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Comments 51 to 100 out of 131:

51. johnd at 20:38 PM on 27 March, 2011
    Gilles at 18:33 PM, "unlikely" unfortunately is something subjective, and we see this in action quite frequently in weather forecasting where different forecasters can use very different models. All too often here in Australia with seasonal to long range outlooks, what one body predicts as most likely will be predicted by another forecaster as most unlikely. It has happened that two totally opposing outlooks have been released by two separate organisations on the same day. Given such differing predictions are not isolated events, "unlikely" therefore cannot be an appropriate means of judging quality.
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52. Alexandre at 20:43 PM on 27 March, 2011
    Gilles and batsvensson How can an event be a test of a climate prediction?
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53. batsvensson at 20:49 PM on 27 March, 2011
    @Alexandra - that's part of the assumption that a theory is based on cause and effect. Do you agree to this?
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54. Gilles at 20:49 PM on 27 March, 2011
    "Back to an “unlikely” event that has been predicted by climate models, if we look at Hansens model from 1988, I repeat what I’ve said on the models are unreliable thread, the global average surface temperature has risen. " the question is : has the rise been unlikely close to Hansen's predictions, or not ? a simple visual inspection of figures concluding that "it matches approximately" is obviously not enough to say that. Alexandre#56 : you cannot always find clear validations of theories. That's unfortunate, but you know, life is not a fairy tale; for instance we don't have yet clear predictions of supersymmetry or worse, brane theories. That's life. The only thing is that before claiming that things are settled and that no doubt is allowed, you need such facts. If you don't have them, you're not allowed - in principle- to make such claims. And the burden of proof is for this who claims he believes in a model - not for this who doubts.
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55. batsvensson at 20:57 PM on 27 March, 2011
    "to qualify a good theory as one which predicts unlikely events is tricky when we look at climate change." Nobody said it will or is easy, but what I think irritates or annoy a lot of people is when pro AGW people goes public and make dead sure "predictions". No such thing can be said to be sure. What we have is likely and unlikely scenarios and these are covered by the error ranges in the models - then of course some stupid journalist must hock onto this and blow things out of proportion with the worst case, which is also the most unlikely scenario, with a "what will happen if we continue as we do" story.
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56. TimTheToolMan at 21:50 PM on 27 March, 2011
    "Weather" in the skeptic's sense doesn't have to be day to day though. "Weather" can mean a few years of ENSO events for example. Since we cant predict whether El Nino or La Nina (or neither for status quo) will become predominant in the future, we cant predict "global" climate either. ENSO is just one of many potential long term changable effects that will determine global average temperatures. Cloud cover is another major one. The view that CO2's effect as a GHG will necessarily dominate over any timescales that we care about is a naive one.
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57. Alexandre at 22:16 PM on 27 March, 2011
    batsvensson #57 Of course I do not agree with that. Theories are based on cause and effect, but that effect is not what is predicted by that theory (allowing for the broader sense of "theory" here). It's like saying "if you can't predict the next 6 you cannot say the dice is loaded". Check the trends, not events. Gilles #58 Who's saying no doubt is allowed? Models are limited approximations of the real world. Any law of physics is a limited approximation of the real world. That is not to say they are useless pieces of fiction. Would you go so far as to say that? Or would you recognize its share of accurate predictions?
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58. johnd at 23:00 PM on 27 March, 2011
    Alexandre at 22:16 PM, checking the trends is fine, but the problem for all models, be they climate or economic, is that ultimately,and always, the trend is your friend until the bend at the end.
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59. Alexandre at 23:23 PM on 27 March, 2011
    johnd #62 The behaviour of a buyer is far more unpredictable than that of a gas. I suggest you get more familiar with what climate models are all about (btw, this could be a suggestion for a future post here at SkS). It's just a calculation with very well established laws of physics. Now, you cannot predict daily weather very accurately, but you can predict its long term average quite well, given the boundary conditions. If you add a greenhouse gas to the atmosphere, you can calculate (and measure) more IR radiation being trapped. You can calculate the temperature difference. You can estimate within uncertainty ranges how water vapor will respond. It's not like trying to guess how the market will behave. You can't say for sure if it will rain on the Amazon on Dec 12th, but you can state quite confidently that December will have far more rain in the Amazon than in the Sahara. Why?
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60. Trueofvoice at 01:55 AM on 28 March, 2011
    Tim, No matter how many ENSOs, or how powerful, in the end they do nothing more than shift the heat around. They do not produce or eliminate it. CO2 dominates climate because it controls the planet's radiative energy balance. The more CO2 we add to the atmosphere, the greater the energy imbalance and the more heat we get. The energy imbalance can be measured and projected into the future as we continue to add GHGs to the atmosphere. This is basic physics.
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61. muoncounter at 02:30 AM on 28 March, 2011
    Gilles #58: "has the rise been unlikely close to Hansen's predictions, or not?" Skip the ambiguity; take these questions to the relevant thread, where there is graphical evidence that your doubts are ill-founded. "you cannot always find clear validations of theories." In this case, theory predicts trend (climate) rather than specific events (weather). Short-sighted individuals who focus on individual events do not look carefully enough to see those trends. Perhaps it is a case of not being able to see the forest for the trees?
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62. Rob Honeycutt at 03:46 AM on 28 March, 2011
    TTTM said... "The view that CO2's effect as a GHG will necessarily dominate over any timescales that we care about is a naive one." That's a very strangely qualified statement. Any timescale that we care about? I believe the point is that we are adding CO2 to the atmosphere at a rate that it is overwhelming the natural radiative balance and causing the planet to warm. I don't believe that is a naive statement in any way.
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63. scaddenp at 06:59 AM on 28 March, 2011
    Tim, repeating earlier comment: "Tell, if you put a large kettle on to hot flame, could you will all the computer modelling in the world accurate predict the convective flow within that pot? Not likely, though you might predict the pattern. (the weather) Could you predict when the kettle will boil? (climate) yes. "
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64. johnd at 08:27 AM on 28 March, 2011
    Trueofvoice at 01:55 AM, if you feel that CO2 dominates the climate, to what lesser degree do you relegate the oceans. The oceans store and move an immense amount of heat energy, apparently more than can even be accounted for. If we are to accept that the "missing" heat needed to balance the equations is somewhere in the oceans, then we must also accept that as long as the ocean currents circulate, that "missing" heat will reveal and perhaps manifest itself causing the currently balanced equations to be rebalanced.
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65. TimTheToolMan at 08:45 AM on 28 March, 2011
    @Trueofvoice "No matter how many ENSOs, or how powerful, in the end they do nothing more than shift the heat around." Thats clearly not the case though is it. During La Nina, global temperatures drop and during El Nino they rise. We measure this and its generally accepted. @scaddenp "Could you predict when the kettle will boil? (climate) yes. " No. Didn't you notice that the pot was much taller than you thought and that heat loss from the sides means that the flame isn't powerful enough to boil the water? There are many very large assumptions about whether climate can be predicted. Dont lose sight of that.
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    Moderator Response: You have managed to start your comment on topic and end it off topic. See "Models are Unreliable."
66. TimTheToolMan at 08:51 AM on 28 March, 2011
    "That's a very strangely qualified statement. Any timescale that we care about?" Would you feel the same if it turned out the majority of observed warming so far was in fact natural and that CO2 was actually expected to increase global temperatures by around 2C after 500 years or more with cuts in emissions that reflected a controlled steady move away from fossil fuels rather than a frantic ill considered one?
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67. Trueofvoice at 09:23 AM on 28 March, 2011
    Tim, During a La Nina heat from the atmosphere is essentially transferred to the oceans. During an El Nino heat is transferred from the oceans to the atmosphere. The heat doesn't go away, it just moves to another part of the planet. Energy only leaves the planet via radiation into space, and this is exactly the process that GHGs interfere with.
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68. scaddenp at 09:25 AM on 28 March, 2011
    Tim, no matter. While you provide a forcing (eg heat from underneath/more CO2 in the atmosphere) then the pot will heat till its temperature enables energy in = energy out. Yes, climate is more complicated because its sensitivity is harder to tie down with the internal feedbacks, but heat it will. Now by what physical process, can you get a sensitivity so low that you manage only 2 degrees per 500 years for realistic emissions? This violates the physics as captured by models, the observed sensitivity for post-1970 temperature rise and constraints from the paleo record? You need some so far unknown negative feedback. Too risky for me.
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69. Gilles at 09:27 AM on 28 March, 2011
    Trueofvoice : so you agree that energy conservation does *not* imply a constant average surface temperature ?
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70. Alexandre at 09:29 AM on 28 March, 2011
    johnd #67 said: if you feel that CO2 dominates the climate, to what lesser degree do you relegate the oceans. Oceans don't have the ability to affect the energy balance of the planet. Surface temperature will be affected by ocean cirulations, but the amount of energy of the climate system will remain approximately the same. The greenhouse effect, OTOH, affects how much energy goes out. And if you attribute the current warming to the oceans, how do answer these questions: - What ocean oscillation became suddenly warmer now then on the last millennium or two? - Why did the outgoing longwave radiation diminish on the last decades? - Why did backradiation become more intense? - Why did IR radiation trapped by GHG have no effect on temperature this time?
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71. johnd at 09:34 AM on 28 March, 2011
    Alexandre at 23:23 PM, perhaps you should read the paper "Impact of Global Ocean Surface Warming on Seasonal-to-Interannual Climate Prediction" that I linked in an earlier post in this thread "johnd at 06:49 AM on 27 March, 2011". It might assist your own understanding of climate modeling. Incidentally, I think the behavior of buyers, and sellers, is extremely predictable, as reflected by the ability of some of the more astute investors of the world to always be ahead of the market. Whilst the study focuses on the time scales the title indicates, what those who conducted the study allow us to appreciate is that as our awareness of all the factors involved increases, the uncertainty widens. Here is an excerpt:- "Based on atmospheric model simulations with historical sea surface temperature (SST) forcing only, Compo and Sardeshmukh (2009) have found that most of the land warming in recent decades is caused by SST rise rather than by its local response to increasing GHG forcing. We note that the SST warming itself may be driven by both the increasing GHGs forcing and slowly-varying natural processes (Solomon et al. 2007). The SST change was found to play a dominant role in determining the land/ocean warming contrast probably via complex hydrodynamic-radiative teleconnections (Joshi et al. 2008; Compo and Sardeshmukh 2009; Dong et al. 2009)."
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72. scaddenp at 09:38 AM on 28 March, 2011
    "Trueofvoice : so you agree that energy conservation does *not* imply a constant average surface temperature ? " It DOES imply zero trend in temperature over long period.
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73. johnd at 09:40 AM on 28 March, 2011
    Trueofvoice at 09:23 AM, you don't feel that the oceans also interfere in that, when they remove heat from the atmosphere, that heat cannot be liberated to space, fast or slowly, and only when the oceans do release heat can that heat then be liberated to space?
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74. TimTheToolMan at 09:43 AM on 28 March, 2011
    "During a La Nina heat from the atmosphere is essentially transferred to the oceans." No. Quite apart from the fact the atmosphere doesn't heat the oceans to any appreciable extent at all, this is a fundamental misunderstanding many people have with regards the energy flows around the earth. Your view comes across as if the sun dribbles energy to the earth which mostly holds it and lets some go to keep in balance and it lets less go with additional CO2 keeping it here. The fact is that the energy flow through the earth is MASSIVE. Three times per day the earth receives and then radiates away the same amount of energy it has accumulated over the last 100+ years.
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75. Trueofvoice at 10:00 AM on 28 March, 2011
    Tim, During La Niña, the easterly trade winds strengthen and cold upwelling along the equator and the West coast of South America intensifies. Sea-surface temperatures along the equator can fall as much as 7 degrees F below normal. We also see that in certain parts of the world such as North America average atmospheric temperatures fall. How does this happen? Since cold is in fact the absence of heat (meaning you can't "add" cold to the atmosphere) atmospheric heat is drawn into the cold water upwelling from the ocean. No, the sun doesn't dribble energy at the planet, it radiates it. Greenhouse gases in the atmosphere trap a certain amount of that radiation, causing a radiative imbalance (temporarily more coming in than going out). The planet responds by heating up, thus radiating more energy and eventually achieving a new radiative balance. Yes the amount of energy entering and leaving the planet is enormous. Increasing CO2 traps a relatively small amount of energy that would otherwise have been radiated back into space, but that energy accumulates over years and decades and eventually begins to impact the greater climate.
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76. Alexandre at 10:10 AM on 28 March, 2011
    johnd #74 The link did not work. I'll try again later, it does not seem to be broken at its origin. But in light of it, and assuming that you read and understood it, how would you answer those questions I asked in my previous post (#73)?
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77. johnd at 10:23 AM on 28 March, 2011
    Alexandre at 10:10 AM, it may take time to download, otherwise do a Google search for the title. This study may not answer the questions you have asked, but it may cause you to rethink what questions need to be addressed.
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78. TimTheToolMan at 10:27 AM on 28 March, 2011
    "How does this happen? Since cold is in fact the absence of heat (meaning you can't "add" cold to the atmosphere) atmospheric heat is drawn into the cold water upwelling from the ocean." No. Atmospheric heat doesn't get "drawn" into the cold water at all. The energy from the earth system is ultimately just gone. Radiated away. The cold water effects the weather with whatever effects that come along with it...Stuff like reduced atmospheric water vapour content is likely, cloud coverage changes, pressure changes cause blockings to change and so on. The cold water is eventually warmed again by downward shortwave radiation (ie direct from the sun) and the quasi-periodic cycle starts again.
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79. Trueofvoice at 10:41 AM on 28 March, 2011
    Tim, Let's say we have an empty olypmic sized (because I always demand the best) interior swimming pool. The air temperature in the building is at 22C. We then quickly fill the pool with water at a temperature of 5C. I guarantee you the air temperature will drop as the cold water absorbs ambient heat from the air in the building. That's how the temperature in a water-cooled engine is maintained. The liquid is kept at a lower temperature so it can absorb heat from the engine and prevent it from overheating.
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80. TimTheToolMan at 11:07 AM on 28 March, 2011
    " I guarantee you the air temperature will drop as the cold water absorbs ambient heat from the air in the building." Of course it will and its through effects like decreased water vapour content and net radiation flow. The water vapour will condense out into the pool taking its heat with it and the difference in radiation means that the net radiation now flows towards the water and away from the atmosphere. But does that heat the pool? No, only to a very tiny extent...the energy simply isn't "sloshed around" in the system as you'd like to believe. Once it leaves the ocean, its going to be radiated away and doesnt wait around until the next La Nina to be put back.
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81. Alexandre at 11:22 AM on 28 March, 2011
    johnd #80 Now I managed to download it. Very interesting, indeed. The importance of better skill on interannual and interdecadal predictability has been stressed on the last WCC, and this Japanese paper seems to address it. Their model seem to suggest a good part of this recent warming may be due to SST, but they also say this quantification is outside the scope of the paper, and that SST itself may have risen because of the GHE. I read only abstract and conclusions. Those questions I asked still stand. If one wants to explain GW via SST rise, he will have to reconcile that with the rest of the existing evidence. The energy trapped by GHG (and the temperature rise caused by it) is well understood and directly measured. I assume you understood the relevance of the questions I asked. PS: this paper was based on a model simulation. It does not seem to have bothered you this time.
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82. KR at 11:31 AM on 28 March, 2011
    TimTheToolMan - "The water vapour will condense out into the pool taking its heat with it..." Actually, the water vapor will stay water vapor until it cools, at which point it will condense. On the larger scale of this example and ENSO cycles - it takes on the order of decades for even moderately transient climate feedbacks to kick in. And even without them, short term (decadal or less) redistributions of energy and temperature variations that inhibit or enhance SAT and thus radiation to space do not change the average radiation capability, or the average absorption, and hence do not change the long term temperature average. The climate will still tend to a stable point, unless there are long term changes such as greenhouse gases that affect climate averages.
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83. IanC at 11:48 AM on 28 March, 2011
    Tim, You said, "Stuff like reduced atmospheric water vapour content is likely, cloud coverage changes, pressure changes cause blockings to change and so on." What causes these to happen in the first place? What causes the water to condense out? To illustrate that the air will cool irregardless of water vapour, what if it is pure nitrogen of 22C over a 5C pool?
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84. TimTheToolMan at 11:52 AM on 28 March, 2011
    "Actually, the water vapor will stay water vapor until it cools, at which point it will condense. " You're talking about rain. That wont happen in the case of a pool in a room. condensation happens on surfaces in this case. "short term (decadal or less) redistributions of energy and temperature variations that inhibit or enhance SAT and thus radiation to space do not change the average radiation capability, or the average absorption, and hence do not change the long term temperature average." So you say. But you have no evidence that say for example La Nina effects wont predominate in the future thus cancelling out any further temperature increases from CO2. It could go the other way and that El Nino effects predominate and radically increase the temperatures. The current assumption is that the status quo happens. Thats a big assumption and is a necessary one if we're to believe we can "predict" climate in the future. And if you want to look at effects that actually effect the irradiance and radiation then clouds will do that and again we just dont know what they'll do in the future under altered climatic conditions.
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85. scaddenp at 11:52 AM on 28 March, 2011
    Tim, are you denying that the ocean's are accumulating heat despite the OHC data? You are aware that there is a TOA energy imbalance?
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86. TimTheToolMan at 12:01 PM on 28 March, 2011
    "Tim, are you denying that the ocean's are accumulating heat despite the OHC data" Where did that crazy jump in logic come from? "You are aware that there is a TOA energy imbalance?" Were you aware that what we measure and what we calculate it should be are radically different?
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87. TimTheToolMan at 12:07 PM on 28 March, 2011
    And to the mods, this discussion isn't supposed to be about models. This is about the difference between day to day weather and effects that are longer that have considerable effect on the earth's energy balance (like ENSO) that cant be predicted in the same way we cant predict day to day weather.
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88. scaddenp at 12:30 PM on 28 March, 2011
    Great that is settled that oceans are heating. For a moment, I thought you were arguing that there was none. Given ENSO doesnt seem to show much on the 0-2000m OHC, how come you think it has considerable influence on the long term energy balance? This isn't rhetoric - I am not following your argument. And yes, TOA imbalance size has issues with absolute accuracy of the measurement, (but not the sign).
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89. johnd at 12:35 PM on 28 March, 2011
    Alexandre at 11:22 AM, I haven't time to get into deep discussion right now, but regarding your PS, it hasn't bothered me because that is what the paper is generally about. Examining the uncertainties and limitations of our current far from complete understanding, and how those limitations has a substantial impact on the global climate predictability. Whilst is does produce some useful and interesting modeling, that is a useful byproduct rather than the objective of the study, but enough to support relevant points one might want to debate. One aspect I found particularly interesting is the noting of the JAMSTEC prediction system being superior in certain areas to many other existing systems, JAMSTEC being one tool that I have frequently referred to for a number of years now.
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90. TimTheToolMan at 12:42 PM on 28 March, 2011
    "Given ENSO doesnt seem to show much on the 0-2000m OHC," I'm not convinced we have a good enough handle on OHC yet. Since Argo there has been no ocean heating. Its pretty clear that the stitching together of the two datasets (XBT et al + Argo) has created an unrealistic jump in OHC that is attempting to be resolved even now. Its another one of these cases where ( -SNIP: accusation of fraud deleted- ) change was thought to be happening quickly and the more we measure it, the less it changes.
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    Moderator Response: [DB] In deference to scaddenp, who has already replied to this, your comment was snipped instead of deleted. Future comments with similar accusations (and even insinuations) of fraud will be deleted; be advised.
91. TimTheToolMan at 12:54 PM on 28 March, 2011
    "Given ENSO doesnt seem to show much on the 0-2000m OHC" Oh yeah, and I generally disagree with your assessment anyway. So does NOAA http://www.pmel.noaa.gov/tao/elnino/wwv/ "El Niño/Southern Oscillation (ENSO) variability is intimately linked to alternating stages of oceanic heat content build-up and discharge in the equatorial Pacific (Wyrtki, 1985; Cane et al, 1986; Zebiak, 1989). Jin (1997) elegantly described the relationships between heat content, sea surface temperature and zonal wind stress in his "Recharge Oscillator" theory of ENSO. Recent studies of oceanic and atmospheric variability have confirmed these relationships and elaborated on their implications for understanding the dynamics of the ENSO cycle (Meinen and McPhaden, 2000; Kessler, 2002; Trenberth et al, 2002). "
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92. scaddenp at 13:05 PM on 28 March, 2011
    Okay, but you will be convinced if 10 years down the track, the OHC from argo does fit the expected response from modelling? Also, we have a few cycles of ENSO since argo - agreed it seems to have little influence on 0-2000 OHC? Which I would read as little influence on long term energy budget.
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93. scaddenp at 13:08 PM on 28 March, 2011
    Missed your post. I entirely agree about upper ocean OHC. ENSO has major role in heat cycling. But I am talking about total OHC as indicator of global energy budget and 0-2000 (best proxy for it) looks smooth to me.
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94. scaddenp at 13:12 PM on 28 March, 2011
    Just to be clearer. I am postulating that ENSO is simple internal variability in the system and does not impact on long term energy budget, for which total OHC is a better indicator.
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95. TimTheToolMan at 13:21 PM on 28 March, 2011
    "the OHC from argo does fit the expected response from modelling?" Expected response from modelling? It may surprise you that there is no expected response from modelling since 2003. I'm sure there is actually but I'm equally sure it will only be brought out by the likes of Gavin if OHC does increase again. http://www.realclimate.org/index.php/archives/2011/01/2010-updates-to-model-data-comparisons/#more-6056 "The next figure is the comparison of the ocean heat content (OHC) changes in the models compared to the latest data from NODC. As before, I don’t have the post-2003 model output, but the comparison between the 3-monthly data (to the end of Sep) and annual data versus the model output is still useful." No it isn't Gavin. Not when actual figures from models can be determined but noone has seen fit to do so for the last 8 years or put another way, since the OHC stopped increasing ...very much not in line with the model outputs... "Okay, but you will be convinced if 10 years down the track, the OHC from argo does fit the expected response from modelling?" I will look at the data as it appears and make my assessment then. Would you be giving up your beliefs in AGW if there is no OHC increase over the next 10 years?
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96. TimTheToolMan at 13:23 PM on 28 March, 2011
    "Just to be clearer. I am postulating that ENSO is simple internal variability in the system and does not impact on long term energy budget, for which total OHC is a better indicator. " Just to be clearer, I'm pointing out that you have no evidence for this and our ability to predict climate into the future relies on it.
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97. IanC at 13:31 PM on 28 March, 2011
    Tim, Scaddenp, Given that ENSO is due to a redistribution of warm and cold water across the pacific, there is no reason I think to believe that the overall heat content will increase or decrease significantly. Furthermore, the main action occurs above the thermocline, which is about 100-200m or 10% of the 0-2000m layer. Since the thermocline anomaly is also restricted to the equatorial pacific, I will be surprised if you can see ENSO signal in the OHC.
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98. TimTheToolMan at 13:36 PM on 28 March, 2011
    "Given that ENSO is due to a redistribution of warm and cold water across the pacific, there is no reason I think to believe that the overall heat content will increase or decrease significantly." I guess you missed the post. There is every reason to believe ENSO decreases OHC http://www.pmel.noaa.gov/tao/elnino/wwv/
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99. scaddenp at 13:46 PM on 28 March, 2011
    "I will look at the data as it appears and make my assessment then. Would you be giving up your beliefs in AGW if there is no OHC increase over the next 10 years? " Obviously - and same for more many other predictions of climate models if they don't turn out either. You neglected to tell us about Gavin's response was to when OHC would be available and tried oblique accusation of hiding data instead. Hmm. I'll believe that if there is no OHC model result in AR5. IanC - Lyman 2010 0-700m total OHC certainly looks to have ENSO signal in it to me, though I would be first to admit that I know little enough about oceanography.
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100. TimTheToolMan at 13:51 PM on 28 March, 2011
     " I'll believe that if there is no OHC model result in AR5. " They'll have to have it by then, its a vitally important measure of our CO2's effect in our climate and needs to be compared to the models. But apparently not so vital that it cant be "ignored" for 8 years...
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