Guest post by Reed Coray
The following example illustrates the issues I have with reasoning often used to argue that increasing the amount of CO2 in the Earth’s atmosphere will increase both the Earth’s surface temperature and the Earth’s atmosphere temperature. Immediately following is a direct quote from URL
http://www.school-for-champions.com/science/heat_transfer_earth.htm
“The present situation is that there has been an increase in infrared-absorbing gases in the atmosphere, such as carbon dioxide (CO2) and methane (CH4). Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere and spreading through convection currents. The average temperature of the atmosphere has increased 0.25 °C since 1980, mainly attributed to an increase in infrared-absorbing gases in the atmosphere.”
Although the above statement makes no direct reference to Earth surface temperature, I believe it carries the implication that greenhouse gases in the Earth’s atmosphere increase the Earth’s surface temperature.
I make two comments: the first is relevant only if the above implication is valid, the second is relevant independent of the validity of the implication. First, placing matter adjacent to a warm surface such that the matter is capable of absorbing/blocking radiation to space from the warm surface can lead to a decrease in the warm surface’s temperature. Second, increasing the amount of the absorbing/blocking matter can lower the temperature of the absorbing/blocking material.
Take for example an internal combustion engine whose metal surface is exposed to a vacuum. In addition to doing useful work, the engine produces thermal energy (heat). That thermal energy will produce a rise in the temperature of the engine’s surface such that in energy-rate equilibrium the rate energy is radiated to space from the engine’s surface is equal to the rate thermal energy is generated within the engine. By attaching radiating plates to the engine’s surface, some of the energy radiated to space from the engine’s original surface will be absorbed/blocked by the plates; but because thermal energy can be transferred from the engine to the plates via both radiation and conduction, the temperature of the engine’s original surface will be lowered. This is the principle of an air-cooled engine[1]: provide a means other than radiation of transferring heat from an engine to a large surface area from which heat can be removed via a combination of conduction, convection and radiation, and the engine’s surface temperature will be lowered.
If plates at a temperature lower than the original engine surface temperature are attached to the engine, it’s true that the temperature of the plates will increase to establish energy-rate equilibrium. Once energy-rate equilibrium is established, however, increasing the plate radiating area (adding additional matter that blocks more of the energy radiated from the original engine surface) will likely lower the plate temperature.
Thus, blocking the amount of surface radiation escaping to space does not necessarily increase the surface temperature; and increasing the amount of radiation blocking material does not necessarily increase the temperature of that material. In both cases (the Earth/Earth-atmosphere and the internal combustion engine in a vacuum), the heat eventually escapes to space–otherwise the temperature of the Earth’s surface and the engine would continue to rise indefinitely. The difference isn’t that the energy doesn’t eventually escape to space (it does in both cases), the difference is in the path the energy takes to reach space. The amount of generated thermal energy in conjunction with the path the thermal energy takes to get to space determines temperatures along the path; and adding more material may increase or decrease those temperatures. To say that “Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere…” by itself is unwarranted; because an equivalent statement for the case of adding extra plate material to the engine would be “Energy that would normally escape to space from an engine with small attached plates is absorbed by additional plate material, thus heating the plates…” For air-cooled engines, this statement is not true—otherwise the plate surface area of air-cooled engines would be as small as possible.
It’s fairly easy to visualize why (a) adding thermally radiating plates to an air-cooled engine might decrease the engine’s surface temperature, and (b) increasing the area of the radiating plates might decrease the plate temperature. It’s not so easy to visualize, and may not be true, why (a) adding greenhouse gases to the Earth’s atmosphere decreases the Earth’s surface temperature; and (b) increasing the amount of atmospheric greenhouse gases lowers the temperature of the Earth’s atmosphere. I now present one possible argument. I do not claim that the argument is valid for greenhouse gases in the Earth’s atmosphere, but I do claim that the argument might be valid, and can only be refuted by an analysis more detailed than simply claiming “Energy that would normally escape into space is absorbed by these molecules, thus heating the atmosphere.”
If we assume that (a) matter cannot leave the Earth/Earth-atmosphere system, and (b) non-greenhouse gases radiate negligible energy to space, then for a non-greenhouse gas atmosphere the only way thermal energy can leave the Earth/Earth-atmosphere system to space is via radiation from the surface of the Earth. The rate radiation leaves the surface is in part a function of both the area and temperature of the surface. For a greenhouse gas atmosphere, energy can leave the Earth/Earth-atmosphere system to space both via radiation from the Earth’s surface and radiation from greenhouse gases in the atmosphere. Suppose it is true that the density of greenhouse gases near the Earth’s surface is such that radiation emitted from low-altitude greenhouse gases does not directly escape to space, but is in part directed towards the Earth’s surface and in part absorbed by other atmospheric greenhouse gases. As the atmospheric greenhouse gas density decreases with increasing altitude, radiation emitted from high-altitude greenhouse gases can directly escape to space.
Now it’s not impossible that since (a) in addition to radiation, heat is transferred from the Earth’s surface to greenhouse gases via conduction, and (b) convection currents (i) circulate the heated greenhouse gases to higher altitudes where energy transfer to space can take place and (ii) return cooler greenhouse gases to the Earth’s surface, that the process of heat transfer away from the Earth’s surface via greenhouse gases is more efficient than simple radiation from the Earth’s surface. Many engines are cooled using this concept. Specifically, a coolant is brought into contact with a heated surface which raises the coolant’s temperature via conduction and radiation, and the coolant is moved to a location where thermal energy transfer away from the coolant to a heat sink is more efficient than direct thermal energy transfer from the heated surface to the heat sink.
One way to realize increased thermal transfer efficiency would be to use a coolant, such as greenhouse gases, that efficiently radiates energy in the IR band (i.e., radiates energy at temperatures around 500 K). Another way would be to spread the heated coolant over a large surface area. Since surface area increases with increasing altitude, thereby providing expanded “area” (in the case of a gas, expanded volume) from which radiation to space can occur, it’s not clear to me (one way or the other) that greenhouse gases won’t act as a “coolant” reducing both the temperatures of the Earth’s atmosphere and the Earth surface.
[1] It’s true that for most air-cooled engines the main transfer of heat from the engine plates is via a combination of (a) conduction of heat to the air near the plates, and (b) convection that replaces the warm air near the plates with cooler air. To aid this process, a fan is often employed, or the engine is located on a moving vehicle and the vehicle’s motion through an atmosphere provides the flow of air across the plates. Although conduction/convection may be the primary means of heat dissipation from the plates, radiative cooling also dissipates heat.
joeldshore;
And, amongst the larger physics community, there is not only acceptance of the greenhouse effect but generally acceptance of the danger of AGW, as evidence by such things as the American Physical Society statement on climate change>>>>
1. Argument from authority
2. The statement by the APS is largely political in nature.
Proposing an alternative analogy.
Water makes a good analogy for all sorts of things, for example electricity. Voltage is analogous to water pressure, amperage to flow, resistance to resistance.
Imagine a lake as Earth’s energy:
Water In to the lake = Energy In to the Earth;
Water Out of the lake= Energy Out from the Earth;
Lake Level = Amount of Energy in the System which correlates to temperature of the system.
The lake’s dam is the atmosphere; it has a hole in it to allow water out analogous to IR.
The question is does adding CO2 to the atmosphere increase the energy out = increase the hole’s size thereby reducing lake level (temperature) or does it decrease the energy out = decrease the hole’s size thereby increasing lake level (temperature).
Honestly, I can see it both ways; but I look at the outgoing radiation profile with its dips that correspond to GHG frequencies and can’t help but conclude the increase in GHG decreases the outgoing radiation (makes the hole in the dam smaller). I could be wrong; the outgoing radiation may be being distributed from GHG frequencies to other frequencies in such a way as to make the others and the total higher than they would be in the absence of GHG’s.
From the beating a dead horse department: The satellite measuring increases in outgoing IR vs. the model outputs:
http://wattsupwiththat.files.wordpress.com/2012/02/image26.png
That shows at least when temperature rises, the energy out increases, which is analogous to the lake level rising increasing the pressure at the hole in the dam thereby increasing flow out which makes sense given what we know about physics (somewhat confirming the analogy); whereas the models predict analogously that as the lake level rises the water flow out decreases, obviously wrong for the analogy and I suspect for outgoing radiation as well.
However, it is radiating at a lower temperature, is it not?
Of couse, I guess there is also the work done raising that air to the tropopause. I wonder how much extra energy all this churn gets rid of.
Bart says
The retained energy, and necessarily the surface temperature, goes down.
Henry says
also wrong: it is such a pity that climate scientists have decided to ‘log” average temps. and not maxima;
there is so much to learn from maxima,
as it tells us about the energy input that we get from the sun
It follows on a natural curve – on an (apparent) 50 year warming followed by a 50 year cooling.
I strongly suspect it has to do with the sun-UV-O2-O3 cycle.
Does 7 x 7 + 1 ring a bell somewhere?
http://www.letterdash.com/henryp/global-cooling-is-here
“the heat eventually escapes to space–otherwise the temperature of the Earth’s surface and the engine would continue to rise indefinitely.”
TY, this is a point i have made in laymans terms for a long time…..IF co2 or anything else was trapping heat, meaning NOT allowing the heat to escape into space then each day the earth would be hotter than the day before and we would have been a cinder long ago…..clearly and obviously the heat energy input from the sun 24/7 does escape back into space and the greenhouse effect simply SLOWS the movement but in no way stops it or reverses it(reversal is REQUIRED for a greenhouse gas to warm the surface it MUST reverse the natural flow of the radiation from the earth towards space).
rgbatduke says on July 21, 2012 at 11:31 am:
“Yes, it gets very tedious explaining to them over and over again how the GHE works. But it isn’t made easier by claiming that it “warms” anything. It — as you do say — simply elevates the mean temperature until equilibrium is re-established between an internal source of heat delivered directly to the Earth’s surface by unblocked, non-reflected sunlight and heat loss via radiation out of an imaginary surface that contains the Earth and its atmosphere.”
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Have you ever considered the possibility that the idea that LWIR radiation imprisoned in GHGs will work like a blanket, may very well be totally wrong?
Yes there is a “large raft of scientist” out there who know ever so much about radiation, but can you get one of them to explain to me, and other “disbelievers”, how it is that radio-waves can penetrate a brick wall while IR and other “light-radiation” stays on the outside? – I don’t think so. – Consensus, consensus, con——.
I firmly believe that one unit of Energy Radiation (ER) from the Sun warms the surface, once and once only. The Surface’s Solar Energy Absorption Rate (SEAR) is highly variable depending on many things, color and texture being just two of them. – It is however the SEAR that gives rise to the many variations of weather and/or climate.
It only matter to perpetual motion engines, which can keep on using the same energy over and over again, how long radiation stays in the system. – Once the fuel-tank is empty, the engine stops.
The speed of convection from the surface to the top of the Troposphere is what matters to the Greenhouse Effect.
On the “Dark side of the Earth” convection only happens at and around the Urban Heat Islands (UHIs). In other words it is, in nature,non existent. On an overcast day or on the Sunny side of the Earth, convection is reduced in close relation to the amount of cloud-cover.
Regardless of the composition of its atmosphere, any arbitrary planet in equilibrium will emit the same amount of energy that it absorbs. If the portions of a planet’s atmosphere responsible for radiating IR out into space are at the same temperature as the planet, then the atmosphere will have no net effect on the quantity of IR radiated out into space, and the planet will be the same temperature as it would have been with no atmosphere whatsoever (or if it had an atmosphere with no IR-active gases). If these same radiating slices of the atmosphere are warmer than the surface, the planet will end up radiating out more IR than it otherwise would have, and in order for conservation of energy to be followed the surface of the planet will be colder than it would otherwise have been. And, finally, if the radiating segments of the atmosphere are colder than the surface, the planet will radiate less IR out to space than would otherwise have been the case, and the planet’s surface will be warmer than it would otherwise have been, allowing it to radiate out more energy to make up the deficit caused by the colder atmosphere.
The radiating portions of Earth’s atmosphere are colder than the surface.
Ergo, Earth’s surface is warmer than it would be without greenhouse gases.
…Mr. Watts, a question; do you look over these guest posts before throwing them up here? Because, honestly, it does not do much to improve your credibility when you gladly host things like this, which betray a massive lack of comprehension of very, very basic physics. It’s your site, of course, and yours to run as you see fit, but…If I were you, I might be a bit more picky about things like this post. Quite frankly, this is embarrassing.
I want to thank everyone who commented, both favorably and unfavorably, to this guest post.
To Dr. Brown (July 21, 2012 at 6:41 am). If in anyway I implied that my thoughts were original, I apologize. I’m pretty sure intelligent and knowledgeable people have looked at the issues expressed in my paper and have concluded that greenhouse gases cause global warming. At a quantitative level, the details of their reasoning are likely beyond my ability to either confirm or dispute. It would surprise me, however, to learn of the existence of an analysis that includes all non-negligible thermal transfer phenomena (conduction, radiation, convection, evaporation, etc.) over a rotating oblate spheroid with an uneven surface where the surface and atmospheric gases are heated unevenly (i.e., different rates of heat absorption as a function of location on the surface). In fact, don’t GCM models attempt to do the analysis, and aren’t they continually be adjusted to agree with new temperature measurements as they become available?
To Mike McMilllan (July 21, 2012 at 7:11 am). If the blanket you add contains tubes through which water is pumped to a radiator in the room, yes I do think the blanket adds thermal mass and will make you cooler.
To MikeB. (July 21, 2012 at 3:52 am). I don’t believe I said an air-cooled engine cools by blocking radiation. On the contrary, an air cooled engine cools despite the fact that the cooling plates absorb energy radiated from the engine’s original surface and re-radiate some of that energy back to the engine’s original surface. To me, this behavior is comparable to the claim that greenhouse gases in the Earth’s atmosphere absorb some of the surface outgoing radiation and re-radiate some of the absorbed energy back to the Earth’s surface. If the latter always produces an increase in the Earth’s surface temperature, why doesn’t the former always produce an increase in the temperature of the engine’s original surface temperature? The other issue is what happens to the temperature of the radiating plates, which corresponds to what happens to the temperature of the atmosphere. I believe that under some conditions, adding additional material to the plates will reduce the plate temperature. Thus, it doesn’t seem unreasonable to think that increasing the amount of greenhouse gas might reduce the atmosphere temperature.
To Arthur (July 21, 2012 at 4:37 am). I’ll stipulate that the “the quote I dug up is from an educational website aimed at schoolchildren.” And that “more detailed analyses have been [being] published in the scientific literature since Victorian times?” My questions to you are: Who exactly are the AGW alarmists trying to convince when they say greenhouse gases heat the Earth’s surface and that heating will lead to impending doom, scientists or the general public? And, if you’re trying to convince scientists in the field, why make simple arguments at all? I believe the primary goal of the AGW alarmists is to convince government officials (i.e., people in power) that the world is coming to an end and we’d better get on the ball. From what I’ve seen of politicians (e.g., Senator Barbara Boxer), I’ll take schoolchildren over politicians any day. Simple arguments, which I believe are at best incomplete, are used to convince the general public, who in turn it is hoped will then put pressure on the powers-that-be to implement the AGW alarmist solutions. Fair enough. By the same token, I get to present simple scenarios that seem to contradict the simple arguments. See, I do believe in my own ignorance. I also believe in the ignorance of the general public; and will continue to point out the potential flaws and/or contradictions of “simple arguments” used to sway the general public.
To JeffC (July 21, 2012 at 5:15 am). Under what conditions does the presence of greenhouse gases in the Earth’s atmosphere quit “slowing-down outgoing radiation?” I ask this because if the outgoing radiation is “slowed down” for all time, then doesn’t thermal energy accumulate within the Earth/Earth-atmosphere system for all time? Wait you say, at some point the temperatures of the Earth/Earth-atmosphere system will rise to levels where the rate energy leaves the system is the same as the rate energy enters the system. Fine, at that point “no slow-down in the rate radiation leaves the Earth” exists. But didn’t your statement imply greenhouse gases slow down radiation? The greenhouse gases haven’t gone away; and as long as they’re present, don’t they slow-down outgoing radiation. So back to my question to you, Under what conditions does the presence of greenhouse gases in the Earth’s atmosphere quit “slowing-down outgoing radiation?”
To Jeremy (July 21, 2012 at 6:09 am) who wrote: “This is a most baffling, confused post which conflates many things and adds nothing.” Ah the human condition. Some things baffle me, some things baffle you. Maybe what I wrote is baffling; but if so, I’m not sure I’d take the word of the bafflee.
Eli Rabett says:
July 21, 2012 at 5:39 am
What happens is that effectively GHG block radiation from reaching space across most of the IR.
This includes IR emitted from the GHGs low in most of the troposphere.
Increasing concentrations of GHGs raises the altitude that GHGs can radiate to space in the blocked regions of the spectrum
Because of the lapse rate, the higher you go in the troposphere, the lower the temperature
This slows down the rate at which the Earth emits to space because it is now radiating at higher, colder altitudes
To maintain radiative balance (sun in, IR out) the entire Earth system warms until the temperature rises enough in the mid troposphere to restore the balance.
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What an absurd explanation.
The modern warmism scare is not about “the entire Earth system”, it is about the air temperatures near the surface (2m). Your “increasing concentrations of GHGs raises the altitude that GHGs can radiate to space” gives no additional energy to the surface hence the air near the surface can not get additionally warmer. This is that easy. I hope you know that that the surface warms the air by conduction and convection, so no additional warming of the surface – no additional warming of the air close to the surface. Or reduced cooling, whatever, the point is clear.
I find it hard to believe that increasing CO2 will significantly increase the ‘effective’ altitude at which energy is lost to space.
CO2 is not a major component of the atmosphere, the higher the ‘altitude’ the greater the amount of CO2 needed to increase the altitude, the ‘altitude’ at which energy is lost to space would have depth and that depth would be affected by concentration gradients. (There would be reduced density at increased altitude and a subsequent increase in the effective depth at which energy is lost – i.e. energy would still be lost from lower and warmer altitudes).
Konrad says:
July 21, 2012 at 6:11 am
Outgoing IR radiation radiated back to the Earth’s surface could slow the radiative cooling of surface materials.
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Yes, this is a notion the warmists like very much, but the problem is they can not prove it. I very patently asked them to present a link to a real scientific experiment proving that notion, but they failed (http://wattsupwiththat.com/2012/06/22/a-response-to-dr-paul-bains-use-of-denier-in-scientific-literature/). Does not look well for the concept.
Reed Coray, I have some sympathy for you trying to come up with novel ways of looking at this subject but I still agree with what Eli Rabbet, Joel Shore and some of the other posters have said about the GHG mechanism. On the other hand, most discussions on the subject seem to ignore the elephant in the room, so to speak. That elephant being the major portion of our atmosphere being the non GHG’s, nitrogen and oxygen.
The major constituents of our atmosphere are non-GHG gases with trace GHG’s being the secret sauce added to the bulk of non-GHG’s that enables the lapse rate structure of our atmosphere. GHG’s in the lower troposphere absorb LWR and due to the atmospheric density (mean time between molecular collisions being much less than the time a GHG gas molecule remains in an excited state), the absorbed energy is thermalized. So the bulk non GHG’s which do not radiate appreciably at normal temperatures are the medium of storage and transport of the heat energy apprehended by the GHG’s, The bulk non-GHG’s are the working fluid in the great thermal engine. The thermalized energy is transported to the upper troposphere by convection, the lapse rate structure being a manifestation of convection.
In the upper troposphere, GHG’s perform a predominantly emissive function. The transition from the absorptive to emissive function occurs when the density of the bulk atmosphere (not the GHG density) is such that the GHG absorption re-emission time is less than the mean time between molecular collisions. In other words, where the GHG’s are able to freely radiate to space the energy carried by the non-GHG’s.
I bring this up to emphasize that our earth’s surface temperature is a function of the earth’s atmospheric mass with GHG’s a necessary trace constituent. So when the concentration of the trace gas CO2 increases, the increase has only a miniscule effect on the height of the tropopause since it is predominantly the bulk atmospheric density that determines at what altitude GHG’s are able to radiate to space. If CO2 is the “control knob” for temperature as certain scientists have averred, then that control knob is logarithmic and there is little temperature to be gained in cranking it up.
Note also that one observes similar lapse rate structures in the Jovian and Venusian atmospheres at altitudes where atmospheric pressures are are in the range of earth’s tropospheric pressures. Yet the Jovian and Venusian atmospheres have very different atmospheric makeup both in greenhouse and non-greenhouse gases than earth’s atmosphere. I think this is a major clue that atmospheric bulk density is the major factor in earth’s climate and temperature regime with non-condensing GHG’s playing a necessary but not controlling role.
This is why I can give some credence of up to about 1C warming for a doubling of CO2 but consider the concept of amplification by water vapour or other positive feedbacks to be bogus. CO2 is a spent forcing, there is almost no warming to be eked out no matter how much coal or oil we burn. Man has little hope of averting the next ice age, either.
Thanks Anthony, a provocative post and an interesting discussion.
Arrhenius estimated that a halving of CO2 would decrease temperatures by 4-5°C and a doubling of CO2 would cause a temperature rise of 5-6°C. In his 1906 publication, Arrhenius adjusted the value downwards to 1.6°C (including water vapor feedback: 2.1°C). Recent estimates from IPCC (2007) say this value (the Climate Sensitivity) is likely to be between 2 and 4.5°C. But Sherwood Idso in 1998 calculated the Climate Sensitivity to be 0.4°C, and more recently Richard Lindzen at 0.5°C. Roy Spencer calculated 1.3°C in 2011.
I will try to make a model for the mind for those steadily repeating about thermos flasks and interpretations of laws of thermodynamics, bearing in mind rgb’s: “I may be wrong”. Imagine two similar and parallel metal planes 1 and 2. Number 1 is connected to an energy source and is radiating energy, let’s say 1000 watts, but in very short pulses each second i.e., 1000 Joule per second and only in one direction, against 2 which receives all the energy. The distance between the planes is half a light second. (Just to make it simplistic clear.) Plane1 emits a pulse against 2 which immediately absorbs the energy and reradiate (or repulsing) in both directions, one straight back to 1 and one out on the other side. This means that 500 Joule goes in each direction. Plane 1 receives, absorbs and reemits this energy in the same moment as it emits its second pulse of 1000 watts, which means it literally emits 1500 watts. This is once again absorbed and emitted in both directions from plane 2, 750 watts in both directions, which leads to a third radiation of 1750 watts from plane 1. Will it add up to infinity? No. It is an infinite geometrical progression: 1 + ½ + ¼ + 1/8… ((1/2)^n) and so on, but it has 2 as a limit. So, Plane 1 will end up emitting 2000 watts because of a feedback process between 1 and 2. Number 2 will also radiate the same but halved for both sides, so 1000 watts will go out of the system. Energy in = energy out. Have energy been created? No, the redirecting process of getting the energy out of the system has just delayed the transport so to say and made plane 1 warmer.
What if we add a third plane? If energy in = energy out, the third plane also has to emit 1000 watts out of the system from its outer side. But that means 1000 watts in both directions, in (back to 2) and out. This means that it actually emits 2000 watts. And to do so it has to receive 2000. That means that plane 2, which also radiates in both directions all together must radiate 4000 watts, which it must receive from plane 1 and 3 in this feedback process. And 1 will end up radiating 4000 watts. Another geometrical progression, but now as 1 + 2 + 4 + 8 +.. (2^n) where 1 is the outer plane and, let’s say 8, is “the ground”. Not so easy to grasp. It seems to be a bit like the hen and the egg, but this actually has a locigal solution
And this last example is what happens between different layers in the atmosphere as far as I have understood. The difference is of course that just a small fraction of the outgoing longwave radiation is absorbed by the adjacent layer. But still this process is surprisingly effective, at least in theory. The US Weather Service has a presentation of an earth radiation budget where 46% of the incoming radiation is absorbed by the surface. In the transformation 7% is sensible heat transfer, 24% is latent heat transfer, and 15 % is long wave radiation. Out of the last 9% is radiated directly to space, and only 6 % is absorbed by the atmosphere. Out of let’s say 240 w/m^2 this is about 14 watts. In a feedback process this would be enough to make the famously 390 watts that creates the 15C surface temperature through 15-20 layers of atmosphere with a reasonable amount of absorption from the GHG. But if this (which it of course isn’t, there is a convection) process alone should be responsible for the temperature upwards it would drop very quickly. The radiative laps rate is very high in the start and is far from linear. But there has to be some sort of additional radiation starting from higher altitude as well because of convection and directly absorption by the atmosphere of incoming energy. But does it happen this way?
This is a layman attempt of understanding, and instead of reading the same misinterpretations over and over again I should really like to read a post here on WUWT where these problems were addressed as comprehensive as possible, based upon an atmospheric model, and not some kind of more or less good parallel. SoD has a lot convincing about radiation, but more that it exists, and less about what I have mentioned here.
This doesn’t mean that Reed Corays post here is not interesting. I think I have read somewhere that on Neptun, the GHGs have a cooling effect, but I should have liked to have a good “traditional reference” before the alternatives are launched.
joeldshore: ” And, amongst the larger physics community, there is not only acceptance of the greenhouse effect but generally acceptance of the danger of AGW, as evidence by such things as the American Physical Society statement on climate change, the fact that the two textbooks that we use at RIT to teach introductory physics both discuss AGW, etc., etc.”
Well sure. If the earth is burnt to a crisp, then it would dangerous. Who wouldn’t agree with that? If the Rapture is tomorrow, then it would be dangerous not to be baptized today.
Now what’s your opinion?
Reed Coray says:
There is something important that you are missing here: The simple arguments that are presented to the public may be vast simplifications but they have underlying them much more complicated and detailed calculations that back up the basic conclusions. Your arguments on the other hand have nothing to back them up.
You seem to somehow be trying to say that because the scientists don’t present the public with thousands of lines of radiation code to explain the greenhouse effect but instead simple explanations, the simple explanations that you come up with that lead to very different conclusions are just as valid scientifically. I hope you can see the obvious flaw of such a notion.
Sleepalot says:
July 21, 2012 at 4:27 am
Show us what equations you are using. Or refer to my page for some ideas.
http://mc-computing.com/Science_Facts/Blackbody/Blackbody_Equations.html
Typically, most people who have problems don’t realize that the equation must be integrated!
Greg House says:
As Eli explained, the increasing greenhouse concentrations create a radiative imbalance that gives additional energy to the entire system. How that energy then gets distributed within the system is a function of the various processes that move energy around, with convection playing a dominant role in the troposphere as you have noted. In particular, since to a first approximation the average lapse rate in the atmosphere is expected to remain roughly constant (at some average between the dry and moist adiabatic lapse rates), if the temperature at a certain altitude rises by 1 C then the temperature at the surface will also rise by 1 C.
To a better approximation, there is expected to be a slight decrease in the lapse rate with increasing temperature because the lapse rate in the tropics tends to closely follow the moist adiabatic lapse rate which decreases [in magnitude] with temperature…iIe., the tropics are expected to warm more at altitude than at the surface. This is reflected in all of the climate models as the lapse rate feedback, a negative feedback. You seem to be proposing that things will warm at altitude without the surface temperature increasing at all, i.e., that the lapse rate will dramatically decrease in magnitude with temperature. However, there is no reason to expect this and no evidence that the warming is occurring in this way; if anything, there has been a discrepancy with the data showing LESS, not more warming, at altitude relative to the surface than is expected (the so-called missing “hot spot”), something that AGW skeptics have made much of (and with some serious misstatements of both the definitiveness of the data and the meaning of the discrepancy). So, it is interesting to now see skeptics such as yourself now apparently claiming that the data is so far wrong that in actual fact things deviate from the models strongly in the OTHER direction than the current discrepancy.
Furthermore, since much of the same physics controls the lapse rate feedback and part of the water vapor feedback in the climate models, models that have a larger (in magnitude) negative feedback from the lapse rate also tend to have a larger (in magnitude) positive feedback from water vapor, so that the uncertainty in the sum of these two feedbacks tends to be considerably smaller than the uncertainty in either individually.
So, to make a long story short, yes, it is to be expected that the surface will warm as the troposphere at higher altitudes warms.
Sam Yates says:
July 21, 2012 at 1:42 pm
Quoted from the end of your comment:
” … Quite frankly, this is embarrassing.”
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The discussions on this thread have been excellent IMO. It is likely very embarrassing for any of the believers in the CO2 arguments produced by the team. I’m not sure if your embarrassment was that or of your ending comment itself.
Maus says:
That is not what I was saying. What I was saying was that the statements by the APS and the textbooks represent the general conclusion of the physics community that the science behind the notion that temperatures will rise as a result of the anthropogenic enhancement of the greenhouse effect is solid, a conclusion that I agree with.
I used to wonder how people could wind up believing in witchcraft, blood letting, ghosts, goblins, and other manner of superstitious nonsense that could be so easily debunked by the slightest investigation of the facts combined with a bit of logic. Reading this thread I realise people still cling to superstitious nonsense in the face of facts and logic, all that has changed is the nature of the superstitions.
Thanks to rgb and joeldshore and even Eli (despite his pompous reference to himself in the 3rd person) and others for injecting some sanity into the discussion. Hopefully some of the readership will be prompted to pick up actual text books, learn to understand the calculus and the laws of physics to the point that they can apply the formulas for themselves instead of quoting drivel from web sites that throw terms around and explain away issues that for anyone who has bothered to understand the formulas and how to apply them is nothing but superstitious nonense.
Robert Austin says:
(1) I don’t think it is predominantly the bulk atmospheric density that determines this. Pressure broadening is important but the optical path length is also determined by the concentration of the greenhouse gases themselves. The effect of an increase in CO2 basically is what it is…Are you disputing the radiative calculations that have been done on this?
(2) A logarithmic dependence does not really mean that “there is little temperature to be gained in cranking it up”. It does mean that the temperature with concentration increases more slowly than linearly but it does so in a simple way already accounted for by climate scientists, e.g., it means that if the concentration has to double from 280 ppm to 560 ppm to produce a 3 C increase then it would have to double again to 1120 ppm to produce the next 3 C increase. It is why scientists talk of the sensitivity for doubling CO2 rather than the sensitivity for increasing it by, say, a constant increment of 100 ppm.
Frankly, Robert, I find your post here rather puzzling. You spend several paragraphs making all these statements casting doubt on the radiative effects of CO2. Then, in the end, you seem to admit that you agree with the consensus calculation of what the radiative effect of CO2 alone would do (warm things about 1 C if CO2 concentration doubles) but say that you don’t believe in the feedbacks magnifying that. Then you finish up with a final sentence that seems to go back to casting doubt about the conventional view of the forcing due to CO2.
I can’t figure out what sort of coherent argument you are even trying to make. Why don’t you try to very specifically explain to us what part of the conventional science you agree is correct and which part you don’t?
davidmhoffer says on July 21, 2012 at 12:56 pm:
“O H Dahlsveen;
By the way, sarcasm becomes no-one
>>>>>>>>>>>>>>>>.
If Einstein was around to respond to your last diatribe he most likely would have used that classic quip “that’s not right, that’s not even wrong”.”
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You’re guessing again davidmhoffer.
But since you are mentioning Einstein, think of this; “a man is initially moving along steadily at 4 miles per hour (4 mph). He then begins to increase his speed – by the time he reaches 16 mph he has quadrupled hi speed. You may say his speed is now; 4*4 or 4² mph.
However, our Albert has given us an energy equation i.e. E=mc², where E is (=) energy, m = mass and c is supposed to represent the speed of light.
So what is Einstein who believed, and went on to prove, that nothing can travel faster than light, trying to tell us?
As far as I am concerned c² = the speed of light squared is not only not possible, just like your EM radiation idea, but it is also likewise quite useless.
– Unless, of course, Einstein was trying to tell us that we will never work out what E for energy really is. – And that is what I think he did.
Think for yourself davidmhoffer, do some experiments and tell us about your own conclusions. Some parrots can utter human words, but do they therefore think like humans?
Do the simplest experiment experiment possible davidmhoffer. Do the experiment indoors where the air is still and ambient temperature is more uniform. – Take a piece of, say plywood, paint it matt black and lay it on the floor – you now have the very best absorber of IR radiation laying down there. Invert and suspend a hotplate, one that gives off IR and not red radiation, approximately one meter(1m) above the “ideal absorber of IR” and line it up precisely with the piece of black plywood. Measure the temperature (T) of the matt black absorber. Turn the hot-plate on and watch T increase dramatically.
If matt black plywood T does not rise, then I- if I were you – would reject the back radiation from GHGs six miles up theory all together.
joeldshore says:
July 21, 2012 at 3:14 pm
As Eli explained, … … So, to make a long story short, yes, it is to be expected that the surface will warm as the troposphere at higher altitudes warms.
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He did not say that, so your long story misses the point and obfuscates the matter.
That narrative of his I referred to in my previous comment is only designed to avoid the embarrassment of the main “back radiation” concept of warmists. Like I said, no additional warming of the surface – no additional warming of the air close to the surface. This is a high school level stuff.
joeldshore says:
July 21, 2012 at 3:17 pm
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If a conclusion is wrong but published in a book, then does that make it right? I guess that the use of that as a textbook was done by consensus. Specifically, by whom and when?
There is a lot more focus now on the so-called ‘science’ consensus of the past. The future’s greatest skeptics will arise from learning that the textbooks were wrong. Actually today’s greatest skeptics arose from learning that the consensus was wrong. Whether in the form of a textbook or a press release, saying it, writing it, or by consensus doesn’t make it so.