming. To which, I would suggest the answer is thermal inertia. The forcing doesn’t act for long enough to have much of an effect in warming the earth system. Sure, if you sustain 14 W/m2 for a few decades you will get an impressive warming. It has some properties of a forced oscillator with inertia. A higher frequency leads to a smaller and more delayed response cycle.

    Comment by Jim D — 13 Dec 2010 @ 10:27 PM

  150. Re 138 RW

    If you held Earth at perihelion distance for several decades (or shrunk the semimajor axis to equal the present perihelion distance), you would get that warming (assuming your math is correct; actually for the same forcing efficacy, the warming in deg C or K would be a somewhat smaller than the value of forcing in W/m2; anyway, I’m not sure if I’m remembering the Earth’s orbit’s eccentricity correctly). It takes time to reach equilibrium because of the heat capacity of the oceans.

    The forcing of a doubling of CO2 is ~ 3.7 W/m2; the 1.85 W/m2 net forcing you refer to would be the remaining disequilibrium after the climate warms approx. halfway to new equilibrium.

    Comment by Patrick 027 — 13 Dec 2010 @ 10:31 PM

  151. It takes time to reach equilibrium because of the heat capacity of the oceans.

    Well, the heat capacity in general; it happens the oceans dominate the effective heat capacity of the climate system (it takes a very very long time for heating signals to penetrate through the crust, etc.)

    Comment by Patrick 027 — 13 Dec 2010 @ 10:33 PM

  152. RW @ 138: The 3K number estimates the *equilibrium* temperature rise (excepting some slow feedbacks like ice-sheet melting) for a CO2 doubling. But earth probably takes 25-50 years to reach 60% of equilibrium temperature [1], and probably centuries to reach 100%, due to ocean heat storage. Thus, the yearly eccentricity-based forcing does not produce anything like the full equilibrium increment of warming or cooling that its peak value would suggest.

    [1] Hansen et al 2005, http://meteora.ucsd.edu/cap/pdffiles/Hansen-04-29-05.pdf .

    Comment by Meow — 13 Dec 2010 @ 11:41 PM

  153. Sorry this question is late. Dr. Dessler (or someone else who knows the answer) it appears from the discussion above that it doesn’t matter whether clouds cause ENSO or whether ENSO causes clouds, but rather what is the radiative change to changes in clouds no matter what the causes of the cloud changes are. The MERRA assimilation is described here http://gmao.gsfc.nasa.gov/pubs/docs/Rienecker369.pdf which essentially integrates satellite radiance measurements into an AGCM. It describes the radiative equations based on, among other factors, clouds, along with convective equations and specific cloud process equations.

    It seems to me that the scatterplot in your figure 2A depends on the assumptions implicit in those equations along specific parameters (my link page 19) that are determined by fitting the model radiation to the satellite-measured radiation. There are conceivably a range of solutions with such a large number of variables including potential local minimums. While a solution adds credence to the model in general, how do we know that the modeled clouds behave similarly to clouds in the real world with respect to feedback to warming? Is there are other way to measure cloud feedback than such a model?

    Comment by Eric (skeptic) — 14 Dec 2010 @ 5:38 AM

  154. re:140 Pakistan flooding and Russian heat

    Well, I would say those are examples of paying the piper, but I thought the European heatwave of 5-6 years ago was one, as well. Until there’s something more cinematic (literally) I don’t think we’ll get the public’s attention.

    It’s interesting about Pakistan, though. It should have served as an enormous bellwether since a flood that displaced 20,000,000 people and covered 1/5th of a country is huge. But Pakistan is a dangerous Muslim place, and the media in this country definitely downplayed the scope of their tragedy. Whether because of the whole Muslim aspect or because of the flood’s relation to AGW, I don’t know. Both, I suspect.

    re: 143

    At this stage of the game, I don’t think there are a lot of people weighing the arguments between science and the deniers. I think on the whole people “disbelieve” AGW simply because they don’t want to assume the burdens that mitigation will demand. Why, yes, I’ve become pretty misanthropic in my old age. Why do you ask?

    Comment by Jeffrey Davis — 14 Dec 2010 @ 11:37 AM

  155. Are you able to say what drives the ocean-atomsphere system?

    Comment by Richard — 14 Dec 2010 @ 1:14 PM

  156. “…is it correct to say that any of these cloud feedback and/or forcing scenarios do not change the basic CO2 forcing formula?” Rod B — 12 December 2010 @ 2:38 PM

    IMHO, no. One thing that I haven’t seen discussed is that cloud scattering of IR photons makes the effective path length longer; and increases the greenhouse effect at a given GHG concentration.
    see -
    Joint Statistics of Photon Path length and Cloud Optical Depth, Q.-L. Min and L. C. Harrison

    “A mean pressure- and temperature-weighted photon pathlength in the atmosphere can be inferred from moderate resolution measurements in the O2 A-band.”
    “Two different population branches are apparent in the scattergram of the pathlength versus cloud optical depth; we attribute these to 1) single layer cases exhibiting small variations of pathlength enhancement over large optical depth ranges; and 2) multiple layer cases with large variances of enhanced photon pathlengths.”

    “The top panel in Figure 4 shows the time series of mean photon pathlength and cloud optical depth on a day where the pathlength shows much greater variance. Note that this variance is large even for the optical depth > 50 measurements, that occur only after 18:00 Universal Time Coordinates (UTC), where by eye the two seem strongly correlated at the scale of the top panel. Our attribution of the atmospheric state is not certain; we believe this case has a thin and varying upper layer cloud over low stratus. The large pathlength variations then occur due to multiple transits between the layers in cloud-free air that does not contribute to the cloud optical depth.”

    The incremental path length differences caused by cloud scattering, inferred from the changes in O2 alpha band absorption, and shown in their figure 4, varied from ~ 10% to 250% longer. IR emissions from the ground at wavelengths which CO2 absorb would likewise experience a longer effective path length to the TOA and larger absorption.

    Measuring and modeling this is complicated by such things as nonlinear scattering effects by cloud particles sizes near the CO2 absorption wavelengths, the relative distribution of cloud particle density versus atmospheric pressure, and the vertical profile of cloud density.

    Comment by Brian Dodge — 14 Dec 2010 @ 1:28 PM

  157. Terry (144) – “the authors also found that lack of cloud cover caused a positive SST anomaly ie a -ve feedback”

    A lack of cloud cover would be a warming influence. Added to El Nino warming, it would constitute a positive feedback. I do agree that their model involves a series of changing phenomena, but I didn’t see any clear negative feedbacks among them.

    Comment by Fred Moolten — 14 Dec 2010 @ 1:49 PM

  158. BD 153,

    There is almost no scattering at infrared wavelengths. The only situation where I can remember it being a major factor is on Venus.

    Comment by Barton Paul Levenson — 14 Dec 2010 @ 5:30 PM

  159. I’m just wondering about Venus. Didn’t it have oceans, and didn’t they vaporize away, and in the process, didn’t the water vapor (some in form of clouds) contribute to the increasing warming? Or does this not relate at all to the discussion here.

    Comment by Lynn Vincentnathan — 14 Dec 2010 @ 5:36 PM

  160. Brian Dodge (153), very interesting. It’s hard to see a big effect given the propensity of IR absorption by CO2 rather low in the atmosphere. But it does give food for thought, and, technically at least, forcing (alone) does seem to be affected directly by clouds. Thanks.

    Comment by Rod B — 14 Dec 2010 @ 5:39 PM

  161. Gavin:

    [Response: No idea what you are referring to. A global annual mean radiative forcing from the sun (= delta(TSI)/4*0.7 ) has almost exactly the same effect as the same amount of CO2 related forcing.]

    Apparently not. If that were true, then the total warming expected from a doubling of CO2 would only be about 0.6 C and not the 3 degrees C predicted. The average amount of positive feedback for each 1 W/m^2 power from the Sun is only about 60% – meaning each 1 W/m^2 of albedo adjusted power coming in from the sun is amplified to about 1.6 W/m^2 at the surface due to the presence of greenhouse gases and/or clouds in the atmosphere. If an additional 2 W/m^2 of power from a doubling of CO2 is treated the same as 2 W/m^2 of additional power from the Sun, the temperature increase would only be about 0.6 C (2 W/m^2 x 1.6 = 3.2 W/m^2 – at 288K a 3.2 W/m^ increase from 390 W/m^2 to 393.2 W/m^2 equals a 0.6 C rise via Stefan-Boltzman).

    [Changes related to the orbit which impacts seasonal insolation are a whole other kettle of fish (cf. the ice ages), but don't really fall into a neat radiative forcing argument. - gavin]

    Why? Are you saying the perihelion-aphelion insolation changes are not “forcing” the climate?

    Comment by RW — 14 Dec 2010 @ 7:25 PM

  162. Patrick:

    [If you held Earth at perihelion distance for several decades (or shrunk the semimajor axis to equal the present perihelion distance), you would get that warming (assuming your math is correct; actually for the same forcing efficacy, the warming in deg C or K would be a somewhat smaller than the value of forcing in W/m2; anyway, I’m not sure if I’m remembering the Earth’s orbit’s eccentricity correctly). It takes time to reach equilibrium because of the heat capacity of the oceans.]

    Then how do you explain the relatively large and fast seasonal temperature changes that occur in each hemisphere every year? The seasonal hemispheric fluctuations in radiative forcing that occur are astronomically greater than the measly 1.85 W/m^2 that will come from a doubling of CO2. If what you’re saying is true – that the heat capacity of the oceans take decades to reach equilibrium, we wouldn’t see anywhere near the seasonal variability that occurs each year.

    [The forcing of a doubling of CO2 is ~ 3.7 W/m2; the 1.85 W/m2 net forcing you refer to would be the remaining disequilibrium after the climate warms approx. halfway to new equilibrium.]

    No, the 1.85 W/m^2 is the amount of absorbed power that is radiated downward toward the surface, the other half is radiated upward out to space in the same general direction it was already headed.

    Comment by RW — 14 Dec 2010 @ 7:57 PM

  163. Fred #154
    Yes you are quite right, and I mis-read the section on heat fluxes w.r.t. different cloud ages. On reflection it is no surprise that the model shows this, as it uses the same cloud feedback regime as most of them. What is interesting tho is that the ENSO events can be simulated purely on an atmospheric basis, which must significantly alter the contribution that atmospherics have in the GCMS.

    Comment by Terry — 14 Dec 2010 @ 8:37 PM

  164. RW,
    What you really need is Tamino’s post, entitled “Not Computer Models,” where he describes a 2-box model, with one box, representing the atmosphere and reacting on a timescale of about a year, and a second box interacting with the first with a timescale of about 30 years. Seasonal changes affect primarily the smaller box (the atmosphere). It ain’t that tough.

    Comment by Ray Ladbury — 14 Dec 2010 @ 9:01 PM

  165. BPL (155), so while Brian Dodge’s reference (153) might be correct in that scattering of IR increases the path length and hence affects the forcing, you’re saying that very little (nearly none) IR is subject to scattering by atmospheric molecules and therefore the point of the assertion is moot — correct?

    Comment by Rod B — 14 Dec 2010 @ 11:39 PM

  166. I think I’m missing something pretty basic to the discussion. Maybe someone could help me out? Sometimes, it sounds like the claim at stake is whether increases in temperature are associated with increases (or decreases) in cloud cover — that’s the way Spencer puts it on his blog. (I use “associated with” here so as not to beg the causal question.) On this reading, the effect of a unit of cloud cover is constant (more or less), and the question is just whether warming positively or negatively causes cloud cover, right?

    Other times, it sounds like the claim at stake is whether increases in temperature are associated with increases (or decreases) in the influence of cloud cover on temperature — that’s the way I read Dessler. On this reading, the issue isn’t about cloud *cover* at all but about how clouds trap or reflect energy at different temperatures.

    Which claim is at stake or is it a hybrid of the two or something else entirely?

    Comment by Mostly Anonymous — 15 Dec 2010 @ 3:40 AM

  167. RW 161: Why? Are you saying the perihelion-aphelion insolation changes are not “forcing” the climate?

    BPL: Those forcings balance every year, and the climate has a thermal equilibrium measured in months, so in the long run, their forcing is irrelevant. Radiative forcing for changing the climate requires a secular trend, and giving it long enough to have a significant effect.

    Comment by Barton Paul Levenson — 15 Dec 2010 @ 6:02 AM

  168. 162 (RW),

    Seasonal changes are far more a result of the change in angle of incidence and duration of insolation (winter = fewer hours, summer = more hours) which result from the earth’s axial tilt. The total insolation received by a hemisphere can therefore vary greatly (far in excess of the aphelion/perihelion difference), causing great temperature swings with the seasons, but the total insolation of the planet as a whole remains constant (with the exception of the 14 W/m^2 to which you refer).

    The main points are that:

    1) The dramatic seasonal warming that you see is a result of axial tilt, not distance from the sun.

    2) The warming you see in one hemisphere is countered by cooling in the other; it’s not exactly proportional, because of the differences in land masses and resulting snow/ice cover in the two hemispheres, but it’s close enough. You’re not talking about global warming or cooling (much), but rather hemispheric warming/cooling, which is a quite different animal.

    3) The 14W/m^2 that you are talking about is relatively short lived (3 months, and most of that at less than 14W/m^2?), so while the hemispheres may warm/cool dramatically as a result of huge changes in insolation due to axial tilt (24 hours of daylight at one pole versus 0 hours of daylight at the other, in the extreme case), the planet as a whole does not have time to react to the change.

    Comment by Bob (Sphaerica) — 15 Dec 2010 @ 4:53 PM

  169. BPL “There is almost no scattering at infrared wavelengths. ”

    There are lotsa cloud particles in the 10-30 micron size[1], which I would expect to scatter infrared in the important wavelengths strongly[2] – Mie scattering, resonance effects, and the high dielectric constant of water. The IR absorption and thermal emission of water and ice will overlap some of the CO2 lines, further complicating analysis.
    Unfortunately http://isccp.giss.nasa.gov/climanal9.html “Effects of Clouds on Longwave Fluxes” “…is currently under construction.”

    [1] http://isccp.giss.nasa.gov/cloudtypes.html
    “The standard ISCCP products assume that clouds warmer than 260 K are liquid clouds composed of spherical droplets with an effective radius of 10 microns and that colder clouds are ice clouds composed of crystals with a fractal shape (aspect ratio unity) that have an effective radius of 30 microns. ”
    [2] http://lasp.colorado.edu/~bagenal/1010/graphics/earth_ir_emission.gif

    Comment by Brian Dodge — 15 Dec 2010 @ 8:57 PM

  170. Barten:

    RE: [BPL: Those forcings balance every year, and the climate has a thermal equilibrium measured in months, so in the long run, their forcing is irrelevant. Radiative forcing for changing the climate requires a secular trend, and giving it long enough to have a significant effect.]

    I thought the climate has a thermal equilibrium that takes decades, not months? That’s what was claimed a few posts back by Patrick (and a think a few others). So which is it – months or decades?

    If the “significant effects” of changes in radiative forcing take so long (i.e. months or decades), then why do we see such wide temperature swings from day to night, for example?

    Comment by RW — 15 Dec 2010 @ 9:40 PM

  171. Bob,

    RE:[Seasonal changes are far more a result of the change in angle of incidence and duration of insolation (winter = fewer hours, summer = more hours) which result from the earth’s axial tilt. The total insolation received by a hemisphere can therefore vary greatly (far in excess of the aphelion/perihelion difference), causing great temperature swings with the seasons, but the total insolation of the planet as a whole remains constant (with the exception of the 14 W/m^2 to which you refer).]

    I never claimed or implied otherwise.

    RE:[The main points are that:

    1) The dramatic seasonal warming that you see is a result of axial tilt, not distance from the sun.

    2) The warming you see in one hemisphere is countered by cooling in the other; it’s not exactly proportional, because of the differences in land masses and resulting snow/ice cover in the two hemispheres, but it’s close enough. You’re not talking about global warming or cooling (much), but rather hemispheric warming/cooling, which is a quite different animal.]

    Why a different animal, fundamentally? The seasonal changes are a response to changes in radiative forcing – are they not? In fact, they are a response to a far, far larger change in radiative forcing than what would come from a doubling of CO2, yet the response is very quick – certainly not multiple months, otherwise the coldest or warmest temperatures wouldn’t occur until several months after the maximum angle of the tilt. There is a delay, but it’s only about one month.

    RE: 3) The 14W/m^2 that you are talking about is relatively short lived (3 months, and most of that at less than 14W/m^2?), so while the hemispheres may warm/cool dramatically as a result of huge changes in insolation due to axial tilt (24 hours of daylight at one pole versus 0 hours of daylight at the other, in the extreme case), the planet as a whole does not have time to react to the change.]

    Again, why not? Are you saying the +14 W/m^2 are not “forcing” the whole planet? I understand it would be proportionally less during the northern hemisphere winter than the southern hemisphere summer, but how is that relevant to the planet as whole?

    Comment by RW — 15 Dec 2010 @ 10:07 PM

  172. http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%281999%29012%3C0159%3APFCLSF%3E2.0.CO%3B2
    Chou, Ming-Dah, Kyu-Tae Lee, Si-Chee Tsay, Qiang Fu, 1999: Parameterization for Cloud Longwave Scattering for Use in Atmospheric Models. J. Climate, 12, 159–169.

    “With the scaling approximation, radiative transfer equations for a cloudy atmosphere are identical with those for a clear atmosphere, and the difficulties in applying a multiple-scattering algorithm to a partly cloudy atmosphere (assuming homogeneous clouds) are avoided. The computational efficiency is practically the same as that for a clear atmosphere. The parameterization represents a significant reduction in one source of the errors involved in the calculation of longwave cooling in cloudy atmospheres.”

    (Cited By many; see that list for mention of GISS Model E)

    Comment by Hank Roberts — 15 Dec 2010 @ 11:07 PM

  173. Re 162 RW Then how do you explain the relatively large and fast seasonal temperature changes that occur in each hemisphere every year? The seasonal hemispheric fluctuations in radiative forcing that occur are astronomically greater than the measly 1.85 W/m^2 that will come from a doubling of CO2. If what you’re saying is true – that the heat capacity of the oceans take decades to reach equilibrium, we wouldn’t see anywhere near the seasonal variability that occurs each year.

    You answered part of your own question: the seasonal forcing is much larger. (And actually, global circulation would tend to reduce the seasonal cycle (heat flux from summer to winter) whereas perihelion-aphelion differences have a global effect.) Also, compare seasonal variations over land to over the ocean. Also, when ice forms over the ocean it allows the air above to cool without as much heat flux from the water. Also, feedbacks won’t be the same everywhere.

    the 1.85 W/m^2 is the amount of absorbed power that is radiated downward toward the surface, the other half is radiated upward out to space in the same general direction it was already headed.

    No, radiative forcing is defined as a change in a flux (per unit area) – in this context, defined as the change in net downward flux (per unit area) (change in net downward = change in downward minus change in upward) (in this case, at the tropopause level after stratospheric adjustment). It is not the total increase in emission from the atmosphere (which is not in general evenly divided between upward and downward fluxes – the atmosphere is not isothermal and for that matter, water vapor and clouds are not evenly distributed over the mass of the atmosphere, or even just the troposphere).

    Comment by Patrick 027 — 15 Dec 2010 @ 11:19 PM

  174. “Then how do you explain the relatively large and fast seasonal temperature changes that occur in each hemisphere every year? ”

    Because of the tilt of the earth, the amount of sunlight energy hitting my yard at noon varies by a factor of ~2 between summertime when the sun is ~12.5 degrees from directly overhead, and wintertime, when it only gets to about 30.5 degrees above the horizon.The January – July temperature difference is about 40 deg F. Dallas has a 1.9 summer-winter ratio, and a 41 degree temp range. Miami has a 1.5 ratio, and a 20 degree temperature difference; Fairbanks has an insolation ratio of 7.1, and a 73 degree Jan-July temperature difference. Quito ecuador, near the equator, has an average monthly temperature of 20-21 degrees centigrade year round, There’s a definite trend here, but altitude, proximity to large bodies of water, being windward or leeward of mountain ranges all have additional effects.

    Comment by Brian Dodge — 16 Dec 2010 @ 12:38 AM

  175. Re RW – large diurnal (day-night) temperature swings – you don’t see that over the ocean, it’s a land thing (and reduced at lower elevations, greater humidity or cloud cover, and affected by surface characteristics). And it’s from a huge forcing (hundreds of W/m2).

    (PS I think it should be easier to get larger temperature swings relative to forcing for localized areas over shorter time periods, when the atmospheric circulation hasn’t had time to redistribute the effect. Over time, oceanic heat capacity acts on temperature over land.)

    Comment by Patrick 027 — 16 Dec 2010 @ 12:42 AM

  176. RW 170,

    For seasons it’s months. For daily local temperatures it’s hours. For climate it’s years. Different processes on different time scales.

    Comment by Barton Paul Levenson — 16 Dec 2010 @ 6:40 AM

  177. 171 (RW),

    Are you asking a legitimate question, because you are confused and are trying to puzzle out the flaw in your own logic, or are you trying to “put another nail in the coffin of AGW belief” with your own dramatically novel insight?

    If it’s the latter, you should consider that no one on the planet has ever tried your argument (that I know of), including real “skeptic” scientists like Lindzen and Spencer. No one has any issue with the forcing difference between aphelion and perihelion or the seasons versus CO2, so if you think you’ve hit on something dramatically insightful, you should extend yourself pretty far (with a truly skeptical point of view) in trying to figure out where maybe you have misunderstood things that the rest of the world has gotten right, rather than the dramatically Galilean opposite (i.e. you’re right, and the whole civilized world is wrong).

    [And mind you, even Galileo was not alone. He was in fact preceded by Copernicus in his beliefs, and shared them with a fair number of educated contemporaries. His distinction was in having the courage to openly, publicly push it. But it was primarily the theologists and philosophers who where offended and threatened by his position (the equivalent of today's economic reactionaries and fossil fuel interests), and not the people who were more learned in mathematics. As a note, "scientists" did not exist at the time, so "philosophers" were the scientists, or rather, there was no clear distinction between the two, except, perhaps, in each individual's true nature.]

    If you honestly want to know where your logic is flawed, kindly do some research, think things through further, and when you think you’ve gone as far as you can alone, ask again about any particulars and you will get help here.

    If you think you’ve somehow found a salient point that no one can possibly refute, kindly do some serious research, seriously think things through, but don’t expect any responses here much beyond frustration and slowly building annoyance. It’s a non-starter.

    Comment by Bob (Sphaerica) — 16 Dec 2010 @ 11:15 AM

  178. Possibly the least OT for any current thread–I’ve got a new article up today touching upon some of the basic science we’re discussing here, and would appreciate corrections/criticisms/suggestions from any kind (and astute!) souls willing to take a look:

    http://hubpages.com/hub/Water-Is-A-Dancer

    (Cross-posted at “Open Mind.”)

    Comment by Kevin McKinney — 16 Dec 2010 @ 12:40 PM

  179. Regarding Comment 106 by William “Although there was a correlation between GCRs and low-level cloud cover until about 1991, after that point the correlation broke down (Laut 2003) and cloud cover began to lag GCR trends by over 6 months, while cloud formation should occur within several days (Yu 2000).”

    FYI, following study suggests a small but “statistically robust relationship” between short-term GCR flux changes and rapid mid-latitude cloud decreases over the past 20 years. Correlation persists.

    Cosmic rays linked to rapid mid-latitude cloud changes – Laken, Kniveton, Frogley (2010)
    http://www.atmos-chem-phys.net/10/10941/2010/acp-10-10941-2010.pdf

    Comment by Doc Savage Fan — 16 Dec 2010 @ 1:36 PM

  180. re clouds etc., Tenney Naumer sent me this and I’ve been feasting on it (visually) from time to time.

    For a relative layperson, the demonstration of the obvious: that light and dark is a sine wave, is striking here as well.

    Comment by Susan Anderson — 16 Dec 2010 @ 3:50 PM

  181. Seems to Eli that a lot of the problem here (and with RS) is limiting El Nino to being a purely temperature effect. There are major changes in wind and sea currents.

    Comment by Eli Rabett — 16 Dec 2010 @ 5:28 PM

  182. To add to the various replies to RW, you can quantify the seasonal forcing due to the change in sun angle at a typical location as 200 W/m2 in the daytime, or 70 W/m2 diurnally averaged.. This is much bigger than the elliptical orbit effect of 14 W/m2.

    Comment by Jim D — 16 Dec 2010 @ 10:37 PM

  183. Re my 175 (re RW)
    (PS I think it should be easier to get larger temperature swings relative to forcing for localized areas over shorter time periods, when the atmospheric circulation hasn’t had time to redistribute the effect. Over time, oceanic heat capacity acts on temperature over land.)

    I could have explained this better:

    If you have some heat capacity C and apply a change in forcing RF, equilibrium temperature changes sharply, but the actual temperature must change gradually, decaying exponentially on a time scale proportional to C (for climate change, the time scale is proportional to C * climate sensitivity – because climate sensitivity is higher when a given temperature change causes a smaller reduction in the imbalance in the heat fluxes).

    If you only apply a forcing to some small heat capacity, then it may at first decay toward the new equilibrium at a fast rate; however, if heating or cooling changes can spread out from this heat capacity to other heat capacity (atmospheric and oceanic circulation), then as the time progresses to a scale where this spreading is significant, the decay toward the new equilibrium slows, and actually the temperature will not reach a local equilibrium because a larger system is responding to the localized forcing.

    Farther to mine and other’s points – the diurnal and seasonal forcings are quite large; the responses are large. If you (RW) were trying to construct an argument based on the idea that these responses are large because they are near equilibrium, you’d be wrong. Consider that the polar winter night, or any night time, the local equilibrium temperature would hover just above absolute zero (that’s -273.15 deg C). It never gets anywhere near this cold, even in Antarctica. Yes, in part because of atmospheric and oceanic circulation (Antarctica, being an snow/ice surface, I would guess might get quite a bit closer to absolute zero in the absence of heat fluxes from lower latitudes, but I’m not sure just how close – you’d need to take the thermal conductivity and heat capacity of the surface material into account) – so this observation doesn’t entirely suffice to illustrate the effect of heat capacity alone (although it would be hard for circulations to transport heat if the material had no heat capacity – the air reaching Antarctica in winter would be much colder if it reached such a locally-determined equilibrium; the heat capacity reduces the amount of cooling that can occur during the time it takes for circulation to transport material) – but it does illustrate that you’re (RW) observations do not suffice to make a case for small climate sensitivity – or larger climate sensitivity (after all, you suggested the lack of response to perihelion would suggest low climate sensitivity (it would if heat capacity were much smaller), and then argued that heat capacity must be small because of the large responses to diurnal and seasonal forcings (which would suggest large climate sensitivity if the forcings were smaller or the heat capacity acting on those scales were larger).

    Comment by Patrick 027 — 17 Dec 2010 @ 12:49 AM

  184. @ Kevin McKinney — 16 December 2010 @ 12:40 PM
    “…, when “normal” rain containing natural carbonic acid falls upon silicon-containing sedimentary rocks…”

    The important processes for geological sequestration are more complex. The important source rocks are volcanic/igneous, and the important components are the various complex silicates contained therein.

    Basalt/Gabbro – pyroxene, plagioclase feldspar, amphibole, and olivine
    -http://en.wikipedia.org/wiki/Pyroxene
    -http://en.wikipedia.org/wiki/Feldspar
    -http://en.wikipedia.org/wiki/Amphibole
    Andesite/Diorite – feldspar, biotite, hornblende, pyroxene
    -http://en.wikipedia.org/wiki/Hornblende
    -http://en.wikipedia.org/wiki/Mica
    Dacite/Granodiorite – plagioclase feldspar with biotite(mica), hornblende, pyroxene, and quartz
    Rhyolite/Granite – quartz, alkali and plagioclase feldspar, biotite and hornblende

    Physical weathering breaks up these rocks into fine particles(clays), and concurrent dissolution and chemical weathering allows the replacement of the SiO2 anion with the carbonate anion. The solid metal-(aluminum)-silicates plus CO2 gas are transformed into solid (or dissolved) metal carbonates, and solid (aluminum)-silicates, or silica. – http://en.wikipedia.org/wiki/Kaolinite

    The source rocks aren’t very soluble, but the large surface area created by weathering allow the reactions to sequester CO2 on geologic time scales. The most important metal is calcium, but magnesium and iron also play a role. The sodium and potassium compounds largely remain in solution, although natural evaporite deposits of sodium carbonates occur. – http://en.wikipedia.org/wiki/Sodium_carbonate

    Comment by Brian Dodge — 17 Dec 2010 @ 4:28 PM

  185. @177 Bob (Sphaerica):
    …you should extend yourself pretty far (with a truly skeptical point of view) in trying to figure out where maybe you have misunderstood things that the rest of the world has gotten right, rather than the dramatically Galilean opposite (i.e. you’re right, and the whole civilized world is wrong).

    Well put.

    Cranks, of course, never consider this preliminary step before unleashing their brilliant insights on an astonished world. RW’s next effort will no doubt reveal whether he has simply overlooked this elementary precaution, or dismisses it as unnecessary in light of the obvious genius of his ideas.

    Comment by Adam R. — 18 Dec 2010 @ 10:30 AM

  186. Dr Dessler,

    Thank you for taking the time to explain your results to interested non-scientists.

    You write:

    quote
    But aerosols’ radiative impact is not expected to
    correlate with DTs, so the effect of aerosols is to
    add uncertainty to the cloud feedback calculation
    but should not introduce a bias.
    unquote

    My particular interest is aerosols and the effects of pollution on their production. I can think of two mechanisms which might alter their numbers during ENSO events. Varying windspeeds will change the number and vigour of breaking waves — by an amount which is presumably quantifiable — and stratification will change phytoplankton populations and hence DMS levels in the ocean/atmosphere boundary layer.

    Both mechanisms will be correlated with SST changes to some extent — again by an amount which is presumably quantifiable. My guess is lower windspeeds and/or higher SSTs would lead to fewer aerosols, but I am, of course, open to actual measurements correcting that guess.

    Would accounting for these changes influence the conclusions of your paper re a possible bias? Are there any measurements of aerosol changes during ENSO events which could be plugged into your analysis?

    TIA.

    Julian Flood

    Comment by Julian Flood — 31 Dec 2010 @ 7:41 AM

Sorry, the comment form is closed at this time.

Close this window.

0.644 Powered by WordPress