Guest post by Bob Irvine
SUMMARY
This paper outlines an idea or hypothesis that should be discussed. This idea has the huge advantage of being supported by all the available data both from over the last thousand years or more, the last 60 or 70 years and the last 20 years.
We have a chance here to solve the global warming debate and standoff. It is quite possible that both sides of the debate have some truth on their side. I believe there is a strong case that the climate sensitivity or temperature response to a given forcing not only depends on the size of that forcing but also on the nature of that forcing. I have attempted to mount a case for the idea that a given LONG WAVE GHG forcing will have considerably lower temperature response than a similar SHORT WAVE solar forcing.
The alarmists may well be correct. There is a lot of evidence from the Last Glacial Maxima and Volcanoes and other areas that climate sensitivity is quite high (about 0.8, i.e. requil. T=0.8xrF). Certainly, this can be seen on geological scales. These estimates are based on Short Wave Solar Forcings. The trouble starts when they try to apply these high sensitivities to the enormous increase in Long Wave GHG forcing that has occurred in the last 60 or 70 years. They mistakenly assume that a given GHG forcing will have the same equilibrium temperature response as a similar Solar Forcing and then find it difficult or impossible to make the meagre temperature response over recent years fit their high sensitivities.
The riddle is neatly solved if we accept the concept of “Effective Climate Forcing”. In other words, we accept that a given Long Wave GHG Forcing has a lower climate sensitivity than a similar Short Wave Solar Forcing. It is in fact intuitively unlikely that these two forcings have the same efficacy as is assumed by the IPCC and others.
INTRODUCTION
The efficacy of a given forcing is an estimate of its efficiency in provoking an equilibrium temperature response in the earth’s system. The IPCC and others assume that a given change in GHG forcing will produce a temperature response that is approximately equal to the temperature response from a similar change in solar forcing.
That this is not necessarily the case is discussed in the literature. Joshi et al 2003, Hansen and Nazarenko 2004 and Shine et al 2003 all conclude that the same forcing can have a different temperature response depending on its nature or geographic location.
Forster and Taylor 2006, “Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations “ make the case that ”Effective Climate Forcing” is a much more useful way of estimating climate sensitivity than conventional; one size fits all, Radiative Forcing. They make their case succinctly in the following quote;
“Imagine, for example, that the atmosphere alone (perhaps through some cloud change unrelated to any surface temperature response) quickly responds to a large radiative forcing to restore the flux imbalance at the TOA (Top Of Atmosphere), yielding a small effective climate forcing. In this case the ocean would never get a chance to respond to the initial Radiative forcing, so the resulting climate response would be small and this would be consistent with our diagnosed “effective climate forcing” rather than the conventional “Radiative forcing.”
In the quote above a shorter response time at the TOA produces a lower climate sensitivity. Hansen, Sato and Kharecha confirm and support this in their paper “Earth’s Energy Imbalance and Implications”, by saying
“On a planet with no ocean or only a mixed layer ocean, the climate response time is proportional to climate sensitivity. ………..Hansen et al (1985) show analytically, with ocean mixing approximated as a diffusive process, that the response time increases as the square of climate sensitivity.”
If it can be shown that the restoration of the flux imbalance at the TOA is quicker for a perturbation in GHG forcing than it is for a similar perturbation in solar forcing, then this would imply a lower climate sensitivity for GHG forcing than solar forcing.
DISCUSSION
It is in fact intuitively unlikely that the earth’s system would respond in almost exactly the same way to a change in Long Wave GHG forcing as it would to a change in Short Wave solar forcing, as the IPCC and others assume.
It is established physics that Long wave Radiation from GHGs only penetrates the oceans to a depth of a fraction of a millimetre. The oceans are virtually opaque to these wave lengths. Short Wave solar radiation, on the other hand, penetrates the ocean to a depth of 10 meters or more and it is counter intuitive to assume that this established fact would have close to zero effect on flux imbalance restoration times at the TOA.
Despite this matter being pivotal to any understanding of the earth’s climate response to increasing Anthropogenic GHGs (AGHG), I have been unable to find any literature supporting the IPCC’s position that solar forcing and GHG forcing have the same efficacy after the ocean/ atmosphere interface has been considered. The references mentioned by the IPCC in their reports only refer to the global nature of the two forcings and only take into account feedbacks that are related to a temperature response. These do not apply in this case. Basically, the fact that the oceans are opaque to GHGs is due to the nature of the forcing and not accounted for if the feedbacks considered are only related to a temperature response. Similarly, to assume, as the IPCC does, that GHG forcing and Solar forcing have the same “effective climate forcing” simply because they are both global in nature, also, does not take account of the opaqueness of the oceans to the wave length reemitted by GHGs.
The blogosphere does make an attempt at explaining the IPCC’s position. The only defence I am aware of is that the top fraction of a millimetre of the ocean is heated up by the Long Wave Radiation (LWR) reemitted by GHGs. This then acts as a blanket slowing the release of energy from the ocean, thereby effectively warming the ocean by nearly exactly the same amount as a similar solar forcing that penetrates the ocean to a depth of 10 meters or more.
Not only is it highly improbable that these two entirely different mechanisms would have almost exactly the same effect on OHC (Ocean Heat Content), but it can be shown by means of a simple experiment, (Appendix 1), that nearly all the Long Wave GHG energy is returned almost immediately to the atmosphere and space as latent heat of evaporation. It, therefore, has little effect on OHC. It is, also, likely that the restoration of the flux imbalance at the TOA is quicker for a perturbation in GHG forcing than it is for a similar perturbation in solar forcing.
It is apparent that the situation described in the Forster and Taylor (2006) quote above is relevant to GHG forcing. In short, the” Effective Climate Forcing” of a GHG change is likely to be considerably less than the “Effective Climate Forcing” of a similar solar change.
CORROBORATION
It is an intriguing possibility that both sides of the Global Warming debate could be correct to some extent. The IPCC and others estimate climate sensitivity by reference to three factors, none of which apply to climate sensitivity derived from a GHG forcing.
These three factors are;
- They use “Absolute Radiative Forcing” instead of “Effective Radiative Forcing” (Forster and Gregory 2006)
- They use sensitivities based on Solar Forcing which clearly do not apply to GHG Forcing. For example, sensitivities calculated from the Last Glacial Maxima (LGM) or volcanoes are essentially based on Solar Forcing and, therefore, do not apply to GHG Forcing. (Annan & Hargreaves 2006).
- They use feedbacks that are dependent on an initial temperature response and, therefore, do not take account of the opaqueness of the oceans to Long Wave Radiation from GHGs. (All the Global Climate Models , GCMS)
The IPCC and others may have produced some good science that gives reasonably accurate climate sensitivity estimates for a change in solar forcing. Unfortunately, these are unlikely to apply to a GHG Forcing.
Interestingly, Idso 98 uses real world experiments that, largely, do apply to GHG Forcing and their climate sensitivity is considerably lower than the IPCC’s consensus.
The sceptics, on the other hand, are fairly obviously quite correct when they say that the high sensitivities postulated by the alarmists do not fit with the measured temperature record of the 20th and 21st century.
The best way to show this lack of correlation is to compare the amount of energy put into the system by human GHGs, as represented by equilibrium temperature, with actual temperature as measured in the thermometer age since 1880.
The green line in Fig. 1 equates to a sensitivity of 0.8 (rT = 0.8 x rF) which gives an equilibrium temperature increase of 3.0°C for a doubling of human CO2, the IPCC’s central position. In 2010 the difference between the green line and blue line (actual temperature) was an unlikely 1.4°C. If present trends continue, as is likely, that gap would be close to 2.0°C in 5 years’ time.
FIG, 1 The IPCC’s upper (purple), central (green) and lower (red) equilibrium temperature predictions using their climate sensitivity to forcing. The forcings were calculated for all the human GHGs using concentrations given in 4AR and the generally accepted conversion formula, rF=5.35xln(C/Co) WM-2 where C is current concentration and CO is starting concentration. These are compared with actual temperature (blue). For comparison purposes all graphs were zeroed in 1880.
NOTE; It is generally believed that equilibrium temperatures are approximately 1.5 times transient temperatures (4AR) and that aerosol cooling has masked any human induced GHG warming. These are the two factors the alarmists use to attempt to explain the gap between reality and the IPCC’s calculated equilibrium temperatures from AGHGs.
There are also major inconsistencies with the Ipcc’s explanation for the warming from 1910 to 1940. Bob Tisdale discusses these inconsistencies at WUWT on the 20th April 2013.
The only realistic explanation for this lack of correlation ( FIG, 1) is that the IPCC’s sensitivities are far too high and that the “Effective Radiative Forcing” for Long Wave GHGs is considerably lower than the “Effective Radiative Forcing “ for Short Wave solar.
APPENDIX 1
This experiment is attributed to Tallbloke and shows unequivocally that Long Wave radiation from GHGs has little or no effect on Ocean Heat Content. Short Wave Solar radiation, on the other hand, penetrates the oceans to a depth of ten meters or more and, therefore, adds significantly to OHC.
Konrad: Empirical test of ocean cooling and back radiation theory
Posted: August 25, 2011 by tallbloke in atmosphere, climate, Energy, Ocean dynamics
Some background –
Willis Eschenbach had a guest posting over at WUWT in which he claimed that LWIR could heat Earth’s oceans. Myself and several others on the thread contended that this LWIR was likely to be stopped by the evaporative skin layer and would not slow the exit of heat from the oceans. Numerous requests for empirical evidence to support Willis’s claim only resulted in one inapplicable study used by the “Hockey Team” to support such claims. After several hundred comments without empirical evidence being offered, I gave up reading and designed and conducted an empirical experiment that shows that any effect of backscattered LWIR on the cooling rate of water would be negligible.
What follows is an edited version of the experiment design and results as posted on the WUWT thread. I would encourage others to conduct similar experiments to check my results. The equipment required is not overly expensive and the results can be observed in minutes. The results appear to show the measurable difference between reflecting LWIR back to warm water when it is free to evaporatively cool and when it can only cool through conduction and radiation.
What is required –
– Two identical probe type digital thermometers with 0.1 degree resolution
– Two identical insulated water containers. I used rectangular 200ml Tupperware style containers, insulated on their base and sides with foil and Styrofoam. I cut away the clip on rim from each lid to create a frame to clip down cling film for Test B of the experiment.
– One IR reflector. I used an A4 sheet of 10mm Styrofoam with aluminium foil attached with spray adhesive.
– One IR window. I built an A4 size “picture frame” of 10mm square balsa wood strips and stretched cling film over it.
– One 1 litre measuring jug
– Two small identical computer fans. I used Suron 50mm centrifugal blowers powered by a 6v gel cell battery
– Extra cling film
– Optional extras – kitchen timer, an A4 ”dark cool sky” panel of matt black aluminium with peltier cooling, glamorous lab assistant of choice.
What to do –
– Position probe thermometers in identical positions in both water containers. I placed the tips 10mm below the water line by drilling force fit holes in the sides of the containers.
– Position IR reflector and IR window 50mm above either water container. You may need to build two Styrofoam side walls, but air must be free to move over the surface of the water. (The use of the IR window is to ensure that air flow is similar over each water container.)
– Position the computer fans to blow across the water surface of each container, but do not turn on.
– Fill jug with warm water, stir, then fill each water container from the bucket. I used water around 40C as the ceiling was around 18C not a 3k sky.
– When and equal amount of water is in each container, turn on the computer fans.
– Observe the temperature change over time for each tank. Less than half an hour is required for such a small amount of water. You should observe that both tanks cool a the same rate (TEST A).
– Now the important bit – Repeat the experiment, but this time lay a small sheet of cling wrap on the surface of the water in each water tank. This allows cooling through radiation and conduction but prevents evaporation. You do not need the computer fans on in this test. You should be able to observe that while both containers cool slower than before, water under the IR reflector cools slowest (TEST B).
Interpretation –
In TEST A the water cools more quickly, however the two water containers temperatures remain very close to each other over time. This indicates that backscattered LWIR has a very limited effect on the rate of cooling for water when it is free to evaporatively cool.
In TEST B both water containers cool more slowly than test A, but a divergence in temperature between the two water containers is readily detectable. The container under the foil sky cools more slowly than that under the cling wrap sky. This indicates that backscattered LWIR from a warm material can slow the rate at which that material cools, if radiation and conduction are the only methods for cooling.
Test A represents the evaporative cooling conditions in the real oceans. Test B represents how the climate scientists have modelled the oceans with regard to backscattered LWIR. From what I have observed, backscattered LWIR can slow the rate at which substances cool. However in the case of liquid water that is free to cool evaporatively this effect is dramatically reduced. It would appear that including the oceans in the percentage of Earth’s surface that could be affected by backscattered LWIR may be a serious error. Earth’s oceans cover 71% of the planets surface. If backscattered LWIR cannot measurably affect liquid water, then CO2 cannot cause dangerous or catastrophic global warming.
I have conducted further tests using a “cold sky” panel cooled with ice water over the top of the cling film IR window. While the temperature divergence in the evaporation restricted test B does not appear faster, it does appear to diverge for longer.
I would encourage others to conduct similar empirical experiments and share their observations. I would be interested in comments in further experimental design, or empirical evidence related to the LWIR question.
Typical TEST A
| Time | Cling Wrap Screen | Foil screen |
| 0 | 37.1 | 37.1 |
| 5 | 33.2 | 33.2 |
| 10 | 29.4 | 29.4 |
| 15 | 27 | 26.9 |
| 20 | 25.5 | 25.5 |
| 25 | 24.5 | 24.5 |
Typical TEST B
| Time | Cling Wrap Screen | Foil screen |
| 0 | 38.2 | 38.2 |
| 5 | 36.3 | 36.6 |
| 10 | 34.8 | 35.3 |
| 15 | 33.5 | 34.2 |
| 20 | 32.6 | 33.4 |
| 25 | 31.5 | 32.6 |
Regarding your point: I have attempted to mount a case for the idea that a given LONG WAVE GHG forcing will have considerably lower temperature response than a similar SHORT WAVE solar forcing.
If differential absorption at the planet’s surface is what you are trying to prove, then I have absolutely no interest.
The only way that the Earth’s surface can be 30 degrees Kelvin higher that it would be in the absence of GHG is if it absorbs and emits long wave radiation. The emittance of long wave radiation is close to unity. Absorbance and emittance must be identical, otherwise it would be possible to build a perpetural motion machine and violate the laws of thermodynamics.
If you had a piece of material that emitted, but did not absorb long wave radiation, it would cool spontaneously, and you could insert a thermocouple and get free electricity.
And if it is being asserted that emittance/absorbance is quite low, then how is the Earths natural temperature to be explained? There is not enough solar radiation to raise it to 290K odd.
Why has LIR GHG forcing increased over the last 60-70 years? You assume, wrongly, that GHG’s have increased over the past which is not true. Atmospheric CO2 content has varied from over 20% on the primordial planet to thousands ppmv millions of years ago. Measurements taken in Victorian times gives a CO2 content of up to 500ppmv. CO2 content varies diurnally, seasonally and with each hemisphere. Our measly input is but 3% of the total.
And #peterg there is more than enough radiation for 290K. Measured zenith radiation is ~1000W/m2, average hemispheric radiation 500W/m2 giving ~+34C average temperature before the heave losses which reduces it to ~+14C
April 22, 2013 at 1:17 am, I said:
“Yes, one can ‘show’ it theoretically using plain arithemtic and add the ‘back radiated’ flux from the absorptive gas layer to the sphere’s outgoing flux.”
The ‘outgoing flux’ should read ‘incoming flux’, i.e. the heat input from the sphere’s heat source.
I also said: “As you can see, the shell simply reduces the heat loss to space. It doesn’t heat its source, even when this is heated by its own source.”
I would change the ‘It doesn’t heat its source’ to ‘It doesn’t make the surface of the sphere (its heat source) warmer than what the sphere’s own heat source could manage on its own, neither by adding to its heat gain or subtracting from its heat loss’. It does reduce its heat loss, but that doesn’t mean it makes it warmer – check the links. This is where the confusion arises.
Lots of interesting comments here so far. As usual, understanding the basic physics concepts is vital to gaining an understanding of how things behave out in the real world. It would seem that this experiment is good for understanding one very important concept – what happens with LWIR w.r.t. water surfaces (Trenberth’s missing heat). The total details of what happens in the atmosphere and ocean surface cannot be duplicated on the lab bench. However, we can through various experiments deduce what happens.
As for what is happening overall, we have observations of the real system that can be combined with our experiments to help gain an understanding of what actually is going on and / or what is not going on.
First, a few little reminders of what the real system includes:
Earth is 70% ocean
Oceans have very low albedo, less than 0.04
Land has much higher albedo, averaging somewhere around 0.12 to 0.16
Sky with clouds provides most of our 0.3 albedo
Land is concentrated mostly in the Northern Hemisphere and oceans in the Southern Hemisphere
North and South Hemispheres are fairly close to each other in average temperature
More solar energy arrives to a hemisphere during the summer than the winter
Earth’s elliptical orbit provides significantly more power at aphelion (December) than at perihelion (June). Peak to peak difference at the TOA is about 90 W/m^2 out of about 1365 W/m^2.
What we see is that with rather little average temperature difference between hemispheres, we have substantially more solar energy arriving at the TOA along with a surface that will absorb significantly more energy in the Southern Hemisphere than in the Northern Hemisphere. This is not the case since the temperatures are not diverging. What we see is an incoming power difference many times the size of that added absorption achieved in a CO2 doubling.
What is happening is the water cycle. The added heat coming into the Southern Hemisphere goes into evaporating water at the surface of the ocean and then convects up to form clouds that shade the ocean from some of the incoming solar. This also increases the LWIR downwelling as there is added water vapor and the clouds absorb and emit LWIR as well. Moist air is ligher weight because the molecular weight of water is 18 versus the atmospheric average of 28.8 so it should be no surprise that it will rise conveying that excess heat up above must of the ghgs where it can radiate to space.
This expermiment presented is important in that it shows incoming LWIR energy evaporates water (which can then take it back up into the atmosphere for dispersal) rather than is absorbed, warming the lower ocean depth – per Trenberth’s imaginary missing heat.
NASA reports CO2 is a COOLANT in the atmosphere.
http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/
AGW theory says that human emissions of CO2 are causing global warming. There isn’t actually a lot of DIRECT evidence for that assertion per se. A lot of what people seem to think passes for evidence is little better than conjecture.
There. Fixed it for ya.
Watcher does not get it yet,
He is relying too much on “public” opinion
not realizing that that will change fast, once the global cooling sets in..
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
Richard111 is spot on.
How come Nasa knows all of this, and Hansen does not?
cba makes a lot of sense
I want to add something
I have a swimming pool here and an elaborate system to heat the water.
However, no matter how much energy I put in
the water will never get much above 32 here, no matter how much energy I put in.
All it does is evaporate faster when I try to make it hotter,
Does somebody know why this is so
(seeing that the oceans’ temps. don’t go much higher either…..)
and why this is important to what we are discussing here?
“All it does is evaporate faster when I try to make it hotter,
Does somebody know why this is so”
Atmospheric pressure sets the limits by fixing the energy cost for a given amount of evaporation at the sea/air interface.
Evaporation is a net cooling process so it is easy for it to put a limit on the maximum temperature that can be achieved at our ocean surfaces.
Then, since the energy capacity of the oceans is huge compared to that of air, it is but a trifle for the oceans to control air temperatures.
See here:
http://climaterealists.com/index.php?id=3735
“Our Saviour – The Hydrological Cycle by Stephen Wilde
Friday, July 17th 2009, 3:23 PM EDT “
Richard111 says:
April 22, 2013 at 7:07 am
NASA reports CO2 is a COOLANT in the atmosphere.
http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/
Yes as they say, “SABER monitors infrared emissions from Earth’s upper atmosphere”, above 100km! Also ““Carbon dioxide and nitric oxide are natural thermostats,” explains James Russell of Hampton University, SABER’s principal investigator. “When the upper atmosphere (or ‘thermosphere’) heats up, these molecules try as hard as they can to shed that heat back into space.”
“For the three day period, March 8th through 10th, the thermosphere absorbed 26 billion kWh of energy. Infrared radiation from CO2 and NO, the two most efficient coolants in the thermosphere, re-radiated 95% of that total back into space.”
HenryP says:
April 22, 2013 at 10:16 am
Richard111 is spot on.
How come Nasa knows all of this, and Hansen does not?
Hansen does and has done for a long time, unlike Richard111 who apparently didn’t read the post he referred to!
henry@Stephen Fisher
there are not too many of us who figured it out
it is the water cycle that keeps everything within limits
so that life can carry on
but the CO2 has little or nothing to do with it
i.e. with the temp. on earth
we do need more CO2 for life to thrive
i.e more crops, more lawn, more trees, etc…
don’t worry about Phil.
he never got anything from what I tried to tell him….
henry
Note to Anthony
Nnew facility ‘Rate This’ is open to misuse by deleting cookie, I just put up 5 ‘thumbs up’ on the previous comment, with apologies to Stephen Wild.
Note to Anthony
‘Rate This’ new facility is open to misuse, by deleting cookie, I just put up 5 ‘thumbs up’ on the previous comment, with apologies to Stephen Wild.
Then I put 5 ‘thumbs down’ on my post. With apology to the Anthony and mods.
I remain skeptical. The most important part of the experiment, viz. the glamorous lab assistant, is not shown in any of the illustrations.
This is also how Multi-layer insulation on spacecrafts works:
http://en.wikipedia.org/wiki/Multi-layer_insulation
“The principle behind MLI is radiation balance. To see why it works, start with a concrete example – imagine a square meter of a surface in outer space, at 300 K, with an emissivity of 1, facing away from the sun or other heat sources. From the Stefan-Boltzmann law, this surface will radiate 460 watts. Now imagine we place a thin (but opaque) layer 1 cm away from the plate, thermally insulated from it, and also with an emissivity of 1. This new layer will cool until it is radiating 230 watts from each side, at which point everything is in balance. The new layer receives 460 watts from the original plate. 230 watts is radiated back to the original plate, and 230 watts to space. The original surface still radiates 460 watts, but gets 230 back from the new layers, for a net loss of 230 watts. So overall, the radiation losses have been reduced by half by adding the additional layer. More layers can be added to reduce the loss further.”
Yes, but when I try to explain this simple model to the crazy dragonslayers as a reasonable model for a “colder object” heating a “warmer object” they seem incapable of understanding it.
This specific example is ALMOST a perfect (if oversimplified) model for greenhouse warming, if you switch from a constant temperature source to a constant power source. Suppose we have the same square meter of unit emissivity surface in outer space containing a heat source producing 460 watts, it will heat to 300K by the same argument you give above. If we surround it with a thin but opaque layer 1 cm away, separated from it by vacuum, and also of emissivity 1, it will be warmed by heat from the inner object until IT is losing power on its outer surface at a rate of 460 watts, because the system in steady state MUST lose 460 watts (the rate at which it is being heated). But if the opaque surface is radiating 460 watts outward, it is also radiating 460 watts inward. In order to be in detailed balance, the inner object has to be radiating 920 watts — 460 watts from its internal power supply, 460 watts it receives as “back radiation” from the surrounding opaque blackbody shell. To radiate 920 watts, it has to increase in temperature to 300 * (2^{1/4}) = 357 K. The outer shell will actually end up at a temperature slightly under 300 K (as it has a slightly larger surface area from which to lose 460 watts).
If you raise the shell so it is further away, you further increase its area and hence decrease its temperature when it is radiating 460 watts away, and also reduce the absorption cross-section of the object inside to the back radiation itself (some of which starts to travel from the opaque shell to the opaque shell without hitting the inner object at all). Overall this decreases the back radiation but leaves it strictly positive — the inner object will always heat up a bit (compared steady state 300K with no shell at all) as long as ANY back radiation is received from a surrounding shell. The Earth is a teeny, weeny bit warmer than it would be if it were steady heated and there were no 3K blackbody radiation from outer space, if outer space were perfectly dark and empty and hence had a “temperature” of 0K.
Voila! A cooler object (the shell, in steady state) causes a heated object to increase its temperature! And yet heat always flows from hot to cold, entropy increases, the gods of thermodynamics are pleased and shower one with rose petals.
The GHE in the atmosphere is complicated by the fact that it is only one of many things going on, and by the fact that to a large extent it is saturated in all bands associated with all the components of the atmosphere — opaque is opaque, and the logarithmic increase expected from increasing CO_2 concentration is almost an accidental result of (IIRC) pressure broadening of its particular quantum spectrum. So sure, differentially heating and cooling the atmosphere causes convection, conduction, latent heat transfer, and modulation of lots of other relevant stuff such as albedo and water that might well overwhelm any part of the GHE associated with increasing CO_2 BUT that does not mean that the mechanism itself is not valid or important in raising the mean temperature of the Earth compared to the atmosphere-free moon, only that most of the benefit we get from CO_2 was gotten by the first 100 ppm or so, and most of the total benefit (warming) we get now is from water vapor, not CO_2, by somewhere between one and two orders of magnitude.
At this point, since one can now see that there is nothing contradictory about an externally heated object becoming warmer when one interpolates an absorptive/emissive layer of gas between it and outer space at 3 K, one can actually look at the spectral data to try to understand it a bit better without trying to claim that it doesn’t exist at all. At which point I usually recommend that people buy a copy of Grant Petty’s book, because it has actual TOA and BOA spectrographs that are direct photographic evidence for the GHE — if you know how to read a spectrograph and mentally integrate over frequencies.
But kudos for finding the article above on multi-layer insulation. One can do even better, of course, if one has an surrounding layer that is truly reflective, has a high albedo on the inner surface. But atmospheric gases like CO_2 aren’t reflective in that sense; they really are opaque and diffusely absorptive (and re-emissive).
rgb
(Problem 27. As you can see, the shell simply reduces the heat loss to space. It doesn’t heat its source, even when this is heated by its own source. I quote: “A sphere of radius R is maintained at a surface temperature T by an internal heat source (Figure 3).” It doesn’t say ‘PLUS the back radiation from the surrounding shell.
Just in case you want to make this an issue, don’t misread this problem. The point is that the power source is variable and is adjusted to keep T constant so that the problem can be solved easily using the stuff in the chapter. However, it is just as easy to solve for constant power input into the sphere. In this case you will find that T of the inner sphere is a function of (among other things) the radius of the surrounding shell and (implicitly) its temperature.
I will also point out that when the outer shell is at radius e.g. 2R and not R+\Delta R for \Delta R << R, there is a nontrivial correction factor for the cross section of the inner sphere, given that thermal radiation is not given off only perpendicular to a small surface element of the curved inner surface of the shell. But as I also noted in the previous post, there will always be power GAIN from the back radiation and it will strictly raise the steady state temperature of the inner sphere.
rgb
The question that is the crux of much of this thread, is simply:- Does LWIR EM radiant energy that propagates downward from earth’s atmosphere, and cloud cover when present, HEAT (verb) the ocean; which implies that the ocean Temperature (whatever that means), is increased by the existence of such radiant energy ? Or does that not happen ?
Now it is well known (by observation) that in the Atlantic/Caribean waters, following the passage of a hurricane, and maybe lesser tropical storms, the surface waters in the track of the storm, are colder than before the storm passed through. Huge amounts of energy in the form of latent heat of evaporation, acompany the megatonnes of water that is in the cyclonic clouds of the storm. The ocean surface heat (noun) is the energy that powers the storm.
Not surprisingly, the high surface wind speeds rapidly remove water vapor from the reaction interface between ocean and atmosphere allowing further evaporation to occur. At the microscopic level, the H2O molecules with kinetic energies on the high energy tail of the Maxwell-Boltzmann energy distribution of the surface water molecules, are the ones that break free of the surface intermolecular forces, and escape from the surface. Chemical engineers know much better than I do, that removal of reaction products from the reaction interface, is essential to maintaining the process. Without removal, the increasing concentration of high energy molecules on the gaseous side of the reaction, results in increased flux of water molecules, back into the liquid phase, stopping the evaporation process. As a result, the liquid surface is depleted of higher energy molecules, resulting in a lower mean molecular kinetic energy. And the words we use to describe this are “lower Temperature”.
Evaporation naturally depresses the surface Temperature relative to the bulk of the liquid. Well that is simply the latent heat of evaporation.
As a result, there is a negative Temperature gradient at the surface, and this gradient, is the driving force causing conductive heat (noun) to flow from the bulk, towards the surface, to replace the latent heat of evaporation. If this did not happen, the evaporation must eventually cease.
So now consider what happens at this microscopic level, when we add in the downward LWIR EM radiant energy. Note I said “energy”. This is NOT heat (noun), it is radiation energy that knows nothing of Temperature, which is a macroscopic property of materials.
We know that this LWIR EM energy is very strongly absorbed in the top few microns of the surface; about 30 microns absorbs 95% of the 10 micron wavelength center of the atmospheric EM spectrum.
Absorption of this ENERGY is a microscopic process; it takes a molecule of water (or perhaps some molecular water complex) to absorb that LWIR photon; it is not a thermal (heat (verb) ) process.
But that absorbed quantum of energy will raise the kinetic energy of THAT WATER MOLECULE or complex, without raising the Temperature of the macroscopic body of water.
The kinetic energy bonus, that results in molecular escape (microscopic process) , can be supplied either by heat (noun) from the bulk of the water (macroscopic) or by the absorption of the LWIR photon, which is a microscopic process.
The negative Temperature gradient remains at the surface, and the surface is colder than the bulk; but evaporation rate is increased, because the downward EM radiation supplies the energy offset, to a single molecule or perhaps complex, to break that microscopia loose from the surface.
I can conceive of no process going on here, that results in heat (noun) propagating DOWNWARD from the surface, into the bulk of the ocean. The negative surface Temperature gradient maintains heat flow from the bulk to the surface, a macroscopic process, resulting in evaporation, and the microscopic process of adding photon energy to single molecules, accelerates the evaporative process. Note that the EM photon energy exits the surface along with the water molecule, and is returned to the atmosphere.
So I invite all comments showing me the error of my ways, and the glitch in my narrative ??
rgbatduke says, April 22, 2013 at 9:17 pm:
“Just in case you want to make this an issue, don’t misread this problem. The point is that the power source is variable and is adjusted to keep T constant so that the problem can be solved easily using the stuff in the chapter.”
Yes, that’s quite rich. Assume you’re right first and then interpret what the problem is actually saying afterwards. Good one. You can never be mistaken that way …
It doesn’t say anything about a variable heat source. That’s only your interpretation. Because in your mind that’s the only solution. That’s how it has to be. No, it simply states that the surface temperature of the inner sphere is maintained by its internal heat source … and nothing else. You didn’t read anything of the rest of the post? The example with the multi-layer insulation, exactly the same. You will of course again posit that the inner surface is somehow heated by a variable heat source even though no such premise is being laid out. Just to be right.
Show it rather than assert it.
Half the heat goes into warming the shell, the rest goes out to space. That’s it.
A black body in a vacuum at 290K emits 400 W/m^2. It does so no matter what. This flux is a function of its temperature. Based on heat gain from its heat source, a warmer body than itself. Its corresponding emission is dictated by the laws of physics.
If this body then receives a flux of 200 W/m^2 from another body adjacent to it at temperature 244K, then this flux will not be able to do anything in the way of increasing the level of thermal energy and thus the temperature of the 290K body. Its temperature is already set by its incoming flux from an even warmer body, say 6000K, its hot reservoir.
If you want to claim that the 290K body warms up to a higher steady-state temperature in the presence of the 244K body, then you are in effect saying that the 244K body operates as a second, independent heat source for the 290K body.
Why? Because nothing else has changed. The original heat source still sends but the 400 W/m^2 of 6000K spectrum radiation to the warm body. This will upon absorption in itself not warm it past the 290K it did before. The body also still emits its corresponding 400 W/m^2 flux of 290K spectrum radiation to its cold reservoir based on its temperature.
So if the temperature then still rises, then this must somehow be caused by something else. It must be caused by extra absorbed heat from somewhere. A positive transfer of (a gain in) thermal energy.
Well, the only other body in this system is the 244K one. The only thing that’s different is the 200 W/m^2 flux from the cool body to the warm.
You want to claim, I guess, that this radiative ‘counter-flux’ slows the cooling rate of the warm body, thus heating it indirectly. But how specifically does it accomplish this without itself transferring HEAT to it and thereby raising the warm body’s kinetic energy level beyond what it would be otherwise – and hence its temperature? Does it somehow disallow half of the 400 W/m^2 of 290K spectrum radiation from leaving the surface of the warm body?
Remember now, if the warm body is provided with a constant energy/heat supply from its ultimate heat source, it will not cool in the meaning ‘temperature dropping’. Its emission temperature is kept up, sustained. So the cool body can do nothing to reduce its ‘cooling rate’. There is no cooling rate to be reduced.
What is reduced is ‘the heat transfer rate’ between the warmer body and the cooler. Q. This does not affect the surface temperature of the warmer body. Only the surface temperature of the cooler one.
Temperature is set by absorbed heat.
Sorry Bob most of your argument fails as most comments have already highlighted. There is a problem with the IPCC projections and it’s much more basic it’s not the understanding of greenhouse effect. The physics of the greenhouse effect is well understood and outside the ability of climate science or pseudoscience types on here to challenge because it falls into the Quantum Mechanics field the classic physics approximations used by the IPCC are reasonable at the level they use.
So now as a scientist looking at the whole stupidity of climate change from the outside there is an obvious problem of the AGW IPCC disaster scenario
Start with wiki on http://en.wikipedia.org/wiki/Radiative_forcing and go to the climate sensitivity section first we get the IPCC calculation:
A typical value of λ is 0.8 K/(W/m2), which gives a warming of 3K for doubling of CO2.
Now move down the page to the next section “Forcing due to atmospheric gas”
The relationship between carbon dioxide and radiative forcing is logarithmic, and thus increased concentrations have a progressively smaller warming effect.
Two views of the same equation expressed a different way both saying the same thing you need a logarithmical increase in CO2 production to support a linear temperature rise.
Now go look at the CO2 figures for the atmosphere and then look at the IPCC CO2 projections
http://www.ipcc-data.org/ddc_co2.html
See the problem only the A2 and A1F1 scenarios give you an exponential CO2 levels and they both look impossible scenarios based on the amount of fossil fuels you would have to burn and the growth of fossil fuels is not following that projection
http://en.wikipedia.org/wiki/World_energy_consumption
The last 15 years of climate slowdown is because the CO2 levels are not exponentially increasing the rate will continue to slow from the early prior based on the IPCC’s own figures and science.
Looking at the numbers CO2 will be at 550-650ppm by 2100 so 1.5 degree K warmer than now based on the science.
My problem is this suddenly becomes 4 degree C in the IPCC release.
Look at the US EPA page for example
http://www.epa.gov/climatechange/science/future.html
Look at the graph of CO2 only the two much higher emission scenarios project the levels of CO2 to the required 800 ppm CO2 levels to get a 3 degree K rise.
The problem isn’t the science its the politics because the real thing climate science needs to show is that we are following a A1F1 and A2 scenario because that’s the only ones that put 4 degree C rise as even a possibility and the disaster scenarios.
The problem for climate science is the developed countries have leveled there fossil fuel consumption and only the big developing nations like China, India and Brazil are increasing there emissions and it is not at a logarithmic rate and they have to do better than natural log 2 rate to make up for the rest of the world that is relatively flat. China and India increased C02 by 9% and 6%, respectively, in 2011 but this lead to a modest increase in emissions for the world of 3%.
Hence emission scenarios A1F1 and A2 fall based on economic data and common sense that CO2 emission can not and are not following a logarithmic rate.
This is sort of an extension of the same stupidity Anthony took Joe Romm to task on about a 6 degree F rise by 2050 which would require CO2 levels to be 800ppm by that time. If you go an look at the CO2 graphs you will see we have moved the CO2 levels from 310 in the sixties to 400ppm now so around 90 ppm. Think about how much fossil fuel you are going to burn to lift it a further 400 ppm and tell me do you really think that can be done in 35 year time frame?
“george e. smith says:
April 22, 2013 at 9:36 pm”
That is pretty much how I see it too.
Additional evaporation will always remove all the energy that provokes that evaporation because evaporation is a net cooling process.
@Richard111
Your link (http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/) comes from a hard sciences unit where we don’t care about the stupidity arguments the pseudoscience in climate change argue about.
You can’t energy pump the atmosphere without it reacting because it is has an equilibrium loop the sort the pseudoscience types want to emit to justify their view on why AGW does or does not exist depending on there political view.
Real scientists actually realize the atmosphere can cool or heat depending on the energy balance but that has little to do with climate change where you assume the suns intensity is relatively constant over time and therefore the equilibrium loops should hold the temperature stable.
AGW is saying you are changing the gas mixture in that exact loop that the scientist in the report measured and therefore the temperature of earth is changing. No physicist ever said CO2 only heats it is simply acts like all quantum active gas in the atmosphere in it’s energy pump loop.
There is something unique about all the Greenhouse gases you can build lasers from them because it utilizes the same quantum energy pumping effect
Nitrous oxide lasers operate in far infrared typically 10.8 μm wavelength
CO2 lasers operate in the far infrared range typically 9.6 µm and 10.6 µm
Water vapour lasers operate in the infrared typically 27.97, 47.7, 78.46, and 118.6 µm
For me coming from a QM science background I find it sort of funny when you get people try and claim they can prove using some classic physics garbage they dream up that the greenhouse effect doesn’t exist …. sure it doesn’t and my laser tubes don’t work either according to your classic physics you just mashed up.
There may be problems with the IPCC science like feedbacks and UHI like Anthony has written on but I am sorry to the pseudoscience fringe the greenhouse effect is real and well beyond the scope of climate science stupidity to overturn the science on.
rgbatduke says, April 22, 2013 at 9:00 pm:
“This specific example is ALMOST a perfect (if oversimplified) model for greenhouse warming, if you switch from a constant temperature source to a constant power source. Suppose we have the same square meter of unit emissivity surface in outer space containing a heat source producing 460 watts, it will heat to 300K by the same argument you give above. If we surround it with a thin but opaque layer 1 cm away, separated from it by vacuum, and also of emissivity 1, it will be warmed by heat from the inner object until IT is losing power on its outer surface at a rate of 460 watts, because the system in steady state MUST lose 460 watts (the rate at which it is being heated). But if the opaque surface is radiating 460 watts outward, it is also radiating 460 watts inward. In order to be in detailed balance, the inner object has to be radiating 920 watts — 460 watts from its internal power supply, 460 watts it receives as “back radiation” from the surrounding opaque blackbody shell. To radiate 920 watts, it has to increase in temperature to 300 * (2^{1/4}) = 357 K. The outer shell will actually end up at a temperature slightly under 300 K (as it has a slightly larger surface area from which to lose 460 watts).”
I didn’t see this until now. Er, rgb, you got this exactly wrong. It says it is 300K radiating 460 W/m^2 both before AND after you put the opaque layer outside it. What the insulating layer does is reducing the heat loss to space, not the heat loss from the inner layer, the heat source of the outer (opaque) layer.
Notice what it says: “The principle behind MLI is radiation balance.” There IS radiative balance when the inner plate radiates 460 W/m^2 to the opaque layer, keeping it at a temperature of 252K (230 W/m^2 going out from each side). Reread the quote:
“(…) imagine we place a thin (but opaque) layer 1 cm away from the plate, thermally insulated from it, and also with an emissivity of 1. This new layer will cool until it is radiating 230 watts from each side, at which point everything is in balance. The new layer receives 460 watts from the original plate. 230 watts is radiated back to the original plate, and 230 watts to space. The original surface still radiates 460 watts, but gets 230 back from the new layer, for a net loss of 230 watts. So overall, the radiation losses have been reduced by half by adding the additional layer.”
Why do you think the opaque layer cools until it’s radiating 230 watts from each side? Because it receives a constant flux of 460 watts from the inner plate. Because it starts out at some temperature but has no heat source of its own so will equilibrate with its newfound one (the plate). This dynamic equilibrium is achieved at the point where the constant flux of 460 W/m^2 from the plate is balanced by the opaque layer’s emission – temperature 252K, radiative flux 230 W/m^2 outwards and inwards.
Also, look at this problem from another physics textbook:
http://i341.photobucket.com/albums/o396/maxarutaru/bunnytaru/lol%20censorship/heatsourceinshellatequilibrium_zps1c9d662a.png
Why do you think they don’t seem to concern themselves at all about the purportedly necessary change in the black sphere’s temperature T when the shell is emplaced? That would be a relevant point to delve into, no? All they’re asking for is how the temperature of the shell will relate to T and also how this radiative equilibrium temperature will affect the total power radiated to the surroundings? If R ~ r, then the shell (if considered fully absorptive) will be ~19% cooler than the sphere. It doesn’t say anything about the shell necessarily having to get 19% warmer than before in order to be able to maintain the shell’s temperature. Note (b) where the black sphere and the heat shield is likened to a star with a surrounding dust cloud. A star is pretty constantly heated, wouldn’t you say so?
A final request:
rgb, could you direct me to a controlled real-world experiment conducted in a vacuum chamber where the surface of a central sphere, internally and constantly heated, reaches a new steady state temperature at a minimum of 19% (R ~ r) warmer than the old one, when a shell is placed around it, enclosing it? Well, maybe 19% is a little bit too much to ask for, but at least way beyond any margins of error.
You see, I don’t think I’ve ever heard of any such results being presented at any time during these discussions. But I guess that doesn’t mean they don’t exist …
henry@all here who are confused by the remarks by LdB
perhaps LdB should also first read what the argument was about:
http://wattsupwiththat.com/2013/04/21/efficacy-of-green-house-gas-forcing-compared-to-solar-forcing/#comment-1283346
this argument has nothing to do with politics…..
we were arguing science….
we were in fact asking those who claim to know, to show us that the net effect of more carbondioxide in the air is that of warming, rather than that of cooling.
Richard111 merely pointed to a fact that what we already knew, namely that (more) CO2 also acts as (more of) a coolant…..
Perhaps as a chemist, I should try to explain a point that may be confusing to some.
We know that water has strong absorbency in the UV. The oceans also have lots of mass, so as the UV from the sun hits on the water, that specific radiation where water has absorbency, is easily converted to heat.
However, a gas has little mass. A GHG is gas that has (some) absorbency both in the sun’s emission spectrum and in the earth’s emission spectrum. CO2 is a GHG. As the sun’s radiation falls on the molecule, it can absorb in the absorptive regions only until it itself is saturated (with heat). Remember also that most of the neighbor molecules (N2, O2,) are transparent to the absorptive regions anyway, so it is not possible for the molecule to pass that radiation specific to the absorptive regions on as heat as happened in the water. So all it can do is re-radiate here. To try to understand what happens up there, it is perhaps simpler to imagine that in the absorptive regions, the molecule starts acting like a little round mirror as soon as it is saturated by that specific radiation. That still means that approx. 50% of incoming radiation in the absorptive regions is sent in a radius of 180 degrees back in the the direction where it came from. Hence we are able to measure even as it comes back from the moon.
http://www.iop.org/EJ/article/0004-637X/644/1/551/64090.web.pdf?request-id=76e1a830-4451-4c80-aa58-4728c1d646ec
For example, they measured this re-radiation from CO2 as it bounced back to earth from the moon. So the direction was sun-earth (day)-moon(unlit by sun) -earth (night). Follow the green line in fig. 6, bottom. Note that it already starts at 1.2 um, then one peak at 1.4 um, then various peaks at 1.6 um and 3 big peaks at 2 um. You can see that it all comes back to us via the moon in fig. 6 top & fig. 7. Note that even methane cools the atmosphere by re-radiating in the 2.2 to 2.4 um range.
This paper here shows that there is absorption of CO2 at between 0.21 and 0.19 um (close to 202 nm):
http://www.nat.vu.nl/en/sec/atom/Publications/pdf/DUV-CO2.pdf
There are other papers that I can look for again that will show that there are also absorptions of CO2 at between 0.18 and 0.135 um and between 0.125 and 0.12 um.
We already know from the normal IR spectra that CO2 has big absorption between 4 and 5 um.
So, to sum it up, we know that CO2 has absorption in the 14-16 um range causing some warming (by re-radiating earthshine) but as shown and proved above it also has a number of absorptions in the 0-5 um range causing cooling (by re-radiating sunshine). This cooling happens at all levels where the sunshine hits on the carbon dioxide same as the earthshine. The way from the bottom to the top is the same as from top to the bottom. So, my question is: how much cooling and how much warming is caused by the CO2? How was the experiment done to determine this and where are the test results?
From all of this, you should have figured out by now that any study implying that the net effect of more CO2 in the atmosphere is that of warming, rather than that of cooling, must exhibit a balance sheet in the right dimensions showing us exactly how much radiative warming and how much radiative cooling is caused by an increase of 0.01% of CO2 that occurred in the past 50 years in the atmosphere. It must also tell us the amount of cooling caused by the increase in photosynthesis that has occurred during the past 50 years. (plants need warmth and CO2, you know)
There are no such results in any study, let alone in the right dimensions. For example, consider the fact that time must be in the dimensions.
For more on why it is considered highly unlikely that CO2 is a contributory cause to global warming, see here:
http://blogs.24.com/henryp/2013/02/21/henrys-pool-tables-on-global-warmingcooling/
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
The above results suggest that a natural cooling cycle started around 1995.
We will stay in that cooling loop until ca. 2040.
Believe me, global warming is over. It is not only me who says it.
http://www.woodfortrees.org/plot/hadcrut4gl/from:2002/to:2013/plot/hadcrut4gl/from:2002/to:2013/trend/plot/hadcrut3vgl/from:2002/to:2013/plot/hadcrut3vgl/from:2002/to:2013/trend/plot/rss/from:2002/to:2013/plot/rss/from:2002/to:2013/trend/plot/gistemp/from:2002/to:2013/plot/gistemp/from:2002/to:2013/trend/plot/hadsst2gl/from:2002/to:2013/plot/hadsst2gl/from:2002/to:2013/trend
Kristian says:
April 22, 2013 at 10:02 pm
I think you are continuing the mistake of equating energy with time rate of change of energy. I’m not entirely sure, because your posts are turgid and meandering, and try as I might, I cannot seem to find a point.
The time rate of change of energy does not have to balance instantaneously. Energy will accumulate over any time interval in which the rate of change is not balanced. Watts is not heat. Heat is energy. Watts is a unit of the time rate of change of energy.
Now, with that as an initial given, please succinctly state your position: Are you saying that an opaque shell about a body with internal heat source will or will not increase the surface temperature of the body?
LdB says:
April 22, 2013 at 11:31 pm
“…you need a [exponential] increase in CO2 production to support a linear temperature rise.”
The increase in CO2 concentration is not exponential, it has been approximately quadratic, and for the past 15 or so years, has essentially been linear, as the rate of change has leveled off coincident with the leveling off of temperatures.
The derivative of an exponential is an exponential, which is a convex function. In the plot at the first link I just gave, you can clearly see that the derivative here is concave.