Discussion > Feedbacks and Forcings
shub
You haven't understood what I am trying to say.
Shub, you haven't understood what you are trying to say :-)
As for your re-imagining of the end of the conversation with K, well, as per, you have your own private version of reality. Stick with what make you happy. The rest of us will struggle on in the real world as best we can.
BBD
"And I never pretended to be a sceptic. I was and remain one."
Then why TF are you arguing with me about the "missing" heat, when all I'm doing is telling you that Trenberth, Peilke Sr, and Willis are discussing it and you have posted on here telling us the OHC is going up, while keeping back the important fact that it isn't going up nearly as fast as it should be according to Trenberth, who's concerned that if we can't find the missing heat the CAGW theory goes down the drain?
Yes you did pretend to be a sceptic, and no you're not.Yyou are as convinced of CAGW as I was convinced of Father Christmas when I was a child. The difference between us being that when I was told there wasn't a Father Christmas, much as I'd have like to have believed differently, there wasn't a "Skeptical Father Christmas" site I could go to in order to find peer reviewed papers that I could share with doubters, that supported my views as to his existence.
geronimo
Philip
Sorry for the disjointed reply. Anyway:
As you know, the argument starts by positing a low sensitivity, which means a smaller change in emissivity and hence a smaller increase in temperature to maintain the flow of outgoing energy. When the reply comes that a low sensitivity is incompatible with millennial variability, the argument would continue as above i.e. by discussing the mechanisms for variability.
But all the evidence is that sensitivity is at least moderately high (most likely value ~3C for 2xCO2 at equilibrium). So you are forced to *start* with a premise that is counter to the evidence. This isn't encouraging.
Then you have to re-do the common understanding of energy balance and climate variability. In the conventional model of the climate system, orbital forcing (modulating obliquity) is capable of terminating a glacial because of moderately high sensitivity enabled through net positive feedbacks. Everything (including the quasi-100ka astronomical pacing) fits. In the alternative view, this is (unphysically, to my mind) attributed to stochastic variation. Just because the patter 'looks similar' to very short period random walks means exactly nowt.
At decadal and millennial scales conservation of energy is improperly applied (albedo changes do not *persist* unless forcing is changed as the key variable components of planetary albedo (ice, snow, sea ice, surface vegetation and cloud) are *feedbacks* entrained by changes in forcing).
From my perspective, the mainstream position is coherent and the alternative as proposed here seems contrived and strained.
The strong impression I've always had in our conversations is that you have a prior commitment to the position that RF from CO2 is not going to cause significant warming.
This brings me to the key point, which of course is the elephant. What interests me much more than the novel view of physical climatology you find persuasive is *why*? Why won't you accept the mainstream scientific position on the climatological consequences of CO2 emissions? It is a much better fit with known climate behaviour than the alternative (in which it is marginalised), so why the consistent rejection?
Although this sounds like a discussion of the science, it doesn't actually *feel* like one. It feels as though there's an elephant in the room :-)
BBD
"(unphysically, to my mind) "
You lack the education required to evaluate the literature you reading. You shouldn't talk the way you do. And use a little less smilies in your writing.
shub
"key variable components of planetary albedo ...ice, snow, sea ice, surface vegetation and cloud ... are feedbacks"
Philip, I hope this type of statement illustrates to you the kind of superstitious bullshit descriptive climate science really is.
The basic subcomponents may be 'correct', or 'true' and in any case their action is immaterial of their understanding by us. What is really required of us, is to understand how they really get put together, or, fall in place.
BBD's statements in the post right above, show the limitations of the feedback/forcing paradigm.
BBD, for your information, a feedback - forcing paradigm ought not to depend, on the identification of a feeback factor as a feedback, and a forcing as a forcing, for its explanatory power. Think about that, instead of speculating on people's motives.
shub
shub
You lack the education required to evaluate the literature you reading. You shouldn't talk the way you do. And use a little less smilies in your writing.
As you have claimed before, but never demonstrated :-)
BBD
Oh, and that should be 'fewer' smilies ;-)
BBD
Well, I have asked you simple and fundamental questions in statistics and you cannot answer them to date. You did fill up your posts with a lot of words though. What further demonstration do you need?
Why listen to confident explanations of complex phenomena from someone whose grasp of the basics is at question?
shub
shub
This is getting boring again:
Why listen to confident explanations of complex phenomena from someone whose grasp of the basics is at question?
As you claim, but do not demonstrate on this thread. Why not wait for Philip's response? That would be less unnecessarily combative.
BBD
But all the evidence is that sensitivity is at least moderately high (most likely value ~3C for 2xCO2 at equilibrium).I'm glad you raised this point, BBD, because I have been looking for someone who has seen this "evidence" and can explain it to us.
I have been asking for years for the empirical evidence (as opposed to computer models and hand-waving) that the 1.2C increase which we are told (though without a great deal of evidence for that either) will result from a doubling of CO2 will be further enhanced by positive feedbacks.
If you have this evidence to hand I'm sure we would like to hear what it is.
Your continued assertion that it must be so because otherwise we'd still be in the last Ice Age is not evidence and your suggestion that the rest of us (in this case, Philip) are making assumptions is rather odd unless you are starting from established theory which you know as well as I do you cannot be, no empirical evidence for your conjecture having yet been produced.
On the subject of verbiage I am with shub. I have ploughed my way through your 7.28 post and almost lost the will to live twice. I finally concluded that you are trying to impress Philip by using big words. I shall watch the progress of that idea with interest!
Mike Jackson
I'm glad you raised this point, BBD, because I have been looking for someone who has seen this "evidence" and can explain it to us.I have been asking for years for the empirical evidence (as opposed to computer models and hand-waving) that the 1.2C increase which we are told (though without a great deal of evidence for that either) will result from a doubling of CO2 will be further enhanced by positive feedbacks.
Again? I don't have the strength :-) If you want to review the explanation, start at Aug 1, 2012 at 7:29 PM
And read on.
BBD
BBD,
I'm very grateful to you for expressing your views so clearly, but your points still do not explain the conflicting observational and theoretical evidence I've mentioned regarding natural variability.
1/ Although Milankovitch cycles are undoubtedly involved in glacial terminations, a cyclical mechanism is not able to explain the background spectrum.
2/ Reconstructions of acknowledged forcings are not able to explain the observed millenial scale variability because they do not scale appropriately.
3/ Climate models are found not to exhibit the observed scaling laws over time scales longer than a few decades.
These points are explored in numerous papers written by several different research groups, but as far as I know they have not so far been fully explained. My interest here is to try to explore with you the possible explanations.
Returning you if I may to the issue of cloud cover ... If I understand correctly, you think that cloud cover will only change as the result of a forcing and that any such change will only be maintained if the forcing is maintained. Let me say that this is exactly the kind of argument I want to hear about, because if correct it would explain very well why the average value for albedo should always be 0.3. However, I don't think it is correct. Cloud cover is governed to the greater extent by circulation patterns, and as far as I know these change because of non-linear interactions within the atmosphere and forcing is not required to either initiate or maintain them.
Philip Richens
In the alternative view, this is (unphysically, to my mind) attributed to stochastic variation. Just because the patter 'looks similar' to very short period random walks means exactly nowt.
I'm a little sad that you don't like my approach, because I actually have an enormous respect for your depth of knowledge. The fact is simply that for the kind of complex system that is the climate, everything I know (true, not a lot!) tells me to consider simple toy models; to use simple physical arguments; to keep on referring back to the data; to not be a slave to the data. I think you are mistaken to consider stochastic variation as an alternative to other perspectives. They are complementary, in my opinion. For example, even approaches that don't explain the long time-scale increase in variability still tend to accept that over short times it can be reasonable to approximate the weather by a white noise process. In the simple EBM, it is the interaction between this white noise and a store (the atmosphere) which leads to the random walk. A similar argument applies to the shallow ocean (longer time scale), and quite probably to the deep ocean and to ice cover as well. In other words, the pattern is likely to be ubiquitous. And if so, this would be a good thing, wouldn't it? Because it would give us insight into why the variability increases with time-scale.
I can’t remember if I’ve pointed you to this paper before? Not in the climate domain, I agree, but very relevant to the issues we have been discussing.
Philip Richens
Philip
Would you consider a force that produces a change over a tens of thousands of years in the climate system, a weak one or a strong one?
Similarly, would you consider a system that undergoes a change of state over hundreds of thousands of years, one that is extremely sensitive to change?
shub
In the 1950s and 60s (in the days before things like the Advertising Standards Authority and the Permissive Society) there used to be a thriving trade in the sale of what for want of a better phrase was known to we adolescents as "dirty pictures",always advertised in various dubious magazines as "the real thing". Of course they never were "the real thing" but when they arrived in the post there was always another address to send off to for what was really and truly "the real thing". And so on and so on.
BBD is the 21st century equivalent.
Asked for
empirical evidence (as opposed to computer models and hand-waving) that the 1.2C increase which ... will result from a doubling of CO2 will be further enhanced by positive feedbacks.all he does is refer to another posting of his which doesn't provide the requested information either for the very obvious reason that, no matter how much he wriggles and squirms, he is unable to provide the empirical evidence for this contention because no such evidence exists.
It may be that there is a positive feedback mechanism but I will believe it when I see evidence of it. BBD's posting which he refers to above does not provide anything beyond the usual unverified assumptions that followed the embarrassing discovery that CO2 is a lagging indicator of warming and therefore unable to be the cause thereof — in the absence of some very, very convincing proof.
Philip
You are a very generous minded person but I fear you are the only one who would ascribe "depth of knowledge" to BBD. He certainly talks the talk but as I indicated above when asked to provide a simple answer to a simple question he either diverts the question (usually as in this case to one of his own replies which doesn't answer the question) or fires off a blizzard of technobabble designed to make him seem more knowledgeable than he really is.
As shub and geronimo have both pointed out in their separate ways, BBD is a fully signed-up AGW-believer based on precious little evidence except the increasingly suspect meanderings of Hansen and a few others.
Mike Jackson
Mike,
Both Gixxerboy and RB have also expressed respect for BBD's literature knowledge. It is no mean feat - WG1 references about 6000 distinct papers. I agree that BBD has a blind spot when it comes to internal variability, but he is not alone in that. As far as I have checked, the 6000 does not include any of the modern papers on the subject!
I also don't think BBD is in any sense a green fanatic. He has already expressed doubt on this thread that wind turbines will provide the UK's energy needs. In the past (if I recall correctly), he has expressed sympathy with the policy ideas in the Hartwell paper (I don't know if this is still the case?). I don't know how he feels about the UK CCA, but I'd be interested to find out.
Shub,
Can I ask you to be a little more specific in your question, please?
Philip Richens
Philip
The one point on which BBD and I are indeed at one is in the futility of wind-operated power stations and to that extent I believe he is not beyond redemption!
I agree he has also done a power of reading — but all of it from papers by committed warmists and I seriously doubt that he understands more than a fraction of what he has read. And that is not a criticism of him either; I suspect the same could be said of a number of climate scientists.
It's the absolute certainty on every aspect of the subject that worries me and the out-of-hand dismissal of those who don't toe his new-found party line.
(Also his reluctance to answer a straight question!)
Mike Jackson
I was out on sunday night looking for perseids. Only saw four, but I started wondering about those little pinpoints of light up there. How do I know they are really gigantic fusion systems millions and millions of millions of miles away? And yet I am pretty sure. BBD has certianty issues. He picks the things to be certain of on grounds which I cannot understand. There's a tendency on the part of some sceptic to seize on any new theory which comes up on WUWT as an alternative to CAGW and believe it because that's what they want to believe. I don't think such behaviour is appropriate. Everything must stand the test of examination and falsifiability. Proof maybe not, but absence of disproof. Nothing can be taken as a given. And even if you like a theory, if it fits in with your worldview, that doesn't make it true. It should make you work harder to disprove it. Most folks on both sides don't do that. BBD is one of them.
rhoda
Philip
The fact is simply that for the kind of complex system that is the climate, everything I know (true, not a lot!) tells me to consider simple toy models; to use simple physical arguments; to keep on referring back to the data; to not be a slave to the data. I think you are mistaken to consider stochastic variation as an alternative to other perspectives. They are complementary, in my opinion.
Perhaps I haven't been clear enough. Of course stochastic variability is an aspect of climate behaviour (per Huybers & Curry). But in the context of the 'debate' over modern warming this is verging on misdirection.
Once again, in the space of a single exchange, the RF from CO2 has simply *vanished* from the table. The subtext here is modern warming. Modern warming is and will continue to be driven by the increasing RF from the increasing atmospheric fraction of CO2. Stochastic variability is almost an irrelevance to discussions of the climatological effects of CO2 forcing.
Again, this whole thing feels like an exercise in 'look, a squirrel'. But what about the elephant?
BBD
rhoda
It should make you work harder to disprove it. Most folks on both sides don't do that. BBD is one of them.
This is an assertion for which you have no evidence. But we can infer. Ask yourself this: how and why did BBD move from being a lukewarmer to acceptance of the consensus on climate sensitivity? Does this not *require* that I spent much time and considerable effort doing exactly what you claim I do not?
Now I know you only come out with this rhetorical crap to score blog points, but it's cheap, it's irritating, and above all, it does you more damage than me. So perhaps you could restrain the urge in future, for both our sakes?
BBD
Stochastic variability is almost an irrelevance to discussions of the climatological effects of CO2 forcing.
Attribution of recent warming remains a matter of controversy. The reason for this lies in the difficulties in disentangling anthropogenic effects from those due to natural variability. Therefore, any advance in the understanding of natural variability is likely to also advance attribution studies. Any advance in attribution studies will clarify the climatological effects of CO2 forcing. Stochastic variability is a significant tool in understanding natural variability. Therefore your statement is (almost) self-contradictory.
Don’t worry though, because I don’t have the answers either. I rather think this thread has run out of steam now, so unless you’ve anything interesting to add or any questions, I’ll catch up with you later.
Philip Richens
"Does this not *require* that I spent much time and considerable effort doing exactly what you claim I do not?"
Nope. Why would it? I have no idea of your decision process, only that it gives value to things I find unconvincing, and vice versa. And of course the actual amount of time and effort involved in coming to any conclusion is not in itself an indication of correctness. The issue here is not even whether you ARE right, but the degree of certainty. Your sneering attitude doesn't help, of course.
rhoda
Philip
Attribution of recent warming remains a matter of controversy.
I think we will have to agree to differ about this. I'll stick with the mainstream scientific position that attribution for warming post-1950 is substantially anthropogenic. I have seen *no evidence* that it could possibly be anything else - including natural variation.
And all the RF from all that CO2 is going to have a climatological effect. Much as if an elephant stood on your foot it would have an effect.
Thanks for the discussion though. It's always nice to deal with knowledgeable, civil people.
BBD
rhoda
Your sneering attitude doesn't help, of course.
Nor does your editorialising at my expense. I've already asked you to stop it, but you seem incapable of self-restraint, which is a shame.
And you aren't thinking, which is worse. How would I move from lukewarmer to consensus without close examination and rejection of the (admittedly sparse) scientific argument for low CS? But at the time I *believed* in a low CS. So I did exactly what you claim I did not. Obviously. Reasoning by inference seems to be a weak spot with sceptics.
BBD
Philip
But:
2/ Persistent changes in albedo require an energetic explanation precluded by (1) unless the forcing is sustained
In a system dominated over longer time scales by conservation of energy, how do you account for this persistent albedo change? Unless by a change in forcing? Remember, cloud albedo is a feedback. This is what I mean by perpetual motion machine thinking.
Busy now - more later.