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Reflections on Ringberg

As previewed last weekend, I spent most of last week at a workshop on Climate Sensitivity hosted by the Max Planck Institute at Schloss Ringberg. It was undoubtedly one of the better workshops I’ve attended – it was focussed, deep and with much new information to digest (some feel for the discussion can be seen from the #ringberg15 tweets). I’ll give a brief overview of my impressions below.

As we’ve discussed previously, there are multiple classes of observational data that could provide some constraints on how warm the planet will get as CO2 increases (either on a multi-decadal timescale (TCR) or for the long term equilibrium (ECS)). Principally, there is paleo-climate data from previous quasi-equilibria like the Last Glacial Maximum or Eocene; evidence from the instrumental trends since the 19th Century; and climatological observations that correlate to longer term responses (either in the mean, seasonally or over interannual variations). Each class of data has its own problems, either in terms of observational quality, its relationship to sensitivity, or the level of simplicity of the underlying model.

The workshop spent a lot of time examining the explicit (and implicit) assumptions that underlie the methods and constructively criticising all of them to see how they can be best reconciled (because we are just looking for one number after all). Andy Dessler recorded his own talk on short term constraints and posted it already. Slides from the other talks are posted on the MPI website.

There were two major themes that emerged across a lot of the discussions: the stability of the basic ‘energy balance’ equation ($\Delta N = \Delta F - \lambda\Delta T_s$) that defines the sensitivity, $\lambda$, to zeroth order; and the challenge of estimating cloud feedbacks from process-based understanding. The connection occurs because the clouds are the cause of the biggest variation in sensitivity across GCMs.

The first topic was triggered by extensive evidence in models that there are structural variations associated with changes of base state, time variations, spatial variations and the different physics of each forcing that imply $\lambda$ needs to be thought of as more than constant. For instance, plotting $\Delta N$ against $\Delta T_s$ in an experiment with an abrupt forcing (such as 4xCO2) should give a straight line (red) if $\lambda$ were constant, but instead there is almost always some curvature implying that temperature changes a more for the same forcing change after a century or so than at the start (blue line).



That curvature implies that applying a strictly ‘constant $\lambda$‘ model to a limited set of observations (such as the trends over the last hundred years) is likely to bias any estimate of the sensitivity. Quantification of these issues is ongoing. Without a resolution though (or a set of reasonable corrections), efforts to combine multiple constraints without taking this into account are going to be flawed.


The cloud feedback discussion was extremely interesting since there are a multitude of different theorised effects depending on which clouds are being discussed (Mark Zelinka and Graeme Stevens did a great job in particular in explaining these effects). The variation in climate sensitivity in models seems to be dominated by the simulations of low clouds (which are a net cooling to the climate) which have a tendency to disappear as the climate warms. Whether this can be independently constrained in the observations is unclear.

The conversations around these issues got into multiple connected areas, including aerosol forcings, observational uncertainty, climate model tuning and independence, the nature of probability, Bayesian updating, detection and attribution, and internal variability. It looks like there will be some interesting upcoming papers on many of these aspects that will help clarify matters.

While the workshop wasn’t designed to produce a new assessment of the evidence, we did spend time specifying the problems there would be if equilibrium sensitivity was less than 2ºC or greater than 5ºC. Specifically, what would have to be true for all the evidence to fit? This was useful at underlining the challenge in shifting or constraining the ‘classic’ range by very much.

More generally, the workshop was a great example of how a diverse group (in attitude, background, temperament as well as the more usual classes), can tackle complex and difficult problems in a situation with only minimal distractions. Some of the these discussions were (to say the least) quite intense, but were all done in a spirit of constructive collegiality so nobody came to blows ;-).

As an aside, it also underlines the problems with a move towards more virtual conferences – I know of no online methodology to replicate the intensity or depth of the conversations, sustained over a week that we had here. Much in science can certainly be done fine by video conferencing (including a PhD defence I ‘attended’ in Paris, or for recent testimony to the Texas Legislature I gave by Skype), but the experience at this kind of focused workshops is really the hardest challenge to emulate.

83 Responses to “Reflections on Ringberg”

  1. 1
    Mike Haseler (Scottish Sceptic) says:

    Thanks for putting material and tweets online. A very interesting glimpse into the mindset of those behind the climate predictions.

  2. 2
    Paul S says:

    Graham Stevens

    Ahem, I believe that’s Graeme Stephens.

    Also, worst April Fools ever ;)

    [Response: Yes it is. (We’ve decided we can never top the Sheep Albedo Feedback post, and so we’ve stopped trying). – gavin]

  3. 3
    Thomas says:

    Please define terms. Everyone in your community may know what the definition of delta N and delta F are, but I doubt too many RC readers do. Without knowing something about the meaning of the terms, equations are almost meaningless.

  4. 4

    We’ve decided we can never top the Sheep Albedo Feedback post…

    Well, Sheep Albedo it ain’t, but there is this:

    NextGen Climate Hoax(e2) video

  5. 5
    John Benton says:

    It’s unfortunate the leading researcher in the climate sensitivity field, Nick Lewis, was not invited.

    [Response: It’s unfortunate you didn’t read the participant list before commenting. – gavin]

  6. 6
    David Williams says:

    As usual thanks Gavin! And thanks for the Sheep Albedo Post! I hadn’t seen it. Happy April Foold Day!

  7. 7
    CM says:

    The Sheep Albedo Feedback is indeed hard to bleat.

    Indeed, this very post underscores the significance of a variable lamb—duh.

  8. 8
    Gordon M says:

    Thanks for the link to the Sheep Albedo paper. Surprised the loyal opposition hasn’t picked up on that yet.

    On a slightly more serious note, I am intested in the time frames for TCR and ECS. The report mentions a ‘multi-decadal’ time scale for TCR. Can we pin this down a little tighter? Are we talking two or three decades or ten plus? It seems that this must be better defined if we are going to put a value on it. If I am thinking 20 years and you are thinking 100, we would have drastically different values for the TCR even if we are in exact agreement on the curve. Could you shed some light on that.

    The ECS definition is certainly clearer conceptually, but it isn’t clear how long it takes to achieve equilibrium (or maybe 90% of equilibrium would be a better bench mark). I assume we are talking more than a century now, but is there a more precise estimate?

  9. 9
    Gordon M says:

    CM, that was baaaaad. It is clear the author was trying to pull the wool over our eyes.

  10. 10
    LanceOlsen says:

    I’m (again) reminded of a comment attributed to Enrico Fermi : “I was confused about this topic before this conference, and am confused about it now, but at a higher level.”

    Ah, the joys of science ;)

  11. 11
    Matthew R Marler says:

    2, gavin in line, thank you for the link. It was dear.

  12. 12
    Matthew R Marler says:

    2, gavin in line, thank you for re-linking.

  13. 13

    I have been trying to start a political movement to repeal the Laws of Thermodynamics.

    Tried to confine the suggestion to April 1st, but in so many discussions it seems like the only solution.

  14. 14
    Russell says:

    Top the Sheep Albedo Feedback Post ?

    You’d have to boil the Easter Bunny .

  15. 15
  16. 16
    Russell says:

    Don’t get your ears in a twist, Eli– boiling the Easter Bunny is Watts idea.

  17. 17
    Susan Solomon says:

    Gavin, how about a physical explanation for yr red, blue behavior? References?

  18. 18
    Tim Merlis says:

    Re: Susan. Mike Winton, Isaac Held, and Ken Takahashi have a 2010 J. Climate paper on the origin of the curvature in the relationship between global-mean net radiation at the top-of-atmosphere and surface temperature. The basic message is that 1 W/m2 of ocean heat uptake has a bigger effect on global-mean surface temperature than 1 W/m2 of radiative forcing, but the ocean heat uptake is transient. It’s unfortunate that this didn’t make a prominent appearance in AR5. Isaac Held has a couple of blog posts about this, including this one from 2011: http://www.gfdl.noaa.gov/blog/isaac-held/2011/03/19/time-dependent-climate-sensitivity/

  19. 19
    Ray Ladbury says:

    Gavin,
    Regarding your point about the unique opportunity offered by conferences for hashing out difficult issues–I think this is extremely important. Unfortunately, counters of legumes now equate conferences with wasteful excess. I am particularly concerned for younger colleagues who are being deprived of this experience. At the same time, the denialati cite the air travel involved as evidence that the scientists don’t believe the challenge is severe.

    I really wonder how the scientific community is going to come to grips with this threat to the way science gets done. Can people really imagine the Bohr-Einstein debates being conducted via email and teleconferences?

  20. 20
    Thorsten Mauritsen says:

    @ Gavin, thanks for the summary, I to enjoyed very much the meeting, and the intense discussions.

    @ Susan, there are several pathways to curvature, the more popular being that if warming is delayed in regions higher local sensitivity (e.g.) high latitudes, then the global mean feedback can differ on far and slow timescales. There could be other reasons too, though, it’s a developing research field. There was some of this in AR5, but the connection to ECS estimates was weak.

  21. 21
    Chris Colose says:

    Hi Tim (#18), good to see you here-

    I know you know this, but for everyone else, Brian Rose (et al.) also has a pretty elegant paper here on the time-evolution of sensitivity in this context.

  22. 22
    Thomas Frölicher says:

    A quick follow up on Tim’s comment #18, which might be of interest: Mike Winton, Jorge Sarmiento and myself have published a follow-up study showing that even if emissions stop, the Earth could warm for centuries using GFDL’s ESM2M model. We show that this occurs in spite of a decline in radiative forcing that exceeds the decline in ocean heat uptake—a circumstance that would otherwise be expected to lead to a decline in global temperature when using the simple energy balance model described in the post.
    http://www.nature.com/nclimate/journal/v4/n1/full/nclimate2060.html

  23. 23
    Russell says:

    Gavin should try to see to it that the Erice organizers, get to hear both sides of the story at future climate related workshops there- schmoozing by Singer’s cohort has turned it into a sort of Sicilian Heartland Conference in recent years, with predictible op-ed fallout in Europe.

  24. 24
    Matthew R Marler says:

    Thank you for the post. I am glad that you highlighted the complications of the cloud feedback.

    My three questions for today:

    1. Do you (or most people, or anyone other than me) distinguish the warming of the surface from the warming of the middle and upper troposphere? I ask because transfer of energy from upper troposphere to space is mostly by radiation, whereas most of the transfer of energy from the surface to the atmosphere and space is by non-radiative transfer (advection/convection and evapotranspiration.) A single governing equation for all seems a priori a simplification too far. If you think of the system as being in steady-state, at least approximately, instead of equilibrium; and if you think of the effect of CO2 increase to be a change from one steady-state to another, it would not necessarily be the case that the temperature increase of the surface, middle troposphere, and upper troposphere to be the same. (This is a phramacokinetic view — if you increase the infusion rate of a drug until a new steady-state has been achieved, you would not necessarily have equal increases in the concentrations in the plasma and in the target organ.) A paper by Laliberte et al earlier this year in Science Magazine looked at energetic constraints on steady-state related to increased water vapor.

    2. If the surface were to warm by 1C, how much would the advective/convective, evapotranspirative, and radiative energy transfer from the surface increase? You can also add in the rate of transfer from the ocean surface to the deeps.

    3. At the ocean surface, where H2O is nearly always evaporating and the wind seldom stops blowing completely for long, what really happens when the power of the DWLWIR increases by about 1% or less?

  25. 25
    Chris Dudley says:

    Thomas (#22),

    There are a number of papers showing this kind of behavior, though not necessarily for the same reason, but when emissions stop at a range of concentration level, it is the higher concentration stopping points that fail to cool, or warm as you describe. Your stopping point is around 4xCO2 which would make it a high stopping point.

  26. 26
    S. Molnar says:

    Re Ray Ladbury’s comment 19: I could point out that Bohr and Einstein didn’t generally use airplanes to get together, but it’s certainly true that the scientific community is much more geographically diverse these days. Still, ships can be reasonably efficient with respect to carbon (sails!), and, given the abundance of stories about shipboard encounters in the old days, I wonder if both science and the arts haven’t lost a valuable venue for fruitful meetings.

    I would also add that the problem extends to academics in general, including the tendency towards online courses as a substitute for in-person courses. Yes, they can reach a wider audience, and you don’t have to put on trousers to attend, but it’s just not the same.

  27. 27
    Steve Fish says:

    Re- Comment by Matthew R Marler — 2 Apr 2015 @ 3:18 PM, ~#23

    Matthew, it is my understanding that all heat loss from the earth to space is by radiation. Water vapor from evapotranspiration has to rise upward until the lapse rate causes condensation back to water. Thus, latent heat is stored until it can be released and then, subsequently, radiated to space, and this process is slower than radiation from the surface. The earth is contained in the very efficient thermos bottle of space.

    Steve

  28. 28
    Jef says:

    Similar question to Matthew’s albeit much more layman.

    Clouds and aerosols shade the surface but is there not still heat trapped in the atmosphere above them but below the GHGs in the higher atmosphere? In fact isn’t the solar radiation warming the clouds and aerosols and therefore the atmosphere directly?

    Thank You!
    Jef

  29. 29
    Pete Dunkelberg says:

    Matthew R Marler,
    If you have a supercomputer in the basement, perhaps Gavin will send you the code for a GCM and you can see for yourself that there is more to it than “A single governing equation….”

  30. 30
    Matthew R Marler says:

    27, Steve Fish: Water vapor from evapotranspiration has to rise upward until the lapse rate causes condensation back to water. Thus, latent heat is stored until it can be released and then, subsequently, radiated to space, and this process is slower than radiation from the surface. – See more at: http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg/comment-page-1/#comment-628048

    my comment at 24 contains an error: I ask because transfer of energy from upper troposphere to space is mostly by radiation, whereas most of the transfer of energy from the surface to the atmosphere and space is by non-radiative transfer (advection/convection and evapotranspiration.) – See more at: http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg/comment-page-1/#comment-628048

    It should say “transfer of energy from the surface to the atmosphere (whence radiated to space) is by non-radiative transfer etc”. I apologize for the error.

    Now about this: this process is slower than radiation from the surface.

    The energy flow estimates in Stephens et al show a greater rate of transfer from the surface to the upper troposphere by non-radiative than by radiative means. Which mechanism is faster at any particular time and place depends on the circumstances then and there: thundercloud build-up and rainfall versus cool, sunny day for example.

  31. 31
    Thomas Frölicher says:

    Chris,

    the model also warms at lower atmospheric CO2 stopping points. Keep in mind that there are studies using simple models (see Pierrehumbert 2014) suggesting that when climate sensitvity becomes very high, there would be warming after emissions have ceased. In our paper, I argue that we can not rule out the possibility that there may be long-term commited warming in AOGCMs at even lower climate sensitivity.I think the TCR/ECS ratio (or realized warming fraction) is key here to understand the long-term climate response.

  32. 32
    Carrick says:

    Isaac Held has a nice discussion of the time dependence of climate sensitivity (relating to the figure that Gavin showed above) here.

    One of the papers he references is Winton 2010

  33. 33
    Matthew R Marler says:

    29, Pete Dunkelberg: there is more to it than “A single governing equation….”

    Of course there is.

    Gavin wrote this: There were two major themes that emerged across a lot of the discussions: the stability of the basic ‘energy balance’ equation () that defines the sensitivity, – See more at: http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg/#sthash.Btx3NkIK.dpuf

    He went on to explain that lambda should not be treated as a constant, but otherwise focused on a single balance equation. Then he went on to the complexities of cloud feedback, one of my long-term favorite topics. It does not require a copy of computer code to realize that the use of a single balance equation is likely to lead to inaccurate answers. Consider the paper by Laliberte et al in Science Magazine earlier this year, about the thermodynamic constraints imposed by increasing the water vapor content of air; it is the first paper I have seen looking at the climate system as approximately a steady-state rather than an approximate equilibrium. Thought of that way, there have to be a lot of energy flux balance equations.

  34. 34
    Steve Fish says:

    Re- Comment by Matthew R Marler — 3 Apr 2015 @ 1:06 AM, ~#30

    Matthew, to clarify what I said- All heat that leaves the earth from the surface or the atmosphere is by radiation. All. The portion from evapotranspiration is relatively small and slower because of the delay prior to being radiated while the heat remains latent. There are many illustrations of these processes such as this one by Chris Colose: https://chriscolose.files.wordpress.com/2008/12/kiehl4.jpg?w=480&h=350

    Steve

  35. 35
    Pete Dunkelberg says:

    Mathew R Marler, apologies if I misunderstood you. I thought you might be thinking of a single equation for more than just sensitivity. You started with “Do you (or most people, or anyone other than me) distinguish the warming of the surface from the warming of the middle and upper troposphere?” (Yes of course.)

    There is at first a single defining equation for sensitivity, but then things happen. Now I think I understand your question better.

  36. 36
    Chris Colose says:

    Steve Fish, not *my* figure, but thanks :-)

    The short and lazy answer to Matthew Marler’s question about the column energetics that bring the system back to equilibrium is that GCMs do of course represent evaporation, sensible heating, etc in ways that are undoubtedly imperfect (e.g., via “bulk formulas” that transfer energy down-gradient of temperature or humidity differences between the surface and air aloft), but they are free to evolve in climate change scenarios in ways that are physically self-consistent. For example, one cannot increase evaporation/precipitation arbitrarily since energetic limitations come into play- this comes up in discussions of the hydrologic cycle in global warming experiments, where global mean precipitation/evaporation increase rather slowly, certainly more slowly than the column water vapor amount.

    But, at least to first-order, why can we usefully adopt a top-of-atmosphere (TOA) perspective to determine surface temperature, even though the surface energy budget must also close in equilibrium (and which includes many different non-radiative terms)?

    To begin with, remember that CO2 (or whatever) causes some net change in the TOA energy budget, perhaps by reducing the outgoing longwave radiation (OLR) by ~8 W/m2 instantaneously (like a quadrupling of CO2), an imbalance that must gradually shrink in time. After sufficient time evolves, we reach a new equilibrium defined by a near zero net TOA radiative imbalance (the figure in the post shows that this evolution may not follow a linear track, but ignore this for now). Thus, the eventual zero anomaly can be split up into a forcing and an equal but opposite flux arising from all the processes in the column that conspire to bring it back to equilibrium.

    The partitioning of these processes is a bit artificial. For example, we can ask what the flux change would be if the column warmed uniformly (by the same amount as the surface warming) in the vertical, holding all else fixed? We call that a Planck feedback. As Matthew correctly intuits, this uniform warming doesn’t actually happen, so we can ask how the flux would change owing to departures from vertical uniform warming, by subtracting off the surface temperature anomaly along the whole dT(z) curve. We call that a lapse rate feedback. One can similarly construct a feedback analysis by perturbing the humidity, holding all else fixed, etc.

    There are many ways to partition all of the column adjustments that must eventually act to counteract the imposed radiative forcing. Another way to do this is to allow the specific humidity to evolve in a way that keeps the relative humidity fixed, thus eliminating a water vapor feedback from the analysis and re-defining the feedback owing to the temperature adjustment in the column. However this partitioning is done, we are ultimately interested in determining (1) the new T(z) curve, and (2) Ts given the T(z) curve. Number 1 is not as unconstrained as it might seem. As Matthew noted, radiation is not an efficient vertical energy transfer process in the troposphere. This is because the troposphere is very opaque, and so the temperature gradient that would need to exist for the troposphere to be in radiative equilibrium would be far steeper than in reality. Such a lapse rate is dynamically unstable, and so the column convects. Radiation is thus always destabilizing the troposphere, and convections acts to move energy upward until a stable lapse rate is obtained, corresponding to an appropriate adiabat…this is why we have a troposphere, and one can identify tropospheres more generally by virtue of their temperature structure following such a curve. This is true in climate change as well, so to first-order one can determine any point along the T(z) curve by knowing the temperature at one point.

    Problem (2) depends on the nature of your surface budget, but as a starting point, we can assume that the surface budget is acting to keep surface temperatures close to the temperature of the air right above the surface. This replaces all of the complicated terms in the surface budget with the assumption that Ts is equal to the lowest-level atmospheric temperature. This works especially over moist surfaces. So evaporation doesn’t control sea surface temperatures, but it does couple that surface temperature to the overlying air temperature, but importantly one needs to satisfy the TOA budget to determine what that temperature is, i.e., it wouldn’t be correct to assume there’s an upper bound on SSTs after which evaporation is so efficient that the temperature can’t increase much more. There’s situations where one can’t just get away with a TOA perspective assuming the surface budget to be “dragged along” in the process, if you’re over a changing desert surface or polar region, etc. The vertical structure of warming and “stability” of the polar atmosphere comes up in discussions of mechanisms behind arctic amplification.

    It turns out there’s many complicated physical and dynamical processes wrapped up in some of the feedbacks we identify from a TOA perspective, particularly the “lapse rate feedback.” I haven’t made an attribution statement about everything that must occur to keep the lapse rate what it will eventually be (Ming Cai and Jianhua Lu have made attempts at reformulating our framework to think more explicitly about such things, but it hasn’t quite caught on, perhaps more because of its elegance/necessity, but I don’t speak for everyone). Like most things, there’s not a single correct way to think about all this, but the TOA framework is exceptionally useful precisely because we can write things like ∂OLR/∂Ts, due to the way the whole column behaves as a result of all the dynamics/processes occurring, but in ways that don’t necessarily require detailed accounting of them all.

    Obviously, when you move up the hierarchy of model complexity such simple explanations must be replaced by the simulation of processes. That’s how we move forward and build credible answers, but the underlying framework of how a planet’s temperature is determined has been securely intact for well over 50 years (Manabe and Wetherald a good entry point).

  37. 37
    Frank says:

    Gavin wrote: “The variation in climate sensitivity in models seems to be dominated by the simulations of low clouds (which are a net cooling to the climate) which have a tendency to disappear as the climate warms. Whether this can be independently constrained in the observations is unclear.”

    According to Isaac Held, climate models predict that the relative humidity over oceans will have to rise about 1% (a 5% increase in 1 – RH) to suppress surface evaporation which would otherwise rise at 7%/degC and create a surface energy imbalance (because DLR increases with warming nearly as fast as OLR). This causes me to speculate that an increase in boundary layer humidity could increase the likelihood of clouds at the top of the boundary layer. In the past, haven’t boundary layer clouds been considered to be one of the weak points of AOGCMs?

    http://www.gfdl.noaa.gov/blog/isaac-held/2014/06/26/47-relative-humidity-over-the-oceans/

  38. 38
    Jim Eager says:

    Steve Fish, you need to revise that statement to:

    “All heat that leaves the earth to space is by radiation.”

    Heat leaves the surface by radiation, conduction, convection and evapotranspiration (latent heat).

  39. 39
    Matthew R Marler says:

    34, Steve Fish: All heat that leaves the earth from the surface or the atmosphere is by radiation. All. The portion from evapotranspiration is relatively small and slower because of the delay prior to being radiated while the heat remains latent.

    The flow diagram of Stephens et al, and the earlier flow diagram by Trenberth et al, show more energy leaving the Earth surface by non-radiative than by radiative mechanisms. Are you asserting that they are wrong?

  40. 40
    Matthew R Marler says:

    36, Chris Colose: But, at least to first-order, why can we usefully adopt a top-of-atmosphere (TOA) perspective to determine surface temperature, even though the surface energy budget must also close in equilibrium (and which includes many different non-radiative terms)?

    How can you tell that the TOA perspective, accurate to “first-order”, is accurate enough to calculate the change in the mean surface temperature (following an increase in forcing at the surface) to the first significant figure? My calculation suggests that it might not be able to; if my calculation has an accurate result then it can not.

    I think that separating the climate system into regions (surface geography) and layers, and working with approximate steady-state calculations instead of equilibrium calculations, will give a different answer for the change in the surface temperature.

    I expect the Romps et al and Laliberte et al Science papers to stimulate a large literature that moves beyond equilibrium approximations (though I recognize that Romps et al got the 10% change in CAPE [per C increase in surface temperature] from equilibrium approximations for the moist adiabatic lapse rate) to approximate steady-state approximations (redundant “approximate” on purpose.)

    At minimum, the surface, mid-troposphere and upper troposphere are never in equilibrium, but are continually changing total energy content and temperature. Ignoring that leads to an error that is larger than the effect being calculated, and biases the calculated change in Earth surface temperature upward.

  41. 41
    Steve Fish says:

    Re- Comment by Jim Eager — 3 Apr 2015 @ 5:14 PM, ~#38

    Jim, your suggested change to my comment (currently at #34) – “All heat that leaves the earth to space is by radiation”- is accurate and also what I said in my first reply to Matthew (currently at #27). In #34, I simply assumed that in my restatement of my point that it was understandable that if energy was leaving the earth from the surface and the atmosphere it was going to space. Where else could it go?

    Steve

  42. 42
    Steve Fish says:

    Re- Comment by Matthew R Marler — 3 Apr 2015 @ 5:54 PM, ~#39

    The global energy flow illustration I attempted to link to on Chris Colose’s website is an update to the widely cited article by Kiehl and Trenberth (1997). I had saved the updated image and Chris’s website separately and posted the wrong link (sorry Chris). The illustration clearly shows that thermals and evapotranspiration account for a total of 97 watts per square meter delivered to the atmosphere for re-radiation to space, while total radiation to space is 341 watts per square meter. Could you provide a link to the article you are referencing that is, apparently, very different than what I understand is correct?

    Chris’s article is at: https://chriscolose.wordpress.com/2008/12/ . Scroll down to “An update to Kiehl and Trenberth 1997” for a nice colored rendition of the figure.

    For a free access PDF to the Kiehl and Trenberth article, “Earth’s Annual Global Mean Energy Budget” go to: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0477%281997%29078%3C0197%3AEAGMEB%3E2.0.CO%3B2 which has the image (Fig. 7) in black and white. This earlier figure is only slightly different than the updated one.

    Steve

  43. 43
    Matthew R Marler says:

    42, Steve Fish: The illustration clearly shows that thermals and evapotranspiration account for a total of 97 watts per square meter delivered to the atmosphere for re-radiation to space, while total radiation to space is 341 watts per square meter. – See more at: http://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg/comment-page-1/#comment-628134

    My comments are addressing the transfer of energy from the surface to the atmosphere, which is dominated by non-radiative mechanisms. Of course the energy transported to the upper troposphere (for example) is then radiated to space, and is counted in that radiated energy. I’ll put up the full reference tomorrow.

  44. 44
    Hank Roberts says:

    A fiddly detail:

    Of course the energy transported to the upper troposphere (for example) is then radiated

    randomly in all directions — up, down, and sideways — and some of that goes away

    to space

  45. 45
    JCH says:

    There is also around 75 wm2 of SW absorbed by the atmosphere.

    Atmosphere is not surface, but from then on it is the same process, right?

  46. 46
    Matthew R Marler says:

    Here is the Graeme Stephens et al reference: Stephens, G. L., J. Li, M. Wild, C. A. Clayson, N. Loeb, S. Kato, T. L’Ecuyer, P. W. Stackhouse Jr., and T. Andrews (2012), An update on Earth’s energy balance in light of the latest global observations, Nat. Geosci., 5: 691–696.

    Here is the link:
    http://www.nature.com/ngeo/journal/v5/n10/abs/ngeo1580.html

    I have not been able to copy and paste the diagram, which is behind the paywall at the link.

  47. 47

    #43–“Dominated by non-radiative processes…”

    No, I think not. The surface radiates ~400 Wm2, per the updated K & T diagram. The ‘non-radiative processes’ amount to about 1/5 of that.

  48. 48
    Steve Fish says:

    Re- Comment by Matthew R Marler — 5 Apr 2015 @ 10:43 AM, ~#46

    Matthew, figure 1 in Stephens et al (2012) is only a small adjustment to the original Kiehl and Trenberth (1997) article that I linked to. Sensible heat (SH in Stephens, thermals in Kiehl) and Latent heat (LH in Stephens, evapotranspiration in Kiehl) are much less than the radiant return to the atmosphere and, as I have said several times, all heat leaving the earth to space is by radiation. This is pretty basic stuff.

    Steve

  49. 49
    Pete Dunkelberg says:

    Aha an actual reference at last. google scholar provides the paper
    scholar.google.com/scholar?cluster=17794623626267088926&hl=en&as_sdt=0,10

    and the cites, for instance this one:
    http://www.researchgate.net/profile/Matthew_Marler/publication/273575812_Climate_Sensitivity_to_a_Doubling_of_the_Atmospheric_CO2_Concentration/links/55061c0c0cf24cee3a050a25.pdf

    You may find a 2012 comment on the 2012 paper around the middle of this page:

    http://www.realclimate.org/index.php/archives/2012/11/short-term-trends-another-proxy-fight/comment-page-1/#comment-292460

    Is it fairly consistent with CMIP5?

  50. 50
    Matthew R Marler says:

    Does the work required to raise the sea level 4mm put a constraint on how much the surface and deep ocean temperatures can be increased by an extra 4 W/m^2? Where the sea is 3,000 meters deep, wouldn’t that be equivalent to raising 3,000 m^3 of water 2mm? If the “equilibrium” calculations show that it is possible, how rapidly can the work be performed if it is powered by 4 W/m^2?

    My other comments today seem to have been devoured by a “server unavailable” response.


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