Estimated CO2 Warming Cut By 65%
Submitted by Doug L. Hoffman, Resilient Earth via ICECAP
Any competent researcher involved with the science behind climate change will admit that CO2 is far from the only influence on global climate. It has long been known that short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Though the IPCC and their fellow travelers have tried to place the blame for global warming on human CO2 emissions, decades of lies and erroneous predictions have discredited that notion. For anyone still clinging to the CO2 hypothesis, a short perspective article on the uncertainty surrounding climate change in Nature Geoscience has put paid to that notion. It states that not only did other factors account for 65% of the radiative forcing usually attributed to carbon dioxide, but that it is impossible to accurately determine climate sensitivity given the state of climate science.
In “Short-lived uncertainty?” Joyce E. Penner et al. note that several short-lived atmospheric pollutants – such as methane, tropospheric ozone precursors and black-carbon aerosols – contribute to atmospheric warming while others, particularly scattering aerosols, cool the climate. Figuring out exactly how great the impacts of these other forcings are can radically change the way historical climate change is interpreted. So great is the uncertainty that the IPCC’s future climate predictions, which are all based on biased assumptions about climate sensitivity, are most certainly untrustworthy. As stated in the article:
It is at present impossible to accurately determine climate sensitivity (defined as the equilibrium warming in response to a doubling of atmospheric carbon dioxide concentrations) from past records, partly because carbon dioxide and short-lived species have increased together over the industrial era. Warming over the past 100 years is consistent with high climate sensitivity to atmospheric carbon dioxide combined with a large cooling effect from short-lived aerosol pollutants, but it could equally be attributed to a low climate sensitivity coupled with a small effect from aerosols. These two possibilities lead to very different projections for future climate change.
All truthful climate researchers know these facts, yet publicly the party line is that catastrophic changes are in the offing and CO2 emissions are to blame. The perspective authors argue that only by significantly changing the amounts of these other pollutants and carefully measuring the impact on global climate over a period of several decades will science be able to figure out what is going on. “Following this strategy, we will then be able to disentangle the warming and cooling contributions from carbon dioxide and short-lived pollutants, hence placing much tighter constraints on climate sensitivity, and therefore on future climate projections,” they state. See chart below, enlarged here.
And they said it was all carbon dioxide’s fault.
Most of the factors under discussion have relatively short lifetimes in the atmosphere, several less than two months. We do not know how the relative influences of these various substances (referred to by climate scientists as “species”) may change in a warming climate. It is also not clear how to reduce short-lived species under present conditions but the uncertainties in atmospheric chemistry and physics must be resolved if Earth’s environmental system is to be understood. Again quoting from the paper:
Of the short-lived species, methane, tropospheric ozone and black carbon are key contributors to global warming, augmenting the radiative forcing of carbon dioxide by 65%. Others – such as sulphate, nitrate and organic aerosols – cause a negative radiative forcing, offsetting a fraction of the warming owing to carbon dioxide. Yet other short-lived species, such as nitrogen oxides, carbon monoxide and volatile organic compounds, can modify the abundance of both the climate-warming and climate-cooling compounds, and thereby affect climate change.
Quantifying the combined impact of short-lived species on Earth’s radiative forcing is complex. Short-lived pollutants – particularly those with an atmospheric lifetime of less than two months – tend to be poorly mixed, and concentrate close to their sources. This uneven distribution, combined with physical and chemical heterogeneities in the atmosphere, means that the impact of short-lived species on radiative forcing can vary by more than a factor of ten with location or time of emission. The situation is further complicated by nonlinear chemical reactions between short-lived species in polluted areas, as well as by the interactions of clouds with aerosols and ozone. These processes add further uncertainty to the estimates of radiative forcing.
Unfortunately, climate models neither accurately deal with local effects of these pollutants nor are the complex interactions among these substances understood. That not withstanding, the report is clear – CO2 does not account for even a majority of the warming seen over the past century. If other species accounted for 65% of historical warming that leaves only 35% for carbon dioxide. This, strangely enough, is in line with calculations based strictly on known atmospheric physics, calculations not biased by the IPCC’s hypothetical and bastardized “feedbacks.”
Of course, the real reason for the feedbacks was to allow almost all global warming to be attributed to CO2. This, in turn, would open the door for radical social and economic policies, allowing them to be enacted in the name of saving the world from global warming. The plain truth is that even climate scientists know that the IPCC case was a political witch’s brew concocted by UN bureaucrats, NGOs, grant money hungry scientists and fringe activists.
Now, after three decades of sturm und drang over climate policy, the truth has emerged – scientists have no idea of how Earth’s climate will change in the future because they don’t know why it changed in the past. Furthermore, it will take decades of additional study to gain a useful understand climate change. To do this, climate scientists will need further funding. Too bad the climate science community squandered any public trust it may have had by trying to frighten people with a lie.
Be safe, enjoy the interglacial and stay skeptical. Read full post here.
Icecap Note: Whatsmore, this totally ignores the other external and internal global factors like solar, ocean multidecadal cycles related to variations in the thermohaline circulation or ocean gyres.
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Here is the paper at Nature Geosciences:
Short-lived uncertainty?
Joyce E. Penner1, Michael J. Prather2, Ivar S. A. Isaksen3,4, Jan S. Fuglestvedt4, Zbigniew Klimont5 & David S. Stevenson6
- University of Michigan, Ann Arbor, Michigan 48109-2143, USA
- University of California, Irvine, California 92697, USA
- University of Oslo, PO Box 1022, Blindern, 0315 Oslo, Norway
- Center for International Climate and Environmental Research (CICERO) Oslo, PO Box 1129 Blindern, 0318 Oslo, Norway
- International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, 2361 Laxenburg, Austria
- School of Geosciences, The University of Edinburgh, Edinburgh EH9 3JN, UK.
Correspondence to: Joyce E. Penner1 e-mail: penner@umich.edu
Abstract
Short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Curbing their emissions and quantifying the forcing by all short-lived components could both mitigate climate change in the short term and help to refine projections of global warming.
Earth’s climate can only be stabilized by bringing carbon dioxide emissions under control in the twenty-first century. But rolling back anthropogenic emissions of several short-lived atmospheric pollutants that lead to warming — such as methane, tropospheric ozone precursors and black-carbon aerosols — could significantly reduce the rate of climate warming over the next few decades1, 2, 3.
EFS_Junior says:
“CO2 in the atmosphere has a half-life of a few hundred years (e. g. centuries).”
That statement is not true. On average, a CO2 molecule is re-absorbed by the oceans and biosphere in probably less than ten years, not “centuries.” That residence time has a direct bearing on the climate’s sensitivity to CO2: the faster a CO2 molecule is absorbed, the lower the sensitivity number.
Also, the IPCC’s models are abysmal. They can not produce accurate predictions. CO2 has an effect, but it is insignificant. That fact trumps any claim that we must spend $Trillions on a non-problem.
By trying to make 0.039% of the atmosphere the central culprit, and generally disregarding all the other factors, both known and unknown, which cause the planet to warm and freeze, the alarmist scientists and their political enablers have painted themselves into a corner. Now they can’t get out without messing up their CO2=CAGW conjecture.
Well it looks like I was wrong.
Carbon is forever;
http://www.nature.com/climate/2008/0812/full/climate.2008.122.html
REPLY: Forever? Yeah sure right whatever uh huh. This is nothing more than another tweaked model. Even worse, they reference “Tim Flannery” aka Mr. “drought down under that ain’t happening” in the references. Yeah that’s the ticket, reference an Australian mammalogist slash palaeontologist writer of a best seller fiction book for a modeling study. Such rubbish I’ve never seen. These guys are clueless. So are you.
But you’ll defend it because it fits your belief system. – Anthony
Has anyone ever seen the estimated value for the total amount of CO2 forcing that is currently happening?
I could really put such an estimate to good use. I am guessing that it is proposed by the warmist crowd to be 50-100 W/m2. I could really, really use a reference on this proposed total. Using their dF = 5.35 ln(C/Co) I can get a reasonable -42 W/m2 as CO2 gets into the ppb, but that isn’t really what I need.
A reference would be EPIC if you can find it. I am also asking the warmist sites if they can provide such info. I am so very curious about the answers I get on this.
Be Prepared!
John Kehr
LarryOldtimer says:
October 12, 2010 at 2:44 pm
We folks are totally wasting our treasure on computers and computer models which can’t and never will predict the future, instead of storing it up to when it will really be needed.
I would have thought that the relatively small erruption of the unpronouncable name volcano in Iceland would have taught “climate scientists” some simple lessons, but greed outpaces sanity every time. When the volcano Katla in Iceland erupts in a large way, which it will, perhaps enough people in Europe will die to make an impression on “scientists” who don’t seem to have learned much in the way of the basic fundamentals of chemistry and physics.
Bingo!
There’s a whole host of big erupters besides Katla, like Elbrus (which really concerns me) and the VEI-5+ companion to Pinatubo, Cerro Hudson in Chile. Just to name a few. We’ll be lucky to get out of this likely 30 year cooling that’s coming. It could get a lot worse.
RE: Gary Pearse: (October 13, 2010 at 1:50 pm)
“If half the radiation from the sun is IR, I don’t understand how this in itself doesn’t “saturate” atmospheric CO2 IR capture on the way in, causing the IR that is irradiated from the earth/sea surface largely to escape.”
That all depends on what you mean by ‘half.’ The solar energy output spectrum as nominally given by Planck’s law formula includes a factor (multiplier) proportional to the frequency cubed. The peak solar spectrum energy is around 0.5 microns. At the 15 micron, CO2 absorption/emission band, one would expect this factor to be 27,000 times less than the factor at peak solar output. I assume this is why Robert Clemenzi in his paper “How Greenhouse Gases Work” says that that CO2 can cool the atmosphere at the mesopause level, 85 to 100 km up to around minus 100 deg C. Clemenzi attributes this to CO2 radiation finally becoming transparent to outer space at this level. The mesosphere is that level of the atmosphere just above the stratosphere.
He also states that the tropopause temperature, 11 to 17 km up, cools to around minus 60 deg C because radiation from H2O molecules can finally make it to outer space from this altitude as condensation prevents the uniform distribution of H2O in the atmosphere. From the standpoint of our general climate, I think the tropopause temperature is the very important because it sets an upper limit on how hot surface temperatures can be without adiabatic convection. It would seem that CO2 has little role in setting the temperature of this natural thermostat.
Mr. Watts, you are misleading everyone here.
First of all: this is not a “study”. It is a “commentary”. Download the pdf and look at it: nothing has been “studied” at all by these people.
Secondly: the arcticle starts off with saying: “Earth’s climate can only be stabilized by bringing carbon dioxide emissions under control in the twenty-first century.” .
So, since you put value on some numbers mentioned in the article, I guess you put equal value to this first statement as well? Or not, secretly? Since in your text, you use the article to ‘prove’ the *exact oppposite* of the statement I quote above. Ever heard of ‘cherry-picking’ mr. Watts?
Thirdly: ‘CO2 warming cut by 65%’, the title of your blog post. This statement is just a hundred percent false and incorrect. The article cuts nothing off CO2 warming, you just took a percentage you liked from the text, completely turned the whole context around and there you are. With my congratulations.
Smokey says:
October 13, 2010 at 5:35 pm
“EFS_Junior says:
“CO2 in the atmosphere has a half-life of a few hundred years (e. g. centuries).”
“That statement is not true. On average, a CO2 molecule is re-absorbed by the oceans and biosphere in probably less than ten years, not “centuries.” That residence time has a direct bearing on the climate’s sensitivity to CO2: the faster a CO2 molecule is absorbed, the lower the sensitivity number….””
Although partly true, your reply is just wrong enough to be very misleading. Your link (to a source I dare not mention the name of) compares apples and oranges. The IPCC actually agrees that the average time spent in the atmosphere by a CO2 molecule is about 4 years. CO2 is constantly being exchanged with the biosphere and particularly the upper ocean. Although a lot of it passes in and out of the upper ocean the net flow (ocean absorption) is rather small because the upper ocean becomes more saturated. In the big picture the exchange rate between the upper ocean and the lower ocean which indeed is in the realm of centuries is more important to determining how fast the ocean can remove large quantities of carbon from our atmosphere.
See the definition of “lifetime” and the discussion of response time in the IPCC AR4 glossary. The significant term here is “adjustment time”(or “response time”) not “ lifetime” or “turnover time” (“residence time” on your graph). http://www.ipcc.ch/publications_and_data/ar4/wg1/en/annexessglossary-e-o.html
Gary Pearse says:
October 13, 2010 at 1:50 pm
“If half the radiation from the sun is IR, I don’t understand how this in itself doesn’t “saturate” atmospheric CO2 IR capture on the way in, causing the IR that is irradiated from the earth/sea surface largely to escape.”
GHGs don’t “saturate” in this way. The more IR (in the appropriate wavelengths) they absorb, the more they either reradiate or pass on as thermal energy (primarily to O2 and N2).
I suppose there may be some theoretical maximum where the atmosphere gets so warm that virtually all the IR energy absorbed is almost instantly reradiated, but even then only part of it would continue “out”, and I doubt we are even close to that point in the troposphere.
The political bandwagon may switch track within a couple of years, to global cooling. It will for sure need large intelligent PR efforts, but when that is done, in the late 2010 and 2020s a large part of young people is assumed to contribute to weaken the West economy. Everything’s fine! Wind power is still used to “not disrupt the climate”, where fossil fuel emissions is claimed to be responsible for periods of unprecedented cool temperatures.
Hoffman grossly mischaracterizes Penner’s paper, which can be found (without sensationalism) at: http://xweb.geos.ed.ac.uk/~dstevens/publications/penner_ngeo10.pdf
1) The paper doesn’t say anything like: “Estimated CO2 Warming Cut By 65%”; it says that short-lived GHGs “[augment] the radiative forcing of carbon dioxide by 65%”. This means that the short-lived GHGs contribute 39% of the positive radiative forcing and CO2 contributes 60%. (100% forcing from CO2 + 65% more from short-lived GHGs; 65%/165% = 39%.) This anthropogenic positive forcing is countered by negative forcing from short-lived aerosols.
2) NOTHING in the paper contradicts IPCC dogma: Penner says the warming associated with 2X CO2 could range from 2-5 degC, the IPCC usually says 1.5-4.5 degC. Penner is proposing that we reduce emission of short-term GHGs to mitigate short-term climate change and permit observations that will enable scientist to accurately determine how much warming will occur from 2XCO2.
IMO, Penner’s proposal seems ludicrous. a) In the SAR, the IPCC said that warming up to 2 degC could be a net benefit, so we certainly don’t need to “mitigate” whatever short-term climate change may be occurring right now. If things get desperate in the second half of the 21st century, we can try reducing short-live GHGs and/or increasing aerosols. b) Even if we could magically eliminate anthropogenic aerosols and short-lived GHG’s, it would be at least 30-50 years before we had a long enough temperature record to accurately determine the long-term rate of GHG-induced temperature change against the background of natural variability (1890’s warming, 1910’s stabilization, 1930’s warming, 1960’s cooling, 1980’s warming, 2000’s stabilization; not to mention the larger changes associated with the LIA and MWP). If CO2 were a real problem, definitive results of Penner’s experiment will arrive far to late to be of value.
Frank-
To Hoffman’s credit I see that *he* has updated his “Resilient Earth” site to bring his calculations into line with yours. (Points for him).
I still contend you are both wrong however. (Folks that have read my comments up to now can stop here; I am being redundant)
Penner cites:
6. Forster, P. et al. in IPCC Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 129–234 (Cambridge Univ. Press, 2007).
for the (original) “65%” number. Looking at the graph FAQ 2.1 fig 2: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html it would appear that the new “39%” is only accurate if one is talking about ONLY THE SUM OF THE ANTHROPOGENIC POSITIVE forcings. If one is actually referring to the effects “CO2” (*as the headline claims*), the real effect is 0.00%.
Frank, I agree with you that Penner’s proposal seems ludicrous, but I would still contend that it is a theoretical point still worth making. What’s 2C anyway? My house is more than a couple meters above sea level…
Thoughts?
I believe it is a mistake to get hung up on this notion of a saturation (of the CO2 absorption.
Suppose that there is sufficient CO2 to absorb every single photon having an energy in some spectral range; surely that could be said to be saturated. So what if we double the amount of CO2.
All that happens is that all those photons now get absorbed in an atmosphere layer about half as thick as previously. The warmed atmosphere ultimately radiates its own thermal spectrum; whcih should be near to the surface spectrum given approximately the same temepratures. That atmospheric thermal emission slits about half up and half down. So a higher layer also containing CO2 will now grab the same energy photons from that emission, and warm that air layer too; and that process will keep on going. So the process of a cascade of absorption; thermalization; thermal emission; and recapture simply replicates in thinner layers if more CO2 is added (or any other GHG.
So the saturation argument is a bit of a red herring; and not a good place to stand and defend. To the extent that this multiple cascaded capture process further delays the escape of LWIR radiation, then during daylight hours, that delayed escape simply results in more sunlight coming in and a slight increase in the Temperature to balance with the further delayed emission.
But it is all moot anyway; since the H2O cycle simply re-adjusts the amount of cloud coverage to compensate.
The sooner that climatists dispense with this concept of a “Climate Sensitivity”, and the unsupportyable notion that it is somehow a logarithmic function; even though we can’t peg down the slope of the best fit line to better than a 3:1 ratio; how can they continue to claim it is logarithmic when a simple linear fit works with equal uncertainty for its slope. I’m sure you could fit the same data to the function y = exp(-1/x^2); with some similar uncertainty of parameters.
The cognoscenti of course will recognise this function as similar to the tortoise and the hare “paradox”; only more so.
At x = 0, the function has zero value; and so does its derivative; and so does the second derivative. In fact every single derivative of the function is zero at x = 0.
So if we start off at zero, with zero velocity, and zero acceleration; and zero rate of increase of acceleration and so on; how the hell does the function ever get to any other value ? like 37% for x = 1 .
What amazes me about this story is just how many congratulatory posts there were before anyone realized that there was a basic arithmetic mistake in the commentary, and that the paper was NOT suggesting that the effect of CO2 had been reduced by 65%.
I really think everyone should be obliged to read the original paper before commenting, and should go for all the papers discussed.
Jimmi-
I’ve wondered about that too.
Another funny thing…Gary Pearce asked an interesting question above concerning the “saturation” of GHGs by solar IR. I am aware of 3 other folks that have addressed it, and of them (all of which gave learned sounding responses) none of them addressed the most basic error in Mr. Pearce’s understanding of the issue. They did not hesitate however spin their answers to imply some kind of problem with the conventional wisdom.
Hi You All
I think that the real problem that we have here is not understood. Everybody has always assumed that there must be some truth in S.Arrhenius postulation that CO2 is a GHG. But he did not know at that time that CO2 also causes cooling. He made the same mistake as what currently everyone makes in schools and colleges by doing that stupid test with 100% CO2 and a light bulb….
See also: http://letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
We first need to determine (from actual tests) whether the net effect of CO2 in the atmosphere is cooling or warming.
If you people want to see some more science, here it comes:
here is the famous paper that confirms to me that CO2 is (also) cooling the atmosphere by re-radiating sunshine:
http://www.iop.org/EJ/article/0004-637X/644/1/551/64090.web.pdf?request-id=76e1a830-4451-4c80-aa58-4728c1d646ec
they measured this radiation as it bounced back to earth from the moon. So the direction of this radiation was: sun-earth-moon-earth. Follow the green line (for CO2) in fig. 6, bottom. Note that it already starts at 1.2 um, then one peak at 1.4 um, then various peaks at 1.6 um and 3 big peaks at 2 um. You see these peaks all back in fig 6 top.
This paper here shows that there is absorption of CO2 at between 0.21 and 0.19 um (close to 202 nm):
http://www.nat.vu.nl/en/sec/atom/Publications/pdf/DUV-CO2.pdf
There are other papers that I can look for again that will show that there are also absorptions of CO2 at between 0.18 and 0.135 um and between 0.125 and 0.12 um.
We already know from the normal IR spectra that CO2 has big absorption between 4 and 5 um.
So, to sum it up, we know that CO2 has absorption in the 14-15 um range causing some warming (by re-radiating earthshine) but as shown and proved above it also has a number of absorptions in the 0-5 um range causing cooling (by re-radiating sunshine). This cooling happens at all levels where the sunshine hits on the carbon dioxide same as the earthshine. The way from the bottom to the top is the same as from top to the bottom.
So, my question is: how much cooling and how much warming is caused by the CO2? How was the experiment done to determine this and where are the test results? (I am afraid that simple heat retention testing will not work here, we have to use real sunshine and real earthshine to determine the effect in W/m3 [0.03%- 0.06%]CO2/m2/24hours). I am doubtful of just doing analysis (determining surface areas) of the spectral data, as some of the UV absorptions of CO2 have only been discovered recently. Also, I think the actual heat caused by the sun’s IR at 4-5 may be underestimated, e.g. the radiation of the sun between 4 and 5 may be only 1% or 2% but how many Watts does it cause? Here in Africa you can not stand in the sun for longer that 10 minutes, just because of the heat of the sun on your skin.
Anyway, with so much at stake, surely, you actually have to come up with some empirical testing?
If this research has not been done, why don’t we just sue the oil companies to do this?? It is their product afterall.
I am going to state it here quite categorically again that if no one has got these results, then how do we know for sure that CO2 is a greenhouse gas? Maybe the cooling properties are equal to the warming properties. In fact, I suspect that it is indeed pretty much evens between the cooling and warming of CO2 in the atmosphere.
Henry P,
Yes of course CO2 and other gases are cooling as well as warming i.e they emit infra-red as well as absorbing it. In fact the net effect over the whole of the earth’s atmosphere must be zero (assuming the atmosphere is in equilibrium – at the moment it is probably slightly out of equilibrium). The reason for this is that all of the sun’s energy which falls on the Earth must eventually leave again – if it did not we would have fried long ago. The only way the energy can leave is by radiation, and the molecules which radiate in the infra red are the same as those that absorb i.e. the GHG’s. However you are not correct that the absorption and emission is the same at all parts of the atmosphere – in the lower part some of the absorbed energy is passed to other molecules, N2 and O2 mainly, by collisions, where it is held for a while i.e they get warmer. In the upper part of the atmosphere where the density is lower and collisions between molecules are are rarer, then re-radiation (emission) dominates and the energy passes out of the atmosphere.
Jimmi said
“However you are not correct that the absorption and emission is the same at all parts of the atmosphere”
Hi Jimmi
I did not exactly say that. I am saying that the path for earthshine to get from the bottom to the top is the same as for sunshine to get from the top to the bottom.
Light has the same properties, no matter what the wavelength, and it moves in straight lines.
Jimmi says: i.e they emit infra-red as well as absorbing it.
Henry@Jimmi
Remember: it is not only infra red I was talking about here. Look carefully at my post again. Ozone blocks a lot of UV light and without that earth would be lot warmer because the intensity of the sun in the UV is very high. CO2 also absorbs in the UV at a few places meaning it blocks some UV here. It also absorbs in the near infra red and infra red meaning it blocks the sunshine there as well. (some people prefer the term “re-radiated” instead of “block”, you can fill in what you like, I don’t care much about that – the point is that you can understand and describe what is happening if you look at that radiation coming back from the moon.)
When we talk of CO2 warming or cooling, I think we should be specific about the primary site where these comments apply. I think it is fair to say that CO2 can only have a direct cooling effect when CO2 molecules can leave the planet without further absorption.
According to Robert Clemenzi in his article “How Greenhouse Gases Work” and other sources I have checked, CO2 appears have a primary cooling effect above the stratosphere in that portion of the Earth’s atmosphere known as the mesosphere. Since CO2 is the best absorber of its own radiation, those photons emitted from CO2 will only heat the surrounding atmosphere at levels below the mesosphere.
According to Clemenzi, the troposphere is cooled by photons radiated from H20 which can escape the Earth’s atmosphere at the tropopause level and thus allow the tropopause to cool to minus sixty degrees C. I suspect that the cooling capacity of H2O at the tropopause may, by convection, offset surface heat trapping by CO2.
Clemenzi also points out that upper air temperature measurements indicate that close to 100 percent of all surface heat that ever will be absorbed by the atmosphere is, in fact, absorbed in the first 800 meters, as temperatures above this level do not change from day to night. (In calm weather)
“How Greenhouse Gases Work”
http://mc-computing.com/qs/Global_Warming/EPA_Comments/TheGreenhouseEffect.doc
Hi Spector
Give me some time to study this paper.
But have you understood what I said in my previous posts and here:
http://wattsupwiththat.com/2010/10/12/peer-reviewed-study-co2-warming-effect-cut-by-65-climate-sensitivity-impossible-to-accurately-determine/#comment-508922
??
Essentially I am saying that this cooling is caused by the CO2 blocking or re-radiating or bending away (some) radiation that otherwise would have hit on our heads. Hence we can measure as it bounces back to us from the moon. So, this cooling is caused by the same principle that applies to the greenhouse effect, i.e. this is the trapping of heat on earth when earthshine of wavelength 14-15 is deflected (or re-radiated) back to earth…
RE :Spectors: (October 17, 2010 at 7:03 am )
“When we talk of CO2 warming or cooling, I think we should be specific about the primary site where these comments apply. I think it is fair to say that CO2 can only have a direct cooling effect when CO2 molecules can leave the planet without further absorption.”
Correction: “when photons emitted by CO2 molecules can leave the planet without further absorption”
To answer Henry P, the effect of CO2 on incoming solar radiation is very small. It is a distant fourth place behind ozone, aerosols and water vapor, even if doubled, and these other effects are, for sure, taken into account. Even what effect it has is absorption leading to warming of the atmosphere, at the expense of cooling the surface.
Henry-
I think you are forgetting that GHGs also reemit IR photons that are leaving the earth. Since there is more IR trying to leave the earth than trying to get in (visible light is converted to IR) the net effect is to increase the IR that hits your head. Specter is right that the net cooling effect takes place in the upper stratosphere and above.
Henry@jim D
I believe you. But how much cooling is it (in W/m2/m3 {0.03-0.06 CO2} /24hrs)? And how does it compare with the warming of CO2 (by trapping earthshine 14-15 um)?
Same dimensions please. Actual test results please. No more “calculations” or models.
Now if we knew that, I suppose i would not be here trying to find out if anyone knows…
Henry@Spector
No doubt the study from Robert Clemenzi brings some valid points that I have not considered before. He does mention the problem of more water vapor, which I have also identified as a major cause for global warming (if this is or becomes a problem).
e.g.
http://wattsupwiththat.com/2010/10/14/dammed-if-you-do-dammed-if-you-dont/#comment-507090
As far as CO2 is concerned, I always thought that we must keep it simple and that we must try to measure the radiation (from earth) being trapped and the radiation (from the sun) being deflected to outer space and compare the results. I was hoping that we could do some reasonable measurements of this from above earth with satellites.
By measuring on top of a volcano (where the CO2 might be a bit higher) we could compare the results at slightly differing CO2 concentrations and so determine if there really is a warming or cooling effect caused by CO2.
I think Robert forgot to take a careful look at the difference between the incoming radiation (above the atmosphere) and what we measure at sea level (non-cloudy day)
The observation I made is that the ozone cuts away a large portion of the incoming sunshine, where the sun’s intensity is at its highest. I estimate that at least ca. 15% of the surface under curve is being cut away by the ozone.
Lower ozone (as in the past, before CFC’s were banned) would therefore cause a bigger ozone hole, which in my opinion would lead to a significant portion of UV reaching earth, which then has to leave here as radiation of higher wavelengths. So that must cause warming. The opposite, i.e. increasing ozone, as observed in the past 10 years, must then lead to cooling. Because of the % of radiation involved (if you look at those graphs of incoming solar radiation), I actually suspected that this may become a real problem, if the ozone gets too much.
In Robert’s postulation about the ozone, UV is being converted by the ozone to IR heat in the top layers of the atmosphere, and this heat is transported by CO2 to the tropopause.
It seems like there is no room for a bigger or smaller ozone hole due to less or more ozone, causing respectively either more or less UV reaching earth.
I am not sure about that. I think this is not following the principles of light. Light has to keep moving. It cannot stand still to convert to heat. My idea has always been:
light hits on the molecule from a certain direction (either sun or earth), is absorbed at certain wavelengths until filled (if the spectra of the molecule shows absorptions or absorptive regions), and is then re-emitted in all directions, including (50 -62,5%) back in the direction where it came from. So once filled it seems to me the molecule acts like a little round mirror, at that specific wavelength where it absorbs. This is what I see is happening. This is why we can measure the CO2 peaks of photons as it bounces back from the moon. (the path of that radiation was: sun-earth-moon-earth)
Eitherway, we need to find some measured proofs.