Guest post by David Archibald
The greenhouse gasses keep the Earth 30° C warmer than it would otherwise be without them in the atmosphere, so instead of the average surface temperature being -15° C, it is 15° C. Carbon dioxide contributes 10% of the effect so that is 3° C. The pre-industrial level of carbon dioxide in the atmosphere was 280 ppm. So roughly, if the heating effect was a linear relationship, each 100 ppm contributes 1° C. With the atmospheric concentration rising by 2 ppm annually, it would go up by 100 ppm every 50 years and we would all fry as per the IPCC predictions.
But the relationship isn’t linear, it is logarithmic. In 2006, Willis Eschenbach posted this graph on Climate Audit showing the logarithmic heating effect of carbon dioxide relative to atmospheric concentration:
And this graphic of his shows carbon dioxide’s contribution to the whole greenhouse effect:
I recast Willis’ first graph as a bar chart to make the concept easier to understand to the layman:
Lo and behold, the first 20 ppm accounts for over half of the heating effect to the pre-industrial level of 280 ppm, by which time carbon dioxide is tuckered out as a greenhouse gas. One thing to bear in mind is that the atmospheric concentration of CO2 got down to 180 ppm during the glacial periods of the ice age the Earth is currently in (the Holocene is an interglacial in the ice age that started three million years ago).
Plant growth shuts down at 150 ppm, so the Earth was within 30 ppm of disaster. Terrestrial life came close to being wiped out by a lack of CO2 in the atmosphere. If plants were doing climate science instead of us humans, they would have a different opinion about what is a dangerous carbon dioxide level.
Some of the IPCC climate models predict that temperature will rise up to 6° C as a consequence of the doubling of the pre-industrial level of 280 ppm. So let’s add that to the graph above and see what it looks like:
The IPCC models water vapour-driven positive feedback as starting from the pre-industrial level. Somehow the carbon dioxide below the pre-industrial level does not cause this water vapour-driven positive feedback. If their water vapour feedback is a linear relationship with carbon dioxide, then we should have seen over 2° C of warming by now. We are told that the Earth warmed by 0.7° C over the 20th Century. Where I live – Perth, Western Australia – missed out on a lot of that warming.
Nothing happened up to the Great Pacific Climate Shift of 1976, which gave us a 0.4° warming, and it has been flat for the last four decades.
Let’s see what the IPCC model warming looks like when it is plotted as a cumulative bar graph:
The natural heating effect of carbon dioxide is the blue bars and the IPCC projected anthropogenic effect is the red bars. Each 20 ppm increment above 280 ppm provides about 0.03° C of naturally occurring warming and 0.43° C of anthropogenic warming. That is a multiplier effect of over thirteen times. This is the leap of faith required to believe in global warming.
The whole AGW belief system is based upon positive water vapour feedback starting from the pre-industrial level of 280 ppm and not before. To paraphrase George Orwell, anthropogenic carbon dioxide molecules are more equal than the naturally occurring ones. Much, much more equal.
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well, I am also with Larry here, and I must add that up to now nobody has been able to actually show me from a decent experiment (which btw must involve actual sunshine and earthshine – not just a simple heat retention experiment ) that CO2 is a greenhouse gas. By definition: a greenhouse gas: the nett effect must be warming. The warming must come from the re-radiation of earthshine in the 14-15 um range. But CO2 has a number of absorptions in the 0-5 um range. So CO2 also re-radiates sunshine which causes cooling. They only recently discovered that CO2 also has absorptions in the UV range, so I donot think that we ever have done any decent testing on the whole spectrum that would involve what I am thinking of. I suspect that what we will find if we could construct such an experiment, is that it is pretty much evens with the cooling and warming of CO2 – in other words the net effect in W/m3 CO2 [0.04%] /24hours is close to zero.
This is based on the fallacious saturation argument isn’t it? Downward forcing becomes maximized because the all earth’s IR is absorbed by GHGs. But that ignores the fact that the GHGs themselves re-emit the IR which causes the whole atmosphere to warm. The saturation argument is how your transposed from your first figure showing an increase in forcing, to the second one showing almost no change in forcing.
dr.bill (02:47:03) :
Sorry about the formatting in the previous note. It seems that we can’t use the full set of HTML tags (notably sub- and super-scripts).
Don’t apologize. I think your “equation formatting” is pretty good. I didn’t even try to put my arguments in equation form and it made my post inordinately long.
We know that slavishly reducing the CO2 amount from 388 parts per million is not necessary and wrong and AGW is a hoax.
But a question:
What level of CO2 would be too high?
1500 parts per million?
500 parts per million?
2500 parts per million?
Higher than 2500 parts per million?
This seems to be the central question that has failed to be consistently addressed, so far.
I don’t know the answer, but this seems to be the direction one should head in to get ahead of the curve and address CO2 levels in a meaningful way.
My suspicion is that the acceptable level is higher rather than lower, but there must be a level, parts per million of CO2, that would constitute an upper limit.
Any ideas?
If there was no atmospheric circulation, the so-called greenhouse effect would make the Earth’s atmosphere ~140C warmer than it currently is.
Since, we know that the net “greenhouse” effect is only ~30C of warming… The net atmospheric feedbacks are strongly negative.
We have a fairly good idea of how much the Earth has warmed over the last 150 years (~0.7C)… We have fairly good reason to say that CO2 levels have climbed by ~100ppmv over the last 150 years. If we ascribe all of the warming to increased CO2, we can calculate that the maximum possible greenhouse warming that could result from a doubling of pre-industrial CO2 (275ppmv to 550ppmv) is a bit less than 2C.
Since we know that at least half of the warming over the last 150 years is due to solar variation and/or natural climate oscillations and we know that most of the other half is due to uncorrected UHI, human error and fraud… We can conclude that almost none of the warming over the last 150 years is the result of the 100ppmv increase in atmospheric CO2. Therefore, even less than almost none of the warming that may occur along with the next 100ppmv increment of CO2 will have been caused by the CO2.
Hi James. Just like too high sugar intake, CO2 can get dangerous if it reaches about 8-10% in your direct surroundings due to dilution of oxygen intake,. (MAK-value= 9000 mg/m3). However, the books say that only at 20-30 % it becomes lethal. Your body is used to absorb CO2 (think of cooldrinks).
Some (work) places have set a level of ca. 1% (1000 ppm) as a save working level.
We know that during the carniferous period CO2 ran into the thousands of ppm causing tremendous growth. So let us stick to 1 – 2 % as safe.. I do believe that more (than 400) rather than less is better i.e. if it can be proved that CO2 is not or not much of a greenhouse gas. See my comment at 7:29. CO2 and water vapor are sort of like your father and mother. More CO2 will stimulate growth – better crops and more forests.
Reed Coray (23:24:04) :
Phil (17:44:07)
“No, the critical flaw with your approach is that the frequency range of the insolation is not the same as the frequency range of the emission. Therefore it is quite acceptable to use an absorptivity of 0.7 and an emissivity of 1 (the correct values).”
Phil, I believe you are wrong. The spectral shape of radiation emitted from a black body surface at a temperature “T” degrees Kelvin obeys Planck’s law. By integrating Planck’s law over frequencies from zero to infinity, one obtains a total emitted power that is proportional to “T^4″. In general, if either (a) the emitted spectral shape does not obey Planck’s law, or (b) the integration is not over the interval zero to infinity, the total emitter power is no longer proportional to “T^4″. Thus, to use the equation for total emitted power: Total Power = “a” * “sigma” * “area” * “T^4″. where “a” is the emissivity and “sigma” is the Stefan-Boltzmann constant, the spectral shape of the emitted power must obey Planck’s Law.
Which is fine for the emission from the Earth which occurs above 5μm with an emissivity of ~1, if it emitted any in the visible around 0.5μm then you’d have to take into account the lower value of ε(ν). The insolation spectra of the Earth and its emission spectra are over different wavelength ranges which have different emissivities.
See here for a good description:
http://en.wikipedia.org/wiki/Kirchhoff's_law_of_thermal_radiation
You should be able to find it in any undergraduate general physics text.
In order to determine the average absorptivity of the Earth you’d integrate over all frequencies:
∫A(ν)Isun(ν)dν/∫Isun(ν)dν
Similarly for the Earth’s emissivity:
∫ε(ν)Iearth(ν)dν/∫Iearth(ν)dν
Where Isun is the emission spectrum of the sun and Iearth is the emission spectrum of the earth so while A(ν)=ε(ν) at any ν the averages are not the same because the spectra aren’t the same.
A C Osborn (03:35:46) :
It looks as if Phil is happy to ignore any and all Refutations of his beliefs and states his “Facts” with such conviction he must be a Climate Scientist.
I don’t talk about my ‘beliefs’ here only facts and they haven’t been refuted. Reed posted concerning emissivity/absorptivity (see above) while I was asleep (I am allowed to sleep aren’t I?) and I’ve responded to it
Sorry James. I made a simple 10x error. The safe working limit is 9000 mg/m3
= 9 g/m3. 1m3 air = ca. 1204g so 9/1204×100= 0,75%.
1000 ppm = 1 g/kg = 0.1%
So let us stick to 0.1%-0.2% CO2 as perfectly safe and promoting growth.
we are currently at close to 400 ppm = 0.04%
Gerard Harbison (09:06:07) :
Gail’s REPLY
You forgot the oceans. CO2 is more soluble in Cold water than in hot.
Peter Whale (09:14:11) :
Hi could someone tell me where I can find what the total Infra red energy coming to the Earth from outer space, which is of the frequency which can be absorbed or radiated back to earth or reflected back to space by co2?
Try these graphs.
The sun
http://www.globalwarmingart.com/wiki/File:Solar_Spectrum_png
http://www.freerepublic.com/~jim/
Sun and Earth
http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png
“Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics”
Gerhard Gerlich
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
Lots of interesting stuff even for those who will get lost in the maths. He thinks the “greenhouse effect” is mythical. If you look at nothing else, take a gander at the physicist’s summary. Apologies if posted earlier, but it’s new to me and may be to others.
“”” Reed Coray (23:24:04) :
Phil (17:44:07)
No, the critical flaw with your approach is that the frequency range of the insolation is not the same as the frequency range of the emission. Therefore it is quite acceptable to use an absorptivity of 0.7 and an emissivity of 1 (the correct values)…….
……
Since Kirchoff’s law requires that the emissivity and absorptivity be equal, a grey body that absorbs a fraction “a” of the power incident on the body, will radiate a fraction “a” of the power radiated by a black body at the same temperature…….
Sorry to butt in, but Kirchoff’s law which forces emissivity and absorptivity to be equal, is only true FOR A CLOSED SYSTEM THAT IS IN THERMAL EQUILIBRIUM. such as a cavity containing radiation. And in that case, it is a SPECTRAL equality as well; the two must be equal at each and every possible wavelength.
So kirchoff’s law does not apply to EM radiation or absorption on planet earth; ofr one thing, nobody even imagines that the LWIR emissivity matches the absorptivity for radiation in the solar spectrum range.
The whole idea of “flat plate” thermal solar energy collectors is based on the fact that the surfaces are prepared so that the solar spectrum spectral absorption coefficient, is very high (visually black), but the LWIR thermal emmissivity for the spectrum corresponding to the surface operating temperatuere is low; this can be achieved for exammple with broad band optical interference filter layers on the surface.
So Phil is in fact correct; and the total emittance and total absorptance can be different.
You have to really go out of your way to set up a condition in which Kirchoff’s Law DOES APPLY. So I’m with Phil.
Henry Pool (11:29:15) :
Thanks for the reply.
What your reply suggests in a rough and preliminary way is that at 388 parts per million we still have a large & substantial amount of cushion to work with before reaching an upper limit of CO2.
And, if CO2 parts per million has gone up 100 parts or so in the last 150 years, then at this juncture there is no looming crisis.
So, what we need is a refinement and increased resolution of that upper limit of CO2.
This would seem a more clear-cut objective than splitting hairs about whether 395 parts per million of CO2 or 360 parts per million CO2 makes a difference.
And, puts the endeavor more in a pure science realm as opposed to the current situation where political agendas have corrupted the science.
“”
James F. Evans (09:39:36) :
We know that slavishly reducing the CO2 amount from 388 parts per million is not necessary and wrong and AGW is a hoax.
But a question:
What level of CO2 would be too high?
1500 parts per million?
500 parts per million?
2500 parts per million?
“”
Seems like the extremely dangerous number is around 6% which corresponds to about 60000 ppm. That (I believe) is where it’s not possible for lungs to function anymore. That is quite a bit more than 6000 ppm which is around the upper limit that the Earth has apparently had in the distant past. Operating at 6000 ppm is probably around where there could be problems. It’s also probably beyond the point that could be attained by burning all fossil fuels over a period of time. I think some commercial greenhouses may operate in the range between 500 and 5000 ppm due to enhanced growing efficiency and where it is actually worth the cost of the equipment and co2 to do so.
George E. Smith (12:11:01) :
According to “Fundamentals of Statistical and Thermal Physics”, Reif, McGray-Hill, 1965, page 385
“A good emitter of radiation is also a good absorber of radiation, and vice versa. This is a qualitative statement of ‘Kirchoff’s law.’ Note that this statement refers only to properties of the body and is thus generally valid, even if the body is not in equilibrium; but we arrived at this conclusion by investigating the conditions which must be fulfilled to make the properties of the body consistent with a possible equilibrium situation.” (emphasis in the original).
I interpret the above statement to mean the emissivity and the absorptivity are equal even when a body is NOT IN THERMAL EQUILIBRIUM with its surroundings.
I believe I noted that the Earth’s emissivity (and hence absorptivity) might be a function of frequency. Assuming that is the case, the Earth’s emissivity/absorptivity at IR can and likely will be different from the Earth’s emissivity/absorptivity in the visible light portion of the electromagnetic spectrum. The problem I have is with the equation used to compute the power radiated by the Earth: emissivity times area times Stefan-Boltzmann constant times temperature in degrees Kelvin to the fourth power. I admit the equation is simplistic and doesn’t apply to the real world, but it is the formula used by people to justify the 255 degree temperature. For this equation to be used, the emissivity must be the same at all frequencies. The equation may be a reasonable approximation for Earth-like frequency-dependent emissivity and if someone can so demonstrate, then I’ll better understand the 255 degree number. However, I await that event.
Re: cba (Mar 9 06:52),
What I’m saying about tropopause warming is this. Surface warming is expected to lead to an increase in specific humidity. The reason is that there is a large reservoir of water at the site of warming which can evaporate.
At the tropopause there isn’t. Now it may happen that the surface warms also, and SH at the tropopause increases for that reason (water from the sea). But there’s no local source up there. And although WV is mixed, there’s no mechanism that would cause more of it to move to the tropopause in response to temperature there.
Re: davidmhoffer (Mar 9 07:07),
…daily cycle effect of vegetation completely invalidates the guy’s ability…
Yes, it does. Because the fluctuations that he’s seeing have nothing to do with global CO2. And there’s no reason to expect that they’ll average out to mean zero. If there are local CO2 sources, they’ll bias the measurement high, to an unpredictable extent.
Modern CO2 measurements taken far from sources do not show these fluctuations. They show steady behaviour, with a gradual increase, and a very small seasonal cycle.
Beck’s pre-1960 curves are quite different. There’s no reason to believe the world changed radically in 1960. The logical explanation is that if you sum a random collection of measurements with all sorts of local effects, you measure something quite different to what eg the Scripps sites are measuring now for global CO2.
Well at a pinch, I can only cite two references that I have here at my desk. The first is from:- “The Infra-Red Handbook.” Edited by William L. Wolfe, ( Profesor of Optical Sciences, University of Arizona, Consultant to Infra-red Inaformation Analysis (IRIA) Center, Environmental Research Institute of Michigan; and George J. Zissis Director Emeritus of IRIA.
The Handbook was prepared for the Office of Naval Research, Department of the Navy, Washington DC. I have the 1985 Revised Edition.
ISBN: 0-9603590-1-X
On page i-30 (I’ll have to spell out the math.
“1.3.3 Kirchoff’s Law. By considering two bodies IN THERMAL EQUILIBRIUM, one a black body and one arbitrary, one can show that:-
(alpha) = Integral, 0-infinity[alpha(lambda).dlambda] =
(epsilon)= integral, 0-infinity[epsilon(lambda).dlambda)
It can also be shown that alpha(lambda)=epsilon(lambda)
where the temperature of both bodies is the same and the spectral region of consideration is the same for both alpha and epsilon. Since these depend upon the total power law, they also depend on THERMAL EQUILIBRIUM.
Emphasis added by me, alpha is absorptance, and epsilon is emittance.
My second reference is the Handbook of Optics sponsored by the Optical Society of America (I’m a regular member), edited by Walter G Driscoll and William Vaughan. Chapter 1 on Radiometry and Photomoetry, edited by Jay F. Snell, Tektronix, Beaverton Or.
Page 1-22, Kirchoff’sLaw.
28 Kirchoff’s Law is a consequence of the necessary existence of an energy balance between emission and absorption for a body IN AN ISOTHERMAL BLACK ENCLOSURE AND IN TEMPERATURE EQUILIBRIUM WITH THE ENCLOSURE. Since the radiation field in such an enclosure is isotropic, the directional spectral emissivity and the directional spectral absorptance of the body are equal.
“Born and Wolfe” as in Max Born and Emile Wolfe, simply mentions Kirchoff’s Law (among many of his laws) but does not deal with it, since their textbook is mostly involved with the electro-magnetic theory of Optics, rather than the thermodynamic theory. The theories of propagation, diffraction, interference etc, which are electromagnetif field phenonena; are unrelated to the thermodynamic principles of radiative energy.
Note that the second citation, is even more restrictive than the first, in demanding that the enclosure be ISOTHERMAL in addition to demanding equilibrium.
Warren Smith has an excellent treatment of Black Body Radiation; but once again , from a diffrerent point of view, than thermodynamics, so although he has the best treatment of the Planck Law and related laws; like Born and Wolfe, he does not deal with Kirchoff’s Law. Before his relatively recent death, Warren Smith was with Infra-red Industries in Santa Barbara California; and along with Rudolph Kinglake of Eastman Kodak, was the Dean of Optics in America.
The proof of Kirchoff’s law, follows the principle of showing a violation of the second law of thermodynamics, by creating a higher temperature in a receiving body, than a source body, if the equality conditions aren’t met.
Like I said; you have to really go out of your way to construct a case where Kirchoff’s law applies (in practice).
But I’m happy to entertain any other inputs.
Bearing in mind any of the above that one might consider relevent; I should simply mention that in the question of earth cl;imate system from a radiative balance point of view; the major SOURCE of EM radiation energy, is the sun at a not too isothermal temperature of about 6000 K; while the “Sink” body, the earth is at about 288 K on average, but about 183, to 333 K total temperature range; neither isothermal, nor in thermal equilibrium with the sun.
Besides the earth rotates every 24 hours, so there is no way it could be in thermal equilibrium.
I still support Phil’s assertion that the absorptance (alpha) and the emittance (epsilon) can be different; especially for totally different spectral ranges.
“”” Reed Coray (13:47:29) :
George E. Smith (12:11:01) :
According to “Fundamentals of Statistical and Thermal Physics”, Reif, McGray-Hill, 1965, page 385
“A good emitter of radiation is also a good absorber of radiation, and vice versa. “””
And if the latter statement was correct, then spectrally selective solar thermal energy collection panels simply would not work; providing experimental proof of the falsity of that assertion.
In my humble view, this is the rock that breaks the CO2 driven AGW hypothesis. It seems completely obvious that effect of each added parcel of CO2 is almost completely masked by the near 100% IR absorption bands from the CO2 that is already in the atmosphere.
In my view, the AGW proponents would have to present *hard* scientific evidence showing that this logarithmically diminishing effect of CO2 was not true if they wanted to re-establish their case.
I think one might easily demonstrate this CO2 masking by using a couple of overlay transparencies – one showing the pre-industrial absorption bands and an overlay showing the effect of the CO2 added in the modern era.
Phil (8Mar10, 20:24:16) said:
“Do the math, radiation is the dominant heat loss route from the surface…”
I will use the figure in FAQ 1.1, Chapter 1, WG1, IPCC AR4 (2007), which is from Kiehl & Trenberth (1997).
The energy fluxes from the surface are (all figures are in W/m^2):
Radiation: 390-324 (back radiation) = 66
Conduction: 24
Latent Heat (in water vapour): 78
So, having done the maths (in my country we do it in the plural), the dominant heat loss route from the surface is in fact water vapour.
Of the Surface Radiation, only 26W/m^2 is absorbed by the atmosphere (the other 40w/m^2 goes straight through out to Space).
So as far as the atmosphere is concerned, it gets its energy from the surface in the following proportions:
Latent Heat: Three Fifths
Conduction: One Fifth
Radiation: One Fifth
When the surface warms, the Radiation proportion decreases and the Latent Heat proportion increases (this will be true if evaporation increases, which is uncontroversial).
The levels at which these fluxes enter the atmosphere are different:
Conduction (one fifth) at the base of the column.
Radiation (one fifth) into the lowest 500m or so
Latent Heat (three fifths) into the clouds.
So a heating of the surface changes the distribution of flux into the atmosphere from low down to higher up.
Ken Roberts (07:41:04) : edit
I wish people could get past this one. There are a number of CO2 measuring stations around the planet. All of them tell the same story.
Yes, Mauna Loa is an active volcano, I used to be able to see it from my house when I lived in Hawaii. However, it’s a great place to take CO2 measurements. They are taken at night, when the air is descending from high altitude as part of the day/night sea breeze/land breeze cycle common to islands. This is air which has been way up high crossing the Pacific, and passes over very little land before being sampled. And true, sometimes the samples are contaminated by volcanic CO2.
Wikipedia is wrong when they say that the measurements are adjusted when this happens. They are not. It is immediately obvious when the air is contaminated with volcanic CO2, because as you might imagine the CO2 levels spike off the charts. These samples are not used for baseline CO2 measurements (although they are used to estimate the amount of CO2 being outgassed by the volcano). Since they take several measurements per night, this generally does not leave them without data. The volcanic CO2 is also usually near the ground, so the measurements are taken both at the ground and from tall towers as well. If these two agree and there is no unusual readings, they know they have measured good air.
So although as you might surmise I am a suspicious SOB who doesn’t believe anything related to climate science without a very hard look, I am satisfied that the data coming from Mauna Loa are valid and can be relied on. See this site for more information.
How do they know which country emits what?Can they measure the emissions from each country,or do they guess based on what each country does every year?