The prediction of how much manmade global warming we will see in the future (as well as how much past warming was manmade) depends upon something called “climate sensitivity”.
For many years, climate researchers have struggled to diagnose the Earth’s climate sensitivity from measurements of the real climate system. It’s almost a “holy grail” kind of search, because if we could discover the true value of the climate sensitivity, then we would basically know whether future global warming will be benign, catastrophic, or somewhere in between.
Here I present a new method of satellite data analysis which I believe reveals the climate sensitivity, and I also show why it has been so hard to diagnose from observations.
When the Earth warms, it emits more infrared radiation to outer space. This natural cooling mechanism is the same effect you feel at a distance from a hot stove. The hotter anything gets the more infrared energy it loses to its surroundings.
For the Earth, this natural cooling effect amounts to an average of 3.3 Watts per square meter for every 1 deg C that the Earth warms. There is no scientific disagreement on this value.
Climate sensitivity is how clouds and water vapor will change with warming to make that 3.3 Watts a bigger number (stronger natural cooling, called “negative feedback”), or smaller (weaker natural cooling, called “positive feedback”).
While there are other sources of change in the climate system, cloud and water vapor changes are likely to dominate climate sensitivity. The greater the sensitivity, the more the Earth will warm from increasing atmospheric greenhouse gas concentrations being produced by humans through the burning of fossil fuels.
There are three possibilities for climate sensitivity:
1. If clouds and water vapor don’t change as we add CO2 to the atmosphere, then the expected warming by 2100 would only be about 1 deg. C, which would not be a very big concern for most people. This is called the “zero-feedback” case.
2. If low clouds decrease, high (cirrus) clouds increase, or water vapor increases, then warming will be magnified. Most, if not all, climate models predict that clouds and water vapor will change like this, resulting in an amplification of the CO2-only warming of 1 deg C to as much as 4.5 deg. C or more. This is called the “positive-feedback” case, and the greater the positive feedback, the greater the warming. (NOTE: If the sum of all positive feedbacks more than cancel out the 3.3 Watt natural cooling, then the climate system is inherently unstable…this is why you sometimes hear of climate change “tipping points”.)
3. If the climate modelers are wrong — and low clouds increase, high clouds decrease or water vapor decreases with warming — then the effect will be to reduce the warming to less than 1 deg. C. For instance, if that 3.3 Watts of natural cooling mentioned earlier increased to as much as 8 Watts from cloud changes, the warming would be reduced to about 0.5 deg C by 2100. This is called the “negative feedback” case.
Read more from Roy Spencer here: http://www.weatherquestions.com/Climate-Sensitivity-Holy-Grail.htm
In this simplied version of a paper entitled ‘Chaotic Radiative Forcing, Feedback Stripes, and the Overestimation of Climate Sensitiviy’ submitted on June 25, 2008 to the Bulletin of the American Meteorological Society Dr Spencer goes on to conclude that:
1. Current satellite estimates of climate sensitivity have a spurious bias in the direction of high sensitivity.
2. This bias is probably due to small, natural fluctuations in cloud cover.
3. The true climate sensitivity only shows up during those shorter periods of time when non-radiative forcing (e.g. evaporation) is causing a relatively large source of temperature variability compared to that from cloud variability.
—————-
Read Global Warming for Dummies Part 1 here: http://www.jennifermarohasy.com/blog/archives/000959.html
And Global Warming for Dummies Part 2 here: http://www.jennifermarohasy.com/blog/archives/002844.html
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Roy needs to read this.
http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/
“The simple physics explanations for the greenhouse effect that you find on the internet are often quite wrong. These well-meaning errors can promote confusion about whether humanity is truly causing global warming by adding carbon dioxide to the atmosphere. Some people have been arguing that simple physics shows there is already so much CO2 in the air that its effect on infrared radiation is “saturated”— meaning that adding more gas can make scarcely any difference in how much radiation gets through the atmosphere, since all the radiation is already blocked. And besides, isn’t water vapor already blocking all the infrared rays that CO2 ever would?”
sjy; yep; I agree totally with that; bearing in mind that the logarithmic decline in CO2 sensitivity to IR absorbtion becomes asymptopic, so saturation is never 100%; but this miniscule shortfall from complete saturation is more than compensated for by -ve feedbacks as my comment here explains;
http://www.jennifermarohasy.com/blog/archives/003208.html#comments
My comment is the final one because luke has not come back. I am curious as to what Roy Spencer thinks about Miskolczi’s model; it seems to be the coat-hanger upon which the rebuttal of AGW can be hung.
SJT, Are you suggesting that a climate scientist (Roy Spencer) who publishes in peer-reviewed journals should base his understanding of physics on comment at a blog? That doesn’t sound like you at all. 😉
“If low clouds decrease, high (cirrus) clouds increase, or water vapor increases, then warming will be magnified.”
I might expect this to be conventional wisdom but not at all obvious. Just as Schwartz’s estimate of sensitivity following CO2 and temperature increase to date, assumed all the warming to be CO2 related and is an upperlimit only, so is the received view.
Beers-Lambert (poorly motivated from the respect of modern physics) amounts to another such upper limit, and not a rigorous one. As the atmosphere is not in thermal equilibrium, any non-virtual OLR absorption by CO2 is shared as kinetic energy and therefore absorption, as little as there is, is free to well exceed subsequent emission.
I believe the state change of water to gas and back of 70 calories on a water planet dominates energy transfers within the atmosphere, and the OLR not absorbed near the surface passes thru.
Jennifer, a talk show host here in California, out of the blue send me a link to your blog. The post was about an Aussie astronaut warning that the ice age approaches, but the context isn’t the point.
The point is you’ve gone global! You have planetary reach. Winning hearts and minds and all that. Wtg.
The amount of radiation emitted from the earth must equal the amount of radiation absorbed by the earth from the sun when global temperature (if you are an RP Sr. fan when global energy content) is constant. When the earth is warming it emits LESS radiation then it absorbs, the difference accounts for the increased temperature(energy content). If the earth cools it would emit MORE radiation producing a lower temperature (energy content).
Thus
“When the Earth warms, it emits more infrared radiation to outer space. This natural cooling mechanism is the same effect you feel at a distance from a hot stove. The hotter anything gets the more infrared energy it loses to its surroundings.” makes no sense.
“”When the Earth warms, it emits more infrared radiation to outer space. This natural cooling mechanism is the same effect you feel at a distance from a hot stove. The hotter anything gets the more infrared energy it loses to its surroundings.” makes no sense.”
Makes perfect sense Q = esT^4
q = heat loss rate, e = emissivity, s = stefan-boltzmann constant, T = temperature. It’s pretty well established theory.
At a glance I reckon we must be careful in describing what we mean. The earth is hardly like a hot stove or a hot rock. Since climate change is only about surface temperatures most of which is driven by the sun we can’t do the black body comparison so easily.
Firstly; we don’t have to consider core temperatures as we do with a normal black body. There is quite a thickness of cool rock insulation around the core and there is no observation window to the cooking chamber.
IMO a more appropriate model is a rotating balloon seen by torchlight in some large but empty darkroom. I guess it’s too hard to imagine our sphere covered with fruit, juice and ice cream.
Gavin.
Are you saying that a warming body does NOT increase it’s radiation as it gets hotter?
Just the notion of a “radiative balance” when talking interms of ‘electromagnetic fluences’ is bizarre. The fluences are vector quantities and stasis inconceivable.
jan; it doesn’t make sense if, like the good Professor, you don’t seem to accept the logarithmic decline and therein saturation; the argument is, since CO2’s rate of excitation by IR is much slower than the rate of deexcitation by collision, there will never be saturation; therefore, the more CO2 you put into the atmosphere the more capacity there is to ‘trap’ heat and produce a radiative disequilibrium. This, according to Spencer Weart and Humbert, works hand in hand with a never-ending opaque atmosphere with a Tyndall-like upper daming effect preventing the trapped IR from leaving.
Leaving aside Miskolczi for the moment, and ignoring the inappropriateness of applying the Bernoulli effect to upper atmosphere gases, there are a couple of issue I like to put to the professor, unless, of course, he has dashed back into the international arena that James mentioned;
1. the excited CO2 molecule emits a photon; does that photon remove energy from that area?
2. does the emitted photon have a different wavelength from the absorbed IR?
3. If it does have a different wavelength does that mitigate its capacity to interact with higher levels of CO2?
4. in respect of both the down and up emitted photon, why doesn’t subsequent scattering enable the photon to escape from the atmosphere in a non-opaque window, or does the Professor assume that the CO2 blanket is uniform?
5. What does the Professor make of the plethora of -ve feedbacks to both thermal and radiative imbalances; such as declining relative humidity, increasing reactive halogens, and regional decreases in CO2, particularly in the Southern Oceans due to cyanobacterial activity?
Jan – “Makes perfect sense Q = esT^4”
OK then Jan you explain how a body such as the Earth CAN cool or warm. We know that it has done this in the past. If the Earth is a perfect black body as you say then the surface temperature must be the ideal black body temperature and never vary from this. Any increases or decrease in the solar insolation would be be immediately radiated or absorbed away.
So how does the Earth ocean/atmosphere work and why is it approx 33deg above the predicted black body temperature?
Gary – “The fluences are vector quantities and stasis inconceivable.”
Is the surface temperature of the Earth more or less constant over long time periods?
ender; let me guess where you are going with this; greenhouse, right; that being the case why don’t you tell us why this is wrong;
http://junkscience.com/Greenhouse/Kondis-Greenhouse.html
And since Prof. rabbet has disappeared like a speeding bullet, why don’t you enlighten us as to the mechanism by which CO2 traps IR and distributes heat.
As to periodic cooling of the earth, haven’t you heard of Milankovitch?
cohenite – “As to periodic cooling of the earth, haven’t you heard of Milankovitch?”
No I am asking you how does it cool or warm? I have heard of Milankovitch however in your model orbital changes would change the solar insolation. However as you have the Earth as a perfect black body it would therefore radiate less or more energy and stay the same temperature.
So how does the Earth warm and cool?
Jan: “Are you saying that a warming body does NOT increase it’s radiation as it gets hotter?”
Hey! I’m too old for questions like that.
After working round a few furnaces both hot and cold you’d reckon I should know the answer however I’m inclined to say the rate of heat loss from furnace internal combustion depends greatly on the outside wall thickness and insulation materials.
A better question would be, what can ignite by radiated hear from the fire bricks if the flame goes out? And would the same happen in a hot motor?
Folks: At crust temperatures I can say radiated heat in versus radiated heat out is extremely difficult to measure with your “body” as the only gauge.
I never said the earth was a perfect black body; don’t verbal me ender; greenhouse is a dumb concept; it doesn’t take into account regionalism, oceans and atmospheric layers which are vastly different from each other; all these factors intercede with not only re-radiation, but mitigation of incoming radiation as well; given this, Milankovitch will do the trick; now answer the question, or are you going to hide behind global average temp and excitable and feminised CO2 molecules?
cohenite – “I never said the earth was a perfect black body; don’t verbal me ender;”
No you didn’t however your answer to Eli invoking Stefan Boltzman equation for black body radiation seemed to imply it.
Now you are waffling again. I asked a simple question – how does the Earth cool and warm?
ender; read what I wrote; Milankovitch; and note that when the earth’s orbit is at its most elliptical the amount of solar radiation at perhelion is almost 25% greater than at aphelion; a 25% increase, or decrease in insolation would cool or heat, don’t you think, given the irregularities to the ‘perfect black body’ which I have described?
“And since Prof. rabbet has disappeared like a speeding bullet, why don’t you enlighten us as to the mechanism by which CO2 traps IR and distributes heat.”
Why don’t you ask Jennifer, she says CO2 is a greenhouse gas.
The Earth is round. Prof. Rabett went to bed.
It’s an energy balance. More in than out and the object warms up. Since the only way in and out is via radiation, for the earth to warm you can either increase the rate at which the energy comes in, or decrease the rate at which it goes out.
We know that over the past 30 years the rate of energy coming in (the total solar insolation) has not changed. More precisely we know that it has only changed a teensy amount, not enough to account for the observed changes at the surface.
There have been significant changes in the radiative properties of the atmosphere. These have decreased the rate at which the Earth radiates IR to space. To reestablish the equilibrium between incoming and outgoing radiation the surface warms.
Orbital changes: Eli takes it this is the next hot thing, take very long times compared to the observed changes. Eli would also remind the enthusiastic that orbital changes in insolation would be measured by the satellites which detect the TSI at the Earth
Greenhouse gas warming: Here is a simple explanation.
cohenite – “given the irregularities to the ‘perfect black body’ which I have described?”
So you have quantified the changes that happen however not the mechanism that warms or cools the Earth.
I guess we can try multiple choice as the fill in idea I had last time did not go too well.
Q – given that the solar radiation has dropped 25% then the Earth in response will:
A – Be radiating more energy than it is receiving
B – Be radiating less energy than it is receiving
C – Experience no change in radiation
Please indicate your answer A, B or C
Slightly off topic, but who over the last few days, has not heard the oft repeated dire warnings that the Arctic could be largely free of ice this (northern) summer. And al the fault of us evil western capitilist industrialists.
This side of Alice’s Looking Glass, in the real world, this does not appear to be happening.
In fact the Arctic sea-ice is bearing up very well as we approach mid-summer. http://www.noaa.gov/latest/noaa2.jpg
Meanwhile the Greenland ice sheet continues to pack on more and more of the white stuff.
I should have qualified this so I cannot be misinterpreted.
Q – given a theoretical example where the solar radiation has dropped 25% then the Earth in response will initially:
A – Be radiating more energy than it is receiving
B – Be radiating less energy than it is receiving
C – Experience no change in radiation
Please indicate your answer A, B or C
“ender; read what I wrote; Milankovitch; and note that when the earth’s orbit is at its most elliptical the amount of solar radiation at perhelion is almost 25% greater than at aphelion; a 25% increase, or decrease in insolation would cool or heat, don’t you think, given the irregularities to the ‘perfect black body’ which I have described?”
how could that affect anything? The heat radiates out as fast as it arrives, doesn’t it?
Cohenite writes
Leaving aside Miskolczi for the moment,
Why?
and ignoring the inappropriateness of applying the Bernoulli effect to upper atmosphere gases,
Normal fluid dynamics only breaks down at ~100 km altitude, well above the level at which the greenhouse mechanisms are operating (up to 10 or so km). For this to happen the mechanism of flow has to be molecular in nature (isolated collisions) rather than behaving as a continuous fluid. At best your statement about the good Bernoulli is a red hering, at worst the usual attempt to propagate ignorance
there are a couple of issue I like to put to the professor, unless, of course, he has dashed back into the international arena that James mentioned;
The Earth is round.
1. the excited CO2 molecule emits a photon; does that photon remove energy from that area?
Poorly formulated. A CO2 molecule excited by absorption of an IR photon almost completely loses its energy by collisions with surrounding molecules. That energy goes into heating the local surroundings. Other CO2 molecules can be excited into vibrationally excited states by collisions and radiate (~6% at 300 K). The radiated energy is removed.
2. does the emitted photon have a different wavelength from the absorbed IR?
Again, poorly formulated. CO2 molecules that are thermally excited and then emit will be excited to an entire range of vibrationally excited states. The average amount of population in each of these states is determined by the Boltzmann distribution, and each state can emit at a few different wavelengths as determined by quantum mechanics.
If you are talking about a molecule that is directly excited by radiation, that too is complicated. The mean time btw collisions is ~ a few hundred picoseconds. It takes ~100 – 1000 collisions for the molecule to vibrationally de-excite, on each collision the rotational state of the molecule changes and each rotational state emits at a couple of different wavelength
3. If it does have a different wavelength does that mitigate its capacity to interact with higher levels of CO2?
Yes if you mean higher up, or where the total pressure is lower, That is part of the greenhouse mechanism All CO2 molecules can absorb on the same vibronic transitions. OTOH, where it is colder, population in high lying rotational levels of the ground state will be lower and the probability of absorption lower because there are fewer CO2 molecules in that state which can absorb that wavelength. Each line is also broadened by collisions, so some emission from the wings of lines in lower regions will not be absorbed. See here for more details. Some of the emission from denser regions will thus be able to travel quite far.
4. in respect of both the down and up emitted photon, why doesn’t subsequent scattering enable the photon to escape from the atmosphere in a non-opaque window, or does the Professor assume that the CO2 blanket is uniform?
It is quite well known and repeatedly measured that the atmosphere is well mixed (the concentration of each of the gases is the same) up to again, about 100 km, well above where the greenhouse mechanism operates. The other part of your question is not clear. There will be redistribution of radiation (wavelength changes) due to clouds and overlapping absorption by other gases but they are also well mixed with the exception of water vapor for obvious reasons.
5. What does the Professor make of the plethora of -ve feedbacks to both thermal and radiative imbalances; such as declining relative humidity, increasing reactive halogens, and regional decreases in CO2, particularly in the Southern Oceans due to cyanobacterial activity?
Read the IPCC report, and while you are at it explain the universe and give two examples. This is well beyond what one can get into in a blog comment.
Wow – Eli on the blog. Holey cow ! This must a truly excellent den of pure sceptic evil if Eli is here, doing a bit of denialist slaying.
My appreciation. 🙂
Cohenite – old space rock – old son – can you explain this to a poor biologist
http://landshape.org/enm/radiative-equilibrium-miskolczi-part-4/#comment-126756
Yes, Eli forgot about turbulent mixing in the lower atmosphere which is somewhat unforgivable given that he mentioned that the atmosphere is well mixed, otoh on the scales of GCMs this can be neglected (and if you think it cannot, don’t get on an airplane)
I have a sense of complete unreality about current commentary on global warming. Fiddling while Rome burns, or rearranging deck chairs on the Titanic are metaphors [?] that come to mind.
Global temperature at the moment is 0.78 degrees F BELOW what it was this time last year. Last year was apparently the most rapid annual drop since proper measurement began [presumably satellites, 1979].
The sun is desperately quiet, with no sign of a real start to Cycle 24, despite numerous predictions that Cycle 24 sunspot should be littering the landscape by now.
We could be witnessing the start of an historical disaster, with practically no-one watching.
Penny Wong et al may be about to receive an object lesson in geophysics. After hubris, nemesis.
Eli, the problem is one of exhaustion—anonymous researchers rant with affiliations hidden…axes wave well ground by hands obscured and thus secured from reasonable inquiries. The resident trolls, cheer.
Your past due date has expired, dude. The question is no longer whether the Earth is round. (It is.) Or your digression on the unknown climate sensitive to CO2. That has yet to be determined by anyone, much less by your honourific anonymity.
There’s no better response to your nonsensical rant than a few quotes from that master of the theatre of the absurd, Samuel Beckett and his play “Waiting for Godot.”
Eli, this is your line:
“Let us not waste our time in idle discourse! (Pause. Vehemently.) Let us do something while we have the chance! It is not every day that we are needed. Not indeed that we personally are needed. Others would meet the case equally well, if not better. To all mankind they were addressed, those cries for help still ringing in our ears! But at this place, at this moment of time, all mankind is us, whether we like it or not. Let us make the most of it, before it is too late! Let us represent worthily for once the foul brood to which a cruel fate consigned us!” This is your conceit.
To which I reply: “We are all born mad. Some remain so.”
The time has come to realise, Eli, for the moment, it is no longer about the science, you yourself claim as much by mere example, but the fraud, the psychological intrigue and the sociological pathology.
And it is versed in babble. Listen to yourself, then listen to Professor Lucky’s speech. Sound familiar? Perhaps you two attended uni together?
Ender: “If the Earth is a perfect black body as you say then the surface temperature must be the ideal black body temperature and never vary from this.”
The formula “Q = esT^4” is not for a black body I do not say it’s a black body in fact I do not particularly refer to earth but any body grey coloured or black.
Ender; “So how does the Earth ocean/atmosphere work and why is it approx 33deg above the predicted black body temperature”
The earths predicted black body temperature is around 279K not 255K which is a prediction for grey/coloured body in black body out.
You’re right prof., Miskolczi is the basis of this debate for the simple reason his model is correlating better with reality than the AGW models.
I disagree with your comment that the GHG’s are well mixed (although I note you put a caveat on H2O, the dominant GHG, which really should end this aspect of the discussion); rain scrubs CO2, reactive halogens, where present, destroy ozone. How else can you explain the great diurnal differences in temp in a desert but not in the tropics; either the relative scarcity of H2O in the desert explains things, or there is proportionately less CO2 in the desert than there is in the tropics. With urban areas, is the UHI affect a product of extra GHG’s, or convectional and conductive transfer of the heat generated mechanically by the city? These phenomenon do not tally with a well mixed atmosphere.
The most interesting question for me, which is being discussed at Niche and elsewhere, is that a thermal equilibruim can be achieved in the presence, globally, of a radiative disequlibrium. The issue is one of lags and, as AGW desperately supposes, sinks, which will catastrophically release the heat at a later date. Shwartz has increased his time constant from 5+- 1 yr to 8.5 +- 2.5 yrs; but Miskolczi is saying any lag, as a reflection of greenhouse forcing, is much shorter, and this is what we are seeing; temps declining, no extra heat in the ocean or atmosphere, while CO2 is increasing and, according to AGW, radiative disequlibrium due to ‘trapping’ of IR and its emitted derivatives; the interest is, what is achieving this Kirchoff ‘balance’; some mechanisms are becoming apparent, as is the ineffectual nature of CO2.
Gavin: “After working round a few furnaces both hot and cold you’d reckon I should know the answer”
You mean you can’t remember that the surrounding area was warmer when the furnace was running than when it wasn’t?
Rabbett; “More precisely we know that it has only changed a teensy amount, not enough to account for the observed changes at the surface.”
Precisely how do we know that?
“There have been significant changes in the radiative properties of the atmosphere”
Precisely how do we know that these changes and temperature changes have not had a common cause? The appears to be a slight loss of correlation with at least one of these supposed radiative properties and temperature of late.
“Greenhouse gas warming: Here is a simple explanation.”
Simple it is, but is it correct? One would think that since it is the so called greenhouse gases that radiate more of the heat (see the satellite images of the spectrum when there is a temperature inversion there are emission lines) that the more there is of these gases the more efficiently the atmosphere will lose the heat it has accumulated. It will also accumulated the heat faster so should more efficiently cool the planet.
Wes – what a pathetic drivelly response to a science comment. A ream of irrelevant twaddle. Give it away and open a bookshop for dead poets.
Gee Cohenite – dat’s a hard ‘un. mmmmm desert eh? – surface albedo and clouds.
SJT: I read the Realclimate link you gave.
It includes this:
“In reality, that mere percent increase, when combined properly with the “thinning and cooling” argument, adds 4 Watts per square meter to the planets radiation balance for doubled CO2. That’s only about a percent of the solar energy absorbed by the Earth, but it’s a highly important percent to us! After all, a mere one percent change in the 280 Kelvin surface temperature of the Earth is 2.8 Kelvin (which is also 2.8 Celsius). And that’s without even taking into account the radiative forcing from all those amplifying feedbacks, like those due to water vapor and ice-albedo.”
This looks like a deliberate attempt to claim that a one percent change in incoming energy will translate into a one percent change in absolute temperature.
Of course they don’t actually *say* that directly but a casual reader unfamiliar with the fact that the dependence is T^4 would assume that. But then 2.8 degrees is much more impressive than 0.7 deg isn’t it?
This seems to be a common technique on that site.
Gavin Schmidt claimed that the measured mid tropical troposphere warming was not at odds with the model outputs as they encompassed the measured results. What he didn’t say was that the *lapse rate* changes predicted by the models was of opposite sign to that measured.
Somewhat less than “the truth, the whole truth and nothing but the truth”.
He also claimed that the results were the same no matter whether the forcings were solar or CO2. Really? So incoming solar shortwave has the same effect as longwave. Hard to believe given the different penetration of seawater for one.
I doubt that Gavin and his mates are that good at spin. My guess is that Environmental Media Services must be having these articles edited and rewritten by a staff of professional, trained propagandists.
I did see Ender get a little pat on the head in the comments. How cute!
Jan: My furnace comments were in relation to this statement “When the Earth warms, it emits more infrared radiation to outer space. This natural cooling mechanism is the same effect you feel at a distance from a hot stove. The hotter anything gets the more infrared energy it loses to its surroundings”
Following my initial thoughts “I reckon we must be careful in describing what we mean. The earth is hardly like a hot stove or a hot rock. Since climate change is only about surface temperatures most of which is driven by the sun we can’t do the black body comparison so easily” after wondering what we really feel as a nearby cooler body. Sure a hot plate radiates and so does the oven however the hot plate is a conductor and the oven may be designed for convection heating with a cooling air stream surrounding it. What we “feel” close to a hot stove is a least debatable.
I spent a long time working with various heat transfer mechanisms and can flash between them and recall air could be heated most effectively by steel tubes when combustion was not present. It’s easy to recall extremes by way of illustration too. Some days I could walk from a furnace room into a deep freeze warehouse. What form of heat transfer kept the food solid? Hey equilibrium is something that we can “feel” happening but what controls the chill factor?
Now Jan, let’s examine for a mo what the satellites see in terms of temperature inversions and other layers in the atmosphere. From association what is the significance of UHI in the overall temperature measurement? What does this spectrum show us about other sources and sinks? Can we “see” heat transfer via water vapor at say the ocean surface? What about land such as desert? Calculating it is one thing, measuring it is another.
Eventually someone has to do the hard yards at every level.
“My guess is that Environmental Media Services must be having these articles edited and rewritten by a staff of professional, trained propagandists.” My guess if you’re an idiot.
Gavin: “Following my initial thoughts “I reckon we must be careful in describing what we mean. The earth is hardly like a hot stove or a hot rock. ”
From the TOA where the actual radiation to space comes from that is precisely what it is.
luke; what clouds? We’re in a desert. Actually the desert is a perfect example of the lack of uniform distribution of GHG’s; diurnally the only variable is incoming solar radiation which continually heats during the day despite the surface albedo; at night the absence of both solar and H2O means the temp drops; where does that longwave go if not out of the atmosphere?
cohenite: where does that longwave go if not out of the atmosphere?
It hides under his bed, beside the crocodiles.
Well yes exactly – desert – in general – no clouds, higher albedo !
What else would you expect. vis a vis other parts of the tropics – clouds and lower albedo.
And there is a thing called “circulation” which strangely moved air masses around the Earth (but why be too nitpicky)
Question for you is why then the desert night temperature doesn’t drop to -18C (or for black body physics picky types – thereabouts)- eh?
Why doesn’t the radiation just go zot out to the universe !
Luke: “Question for you is why then the desert night temperature doesn’t drop to -18C (or for black body physics picky types – thereabouts)- eh?”
because the theoretical black body equilibrium temperature is NOT -18C but ~6C. Try to get this straight. BB temp of moon is given as 1C which is a more reasonable figure and a fairer indication of what we can expect from relatively GHG free deserts.
reference pls
reference
http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html
equiv BB temp = (Q/s)^.25 = (342/5.67E-8)^.25 ~ 279K simple arithmetic. It is the same figure for the moon.
I thought there were reds under the beds. Red crocodiles?
“Red crocodiles?”
Only on the inside they are green on the outside.
Actually there is a quite good primer here:
http://www.sciencebits.com/OnClimateSensitivity
It is Nir J. Shaviv’s site so it is not from the evil AGW empire.
Funnily enough he gets climate sensitivity in the IPCC range.
“It was found that if the cosmic ray flux climate link is ignored and one averages the different empirical estimates for the sensitivity, one obtains that λ=0.54±0.12°K/(W m-2). This corresponds to CO2 doubling temperature of ΔTx2=2.0±0.5°K.
If the cosmic ray flux climate link is included in the radiation budget, averaging the different estimates for the sensitivity give a somewhat lower result, namely, that λ=0.35±0.09°K/(W m-2). (Corresponding to ΔTx2=1.3±0.4°). Interestingly, this result is quite similar to the so called “black body” (i.e., corresponding to a climate system with feedbacks that tend to cancel each other).”
Jan Pompe – “equiv BB temp = (Q/s)^.25 = (342/5.67E-8)^.25 ~ 279K simple arithmetic. It is the same figure for the moon.”
Sorry Jan you got something wrong because from your reference:
“Black-body temperature (K)
Moon – 274.5
Earth – 254.3
Ratio – 1.079”
I think despite saying previously that the Earth or moon are not perfect black bodies you are using the black body calculation without taking into account albedo or emissivity.
Rabbett; “More precisely we know that it has only changed a teensy amount, not enough to account for the observed changes at the surface.”
Jan: Precisely how do we know that?
We know the amount of change from satellite measurements. This is not enough to change the surface temperature and the amount of outgoing longwave radiation.
Rabett: “There have been significant changes in the radiative properties of the atmosphere”
Jan: Precisely how do we know that these changes and temperature changes have not had a common cause? The appears to be a slight loss of correlation with at least one of these supposed radiative properties and temperature of late.
One of the problems with denialism of all sorts is you have to embrace Sgt. Schultz nihilism.
Halpren dropping in to spout nonsense. Like I said global reach.
Josh you planning to include halogens in your well mixed atmospheric climate models any time soon?
Ender: “Moon – 274.5”
= 1.2C QED.
Moon – 274.5 s/b 274.3 = 1C
Rabbet: “We know the amount of change from satellite measurements.”
And I’ve noticed some disagreement between PMOD which appears to be your favourite and the figures from ACRIM from the people responsible for the data.
“This is not enough to change the surface temperature and the amount of outgoing longwave radiation.”
Like I asked how do we know that?
Rabett: We know that over the past 30 years the rate of energy coming in (the total solar insolation) has not changed. More precisely we know that it has only changed a teensy amount, not enough to account for the observed changes at the surface.
James: No we don’t. The insolation changes from one minute to the next. Clouds reflect energy back out into space without the light ever being converted to IR.
Right after you install that Halogen module, you really aught to do something about modeling clouds. After all they are the main building block of weather. Sort of embarassing claiming confidence in a climate model that does model the main component of weather. Maybe that’s why you Giss boys hide your real names while out in public.
In the Rabett universe Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, not to mention various and sundry moons in states of slow disintegration,
are warming for no particular reason.
Strange place he live in.
Ender I should also mention neither the Earth nor moon BB temperature match the theoretical BB temperature but then the neither the moon nor the earth are black bodies. The moon which has no water vapour or CO2 to speak of is closer to the theoretical BB temperature.the earth which has heaps of water and CO2 and clouds is a long way from it.
Gotta love Jupiter. Three red spots now. You gotta love a planet that does climate changing you can actually see.
Josh, here’s a request from an honest to God citizen (you remember those guys who pay your bills right?), how about doing some work in space for a change? A weather map of Jupiter with temperature change isobars would be nice.
Now get out there and earn your money.
So from your reference Jan – (Earth 254.3-273.15 = – 18.85)
Luke,
I have been away for a while, but find that you have obviously not done the homework I set you on another thread. Perhaps it was too difficult for someone trained, rather than educated, in a system which has lost the tools of learning (see Dorothy L. Sayers’ 1947 talk at Oxford, in essay form on the web). I hasten to add that your poor education is not your fault. As Dorothy put it, we have been living on educational capital since we abandoned the Medieval trivium, and the bank account is nearly empty.
Start by looking up ‘epistemology’ in Simon Blackburn’s Oxford Dictionary of Philosophy. Then move on to Ted Honderich’s Oxford Companion to Philosophy, in particular the section on ‘scepticism’.
As a dabbler in mathematics (cook book statistics at least) you should explore the fate of Euclid’s Fifth Postulate after Lobachevsky, Bolyai, and Riemann made their contributions to human knowledge. Oooer! Manifolds in any dimension space.
Don’t bother with any of your usual smart-arse attempts at a put-down. They have as much effect on me, and others probably, as an email offer of untold wealth from a Nigerian princess. You would do well to abandon that approach.
I am green (since the 1940s), and usually slightly left of the political centre, without being a fanatic on either issue. I am a convinced sceptic, if that is not too oxymoronic. Is there such a thing as scepticism about scepticism? Thinking about thinking – ah … that’s the stuff. The poetry of science.
P.S. Don’t forget to look up Neurath’s Boat. If you will pardon the mental image, have a look at Popper’s Piles too.
Luke:
So from your reference Jan – (Earth 254.3-273.15 = – 18.85)
You don’t get it do you? 254.3 is the BB radiation with GHG temperature not the the theoretical one without GHG and calculated from radiation as measured from above the TOA as such it’s not really a BB temperature but a grey body one. The moon’s actual is a lot closer to the theoretical as we would expect from a planet without an atmosphere.
Jan Pompe – “The moon which has no water vapour or CO2 to speak of is closer to the theoretical BB temperature.the earth which has heaps of water and CO2 and clouds is a long way from it.”
I am very confused now. So you are saying that there is such a thing as the greenhouse effect? Perhaps you can have a quiet word with cohenite who seems to think that there isn’t.
ender: “So you are saying that there is such a thing as the greenhouse effect?”
No such thing I’m pointing out the inconsistencies in the theory.
It’s like everytime I run into Halpern he is trying to smack around a girl. This time it’s Jen, last time it was that 12 year old. What is her name? She did a website called Ponder the Maunder.
Anyways, Josh I’m starting to detect a pattern of behavior.
If we ever meet, I’m going to smack you before I say hello.
You deserve it.
Ender: “Is the surface temperature of the Earth more or less constant over long time periods?”
A project of mine 20 years ago was to create a furnace to fire ceramic circuit boards. It was 20 odd feet long, insulated, open on either end of the conveyor, with about as many heaters controlled by AD/DA via an AnalogDevices MacSym computer–color GUI in multi-tasking Basic on CPM. Boards were ramped up to 500C and down.
The controlled temperature within was a chaotic fractal quantity; graphed over time it appeared sinusoid but changing the scale up or down by an order of magnitude revealed the same sinusoid! Say a few degrees C total variation.
Answer: Not a chance, no how, no way you do as well in situ. We damp the measurement digitally so it converges to something on your meters.
James – this an evidence based blog – where’s your references for Mars, Jupiter, Saturn, Uranus, Neptune, Pluto warming?
And what do the trends in the International Satellite Cloud Climatology Project say?
Don’t just speculate mate?
And what is your specific objection to the way clouds are represented in climate models.
Time to grow up and stop behaving like an ex-Californian flower child
James – she wasn’t 12 – you’ve confusing things with your own life.
Jan – crap – prove it.
Luke: “she wasn’t 12”
She was 15 some difference.
prove it. Have done see response to Ender. the physics is simple you also see it the link that Ender provided to nir Shaviv’s site.
It is clear that the calculations involve grey body for incoming and black body for out going. A fundamental flaw in the hypothesis.
You have albedo changing clouds without cloud causing water vapour :- it’s rank nonsense and this much is obvious from the BB temp of the moon which is subject to the same energy source as the earth.
Luke you want to see evidence, buy a telescope and have a look at Jupiter.
It’s up there.
A 1500 mm glass will show all three red spots with a 9 mm eyepiece.
Jan – “It is clear that the calculations involve grey body for incoming and black body for out going. A fundamental flaw in the hypothesis.
You have albedo changing clouds without cloud causing water vapour :- it’s rank nonsense and this much is obvious from the BB temp of the moon which is subject to the same energy source as the earth. ”
Your waffling again Jan. It is not clear at all from the calculation that anything of the sort that you say is happening is true. Nir uses the albedo and emissivity modified equations for incoming and outgoing radiation.
Where exactly is the flaw? Did Nir get it wrong as well?
Ender: ” Nir uses the albedo and emissivity modified equations for incoming and outgoing radiation.”
Not exactly he sets albedo and the non controversial .3 and the emissivity at 1 just like every body else other wise this statement “Below, we’ll try to understand where this number comes from,”
would not be true he would be doing something else setting emissivity to something line .7 would actually be far more realistic but no one does it. IMO they should.
ender; you keep verballing me; I said the Greenhouse concept is dumb and I provided you with a link above which nicely examines the fault with the analogy; it is the concept of the greenhouse and its GHG’s, and uniform temps and gas mix, which has been sold to the public and it is a con; you keep badgering people to admit that the GHG’s intercept the outgoing radiation and provide the warmth to produce a temp above a BB pristine temp; Jan has answered most of your spurious distractions, and I have alluded to the impurities in the surface and atmosphere of the earth which prevents such a simplistic scenario from occuring; but the kick is, even if you and the prof were right, and the extra CO2 is like a extra pair of flannelette undies on the earth, the -ve feedbacks are taking off the gear as fast as CO2 can cover up; think of it as being like a perpetual seduction which gets nowhere until something like Milankovitch occurs; the don juan of the climate cycle.
Jan – So we started this with:
“””When the Earth warms, it emits more infrared radiation to outer space. This natural cooling mechanism is the same effect you feel at a distance from a hot stove. The hotter anything gets the more infrared energy it loses to its surroundings.” makes no sense.”
Makes perfect sense Q = esT^4
q = heat loss rate, e = emissivity, s = stefan-boltzmann constant, T = temperature. It’s pretty well established theory.”
And now we have you correctly saying that the Earth when it is warming is acually emitting less radiation than it is receiving due to the fact that it is not a perfect black body but a grey body that is subject to emmissivity and albedo constraints.
In this case the greenhouse gases change lower the emmissivity by trapping some of the IR radiation from the surface.
In response to this the surface warms thereby increasing its emmissivity back to the point where it again balances the incoming radiation.
So what you said initially was crap and what Eli said was accurate unless of course you would like to void all your recent statements.
cohenite – “I said the Greenhouse concept is dumb”
Ok then you should be talking to Jan not me. He seems to understand the concept. I just suggested that he tutor you in basic physics off line so you don’t embarrass yourself.
If you really want to keep going then if the greenhouse concept is dumb why is the Earth’s average global temperature not 254K? Jan has already provided the mechanism so if you have trouble with this question you can ask him.
Ender: “In this case the greenhouse gases change lower the emissivity by trapping some of the IR radiation from the surface.”
Clouds do much more to lower overall emissivity and lower absorptivity by increasing reflectivity. CO2 and water vapour actually increase atmospheric emissivity along with absorptivity and really have little effect on surface temperatures. It’s that one sided taking albedo in account an ignoring the lowered emissivity that comes with it and the taking of GHG absorptivity into account and ignoring emissivity of GHG, in both cases it basically symmetrical, that’s leading to the nonsensical conclusions that we are seeing.
Utterly unacceptable Jan & James – sick of your opinions. I want evidence.
Luke: “I want evidence.”
It’s in the world around you look around you sometime. If you can’t understand text book physics and text book spectrometry then I strongly suggest you take up some study and learn. I can however give you this from Grant Petty’s “A First course in Atmospheric Radiation:
http://i165.photobucket.com/albums/u43/gplracerx/PettyFig8-2.jpg
Looking down you see the absorption bands of CO2, H20, and O3 and the proof that these polyatomic also have high emissivity compared to the other species is the lower chart looking up you see the emissivity in the very same bands the more pronounced being O3 and CO2. What you also see there is the CO2 is emitting at the BB intensity for the temperature it’s at and that temperature is the same as at the surface ie it’s in thermal equilibrum. The surface is not at that time warming the boundary layer of atmosphere nor is the atmosphere warming the surface.
Don’t think so – http://www.exploratorium.edu/climate/atmosphere/data2.html
Jan – “Clouds do much more to lower overall emissivity and lower absorptivity by increasing reflectivity. CO2 and water vapour actually increase atmospheric emissivity along with absorptivity and really have little effect on surface temperatures”
So the Earth should be colder that it’s black body temperature if these things increase emissivity as the Earth has lots of these. In this case the Earth would be radiating more that it receives so it would have to cool down to balance the radiation once more.
How do you reconcile your statements with the observation that the Earth is warmer than its predicted black body temperature?
Luke
Your link restricts istself to radiant energy, ignoring EM.
There is much more to this than your candle powered anachronism.
Measurement Ender, measuremnet.
Your own stats support that.
Ender: “So the Earth should be colder that it’s black body temperature if these things increase emissivity as the Earth has lots of these.”
it also increases absorptivity so that e = 1 -a and you end up with the black body result i.e. no change from the BB emission.
Te^4 = ((1-a)/e) s Teq^4 where Teq is BB equivalent source temperature. Doesn’t matter whether we are talking sun or planetary surface.
The difference between absorptivity and emissivity is insignificant so they cancel and their effect is negligible unless you set either on to 1 and leave the other at <1 which is what they do.
For example
http://arxiv.org/PS_cache/arxiv/pdf/0802/0802.4324v1.pdf
in equation 12 you see the emissivity {espilon}_eff in the demoninator then in 14 and 15 it’s left out effectivily setting that to 1 and a (albedo ) remains ~.3 so absorptivity remains ~.7.
“ow do you reconcile your statements with the observation that the Earth is warmer than its predicted black body temperature?”
If that really is the case, and remember it’s a such averages are physically meaningless, then the earth is shedding heat. Time will tell whether it is or not. Bear in mind there is an enormous amount of heat stored in the ocean still to be lost.
Luke: “Don’t think so”
Your link does not address the points I have made nor the evidence from a well accepted text book that the atmospheric polyatomic gases emit as well as the absorb. Nor does it address the fact that everybody notices that cloudy nights don’t get cold as fast as clear nights meaning clouds are as adept at bouncing IR as they at bouncing white light.
Now would you like to try a little harder.
Nope on average, and explicitly spatially, a vast amount of the incoming shortwave radiation is bounced straight back. Average albedo of 0.3.
Conversely the longwave satellite observations also bear that out. http://www.exploratorium.edu/climate/atmosphere/data1.html
Ender: I suspect what I’ve written wont quite make sense to you. In any case the way I’ve written it will produce too much cooling. So:
An effective BB temperature that is determined by radiative output from the planet of 254K provides a radiation of 236 W?m^2. Now that is with that emissivity of 1 that I’ve been complaining about. Now if the emissivity was about the same as absorptivity i.e. .7 the same emission would be achieved with a planetary temperature of
278K which puts is in the ball park of the 279K which is the equilibrium temperature we’d expect of a black body in earths orbit. Here we really only have to account for 9K instead of 33K.
BTW the 236w/m^2 outward radiation is not too different from the incoming with albedo taken into account (238.7) so the balance is roughly right but I don’t think that 33K can be attributed to GHG but a figure a lot less of about 9K which will put climate sensitivity to CO2 doubling much lower.
luke; what exactly are those interesting maps you link to supposed to prove? The areas with greatest albedo are not the areas with greatest LW emissions from the earth?! Note that the areas of greatest LW emissions are at the equator over the oceans. As has been noted before, the oceans are the great thermostat of the earth, not the gases that ender is preoccupied with
Ender; do you know what Beer’s Law is? If not, research it and explain it to luke and the prof.
Luke “a vast amount of the incoming shortwave radiation is bounced straight back. Average albedo of 0.3.”
I am well aware of that what you seem unable to understand it’s only part of the story. Every silver lining has a grey cloud underneath that bounces vast amounts of IR back to the surface.
What effect does the reflected shortwave have on the Earth’s temperature?
And no – the greatest longwave flux is over the deserts – see Arabia
http://earthobservatory.nasa.gov/Observatory/datasets_monthview.php3?product=lwflux.erbe&year=2005&month=6&firstyear=1984&lastyear=2005
I wouldn’t say the greatest, certainly the most intense over a relatively small area; that’s spooky. Whatever manhattan project is taking place there still doesn’t detract from my point though.
Luke: “What effect does the reflected shortwave have on the Earth’s temperature?”
It cools it. Now what does effect does reflected long wave have on surface temperature?
“And no – the greatest longwave flux is over the deserts – see Arabia”
Nope over the Indian Ocean interesting but note the where the highest SW flux due to clouds is the lowest LW flux. The reduced diurnal temperature range in cloudy conditions is well known.
Nope – looks Indian Ocean blue to me http://earthobservatory.nasa.gov/Observatory/datasets_monthview.php3?product=lwflux.erbe&year=2005&month=6&firstyear=1984&lastyear=2005
And how does the reflected shortwave cool the Earth?
Did it ever warm it?
Nope – looks Indian Ocean blue to me
not here
http://www.exploratorium.edu/climate/atmosphere/data1.
And how does the reflected shortwave cool the Earth?
The earth needs constant SW incoming to maintain the temperature so reflecting allows it to cool. Understand? Now stop the silly semantics and tell us what bouncing LW IR back to surface has on the temperature.
(and yes I appreciate the issue with clouds SW and LW)
Your point – reflected longwave – “reflected longwave – or emitted longwave? – the warmed surface of the Earth will emit longwave and also receive some reflected longwave from clouds and “ooooo greenhouses gases”.)
Must say the Arabia issue – makes you think a bit – area would have higher albedo (brighter) too…
Well depends on what month – and where clouds are does it not.
Anyway – silly semantics – well that’s what I’m thinking about your comment.
The reflected shortwave does not cool the Earth IMO – simply the Earth does not absorb as much radiation (to inevitably emit as longwave). it never warmed it to begin with. It’s the same effect as being further away from the Sun. Simply less incoming radiation in effect.
That is assuming the atmosphere is transparent to and does not interact with shortwave.
Which is why I don’t understand your whole problem with albedo !
Luke: “Which is why I don’t understand your whole problem with albedo !”
Of course you don’t because I don’t have a problem with albedo. I suspected you were pretty thick but not quite this thick.
Problem is with clouds they reduce incoming i.e. absorptivity the also reduce outgoing i.e. emissivity on should take both effects into account if one is to make a rational accounting of energy absorbed and energy emitted.
Did you notice how Luke never asked for evidence from Josh?
Heh.
Did you notice how Eli made a simple point to Jennifer, and how she accepted it?
Eli certainly was not picking on her, just explaining something that often confuses people. This appears to have displeased some. YMMV
eli, prof, josh?; there are more secret identities on this site than at Gotham City. With all this talk about BB’s and GB’s and sensitivity, I’m wondering why nobody has referred to Arthur Smith’s ‘rebuttal’ of the Gerlich paper, and obstensible reinstatement of the ‘greenhouse’ concept? Smith deals with all the issues, albedo, radiative exchange, emissivity and absorbtion, or lack thereof; one of the problems I have with Smith is that he only allows for minute internal energy contribution from radiactive decay and gravitational tidal forces; I would have thought tectonic activity and ocean recycling generated and used some energy; but most of all he ignores the energy storage capacity of the oceans; this is apparent when Smith states “While the variability in infrared emissivity is relatively small across the surface of a realistic planet, the albedo can be significantly different from place to place.” As luke’s great maps show this is not right; and anyway, as a matter of logic, if albedo varies, then so must emissisivity because the albedo variation determines what sw gets through to be converted to LW; Smith cleverly overcomes this by asserting that regional differences in albedo can be treated as the same as uniform albedo (33); this is unreasonable! Finally, Smith assumes that re-emission is randomly directed, “half the radiation from this atmospheric layer will go up, and half down”; as you explained to me prof – can I just call you Batman? – the up/down configuration is not that simple because of the different things that happen from ‘layer’ to ‘layer’ and lateral movement, and most importantly LW windows, as, once again, luke’s wonderful maps show.
Jan you are an obscurantist.
Jan there is one thing we learn from you now mate. You never answer the question. You never expound. You never explain. All you do is quip. Dodge and weave with half answers. So are we any the wiser – nope.
Well Eli was satisfying and comprehensive in his responses which you guys never are.
Jan I’ve asked you a really basic question on shortwave and you’ve ducked it. I know why.
Well Cohenite – you are the pinnacle of hypocrisy – someone named after a meteorite? Is that your first or last name? Dr Rock? Mr Rock. Wouldn’t be involved in research down Newcastle way yourself perhaps? Who cares if you name is really Bush or Gandhi – the issue is content and what you have to say (unless you’re using your fame as some barometer of standing).
It’s hilarious how many on here ack “warmers” who may prefer to use non de plumes while ignoring their own mates and even themselves in the process. Yea Gods !
What is a good barometer though is that when the ID issue comes up you know the opponent is worthy – it’s great index of opponent quality.
All the maps do is (1) bring you guys back to some ACTUAL numeric measurements (assuming the satellite is right) (2) a view of spatial reality – what’s a bright surface, where clouds are often, the equator gets a lot of sunshine, and the Earth’s climate has seasons?
luke; don’t be snarky; I rather enjoy sobriquets and I hope my suggestion to the prof is taken in the spirit is was offered, since from my vantage point he is a bit of a “Dark Knight”; my own has a rather dull history to do with a social commentator called Nic Cohen; I’m afraid I missed the meteorite connection completely, but I’ll gladly claim it.
As to your maps; they, apart from the odd thing over the ME, really work against you for the reasons I’ve offered; there is no question that low-level clouds cool, even if the mechanism is a bit unclear; here are 2 links which establish that;
http://www.agu.org/pubs/crossref/2004/2003GL018765.shtml
http://www.jennifermarohasy.com/blog/archives/002914.html
The first is your good friend Philipona; not only does the study show, by inductive reverse logic, that clouds cool, but that the heating has only a small ghg effect.
Jan – “Now if the emissivity was about the same as absorptivity i.e. .7 the same emission would be achieved with a planetary temperature of
So how does the emissivity get to 0.7 instead of 1?
I can’t see how the emissivity magically gets to 0.7. I can if you accept the actions of greenhouse gases and that they play a part in getting the emissivity down to this value.
So perhaps you can explain yourself and suggest, with references, another mechanism.
So far the accepted theory, that of greenhouse gases is passing all the tests of matching predictions with observations and measurements.
Ender: “So how does the emissivity get to 0.7 instead of 1?”
Same way albedo gets to ~.3 – clouds. They stop IR radiation. It might not be exactly .7 but but then neither is albedo and it certainly isn’t 1.
Cohenite – drat – you know me too well. Anyway – I say again it would be great to get a fullsome guest post from yourself on this whole issue of the details of greenhouse physics from quantum level to radiation budgets.
Wish Eli would do the same for us. I learnt more from him in 2 paras than in the last 2 months.
There is a whole mess of physics arguments here which are frustrating the hell out of me. And we never get a proper story laid out. Just quips and bit n’ pieces.
And for some more – different types of clouds do different things in terms of radiative forcing and changes in cloud trends are not uniform. http://meteora.ucsd.edu/~jnorris/presentations/cloud-aerosol_files/v3_document.htm
Luke: “So are we any the wiser – nope.”
Then you should check between your ears for the problem.
obscurantist
Luke: “obscurantist”
Only to the terminally thick.
Says the unpublished nurses aid.
Luke: “Says the unpublished nurses aid.”
More display of Luke’s arrogant ignorance.
Luke: I reckoned wayback cohenite was salvageable, more so now as he seems to have also missed that nic connection to a certain hard faced Liberal position. Jan on the other hand is destined to melt away like the unfortunate lad Icarus.
Jan – “Same way albedo gets to ~.3 – clouds. They stop IR radiation. It might not be exactly .7 but but then neither is albedo and it certainly isn’t 1.”
So clouds are the only things that trap IR? What about the places where there are no clouds for most of the time? So what you are saying if there were no clouds then the Earth’s global average temperature would be approx 254K?
Also how are you going to reconcile this, assuming it it true, with the cosmic ray theory that postulates that more sun activity -> less cosmic rays -> less clouds -> warming?
Eli: This appears to have displeased some.
James: Not so much. I have a general residual disdain for James Hansen’s small cadre of online minions in my personal climate pipeline. Consider it a PDO which will never shift. You should have some experience with that. Heh
June is in the books. Eli, don’t you have some temperature readings to fudge???
Gavin: “Jan on the other hand is destined to melt away like the unfortunate lad Icarus.”
Not likely because unlike you I had sense enough to keep away from the doors when they opened them on the open hearth furnaces. Never tried to use my body as a thermometer.
Ender: “So clouds are the only things that trap IR?”
It’s the only thing relevant when taking into account that they are the source of albedo. That is to say one should not be worrying about the one without the other i.e. one must take into account the entire radiative effect of the clouds not just half of it.
You seem to have some difficulty with this.
“So what you are saying if there were no clouds then the Earth’s global average temperature would be approx 254K?”
No clouds, no water AND no GHG at all (O2 and N2) do have some collision induced absorption in the Far IR so they must go too then we have the same conditions as the moon which sits at 254.
Obviously if there is no water there will be no water vapour and hence no clouds so the cosmic rays won’t have anything to work on – just like the moon.
Ender – funny this doesn’t happen on Earth.
http://www.lunarpedia.org/index.php?title=Lunar_Temperature
For a surface with the sun directly overhead, for example a horizontal region near the equator at lunar noon, I is the solar constant in Earth’s neighborhood, about 1366 W/m^2, minus the portion reflected. Since the emissivity is close to 1 minus the reflectance, those two terms cancel out, and inverting the equation gives the maximum day-time high on the Moon: 394 K or about 120 degrees C.
During the night the surface temperature drops further as the rocks radiate away the energy they’ve absorbed during the day time, with regions near the lunar equator dropping to about 120 K or -150 degrees C by the end of the night.
The temperature drop is limited by conduction of heat from layers several meters below the surface, which maintain a roughly steady average temperature that can also be determined from the Stefan-Boltzmann law. In this case ‘I’ represents the incoming solar energy averaged over a full day-night cycle
Iave = 1366cos(θ) / πW / m2
so at the equator T is about 296 K, or a comfortable 23 degrees C if you bury yourself sufficiently. At 60 degrees that drops to 249 K or -24 degrees C. The average subsurface temperature near the poles (85 degrees and higher) would be below 160 K or -110 degrees C
Jan – “It’s the only thing relevant when taking into account that they are the source of albedo. That is to say one should not be worrying about the one without the other i.e. one must take into account the entire radiative effect of the clouds not just half of it.”
So the water vapour in clouds also traps IR? What about the water vapour we cannot see – does that trap IR also?
Also I am pretty certain that the albedo effect is what Luke is saying and is mainly the reflection of SW radiation straight back into space. If you want to advance the cosmic ray theory then this is more consistent with its assumptions than yours that clouds do all the IR trapping.
“Obviously if there is no water there will be no water vapour and hence no clouds so the cosmic rays won’t have anything to work on – just like the moon.”
However what you are saying, that clouds do all the IR trapping, is diametrically opposed to the cosmic ray theory. So how do you reconcile this?
gavin; thank you for your kind words, but I’m afraid I’m already gone; at the end of the day I’m still a lawyer.
Jan; may I call you Icarus? That reminds me of the tale about Hathaway who wanted to find out why the sun was fading, but he had to be back before sunrise. Anyhow, I’m glad you raised N2 and O2, which between them constitute 99% of the atmosphere; it seems to me they pick up some heat through conduction with the planet’s surface; I wonder what happens to that heat?
Ender: So the water vapour in clouds also traps IR? What about the water vapour we cannot see – does that trap IR also?
Yes and no. It absorbs IR and shares the energy with other species while some people call this trapping I think it creates a wrong impression because it radiates it as well and once the atmosphere is in thermal equilibrium at the same rate it receives it in all directions. Hence it only “traps” it until thermal equilibrium is achieved then it just hands it off to the next layer and so on.
Clouds reflect (and scatter and absorb some) infrared just like they do with SW incoming so the overall effect is that they raise albedo AND reduce absorbance AND reduce emissivity.
I’m not interested is cosmic ray theory I think it’s still far from proved even though there is some persuasive data about any suggestion that I’m about advancing cosmic ray theory amounts to a strawman red herring. Forget it.
Jan – “Hence it only “traps” it until thermal equilibrium is achieved then it just hands it off to the next layer and so on.”
However that is exactly what we have been saying. If the greenhouse gases trap the IR then it does not make it back out to space as it is transferred to other molecules as you said.
The more you say, the more you are confirming the greenhouse gas idea of warming.
To summerise, you agree thatthe Earths emissivity is lowered by clouds and greenhouse gases such as water vapour. So theoretically, to maintain its radiation balance, the Earth must be then warmer to emit sufficient energy through the layers of clouds and greenhouse gases so that the incoming energy balances the outgoing. Scientists have indeed confirmed by direct observation that that global average temperatures are warmer than then black body temperature by an amount consistent with the measured and observed energy flows. So the prediction is confirmed by observation.
You have to agree with this as it is a summary of your recent comments.
Ender: “The more you say, the more you are confirming the greenhouse gas idea of warming.”
Don’t mistake for some who thinks the presence of CO2 has no effect this is not the case I don’t think the effect is as great as that put about IPCC and the like. CO2 (and water vapour) in the atmosphere makes the air a lot more comfortable than it would be without it but I expect that the effect on the solid surface temperatures will be minimal <1K/2xCO2 is as low and high as I’m prepared to go for the reasons mentioned above.
ender; I have just the paper for you; it is by Peter Dietze; in it he compares clear sky and cloudy sky forcing, and looks at the effect of vapor and the Svensmark factor and cosmic rays;
http://www.john-daly.com/forcing/moderr.htm
Try not to go the ad hom with Dietze who has a masters in engineering.
ender; your fascination with clouds is addressed in this paper which compares CO2 forcing in clear-sky and cloudy-sky conditions, and also looks at the crucial role of vapor, and for good measure the Svensmark factor and cosmic rays;
http://www.john-daly.com/forcing/moderr.htm
cohenite: Dietze, based on the Daly site can hardly be neutral. Let’s say some other engineering types don’t bother with it.
Folks: If I had to catch up again, the first place to look is here –
http://www.johnwiley.com.au/trade/engine.jsp?page=browseTitles_l3&pt_banner$acecode=CHXXXX&acecode4$acecode=CHXXXX&all$sacecode=CH0300
Then –
http://www.johnwiley.com.au/trade/engine.jsp?page=browseTitles_l3&pt_banner$acecode=CHXXXX&acecode4$acecode=CHXXXX&all$sacecode=CH0600
And so on –
Reckon it would take a while?
Jan said that greenhouse gases only trap until thermal equilibrium is reached and then the radiation is handed off to the next level.
This is not true. You can see that this is the case by looking at emission spectra at various levels, for example in this figure, you see that the blackbody equivalent temperature in the CO2 absorption region is about 220 K, while that in the clearer windows is about 290 K, a leaky trap, but a trap all the same.
“The more you say, the more you are confirming the greenhouse gas idea of warming.”
Only in a very simplistic model. If more CO2 in the atmosphere causes less moisture, then there does not need to be warming. It’s the amount and balance of all greenhouse gases that makes the difference. You cannot treat the addition of CO2 in an isolated manner, and you cannot assume that the addition of CO2 will increase the amount of moisture. It may in fact decrease the amount of moisture.
Eli: “for example in this figure, you see that the blackbody equivalent temperature in the CO2 absorption region is about 220 K, while that in the clearer windows is about 290 K, ”
Which figure was that?
This one?
http://i165.photobucket.com/albums/u43/gplracerx/PettyFig8-2.jpg
these are coincident downward and upward reading in the CO2 band shows BB equivalent temperature 268K and the downward clear areas it’s also 268K indicating the surface layer is in thermal equilibrium with the surface. A certain amount of the energy absorbed is converted to kinetic energy which is heating the atmosphere which causes the warmed parcel of air to rise. Some kinetic energy is thus being converted to potential energy which does NOT contribute to radiation but the KE that remains does. Therefore we will have less radiation the higher we go from CO2 because there is less KE to radiate but nothing is being leaked it is being used.
r
Jan; beautiful; but I assume you mean the surface layer is in thermal equilibrium with the ‘atmosphere’?
“Therefore we will have less radiation the higher we go from CO2 because there is less KE to radiate but nothing is being leaked it is being used”
And you know this how?
And sorry for forgetting you prof;
“You cannot treat the addition of CO2 in an isolated manner, and you cannot assume that the addition of CO2 will increase the amount of moisture. It may in fact decrease the amount of moisture.”
Indeed Minschwaner and Dessler provide the theory for that, while NOAA has provided the detail with relative humidity falling at pressures of 925mb or above; below that, increases in low cloud cover, another Miskolczian -ve feedback, are producing the increase in moisture. So with Kirchhoff put to bed by Jan, and the prof on board with Miskolczi, the stinking corpse of AGW can be entombed in the Erhlich mausoleum of failed doomsday scenarios.
just spat more coffee over a new keyboard. Blogging is expensive.
Ender: “And you know this how?”
Law of conservation of energy is well established.
cohenite: “but I assume you mean the surface layer is in thermal equilibrium with the ‘atmosphere’?”
Each layer is in local thermal equilibrium, which is actually an approximation, with the one above and below and that includes the solid surface with the skin layer.
You can even see it in a MODTRAN simulation downward looking at 100m where the BB radiation in the window as at the surface temperature and that in the CO2 absorption band it’s due to emission from CO2 at the same temperature.
http://i229.photobucket.com/albums/ee272/JanPompe/rad29193535.gif
“Law of conservation of energy is well established.”
That doesn’t explain anything that you are talking about.
“Each layer is in local thermal equilibrium, which is actually an approximation, with the one above and below and that includes the solid surface with the skin layer.”
Makes me think you have no idea what you are talking about, you seem to be at some stage of understanding that has not reached to the level of Calculus yet.
Ender: “That doesn’t explain anything that you are talking about.”
Perhaps not to you but I didn’t expect that it would.
for a constant entropy
dQ = dU – dW
dQ is the energy input dU is the change in internal energy dW is the energy required to do work (for example convection) nothing is lost it can’t go anywhere except out. The radiation form the atmosphere is proportional to the 4th power of temperature or if you prefer the 4th power of it’s average kinetic energy now the higher you go the more of this kinetic energy has been converted to potential energy which does not contribute to the radiation this is the “leak” Rabbett is talking about but as you can see it’s not a leak.
As the parcel of air sinks it regains the kinetic energy from potential energy.
Jan, if you are at 20km looking down almost all of the atmosphere (molecules)is below you. You see about the same thing at 100 km looking down.
Rabbet “Jan, if you are at 20km looking down almost all of the atmosphere (molecules)is below you. You see about the same thing at 100 km looking down.”
I know you “see” the same thing at 70 km looking down but is it really the same think you are looking at. At 20 km you are looking at and seeing in the window the surface radiation barely modified and that would be the similar at 70km but wrt 15micron band we are looking at the radiation from CO2 at different heights to a depth of a few metres because of the atmospheric opacity in that band. Strangely enough the temperature at around 70km is very similar to the temperature at 20 km, so perhaps we aren’t really seeing the same thing at all. We can’t even see the thermal radiation due to the higher temperature at the stratopause in the 15 m icron band.
Now that rather boring trivially obvious lot is not really relevant. Looking down from 20 km you see the surface radiation in the window which is at the BB equivalent of 268K the upward one shows the same temperature driven radiation from the CO2 absorption band meaning the temperatures are the same. That the downward looking radiation at 20 km for the CO2 band is ~220K hardly surprising as that is about the temperature of the tropopause where the kinetic energy has been converted to potential energy.
So start at the bottom and work your way up in 1 km increments, look up and down. You might learn something like the radiation from lower levels in the CO2 bands does not get out to space, e.g. it is blocked
Rabbett:So start at the bottom and work your way up in 1 km increments, look up and down. You might learn something like the radiation from lower levels in the CO2 bands does not get out to space, e.g. it is blocked
It doesn’t get blocked it gets diverted some gets used before being radiated off to space e.g. something had to power my sailboat.
What we see in the upward looking chart is that the atmosphere radiates very well in bands where there are polyatomic atmospheric species with resonant vibration modes not so well where there aren’t. Without them the atmosphere will take quite a bit longer to cool but then without them the atmosphere would probably not warm as fast or as much.
Without polyatomic my sailboat would probably never have worked but then we would be here either and would it never have been built in the first place.
Not really. The largest changes are when you look up. For one thing the water vapor concentration and absorptions change radically. There is practically none left at 15 km. That is the lapse rate at work as the saturated vapor pressure of water vapor decreases with temperature. You will notice that there is a lot less emission from CO2 as the altitude increases, and if you look closely you will see that the width of the band decreases.
Looking down you will notice that there is practically no absorption at 100 m, and the CO2 and water bands grow in with altitude. This is because the layers near the surface are practically at the same temperature as the surface so the atmosphere appears transparent with equal amounts of absorption and emission. As one goes higher there is more absorption than emission, so the window closes.
For those who wish, the application to see these things is at
http://geosci.uchicago.edu/~archer/cgimodels/radiation.html