Guest Post by Ira Glickstein
Solar “light” radiation in = Earth “heat” radiation to Space out! That’s old news to those of us who understand all energy is fungible (may be converted to different forms of energy) and energy/mass is conserved (cannot be created nor destroyed).
My Visualizing series [Physical Analogy, Atmospheric Windows, Emission Spectra, and Molecules/Photons] has garnered almost 2000 comments, mostly positive. I’ve learned a lot from WUWT readers who know more than I do. However, some commenters seem to have been taken in by scientific-sounding objections to the basic science behind the Atmospheric “Greenhouse Effect”. Their objections seemed to add more heat than light to the discussion. This posting is designed to get back to basics and perhaps transform our heated arguments into more enlightened understanding :^)
As I’ve mentioned before, during my long career as a system engineer I’ve worked with many talented mathematical analysts who always provided precise results, mostly correct, but some precisely wrong, usually due to mistaken assumptions. I got into the habit of doing a “back of the envelope” calculation of my own as a “sanity check” on their results. If their results matched within reasonable limits, I accepted them. If not, I investigated further. In those days my analysis was really done using a slide rule and scrap paper, but I now use spreadsheets.
The graphic above is based on an excellent spreadsheet from http://serc.carleton.edu/files/introgeo/models/mathematical/examples/XLPlanck.xls. It uses Planck’s Law to calculate the black body radiation spectrum from the Sun, as observed at the top of the Earth’s Atmosphere. It also may be used to calculate the radiation spectrum from the Earth System (Atmosphere and Surface, see below for explanation) at any assumed temperature. (I will refer to this spreadsheet as “Carleton” in this posting.)
I modified the Carleton spreadsheet to compute the mean Solar radiation per square meter absorbed by the Earth System, which turns out to be 240 Watts/m^2. I then used the spreadsheet to determine the effective mean temperature of the Earth System that would emit an equal amount of energy to Space, and that turned out to be 255 Kelvins (-18ºC which is 1ºF).
Since the mean temperature at the surface of the Earth is 288 Kelvins (+15ºC which is 59ºF), that leaves 33 Kelvins (33ºC which is 58ºF) to be accounted for. Guess how we acount for it?
The yellow curve (above left) shows that Solar radiation is in a tall, narrow “shortwave” range, from about 0.1μm (microns, or millionths of a meter) to about 4μm, which we call ultra-violet, visual, and near-infrared. The vertical axis is Intensity of the radiation, measured in Watts/m^2/μm, and the horizontal axis is Wavelength, measured in μm. If you divide the area under the yellow curve into vertical strips, and add up the total area, you get 240 Watts/m^2.
Since we humans sense the visual portion of this radiation as “light”, that is the name we give it, and that has led to the false assumption that it contains no “heat” (or “thermal”) energy.
The violet curve (above right) shows that, assuming a mean temperature of 255 K, Earth System radiation to Space is in a squat, wide “longwave” range, from about 5μm to beyond 40μm, which we call mid- and far-infrared. If you divide the area under the violet curve into vertical strips, and add up the total area, you get the same 240 Watts/m^2 as is under the yellow curve.
DETAILED EXPLANATION
The graph on the left shows the actual observed Solar radiation spectrum (in red) as measured at the top of the Atmosphere. It is superimposed on a black body model (in blue) showing very good correlation. Thus, while the Sun is not exactly a black body, it is OK to assume it is for this type of “sanity check” exercise.
If you calculate the area under the curve you get about 1366 Watts/m^2. That means that a square meter of perfect black body material, held perpendicular to the Sun, would absorb 1366 Watts.
However, the Earth is not a perfect black body, neither is it a flat surface perpendicular to the Sun! So, to plot the yellow curve at the top of this posting, I had to adjust that value accordingly. There are two adjustments:
- The Earth may be approximated as a sphere, with the Sun shining on only half of it at any given time. The adjustment factor for this correction is 0.25.
- The albedo (reflectiveness) of the Earth system, primarily clouds and light-colored areas on the Surface such as ice, causes some of the Solar radiation to be reflected back out to Space without contributing any energy to the Earth System. The adjustment factor for this correction is 0.7.
After applying these adjustments, the net Solar energy absorbed by the Earth System is 240 Watts/m^2.
The graph on the right shows the black body model for an Earth System at a mean temperature of 255 K, a temperature that results in the same 240 Watts/m^2 being emitted out to Space.
Of course, the Earth System is not a perfect black body, as shown by the graph in the upper panel of the illustration below, which plots actual observations from 20 km looking down. (Adapted from Grant Petty, A First Course in Atmospheric Radiation, Figure 8.2, http://www.sundogpublishing.com/AtmosRad/Excerpts/index.html.)
The actual measured radiation is the dark squiggly curve. Note that it jigs and jags up and down between the topmost dashed curve, which is the black body spectrum for a temperature of 270 K and a lower dashed curve which is the black body spectrum for 230 K. This data was taken over the Arctic, most likely during the daytime. The Petty book also has a graph looking down from over the Tropical Pacific which ranges from 300 K down to 210 K. Observations will vary by tens of degrees from day to night, summer to winter, and Tropical to Polar.
However, it is clear that my result, based on matching 240 Watts/m^2, is within a reasonable range of the true mean temperature of the Earth System as viewed from Space.
NOTE ABOUT THE ABOVE ILLUSTRATION
WUWT readers will notice some apparent inconsistencies in the graphs above. The top and bottom panels, from Petty, peak at 15μm to 20μm, while the purple, blue, and black curves in the middle panel, and the Earth System curves from the Carleton spreadsheet I used (see above) peak in the 9μm to 11μm range. Also, the Petty black body curves peak at a “Radiance” around 100 mW/m^2/sr cm^-1 while the black body curves from Carleton peak at an “Intensity” of around 14 W/m^2/μm. Furthermore, if you look closely at the Petty curves, the labels on the black body curves are mirror image! What is going on?
Well, I know some of the reasons, but not all. (I hope commenters who are more fluent in this than I am will confirm my explanations and provide more information about the differences between “Radiance” and “Intensity”.) I have Googled and Wikied the Internet and am still somewhat confused. Here is what I know:
- The horizontal axis in Petty’s plots are what he calls “Wavenumber”, increasing from left to right, which is the number of waves that fit into a cm (centimeter, one hundredth of a meter).
- This is proportional to the frequency of the radiation, and the frequency is the inverse of the wavelength. Thus, his plots are the mirror image of plots based on wavelength increasing from left to right.
- The spreadsheet I used, and my previous experience with visual, and near-, mid-, and far-IR as used in military systems, always uses wavelength increasing from left to right.
- So, when I constructed the above illustration, I reversed Petty’s curves, which explains why the labels on the black body curves are mirror image.
- Fortunately, Petty also included a wavelength legend, which I faithfully reproduced, in non-mirror image, at the top of each plot.
But, that still does not explain why the Petty black body curves peak at a longer wavelength than the Carleton spreadsheet and other graphics on the Internet. I tried to reproduce Petty’s blackbody curves by multiplying the Carleton values by the wavelength (μm) and that did not move the peak to the right enough. So, I multiplied by the wavelength again (μm^2) and, voila, the peaks agreed! (I hope some WUWT reader will explain why the Petty graphs have this perverse effect. advTHANKSance!)
ANSWERING THE OBJECTIONS TO BASIC ATMOSPHERIC “GREENHOUSE EFFECT” SCIENCE
First of all, let me be clear where I am coming from. I’m a Lukewarmer-Skeptic who accepts that H2O, CO2 and other so-called “greenhouse gases” in the Atmosphere do cause the mean temperature of the Earth Surface and Atmosphere to be higher than they would be if everything was the same (Solar radiation, Earth System Albedo, …) but the Atmosphere was pure nitrogen. The main scientific question for me, is how much does the increase in human-caused CO2 and human-caused albedo reduction increase the mean temperature above what it would be with natural cycles and processes? My answer is “not much”, because perhaps 0.1ºC to 0.2ºC of the supposed 0.8ºC increase since 1880 is due to human activities. The rest is due to natural cycles and processes over which we humans have no control. The main public policy question for me, is how much should we (society) do about it? Again, my answer is “not much”, because the effect is small and a limited increase in temperatures and CO2 may turn out to have a net benefit.
So, my motivation for this Visualizing series is not to add to the Alarmist “the sky is falling” panic, but rather to help my fellow Skeptics avoid the natural temptation to fall into an “equal and opposite” falsehood, which some of those on my side, who I call “Disbelievers”, do when they fail to acknowledge the basic facts of the role of H2O and CO2 and other gases in helping to keep temperatures in a livable range.
Objection #1: Visual and near-visual radiation is merely “light” which lacks the “quality” or “oomph” to impart warmth to objects upon which it happens to fall.
Answer #1: A NASA webpage targeted at children is sometimes cited because they say the near-IR beam from a TV remote control is not warm to the touch. Of course, that is not because it is near-visual radiation, but rather because it is very low power. All energy is fungible, and can be changed from one form to another. Thus, the 240 Watts/m^2 of visible and near-visible Solar energy that reaches and is absorbed by the Earth System, has the effect of warming the Earth System exactly as much as an equal number of Watts/m^2 of “thermal” mid- and far-IR radiation.
Objection #2: The Atmosphere, which is cooler than the Earth Surface, cannot warm the Earth Surface.
Answer #2: The Second law of Thermodynamics is often cited as the source of this falsehood. The correct interpretation is that the Second Law refers to net warming, which can only pass from the warmer to the cooler object. The back-radiation from the Atmosphere to the Earth Surface has been measured (see lower panel in the above illustration). All matter above absolute zero emits radiation and, once emitted, that radiation does not know if it is travelling from a warmer to a cooler surface or vice-versa. Once it arrives it will either be reflected or absorbed, according to its wavelength and the characteristics of the material it happens to impact.
Objection #3: The Atmospheric “Greenhouse Effect” is fictional. A glass greenhouse works mainly by preventing or reducing convection and the Atmosphere does not work that way at all.
Answer #3: I always try to put “scare quotes” around the word “greenhouse” unless referring to the glass variety because the term is misleading. Yes, a glass greenhouse works by restricting convection, and the fact that glass passes shortwave radiation and not longwave makes only a minor contribution. Thus, I agree it is unfortunate that the established term for the Atmospheric warming effect is a bit of a misnomer. However, we are stuck with it. But, enough of semantics. Notice that the Earth System mean temperature I had to use to provide 240 Watts/m^2 of radiation to Space to balance the input absorbed from by the Earth System from the Sun was 255 K. However, the actual mean temperature at the Surface is closer to 288 K. How to explain the extra 33 K (33ºC or 58ºF)? The only rational explanation is the back-radiation from the Atmosphere to the Surface.
Dave Springer, now you are speaking real sense in the last few comments. I’m just nodding as I read. If you have time read back on some of my comments and those revised 24hr T&K spreadsheets near the top and you should find they fit to what you have been saying just fine. Miskolczi’s figures as a 24hr spread are quite a bit off of T&K’s but the general view is the same, his shows more atmosphere absorption of SW, less of window LW. (if you find mistakes, let me know, I am human too)
@ur momisugly Joel Shore
At any rate no matter who is right or wrong regarding AGW the cautionary principle compels looking at what practical ramifications come with AGW.
As far as I can determine the net practical effect of AGW is all reward and little risk. Obervation and theory both support an AGW effect over landmasses at times when temperatures are the coldest and the air is the dryest. In other words we should expect AGW to be milder winters in the high latitudes. If you bother to ask people who live in high nortern latitudes whether they’d welcome milder winters the answer is overwhelmingly yes. Few people enjoy harsh winters and the plants and animals that struggle to survive in sub-freezing temperatures, if they could talk, would certainly vote for milder winters as well. Adding substantially to the benefits of milder northern winters (extended growing seasons, cattle farms and apple orchards in Greenland, and things of that nature) is the effect of increased CO2 on primary production in the food chain (green plants). Higher levels of CO2 almost universally accelerate plant growth rate and at the same time reduce water use per unit of growth. These are fantastically good things and indeed we are already enjoying the fruits (pun intended) of going from 280ppm to 380ppm CO2 and the benefits will continue to accrue at least up through 2000ppm. In the best possible scenario it would end the ice age and allow the earth to return to it’s historically predominant state of being green from pole to pole. That’s a good thing unless for some strange reason you prefer barren rocks and ice to forests and grasslands. I sure prefer a living world to a dead one!
So what’s not to like about AGW? Rising sea level is about it. The thing of it is that sea level will rise very slowly giving us and the rest of the living world many centuries in which to slowy adapt. There is no evidence at all that sea level will increase faster than the current ~3mm/year or about a foot per century. In fact there’s no evidence at all the largest store by far of ice (Antarctica) is reducing at all. If anything it’s getting colder there and continental AGW is confined to the northern hemisphere.
Contrast these great net benefits of continually rising CO2 with what it would cost to stabilize it at current level. The industry that makes if possible for a rising human population to enjoy rising standard of living is driven in large measure by fossil fuel consumption. Anything that makes fossil energy more expensive and/or less available will result in a fall of living standards and the poor will take the brunt of it because they lack the excess disposable income to absorb higher energy costs.
The only possible conclusion for me is that anyone armed with the objective facts surrounding AGW who supports draconian measures to reduce fossil carbon emissions has an agenda driven by misanthropy. The rest who support are simply don’t have the facts at hand to reach a reasoned decision. I’m not trying to influence how people decide but am rather just trying to get the facts on the table trusting that most people will make the right decision once they know the real story instead of the hysterical misrepresentations peddled by miscreants like Al Gore, James Hansen, Michael Mann, what’s his face Pachauri (head of the UN IPCC), and the rest of the usual suspects.
@ur momisugly Ira
Thanks for the offer of publishing an article I might want to write regarding an oceanic greenhouse but I’m already approved for author level on WUWT and can do it myself. It’s not unfamiliarity with WordPress publishing either as I was the top level adminstrator on a high traffic wordpress blog for several years. During that time I composed and published hundreds of articles.
The bottom line is I get more satisfaction being on an equal footing with regular subscribers. Authors get advantages that make for an unlevel playing field and I’d prefer mine to be level.
That said you are of course welcome to investigate and publish something yourself if you think it’s warranted and I will, as usual, be a prolific commenter in the thread as greenhouse physics fascinates me.
jae says:
May 15, 2011 at 7:10 pm
“It seems clear to me that the “jury is still out” regarding even the most basic, simple part of the CAGW junkscience: the GHE theory.”
Take your blinders off. The “jury” has been “in” regarding the longwave absorptive and emissive properties of greenhouse gases for over 150 years since physicist John Tyndal proved it experimentally. CO2 level sensors commonly employed in commercial building ventilation systems use exactly the same physics that Tyndal provied in his experiments. Infrared thermometers which today are inexpensive thermometers allow the amateur experimenter with the most limited budget to confirm that the sky glows in the infrared. More expensive infrared spectrometers outside the amateur budget looking upward from the ground and downward from satellites also confirm what Tyndal found only with far better ease, accuracy, and precision.
You’re in denial – either mentally or emotionally unable to accept physics facts derived by both theory, experiment, and widespread employment in practical applications.
A common expression from my time in the USMC comes to mind: What the f**k is your major malfunction?
R Stevenson says:
May 16, 2011 at 9:06 am
Mr. Stevenson glad to see someone else talking emisivity of CO2. However, if memory serves me when H2O and CO2 are both available my heat transfer book had
(Pw/(Pw+Pc)-1) as the combination emissivity. Pw is partial pressue of water vapor and Pc partial pressure of CO2. And at low temperatures less than 500 R the emissivity of CO2 is very low. Granted this is from memory and the Hottel charts are a touch vague in my mind.
mkelly says:
As I pointed out, it doesn’t matter what you say: If you take your logic to its obvious conclusion, it shows the greenhouse effect because the earth receiving energy from the sun must emit heat. You have just admitted that this won’t happen as long as the atmosphere is the same temperature as the surface. So, the surface will increase its temperature…In fact, it has to increase its temperature until the difference in temperature between the atmosphere and the surface is enough to support heat flow away from the earth’s surface that is equal to what it receives from the sun.
RStevenson says:
You are correct that you will eventually have to solve for what the final temperature of the atmosphere will be. However, the point is simply this: As long as you have an IR-absorbing atmosphere that is at a nonzero temperature, the earth’s surface will have to be at a warmer temperature (in order to radiate away the energy that it receives from the sun) than it would be if the atmosphere did not absorb any of the IR radiation that the earth emits.
There is no reason why we ever have to talk about “back-radiation”. As long as you emit that the heat flow between two bodies at different temperatures depends on the temperature of the colder body as well as the hotter body, then the game is over (and you’ve lost). It’s as simple as that.
Ira Glickstein, PhD says:
May 15, 2011 at 11:28 am
I agree that some of the downwellng radiation comes from very low reaches of the Atmosphere, but why does that make a difference in this discussion? Does it matter to the argument that hundreds of Watts/m^2 pass from the Atmosphere to the Surface due to the ill-named “greenhouse effect”?
—
Ira, you still don’t see what I am saying. You agree that SOME of the downward pointing radiation comes from the low reaches of the atmosphere but I am saying ALL of the downward radiation measurable at the surface is from the low reaches (just 10’s of meters) EXCEPT (minus) that which can and does go upward to space and that is called the “window” frequencies upward IR radiation.
Re-read my statements above, I am not saying some, I am saying all. This is so because the atmosphere is totally opaque to these frequencies outside any particular frequency that you could call a “window” frequency. The window frequencies are a class of frequencies, not necessary a contiguous band, some lines may be anywhere and all are not total but partial by their exact measured radiance. It is the sum of all of these partial window frequencies together that make up the upward “window IR radiation”. That is what Dr. Miskolczi went to great lengths to accurately measure, not only once, but at different seasons and different latitudes at many points on the globe. Now do you see?
Dave Springer says:
…And, contradicted by the satellite data that show the opposite. And, it is understood that the trends in the radiosonde data are artifacts due to instrumentation that was never designed to look at trends of this sort.
I have noted to you ( http://wattsupwiththat.com/2011/05/07/visualizing-the-greenhouse-effect-light-and-heat/#comment-660881 ) that, as near as I can tell, your whole notion here is based on a simple misreading of what they said…They talked about “net LWIR” and you somehow misinterpreted as just the emitted part.
So, you seem to be predicting either a much bigger “hot spot” than what the models predict or some sort of cloud-albedo feedback that you have provided no real evidence for.
Climate models make neither of those assumptions. To the extent that either of these end up being constant in the models, they are predictions that come out of the physics in the models, not assumptions.
Your conclusions about the impacts essentially fly in the face of the actual science on impacts (or, at best, look at only a small part of the impacts). It is too far afield to get into impacts in this thread, but to believe that you understand the impacts better than the scientists studying them is not realistic in my view.
Dave Springer says:
The only way it could be much larger is if precipitation was way-underestimated because you can get the amount of energy carried away from the surface as latent heat just by knowing the amount of water evaporated, which is equal to the amount precipitated, as long as you average over a reasonable period of time. Maybe you can try to make some argument at the margin (i.e., for a change) but you certainly can’t say that latent heat transport is current much larger.
richard verney says:
May 12, 2011 at 8:39 pm
It depends on your assumptions regarding clouds and albedo. Clouds or no clouds? Surface albedo or blackbody? Here’s the calcs, assuming a solar “constant” of say 342 W/m2 global 24/7 average.
Actual average temperature: ~ 14°C
No atmosphere blackbody temp: 6°C
Less – cloud albedo: -10°C
Less – surface albedo: – 18°C
The final figure is the one usually quoted, and gives the ~ 33K warming you cite above. The net effect of adding our existing atmosphere to a blackbody no-atmosphere earth is much smaller, about 8°C.
Dave Springer says:
May 13, 2011 at 6:05 am
I begin my mental investigation of this claim by saying “warming compared to what”? My first comparison would be to compare a given volume (say ten thousand cubic metres, 100m x 100m x 100m) of ocean with the same volume of land. We’ll assume that they have the same albedo.
In both cases, they have the same surface area for radiation of the energy. And both absorb and radiate infrared (IR) in the same manner.
But the ocean can absorb energy much more efficiently because the light penetrates the upper layer.
On the other hand, the ocean can also lose energy much more efficiently because every night it overturns, bringing warmth to the surface. In addition, it loses more energy from evaporation than does the land.
So the question becomes, in a constant day-night alteration of temperature, what would be the final temperature of the two (ocean and land). If an “oceanic greenhouse effect” exists, the ocean should be warmer.
NEGLECTING EVAPORATION and ASSUMING EQUAL CONDUCTION/CONVECTION LOSSES, I’d say the final temperature of the two, ocean and land, would be the same. I reason thusly. They are both absorbing the same amount of energy. They both have the same identical ways to lose energy (radiation and conduction/convection). Therefore, they’d have to end up at the same temperature.
And that means that including evaporation, I’d say the ocean would end up cooler than the land.
So I’d say no oceanic greenhouse effect … but I must confess I haven’t thought too deeply about the question.
w.
mkelly says
‘(Pw/(Pw+Pc)-1) as the combination emissivity. Pw is partial pressue of water vapor and Pc partial pressure of CO2. And at low temperatures less than 500 R the emissivity of CO2 is very low. Granted this is from memory and the Hottel charts are a touch vague in my mind.’
Emissivity of CO2 depends on PcL as well as tempertature. At 500 R it can be as high as 0.2 for a PcL of 5.0 ft.atm. When CO2 and water vapour are present together a correction is made to reduce the sum of their emissities using a plot of correction factor v Pw/(Pc+Pw) for particular temperature/PcL +PwL values. In the case of atmospheric calculations with water vapour so dominant I’m not sure how much effect a correction would have.
Ira, I said ALL and I have told myself over and over to be real careful when saying “all”, “total”, “100%” when talking physics. Please change my word “all” above to “so close to all that the small difference remaining doesn’t matter at the current precision we are speaking of (2-3 digits)”. See how many words it takes to say it properly? I tend to assume someone else is going to know “all” in that particular case of radiation is not absolutely 100%, totally every single photon with no exceptions, for in radiation that so rarely happens when speaking of gases. Sorry.
I’d have to agree with Willis though there are those absolute words again “same”, I’d just say “very close to the same” and I’m automatically assume Willis meant the same.
Willis, thanks for just reminding everyone here that you cannot have lopsided thoughts touching physics, there is an other side of the equation you have to worry about an account for except in the rarest of cases. If there is a plus effect, look for the minus effect on the other side and account for that too.
I even think this same thought applies to CO2. With increased CO2 there will be more absorption of energy within the atmosphere in the CO2 bands in SW frequencies. Anyone following what I have been saying, that any energy that is “in the atmosphere” is destined to be ejected to space, that net energy cannot find itself EVER warming the surface because lower in the atmosphere is always warmer and ‘that’ net energy (heat) cannot travel downward from cooler to warmer. So, that additional SW absorbed due to the CO2 will cancel some, if not all, or even more, of the absorption upward in LW IR. You never hear about that being accounted for either.
We could use a new thread… i..t..’..s g..e..t..t..i..n..g s..l..o..w..!..!
Joel Shore says:
May 16, 2011 at 11:42 am
mkelly says:
Sorry Joel, let change q to the more oft used q/A or W/m^2. If one side of the equation is zero then the other is too. So no energy exchange. Watt is joule per second and a joule is a unit of energy I will let my statement stand.
“As I pointed out, it doesn’t matter what you say: If you take your logic to its obvious conclusion, it shows the greenhouse effect because the earth receiving energy from the sun must emit heat. You have just admitted that this won’t happen as long as the atmosphere is the same temperature as the surface. So, the surface will increase its temperature…In fact, it has to increase its temperature until the difference in temperature between the atmosphere and the surface is enough to support heat flow away from the earth’s surface that is equal to what it receives from the surface.”
I agree. Never said anything different. But it is temperature gradient that matters period. Not back radiation as you and Ira say. I have said several times the two requirements for heat transfer are path and temperature gradient.
All gases absorb heat from the surface so we must account for them and 99% give no/little IR radiation.
I also said now lets get to the temperature of the atmosphere you want to use and the emissivity etc to further the discussion.
Thanks for admitting I was correct since you used “temperature” 4 times and not once back radiation.
Dave Springer says:
Besides the fact that we don’t seem to be seeing a much greater-than-predicted temperature rise in the upper troposphere that this sort of picture would seem to need, I think there is a fundamental error that you (and Martin Lewitt in some previous comments) are making here: This error is basically summarized by considering a simple calculation done by L.D. Danny Harvey’s in “Global Warming: The Hard Science”. What he shows is that a change in the radiative balance between the surface and the atmosphere even by a larger amount, such as 10 W/m^2 would result in only a very small surface temperature change while a change in the greenhouse effect (i.e., the radiative balance between the earth and space) by 10 W/m^2 results in a much larger surface temperature change (almost 2 orders of magnitude larger if I recall correctly). The same would presumably be true if instead of a change in radiative balance, you had a change in some other heat transfer process like the water cycle.
The reason is simply this: Because of convection, the lapse rate in the troposphere is primarily determined by the stability limit that it can’t be larger than the (appropriate) adiabatic lapse rate. So, if you “try” to change the temperature structure of the atmosphere by changing the heat flows between the surface and atmosphere, the atmosphere just responds by altering the convection to cancel out most of this change and you end up with basically the same temperature structure you started with (modulo the issues involving the moist adiabatic lapse rate…i.e., the fact that the adiabatic lapse rate changes some with heating, which genuinely does cause a change in the temperature structure and leads to the lapse rate feedback, a negative feedback already included in all of the climate models).
However, if you actually alter the energy balance between the earth and space, as increasing the greenhouse effect does, then the fact that the temperature structure must remain the same leads to a significant increase in surface temperatures.
So, in summary:
Altering the heat transfer between the earth system and space => Significant effect on surface temperatures.
Altering the heat transfer between the earth’ surface and atmosphere => Only a small effect on surface temperatures.
I think this is alluded to, albeit rather cryptically, in the Wentz et al. paper that Martin Lewitt cited above ( http://www.sciencemag.org/content/317/5835/233.full ), and helps to explain why people like Martin have put an interpretation on the paper that you don’t find in the Wentz paper itself or in other papers that talk about how the hydrological cycle changes under global warming. In particular, what Wentz et al. say say is:
mkelly says:
So, what are we arguing about then? You admit there is a greenhouse effect?
There can be different ways of looking at the same thing. It is not necessarily a matter of one being correct and the other incorrect. The heat flow (i.e., net energy transfer) that occurs is determined by the two objects being at different temperatures.
For radiation, the way that this comes about is that both objects emit radiation, but the hotter one emits more than the colder one. However, if this picture confuses you, then you can just stick to the heat flow equation and don’t have to worry about how it is coming about on a more microscopic level.
Joel Shore says:
May 16, 2011 at 1:39 pm
Besides the fact that we don’t seem to be seeing a much greater-than-predicted temperature rise in the upper troposphere that this sort of picture would seem to need, I think there is a fundamental error that you (and Martin Lewitt in some previous comments) are making here: …
———–
And here comes all of your bulk AGW science and wrong assumptions IMHO bought in by crappy AGW books. I don’t buy any of it Joel Shore, not without the science, I read your words. You would have to prove it to me one tiny factor at a time and if you are able to make each one bulletproof I would then apologize, if it is true I will usually recognize it as true, or tell you why not, or possibly put on the “just don’t know” stack… not enough data to say either way.
This type of bulk comment is why people are getting skeptical by the droves, the more of this they hear “authority… this author says this, that author says that” the more their gut says no, it makes no sense (observation). I don’t want to hear of some author, don’t care about his name, or his claimed qualifications, I want to hear the science and physics behind his conjectures, each one a tiny step at a time.
You just brought in the concept of trapped heat again, BS and I will show you why if you will let me, there is a very tiny component there but it is small. You just brought in the concept of warped atmospheric profiles by CO2 again, BS and I will show you why if you will let me, it can’t be warped by a GHG that would affect us, it can’t be re-based.
I just felt this was coming. The science Joel, not some book, not some claims somebody made, dig out the science points they are building their claims on and present the science point by point, most here know science well enough to handle it. You know the ones that can’t so let them be.
Dave Springer says on May 15, 2011 at 7:40 am :
“Can someone help me out here? ——- The ocean therefore must be a greenhouse fluid. ———– Can someone help me out here? I’m crowd sourcing for an answer.”
Yes Dave, I can be said to be one in a crowd and I can say I have always thought the “oceans” – that’s plenty of water – may be likened to the little heater that keeps the greenhouse warm at night.
But don’t take to much notice of me as I also believe that Advection i.e. the kind of horizontal air movements that follow isobaric surfaces and therefore are predominantly horizontal) have got more of a Green House Effect (GHE) than does a radiation circuit, of say 324 W/m² originally removed from the surface, and then returned via Green House Gases (GHGs) – which, by the way, show no sign of having warmed at all (no hot spot) But even so, when somehow the same 324 W/m² are delivered back to the surface for absorption it is supposed to be getting warmer.
(Tip – Two bank accounts for frequent money transfers may be enriching)
I hope I have been of some small help to you in your greenhouse fluid research.
PS. Just realised I may be very wrong as in the AGW world there is never night, not as we know it. – Average Solar Irradiation (SI) = 240 W/m², but an average no SI = 0 W/m² or night which would make SI irrelevant when heating by gas happens doesn’t get a look in.
Total agreement! I recommend that all on this thread re-read Dave Springer’s posting May 16, 2011 at 10:35 am.
As http://wattsupwiththat.com/2011/01/06/co2-is-plant-food-clean-coal-say-watt/ Lord Monckton told Congress, “CO2 is plant food.” Hearing this, the Global Warming activists went crazy because … well, because they know he spoke an inconvenient truth.
As for temperature increase, when I moved from New York to Florida to gain around 15ºC. How many doublings of CO2 would be equivalent to that temperature increase? Not that I think the world, on average, needs as much as 15ºC, but it it totally ridiculous that the Alarmists (and Warmists) are aghast at the supposed 0.8ºC rise since 1880 they think they’ve measured (of which about 0.3ºC is probably data bias and only about 0.2ºC is due to human activity). Or even that they think they can measure mean temperatures down to fractions of a degree for the entire globe.
PS: I also saw your subsequent comment, Dave, where you say you prefer not to post a new topic on the ocean “greenhouse effect” even though you have WUWT Author status. I hope you change you mind or that someone else does so because it is a facinating concept that, if it pans out, will revolutionize climate science and totally consign the CAGW crowd and the Team to ignominy.
Ira Glickstein says:
The part we are aghast about is not the amount of warming that we have had so far but the amount that we are committing ourselves to in the future.
And, another way to look at temperature changes is this: During the last ice age, when there was like a mile of ice on top of where I currently am, the global temperature was only about 5-7 C colder than it is today. Yes, temperatures of just a few C matter.
wayne says:
I explained the basic physics behind it. If you want to see all the gory details, then buy the book and read it. Do you expect to be spoon-fed everything that you want, especially after repeatingly demonstrating that it does no good anyway? Really…we should just be leaving you guys to believe any nonsense that you want to believe!
@joel
Well you may be modestly well informed in the physics department but you suck in biology. The biological effects of CO2 are very well characterized. More CO2 is virtually all upside and no downside. You buy into the hysterics promulgated by Al Gore & company to believe otherwise. That must describe you.
OK, Wayne, let me agree with you that ALL the individual downwelling photons from H2O, CO2, and all other so-called “greenhouse gases” to the Surface comes from “just 10’s of meters”. As a first approximation I am willing to believe that is actually true for some altitude that is a relatively tiny percentage of the total height of the Atmosphere. So let us draw “Wayne’s line”at that level.
Does that mean that if all the rest of the Atmosphere above Wayne’s line was pure N2 then the Surface temperatures would be unaffected? In other words, are you claiming that the “greenhouse gases” above Wayne’s line have no role in the quantity of downwelling radiation reaching the Surface?
I do not think that is so. The reason is that the “greenhouse gases” below Wayne’s line, as we know, emit roughly half their photons up and the other half down. Those that happen to go upwards would continue out to Space absent the “greenhouse gases” that are above Wayne’s line.
Given that there are “greenhouse gases” above Wayne’s line, most of the upward-going photons from below Wayne’s line will be absorbed in “just 10’s of meters”. About half of those absorbed photons will be re-emitted downwards back below Wayne’s line and will be absorbed by “greenhouse gases” there. Thus, some of the photons coming down to the Surface will be the end result of a series of transactions that took place both below and above Wayne’s line.
Yes, the specific photon that strikes the Surface came from a molecule below Wayne’s line. But, the energy in that photon may be from a second or third or fourth … etc. transaction, some of which may have taken place above Wayne’s line.
Indeed, assuming the area below Wayne’s line is where ALL the photons from the Atmosphere to the Surface originated, I can tell you that about half those photons are from single transactions totally below Wayne’s line, about a quarter involve transactions above Wayne’s line but below a Wayne’s line #2 that is “just 10’s of meters” above the first Wayne’s line, about an eighth from the area between Wayne’s line #2 and #3, and so on and on, much of the way up the height of the Atmosphere.
@Ira
The Hockey Team is doing a fine job consigning themselves to ignomy. The signature of inevitable defeat was when the memo went out saying “global warming” is out and “climate change” is in. They realized at that point the jig was up about global warming. It wasn’t happening at an alarming rate and the pitiful scientific narrative fell apart.
The next shoe fell when “climate change” morphed into “climate disruption” because every fool knows the climate changes and most of them who didn’t sleep through elementary school science classes learned there were glaciers covering the earth 10,000 years ago and these glaciers are overdue for a comeback.
Climate disruption might actually be an accurate term and they should stick with it and hope the next few decades provide some kind of empirical validity to it so at least they won’t go down in the history books as the largest collection of scientific jackasses since Ptolemy’s merry band of epicyclic cipherers were still breathing.
No problem, Wayne, as an engineer I always interpret “all” to mean more than “two-sigma” (95%) or “three-sigma” (99.5%), depending upon the context, up to the point where, as you say, “the small difference remaining doesn’t matter “. I agree that the accuracy of virtually all estimates in the area of climate science does not justify any high level of precision. As you may have noticed, I tend to round my results so as not to imply high precision.