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CO2 is not the only driver of climate

Posted on 25 October 2009 by John Cook

Climate scientists tend to go on a bit about CO2. However, as readers often point out, CO2 is not the only driver of climate. There are a myriad of other radiative forcings that affect the planet's energy imbalance. Volcanoes, solar variations, clouds, methane, aerosols - these all change the way energy enters and/or leaves our climate. So why the focus on CO2? Is it because scientists are all hysterical treehuggers determined to run peoples' lives with a one world government? Or is there a rational, scientific reason for this CO2 preoccupation? Let's find out which...

When I first started investigating global warming science, I attempted to discern the cause by a process of elimination. I studied all possible causes and ruled out any that couldn't be causing all the warming. As my understanding grew, I came to realise this was an inappropriate approach. Understanding what drives climate does not occur by a process of elimination. It's happens by a process of integration. There are many influences of climate and they all need to be considered together to gain the full picture.

For clarity, let me note a few definitions. Radiative forcing is loosely defined as the change in net energy flow at the top of the atmosphere. In this post, we're talking about the radiative forcing from 1750 to 2005. Values are taken from Chapter 2 of the IPCC AR4 which in turn took all their values from peer reviewed papers - apologies that I was too lazy to cite all the original sources. Positive radiative forcing has a warming effect (so obviously, negative radiative forcing has a cooling effect).

  • Surface Albedo has changed due to activity such as deforestation. This increases the Earth's albedo - the planet's surface is more reflective. Consequently, more sunlight is reflected directly back into space, giving a cooling effect of -0.2 Wm-2.
  • Ozone affects the climate in two ways. The depletion of stratospheric ozone is estimated to have had a cooling effect of -0.05 Wm-2. Increasing tropospheric ozone has had a warming effect of +0.35 Wm-2.
  • Solar variations affect climate in various ways. The change in incoming Total Solar Irradiance (TSI) has a direct radiative forcing. There is an indirect effect from UV light which modifies the stratosphere. The radiative forcing from solar variations since pre-industrial times is estimated at +0.12 Wm-2. Note that the radiative forcing from solar variations may be amplified by a possible link between galactic cosmic rays and clouds. However, considering the sun has shown a slight cooling trend over the last 30 years, an amplified forcing from solar variations would mean a greater cooling effect on global temperatures during the modern warming trend over the last 35 years.
  • Volcanoes send sulfate aerosols into the stratosphere. These reflect sunlight, cooling the earth. A strong volcanic eruption can have a radiative forcing effect of up to -3 Wm-2. However, the effect of volcanic activity is transitory - over several years, the aerosols wash out of the atmosphere and any long term forcing is removed.
  • Aerosols have two effects on climate. They have a direct cooling effect by reflecting sunlight - this is calculated from observations to be -0.5 Wm-2. They also have an indirect effect by affecting the formation of clouds which in turn affect the Earth's albedo. The trend in cloud cover is one of increasing albedo which means a cooling effect of -0.7 Wm-2.
  • Stratospheric Water Vapour has increased due to oxidation of methane and had a slight warming effect of +0.07 Wm-2.
  • Linear Contrails from aviation have a slight warming effect of +0.01 Wm-2.
  • Nitrous Oxide reached a concentration of 319ppb in 2005. As a greenhouse gas, this contributes warming of  +0.16 Wm-2.
  • Halocarbons (eg - CFC's) were used extensively in refrigeration and other industrial processes before they were found to cause stratospheric ozone depletion. As a greenhouse gas, they cause warming of +0.337 Wm-2.
  • Methane is actually a more potent greenhouse gas than CO2. Pre-industrial methane levels, determined from ice core measurements, were around 715 parts per billion (ppb). Currently methane rates are at 1774 ppb (eg - 1.774 parts per million). The radiative forcing from methane is +0.48 Wm-2.
  • CO2 levels have increased from around 280 parts per million (ppm) in pre-industrial times to 384 ppm in 2009. The radiative forcing from CO2 is +1.66 Wm-2. CO2 forcing is also increasing at a rate greater than any decade since 1750.

Here's a visual summary of the various radiative forcings:


Figure 1: Global mean radiative. Anthropogenic RFs and the natural direct solar RF are shown. (IPCC AR4 Figure 2.20a)

Putting it all together, Figure 2 compares the warming from human caused greenhouse gases to the total radiative forcing from all human sources.


Figure 2: Probability distribution functions (PDFs) from combining anthropogenic radiative forcings. Three cases are shown: the total of all anthropogenic radiative forcings (block filled red curve); Long-lived greenhouse gases and ozone radiative forcings (dashed red curve); and aerosol direct and cloud albedo radiative forcings (dashed blue curve). Surface albedo, contrails and stratospheric water vapour RFs are included in the total curve but not in the others. Natural radiative forcings (solar and volcanic) are not included in these three PDFs. (IPCC AR4 Figure 2.20b)

Greenhouse gases and ozone contribute warming of +2.9 Wm-2. The majority of this is from CO2 (+1.66 Wm-2). This warming is offset by anthropogenic aerosols, reducing the total human caused warming to 1.6 Wm-2. So surprisingly, the warming from CO2 actually exceeds the final total radiative forcing. If ever asked how much CO2 contributes to global warming, you could say "all of it... and some!" But a more appropriate response would be to list the various contributors of forcing, both negative and positive, although this may cause the questioner's eyes to glaze over (and wish they'd never asked). Framing science is never easy.

The other important point to glean from Figure 2 is that we have a relatively high understanding of greenhouse gas radiative forcing. The probability density function (PDF) shows a much higher probability than the aerosols PDF, meaning the uncertainty associated with greenhouse gas forcing is much lower. This degree of confidence is also confirmed by experimental observations from both satellites and surface measurements which confirm the degree of enhanced greenhouse effect from rising greenhouse gases.

So bringing it all together, there are two reasons for the focus on CO2:

  1. CO2 is the most dominant radiative forcing
  2. CO2 radiative forcing is increasing faster than any other forcing

UPDATE: just read an interview with climate scientist Ken Caldeira which focuses on the issue of geoengineering. But one particular quote summed up the issues discussed above:

Question: They also write that you are convinced that human activity is responsible for “some” global warming. What does that mean?

Caldeira: I don’t think we can say with certainty whether we’re responsible for 90 percent of it or we might be responsible for 110 percent of it. But the vast majority of global warming, I believe, is due to human release of greenhouse gases to the atmosphere.

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Comments 151 to 200 out of 268:

  1. Tom Dayton - Re:Your Post#146 What "tone" didn't you like? Was it: Why don't you save us all a lot of time and BACK-UP your Posts with Physics Links BEFORE posting your un-informed and continually "WRONG OPINIONS" ?? --------- You said... "But objects that radiate have no obligation to do so continuously. Consider two very cold objects--both so close to absolute zero that they infrequently radiate. One is slightly warmer than the other. Most of the time, neither is radiating." Perhaps the "crux of your confusion" is that you have not actually read the Stefan-Boltzmann Law (which I have posted numerous times)? Here is the Stefan-Boltzmann Law again: P/A = BC*T^4 http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/stefan.html ----- Here is the Heat Transfer equation: P = e*BC*A(T^4 – Tc^4) Where P = net radiated power (Watts), e = emissivity, BC = Stefan’s constant, A = area, T = temperature of radiator and Tc = temperature of the surroundings or another body. ..when rearranged gives P/A = e*BC*T^4 – e*BC*Tc^4 (Watts/m^2) --------------------------- Gee, it seems that if T or Tc is greater than absolute zero they will radiate. Where do you get..."Consider two very cold objects--both so close to absolute zero that they infrequently radiate." What Law of Science did you base that statement on? Really....WHERE did it come from? ----- Here is another statement made by you...."One is slightly warmer than the other. Most of the time, neither is radiating." Again, What Law of Science did you base that statement on?...and where did it come from? -------- Both your statements are CLEARLY dis-proven by The Stefan-Boltzmann Law. Why don't you Post back-up Physics for your statements? Like I said, I am tired of constantly re-posting Laws of Science that your "opinions" are in direct conflict with! -------------- After making the totally wrong statement: "But objects that radiate have no obligation to do so continuously. Consider two very cold objects--both so close to absolute zero that they infrequently radiate. One is slightly warmer than the other. Most of the time, neither is radiating." You continue making false statements like: "Now the cooler object emits a single photon/wavepulse, which travels to the warmer object while the warmer object happens to not emit. So the wave from the cooler object makes it all the way to the warmer object without interference, until it hits the warmer object and the warmer object absorbs that energy. The warmer object thereby is warmed by the cooler object." It is hilarious to see a false statement that violates The Stefan-Boltzmann Law used to justify another false statement that violates the 2nd Law of Thermodynamics! I think I have made my point...and no further comment is necessary.
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  2. Philippe Chantreau - re:your post #147 Re: Mass of a Photon I had ALREADY posted this Physics link in my post#126 Photon "In physics, a photon is an elementary particle, the quantum of the electromagnetic field and the basic "unit" of light and all other forms of electromagnetic radiation. It is also the force CARRIER for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances" http://en.wikipedia.org/wiki/Photon I also stated in the same post: "- Photons have zero Mass." and "Is it so surprising that opposing EM fields and corresponding Forces will only move the zero mass Photon energy in the direction of the larger force? The “block of wood” analogy should be apparent except that, unlike a “block of wood”, a Photon has zero mass." I am tired of constantly re-posting Physics links and repeating what I have already posted. --------------- You asked... "Obviously, the photon going through numerous absorbtions and re-emissions will take longer to reach the TOA. It means that the atmosphere imposes a longer residence time to IR photons in the periphery of the Earth. Now I'm wondering all the things that happen if the atmospheric composition is changed in a way that further increases that residence time." You can wonder all you like. I have already answered your question in my Post#144 and gave a calculation for the time required to send a signal from the Earth's surface to a satellite 36,000 km away. It takes 0.12 second. How many "Days" did you think it took? I am tired of constantly re-posting Physics links and repeating what I have already posted. ------------------ You said... "Vectors are not physical phenomena, they are ways to represent them. You can play around with formulas and plug numbers in them, that does not provide us with an understanding of the principles described by them." Vectors are used to represent Forces and any quantity that has both a magnitude and a direction...like EM fields. Vector EM fields are another way of describing "Interference" that occurs in the time domain when EM waves interact. I have already provided these Physics Links that completely explains constructive and destructive "Interference" and how they produce a NEW EM WAVE and can completely cancel opposing EM waves. Interference (wave propagation) "In physics, interference is the addition (superposition) of two or more waves that results in a NEW WAVE pattern." There is even an animation of continuous waves creating a continouous Interference pattern that produces a NEW WAVE that is CONTINUOUS! http://en.wikipedia.org/wiki/Interference_(wave_propagation) Cancellation of Light (This Bubble link is especially well done...even a child could understand it) http://www.exploratorium.edu/ronh/bubbles/bubble_colors.html http://webexhibits.org/causesofcolor/15F.html http://micro.magnet.fsu.edu/optics/lightandcolor/interference.html I am tired of constantly re-posting Physics links and repeating what I have already posted. -------------------- You asked... "What happens to the photons emitted by a cooler object in the direction of a warmer object? Do they disappear? Do they turn around? Do they anihilate against photons coming from the warmer object? If yes, how exactly does that happen?" I have already answered this in my Post#126 including links to the Physics. Here is a partial re-post: "Propagating Electromagnetic Fields "CARRY" Photon energy. If an Electromagnetic Field has zero magnitude it will not propagate, hence Photon energy cannot move. The Photon energy is CARRIED in the DIRECTION of the LARGER Electromagnetic Field!...and EM fields ARE VECTOR FIELDS!" I am tired of constantly re-posting Physics links and repeating what I have already posted. ---------------------- You asked... "How about the multiple object experiment? What is the net heat flow for object A? None of these thought experiments requires calculations to be answered, the exact values are of no interest, only the principles. According to the principles, what direction of heat flow must object A experience when surrounded by B through B12?" The "superposition" principle applies. Superposition principle "In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems, The net response at a given place and time caused by two or more stimuli is the sum of the responses which would have been caused by each stimulus individually." http://en.wikipedia.org/wiki/Superposition_principle Interference (wave propagation) "In physics, interference is the addition (superposition) of two or more waves that results in a NEW WAVE pattern." There is even an animation of continuous waves creating a continouous Interference pattern that produces a NEW WAVE that is CONTINUOUS! http://en.wikipedia.org/wiki/Interference_(wave_propagation) Here is an additional Physics Links that show multiple sources and how their waves interact. It includes a animation and a resultant radiation pattern for the multiple sources. http://paws.kettering.edu/~drussell/Demos/rad2/mdq.html
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  3. Gord, "Gee, it seems that if T or Tc is greater than absolute zero they will radiate." Can you expand a bit on that?
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  4. About the superposition principle, you say, "The net response at a given place and time caused by two or more stimuli is the sum of the responses which would have been caused by each stimulus individually." According to you, each stimulus individually would have resulted in zero radiation from any B object to object A and a transfer to the B object. So, that would mean that, overall, heat is flowing away from A, is that right? How does a field "carry" photon energy? How can photon energy not move, since by definition a photon moves at the speed of light? Thanks for the links.
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  5. Philippe Chantreau - re:your post #153 Yes, if T or Tc is greater than absolute zero they will both radiate EM fields EMT and EMTc, however "Wave Interference" will occur creating a NEW WAVE pattern that has a Magnitude of [ EMT - EMTc ] and a DIRECTION of propagation towards EMTc. If EMT = EMTc then the "Wave Interference" will produce a NEW WAVE pattern that has a ZERO Magnitude and there will be ZERO propagation. Just like the Bubble Link shows. Cancellation of Light (This Bubble link is especially well done...even a child could understand it) http://www.exploratorium.edu/ronh/bubbles/bubble_colors.html I am tired of constantly re-posting Physics links and repeating what I have already posted. Especially if I just posted it!!! Are you starting to understand why this CONSTANT repetition is really getting TEDIOUS?
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  6. Since you use Wikipedia quite a bit, I believe it is an acceptable source for you. I found this in the article on thermal radiation, can you discuss? http://en.wikipedia.org/wiki/Thermal_radiation "In a practical situation and room-temperature setting, humans lose considerable energy due to thermal radiation. However, the energy lost by emitting infrared heat is partially regained by absorbing the heat of surrounding objects (the remainder resulting from generated heat through metabolism). Human skin has an emissivity of very close to 1.0 .[3] Using the formulas below then shows a human being, roughly 2 square meter in area, and about 307 kelvins in temperature, continuously radiates about 1000 watts. However, if people are indoors, surrounded by surfaces at 296 K, they receive back about 900 watts from the wall, ceiling, and other surroundings, so the net loss is only about 100 watts." Note that the surfaces mentioned are colder than the human body considered (296 vs 307K). Isn't that normally impossible? It very much corresponds to the idea I had that bodies radiate and absorb and the net heat transfer depends on the difference between the 2, does it not?
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  7. Philippe Chantreau - Re:your Post #154 First, I did not write or invent the Superposition Principle or ANY of the other Physics links I referenced. Second, I am not your Teacher. Third, I suggest that YOU investigate the Physics for YOURSELF....or take some Electrical Engineering Courses if you have the academic qualifications to do so. Finally, replying to your posts has become an exercise of CONSTANT repetition is really getting TEDIOUS !!!
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  8. Gord, "The equation P = e*BC*A(T^4 – Tc^4) describes much, much more than the Stefan-Boltzmann Law!" And then, can you describe what this equation tells us? And how it applies to the earth-atmosphere system?
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  9. Gord, you managed a single polite response and then degenerated below your previous low level. Since you like moving pictures, here is one showing a moving wave packet (photon) that you keep denying exists as a discrete entity: http://physics.gac.edu/~chuck/PRENHALL/Chapter%2031/AABXTEI0.html?I1.x=8&I1.y=29 One of your favorite sources that you greatly trust, HyperPhysics, has a section on the Earth's atmospheric greenhouse effect, somehow avoiding mention of its violation of the second law. How can the author of that site be so correct about the Stefan-Boltzmann law, but so wrong about the greenhouse effect? Maybe you should go argue with Roy Spencer, since even he realizes that the "violation of the second law" argument is so wrong that it is bizarre. You are no longer amusing to play with.
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  10. Riccardo - re:your post#158 That's exactly what I did in my Post#150 !!! "As you can see: The equation P = e*BC*A(T^4 – Tc^4) describes much, much more than the Stefan-Boltzmann Law! It is a representation of numerous Laws of Science, Principles of Science and Actual Measurements." Also see my Posts #16,#27,#34,#69, and #144. I am tired of constantly re-posting Physics links and repeating what I have already posted.
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  11. Tom Dayton - re:your post #159 Your link does not work. Physlet Illustration: Emission in the Bohr Model http://physics.gac.edu/~chuck/PRENHALL/Chapter%2031/AABXTEI0.html?I1.x=8&I1.y=29 PS: "Packets" are not continuous. ----------- Greenhouse Effect http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/grnhse.html#c1 There are numerous authors for Hyperphysics. The Physics Link equations and descriptions are found in Physics text books. However, this "author" claims that "Infared emission is blocked by the glass" An obvious "error" as ANY spectral emission of a standard Tungsten Light Bulb will show. By the way, in case you didn't notice....it describes a "Glass Greenhouse"! ----------- Hmmm, so Roy Spencer is a "pathological denialist"....not very POLITE are you? ------------- Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics. International Journal of Modern Physics B, Vol. 23, No. 3 (30 January 2009), 275-364 Notice what is said in the Abstract: "The atmospheric greenhouse effect, an idea that authors trace back to the traditional works of Fourier 1824, Tyndall 1861, and Arrhenius 1896, and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system." AND... "According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation." http://arxiv.org/abs/0707.1161
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  12. After answering numerous questions (over and over again), I have yet to receive even ONE answer to these simple questions: Any luck coming up with these items? 1. Please supply ANY Law of Science that supports the "Greenhouse Effect" and AGW. 2. Please supply ANY Measurement that shows that CO2 in a Colder Atmosphere can Heat up a Warmer Earth. 3. Please describe (and back-up by Physics) how a -20 deg C atmosphere can heat a -18 deg C Earth up by 33 deg C to a whopping +15 deg C. There has been over $200 Billion spent on AGW, there are thousands of papers on AGW, the IPCC has written several reports on it and countless "Scientists" say AGW is real. So, this should a "snap" for you to produce....right? Good Luck! -------------- Also, NOBODY has even tried to do the extremely simple calculation in my Heat Transfer example in my Post#34. Now let’s see YOUR calculations with energy flowing from the colder body to the hotter body. Do the calculations until thermal equilibrium is achieved. Remember that there is ONLY one energy source emitting 5.67 watts/m^2 and the Law of Conservation of Energy says “Energy cannot be created or destroyed”. GOOD LUCK!
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  13. That's exactly what I'm doing. I'm sincerely trying to understand and I have been getting info as we exchange posts, isn't that how a fruitful discussion should happen? I am well aware that you did not discover the superposition principle or any other law discussed here. Let's consider the superposition principle and the multiple object experiment: A radiates 90W. B radiates 60W. Net heat flow -30W from A, correct? If we apply the superposition principle with 12 B objects, A radiates 360W total. That's a little strange since the total energy radiated by all the B objects is 720W and A is still only 90W. What's wrong with this picture? Clearly the superposition principle does not apply in this case. OTOH, if we apply a treatment more like in the Wiki article on thermal radiation above, A absorbs 630W, which seems to make more sense but should be impossible with your interpretation of the 2nd law, since none of the B objects should be able to individually radiate anything toward A. What gives?
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  14. Gord Whether you are right or wrong, you have fought heroically. Apparently, Tom Dayton is not serious and is just here to play with people's heads.
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  15. Philippe Chantreau I appreciate the way you answered my question way back (142). That doesnt mean I agree with everything you said, however it was thoughtful and respectful.
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  16. Philippe Chantreau - re:your post #163 The superposition principle always applies. A radiates 90. B1 radiates 60. Field between A and B1 is 30 towards B1. B1 receives 30 additional so it now Radiates 60 + 30 = 90. A and B1 are now in thermal equilibrium. A and B1 can now be considered as a single object, call it X ...and radiates 90. X radiates 90. B2 radiates 60. Field between X and B2 is 30 towards B2. B2 receives 30 additional so it now Radiates 60 + 30 = 90. X and B2 are now in thermal equilibrium. X and B2 can now be considered as a single object, call it X ...and radiates 90. X radiates 90. B3 radiates 60. etc. At the end they are all in thermal equilibrium....radiating 90. ------------------------- The Wiki article is in error. There are many people that don't understand the Physics. The article also says this: "This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (October 2007)" http://en.wikipedia.org/wiki/Thermal_radiation See: Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics. International Journal of Modern Physics B, Vol. 23, No. 3 (30 January 2009), 275-364 http://arxiv.org/abs/0707.1161 --------------- Now answer my questions in my post#162
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  17. You say "Field between A and B1 is 30 towards B1. B1 receives 30 additional so it now Radiates 60 + 30 = 90. A and B1 are now in thermal equilibrium." How is that possible? The 30 is already the result of the subtraction of 60 to 90, and we add the 60 again? You're suggesting that not only B is actually radiating 60 toward A, which you indicated earlier was impossible but also that it is radiating it twice.
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  18. Philippe Chantreau - re: your Post#167 A radiates 90. B1 radiates 60. The field between A and B1 is 30 towards B1. (2nd Law, Heat Transfer equation, Vector addition and Interference) When B1 receives and absorbs the 30 it HAS to radiate it. B1 was already radiating 60 so now it HAS to radiate 30+60 = 90.(Stefan-Boltzmann Law and The Law of Conservation of Energy) That's how thermal equilibrium is achieved. Now A and B1 are both radiating 90. (Zero heat transfer between them...2nd Law, Heat Transfer equation, Vector addition and Interference) This is EXACTLY what I have said in ALL my posts including the extremely simple calculation in my Heat Transfer example in my Post#34. ------------------- Now, answer MY questions in my post#162 !!!!
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  19. I do not believe that the Wiki article is in error. The reasoning throughout the text is terse and consistent. Where is the error exactly? The disclaimer certainly does not mean that much. Similar disclaimers exist for Wiki links you've used. The downward IR radiation has been observed and measured, a number of papers analyzing that have been mentioned on this site. You were mentioning earlier vector addition of field vectors that, in effect, are identical to the radiation/absorbtion idea that I and Wiki describe. It is formulated differently but it describes exactly the physical phenomenon and contradicts some of your own statements. A comment to G&T (2009) was submitted to IJMPB. You're probably not interested but other readers might be: http://rabett-run-labs.googlegroups.com/web/G%26T2.11.doc?hl=en&gda=GiEkiT8AAAAXmxShcFP2xrtZ1iQa9EYObLHe1BSUDn5EEukXYSRaprw7opP7C43-G-AfaR61VoGccyFKn-rNKC-d1pM_IdV0 Hope john can make that link look better. There is a number of problems with G&T.
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  20. Philippe Chantreau - Are you going to answer MY questions in my Post#162 or not?
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  21. That last link contains the answers to your post 162. Too much to quote in here, with graphs etc, and I also have other things needing my attention.
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  22. Philippe Chantreau - Exactly as suspected. Zip, Nada, Zero answers. PS: Don't ask me any more questions until you answer mine.
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  23. Gord, "I am tired of constantly re-posting Physics links and repeating what I have already posted. " I'm tired too to not having an answer and to read always the very same trivial Physics 101. And indeed you didn't answer but just repost the same general well-know basic physics without any attemp to explain and use those physics. Don't repost anything, it's worthless if you can't apply it. So again the very same question (you know, it's much easier to copy and paste than elaborate) if you mind to answer: can you describe what this equation tells us? And how it applies to the earth-atmosphere system? In case you do not want to answer, feel free ignore me; but please do not copy and paste any more basic physics.
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  24. Ricardo - I will feel free to ignore you. Saves a lot of time, especially the constant repetion of my posts and "basic physics". PS: Don't ask me any more questions until you answer mine.
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  25. Philippe Chantreau - It would REALLY be interesting if you would do the calculations for YOUR OWN example. I already did it in my post#166. Let's see YOU do the same calculation for YOUR OWN example, to temperature equiibrium...with heat flowing from cold to hot! I can hardly wait to see that!
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  26. Gord, that's ok for me, you don't want to answer and, as you say, you couldn't do it without copy and paste. You might call it talking science, I don't. P.S. "PS: Don't ask me any more questions until you answer mine." Quite intimidating, isn't it? :D And by the way, i could not see any question, at least not in the last posts. Maybe they got lost in the meanders of the copy and paste.
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  27. Last time I checked... "Any luck coming up with these items?" is a QUESTION. ------------------- Funny how I have to keep on repeating things (over and over). Is there too much CO2 in the air? Swine flu? There must be some explaination.
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  28. Gord, let me understand you clearly: Greenhouse gases(GG) are hypothesized to be transparent to visible light and capable of absorbing and emitting in the infrared. Given that proposition, it seems to me that there are three ways to disagree with the GH effect. #1. The gases supposed to be GG cannot do what they are claimed to. #2. There is no infrared energy available for the GG to absorb. #3. GG absorb and emit infrared energy, but this has no effect on the temperature of the Earth's surface. Which of these three objections do you subscribe to(or is there another possibility I have missed)? Cheers, :)
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  29. Gord, that link to the photon animation works fine for me, but I've also made the link clickable here. Open two browser windows side by side. In each window display that animation. Imagine that each is a different atom. Notice that there need not be synchronization between the two atoms' emissions. Even when the two atoms happen to emit simultaneously, usually they will emit in directions other than toward each other. If the two atoms emit infrequently enough, there will be times when a wave packet (photon) from atom A travels all the way to atom B without encountering a photon coming from B to A. Likewise, sometimes a wave packet will travel from B to A unopposed. In those cases, there is no summation/interference of two waves heading toward each other, because there is only one wave during that time frame. The temperatures of A and B are irrelevant to those individual events. Atom A can be hotter than atom B, without preventing the occasional passage of a wave packet (photon) from B to A. Radiation is discrete, not continuous, at this low level of analysis. It doesn't matter how often these situations of unopposed wave packet transition from cooler to warmer happens. The existence of even one such situation invalidates your interpretation of the second law of thermodynamics.
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  30. Well you did not really answer my questions in 149 either. I have no problem waiting for that until I read more through the response to G&T that was sent to IJMPB. I do have other things to do too.
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  31. I'm still considering all the implications of this, and it really does not seem to make sense. It would imply that a radiant barrier is impossible. Yet radiant barriers are used from homes to spacecrafts.
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  32. Tom Dayton - re:your post #179 The animation/simulation in your link does not work. ----------------- You said... "Radiation is discrete, not continuous, at this low level of analysis." Exactly, therefore it is not applicable. In the real world, ALL objects above absolute zero will radiate continuously and Interference will also be continuous.
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  33. shawnhet - re:your post#178 The closest is #3. "GG absorb and emit infrared energy, but this has no effect on the temperature of the Earth's surface." ------------------------------ There is a distinct difference between Greenhouse Gases and the Greenhouse Effect. Greenhouse gases in the atmosphere will absorb IR energy and heat up, but they only heat up to an average of -20 deg C and the Earth has an average temp of +15 deg C. The Greenhouse Effect says that the -20 deg C atmosphere will heat the warmer Earth. The infrared energy from the colder atmosphere cannot reach let alone heat a warmer Earth. This is proven by the violation of several Laws of Science and ALL actual measurements.
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  34. Aside from the global "average", which is normally warmer, air or the surface? I would say surface except for maybe snow on a sunny day, and maybe air vs water in the some circumstances. (just musing) Gord If I may ask a question... are you aware of any exceptions outside of the average temps you cite?. In which case I am just wondering if you would allow greenhouse warming in these specific cases...
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  35. There is a number of papers that present measurements of downwelling IR radiation. This link shows the composition of sunlight. http://en.wikipedia.org/wiki/File:MODIS_ATM_solar_irradiance.jpg. It looks like it's lacking at the wave lengths of GH gases Nevertheless IR at these wave lengths does reach the surface, as measured in numnerous studies. This book is interesting. The measurements presented by Liou show that the downward IR flux increases with decreasing altitude, indicating an atmospheric source. Dunno if that link will work, the book is: An Introduction to Atmospheric Radiation by Kuo-Nan Liou. http://books.google.com/books?id=6xUpdPOPLckC&pg=PA164&lpg=PA164&dq=measured+downward+IR&source=bl&ots=NnPMfJXhPy&sig=sRrO6GTGgT_ckcTmdAumr-_9zww&hl=en&ei=p0vxSpX4C4uuswO5jOn4AQ&sa=X&oi=book_result&ct=result&resnum=5&ved=0CBgQ6AEwBA#v=onepage&q=measured%20downward%20IR&f=false This paper also shows measurements of both solar flux and total IR downward flux. http://www.arm.gov/publications/proceedings/conf08/extended_abs/hinkelman_lm.pdf We have already discussed the Evans (2006) paper, also presenting spectroscopic measurements. http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm This is from a quick search, there likely is a lot more out there. So actual measurements of downward IR flux at the wave numbers of greenhouse gases are readily available. To the extent that this is IR radiation, I will consider it satisfies 2) of Gord's post 162 and also contradicts his assertion above that all actual measurements show that the atmosphere does not radiate IR back to the surface. It's been measured for quite some time, there are papers from the 60's treating of it.
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  36. I think there is a misinterpretation of interference hanging around. For the principle of superimposition at any point the resulting wave is simply the sum of the single waves. It can also be zero, but this does not mean that the waves somehow "disappeared". Immagine two identical plane waves propogating in opposite directions and 180° out of phase. The resulting amplitude is zero everywhere but the two waves are still there. Indeed, if you put a mirror anywhere between the two sources you can deflect the waves. In our case it means that the IR flux from the atmosphere travels towards and actually reaches the earth surface. The earth still emits according to its temperature, but the net flux is reduced.
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  37. Gord, you wrote "In the real world, ALL objects above absolute zero will radiate continuously and Interference will also be continuous." That is incorrect. One of the greatest advances in the history of human knowledge was the 20th century realization that "the energy in electromagnetic waves could only be released in 'packets' of energy." Not continuously. Not hypothetically. In the real world. By all objects. The increase in frequency of radiation from increasing the temperature of an object does not mean there is a single, continuous wave whose frequency increases as the temperature increases. Instead, all objects always emit a gaggle of discrete wave packets (photons), each of those individual photons having a single frequency/wavelength. Some of those photons have a high frequency and some have a low frequency. Increasing the temperature of an object causes it to emit, among its gaggle of photons, a greater percentage of the higher frequency photons and a lower percentage of the lower frequency photons. That's why Wikipedia's entry on Thermal Radiation says "The emitted wave frequency of the black body thermal radiation is described by a probability distribution depending only on temperature." "Probability distribution" describes the membership of the gaggle of photons. If you randomly grab one photon out of the gaggle, it will have a particular, definite frequency. Most likely that frequency will be the frequency that is at the peak of the probability distribution. If you grab multiple photons from the gaggle, some of them will have high frequencies and some will have low frequencies. If you plot the number of photons (on the y axis) having a given frequency or wavelength (on the x axis) you will see a distribution that approaches the shape of that theoretical probability distribution as the size of your sample grows. The Properties section explains "Thermal radiation, even at a single temperature, occurs at a wide range of frequencies. How much of each frequency is given by Planck's law of radiation... The main frequency (or color) of the emitted radiation increases as the temperature increases... The total amount of radiation, of all frequencies, goes up very fast as the temperature rises." So my previous example is correct. There exist in the real universe, objects that are so cold that they emit wave packets so infrequently that occasionally a wave packet from one object travels all the way to the other object without encountering a wave packet coming the other way. That happens both from the warmer object to the colder object, and from the colder object to the hotter object. That violates your (Gord's) model of continuous waves emanating continuously from both objects. That means your model of summing/interfering is false in that case. Which means your interpretation of the second law of thermodynamics is false in that case. The second law of thermodynamics is not wrong. Your interpretation of it is. That animation of wave packet emission that I keep linking to, also can be found by Googling "physlet Illustration: emission in the bohr model".
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  38. Gord, have you noticed that even the Wikipedia entry for the Stefan-Boltzmann law (Temperature of the Earth section) explains the atmospheric greenhouse effect without saying that it violates the second law of thermodynamics?
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  39. Gord, now let's extend the emission of thermal energy as wave packets (photons) from two very cold objects to the Earth's surface and atmosphere. Both surface and atmosphere comprise a riot of wildly heterogeneous bits of mass of various shapes, sizes, temperatures, and many other attributes. All those bits individually emit photons. The overall effect is a riot of photons in all manner of directions, having all manner of frequencies, in all manner of phases and timings. There is no single continuous wave of radiation from the surface, nor one from the atmosphere. Your model is incorrect.
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  40. Someone on this thread pointed out to Gord that wave packets (photons) passing from sky to ground, even if they do interact with wave packets going from ground to sky, do their interference thing while they share the same space but do not destroy any of their energy, and after passing each other simply carry on to hit the ground and sky, respectively. (Sorry for not crediting that someone, but I can't find that bit. One example that is close to that phrasing was a recent comment by Riccardo. Here are some places for more explanation of that: PhysLink.com: "This interference pattern is akin to ripples on water that approach each other, form an interference pattern of peaks and troughs and then continue on their way." A longer explanation is at MadSciNetwork
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  41. RSVP - re:your post#184 Yes, there are exceptions where the atmosphere is warmer than the Earth's surface but these cases are by no means the norm. Heat energy, in these rare cases, will flow from a warmer atmosphere to a cooler Earth. Global Warming from the atmosphere, of course is impossible because it would require an average atmospheric temperature to be higher than the Earth surface average temp.
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  42. Re:Interference When waves interfere they produce a NEW WAVE. If the waves that produce the interference are continuous the NEW WAVE will be continuous. If you do any measurement, all you can measure is the NEW WAVE. Example: A radiates 100 w/m^2 UP. B radiates 100 w/m^2 DOWN. A and B are close, no field losses. Between A and B the Field is 0 w/m^2. Any measurement done will give 0 w/m^2. Without knowlege that A and B exist, no measurement can be done between A and B to prove they exist. Interference (wave propagation) "In physics, interference is the addition (superposition) of two or more waves that results in a NEW WAVE pattern." There is even an animation of continuous waves creating a continouous Interference pattern that produces a NEW WAVE that is CONTINUOUS! http://en.wikipedia.org/wiki/Interference_(wave_propagation) Cancellation of Light (This Bubble link is especially well done...even a child could understand it) http://www.exploratorium.edu/ronh/bubbles/bubble_colors.html
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  43. Tom Dayton - re:your post#188 They really managed to get just about everything wrong. "...a much larger fraction of long-wave radiation from the surface of the earth is absorbed or reflected in the atmosphere instead of being radiated away, by greenhouse gases, namely water vapor, carbon dioxide and methane" All objects that "absorb" energy HAS to "radiate" the same amount. (Conservation of Energy) ---------- "Since the emissivity (weighted more in the longer wavelengths where the Earth radiates) is reduced more than than the absorptivity (weighted more in the shorter wavelengths of the Sun's radiation), the equilibrium temperature is higher than the simple black-body calculation estimates, not lower. As a result, the Earth's actual average surface temperature is about 288 K, rather than 279 K." Gee, the Sun was the ONLY energy source in the calculation of the 279 K temp. The Atmosphere and the Earth are NOT ENERGY SOURCES, so how did the Earth manage to jump in temperature to 288 K ???? They CREATED energy. Typical.
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  44. Re: Measurements of Back Radiation. (First try to get this posted was deleted) All direct measurements of Back Radiation use instruments that have their IR detectors cooled far below the -20 deg average atmosphere temperature. The cooled IR detectors make the direct measurements possible, just like the 2nd Law states. I have already posted this along with Instrument specifications in my Post #16. Isn't it funny that these same "scientists" (who absolutely know that these instruments use cooled IR detectors to make their direct Back Radiation possible) then claim that the Back Radiation will heat a warmer Earth? Isn't it funny that these same "scientists" claim that the Back Radiation (324 w/m^2 being absobed by a warmer Earth) EXCEEDS the Solar Energy (168 w/m^2) energy reaching the Earth's surface but never, ever say that we should harness this Phantom Back Radiation as a clean energy source? Isn't it funny that these same "scientists" know that IR Back Radiation (available Day and Night) can be concentrated at the focal point of a parabolic mirror (Solar Oven) never ever mention that Solar Ovens don't produce any warming when pointed at the colder atmosphere Day or Night? There are numerous Mega-Watt Solar Power installations that use parabolic mirrors to boil water which is then used to produce power. Funny how these installation don't produce any power from Back Radiation at night? There are probably hundreds of thousands of Solar Ovens used in 3rd World countries to boil water and cook food. Funny how these installation don't produce any power from Back Radiation at night? Isn't funny that these "scientists" never mention the actual measurements done by the Physics Dept. at Brigham Young University where they use Parabolic Mirror Solar Ovens to freeze water when the Ovens are pointed at the colder atmosphere, Day and Night? (just like the 2nd Law says will happen). Isn't funny how so many people believe that Back Radiation can HEAT A WARMER EARTH when it can't even heat an ounce of water even when the Back Radiation should be concentrated at the Solar Oven's focal point.
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  45. Tom Dayton - re:your post #187 (Second attempt to get this posted, without deletion) You said... "That is incorrect. One of the greatest advances in the history of human knowledge was the 20th century realization that "the energy in electromagnetic waves could only be released in 'packets' of energy." Not continuously. Not hypothetically. In the real world. By all objects." A Photon is released by an atom dropping in energy state....that can be considered to be a Packet of Energy. Multiple atoms releasing multiple photons on a continuous basis will produce a continuous release of Photon Energy. A Photon does not propagate on it's own....the Photon Energy is CARRIED by and Electromagnetic Field having a frequency and wavelength. (EM Fields are NOT PACKETS) Maybe you should have also quoted these statements from the same link: "In physics, a photon is an elementary particle, the quantum of the ELECTROMAGNETIC FIELD and the basic "unit" of light and all other forms of ELECTROMAGNETIC RADIATION. It is also the force CARRIER for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances" "Like all elementary particles, photons are governed by quantum mechanics and will exhibit wave-particle duality – they exhibit properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit WAVE INTERFERENCE, but also act as a particle giving a definite result when quantitative mass is measured." "It also accounted for anomalous observations, including the properties of BLACK BODY RADIATION, that other physicists, most notably Max Planck, had sought to explain using semiclassical models, in which light is still described by Maxwell's equations, but the material objects that emit and absorb light are quantized." ---------------------------- Heat Radiation Radiation is heat transfer by the emission of electromagnetic waves which CARRY energy away from the emitting object. For ordinary temperatures (less than red hot"), the radiation is in the infrared region of the electromagnetic spectrum. The relationship governing radiation from hot objects is called the Stefan-Boltzmann law: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html#c2 --- Properties of electromagnetic waves "An electromagnetic wave, although it CARRIES no mass, does CARRY energy." "A more common way to handle the energy is to look at how much energy is CARRIED by the wave from one place to another." http://physics.bu.edu/~duffy/PY106/EMWaves.html --- Heat flux "Heat flux or thermal flux, sometimes also referred to as heat flux density or heat flow rate intensity is a flow of energy per unit of area per unit of time. In SI units, it is measured in [W·m-2]. It has both a direction and a magnitude so it is a vectorial quantity." http://en.wikipedia.org/wiki/Heat_flux ----------------------------------------------- All bodies that have a temperature will produce an Electromagnetic Field (and carry Photon Energy)...continuously. Black body Planck's Law, Wein's Law and the Stefan-Boltzmann Law will determine the frequencies (a probability function) and magnitude (w/m^2) of the Electromagnetic Fields produced by the body temperature. http://en.wikipedia.org/wiki/Black_body Here is the Stefan-Boltzmann Law again: P/A = BC*T^4 (watts/m^2) http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/stefan.html Clearly, if T is greater than absolute zero an Electromagnetic Field is produced....continuously. Your statement.... "There exist in the real universe, objects that are so cold that they emit wave packets so infrequently that occasionally a wave packet from one object travels all the way to the other object without encountering a wave packet coming the other way." ....is a violation of the Stefan-Boltzmann Law, Planck's Law, Wein's Law and all Electromagnetic Physics! ------------------------------------- PS: Does the Sun blink "on and off" due to "packets" or does it produce continuous waves?
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  46. Tom Dayton - re:your post#189 and #190 (Second attempt to get this posted, without deletion) Here is the Stefan-Boltzmann Law again: P/A = BC*T^4 (watts/m^2) http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/stefan.html Clearly, if T is greater than absolute zero an Electromagnetic Field is produced....continuously. There are no "wave packets". ---------------------------------- Why don't you produce ANY AGW paper that says the Sun's radiation, Earth Radiation or Atmosphere Radiation is in "wave packets"?
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  47. Gord, just to add fuel to the fire, there's one more thing you don't understand, the reason why an IR detector is cooled. The dector can work at room temperature, it is cooled only to have a better the signal to noise ratio. Clearly you're talking of things you don't know.
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  48. I can't believe this attempt to educate Gord has continued on as it has. Not only does he dispute the reality of the greenhouse effect but he also claims quantum mechanics to be flawed in the most fundamental of ways. No discreet wave packets of light according to him? If a new wave pattern results from interference how is it we can detect discreet emitters of radiation such as distant stars? Leptons (photons) do not obey the Pauli Exclusion Principle. Information is not lost as a result of interfering waves, they pass right through each other. Downward "cooler" radiation is not canceled out by "warmer" radiation traveling in the opposite direction. The energy "waves" pass right through each other. Discreet emissions of electromagnetic radiation such as when an electron jumps energy levels within the Bohr model always propagate in all three spatial directions with no direction preferred just as a wave propagates outward in all directions when dropping a stone in water. The squiggle that represents the photon as shown in the model is just there to indicate emission, but the emission is actually as wave-particle duality. The model shows only the "particle" representation.
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  49. WeatherRusty - re:your post#200 I wonder how many times I have to repeat, over and over again, these simple concepts. (see my many, many posts on interference that includes ACTUAL physics links) Here is one link that is so simple that a CHILD CAN UNDERSTAND! Cancellation of Light (This Bubble link is especially well done...even a child could understand it) http://www.exploratorium.edu/ronh/bubbles/bubble_colors.html ------------------------------------ I have repeated this at least 10 times now! What, exactly, don't you understand about interference and light cancellation ???
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  50. Gord wrote "There are no 'wave packets.'" Go to the HyperPhysics site that you trust so much, to the page on Blackbody Radiation. In that diagram, note the line connecting the Blackbody Radiation oval to the Stefan-Boltzmann Law oval. That connecting line says "summed over all wavelengths gives the." In other words, Blackbody Radiation... summed over all wavelengths gives the... Stefan-Boltzmann Law. The Stefan-Boltzmann Law is a merely a convenient summary description of the underlying, more fundamental, entities and behaviors.
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