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Comments 118551 to 118600:

118551. chris at 05:55 AM on 1 June 2010
        Working out climate sensitivity from satellite measurements
        shawnhet at 05:08 AM on 1 June, 2010 In fact Spencer and Braswell don't really understand the "linear striations" (as I've pointed out umpteen times now); e.g. they state:

        "Although these feedback parameter estimates are all similar in magnitude, even if they do represent feedback operating on intraseasonal to interannual time scales it is not obvious how they relate to long-term climate sensitivity."

        and

        "Since feedback is traditionally referenced to surface temperature, extra caution must therefore be taken in the physical interpretation of any regression relationships that TOA radiative fluxes have to surface temperature variations."

        and:

        "It is clear that the accurate diagnosis of short-term feedbacks – let alone long-term climate sensitivity -- from observations of natural fluctuations in the climate system is far from a solved problem."

        You disagree strongly withe S&B and apparently feel sure that you know what the "striations" mean even if S&B don't. You're certain that they can be related to climate sensitivity in the commonly accepted understanding of the term (equilibrium surface temperature response to radiative forcing), when S&B explicitly caution against that extrapolation. Fair enough, but I don't find your assertions very convincing. Still, we can, if we want, make a preliminary assumption that the striations relate to a feedback parameter [f(s)]. If we do so, and parameterize a realistic climate heat capacity model with S&B's estimate of a possible f(s), we find (see my post just above), that the value of the climate sensitivity is rather little influenced by f(s). Since Lin et al (2010) [see citation in my posts above] have published this analysis, why not just look at their paper shawnet?
118552. Riccardo at 05:48 AM on 1 June 2010
        There's no empirical evidence
        PaulK, Schwartz is the same as mine, you wrote it wrong. But anyways, if we agree that H indicates a variation and that your f(t) (apart from the sign convention) includes the forcing and the radiative thermal emission, we have an agreed starting point. You may not want to linearize the radiative thermal emission and write it as εσ(T^4-Te^4) throughout, but in this way you make the solution considerably harder to find. Afterall next term in the expansion is of the order of 10^-4, i'd say it's negligible.
118553. shawnhet at 05:31 AM on 1 June 2010
        Working out climate sensitivity from satellite measurements
        Sorry, in the above expression fs should vary btw -3.3W/m2 (the non-existant feedback) and -6W/m2 under S&B. Plugging in 0 for fs will give the wrong answer. Cheers, :)
118554. shawnhet at 05:08 AM on 1 June 2010
        Working out climate sensitivity from satellite measurements
        "Nope. You're saying stuff that simply isn't true shawnet." Frankly, this is tiresome. You, by your own admission, did not understand the central point(the linear striations) of the S&B paper, but you have been pontificating about it as though you are an expert. Since you like Lin's framework, I will show you how it works using that system. T (t→ ∞) = −F(t→ ∞)/(fs + fm)....Lin et al (2010) cited in a post above. Using, the above formula *hold everything constant except fs*, now vary fs. Start by assuming that it is nonexistant(ie 0) and then calculate what the value of T (t→ ∞) is when you change the value of fs to the value assumed by SPencer & Braswell. After doing that, then re-read my posts here. If you can do that and have further issues with *what I've written* I'll try and address them. Please refer to the answers you've gotten for T, as there is no point continuing this until I'm sure that you get the math.
118555. ubrew12 at 05:00 AM on 1 June 2010
        Could global brightening be causing global warming?
        Figure 1 is solar at the surface. The text describes how some of this increased solar at the surface is due to reduced absorbed solar in the atmosphere (soot), and just moving the point of absorption from the atmosphere to the surface doesn't constitute 'global warming'. Also, some of this increased solar at the surface is due to a mechanism (clouds) that also increases the amount of infrared radiation leaving the earth. That is, the same mechanism cools as well as heats. Its the net effect, not merely the surface solar effect, that we should be measuring. Bottom line, just looking at the surface solar absorption is incomplete. Its cherry picking, which is probably why Monckton is doing it. Monckton is asking his listeners to, in effect, calculate the water level in a wooden tub by only considering the rate of water entering the tub, and ignoring the various holes in the tubs bottom.
118556. Vinny Burgoo at 04:23 AM on 1 June 2010
        Why Greenland's ice loss matters
        Peter Hogarth, the Stone 2010 study doesn't show that 'we now probably have a more realistic model' It comes close to implying that but let's wait until it's finished passing through the peer-review process. I mentioned the other issues here on SS. (JC, to his credit, swiftly removed the links.)
118557. Tom Dayton at 04:19 AM on 1 June 2010
        Empirical evidence that humans are causing global warming
        Poptech, Following up on Riccardo's reply, you need to realize that a model is inherent in even an old-fashioned liquid-filled thermometer that is a glass tube attached to a wooden board on which are painted numbers. The numbers are the model.
118558. Vinny Burgoo at 04:16 AM on 1 June 2010
        Why Greenland's ice loss matters
        Riccardo, an accurate paraphrase can be misrepresentation if essential context is left out. Is this what our host did? Here's his paragraph in full: Climate modelling of the Greenland ice sheet predicts eventual collapse of the Greenland ice sheet if CO2 levels go over 400 parts per million (ppm). We're currently at 392 ppm. At 400 ppm, they predict that over the next 400 years, the ice sheet will lose between 20 to 41% of its volume (Stone 2010). This is equivalent to roughly 1.4 to 2.8 metres of sea level rise just from Greenland. Three things. (1) JC used Stone 2010 to collapse 'eventual' to '400 years'.(Does anyone know who 'they' are?) Why? (2) Stone 2010 is still in the middle of the peer-review process, so what's it doing on a website that makes such a big deal out of peer-review? (3) The Stone 2010 findings about volume-loss weren't predictions. They came from low-resolution tests of the performance of models that had been re-tuned to make them work with more up-to-date data.
118559. GFW at 04:13 AM on 1 June 2010
        Could global brightening be causing global warming?
        Now that four people :-) have combined for a thoughough answer to RSVP, let's think about Alexandre's question. Ah, I see part of the answer. Figure 1 shows the combined effect of (apparently mostly aerosol) changes to incoming shortwave at the Surface. Figure 2 shows how each component affects the total (incoming & outgoing, all wavelengths) radiation budget at the Top-of-Atmosphere. So they aren't directly comparable. Nonetheless, Alexandre has a point because I don't see in figure 2 evidence for an actual *decline* in aerosols that would explain figure 1. Anyone?
118560. chris at 04:03 AM on 1 June 2010
        Working out climate sensitivity from satellite measurements
        shawnhet at 02:29 AM on 1 June, 2010 Nope. You're saying stuff that simply isn't true shawnet. It's very difficult to escape the interpretations from Spencer & Braswell's own words that their "linear striations" have no necessary relationship to climate sensitivity (enhanced earth temperature in response to radiative forcing). So their analysis has nothing whatsoever necessarily to do with climate sensitivity. It’s tedious to keep saying this, and I wish you would hunker down and read their paper before insisting on interpretations that S&B patently don't make. The equation you present "T3=T1*SF*LF" (what are "SF" and "LF"?) doesn't make any sense in the context of S&B's analysis. Even 'though S&B are not sure of the physical basis or significance of their "linear striations", we can make a model of the real world response to radiative forcing making the preliminary assumption that they (the "striations" relate to a fast response to forcing [f(s)]. An appropriate equation to estimate the temperature change arising from radiative forcing, incorporating both a fast feedback [f(s)] and a feedback term in recognition that the real climate system has an "inertia" or "memory" [f(m)] is of the form: T (t→ ∞) = −F(t→ ∞)/(fs + fm)....Lin et al (2010) cited in a post above. In this case realistic values of f(m) indicate that the climate sensitivity has rather little dependence on f(s). Lin et al show this directly, and state:

        "Changes in f(s) values directly affect our solutions of fm, but the effect of different fs values on total feedback coefficient ftot is small because the temperature and net radiation constraints force the modeled climate system to generate similar amounts of net heat and temperature increases to satisfy these boundary conditions. Thus, the basic conclusions about climate feedback and sensitivity would not be affected much by the choice of fs."

        So even if S&B's "striations" relate to a fast feedback parameter (we don't know), and whether or not these "striations" have any relation to climate sensitivity (S&B say they don't necessarily have any), and even if we nevertheless model the climate response to forcing making the preliminary assumptionthat they can be used to parameterize a fast feedback [f(s)] , the effect on calculated climate sensitivities is small. And remember that the real world makes sense, shawnhet. Just as you can't simply invent equations out of thin air, nor can you invent phenomena out of thin air. You can't obtain a "perfectly sensible explanation of the real world", by inventing a non-existent ocean cycle effect (eg PDO) that magically creates thermal energy. If the PDO (or other "ocean cycle effects") are ocean cycle effects then they can't possibly contribute to secular surface temperature trends (persistent temperature rise) since they are cycles. We don’t have to “guess” at this, or pretend that we don’t know what we do know (“year zero science”!). These issues have been studied at great length. A recent study indicates for example that “ocean cycles” have made essentially zero contribution to the warming of the last 100-odd years. So like your equation, your "sensible explanation of the world" is simply incompatible with what we know of the real world.
118561. Riccardo at 03:22 AM on 1 June 2010
        Empirical evidence that humans are causing global warming
        Poptech, I'm sure you don't realise the consequence of what you said. I can not immagine any measurements without a model, a simulation, some data analysis but the simplest ones. No modern experimental apparatus, no high tech gadget can be immagined without models and simulations of some sort. But maybe you don't know, if you shout the alarm in bold characters for a trivial background subtraction. It looks like you think that it's enough to push a button and magically the "measurements" come out. The age of Galileo and Newton is over, get real.
118562. Peter Hogarth at 03:10 AM on 1 June 2010
        Why Greenland's ice loss matters
        Vinny Burgoo at 00:27 AM on 1 June, 2010 Stone 2010 updates the boundary conditions for modeling changes in Greenlands ice sheet with more realistic input data. Specifically bedrock and ice thickness, temperature and precipitation. They use as many recent real observations as possible. In doing so they discover that the modeling run steady state with the new boundary conditions overestimates the current amount of ice by 25% compared with actual observations. Re-tuning the model to obtain more realistic current ice levels and then projecting forwards in time under the 400ppm CO2 scenario, the revised model suggests greatly increased ice loss under all 5 parameter sets compared with the previous unadjusted model, which had “predicted” similar future ice volumes to today at 400ppm. In other words our previous best predictions (or model outputs if you wish to be pedantic) underestimated future ice loss under given conditions, and we now probably have a more realistic model. I’m not sure John has really used this paper out of context, but I’m guessing he’ll comment. If you have other specific cases of misrepresentation, it would be useful to point these out so that amendments can be made if needed. I certainly don’t mind being corrected if it is shown I’ve misunderstood something, and this is probable if I stray from my areas of expertise. I would also hope you adhere to the same critical standards when visiting other sites!
118563. Riccardo at 02:38 AM on 1 June 2010
        Why Greenland's ice loss matters
        "Although not completely collapsed, the 400p pmv ice-sheets for Figure 12b-e are somewhat reduced in the north of the island, with a reduction in ice volume compared with the modern day ice-sheet volume ranging between 20 to 41%. However, the scenario in Fig. 12f shows almost complete collapse at 400 ppmv with a reduction in ice volume of 81%." this is what the paper says. It's self evident that there's no misinterpretation whatsoever. I find only one (irrelevant) inaccuracy in what John wrote, it's not in 400 hundred years. The paper says that the results shown are after 400 hundred years of model integration, which is not the same thing as 400 years from now. As for the referee's comment, you're largely off target. Stones as well as John here did not make any projection of our future, as the referee advised. Both described what happens in a 400 ppmv world and none of them "predicted" a real world with a constant CO2 concentration at 400 ppmv for centuries. You may not like John's wording but the meaning is straightforward. Although not relevant in this particular case, i agree that research papers are often treated very badly around in the blogsphere.
118564. Alexandre at 02:38 AM on 1 June 2010
        Could global brightening be causing global warming?
        I did not follow the point. Shouldn't the increase shown in Figure 1 somehow appear in the aerosol lines of Figure 2? Where did I understand it wrong?
118565. shawnhet at 02:29 AM on 1 June 2010
        Working out climate sensitivity from satellite measurements
        "ONE: Your first point is confused isn’t it? One the one hand you say: ”S&B (and I)are not talking about the long-term feedback response (ie climate sensitivity),…” ...which we can all agree with, since that’s obvious by reading the paper and Spencer and Braswell (S&B) state this explicitly. But then you say: ”However, for a given set of long-term feedbacks S&B predict a less sensitive climate than if short term variations are governed by noise(in S&B's terms).” Respectfully, Chris, it is you who is confused. Let's say we have a forcing that instantly raises the temperature(T1) by 1C. Under S&B, that instant feedback is then acted on by a feedback(SF) that drops the temperature by 0.5C(T2), finally T2 is acted on by a series of long-term feedacks(LF) that multiply it by 3 ie T3=T1*SF*LF. Think about it. If SF is <1, then T3 *must be* less than if SF=1 *where everything else is equal*. Hopefully, now, you can understand where S&B are coming from. " The real world makes sense. In much the same way that a paper can’t at the same time be about climate sensitivity and not be about climate sensitivity, so the climate sensitivity (let’s say the Charney climate sensitivity) can’t be both significant and insignificant at the same time. The earth’s climate as it stands now does respond to enhanced radiative forcing with a surface temperature that rises to a new equilibrium compatible with this forcing. This sensitivity cannot at the same time be very small (~0.5 oC of warming for a radiative forcing equivalent to 2xCO2) and considerably larger (~2-4.5 oC of warming for 2xCO2)." Just FYI, now that you hopefully understand what S&B are saying, there is no contradiction btw assuming a short-term feedback of 0.5C to CO2 forcing, which is **then** multiplied by 2-4.5 by long-term feedback effects. If you combine such a framework with an ocean cycle effect(eg PDO), you have a perfectly sensible explanation of the real world. Cheers, :)
118566. Alden Griffith at 02:12 AM on 1 June 2010
        Could global brightening be causing global warming?
        Here's my analogy of Monckton's logic: We can think of Monckton's attempt to calculate climate sensitivity from Pinker's 1983-2001 data (http://www.youtube.com/watch?v=og_Bu2zO61g&feature=related) as similar to trying to calculate an automobile's average speed over an entire trip. The problems are that (1) Monckton is estimating the average speed only from the tiny amount of time in which the car actually passes him by (the 1983-2001 period) instead of looking at a longer portion of the trip, and (2) he is forgetting that he too is also in a moving car (not including other opposing radiative effects of clouds and aerosols)! So how much can you say about the average speed of a car from point A to point B by watching it briefly pass you by and forgetting that you are also moving too? Zippity Dooda! Nothing! As Tamino so nicely put it, "if you can't convince them with logic, dazzle them with BS."
118567. Jim Eager at 02:04 AM on 1 June 2010
        Could global brightening be causing global warming?
        Think CO2e, RSVP. CH4 has gone up by 150%, N2O by 15%. CFCs and other purely engineered chemicals did not even exist.
118568. Sean A at 01:57 AM on 1 June 2010
        On temperature and CO2 in the past
        Gallopingcamel, are you saying that CO2 doesn't cause warming? You may want to check out a few of the other pieces of the puzzle, for example some recent posts here. Over these timescales, warming increases CO2 which causes more warming: The significance of the CO2 lag Has the greenhouse effect been falsified?
118569. Vinny Burgoo at 00:27 AM on 1 June 2010
        Why Greenland's ice loss matters
        JC: At 400 ppm, they predict that over the next 400 years, the ice sheet will lose between 20 to 41% of its volume (Stone 2010). Stone 2010 doesn't predict anything. It is an investigation of current deficiencies in ice-mass modelling, not a crystal ball. Referee Comment C194 puts this better than I could: You don’t draw any direct conclusions about the future of the Greenland Ice Sheet from your modelling, and I think this is important not to do that. The conclusion of your work should relate to the model and not to the Greenland Ice Sheet. You have shown that the model is very sensitive to parameters, and hence any conclusions drawn from it about the future of the ice sheet itself should be seen in the light of this sensitivity and the model deficiencies. Otherwise it would be easy for someone to take Fig. 12f, in particular, out of context, to show that Greenland may not exist in a 400ppmv world. You weren't quite that bad. You took Fig. 12e out of context (41% versus 81% loss). Bad enough, though - and, in my experience, entirely typical of how research papers are treated around here. I think this is the fifth misrepresented paper I've found at Skeptical Science. I don't visit very often and I click on very few of your linked references, so five is a worryingly high number, especially as Skeptical Science is widely promoted as a source of balanced and authoritative information. In my experience, it isn't.
        Response: Vinny, I try to be balanced and accurate in how I represent papers but I've never said I'm infallible. But if I do make errors, I always correct them, I publicly admit my errors as I have done in the past with you and endeavour to not repeat the error. My primary goal is to further an understanding of climate by communicating the full body of evidence - misrepresenting the science is the last thing I want to do.
        
        In this case, I think it's a reach to say Stone 2010 is just about modelling therefore its inappropriate to talk about the model results. While there is still much work to be done on modelling the Greenland ice sheet, does that mean we're not allowed to talk about the model results until they're perfect? In any case, I'm attempting to represent the paper as written, not the comments of that referree's comment. I will point out also that I chose to describe their best case scenario, not the worst case - a bit of IPCC-like conservatism on my part.
        
        But the broader point here is that the Stone 2010 paper is just one result among many. There is also an empirical result (the paleoclimate study on over 6 metres sea level rise in the last interglacial), a semi-empirical result (mapping sea level rise to temperature to predict 75cm to 180cm by 2100. There's an alternative method of modelling glacier dynamics that finds sea level rise of 80 cm to 2 metres by 2100. These papers all use independent methods to arrive at the same conclusion - that Greenland is highly sensitive to sustained warmer temperatures and we can expect it to contribute significant sea level rise over this century and beyond.
        
        So while I appreciate your feedback about Stone 2010 - especially the fact that it has yet to be approved of which I wasn't aware of - can I suggest you don't lose sight of the bigger picture and that you survey the full body of evidence before coming to any conclusions of where Greenland is headed.
        
118570. Daved Green at 23:34 PM on 31 May 2010
        Latest GRACE data on Greenland ice mass
        wes george@18 I saw a Documentary on people living in siberia where to bury their dead they melted the permafrost with fire so they could dig a hole , they had to take turns working outside of 15 mins becuase it was so cold , maybe this is what the vikings did ?
118571. Arkadiusz Semczyszak at 23:23 PM on 31 May 2010
        On temperature and CO2 in the past
        How can we be wrong about the valuation feedback, I again recommend: Interglacials, milankovitch cycles, and carbon dioxide, (Marsh, 2010)
118572. Arkadiusz Semczyszak at 23:20 PM on 31 May 2010
        On temperature and CO2 in the past
        "In particular, during the warm periods the climate sensitivity is higher than average. In other words, the temperature increase produced by a forcing is higher when the system is in its warm phases." This assertion seems to be contrary to the basics of Eco-cybernetics. If we treat the Earth as a global Ekosfera complex system - with specific boundary conditions, the addition of energy to stabilize it. It is "richer" in energy - "can afford" to run, to strengthen the equivalent feedback - the more stable equilibrium. Yes because of the slowness of action of some feedback, greater stability of the system warm can be seen only over longer periods of time. For example, biocenosis "warm" are more biodiversity, which stabilizes ecosystems (generalizing - The diversity-stability debate, McCann, 2000). In this way, they (the biocenosis - ecosystems), one of the elements stabilizing the climate. "In the previous interglacial (the Eemian), there was a huge overlap between temperature increase and CO2 increase, which makes it near impossible to know the two-way influences. ..." "... professor Jianli Chen of the University of Texas also found that in a previous inter-glacial period called the Eemian, global temperatures were 6C higher than today, with CO2 levels roughly the same." ... the same - why?
118573. Ken Lambert at 22:58 PM on 31 May 2010
        Robust warming of the global upper ocean
        kdkd #69 Is 16 years of "Robust" global upper ocean warming - which is the subject of this blog; regarded as climate or weather kdkd? If it is climate, then BP and I have illustrated that the large jumps in OHC before 2004 are calibration offsets of the XBT-Argo transition, and most probably illusory. If it is weather 'noise' then the same conclusion applies - not 'robust' but illusory.
118574. heather stevens at 22:52 PM on 31 May 2010
        How you can support Skeptical Science
        thank you thank you thank you for existing! This site is fantastic. I have enough sense to know that global warming is occurring, but not the technical knowledge to often back up a discussion with a climate change denier. Thanks to this site i'm now armed with a bit more techy detail and will refer my family and friends who are unsure about GW to this site. thank you! heather Assessing the Risk from Sea Level Rise - Climate Change Impact Assessments
118575. chris at 22:31 PM on 31 May 2010
        Working out climate sensitivity from satellite measurements
        A slightly broader assessment of S&B(2010) “Year zero science” [*]. It’s a little unfortunate to have to consider this, but it’s also sad that the efforts by scientists working in this area are apparently of effectively zero import once a couple of “celebrity crowdpleasers” enter the arena. The studies of Spencer and Braswell (2010) [and Lindzen and Choi (2009)] are two out of dozens of papers that address TOA radiative transfer, and the issue of estimating climate sensitivity from short term radiative response to temperature fluctuations (e.g. see papers cited in John Cook’s top article and here). Outside of proper science forums and quality science blogs (like this one), all of that other work is essentially invisible. Much like Lindzen and Choi (2009), S&B(2010) is already building up a head of blogsphere “steam” and if one looks at the presentations on the subject at a curious climate change politicisation get-together in Chicago a couple of weeks ago, for example, one might think that L&C and S&B is the entire science on this subject! In fact L&C(2009) is the only study that S&B(2010) explicitly refer to as support of one interpretation of their “analysis” [S&B state ” This is similar to the feedbacks diagnosed by Lindzen and Choi [2009] from interannual variability in recently recalibrated Earth Radiation Budget Satellite data…”]. And yet the analysis of Lindzen and Choi (2009) has been shown to be horribly flawed (see top article of this thread). Pretending that the wider science doesn’t exist and that the subject can thus be interpreted in its entirety through a couple of flawed analyses isn’t a good way to understand scientific issues! The real world makes sense. In much the same way that a paper can’t at the same time be about climate sensitivity and not be about climate sensitivity, so the climate sensitivity (let’s say the Charney climate sensitivity) can’t be both significant and insignificant at the same time. The earth’s climate as it stands now does respond to enhanced radiative forcing with a surface temperature that rises to a new equilibrium compatible with this forcing. This sensitivity cannot at the same time be very small (~0.5 oC of warming for a radiative forcing equivalent to 2xCO2) and considerably larger (~2-4.5 oC of warming for 2xCO2). Since (outside of “year zero” “philosophies” of “science”) there is a rather large scientific evidence base that supports the latter climate sensitivity, one needs to provide some strongish evidence if one wants to make headway with scenarios of low climate sensitivity. Likewise if one wishes to pursue very low climate sensitivities, one really needs to explain their fundamental incompatibility with real world observations. After all the rise in atmospheric [CO2] since the mid-late 19th century (290 then to 390 ppm now) is associated with a global temperature rise of 0.8-0.9 oC. We know that the earth’s temperature hasn’t yet risen to the equilibrium temperature compatible with the enhanced greenhouse forcing. We know that atmospheric aerosols have offset some of this warming. And yet within a “year zero” philosophy where everything we know about the real world is thrown out in favour of a cherry-picked selection of data points or wild extrapolation from observations of “linear striations” we are “led” to believe that the huge rise in atmospheric [CO2] has only contributed ~0.15 oC of global warming during the last 150 years. So with all the aerosols we've pumped into the skies the world really should have cooled somewhat during this period, polar, glacier and sea ice should have expanded somewhat, and sea level rise stopped or even started to reverse. Something doesn’t add up…. [*]”Year zero science” could also be termed “clean slate science”, and refers to the “philosophy” whereby a single measurement or analysis is created or selected, and publicised as if it constitutes the essential evidence that bears on a subject while pretending that the wider knowledge base doesn't exist.
118576. chris at 22:10 PM on 31 May 2010
        Working out climate sensitivity from satellite measurements
        shawnhet at 03:55 AM on 30 May, 2010 You haven’t really addressed my points shawnhet, except (incorrectly) point #5. Perhaps I can make my points clearer. It’s also helpful to address this paper in its wider context since (as we both know) while we’re ostensibly addressing a scientific paper, there’s some interesting “non-science” stuff going with this work and how it’s publicised blogospherically! I’m going to do the latter in a second post – that way if the moderators consider that I’m straying from the science or my post induces a series of follow up non-science posts, it (and they) can be deleted. ONE: Your first point is confused isn’t it? One the one hand you say: ”S&B (and I)are not talking about the long-term feedback response (ie climate sensitivity),…” ...which we can all agree with, since that’s obvious by reading the paper and Spencer and Braswell (S&B) state this explicitly. But then you say: ”However, for a given set of long-term feedbacks S&B predict a less sensitive climate than if short term variations are governed by noise(in S&B's terms).” That odd dichotomy (the paper both isn’t and is about climate sensitivity) is a good example of the confusion that can arise from Spencer’s style of “science by insinuation” (where you say one thing in a scientific paper, and something different on a blog?) I can’t think of another reason how you can simultaneously conclude two incompatible things – one certainly can’t arrive at that conclusion from reading S&B’s paper. TWO: Your first point is correct. S&B state that their “linear striations” don’t have anything necessarily to do with climate sensitivity (the equilibrium surface temperature response to radiative forcing). They find some “linear striations” in an analysis of short term TOA radiation/temperature relationships but don’t quite know what they mean, although they consider that they might have a physical basis. That’s fine. The next step, scientifically-speaking, is to establish what these “striations” are and what they really mean (if anything) in relation to TOA radiative transfer. THREE: I’d say that’s where the science stands on S&B(2010). However it’s perfectly acceptable (scientifically-speaking) to make a presumption about what this might mean, and within that model to assess potential consequences. Lin et al (2010) do this in a couple of papers (cited here). They use S&B’s “linear striations” to parameterize a fast feedback parameter [f(s)] of a radiative transfer model and find that if one uses a model that bears some realism to the real world (i.e. one in which there is a non-zero “inertia” or “memory” in the climate system), that S&B’s “linear striations” are entirely compatible with a real world climate sensitivity consistent with the wealth of independent data (Lin et al find a “best” value for the climate sensitivity of 3.1 oC). Your assertion "You'll note that they had to "add" something to make sense of what Spencer found." isn’t correct. They’aren’t “making sense of what Spencer found”. They are taking an interpretation of S&B’s “linear striations” at face value and addressing how this might affect real world climate sensitivity
118577. F. Murdoch at 21:37 PM on 31 May 2010
        Could global brightening be causing global warming?
        @RSVP You cannot compare the increase in forcing to the increase in GHG's. After all, at equilibrium the effective forcing would be 0, regardless of the concentration of GHG's.
118578. PaulK at 20:53 PM on 31 May 2010
        There's no empirical evidence
        Riccardo #98 You wrote: "it's not clear to me what you mean by "the assumptions in your version of the heat balance equation". Which assumptions did "I" make? Did you find something wrong?" I used the term "your version" to be simply descriptive, not pejorative. Strictly we have covered three versions of the heat equation:- Schwartz version:- dH/dt = F * exp(-t/tau) "Your version":- dH/dt = F(t)−λΔT "My version":- dH/dt = -f(t) "Your version" makes the same assumptions that are built into the Schwartz model, and then one additional assumption, which is the curtailment of higher order temperature terms in the exponential expansion (or in the derivative form of S-B apploied to Ts - it comes to the the same thing). I wasn't suggesting that this is "wrong":- each of these versions is founded on its own assumptions. I am claiming that my solution is more general than Schwartz, and hence more general than "your version". Where are we going with this? With real-world data (CO2), over a wide variety of assumptions imposed on "my version", the rise in OLR cannot be reconciled with the IPCC assertions and assumptions. This whole conversation started because, as I stated, the "hand-waving" arguments about CO2 being the primary driver, BUT thermal emissions overwhelm the OLR response don't hold water for the long equilibration times asserted by the IPCC .
118579. Marcus at 20:49 PM on 31 May 2010
        Could global brightening be causing global warming?
        Consider this though HR. Sunspot numbers have been dropping marginally since 1979-so the amount of radiative energy-in W/Square meter, have been dropping over that time period. So for there to have been even a small rise in radiation at the earth's surface means that there must have been a change in Earth's albedo (reduced aerosols, reduced cloud cover etc etc.) However, as John pointed out-all these things also contribute to the retention of IR radiation as it heads out to the upper atmosphere. So a reduction in clouds & aerosols should-if I understand it correctly-have little effect on the *net* radiation balance-because they mostly offset each-other. The fact that the amount of IR radiation detected in the stratosphere has dropped-in *spite* of the reduction in heat retaining clouds & aerosols gives even greater credence to the idea that it must be increasing GHG emissions which are trapping the heat in the lower atmosphere. Now, I accept that I could have the total wrong end of the stick, but it makes sense to me. What say you, John?
118580. Marcus at 20:43 PM on 31 May 2010
        Could global brightening be causing global warming?
        Either way, Ed Davies, what RSVP hasn't factored in is that we're *not* just talking about CO2-it represents *all* GHG emissions-& CH4 is a more potent GHG gas, & has risen at a sharper rate than CO2. It could also explain why it leveled off modestly around 1980-the leveling off of methane emissions (but they've started to climb again!)
118581. Ed Davies at 19:33 PM on 31 May 2010
        Could global brightening be causing global warming?
        "Interesting to see Fig 2 showing that GHG forcing has tripled in the last century when GHG concentration has only increased by a factor of 1.5." Given that the zero point of this graph is, rather obviously, the effective forcings in 1880 don't you think it's an imaginative leap, to put it mildly, to say that the GHG forcing has tripled?
118582. RSVP at 18:18 PM on 31 May 2010
        Could global brightening be causing global warming?
        Bern I was talking about 250 ppm vs 380 ppm... a factor of 1.5 roughly. The units in Figure 2 depict energy per square meter, not concentration. In terms of the relationship between concentration and energy, concentration is the independent variable, while energy is the dependent variable. Energy normally increases as the square root of a linear change in the independent variable.
118583. HumanityRules at 18:05 PM on 31 May 2010
        Could global brightening be causing global warming?
        So what does figure 1 tell us? How much of the sun's energy is reaching the surface? This must be of some importance to temperature change? 3.Bern I think it's reduced methane.
118584. Bern at 17:35 PM on 31 May 2010
        Could global brightening be causing global warming?
        RSVP: the 1900 GHG value in Fig 2 is ~0.2, while the 2000 value is ~2.7 or so. That seems like much more than a tripling to me! It's rather scary to see the GHG forcing was growing exponentially from ~1940 through to the late 1980s or so, where it seems to have tapered off dramatically. Does anyone have any idea why the sudden drop in the rate of increase c.1990? Is it to do with changing patterns of energy use, or something else?
118585. RSVP at 17:12 PM on 31 May 2010
        Could global brightening be causing global warming?
        Interesting to see Fig 2 showing that GHG forcing has tripled in the last century when GHG concentration has only increased by a factor of 1.5.
118586. MikeCoombes at 15:31 PM on 31 May 2010
        Working out climate sensitivity from satellite measurements
        Thanks Riccardo for the comment For example, think about downwelling and upwelling and mixing of ocean waters. These movements are not well know and may produce a large unaccounted variability in the short run but tend to average out over longer periods. But we have a hundred years of data to average over. The change in energy from the sun between summer and winter over a hemisphere (N or S) is approximately constant and much larger than most other factors and the consequent temperature change is also large (I would guess about 20C - much more at the poles and less near the equator -) and also roughly constant but with more variability for the reasons you mentioned. I guess I should just try to calculate it. I recall Open Mind had a few blogs on how much various orbital factors affected how much sunlight a hemisphere received.
118587. villabolo at 15:22 PM on 31 May 2010
        Could global brightening be causing global warming?
        Did not Lord Monckton make an argument once for Global Cooling? You know, the one based on a falsified version of an UAH globally averaged satellite based temperature chart, conveniently cut off at 1998 to show an artefactual drop in temperature? Pray tell, Lord Monckton, which is it? Global Cooling or Global Warming through whatever means?
118588. johnd at 13:11 PM on 31 May 2010
        There's no empirical evidence
        cherrypicked at 11:46 AM, just to add to my earlier post to help get it into perspective and hopefully not further confuse the matter, temperature drops about 7oC for every 1000m increase in altitude above sea level, that is about 1oC for every 140m increase in height, all other things being equal.
118589. johnd at 12:40 PM on 31 May 2010
        There's no empirical evidence
        cherrypicked at 11:46 AM, the qualification "or" will apply if you consider how conditions can change given IR radiation is always from the warmer body to the cooler. The relative differences in state between the surface and the atmosphere can be that the surface can be warmer than the atmosphere, OR both the surface and the atmosphere are in equilibrium, OR the surface is cooler than the atmosphere. It is always going to be one OR the other depending on all the variables that combine to produce the climate that exists on this planet.
118590. cherrypicked at 11:46 AM on 31 May 2010
        There's no empirical evidence
        It can't be a bit of both as you suggest. Warming the atmosphere can only lead to warming the surface if at least some of the warming is directed downwards. Specifically, radiative trapping produces (some) surface radiative forcing. But that is not what Evans said. He said it is one *or* the other. He didn't say it's a bit of both. Also, the sentence makes no sense if we substitute "or" for "and", so it is unlikely a typo. However, "caused by" would fit.
118591. jfbarsoum at 11:22 AM on 31 May 2010
        Skeptical Science now a Nokia app
        For those of you with other phones (Pre, Android, etc.) you might consider using a good RSS reader app as a stop-gap. There are XML RSS feeds for both the ARguments and the Blog, so if you can read those feeds using a mobile reader, you're golden.
118592. cherrypicked at 10:58 AM on 31 May 2010
        There's no empirical evidence
        Thank you for the detailed article. I have a question? In the section, co2 traps heat, you quote Evans 2006: The results lead the authors to conclude that "this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming." Yet the opening sentence in the link you provide, Evans states: "The earth's climate system is warmed by 35 C due to the emission of downward infrared radiation by greenhouse gases in the atmosphere (surface radiative forcing) or by the absorption of upward infrared radiation (radiative trapping)." It is the use of the conjunction "or" that I am querying. Which is it? Is it surface radiative forcing, or is it radiative trapping? I am *not* suggesting the above statement in some way invalidates Evans' proof, but it does cast doubt on the mechanism responsible for the warming. For completeness, I must point out that this sentence does not appear in the linked article - only the abstract.
        Response: "Which is it? Is it surface radiative forcing, or is it radiative trapping?"
        
        A little from column A, a little from column B. Greenhouse gases both absorb upward infrared radiation which warms the atmosphere, and also scatter or reemit infrared radiation in all directions, some of which heads back to Earth.
        
118593. Bern at 10:56 AM on 31 May 2010
        Skeptical Science now a Nokia app
        doug: Are we talking a phone OS flame war, or a PC OS flame war, or both? Shall we have a flame war about what to have the flame war about? :-P John: very cool, more exposure for this wonderful site. Good to hear an update about the Android app - I await it with bated breath... Hmm, I'm pretty sure that shouldn't be "baited breath"... oh, no, a grammar flame war! :-D
118594. johnd at 09:41 AM on 31 May 2010
        Websites to monitor the Arctic Sea Ice
        Just to appreciate the difficulties in estimating ice volume, and the need for caution about drawing conclusions from relatively small changes in estimates, the accuracy that applies to measurements made needs to be taken on board. The acknowledged error involved in measuring ice thickness ABOVE the waterline is plus/minus 50mm. Because only about 10% of the ice is above the waterline this error multiplies to plus/minus 500mm which is very significant when first year ice is generally less than 2m thick, meaning less than 200mm freeboard and multi-year ice about 3m thick, meaning 300mm freeboard. All other estimates such as density have their own inbuilt errors, but the error involved in estimating actual ice volume comes down to this relatively large error involved in simply measuring the sea ice freeboard. Even as new technology and techniques improve the accuracy of measuring the ice freeboard, it will be still subject to a factor of 10. Even once that improved accuracy been established, it doesn't change the fact that all measurements obtained in the past will still have those large inbuilt errors which have to be taken into account when comparisons are made with any historical data.
118595. Berényi Péter at 09:25 AM on 31 May 2010
        Websites to monitor the Arctic Sea Ice
        #22 Riccardo at 06:47 AM on 31 May, 2010 you're just playing war games No, it's the US Navy's job, not mine. And they do play it all the time. It includes verifying the forecast systems operated by smart guys using independent means. I reckon they send out patrols to check model forecast occasionally, ordered to report back their findings. Understanding the ice thickness distribution and its variability is important in both short-term operational forecasts and longer-term climate studies. Model-derived ice thickness fields are useful in obtaining a large-scale, but detailed picture of ice distribution and, more importantly, an understanding of its temporal variability. #25 michael sweet at 08:11 AM on 31 May, 2010 the other is a derived number by a web blogger with unknown error bars You must refer to my attempt. But you are overestimating my role by saying the numbers are derived by me. The algorithm I have run is actually pretty straightforward, the curves come from the PIPS 2.0 24 hour forecast maps. As there are no error bars supplied by PIPS, of course I could not pull out one from thin air. All I can say is errors introduced by the transformation are negligible. Casting doubts does not contribute to understanding. As for sea ice volume, please check the article Has Arctic sea ice returned to normal?, this site.

        What the science says...

        Sea ice extent tells us what about the state of the sea ice at the ocean's surface, not what's happening below. Arctic sea ice has been steadily thinning, even in the last few years while extent increased slightly. Consequently, the total amount of Arctic sea ice in 2008 and 2009 are the lowest on record.

        BTW, ice volume graph provided by the Polar Ice Center does not have error bars either.
118596. Riccardo at 08:17 AM on 31 May 2010
        Climate sensitivity is low
        here is a more readable formatting of Lin 2010. ;)
118597. michael sweet at 08:11 AM on 31 May 2010
        Websites to monitor the Arctic Sea Ice
        I would point out that one estimate of volume is from ice scientists who have estimated their error and the other is a derived number by a web blogger with unknown error bars. You have to choose how you determine what data is worth considering. The difficulty in determining ice volume is one reason why NSIDC uses ice extent. The ice extent is a firmer number than the ice volume. With luck NSIDC will comment on this in their next monthly report.
118598. Riccardo at 07:53 AM on 31 May 2010
        Websites to monitor the Arctic Sea Ice
        Marcel, as i understand it they both "assimilate" data. Each day PIPS restart the forecast with actual data if their previous forecast was out more than a certain threshold. It's about the same process used for PIOMASS. I think the difference lies in the details. Apart from being the more recent of the two, PIOMAS includes a so called thickness and enthalpy distribution sea ice model which takes into account the rheology of ice and ice ridging. Apparently PIPS does not. I'm not able to go any further on these details, we should ask a specialist.
118599. Peter Hogarth at 07:36 AM on 31 May 2010
        Climate sensitivity is low
        I am not sure this paper has been mentioned yet. See Lin 2010. Obtains 3.1K for sensitivity, constraining the estimates a little to between 2.8K and 3.7K
118600. Marcel Bökstedt at 07:14 AM on 31 May 2010
        Websites to monitor the Arctic Sea Ice
        Hmm.. lets just leave what WUWT writes out of this equation. And it's best that BP does not annoy the Navy, they can be nasty if they decide to retaliate. It would still be interesting to explain the differences between the estimates of ice volume. Could it be that the fact that PIPS is essentially a forecast makes it less reliable? (Maybe PIOMAS can use data obtained later than the fact to estimate ice thickness?)

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