Five Reasons Why Water Vapor Feedback Might Not Be Positive

September 14th, 2010 by Roy W. Spencer, Ph. D.

Since it has been a while since I have addressed water vapor feedback, and I am now getting more questions about it, I thought this would be a good time to revisit the issue and my opinions on the subject.

Positive water vapor feedback is probably the most “certain” and important of the feedbacks in the climate system in the minds of mainstream climate researchers. Weak warming caused by more carbon dioxide will lead to more water vapor in the atmosphere, which will then amplify the weak warming through water vapor’s role as the atmosphere’s primary greenhouse gas.

Positive water vapor feedback makes sense intuitively. Warmer air masses, on average, contain more water vapor. Warmer air is associated with greater surface evaporation rates, which is the ultimate source of almost all atmospheric water vapor.

And since water vapor is the atmosphere’s main greenhouse gas, most scientists have reasonably inferred that climate warming will be enhanced by increasing water vapor amounts. After all, water vapor feedback is positive in all of the IPCC climate models, too.


But when one looks at the details objectively, it is not so obvious that water vapor feedback in the context of long-term climate change is positive. Remember, it’s not the difference between warmer tropical air masses and cooler high-latitude air masses that will determine water vapor feedback…its how those air masses will each change over time in response to more carbon dioxide. Anything that alters precipitation processes during that process can cause either positive or negative water vapor feedback.

Here are some of those details.

1) Evaporation versus Precipitation

The average amount of water vapor in the atmosphere represents a balance between two competing processes: (1) surface evaporation (the source), and (2) precipitation (the sink). While we know that evaporation increases with temperature, we don’t know very much about how the efficiency of precipitation systems changes with temperature.

The latter process is much more complex than surface evaporation (see Renno et al., 1994), and it is not at all clear that climate models behave realistically in this regard. In fact, the models just “punt” on this issue because our understanding of precipitation systems is just not good enough to put something explicit into the models.

Even cloud resolving models, which can grow individual clouds, have gross approximations and assumptions regarding the precipitation formation process.


2) Negative Water vapor Feedback Can Occur Even with a Water Vapor Increase
Most atmospheric water vapor resides in the lowest levels, in the ‘turbulent boundary layer’, while the water vapor content of the free troposphere is more closely tied to precipitation processes. But because the outgoing longwave radiation is so much more sensitive to small changes in upper-layer humidity especially at low humidities (e.g. see Spencer & Braswell, 1997), it is possible to have a net increase in total integrated water vapor, but negative water vapor feedback from a small decrease in free-tropospheric humidity. See #4 (below) for observational support for this possibility.

3) Cause Versus Effect

Just because we find that unusually warm years have more water vapor in both the boundary layer and free troposphere does not mean that the warming caused the moistening.

There are a variety of processes (e.g. tropospheric wind shear causing changes in precipitation efficiency) which can in turn alter the balance between evaporation and precipitation, which will then cause warming or cooling as a RESULT OF the humidity change – rather than the other way around.

This cause-versus-effect issue has been almost totally ignored in feedback studies, and is analogous to the situation when estimating cloud feedbacks, the subject of our most recent paper.

Similar to our cloud feedback paper, evidence of causation in the opposite direction is the de-correlation between temperature and humidity in the real world versus in climate models (e.g. Sun et al., 2001).

4) Evidence from Radiosondes
There is some evidence that free tropospheric vapor has decreased in recent decades (e.g. the Paltridge et al., 2009 analysis of the NCEP Reanalysis dataset) despite this being a period of surface warming and humidifying in the boundary layer. Miskolczi (2010) used the radiosonde data which provide the main input to the NCEP reanalysis to show that the resulting cooling effect of a decrease in vapor has approximately counterbalanced the warming influence of increasing CO2 over the same period of time, leading to a fairly constant infrared opacity (greenhouse effect).

Of course, water vapor measurements from radiosondes are notoriously unreliable, but one would think that if there was a spurious drying from a humidity sensor problem that it would show up at all altitudes, not just in the free troposphere. The fact that it switches sign right where the turbulent boundary layer pushes up against the free troposphere (around 850 mb, or 5,000 ft.) seems like too much of a coincidence.

5) The Missing “Hot Spot”
Most people don’t realize that the missing tropospheric “hot spot” in satellite temperature trends is potentially related to water vapor feedback. One of the most robust feedback relationships across the IPCC climate models is that those models with the strongest positive water vapor feedback have the strongest negative lapse rate feedback (which is what the “hot spot” would represent). So, the lack of this negative lapse rate feedback signature in the satellite temperature trends could be an indirect indication of little (or even negative) water vapor feedback in nature.

Conclusion
While it seems rather obvious intuitively that a warmer world will have more atmospheric water vapor, and thus positive water vapor feedback, I’ve just listed the first 5 reasons that come to my mind why this might not be the case.

I am not saying that’s what I necessarily believe. I will admit to having waffled on this issue over the years, but that’s because there is evidence on both sides of the debate.

At a minimum, I believe the water vapor feedback issue is more complicated than most mainstream researchers think it is.

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108 Responses to “Five Reasons Why Water Vapor Feedback Might Not Be Positive”

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  1. ruidh says:

    You say “the resulting cooling effect of a decrease in vapor has approximately counterbalanced the warming influence of increasing CO2 over the same period of time, leading to a fairly constant infrared opacity (greenhouse effect).”

    But, how long can this continue to mask the signal? Eventually the troposphere has to either run out of water vapor or a new, lower steady state is reached. It has to be strictly a short-term effect and one, if it reverses itself for whatever reason, could unmask previously hidden warming.

    • because the relationship between outgoing longwave radiation (OLR) and humidity is so non-linear at low humidities, the “buffering” capacity would be huge.

      Of course, there are negative reflected sunlight feedbacks (which I consider more likely than negative water vapor feedback)…

      plus the fact that we will be developing alternative energy sources this century anyway, if only because carbon-based fuels will slowly become more expensive and because everyone needs energy, which means the free market is incentivized to find and reduce the cost of new energy sources.

  2. Water vapor feedback is way more complicated then most people think. It is only partly understood and a dynamic process. Like most, if not all natural processes or dynamic systems, they are always tending or trending to some kind of equilibrium; however, that equilibrium is a continually moving target. If we step back from our positions or beliefs on this or any other natural process, we quickly come to the conclusions that we are still grossly ignorant. Yes water plays a role in climate but we are still not truly sure exactly what that role is. We have a lot of the puzzle pieces that is true, we are still not quite sure how they fit together. Instead of trying to force dynamic, parly understood process into oversimplified, deterministic numerical models, we should be spending our time trying to falsify and refine our hypothesis. We need to reexamine our assumptions and start using empirical data. Any geologist can tell you the earth is never in any kind of true equilibrium or steady state when viewed on natures time scale.

  3. johnd says:

    Evaporation and water vapour is certainly an interesting area, and what makes it doubly interesting is trying to correlate what is theorised with what can be observed real time.

    Wind is a very important factor in driving evaporation, even on cool days, surface moisture can be evaporated at astonishing rates, and over the oceans winds whipping up surface sprays increase the surface area of the water to absorb heat thus increasing evaporation rates.
    How is wind factored into any formulas used to measure evaporation?

    Temperature measured at the surface varies from air temperatures measured by standard means 1.2m above the ground.
    In direct sunlight, a thermometer at ground level would find at times temperatures high enough to fry and egg, so is it those temperatures that are used, or the standard air temperature.
    At nights we see a different scenario. I’ve been following data collected by the Australian BOM in relation to evaporation, and at night, on almost every occasion, at every station across Australia, the terrestrial minimum temperature measured 25mm above the actual ground surface is always with only the odd exception, lower than the minimum air temperature measured in the standard screen, and lower than the soil temperatures which are very stable. This aspect interests me regarding given back radiation is supposed to be a large influence in helping to provide the heat energy that drives evaporation.

    Is the evaporation process directly driven by solar radiation, which in turn varies with cloud cover, whilst the heat content of the surface and the back radiation of the atmosphere are only incidental factors?

    Lastly, whilst the amount of water vapour suspended in the atmosphere depends on the temperature of the atmosphere, why is it not considered that the opposite applies and the temperature of the atmosphere is dependent on the amount of water vapour in the atmosphere due to the heat contained within.

    • kuhnkat says:

      Could you point us in the direction of the BOM data on this and how they collect it??

      Thank u in advance.

  4. RiHo08 says:

    Climate change appears to be a global impacted issue. There are, however, local weather experiences that suggest much is not known regarding climate change. I am referring to the recent effect of 6 days of gale or near gale winds upon the air and water temperature measurements on the North Lake Huron (one of the Great Lakes fresh water) buoy 45003. The temperatures fell 9 degrees Celsius. Wind turbulance changed the surface and subsequent water temperature measuremnts downward in just 6 days. Is it likely that water and subsquent air temperature measurements are impacted by the effecs of the wind. Isn’t wind influences basically turbulent? and, not remotely able to be mathmatically modeled? Haven’t we missed the effects of turbulence upon temperature, land and sea, so far? I think so. And we can’t even model accurately what the “natural” influences upon global temperature are, let alone the human (other than land uses) might be. I see people who keep plugging away at developing a data base, and I applaud them. I see others who view their knowledge base ase solid, I don’t believe them.

  5. Christopher Game says:

    Christopher Game responding to Dr Spencer’s blog article Five Reasons Why Water Vapor Feedback Might Not Be Positive posted September 14th, 2010.

    Dear Dr Spencer,

    This article is about a question of great interest and importance to me, and I am very glad to read your opinion about it, because you are a most reliable and admirable scholar in this area. I suppose this will be true for others besides me.

    According to Hansen, Johnson, Lacis, Lebedeff, Lee, Rind, and Russell (1981) ‘Climate Impact of Increasing Atmospheric Carbon Dioxide’, Science 213 (4511): 957-966, “The surface temperature resulting from the greenhouse effect is analogous to the depth of water in a leaky bucket with constant inflow rate. If the holes in the bucket are reduced slightly in size, the water depth and water pressure will increase until the flow rate out of the holes again equals the inflow rate.” I quote this verbatim because without the exact words, readers may not believe that such an important matter could be represented in print with such poor quality physics. The model was elaborated in an article by Hansen, Lacis, Rind, Russell, Stone, Fung, Ruedy, and Lerner (1984), in a report IRN 1263184X for the American Geophysical Union, published at pages 130-163 in ISBN 0875904041.

    This very same leaky bucket model is at the heart of the IPCC “forcing and feedback” formalism and still apparently dominates the minds of Schmidt, Ruedy, Miller, and Lacis (2010) cited in your previous-but-one blog article On the Relative Contribution of Carbon Dioxide to the Earth’s Greenhouse Effect, posted September 10th, 2010. As I myself read their article, it seems to me that those authors have made no intellectual progress since 1981; and this in a subject that threatens to be used to destroy our industrial society.

    This leaky bucket model is wrong in physics because the outflow of water through the holes in the bottom of the bucket is a nearly linear function of the depth of the water in the bucket, and because it has only one real sensed feedback variable, the depth of the water.

    The radiation from the land-sea body of the earth is perhaps about at the fourth power of its temperature. This is a non-linear dependence, quite at variance from the linearity of the bucket analogy. Worse, the climate is known to have at least two major metastable dynamical régimes, the glacial and the current pleasant one. A metastable dynamical régime is “locally” stable but not “globally” stable. That means that a moderate perturbation cannot shift the state of the system from one régime to the other, but a large perturbation can do so. Metastablility cannot occur in a linear model. A linear model with just one real sensed feedback variable cannot be more stable than “marginally stable”, that is to say it has no dynamically preferred stationary state, no point about which one can define “positive” or “negative” feedback. For a dynamical system to have two metastable states, at least two real sensed feedback variables are mathematically necessary. Yet the IPCC formalism is built on the leaky bucket physics, with at best a marginally stable régime.

    A more suitable simple model is that of a saucepan boiling on a stove. No matter how much you turn up the gas, you can’t make the water much hotter than the boiling point at 100C.

    The climate analogy is in the “protected towers of deep tropical convection” of H. Riehl and J.S. Malkus (1958) ‘On the heat balance in the equatorial trough zone’, Geophysica 6: 503-538, also referred to by Drs Lindzen, Hou, and Farrel (1982) as ‘penetrative convection’. Such a tower is illustrated in your diagram in this post showing the boundary layer, the precipitation microphysics, and the free troposphere. There are some thousands of these towers around the equator at any time. You can see them from your aeroplane window if you fly over the equator during the day. They are about 20 km in diameter, and 17 km tall. They are analogous to bubbles in boiling water. The ‘boiling point’ is at about 29C tropical ocean temperature.

    The ‘bubbles’ form in a dynamical régime that has several real sensed feedback variables, is importantly non-linear, and has dynamical structure that is perhaps metastable. This kind of dynamical régime has an interplay of diverse feedbacks that can be considered locally as “positive” or “negative”. The boiling régime can be described as an example of phase pinning, because it is governed by a dynamical phase change. For a detailed analysis of an example of this kind of thing, one may consult S. Chandrasekhar (1961) in Chapter 2 of Hydrodynamic and Hydromagnetic Stability, Oxford University Press, Oxford.

    It is simply a travesty of physics that the IPCC still persists with its linear/one-real-sensed-feedback variable “forcing and feedback” formalism.

    Dr Spencer, your article here is a very welcome discussion of the possibilities of positive and negative feedback. Your diagram, which might be interpreted to describe a protected tower of deep tropical convection, mentioned above, does not make explicit, but does point implicitly to a diversity of local feedback mechanisms, some positive and some negative.

    Dr Spencer, of special interest to me are your remarks about the article of Paltridge, Arking and Pook (2009) (wave flag for Australian and American co-authors!!) about the notoriously unreliable water vapour measurements from radiosondes. These questions of data reliability are for heavy-weight experts in meteorology and climatology.

    Dr Spencer, if you could suggest how to find an acceptably reliable radiosonde dataset of the full 1948-2008 epoch, it would be very much valued. It seems to me that the full 60 year interval is needed because of the probable 60 year period of some of the great climatic cycles. I would be very grateful to read more of your critical thinking about this dataset problem. Dr Miskolczi would be, I suppose, very glad if an acceptably reliable dataset could be found to further examine this matter.

    Yours sincerely,

    Christopher Game

  6. Skorrent says:

    Anxiety about positive warming feedback might be justified if our world were a few centuries, or even a few millennia, old. Instead, on our billions-old planet, we have records of much-higher CO2 levels (no temperature forcing), much higher surface temperatures (no static end state), and much variation in climate (back and forth). In spite of our scientific naivete, we can be pretty certain that if there were a single, simple, positive-feedback forcing factor for our climate, hot or cold, sometime in the last six or so billion years we would have found it, and be stuck in it.

    We ain’t, so there ain’t.

    Be a little humble, scientists.

    • Anonymous says:

      Christopher Game replying to Skorrent’s post of September 14, 2010 at 6:20 PM.

      Dear Skorrent,

      What about the possibility that I think rather likely, that indeed the we (or the earth before life) did find it some billions of years ago, or perhaps some ten thousand years ago, and we are now enjoying its beneficent effects, and therefore cannot hope for more of it, because we are already getting the best it can offer?

      Yours sincerely,

      Christopher Game

  7. Ray says:

    If you were to ask the general public what was responsible for most of the projected “global warming”, I think that they would probably say CO2. Most are probably unaware that Water Vapour and the feedback assumed in models is the main cause. It is obvious to me, that while temperatures are rising, they are not rising as fast as one would expect simply from ever increasing levels of CO2, so it seems likely that the feedback assumptions made in models is excessive. However, the public remains blissfully unaware of the uncertainty in this area of climate modelling, while the emphasis in the propaganda is almost entirely on CO2, and the fact that “the science is settled”.

    • Anonymous says:

      Actually Ray, I believe that, in most of the models, water vapor as a feedback has only about one-half the presumed effect of CO2 >> 1.2 degrees C from CO2 doubling, and an average of about 0.6 degrees C from increased H2O as a result of warmer temps.

  8. Nice clear exposition, thanks Roy. I wonder if you might be interested in the rather good correlation I found between specific humidity at the tropopause and solar activity:
    http://tallbloke.files.wordpress.com/2010/08/shumidity-ssn96.png
    Discussion here:
    http://tallbloke.wordpress.com/2010/08/08/interesting-correlation-sunspots-vs-specific-humidity/

    If solar activity is playing a role in controlling the level of humidity in the upper atmosphere at the boundary between the troposphere and the stratosphere, it would seem to me that the strong levels of solar activity in the latter half of the C20th may have had a much bigger part to play in ‘global warming’ than a calculation of the change in TSI at the top of the atmosphere would account for in simple energy terms.

  9. John_in_Oz says:

    The following reference http://www.jpl.nasa.gov/news/news.cfm?release=2009-196 asserts that
    “AIRS [the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft.] temperature and water vapor observations have corroborated climate model predictions that the warming of our climate produced as carbon dioxide levels rise will be greatly exacerbated — in fact, more than doubled — by water vapor,”
    Do you have data that contradicts these claims?

    • John, the AIRS data do NOT exclude explanations other than positive water vapor feedback. At face value, they are consistent with it, but in no way prove it. We showed this theoretically in Spencer & Brawell (2010). And the two references I provided (Paltridge, 2009; Miskolczi, 2010) DID use data to support negative water vapor feedback.

      Based upon your question, I suspect you either did not read my post, or didn’t understand it.

  10. Pavol Zeleny says:

    Mr. Spencer, how you explain the warming of six degrees Celsius, which occurred in the transition from the last Glacial to the Holocene with a low value of your climate sensitivity ?
    Thank you

    • Anonymous says:

      There are two competing (though not necessarily correct or mutually exclusive) trains of thought. The first is what you seem to allude to, which Hansen&co believe stridently. That is, the weak orbital variations caused a small change in the insolation values (smallest in the Tropics, noticable at the poles) and that resulting feedbacks in the ice sheets and the carbon cycle amplified these changes and resulted in around 5 – 7C of change.
      That is the dominant paradime. However, there is a competing set of ideas IN THE PEER REVIEWED literature. That is, that stocastic variations resulting from internal dynamics caused the change themselves without much aid from the orbital cycles, and as Dr. Spencer points out in his newest book, the correlation between the orbital cycles and the glacial temperature trends has been said by some to be spurious, or by chance, with no real physical connection. Given such, carbon cycling would have little effect on the temperature changes.
      I am NOT saying that internal variations did cause the glacial cycles, just that it is being postulated by some in the literature. I personally think the variations do correlate well, but that internal variations (as well as ice and carbon changes) had a large impact on the overall glacial cycles. Even if these internal variations only cause a small amplification to the orbital cycles, then that would decrease the needed sensitivity to CO2. Thus, the glacial cycles are not necessarily a negation of a possible not-so-positive water vapor feedback.

      • Anonymous says:

        There is also some ‘proof’ in the mathematics of chaos.

        If one assumes that climate can be defined by the maths of chaos then this predicts the possibility of sharp changes in equilibium without any natural forcing.

    • I try to stick to fields where we have data that can be tested. Understanding the major glaciations does not fall in that category.

  11. ArndB says:

    # “water vapor feedback issue is more complicated than most mainstream researchers think it is.”

    If the atmospheric water vapor is completely replaced for about 35 times during one single year, and the ocean replace by far the most of the precipitated water, how can reasonable answers on climatic change issue be given without evaluating the physical role of the oceans and seas, over all time periods from seconds to years, based on the understanding that “Climate is the continuation of the ocean by other means”, particularly with regard to water and heat, to name only two. http://www.whatisclimate.com/ , or to say it with Leonardo da Vinci (1452-1519): “Water is the driver of nature”.

  12. Andrew says:

    If I understand correctly, it cannot be the total precipitation that matters in point 1 (this must eventually equal the evaporation in the same way that outgoing long wave radiation must equal the incoming shortwave eventually) but which responds more quickly?

    Okay, allow me to explain conceptually. At t=0, we increase the temperature by some amount. At t=1, say the precipitation has increased and the evaporation has increased BUT one has only increased half as much as the other. At t=2, the are equal again. HOWEVER! If at t=1 it was the precipitation which had increased more slowly and had yet to reach equilibrium, then there would be a net increase in water vapor from the briefly greater evaporation flux. On the other hand, if precipitation had reach it’s new level before evaporation, there would be a net decrease in water vapor. Is this kind of the situation?

    At equilibrium I just can’t see a net difference between the terms (evaporation and precipitation) occurring.

  13. Christopher Game said:
    “Dr Spencer, if you could suggest how to find an acceptably reliable radiosonde dataset of the full 1948-2008 epoch, it would be very much valued.”

    If the apparent relationship between solar activity and specific humidity at the tropopause I linked above is indeed real, the NCEP re-analysis of the radiosonde data might not be as inaccurate as previously feared.

    • There is no other radiosonde datasets, unless they exist in a parallel universe or something.

      • Anonymous says:

        Christopher Game responding to Dr Spencer’s post of September 15, 2010 at 7:47 AM.

        Dear Dr Spencer,

        You write: “There is no other radiosonde datasets, unless they exist in a parallel universe or something.”

        Thank you for that info.

        Is it likely or possible that those radiosonde datasets will be somehow improved or corrected by suitable experts?

        Do you have an opinion about Rog Tallbloke’s September 15, 2010 at 6:55 AM proposal that the sunspot number series to some extent corroborates the specific humidity series?

        Yours sincerely,

        Christopher Game

  14. vboring says:

    Considering that water vapor and clouds strongly influence the climate, that forests are more efficient at creating water vapor and clouds (trees emit organic cloud nuclei in addition to more water vapor than non-forested areas), then does it stand to reason that deforestation could have a larger impact on terrestrial temperatures than currently modeled?

    I imagine forests are pretty well modeled from a water vapor perspective, but the talk about their cloud nuclei emissions was considered news by science daily sometime in the last year or two:

    http://www.sciencedaily.com/releases/2009/05/090517143334.htm

    http://www.sciencedaily.com/releases/2008/11/081119171523.htm

    http://www.sciencedaily.com/releases/2010/06/100607165744.htm

  15. Christopher Game says:

    Christopher Game responding to the post of Andrew at September 15, 2010 at 6:45 AM.

    Dear Andrew,

    I think your comment here is valuable and clarifying. It must be the relative timing of the changes of evaporation and precipitation that determines the effects on humidity, jsut as you say.

    Yours sincerely,

    Christopher Game

  16. Gator says:

    For many years I have surmized that water vapor is a cooling agent. When water evaporates it absorbs heat. This warm moist air rises, loses its heat and returns to the surface. This is obviously an overly simple explanation but explains alot of the heat transfer we see in our atmosphere.

    I have lived in tropical regions where swamp coolers are used. It would seem conterintuitive to add water vapor to an already hot and humid area in an attempt to cool oneself, but it works. The secret is ventilation. As long as the excess water vapor is allowed to escape the “atmosphere” you are trying to cool, it works.

    • Water vapor has both cooling (evaporation) and warming (greenhouse) effects on surface temperatures. See my previous post for the surface cooling effects of weather, which is mostly due to evaporation.

    • Anonymous says:

      I absolutely do not believe that swamp coolers have anything but a negative effect on cooling in tropical areas. I use swamp coolers myself here in New Mexico and they work great when the humidity is low, but in mid-summer when the humidity is high, they can raise the temperature by several degrees as the water vapor condenses on the furnature and carpets and make it more uncomfortable. In this case, it is best to turn the water off and simply use the fan.

  17. WhyI'mSkeptical says:

    But what keeps all the water vapor in the atmosphere? Mainstream view suggests its the long lived GHGs, hence all the concern with emissions. Although as Spencer notes we don’t have data for glacial cycles, a 100 ppm change in co2 over 5 kys is unlikely to be the key driver which raises sea level by 100m! Something doesn’t add up.

  18. ClimateWatcher says:

    I would like to offer two other reasons:

    6.) Subsidence

    For a given GHG, the radiative effects are due to:
    A.) the profile of the constituent ( how it varies with height)
    and
    B.) the profile of temperature

    In the homosphere, CO2 is well mixed, so the cooling rate
    appears to peak at the top of the homosphere (~ 1mb) where
    CO2 diminishes rapidly with height as seen here:

    http://www.aer.com/images/rc/lbl_clrt_mls.gif

    within the homosphere the cooling rates seem to
    vary more with temperature (indeed warming at
    the base of the tropopause inversion).

    Water vapor, on the other hand is not well mixed,
    but diminishes with height, on average, through the
    troposphere. Combined with the normal lapse rate
    of the troposphere, this leads to a peak cooling
    due to water vapor in the upper tropopause.

    Were water vapor to increase within the
    troposphere, but not the stratosphere,
    which would be consistent with AGW GCMs,
    the cooling rate of the upper troposphere
    would necessarily increase.

    And radiative cooling in the upper troposphere is
    what leads to subsidence:

    http://davidsmith1.files.wordpress.com/2008/06/0615081.jpg

    Subsidence accomplishes an important negative
    feedback to increased water vapor
    by leading to drier air over more humid air.
    This increases the emissivity to space because
    the water vapor from the base of the subsidence
    is emitting at a higher temperature than if
    the moist air had not subsided.
    (Indeed the signature of a subsidence inversion
    on a SkewT chart is divergent temperature and
    dewpoint traces. )
    http://www.aer.com/images/rc/lbl_clrt_mls.gif
    The areas of convection are limited to most prominently the ITCZ
    and frontal boundaries. The areas of subsidence are

    7.) The General Circulation

    Dessler’s papers seem to focus on variation of tropical
    water vapor with respect to short term El Ninos.
    One of the problems with this analysis is that
    tropical and indeed global water vapor is dominated
    by the ITCZ. And the ITCZ represents the convergence
    of the general circulation originating from opposite
    polar air masses. Thus, and intensification of the
    general circulation by increased polar cooling,
    can bring about increased convergence at the ITCZ,
    and so increase upward transport of water vapor.

    Both of these processes, Subsidence and the General
    Circulation, are dynamic modifiers.
    Evaporation, after all, acts at the surface, over water.
    Motions which counter the transport upward and
    outward from that point can revert tendencies
    toward increased water vapor.

  19. George E. Smith says:

    Well is water vapor really that complicated ? I’m sure it is possible to make it that complicated; but it is also very easy to make it a whole lot less complicated.
    First off; does anybody really believe that earth would have its present balmy range of surface Temperatures somewhere between about -90 deg C min at places like Vostok; to maybe more than +60 deg C in the Arabian summer deserts and everywher in between; IF there was no water on earth and the atmospheric CO2 content had from time to time been somewhere between maybe 150 and 7000 ppm (anywhere you like). Well I don’t. Without H2O we’d all be freezing.
    So now I think you can liken how water works; with a kitchen sink.
    You turn on the water and the water level rises (vapor in the atmosphere). It’s a perfectly good GHG so it absorbs LWIR, and heats the atmosphere; which in turn re-radiates to the surface and cause more evaporation (absorbed in the top 10 microns or ocean). So there you have a perfectly good positive feedback; so the water in the sink keeps on rising. But hold on a minute; water (vapor) is a perfectly good absorber for maybe up to 20% of the total solar spectrum energy from about 760 nm to maybe 2-3 microns. So that also heats the atmospehre but that is solar energy that does not reach the ground. About half of it goes upwards to escape, and the other half down converted to LWIR goes towards the surface (only half of it). So that is a net loss of solar energy that doesn’t reach the surface. The more water vapor; the more solar energy that doesn’t reach the surface. If that isn’t negative feedback, I’ll eat my hat.
    So Ok we have to pull the plug in our kitchen sinkto get a negative feedback; the higher the water rises; the greater the pressure driving it out the drain; so you see it is a negative feedback. But without water in the sink you don’t get any negative feedback draining; so we know the sink has to have water in it. But how much ? If it keeps on rising due to the positive feedback excess over the negative feedback drainage; we have thermal runaway and off to Venus.
    Well not really. This is a clamped system; and that water will only rise, until it starts overflowing the sink edge; and you get precipitation on the kitchen floor. A totally non linear event has interfered with out nice competing feedbacks in the kitchen sink. Adn that water isn’t going to rise appreciably above the edge of the klitchen sink; no matter how much positive feedback we have.

    In the real world atmospheric scenario the edge of the kitchen sink, is at +22 deg C; and the name we use for that edge is CLOUDS !

    Only H2O of all the GHG Species exists permanently in the atmosphere in all three phases; vapor, liquid, and solid; and in the latter two phases it forms clouds; which block large amounts of solar energy from reaching the surface.

    Who wants to go to their grave having wasted their life looking for a cloud where it got hotter in the shadow zone when the cloud passed in front of the sun. It doesn’t happen.
    More clouds (over a climatically meaning ful time (30yrs)) is ALWAYS negative feedback clamping of the maximum possible earth Temperature.

    So it’s that simple; and you can add bells and whistles to make it a lot more complicated; but it still boils down to cloud modulation. IT’S THE WATER !

    Sorry to use up your space Dr Roy.

  20. Steve Koch says:

    Roy,

    I’m a big fan of your work. If you look at climate trends for cities across America (which I’ve done quite a bit), the trends are always that the humidity is higher in the morning coolness and then gets lower in the warmer afternoon. Does that mean anything re: temp effect on humidity? I realize that maybe higher temps drive the water vapor to higher altitudes so that the amount of water vapor at low altitudes (maybe where the humidity sensors are located) is reduced.

  21. Julian Flood says:

    quote
    I was talking about *changes* in precipitation processes as a result of warming.
    unquote

    Warming is not the only agent forcing precipitation changes. Reductions in the number of, and changes in the type of CCNs will also have an effect. The Kreigesmarine effect will reduce the number of salt particles and DMS production must have reduced as plankton poplations fall. The aerosol population will now have many fewer hygroscopic CCNs.

    The two big cooling processes are stratocumulus reflection of incoming shortwave and convective heat pump emission of longwave radiation from high enough to circumvent the greenhouse effect. Both of these will be altered by aerosol changes: stratocumulus thickness will reduce as fewer CCNs lead to larger droplet size and reduced opacity; the convection which leads to cumulus and cumulonimbus formation will trigger less readily, at the margin, when the initial condensation which starts the process begins at a higher relative humidity. (see Kulmala 1997 The Effect of Hygroscopicity on Cloud Droplet Formation)

    I have seen no quantitative descriptions of either, but Latham and Salter’s cloud ship research may be of use in the former case and a handwave assessment may be found in the satellite images of the Gulf oilspill — downwind of the spill my (admittedly biased) eye can see the stratocu cloud fading away. It is a shame that no research was carried out on aerosol numbers over the spill.

    So, one effect disrupting both cooling processes, an effect which will have been operating since the early twentieth century or before, perhaps even in 1850 when the petrochemical industry began. Occam’s razor anyone?

    JF

  22. John Galt says:

    Dr. Spencer,I wonder if we could get you to comment on the latent heat effect of the water cycle. As water evaporates from the surface, it carries latent heat with it, cooling the surface. Convective transport of this water vapor to higher altitudes effectively moves that energy around the greenhouse effect. When that vapor condenses, it not only removes the vapor, but emits that stored latent heat at a higher altitude, bypassing much of the greenhouse effect. If higher temperatures drive more evaporation and precipitation, then they also drive greater convective transport of latent heat. It would seem to me that the evaporation of water into the atmosphere is a positive radiative feedback, for however long it remains there. The evaporation/precipitation cycle is then a negative convective feedback, independant of the cycle time. As surface warming drives more evaporation,the cycle time should shorten, there should be more precipitation, more often. This should then drive the total feedback effect in the negative direction. Considering that the latent heat of water is huge, this effect seems significent to me.

  23. Julian Flood says:
    September 16, 2010 at 12:08 AM

    “So, one effect disrupting both cooling processes, an effect which will have been operating since the early twentieth century or before, perhaps even in 1850 when the petrochemical industry began. Occam’s razor anyone?”

    According to the Bureau of Meteorology, precipitation over Australia increased over the C20th. What are the figures from other continents and oceans?

    Empirical evidence anyone?

  24. ClimateWatcher says:

    I would like to offer two other reasons:

    6.) Subsidence

    For a given GHG, the radiative effects are due to:
    A.) the profile of the constituent ( how it varies with height)
    and
    B.) the profile of temperature

    In the homosphere, CO2 is well mixed, so the cooling rate
    appears to peak at the top of the homosphere (~ 1mb) where
    CO2 diminishes rapidly with height as seen here:

    http://www.aer.com/images/rc/lbl_clrt_mls.gif

    within the homosphere the cooling rates seem to
    vary more with temperature (indeed warming at
    the base of the tropopause inversion).

    Water vapor, on the other hand is not well mixed,
    but diminishes with height, on average, through the
    troposphere. Combined with the normal lapse rate
    of the troposphere, this leads to a peak cooling
    due to water vapor in the upper tropopause.

    Were water vapor to increase within the
    troposphere, but not the stratosphere,
    which would be consistent with AGW GCMs,
    the cooling rate of the upper troposphere
    would necessarily increase.

    And radiative cooling in the upper troposphere is
    what leads to subsidence:

    http://davidsmith1.files.wordpress.com/2008/06/0615081.jpg

    Subsidence accomplishes an important negative
    feedback to increased water vapor
    by leading to drier air over more humid air.
    This increases the emissivity to space because
    the water vapor from the base of the subsidence
    is emitting at a higher temperature than if
    the moist air had not subsided.
    (Indeed the signature of a subsidence inversion
    on a SkewT chart is divergent temperature and
    dewpoint traces. )

    7.) The General Circulation

    Dessler’s papers seem to focus on variation of tropical
    water vapor with respect to short term El Ninos.
    One of the problems with this analysis is that
    tropical and indeed global water vapor is dominated
    by the ITCZ. And the ITCZ represents the convergence
    of the general circulation originating from opposite
    polar air masses. Thus, and intensification of the
    general circulation by increased polar cooling,
    can bring about increased convergence at the ITCZ,
    and so increase upward transport of water vapor.

    Both of these processes, Subsidence and the General
    Circulation, are dynamic modifiers.
    Evaporation, after all, acts at the surface, over water.
    Motions which counter the transport upward and
    outward from that point can revert tendencies
    toward increased water vapor.

    • You cannot increase subsidence without also increasing ascent somewhere else. And ascending air increases the humidity of the middle and upper troposphere.

      So, one cannot argue whether water vapor feedback is positive OR negative based upon subsidence regions (sinking air) or ascending regions, because they on average have offsetting effects. It’s how the humidity of the whole circulation changes, which is then a function of other processes — mostly precipitation efficiency.

  25. Julian Flood says:

    quote
    According to the Bureau of Meteorology, precipitation over Australia increased over the C20th. What are the figures from other continents and oceans?
    unquote

    I can see scenarios where changes in aerosol types might well lead to increased precipitation and thus reduced albedo — I’ve lost a coupe of papers which compare the condensation resulting from a mix of three types of CCN and the graphs are anything but simple. Gosh, Ghosh? I’ll have a look. I’m not entirely sure about fewer CCNs leading to less precipitation either — I’ve seen a mention of bigger droplet size caused by fewer CCNs scavenging more of the water vapour which, all things being equal,might well cause the larger droplets to reach a critical mass.

    Have a look at the uncertainties in that block graph by the IPCC. Clouds and aerosols, critical areas and tens of millions should be thrown at them. I wonder what the VOCALS results have turned up.

    I’m pleased you stress the importance of empirical evidence — climate science is full of models. If I could have a granted wish I’d like to see albedo measured properly over an extended period — Palle/s work, great though it is, carries too big a burden.

    JF

  26. Frank says:

    Dr. Spencer: Your post on water vapor feedback gives me the opportunity to ask a question that hasn’t been answered by discussions (at SciencofDoom) of Ramanathan pioneering 1989 paper (Nature 342, 758-761). The analysis done in his paper shows that the combined water vapor/lapse rate feedback (dG/dT) was strongly positive IN CLEAR SKIES in 1988. If valid, many scientists should have tried to repeat this seminal analysis for different time periods and with different instruments. Unfortunately, Ramanathan didn’t mention any supporting studies in a 2006 book chapter reviewing this work and we haven’t identified any such publications. One hypothesis is that a tight linear relationship between G in clear skies and T_s is an unusual occurrence that doesn’t last for very long. A second hypothesis is that the results are sensitive to methods for distinguishing between clear and cloudy locations. What is the current range of views about this publication and this type of analysis?

    You and others currently analyze the relationship between G and T without breaking the data up into clear and cloudy skies. Your plots are much noisier than Ramanathan’s – possibly because clouds vary substantially with time – but they do reflect all of the important feedbacks. However, if you only want to know about water vapor/lapse rate feedback, Ramanathan’s approach could avoid difficulties with noise. Unfortunately, selecting clear skies does bias the data towards regions with dry subsiding air where small increases in the quantity of water vapor result in a large percentage change in water vapor and therefore a large change in absorption.

    • Frank-
      Raval and Ramanathan’s 1989 paper was long ago criticized for the mistaken assumption that water vapor feedback can be inferred from the difference between the ascending and descending branches of atmospheric circulation systems. It cannot.

      Feedback must instead be evaluated as the area- average response of the entire circulation system to a temperature change. I know of no one who accepts that the R&R89 paper demonstrates positive water vapor feedback…(although I’m sure there must be a few).
      -Roy

      • Frank says:

        Thank you for your reply. WIth 291 citations, it was hard to find critical responses and be sure that the approach had really been abandoned.

        Having a reliable estimate of WV feedback for whatever-fraction-of-the-sky-is-clear presumably would be of some value. We aren’t blessed with data that have as a little scatter as the results in this paper. Does the approach have any value for assessing clear-sky feedback?

  27. Andrew says:

    Frank-

    With regard to your last paragraph, you might be able to estimate the WV feedback from clear-sky data, but Iff (if and only if) WV was going to behave qualitatively the same in cloudy regions as clear regions and you had no reason to expect that the cloudy regions would expand or contract, thus impacting the estimate of feedback from the clear regions alone, which by it’s nature requires that the coverage of cloudy and clear regions remains the same.

    Those assumptions are almost certainly not valid, IMAO. But besides that, I don’t think that the issue of what causes the total feedback is all that extremely interesting. Except for predicting how the diurnal range would be effected, the temperature changes would scale the same from feedback due to clouds or WV if their magnitudes were the same.

    ~Andrew

    • Anonymous says:

      Andrew: Roy’s reply immediately consolidated my formerly vague ideas about why it is improper to assume that water vapor/lapse rate feedback in clear skies demonstrates anything useful about that feedback on a global scale. Now, I’m asking if R&R’s approach gives reliable information about feedback in clear skies. Changing cloud cover is an obvious problem, but the analysis automatically comes with the data needed to properly interpret it. (Feedback X1 from Y1% of the sky in 1988, Feedback X2 from Y2% of the sky in 1989, etc.) There may be monthly changes in % global cloud cover and R&R used average monthly data. There are certainly daily changes in cloud cover. Some locations frequently contribute to the signal from clear sky, some locations rarely contribute. Should one plot vs the global Ts, or weight local temperature data by the % clear skies. I’m not positive the concept of a clear-sky WV feedback is really meaningful or useful.

      None of these complications would be worth thinking about except for one factor. The tight correlation in R&R’s 1988 data provide one feedback number that we have measured accurately. (Look at the paper.) The fact that no one appears to have followed up R&R’s method – for clear skies only – suggests to me that: 1) there are additional problems with the approach or 2) similarly tight correlations could not be obtained from other data sets.

  28. Fred says:

    Another one to consider.

    As increased CO2 causes atmospheric warming and warmer air causes more liquid surface water to turn into water vapor, then that action – moving from the liquid mid-energy state of H20 to the high, vapor energy state of H20, requires energy, energy that comes from the atmosphere, thus creating a negative feedback loop and cooling the atmosphere where the energy came from.

  29. pochas says:

    Dr Spencer,

    Without convection, the surface of this earth would be searing hot. This is a point you have made in this blog, and it is an important one. After I read your comment about no-feedback warming from greenhouse gasses (60 deg C) I did some back-of-the envelope calculations of my own, and got an even hotter result. This convinces me (if I needed convincing) that convection reduces the surface temperature increment from greenhouse effect from your 60 deg C to the observed 30 deg C, which is in line with Lindzen’s feedback factor of about negative 1.

    Its not all about radiation, though radiation is important. Climate scientists seem to fixate on radiation and ignore thermodynamics. They are dealing with only half of the problem.

    • historically it is true there has been an overemphasis on the details of the radiation, and not enough detail and complexity for the thermodynamics. Of course, there is an interplay between the two, but climate change researchers tend to view the thermodynamics in too simplistic terms. I have mentioned this on many occasions.

  30. ClimateWatcher says:

    In another forum I cited the Paltridge paper and the
    drying aloft.

    Another participant cited a recent paper by Dessler:

    http://www.agu.org/journals/pip/jd/2010JD014192-pip.pdf

    What is your assessment of the other analyses which
    tend to validate increasing absolute humidity?

    • I guess sometimes I assume too much…like assuming that those who ask me questions read my blog. I guess repeating myself goes with the territory. :)

      The short answer is this: There are a number of mechanisms which can cause humidity to increase, which then leads to warming through a stronger greenhouse effect. This gives the illusion of positive feedback, even if feedback is negative. This is one of the main points of our new JGR paper.

      It’s a cause-versus-effect issue that has been essentially ignored in researchers’ studies of feedback, including Dessler’s feedback paper.

  31. Carl.Weis says:

    I find that in the discussion of positive feedback of water vapour it is always assumed that the initial heating is due to CO2 ( which then causes inceased evaporation out of the oceans with increased greenhouse effect etc.. ).
    According to this model ANY change of temperature ( not only the one caused by CO2 ) must initiate the feedback-induced temperature change. Thus CO2 would only be one of an infinite number of mechanisms causing the temperature change by feedback.
    Also it is rarely mentioned that the suggested positive feedback amplifies POSITIVE as well as NEGATIVE temperature change. The consequence of this model of positive feedback is that the temperature should instantaneously EXPLODE unpredictably either to positive OR NEGATIVE temperatures, since small fluctuations of temperature are occurring at any time.
    Such explosion has never happened over the last few millon years.
    Is that not sufficient evidence that the feedback is negative ( clouds! ) ?

    • yes, you are correct, feedback occurs in response to any temperature change, no matter the cause. And yes, it amplifies both warming and cooling. But positive feedback in climate doesn’t mean what it does in other disciplines. All of the IPCC climate models are still stable to perturbations. They are stabilized by the “Planck effect”, that is, how IR intensity increases with temperature (sigma*T**4).

      Positive feedbacks would have to be strong enough to overcome that stabilizing effect in order for the climate system (or a climate model) to be inherently unstable to perturbations. None of the IPCC models are, though.

      • Anonymous says:

        Reply to Spencer sept 17 9.56 AM
        Thanks for your answer.
        May I ask again? ( I am physicist but not familiar with climate models )
        If I understand correctly, the statement: the IPCC models are still stable, due to the T^4 dependence, means that the overall feedback ( product of gain due to water vapour and
        damping due to T^4 ) is still negative. How should then the
        small increase due to CO2 be amplified to a much larger (and finite) value? As the overall feedback ist still negative the effect of CO2 should not be amplified but eliminated.
        Further, a finite amplification in feedback systems is only possible with nonlinear feedback. Which mechanism is supposedly providing the nonlinearity of the feedback?

        C.O.Weiss

        • Anonymous says:

          Christopher Game replying to the comment of C.O.Weiss posted September 19, 2010 at 2:57 AM.

          Dear C.O.Weiss,

          May I offer my answer to your question:
          “Further, a finite amplification in feedback systems is only possible with nonlinear feedback. Which mechanism is supposedly providing the nonlinearity of the feedback?”

          The word ‘amplification’ as used by the IPCC formalism is just a trick. No real amplification occurs in the technical sense of the word ‘amplification’.

          It’s just that the word sounds dramatic and gives specious impression of technical validity; that is to say the word ‘amplification’ here is a piece of IPCC-speak, a piece of political propaganda, not a scientific term.

          The IPCC formalism is not a properly constructed dynamical model as it speciously seems to claim. It is a travesty of the Bode (1945) theory for the design of negative feedback amplifiers.

          When the IPCC-speakers talk of ‘amplification’ they are cleverly mixing a kind of ordinary language use of the word with the proper technical use of the word. Amplification for Bode included real power gain as part of its meaning. The power gain of Bode required the presence of an auxiliary power source to supply energy to the thermionic valves that were the active devices of his amplifiers. Such an auxiliary power source might be supplied by a battery or by a DC power supply. Of course there is no such thing in the atmosphere.

          IPCC-speak glosses over the absence of a proper representation of time or phase delays in the IPCC formalism. In this way, IPCC-speakers pass off phase delay as “amplification”. A step input signal has a phase delay before its full output is reached. Thus a time or phase delay can be, in loose ordinary language, appear as “amplification”, when there is no power gain to justify the technical use of the word ‘amplification’.

          You write of a need for “nonlinear feedback”. I am guessing that you will accept the presence of an auxiliary power supply as one form of the nonlinear feedback that you refer to?

          You also write:
          “As the overall feedback ist still negative the effect of CO2 should not be amplified but eliminated.”

          I think that in order to entirely eliminate the CO2 effect as time passes, while the perturbing CO2 increment is still held fixed and active, one would need some restriction on the system dynamics, such as that only the time derivative of the perturbation should actually drive the system – a kind of AC coupling.

          It is true that over the centuries added CO2 will form geological products such as calcium and magnesium carbonates. I think that there will be residual effects of CO2 on the system as a whole, but that does not necessarily mean that there will be residual effects on surface temperature. For example, in the longer term, more CO2 in the system will enhance forest growth and food crop growth. We will likely need the latter if the apparent current warning of the sunspots is actualized, that we are now facing a couple of decades of dangerously cold weather. It may perhaps be that we will need to deal with this likely coming cold weather by bringing forward the use of nuclear power.

          Yours sincerely,

          Christopher Game

          • Anonymous says:

            Thanks for the comment, of which I do not understand everything:

            My questions relate to my simple view:
            The stated mechanism of magnifying the small temperature increase due to CO2 is that increased temperature will increase water vapour content of the atmosphere, which leads to further temperature increase.. etc in a feedback loop. This effect certainly exists. (And this official suggestion really marks water, and not at all CO2, as the “dangerous greenhouse gas”.) The question ( as we all know ) is: is the effect of water vapour increase a rise or a fall in temperature ( the latter presumably by clouds )?
            These two cases I see as positive or negative “feedback”.

            Were the feedback postive, we should expect “runaway” unpredictably either positive or negative.
            That has not happened (!) and the claim is for a FINITE magnification of the temperature increase due to CO2, not runaway.
            As far as my knowledge of feedback systems goes, such finite amplification can only occur in a feedback system with NONLINEAR gain ( meaning that the feedback mechnism is softly turned off as the variable in question ( here temperature )increases in the feedback process.
            Such systems are known in electronics as ” regenerative amplifiers “. I know them from my laser physics research, where the optical gain is “saturable” ( essentially due to
            the limited input through the pump mechanism ).
            Thus my question: what mechanism is officially described which would bring about the necessary “gain saturation” or the “nonlinearity of the feedback”??
            My other question was: if there is “negative feedback” due to Stefan-Boltzmann ( sigma T^4), and the positive feedback in the IPCC models (due to water vapour ) does NOT overcompensate the T^4 effect, ( as Roy stated in his reply to my first post: “IPCC are stable against perturbations” ),
            how can there be a magnification of a temperature change ?

            In short I see a finite magnification in a feedback system only possible for a system with nonlinear ( “saturable”) gain. I do not see where the nonlinearity or saturability of the feedback in the IPCC models should come from.

            If you have an answer: thanks in advance

            Carl

          • Carl:
            I now see your confusion. In climate, “feedback” means something different. In the most common sense of the word feedback (from engineering, electronics, etc.), the TOTAL feedback is negative, even in the models producing strong warming.

            It’s the individual components that make up the total feedback than can make the total feedback “more negative” (which would be a negative feedback), or “less negative” (which would be a positive feedback in the climate sense of the word).

          • Anonymous says:

            Roy,
            Thanks again for your comments.
            I guess what I call “nonblinear feedback” is provided by the combined effects of several processes ( e.g. as you suggest water evaporation and T^4 energy loss. The T^4 seems sufficiently nonlinear.. )
            I thus get the idea of what is the nonlinearity I was looking for..
            Thanks again for sacrificing your time to clarify things for a non-specialist..

            Carl

          • Anonymous says:

            In response to Roy’s clarification to Carl on September 20 that overall or total feedback is negative, well, yeah, if it weren’t, we wouldn’t be here –earth would be fried or frozen. What gives me a headache is whenever climate scientists search for forcings (like AGW) to explain rises, dips or wiggles in temperature cycles, rainfall patterns, cloud cover extant, etc., when overshoot, ringing and oscillation, characteristics of negative feedback systems’ response to changing signals, are contributing to the wiggles. And these instabilities arise because of delays and hysteresis. Remember Roy’s feedback diagrams showing temperature changes relative to radiation fluxes? The displacement of Roy’s stripes (slopes) is a consequence of earth’s memory, i.e. sea surface maximum temperatures lag air temp by a month, or changes in polar albedo follow longer term temp changes – lots of possibilities which, in aggregate, bend, split and spiral what we would like to be a single, linear slope.
            Can I give a simple example? I know that we don’t like using electronic amplifiers as an analogy for earth’s climate feedback, but how about a household thermostat as an example of negative feedback?
            We’ll build an insulated house in a frozen desert. It has a furnace that if left running constantly (no thermostat, just an “on” switch) would allow the house to achieve equilibrium with heat loss at140 degrees F. inside. The house is earth and the furnace is greenhouse warming. Let’s wire a thermostat. On earth, the thermostat comes from the presence of liquid water on our planet’s surface. We’ll set the thermostat at, say, 59 degrees. What happens?
            To see what happens, we’ll record temperatures continually. (Our house even has a meteorologist to record the temp’s!)
            If we look closely, we’ll see that the temperature never remains constant, that it is always increasing or decreasing in a sinuous wave. The furnace doesn’t kick in until the temp reaches 58 degrees (hysteresis) and because it takes awhile to heat the house, the furnace doesn’t shut off until 60 degrees. The temperature is constantly changing without any change to the system; in fact, it is a characteristic of the system! Now, what happens to the temp inside if it heats up outside, or if it cools down at night? Not much happens to the maximum and minimum inside but – here’s the cool part – the frequency and shape of the cycle changes. Do you see that the period between peaks decreases as delta temp increases? The temp before the furnace kicks in falls quicker because the house loses heat quicker; recovery when the furnace is running comes slower, though. So the curve isn’t a sine wave but saw-toothed. How about those temp patterns during glacial times when earth’s climate was way less stable than today? Our analogy’s patterns look like that.
            One last thing: the gain of some of the electronic audio amplifiers that I build as a hobby is for the most part set by the feedback (factor). Changing the gain or sensitivity of stages within the feedback loop has limited impact on the amplifier’s overall sensitivity because increasing gain also increases the effectiveness of the feedback. Kapish? Now, this is true of a system with high open loop gain; the earth’s is low. But still, it suggests that feedback will mitigate changes due to forcings – at least until it breaks into oscillation and we have another glacial period!

          • Anonymous says:

            Christopher Game replying to Carl.Wies’s post of September 20, 2010 at 4:08 AM.

            Dear Carl,

            The word feedback is sometimes a part of the ordinary language. As such it is rather vague. For example, it might be said that this submission that I am now writing was ‘feedback’ to you on your post. But I don’t think you would try to calculate the loopgain for it!

            The word ‘feedback’ as used by Bode in his 1945 book on the design of negative feedback amplifiers (as cited for example by Hansen, Lacis, Russell, Stone, Fung, Ruedy, and Lerner (1984) at IRN1263184X and by Bony et al. (2006) at J. Clim. 19: 3445-3482) is carefully defined over several chapters. The definition is not child’s play. It is specially constructed to make it easy to design an electronic amplifier. The reasons for the construct are clarified by E.H. Nordholt in Design of High-Performance Negative-Feedback Amplifiers, Elsevier, Amsterdam, 1983, ISBN0444421408. Briefly, the reasons are that an accurate amplifier is most easily designed by making the loopgain as large as possible (on the order of magnitude perhaps of 100) and the immittances of wastage from the signal path as small as possible, all in just one feedback loop as carefully defined. These factors make for the Bode theory to be a good approximation to the actual circuit performance; when these factors do not hold, the approximation will not be safe. The climate system was not designed to have just one feedback loop with the largest possible loopgain and it was not designed to have small wastage immittances; it is therefore not like a negative feedback amplifier.

            The choice to use a theory from electronics as a formalism for the climate process was not a happy one. It involves forcing things into shapes they do not naturally take. Like Procrustes and his one-size-fits-all bed.

            If one uses the word feedback equivocating between ordinary language and Bode’s technical sense, one must run into endless logical problems: and so it happens. If one is loose in using the words, one can expect puzzlement to follow; picoseconds saved by a loose writer of words leads to hours of lost time for the reader.

            There is another general way of thinking in strict technical terms about feedback, without actually using the word feedback in a narrowly defined technical sense. This is the way of the theory of dynamical systems. They are loosely and valuably described as ‘feedback’ systems, but the word ‘feedback’ is not used explicitly in their study.

            Work of this kind was set well on its way by Poincaré. More recent studies include Birkhoff’s Dynamical System (1927/1991) ISBN 082181009X, Andronov, Leontovich, Gordon, and Maier’s Theory of Bifurcations of Dynamic Systems on a Plane, (1973) ISBN 0706510631, Abraham and Shaw’s (2nd edition 1992) Dynamics. The Geometry of Behavior, Addison-Wesley, Redwood City CA, and others. In this theory one can think of the system with its driver function frozen at a fixed value, then, if there is a fixed point, linearize the evolution equations, and find the eigenvalues of the rate constant matrix. When all the eigenvalues have negative real parts, the system is stable and can be said to show “negative feedback”. Other possibilities arise, of course. There may be no fixed point near the present location of the system in phase space.

            You write: “Thus my question: what mechanism is officially described which would bring about the necessary “gain saturation” or the “nonlinearity of the feedback”??”

            The officials do not bother to answer such questions. Why would they? The word “amplification” has done its propaganda work; why cloud the picture with scientific accuracy? Non-officials might be forgiven for asking that the question be posed in terminology that has a canonically defined meaning.

            You write: “Were the feedback postive, we should expect “runaway” unpredictably either positive or negative.”

            I think Dr Spencer has succinctly answered this in his post of September 20, 2010 at 10:09 AM.

            You also write: “how can there be a magnification of a temperature change ?”

            You are now speaking of “magnification” when previously you spoke of “amplification”. It is not just a matter of words; it is a matter of the underlying concepts. The alleged ‘increase in temperature’ is due to alleged delay in the escape of energy from the earth. When the alleged ‘increase in energy supply’ persists, the alleged delay in escape leads to alleged accumulation of energy within the system, and this appears as alleged increase in temperature. There is no need to think of nonlinearity to account for this, and no need for an auxiliary power supply. It is simply explained by the ‘bucket analogy’ mentioned under this blog article in my post of September 14, 2010 at 3:29 PM. There is no amplification, and no magnification in the sense that might allude to amplification. The use of the word “amplification” in IPCC-speak is simply a trick.

            This is not to say that the climate process is linear. The (linear) bucket analogy is not a good one from a scientific viewpoint, but it works a treat as a propaganda device.

            To get a general understanding of things, I think it best to use the canonical formalisms of the theory of dynamical systems as mentioned above. ‘Short cuts’ about this usually do not save time, but take longer to get the desired understanding.

            For useful understanding when using the word ‘feedback’, one must precisely state the model within which one is using it.

            Yours sincerely,

            Christopher Game

        • Anonymous says:

          Christopher Game further replying to Carl.Weis’s post of September 20, 2010 at 4:08 AM.

          Dear Carl,

          May I offer some comments intended to relate the electronic amplifier design theory of Bode (1945)to your field of laser research. I hope my ignorance of the latter will not matter too much for the present purpose; if so, you will perhaps tell me.

          I would like to define an amplifier. It is a device that has three conceptually if not physically independent power sources, the signal source, the biasing power supply, and the amplificatory power supply. The biasing power supply puts the device into a state in which it can act as an amplfier. The signal source is considered to be driven independently of the operator’s options, and is truly independent of the biasing and the amplficatory power supplies. The amplificatory power supply is set up so that it can add power to the signal that the amplifier receives from the signal source, so as to produce a signal output which is delivered to some load device. The signal output must more or less quickly and linearly and accurately and quietly convey the information in the source signal, but at greater power than the source signal power.

          The biasing power supply is regulated by some stable negative feedback arrangement that ensures that the biasing of the device is unchanging with time. For example the collector of a common emitter coupled transistor is best driven by a regulated constant current source, while the emitter is best driven by a constant voltage source. These time-independences, characterizing the biasing circuitry, are the physical meaning of the idea of a dynamical fixed point for the device; when the signal is steadily zero, the output goes to zero. In an electronic amplifier the biasing power can be supplied by batteries, for example. For a laser, the ‘biasing circuitry’ is represented, as I understand it (perhaps mistakenly?) by a ‘pump’. This is only one of the functions of the ‘pump’.

          The amplificatory power supply is able to provide large rapid changes of power to the ‘active’ circuit element. These rapid changes of power are made to respond so as to transmit the signal information. In an electronic amplifier, this power may be supplied by the same batteries that supply the biasing, but it has a different function. It is not intended to be time-independent, but is intended to provide the power for the gain of the amplifier, to be dictated by the signal source. In a laser the power for the gain of the signal is also supplied by the ‘pump’ (his is the other function of the ‘pump’; please correct me if I am mistaken here). The pump is capable of supplying changing power as dictated by the changes in the signal source.

          According to Bode (1945), “We are accustomed to thinking of feedback amplifiers as being either regenerative, in which case the external gain is increased at the cost of an increase in the effects of tube variations, or degenerative, in which case the gain is reduced in exchange for a corresponding improvement in the effects of tube variations.” The same applies to transistor amplifiers. Regeneration means, roughly, positive feedback with loopgain less than 1, verging into nonlinear modes of operation. For accurate amplification, it is strenuously to be avoided, except in the most special circumstances. Degeneration means controlled negative feedback, and its great usefulness was the discovery of H.S. Black in 1927 and was patented in 1934. Its usefulness is to make the amplifier less noisy, more linear, and more accurate.

          May I suggest to you that the nonlinearity about which you write is conveniently analysed as telling about what time-invariant biasing pumping is needed to bring the device to a suitable operating point. The actual amplification, if that is what the laser is being used for, is more or less linear and is a matter of power gain supplied also by the pump, but this time by its capacity to provide rapidly changing power, responsive to the signal.

          The climate system as represented in the IPCC formalism has no biasing power supply and no amplificatory power supply. It has only the signal power supply, which is the insolation, and which hardly varies on the climatic time scale; of course it varies very importantly on the day-night time scale, which variation is studiously ignored by the IPCC formalism. This is at a remote extreme from the amplifier situation. In the amplifier situation, the signal source is small and lacks power. That’s why one needs to amplify it. In the climate system the signal source is the one and only massive power of the insolation; there is no other power supply; and the signal is hardly of interest. For climate work, the utter inappropriateness of the Bode amplifier theory is apparent in this. The IPCC formalism is metaphorical in that it treats the CO2 changes as if they can be seen as changes in signal power, when in terms of Bode’s theory they would naturally be seen as changes in the properties of the parasitic passive immittances. The climate process, physically considered, is a dissipative process, the very opposite of the kind of process considered by Bode whose work the IPCC formalism cites. The climate process naturally evolves and maintains its own dissipative structure, while an amplifier is carefully designed as an artefact with a purpose in mind.

          In a nutshell, I am saying here that the nonlinearity of which you speak is dealt with by the time-independent biasing power supply, not by the rapidly-time-varying amplificatory power supply, which is what does the amplifying, accurately supplying the power gain which characterizes an amplifier. Perhaps I am way off beam here, and my analogy between electronic and laser amplification is muddled?

          Yours sincerely,

          Christopher Game

          • Anonymous says:

            Is seems to me that the negative feedback amplifier is not an analog of the climate system. The former has two inputs,
            positive for the signal, and negative for the feedback which is connected to the output through a voltage divider.
            I do not see the analog of the two inputs nor the analog for the voltage divider ( which together determine the finite well defined value of the gain ) in the climate system.
            On the other hand, the statement which one usually hears: temperature increase causes evaporation which leads to further temperature increase etc.. certainly describes a feedback system; with positive or negative feedback ( mathematically given by positive or negative Lyapunov exponents in the linear stability analysis that you have described ). The IPCC states that the Lyapunov exponent is positive.
            This model leads to runaway for positive Lyapunov exponent. Therefore to provide FINITE amplification as stated by IPCC( or magnification, I do not see a difference between the two in this context ) a “gain saturation” in laser parlance is necessary. ( mathematically a decrease of Lyapunov exponent with increasing temperature ).
            For this latter I do not know the mechanism which the IPCC would put forward. And I would like to know their argument for this “gain saturation” in terms of a mechanism.
            My impression is not that the argumentation of IPCC is overt nonsense. I found in the past that they usually bring up arguments and explanations which at first sight seem plausible, and so are good enough for the public. But I have not generally seen OVERTLY self-contradictory arguments.
            Of course for a physicist the inconsistencies of the claims are apparent.
            As you may see, I am trying to understand the argumentation of IPCC in oder to be able to finger-point to the faults..

            Carl

        • Anonymous says:

          Just to confuse matters even more: Where does the energy come from to result in the feedback amplification? In electronic feedback we basically have unlimited energy from the power outlet. In climate science the only source of energy is the solar insolation source of the photons that get absorbed. It is my claim that ALL of the absorbable photons do get absorbed leaving excess GHGs in the air (or in the case of Water Vapor, excess in the ocean. IF ALL the photons are absorbed at any given instance of time then you can’t absorb any more even when you add more CO2 or water vapor GHG. Feedback increases are NOT possible.

          John Dodds (see more comments below)

          • Anonymous says:

            Christopher Game replying to John Dodds’ comment of September 21, 2010 at 8:52 AM.

            Dear John Dodds,

            In general I agree that the energy sources need to be stated clearly, as you emphasize. But as a detail, we may regard cloud formation as internal to the climate system and so as part of its responses, including being able to change the amount of absorbed solar energy. Clouds are good reflectors of sunlight. So ‘feedback’, subject to a more precise definition of a model, affects the amount of absorbed solar energy.

            Yours sincerely,

            Christopher Game

  32. Christopher Game says:

    Christopher Game responding to Carl.Weis and Dr Spencer’s posts of September 17, 2010 at 9:50 AM and at 9:56 AM.

    It is good to see the distinction being made here between different senses of the term ‘positive feedback’.

    What in the IPCC “forcings and feedbacks” formalism is called a ‘positive (or negative) feedback’ would in other disciplines be referred to as ‘positive (or negative) contribution to overall feedback’.

    The distinction between ‘positive’ and ‘negative’ overall feedback makes physical sense only when there is a dynamically fixed point for reference. Without a dynamically fixed point it makes sense to speak of ‘feedback’ but not to try to distinguish whether it is positive or negative. For example, in the basin of attraction of a strange attractor which governs a deterministic chaotic régime, feedback in general is a useful concept, but it cannot be characterized as ‘positive’ or ‘negative’; that is why it is called chaotic.

    The ‘Planck response’ is distinguished in the IPCC formalism because that formalism is based on Bode’s (1945) book about the design of negative feedback electronic amplifiers. Bode’s theory for that purpose assumed that it would be always convenient to use a “reference variable”, partly defined on page 49 of Bode’s book. Roughly speaking, the “reference variable” of Bode was arbitrarily chosen by the investigator for the electronic circuit of interest. It was the Fourier or Laplace domain transfer function of the chosen active device of immediate interest, such as the valve of interest in Bode’s day, or the relevant transistor or transistor combination, such as a ‘cascode’, today. Bode’s terminology and theory required a such a ‘forward gain’ circuit element, with respect to which one could specify a definite loop that would contain also the feedback linkage.

    The Bode amplifier had a fixed point, governed by a definite dynamical law, either for the case of an AC coupled amplifier, which had a zero output for a constant input, or in the case of a DC coupled amplifier, which had a definite steady zero output, possibly with a steady zero offset, for a zero input. Such a definite fixed point, set by definite dynamical laws, is not available for the climate system as represented by the IPCC “forcings and feedbacks” formalism. That formalism simply relies on the steady-state assumption, which is not based on a definite dynamical law.

    In the formative days (early 1980s) of the IPCC formalism, the virtual direct no-feedback warming of the atmosphere, resulting from the virtual direct no-feedback increase in infrared opacity due to CO2 increment, was considered to relate closely to the Planck radiation from the atmosphere, and that radiation was used to estimate the virtual no-feedback warming. That virtual no-feedback warming was then considered to be taken as the effective ‘reference variable’, a nominal ‘active device’, for the Bode theory. Nowadays, the needed virtual ‘feedforward gain’ element, the virtual warming, is estimated differently, but the original use of the Planck estimate has stuck in the terminology. As a relic of former days, the ‘Planck response’ is now used as a reference feedback contributor with respect to which other feedback contributors are described. This is partly clarified, for example, in Appendix A, at pages 3474-3475 of Bony et al. (2006), Journal of Climate 19: 3445-3482. The IPCC formalism’s ‘feedforward gain’ element is merely nominal, and does not have actual power gain such as belonged to the active devices of Bode’s amplifiers, which had auxiliary power supplies, battteries or other DC power sources.

    Bode’s reference variable was chosen by the investigator, not dictated by the circuit. This emphasizes the point that the IPCC formalism is an arbitrary intellectual artefact of scientists, not a law of nature. This point is noted by Schmidt, Ruedy, Miller, and Lacis (2010) in their draft cited by Dr Spencer in his blog article On the Relative Contribution of Carbon Dioxide to the Earth’s Greenhouse Effect posted September 10th, 2010. They wrote: “Firstly the concepts of forcings and feedbacks … Generally speaking the definitions depend on the modelled system. …. Secondly, the term ‘radiative forcing’ has been used differently by different authors.”

    Christopher Game

  33. R. de Haan says:

    Dr. Spencer,
    What do you think about this presentation from Dr. Ir Noor Van Andel
    http://climategate.nl/wp-content/uploads/2010/09/KNMI_voordracht_VanAndel.pdf

  34. suricat says:

    Dr. Roy.

    Yet again, I get to congratulate you on a fine post. However, I’m still amazed at the way that science treats a functioning device as something to be sectioned into small pieces and explains each tiny piece. Perhaps this is because I’m essentially an engineer that needs to understand the overall mechanism.

    When I look at the evaporation/precipitation mechanism for a column of Earth’s atmosphere I see a unified mechanism. A mechanism that offers almost constant ‘radiative forcing’ with a varying ‘latent thermal’ and ‘convective thermal’ energy transport. In short, I see a ‘long’ evaporative exchanger with a large value of DT (Delta Temperature) as overall thermal differential.

    To my understanding, your current post deals only with the low troposphere. This can be confusing when one realises that a great amount of precipitation within the atmospheric column doesn’t actually reach ‘ground zero’, or even the low troposphere (there’s a word for this type of precipitation, but for the life of me I can’t remember what it’s called). However, for the sake of a usable noun, let’s call this a ‘preferred-relative humidity’ (P-RH).

    P-RH causes a ‘cascade’ of precipitation throughout the atmospheric column due to varying specific humidity within it.

    This dates back to Miskolczi and his assumption that ~’WV ‘takes up the slack” and involves partial pressure. I’ve a few theories on this, but I’ll not bother you with these just now.

    Best regards, Ray Dart.

  35. According to Prof. Ole Humlum’s website total column water vapor column did ***not*** increase (or did even decrease) during the last 10 years. His graph can be found here. Simple inspection of his graph derived from ISCCP project suggest even an overall decline since the start of the graph at 1983.

    • Anonymous says:

      Christopher Game responding to Francis Massen’s post of September 18, 2010 at 1:57 AM.

      Dear Francis Massen,

      Please put up another version of your link to the graph of Prof. Ole Humlum. The present version doesn’t work for me.

      Yours sincerely,

      Christopher Game

  36. Alexander Davidson says:

    I’m coming to the conclusion that the answer might be rather different. It’s because apart for thin clouds, there’s no existing theory or evidence of the cloud part of ‘global dimming’, 44% of AGW [AR4]. So, as the IPCC’s claims of CO2 AGW are far too high, there has to be an alternative source of heating, particularly the oceans.

    The answer is I suspect in the physical optics of clouds [my work, not published]. As well as diffuse scattering there’s probably a powerful geometrical effect at the upper boundary. From 5 micron [polluted] to 15 micron droplets, it increases by c.10. So, polluted clouds will have lower albedo. A fall from 0.7 to 0.6 increases heating by 1/3rd.

    Look at ocean heat capacity: http://bobtisdale.blogspot.com/2010/01/nodc-ocean-heat-content-0-700-meters.html . Rapid heating a few years’ ago scared the AGW crew rigid because the Keeling curve didn’t predict it: http://en.wikipedia.org/wiki/File:Mauna_Loa_Carbon_Dioxide-en.svg

    Now look at World GDP: http://www.google.com/publicdata?ds=wb-wdi&met=ny_gdp_mktp_cd&tdim=true&dl=en&hl=en&q=world+gdp

    Factor recessions into the heat capacity and it’s even better [the recent levelling off is another argument]. It looks to me as if the real heating has been the increase in aerosols from industrialisation rather than the CO2. Since aerosols drop out after 18 months [CO2 a century], less rapid industrialisation will trigger fast cooling.

    So, no need to invent fancy CO2 stuff, the natural feedback we call weather [lowers 60 K theoretical GHG effect to 33 K] will take care of things. AGW could be temporary!

  37. Christopher Game says:

    Christopher Game with another remark about ‘positive’ and ‘negative’ feedback, and why the ‘fixed point’ matters.

    For feedback to have a defined sign, postive or negative, there needs to be a dynamic fixed point about which the feedback is defined. The IPCC formalism doesn’t have a dynamical definition of its merely assumed or merely nominal ‘fixed point’. Without a physical law to supply a dynamic definition, to constitute empirical evidence of feedback with a defined sign, the empirical data must include respective feedback responses separately to both positive and negative perturbations.

    If it were proposed that empirical data since 1973 showed only positive perturbations correlated with positive or anticompensatory responses, this alone would not constitute evidence of ‘positive feedback’. To constitute evidence, the data would also need to show negative perturbations correlated with negative or anticompensatory responses.

    Without both signs of perturbation about a well defined fixed point, empirical records might simply be showing an aspect of a chaotic dynamical process.

    Christopher Game

  38. Bob_FJ says:

    Dr. Roy,

    The K & T “Earth’s Energy Budget” diagram as used in the IPCC’s 2001 & 2007 reports gives global-year averages of energy leaving the surface as:

    Thermals: 14.3%
    Evapotranspiration (E-T): 46.4%
    Radiation (Net) 3.9%…directly to space And; 35.4% absorbed

    Thus surface heat loss to forming clouds and beyond, (non GHE), amounts to about 65%
    Putting aside whether these numbers are real or not, it would seem that the greatest proportion of surface cooling is from E-T, (evaporative cooling/latent heat). Thus, if there is any increase in water vapour that may nominally be a positive feedback, would not E-T be a negative feedback? Since ~46% is such a large proportion of surface cooling, surely a small change in this amount would be significant? Seems like a powerful “thermostat” to me!

    Regards, Bob Fernley-Jones, (engineer retired)

  39. pochas says:

    A discussion of how climate scientists define feedback may be found here:

    http://www.leif.org/EOS/2009GL039628-pip.pdf

    Other disciplines use a different definition that involves “process setpoints.”

  40. Ken Chapman says:

    Dear Dr. Roy,

    Recent data from BBSO’s Earthshine project may add another important term to the equation. The earth’s albedo appears to be far more variable in both the short and long term than previously supposed. The changes in equatorial cloud cover may be the source of the elusive negative feedback mechanism.
    It is an interesting project that, so far, has avoided much of the controversy plaguing other researchers. We need more people that are not so set in their convictions and instead have room to “Waffle”.
    Your candor is refreshing.

  41. Harold Pierce Jr says:

    ClimateWatcher says:
    September 15, 2010 at 2:44 PM

    “In the homosphere, CO2 is well mixed,…”

    As a matter of fact, the GHG’s are not well-mixed on the basis of mass per unit volume.

    High pressure cells have more local mass than do low pressure cells into which mass ususally flows from the high pressure cells.

    Water droplets in clouds have dissoved CO2 which can tranported from one location to another location and be released if the clouds dissipate or deposited on the surface if the clouds release rain.

    The distribution of the mass of the atmosphere alos depends on elevaton. Air in the mountains has less mass than at sea level.

  42. John Dodds says:

    Water Vapor Feedback is an absurd notion.
    There is an excess of Water vapor in the air. Even the GHE puts more unused water vapor into the air every night when the number of available energy photons is decreased and the number of GHE absorbtions is decreased and hence the number of unused excess water vapor molecules increases.
    SO, if there is excess water vapor, just WHY IN HELL would mother nature choose to wait for man to produce CO2 in order to produce warmer temps in order to produce water vapor feedback? Why not just let the outgoing IR photon get absorbed directly by the already existing water vapor in the air?

    It is a fact that there are more excess GHGs in the air than there are absorbable photons, otherwise the GHE would just continue to increase until there was an excess of GHGs OR all the GHGs had been used up & the oceans dried up.
    Therefore it is the number of photons that dictates how much GHE we get, NOT the number of GHGs. Any added GHGs (both WV & CO2) just become EXCESS in the air, since there are no available photons for the excess GHGs to absorb. This invalidates ALL the global warming models and the IPCC conceppt that “more GHGs means more warming”
    See John Dodds paper at http://www.scribd.com, on how “Arrhenius Mis Applied the GHE” to conclude that more GHGs means more warming, instead of how the number of photons dictates how much warming there is.

  43. John Dodds says:

    Some added water vapor thoughts:
    Why is it that when the humidity increases and it rains AND the water vapor GHG doubles or triples, that we do not see an increase in the the local temperature? If the GHG triples shouldn’t the water vapor caused GHE temperature also triple according to “more GHGs means more warming” (AR4, WG1, Ch1, p.116) Since WV causes 75-95% of the 32C GHE why doesn’t tripling the humidity cause a 50C increase in temperature? It seems a little funny that I have never seen that happen!!!

    Since the number of 15um photons that can be absorbed by CO2 is roughly similar to the number of WV absorbable photons, AND yet the number of WV molecules (2-4% or 40,000 ppm) or 100 times as much as 390ppm of CO2, then isn’t it required that there be EXCESS water vapor molecules over those that can be absorbing photons? So adding WV molecules doesn’t add to GHE warming? Now how about CO2? Since more CO2 is released as unused whenever the number of photons decreases everynight, then just how much of the CO2 is unused excess over that required to use up ALL the 15um photons? Isn’t it true that the absorbtion sprectrum for CO2 is 100% saturated- ie if a photon comes in it gets absorbed- which says that there is excess CO2.
    Doesn’t this invalidate the computer models for “more GHGs means more warming” CO2 and water vapor feedback caused global warming?

  44. Mug Wump Wagathon says:

    What is behind the desire to rebrand ‘global warming’ hysteria cum ‘climate change’ hysteria to ‘disastrous global climate disruption’ hysteria? The Answer to that is hiding, somewhere deep in the ocean.

    To understand what is going on, it is helpful to first understand that global warming alarmists must assume that GCMs are correct. Accordingly, when ‘global warming’ stopped years ago that fact had to be ignored. Then it was necessary for the alarmists to play with the numbers but meanwhile even the UHI-corrupted land-based measures ceased being helpful to the alarmists.

    Past declines like the Little Ice Age (LIA) — as well as previous warming periods like the Medieval Warm Period (WMP) — were simply hidden. Then there were attempts to marginalize the scope of these major Earthly events as being simply regional instead of ubiquitous. There never was, of course, any good reason for concealing the actual facts about the LIA and the WMP or any of the other previous cooling and warming periods except that these were inconvenient facts for the global warming alarmists to deal with.

    And, we’ve seen a similar trope with the cooling oceans. We first have ignorance of the cooling and then corruption of the facts to obscure existence of the cooling and then trying to find a reason why the cooling is not significant.

    So now it is largely conceded among those who pretend to any amount of credibility on the subject of global warming that the oceans have been cooling for a decade. And we know that there is no ‘global warming’ during a period in time when the oceans are cooling.

    Since they still cannot abandon GCMs, global warming alarmists must cling to a belief that predicted global warming is still happening but it is hiding. Hence, the Earth is still warming globally but it cannot be detected because the heat that is building up is hidden somewhere deep in the oceans. And, that is what Trenbreth and others are telling us.

    This latest idea of the global warming alarmists has been described as being akin to ‘climate porn.’ The evolution in the AGW hoax and current fearmongering tactics can be summed up very simply. The global warming alarmists are now saying that the warming is real but the heat is hiding — haunting our future — and, when if does finally rise to the surface of the Earth, all hell is gong to break loose. Or, to put it more ‘scientifically’ for consumption by the mainstream media, the global warming alarmists are now predicting ‘disastrous global climate disruption.’

    In other words, the global warming alarmists have given up. They know they cannot make their case. The global warming hoax has evolved to the point now where it has the credibility of earthquake prediction science. The official ‘science’ of the global warming alarmist community is simply to pray for catastrophe and then point. The only real ‘consensus’ that exists, now that Bush is gone, is to simply blame capitalism whatever Nature brings our way.

  45. Christopher Game says:

    Christopher Game replying to Carl.Weis’s post of September 21, 2010 at 12:45 AM.

    Dear Carl,

    You write: “Is seems to me that the negative feedback amplifier is not an analog of the climate system. The former has two inputs, positive for the signal, and negative for the feedback which is connected to the output through a voltage divider.”

    I am glad that we seem to agree that a negative electronic feedback amplifier is not a good analog of the climate system. That is the main point of my comments here.

    But my reasons are different from yours just cited. We are defining our terms differently. I am thinking of a one-sided amplifier, in which one of the terminals of the input port is directly connected to the reference zero terminal; I would say that you are describing what I would call a differential amplifier, in principle having two independent signal energy sources, not just one as in my offered definition. And I am not thinking of including the voltage divider as (an internal) part of the amplifier, but as part of the load, external to the amplifier; some amplifiers are specified to have current output (transadmittance amplifiers, see Nordholt 1983 page 4) or power output, not voltage output. My reasons are concerned with the diverse energy sources of the system. It is the energy flows that are really at stake here. This is an example of the need to specify one’s models.

    You write: “On the other hand, the statement which one usually hears: temperature increase causes evaporation which leads to further temperature increase etc.. certainly describes a feedback system; with positive or negative feedback …”

    Yes, I would accept that as a loose statement that one hears. But I would not say that it “certainly describes a feedback system”. I would just say that it is a loose statement.

    You write: “with positive or negative feedback ( mathematically given by positive or negative Lyapunov exponents in the linear stability analysis that you have described ). The IPCC states that the Lyapunov exponent is positive.”

    I am ignorant of any reference by the IPCC to Lyapunov exponents. Perhaps you will enlighten me. Yes, neutral or non-IPCC people write about IPCC material and mention Lyapunov exponents.

    You write: “As you may see, I am trying to understand the argumentation of IPCC in oder to be able to finger-point to the faults..”

    As wisely prescribed in the mediaeval rules of dialectic, it is a right, proper, and necessary thing to try to understand and state the argumentation of one’s dialectical opponent, as you have been doing. People even write of a ‘principle of ”charity”’ according to which one bends over backwards to make sense of one’s opponent’s argumentation.

    You write: “But I have not generally seen OVERTLY self-contradictory arguments.”

    I think that the use of the Bode theory of electronic amplifiers as analogues of the climate system, cited again in 2006 by Bony et al., is an attempt by the IPCC people to make it seem that they are using a rational basis of argument. But you have written that you think this is not a proper analogy. How far do you intend to bend over backwards?

    I think one can demand more of a dialectical opponent than merely that he avoid OVERT self-contradiction. In physics, one can demand that he present a sound physical argument.

    I think it more useful to try to work on and develop a proper physical theory to deal with the problem at hand than to spend too much time, perhaps a lifetime, trying to make sense of the flawed argumentation of a defender of what you call “inconsistencies of the claims”.

    Yours sincerely,

    Christopher Game

    • Anonymous says:

      I have to thank you for your repeated and thorough comments.
      The reason I am trying to understand the argumentation of the IPCC is
      1) these people are not unintelligent, and maybe one can learn something from them.
      2)exposing your model to the criticism of an opponent is
      the best way to test the solidity of your own reasoning.

      I have a faint idea now how to reconcile my idea of a catastrophic feedback mechanism, with the claim of finite temperature increase as claimed by IPCC, thanks to your and Roy’s comments.. Of course presupposing that the water vapour feedback is positive ( which it does not seem to be )

      Amnyway my long trained intuition as a physics researcher
      tells me that the earth has a thermostat in the form of water. And that may be the really interesting result of all the climate discussions. We did not know that before..

      • Anonymous says:

        Christopher Game replying to Carl.Weis’s post of September 21, 2010 at 11:45 PM.

        Dear Carl,

        You write: “intuition … that the earth has a thermostat in the form of water.”

        While this is a good start, I would like to suggest to you that a more modest physical intuition is that the earth’s energy transport process has evolved into a dissipative structure with a recognizable dynamical régime. It seems to me perhaps to be too bold to intuit that such a régime would be well described as a thermostat, at least if by that you mean a system that has a set-point of temperature. Such an evolved régime of dissipative structure, however, might quite likely have a recognizable relation, perhaps even a fixed ratio, between for example the insolation and the land-sea average surface temperature.

        It commonly happens in an open system that has more or less steady external conditions that eventually there evolves a dissipative structure. Very often, such a structure contains circulatory subprocesses. Early papers on such things are those of Helmholtz (translated 1868) ‘On Discontinuous Movements of Fluids’, Phil. Mag. series 4, vol. 36, no. 244, pages 337-346, of Rayleigh (1878), ‘On the Instability of Jets’, Proc. Lond. Math. Soc. 10: 4-12, followed by Sections 358-360 in volume 2 of Rayleigh’s Theory of Sound. A classic account of a structure with circulation is in Chapter 2 of Chandrasekhar (1961) <Hydrodynamic and Hydromagnetic Stability, Oxford University Press, Oxford. An approach by way of thermodynamics is in Glansdorff and Prigogine (1971) Thermodynamic Theory of Structure, Stability and Fluctuations, Wiley-Interscience, London, ISBN 0471302805.

        Such a circulatory subprocess in the atmosphere is the hydrological cycle, which can be viewed as an evaporative-circulatory heat pump. Perhaps the rate of operation of this heat pump is driven by the supply of heat.

        If a régime is well recognizable, that is to say, evolutionarily reproducible, one might hope to apply to it some kind of generalization of the second law of thermodynamics about extrema of dissipation functions.

        Catastrophic swings from one dissipatively structured régime to another are possible, and can even sometimes perhaps be described by catastrophe theory, see for example René Thom’s (1972/1976) Structural Stability and Morphogenesis. An Outline of a General Theory of Models, translated by D.H. Fowler, W.A. Benjamin Inc., Reading MA, ISBN 0805392785. One can picture a landscape of adjoining dynamical régimes, each the basin of attraction of its own fixed point about which there is overall negative feedback, and respectively separated from its neighbours by singularities about which there is overall positive feedback. Large perturbations can trigger a catastrophic shift of régime. This all depends on nonlinearity.

        If you believe in miracles, then perhaps you might believe that the IPCC “forcings and feedbacks” formalism can short-circuit this more orthodox path.

        Yours sincerely,

        Christopher Game

        • Anonymous says:

          Seems to me that we may not be dealing with so many attractors.. The world climate has been surprisingly stable over the last few million years. Or the barriers between attractors are very high…
          Evidently I agree: there is more than one attractor. If I suppose a thermostat effect of water, that can only function as long as the absorption of the other GHGs is small compared to that of water. So there certainly is other attractors. If they are fixed points or dynamical ( periodic/chaotic ), no idea.
          I would think that there are plenty of local attractors also dynamical ( El Nino, AMO etc. ) but they are sort of averaged when one looks at the whole globe.
          Anyway I know something about nonlinear physics but nothing about details of climate with oceans etc..

          • Anonymous says:

            Christopher Game responding to the Anonymous post of September 24, 2010 at 3:58 AM.

            “I would think that there are plenty of local attractors also dynamical ( El Nino, AMO etc. ) but they are sort of averaged when one looks at the whole globe.”

            I think that generally it is not a good move to let nature “sort of average” for one. One should usually explicitly estimate the small scale regularities whenever one can, and use the estimates in the investigation of the larger scale phenomena. It is mistake of the IPCC to ignore this principle.

            Christopher Game

    • Anonymous says:

      Christopher, you’ve definitely got “game”. Thanks for your contributions here, as you are bringing much more to the table of discussion than you’re taking. I’m just here to learn, and I appreciate it.

  46. Bob_FJ says:

    Dr. Roy,
    The K & T “Earth’s Energy Budget” diagram as used in the IPCC’s 2001 & 2007 reports gives the global average of energy leaving the surface via Evapotranspiration (E-T) as ~46% of the total. (Net)

    Some time ago, I commented over at Real Climate that if increased water vapour in the atmosphere was associated with increased E-T (evaporative cooling/latent heat), there should be a negative feedback such as is commonly discussed over increased cloud changes. Furthermore that a small change to the large proportion of 46% should result in a significant feedback change. However, they were not nice to me.
    Among other things, Gavin Schmidt replied that E-T would not be a feedback, but a forcing. Others, including Barton Paul Levenson aggressively asserted that; No, E-T, is only a small proportion of the total energy leaving the surface as radiation, (+390 W/m^2), whilst ignoring the back radiation, (-324 W/m^2), and that only 173 W/m^2 was absorbed by the surface anyway. The net HEAT loss from the surface via radiation was thus in the minority at 39.4%. (Per Trenberth’s numbers)

    Roy, could you please advise if I’m barking up the wrong tree?

    • Anonymous says:

      Christopher Game responding to Bob_FJ of September 21, 2010 at 5:47 PM.

      Dear Bob_FJ,

      May I make a short comment that does not address your main question to Dr Spencer?

      You write: “Among other things, Gavin Schmidt replied that E-T would not be a feedback, but a forcing.”

      May I point out this as an example of the muddled character of the IPCC “forcings and feedbacks” formalism?

      Yours sincerely,

      Christoher Game

  47. Bob_FJ says:

    Christopher Game, thanks your reply of September 22, 2010 at 12:26 PM , Concerning the potential feedback resulting from evapotranspiration. (E-T)

    The IPCC has estimated in 4AR that the forcing for anthro’ CO2 is about 1.7 W/m^2, and that the net for all anthropogenic forcings is about the same value.
    http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

    Adding to my earlier comment, according to Trenberth, 2007 levels of E-T resulted in a forcing of -78 W/m^2. Thus, without disputing his numbers, if (E-T) were to increase by say 1% in order to achieve some arbitrary increased water vapour level, there would be a feedback of -0.78 W/m^2, which is rather significant by comparison.
    Dare I add that Trenberth also gives “Thermals” as another -24 W/m^2, and that I think that there should also be an increase in thermals too.
    Add clouds, and how now to 2xCO2 sensitivity, I would think.

    If you need it, the Trenberth chart is here:
    http://www.flickr.com/photos/26175880@N05/3065365160/

    What do you think?

  48. Jedda says:

    Dr. Spencer,
    I am very interested in your responses about latent heat flux, and I’m not sure that I understood what you meant about convection with respect to:

    John Galt says: September 16, 2010 at 2:13 AM

    Could you please explain this in more detail?

    I also find this enquiry to be very interesting:
    Bob_FJ says: September 21, 2010 at 5:47 PM
    I look forward to you finding time to clarify these issues.

  49. Bob_FJ says:

    Christopher Game,
    Thanks your reply to mine above.
    I made an additional comment, but it is stuck in moderation, for three days now

  50. Bob_FJ says:

    Retrying my comment stuck in moderation:

    Christopher Game, thanks your reply of September 22, 2010 at 12:26 PM , Concerning the potential feedback resulting from evapotranspiration. (E-T)

    The IPCC has estimated in 4AR that the forcing for anthro’ CO2 is about 1.7 W/m^2, and that the net for all anthropogenic forcings is about the same value.
    http://en.wikipedia.org/wiki/File:Radiative-forcings.svg

    Adding to my earlier comment, according to Trenberth, 2007 levels of E-T resulted in a forcing of -78 W/m^2. Thus, without disputing his numbers, if (E-T) were to increase by say 1% in order to achieve some arbitrary increased water vapour level, there would be a feedback of -0.78 W/m^2, which is rather significant by comparison.
    Dare I add that Trenberth also gives “Thermals” as another -24 W/m^2, and that I think that there should also be an increase in thermals too.
    Add clouds, and how now to 2xCO2 sensitivity, I would think.

    If you need it, the Trenberth chart is here:
    http://www.flickr.com/photos/26175880@N05/3065365160/

    What do you think?

  51. Bob_FJ says:

    Retrying my comment with links removed, stuck in moderation:

    Christopher Game, thanks your reply of September 22, 2010 at 12:26 PM , Concerning the potential feedback resulting from evapotranspiration. (E-T)

    The IPCC has estimated in 4AR that the forcing for anthro’ CO2 is about 1.7 W/m^2, and that the net for all anthropogenic forcings is about the same value.
    [removed link]
    Adding to my earlier comment, according to Trenberth, 2007 levels of E-T resulted in a forcing of -78 W/m^2. Thus, without disputing his numbers, if (E-T) were to increase by say 1% in order to achieve some arbitrary increased water vapour level, there would be a feedback of -0.78 W/m^2, which is rather significant by comparison.
    Dare I add that Trenberth also gives “Thermals” as another -24 W/m^2, and that I think that there should also be an increase in thermals too.
    Add clouds, and how now to 2xCO2 sensitivity, I would think.

    If you need it, the Trenberth chart is here:
    [Removed link]
    What do you think?

    • Anonymous says:

      Christopher Game replying to Bob_FJ’s post of September 25, 2010 at 2:12 PM.

      Dear Bob_FJ,

      Thank you for your note of September 25, 2010 at 2:12 PM, referring to my note of September 22, 2010 at 12:26 PM.

      My note there was not intended to address the material questions of the energy transport processes that you asked in your post of September 21, 2010 at 5:47 PM; your material questions were directed to Dr Spencer, and I meant to leave them to him.

      My note there was intended only to refer to the formal structure of the IPCC formalism that was incidental to your questions. I was just pointing to the confusion that can arise from the “forcings and feedbacks” terminology, confusion that you reported in your post. I was criticizing the form, not examining the matter.

      I will still leave the material questions to Dr Spencer; he is man with the material knowledge.

      Yours sincerely,

      Christopher Game

  52. S Basinger says:

    Scienceofdoom.com has a pretty interesting series on clouds and water vapor. The following link is part 3 of the series.

    http://scienceofdoom.com/2010/09/18/clouds-and-water-vapor-part-three/

  53. Jim Eichstedt says:

    Roy,
    In response to your clarification to Carl on September 20 that overall or total feedback is negative, well, yeah, if it weren’t, we wouldn’t be here –earth would be fried or frozen. What gives me a headache is whenever climate scientists search for forcings (like AGW) to explain rises, dips or wiggles in temperature cycles, rainfall patterns, cloud cover extant, etc., when overshoot, ringing and oscillation, characteristics of negative feedback systems’ response to changing signals, are contributing to the wiggles. And these instabilities arise because of delays and hysteresis. Remember your feedback diagrams showing temperature changes relative to radiation fluxes? The displacement of stripes (slopes) is a consequence of earth’s memory, i.e. sea surface maximum temperatures lag air temp by a month, or changes in polar albedo follow longer term temp changes – lots of possibilities which, in aggregate, bend, split and spiral what we would like to be a single, linear slope.
    Can I give a simple example? I know that we don’t like using electronic amplifiers as an analogy for earth’s climate feedback, but how about a household thermostat as an example of negative feedback?
    We’ll build an insulated house in a frozen desert. It has a furnace that if left running constantly (no thermostat, just an “on” switch) would allow the house to achieve equilibrium with heat loss at140 degrees F. inside. The house is earth and the furnace is greenhouse warming. Let’s wire a thermostat. On earth, the thermostat comes from the presence of liquid water on our planet’s surface. We’ll set the thermostat at, say, 59 degrees. What happens?
    To see what happens, we’ll record temperatures continually. (Our house even has a meteorologist to record the temp’s!)
    If we look closely, we’ll see that the temperature never remains constant, that it is always increasing or decreasing in a sinuous wave. The furnace doesn’t kick in until the temp reaches 58 degrees (hysteresis) and because it takes awhile to heat the house, the furnace doesn’t shut off until 60 degrees. The temperature is constantly changing without any change to the system; in fact, it is a characteristic of the system! Now, what happens to the temp inside if it heats up outside, or if it cools down at night? Not much happens to the maximum and minimum inside but – here’s the cool part – the frequency and shape of the cycle changes. Do you see that the period between peaks decreases as delta temp increases? The temp before the furnace kicks in falls quicker because the house loses heat quicker; recovery when the furnace is running comes slower, though. So the curve isn’t a sine wave but saw-toothed. How about those temp patterns during glacial times when earth’s climate was way less stable than today? Our analogy’s patterns look like that.
    One last thing: the gain of some of the electronic audio amplifiers that I build as a hobby is for the most part set by the feedback (factor). Changing the gain or sensitivity of stages within the feedback loop has limited impact on the amplifier’s overall sensitivity because increasing gain also increases the effectiveness of the feedback. Kapish? Now, this is true of a system with high open loop gain; the earth’s is low. But still, it suggests that feedback will mitigate changes due to forcings – at least until it breaks into oscillation and we have another glacial period!

  54. Stephen Wilde says:

    I said this in an article published some time ago and I still think it is right and relevant to this thread:

    “It is the ability of the evaporation process to choose which medium (water or air) to extract the necessary energy from that ultimately stabilises the Earth’s equilibrium temperature, maintains the ‘normal’ energy flow from water to air and thus enables the Earth to retain it’s oceans.

    In every situation any extra energy from any source in the air alone fails to get transported into the ocean bulk. All energy removed from either the water or from the air by evaporation becomes latent energy in the air which does not raise the air temperature of the air (it being latent) so that the temperatures of the air and of the topmost molecules in the so called ocean skin always move towards equilibrium The flow of latent energy (held by water vapour) from surface to space is further enhanced via wind, convection and ultimately condensation out at a much higher level above the surface where that energy is more readily radiated to space.

    Thus extra energy in the air from extra GHGs increases the evaporation rate which increases the speed of the hydrological cycle which prevents the extra energy in the air from warming the oceans whether via the ocean skin theory or otherwise.

    AGW is thus falsified because the air cannot warm the oceans and the air circulation systems always adjust to bring surface air temperatures back towards sea surface temperatures.

    Climate models do not reflect this obvious truth and the ideas of Tyndall et al whilst correct if taking the air in isolation cannot affect the global equilibrium temperature set by the constantly varying interplay of sun air and oceans.”

    • Anonymous says:

      Christopher Game responding to Stephen Wilde’s post of September 27, 2010 at 7:37 AM.

      Dear Stephen Wilde,

      You write: “In every situation any extra energy from any source in the air alone fails to get transported into the ocean bulk. …

      Thus extra energy in the air from extra GHGs increases the evaporation rate which increases the speed of the hydrological cycle which prevents the extra energy in the air from warming the oceans whether via the ocean skin theory or otherwise.

      AGW is thus falsified because the air cannot warm the oceans and the air circulation systems always adjust to bring surface air temperatures back towards sea surface temperatures.

      Climate models do not reflect this obvious truth …”

      To check that I have got your message, I loosely and selectively paraphrase it. If my paraphrase is wrong, you will put me right.

      Christopher’s loose and selective paraphrase, subject to Stephen’s correction:
      Added CO2 causes initially retention of energy in the atmosphere. This retained energy must go somewhere. None of it can in the net result go into warming the oceans.

      Christopher’s comment on this paraphrase:
      It is true that added CO2 causes initially retention of energy in the atmosphere. It is true that this retained energy must go somewhere.

      But it is not true that none of it can in the net result go into warming the oceans.

      Let us consider a pulse of added energy, due to a pulse increase in CO2, in order to avoid some unnecessary problems of time integration. The time integral can be deduced from the pulse response.

      The retained energy pulse can in principle go three ways:
      (1) some of it can stay in the atmosphere;
      (2) some of it can be radiated to space;
      (3) some of it can go into the oceans.

      I think there is agreement that both (1) and (2) will happen. But we disagree about (3).

      The transfer of energy across the ocean/atmosphere interface can be by
      (a) radiation,
      (b) evaporation-condensation associated with convection,
      (c) conduction associated with convection.

      You are saying that the mechanisms (b) and (c) will necessarily outweigh mechanism (a) in the net transport for the case of a pulse of energy added to the atmosphere as a result of a pulse CO2 increase.

      Though you do not explicitly mention radiation in your post, I think we will agree that mechanism (a), radiation, will at least initially tend to increase the back-radiation, Ed. This will initially transport some finite amount of energy from atmosphere to ocean. You are saying that this transported energy will be outweighed by mechanisms (b) and (c). We may agree that secondarily, the increased ocean temperature will lead to an increase of radiation from the ocean absorbed by the atmosphere, Aa, and that this secondary effect will tend to compensate for the initial warming of the ocean, according to the Le Châtelier-Braun Principle.

      Let us consider mechanism (b), evaporation-condensation at the ocean/atmosphere interface, associated with convection. Initially the increase in atmospheric temperature will favour condensation, by the Le Châtelier-Braun Principle. This means that during the initial time when the atmospheric temperature briefly remains higher than the ocean surface temperature, an increment of evaporation-condensation will have a partial component contributory effect of slowing the cooling of the ocean. This will have an initial partial component contributory effect of warming the ocean. I think you are denying this. You are right to say that after the ocean temperature has been increased, there will result a secondary increase in cooling of the ocean by evaporation-condensation. But this will not happen until the ocean temperature has increased.

      You are saying more, something that is not dealt with in the just preceding paragraph. You are saying that the added heat that remains in the atmosphere will change the dynamics of the atmospheric energy transport process. Indeed I agree with you about that. I think it quite likely that the added heat, that stays in the atmosphere, will have the effect of speeding up the hydrological cycle by supplying it with more driving energy. The hydrological cycle can be viewed as an evaporative-circulatory heat pump. Speeding it up will cool the ocean. You are saying that this speeding up will necessarily fully compensate for the initial warming component effect that I described in the just preceding paragraph, indeed that it will fully compensate for the combination of all three initial ocean warming effects that I have described.

      The same kind of argument applies to mechanism (c), conduction associated with convection. The initial effect is to slow the conductive cooling of the ocean. I think you do not explicitly consider this mechanism in your post.

      Thus I argue that all three mechanisms will initially contribute some warming effect on the ocean, but that there will be an initial counter effect from the increase of rate of working of the evaporative-circulatory heat pump driven by heat retained in the atmosphere.

      I propose to you that it is not an obvious or necessary truth that the heat-pump effect will fully compensate for the other effects. You do not actually offer proof that it will do so. Your publications assert that there are all kinds of historical reasons why you think it will be so, but you do not give explicit quantitative proof. Your assertions cannot be accepted without explicit quantitative proof.

      Without prejudice, perhaps your assertions are true, that is to say, perhaps the speeding up of the evaporative-circulatory heat pump will fully compensate for the other effects, in such a way that the ocean temperature is held constant, and you can claim that you have pointed out a thermostatic process. But, without prejudice, perhaps they are not true. You have not offered a quantitative proof that the speeding up of the evaporative-circulatory heat pump will not actually eventually cool the oceans so that a pulse of CO2 would have a net cooling effect on the ocean.

      Thus you have not justified your assertion that it is an “obvious truth” that the air cannot warm the oceans. You will need to produce explicit quantitative proof to justify your assertion. An explicit quantitative proof will require some explicit quantitative physics. Handwaving will not do.

      Your current accounts are elaborate and complicated and as I read them, to check them quantitatively, you would need calculations at least as complicated as an AOGCM. Neither of us believes that an AOGCM could be relied upon to check your current accounts. To justify your assertion, you will need to do some more purely theoretical physics.

      Thus you have not succeeded in your admirable aim of falsifying AGW. Keep working on it.

      Yours sincerely,

      Christopher Game

  55. Mug Wump Wagathon says:

    All of the land based data is corrupted by the urban heat island effect. We do, however, have accurate satellite and radiosonde temperature change data for the top layer of the ocean and lower troposphere (see below). We know the truth.

    The sun was very active throughout the 20th century and this led to global warming. It’s happened before. Now the sun is anomalously quiet and it has been quiet for a while now. It is not surprising to many scientists that the combined satellite and radiosonde temperature data now indicate that there has been a cooling trend for years corresponding with this observed change in solar activity.

    The technology has been explained very well by Dick Thoenes (The stabilizing effect of the oceans on climate). “High quality subsurface ocean temperature, salinity and density data are now available from a fleet of 3000 submersible floats that are distributed throughout the world’s oceans.18 The floats are designed to sink to a depth of 1000 or 2000 m, drift at that depth for ten days, then return to the surface, acquiring data during the ascent. At the surface, the data are transmitted via satellite to a series of ground monitoring stations. The floats then repeat the descent/ascent cycle. The floats are not tethered and drift with the ocean currents. The principal features of the solar heating of the ocean at various latitudes through the year may be understood by examining the results from selected Argo floats. Figure 1 summarizes a year of data from 5 Argo floats covering a range of latitudes from the equator to the Antarctic Circle in the southern central Pacific Ocean. The temperatures at 5 depths, 5, 25, 50, 75 and 100 m are shown as a time series for the year. The latitude drift of the floats is also shown. Because of variability in the float actuators, the depths are averages for each float with a standard deviation of approximately 0.2 m. The average latitude, longitude, depths and temperatures for each float are given in Table 1. The average temperatures show the expected decrease in temperature at higher latitudes.”

    What we see is that Observational evidence in the real world simply does not support the data and the adjustments to the data and all of the variables and parameters that are used to capture ‘reality’ in the GCM world.

    “The observed ocean heat content trends were calculated by Josh K. Willis of NASA’s Jet Propulsion Laboratory and Craig Loehle of the National Council for Air and Stream Improvement, Inc. Loehle’s calculations have a smaller margin for error than Willis, because Willis only uses annual average data. The heat deficit shows that from 2003-2008 there was no positive radiative imbalance caused by anthropogenic forcing, despite increasing levels of CO2. Indeed, the radiative imbalance was negative, meaning the earth was losing slightly more energy than it absorbed.

    “Since the oceans are the primary reservoir of atmospheric heat, there is no need to account for lag time involved with heat transfer. By using ocean heat as a metric, we can quantify nearly all of the energy that drives the climate system at any given moment. So, if there is still heat ‘in the pipeline’, where is it? The deficit of heat after nearly 6 years of cooling is now enormous. Heat can be transferred, but it cannot hide.” (William DiPuccio)

    “Even when alarmist evidence is conclusively discredited (e.g. the hockey stick graph), the climate alarmists continue to use it, and to dismiss all conflicting evidence no matter how sound or voluminous it may be. When their own claims fail, they revise the evidence, not their hypothesis. Recent examples of this have involved the current global cooling trend, the absence of a signature tropical tropospheric hot spot, Antarctic cooling, oceanic cooling, unchanged rates of sea level rise, etc. All these phenomena have been subjected to dubious data manipulation trying to make a silk purse to suit GW out of a sow’s ear of empirical data which refuses to conform to their hopes.” (Walter Starck)

    Argos data is collected aboard the NOAA Polar-orbiting Operational Environmental Satellites (POES). “We must face the fact that the earth is now cooling,” as for example: Craig Loehle, “1,500-Year Climate Cycles, Broken Hockey Stocks, and Ocean Cooling,” Energy and Environment Vol. 20, 2009.

    Here’s the problem the Warmanazis have: they cannot tell the truth. A direct example is their refusal to admit that the oceans are in a cooling trend (and the unconscious incompetence of schoolteachers who continue to facilitate the ignorance and lies of these anti-humanist science authoritarians is mind-boggling).

    It’s a simple fact. The fact is based on easily knowable and understandable technology.

    To question the fact is to simply say humans are incapable of knowing anything. The Warmanists cannot say that, of course, as that would completely undermine the supposed certainty with which the Warmanazis pretend the Earth is doomed if they are not given power over the production and distribution of all goods and services used by Western civilization.

    So, that leaves very little room for them to continue beating a dead hoax. All they’ve got left is say something like, e.g., “Claims that the ocean has been cooling are correct. Claims that global warming has stopped are not.”

    Well, they’ve been caught saying just that. And, what they’re saying is more than misleading–more than a misconception–it demonstrates a total lack of understanding of physics, PERIOD.

    “If ocean cooling does occur, it DOES mean global warming as stopped during that time period.” (Dr. Roger Pielke, Sr)

    http://www.woodfortrees.org/graph/uah/from:1998/to:2009/plot/uah/from:1998/to:2009/trend

    Why are the oceans cooling?

    1410-1500 cold – Low Solar Activity (LSA) – i.e., Sporer minimum
    1510-1600 warm – High Solar Activity (HSA)
    1610-1700 cold – (LSA) – i.e., Maunder minimum
    1710-1800 warm – (HSA)
    1810-1900 cold – (LSA) i.e., Dalton minimum
    1910-2000 warm – (HSA)
    2010+ Global cooling predicted by some scientists, perhaps over the next 3 to 7 decades due to low solar activity, e.g.,

    Note: “The partial forecast indicates that climate may stabilize or cool until 2030-2040. Possible physical mechanisms are qualitatively discussed with an emphasis on the phenomenon of collective synchronization of coupled oscillators.” ~Nikola Scafetta

    And, Note: “… a long-term global cooling starting around 2002 is expected to continue for next five to seven decades…” ~Lu, Q.

    “Until we understand the oceans better we simply don’t know anything of the future of the climate. They may model the atmosphere as much as they want, without the oceans it is meaningless and if they include the oceans the models will be so complicated that they will be useless anyhow.” ~Sten Kaijser, 20 March 2010

  56. Mug Wump Wagathon says:

    ANSWER KEY (`The Catastrophists Quiz’):

    Question: Are the AGW witchdoctors’ predictions of catastrophe based on the casting of chicken bones or numerology and tarot cards?

    Answer: All of the above. It is the opinion, for example, of three of Japan’s leading scientists is that Climate science amounts to ‘ancient astrology’ and that climate change is the result of `natural cycles’ not `human industrial activity.’ Kanya Kusano wrote that the IPCC’s “conclusion that from now on atmospheric temperatures are likely to show a continuous, monotonic increase, should be perceived as an improvable hypothesis.” Shunichi Akasofu stated that, “We should be cautious, IPCC’s theory that atmospheric temperature has risen since 2000 in correspondence with CO2 is nothing but a hypothesis,” and cautioned that, “Before anyone noticed, this hypothesis has been substituted for truth… The opinion that great disaster will really happen must be broken.”

    Question: Shall prospects of global cooling be considered a disaster too?

    Answer: Note: Nikola Scafetta believes that, “The partial forecast indicates that climate may stabilize or cool until 2030-2040.” Scafetta’s forecast is based upon, `physical mechanisms’ and `the phenomenon of collective synchronization of coupled oscillators,’ such as for examples, ENSO effects and solar activity. Qing-Bin Lu believes that, “a long-term global cooling starting around 2002 is expected to continue for next five to seven decades.” Humanity will adapt and global cooling need not necessarily be considered a disaster for everyone. Even so there will be many challenges, as for example, Canadian wheat production. And, there always is the possibility of disaster. Walter Starck noted that if only humans really were able to heat the globe, “and it helps to prevent another ice age, this would be the most fortunate thing that has happened to our species since we barely escaped extinction from an especially cold period during the last ice age some 75,000 years ago.”

    Question: What if global warming were to continue for 100 years? But, what if as throughout the 10,000 years of the Holocene, the global warming had nothing to do with humans–still a disaster?

    Answer: Even if you assumed that humans were heating the globe by releasing CO2, as Walter Stark noted, humanity would run out of fossil fuels `well before any drastic effects on climate are possible.’ Nevertheless, we need to keep in mind that global warming has been much better for humanity than global cooling. To put global warming into historical perspective, the Minoan, Roman, and medieval warm periods have one thing in common. The current global temperatures are 5°F cooler than these previous warm periods. Even given the most alarmist predictions based on a `doubling of atmospheric CO2,’ as Walter Starck observed, `The net result…is most likely to be positive.”

  57. barry says:

    Dr Spencer, I’m curious to know if the ‘hot spot’ is an artefact specifically of GHG warming, or if it is a result of the warming of the atmosphere from any cause.

  58. barry says:

    Let me rephrase – is the putative ‘hot spot’ meant to be a result of warming from CO2, or a result of atmospheric warming regardless of the cause?

  59. Alexandre says:

    This contradicts most of the climate sensitivity studies.

    I think this idea deserves a paper to be submitted to peer-review.