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Unforced variations 3

Filed under: — group @ 21 October 2010

Here’s an open thread for various climate science related discussions, to prevent more off-topic clutter everywhere else. We have some good posts coming up, but if you want to discuss something you read in the media, saw in a press release or just wanted to ask about, this is the time.

Some interesting things we’ve seen recently include discussions on the epistimology of climate modelling, Andy Dessler’s adventures in debate land and his new paper on water vapour trends, and a review of trends in the Columbia glacier. Have at it.

Addendum: Kevin McKinney has beaten us to the mention of this, but another recent article of importance is a thorough review of the state of knowledge of drought, past and future, by Dai.  The article is open access here.

573 Responses to “Unforced variations 3”

  1. 151
    adelady says:

    TTTM. Just had another look at your questions and everyone’s responses.

    I think you’re showing signs of the “house of cards” problem, total collapse if something is found to be wrong. But science isn’t a house of cards, it’s a jigsaw puzzle. Someone can pick up a piece and say look, this will only fit if those red (or yellow or blue) pieces belong to the car in the background not the flowers in the foreground. If they’re right, a handful of pieces have to be re-fitted into the right places. The edges, the trees, the boats on the water are all absolutely fine. The picture as a whole won’t change even if some features become more or less prominent.

    The house of cards approach would mean that the whole thing has to be done all over again. The jigsaw approach just means that we have to re-examine the parts that look a bit odd.

    It’s _not_ a house of cards.

  2. 152
    Fred Moolten says:

    To Henryp (120) – Atmospheric greenhouse gases absorb and emit in the near-infrared and UV, warming the atmosphere but reducing the energy transmitted to the ground. The effect is small compared with the “greenhouse” forcing due to absorption of terrestrial radiation. More importantly, it is dominated by water vapor, with CO2 contributing a much smaller percentage. A useful quantitative source is the Kiehl/Trenberth paper, which includes the now famous energy budget diagram, at Earth’s Energy Budget

  3. 153
    HenryP says:

    Henry@Barton Paul Levenson (on question 120):
    I am looking for answers to two simple questions, you advise me to buy two books.If you have the answers in the right dimensions, why don’t you give it. If you admit that you cannot provide me with the answers, then you have to feel very bad (if you are an expert on CO2).
    ( I am just a simple chemist living in South Africa trying to figure out what is wrong with my carbon footprint).

  4. 154

    #126 & #131 TimTheToolMan

    I think you don’t understand the difference between the confidence in the detectable signals that are robust in nature and have relevant verifiability in multiple methods or disciplines, and the noise, where the models are clearly not yet able to discern all the minor signals between those signals and the various processes that are involved.

    Your what if scenario is a dream, a fantasy, a red herring. You have no scientific basis for it, it is a dead parrot. It’s not sleeping, it’s not pining for the fjords, it’s a dead parrot. It’s bleedin’ demised, expired, no longer alive. You can wave it in the air. You can through it so as to simulate flight but you can have no scientific basis for pretending it’s alive.

    #133 Bob (Sphaerica)

    Good point. I was thinking along the same lines ;

    October Leading Edge: The Cuccinelli ‘Witch Hunt
    Fee & Dividend: Our best chanceLearn the IssueSign the Petition
    A Climate Minute: Natural CycleGreenhouse EffectClimate Science HistoryArctic Ice Melt

  5. 155

    150 (Dan H.)

    …due to the heavy reliance on the models.

    Please justify this statement, and clarify. I see no truth to it, but perhaps I don’t understand entirely what you mean by it.

  6. 156
    Maya says:

    “the implication to climate science if a significant flaw is found and the risk to science that the increasing reliance on models has created.”

    Then you adjust the models and go forward. What else were you expecting?

    As for the risk, it’s a moot point. There is no magical “increasing reliance”. Climate science is not an experimental field, so they’ve always had to use models, whether it was a computer simulation or some guy with pencil and paper doing calculations to try and figure out what happens. Even a mathematical equation describing the behaviour of a block of wood sliding down an incline is a model in the broadest sense. You can’t say there’s an increasing reliance on something that has always been in use.

  7. 157

    henryp, (@151 or so) your actual question earlier was:

    “So, my question is: how much cooling and how much warming is caused by the CO2? How was the experiment done to determine this?”

    Perhaps Barton’s response is a clue that the answer isn’t as simple as you imagine? Folks often ask for “the paper” that proves AGW, or the answers this or that question on the topic. Many times it turns out that there’s a whole lot more past work that has gone into the topic than any of us amateurs could have imagined.

    Now, I don’t have the answer to your question; and, since I don’t even “play an expert on TV” I don’t feel bad about that. But it sounds as if you’re interested in results at a particular location, not some kind of global average, and I do know that the contribution of CO2 is going to vary a lot based upon location, time of day, seasonal variations, and the weather conditions (especially cloudiness.)

    Personally, I think Barton’s response was potentially pretty helpful–and I’m certain it was intended as such.

    By the way, the data you were using echoes what Svante Arrhenius used way back in 1896, funnily enough:

    Global Warming Science And The Dawn Of Flight: Svante Arrhenius

  8. 158
  9. 159
    Septic Matthew says:

    86, t_p_hamilton.

    That is not an adequate response. Water and air will both be warmer, upper atmosphere cooler, and the land/water difference will be greater in summer so the winds (e.g. from the Sahara to the N. Atlantic) will be greater and more dust-laden. It is not clear that any prediction follows from all that.

    If the number of cyclones stays the same on average but the number of high-intensity cyclones increases, then the average ACE will increase, and the change in average ACE will be as detectable as the change in average temperature.

    After hurricane Katrina, and again a few days ago from a Swiss re-insurer, there were warnings of increased frequency of major cyclones. The warning from the insurer was that New Orleans should improve its land use, including major reforestation. Like much good advice, that is good advice whether the frequency of major hurricanes does or does not increase.

    If someone has a comprehensive and well written exposition of how increased temps are supposed to lead to increased/unchanged/decreased cyclone intensities, I would like to have the link. Nothing I have found on my own to date includes all the factors.

    Readers here must have seen (or I can retrieve a link) the report that land-use changes have resulted in reductions (10% – 15%) in the average speeds of recorded winds around the world. Is that not a surprise?

  10. 160
    Hank Roberts says:

    > the models which currently make up the tail ends

    What are you talking about? Name one.

  11. 161
    Hank Roberts says:

    Maybe this would help clarify TTTM’s question.

    Here’s an idea that differs from what’s in the models:

    “Cryo-Hydrologic (CH) warming is proposed as a potential mechanism for rapid thermal response of glaciers and ice sheets to climate warming. We present a simple parameterization to incorporate CH warming in thermal models of ice sheets using a dual-continuum concept, which treats ice and the cryo-hydrologic system (CHS) as overlapping continua with heat exchange between them. The presence of liquid water in the CHS due to surface melt leads to warming of the ice. The magnitude and time-scale of CH warming is controlled by the average spacing between elements of the CHS, which is often of the order of just 10’s of meters. The corresponding time-scale of thermal response is of the order of years-decades, in contrast to conventional estimates of thermal response time-scales based on vertical conduction through ice (∼102–3 m thick), which are of the order of centuries to millennia. We show that CH warming is already occurring along the west coast of Greenland. Increased temperatures resulting from CH warming will reduce ice viscosity and thus contribute to faster ice flow.”

  12. 162

    The Gordon Bonan paper is interesting, and it might seem to support the argument here made at realclimate by a commenter against forestation in deserts. That argument asserted that the albedo change caused by forests would cancel heat balance benefits of the CO2 sequestration.

    Bonan’s statement refers to Northern Boreal forests which would be replaced by snow, were they to be destroyed. Thus, the albedo of snow would be compared with that of forests and the conclusion, “The climate forcing from increased albedo may offset the forcing from carbon emission so that boreal deforestation cools climate (8)–” can stand.

    The commenter does not show awareness of the integrative effect of forests, since the amount of CO2 sequestered in the forest increases with time and albedo change is a roughly one time change.

    Bonan may understand this since he is discussing fully formed forests that might be mowed down at one time, so the CO2 dumped into the atmosphere is a one time event and so is the albedo change. However, Bonan is talking about snow, not dirt.

    For the massive forest project I am discussing, the albedo change would be roughly a one time event as the trees first shade the ground. From that point on, the addition of forest mass is an increment each year that sequesters an increment of CO2.

    [Response: No. A change in albedo affects the radiative forcing as long as it remains in the changed state. It’s not a “one time event”. As for the statement on “dirt”, the albedo of much of the arid lands is pretty high, due to low vegetative cover, low albedo of seasonally dry grasslands, and/or low organic matter in the soil. Such areas will have large albedo changes if forested, especially to conifers. You also have to consider the effects of increased evaporation (cooling of the land surface but who knows what effects due to water vapor and clouds). Bonan’s take home point is that these conversions ain’t so simple to evaluate as might first appear.–Jim]

    I wonder if Bonan was including the loss of the underground root structure in his statement, that is, the work referenced by his statement. If not, the reference might be very much in error.

    The study offered by link here said 80% of carbon is in root structure, and if that is so, my calculations could be showing more land required than would be needed.

    Sorry that I am not keeping up with this very well, but I will try to find that link, regarding work in Tibet if I recall correctly.

  13. 163
    John Westbrook says:

    While looking up something written by John Christy recently, I came across the following short item also written by Christy in 2008:

    There is no doubt that Christy has some impressive scientific credentials, but reading the above makes you wonder how well he manages to keep his science pure…


  14. 164
    Leonard Evens says:

    TTT says

    “In my opinion there is a very real possibility that the models are seriously flawed simply because the climate processes are so complex and many of them are not yet well understood.”

    This seems to be his main point. But unless he comes up with something specific which might be a flaw, there really isn’t any way to deal with this complaint. He seems to be arguing that since it is all so complicated, one should be wary about relying on models which you can’t be completely sure about. And it seems to me that this is really what he wants to discuss.

    Okay, let me give it a try. Climate is very complex and we don’t understand it as well as we would like. So we should not be doing large scale experiments on the atmosphere, the results of which we can’t predict with any certainty. But adding to the atmosphere greenhouse gases in the amounts we have been doing, and seem determined to continue to do, is just such an experiment. Anyone who is conservative about fiddling with our world in dramatic ways should be worried about that.

  15. 165

    In mine of 4:01 PM above:

    Reference to the Gordon Bonin paper was from moderator Jim on comment #99 by ccpo.

  16. 166

    I try to hit the main points of the water and tree project in the following:

    Standing Forests Solve Global Warming At No Cost
    The game winning answer to global warming is to create standing forests, where every ton of newly existing forest mass, on a sustaining basis, compensates by CO2 capture for the burning of a ton of coal, approximately. Key to this solution is distribution of water in North America on a continental basis.

    I have been dismayed by promotion of electric vehicles with implicit increased use of electricity and the associated increase in CO2. Viable, large scale solutions to this problem have been absent. But I have been shocked by the planning put forward by the US EPA ** regarding ‘carbon’ capture and sequestration (CCS), where the capture cost burden per ton of coal used would be up to $180-$320. This would be for capture of CO2 only, with additional costs for transportation and pumping it into caverns being not addressed, but acknowledged as additional expense.

    Thus motivated, I looked for a better solution, and found that China seems to have taken the lead over our environmentalists in this very practical matter. A year ago, in a speech about how China was planning to react to the global warming problem, President Hu spoke of “forest carbon”. ***
    It is not a big step to think that this kind of solution would be possible in North America, Brazil perhaps, and other places yet to be identified. It is a big step to think big about water distribution that would be needed to accomplish CCS on the needed scale, but in North America this is within reach, with the action of wise government assumed. Of course there would be a need for due diligence in protecting Northern ecosystems, as well as due deference to rights of others. The goal of CO2 mitigation is not just our concern, so there would seem to be motivation for Canada to lend their essential support to such a project.

    Every ton of forest mass, that exists on a sustaining basis, sequesters CO2 sufficiently to compensate for the burning of a ton of coal, approximately. As it grows, it captures that CO2 from the atmosphere. Mature forests must be maintained and harvested wisely, and new forests must continue to grow.

    Using minimally productive land in selected regions, a fifty year project should be possible, where fifty years of coal fired power plant operation would be supported. In this time we would need to solve the problems of nuclear waste, so that there could be an eventual transition to that form of energy. During this fifty years, we would also need to work toward minimizing the amount of energy needed for our vehicles.
    This forest project, along with ancillary agricultural development, would be quickly self supporting. We know about the agricultural results from the latest California Aquaduct project implemented in 1963 through the California Central Valley. The forest part would be something new.
    The immediate benefit of such a project would be high quantity job creation, but up front investment in the permanent forest infrastructure would be repaid over the long term of highly productive operation. A large cadre of trained workers for forest management, a large expansion of agricultural operations, and a long term flow of export products would lift us from our current employment debacle.

    We see this as a public project that should appeal to all political strains, since it would create a backbone infrastructure that would set the stage for use of energy to continue functioning of our developed world without damage to the global environment.

    Implementing such a concept would require much detail in its actual design, but feasibility in general is not in question. This would be a massive federal project that must be handled by government, both in regard to international water negotiations and financial arrangements.

    Is there a political force that can handle such a project?

    ** The announced plan by the EPA is to require ‘best available technology’ and the recent report by them (Sept 2010) said ‘carbon’ capture would cost up to $95 per ton of CO2. Working this out in terms of the burden on the use of a ton of coal shows that the burden for use of a ton of Powder River Basin coal (half the element carbon by weight) will be about $180 per ton of that coal, and higher carbon coal would incur proportionately higher burden, up to around $320 per ton.

    *** President Hu said, “— we will energetically increase forest carbon — we will endeavor to increase forest coverage by 40 million hectares and forest stock volume by 1.3 billion cubic meters by 2020 from 2005 levels.” ( This was reported by Joe Romm at his ‘climateprogress’ web site. See – )

    [Response: OK, you’ve now repeated this mantra several times. As I and many others have mentioned, there are enormous potential ecological, hydrological, economic and social issues involved in such grandiose geo-engineering schemes, which you gloss over or ignore, most of which I highly doubt you are even aware of. The history of land and ecosystem “management” is littered with the residue of the unforseen consequences of similarly ill-conceived schemes which appeared, at the time, to be simple, “can’t fail” ideas. Ecosystems are exceedingly complex things that defy easy analysis or prediction, and make no mistake, you are talking about massive rearrangements to the earth system with almost entirely unknown consequences, logistical issues, feasibility questions etc. No more pie in the sky proposals sans detailed discussions of biophysical limits, system effects, costs, etc., supported by defensible reference to the scientific literature.–Jim]

  17. 167
    Patrick 027 says:

    Re 120, 153 HenryP –

    Absorption of solar radiation within the atmosphere would cool the surface, but if it occurs below the tropopause, it still brings heat below the tropopause – it would tend to reduce convection without much effect on surface temperature (on average). Absorption above the tropopause has a cooling effect, but the effect is reduced by the increased downward LW flux from the upper atmosphere that occurs in response to warming that is due to the solar heating there. Absorption of radiation that would otherwise have been reflected to space reduces albedo and thus results in greater solar heating.

    The surface and troposphere are generally coupled by convection that tends to maintain some relative temperature distribution, so radiatively forced warming or cooling at any vertical level below the tropopause tends to have an effect that is vertically spread out from the surface to the tropopause. Thus, surface and tropospheric temperatures tend to respond to changes in the net radiative flux (LW+SW) at the tropopause level (changes in the incoming and outgoing energy). The stratosphere responds to radiant heating or cooling of the stratosphere, which is the difference between the fluxes at the bottom and top of the stratosphere.

    The LW effect of CO2 dominates over the SW effect of CO2 by a relatively large margin – sorry I don’t know the numbers for CO2 offhand; there is a paper I know of which could help and I’ll try to find it.

  18. 168

    The background against which trees look good is provided by the EPA study at:

    Specifically on page 9 we find:

    exact paste————————

    Though CCS technologies exist, “scaling up” these existing processes and integrating them with coal-based power generation poses technical, economic, and regulatory challenges. In the electricity sector, estimates of the incremental costs of new coal-fired plants with CCS relative to new conventional coal-fired plants typically range from $60 to $95 per tonne of CO2 avoided (DOE, 2010a). Approximately 70–90 percent of that cost is associated with capture and compression. Some of this cost could be offset by the use of CO2 for EOR for which there is an existing market, but EOR options may not be available for many projects.

    end paste—————–

    The curious failure of this study is that the cost is in terms of tons of CO2, rather than tons of coal, so that on quick reading it might seem tolerable. (See footnote of my 4:15 comment.)

  19. 169
    David B. Benson says:


    In other settings these are called bypotheses, often with parameters to be adjusted for best fit to the data. That is, the data is treated as signal to be explained by the hypothesis plus random noise. Fairly obviously, a model with more parameters ought to give a better fit in trade for a more complex hypothesis, there being more parameters.

    To resolve this tension between fit and the complexity of the hypothesis, there are various information criteria that are used to determine a \best\ hypothesis. For example, the
    which penalizes parameters less than other popular information criteria.

    For the analysis of some time series, just this suffices to select the \least wrong\ (usually called \most informative\) model.

  20. 170
    John E. Pearson says:

    156 Maya said “Even a mathematical equation describing the behaviour of a block of wood sliding down an incline is a model”

    Of course it is, as is measuring the height of a column of mercury in a glass tube and calling the height “temperature” and then claiming that the length of the mercury column is related to what we perceive as “warmth” and also that that same thing, a length called “temperature”, is related to the distribution of speeds of “molecules” that make up what we call a “gas”. Concepts such as “molecules”, “temperature”, etc are all models and they work like gangbusters. Models are what we use to make sense of the data stream that we identify as “reality”. I suppose that most posters here think this is pedantic nonsense. In point of fact there is no way to interpret any experimental observations except within the context of already existing models. To complain that climate science generically relies on models is unreasonable. Questioning whether specific features of the models that we rely upon are adequate for specific tasks is what scientists do and is entirely reasonable.

  21. 171
    James says:

    an ideal place for my dumb question that vexes me, if anybody can offer words of wisdom thanks very much.
    Some 60% of produced CO2 is sequestrated by natural sinks
    The other 40% goes into the atmosphere where it is subject to a complex series of 1/2 lives with some 100 year average.
    This ratio is unchanged over recent decades

    How does any particular packet (or mole) of C)2 know it’s destined for the A team or the B team

    The only explanation I can dream up is that natural sink atmosphere is in equilibrium
    in which case either the natural sink is infinitely large or the ratio must change

    Have I missed something

  22. 172
    ccpo says:

    [Response: I agree with much of what you’re saying, but be very careful with conclusions on the topic of global effects of forests on the climate system. Hopefully we can do a post on the topic because people are clearly interested. In the mean time, everyone interested should definitely read this paper by Gordon Bonan, which has already been cited 168 times in ~ 2+ years.–Jim]

    Actually, I do apologize. I had in my head the thought, then forgot it as I typed, of mostly regrowing former old growth forests and replacing single trees in parks and such with food forests, which sequester a lot more biomass. I do recall, for example, that evidence points to a positive feedback, possibly due to reflectivity, from additional tree growth at high latitudes.

    Still, in the short term, people planting trees and food forests can only help. It won’t grow into a global mass planting until things are far more dire and is governmentally funded.


  23. 173
    Fred Moolten says:

    James (169) – Your question isn’t dumb. It’s perceptive. The 100 year average you quote is probably an underestimate (see #56), but it makes the point of a long interval needed for elevated CO2 concentrations to subside. The basic answer to your question is that the natural sink is not infinite, but it is very large (particularly the ocean sink), and so even a large input of CO2 into the atmosphere will change the ratio only slightly. Ultimately, however, the capacity of the ocean to absorb more CO2 diminishes, and so the airborne fraction will increase – a disturbing thought considering the consequences of rising CO2 based on the current fraction.

    Finally, over many thousands of years, eleatmospheric CO2

  24. 174
    David B. Benson says:

    John E. Pearson @168 — Well put.

    [Even reCAPTCHA agrees, delphically entoning “overtick comprehend”.]

  25. 175
    Fred Moolten says:

    James (169) – Your question is perceptive, not dumb. Natural sinks are not infinite, but the ocean sink is very large compared with the atmosphere, and so substantial elevations of atmospheric CO2 change the ratio only minimally in the short run. Over longer intervals, the airborne fraction will increase as sink capacity diminishes, exacerbating the greenhouse warming due to anthropogenic emissions. Ultimately, over hundreds of thousands of years (see #56), elevated CO2 levels, if unperturbed, return to baseline, accompanied by a return to pre-baseline rates at which oceanic CO2 (in the form of carbonates) exits the climate system into the Earth’s interior via subduction zones. This relieves the oceanic sink of the disequilibrium between uptake and removal of CO2, but it takes a very long time.

  26. 176
    TimTheToolMan says:

    Thank you all for your responses to my question regarding the implications of a significant model flaw. Some of the answers were very enlightening and I appreciate your time in considering this as you have.

  27. 177
    Damien says:

    Damien @ 111 – check the Skeptical Science link again, Kooiti Masuda @ 23 sums up the situation.

    Cheers, thanks for that.

  28. 178
    Hank Roberts says:

    > James … ratio is unchanged
    Citation needed.

    I suggest reading:

    “a decline in the efficiency of CO2 sinks on land and oceans in absorbing anthropogenic emissions.”

  29. 179
    Damien says:


    I’m not intending this to be published, but I’m not sure if Tex is working in the following:

    For example, I can see:

    F_{Top}= \Delta S + \Delta \lambda (G_0 - A_0) = \Delta S + {{0.5 \Delta \lambda S } \over { (1-0.5\lambda) }}

    I’m using Ubuntu 10.10 (Linux) with Firefox. It is also reproducible using Opera.

    Unfortunately, the comments on that thread are closed, so the closest I can get is this unforced variations thread.

    Thanks for the effort that everyone puts into the site.

    — Damien

    [Response: Nothing to do with your system, it is rather that latex is broken on our server. We should probably fix that. – gavin]

    [Response: Update: Hey! that was much easier than I thought. ;-) – gavin]

  30. 180
    Thomas says:

    120 Henry P. Part of your initial coment concerned the radiation path from the moon to the earth. So just in case you think extra CO2 has a significant shielding effect from lunar infrared, an estimate of the magnitude is useful. In visable light the full moon is roughly a million times dimmer than the sun (as seen from earth). IIRC astronomical magnitudes are -26.7 and -12.5, which would yield a ration of: 10.**(.4*14.2). Since lunar albedo is under ten percent, we can bump up the lunar IR luminosity by roughly 10 times, but that still puts it at roughly a hundred thousand times weeker than solar flux. So lunar radiation to the earth is a tiny overall effect.

    137 Last I had heard the faint young sun paradox is still not easy to solve. If we assume doubling of CO2 is roughly similar to a 1percent increase in solar luminosity (maybe its more like 2% -but that doesn’t affect the argument much), then we would need approx 30doublings of CO2, which is far beyond anything reasonable. Now greenhouse gases work better in combination, add species with non overlapping absorption bands and it is a lot easier to get a given degree of warming. So we probably had a lot of methane, and perhaps SO2 as well. But I don’t think we have a good handle on the composition of the early atmosphere. But it takes a lot of greenhouse effect to overcome the faint young sun.

    169: You were questioning the stability of the portion of anthropogenic CO2 that is retained in the atmosphere versus absorbed in non atmospheric reservoirs. Do the following thought experiment:
    Atmosphere, plus a linear by relatively small reservoir, which equilibrates quickly. The total CO2 should increase proportionately in both reservoirs (thats what I meant by linear reservoir total sequestered CO2 is proportional to atmospheric concentration). So small reservoirs with short cycle times would tend towards the observed fact.

  31. 181
    Patrick 027 says:

    Re HenryP –

    Collins et al:
    Radiative forcing by well-mixed greenhouse gases:
    Estimates from climate models in the
    Intergovernmental Panel on Climate Change
    (IPCC) Fourth Assessment Report (AR4)
    a version also found here:

    SW and LW forcings are calculated by LBL codes (and compared to values calculated in AOGCMs)

    But not for global average conditions!

    For conditions:
    clear sky,
    climatological midlatitude summer (MLS) atmospheric profile (temperature, ozone, water vapor – except when water vapor change is the ‘forcing’ being analyzed)

    for SW fluxes, surface is a Lambertian (diffuse) reflector with wavelength-independent albedo 0.1; at TOM, incident solar radiation is 1360 W/m2 (this doesn’t include the 6.33 W/m2 flux found at wavelengths longer than 5 microns) at a zenith angle of 53 degrees (Which is then 818 W/m2, and about 2.41 times the global average (aside from the small fraction of longer-wavelength solar flux not included) or 2.4 times the global average whole-spectrum incident solar flux.

    for LW fluxes, the surface is approximated as has an emissivity of 1 and a temperature of 294 K.

    spectral interval of 4 to 5 mm is contained in both shortwave
    and longwave calculations, but it is not counted twice since
    the shortwave codes omit thermal emission and the longwave
    codes omit solar flux.
    ” (paragraph 15)

    from Tables 8 and 9, mean values of the LBL calculations:
    instaneous forcings (decrease in net upward flux/area before any climate response, W/m2):
    column 1: surface
    column 2: 200 mb (near tropopause level**; mb = hPa)
    column 3: TOM (top of model, which I assume is also effectively TOA, top of atmosphere)
    values derived from first three columns:
    column 4: TOM-200 hPa (forcing on the stratosphere, if tropopause is at 200 mb),
    column 5: adjusted 200 hPa forcing assuming 5/11*** of the stratospheric forcing is transfered to the 200 hPa flux)

    doubling CO2 from 287 to 574 ppm
    LW _ _ _ _ _ _ : __ 1.64 _|__ 5.48 _|__ 2.80 _|_ -2.68 _|__ 4.26
    SW _ _ _ _ _ _ : _ -0.96 _|_ -0.77 _|__ 0.12 _|__ 0.89 _|_ -0.37
    Total _ _ _ _ _: __ 0.68 _|__ 4.71 _|__ 2.92 _|_ -1.79 _|__ 3.90

    SW / LW , % __ : _ -58.5 _|_ -14.1 _|_ _ 4.3 _|_ -33.2 _|__ -8.6
    SW / Total , % :_ -141.2 _|_ -16.3 _|_ _ 4.1 _|_ -49.7 _|__ -9.4

    increasing H2O concentrations by 20 % (considering the water vapor feedback)
    LW _ _ _ _ _ _ : _ 11.52 _|__ 4.57 _|__ 3.78 _|_ -0.79 _|__ 4.21
    SW _ _ _ _ _ _ : _ -5.87 _|__ 0.51 _|__ 0.75 _|__ 0.24 _|__ 0.62
    Total _ _ _ _ _: __ 5.65 _|__ 5.08 _|__ 4.53 _|_ -0.55 _|__ 4.83

    SW / LW , % __ : _ -51.0 _|__ 11.2 _|__ 19.8 _|_ -30.4 _|__ 14.7
    SW / Total , % :_ -103.9 _|__ 10.0 _|__ 16.6 _|_ -43.6 _|__ 12.8

    **”The quantities requested from each participating
    group include (1) net shortwave and longwave clear-sky
    flux at the top of the model, (2) net shortwave and longwave
    clear-sky flux at 200 hPa, (3) net shortwave and longwave
    clear-sky flux at the surface, and (4) (optionally) net
    shortwave and longwave clear-sky fluxes at each layer
    interface in the profile. The reason for performing calculations
    at 200 hPa rather than the tropopause is to insure
    consistency with the radiative quantities requested as part of
    the climate change simulations. Since not all modeling
    groups are prepared to compute fluxes at a time-evolving
    tropopause, the Working Group on Coupled Modeling
    (WGCM) of the World Climate Research Programme
    (WCRP) and the IPCC have requested fluxes at a surrogate
    for the tropopause at the 200 hPa pressure surface. The
    precise choice of tropopause can affect forcings by up to
    10% [Myhre and Stordal, 1997].
    ” (paragraph 13)

    *** – that’s an approximation that I’m using with some justification but absent detailed knowledge (educated approximate guess)(to the extent that most of the emission leaving the stratosphere is at wavelengths where the stratosphere is optically thin, a first approximation can be made that 1/2 of the change in stratospheric emission is in upward TOM flux and the other half is in downward tropopause-level flux; both greenhouse gas-induced stratospheric cooling and SW heating changes should tend to be larger in the upper stratosphere than in the lower stratosphere, while the same temperature change has a greater effect on radiant fluxes when the initial temperature is warmer; thus, for Earth’s stratosphere, the general tendency should be for the tropopause level flux to change less than the TOA flux for stratospheric adjustment. The total emission from the stratosphere leaving the stratosphere now is divided up with about 5/11 going downward and about 6/11 up to space (Hartmann, “Global Physical Climatology”, 1994) – I don’t expect the same proportion to apply to stratospheric adjustment, but I start there in the absence (on my part) of more work/info).

    (refering to the effect of stratospheric adjustment to tropopause-level forcing (haven’t checked the source but I’d assume this is for global average forcings):
    The effects of adjustment on forcing are approximately -2% for CH4, -4% for N2O, +5% for CFC-11, +8% for CFC-12, and -13% for CO2 [IPCC, 1995; Hansen et al., 1997]. (paragraph 11))

  32. 182
    Hank Roberts says:

    “Forest restoration offers expensive … hopeful and depressing lessons ….”
    “… ground rules intended to return forests to the densities that prevailed perhaps 100 years ago.
    In many cases, that would involve reducing tree densities from 600 to 1,000 per acre to about 50 per acre.”

  33. 183
    William P says:

    Much of the discussion on climate blogs is about things like adequacy of models, outcomes of certain chemical balances in the atmosphere, characteristics of CO2 in the atmosphere and oceans, etc.

    I have tried to get an answer to a basic question: Is anybody thinking or planning for a strategy – individual or national – if every effort at reducing green house gas fails (as seems likely I am sorry to say) and we go into that uncharted place where temperature rises to impact man and nations in a big and serious way.

    Such as significant and perhaps sudden rise of sea levels due to large ice masses sliding off Greenland and/or Antarctica, or multiple and larger episodes worldwide of what we saw in Russia this summer with extreme heat, fires and loss of 25% of the wheat crop.

    Is contingency planning in order for those probable events? Some suggest large impacts of global warming are far off. My gut feeling based on what have proved overly conservative projections of sources like the IPCC is that big impacts of warming will come sooner – perhaps much sooner than we think. To my knowledge we are completely unprepared if large impacts set in suddenly. A significant onset of such events as mentioned above could bring on another related impact. As people and nations feel impacts, industrial activity such as generation of electricity could slow significantly if plants shut down. We had a shut down of air traffic on 9-11 and that small change – fewer planes in our skies – resulted in an immediate 1 degree C rise in temperature worldwide as particulate matter fell to earth.

    Does anyone know of significant planning going on for events such as above?

    Thank you for your assistance.

  34. 184
    William P says:

    ccpo says (172) “Still, in the short term, people planting trees and food forests can only help. It won’t grow into a global mass planting until things are far more dire and is governmentally funded.”

    When it becomes “dire” won’t it be too hot for “food crops”? As in Russia this summer.

  35. 185
    CM says:

    HenryP #120,
    re: effect of absorption of incoming near-infrared by CO2,
    and further to Patrick 027’s conceptually helpful discussion at #167,

    Browsing a bit, I find references saying near-infrared absorption of CO2 is a significant heat source in the mesosphere. If I understand correctly, the dominant effect on the mesosphere of increasing CO2 is to cool it through increased emission at 15 µm. This mesospheric cooling will be counteracted to some degree by increasing absorption in the near-infrared, but according to Fomichev et al. 2004, not significantly so for a doubling of CO2 at the surface (Fomichev et al. 2004, doi:10.1029/2004GL020324).

    As a layman, I can’t assess this finding. And despite Patrick’s helpful discussion above, I’m confused as to what, if anything, this might mean for energy flux and temperature on the surface. But if increased NIR absorption by increased CO2 does not significantly offset increased greenhouse cooling in the mesosphere, where CO2 NIR absorption is an important term, is there any reason to expect it to significantly offset greenhouse warming in the troposphere?

  36. 186

    HenryP 153: I am looking for answers to two simple questions, you advise me to buy two books.If you have the answers in the right dimensions, why don’t you give it. If you admit that you cannot provide me with the answers, then you have to feel very bad (if you are an expert on CO2).

    BPL: I didn’t “give you” the answers because the answers are not simple. If you want to understand this stuff you’ll have to do some work. Sorry about that.

  37. 187
    The Ville says:

    “I dont want to dis the models too badly. As a tool they’re great. Its just that they’ve now BECOME the science and that is at best too risky to building climate science upon and at worst potentially just plain wrong.”

    Even as a non-scientist I know that to be wrong.
    Some people put an emphasis on the models because they are a tool that tries to predict based on the ‘science’ programmed into them. There is a fascination for prediction.

    There are just to many other areas of science (and ongoing observations) that agree with the trajectory the models predict. Even if you removed models, people would be analysing observations and making probably even more wild predictions!

    Which is a thought. Models might actually be a moderating influence on predictions.

    BTW I like the word trajectory, I think it is a useful analogy when describing a general direction that is predictable within a margin of error.

  38. 188
    Ray Ladbury says:

    Tim the Tool Man,

    Believe it or not, folks here are usually happy to try and help answer a polite question (particularly on an open thread–BTW Thanks, Gavin, Jim et al.).

    I think you may be suffering from an illusion that is common among nonscientists and even among some scientiists–namely that the purpose of a model is to yield accurate answers. This isn’t really the case. If we put in a complicated enough model, we can always match a data set–and thats how you get the Ptolemaic universe, astrology and homeopathy.

    Rather, the purpose of a model is to yield insight into the phenomenon under study. In general, we know a model is successful if it reproduces the behaviour of the system–that’s the Goodness of Fit. However, even a model that fails to yield accurate agreement may be successful at helping us understand the system.

    George Box said, “All models are wrong. Some models are useful.”

    It is also important to understand the difference between statistical models (essentially data fitting) and dynamical or physical models. The former are prone to overfitting, so we have to have tools to prevent this (e.g. various information criteria). The latter are very unlikely to yield accurate results if we have incorrect physics. However, dynamical models are only possible when you understand the system being modeled very well. The successes of GCM demonstrate that we understand climate sufficiently well to reproduce the global, long-term behavior of the system. We still have a way to go before we understand the system on short timescales or regionally. Hope this helps.

  39. 189
    Anonymous Coward says:

    William P,
    Organizations with planning authority largely see global contingencies as someone else’s problem. There is no global authority and national and regional authorities are stuck in a nationalist morass. This is not a problem specific to climate issues.
    States such as the Netherlands which are particularily vulnerable are more prone to responsible planning. I recommend you consult the Dutch general planning report aimed at the public.
    Organizations in chage of “national security” have also been more proactive than others but their focus is of course not on constructive solutions.
    Of particular concern are the thorny political problems associated with mass migration which is pretty much the only way that climate catastrophes could be adapted to without loss of life on a truely massive scale (assuming current technology and resources). It would take a long time to establish an acceptable framework which would allow migration on an unprecedented scale. Fortunately there is no indication that we are facing imminent climate catastrophes. But planning needs to start yesterday.

  40. 190
    Hank Roberts says:

    Aside for Jim — when you get a persistent commenter like TTTM, Google the name +climate.

    You’ll find he’s, how to put it politely, often popping up in ways that get used by others to point out how the climatologists don’t treat him respectfully. Kind of an ambulatory strawman.

    JC used him that way last week:

    Of course anyone can pretend to be anyone else, “TTTM” could just be a handy label used to set up this kind of, er, intervention.

    It’s hard to talk about the tactics used to set up bloggers for trouble. MT did a good thoughtful commentary a few years back about how people will set up situations with considerable effort just to blow them up intentionally.

    Just sayin’ it’s always worth the effort, when someone starts to get under your skin, to suspect intent and involvement in a group effort.

    Only those who can see IP addresses know for sure if “TTTM” or anyone else is even coming from the same location each time the pseudonym is used in various places.

  41. 191
    Hank Roberts says:

    Further aside — on the same JC thread, one of the authors comments:

    “…. Last year, April, Daniel Murdiyarso (a climate scientist) and myself (a forest biologist) published an overview of the basic ideas for a less-technical audience “How forests attract rain: an examination of a new hypothesis” in Bioscience. That got some media coverage: you may have seen some of it: e.g. Mongabay, New Scientist and Scientific American (please google). I’m happy to share the PDF if anyone wants it. The point is that many of the wider implications (including monsoons) are considered in a reasonably non-technical manner for those of you who might be interested in that….”

    I’d recommend focusing on that comment and those by the other published scientists — and not wasting more effort on the TTTM distraction, which was a real waste of time both in this thread and in the one over at JC’s blog and utterly derailed three different blogs where there was some beginning of good discussion of the water vapor/humidity issues.

  42. 192
    Hank Roberts says:

    And here it is:
    April 2009, Vol. 59, No. 4, Pages 341–347 , DOI 10.1525/bio.2009.59.4.12
    Posted online on April 3, 2009.

    How Forests Attract Rain: An Examination of a New Hypothesis

    Douglas Sheil‌1,2, Daniel Murdiyarso‌2
    1 Institute of Tropical Forest Conservation, Mbarara University of Science and Technology, in Kabale, Uganda. E-mail: or
    2 Center for International Forestry Research in Jakarta, Indonesia.

    A new hypothesis suggests that forest cover plays a much greater role in determining rainfall than previously recognized. It explains how forested regions generate large-scale flows in atmospheric water vapor. Under this hypothesis, high rainfall occurs in continental interiors such as the Amazon and Congo river basins only because of near-continuous forest cover from interior to coast. The underlying mechanism emphasizes the role of evaporation and condensation in generating atmospheric pressure differences, and accounts for several phenomena neglected by existing models. It suggests that even localized forest loss can sometimes flip a wet continent to arid conditions. If it survives scrutiny, this hypothesis will transform how we view forest loss, climate change, hydrology, and environmental services. It offers new lines of investigation in macroecology and landscape ecology, hydrology, forest restoration, and paleoclimates. It also provides a compelling new motivation for forest conservation.”

    This reminds me of the way redwoods in N. Ca. are known to harvest water by condensing it from the air.

  43. 193
    TimTheToolMan says:

    @Ray Ladbury : “I think you may be suffering from an illusion that is common among nonscientists and even among some scientiists–namely that the purpose of a model is to yield accurate answers.”

    Perhaps you should read my post 117.

    I dont think its going to be feasible or healthy to discuss my question in this thread/forum anymore for fairly obvious reasons.

  44. 194
    Hank Roberts says:

    Consistent with ‘forests attract rain’ — this:
    “A new study in Biological Conservation has shown that edge forests and forest patches are more vulnerable to burning because they are drier than intact forests. Using eight years of satellite imagery over East Amazonia ….”

  45. 195
    Ray Ladbury says:

    Tim the Tool Man,
    I think the thing you need to realize is that in science you have to ask very precise questions if you want to get reasonable answers. “Something wrong” is not precise. You can do one of two things with the criticism you have gotten here (which you must admit was mostly constructive and not personal): You can run off and whine about being misunderstood on Climate Fraudit or WTF or you can try to reformulate your question so that you and we can learn something of value from it. Remember, that much of the physics in the models is very tightly constrained. That is why most of us are having trouble visualizing exactly what you are getting at–what sort of “something” you mean. Presumbably, you have the same trouble, as you have been unable to refine your comment.

    Yes, climate is complicated. Yes, the models are simplifications. However, remember that the goal of the models is to elucidate the factors that are important and so maximize predictive power. They do that quite well.

  46. 196
    John E. Pearson says:

    179 Gavin!! You are awesome!


  47. 197
    meteor says:


    I repeat my question:

    I read “atmospheric CO2: principal knob governing earth’s temperature”

    In your “experience” you are zeroing all the non condensable gases and all the aerosols.

    The aerosols have a GH effect but they have also an effect on the clouds
    So what is the influence of aerosols on the clouds in your model?

    [Response: In the simulation described in the paper, only GHGs were zeroed (not aerosols). This configuration didn’t have an a priori calculation of the aerosol indirect effects so nothing would have happened anyway. We could re-run it with the configuration including that, but you would have to think carefully about what you were testing – no aerosol emissions anywhere? no land emissions? what about sea salt? dust? etc. – gavin]

  48. 198
    Hank Roberts says:

    TTTM tried to raise a valid question, in a way so crosspatch that nobody managed to respond and it’s still not clear if TTTM understands the question.

    “If you have a choice between a hypothetical situation and a real one, choose the real one.” — Joan Baez

    For a real one, see the JC thread and/or the JeffID thread where Gavin has participated.


  49. 199
    IqRS says:

    Perhaps you could refer to “Data Rescue At Home”
    Swiss climate scientist want to digitize climate data with the help of volunteers!

  50. 200
    CM says:

    re: HenryP’s question
    — okay, scratch my #185, looks like Patrick has the goods at #180.

    re: #179 (LaTeX math)
    Oh, cool! I always thought RC just weren’t interested in supporting it. Turns out you just had to ask…