Guest post by Ira Glickstein
The Atmospheric “greenhouse effect” has been analogized to a blanket that insulates the Sun-warmed Earth and slows the rate of heat transmission, thus increasing mean temperatures above what they would be absent “greenhouse gases” (GHGs). Perhaps a better analogy would be an electric blanket that, in addition to its insulating properties, also emits thermal radiation both down and up. A real greenhouse primarily restricts heat escape by preventing convection while the “greenhouse effect” heats the Earth because GHGs absorb outgoing radiative energy and re-emit some of it back towards Earth.
Many thanks to Dave Springer and Jim Folkerts who, in comments to my previous posting Atmospheric Windows, provided links to emission graphs and a textbook “A First Course in Atmospheric Radiation” by Grant Petty, Sundog Publishing Company.
Description of graphic (from bottom to top):
Earth Surface: Warmed by shortwave (~1/2μ) radiation from the Sun, the surface emits upward radiation in the ~7μ, ~10μ, and ~15μ regions of the longwave band. This radiation approximates a smooth “blackbody” curve that peaks at the wavelength corresponding to the surface temperature.
Bottom of the Atmosphere: On its way out to Space, the radiation encounters the Atmosphere, in particular the GHGs, which absorb and re-emit radiation in the ~7μ and ~15μ regions in all directions. Most of the ~10μ radiation is allowed to pass through.
The lower violet/purple curve (adapted from figure 8.1 in Petty and based on measurements from the Tropical Pacific looking UP) indicates how the bottom of the Atmosphere re-emits selected portions back down towards the surface of the Earth. The dashed line represents a “blackbody” curve characteristic of 300ºK (equivalent to 27ºC or 80ºF). Note how the ~7μ and ~15μ regions approximate that curve, while much of the ~10μ region is not re-emitted downward.
“Greenhouse Gases”: The reason for the shape of the downwelling radiation curve is clear when we look at the absorption spectra for the most important GHGs: H2O, H2O, H2O, … H2O, and CO2. (I’ve included multiple H2O’s because water vapor, particularly in the tropical latitudes, is many times more prevalent than carbon dioxide.)
Note that H2O absorbs at up to 100% in the ~7μ region. H2O also absorbs strongly in the ~15μ region, particularly above 20μ, where it reaches 100%. CO2 absorbs at up to 100% in the ~15μ region.
Neither H2O nor CO2 absorb strongly in the ~10μ region.
Since gases tend to re-emit most strongly at the same wavelength region where they absorb, the ~7μ and ~15μ are well-represented, while the ~10μ region is weaker.
Top of the Atmosphere: The upper violet/purple curve (adapted from figure 6.6 in Petty and based on satellite measurements from the Tropical Pacific looking DOWN) indicates how the top of the Atmosphere passes certain portions of radiation from the surface of the Earth out to Space and re-emits selected portions up towards Space. The dashed line represents a “blackbody” curve characteristic of 300ºK. Note that much of the ~10μ region approximates a 295ºK curve while the ~7μ region approximates a cooler 260ºK curve. The ~15μ region is more complicated. Part of it, from about 17μ and up approximates a 260ºK or 270ºK curve, but the region from about 14μ to 17μ has had quite a big bite taken out of it. Note how this bite corresponds roughly with the CO2 absorption spectrum.
What Does This All Mean in Plain Language?
Well, if a piece of blueberry pie has gone missing, and little Johnny has blueberry juice dripping from his mouth and chin, and that is pretty good circumstantial evidence of who took it.
Clearly, the GHGs in the Atmosphere are responsible. H2O has taken its toll in the ~7μ and ~15μ regions, while CO2 has taken its bite in its special part of the ~15μ region. Radiation in the ~10μ region has taken a pretty-much free pass through the Atmosphere.
The top of the Atmosphere curve is mostly due to the lapse rate, where higher levels of the Atmosphere tend to be cooler. The ~10μ region is warmer because it is a view of the surface radiation of the Earth through an almost transparent window. The ~7μ and 15μ regions are cooler because they are radiated from closer to the top of the Atmosphere. The CO2 bite portion of the curve is still cooler because CO2 tends to be better represented at higher altitudes than H2O which is more prevalent towards the bottom.
That is a good explanation, as far as it goes. However, it seems there is something else going on. The ~7μ and ~15μ radiation emitted from the bottom of the Atmosphere is absorbed by the Earth, further warming it, and the Earth, approximating a “blackbody”, re-emits them at a variety of wavelengths, including ~10μ. This additional ~10μ radiation gets a nearly free pass through the Atmosphere and heads out towards Space, which explains why it is better represented in the top of the Atmosphere curve. In addition, some of the radiation due to collisions of energized H2O and CO2 molecules with each other and the N2 (nitrogen), O2 (oxygen) and trace gases, may produce radiation in the ~10μ region which similarly makes its way out to Space without being re-absorbed.
There is less ~15μ radiation emitted from the top of the Atmosphere than entered it from the bottom because some of the ~15μ radiation is transformed into ~10μ radiation during the process of absorption and re-emission by GHGs in the atmosphere and longwave radiation absorbed and re-emitted by the surface of the Earth.
Source Material
My graphic is adapted from two curves from Petty. For clearer presentation, I smoothed them and flipped them horizontally, so wavelength would increase from left to right, as in the diagrams in my previous topics in this series. (Physical Analogy and Atmospheric Windows.)
Here they are in their original form, where the inverse of wavelength (called “wavenumber”) increases from left to right.
Source for the upper section of my graphic.
Top of the Atmosphere from Satellite Over Tropical Pacific.
[Caption from Petty: Fig. 6.6: Example of an actual infrared emission spectrum observed by the Nimbus 4 satellite over a point in the tropical Pacific Ocean. Dashed curves represent blackbody radiances at the indicated temperatures in Kelvin. (IRIS data courtesy of the Goddard EOS Distributed Active Archive Center (DAAC) and instrument team leader Dr. Rudolf A. Hanel.)]
Source for the lower section of my graphic.
Bottom of the Atmosphere from Surface of Tropical Pacific (and, lower curve, from Alaska).
[Caption from Petty: Fig. 8.1 Two examples of measured atmospheric emission spectra as seen from ground level looking up. Planck function curves corresponding to the approximate surface temperature in each case are superimposed (dashed lines). (Data courtesy of Robert Knutson, Space Science and Engineering Center, University of Wisconsin-Madison.)]
The figures originally cited by Dave Springer and Tim Folkerts are based on measurements taken in the Arctic, where there is far less water vapor in the Atmosphere.
[Fig. 8.2 from Petty] (a) Top of the Atmosphere from 20km and (b) Bottom of the Atmosphere from surface in the Arctic. Note that this is similar to the Tropical Pacific, at temperatures that are about 30ºK to 40ºK cooler. The CO2 bite is more well-defined. Also, the bite in the 9.5μ to 10μ area is more apparent. That bite is due to O2 and O3 absorption spectra.
Concluding Comments
This and my previous two postings in this series Physical Analogy and Atmospheric Windows address ONLY the radiative exchange of energy. Other aspects that control the temperature range at the surface of the Earth are at least as important and they include convection (winds, storms, etc.) and precipitation (clouds, rain, snow, etc.) that transfer a great deal of energy from the surface to the higher levels of the Atmosphere.
For those who may have missed my previous posting, here is my Sunlight Energy In = Thermal Energy Out animated graphic that depicts the Atmospheric “greenhouse effect” process in a simlified form.
I plan to do a subsequent posting that looks into the violet and blue boxes in the above graphic and provides insight into the process the photons and molecules go through.
I am sure WUWT readers will find issues with my Emissions Spectra description and graphics. I encourage each of you to make comments, all of which I will read, and some to which I will respond, most likely learning a great deal from you in the process. However, please consider that the main point of this posting, like the previous ones in this series, is to give insight to those WUWT readers, who, like Einstein (and me :^) need a graphic visual before they understand and really accept any mathematical abstraction.
As I have said before there is no need to agree with the AGWarmists’ basic argument, which is that AGW is real, in an attempt to win over the harts and minds of the public. That is no way to convince anyone that your message is the right one. Once it becomes known that that is the way you convey your scientific messages; ‘Your scientific standing is soon lost.’
Why don’t you instead put the “Global Energy flow Chart” by Kiehl and Trenberth (1997) on the desk in front of you and study it. – Study it well, and you should have no problem at all in dissecting it and then expose it as some kind of juvenile science fiction which has no place among grown ups
Kiehl and Trenberths’ (1997) energy flow plan does depict the ’greenhouse gases’ as forming a blanket high up in the Troposphere. You do mention this blanket yourself. And Trenberth shows us where it is.
Below is a bit of help to get you going as I cannot send/post the plan itself, however bear in mind that Kirchhoff’s Law is based on the conservation of energy prinsiple and logically therefore a body cannot emit more energy than it receives or absorbs. And also bear in mind the Law of Thermodynamics which says that energy can neither be created nor destroyed.
The plan has an average incoming solar energy amounting to 342 W/m² (or ¼ of “The Solar Constant”) – The proportion of energy, that is initially emitted by the Sun, is partly absorbed by the atmosphere: 67 W/m² + partly by the Surface: 168 W/m² – and to account for all the 342 W/m² there are 107 W/m² which are reflected straight back to space both from clouds and surface which therefore can be ignored, for now at least. (These numbers may vary in other later revised plans but this is the original and the numbers do not really matter as long as energy in equals energy out, which is what, of course they do here: 67 incoming W/m² are directly absorbed by the atmosphere +168 W/m² directly by the surface = 235W/m² emitted into the Earth’s system. From the surface, energy transfer to the atmosphere is as follows; 24 W/m² by thermals and 78 W/m² in the form of evapo-transpiration + 66 W/m² (from the subsequent 390 W/m² total surface radiation) This makes energy escape from surface 168 W/m² and we have surface equilibrium.
However these 66 W/m² constitute, in my opinion, a mistake as there is an atmospheric window involved that sends 40 W/m² straight – or unhindered by GHGs, back into space. – As all radiation in the form of back radiation from GHGs must logically be at wave-lengths that all can and will be re-absorbed by GHGs, all of those 40 W/m² must thus be from what the surface converts from solar irradiation. Therefore only 26 W/m² and not the full 66 W/m² should pass on into the atmospheric GHGs for absorption & subsequent back radiation. In any case, – think about it, – but in the meantime let’s get back to the plan which ends up showing that all of the 168 W/m² absorbed by the surface + what has been directly absorbed by the atmosphere is in the end emitted back into space as 235 W/m². And we have complete equilibrium.
If we are to assume thermal equilibrium, the regular features, excluding the greenhouse cycle, all tally up: 342 W/m² incoming solar energy is balanced by 107 W/m² (reflection) + 235 W/m² (emission) = 342 W/m² outgoing radiation. However as the total surface absorption of 168 W/m² can only be balanced by 24 W/m² (thermals) + 78 W/m² evapo-transpiration + 66 W/m² = 168 W/m² emitted by the surface things get a bit mysterious from here on in as Kiehl and Trenberth (1997) go on to supply the surface with an additional 324 W/m² of magical radiation from “GHGs”. I say magical because in this case the surface absorbs all of this radiation instead of reflecting one single Watt (If it did, that would mean that the Earth system gives off more energy than it receives). My question however is still what it has always been: Where do the GHGs get the energy to emit 324 W/m² in the first place? Even if we imagine that this back radiation takes place before equilibrium is reached and the 235 W/m² has not yet been re-emitted back to space 235 W/m² is all we have to play with once the 107 W/m² have been reflected.
But that’s not all that is magical, The 324 W/m² are all directed towards the surface!!
But we know, don’t we, that radiation is emitted in straight lines in all directions from it’s source? So that must mean that at least (324 + 107 + 235) W/m² is emitted /reflected away from the “Earth System” while only 342W/m² are coming in.
Somebody is making a mistake somewhere.
– But that is not all the magic, no- no, oh-no, on its way towards the surface or space, back-radiation from GHGs never encounters other GHGs which absorbs that radiation and thus are warmed by it. It only happens at the surface.–
I realise that my writings may be a bit hard to follow unless you have the Energy Flow Plan at hand, but are Kiehl and Trenberth really worth defending Ira?
It is very likely you will create energy sooner rather than later if you do.
to Phil
There is a great difference between you and I. I have spent over 20 years designing and testing thermal radiation sensors and temperature sensors out in the field.
You, I suspect, have no such experience whatsoever with any of that sort of thing.
I am very much aware of the convective component.
But, the central Antarctic is the most unique location in the entire world for one simple reason, which you obviously are unaware of.
It is the coldest.
Think about that for a moment.
The reason the temperature from the central Antarctic is so pristine is because of that.
And that is the reason the temperature data from central Antarctic is so important.
There is NOTHING on earth that can drive DOWN those temperature readings, EXCEPT radiational heat transfer AND/OR a lessening of the quantity of heat energy in the atmosphere, hence affecting convection. Period.
It makes NO difference which component it is, radiation or convection.
The LOW temperatures recorded there are the most accurate data representing the heat content TREND of the components of the atmosphere, REGARDLESS OF THE MECHANISM.
The key is to track the LOWS in Antarctica. That’s all that is needed. When you do that, the trend is flat to DOWN for Amundsen-Scott and Vostok from 1957 to date.
The REST of the earth, including the ARCTIC, there are plenty of mechanisms that can locally drive the temperatures both UP and DOWN. Localized effects. And you can chase those to your hearts content, and from now until forever, and you will never get anywhere because of the complexity of the system and the huge error bars of the temperature data methods used. It’s all noise.
And there are lots of things, noise, ON earth that can drive the temperature temporarily UP in the Antarctic.
But there is NOTHING on earth that can drive them DOWN.
That is clean data. ‘Signal to noise ratio’ is highest in the Antarctic, of all the locations on the planet. You only have to realize which part of the signal to pay attention to and which part to ignore.
Think it through.
It’s not so hard to understand if you learn to think for yourself a little.
Sorry, minor mistake.
My previous post should have been:
to Joel Shore
not Phil. My apologies to Phil.
Domenic says:
March 13, 2011 at 7:39 pm
“But there is NOTHING on earth that can drive them DOWN.”
Au contaire. Just off the top of my head the antarctic polar vortex strength can lower atmospheric pressure at the surface which causes the atmosphere to cool by expansion and it can also suck cold air from the stratosphere down to the surface. The PV is persistent in the winter but varies in strength and has not been very well observed for long. No one really knows how much mixing there is across it or at what altitudes any air exchange takes place. Also off the top of my the ozone hole is variable and is known to play a role in stratospheric temperature and if everything else is equal when the stratosphere warms the troposphere cools. Aerosols are also variable as are high altitude clouds. Any of these factors can drive temperatures down or up. The antarctic may have the least in the way of confounding factors but it still doesn’t exist in a black vacuum like the perpetually shaded interior of a crater on the moon.
http://www.cfm.brown.edu/people/sean/Vortex/
http://www.theozonehole.com/climate.htm
Domenic, kforestcat, bryan, smokey, et al
You’re debating with Joel Shore? Scroll back to his first comment in this thread where he “highly recommends” a specific text by a specific author which he finds challenging. When criticized for finding it challenging if he indeed teaches at the level he claims he does, he responds to advise that he’s only up to chapter 3.
Given that by his own admission he’s barely past the introduction, and yapping at people that they clearly don’t understand certain things and they should read some science for themselves from a text that he “highly recommends”…but hasn’t actually read… admits he doesn’t understand…
’nuff said.
CO2 absorbs a portion of upwelling energy from the earth’s surface. Absent CO2 this energy would have proceeded at the speed of light from surface to space. After CO2 absorbs this radiation it transfers it by conduction, not radiation, to surrounding molecules. Energy transfer via conduction doesn’t proceed at the speed of light. In effect this slows down the rate at which energy from the surface can escape to space. The slower rate causes the surface temperature to drop more slowly than it otherwise would at night. When the sun comes along to heat the surface the next day the surface starts from a point a little less cold and thus gets a little warmer during the day than it otherwise would. When the sun goes down the less cool starting temperature allows heat to escape faster than it otherwise would. At some point the less cool surface temperature speeds up the rate of energy loss to exactly balance the slowdown caused by CO2 and a new equilibrium temperature is born.
For the confused I took some pains to never say the surface heats up but rather used the awkward term “less cool”. It’s really awkward but it’s got to point where the crys of “cooler objects can’t heat warmer objects” is more annoying than it is awkward to phrase it differently.
>>
O H Dahlsveen says:
March 13, 2011 at 7:25 pm
Somebody is making a mistake somewhere.
<<
There are problems with Kiehl and Trenberth 1997, but the points you raised aren’t the ones. The 66 W/m² is the net flow from the surface or 390 W/m² – 324 W/m² = 66 W/m². You can’t subtract the 40 W/m² from the 66 W/m² because the amount escaping through the atmospheric window comes from the total surface radiation of 390 W/m² or 390 W/m² – 40 W/m² = 350 W/m². Therefore, the total radiation that the atmosphere receives is that 67 W/m² from the Sun, the 24 W/m² sensible heat flux, the 78 W/m² latent heat flux, and the 350 W/m^2 remainder from the surface or 67 W/m² + 24 W/m² + 78 W/m² + 350 W/m² = 519 W/m². Of the 519 W/m², 324 W/m² radiates back to the surface and the remaining 519 W/m² – 324 W/m² = 195 W/m² radiates to space. Add that to the 40 W/m² escaping through the atmospheric window, and it adds to 235 W/m². That’s the same value as the solar input or 168 W/m² + 67 W/m² = 235 W/m².
I’ve created a model that runs KT 97, and it stabilizes at those numbers just fine.
Jim
@DavidHoffer
“The photon carries energy. It has a mass of zero.”
It has a rest mass of zero. It is never at rest thus it always has mass.
“It gets absorbed by a piece of matter. Since this changes the mass of the matter by zero”
No, it actually does increase the mass by an infinitesimal but non-zero amount. You can calculate the increase by the equivalency E=MC^2.
“but increases the amount of energy by what the photon was carrying, it now contains more energy than if the photon had not been absorbed.”
I’d have to think about that a bit. Photons can increase or decrease the momentum of matter which is the same as saying it can increase or decrease its temperature.
Bose-Einstein condensates are typically formed by laser cooling. A stream of atoms is sent upstream into a laser beam. The photonic and atomic moments are in opposition and cancel out. The atoms slow down which is the same thing as getting colder. Temperatures very close to absolute zero are thus obtained. The energy lost from the atom has to go somewhere though so I reckon the atoms in question are absorbing a photon of one frequency hitting them in the face and spitting a photon out their rear end that’s higher frequency. I could be wrong about that as all I really know for sure is that energy books have to balance at the end of the day and I can’t think of any other way to balance them.
Light sails work in the same manner only in that case the moments are additive. However a light sail has to be a mirrored surface otherwise it gets hotter instead of moving faster. I once asked a physicist what sort of change happens to the photon when it bounces off the light sail. Since energy must be conserved the momentum imparted to the sail must mean energy is lost from the photon. Since the photon by definition can’t slow down and must necessarily lose energy he gave me the only possible answer I could think of – the reflected photon is of a lower wavelength.
Anyhow, given the usual physical correctness of your comments I’m surprised hear you say that a photon has no mass and its energy doesn’t increase the mass of something which absorbs it. It may be a miniscule increase but it isn’t non-zero.
Dave Springer says:
……”CO2 absorbs a portion of upwelling energy from the earth’s surface. Absent CO2 this energy would have proceeded at the speed of light from surface to space.”…..
CO2 has a significant absorption wavelength around 4um
Absence of IR active CO2 would lead to more Solar Radiation reaching Earth Surface =>Higher surface temperatures.
H2O is a significant absorber in the 15um area so CO2 not absorbing here would be filled in with H2O activity.
As far as I understand most agree that 15um radiation is absorbed near Earth Surface perhaps most think that it we have rapid saturation near Earth Surface.
So I repeat in the absence of IR active CO2 I would not expect much change in Earth Surface temperatures certainly not “Snowball Earth”.
Tim Folkerts and Joel Shore make the point
…….” Active volcanoes are also under the sea.
Estimates I have seen suggest that the average upwelling heat from the interior is about 0.1 W/m^w. Even if this number is off by a factor of 10, 1 extra W/m^2 would hardly be a major source of warming for the oceans. Do you have better info on the amount of geothermal energy? “…….
Its not the overall heat supplied to the planet by Active volcanoes under the sea that important here.
Its the local effect of such heat
Active volcanoes under the sea => rapid local heating of H2O
=> vaporization of H2O => rapid radiative effects of H2O vapour
=> rapid cloud formation => rapid radiative effects of H2O clouds
=> enhanced greenhouse effect
=> No Snowball Earth because of the forcing effect of vapourisation effect of Active volcanoes under the sea.
However the volcanoes might not even be necessary see answer to Dave Springer above.
Bryan says:
March 14, 2011 at 12:21 am
Sun doesn’t have significant 4um emission but even if it did H2O has very strong absorption lines in the near infrared – much much more than CO2.
H2O doesn’t have a strong absorption band near 15um. There’s a weak one but the overlap is partial.
Bryan,
For most undersea volcanoes, your process will stop half way thru
Active volcanoes under the sea => rapid local heating of H2O
=> vaporization of H2O => rapid radiative effects of H2O vapour
=> rapid cooling as energy is transferred to tons and tons of very cold water.
Only volcanoes relatively near the surface would create significant amounts of excess vapor. Otherwise the energy will be absorbed by the overall environment.
Also, less than 1% of the solar energy is above 4 um, so the CO2 absorption bands will have a relatively small affect on incoming radiant energy (absorbing maybe 0.1% of incoming energy). The absorption bands near 2 um and 2.5um would have more significant impact.
Finally, i agree that H2O is a significant absorber in the 15um. I agree that most upward 15um radiation from her ground is absorbed near Earth. But for energy balance, the energy that is ultimately emitted from the earth is what most matters. In the stratosphere, there is very little H2O, so the big “dip” near 15 um in the first graphic is clearly the result of CO2, and plays a significant role in the global energy balance.
Harry Dale Huffman says:
March 10, 2011 at 7:25 am
“A proper comparison of the atmospheric temperatures of Venus and Earth”
The Venusian atmosphere has sulfate aerosol layers and no water vapor. It has a day length of 243 earth days and a axial tilt of 178 degrees. Any competent physical scientist wouldn’t make a comparison which says something about you. A competent physical scientist compares the earth to the moon. The average temperature of moon as measured by two Apollo experiments profiling regolith temperature at various depths is -23C which is the constant year-round temperature of the regolith at a depth of 100 centimeters or greater. Presumably since the earth and moon are made of the same stuff and have similar albedos the earth would be -23C without greenhouse gases.
Put that in your physically competent pipe and smoke it.
“my Venus analysis is easily verified by any competent scientist, and should have been confronted and generally accepted nearly 20 years ago”
It should have been confronted and rejected 20 years ago. But hey, I did that just now. Better late than never.
Tim Folkerts says:
March 14, 2011 at 3:07 am
“But for energy balance, the energy that is ultimately emitted from the earth is what most matters. In the stratosphere, there is very little H2O, so the big “dip” near 15 um in the first graphic is clearly the result of CO2, and plays a significant role in the global energy balance.”
The big dip is evident in the very dry air over the frozen arctic surface. What you’re seeing is the extinction altitude where the CO2 in the air column has absorbed all the available 15um energy and thermalized it so that all you see beyond that point is a continuous blackbody spectrum of the considerably colder air at the extinction altitude. The temperature is 40K lower which corresponds to an altitude above the surface of 4 kilometers using the dry adiabatic lapse rate of 1K per 100 meters.
The same graph looking down over the tropical pacific shows an extinction altitude of 8 kilometers. This is because the high water vapor content of the atmosphere over the tropical pacific keeps the upwelling 15um radiation well thermalized in the first couple of kilometers or so above the surface where the air eventually dries out due to falling below freezing temperature. So the air still has a continuous blackbody spectrum at that altitude. Then CO2 takes over but since it’s now thinner it takes a greater column length to reach extinction.
CO2 should therefore be expected to have far less surface warming effect in the tropics because the same H2O that is insulating the surface in the tropics will also insulate the surface against downwelling radiation from the CO2 in the dry air above it. Indeed this is exactly what we observe – far more “global warming” in the high latitudes than the low ones.
Ironically warming in the high latitudes with little change in the low latitudes is exactly what we’d wish for in the way of beneficial climate change. Longer growing seasons in the places that could use longer growing seasons and no change elsewhere. Then consider that plants grow faster using less water as CO2 levels rise and it becomes clear that increasing atmospheric CO2 is nothing short of a wonderful thing which makes the CAGW position irony cubed. I’d be amused if there weren’t so many people in high places who are taking advantage of the CAGW farce for personal and political gain. The only good thing about CAGW is that it inspires a desire in the unwashed masses to find alternatives to fossil fuel use. I strongly believe there are cheaper ways to supply our growing energy needs and cheaper energy means a higher standard of living for everyone. So alternative energy R&D is ultimately a good thing so long as we don’t prematurely kill the fossil goose laying the golden eggs before we have better goose to replace her. Just for the record (again) I believe direct conversion of sunlight, wastewater, and CO2 into liquid and gaseous fuels (diesel, ethanol, methane) by genetically engineered microrganism that can thrive on land unsuitable for agriculture is that better cheaper source of energy and unlike just about anything else on the table as these fuels fit seamlessly into extant infrastructure.
The great variability of H2O content in lower latitudes makes it a poor place to try isolating the effect of CO2 although the comparison between wet and dry air is definitely instructive.
Dave Springer
Check out graphs for CO2 and H2O in Ira Glickstein previous post;
http://wattsupwiththat.com/2011/03/10/visualizing-the-greenhouse-effect-emission-spectra/
Unless the graphs Ira Glickstein posted are false, they show H2O as a significant absorber around 15um.
Now there are about 30 H2O molecules to every CO2 molecule on average so I suggest there is some merit in the following inequation;
30x(medium effect(H2O) > one strong effect(CO2)
Tim Folkerts above seems to agree with me that most absorption is near the surface but its not a significant point.
I think you agree with me that on the whole an IR inactive CO2 would lead to more 4um solar reaching the surface but you dispute the quantity.
Then at the end you appear to agree with me!
“So I repeat in the absence of IR active CO2 I would not expect much change in Earth Surface temperatures certainly not “Snowball Earth”.”
So I fail to understand the use of the term “crap”.
Such expressions are completely inappropriate particularly for someone like yourself who believes in “intelligent design”.
What would the Great Architect in the sky think!
Tim Folkerts says:
…..”Only volcanoes relatively near the surface would create significant amounts of excess vapor. Otherwise the energy will be absorbed by the overall environment.”…
The local effect only requires that the local surface water temperature > zero centigrade or even less (salt water).
This Snowball Earth scenario is based on a rickety pile of questionable assumptions.
They often neglected 99% of the atmosphere that does not IR radiate(N2,O2) can return heat to the surface by conduction.
The massive thermal capacity of the Oceans.
The daily Earth spin exposing each half of the planet in succession.
All these and more factors contribute to keep the Earth Surface temperature stable.
Why then is CO2 demonised and the economic dislocation implied in its elimination as a fuel source contemplated.
to Dave Springer
you wrote: ((Au contaire. Just off the top of my head the antarctic polar vortex strength can lower atmospheric pressure at the surface which causes the atmosphere to cool by expansion and it can also suck cold air from the stratosphere down to the surface.))
lol. You still don’t get it!
You are chasing canards.
The polar vortex, for example, makes no difference. And the polar vortex does not originate from the surface of the earth (ON earth is the term I used). It is a purely atmospheric effect. It is the energy content of the atmosphere that is important.
The simple fact of the matter is that CO2 has increased in the atmosphere over the central Antarctic corresponding to CO2 increases throughout the planet and its atmosphere. It has been measured.
And yet, there is no warming from that increase of CO2 in Antarctica. It has been measured.
If the atmospheric energy content was going UP, the LOWS recorded at Antarctica would be going UP. But they are not!
The UV doesn’t matter. The polar vortex doesn’t matter.
There is no AGW effect whatsoever in the Antarctic temperature data.
That is the only thing that is important to the discussions at hand.
If you wish to speculate on chasing canards, that is fine. But until you can provide better data, that is all that your thinking is, figments of your imagination.
As a scientist, or engineer, you HAVE to learn to separate fact from fiction to make decisions. You have to go with the best data possible. It is the only way that you can make PRACTICAL decisions with any certainty whatsoever.
I seem to remember that you have written here that you spent many years working in manufacturing for Dell Computers. Have you forgotten the decision making processes you had to use when you worked for Dell Computers?
Domenic says:
March 14, 2011 at 5:25 am
I’d appreciate some links to back up your claims that the polar vortex and ozone hole have no effect on antarctic surface temperatures. I gave you links that link them to surface temperatures. You just waved your hands around and denied it. I’m ignoring your hand waving.
O H Dahlsveen says:
You are getting yourself tied in knots because you don’t understand how radiative balance works. There is no rule that says that the earth can’t emit more than it absorbs from the original solar radiation; an object simply radiates according to its temperature. The rule is that the energy flows must balance in the end. They do…and this is because the surface receives additional radiation (the so-called “back radiation”) from the atmosphere.
In a more extreme case, because of its thick clouds, the amount of solar radiation actually reaching Venus’s surface is very small (only a few W/m^2 as I vaguely recall), but its surface still radiates a heck of a lot more than this!
The diagram is not following the path of individual photons. It is showing you the net energy flows. In particular, it includes multiple absorptions and emissions from the surface and the atmosphere.
That somebody is you.
Ah…How do you think the atmosphere gets to be at a temperature such that it emits radiation if not by absorbing some too?
Look, show a little bit of thought here: Don’t you think that if this diagram was so trivially wrong in the ways you think it is, other scientists in the field would notice that? Or do you think they are all in some grand collusion? I wouldn’t mind if you framed your post as, “Clearly, I don’t understand that diagram because…” Try having a little humility when you are trying to comprehend something in the scientific literature rather than immediately jumping to the conclusion that they are mistaken. It will save you a lot of embarrassment.
davidmhuffer says:
Actually, I said that I was in Chapter 4 (and have skimmed a few other parts). That’s nearly halfway through the book, not “barely past the introduction”.
I didn’t say that I didn’t understand it. In fact, in a subsequent post, I noted that the word “struggling” that I had used in a previous post was too strong a word. At any rate, I think this is another example of the Dunning-Kruger effect ( http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect ) in action…I may not know as much as I’d like to, but I know enough to appreciate what I don’t know, a self-awareness that many people here don’t seem to suffer from.
Domenic says:
Dave Springer already addressed this to some degree but I wanted to add one further point in addition to his: Of course there is something that could drive the temperature down there relative to what it was before, namely less transfer of heat from other parts of the planet. (When you say nothing can drive it down, you are confused about what you mean by “down”, i.e., “down” relative to what. The answer is down relative to how cold things were before CO2 levels increased…but that initial state is very unlikely to have had zero transfer of heat from the warmer climes. In fact, there is a lot of poleward transfer of heat on the earth and a change in circulation that lessens that transfer can indeed cause the temperature there to get colder [or fail to warm very much].)
to Dave Springer
lol. You still don’t get it!
Sit still and think it through carefully for a moment instead of chasing your tail.
“If the atmospheric energy content was going UP, the LOWS recorded at Antarctica would be going UP. But they are not!”
Regardless of the atmospheric mechanism.
If you cannot see that, then you are completely lost and will never ‘get it’.
Bryan,
My point was that deep sea volcanoes will not produce ‘rapid cloud formation’. The thermal energy will be so diffused by the time it reaches the surface that it will be indistinguishable from any other energy. Sure, it will result in a small amount of extra evaporation where upwelling of deep sea currents occurs, but (barring evidence to the contrary), it is reasonable to assume that the energy from this is a fairly steady (over geological or climate change timeframes). Hence cloud formation will not have any “rapid” change.
Since “some also exist in shallow water” these volcanoes could produce “rapid cloud formation”, but again, this will be a minuscule part of the evaporation from the ocean and hence play only a small (and, once again, relatively steady) role in H2O in the atmosphere. (Unless you can provide evidence of increased volcanic activity in the last few decades).
Bryan says:
I think you have a fundamental misunderstanding of how the greenhouse effect works. When radiation gets absorbed, it also ends up being re-emitted. The radiation absorbed very near the ground and then re-emitted will be re-emitted with approximately the same blackbody temperature as the ground and hence there will not be a significant dip in the radiation spectrum at that wavelength as seen from space. However, when radiation is absorbed higher in the atmosphere where it is colder, there is a dip in the radiation seen from space because the re-emission occurs from matter at this colder temperature.
Thus, when you look at the plots of radiation as seen from satellites that are shown in this post, what you want to interpret it as showing is the temperature associated with the level in the atmosphere where most of the radiation that successfully escapes into space is coming from. (That is why the first figure shows all those blackbody curves for different temperatures.) Radiation from levels lower (and warmer) than this is very unlikely to successfully escape without being absorbed and radiation from levels higher (and colder) than this is less because cold objects radiate less.
The effect of adding more greenhouse gases is to raise the effective radiating level from which most of the radiation escapes into space. It is not so much an issue of causing more absorption (since radiation can be re-emitted) as it is an issue of where the absorption occurs in the atmosphere.
@Dominec
The only thing I don’t get is how someone thinks handwaving behind an anonymous internet id will be taken seriously by anyone. You’re in denial. Increases in aerosols, dust, and ice particles over Antarctica are yet another mechanism that can drive temperature down. I don’t think it’s matter of you don’t get it but rather one of you willfully won’t get it.