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And a spoof headline, because I am not showing or linking an experiment, but asking for one. Various people have purported to show GHE working in the lab, but I've never been convinced by their conditions or the scope of the experiment. CO2 in bottles just won't cut it.
So, the challenge is, how would YOU posit an experiment to show CO2 'greenhouse' warming in a lab? And I mean warming of the 'surface' by back-radiation, not warming of a gas in a bottle with fixed volume.
And the second challenge, how would you proceed to demonstrate the same thing happening outside the lab in the real world?
Don't bother to re-expound the theory or put up a new one, that is not relevant to this post. Propose a test, have it web-reviewed here, and we'll see whether we can get it done.
Oh, cheaper the better, of course, but don't let that hold you back. And if you are an ACTUAL physicist with access to a lab and students and gear, I will be expecting you to go all the way.
If you are an actual climatologist working on the stuff, as I know some of you are, that goes double.
Let me know when you get an answer, rhoda.I've been asking for empirical evidence that CO2 heats the climate for about the last 12 years. I haven't had an answer that goes even 10% of the way to providing a credible explanation.
"Don't bother to re-expound the theory or put up a new one, that is not relevant to this post. Propose a test, have it web-reviewed here, and we'll see whether we can get it done"
Jeez I thought Mrs Geronimo was formidable, but I believe I've found her soulmate.
I don't think you'll get any answers, but you'll probably be bombarded with irrelevant citations from BBD. That's if SkS have them. Look out for the Harries paper which is the darling of the warmist because it shows energy absorption in the 4 and 15 micron ranges increasing, while conveniently forgetting to tell us that the total energy retained is miniscule compared to the total OLR.
Good luck rhoda and do be kind to BBD, you ran rings round him last time with that "Oxfordshire housewife" stuff, s/he may be more careful this time, but I doubt it, there's an inbuilt feeling of superiority that makes him/her unable to stop inundating us with "peer reviewed" SkS sourced papers.
Two vessels filled with 1) higher concentration of CO2 2) normal air.
In the centre of each vessel suspended by wires is a metal sphere with attached 'equatorial' resistance heater, and 180 deg away the other side a thermocoulpe.
The sphere's a heated to a set stable temperature (as monitored by the thermocouple) then the heater is swithed off and the temperature is monitored every second while the spheres cool.
When the experiment is finished the vessels are flushed and the experiment is repeated with the gasses swapped.
If there is any 'greenhouse' effect the sphere in the vessel with the CO2 will cool more slowly/ each shpere should cool more slowly with the CO2 concentration.
I'm not sure what the vessel should be, how big the sphere should be or what colour if should be finished (if at all).
A tall air filled clear cylinder with a low power [black?] heat pad at the base will emulate the atmosphere via convection currents keeping the monitored heat pad [earth's surface] at a steady temperature.
A heat exchanger at the top of the cylinder [peltier perhaps?] could emulate conditions at TOA by a steady removal of heat..
If the radiative physics brigade are right, the addition of a small amount of CO2 to the air within the cylinder should raise the steady state temperature of the heat pad by 'back radiation'
I think that any increase in temperature would be too small to measure, or it would have been proved beyond doubt long ago.
Convection and cloud cover win hands down regarding global temperature variations, although the underlying long term global lower tropospheric temperature relies on atmospheric pressure coupled with insolation. As per the research of Nikolov and Zeller.
Aug 17, 2012 at 3:59 AM | RKS>>>>>
We could also increase the CO2 concentration to 98%, as on Venus, and really prove how ridiculous the AGW nonsense really is.
Steps to maintain the gas pressure constant [emulating the atmosphere] should be taken, perhaps by studious venting with increased temperature and pressure, or providing expansion space.
Aug 17, 2012 at 4:22 AM | RKS>>>>>>
The AGW brigade claim that the global temperature is 33K higher than it would be if there was no CO2 present.
Let's modify our experiment by firstly measuring the heater temperature with a 100% nitrogen 'atmosphere'.
Then add say 1000ppm of CO2 to the gas and see if the heater temperature shoots up as they say it should.
Any competent climate scientist with the simplest of labs could, and should have conducted this simple test years ago.
To replicate the real atmosphere the vessel the experimental atmosphere is contained in has to allow for expansion and be contained itself within a vacuum.
Aug 17, 2012 at 4:46 AM | Breath of Fresh Air>>>>
I already outlined the requirement for gas expansion in my post of 4:22.
In order to allow convection currents, which are the main cooling agents on earth, I specified a peltier cooler at the top of the cylinder to emulate conditions at top of atmosphere. Proper convection requires a higher level cooling to maintain these currents.
A vacuum would be superfluous to the setup as the vacuum around Earth allows radiation to space from TOA which is, of course, emulated by the peltier cooler.
The setup is perfectly capable of displaying the relative differences [if any] in heater [surface] temperature for different concentrations of CO2 - especially between zero, 400ppm and 98% as on Venus.
Aug 17, 2012 at 3:59 AM | RKS>>>>
Having mused a little longer, I think the cylinder should be well insulated so that only the known effects of the heat pad, and the peltier cooler may be taken into account when evaluating measurements.
Surely it is not necessary to replicate the atmosphere but simply to demonstrate the effect of CO2? Also the heating must be IR not conduction and the vessel must be transparent to all IR wavelengths.
Surely the experiment outside the lab is happening as we blog? We are told that we continue to add CO2 to the atmosphere but it has not warmed for 15 years. This does not prove of itself that CO2 did not have a warming effect but it proves that CO2 is not dominant which is a start.
Aug 17, 2012 at 2:00 PM | Dung>>>>
I would have thought that replicating the atmosphere is the perfect test for the so called GH effect on the atmosphere.
If there is ANY back radiation due to added CO2 the heating pad will be hotter than before, and the energy required to cause this can be calculated.
The pad heats both by conduction, as on earth, and also by radiation.
The main cooling effect, as on earth, is convection, otherwise the pad would become unrealistically hot.
By this method we can control energy in and energy out, thus emulating energy flux both at the earth's surface and TOA.
You may have noticed I also proposed an 'atmosphere, of 98% CO2.
By using radiation alone you cannot replicate the conditions of our atmosphere so cannot measure if CO2 has any effect at all.
You would need to create a theoretical model based on your CO2 radiation experiments, which would not provide the empirical evidence Rhoda has requested.
Like me you have noticed the lack of heating in the atmosphere while CO2 levels continue to rise.
What's wrong with attempting to find empirical proof that CO2 is NOT the player the IPCC wishes us to believe is?
The 'AGW brigade' says the average surface temperature would be 33K lower if there were no greenhouse effect. That is the cumulative effect of absorption and reradiation of LW by *all GHGs* - including water vapour - not just CO2.
The AGW brigade claim that the global temperature is 33K higher than it would be if there was no CO2 present.The 'AGW brigade' says the average surface temperature would be 33K lower if there were no greenhouse effect. That is the cumulative effect of absorption and reradiation of LW by *all GHGs* - including water vapour - not just CO2.
Aug 17, 2012 at 8:03 PM | BBD>>>>
So what IS the contribution of CO2?
Is it measurable?
To keep the discussion on thread - what is your contribution to rhoda's task or do you just want to snipe from the sidelines?
If we want to verify the GHE then the experiment can only use IR because that is what the GHE is about hehe ^.^
Why dont you engage with Rhoda and answer her request?
Pointing out an error isn't 'sniping'. I was just trying to be helpful :-)
As for why not discuss Rhoda's request, I am a bit stuck. A vital aspect of the enhanced GHE is the increase in the altitude of effective emission. Quite how you mock up a working demo of the troposphere in your garden shed is, I'm not embarrassed to admit, beyond me.
I have to say that making impossible standards of evidence a condition for discussion/acceptance is as old as marriage though :-)
Aug 17, 2012 at 10:17 PM | BBD>>>>
Why bother with empirical data when speculation and best guess AGW hypotheses will do.
Aug 17, 2012 at 9:35 PM | Dung>>>>
The real world does not rely on IR 'back radiation' alone.
That effect should be measured alongside other major factors, although my setup could be used to measure the effect of 'back radiation' at the heat pad with a concentration of 100% CO2 compared to 100% nitrogen. Don't forget, even CO2 forms convection currents.
If GE is substantive my setup could show the difference in temperature at the heat pad [due to IR 'back radiation'] when CO2 is added to the gas mixture.
Knowing nothing about basic engineering BBD would not have the foggiest idea about how to replicate atmosphere in a basic setup. Other than reading god knows how many dodgy temperature statistics his science knowledge seems pretty weak as well.
Rhoda specified the GHE not the real world I hereby ban you from this thread for defying Rhoda!
Rhoda has pacified you hehe, she deserves a medal ^.^
Aug 17, 2012 at 11:26 PM | Dung>>>>
"So, the challenge is, how would YOU posit an experiment to show CO2 'greenhouse' warming in a lab? And I mean warming of the 'surface' by back-radiation, not warming of a gas in a bottle with fixed volume."
She wanted to see an experiment to show 'greenhouse' warming of the 'surface' - that's a pretty real world description and my proposal is meant to deal with just that.
Anyway, I've made my contribution - let's see if anyone else also has something positive to contribute to her thread. How about you Dung - what do you suggest as an experiment, it's seems from his post it's beyond BBD's intellectual capabilities to suggest an empirical way of proving his favourite hypothesis - AGW.
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