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How not to attribute climate change

Filed under: — rasmus @ 10 October 2006

In an earlier post, we discussed a review article by Frohlich et al. on solar activity and its relationship with our climate. We thought that paper was quite sound. This September saw a new article in the Geophysical Research Letters with the title «Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record» by Scafetta & West (henceforth referred to as SW). This article has now been cited by US Senator James Inhofe in a senate hearing that took place on 25 September 2006 . SW find that solar forcing accounts for ~50% of 20C warming, but this conclusion relies on some rather primitive correlations and is sensitive to assumptions (see recent post by Gavin on attribution). We said before that peer review is a necessary but not sufficient condition. So what wrong with it…?

Recent Climate Change attribution (from Wikipedia)

The greatest flaw, I think, lies in how their novel scale-by-scale transfer sensitivity model (they call it “SbS-TCSM”) is constructed. Coefficients, that they call transfer functions, are estimated by taking the difference between the mean temperature of the 18th and 17th centuries, and then dividing this by the difference in the averages of the total solar irradiances for the corresponding centuries. Thus:

Z = [ T(18th C.) – T(17th C.) ] / [ I(18th C.) – I(17th C.) ]

Here T(.) is the temperature average for the century while I(.) is the irradiance average. If the two terms, I(18th C.) & I(17th C.), in the denominator have very similar values, then the problem is ill-conditioned: small variations in the input values lead to large changes in the answers; which implies very large
error bounds. In my physics undergraduate course, we learned that one should stay away from analyses based on the difference between two large but almost equal numbers, especially when their accuracy is not exceptional. And using differences of two large and similar figures in a denominator is asking for trouble.

So when SW repeated the exercise for the differences between the 19th and 17th centuries, and for three different estimates of the total solar irradiance, the results gave a wide range of different values for the transfer functions: from 0.20 to 0.57! The problem is really that SW assume that all climatic fluctuations in the 17th to the 19th centuries to solar activity, and hence neglect factors (natural forcings) such as landscape changes (that the North America and Europe underwent large-scale de-forestation), volcanism (see IPCC TAR Fig 6-8), and internal variations due to chaotic dynamics. It is, however, possible to select two intervals over which the average total solar irradiance is the same but not so for the temperature. When the difference in the denominator of their equation is small (the changes in the total solar irradiance are small), then the model blows up because other factors also affect the temperature (i.e. the difference in temperature is not zero). Thus their model is likely to exaggerate the importance the solar activity.

To show that the equation is close to blowing up (being “ill-defined”) their exercise can be repeated for the differences between 19th and 18th centuries (which was not done in the SW paper). A simple calculation for the 19th and 18th centuries is quickly and easily done using results from their table 1 and figures 1-2: A back-of-the envelope calculation based on the 19th and 18th centuries suggests that the transfer functions now would yield an increase of almost 1K for the period 1900-2000, most of which should have been realized by 1980! One problem seems to be that now the reconstruction based on solar activity increases faster than the actual temperature proxy. That would be difficult to explain physically (without invoking a negative forcing).

Modified SW2006b figure 2

The SW paper does discuss effects of changes in land-use, but only to argue that the recently observed warming in the Northern Hemisphere may be over-estimated due to e.g. heat-island effects. SW fails to mention effects that may counter-act warming trends, such as irrigation, better shielding of the thermometers, and increased aerosol loadings, in addition to forgetting the fact that forests were cut down on a large scale in both Europe and North America in the earlier centuries. Another weakness is that the SW analysis relies on just one paleoclimatic temperature reconstruction, but using other reconstructions is likely to yield other results.

Looking at the SW curves in more detail (their Fig. 2), one of the most pronounced changes in their solar-based temperature predictions is a cooling at the beginning of the record (before 1650), but a corresponding drop is not seen in the temperature curve before 1650. It is of roughly similar magnitude as the increase between 1900 and 1950, but it is not discussed in the paper. As in their earlier papers, the solar-based reconstructions are not in phase with the proxy data. However, SW argue that by using different data for the solar irradiance, the peaks in 1940 (SW claim it is in 1950) and 1960 would be in better agreement. So why not show it then? Why use lesser data?

The curves in Figure 2 (Fig. 2 here shows the essential details of their figure) of the SW paper suggests that their reconstruction increases from -0.4 to 0K between 1900 and 2000, whereas the the proxy data for the temperature from Moberg et al. (2005) changes from -0.4 to more than +0.6K (by rough eye-balling). One statement made both in the abstract of the SW paper and the Discussion and Conclusions (and cited in the senate hearing) is that «the sun might have contributed to approximately 50% of the total global surface since 1900 [Scafetta and West, 2006 – an earlier paper this year])». But the figure in the SW paper would suggest at the most 40%! So why quote another figure? The older Scafetta and West (2006) paper which they cite is discussed here (also published in Geophysical Research Letters), and I’m not convinced that the figures from that paper are correct either.

There are some reasons to think that solar activity may have played some role in the past (at least before 1940), but I must admit, I’m far from convinced by this paper because of the method adopted. It is no coincidende why regression is a more widely used approach, especially in cases where many factors may play a role. The proper way to address this question, I think, would be to identify all the physical relationships, and if possible set up the equation with right dimensions and with all appropriate non-linear terms, and then apply a regression analysis (eg. used in “finger print” methods). Last week, we discussed the importance of a physical model in making attributions because statistical correlations are incapable of distinguishing between forcings with similar trends. Here is an example of a paper that has exactly that problem.

There is also a new paper out on the relationship between galactic cosmic rays and low clouds by Svensmark. We will write a post on this paper shortly.

210 Responses to “How not to attribute climate change”

  1. 151

    Re Dave Cooke’s #146,

    You have raised some interesting points there which I am not competent to answer but I will give you my thoughts.

    The strosphere is warmed by the absorption by ozone of ultra violet rays, and so forms a cap (inversion layer) on the tropsphere. When the atmosphere became oxygenated by the evolution of photosynthetic life and the ozone layer formed, it seems that there may have been a Snowball Earth event, or at least severe climatic disturbance.

    There are gravity waves in the atmosphere produced by solar heating and the gravitaional effects of both moon and sun, but because the diurnal heating effect is so strong, and the surface of the earth is so uneven, the gravitational effects are difficult to identify.

    These tides, the stratospheric quasi-biennial oscillation (QBO) and the Arctic Oscillation are all probably linked. This may result in biennial outflows of cold fresh water from the Arctic, which account for the ocean surface cooling you mention. Alternatively, stronger winds over the mid latitudes may have increased evaporation and so lowered temperatures.

    Since most of the science is done in the USA there is a tendencey to believe that conditions in North America apply throughout the world. The US standard atmosphere is treated as being correct globally, and IMHO this is one reason that the models do not work for the tropical lapse rate.

    There is a huge amount of work going on by unsung scientists, and eventually the answer to all these questions will become clear. But will that happen before disaster strikes?

  2. 152
    Steve Hemphill says:

    Re #142

    First, it appears no one has a good handle on how much convection is increasing, therefore realistically on how much albedo is increasing due to it.

    Second, energy in vs. energy out of the system can hardly balance until we have a better handle on the circulation of the ocean (over 95% of the heat capacity of Earth) and its rate of heat uptake. E.g. El Nino. So no, energy conservation is not yet being realistically addressed either.

  3. 153

    Re Wayne’s #147,

    James Annan seems pretty sure that he is right with his 3K for x2 CO2. If he is right, then the models that claim 1.5K are out by a factor of 2, and those that claim 4.5K are out by 50%. You don’t seem to have been fooled by those scientists who claim infallibility :-)

    Related to your arguments is an error in the models where the surface air temperature is the same as the surface temperature. If that were true, how come we get gound frosts and air frosts at different temperatures?

    You are right that taking an average at 700 mb might miss a temperture change elsewhere, but the problem is not whether the atmosphere as a whole is warming. If the air in the boundary layer is warming and the statosphere is cooling so that the total heat in the atmosphere stays the same, then that is no comfort for us who are living on the surface!

    In fact, since solar radiation has not changed, then there is no need for outgoing radiation to space from the atmosphere to change if it is to remain in balance. My theory is that increasing CO2 will raise the temperature within the boundary layer. That temperature change will be considerable amplified by the greenhouse effect of water vapour due to the greater humidity at the higher temperature. The condensation level at the top of the boundary layer will prevent this increased humidity reaching further up into the atmosphere, because it will be rained out from the clouds at the condensation level. Although this is an over simplified model, I believe it is closer to the truth than the current idea that a change in the height of layer of atmosphere near the tropopause, around 100 mb, can affect the temperature of the planet at the 1000 mb level. Gavin, how do you achieve this x10 amplification of heat?

  4. 154
    L. David Cooke says:

    Mr. McDonald’s #153

    I am curious that you would seem to indicate a stable boundary layer. I have been reviewing the latest lidar and microwave radar data and have not found a specifc boundary altitude. It also appears that the transition zone for the condensation level seems to vary greatly. I do not believe it can be as simple as you appear to want to portray. Hence my earlier questions.

    Examples can be found under the following links. Note, the warning associated with the CloudSat, this apparently is a recent change to apparently limit the unauthorized distribution. In the meantime, the Calipso data is supposed to range between 0 and 30 km, there are recent examples in the SH temperal zone below the ITCZ of cloud/water vapor structures well above both the 5-7km normal condensation level, above the 15-17km normal Thunderstorm peak and into the 20-26km region of the upper stratosphere. The interesting thing in the latest images is that the stratospheric clouds do not appear to be related to Thunderstorms, I wonder if this is due to uplift in the region of the Andes? Anyway, I thought this may be of interest to you in your further research as you work towards developing your theory.

    Reference URLs

    If you can get access by being a verifiable card carring member of the scientific community at large you might be able to access the data found here.

    Dave Cooke

  5. 155
    L. David Cooke says:

    Regarding the earlier comment about the link for cloudsat. Disregard, I found that a NASA cloudsat link I had tried to execute prior had apparently locked up my browsers java console. It appears the the colostate code requires you to visit the site home page first then if you properly move from to everthing works fine. If you attempt to go directly to the dpcstatusQL.php site the code will hang.

    Dave Cooke

  6. 156
    Hank Roberts says:

    On attribution, it seems both extremes of the hurricane debate have forgotten Dr. Hansen’s prediction early this year that an El Nino would develop, as it has done.

    Snippet from a recent article on a recent hurricane conference argument (thanks to a link found at Coby Beck’s ‘Things Ill-Considered’ page, link for that in the right hand column),1299,DRMN_15_5094006,00.html

    “…During a break, Trenberth said the milder 2006 season was due largely to an unexpected Pacific El Niño that suppressed hurricanes in the Atlantic.

    Natural climate variability – including the periodic swings between El Niño and La Niña conditions in the Pacific – will sometimes overshadow global warming’s influence on hurricanes, Trenberth said.

    “Global warming is still there,” he said. “But this year, natural variability, especially El Niño, overwhelmed the contribution from global warming.”

    Roger Peilke Jr. last spring made much of a draft circulated by Dr. Hansen with an El Nino prediction. Unexpected? Natural variability? Attribution? I dunno.

  7. 157

    Thanks for those links Dave. They tend to confirm what you wrote – it is more complicated than I described, but I was aware of that.

    In fact most of the the diagrams there tend to show a line of clouds close to the ground. This line will have its base at the condensation level, which is the theoretical height at which relative humidity reaches 100%. In theory above that height the humidity remains at 100%, and so the greenhouse effect from water vapour in the region above the condensation level will not change.

    This is of course a simplification, but from ‘your’ diagrams it does not seem as if the condensation level is often breached by much, and the tropopause is breached even less. Of course the scheme I described ignores clouds, but then the Manabe and Wetherald (1967) scheme ignored clouds too.

    I am surprised to hear that there are clouds in the upper stratosphere. As I understand it that region is very dry. But the air does rise in the polar summer and travel via the stratosphere to the other pole where it subsides. If the Arctic ice is melting and more water vapour is rising into the stratosphere from there, then that might account for the clouds you are seeing, although they should soon start travelling north again.

    But I am a bit out of my depth here, or should I say it is going over my head!

  8. 158
    Tom Fiddaman says:

    Re 134

    I think by inadvertently choosing a bad analogy I have exposed the problem with your assumptions. The sluice gates at the top of a dam are highly nonlinear. If the lake level is 1″ below the sluice gate edge, outflow=zero. If the water level rises a foot, the outflow becomes very large. That’s a very strong negative feedback, hence the water level tends to remain very constant near the top.

    The temperature of the earth doesn’t work that way. There is no magic nonlinearity that causes convection to take off the moment temperature exceeds 289k. The local linearity of temperature can be described as deltaT=deltaR/lambda where deltaR is the change in forcing and lambda is radiative damping. Lambda is really a summary of a bunch of feedbacks, including radiation and convection but also clouds and water vapor. You can argue about lambda, which in a sense is what the whole debate is about, but the evidence just isn’t consistent with an overwhelming convection term.

    A better water analogy is a sink. Turn on the taps, then vary the drain opening, and you can get a wide range of equilibrium water levels without violating conservation of matter.

    Before you accuse GCMs of neglecting convection and conduction, you might try Google. They include both. A lot of convection is sub-grid-scale and thus must be parameterized, but there are also large-scale circulations that are directly simulated. Either way, convection is a feedback not a constant. I’m sure the models wouldn’t work without it. Conduction is mostly a surface phenomenon (i.e. at atmosphere interface with ocean, ice, etc.) and it is also accounted for.

  9. 159

    #157, Alastair, I am not keen on Tropopause heights because they cause a warming below, it is rather
    tropopause heights are higher because it is warmer below, there is also tropopause inversions triggered by higher Ozone concentrations, at the point where the tropopause starts you will invariably find the beginning of much higher ozone concentrations.

    Sorry about my common usage of surface temperatures,
    I should have written SAT’s. GT’s are second to none in meaning, but they do not correctly measure the warming of our atmosphere because they are taken at various heights all over the world. SAT GT’s have meaning only when comparing with previous years. They demonstrate a glimpse of a more complex warming of the atmosphere as a whole. Consider a measurement of GT’s as with a 6 Km
    long thermometer bullb fixed vertically just above ground at a stationnary geographic point. The temperature read from this thermometer over time will give a rate of Global Warming much more accurate than any other method. Snce we don’t have 6 Km long thermometers, other ways of measuring atmospheric temperatures have to be devised (perhaps there are a few already in place).

    James Annan estimate seems too low, only because the true rate , as you have written , has been underestimated. Unless Annan’s numbers are a SAT value while the models project a greater warming above a stephenson screen….

  10. 160
    L. David Cooke says:

    RE# 157

    Hey Alastair;

    I am afraid the theory of saturation above the condensation level you refer to may not be the case. It appears that the condensation has a tendency to remove the water vapor from the air as it condenses on Condensation Nuclei, the result is the air above the condensation layer is normally very dry.

    That is one of the reasons that clouds get ignored as they generally are not widespread or dense enough to be considered to have a significant impact on incoming solar radiant energy. Recent NASA programs such as the SAGE, TRMM, COSMIC, Calipso and Cloudsat have been engaged to research the effects they might have. Both in the polar and the ITCZ regions. (Where Calipso seems very useful in demonstrating the distribution of water vapor and its reflectivity value (Hence the association with temperature.) The CloudSat seems to be more valuable in defining the temperature gradiants along with vapor densities.)

    I did have one question though, you seem to mention the apparent oceanic oscillations such as the NAO or the ENSO or PDO. I am concerned that many seem to use these phenomenon to define characteristics of patterns. It would seem that defining the root source of these oscillations would be a better move as the description of the process may better describe processes that make up the earth atmosphere. Have you seen anything yet in print that describes the source and the drivers of these patterns?

    Dave Cooke

  11. 161
    Steve Hemphill says:

    Re #158:
    “There is no magic nonlinearity that causes convection to take off the moment temperature exceeds (whatever)”.

    The point is that if there is *any* CO2 in the atmosphere there will be convection.

    Your point of drains vs. weirs is okay, with similar restrictions. The original weir example had widths narrow enough and heights of flow such that all were flowing at the same time. Your drains need to be at differing elevations and of differing orifice sizes, but always submerged. More complex mathematically but perhaps closer to reality (perhaps – needs more thought).

  12. 162
    John Dodds says:

    Re: Comment by Hank Roberts – 28 Oct 2006 @ 2:55 am (#137): in response to my 26 Oct 2006 @ 10:07 am (#126):
    Hank (& Gavin)
    I did the GCM math a year or so ago and I agree that your simplified explanation adequately describes the current models of global warming, with clarifications. One is that the mechanism for the GHG warming is that the radiated energy from the air is absorbed by the GHGs to heat the GHG molecule to 900+ degrees, then the energy is released within microseconds and a few centimeters back to the air by collisions with the air, to return the air & GHGs to equilibrium temperature. (ie the GHGs do NOT “TRAP” the energy like greenhouse glass does). But by adding extra GHGs, there are MORE absorptions, and the energy is resident in the GHGs for more microseconds, which raises the time that the energy is resident in the air during its transit to space, thus causing the GHG global warming.
    I agree that the “decrease in energy-out ” is the source of the GHG global warming energy, AS DEFINED in the GCMs.

    HOWEVER, when you apply the laws of physics to the new end state, ie globe warmed by a few degrees by GHGs, you get a situation where the new Wiens law value (higher driving temperature gives hotter energy spectrum out) and the new Stefan-Boltzmann value, ( ie HIGHER energy out ) disagree with the physical situation that the model REQUIRES – ie energy out =99.98 units which is LOWER. BUT, the energy-IN is still 100, or actually raised a tiny bit by the added solar. IT DOES NOT MAKE SENSE. The math does not add up. The GCMs global model FAILS to comply with the Laws of Physics. It is not modeling reality. Any discussion about not being at equilibrium yet (the usual response) , fails to notice that on a daily basis the temperature varies by 10-15 degrees and that these changes will force the ground/atmosphere to get to equilibrium within a day or two. You also get a new Ideal Gas law, where the physical change in density which is trivial (substitute 390 ppm of CO2 for O2), results in a temperature than has a trivial change, BUT by the model we are a few degrees hotter. AGAIN the GCMs are describing a model world where it does not now comply with the laws of physics. Either the GCMs are right or the Laws of Physics are right.

    One possible way to fix this model failure is to account for the increased vertical flow of convection and conduction caused by the radiative GHG induced global warming, which apparently was, I assume, not adequately included in the GCMs. I have never seen any numbers for Convective feedback! ie The hotter air from GHG warming or forcing causes the total air (including the GHGs!) and electrons to rise faster. Hot air rises. Hotter air rises faster! The increased velocity of the air rising, reduces the time that the energy is resident in the air. which reduces the temperature. As long as there is an increase in the GHG induced air temp there will be an increase in convection/conduction as feedback, UNTIL they reach equilibrium, at the original temperature. This feedback will apply to any internally induced warming. eg albedo: less snow cover or clouds will absorb more energy into the ground, which heats up, which causes increase convection conduction and radiation by the multiple molecular collisions, which will increase the energy out of the ground, which will balance the energy in from outside, for NO change in temperature, and conservation of energy.
    But for an external solar forcing, the increase in incoming energy, causes increased convection, conduction and radiation, which results in increased energy out which results in a new higher energy-in equals energy-out. ie the warming we see every morning, & likewise a lower energy-in results in decreased temperature, every night.

    The implication is that any process that does NOT add or subtract external energy to change the temperature, will by itself cause a conductive,convective or even a radiative feedback, that will result in no change in the temperature. Mother Nature loves equilibriums. Only external forcings can cause global temperature changes. (ie Solar at this time, but try looking at changes in the Earth’s magnetic field energy which has been decreasing (where did the energy go to?) for the last century- This is apparently caused by the Sun or Jupiter’s changes in gravity and mag field effects on earth as relative orbit positions change) This then complies with the 2nd Law of Thermodynamics – ie Entropy, whereas the GCMs fail to comply again. The 2nd law of thermodynamics, says (in one of its forms) that you can’t get an entity (the globe) to raise its own temperature without adding work or energy from outside. Another version is: You can’t get something for nothing. OR There is no free lunch. GHGs causing warming is a free lunch (ie no external energy required).

    This is basically why I am a skeptic, and do not want to pay increased taxes to solve a problem (GHG warming) that doesn’t even exist. GHG induced global warming is an apparition created by a computer program. It is a GIGO fraud. There is no GHG caused global greenhouse effect, because convective etc feedback negates it. There is no need for carbon taxes or exchanges or carbon sequestration or the Kyoto treaty or IPCC, or Al Gore or worrying about methane burps.. Global warming caused by the sun exists (a rise of 4w/m2 out of 1364 since 1700 increases solar insolation by~ 0.3% which is the observed 0.84 K rise of the 288K current absolute temperature), but its very difficult to change that, so I’ll adapt to it.

    John Dodds

    PS I am folowing Hank’s suggestion and not commenting on analogies – they have a tendency to break down. But for the record, the radiative releases are more like going thru a giant screen with holes that are getting smaller due to increases in GHGs, rather than going over a dam. Radiative transfer is Like standing in front of a giant wave. No matter how much you try to stop it, it is going to get around you one way or another.
    & I agree with Steve, any tiny little delta increase due to GHGs gets a response from convective feedback. Also it works in reverse, any cooling effect gets a slowdown in convective feedback – eg at night there tends to be a very quiet no wind time at 3 am – ie the convection feedback has slowed the winds down below normal.

  13. 163
    Tom Fiddaman says:

    Re 161, 141

    Also, if there is *no* CO2 in the atmosphere there will be convection. CO2’s direct influence on convection (via gas properties) is almost certainly negligible; it’s the radiative influence on the temperature gradient that matters. I think there’s still some discussion about convective parameterizations in GCMs, but whatever you choose has to be consistent with a variety of data. The problem with postulating an arbitrarily strong convection feedback, as John Dodds seems to be doing, is that it’s hard to see how to reconcile that with observed lapse rates etc.

    The champion of these sorts of feedback arguments used to be Richard Lindzen, but he’s been pretty quiet lately, apart from making unsupported claims about supression of skeptical science. It’s never been very clear how to reconcile Lindzen’s ideas with paleoclimate, for example.

    Whether you like drains or weirs, my point was that there’s no mysterious violation of conservation laws when the lake level or temperature goes up – the increase is just the area under the curve when the inflow exceeds the outflow for a time (as in 140 above). A single drain at the bottom is sufficient, as long as the outflow isn’t turbulent (i.e. as long as the outflow is linearly dependent on water depth).

  14. 164
    Dan says:

    re: 162. “This is basically why I am a skeptic, and do not want to pay increased taxes to solve a problem (GHG warming) that doesn’t even exist. GHG induced global warming is an apparition created by a computer program. It is a GIGO fraud.”

    And there we have it. Previously it was pure arrogance for a layman to assume they knew more than the literally thousands of climate scientist modelers. Now it moves to a “head in the sand, no more taxes” approach despite astonishing, overwhelming scientific data and evidence to the contrary. And GCMs analyses that have been peer-reviewed extensively. This is far beyond being a skeptic. It is flat out denial of science and the scientific method, plain and simple.

  15. 165
    Tom Fiddaman says:

    Re 162

    The GIGO fraud here is your contention that the outflow of energy from a system is less relevant than the inflow. Perhaps you could write down a few equations describing how the atmosphere as you see it works, so that we’d have something concrete to reflect on, not a mumbo jumbo stew of physical principles misapplied.

  16. 166
    John Dodds says:

    Re 164. Tom, I believe in the Laws of Physics and most of what is in the GCMs – I think they are a marvel of modern computing (& I used to do computer modeling for a living) – just that they MAY have mistakes in them or MAY be missing pieces such as convective feedback(?) (eg Gavin has said that the GISS Model does NOT believe in Leap Years. – ie it runs on 365.0 days per year. Now does this mess up any of the data that is time dependant? SO far Gavin says no. but it sure seems to have the potential to put springtime back in Christmas if you are not aware of it)

    Please try to address my technical problems – eg 2nd large paragraph starting “However” above. Where is the misapplication? How can The physics (Stefan-Boltzmann) require the energy-out to be Larger for a hotter GHG caused temperature (this I accept), but the GCMs require a number lower than the energy-in to provide the source of the energy for global warming? To require a lower number for outflow means that we are NEVER in equilibrium, but it seems that the daily temp fluctuations will force us into equilibrium every day. – this implies that the computer program is wrong. IS IT? Where did I mess up? How do I resolve this apparent conflict?
    IF convective feedback HAS been incorrectly applied or partly missed in the GCMs, then this MIGHT solve MY problem- but it will also eliminate GHG warming.

    As for outflo being less relevant than inflow, I think that the inflow might dictate what the outflow MUST be (ie rules of entropy). and regardless of what barriers (GHGs, dams etc- I liked the dam analogy I would just prefer to use the real problem to talk about) we put in the way my gut tells me that the energy will find a way to get around the barrier to make the equilibrium work.
    SO just HOW can we justify that that the outflow in the computer MUST be less than inflow for the 250 years of the computer run, when clearly the daily temperature cycle will reestablish the equilibrium (at least for the atmosphere & ground – not sure about deep ocean equilibrium, BUT I also know that there is MUCH MUCH MORE energy stored in the Land (eg solid iron core of earth) than in the ocean & the GCMs do NOT address this either). I have questions that make the computer model seem to NOT work. I am asking for answers.

    Any GCMers out there who know for certain that the convective feedback identified in #142, is in there? (Hint hint Gavin!!) Since apparently the mechanism for adding energy for GHGs is by calculating the extra energy that GHGs add by staying in the air longer (ie increased transit time to space) was the equivalent (reduced transit time)for convective feedback included? OR does the program just calculate how much energy is moved to space by the fixed number for convection (& conduction – which apparently does not even have a number in IPCC docs) & ignore the reduced transit time via this pathway? Just asking???

  17. 167
    John Dodds says:

    Further thought about inflow=outflow. and 142 above.
    IF the energy required by the GCMs to create the rise in GHG induced temperature comes from the outflow to space (per Hank’s model in 137, which I thought was pretty reasonable), BUT IF the GCMs are required to have inflow=outflow @TOA (ie equilibrium – per #142 & the formal publications’ descriptions of the GCMs from GISS etc,) THEN WHERE IN (rhetorical) HELL does the energy come from to create GHG Global warming?

    Do we have a failure to conserve energy in the GCMs? By chance does the calculation to create the GHG energy absorbtion (ie GHG spectrum absorption etc which is as real as it gets) forget to create the mechanism to return this energy to space? Is it by chance the Convective feedback mechanism?
    Does this explain why the Solar can seem to account for the full measured 0.8C increase in global temperature (see #126), BUT the GCMs say that GHG warming should be 5 times larger than solar (1.5 vs 0.3 forcing -see Hansen et al above at the top.)
    ie the GCMs forgot to conserve energy???

    Careful with the answer to this – it implies that GHGs may NOT cause global warming.

    Sorry people, BUT I am getting more and more confused.

  18. 168
    Steve Hemphill says:

    Re #163:

    The observed lapse rate is the wet adiabat. Think about it. How could it be otherwise?

  19. 169

    Re #166 and “they MAY have mistakes in them or MAY be missing pieces such as convective feedback”

    I’ve explained to you before that convection has been modeled in atmosphere models since 1964. Either you didn’t read my posts or you’re deliberately ignoring them. In either case, stop repeating something that isn’t true!

    Also, your 4 W/m2 calculation for the Sun causing 0.6-0.8 K warming is off by a factor of three. I know because I’ve done that calculation, more than once, right here on Realclimate. Have you read what’s been previously posted here?

  20. 170
    L. David Cooke says:

    RE: #169

    Dear Mr. Levenson;

    Maybe I am taking things out of context in relation to your comment; however, I am curious as to your assertion. If I look at the standard accepted TOA value I get a measurement of approximately 1364watts/meter^2. If I look at ITCZ measurements on clear sky conditions I get a surface measurement of approximately 850 Watts/meter^2. If I look at the percentage reaching the ITCZ region of the TOA value it appears to be appoximatly 62.3%. If as the satellites indicate that during periods of soalr increases the value increases to approximately 1371 Watts/meter^2 and I multiply the standard of the 62.3% incoming then the 4 watts/meter^2 would be valid for direct incoming solar energy. What is wrong with this value? Are you suggesting that not all things remain constant and as the solar energy at the TOA increases that the direct energy penetration increases three fold?

    Dave Cooke

  21. 171
    John Dodds says:

    Tom: Re 168 Yes OK the observed lapse rate is the wet adiabat. So what is the implication that I am not aware of?
    When you add GHGs & the radiative absorbtion in the GCMs the calculated change in temperature changes the adiabat/lapse rate also. In order for the GCM to work, the temp profile has to change to increase the ground temp by 3+ degrees (assumed to be caused by the GHGs) BUT the TOA temp has to be the same to satisfy the energy-in=energy-out condition from BPL. All I am postulating is that the change from the GHGs does not exist due to convective feedback so the lapse rate is actually what it is today without the doubling of CO2. I do not understand the implications of your comment?

    Re 163 . I object to the “arbitrarily strong” characterization. IF the rise in temperature is caused by the radiative absorbtion by 390ppm of GHG (I agree), then the proposed increase in convective feedback is spread out over a MILLION ppm of air. The observed change in the convection rate will so so small as to be virtually undetectable, (390/1000000) & probably within the uncertainty of any parameterization of convection. (that I was not aware of, thanks)

    I do not understand how you can deny (impicitly) that an increase in ground/air temp by the GHG radiative effects (ie add 3+ degrees to the ground temp) will cause the convection/air velocity to increase. So my question remains (slightly modified & strengthened thanks to you) if convection was parameterized, and you radiatively increase the temperature by GHG absorbtion, then how do you account for the fact that increasing the air temp will increase the air velocity and convection and decrease the length of time that the convective air is in the globe? ie How to account for “convective feedback”?

    BPL: re 169. I am agreeing that convection has been modeled, & I agree that the GCMs have included an equlibrium energy-in equals energy-out at the TOA. My question is did they model the CHANGES in convection due to the GHG warming? what I call convective feedback.

    As for my calculation being off by a factor of 3, where is it off? It is a simple ratio of the change in solar insolation ( 4) to the value of the solar insolation (1364) taken from the IPCC chart ( If you want to account for the geometry effects of the insolation hitting only one side of the spherical earth, then you have to do it to both the numerator and the denominator. If you want to use the GCM value of solar forcing of 0.3W/m2, then you have to compare it to the same thing, apples to apples.

  22. 172
    L. David Cooke says:

    In reference to solar energy budget discussions:

    I just wanted to share a interesting presentation I have just discovered. For the layman such as myself, I believe this presentation appears to encapsulate a number of resources and discusses their participation in the Earths Energy Budget. I think that much of the data here may address issues that do not appear to get much play in the popular press. I would be interested in hearing comments regarding the science discussed here.

    Dave Cooke

  23. 173
    L. David Cooke says:


    In case there is confusion over the TSI as indicated in the fore mentioned presentation in which the average value is attributed to be around 240-247 watts/meter^2 the values can be much higher.

    The reference below from the Western Pacific Solar Radiative Insolation site indicates that the values appear to be as great as 1200 Watts/meter^2 Total Solar Irradance (and that is just for the long wave value).

    (The 850 watt estimate I used should be the average of the incoming full spectrum TSI during a clear sky day. If you average it across 24 hours and separate out the values acording to the various spectrum values then the average as indicated in the presentation above should be accurate.)

    Dave Cooke

  24. 174
    Hank Roberts says:

    Equilibrium is not reached for many, many hundreds of years — during which the planet heats up, and continues to heat up for a long while after the extra carbon stops being added.

    See here,
    you’re not alone in being confused:

    “… physical facts? We report experiments assessing people’s intuitive understanding of climate change. … The tasks require no mathematics, only an understanding of stocks and flows and basic facts about climate change. Overall performance was poor. Subjects often select trajectories that violate conservation of matter. Many believe temperature responds immediately to changes in CO2 emissions or concentrations. Still more believe that stabilizing emissions near current rates would stabilize the climate…. Such beliefs … violate basic laws of physics.”

    Read the abstract; download and read the PDF. It will help understand why equilibrium isn’t reached until long, long after the carbon quits being added by burning fossil fuels. During that time, the planet heats up.

  25. 175
    Tom Fiddaman says:

    Re 171 etc. Unfortunately I don’t have time to fully respond at the moment (hope to before the thread closes) but a few notes in passing:

    Re radiation vs. convection: the energy budget linked in 172 corresponds with others I’ve seen. (e.g. Fig. 2.1 in Global Warming: The Hard Science by L.D. Danny Harvey, Prentice Hall 2000) – the sensible and latent heat fluxes (conduction, convection, evapotranspiration) are 24 and 78 W m-2 vs. incoming solar of 342 and outgoing longwave of 235 W m-2. Thus the emphasis on radiation is understandable.

    Re 167 I think 142 is right about convection but wrong about the TOA radiation balance constraint. Models may be tuned to get the TOA balance right in equilibrium, but TOA balance is emergent, not enforced (and given that the models have internal variability, equilibrium is a rather fuzzy notion). The correct way to ensure conservation of energy is at the grid cell level, i.e. you make sure that there’s no creation or destruction of energy within each atmospheric cell and in transport processes among cells. I agree that if models constrained inflow=outflow at TOA, there would be no source of heat to drive warming, but they don’t. So, if you instantaneously put a lot of GHGs into an atmosphere that starts in equilibrium, radiative outflow < inflow and temperature starts rising. As things warm up, outflow rises (more longwave, more convection) until equilibrium is reached at a higher temperature. Given the sensible & latent heat transport #s above, it doesn’t seem very plausible for convection & conduction to play a role comparable to radiation (especially because latent heat transport also puts more moister in the upper atm, and that water vapor feedback traps more radiation).

  26. 176
    John Dodds says:

    Hank, Tom, Re 174/5
    Thanks for taking the time to respond.
    First comment- You say there is a long heatup time to get to equilibrium – I say it is IN THE GCM. & I think the GCM ignores convective feedback which would eiminate the long buildup time. Nice logic circle we’re in!!

    Why doesn’t the daily temp swing of 10-15 degrees on both sides of the equlibrium force the atmosphere to adopt the equilibrium in=out value? Since it passes thru the equilibrium energy-in equals energy-out point why would it go past it (except as driven by the daily forces less the inequilibrium part)? The daily temp cycles impact the entire atmosphere and a few inches of ground and ocean, there is no way to delay the effects of a GHG release until years out. (unless you hide it in the deep ocean & it takes time (more than a day) to get the effect down there) The daily fluctuations will eliminate/compensate for the imbalance in the first few inches of ocean depth within a few days at most.

    Corollary, does “convective feedback ” exist or not? ie When you heatup the air by the valid GHG radiative absorbtion process, does this higher temperature create a natural increase (ie CHANGE) in convection or Not? (eg does GHG warming cause stronger hurricanes in one extreme)
    If so, & I find it hard to deny, is it in the GCMs? I have not seen any numbers for it & if the logic works then it there should be a big negative convective/conductive feedback equal to the Radiative & GHG warming increase.

    Re the study – I quote Lincoln – you can fool all the people some of the time, some of the people all the time etc etc. This study can NEVER be scientificly conclusive. BUT very interesting anyway. Sorry guys, it just proves how gullible people are. It also proves that if you repeat a story (true or not) enough (ie GHGs cause warming) then people will believe it. SOrry, not conclusive – stick to the science please (to quote Gavin).

    In the GCM equilibrium is a fuzzy notion due to the modeling technique, In the world it is required for conservation of energy. It is absolute!

    THe Hard Science book quotes fixed numbers for convection etc . DO they ever change as a result of the GHG warming process. ie is there a convective feedback? True radiative transport IS bigger so look there first, but how can you ignore a tiny change in a whole lot of convective molecules?
    Now if you look at daily temp changes, when the sun raises the temp, the sun causes winds to change, hotter air to rise faster, and at night the winds die down as the earth cools off. Why wouldn’t the same process work for GHG caused warming? ie Convective feedback exists.

    I can see that adding GHGs creates a longer transport time in the air, hence warming, BUT wouldn’t the warmer temp create a shorter transport time in convection? (it would be very tiny since a million molecules have to move faster to compensate for 390 extra absorptions) If this is true then there is no delay time in reaching equilibrium & the daily temp cycles don’t have to do much at all to restablish it.

    Yhe only way I see out of this dilemma is to ask Gavin as a GCM expert a) is convective feedback in the GCM? Was it implemented when they added the GHG energy via the wavelength spectrum absorbtion process or was it assumed that the computer program took care of the conservation of energy. And B) what is its value? ie My understanding of convective feedback is that it was overlooked, & so when the GHG process was added it adds in the extra energy from GHG warming and forgot to subtract it out by convective feedback. SO we have an inadvertent net lack of conservation of energy.

    In my view convective feedback is capable of solving all MY problems (so far) with the GCMs. but it also means that the GHG impact is simply a transfer of some of the transport process from radiative to convective. ie Mother Nature (physics) has a perfect feedback mechanism that maintains energy equilibrium instantaneously regardless of how we mess up the atmosphere.

    AND since my version of the % rise in solar accounts for the observed 0.6 to 0.8 observed rise then the system would work if convective feedback exists. CAN you comment on my calculation of % temp rise in 126? It is extremly simple! Where can it be wrong? If it is correct then how can the GHG warming be a ratio of forcings (ie 1.5 over 0.3) higher which does NOT agree with the observed temperature increase.

    Thanks in advance.

  27. 177
    Hank Roberts says:

    You’re confusing weather with climate, John.

    Look at a weather map. Differences in air temperature persist. You believe that the air could quickly come to an equilibrium temperature by vertical mixing, without also mixing side to side, eh?

  28. 178

    Re #170 — Okay, I’ll run through it again.

    The emission temperature of a planet, the temperature as measured from some distance away, can be found with this equation:

    Te = (S (1 – A) / (4 sigma)) ^ 0.25

    where Te is in kelvins, S is the Solar constant, A the Earth’s bolometric Bond albedo, and sigma the Stefan-Boltzmann constant. S at Earth’s orbit averages 1367.6 Watts per square meter, the Earth’s albedo is about 0.3 (assume this is exact for the moment), and sigma has the value 5.6704 x 10^-8 in the SI, which gives an emission temperature for Earth of 254.9 K.

    Global warming since 1880 or so has been about 0.6 K. How much would the Solar constant have to have risen to provide that much of an increase? Solving for S, we have

    S = 4 sigma Te^4 / (1 – A)

    Plugging our results for Te back into this equation, it gives S = 1367.9 (which shows the problems of using significant digits). If we take Te = 254.9 – 0.6 = 254.3, we get S = 1355.1. In other words, the Solar constant would have to have increased by 12.8 Watts per square meter to get the observed warming. The Solar constant has, in fact, risen by about 1 Watt per square meter over this time period. Solar can’t do it alone without violating conservation of energy.

    There may be some feedback in the Earth system that “multiplies” changes in the Solar constant. But until the Solar freaks identify what that feedback is, their theory fails on basic scientific grounds.

    [Response: Paul, the argument is basically sound (and the answer qualitatively correct) but one needs to take into account that that the earth is really a ‘gray body’ and not a ‘black body’ to get the right answer. This increases the sensitivity to solar irradiance changes just as it increases the sensitivity to longwave (i.e., greenhouse) radiative forcing. There is a very nice site here at NYU which provides a simple energy balance model where you can tweak the longwave emission parameters away from their blackbody values (for example, to accomodate the existence of the greenhouse effect) and its easy to do simple experiments where you change the solar constant by a small amount, etc. I highly recommend this for folks who are interested (Matlab required!). One can learn quite a bit by playing around w/ simple models and getting a feeling for how the radiative balances work. -mike]

  29. 179

    Re #176 and “THe Hard Science book quotes fixed numbers for convection etc . DO they ever change as a result of the GHG warming process. ie is there a convective feedback?”

    Why don’t you get ahold of John Houghton’s “The Physics of Atmospheres” or Grant W. Petty’s “An Introduction to Atmosphere Science” and find out? The equation for the dry adiabatic lapse rate is very simple and has nothing to do with how warm the air is. The equation for the saturated lapse rate depends on how much water vapor is in the air and does have a temperature term, but doing the math shows that the effect of a few degrees temperature change on the lapse rate is trivial. You’ve got a qualitative theory (“changes in the lapse rate offset warming from CO2”) about what should be a quantitative problem. Do the math!

  30. 180
    L. David Cooke says:

    RE: #179
    Mr Levenson;

    However, the saturated adiabatic temperature differential at pressure does not appear trivial. At approximately 500mb most condensation appears to occur in relation to Stratus cloud formation. 300 mb appears to define the Cumulus Nimbus formation with peaks forming near 200mb. The temperature deviation at 500mb runs from -20Deg. C to over -40 Deg C. in the upper ranges (200mb) and the change in altitude can vary as much as 6 km over a wide spread area exceeding a column of 25 sq km. I find it kind of difficult to try to simplify this characteristic, which is why I was curious if maybe you could provide some clarification?

    (As an aside comment, there appears to be a curious association between atmospheric phenomenon and plate tectonics. As a natural phenomenon the size of the convective plume rivals the size of plate tectonic “hot spot” though as to temperature the relationship is not even close. (However, this is likely related to density of the material. If I remember correctly the heat content of the mass is related to the density at pressure, in addition to the latent heat capacity.) And if you look at the plate boundary physics you could almost see an allusion to the atmospheric fronts. It would almost seem that we have a physical model below our feet to help us to understand what is happening over our heads. The problem is that the transfer of heat between the layers in solid/plastic form and the liquid/gas form may be much different as the layers in the less dense material appear to deform to accommodate the exchange or transfer of energy.)

    Dave Cooke

  31. 181
    L. David Cooke says:

    RE: # 178

    Mr. Levenson;

    My thanks for your explanation. It seems so simple when you do the equations. For me I see far too many variables to be able to comfortably base my confidence of a lack of effect on a simple extraction for a change on the order you are indicating. Especially, when I consider the mechanics of the heat transfer remain to be defined. However, that is why we have scientists, to separate out the pepper from the fly spec and to keep things in perspective.

    Dave Cooke

  32. 182
    John Dodds says:

    Re 177, Hank et al
    Your denial that hotter air rises faster is totally unbelievable. ie Convective feedback must exist. The sun on a daily basis warms the air & the hot air rises to compensate ( & the atmosphere expands). My statement on the daily temerature cycling (it causes both vertical AND horizontal convection/weather) was intended to point out that the GCM contention that an energy-imbalance can exist for 100s of years, is impossible. If in exceeds out and the diffential MUST exist from top to bottom of the atmosphere, then before the hotter air can migrate to the deep ocean, the daily temerature cycling will force the hotter air at the bottom into an overall equlibrium ie hotter air will rise – or more correctly since GHGs have heated the air up more at the bottom, then the sun induced daily warming will add more heat to the top, & less at the bottom to force the equilibrium – ie effectively hot air rising even if not in actuality. This establishes the energy-in = out equilibrium EVERY DAY so a 100 year dis-equilibrium as calculated by the GCMs is impossible. YET another in the line of physics failures that the GCMs require. Note that IF the GCMs add in convective feedback equal to GHG warming then the problem goes away.

    IF daily solar heating causes (effective)convective feedback – to reesablish in=out, then why doesn’t GHG warming which adds 3+ degrees to the ground temp ALSO cause convective feedback. ie hotter air/energy to rise faster. & then WHERE IS IT IN THE GCMs?

    [Response: This is probably a mistake, but here goes. The long term imbalance is due to energy imblances at the surface of the ocean – not in the middle of the atmosphere. And these occur because it takes a long time for surface temperature anomalies to affect the deep ocean. Convection of course acts in the GCMs, and that is the principle reason why the atmosphere (particularly in the tropics) stays near a moist adiabat. This of course implies relatively constant relative humidity is therefore a big part in the water-vapour feedback. Thus when you ask ‘where is the convective feedback in GCMs’, the answer is in the water vapour feedback. -gavin]

  33. 183
    John Dodds says:

    A different perspective on the same problem: (try expanding your views a little)
    The is no argument that extra GHG absorbtion causes warming within the radiative transport mechanism.
    The mechanism as I have been taught (painfully) in the site, is because the addition of GHG absorbtion causes the energy to stay in the GHG for a few extra microseconds of residence time before the energy is (mostly) returned to the air by molecular collisions, as the energy is transported from ground to space an a series of millions(?) of absorbtions.

    NOW if you look at all three transport mechanisms, convection, conduction and radiation, it is actually the sum of the residence times in ALL three that determines what the extra temperature rise is due to transport thru the atmosphere. (Note that this INCLUDES GHG warming of the greenhouse gas heating effect as just a single part.)

    ie The greenhouse effect says that the absorbtion by GHGs causes the actual ground temp (288K) to be higher than the theoretical – 255K.
    In fact the greenhouse effect is mis named. since it is actually the TOTAL residence time of the energy as it is transported from ground to space that causes the difference in temperature. ie Convection residence time plus conduction RT plus radiation residence time.

    I propose that the total residence time is dictated by the in=out equilibrium, and the quantity ie density vs distance of the air.- ie ideal gas law?) (is this valid/reasonable?) regardless of individual constituents (limited by density changes) Because, in all the transport processes the energy can move between transport mechanisms in the air by molecular collisions every few centimeters. ie energy can easily move from conduction to radiative transport & back again etc.

    Thus if you change the air constituents (ie add GHGs) then the energy transported by radiative effects will increase, but the increase in GHG residence time will cause a feedback and decrease in conduction etc residence time (ie hotter air rising faster). ie Increasing GGs causes convective feedback to decrease the convection residence time. INORDER TO make the air conform to the ideal gas law.

    IF you can just add GHGs and add energy (by forcing a failure to comp;y with in=out equilibrium for 100s or years) then the air no longer complies with the ideal gas law. because the temp increase is larger than the trivial increase calculated by the density change of substiuting 390 ppm of CO2 for O2. ie Just adding GHG warming in the GSMs forces the ideal gas law to fail.

    Now go reread #126.
    If conductive feedback exists nearly equal to GHG warming, then this GCM failure to comply with the Laws of Physics ceases to exist., but so does warming,
    (Sorry I told you I was loking at the same problem!!)

    In all seriousness,
    Please think about it before you fire off a no it can’t be comment.
    John Dodds

  34. 184
    Tom Fiddaman says:

    Re 176

    Conservation of energy and equilibrium are not the same thing. If the world required equilibrium in order to conserve energy, a pendulum couldn’t oscillate. Equilibrium is a convenient notion for comparative static analysis in both physics and economics, but the atmosphere and the rest of the world are in more or less constant disequilibrium, and GCMs reflect that.

    The convection numbers I cited were from an energy balance diagram, not a model. The point is that a small flow (convection) can’t make up for changes in a large flow (radiation) unless you postulate an unrealistically high gain. To draw another bad analogy, it’s like assuming that a rise in the GDP of Delaware could compensate for a fall in California.

    Instead of badgering Gavin, why not just Google & read a few papers on convective parameterizations in GCMs? There are lots.

  35. 185
    Hank Roberts says:

    1. You’re forgetting the ocean’s heat capacity, and

    2. The references earlier will clarify how the atmosphere works.

    Read some of the current research, it’s not hard to find. There’s a huge amount of work being done. A few quick examples:

    “….. a significant increase in the height of the tropopause – the boundary between the turbulent troposphere, which is the atmosphere’s lowest layer, and the more stable stratosphere that lies above it…..
    The team’s results show that human-induced (anthropogenic) changes in well-mixed greenhouse gases, which are fairly evenly distributed in the atmosphere, and ozone, a greenhouse gas that is found in higher concentrations in the stratosphere, are the primary causes of the approximately 200-meter rise in the tropopause that has occurred since 1979. In their research, team members used advanced computer models of the climate system to estimate changes in the tropopause height that likely result from anthropogenic effects. They then searched for, and positively identified, these model-predicted ‘fingerprints’ in observations of tropopause height change.”
    The tropopause is among the most fundamental structures in the atmosphere. It is the interface between the water vapour-rich and dynamically active troposphere below and the ozone-rich and relatively quiescent stratosphere above. Traditional radiative-dynamical theories suggest that the position of the tropopause is determined by radiative-convective equilibrium in tropical latitudes. But this theory is not really consistent in the extratropics and we require a new theory to explain the position of the tropopause here. Dr I.Held (GFDL, Princeton) has already suggested that the position of the extratropical tropopause is determined by baroclinic eddies, which are the predominant form of large-scale motion in the extratropical troposphere. Professor Haynes and I are using numerical models, new diagnostic tools, and analytical techniques to try to assess Held’s suggestion. ….”

    You can _see_ the tropopause as well as read about it.

    From above:

    “When the rising cumulus columns meet the tropopause, or base of the stratosphere, at about 15,000 kilometers (50,000 feet), they reach a ceiling and can no longer rise buoyantly by convection. The stable temperature of the stratosphere suppresses further adiabatic ascent of moisture that has been driven through the troposphere by the 5-6.8 degree/kilometer (8-11 degree/mile) lapse rate.”

    From the ground:

  36. 186
    John Dodds says:

    Re response to 182.
    Hi Gavin, yes it was a mistake to start talking to me again. :) BUT I appreciate knowing that you read all this stuff. As you well know I am stubborn BUT I WILL learn when you show me the physics, or the process or my errors.

    If convective feedback is in the WV feedback (ie the negative convective feedback reduces the positive WV feedback ), then where is the convective feedback for the increased vertical velocity for the O2 & N2 in the air? GHG absorbtion results in GHG collisions with ALL the air, thus raising its temperature. (ie Hotter AIR, not just GHGs, rises faster. )

    Your statement is not very convincing – what are the values for it? How was it calculated. Did you calculate just the energy transport or did you calculate the reduced temp effect from the reduced residence time in the AIR also? (ie the reverse of the GHG residence time effect)

    Any comment on 183 as a new way to view the greenhouse effect, which is really a residence time effect NOT limited to GHGs?

  37. 187
    Tom Fiddaman says:

    Re 183

    Continuing your thought, the mean residence time is the harmonic sum of the individual residence times, so tau = 1/(1/tauRad+1/tauConv+1/tauCond). Conductivity of air is lousy so assume for the moment that tauCond is large so its term disappears. In equilibrium, the radiative and convective heat flows are Q/tauRad and Q/tauConv, where Q is heat. If the average flows are as in 175, 24 W m-2 for sensible and 235 W m-2 for outbound longwave, then tauConv must be about 10x tauRad, so for any change in tauRad (from GHGs) you need tauConv to change about 10x as much to compensate. Even if you take the convective flux as 24+78 W m-2 (including latent) you need better than a 2:1 change in convection, and some way to explain away the radiative effect of moving more water vapor up.

    I think things get even worse when you consider the real physics rather than the linear back of the envelope. Convection depends on the temperature gradient, not absolute temperature, so tauConv is only going to change if the gradient changes. But strong convective feedback would tend to hold the gradient constant, so radiation would again dominate.

    Why doesn’t the daily temp swing of 10-15 degrees on both sides of the equlibrium force the atmosphere to adopt the equilibrium in=out value? Since it passes thru the equilibrium energy-in equals energy-out point why would it go past it (except as driven by the daily forces less the inequilibrium part)?

    The argument that diurnal variations pass through the equilibrium point is incorrect. The equilibrium point varies with the forcing, which is low when the sun is down and high when it’s up. You are correct in noting that a first-order system won’t pass through its equilibrium point, but that’s not what’s happening here. A change in GHGs will change the balance of time during the day that temperature is above/below its equilibrium point, and thus change the average energy balance over the day.

  38. 188
    L. David Cooke says:

    RE: #187

    Mr. Fiddaman;

    I think I can see Mr. Dodds point though, the transfer of energy is not a constant 300 +/- 50 watts/meter^2. The value for the Western Pacific ARM.goiv site demonstrates a down welling longwave value of between 500 and 1000 watts for apprioximately 9 hours per day. The shortwave down welling irradiance appears to run about 400 watts 7×24 with peaks around 450 watts.

    (See archive link: )

    Would this not indicate a total TSI at the surface at the Western Pacific center of approximately 1200 watts for 9 hours/day and around 400 watts for the remaining 15 hours? Would not the 800 watts of energy difference cause a stong convective rise of atmospheric gasses / vapors for some period of time every day? This then would also be followed by a period of relative lack of convective forces.

    The character of the convective energy would seem to be an excellent application of a Granger statistical test for causuality to determine the relationship between the total incoming energy and the total outgoing energy. (It would be even more interesting as the incoming shortwave would now be emitted as longwave. Hence, the combination of the downwelling longwave reradiated back out and the shortwave energy converted to longwave radiated energy should signify a major imbalance in which the total energy balance is maintained; however, the character of the measure has now changed significantly.)

    If we take that even farther we now have increased the longwave upwelling imbalance even further as the surface energy with the first 10-25 meters will act as a feedback making the downwelling Longwave a product of not only the TSI; but, will include a portion of the reflected upwelling.

    Oh well, I guess this has all been taken into consideration so neither Mr. Dodds nor I need not worry.

    Dave Cooke

  39. 189

    Re #188 and “Would this not indicate a total TSI at the surface at the Western Pacific center of approximately 1200 watts for 9 hours/day and around 400 watts for the remaining 15 hours?”

    No, it wouldn’t. There is no Solar Irradiance at night.

    If you want the mean figure for Solar energy going into the Earth system, it’s

    F = (1/4) S (1 – A)

    where F is the flux in question, S the Solar constant (1367.6 Watts per square meter on average), and A is the Earth’s bolometric Bond albedo (Goode’s 1998 estimate is 0.298). F is thus about 239.3 Watts per square meter. The 1/4 factor integrates the fact that the Sun is down at night and that the Earth is a sphere and some irradiation thus “glances off,” so to speak.

  40. 190
    L. David Cooke says:

    RE: #189

    Mr. Levenson;

    The .25 value in relation to the area of direct energy seems a little contrived. If I look at most of the UV-A/B warnings they useually indicate that between local hours of 10AM through 2PM are the usual time of the highest incoming energy. This indicates that 4 hours are the point of highest gain or 1/6th the rotation of the earth. Are you suggesting that this value should be expanded to 9AM through 3PM? (It does seem interesting that in Oct. that the Western Pacific Radatiative Pyrometer seems to indicate that the incoming longwave energy exceeds 800 watts for nearly 8 hours per day or 1/3rd the rotation.)

    You are correct that using the single 1 sq. km column definition that there would not be a constant TSI; however, on a global scale that is not accurate as the black (gray) body has a constant TSI of roughly 40% and a constant radiative sink for about 60% of its surface. The fact that the black (gray) body is rotating must play a part in the difference in the radiative transfer for if it were not rotating the total heat transfer would be much different. (It becomes kind of confusing when I am discussing the apparent input and output of energy based on one model and your formula applies to the evidence under a different model; but, that was my fault, my apologies.)

    If you were to place an IR sensor in space, opposite the sun, to view the earth’s surface you would clearly see a glowing surface of higher intensity on the left with a very low level emission on the right. This would indicate that the emission levels are not constant, as Mr. Dodds was attempting to indicate. Also this would seem to indicate that the emission center of highest intensity is not direct back at the source but offset by about 25% from the angle of incidence. (I wonder if there is a chance that standingwaves or saturation can play a part in limiting the incoming energy?)

    I begin to wonder if a simple modeling radiative analysis is useful for anything other then obtaining a ball park value, with a variation of up to roughly 40% from the apparent median. It just concerns me that with this high a variation that a level of confidence, as you seem to share, can be so high. Then again it could just be a matter of you are dumbing the data down so that a layman such as I can understand it. My thanks for your contribution.

    Dave Cooke

  41. 191
    Hank Roberts says:

    > GHG absorbtion results in GHG collisions with ALL the
    > air, thus raising its temperature. (ie Hotter AIR, not just GHGs, rises faster. )

    Isn’t this confusing absorbtion of a photon and subsequent emission of a photon with Brownian motion?

  42. 192
    Tom Fiddaman says:

    Re 188

    I don’t in any way dispute that daily energy flows vary. I was just pointing out that daily variation doesn’t restore balance by driving the system through it’s equilibrium point. Even if the atmosphere is roughly first order, the equilibrium point varies with daily insolation, and radiation varies as much as convection.

    Granger testing convection is an interesting idea, but I suspect that there aren’t many good direct measurements of convection to work with.

    I think the downwelling/upwelling radiation you discuss is fully accounted for.

  43. 193
    Steve Hemphill says:

    All these quantitative analyses are academic. One has to remember that most of Earth’s surface is ocean, and we really don’t have nearly enough of an idea about ocean circulation. Until we do and can say what the rate of heat uptake by the ocean is, there’s no realistic computation possible about joules in vs. joules out (in the centuries or less time frame) which is, after all, the ultimate measure of “global warming”, correct? The atmosphere holds about as much heat as the top two meters of ocean.

    Then, after we have a handle on that, we need to consider the changes that surface heat concentration will induce in evaporation, which will affect cloudiness, iterate…

  44. 194
    L. David Cooke says:

    RE: # 191

    Thanks for the clarification, are you suggesting that the equilibrium point is based globally or on a column model? If the cloud aerosol contribution is as low as I have seen it attributed, would this not say that globally the equilibrium point should be fairly stable? Or is it that the aerosol/cloud contributions are much higher and the equilibrium is much more variable then seems attributed in most GCM?

    As to calculating values for convection, I can see that would be very difficult, as you apparently could not use cloud height and dimensions or water vapor from satellite sampling. However, as you said it is very difficult to determine the various photometric energy balances, between reflection, frequency transformation, absorption, radiation, convection, conduction, forcing (direct and indirect), feedbacks (direct and indirect), etc., …

    I have to admit the current state of the art in regards to climate change source data seems sparse and yet to see so many intelligent individuals seem so adamant about the physical processes that I wonder if the reported hypothesis�s are worth the read. I guess that is why there are so many questioning the premises in regards to Climate Change?

    Dave Cooke

  45. 195
    Hank Roberts says:

    Would you all define “equilibrium point” as you’re using it?

    I used it meaning — the final temperature reached after the planet stabilizes its heat balance, the way it’s used in defining climate sensitivity (the change in temperature starting at equilibrium, then doubling CO2 and waiting a few centuries til equilibrium is reached, with the planet three degrees or so warmer).

    I think others are using it meaning daytime local temperature?

  46. 196
    L. David Cooke says:

    Hey Hank;

    As we are using it in this case, the equilibrium point should be the residual global temperature median for a given total solar energy flux level for 1 rotation of the earth for a given angular relationship between the equator of the earth and the sun in relation to the standard planetary orbital plane.

    You apparently are using it as a projection into the future based on changes in the value of the radiative flux. Your application would seem to lack descriptive value in that you would not know what the “standard” equilibrium point would be comprised of. Is this the desired use of the term?

    As a standard, to define the change in the trend line, may be a better application, IMHO. It would seem to make more sense to use it as a comparative analysis of the equatorial angular relationship, year to year temperature median as it changes from year to year regardless of the flux in the contributing elements.

    This then could be the standard measure you then can modify in the models by changing the values of or add values for the contributing elements of the equilibrium standard. This way the equilibrium point would be very descriptive as it would be tied to a specific model or time period. I will leave it up to you to define what you believe should be the standard use of the term and comply with the consensus in the future.

    Dave Cooke

  47. 197
    Hank Roberts says:

    climate sensitivity = equilibrium temperature change for doubled atmospheric CO2 concentration

    You’re talking about weather, not climate.

  48. 198
    L. David Cooke says:

    RE: #197


    But is climate not the trend in weather? Is it climate that defines change in weather over time or the change in weather over time that defines climate. I suspect it is the later and hence the energy balance over time due to the various influences that drive the day to day weather is what becomes climate. Are you suggesting that weather and climate are not related? (Mirriam and Websters define climate as: 2 a : the average course or condition of the weather at a place usually over a period of years as exhibited by temperature, wind velocity, and precipitation.) Are you suggesting that meteorologists would not make good climatologists?

    (Actually, I believe what you are refering to, is as your link pointed out, the IPCC definition of equilibrium climate sensitivity, and not simple solar radiative equilibrium, as we have been discussing in these last few posts.) Does this help reduce the confusion?

    Dave Cooke

  49. 199
    Tom Fiddaman says:

    Re 195

    I meant equilibrium in the normal sense, i.e. a condition in which the states of the system are constant, with inflows=outflows. The reason I originally said that this was a fuzzy notion in GCMs (and the real system) is that they’re not low-order systems with constant average forcings, and equilibria might not even exist. Nevertheless its sometimes helpful to think about them as if they’re low-order systems and to talk about equilibrium, under the assumption that the envelope of variable behavior moves in a predictable, low-order way. But it’s important not to confuse the map with the territory. In particular, it’s not OK to invoke variability arguments in a 1st order mental model – you need to explicitly model what’s going on if you want to talk about the details, which is why there are GCMs.

  50. 200
    Hank Roberts says:

    Note that ‘equilibrium’ in this thread — up through response 162 — was in terms of climate sensitivity, answering the question about where the ‘extra heat’ comes from.

    Starting with #162 —- the ” FAILS to comply with the Laws of Physics” posting — it’s being used by Mr. Dodds to explain something in his new theory about how greenhouse gases don’t …. whatever.

    Makes no sense to me, I’m done.