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Marcus at 16:23 PM on 27 October 2010What should we do about climate change?
John Chapman, there is nothing fanciful about concerns regarding the waste & terrorist implications of nuclear energy. The US has enormous problems dealing with the accumulated nuclear waste of the past 60 years, & it doesn't take much nuclear waste to build a dirty bomb. Not to mention the danger posed by the facilities themselves were someone to fly a plane into it! -
Bern at 16:22 PM on 27 October 2010What should we do about climate change?
Marcus, you don't happen to have a link to that info, do you? I'm curious if they discussed costs for any other electricity sources. I saw some numbers that suggested a modern coal-fired power station would cost only $1.50 or so per watt up-front, but would cost another $0.50 per watt per year in fuel costs (can't remember where I saw that, unfortunately). -
Marcus at 16:10 PM on 27 October 2010What should we do about climate change?
Well Barry, according to a talk given by G Poornima & L Isensee, the cost of installing a Concentrated Solar Power (as of 2009) comes out to between $2.50 to $4.00 per watt. By contrast, most nuclear power stations cost around $5.00 to $6.00 per watt to build-then have fuel & waste disposal costs on top of that! Its worth noting that the high cost of nuclear power comes even after *60 years* of development & many hundreds of billions of dollars in subsidies for the industry! -
Tom Dayton at 15:50 PM on 27 October 2010Waste heat vs greenhouse warming
Yes, RSVP, GHGs of course do slow the escape of waste heat. But GHGs do that equally as they slow the escape of heat from all other sources, including the Earth's heat resulting from incoming solar radiation. That's why the orders of magnitude lower quantities of waste heat make it inconsequential to worry about. That's also why GHG increase is consequential to worry about: GHGs slow the escape of heat from all sources. -
RSVP at 15:48 PM on 27 October 2010Waste heat vs greenhouse warming
#348 CBDunkerson (resending after cleaning up, and adding just a little more) The follow, http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law ...starts by saying... "The Stefan–Boltzmann law, also known as Stefan's law, states that the total energy radiated per unit surface area of a black body per unit time" note the words, "per unit surface area", and "per time" You are right in thinking along the lines "what goes up, must come down", but for some reason you are ignoring the idea that the time it takes to "go up, and down" could vary (depending on conditions). As I was saying about the heat sink on the back of an audio amp. They dont make them bigger for nothing. The more surface area, the faster the heat can radiate, so as to not allow the amp to overheat (for instance). Likewise to our earlier analogy, the viscosity of water is a real force that impedes flow. So in the same way they have to actually spend more money for larger pipes to get large amount of water to where it needs to go in a timely manner. http://en.wikipedia.org/wiki/Viscosity And more to the point, if the heat flow outward is being restricted by GHGs (and that is a big IF), it could only be helping the accumuation of waste heat. AND as the surface area of the Earth is finite, this will limit the amount of energy released per unit time. If you wait long enough. If there was a break in waste heat emmision, the Earth would have a chance to get rid of it, but we never stop emitting this heat. -
RSVP at 15:40 PM on 27 October 2010Waste heat vs greenhouse warming
#348 CBDunkerson The follow, http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law ...starts saying... "The Stefan–Boltzmann law, also known as Stefan's law, states that the total energy radiated per unit surface area of a black body per unit time" note the words, "per unit", "per time" You are right in saying thinking alone the lines "what goes up, must come down", but for some reason you are ignoring the idea that time it takes to "go up, and down" could vary. As I was saying about the heat sink on the back of an audio amp. They dont make them bigger for nothing. The more area, the faster the heat can radiate, so as to not allow the amp to overheat (for instance). Likewise to our earlier analogy, the viscosity of water is a real force that impedes flow. So in the same way they have to actually spend more money for larger pipes to get large amount of water to where it needs to go in a timely manner. http://en.wikipedia.org/wiki/Viscosity And more to the point, if the heat flow outward is being restricted by GHGs (and that is a big IF), it could only be helping the accumuation of waste heat. -
scaddenp at 15:12 PM on 27 October 2010What should we do about climate change?
"97% of climate scientists". If this is based on Doran, then the 97% is even tighter than that - climate scientists actively publishing on climate change. While this might be simplification for radio, I think it is overstating a case which I believe is poor practise. Leave that to denialists. If you overstate something, then it is easy for someone to discount your entire argument on basis of that error. On the other hand, if the argument is understated, then close examiners looking to refute your argument will find things worse than they thought - and perhaps pause to reflect.Response: If I'm crunched for space, I usually say "climate experts" and if someone asks "what's a climate expert?", I say a climate scientist who is actively publishing peer-reviewed papers on climate science. -
Barry Brook at 14:46 PM on 27 October 2010What should we do about climate change?
I'm curious to understand the justification and evidence for this statement: "... like solar-thermal generators that are now providing energy in Europe more cheaply than Nuclear generators" -
adelady at 13:49 PM on 27 October 2010What should we do about climate change?
John 97% of scientists? Should that be 97% of climate scientists or involved scientists or something. Or is that going to muck up your word count.Response: I'm just guessing here but I'd bet Kevin went with the simplification of "scientists" instead of "climate scientists" for the purpose of talking to a general radio audience. -
adelady at 13:48 PM on 27 October 2010What should we do about climate change?
John. Population? The real problem is consumption and associated waste (by humans). Was it here I read that ants have a couple of hundred times the biomass of the human population? They seem not to have run out of their resources. Probably because they reuse and recycle every single element required for life. Anyway, human population numbers will decline so long as the focus remains on educating girls and women. China's approach was probably the best they could do given the extreme problems they faced. But it was a disaster, and continues so, because of the failure to educate the population at large. The men and women who were born around the time the policy was introduced have been educated and acculturated to preference for male children and to desire 4 generations under one roof. http://www.thisis50.com/profiles/blogs/24-million-chinese-men-wont?xg_source=activity A system that encourages and supports later marriage and esp. later birth of a first child firstly reduces the generational overlap thereby reducing total population even with an unchanged birthrate. A policy and a program was necessary. This particular policy will continue to cause problems for a very long time. -
Joe Blog at 13:25 PM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
KR The second law is about entropy, heat flows from hot to cold is just sticking this in the most simple terms. If you state the second law as chaos increases, you are mostly just going to get blank stares back, but its not a bad approximation of the second law. But entropy increases or stays the same, is the second law... now if you modify the system however? -
Joe Blog at 13:14 PM on 27 October 2010What should we do about climate change?
In australia solar may be viable, but this is not true for every corner of the globe... There is nothing wrong with the fourth and fifth generation thorium salt fast breeder reactors. There is as much disinformation floating around about this technology as anything. And this does offer a viable alternative to fossil fuels anywhere. Thorium is cheap, they are vastly more efficient than heavy or light water reactors. And produce a fraction of the waste... If the world was serious about cutting its reliance on fossil fuels, this should be the first avenue of investment. -
John Chapman at 13:11 PM on 27 October 2010What should we do about climate change?
Using less energy can, at best, offset the increases in population and energy demands. While solar has a role, especially in WA, the global solution for energy has to be nuclear. Any concerns about waste or terrorism (fanciful) are insignificant compared to the consequences of global warming. The other action is to curb population growth. China, to their credit, at least has aggressive nuclear energy plans and is doing something about population. One of the benefits of not having a democracy - one can make unpopular decisions! -
The 2nd law of thermodynamics and the greenhouse effect
Albatross - I agree. Berényi - MEP discussions probably belong on How sensitive is our climate, not here. The 2nd law of thermodynamics is quite secure, and the nonsense of Gerlich and Tscheuschner well disproven. MEP is off-topic here.Moderator Response: Agreed. Take it to that other thread, please. -
Kooiti Masuda at 12:53 PM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
The message of the main text of this thread is that such assertion that "greenhouse effect contradicts the 2nd law of thermodynamics", as Gerlich and Tscheuschner made in their paper published in 2009, is false. I think that there is no objection to this message among the commenters here. The story of the principle of maximum entropy production (MEP) is related to the general title "The 2nd law of thermodynamics and the greenhouse effect", but MEP is something distinct from the 2nd law, and is much less estabilished. I think that it is an interesting subject of academic science to discuss whether it holds in the real world. But I think that formulations of the model systems that should represent the real world is different among scientists (e.g. between Berényi Péter and Ozawa et al.), and that the answer to the preliminary question "maximum among what?" is different accordingly. So MEP does not seem to me helpful as a piece of policy-relevant science of climate at present. -
scaddenp at 12:43 PM on 27 October 2010It's cooling
Adrian- well I expect that next La Nina will start the chorus "start of cooling trend" again - until the next El nino. Not a constructive way to look at it perhaps? Wouldnt it be better to look that the temperature and compare with temperatures the last time the world have a similar magnitude of El Nino/ La Nina? With a TOA energy imbalance, you need iron-clad wishful thinking to propose that we are going to get cooler. On the other hand, if you are prepared abandon your denialism if its warmer in 5 years, then that would be progress. -
Craig Allen at 12:40 PM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Oops, sorry for assisting Adrian to take the tread off-topic. The page that JMurphy links to is the most effective response. -
Craig Allen at 12:34 PM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Adrian Smits #4 And according to UHA January 2010 was the hottest January in the 32 year satellite record, August was the second hottest month, and 2010 was the second hottest year, and we have just seen the hotest decade, yada yada yada. But rather than cherry picking hot or cold periods within the dataset how about we consider the trend over the entire record. It is clearly positive and recent data in no way contradicts that long-term trend.Moderator Response: Please respond on the appropriate thread. See comments by readers and moderators above. -
Albatross at 12:29 PM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Mike @9, Good point. It is rather unfortunate that so much emphasis is placed on 2100 and doubling CO2. Hopefully the IPCC will rectify that in AR5. I'm not sure that +6 warming for doubling CO2 is the most likely scenario-- +3 C seems the most likely. That said, the IPCC might need to entertain other scenarios which allow for the fact that CO2 levels (or equivalent) will likely treble over pre-industrial levels circa 2100. -
JMurphy at 12:14 PM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
I have replied to adrian smits on the Is Global Warming Still Happening ? thread.Moderator Response: Thank you! -
JMurphy at 12:12 PM on 27 October 2010It's cooling
adrian smits wrote (on the Isn't global warming just 2 °C and isn't that really small? thread) : "According to UHA satellite data the last week hasn't been this cold in many years for this old rock and I expect before this la Nina ends its gonna get a lot colder yet! Lets just wait 4 maybe 5 more years and see where we are at before doing anything rash.After 14 years of nearly flat temperatures that's 1996 to now. Three or four years of actual cooling should put a stake in the heart of the AGW agenda." Firstly, could you provide the link to that amazingly devastating data ? (Well, you seem to think it is) Secondly, last month was higher than the same month of the previous year, as was every other month - and, generally, some of the highest ever recorded. Where is the cooling you believe in ? Thirdly, are you agreeing that if there are 4 or 5 more years of warming, you will finally admit that your so-called skepticism has been wrong ? Fourthly, you have already been shown to be wrong about your belief in cooling over the last 14 years, but perhaps you have some hidden evidence you would like to show ? If so, please prove that your belief has some substance. Lastly, what do you believe this hidden agenda is ? Some sort of conspiracy ? -
Yvan Dutil at 11:41 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Adrian Smits, No obvious increase for a entended even if this was a real phenomenon, whould by no mean confirm than the heating is no longer ongoing. In non linear system, increase are done in step. See http://www.pnas.org/content/105/38/14308.fullModerator Response: The other, relevant, thread, please. -
Albatross at 11:18 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Adrian Smits, Your post is off-topic. Anyhow, lower tropospheric temperatures inferred from AMSU data are still running above average (with respect to the mean calculated over the satellite record). Regardless, short-term variability/noise is a distraction from the long-term warming trend. And yes, temperatures have been rising since 1996. See Hansen's latest paper. Ironic that in response a post where the author is talking about temperature changes over many thousands of years and you choose to post about the change in global temperatures in the last couple of weeks. Anyhow, until a couple of weeks ago the UAH data for the mid troposphere were at record highs. The very recent decrease in positive global temperature anomalies of late is because the atmosphere is finally responding to the strong La Nina event. And there is no "agenda" here, just science, please take your rhetoric and spin and agenda somewhere else.Moderator Response: The other, relevant, thread, please. -
archiesteel at 11:17 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Sorry for the off-topic reply, I hadn't seen John's response to adrian's comment. -
archiesteel at 11:16 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
@adrian: "According to UHA satellite data the last week hasn't been this cold in many years" Are you *really* going to gauge future climate from *one week* of data? "After 14 years of nearly flat temperatures that's 1996 to now." Hardly. Using the same UAH (not UHA) data:"Three or four years of actual cooling should put a stake in the heart of the AGW agenda." Considering we've had about 40 years of warming, we should have expected the spectre of climate change denialism to never again rear its ugly head, but I guess there's no rest for the wicked...
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The 2nd law of thermodynamics and the greenhouse effect
BP, ok sorry I misunderstood the water vapor point somewhat. RE the convention of moving along the landscape vs. changes to the landscape: it seems to me that distinguishing these concepts is somewhat important to your hypothesis is it not? MEP states that the system will tend towards the maximum path of entropy production given the constraints. As I understand it, it says nothing about whether a change in constraints can raise or lower the entropy production of the system. If positive feedbacks are thought of as changes in the constraints of the system (as the net consequence of the initial forcing), then there is no reason to predict that entropy production must increase (or stay the same) as a result of these changes. In this way, positive feedbacks can reduce entropy production with no contradiction to MEP. In short, how do you determine whether positive feedbacks are changes to the path of entropy production or changes to the constraints of the system? -
adrian smits at 11:03 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
According to UHA satellite data the last week hasn't been this cold in many years for this old rock and I expect before this la Nina ends its gonna get a lot colder yet! Lets just wait 4 maybe 5 more years and see where we are at before doing anything rash.After 14 years of nearly flat temperatures that's 1996 to now. Three or four years of actual cooling should put a stake in the heart of the AGW agenda.Response: Your assertion of "14 years of nearly flat temperatures" is discussed in "Phil Jones says no global warming since 1995" as well as "It's cooling" or even "It hasn't warmed since 1998". Please take that discussion to a relevant thread. -
Albatross at 10:29 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
KR @93, I have been following this debate with interest from the side lines. I think your last sentence sums everything up nicely-- a very elaborate red herring at that. So this "debate" all seems an effort by BP to distract form the subject at hand. Or does BP agree with G&T's misunderstanding that the so-called "greenhouse effect" somehow contradicts the second law of thermodynamics? There is really nothing to debate concerning the validity of G&T's work, b/c the science on that is settled-- G&T have been shown to be wrong. If BP is trying to argue that the climate system has some alleged significant negative feed backs, surely that debate belongs on a more appropriate thread, and not here. -
scaddenp at 10:26 AM on 27 October 2010Blaming global warming on the oceans - a basic rebuttal
Joe, I have no doubt about the importance of ocean in climate mechanisms (why else include oceans in climate model) but I do not think you can attribute climate change on current scale to UNFORCED change in ocean circulation. As to higher glacial max T with lower CO2, I would point out that glacial cycle is very slow with time for equilibrium. Climate is currently out of equilibrium with forcing. (note TOA energy imbalance). Given ocean mixing rates, I find it hard to see how ocean can equilibrate to current CO2 forcing in much less than 1000 years. -
The 2nd law of thermodynamics and the greenhouse effect
Berényi - Once again you are proposing a complex hypothesis of negative feedback that will defeat global warming: "This rearrangement would counteract GHG effect on entropy production rate (like a negative feedback)". And once again this is contradicted by the actual data. Such a MEP effect would already be in effect now, and in the past, and would be part of measured climate sensitivities. There is no such negative feedback observed in the data. And if your hypothesis is contradicted by the data, it's time for a new hypothesis. This entire MEP side excursion is a red herring. -
Joe Blog at 09:46 AM on 27 October 2010Blaming global warming on the oceans - a basic rebuttal
scaddenp at 07:54 "since oceans cant generate heat, then heat from oceans cant be forcing only a mechanism." This is simply not true,the rate of evaporation/water vapor, is dependent on the ocean surface T, the ocean surface T is a product of solar heating/back radiation/ back radiation is a product o atmospheric T, which is a product of ocean T/energy export in to the atmosphere, and the thermal characteristics of the atmosphere... the real variable being water vapor/or surface of the oceans T. So if you change the energy distribution around the globe, by moving energy from below the surface in the tropics to the surface at higher latitudes, you can force a change... By raising the average surface T, you raise the average evaporation/and the average GHE, and the back radiation will increase in line with atmospheric T's... you are going to have a hard time explaining past interglacial max T's without taking this into account... CO2 levels were lower, but T's were higher... You are assuming that its a linear relationship between surface T's and oceanic T profiles. -
MarkR at 09:46 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Joe Blog, I will clarify this later. What I meant was that 2 C global warming from today's level would put us beyond what appear to have been the warmest temperatures of the past 600,000 years. Which is one reason why we're not sure about feedbacks beyond that point! -
Berényi Péter at 09:45 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#90 e at 08:30 AM on 27 October, 2010 You're basically saying that an increase in water vapor is a decrease in entropy, so this feedback is impossible given MEP. No, I would never claim such a thing. Water vapor is free to do whatever it is inclined to. I just say given MEP some rearrangement of the climate state is likely in response to increased IR opacity in order to approach maximum entropy production rate under the new circumstances. This rearrangement would counteract GHG effect on entropy production rate (like a negative feedback). Water vapor redistribution is just a possibility. Average opacity of the atmosphere can decrease happily in weak H2O IR absorption bands even with increasing average moisture, provided its distribution gets a bit more uneven (higher moments are increased). It can happen on all scales, including sub-grid ones relative to computational climate models. how do you distinguish between a movement along the potential entropy production landscape, and a wholesale change to that landscape? It is a matter of convention to some extent. What you usually consider a forcing is supposed to rearrange the landscape while so called feedbacks only push the climate state around in the phase space. Is it simply a matter of external forcings vs. internal? If so, is not the ocean "external" with respect to the atmosphere? I don't think there are internal forcings, I would rather call changes not forced by external agents unforced ones. As the climate system is close to a critical state (see SOC - Self-Organized Criticality) one would expect the correlation length go up implying large spontaneous (unforced) fluctuations on all scales. And no, the ocean is in no way external to the climate system. In fact most of the climate happens in the oceans, there's thousands of times more mass in them than in the atmosphere. -
Albatross at 09:06 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
Hi MarkR, In the above figure looks similar to what Lindzen showed in his debate against Dessler to try and convince people that there is no reason for alarm ;) Joe Blog, "show most o the past interglacials warmer than this one" Well, maybe not by 2100....we are probably going to be experiencing a super interglacial. According to Petit et al. (1999) previous inter-glacials were about +2 to +3 warmer than at the time of the most recent stratum in the core (circa 1950 if I remember correctly). We are probably in for at least another +2 C warming. Now, what were sea levels during those previous inter-glacials? -
Berényi Péter at 08:48 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#88 Riccardo at 08:14 AM on 27 October, 2010 What do you mean by "everything else held constant"? I mean what is ordinarily called a no feedback situation. That is, cloudiness, snow cover, atmospheric water vapor distribution, winds, ocean currents, vegetation, etc. are not allowed to change in response to increased IR optical depth. I say in this specific case entropy production rate gets smaller than it was before optical depth was increased. And the entropy production rate of what, in first place? The global entropy production rate in W/K, measured as difference between entropy of outgoing longvawe vs. incoming shortwave radiation. Can't you increase entropy production rate by increasing surface temperature? No, I can't. Not as if I have not tried, but all simplified radiative or radiative-convective models I have checked so far have this vexing property. As surface temperatures are increased, entropy production rate declines. I conjecture a general principle is at work in the background. The MEP usually also implies minimum entropy contents of the system and higher temperatures mean higher entropy. But I do not have a formal proof (yet). Anyway, if you could show us an understandable climate model that goes against this conjecture, that would be informative. I've never heard anyone claiming the impossibility of positive feedback based on MEP principle You are welcome :) -
The 2nd law of thermodynamics and the greenhouse effect
BP, Ok, I think I see what you're doing. You're basically saying that an increase in water vapor is a decrease in entropy, so this feedback is impossible given MEP. Of course, if this claim was true, atmospheric water vapor could never increase. Of course, we know from empirical evidence, that water vapor does increase. In a more general sense, how do you distinguish between a movement along the potential entropy production landscape, and a wholesale change to that landscape? Is it simply a matter of external forcings vs. internal? If so, is not the ocean "external" with respect to the atmosphere? -
Daniel Bailey at 08:23 AM on 27 October 2010Medieval Warm Period was warmer
Re: Heidi (12)"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."
I am in 100% agreement with you on this one. The vast sea of humanity, frankly, doesn't give a darn about climate change nor is equipped with the background to understand it even if served up in bite-sized sound bites on the evening telly by the talking head du jour. The majority of people in this world are quite rightfully concerned with such mundane things as a roof over their heads, jobs that put food on the table, the health of their children or aging parents or just being frightfully occupied with the fight for survival itself. And I do not blame them for those preoccupations."Ultimately, of course, you will need to bring us along with you to achieve significant policy change... Is that the goal of this website?"
John specifically spells out the goals of this website here. Not to put words in his mouth (but since the vast majority of infrequent visitors never click on links provided), but this site exists as a repository for the truth about things climate. There exist so many active disinformation sites that exist solely to deceive the unwary and uneducated that there must exist some bastion of truth to fight against the darkness being imposed on science. Those seeking the truth on various matters related to climate can come here, examine the evidence (pro and con), and make up their own mind. What they do with the information they take away is up to them. Significant policy change would be nice, but is only achievable if enough sleepers awake to fight back and make a difference before it is too late to do so. But, hey, a journey of 1,000 miles starts with but a single step, right? The Yooper -
Berényi Péter at 08:18 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
#87 e at 07:43 AM on 27 October, 2010 the plain reading of this comment is that you were saying exactly what I accused you The key phrase is you need the same climate state to be found right at a peak on the rearranged landscape (otherwise there is a direction in the phase space along which a small displacement of the climate state would increase entropy production). I have no idea how "a total rate of entropy production exactly equal to the previous local maximum" would follow from it. But maybe I was not clear enough. -
Riccardo at 08:14 AM on 27 October 2010The 2nd law of thermodynamics and the greenhouse effect
Berényi Péter #85 there's something I don't get in your point #1. What do you mean by "everything else held constant"? Will you let the system evolve? By changing what? And the entropy production rate of what, in first place? Also, in #3 I do not understand why restoring the "right" entropy production rate cannot be a positive feedback in climate terms, i.e. an increase in surface temperature as opposed to in entropy production rate. Can't you increase entropy production rate by increasing surface temperature? Maybe it's just a consequence of the problem in #1. I've never heard anyone claiming the impossibility of positive feedback based on MEP principle. -
Joe Blog at 07:52 AM on 27 October 2010Isn't global warming just 2 °C and isn't that really small?
"Ice and sediment cores suggest we haven’t been this warm in at least 600,000 years so we’re not sure – but this could trigger a lot more warming." Really? all the ice core and sediment reconstructions ive seen show most o the past interglacials warmer than this one.... i think you may mean co2 levels ;-) -
The 2nd law of thermodynamics and the greenhouse effect
BP, I was referring specifically to this comment: >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. All other positions would involve some negative feedback and there is no room for a positive one at all. If you misspoke, then that's fine. But the plain reading of this comment is that you were saying exactly what I accused you of claiming: that negative feedback is the only probable outcome assuming MEP. Please don't accuse me of constructing strawmen when I'm responding directly to a statement you made. -
CBDunkerson at 07:24 AM on 27 October 2010Waste heat vs greenhouse warming
RSVP #345: First, nothing in your reply explains why the radiation outflow from the Earth would have a fixed limit... without such an explanation your analogy has no relation to reality. If your reference to the surface area of the Earth being finite was meant to be such... I'm hard pressed to believe even you can take that argument seriously. The more energy coming into a system, regardless of its size, the more energy must go out. Otherwise we've got energy magically ceasing to exist. "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." Can't have been too interesting... given that I already answered that question earlier in this thread. "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." Correct, waste heat cannot possibly accumulate in the climate system. Again, barring some explanation for why an increase in energy input would NOT result in a corresponding increase in energy output (the 'narrow slot' in your dam analogy) it is impossible for any such input to 'accumulate over time'. The current waste heat level causes a temperature increase, which causes greater radiation outflow, which prevents any further temperature increase. -
Tom Dayton at 07:17 AM on 27 October 2010Models are unreliable
mistermack and BP, there is an example of parameterization at Science of Doom's page CO2 - An Insignificant Trace Gas? Part Four. -
muoncounter at 07:07 AM on 27 October 2010Measuring CO2 levels from the volcano at Mauna Loa
#17: "most industrial countries have higher levels than the middle of the Pacific Ocean. " Excellent: Direct, verifiable, repeatable experimental evidence of the fact that atmospheric CO2 increases because of fossil fuel consumption. -
muoncounter at 07:02 AM on 27 October 2010Models are unreliable
#266: "Sub-grid processes, aerosols and the like are always parametrized in models, ... chosen to reproduce the past" Do you have a better procedure in mind? On the same page, von Neumann also said "I think that it is a relatively good approximation to truth — which is much too complicated to allow anything but approximations — that mathematical ideas originate in empirics." -
Tom Dayton at 07:01 AM on 27 October 2010Models are unreliable
BP, parameterization is not as freewheeling as you imply. See the RealClimate FAQ section "What is tuning?" and even the Wikipedia entry on parameterization (climate). Also see the list of parameters at climateprediction.net. -
The 2nd law of thermodynamics and the greenhouse effect
Berényi - "If you still maintain there must be a positive feedback in the climate system (for example by water vapor, high clouds or whatever), you have several options to attack my reasoning"... To be quite specific, and to repeat what both 'e' and I have written on this thread: if the MEP principle is operative, it is part and parcel of the existing climate sensitivities. Straightforward 'black-box' testing of climate sensitivity from paleo evidence, for a variety of forcings, indicates that there is no major negative feedback such as you postulate. You've been avoiding that point of both our replies for some time now. MEP does not magically prevent global warming. -
Berényi Péter at 06:40 AM on 27 October 2010Models are unreliable
#263 e at 05:23 AM on 27 October, 2010 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 The situation is not so nice as you paint it. Sub-grid processes, aerosols and the like are always parametrized in models, that is, these are not derived from first principles, but are chosen to reproduce the past. And as von Neumann said "With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." Computational climate models tend to agree on past trends but diverge considerably in their predictions. It is a sure sign they do use the leeway provided by the parametrization process and use it disparately. -
Tom Dayton at 06:37 AM on 27 October 2010Models are unreliable
mistermack, expanding on e's answer, for more explanation of how observations are used to improve climate models, see the RealClimate "FAQ on Climate Models," in particular the questions "What is the difference between a physics-based model and a statistical model," "Are climate models just a fit to the trend in the global temperature data," and "What is tuning?" -
Bibliovermis at 06:11 AM on 27 October 2010Waste heat vs greenhouse warming
RSVP, You are wrong. No amount of repitition of your misconceptions will make them correct. Please read what has already been posted here again, because you have provided nothing new.
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