Weekend reflections

Weekend Reflections is on again. Please comment on any topic of interest (civilised discussion and no coarse language, please). Feel free to put in contributions more lengthy than for the Monday Message Board or standard comments.

45 thoughts on “Weekend reflections

  1. Water vapour itself has a positive feedback. Clouds can have a positive or negative feedback.

    And clouds are made from water vapour. Your point?

    Or pick the last glacial maximum that gives the answer you want.

    Ah, that would explain why there is no variance in climate sensitivity estimates. Not.

  2. “And clouds are made from water vapour”

    Water vapour always has positive feedback. Water vapour may or may not produce clouds. Clouds may produce positive feedback, they may produce negative feedback. Net result: varying between a lot of positive feedback and not much feedback.

    “there is no variance in climate sensitivity estimates”

    Or we could just assume we’re lucky and we’ve scored the 15% chance that sensitivity is less than 2.2 degrees C/CO2 doubling. You’ve got to ask yourself, do you feel lucky, well do ya?

  3. The scientific debate (on the central issue of the reality of AGW) has been over for some time. The public debate has also finished, in Australia at any rate. What’s left is the hardcore of committed delusionists, almost all of whom base their beliefs/claims on wishful thinking derived from rightwing ideology.

    Chris is obviously prepared to keep on educating. From my viewpoint though, the obvious prevalence of delusionism on the political right is now an asset, and there’s no reason to run it down.

  4. My 3 y.o can come up with more convincing face saving excuses than that, JQ.

    I am not arguing against the reality of AGW. My argument is with the distortions used to manipulate public opinion and with the details: what is the sensitivity? What is the natural variation? How accurately are we measuring T? What are the consequences?

    And Chris is not educating, he is conceding the original point: water vapour (in its many forms) can have both positive and negative feedbacks, with the negative feedbacks from clouds particularly poorly understood. And 15% prob of sensitivity less than 2.2C? That we can be so certain.

  5. ProfQ: Agreed. The denialists (sorry delusionists) are descending into farce now. One only had to witness the audience questions after “swindle” was aired on the ABC to see the damage they’re doing to their cause.

    IMO, the fossil fuel lobby is running a cleverer strategy by accepting the science but claiming that only fossil fuels (cleaned up with CCS) can solve the problem.

  6. “water vapour (in its many forms) can have both positive and negative feedbacks”

    It’s highly misleading to state it that way. The positive feedbacks are way stronger than the negative feedbacks. A statement like the above creates the false impression in an unknowledgeable reader that the positive and negative feedbacks are comparable.

    “negative feedbacks from clouds particularly poorly understood”

    They don’t have to be particularly well understood to know that that the positive feedback is much stronger than the negative feedback.

    “And 15% prob of sensitivity less than 2.2C? That we can be so certain.”

    No one said there is zero uncertainty in the 15% figure. You can refer to Annann’s paper if you want to know the uncertainty of the uncertainty. Yet mugwump appears to think it could be somewhere near 100%. (Why do I keep thinking I am being fed hypocrisy by mugwump?) It’s pretty obvious who is using distortions to manipulate public opinion. It’s the same people who say they want to argue the details but for some reason they never manage to argue the details with people who work (in their jobs) on the details and who regularly publish papers on the details.

  7. It’s highly misleading to state it that way. The positive feedbacks are way stronger than the negative feedbacks.

    Clouds are responsible for approximately half of the Earth’s albedo. That’s a large, poorly understood “negative feedback”. Are you confident the GCMs model cloud formation sufficiently well to determine that albedo changes are negligible?

    Even without natural albedo increases, at least some scientists think it might be possible to artificially boost cloud albedo enough to mitigate the effects of increased CO2.

    No one said there is zero uncertainty in the 15% figure. You can refer to Annann’s paper if you want to know the uncertainty of the uncertainty. Yet mugwump appears to think it could be somewhere near 100%.

    Why don’t you tell me what Annann thinks is the uncertainty of the uncertainty? I suspect the true uncertainty of the uncertainty is closer to 100% than 0%, mainly because there still seem to be a lot of unknown unknowns.

  8. “Clouds are responsible for approximately half of the Earth’s albedo.”

    Again, a highly misleading statement. The issue is the change, not the starting value. Check this page to see estimates of the various types of feebacks. Even if you doubled the biggest cloud negative feedback (short wave cloud optical properties) and made the brave assumption that the related cloud positive feedbacks (long wave cloud optical properties, short wave cloud fraction) did not increase, the total cloud feedback would still be positive. And that’s without even considering the other positive feedbacks.

    “at least some scientists think it might be possible to artificially boost cloud albedo enough to mitigate the effects of increased CO2”

    “scientists”. Hmm, I guess a few scientists might present papers at an energy engineers conference but I can’t be bothered looking for them.

    “I suspect the true uncertainty of the uncertainty is closer to 100% than 0%”

    OK, you suspect the probability of sensitivity less than 2.2C might be 30%. Waiting for you to pull the trigger on the 10 bullet gun loaded with 7 bullets.

  9. “Clouds are responsible for approximately half of the Earth’s albedo.�
    Again, a highly misleading statement. The issue is the change, not the starting value.

    It may have been a misleading statement if I hadn’t followed up with:

    “Are you confident the GCMs model cloud formation sufficiently well to determine that albedo changes are negligible?”

    You then refer me to a web page that discusses GCM cloud models in great detail, but with no empirical comparison against real cloud formation (unless I missed something). While interesting, it does not constitute a validation of the cloud models.

    Hmm, I guess a few scientists might present papers at an energy engineers conference but I can’t be bothered looking for them.

    Uhuh. Just as you can’t be bothered reading what I write before claiming I am misleading.

  10. “Are you confident the GCMs model cloud formation sufficiently well to determine that albedo changes are negligible?â€?”

    The thing that matters is the total feedback from clouds (and the total overall feedback), not just part of it. The total feedback from clouds predicted by GCMs ranges from neutral to strongly positive. In addition to this, water vapor plus lapse rate feedback is strongly postive. If you want to bet that every last GCM is completely wrong and that total cloud feedback is actually strongly negative go ahead. But in any case you are ignoring the estimate of sensitivity derived from 3 observations: (1) 20th century warming; (2) volcanic cooing; and (3) the last glacial maximum. If you want to pull the trigger on that 10 bullet gun loaded with 7 bullets then go ahead, I’m waiting. Maybe you could even be bothered to read a scientific paper.

  11. The total feedback from clouds predicted by GCMs ranges from neutral to strongly positive.

    The fact that estimates of total cloud feedback have such a broad range indicates the models are still very poorly understood, which is exactly my point.

    On (1) (20th century warming): Would that be Urban or Rural? Because the oft-quoted IPCC mantra that UHI is insignificant is looking highly suspect.

    And your 7-bullet analogy is off-the mark. By “100% uncertainty in the 15% uncertainty” I meant the 15% could be anything, not that it could be up to 30%.

    How many scientific papers should I read, Chris? A rough estimate puts the total so far at around 1500.

  12. “The fact that estimates of total cloud feedback have such a broad range indicates the models are still very poorly understood”

    It means the phenomenon is not very accurately understood but doesn’t change the result that the overall feedback is at least strongly positive.

    “On (1) (20th century warming): Would that be Urban or Rural?”

    Rural over land. Sea surface temperature over ocean (70% of earth’s surface). Could use satellite figures as well.

    “Because the oft-quoted IPCC mantra that UHI is insignificant is looking highly suspect.”

    What IPCC statement are you referring to? BTW, speaking of McIntyre, did you ever work out how, in spite of being a “lousy proxy�, the Bristlecone-dependent proxy network (i.e. the “1400″ network) gives very good agreement with more extensive networks that don’t go back as far into the past. McIntyre tried to argue at one point that the Bristlecone series is no good because there is a well-understood CO2-growth bias in the last 200 years but gave up and jumped to another argument. Whenever pursued, his arguments get dropped and a new one is thrown up.

    Also BTW, the significance of the hockeystick graph is not that it’s evidence for AGW. Its significance relates to how substantial AGW is compared with natural variation. If natural variation was much larger than AGW, AGW would be insignificant.

    “And your 7-bullet analogy is off-the mark.”

    Why don’t you read the paper and find out and repeat your opinion to James Annann.

    “How many scientific papers should I read?”

    The one that matters.

  13. This is getting tedious.

    You say:

    The total feedback from clouds predicted by GCMs ranges from neutral to strongly positive.

    Then you say:

    the overall feedback is at least strongly positive.

    Which is it? “Neutral to strongly positive” or “at least strongly positive”?

    What IPCC statement are you referring to?

    IPCC draft AR4, chapter 3, page 10, line 23:

    rural station trends were almost indistinguishable from series including urban sites (Peterson, 2003)

    Read the whole paragraph. Utter fiction in light of McIntyre’s recent reanalysis.

    BTW, speaking of McIntyre, did you ever work out how, in spite of being a “lousy proxy�, the Bristlecone-dependent proxy network (i.e. the “1400″ network) gives very good agreement with more extensive networks that don’t go back as far into the past

    Specific reference please.

    Also BTW, the significance of the hockeystick graph is not that it’s evidence for AGW. Its significance relates to how substantial AGW is compared with natural variation. If natural variation was much larger than AGW, AGW would be insignificant.

    I agree, and I have said as much at least once on this blog.

    Why don’t you read the paper and find out and repeat your opinion to James Annann.

    I’ve read the paper. It’s an ok paper, but does read like Annan just discovered Bayesian Statistics and got all excited applying it to GCM predictions. His estimates are still only as good as the models and the underlying data.

  14. “”the overall feedback is at least strongly positive.””

    “Which is it? “Neutral to strongly positiveâ€? or “at least strongly positiveâ€??”

    Overall means all the feedbacks, not just cloud feedbacks.

    “”“Because the oft-quoted IPCC mantra that UHI is insignificantâ€?””

    “”What IPCC statement are you referring to?””

    “IPCC draft AR4, chapter 3, page 10, line 23:”

    “”rural station trends were almost indistinguishable from series including urban sites (Peterson, 2003)””

    That’s interesting, although GISS don’t use urban sites anyway for calculating long term trend.

    “is looking highly suspect. Utter fiction in light of McIntyre’s recent reanalysis.”

    Sure, if you and McIntyre say so. BTW, “urban sites” does not mean the same as “all urban sites”.

    “”BTW, speaking of McIntyre, did you ever work out how, in spite of being a “lousy proxyâ€?, the Bristlecone-dependent proxy network (i.e. the “1400″ network) gives very good agreement with more extensive networks that don’t go back as far into the past””

    “Specific reference please.”

    https://johnquiggin.com/index.php/archives/2007/07/12/delusionists-demolished#comment-192638

    “”Why don’t you read the paper and find out and repeat your opinion to James Annann.””

    “I’ve read the paper. It’s an ok paper, but does read like Annan just discovered Bayesian Statistics and got all excited applying it to GCM predictions.”

    Are you sure you read the paper? You seem to have an obsession with GCM predictions. Annann did not use GCM predictions to calculate his sensitivity estimate.

    “His estimates are still only as good as the models and the underlying data.”

    As I said, he didn’t use the GCMs for his estimate. As for depending on underlying data, well, that’s the problem with science isn’t it?

  15. So UHI is not a problem until it is, then it doesn’t matter.

    The hockeystick was correct until it wasn’t, then it didn’t matter.

    The surface temperature record was correct until it wasn’t, but now it doesn’t matter either.

    A blog comment link is not a scientific reference.

    Annan used climate models for his estimates. Reread the paper, Chris.

  16. “So UHI is not a problem until it is, then it doesn’t matter.”

    More like, we can leave out the UHIs until we know they don’t matter.

    “The hockeystick was correct until it wasn’t, then it didn’t matter.”

    More like, the hockstick was and is correct but for some insignificant errors and has been repeatedly confirmed. It still matters.

    “The surface temperature record was correct until it wasn’t,”

    More like, one calculation of the surface temperature record was accurate enough and is still accurate enough.

    “but now it doesn’t matter either.”

    More like single years don’t matter and never did and the US is not very significant and never was.

    “A blog comment link is not a scientific reference.”

    A blog comment shows when another blog commenter disappears from an argument and that the disappearer has zero substance by not responding to arguments that included scientific references.

    “Annan used climate models for his estimates.”

    As in, some of his estimates. Here’s a hint, Annann said in the introduction, “Recently, there has been an increasing focus on the potential of observationally-derived constraints to generate a more objective estimate of climate sensitivity.” Gee I wonder where he might go with a statement like that.

  17. “More like, we can leave out the UHIs until we know they don’t matter.”

    Chris, the IPCC claimed no significant difference in warming trends between urban and rural. That is turning out to be false. That matters, especially as a lot of the numbers used to estimate the surface temperature are partially contaminated with urban trends.

    “More like, the hockstick was and is correct but for some insignificant errors and has been repeatedly confirmed. It still matters.”

    One of those supposedly insignificant errors is the claim that the MWP was not a global phenomenon. Turns out the hockeystick does not establish that, precisely because Mann and his cohorts are lousy statisticians. That’s significant.

    “More like single years don’t matter and never did and the US is not very significant and never was.”

    It is more than single years in the US. The overall adjustment is negative – so warming has been far less pronounced there than previously thought. Politically, the unending mantra from the climatologists that we’re setting near-record after near-record in the US is also now false. That an error of such magnitude could slip through is also significant. As are the denials from the pontiff and his cardinals, and their continued refusal to release their source code.

    “A blog comment shows when another blog commenter disappears from an argument and that the disappearer has zero substance by not responding to arguments that included scientific references.”

    Just give me the scientific references Chris. Chapter and verse. The same courtesy I extended to you when pointing out false claims by the IPCC, and standard academic practice.

    “As in, some of his estimates. Here’s a hint, Annann said in the introduction,”

    So you’ve read Annan’s introduction. Now read the rest of the paper. If you get stuck with some of the symbols, give me a hoi and I’ll see if I can help you out.

  18. “the IPCC claimed no significant difference in warming trends between urban and rural.”

    Papers they referred to actually.

    “That is turning out to be false.”

    Sure it is. Don’t trust McIntyre to get every detail right. He has been known to be wrong before.

    “That matters, especially as a lot of the numbers used to estimate the surface temperature are partially contaminated with urban trends.”

    “A lot”, as in who?

    “One of those supposedly insignificant errors is the claim that the MWP was not a global phenomenon.”

    Funny, I don’t see any mention of MWP in their supplementary information.

    “Turns out the hockeystick does not establish that, precisely because Mann and his cohorts are lousy statisticians.”

    Sure, if McIntyre says so. Why not just say the claim that the MWP is not global is false because Mann and his cohorts are lousy statisticians? The spuriousness of your argument would be clearer.

    “It is more than single years in the US.”

    You’ll forgive me for being distracted by all the crap about which year was the warmest in the US.

    “the unending mantra from the climatologists that we’re setting near-record after near-record in the US is also now false.”

    Where do you get this trash from mugwump? If I were you I’d seriously be questioning my sources. The words the NCDC uses are: “placed 1998 in a virtural tie with 1934 as the warmest year” and “2006 was the 2nd warmest year on record and nearly identical to the record set in 1998”. Where is the false statement?

    “That an error of such magnitude could slip through is also significant.” Stitching together long term records through changes in technique is an ongoing issue. Normally such changes attract a lot of attention but obviously they don’t get publicised sometimes. Like any process for establishing reliability, single points of failure are avoided in determining a temperature record, i.e. we don’t don’t go by just one record.

    “Just give me the scientific references”

    As if you’re in the habit of doing such. You could provide scientific references for your assertions I’ve copied below. Since you’re too lazy to look up what I referred to, I’ll have to repeat it here. From delusionists demoished:

    Start of quote.

    This is an old argument, but..

    mugwump: “The problem is, Mann’s hockeystick is not robust to removal of the Bristlecone series..�

    Actually, it is robust to the removal of the Bristlecone series as far back as 1450 (to 1428 if you want to do some more calculations). Indeed MBH99 freely admits that the hockeystick is not robust to removing this series before 1400.

    “and it turns out the Bristlecones are actually lousy temperature proxies.�

    According to Steve McIntyre. But somehow, in spite of being a “lousy proxy�, the Bristlecone-dependent proxy network (i.e. the “1400″ network) gives very good agreement with more extensive networks that don’t go back as far into the past. McIntyre tried to argue at one point that the Bristlecone series is no good because there is a well-understood CO2-growth bias in the last 200 years but gave up and jumped to another argument. Whenever pursued, his arguments get dropped and a new one is thrown up.

    “As for McIntyre’s credibility: call me old-fashioned, but for me it stands on the quality of his work.�

    Good joke. Love the irony.

    “Read his papers.�

    Have.

    “Read his blog.�

    Have.

    “He is very good at what he does.�

    Sure, if you say so.

    End of quote.

    “The same courtesy I extended to you when pointing out false claims by the IPCC”

    The courtesy didn’t extend to any scientific reference pointing out why claims by the IPCC were false, just some messing around by McIntyre.

    “So you’ve read Annan’s introduction.”

    Pity you can’t take the hint. That’s the problem when your credulousness interferes with your cognitive skill. Anyway, Annann says “By construction, our prior based on 20th century warming, and the two likelihood functions, are based on independent data and methods. We can therefore combine their information simply by multiplying all the functions together and renormalising.” The “two likelihood functions” referred to are from volcaic cooling and from the last glacial maximum. He also refers to these three in his figure 1: “Red solid line: combination of the three constraints” immediately after “Blue dashed line: 20th century warming (1,3,10). Blue dotted line: volcanic cooling (1.5,3,6). Blue dot-dashed line: LGM cooling (-0.6,2.7,6.1).”

  19. On Annan, reading back over the thread I said:

    His estimates are still only as good as the models and the underlying data.

    [because he uses both]

    You said:

    As I said, he didn’t use the GCMs for his estimate.

    To which I responded:

    Annan used climate models for his estimates.

    To which you responded:

    As in, some of his estimates.

    Which is what I meant. I missed that.

    Putting that to rest, there’s nothing left to argue over here, you’ve conceded all my points. Over-and-out.

  20. “On Annan, reading back over the thread I said:

    His estimates are still only as good as the models and the underlying data.

    [because he uses both]”

    You must have missed the point where I said:

    “But in any case you are ignoring the estimate of sensitivity derived from 3 observations: (1) 20th century warming; (2) volcanic cooing; and (3) the last glacial maximum.”

    I didn’t notice any meantion of CGMs in the estimate I was referring to. Please try to stick to the point.

    (spurious crap deleted)

    “Putting that to rest, there’s nothing left to argue over here, you’ve conceded all my points. Over-and-out.”

    The American-solution-in-Vietnam technique, declare victory and get out.

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