Today will actually be fun, because it involves criticism of some of my writing around what I find to be the most interesting issue in climate, that of feedback effects. I have said for a while that greenhouse gas theory is nearly irrelevant to the climate debate, because most scientists believe that the climate sensitivity to CO2 acting along without feedbacks is low enough (1.2C per doubling) to not really be catastrophic. So the question whether man-made warming will be catastrophic depends on the assumption of strong net positive feedbacks in the climate system. B Kalafut believes I have the wrong mental model for thinking about feedback in climate, and I want to review his post in depth.
Naming positive feedbacks is easy. In paleoclimate, consider the effect of albedo changes at the beginning of an ice age or the “lagging CO2” at the end. In the modern climate, consider water vapor as a greenhouse gas, or albedo changes as ice melts. In everyday experience, consider convection’s role in sustaining a fire. Consider the nucleation of raindrops or snowflakes or bubbles in a pot of boiling water. At the cellular level, consider the voltage-gated behavior of the sodium channels in a nerve axon or the “negative damping” of hair cells in the cochlea.
I am assuming he is refuting my statement that “it is hard to find systems dominated by strong net positive feedbacks that are stable over long periods of time.” I certainly never said individual positive feedbacks don’t exist, and even mentioned some related to climate, such as ice albedo and increases in water vapor in air. I am not sure we are getting anywhere here, but his next paragraph is more interesting.
On to the meat of Meyer’s argument: he seizes on one word (“feedback”) and runs madly, from metaphor to mental model. Metaphor: “like in an ideal amplifier”. Model: The climate experiences linear feedback as in an amplifier–see the math in his linked post or in the Lindzen slides from which he gets the idea. And then he makes the even worse leap, to claiming that climate models (GCMs) “use” something called “feedback fractions”. They do not–they take no such parameters as inputs but rather attempt to simulate the effects of the various feedback phenomena directly. This error alone renders Meyer’s take worthless–it’s as though he enquires about what sort of oats and hay one feeds a Ford Mustang. Feedback in climate are also nonlinear and time-dependent–consider why the water vapor feedback doesn’t continue until the oceans evaporate–so the ideal amplifier model cannot even be “forced” to apply.
First, I don’t remember ever claiming that climate models used a straight feedback-amplification method. And I am absolutely positive I never said GCM’s use feedback fractions. I would not expect them to. This is a total straw man. I am using a simple feedback amplification model as an abstraction to represent the net results of the models in a way layman might understand, and backing into an implied fraction f from published warming forecasts and comparing them to the 1.2C non-feedback number. Much in the same way that scientists use the concept of climate sensitivity to shortcut a lot of messy detail and non-linearity. I am, however, open to the possibility that mine is a poor mental model, so lets think about it.
Let’s start with an analogy. There are very complicated electronic circuits in my stereo amplifier. Nowadays, when people design those circuits, they have sophisticated modeling programs that can do a time-based simulation of voltage and current at every point in the circuit. For a simulated input, the program will predict the output, and show it over time, even if it is messy and non-linear. These models are in some ways like climate models, except that we understand electronic components better so our parametrization is more precise and reliable. All that being said, it does not change the fact that a simple feedback-gain model for sections of the complex amplifier circuitry is still a useful mental model for the process at some level of abstraction, as long as one understands the shortcomings that come from any such simplification.
The author is essentially challenging the use of Gain = 1/ (1-f) to represent the operation of the feedbacks here. So let’s think about if this is appropriate. Let’s begin with thinking about a single feedback, ice albedo. The theory is that there is some amount of warming from CO2, call it dT. This dT will cause more ice to melt than otherwise would have (or less ice to form in the winter). The ice normally reflects more heat and sunlight back into space than open ocean or bare ground, so when it is reduced, the Earth gets a small incremental heat flux that will result in an increase in temperatures. We will call this extra increase in temperature f*dT where f is most likely a positive number less than one. So now our total increase, call it dT’ is dT+f*dT. But this increase of f*dT will in turn cause some more ice to melt. By the same logic as above, this increase will be f*f*dT. And so on in an infinite series. The solution to this series for a constant value of f is dT’ = dT/(1-f) … thus the formula above.
So the underlying operation of the feedback is the same: Input –> output –> output modifies input. There are not somehow different flavors or types of feedback that operate in radically different ways but have the same name (as in his Mustang joke).
The author claims the climate models are building up the affects of the processes like ice albedo from its pieces, ie rather than abstracting in to the gain formula, the models are adding up all the individual pieces, on a grid, over time. I am sure that is true. The question is not whether they use the simplified feedback formula, but whether it is a useful abstraction. I see nothing from my description of the ice albedo process to say it is not.
What happens if there are time delays? Well, as long as f is less than 1, the system will reach steady state at some point and this formula should apply. What happens if the feedback is non-liner? Well, in most natural systems, it is almost certainly non-linear. In our ice albedo example, f is almost certainly different at different temperatures levels (for example, a change from -30C to -31C has a lot less effect on ice albedo than a change from 0C to 1C. The factor f is probably also dependent on the amount of ice remaining, since in the limit when all the ice is melted there should be no further effect. But I would argue that when we pull back and look at the forest instead of the trees, a critical skill for modelers who too often get buried in their minutia while losing the ability to reality-check their results, that the 1/(1-f) is still an interesting if imperfect abstraction for the results, particularly since we are looking at tenths of a degree, and its hard for me to believe that it is wildly non-linear over that kind of range. (By the way, it is not at all unusual for mainstream alarmist scientists to use this same feedback formula as a useful though imperfect abstraction, for example in Gerard H. Roe and Marcia B. Baker, “Why Is Climate Sensitivity So Unpredictable?”, Science 318 (2007): 629–632 Not free but summarized here.)
To determine if it is a useful abstraction, I would ask the author what conclusions I draw that fall apart. I really only made two points with the use of feedback anyway.
- I used the discussion to educate people that feedback is the main source of catastrophic warming, so that it should be the main focus of the scientific replication. We can argue all day about time delays and non-linearity, but if the IPCC says the warming from CO2 alone is going to be 1.2C per doubling and the warming with all feedbacks considered is going to be, say, 4.8C per doubling (the author says himself that the models all converge at constant CO2), then we can say feedback is amplifying the initial man-made input by 4, or alternatively, 75% of the warming is from feedback effects, so these are probably where we need to focus. I struggle to see how one can argue with this.
- I used the simple gain formula to say if feedback were quadrupling temperatures, this implies a feedback factor of 0.75, and that this number is pretty dang high for a long-term stable system. Yes, the feedback is non-linear, but I don’t think this is an unreasonable reality check on the models to see what sorts of average feedbacks are being produced by the parameters.
The author’s points on non-linearity and time delays are actually more relevant to the discussion in other presentations when I talked about whether the climate models that show high future sensitivities to CO2 are consistent with past history, particularly if warming in the surface temperature record is exaggerated by urban biases. But even forgetting about these, it is really hard to reconcile sensitivities of, say, four degrees per doubling with history, where we have had about 0.6C (assuming irrationally that its all man-made) of warming in about 42% of a doubling (the effect, I will add, is non-linear, so one should see more warming in the first half than the second half of a doubling). Let’s leave out aerosols for today (those are the great modeler’s miracle cure that allows every model, even those of widely varying CO2 sensitivities and feedback effects, all exactly back-cast to history). These time delays and non-linearities could help reconcile the two, though my understanding is that the time delay is thought to be on the order of 12 years, which would not reconcile things at all. I suppose one could assume non-linearity such that the feedback effects accelerate with time past some tipping point, but I will say I have yet to see any convincing physical study that points to this effect.
Well, the weather is lovely outside so I suppose I should get on with it:
Meyer draws heavily from a set of slides from a talk by Richard Lindzen before a noncritical audience. These slides are full of invective and conspiracy talk, and their scientific content is lousy. Specifically, Lindzen supposedly estimates effective linear feedbacks for various GCMs and finds some greater than one. The mathematics presented by Lindzen in his slides does not allow that, and he doesn’t provide details of how such things even could be inferred. An effective linear feedback greater than one implies a runaway process, yet GCMs are always run for finite time, so there cannot be divergence to infinity. Moreover, as far as I know, all of the GCMs are known to converge once CO2 is stabilized.
I draw on Lindzen and Lindzen is wrong about a bunch of stuff and Lindzen uses invective and conspiracy talk so, what? Lindzen can answer all of this stuff. I used one chart from Lindzen, and it wasn’t even about feedback (I will reproduce it below).
I did mention that in theory, if the feedback factor is greater than one, in other words, if the first order feedback addition to input is greater than the original input, then the function rapidly runs away to infinity. Which it does. I don’t know what Lindzen has to say about this or what the author is referring to. My only point is that when folks like Al Gore talk about runaway warming and Earth becoming Venus, they are really implying runaway positive feedback effects with feedback factors greater than one. Since I really don’t go anywhere with this and in reality the author is debating Lindzen over an argument or analysis I am not even familiar with, I will leave this alone. The only thing I will say is that his last sentence seems on point, but his second to last is double talk. All he is saying is that by only solving a finite number of terms in a a divergent infinite series his calculations don’t go to infinity. Duh.
I am open to considering whether I have the correct mental model. But I reject the notion that it is wrong to try to simplify and abstract the operation of climate models. I have not modeled the climate, but I have modeled complex financial, economic, and mechanical systems. And here is what I can tell you from that experience — the more people tell me that they have modeled a system in the most minute parametrization, and that the models in turn are not therefore amenable to any abstraction, the less I trust their models. These parameters are guesses, because there just isn’t enough understanding of the complex and chaotic climate system to parse out their different values, or to even be clear about cause and effect in certain processes (like cloud formation).
I worry about the hubris of climate modelers, telling me that I am wrong and impossible to try to tease out one value for net feedback for the entire climate, and instead I should be thinking in terms of teasing out hundreds or thousands of parameters related to feedback. This is what I call knowledge laundering:
These models, whether forecasting tools or global temperature models like Hansen’s, take poorly understood descriptors of a complex system in the front end and wash them through a computer model to create apparent certainty and precision. In the financial world, people who fool themselves with their models are called bankrupt (or bailed out, I guess). In the climate world, they are Oscar and Nobel Prize winners.
This has incorrectly been interpreted as my saying these folks are wrong for trying to model the systems. Far from it — I have spend a lot of my life trying to model less complex systems. I just want to see some humility.
Postscript: Here is the only chart that I know of in my presentation from Lindzen, and its not even in the video he links to, it is in this longer and more comprehensive video
That seems a reasonable enough challenge to me, particularly given the data in this post and this quote from Judith Currey, certainly not a skeptic:
They don’t disprove anthropogenic global warming, but we can’t airbrush them away. We need to incorporate them into the overall story. We had two bumps—in the ’90s and also in the ’30s and ’40s—that may have had the same cause. So we may have exaggerated the trend in the later half of the 20th century by not adequately interpreting these bumps from the ocean oscillations. I don’t have all the answers. I’m just saying that’s what it looks like.
Again, as I have said before, man’s CO2 is almost certainly contributing to a warming trend. But when we really look at history objectively and tease out measurement problems and cyclical phenomena, we are going to find that this trend is entirely consistent with a zero to negative feedback assumption for the climate as a whole, meaning that man’s CO2 is driving 1.2C or less of warming per doubling of CO2 concentrations.
Great post.
I too have dedicated a lot of time creating mathematical models, only I do so for gene interaction networks, some are positive feedbacks, some negative, some both, and I’ve attempted to deal with time delays (which isn’t fun). And maybe the single most important thing you have to understand about models is that they are only as good as what you put in. And you can only put in what you know, or you hypothesize is true.
In biology, I’m faced with creating models when I might really know 10-20% of the parameters in my system (if I’m lucky, sometimes its just 1 or 2 out of 50 or so). Doing experiments to determine these parameters are costly, time consuming and difficult. But at least I can run experiments to try and figure out a few key parameters. What experiments can climatologists run?
Also, when it comes to modeling, I can create a hypothesis, run a controlled series of experiments changing various conditions to test it, and fit my data to my model (thus attempting to get good guesses at all the parameters without trying to directly measure them). Climatologists can’t do this. Engineers, chemists and physicists can too, while economists can’t. I believe this is what really separates the sciences. In some fields you can experiment while other’s you can’t, and the ones you can experiment in are always going to be “better.” Meaning that those fields will always have a much higher level of certainty in their results.
So when I see these claims of “the science is settled” and AGWers pretending they “know” the effect of CO2 on X, Y and Z. I can’t help but think about what we’d say if economists came out and said they were settled, and they “know” the effects changing the prime rate to 2% (or something), and all the effects that would have, from unemployment, to GDP growth, to foreclosure rates, to the price of gold, and the Dow Jones average. For the most part economists know the limits of their models, and pretty much anything they do is just a good guess, and only true given some set of assumptions that may or may not hold in the real world. They know they can’t determine the exact effect of A on to B, particularly when C-M probably also effect B. This is why when you read an economic paper they often have a large discussion about when they think their model might be right or wrong, other ways they could have changed the model, etc.
Why don’t I get the feeling climatologists understand these things too? They can’t determine the effect of CO2 on ice albedo, because they can’t run a controlled experiment that would eliminate other factors they don’t understand (say clouds) from also effecting ice albedo. And even if they did know that, they wouldn’t know CO2’s effect on cloud formation, then cloud formation’s effect on ice albedo. So, even if CO2 does have positive feed back on ice albedo directly, CO2’s might have a negative effect on ice albedo through cloud formation that out weighs the direct feedback.
Also, since when is a voltage gated ion channel long term stable? It includes positive feedback for sure, but ultimately the negative feedback takes over. And this is the norm of biological systems. There maybe short periods of positive feedback to initiate a cascade of events, but eventually that sequence of events has to end, and its terminated through negative feedback. In general positive feedback is just not stable, and I have a hard time believing our Earth’s climate is teetering on a just a locally stable saddle point given what we know about the Earth’s history.
Interesting comment Wally.
I have a question wrt ‘gene interaction networks’ (and how this may be compared to climate/weather interactions).
Are dominant genes (systems/networks) always dominant, or is it just that our understanding of non-dominant genes (systems/networks) is still far too incomplete.
How much does methylation affect what we think we know?
Tony, those are fairly involved questions.
Firstly, genes aren’t dominate or recessive. Different alleles for a particular gene are dominate. So when we say an allele is ‘dominant’ all we really mean is that we would observe the phenotype created by that allele over that of a different allele for the same gene. So assigning this dominate or recessive tag has everything to do with what phenotypic characteristics you’re talking about. And because gene’s often have influence of multiple different characteristics, its entirely possible that one allele could be dominate in one case, co-dominate in another, and recessive in the next. So, when we attempt to put this into a system or genetic network, we need to understand the role of both alleles. So I could model a system where you might be homozygous for a recessive mutation, and in another case I could model it like you’re heterzygous for this mutation. So, yes this certainly could have an effect. Particularly if its the type of interaction where you need both functional copies to be “normal,” such as say the sickle-cell trait.
Now, methylation falls under the catagory of gene regulation. There are two basic kinds of methylation as well. DNA methylation is used for gene silencing during development. So as your cells differentiate, different genes will be turned off semi-perminately. Now there is also histone methylation (DNA is wrapped around histones for packaging and needs to be unwrapped to become “active”). So, if we wanted to, we could easily model histone methylation by histone methyltransferaces to turn off genes, and demethylation to turn them back on. But, its not always that simple. Some methylation activates others inactivate. Both of these areas are not perfectly understood. As in some cases DNA methylation can be reversed as well.
These are all the kinds of finer points we have to consider when making models. Its not just as simple as A turns B off, we need to model how it does it. Does it do it by histone methylation, or does it bind to the protein that gene creates and promote degredation, etc.
For what it’s worth, your amplifier uses negative feedback to eliminate distortion. AGW discussions perhaps merit the same treatment!
Interested in Wally’s comments. Have heard the like from a close relative in the banking world.
There is another discipline, very well funded and with the very best in CIT, which makes mathematical models all the time and COMPARES THE RESULTS WITHE THE ACTUAL OUTCOME REGULARLY. Strangely enough, it works on very much the same data as climate modelers use. It is known as meteorology, and it STILL can’t tell me what the weather will be like next Sunday.
What is climate but weather over a time period? Is climate chaotic too? Is the whole world in a state of …. never mind.
I originally picked up my skeptical outlook on Catastrophic AGW from John Daly’s website.
http://www.john-daly.com/miniwarm.htm
According to astronomical theory, the sun was only about 70% as luminous as it is now 4.5 billion years ago, and has been warming ever since. Despite that, there have been liquid oceans, and life on earth for at least 3.8 billion years. Hsien Wang-Ou thinks this is due to strong negative feedbacks due to clouds.
http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1520-0442(2001)014%3C2976%3APBOTES%3E2.0.CO%3B2
Plugging in Boltzmann’s equation, the higher the temperature, the less effect any further wattage increases have on increasing temperature. Right now, in round figures, we get about 240 watts from the sun. The sensible flux at earth’s surface is about 390 watts thanks to the greenhouse effect. The effective temperature increase is about 33C.
33C(greenhouse temperature increase)/150 watts(greenhouse wattage increase)
= 0.22 C/watt. According to AGW theory, the increase in wattage due to a doubling of CO2 would be about 3.8 watts.
3.8 watts * 0.22 C = 0.836 C. Since the 0.22 C is the AVERAGE over 240 to 390 watts, and the sensitivity decreases with temperature increase, it stands to reason that the current sensitivity should be somewhat less than 0.22 C. As someone pointed out on Watts’ blog,
http://wattsupwiththat.com/2010/03/16/another-look-at-climate-sensitivity/
there would be feedbacks due to the CO2 increase, so we cannot say the increase will be just 3.7 watts. Say thanks to feedbacks due to water vapor and albedo changes due to melting glaciers, the effect is a doubling to 7.43 watts- in that case, using earth figures, the warming would still be only about 7.4* 0.22 = 1.628 C at most- and that’s without taking int consideration negative feedbacks from clouds and the latent heat evaporation.
“I am open to considering whether I have the correct mental model”
Ha ha ha. When 95% of your posts are nothing but regurgitation of previous posts, and when you never respond to comments or give any hint that you even read them, let alone understand them, it’s hard to see how you can consider yourself ‘open to considering’ anything. All impressions are that you’re a moron in a hurry and you’ll never get to grips with even very basic science, but it’s clearly not going to stop you weirdly believing that you can.
You certainly haven’t considered anything in this post. You have just regurgitated previous bullshit. Let’s express this in as few words as possible: your formula is utterly irrelevant and meaningless in the context of climate. It would become less meaningless if expressed as ΔT’ = ΔT/(1-f(t, T, φ, λ)) at the very least.
I confidently predict that you will fail to understand any comments made here, you will fail to modify your wrong thinking even a fraction, and you’ll post the same rehashed nonsense again and again ad infinitum.
LOL at hunter’s last comment. I love the irony of the crap he just spewed.
“LOL at hunter’s last comment. I love the irony of the crap he just spewed.”
How so, Retnuh? What this rather, uh, outspoken version of the hunter character seems to have is a science background. If his/her equation is wrong above, point it out. Explain it to us.
It is interesting what happens when people with strong science backgrounds come into contact with CS.
I have wondered why water vapor by itself does not cause autocatalytic warming. A slight rise in temperature causes H2O partial pressure to increase, causing more warming. This increases water PP even more, causing even more warming. Since vapor pressure of water increases exponentially with temperature, this process should accelerate.
Why do we need CO2 to start this process? An increase in temperature from ANY cause should set this process in motion. The fact that this does not happen suggests that there is some other mechanism that offsets this effect. Svensmark and others attribute this to cloud formation, which also goes up exponentially and overcomes the greenhouse effect of the water vapor.
It is a huge mistake to become so enamored of one’s own hypothesis that one loses objectivity.
This seems to be occurring on a massive scale in the climate research community.
Thanks Wally
Waldo,
I have no problem with you. In fact, among all the people who post regularly on this blog, I probably find myself agreeing with your arguments moreso than anyone else. I would not describe myself as a “climate skeptic” in the same way that the people on this blog do. I am only skeptical in the sense that I’m skeptical by nature about everything. My first inclination is to accept the findings of the majority of researchers and scientists in the field. I certainly don’t believe that anthropogenic climate change is a hoax, fraudulent, or a conspiracy. I defer to the to experts because I have neither the resources nor the expertise to make a cogent argument against it.
My problem is with hunter. At the very best he is a troll. He adds absolutely nothing to arguments against the points made by people on this blog. If you don’t find any irony to him saying “95% of your posts are regurgitation” or “it’s hard to see how you can consider yourself ‘open to considering’ anything”, fine. If you want to defend him, be my guest. However, I’m tired of his antics. At this point I half-suspect he is a climate change denier who is attempting to masquerade as a troll in order to antagonize people against climate scientists.
Warren,
First, I agree pretty much with your entire post. But I think it is important to stress that “whether the Coyote Blog Feedback Model is correct” is not the question.
The question is whether the existing computer models showing AGW are correct. What are their feedback models and why are they correct?
If Kalafut wants to rely on a model, s/he has the burden of proof to show that it is correct.
The answer to the question in this post’s title is yes.
“The answer to the question in this post’s title is yes.”
But “no” when that question is applied to any other discipline. There is no discipline so incredibly “insulated” from standard inquiry as CS.
Ted,
Good observation. Its somewhat similar to the AGW theory seemingly ignoring the fact that we’ve had much higher CO2 levels in the past.
“It is a huge mistake to become so enamored of one’s own hypothesis that one loses objectivity.”
But they have to prove their hypothesis, otherwise their funding runs out. If the climate science where “settled” and humans could not significantly alter the Earth’s climate, how much money would such a field draw?
Then of course the politicians love it because it gives them something to “save the people” from.
Now that’s a positive feedback loop.
What could be more appropriate than for Waldo, and hunter(the phony twit), to be soul mates?
****”I have no problem with you.”
Wonderful! That is very nice to hear. And it is nice to find a fellow agnostic in the threads amongst all this neocon certainty. And it is even nicer for someone besides myself to admit that they too understand their limitations. I myself have no problems with anybody, although I will admit that I do not respond often to hunter #2 because of his/her very virulent style of posting. I will say, however, that no matter how cutting hunter #2 may be, his/her last comment was rather on-point.
****”What could be more appropriate than for Waldo, and hunter(the phony twit), to be soul mates?”
But hunter #1, I thought you and I were sole mates?! Have I offended you in some way? You know that I greatly respect your repeated demonstrations of critical thinking skills, your poodle-like devotion to Mr. Meyer’s clearly reasoned blog-postings, your interesting use of the comma, and your thorough knowledge of blog-science! Say you’ll be mine again, dearest heart!
Waldo,
I would not dream of interfering with your obviously deep true-to-heart affinity.
And you are clearly the one licking and sniffing, dog like, at any AGW promoter strutting by, so I will leave you to it.
Alas, like a typical stray, you thought that once you were fed a bit, you were owned.
If only there was an animal control service for trolls…..
im the real one 🙂
I’m hunter and so’s my wife.
Well, if the climate scientists would just release their data and computer models to the public, we wouldn’t have to spend so much time arguing about what is or is not inside them… it sure would save everyone (warmers and skeptics alike) a lot of time.
Frankly, I’m less concerned with the models than I am with how temperatures are measured and “adjusted/homogenized”. Until we get a handle on how much of the recent warming is spurious, all of this discussion may well be moot.
I’m hunter, and so is my wife and dog.
“Until we get a handle on how much of the recent warming is spurious”
…or how much we are under-estimating the current warming trend. Is there some reason you think the trend can only be over-estimated and not under-estimated?
Cunter, probably because the adjustments have taken the numbers up and not down?
And is there some reason you think they should not have taken them up further?
Because they adjust city temps that suffer from the UHI effect upwards.
No they don’t.
yes, they do.
Isn’t this fun.
Nice to see you have run out of anything resembling a cognitive thought.
You’ve just blown us all away with the intellectual rigour and critical thinking evident in that last comment.
First, I now realize I put “cunter” as the poster in my post of “Because they adjust city temps that suffer from the UHI effect upwards.”
I guess, I’m not used to all this writing your name in for each post.
Second, its interesting you attack someone for not displaying “intellectual rigour and critical thinking” after that little sequence of “No they don’t.” “Yes, they do.”
I didn’t realize I was talking to my 4 year old.
I argued this point on realclimate.org
My comments are #247, and 303 and others in realclimate:
# 247 netdr says:
14 March 2010 at 8:06 PM
I am a skeptic that believes in looking at evidence from both sides of the argument.
The argument for AGW that I have never been able to believe is that the earth’s climate can amplify the warming of CO2 by overall positive feedback !
The open loop [no feedback] warming of CO2 is 1.2 degree C for a doubling.[Per Dr Hansen]
As I understand the science the climate alarmists believe that the earth’s climate is an overall positive feedback system. This positive feedback amplifies CO2’s puny warming by a factor of 6 or more.
Since the earth’s temperature has only varied by 2/10 of 1 % in 100 years. This is very very very stable. How can a positive feedback system be this stable.
I am an engineer and understand control theory and design systems with positive and negative feedback, I have never run into a long term stable positive feedback system.
Can someone please name another long term stable positive feedback system ?
Is the earth’s climate the only one ?
Do you believe it is?”
*************************************
The replies I received were interesting.
One responder invoked the “Alice in wonderland defense” saying overall positive feedback didn’t mean the same thing as it does in engineering. [A word means exactly what I want it to mean nothing more nothing less.]
He claimed that it means “amplification” in climate speak.
He claimed that all climate scientists know that the total equation is overall negative due to the fact that the energy radiated away into space increases as the 4 th power of temperature resulting in a huge negative feedback overall.
A few got abusive but I got some interesting comments too. You can see the discussion at realclimate.org
The story is “why we bother” !
http://www.realclimate.org/index.php/archives/2010/03/why-we-bother/comment-page-5/#comments
I don’t know the real answers. Any thoughts?
netdr,
If Hansen’s predictions about Earth becoming Venus due to CO2 were true, we would not be here now.
Your characterization of AGW believers invoking an Alice in Wonderland defense is a great way to describe the process they depend on to sustain their strange ideas.
You are one of the fortunate few who got past the RC imams and posted even a tough question. Congratulations.
The Saturated Greenhouse Effect elegantly finesses the positive/negative feedback question. “Dr. Miskolczi’s Constant was discovered with a program that is the result of a project started 25 years ago in Hungary. It was then he began the process of writing a high-resolution radiative transfer program which would describe the Earth’s climate using the TIGR Global radiosonde archive of the Laboratoire de Meteorologie Dynamique, Paris database. With this information he was able to accurately describe mathematically how the atmosphere absorbs and releases heat using a long standing Equation called the Schwarzschild-Milne transfer equation to accurately calculate the Earths infrared optical depth. That is what Global climate is; the process by which Earth either holds onto or releases heat. The IPCC and the CRU scientists would have us believe that CO2 increases the heat the atmosphere holds on an infinite unlimited basis. That conclusion is absolutely false, and the CRU and the IPCC have had to falsify and invent data to make it appear that it does.
In reality water is so overwhelming abundant on Earth, it dominatingly, completely, and overwhelmingly governs the climate equilibrium of the Earth. It is 71% of the total surface area of the planet, 333 Million cubic miles … of water exist here, by far outweighing all other greenhouse gasses.
Can our climate undergo changes due to the addition of greenhouse gasses? Yes, but only under circumstances great enough to overwhelm the presence of 333 million Cubic miles of water, such as the impact of a large Asteroid and the tremendous heat it would add instantly. Carbon Dioxide is very far inside the greenhouse effect’s self-regulatory barriers. Amounts even double our current emissions, cannot overwhelm this equilibrium. Only the Sun has that immense amount of power, and only water exists in quantities large enough to effect such a change. As long as the sun’s activity is the “business-as-usual” fluctuations and there is water on Earth, CO2 cannot cause or increase global warming.”
Past very high levels of CO2 did not cause run-away warming. Past periods of greater warming – the Medieval Warm Period, Roman Warm Period, Holocene Climate Optimum, did not trigger run-away warming by releasing vast quantities of methane from permafrost, etc. – even though CO2 increased following the warming (and cooling began before CO2 decreased).
The saturated greenhouse effect explains why.
Increasing atmospheric CO2 doesn’t even explain changes in climate during the past century, such as the warming 1920-1940 which looks just like 1980-2000, or the cooling 1940-1975 or 2000 to present.
*****“if the climate scientists would just release their data and computer models to the public, we wouldn’t have to spend so much time arguing about what is or is not inside them… it sure would save everyone (warmers and skeptics alike) a lot of time.”
I find this comment, and the perennial comments like it, somewhat perplexing given that there is so much IPCC information – including computer code posted on Real Climate – available to the public for free. Literally thousands of pages of information are only a click or two away. The same can be said of Hansen’s work, the NOAA/NCDC, and any number of other resources (if people were really, truly interested in getting hold of, say, journal articles and the like they are fairly accessible through public libraries and / or academic libraries – most librarians are friendly people and would probably be willing to help anyone here find whatever they wanted). In fact, I cannot readily think of any movement which is so readily open to the world – institutions which actively invite investigation, actually. And yet there seems to be an inverse reaction to this level of transparency as witnessed above.
I cannot parse this kind of thought except that it is borne out of ignorance of these readily available resources. But I doubt that this is really why people post this kind of demonstrably egregious statement.
I think that the very openness of the AGW camp is a fantastically compelling argument in their favor (I do note that a good many of Mr. Meyer’s posts are pure unsullied, uncited, unapologetic conjecture or graphics from other blogs or who-knows-where). And I imagine this is why so many people want to disbelieve, and in fact assert the opposite of, the obvious.
Any critically thought-out comments?
I too find the “adjustments” made to the temperature readings to be troubling. They should be mostly negative to correct for UHI effect. Small towns get larger [generally] and large ones get larger. Even effects like automobiles spewing water vapor [even hydrogen cars] and people watering their lawns all cause spurious heating which must be removed to get true temperature variation.
Here are NOAA’s temperature adjustments.
http://cdiac.ornl.gov/epubs/ndp/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif
Notice anything funny ?
As of 2009 they are adding .5 o C to increase the apparent warming.
Equipment changes etc should even out but UHI effects are almost all one way causing apparent spurious warming.
hink that the very openness of the AGW camp is a fantastically compelling argument in their favor.
“I don’t know what Lindzen has to say about this or what the author is referring to.”
The post to which my post was a response was linked from mine:
http://www.climate-skeptic.com/2009/06/its-all-about-the-feedback.html
Remember writing that?
From what source did you get the graphic? “Dr Richard Lindzen has this chart showing the feedback fractions f used in models, and the only surprise to me is how many use a number higher than 1 (such numbers imply runaway reactions similar to nuclear fission).” You link something on the Watts site. http://wattsupwiththat.com/2009/06/02/lindzens-climate-sensitivty-talk-iccc-june-2-2009/
(1) Note that you wrote “Feedback fractions used in models”. Perhaps your own understanding has improved greatly between June of last year and now–now you claim that feedback fractions are merely a nice way to give a lay audience a single number, like climate sensitivity–and a useful tool in analyses like that of Roe and Baker. I presume you know now that climate is not modeled as an amplifier.
(2) You were right to be surprised by how many feedbacks in Lindzen’s chart were greater than one. But put that “skeptic”ism to good use: It was immediately obvious that Lindzen could not have estimated feedbacks greater than 1 by the method given on his slides, and thus you should have concluded that Lindzen’s chart was, to use a technical term, horseshit.
I made it very clear in my post just what remarks of yours were under fire. This “I don’t know what Kalafut is talking about” stuff is a slimeball tactic.
It’s not my intent to get into an ongoing tangle–although, since he’s lecturing on climate yet again this Wednesday, a remark on something “fishy” in Meyer’s slides was queued up and might still be posted sometime on Tuesday–but this response was so “slippery”, so crafted to make me look like a loon and a liar, that I had to post something about it. See:
http://stochasticgain.blogspot.com/2010/03/meyers-underwhelming-response.html
“anon:
Warren,
First, I agree pretty much with your entire post. But I think it is important to stress that “whether the Coyote Blog Feedback Model is correct” is not the question.
The question is whether the existing computer models showing AGW are correct. What are their feedback models and why are they correct?
If Kalafut wants to rely on a model, s/he has the burden of proof to show that it is correct.”
“Anon”:
Read the papers. In no other field of inquiry has such a giant, publicly accessible review article been prepared. Download the WG1 report from the IPCC Fourth Assessment, then use Google Scholar to find the references.
You can bluster all you want about the “burden of proof” but it is not up to me to duplicate what’s in these papers singlehandedly. It’s up to you to read. Until you bother to read, take the timeless advice given in the classic film “The Mack”: “Shut the f*** up while grown folks is talking.”
Dr. Kalafut writes a fine blog. I thought this summed it up:
“I just caught Meyer claiming–despite my link to his original post, and despite the link to Lindzen in his, that he never claimed that climate models “use” feedbacks, that I’m making a straw man argument, and that he didn’t use an obviously bad analysis of feedback from a set of Lindzen slides as reference. It’s “I don’t know what Kalafut’s talking about, it’s a straw man argument!” in a way to make me seem like a liar and a loon. Again: Not cool. Mr Meyer: you’ve been caught. Perhaps your understanding of the science has matured in a year, but that doesn’t retroactively correct your past blunders nor does that retroactively turn criticism of your past statements into straw-man arguments.”
Again and again, when Mr. Meyer and the tribe run up against real scientists, they get handed their lunch.
****”If Hansen’s predictions about Earth becoming Venus due to CO2 were true, we would not be here now.”
Nope, nope, nope. hunter has typically gotten it wrong again. I had to spend a little time to make sure of what Hansen actually says, and his (expert) take is that in 100 years – let me say that again, a HUNDRED years – Earth’s climate could be as hot as it was 65 million years ago when the dinosaurs reigned. Nowhere does he claim that “we would not be here now” because Earth would be some sort of Venus-hell or anything of the sort hunter above implies.
This is another aspect of the deniosphere that I find fascinating – the deliberate misunderstanding of science. It is a kind of hyperbole meant to sound authoritative, as if gross exaggeration has the same merit as actual science.
Mr. Meyer was right about invalid arguments deconstructing themselves.
It seems to me that claiming that the models used feedback fractions or not seems like a strawman argument to me too.
If you simulate the process to the best of your ability and it inputs a value into the output which is linked to the input by whatever means you have a feedback. This feedback is positive or negative at any given iteration.
That is it aids or opposes the change in output. To me arguing about feedback fractions is just obfuscating the issue.
You could go over the models with a magnifying glass and argue each equation but in the final analysis the verification is done by whether the output matches reality.
Here are the predictions of 9 climate models starting in 1990
http://www.ig.utexas.edu/people/staff/charles/wpe6.gif?PHPSESSID=5bad55a0170f76d1bc284698bb3d4f35
Here is the temperature data to evaluate them against.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.txt [tainted though it might be]
As of 2008 :
One model predicted no warming and is clearly the winner!
Pretty poor performance in my opinion.
So far the results for predicting the past have been excellent, for predicting the future not so good.
Netdr,
“So far the results for predicting the past have been excellent, for predicting the future not so good.”
But that’s kinda the thing, predicting the past isn’t testing the model. Its creating the model. To test the model you need new data, either from an experiment, or just from time passing (which is not a very good option either, because it isn’t controlled).
Now you can attempt to use past data to both create and test the model by separating the data into two groups. People usually do this by taking odd day (or hour or week or month) measurements and putting them in one group to create/fit the model and even day measurements and putting them in the second group to test the model. But with the climate you are going to run into a few problems doing this. Probably by far the biggest problem, is that you will have forces that act mostly equally on both your odd and your even groups. Like say the Pacific Decadal Oscillation. That force will cause your odd and even measurement of any two time points to be highly correlated. So, you can’t break up your data into odd and even time points, unless you can space the data points out enough so that they are mostly independent of one another. Otherwise when you create the model with data set A, and then try to set the model with data set B which has a .99 correlation coefficient with data set A (remember this because data point A1 and B1, which is just A1+) have basically all the same forces acting on them), of course its going to fit nearly perfectly.
It seems to me, in order to attempt to create and test the model with past data for climate models, you’d need to have your data points separated by at least a couple years. But then that would require a lot more then 100 years or so worth of reliable data measurements, which we obviously don’t have. And even then we have forces acting on the climate of the earth that last much longer than even a century.
So of course, this is all just a long winded way of saying climate models suck. I’d say they are even worse then economic models, and I think we all know just how much we should trust economic models.
Climate models taktens of years at least to validate a prediction. Dr Hansen’s 1988 prediction looked pretty good until 2005 when the model predicted sharply rising temperatures, and nature provided us with falling temperatures. There was a simulated volcanic eruption which suppressed early warming or he would have been more wrong in 2005.
Here is a link to Dr Hansen’s 1988 predictions see page 7 Scenario “B”.
http://pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf
You will never get a true believer to analyze his track record in 2010. They all go back to his 2005 defense.
If it took 20 years to validate an electronic circuit model we would be simulating a basic capacitor correctly and possibly an inductor, but modeling would be in it’s infancy.
The models we have are the best we can do with our understanding of climate in 2010. There may be no attempt at deception just an honest disagreement about feedback.
No one doubts that both positive and negative feedback exists. Which one predominates is a debatable point.
It seems to me that for each iteration of the model all feedbacks sum to a value which opposes or amplifies any change in output. Hiding the calculation in a simulation is just an obfuscation.
“Dr Hansen’s 1988 prediction looked pretty good until 2005 when the model predicted sharply rising temperatures, and nature provided us with falling temperatures.”
Perhaps you are scientifically illiterate; perhaps you don’t live on the same planet the rest of us do. Perhaps you need to read Hansen 1988 again. Its intent was not to predict annual temperature anomalies. Its intent was to predict global temperature trends. Perhaps you could look up the average global temperatures for the 1980s, 1990s and 2000s. Tell us what they are. Tell us what Hansen 1988 actually predicted. Compare the two.
“There was a simulated volcanic eruption which suppressed early warming or he would have been more wrong in 2005.”
Do you know when the second-largest volcanic eruption of the 20th century happened? Do you know what effect it had on global temperatures? It seems from this statement that you do not.
*****”The models we have are the best we can do with our understanding of climate in 2010. There may be no attempt at deception just an honest disagreement about feedback.”
The smartest, most mature thing yet said on this blog. No demonizing. No hyperbole. No ill-spirit. Just an honest evaluation that takes into account the limitations of current science and the idea that human beings, even scientists, are fallible and that we can have civil, rational disagreements over unsolved scientific issues.
I’m a little puzzled by one thing, however…when I move the cursor over my moniker, Wally, hunter, anon., etc, there is no link; clearly we are just commentators on this site. When I move the cursor over Kalafut, James McC, and True Religion Clothing I am linked to either a blog or website. Clearly there is some sort of techno-cyber-magic going on here which links these commentators to their host sites. When I move the cursor over “netdr” and click I go back to the Climate Science home page. How come?
Waldo, do you have point with the website thing?
Do I have a point? No. Just a friendly question. An observation.
I do have some amateur questions about the sockpup…oops, I mean, netdr’s comments on the links (which do not appear to say what netdr claims they do – but I may not know what I’m looking at) but I am just wondering if it is worth my time to ask honest questions or am I talking to a…well, just wondering about the loop back to CS. That’s all.