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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I do not accept that pre-industrial CO2 was 280 ppm.
That is another of the Climate-gate lies. Dr. Callendar and early CAGW proponent apparently successfully sold the idea that we could not trust the laboratory measurements of CO2 in the 1800s. Why? Because they measured atmospheric CO2 not 280 parts per million but varying over the place, from 330 -440 ppm, as Georg Beck showed.
The AGW Cassandras would rather read and realy on ice core proxies or chicken entrails, instead of of lab measurements. Scientists of two centuries ago conducted atmospheric composition studies and 93,000 measurements from lots of scientific teams publishing in scientific journals then, revealed that and also showed the rises due to the massive Tambora and Krakatoa volcanic eruptions.
We would be puzzled when comparing the Vostok ice core samples with their publications, were it not for Dr. Zbiegniew Jaworowski, the IPCC past ice core chairman, recognized for his world-leading ice core expertise. He said CO2 readily forms hydrates at modest pressure as in buried ice. It forms such hydrates and then stops at 280ppm, in the air bubbles in the ice.
He insisted that ice core readings had to be corrected for this effect to get a correct reading. But this is not done, and they have succeeded in convincing you that 280- ppm is the pre-industrial level, when it is not. The Moana Loa labs Loa-gate, created the image that the Vostok readings are accurate when they matched CO2 readings. But in reality, they merged data separated by 83 years to match and show a continuously rising curve. It is a pure scandal and bunk.
Reed Coray (15:25:22) :
A critical flaw with this approach is that for thermal radiation from “grey body” surfaces, the principle of detailed balance (which is a qualitative form of Kirchoff’s law) requires that the emissivity and the absorptivity of a surface be equal. Thus, it is inappropriate to simultaneously use an absorptivity of 0.7 and an emissivity of 1. When the preceding model is used with the single change that the average absorptivity equals the average emissivity, the Earth’s temperature is approximately 278 degrees K, not 255 degrees K; and provided the absorptivity is not zero, the temperature is independent of the absorptivity.
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).
George E. Smith (12:42:22)
I think that’s the reason why we stopped using plain air between the 2X4 walls and decided to encase the air in fibers for insulation.
It seems that about everyone knows that the “greenhouse gas hypothesis” should not be equated to what really happens in an actual greenhouse, because it ignores convection. Well, folks, the “atmospheric greenhouse gas hypothesis” suffers the same problem, IMHO.
Re: Bill Illis (Mar 8 17:11),
“If temperatures increase by 1.2C at the (former level of the) tropopause emission layer, water vapour will increase”
??? How? At the surface warming leads to more water because of evaporation from the surface. But what is the source up there?
Well, that explains why the poles are so warm …
Wait; maybe not. Just the converse (To paraphrase: ” It’s the LWIR, s***** ” ) …
The ‘convectionists’ need to explain this one outside of exalted convectionist doctrine.
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“”
Colin Davidson (17:09:44) :
The figure of 1DegC warming for a 3.5W/m^2 increase in Radiative Forcing (which the IPCC makes clear is a forcing at the Tropopause) is for the Tropopause area only…..
“”
At the tropopause (assuming std 1976 atm values), one sees 3.7w/m^2 decrease in transmitted IR from the surface. For the atmosphere, it seems that the actual average sensitivity is around 0.22 K rise per w/m^2 increase. For 3K that’s about 14 w/m^2 increase. THe number comes from the avg values associated with Earth – 33 K rise due to atmosphere, 288.2k avg surface T, 235w/m^2 average emission to balance the 235 avg incoming solar with an absorption of around 150 w/m^2 (which includes cloudy skies not just clear sky conditions). This also accommodates the avg contribution of convection.
for the co2 doubling, this is 3.7 w/m^2. Assuming a 5 K rise in column T, the absolute humidity should increase by 30% which corresponds to less than another 3.7 W/m^2 contribution to the needed forcing. At 0.22 sensitivity. we’ve got less than a 1.7 K rise in T which means the h2o vapor is contribution is way too small to generate anything close to what is needed. Consequently, we’re missing almost 3 1/2 deg. of the original 5k presumed temperature increase (for the h2o increase calculation).
What happens above the tropopause (and below) is also interesting. Increasing the absorption means increasing the emissivity. The atmosphere radiates more at the same temperature. By 70 to 100 km altitude, note also that the co2 doubling difference is back down to just over 2W/m^2 (or so I seem to recall at the moment). The lapse rate depends now upon the conservation of energy. Increases in ghgs mean increases in emissivity and hence a drop in T due to the need for energy balance.
JAE (12:41:13) :
If the GHG effect of CO2 is logarithmic, then so is it for HOH, yes? If so, then we are so “far-out” on the curve that any type of “water vapor feedback” is not possible. No?
No. A weak absorber (Freon in atmosphere) is ~linear (Beer’s Law), moderately strong (e.g. CO2) is ~log, and strong (e.g. CH4 or N2O) is ~ square root
“” Nick Stokes (19:08:37) :
Re: Bill Illis (Mar 8 17:11),
“If temperatures increase by 1.2C at the (former level of the) tropopause emission layer, water vapour will increase”
??? How? At the surface warming leads to more water because of evaporation from the surface. But what is the source up there?
“”
gee nick – better be careful or you’ll become a skeptic.
h2o vapor gets there by the usual method. it’s a lighter weight molecule so tends to rise, it absorbs solar energy so it tends to form a hot air bubble (skinless hot air balloon). Ultimately, despite carrying copious amounts of energy aloft, it cools off and drops the h2o vapor out of the air parcel to bring it into line with the humidity for the upper temperatures, dropping solid or liquid h2o and permitting the cycle to continue carting up the heat of evaporation.
besides a lack of h2o vapor upstairs leads to less ‘trapping’
Bill Illis (17:11:20) :
The global warming theory does provide a number of testable hypothesis. Generally each component of the following assumptions can be tested. This may be a new explanation of global warming theory for some of you.
1) If CO2/GHGs double, there should be an increased forcing of 4.0 watts/metre2 at the tropopause emission layer which is now 255K or 240 watts/m2 (on average 5 kms up, not the surface);
No, the forcing should stay the same at that point but the layer altitude will change.
Great comment Bill. The thread has turned itself into a pretzel of algorithms to determine exactly when the baby will poop. When it could be just as simple as checking the baby’s diaper using the good ol’ fashioned smell test.
The confirmation of general relativity had nothing to do with diffraction. Diffraction is an optical effect due to light’s wavelike behaviour when passing close to obstacles or through small gaps. The confirmation Wind Rider is discussing was a difference between the effects of gravitational attraction considered as a classical force on a moving projectile, namely the photon travelling at c (Newtonian physics) and that predicted if space were curved (from memory, the latter is something like twice the former, but don’t hold me to that).
No need to be insulting, especially as he is right and you are wrong. The OP talked about a range and speculated about “the whole curvet”, meaning outside the range. The fact is a 1/x curve is bounded and a log curve isn’t, making them fundamentally dissimilar, and the OP was talking about the entire range, not a narrow range in which the approximation is valid.
len (17:33:31) :
Sergey (09:37:55) :
“The very premise of this article that 30C increase in surface temperature is explained by greenhous effect is wrong. This difference is due to convection.”
Thank you. Convection trumps radiative effects in every complex system. Why the effect seen in the backwards derivation of the magical properties of CO2 I don’t know.
Do the math, radiation is the dominant heat loss route from the surface and the only heat loss route to space.
Considering the history and persistance of this line of reasoning I don’t blame David for putting forward this intellectual argument.
That’s something of an overstatement, the original posting is largely rubbish!
The forcing equation (apparently due to Willis E) is physically nonsense so anything derived from it is meaningless.
The graph with the red line going on to 6ºC is deception, superimposing a graph of ºC/doubling on a graph with an axis of ºC/20ppm, in reality the redline should increase to ~0.16ºC. Of course that ignores the fact that all the 6ºC is the top of the possible range (and isn’t all due to CO2 anyway).
And so on with more similar rubbish.
There is only one comment I haven’t made yet and that is given the logarithmic effect of CO2, I suppose if we remove it from the atmosphere its effect goes to infinity 😀 … so like many have noted here, until I see some empirical experiment that shows something interesting and not some assumption laden model based derivation disguised as an experiment … the CO2 effect is ZERO in my mind and simply does not exist. It is only a small part of layers of a mixed gases of certain densities of the layered fluids that blanket the surface of the Earth and the phenomena we are observing should be renamed the ‘Blanket Effect’.
CO2 represents the large majority of the permanently radiatively active gases in the atmosphere: CO2, 385ppm; CH4, 1.8ppm; N2O, 0.3ppm, i.e. about 99%.
Phil, in what sense are you using the word “permanent”? Do you mean that if you could name each of your lil’ CO2 molecules, you would find the same ones 10 years from now? Or do you mean that CO2 is a permanent gas, always present, even though individual molecules are re-absorbed into the Earth’s recycling system and then reappear sometime later? Isn’t that the case then with water vapor as well? Always present but always being recycled.
Phil. (20:24:16) :
CO2 represents the large majority of the permanently radiatively active gases in the atmosphere: CO2, 385ppm; CH4, 1.8ppm; N2O, 0.3ppm, i.e. about 99%.
False. H2O’s concentration is 30 times+ that of CO2, it is approximately equally radiatively active and uniquely able to condense, evaporate, convect, and even take solid form. Sorry, seems H2O is the 800 pound gorilla driving this GHG bus.
Everything about this material reeks of authoritative fraud. Greenhouse gasses do not add an iota of heat to the atmosphere, because the atmosphere is cooled by radiation which goes aroung them rather than through them, as demonstrated by Lindsen and Choi. Does a gate half open keep half of the sheep in? Blocking half of the wavelengths with greenhouse gasses does not keep half of the heat in the atmosphere.
Furthermore, the temperature of the atmosphere equillibrates with the rate of heat entering the planet from the sun and rate of heat leaving the planet. The equilibration temperature is totally independent of how heat enters the atmosphere. The heat enters the atmosphere about a hundred times faster through conduction and convection than through radiation. This is why cooling fans are used in electronics rather than relying upon radiation.
Gary Novak
http://www.nov55.com
Phil. (20:24:16) :
“CO2 represents the large majority of the permanently radiatively active gases in the atmosphere: CO2, 385ppm; CH4, 1.8ppm; N2O, 0.3ppm, i.e. about 99%.”
You seem to have left one rather significant component out of your calculation, namely H2O. The two papers I referenced in my comment from earlier today, which constitute most of scientific effort to actually quantify the contributions of the various “greenhouse gases, seem to indicate that, if CO2 is significant at all, its impact is likely limited to high latitudes in winter, polar environs, and possibly large desert areas. The common denominator being severely reduced H2O in the overlaying atmospheres. The Evans and Puckrin paper did claim to find an increase of 3.5W/m2 in their measured values versus preindustrial numbers they arrived at via a computer model, but their data tables indicate that the increase was almost entirely due to differences in readings from the Canadian winter. The values they derived for the summer season were in fact an exact match for what their model showed for preindustrial times. For the summer season the total downwelling longwave radiation was about 270W/m2 of which only 10.5W/m2 was attributable to CO2. Even the decidedly warmist authors were forced to comment on how elevated levels of H2O dramatically suppressed the CO2 response. At Tropical and Subtropical latitudes, where at least theoretically most of the extra evaporation needed to fuel the enhancement of the CO2 signal would occur, the predicted total of DWL is well above the level measured in the Canadian summer, which would indicate that in those environments CO2 would contribute only 2-3% of the “greenhouse effect” and that is for the total CO2 in the atmosphere. Any contribution from marginal increases in CO2 would be reduced proportionately.
Even if we stipulate to the observed 3.5W/m2 increase the paper claims, the fact that it was present for at most half the year, outside of the polar regions themselves, suggests that the effect hardly represents a global phenomenon. I can’t see many of the citizens of Canada, Siberia, or other northern climes jumping to embrace draconian measures to suppress CO2 emissions based on the notion that CO2 will make their winters less cold.
Re: cba (Mar 8 19:34),
“h2o vapor gets there by the usual method”
I kn ow how it gets there. The question is, why does tropopausal warming produce more of it? The air at that level is mostly pretty unsaturated – H2O is just another gas. Why would it move in response to a temperature differential?
Re: Pamela Gray (Mar 8 20:48), Re: wayne (Mar 8 21:11),
Phil, in what sense are you using the word “permanent”?
Phil’s usage is conventional, and indicated by the list he gave, It means gases that do not condense.
V
red432 (06:56:16) :
How does an individual assess competing claims on an issue of this complexity? You’ve got to have sympathy with the journalists who basically say “whoa, this biologist from Stanford must know what he’s talking about.” Of course with a little historical perspective we can remember that the entire academic world of Geology was wrong about plate tectonics a few decades ago… In the case of AGW even looking at temperatures doesn’t really help that much because “weather is not climate” and in my opinion even if it started decisively heating up again, that still wouldn’t indicate that greenhouse gases emitted by human activity had anything to do with it, necessarily. It’s a vexing question.
============
A few decades ago doctors were wrong about what caused ulcers. Does that mean I shouldn’t trust my doctor?
The old joke about asking two lawyers a question, and getting three answers, is equally true for scientists. This thread proves it.
@ur momisugly Pamela,
“Do you mean that if you could name each of your lil’ CO2 molecules, you would find the same ones 10 years from now?”
Yes, more or less. If you want more information on the longevity of CO2 in the atmosphere, have a read of this article in Nature:
http://www.nature.com/climate/2008/0812/full/climate.2008.122.html
Phil. (20:24:16) :
Do the math, radiation is the dominant heat loss route from the surface and the only heat loss route to space.
… CO2 represents the large majority of the permanently radiatively active gases in the atmosphere: CO2, 385ppm; CH4, 1.8ppm; N2O, 0.3ppm, i.e. about 99%.
More statements like ‘believe me because I said so’. Why is it that Einstein requires ‘gravitational lensing’ around the sun to be observed and documented while IPCC ‘climate science’ is funded by billions of dollars with gobblygook justification that can’t even be backed up with rhetorical certainty. It would be nice to be kissed before being … Arrhenius was the first great ‘Aesthetic Luddite Scientist’ and all I see here is more of the same.
I am going to search through the thread for a link to some real empirical data I know isn’t there. I’m sure I would have run into something in the past year but I just keep running into PUD … and it seems to be going septic.
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.
The emissivity of a surface is the ratio of the power radiated by that surface to the power radiated by a black body at the same temperature and same surface area. In general, emissivity can be a function of frequency. However, the common meaning of a “grey body” is that the emissivity is NOT a function of frequency. Thus, the spectral shape of the power radiated from a grey body also obeys Planck’s law, but with a constant scaling factor between 0 and 1 in the open interval sense. This implies that for a black body and a grey body at the same temperature and of equal surface area, the ratio of grey body emitted power to black body emitted power (the emissivity) is a constant for all frequency intervals. 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. This statement is true indendent of the frequency of the insolation power and independent of the temperature of the grey body.
Since the argument for the 255 degree K Earth surface temperature employs the T^4 law, you are caught between a rock and a hard place. You can use the T^4 law, but then the absorptivity and emissivity must be the same. Or you make the emissivity frequency dependent, but then you can’t use the T^4 law.