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muoncounter at 06:08 AM on 27 October 2010Models are unreliable
#260:"Bridges fall, buildings collapse. Shuttles explode. ... They can get it wrong. " You're forgetting a significant cause of such unpleasant events: Google search 'operator error accidents'. Such is not the case in a climate model, where there is no one to push the wrong button, run past a red signal or close a valve that should be left open. -
Berényi Péter at 05:51 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#81 e at 02:54 AM on 27 October, 2010 My issue is that you implied a few times that the most likely scenario following a change in the climate landscape would be a return to an entropy maximum with a total rate of entropy production exactly equal to the previous local maximum. I don't see why you would get the impression that such a change would be the most likely scenario. In fact, given that the unknown future maximum could be either lower or higher to some degree, it is extremely unlikely that the new maximum will just happen to be identical to the previous maximum (or any specific value). No, I have not said such a thing. If you had the impression I had, it's probably my fault. What I am actually trying to say is this:- If IR optical depth of the atmosphere is increased by a small amount by adding to it some well mixed greenhouse gas while everything else is held constant, entropy production rate would decrease. I do not have a rigorous proof of this statement, but based on simplified model calculations I believe it's true.
- If that everything else is allowed to adjust now to the new situation, it would not change in a way that leads to further reduction of entropy production rate (MEP is used at this step).
- Therefore this spontaneous adjustment (a.k.a. feedback) does not amplify the effect of increased IR optical depth, but either leaves it unchanged or attenuates it, that is, the feedback is either neutral or negative.
- You may try to show that in some cases increased IR optical depth alone does not imply a decrease in entropy production rate.
- You could demonstrate the climate system has a unique structure that makes the MEP principle nonoperational in this case.
- Or show us while feedback on entropy production rate is indeed not positive, it can still be positive on surface temperatures.
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Heidi at 05:50 AM on 27 October 2010Medieval Warm Period was warmer
Thanks for the information, scaddenp. I understand your position, Doug. Unfortunately, there seems to be an unmet need for a lighter approach to climate science and global warming. Parts of this website fit the bill, others fall short. Mind you, I love listening in on your arguments and appreciate the intellectual rigor. However, I can tell you, most people have neither the education nor the time to understand climate science at this level and are, therefore, easy prey for the skeptics. Ultimately, of course, you will need to bring us along with you to achieve significant policy change... Is that the goal of this website? -
The 2nd law of thermodynamics and the greenhouse effect
e - Your objections to the introduction of the MEP hypothesis are extremely well written. I believe that's essentially what I attempted to say here, albeit not as clearly as you did. The MEP hypothesis, even if true, won't suddenly kick in to save us from global warming. If it's present, it's always been present, and can be considered part of the current feedbacks. Berényi still appears to be searching for the "mystery mechanism" that will induce negative feedback and cancel out AGW. -
Models are unreliable
mistermack, to add to fact that models have been successful in forecasting: Predicting the past is still a prediction (see retrodiction). If you build a simulation of a physical system, it is appropriate to test that simulation by comparing it to past performance of the real system. This is true of any physical model, including models of bridges and space shuttles. The fact that you are comparing to past data does not mean that the simulation has past data "programmed in" as you are implying. What you are thinking of is a statistical model, where the inputs are directly mapped to outputs via a mathematical relationship derived directly from historical data. This is not how physical climate models are derived. Since the model is built on physical laws and not on direct statistics, there is no reason to assume that a particular model could ever recreate past climate behavior, unless that model has some basis in reality. If the basic physics underlying the model are significantly off, then no amount of tweaking would ever result in an accurate recreation of past performance. The fact that it can recreate past performance is therefore evidence that the model is correct, since the likelihood is very slim that the model would be able to accurately recreate real performance if it was significantly wrong in its recreation of physics. -
archiesteel at 04:54 AM on 27 October 2010Models are unreliable
@mistermack: you have yet to demonstrate exactly how models are unreliable. You should provide evidence that supports your allegations, otherwise it's hard to take them seriously. -
Riccardo at 04:51 AM on 27 October 2010Models are unreliable
mistermack so we have a phenomenon, we build a theory (a model) and compare it to the observed phenomenon. If they agree I throw the model away because it is trivial, if it does not I throw it anyway. I'm puzzled. More seriously, the first model dates back to 1896. Not enough subsequent data to test it? Yes, of course. It has then be refined and tested again, and so on for many decades. Apparently you're seing just last generation of models, as if they came out of nowhere. -
mistermack at 04:44 AM on 27 October 2010Models are unreliable
To answer the point about physics and chemistry, it's stretching it rather a lot to say that since the models involve (or are based on) physics and chemistry, they must be right. Bridges fall, buildings collapse. Shuttles explode. Their design is always based on maths, physics and chemistry. They can get it wrong. But we have long experience of successful building. We have zilch of successful climate forcasting. So I think I'm right to be sceptical of the models' ability to get it right at this stage.Moderator Response: You are incorrect that we have "ziltch" experience in successful climate forecasting. You really should actually read the posts. Be sure to click the "Intermediate" tab. -
mistermack at 04:33 AM on 27 October 2010Models are unreliable
Mueoncounter, my point isn't that we shouldn't have models, or that you shouldn't seek to improve them by using previous data. I take all that as obvious. My problem is that when I look on this site, or anywhere, for good evidence that manmade CO2 is going to cause significant harm, the only evidence of any significance is that the models match the data, or the data matches the models. Since the models are developed to match the data, what do they expect? Don't quote it as evidence, that's all I'm saying.Moderator Response: The models are not developed merely match "the data" in the pejorative sense you are using the term "the data." Please actually read the material that I and others have pointed you to, for explanations of exactly how observations are used in model construction. Your mere repetition of your contentions is not contributing to the discussion. -
PeterRossy at 04:33 AM on 27 October 2010Antarctica is gaining ice
He wasn't able to tell certanly that global warming was the reason but the ice weight loss from Antarctica is being influenced by warm water temperatures, which in turn are caused by climate change and altered ocean currents. The losing of ice is thought to be partly attributable to the processes that take place over thousands of years. “How it reponds to climate takes place over many different time scales,” Professor Bamber said. “There are changes taking place now that are a result of what happened to the climate 12,000 years ago.” Athmosphere thermal rises are caused by climate change are more visible at the poles than in other regions of the world but researchers have an incomplete understanding of the mechanisms controlling ice in Antarctica. -
The Inconvenient Skeptic at 04:30 AM on 27 October 2010Measuring CO2 levels from the volcano at Mauna Loa
The only problem with the Mauna Loa station is the spelling. Otherwise it provides solid results on the global CO2 levels. It should also be noted in later versions that the US typically has higher levels of CO2 than the station in Hawaii. In fact, most industrial countries have higher levels than the middle of the Pacific Ocean. -
RSVP at 04:27 AM on 27 October 2010Waste heat vs greenhouse warming
KR #344 I agree analogies are not one to one. -
muoncounter at 04:21 AM on 27 October 2010Models are unreliable
#253: "told you to pick the next Kentucky Derby winner" That would be akin to predicting the next hurricane's landfall location from a study of prior landfalls. A more reasonably-posed analogy might be to conclude from a study of prior races that there are factors that categorizes the field of entrants into 'likely' winners and 'likely' losers (forgive my alarmist language). For example (from wikipedia): "No horse since Apollo in 1882 has won the Derby without racing at age two." That would make a 'very unlikely' outcome. So from a study of climate, it is perhaps unreasonable to predict a specific heat wave, but not at all unreasonable to build a model that says: "would these [extreme weather] events have occurred if atmospheric carbon dioxide had remained at its pre-industrial level of 280 ppm?", an appropriate answer in that case is "almost certainly not." But what is all this about models not having a peek at prior data? On another thread, there have been comments to the effect that models and evidence somehow pollute each other; that makes no sense to me. What use is a model if it is not built on prior data and tested by subsequent data? -
RSVP at 04:20 AM on 27 October 2010Waste heat vs greenhouse warming
CBDunkerson #342 "Please explain what mechanism you think exists which similarly constrains the outflow of energy from the Earth to a fixed amount." In the third paragraph of #341 I already say that outflow does not only depend on temperature, but also the size of the Earth or more precisely its surface area (which is actually finite believe it or not), plus not everything has the same emissivity, especially the different gases we are breathing all day. It would be interesting to know if you think waste heat could ever cause global warming if CO2 concentration were at its pre Industrial Revolution level. In other words, if there was no anthropogenic CO2 accumulated. Try to imagine that man was still somehow dumping the same 0.474 x 10E21 J of waste heat into the environment each year without the CO2. (Say all nuclear or something.) As calculated above, this is enough energy to raise the temperature of the atmosphere 0.1 degrees in one year (assuming no losses). However, it is fair to assume that some of this energy would immediately begin to thermally radiate and be lost forever, such that after one year the atmosphere's temperature only gets raised 0.01 degrees, or 0.001 degrees. At this point in the discussion it doesnt seem like the number matters, since from what I can tell no one has admitted that this energy could possibly accumulate. You have to remember there is no waste heat night. It never stops, and has generally been on the increase. (see graph at the top of this page) http://en.wikipedia.org/wiki/World_energy_resources_and_consumption -
Daniel Bailey at 03:47 AM on 27 October 2010CO2 lags temperature
Re: Tom Dayton (149, 203) and mistermack (150, 204) Interesting & germane new article out in nature geoscience today, "Southern Ocean source of 14C-depleted carbon in the North Pacific Ocean during the last deglaciation". Germane, as it adds weight and evidence to the "burp" mechanism under discussion. Interesting also was the development of neodymium isotope values as a proxy. Science Daily write-up here. The Yooper -
DSL at 03:23 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
And to follow up on BP, here's at least one place where the burning of G&T takes place. -
JMurphy at 03:20 AM on 27 October 2010Models are unreliable
Oops, sorry - half my links were already in the green box. Sorry ! -
JMurphy at 03:18 AM on 27 October 2010Models are unreliable
mistermack, as well as looking at the Moderator's comment, you can investigate models further in WIKIPEDIA (Climate Models, Global Climate Models), NASA (The Physics of Climate Modeling), and THE DISCOVERY OF GLOBAL WARMING (Simple Models of Climate). How could the first models have peeked at the previous data ? You're right about one thing, though, they aren't just constructed using the laws of physics : there's a lot of maths in there too, as well as some chemistry. -
JMurphy at 03:01 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
mistermack wrote : "If I saw this suggestion, about the second law, my initial reaction is that it's laughable, and not worth answering." Most so-called skeptical 'arguments' are laughable (as are most of those bringing them forth, e.g. Monckton), but if they are not responded to - and dismissed as the laughable nonsense they are - the so-called skeptics claim that as being a victory and 'proof' that AGW is false. Many of those 'arguments' are now regarded as zombies because, no matter how many times they are refuted, they keep coming back from the dead. But continually refuted they must be. The same goes for the laughable 'arguments' from creationists - if they weren't shown as false, more and more people would believe there was something to them, and there are more than enough people who believe that creationist nonsense as it is ! -
mistermack at 03:01 AM on 27 October 2010Models are unreliable
Jmurphy, do you really believe that the models are just constructed from the laws of physics? Someone sat down with a physics textbook and developed the current models? Without peeking at the previous data even once? "based on" is a meaningless phrase here.Moderator Response: Look in the green box at the bottom of this Argument--the box labeled "Further Reading." Click those links. You will learn how physics is used in the models, and how and to what degree observations are used. -
The 2nd law of thermodynamics and the greenhouse effect
BP, No, I didn't have anything specific in mind. My issue is that you implied a few times that the most likely scenario following a change in the climate landscape would be a return to an entropy maximum with a total rate of entropy production exactly equal to the previous local maximum. I don't see why you would get the impression that such a change would be the most likely scenario. In fact, given that the unknown future maximum could be either lower or higher to some degree, it is extremely unlikely that the new maximum will just happen to be identical to the previous maximum (or any specific value). You have repeated a few times that - given the MEP principle - a negative feedback is likely. I don't see any basis for this implication. MEP alone neither supports nor contradicts AGW. To suggest that MEP predicts a negative feedback is to assume that the climate will be able to arrange itself in a way that a) increases the earth's entropy production and b) is impossible today or would not lead to entropy increase today. In other words, your argument is in the exact same place it was before invoking MEP; you are proposing that some as yet unknown or misunderstood mechanism may kick into effect that will negate or diminish GW. All you are really doing is restating that hypothesis in terms of entropy and MEP rather than thermodynamics. That doesn't change the fact that we need some evidence before assuming such a mechanism, or even implying that such a mechanism is likely to exist. In fact, MEP reduces the probability that such a mechanism exists, since it adds an additional constraint to the nature of this mechanism, i.e. it is impossible today or would not lead to entropy increase today. -
The 2nd law of thermodynamics and the greenhouse effect
I'm not terribly worried about the skeptical blogs, either - they tend to be self-selecting for the already convinced. But the amount of general press this horrid (and yes, laughable) article got made it significant enough to respond to. -
JMurphy at 02:50 AM on 27 October 2010Models are unreliable
mistermack, are you suggesting that the hypothetical model for the Kentucky Derby would be based on the laws of physics ? -
mistermack at 02:47 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
Well, that' my problem then. I don't know any sceptical blogs. I'm sure they contain some crazy stuff. If I saw this suggestion, about the second law, my initial reaction is that it's laughable, and not worth answering. -
The 2nd law of thermodynamics and the greenhouse effect
mistermack - This particular skeptical argument was hardly hidden away somewhere. I believe that it was discussed on almost every climate blog for about 10 months over the last year. That includes ScienceOfDoom, Deltoid, ClimateRealists, bunches of others. It also made it into any number of news outlets as mentioned by skeptic columnists. Try googling the authors and see. It didn't die down as a heavily promoted anti-AGW argument until several rebuttals appeared (including a peer reviewed one, Halpern 2010, which I believe was about the only citation for the Gerlich article). This particular argument against global warming was idiotic, but hardly a strawman, given the attention paid to it on the skeptic front. -
archiesteel at 02:40 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
@mistermack: "Find a pathetic argument, hidden away somewhere, and debunk it. That's a strawman tactic to me." We don't "find" that pathetic argument, it is brought up by some contrarians. I would rather never hear about it again. A strawman is attributing to someone an exaggerated version of their position that is easy to debunk. That's not the case here - some (not all) contrarians really do argue this. Note that nowhere did anyone here suggest that *all* skeptics believe this. However, it is undeniable that some do, and as the goal of this site is to list *all* arguments used by those challenging AGW theory, then this one must be included as well. -
archiesteel at 02:24 AM on 27 October 2010Models are unreliable
@mistermack: false analogy. If you don't put your money on the horse (i.e. you don't trust the models), you are unaffected whether it wins or loses. Your life goes on as normal. If don't "put money" on AGW (i.e. disbelieve the experts) and it turns out to be true - as the body of science strongly suggests - then you'll be affected. A better analogy would be if someone kidnapped a loved one, told you to pick the next Kentucky Derby winner, and warned you they'll kill the hostage if you pick the loser. Which horse would you pick then? The favorite (i.e. the one the experts say has a better chance of winning than the others according to odds calculations), or a long shot that experts say is unlikely to win? -
mistermack at 02:23 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
I wrote "I've never read it till now". I didn't think it had never been written, just not widely argued, or taken seriously. To qualify as being a strawman, it doesn't have to be brand new. You can find strawmen, you don't have to invent them. Find a pathetic argument, hidden away somewhere, and debunk it. That's a strawman tactic to me. -
archiesteel at 02:14 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
@mistermack: I myself have heard that argument during debates against people opposed to AGW theory. Can we put you on record as agreeing that the greenhouse effect *doesn't* violate the 2nd law of thermodynamics? It'd be nice for us to agree for a change. :-) -
Berényi Péter at 02:11 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#69 mistermack at 00:34 AM on 27 October, 2010 Seems like a great big straw-man to me Here is the paper nealjking says went down in flames. International Journal of Modern Physics B (IJMPB) Condensed Matter Physics; Statistical Physics; Applied Physics Volume: 23, Issue: 3(2009) pp. 275-364 DOI: 10.1142/S021797920904984X FALSIFICATION OF THE ATMOSPHERIC CO2 GREENHOUSE EFFECTS WITHIN THE FRAME OF PHYSICS GERHARD GERLICH & RALF D. TSCHEUSCHNER -
mistermack at 02:10 AM on 27 October 2010Models are unreliable
Suppose they took the world's best computers, and the best modellers, and worked on the last twenty years Kentucky Derby results and form. Eventually they produce a model that predicted them all. Would you sell your house, and put the money on the same model's prediction for the next Kentucky Derby? -
DSL at 01:14 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
You haven't read much, then, have you mistermack? It's a thread on almost every denialist site. Here's one. Also, your claim of (great big) straw man implies that you have an alternative theory to protect against such attacks. Is this true? Where is it? Or are you simply representing the denial-o-sphere as a (internally inconsistent) whole? -
nealjking at 01:13 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#69, mistermack: Gerlich & Tscheuschner wrote a paper that claimed that. It got published, but the general consensus is that it went down in flames. -
JMurphy at 01:04 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
mistermack, you should spend some more time at Jennifer Marohasy's site, if you want to find out where that non-strawman came from. Or have a look at the 'Skeptic Links' at this link on Skeptical Science. You could have found that one yourself by searching... -
The 2nd law of thermodynamics and the greenhouse effect
mistermack - Google the horror that is "Gerlich and Tscheuschner". They claimed that the radiative greenhouse effect violated the 2nd law of thermodynamics. They were wrong, of course, and their physics were appalling. But their article, published as an editors choice (i.e. not peer-reviewed) in a low impact off-topic journal, got waved about by certain skeptics for quite some time. It was very sad... I shed some tears for the educational system during that time. On the plus side, a lot of people had a chance to learn some basic physics during the arguments, and some of the more competent scientific skeptics, such as Roy Spencer, weighed in on the side of reason and dismissed it. -
mistermack at 00:34 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
"Skeptics sometimes claim that the explanation for global warming contradicts the second law of thermodynamics." Do they? I've never ever read that till now. Seems like a great big straw-man to me.Moderator Response: Many of the posts appearing on the home page recently have been posted there to call attention to that same material having newly been created and added to the regular set of "Arguments." You can tell by reading to the end of the home page's post where you will see a green box which, in this case, states "This post is the Basic Version (written by Tony Wildish) of the skeptic argument 'The 2nd law of thermodynamics contradicts greenhouse theory'." Each of those regular Arguments begins with an orange box with a quote and link to a skeptic making that skeptic claim. -
Ken Lambert at 00:30 AM on 27 October 2010It's the sun
Gentlemen Regarding the numbers I am currently crunching (Ref #651)- could anyone point me to some historical data on Wate Vapor + Ice Albedo feedback - currently quoted by Dr Trenberth at +2.1W/sq.m in AD2005. I could assume linearity back to zero in AD1750 but this is a very significant component, and this could widely affect the result of the Total forcing sum. -
Waste heat vs greenhouse warming
Analogies and their issues; Analogies are fine when used to explain aspects of a complex system. They fail when you try to use them to disprove that complex system, because the analogy is not a 1-1 mapping. See a much more detailed posting here, motivated by similar logical issues earlier in this topic thread. I wouldn't bother to play the analogy game, CBD - that leads straight to this Bad Analogy error. If you want to disprove a theory or system, you have to do the work there, not in a made-up world whose parameters change with every reply. -
muoncounter at 00:27 AM on 27 October 2010Waste heat vs greenhouse warming
#336: "that energy being injected into the environment is having no impact, (instead of warming things, it hightails for the stars)" All energy injected into the environment does not hightail for the stars ... some of it is trapped (or at least stored temporarily) here in an atmosphere increasingly rich in GHGs. Of course, those same GHGs also trap some of the far larger supply of energy from the sun. But bottom line, RSVP is a warmist! -
The 2nd law of thermodynamics and the greenhouse effect
Berényi - I'll emphasize my primary point once more. To the extent (and this appears to be an interesting point of research) that MEP is a factor in climate dynamics, it's a factor not just in forcing deltas but in the state(s) prior to the forcing deltas. Therefore MEP is already part and parcel of the climate sensitivity to forcings. Not a new factor that will jump in, but an existing part of the system dynamics. That means that climate sensitivities to forcings still hold, that those measured 'black-box' sensitivities inherently factor in the MEP effects. -
muoncounter at 00:17 AM on 27 October 2010Measuring CO2 levels from the volcano at Mauna Loa
#13: "Do Mauna Loa and other stations measure the concentration of other greenhouse gases in the atmosphere?" Yes, although not all sites around the world measure all species. Look at NOAA's data viewer where you can select among CO2, CO, CH4, O3, SO2, NOx, etc. -
Berényi Péter at 22:01 PM on 26 October 2010The 2nd law of thermodynamics and the greenhouse effect
#66 e at 18:35 PM on 26 October, 2010 is it not possible that the rearranged landscape consists of a lowered local peak, rather than a translational shift of the landscape? It is certainly possible, but I don't see a compelling reason it should be so. Even for infinitesimally small increases of baseline opacity the transformation the landscape suffers seems to be of some more general form than simple downscaling. But I have not done a full mathematical analysis of the situation yet, it's just an impression. Do you have anything specific in mind? BTW, as I'm peeking into the literature, I see a widespread misconception about MEP-related role of radiative transfer in the climate system in general and about Dewar 2003 specifically. Stephen Mobbs is even enumerating in a presentation among Dewar's results the following proposition: "MaxEnt is equivalent to maximising the mean entropy production rate <σ> due to internal material processes – not including radiation [emphasis mine]" Journal of Physics A: Mathematical and General 2003, Volume 36, Number 3, 631 doi: 10.1088/0305-4470/36/3/303 Information theory explanation of the fluctuation theorem, maximum entropy production and self-organized criticality in non-equilibrium stationary states Roderick Dewar What Dewar actually says is this: "For climate systems there is an additional contribution to σΓ from radiative heating at planetary temperatures, deriving from the internal energy component of Q in equations (9) and (12). This contribution is not taken into account in the purely material entropy production of equation (15), and is in fact ignored in applications of MaxEP to the climate [16, 17]. Again Jaynes’ procedure provides the rationale for ignoring this contribution – radiative heating is reversible and does not contribute to the number of paths W(Airr<λ>) in equation (24). To summarise, in applications of MaxEP to climate systems it is the irreversible, material entropy production that is maximised." It is said in the context of interpreting Paltridge's work on application of MEP on horizontal heat transport (advection) and he just tries to justify why radiation was ignored in that work. Indeed, as long as radiative heating is supposed to be reversible, it does not give a contribution to the number of paths. However, while it might have been a reasonable approximation for the specific problem Paltridge was interested in, it surely does not hold in general. In a semitransparent medium (like air) whenever radiative exchange occurs between two parcels at different temperatures, the process is irreversible and involves entropy production. It may be negligible at the center of CO2 absorption band (at 15 μm) where mean free path of IR photons is small and nearby locations are at almost the same temperature, but as we move to the wings or even to an atmospheric window with no absorption lines at all just the H2O continuum, parcels at vastly different temperatures can get into radiative contact (like hot (-50°C) Antarctic winter troposphere with cold (-80°C) surface). If one is interested in climatic effects or the radiative properties of CO2, ignoring radiation entropy is certainly the most foolish track to take. As soon as we stop treating clouds, snow cover or ocean color (induced by biological processes, determining light extinction with depth) as boundary conditions, but include them as variables in the climate system, entropy production associated with ASR (Absorbed Shortwave Radiation) also enters the game. -
CBDunkerson at 20:23 PM on 26 October 2010Waste heat vs greenhouse warming
RSVP, ok I'll play... now its a dam. So in the scenario you posit with the "narrow slot" the outflow of water is constrained... the inflow can increase without the outflow increasing in turn (until the water level rises so high that it overtops the dam). Please explain what mechanism you think exists which similarly constrains the outflow of energy from the Earth to a fixed amount. Also, decreasing the outflow by 100x is still going to cause the temperature to rise one hundred times faster than increasing the inflow by 1x. So we're still looking at AWH warming being an insignificant factor unless your unexplained mechanism for constraining radiation outflow is itself somehow immune from being blocked by greenhouse gases. So there you go. Your analogy can work. You just have to explain two little things which violate the laws of physics as we know them. -
The 2nd law of thermodynamics and the greenhouse effect
BP >If there is a maximum entropy production principle at work indeed, for a neutral feedback you need the same climate state to be found right at a peak on the rearranged landscape, which is extremely unlikely. Correct me if I'm missing something here: is it not possible that the rearranged landscape consists of a lowered local peak, rather than a translational shift of the landscape? In such a case, we would expect a neutral response since we would already be at the local peak. If so, is it not invalid to assume that neutral feedback is "extremely unlikely?" -
RSVP at 18:29 PM on 26 October 2010Waste heat vs greenhouse warming
CBDunkerson #340 You are correct about a lake with the topology you assume. In mine, the outflow is restricted through a narrow slot, and likely isnt too common in nature, but is possible. I should have said "dam", my bad. But now that you have taken up the point, it looks like there are two things to consider as far as the comparison with global warming. In the lake or dam, the rate of level change will depend on three things. How much water this new "spring" represents, the uptake capacity, and to what extent the outflow will increase as a result of an increase in height. This increase must be less than the source influx. This last factor seems to be key, and unless this is determined, I dont see how anyone can claim to be in a position of certainty. The question is really not whether it is accumulating. The question is how fast. All I am hearing is that radiation increases as the fourth power of temperature. If things were that simple, you wouldnt have to increase the size of an audio amp's cooling fins as a function of power rating. In the same way, the Earth's thermal radiation capacity is limited by the size of the Earth and any and all properties that affect its total emissivity. e #337 What I explain above applies in the same way to what you bring up here. You seem to have ignored the words "in a way that exactly compensated...", which implies a difference that accounts for energy that is "temporarily" being stored. And "temporary" really means "permanant" as long as the additional flux is present. -
Berényi Péter at 16:54 PM on 26 October 2010The 2nd law of thermodynamics and the greenhouse effect
#63 KR at 13:28 PM on 26 October, 2010 Currently we are moving towards (but have not reached) an equilibrium - but a 'steady-state' system will still reach an entropy balance (dynamic equilibrium) where energies do not change I think you still don't get it. Here is a readable account on MEP (Maximum Entropy Production), SOC (Self-Organized Criticality), including toy models like Sandpile Avalanche Dynamics and FT (the Fluctuation Theorem). Non-equilibrium Thermodynamics and the Production of Entropy Understanding Complex Systems, 2005, 2005, 41-55 DOI: 10.1007/11672906_4 4 Maximum Entropy Production and Non-equilibrium Statistical Mechanics Roderick C. Dewar Critical systems' scaling behavior is well understood in physics. If the majority of climate scientists think climate is somehow different with a very special structure that invalidates general principles, they have to explicate this idea clearly, simple hand waving like in Ozawa 2003 would not suffice. -
Kooiti Masuda at 16:21 PM on 26 October 2010The 2nd law of thermodynamics and the greenhouse effect
Concerning thermodynamics, we have several different levels of knowledge. 1. Equilibrium thermodynamics. We can compare two states of thermodynamic equilbrium of the same system, and tell in which direction spontaneous changes can occur. But this formulation cannot usually describe the processes of the changes which are non-equilibrium. 2. Local thermodynamic equilbrium. While the climate system as a whole is clearly not in a thermodynamic equilibrium, we can define thermondynamic quantities such as temperature in a certain spatial and temporal scale, which is much larger than individual molecules and individual collisions between molecules, but much smaller than the whole atmosphere. If we smooth out the microscopic variabilities, the thermodynamic quantities can be considered as functions of macroscopic space and time coordinates. (This condition does not hold in the upper atmosphere, but acceptable for the troposphere and the stratosphere.) 3. Formulation of non-equilibrium thermodynamics. We can describe the rate of change of entropy in the climate system or a certain subsytem of it as the sum of entropy exchange and entropy production. Entropy production must be positive. There is no other formal constraint at this level. 4. Dynamic steady states in the entropy balance. The climate system can be approximated as a steady-state system which exports as much entropy as is produced within it. The system may actually fluctuate around the steady state. If the external condition changes slowly, the state of the system will drift acoordingly, but it may still be be approximated as a steady state. If the external condition changes too fast, the state cannot be considered as steady. 5. The hypothesis of maximum entropy producition. Under a certain external condition, there is a range of approximately steady states which our system can take. Among them, the state which has the maximum rate (=quantity per unit time) of entropy production is likely to be realized. I think that the items 1 and 2 are shared by effectively all physical climate scientists, and that 3 and 4 are acceptable by the majority of them (though many of them do not conceive them by themselves), but that 5 is held just by a minority among them. -
Daniel Bailey at 14:01 PM on 26 October 2010Measuring CO2 levels from the volcano at Mauna Loa
Re: Agnostic (13) Whenever I have a question (and having an enquiring kinda mind, I have many [questions, not minds; multiple minds would be silly, wouldn't it? Shut up and let the man talk!]), I like to go straight to the source. In this case, the Earth System Research Laboratory that operates the Mauna Loa facility in question. There one would thus find a full panoply of measurements of various and sundry greenhouse gases in full regalia. But that's me. As far as your last question, given your earlier worthy comment on that subject, that would seem to be a rhetorical question. But yes, that would be the reaction of sensible people. Which is why our politicos in America will procrastinate until it's too late. Prevention is out the window. All we will be able to do is to adapt as best able. Asbestos underwear, anyone? The Yooper -
Albatross at 13:59 PM on 26 October 2010Irregular Climate podcast 13
I really enjoyed listening to this today whilst doing some number crunching Excellent (and comprehensive) job guys. -
Jerry at 13:39 PM on 26 October 2010Measuring CO2 levels from the volcano at Mauna Loa
I don't think the sea breeze has much of an effect on Mauna Loa. What does have a big effect is the inversion layer. From their website "MLO also protrudes through the strong marine temperature inversion layer present in the region. This inversion layer acts like a lid and keeps the lower local pollutants below the observatory." I am not an expert but I do live in the area. Often the lower level winds and the winds aloft are blowing different directions, which can make for interesting cloud watching. Jerry
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