Summing up the new thread Slaying the Greenhouse Dragon, Part IV on Judy Curry's blog including 700 comments, on my work Computational Blackbody Radiation showing that "back radiation" is fiction, gives the following net result:
- ... I’d like to propose a strengthening of the skeptic argument that downward longwave radiation or DLR, popularly called back radiation, cannot be held responsible for warming the surface of the Earth.
- ... what I’m claiming is not that there is no back radiation but that the only sense in which back radiation warms the Earth is the same sense in which a block of ice next to you warms you.
Judy:
- Back radiation is a phrase, one that I don’t use myself, and it is not a word that is used in technical radiative transfer studies.
- Lets lose the back radiation terminology, we all agree on that.
- I give up back radiation as a misleading phrase.
- Claes has some serious credentials, he is widely published and cited in applied mathematics.
- ... denial of back radiation is such an awkward example to use to illustrate Skepticism. It’s actually an example of denial.
- Perhaps part of the reason for his (Claes) skepticism is the belief that a purely reductionist approach is not the best way to approach physics. If so, he is in good company (even if many do take vigorous exception).
Jeff Glassmann:
- How far should we go when we lose the back radiation terminology ? We will have to throw out Kiehl & Trenberth, Earth’s Annual Global Mean Energy Budget, 2/1/1997. AR4, FAQ 1.1, Figure 1, p. 96.
- And since The term “radiative forcing” has been employed in the IPCC Assessments to denote an externally imposed perturbation in the radiative energy budget of the Earth’s climate system. (TAR, ¶6.1 Radiative Forcing, ¶6.1.1, p. 353), we will have to throw out radiative forcing, too.
- You (Judy) imply we should rely on radiative transfer instead. 8/13/11, 10:10 am. Yet, the uncertainty in RF is almost entirely due to radiative transfer assumptions. AR4, ¶2.3.1, p. 140.
- Your recommendation looks like throwing out the baby and keeping the bathwater.
- I endorse your notion to throw out back radiation, but don’t stop there. We should return to the lost art of estimating climate with a thermodynamic model. In that domain, heat is a flow variable, the greenhouse gases are a variable, passive resistance, and feedback can be modeled rationally and productively.
There may be more comments to be high-lighted, but the above capture some essence.
In any case, the net result appears to be that "back radiation" has now passed best-before-date and can be put into the wardrobe of pseudoscience together with phlogistons and luminiferous aether.
How much of CO2 alarmism based on back radiation, will have to go the same way?
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You seem to be the master on taking phrases out of context. Secondly, your arguments are only semantics. It doesn't matter what we call it - backradiation, DLR or black body radiation it all gives the same result - more CO2 results a warmer atmosphere.
SvaraRaderaYou also claim that DLR isnt mentioned in standard physics you are right. But black body radiation is and DLR is a RESULT of black body radiation of CO2 etc. That 'argument' of yours is purely semantics once again, nothing more.
The ONLY thing which is unclear is HOW MUCH more CO2 will warm after the feedbacks have occured, but what is almost certain is that it results at least SOME warming in the surface.
And even if the net result of adding more CO2 due to feedbacks was 0K (very strong negative feedback, possible but highly unlikely), it STILL doesn't falsify the so called greenhouse effect on earth (water wapor, other minor GHG's, clouds, etc...) nor the concept of DLR if that is what you like to call it.
Thank you for the compliment. I just quoted what people wrote. But it is not only semantics, as I have pointed out very clearly. Net flow or difference between two gross flows can make a big difference when it comes to perturbations, as it does. Since climate is not only radiation but also thermodynamics, considerations with radiation alone says nothing about reality.
SvaraRaderaRadiation IS part of thermodynamics. They are not separated in any way. In the end, matter, radiation and energy are all the same thing.
SvaraRaderaSecondly, ALL the energy earth loses to space, is by radiation. Not by conduction, not by convection. Those two things cannot ADD more heat, but only transfer it around inside the system and definitely cause some minor (maybe 1-2C) temperature changes.
For ADDING more heat to earth we need other sources of energy on top of the sun. If the IR opacity gets weaker, it also means the surface will receive more radiation, and more radiation means warmer temperatures. Just like a wooly hat will keep your head warmer in the cold winter days - even when the hat is actually colder than your hat. It seems like hats also violate the 2nd law :-) (well actually they dont, since the net flow is still from hotter to colder body... it gets just weaker, just like happens with CO2).
IF increasing DLR wouldn't cause any warming, it would violate the 1st law of thermodynamics. In the other hand, the DLR has been MEASURED even with a cheap IR-thermometer countless of times therefore there is no denying what has been observed.
What is certainly true, is that climate can vary even a lot without any change in CO2 or CH4. That is due the huge heat capacity of the oceans. Even a small change in ocean circulation patters can cause "warming" for decades, or mask the ghg-induced warming. But oceanic turbulences CANNOT explain the 33C hotter average surface temperature which also has been measured with several independent methods. It needs another 150W/m2 from other sources than the sun.
What I believe is that ocean oscillations have caused at least 50% of the recent warming therefore the alarmist case of 2-4K warming for doubling of CO2 does not add up. But even that is not an argument against he so called 'greenhouse effect.' You cannot deny it with 'right' mathematics appiled to totally wrong physics which is in contradiction to everything that has ever been measured.
Read my posts on fooling yourself by measuring DLR.
SvaraRaderaClaes: I'm impressed you noticed my comment at Climate Etc. I hope very much it didn't misrepresent your position too badly. I have no idea at all whether your ideas are right or not, but to judge from comparison of observations and theory there are questions in standard climate physics in need of far better explanation.
SvaraRaderaThe standard explanation doesn't - as far as I am aware - hinge around changes in the value of the lapse rate, but rather on the raising of the characteristic emission level. Therefore, one effective argument might be that increasing CO2 doesn't in fact raise the emission level. Another, that increasing temperatures somehow reduce the amount of energy input to the system. A third, that atmospheric effects introduce bends in the temperature profile such that increases aloft do not fully communicate to ground level. I'm unsure whether you are focusing on one of these arguments, or more likely on something else?
Whatever the answer, I agree that it is a good idea to think about the lapse rate. I also noticed the following deep discussion between Scienceofdoom, Arthur Smith, Leonard Weinstein and others:
http://scienceofdoom.com/2010/08/16/convection-venus-thought-experiments-and-tall-rooms-full-of-gas/
Not sure if you had noticed it before or if you find it interesting as well? One possible take-home from it is that persistence does pay!
Kindest regards,
Philip.
Thanks Philip. I agree that lapse rate is essential and will take a look at the discussion you suggest.
SvaraRaderaJuakola: When you write "the surface will receive more radiation, and more radiation means warmer temperatures" you show a complete misunderstanding of Claes' "Computational Blackbody Radiation." Whether or not the surface receives extra radiation from the atmosphere (as it may well do from warm air pockets which are warmer than layers below them) that radiation will have no warming effect if its frequency is below the cut-off frequency for the surface it meets.
SvaraRaderaThere is a new paper (Dec 2011) linked in the first paragraph of my site http://climate-change-theory.com which also supports one-way rather than two-way radiation calculations, as the latter lead to spurious absorption estimates.
Furthermore, I understand that experiments show that gases only start to absorb radiation when the source of such (spontaneous) radiation starts to get warmer than the gas - further support for Claes.
On Science of Doom (Backradiation - 3) you will find people like DeWitt Payne throwing in red herrings like lasers cutting hot metal, or microwave ovens warming food (actually the water within food) but these posts show a lack of understanding that Claes is only referring to spontaneous emission (based on temperature) rather than induced emission as in a laser. It is frequency that determines whether or not radiation is converted to thermal energy.
A perfect blackbody must be perfectly insulated from its surroundings. The whole "Earth plus atmosphere" system is such because it has space around it. Within the system, however, the internal surface/atmosphere interface is not insulated for it can lose thermal energy in ways other than radiation, including energy stored underground from day to night and from summer to winter. Neither is the atmosphere insulated as energy also transfers by molecular collision. So forget your -18 deg.C and all those SBL calculations as they are way out.
Claes is right. The IPCC is wrong. Temperature records in the Arctic (when analysed over the last 120 years or so) show absolutely no correlation with carbon dioxide levels - in the very place on Earth where it is supposed to be having greatest effect - see plots on my site. The climate is starting to level out and maybe cool until around 2028 due to natural cycles for which several plausible reasons have been postulated - see http://earth-climate.com
Claes: I have posted this on the comments board of the Wall Street Journal re their article about those scientists against AGW ...
SvaraRaderaMy understanding is that there are at least 31,000 scientists (9,000 of them with PhD’s) who have signed a similar statement.
However, I consider it unfortunate that the message has not yet “got out” that any radiation from cold layers of the atmosphere cannot have any effect on a (significantly) warmer surface – neither converting to thermal energy nor slowing its loss of such energy. This means that an atmospheric greenhouse effect is not caused by the assumed backradiation, whether or not it actually exists.
The IPCC has never produced empirical evidence that there is any warming effect from any backradiation. It does not, for example, melt frost that can lie in shady spots without melting all day long. And yet it is supposed to be about a quarter as powerful as direct sunlight at noon.
Last year Claes Johnson (a Professor of Applied Mathematics with many published papers to his name) published a note entitled “Computational Blackbody Radiation” in which he proved computationally that there is insufficient energy (as determined by frequency) in radiation from a cooler body for that radiation to be converted to thermal energy. The frequency of radiation from the cold atmosphere falls below a cut-off frequency which is proportional to the absolute temperature of the receiving body, that is the surface. When this is the case it will not warm the surface and it exits the surface with the same frequency (hence energy) and intensity that it arrived with, rather like having been reflected, though the process is different.
This is the real reason why we see absolutely no warming by carbon dioxide. All warming can be fully explained by natural cycles.
Furthermore, when short-term cycles are “corrected for” the longer-term (~1,000 year) cycle may be seen to be increasing at about 0.05 degrees C per decade, but its rate of increase is reducing, indicating a maximum within 200 years which would be only about 1 degree C warmer than at present. After that the world can expect about 500 years of cooling.
And there is nothing that mankind can do about either the warming rate or the cooling rate of the future.
Hi Claes, I am still looking for someone to do a real experiment that demonstrates that IR absorbing/emitting gases are able to warm (trap heat).
SvaraRaderaNot being able to find any proof, I thought of a simple real/thought experiment, which is posted on Judith Curry's site http://judithcurry.com/2012/05/30/science-is-not-about-certainty/#comment-205570.
What do you think?? Do you know any real physicists who can do real experiments and put the CO2 fiction to rest?
"Imagine an experiment in an IR reflective tube with sealed ends. Each end has a volume of CO2, separated by a vacuum contained by IR transparent material, which is able to move and separated by a removable IR reflector
[CO2|movable partition|vacuum|IR reflector|vacuum|movable partition|CO2]
Effectively we have a closed system which prevents heat transfer by conduction and convection. Radiation is blocked by the IR reflector. Pressure is able to equilibrate.
If we can add heat to one end, then remove the IR reflector, what will happen??
a. the warmer CO2 traps heat and the cooler CO2 does not warm.
b. the two volumes of CO2 will equalise in temperature by radiative transfer
c. the cooler CO2 radiates heat to the warmer CO2 which traps it
Surely we can do tis experiment in a lab?
"