NEW 4/10/09: There is an update to this post, see below the “read the rest of this entry” – Anthony
Guest Post by Richard Lindzen, PhD.
Alfred P. Sloan Professor of Meteorology, Department of Earth, Atmospheric and Planetary Science, MIT
This essay is from an email list that I subscribe to. Dr. Lindzen has sent this along as an addendum to his address made at ICCC 2009 in New York City. I present it here for consideration. – Anthony
Simplified Greenhouse Theory
The wavelength of visible light corresponds to the temperature of the sun’s surface (ca 6000oK). The wavelength of the heat radiation corresponds to the temperature of the earth’s atmosphere at the level from which the radiation is emitted (ca 255oK). When the earth is in equilibrium with the sun, the absorbed visible light is balanced by the emitted heat radiation.
The basic idea is that the atmosphere is roughly transparent to visible light, but, due to the presence of greenhouse substances like water vapor, clouds, and (to a much lesser extent) CO2 (which all absorb heat radiation, and hence inhibit the cooling emission), the earth is warmer than it would be in the absence of such gases.
The Perturbed Greenhouse
If one adds greenhouse gases to the atmosphere, one is adding to the ‘blanket’ that is inhibiting the emission of heat radiation (also commonly referred to as infrared radiation or long wave radiation). This causes the temperature of the earth to increase until equilibrium with the sun is reestablished.
For example, if one simply doubles the amount of CO2 in the atmosphere, the temperature increase is about 1°C.
If, however, water vapor and clouds respond to the increase in temperature in such a manner as to further enhance the ‘blanketing,’ then we have what is called a positive feedback, and the temperature needed to reestablish equilibrium will be increased. In the climate GCMs (General Circulation Models) referred to by the IPCC (the UN’s Intergovernmental Panel on Climate Change), this new temperature ranges from roughly 1.5°C to 5°C.
The equilibrium response to a doubling of CO2 (including the effects of feedbacks) is commonly referred to as the climate sensitivity.
Two Important Points
1. Equilibration takes time.
2. The feedbacks are responses to temperature – not to CO2 increases per se.
The time it takes depends primarily on the climate sensitivity, and the rapidity with which heat is transported down into the ocean. Both higher sensitivity and more rapid mixing lead to longer times. For the models referred to by the IPCC, this time is on the order of decades.
This all leads to a crucial observational test of feedbacks!
The Test: Preliminaries
Note that, in addition to any long term trends that may be present, temperature fluctuates on shorter time scales ranging from years to decades.
Such fluctuations are associated with the internal dynamics of the ocean- atmosphere system. Examples include the El Nino – Southern Oscillation, the Pacific Decadal Oscillation, etc.
These fluctuations must excite the feedback mechanisms that we have just described.
The Test
1. Run the models with the observed sea surface temperatures as boundary conditions.
2. Use the models to calculate the heat radiation emitted to space.
3. Use satellites to measure the heat radiation actually emitted by the earth.
When temperature fluctuations lead to warmer temperatures, emitted heat radiation should increase, but positive feedbacks should inhibit these emissions by virtue of the enhanced ‘blanketing.’ Given the model climate sensitivities, this ‘blanketing’ should typically reduce the emissions by a factor of about 2 or 3 from what one would see in the absence of feedbacks. If the satellite data confirms the calculated emissions, then this would constitute solid evidence that the model feedbacks are correct.
The Results of an Inadvertent Test
Above graph:
Comparison of the observed broadband LW and SW flux anomalies for the tropics with climate model simulations using observed SST records. The models are not given volcanic aerosols, so the should not expected to show the Mt. Pinatubo eruption effects in mid-1991 through mid-1993. The dashed line shows the mean of all five models, and the gray band shows the total rnage of model anomalies (maximum to minimum).
It is the topmost panel for long wave (LW) emission that we want.
Let us examine the top figure a bit more closely.
From 1985 until 1989 the models and observations are more or less the same – they have, in fact, been tuned to be so. However, with the warming after 1989, the observations characteristically exceed 7 times the model values. Recall that if the observations were only 2-3 times what the models produce, it would correspond to no feedback. What we see is much more than this – implying strong negative feedback. Note that the ups and downs of both the observations and the model (forced by observed sea surface temperature) follow the ups and downs of temperature (not shown).
Note that these results were sufficiently surprising that they were confirmed by at least 4 other groups:
Chen, J., B.E. Carlson, and A.D. Del Genio, 2002: Evidence for strengthening of the tropical general circulation in the 1990s. Science, 295, 838-841.
Cess, R.D. and P.M. Udelhofen, 2003: Climate change during 1985–1999: Cloud interactions determined from satellite measurements. Geophys. Res. Ltrs., 30, No. 1, 1019, doi:10.1029/2002GL016128.
Hatzidimitriou, D., I. Vardavas, K. G. Pavlakis, N. Hatzianastassiou, C. Matsoukas, and E. Drakakis (2004) On the decadal increase in the tropical mean outgoing longwave radiation for the period 1984–2000. Atmos. Chem. Phys., 4, 1419–1425.
Clement, A.C. and B. Soden (2005) The sensitivity of the tropical-mean radiation budget. J. Clim., 18, 3189-3203.
The preceding authors did not dwell on the profound implications of these results – they had not intended a test of model feedbacks! Rather, they mostly emphasized that the differences had to arise from cloud behavior (a well acknowledged weakness of current models). However, as noted by Chou and Lindzen (2005, Comments on “Examination of the Decadal Tropical Mean ERBS Nonscanner Radiation Data for the Iris Hypothesis”, J. Climate, 18, 2123-2127), the results imply a strong negative feedback regardless of what one attributes this to.
The Bottom Line
The earth’s climate (in contrast to the climate in current climate GCMs) is dominated by a strong net negative feedback. Climate sensitivity is on the order of 0.3°C, and such warming as may arise from increasing greenhouse gases will be indistinguishable from the fluctuations in climate that occur naturally from processes internal to the climate system itself.
An aside on Feedbacks
Here is an easily appreciated example of positive and negative feedback. In your car, the gas and brake pedals act as negative feedbacks to reduce speed when you are going too fast and increase it when you are going too slow. If someone were to reverse the position of the pedals without informing you, then they would act as positive feedbacks: increasing your speed when you are going too fast, and slowing you down when you are going too slow.
Alarming climate predictions depend critically on the fact that models have large positive feedbacks. The crucial question is whether nature actually behaves this way? The answer, as we have just seen, is unambiguously no.
UPDATE: There are some suggestions (in comments) that the graph has issues of orbital decay affecting the nonscanner instrument’s field of view. I’ve sent a request off to Dr. Lindzen for clarification. – Anthony
UPDATE2: While I have not yet heard from Dr. Lindzen (it has only been 3 hours as of this writing) commenter “wmanny” found this below, apparently written by Lindzen to address the issue:
“Recently, Wong et al (Wong, Wielicki et al, 2006, Reexamination of the Observed Decadal Variability of the Earth Radiation Budget Using Altitude-Corrected ERBE/ERBS Nonscanner WFOV Data, J. Clim., 19, 4028-4040) have reassessed their data to reduce the magnitude of the anomaly, but the remaining anomaly still represents a substantial negative feedback, and there is reason to question the new adjustments.”
I found the text above to match “wmanny’s” comment in a presentation given by Lindzen to Colgate University on 7/11/2008 which you can see here as a PDF:
http://portaldata.colgate.edu/imagegallerywww/3503/ImageGallery/LindzenLectureBeyondModels.pdf
– Anthony
UPDATE3: I received this email today (4/10) from Dr. Lindzen. My sincere thanks for his response.
Dear Anthony,
The paper was sent out for comments, and the comments (even those from “realclimate”) are appreciated. In fact, the reduction of the difference in OLR between the 80’s and 90’s due to orbital decay seems to me to be largely correct. However, the reduction in Wong, Wielicki et al (2006) of the difference in the spikes of OLR between observations and models cannot be attributed to orbital decay, and seem to me to be questionable. Nevertheless, the differences that remain still imply negative feedbacks. We are proceeding to redo the analysis of satellite data in order to better understand what went into these analyses. The matter of net differences between the 80’s and 90’s is an interesting question. Given enough time, the radiative balance is reestablished and the anomalies can be wiped out. The time it takes for this to happen depends on climate sensitivity with adjustments occurring more rapidly when sensitivity is less. However, for the spikes, the time scales are short enough to preclude adjustment except for very low sensitivity.
That said, it has become standard in climate science that data in contradiction to alarmism is inevitably ‘corrected’ to bring it closer to alarming models. None of us would argue that this data is perfect, and the corrections are often plausible. What is implausible is that the ‘corrections’ should always bring the data closer to models.
Best wishes,
Dick
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I’d like very much to see Lindzen’s response to the criticisms of the data.
This should be covered as a top level article.
chris y (06:40:41) :
Phil and others on feedback-
GE introduced a filament light bulb about 10 years ago that contains a small glass envelope surrounding the filament. The glass envelope has a multilayer dielectric coating that passes visible light but reflects mid-IR light back onto the filament (the envelope is a cylinder with the straight filament positioned at the focus of the reflecting envelope’s surface). As a result of this positive feedback, the filament requires less electrical power to achieve the same filament temperature. The coated envelopes cost a few pennies each to make (that process was what GE spent buckets of money developing). The efficiency improvement is on the order of 30% if I remember correctly. It does not run away, even though it is positive feedback.
However, this analogy does not apply to greenhouse gases, since they do not reflect energy back to the surface. They absorb energy and quickly thermalize with the local atmosphere.
You’re right about the GE lights, it’s easier to do with them because the hot bulbs produce IR that is closer to the visible that is emitted, it is the same principle however. Your statement about the GH effect is wrong though, measured downwelling IR at the surface is ~300 W/m^2
Alas.
Lindzen is always interesting and I thought maybe he had a smoking gun here.
Unfortunately, this looks like deja vu all over again. These charts are not based on the current ERBS dataset, it appears, which now correctly adjusts for changes in satellite altitude.
Many of you will recall that disparities between UAH satellite temperature data and other datasets (observations and models) were largely reconciled after the UAH dataset (produced by Spencer and Christy) was updated to version 5.2.
“”” _Jim (19:23:28) :
George E. Smith (17:26:59) :
…
But [taking] the mean surface temperature as being +15 deg C (this is a nonsense concept and there is no way we can measure that presently), then that would be 288K, and a black body radiation for that temperature would have a spectral peak wavelength of about 10.1 microns (From Wien’s Displacement Law).
Doesn’t it strike you (or any of the other incurious lot here this evening) as odd that this is/is near the middle of the atmosphereic window (8 – 14 um for the readers out there) here on earth given the transmittance properties of CO2 and H2O in that range?
Could I not then liken Planck’s spectral curve leading to ’spillover from a bucket’ as more LWIR energy transmits through this window (DIRECTLY into space I might add, unblocked by CO2 or H2O) as temperatures approach and exceed about 216K ( 0 deg F)? *
Did I mention that total radiative energy under the curve (for purists) – seems to be proportional to: Temperature_to_the_4th_power )MEANING that energy under the curge and the surge in the curve REALLY FAST)? “””
Jim,
The fact you cited struck me maybe 50 years ago. But it is not practical for me to write a complete encyclopaedia of thermodynamics in answer to any specific question someone has. Even Prof Lindzen, had to curtail his essay, and therby leave openings for critcism, such as he has received here.
The presence of the atmospheric window from about 6-12 microns is a very key element of the temperature regulation exerted by water; and a thorn in the side of the CO2 haters.
The real cooling of the earth takes place in the hottest tropical deserts under the midday summer sun, with surface temperatures of +60 deg C or higher. This raises the surface irradiance by a factor of as much as 2x over the global mean energy loss rate, and per the Wien’s Displacement Law, it moves the thermal radiation peak (for those regions) down to the 8.8 micron range, which is well within the window. The thermal continuum radiation has to be bounded by the black body radiation for that temperature, and for BB radiation, only 25% of the total energy is emitted below the spectral peak. So most of the shorter wavelenghts of the desert thermal radiation are also within the window. On the long wavelength tail; the ozone “hole” takes out a chunk in the 9-10 micron range, and at those higher surface temperatures, the 15 micron CO2 band is moved even further down the long wave tail of the thermal radiation spectrum.
Guess what ! ? ; hot tropical deserts are quite known for being devoid of moisture, and the bottom end of the 9 micron atmopsheric window, is actually a water absorption band from 4-8 microns. So in the deserts of Africa and The Middle East, that atmospheric window is wide open all the way down to around 4.5 microns, where it actually runs into another CO2 band. the 9-10 micron ozone hole is the only missing part of the 4.5-13.5 window, in the absence of water vapor.
So just what is it, that is going to drive the earth through that atmospheric window till it runs into the 4 micron CO2 band. CO2 isn’t going to do it, even at 10 times the current level, and water vapor isn’t going to do it either because the only parts of the earth surface that get hot enough to move the thermal raidation spectrum into that window, don’t have any water vapor to speak off anyhow; and the contibution of the 15 micron CO2 band is greatly attenuated.
While to total Stefan Boltzmann radiated energy may go as T^4 for BB like energy losses; the Peak Spectral Radiance at the thermal radiation spectral peak varies as the 5th power of the temperature; not the 4th, so it really goes up fast with temperature; and at the same time Wien’s Displacement Law moves the spectrum further away from the CO2 15 micron band, and eventually even the 9-10 micron ozone band starts to lose its influence in the hottest places.
It is interesting to note that the ozone band is very much narrower than the 15 micron CO2 band. And that is because the CO2 absorption starts right at ground level for the first few meters; where the atmospheric pressure is highest, and hence the collision broadening is maximised, and also the atmospheric temperature is highest; so the Doppler (temperature) broadening is also highest.
Ozone on the other hand exists in a thin layer high in the atmosphere, where the atmospheric pressure is much lower and so is the atmospheric temperature; so both the collision and Doppler broadening of the ozone band are much lower.
So I’m afraid it just is not possible to make a Physics case for CO2 having major influence on the earth’s cooling processes.
Now at the colder polar regions; the tempertaure can move low enough to move the thermal radiation spectral peak right on top of the CO2 band; but then at those temperatures, the total emittance is at least an order of magnitude lower than for the tropical deserts; so there’s not much IR to be captured by CO2, and the peak spectral emittance at that temperature is down by even more than an order of magnitude; because of the Wien’s Displacement Law.
Thisa sort of simple physics analysis, demonstrates why the climate science concept of an isotropic earth at +15 deg C emitting 390 W/m^2 everywhere; and the very concept of a “mean global surface temperature” (or lower troposphere); is sheer rubbish; and why standard climatology “science” is in the same category as Astrology and Economics.
Now Meteorology has fairly sound observationa science behind it, which may be why most Meteorologists, appear (to me) to be IPCC skeptics.
The ones I know personally; who are paid good money by people who have a highly vested interest in knowing what the weather ahead is really going to be; are first of all excellent meteorologists, and secondly total MMGWCC skeptics.
George
chriscolose (17:20:58) :
“Almost every thread I see here is a blatant misrepresentation of the science (like your post on CFC’s and ozone) or other analysis problems, and somehow it remains one of the more read blogs on the web.”
A rather bold generalization wouldn’t you say? I suspect that the high level of readership reflects the “audience” appetite for balance. Even if your (false) claim were true – WUWT represent a healthy opposing point of view to the massive MSM campaign attempting to prop up AGW.
What most alarmists don’t seem to fathom is that real people want balance in their decision/learning process. Balance arrives on the wings of debate.
Anthony,
re: above censorship claim.
If the Colose (actually, John’s) account is inaccurate and the reprint omitted smears and ad homs (which I think is probable), can’t you just publish the original and be done with it?
I never like the idea of deleting posts because of situations like this. The best solution would seem to be dumping them into a “troll thread” so that readers could judge for themselves.
REPLY: Unfortunately, wordpress.com hosting has no “move comment” feature. I wish it did. Maybe that is a case for me to move to a dedicated server. – Anthony
BCC (11:45:22) :
These charts are not based on the current ERBS dataset, it appears, which now correctly adjusts for changes in satellite altitude.
Read the update above. Lindzen has apparently addressed this and noted that with the adjustments, the anomaly still represents a negative, albeit with a smaller magnitude, feedback. That he also questions the adjustments would be immaterial if it is still negative, not positive.
Mark
I have perused most of what is written above; but I can’t claim to have fully digested each post.
I have to say that reading about feedbacks and ice ages got a little wearying.
Whatever it is that causes ice ages; either going into one; or coming out of one, it certainly isn’t some minor event like an eruption that blocks a lot of sunlight for a few weeks, and kicks in an ice positive feedback to cover the whole place with ice. It seems pretty clear to me that significant shifts in the earth orbit, and/or solar output are required to cause such events; and to a large extent those things seem to be well understood by geologists and the like.
But to talk about ice ages in the context of whether water and clouds are positive or negative feedback; is somewhat grasp[ing at straws.
Water (H2O) in vapor form, liquid and/or solid form (clouds) can be construed to exhibit either positive or negative feedback (if that is what you want to do).
You can argue that more warming causes more evaporation, hence more water vapor; and more warming; and call that feedback if you like; or if you want to be realistic; you can simply say when the temperature (in some region) changes to a new value (higher or lower); and water is around (oceans lakes etc) the total amount of water vapor in the atmosphere (in that region) also changes to a new value.
You can find a set of steam tables in the CRC handbooks that relate temperatures and water vapor pressures. You don’t have to invoke feedback to come up with those tabulated values.
Likewise, if the TSI changes 0.01% for some period of time; and pours some more radiant energy onto planet earth; you can expect that the amount of water vapor in the atmopshere will change to a new value as well.
Arguably; some initial state might be considered to be a steady state, and after a change, say in TSI, a different steady state might be reached. The change is being caused by a change in some driving variable; such as TSI, and several effect variables such as atmospheric water vapor, and mean temperature may change to new values. It was the TSI change that caused the other two variables to change; and not some feedback effect between the two driven variables.
Now the problem with all of this is that the earth is never even remotely in an equilibrium state. Every day it rotates on its axis so the solar insolation reaching some portion of the globe over some particular terrain, will cause temperatures, and vapor pressures, and lots of other variable to change, and it won’t ever be in equilibroum.
Averaging some set of these variable may lead one to think there is an equilibrium; but the mistake is in doing the averaging.
The earth most certainly does not average anything that happens all over the globe. It does integrate the instantaneous values of everything that is changing to get from one set of conditions to another; but that is not an average result. The system is highly non-linear in any case; so what is the purpose of an average value.
But as far as water regulating temperatures over any region of the earth; the presence of water in a vapor form tends to cause heating in some locations, and cooling in others; such as when the water vapor absorbs solar near infra-red radiation and heats the atmosphere, but cools (relatively) the surface due to the insolation loss to the atmosphere. But in cloud form; the surface effect is always to cool the surface if there are more clouds. The clouds may be warmed by the energy they absorb; and simple convection forces will transport that heated atmosphere and water to higher altitudes, where eventually that excess energy is lost to space.
No other so-called GHG exists in all three phases in earth’s atmsopehre, as does water; so none of them do anything like water does in the atmosphere.
And whether you call it feedback; negative or positive; it is happening on a continuouis 24/7 basis right now; it isn’t waiting for some trigegr to start or end an ice age; so its effect is a part of our everyday weather and our current and future climate.
George
Mark A York
Check out this NASA link
http://earthobservatory.nasa.gov/Features/GlobalGarden/
Yes the planet is greening. Whether it’s the warming, the CO2 or both, it means that rainforest destruction is definitely balanced elsewhere. While this is fortuitous and accidental, it remains a fact. However there are plenty more environmental problems for you to worry about and every one of them is more urgent than global warming. And that’s the real danger of this issue – it takes all the funding, diverts attention and gives polluters a get out of jail free card: “It’s not us, it’s that global warming”.
Weren’t the corrections made due to decay in the satellite’s orbit? It does make sense that a satellite slightly closer to the ground would detect more radiation.
Phil- you say- “You’re right about the GE lights, it’s easier to do with them because the hot bulbs produce IR that is closer to the visible that is emitted, it is the same principle however.”
“Your statement about the GH effect is wrong though, measured downwelling IR at the surface is ~300 W/m^2”
Say what? I didn’t say anything about downwelling IR radiation at the surface, and bringing this up does nothing to refute what I said.
I said that your analogy using a reflective dichroic mirror is wrong. A layer of clear atmosphere sprinkled with CO2 will not reflect IR. It can absorb IR. It can re-radiate IR over a different blackbody curve having a peak wavelength that is characteristic of the temperature of the atmosphere at that location.
The dichroic absorber is a better analogy, and multiple spaced plates of dichroic absorbers would be an even better representation of the situation. That doesn’t mean there is no down-welling IR.
Anthony, about update 2:
The correction made by the satellite people can be found here:
http://asd-www.larc.nasa.gov/~tak/wong/f20m.pdf
While the SW reflection is about the same as before the correction, the LW emissions TOA (top of atmosphere) are a lot smaller, with as result that there is no net loss of energy anymore, but a net gain. See Figure 5 in the above link and compare that to the Wielicki 2002 figure in the header.
Thus there is no negative feedback at all. That is not a “positive feedback” either, as it seems that the change in radiation balance is a stepwise change, not a gradual change linked to GHG increase.
Further, as the insolation ánd the outgoing LW radiation get up, that points to a reduction in cloud cover, which is not covered by models: still the SW reflection is significant too high in the models and outgoing LW and net difference is (not-significant) too low.
What I was wondering all the time since the works of Wielicki and Chen in 2002, is if clouds are cause or effect of temperature. It looks like that clouds may be a cause (as Dr. Spencer also suggests), but what causes cloud cover to change?
Anyway, as several main players have switched recently (PDO, NAO, flattened ocean heat content, temperature,…) we may see interesting years to come…
REPLY: Thanks Ferdinand, it will indeed be interesting times ahead. – Anthony
Zach:
Yes, but it would detect more SW radiation as well as LW radiation. So one would expect the same corrections to be made to both. This is reportedly not the case.
“”” Ferdinand Engelbeen (14:16:39) :
Anthony, about update 2:
The correction made by the satellite people can be found here:
http://asd-www.larc.nasa.gov/~tak/wong/f20m.pdf
What I was wondering all the time since the works of Wielicki and Chen in 2002, is if clouds are cause or effect of temperature. It looks like that clouds may be a cause (as Dr. Spencer also suggests), but what causes cloud cover to change? “””
I guess I must be wearing my fingers to the bone for no reason. Nobody ever seems to bother reading it anyway.
Let’s see if there is any plausible reason for clouds to change.
See Wentz et al SCIENCE July 7 2007; “How Much More Rain will Global Warming Bring.” This is a satellite data paper; actual real world measured data; not some computer video game.
In the paper Wentz et al report (Wentz is with RSS in Santa Rosa, CA they seem to know something about climate data measurments.) that a one deg C (1 C) increase in mean global surface temperature results in a 7% increase in total global evaporation. They also report that total atmospheric water content increases by 7%, and so does total global precipitation; which is a no brainer since precipitation and evaporation must always balance (over time).
The GCMs (video games) on the other hand agree fully with the 7% increase in total atmopsheric water; but for the total evaporation and preciptation increase, they predict only 1-3% increase. Note the obligatory 3:1 fudge factor in the computer simulations.
You might think about that difference; according to the GCMs the total atmospheric water content increases from 2 1/3 to 7 times faster than the increase in precipitation; care to explain that; let’s say it is 4x with a square root of 3 either way factor to give the 1-7x range
So according to Wentz who actually measured it; increasing the mean surface temp by one deg C increased the water in the atmosphere by 7% and also the precipitation. It is widely reported in the literature that precipitation; whether rain snow sleet or hail, is often accompanied by the appearance of clouds in the sky; or an increase in the size or density or persistence time of the clouds already there.
It’s not unreasonable to suggest that their observed 7% increase in precipitation was accompanied by about the same 7% increase in area, density and/or persistence time of the clouds; and that would be a possible mechanism for cloud coverage changing.
Now these numbers from Wentz et al are rates. They did not actually observe a 1 deg C temperature increase during their data gathering period, which was a total of 19 years of observations. they said during the time involved the temp increased by 0.19 +/-0.04 deg C per decade.
So the feedback mechanisms are very clear. more surface temp rise (or fall) means more evap/total water, and precipitation and presumably more clouds. The more clouds leads to less ground level insolation due to increased albedo from the cloud increase, and increased absorption due to cloud density/area/lifetime, and that insolation reduction translates directly into surface cooling.
The erroneous notion that clouds are positive feedback comes from the idea that if the atmosphere warms up, clouds that exist will evaporate reducing the cloud cover. That may certainly be true over areas that lack water; but over the 73% of the surface that is water, any warming will result in the increase in Evaporation water and cloud formation leading to increased precipitation; which Wentz et al reported in 2007.
Some British video game players reported cloud evaporation resulting from a doubling of CO2 in their simulations; However they also reported that during their simulations their Playstation kept the surface temperature absolutely constant. Not only is that a violation of simple physical laws; but it totally short circuits the very mechanism by which CO2 doubling is supposed to increase the surface temperature.
I can’t be held responsible when supposed scientists do totally stupid things.
Bottom line is that cloud cover modulation via the mechanism documented by Wentz et al provides all the negative feedback regulation of the earth’s surface and lower troposphere temperature. Anything that enhances cloud formation such as cosmic rays due to changes in solar magnetism, will result in lower temperatures being necessary to establish the required amount of cloud cover; and anything that inhibits cloud formation will require the temperature to increase, to make more water and clouds in the atmosphere.
Now this is about the 12th time I have posted this information at WUWT; I don’t plan on posting it again.
What’s to be said about purpoted “Climate models” or GCMs as they seem to be called; when they don’t even approximate the proper treatment of water in the atmosphere; it is after all only the most plentiful and the most powerful in terms of its spectral range in radiation absorption.
So would people please stop pestering us with “climate models” or GCMs that do not fully account for the atmospheric water in all three of its phases in which it is present at all times as a permanent component of the earth’s atmosphere.
George
Was reading more about ice ages and there cause. As pointed out by John Edmondson (11:38:30) , most of us have the cause of ice ages backwards (and I did also) — http://www.livescience.com/environment/050330_earth_tilt.html
Supposedly we come out of an ice age when the tilt is greatest.
Also, there is still debate about the causes of ice ages despite some people’s insistence that the science is settled (that sounds familiar for some reason … it will come to me).
http://www.sentex.net/~tcc/iceage.html
http://www.lbl.gov/Science-Articles/Archive/ice-age-sediments.html
http://en.wikipedia.org/wiki/Ice_age
We still seem to understand very little. Tilt periodicity is 40,000 years yet ice ages seem to occur only every 100,000 years. The calculated forcing from tilt is far too small to ‘force’ an ice age. In fact from some reading, there is even still some debate about the existence of ice-ages (the ‘ice-ages are fact’ amongst geologists is apparantly a fairly recent phenomenon — who knew).
Anyways, precision still seems to be the leading contender I think and large positive feedback is required in order to ‘trigger’ an ice age. And yes, I believe trigger is the right word since the length of time between ice ages seems to be random and unpredictable … (which it would not be with an obvious strong forcing).
So:
– tilt which doesn’t always ‘trigger’
– strong positive feed when it is triggered
– runs to saturation 🙂
But we should be humble and realize we don’t have a working theory that predicts, well anything about ice-ages. We don’t know cause, the timing, not the reason for its structure, how long we are out of an ice age … and so on.
Houston we have a problem
Toward Optimal Closure of the Earth’s Top-of-Atmosphere Radiation Budget
Norman G. Loeb, Bruce A. Wielicki, David R. Doelling, Seiji Kato, and Takmeng Wong
NASA Langley Research Center, Hampton, Virginia
G. Louis Smith
National Institute of Aerospace, Hampton, Virginia
Dennis F. Keyes and Natividad Manalo-Smith
Science Systems and Applications, Inc., Hampton, Virginia
ABSTRACT
Despite recent improvements in satellite instrument calibration and the algorithms used to determine reflected solar (SW) and emitted thermal (LW) top-of-atmosphere (TOA) radiative fluxes, a sizeable imbalance persists in the average global net radiation at the TOA from satellite observations. This imbalance is problematic in applications that use earth radiation budget (ERB) data for climate model evaluation, estimate the earth’s annual global mean energy budget, and in studies that infer meridional heat transports. This study provides a detailed error analysis of TOA fluxes based on the latest generation of Clouds and the Earth’s Radiant Energy System (CERES) gridded monthly mean data products [the monthly TOA/surface averages geostationary (SRBAVG-GEO)] and uses an objective constrainment algorithm to adjust SW and LW TOA fluxes within their range of uncertainty to remove the inconsistency between average global net TOA flux and heat storage in the earth–atmosphere system. The 5-yr global mean CERES net flux from the standard CERES product is 6.5 W m−2, much larger than the best estimate of 0.85 W m−2 based on observed ocean heat content data and model simulations. The major sources of uncertainty in the CERES estimate are from instrument calibration (4.2 W m−2) and the assumed value for total solar irradiance (1 W m−2). After adjustment, the global mean CERES SW TOA flux is 99.5 W m−2, corresponding to an albedo of 0.293, and the global mean LW TOA flux is 239.6 W m−2. These values differ markedly from previously published adjusted global means based on the ERB Experiment in which the global mean SW TOA flux is 107 W m−2 and the LW TOA flux is 234 W m−2.
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2008JCLI2637.1
“”” chris y (13:44:30) :
Phil- you say- “You’re right about the GE lights, it’s easier to do with them because the hot bulbs produce IR that is closer to the visible that is emitted, it is the same principle however.”
“Your statement about the GH effect is wrong though, measured downwelling IR at the surface is ~300 W/m^2″
Say what? I didn’t say anything about downwelling IR radiation at the surface, and bringing this up does nothing to refute what I said.
I said that your analogy using a reflective dichroic mirror is wrong. A layer of clear atmosphere sprinkled with CO2 will not reflect IR. It can absorb IR. It can re-radiate IR over a different blackbody curve having a peak wavelength that is characteristic of the temperature of the atmosphere at that location.
The dichroic absorber is a better analogy, and multiple spaced plates of dichroic absorbers would be an even better representation of the situation. That doesn’t mean there is no down-welling IR. “””
I don’t think any “dichroic mirror” model is tenable. Properly designed, dichroic mirrors are spectrum splitting, and what is not reflected is transmitted. In practice, small amounts of energy are absorbed (nothing but vaccuum is totally transparent).
And almost nothing but water droplets and ice crystals in our atmosphere is in any way refective in the sense of any significant amount of energy.
It is important to keep in mind that all GHGs including water vapor, are sufficiently low abundance in the atmosphere that they must act (optically) as individual molecules; essentially unaware of anything else like them. CO2 molecules for example are on average separated by about 13-14 layers of other molecules. So their optical activity with respect to any electromagnetic radiation is a property of a single molecule; and those kinds of reactions cover a variety of scattering mechanisms plus photon capture. Since photons are not supposed to be affected by electric fields, I would take a wild guess that some scattering can take place essentially as an optical refraction when the photon is within a certain range of a molecule; but I can’t give a good reason why. I would hope we don’t have to resort to quantum chromodynamics to explain how molecules scatter photons; but there are both elastic and inelastic scatter mechanisms.
About the only time molecules (gas) don’t act alone is when they are in collision. It has been hinted that while molecules are in collision, for a certain time and spatial distance, their electron orbitals interact in ways that permit otherwise forbidden transitions to occur.
Something like this is known in the solid state in the case of first generation yellow LEDs made from GaAs(1-x)P(x). GaAs is a direct gap semiconductor so the lowest conduction band minima is located at the same momentum as the valence band maximum, so a direct transition is allowed from the conduction band leading to a photon emission.
GaP on the other hand is an indirect bandgap semiconductor like silicon is, so the conduction band lowest energy level occurs at a different momentup than the valence band maximum; so a photon emission is quite unlikely, because a second particle (a phonon) must take part in the transaction to conserve the momentum (since photons have no momentum).
A breakthrough occurred with the discovery that a GAP and also indirect bandgap GaAsP alloys such as the yellow mixture, could be doped with significant amounts of Nitrogen, which replaced the P or AS atom in the lattice forming a so-called iso-electronic trap. In effect in that location you had a Gallium Nitride alloy, whith a somewhat larger bandgap; which readily trapped electrons from the conduction band. Because the nitrogen atom is locked in the crystal lattice, the location of the transition is confinced to the dimensions of the nitrogen atom; so the spatial location of the transition is very localised in space; and by Heisenberg’s uncertainty principle; the product of location uncertainty and momentum uncertainty is greater than h/2pi, h being Planck’s constant. So as a result of the tight tolerance on the spatial location of the event; the momentum is more uncertain, so the probablility of the electron jhaving a momentum uncertainty large enough to put it over the valence band maximum becomes large so the previously unfavorable transition now becomes quite likely so only a photon; in this case in the yellow spectral range is emitted. No phonon is requred and there isn’t an energy loss as a result.
This is the clearest experimental confirmation of the correctness of the Uncertainty principle in ordinary experience that I am aware of. Modern yellow LEDS are extremely efficient, but no longer empoly this Heisenberg effect; so they don’t use nitrogen doping, but are based on a quaternary alloy instead AlInGaP. Teh bandgap of these alloys can be varied over a wide range while keeping the bandgap direct, and simultaneously lattice matching the crystal to a Gallium Arsenide substrate so it can be grown strain free.
So this is a case where close proximity of atoms alters the material properties in such a way as to make a previously forbidden transition allowable.
Evidently the intermingling of electron orbitals during gas molecular collisions, is what allows previously disallowed transitions to occurt and premit gases to emit a broad band of continuum radiation governed by similar constraints to black body radiation (but not necessarily black) couold be grey red or blue etc.
My molecular Physics is sufficiently faded in history to not be able to explain this more rigorously; but I think you should get the general idea.
It is the thermal agitation collisions of gas molecules that provide the mechanism for continuum radiation; and those same collision statistics define the temperature; whcih is why such thermal radiation from gases is a function of temperature just as in solids or liquids.
So the atmospheric gases really don’t behave as mirrors; they can absorb photons over certain spectral ranges; but emit a borad emission range unless the gas density and temperatures are so low that spontaneous emission occurs before collisions occur. That depends on the lifetime of the excited state(s)
The energy involved in the molecular collisions is related to KT, and derivations of the spectrum of BB radiation are based on the assigning of energies like that to the distribution of molecules and the Maxwell-Boltzmann distribution of kinetic energies.
Specific heats can be calculated by somewhat similar strategies; the classical case being that of Sir James Jeans, who first derived the specific heats of solids at low temperatures.
I think I’m getting a bit out of the box here.
George
“Ian Schumacher (18:49:40) :
. . . if what you described occurred, there would be a gradual transition (a gradual reduction of positive feedback, and/or increase or negative feedback). This would show up as a decrease in the rate of change of temperature coming out of an ice-age. However, looking at the little and local data we have (and therefore ‘possibly’ not representative) this is not what happens.”
Yes – if the feedback multiplier drops when it’s energy source starts deplete itself, you would expect to see a relatively smooth curve at the boundaries of the transition between an ice age (large feedback amplifier) and an interglacial (small feedback amplifier or negative net feedback), and vice versa, instead of a square function. Having said that, my understanding is that the temporal resolution of ice core data is very poor – on the nature of about 500 years. Given what I know about Nyquist sampling frequencies, this means that the ice core data will not be able to reflect changes in temperature that occur at frequencies faster than apporoximately 1000 years, plus or minus a century or so. There could well have been a ramp-down of the feedback multiplier, it’s just that it can’t be detected at the sampling rate we’re stuck with.
Incidentally, I largely agree with what I think to be the point of George Smith above. Most of the people posting here have technical backgrounds of varying complexity and there is naturally a tendency to try to do what you can to mathematically or scientifically support your opinion based on the very imperfect infomation we have regarding the climate. The only way you can do this is by making a lot of assumptions, such as an equilibrium condition. But at the end of the day, you have to recognize that all you have is an argument – not proof.
My position on how feedback in the climate system should behave, for example, makes qualitative sense to me (maybe not to others), but I have to admit that I have not quantified any of the important variables. For example, if feedback sources in the climate do deplete themselves, as I think they must at some point, what is the size of each of the sources and what is the rate at which they deplete/recharge? What curve does the rate of depletion follow? I don’t know how someone would even begin to calculate these parameters, and if someone tried it would be hard to say that it is anything other than pure conjecture.
Even without this type of quantitative analysis, however, and even with the unproven assumptions we all make, I think it’s fair to say that there are VERY rational qualitative reasons for doubting that carbon dioxide plays as important a role in climate as we are supposed to simply accept as a matter of authority. I certainly beleive that no one has ever adequately supported the position that anthropogenic warming is settled, and in fact have a hard time believing that it ever will be settled.
maksimovich (17:42:28) :
“…After adjustment, …the global mean LW TOA flux is 239.6 W m−2. These values differ markedly from previously published adjusted global means based on the ERB Experiment in which the global mean … LW TOA flux is 234 W m−2.
so the newest adjustment goes in the other direction by massive 5.6 Wm-2, confirming Prof. Lindzen’s thesis (?)
As a professional flight control systems engineer and aerospace engineering professor, I know an awful lot about feedback loops and their stability, and more than a passing amount about the atmosphere. And to all the people who are trying to detract from Lindzen’s validated science, I’ve got news for you: He is exactly right on this issue. Any and every controls engineer can tell you that getting the phasing (sign) of the feedback correct is the difference between a control system that quickly diverges, out of control and into its destruction, and a well-behaved (well-damped) control system that corrects itself “as if by magic”.
And then there is the issue of Verification, Validation, and Accreditation (VV&A) of computer models. This is something that people in my business are absolutely forced to do, for all aerospace procurements by the government. To not perform VV&A would be outright stupid, and downright dangerous if you actually built and tried to fly an aerospace vehicle based on models that had not been VV&A’ed. IPCC should be ashamed. And as Hansen once called for “they should be put in jail.”
kurt (18:16:54) :
I don’t know if CO2 has to play any significant role. CO2 is not required in the ‘theory of strong positive feedback’. We have ice feedback, we have water vapor feedback. That might be enough.
I totally agree with you about everyone’s selective expertise. It very much colors how people look at things. It even causes some serious confusion over definitions and so on. We should try to show tolerance and patience. Assume that the other person is probably very good in their area, but realize that none of us knows everything and there is so much ‘noise’, measurement error, etc that a lot of different theories are viable — can be ‘justified’ by the data.
I think it is quite possible that sudden negative feedback kicks in (and positive feedback is reduced) … quite possible, I just wonder if it is likely, or if the much simpler possibility of saturation is more likely.
Positive feedback is reduced … we know that for sure. Ice near the poles is less important … so yes. Water vapor will be a pure greenhouse gas at first, but then it will be albedo changing clouds.
But there are 2 issues this theory needs to address:
1.) The smooth curve problem.
2.) The large delay problem (which should result in overshoot and oscillations)
Not impossible for sure, but also not addressed as far as I know.
George E. Smith (15:28:14) :
So according to Wentz who actually measured it; increasing the mean surface temp by one deg C increased the water in the atmosphere by 7% and also the precipitation. It is widely reported in the literature that precipitation; whether rain snow sleet or hail, is often accompanied by the appearance of clouds in the sky; or an increase in the size or density or persistence time of the clouds already there.
George, I didn’t even look at the models, as these are way out of reality for cloud cover. The increase of precipitation and thus clouds is real, at least for the Norhern countries: increased snowfall (in most years) in Scandinavia and a 6% increase in discharge of the main Eurasian river over the last 60 years.
But that doesn’t mean that the effect is the same everywhere. If you read the 2002 Wielicki and Chen papers:
http://www.atmos.ucla.edu/csrl/publications/pub_exchange/Wielicki_et_al_2002.pdf and
http://pubs.giss.nasa.gov/docs/2002/2002_Chen_etal_2.pdf
There is a sudden decrease in cloud cover in the 20N-20S band (in later papers extended to 30N-30S) between the earlier period (1985-1990) and the later period (1993-1999). This includes an increase of the Hadley cells turnover, drying out of the upper troposphere and less clouds, especially in the subtropics. That allows more sunlight to warm the oceans. This is visible in the heat increase of the oceans: mostly in the subtropics, while GHGs should have an effect more spread over the latitudes.
That is not directly compatible with the increase in GHGs, as the autors also conclude, but the result of some natural mechanism. Something similar happens (happened?) with the solar cycle and cloud cover: less clouds at high activity and more clouds at low activity. This enforces the effect of the small change in direct radiation…
The main remaining questions are what caused the shift and what is cause and effect…
“Is it just me? Am I that smart and everyone else that stupid. Isn’t it obvious that for life to exist on earth there must be a strong negative feedback effect in place. Without strong negative feedback does anyone sane really think that the climate on earth would remain stable enough long enough for life to evolve and prosper?”
On a geological timescale, there are wild swings of climate and mass extinctions of life.
Bill Illis:
You appear to have presented plots of sea level data from single locations while trying to suggest that these represent ocean-wide trends. I quick look around the site where you found the plots (http://www.aviso.oceanobs.com)reveals maps and plots of global data that clearly demonstrate that sea level is rising by about 3mm/year globally and is also rising in each of the ocean basins.
Due to the effects of prevailing winds and ocean currents there are places in each basin that do not show rises or in fact show falls. Presenting a single data plot from one of these spots in each ocean does not disprove the observed global rise of sea levels.
“Due to the effects of prevailing winds and ocean currents there are places in each basin that do not show rises or in fact show falls. Presenting a single data plot from one of these spots in each ocean does not disprove the observed global rise of sea levels.”
Cherry picking.