Discussion > How Simple Physics Demolishes the "Greenhouse Effect".
JFFO
Martin A
The trouble, jolly, is that extraordinary claims require extraordinary evidence. And we've had umpteen threads on here where someone or other is claiming radiative theory is wrong, and we've spent hours of time, and pages of discussion where we look into it in great detail and jaw over where it is wrong and attempt to look at the theories with a sceptical eye. Some actual real physicists have chimed in. None of the candidate theories have been convincing 'demolitions' of GHE. Not yet.
So when you say that we have to read into this one before dismissing it, then I say that wolf has been cried too many times. You may say this is unfair. I say spending hours of my precious time explaining physics to people who could quite easily get it from a physics textbook but who seem unable or unwilling to do so, is unfair. Life isn't fair.
So if this next great demolition theory is actually the one which rewrites the physics textbooks, then I'm afraid you will have to sell it to me, PDQ, because I've wasted enough heartbeats finding the flaws in such demolitions before.
TheBigYinJames
"extraordinary claims require extraordinary evidence". I'll drink to that. There are so many different definitions of the so-called atmospheric "greenhouse effect" that it is difficult to know what it is and thus what extraordinary evidence there is to support the effect.
Phillip Bratby
Phillip - here is my own definition. Do you see any problem with it?
The so-called greenhouse effect is the effect where the surface temperature of a planet whose atmosphere contains gases that interact with IR radiation is higher than it would be if the same planet had an atmosphere containing only gases that did not interact with IR - nitrogen, for example.
[Obviously there are criticisable points such as 'surface temperature' being a vague concept and the fact that, if you changed the atmosphere of a planet, it would no longer be the same planet. Even the assumption that it has a surface.]
Martin A
Marin: You would be defining a planet that also had no water and no clouds. The planet would heat up because the only way it could cool would be by direct IR from the ground. I would imagine that the atmosphere would start to disappear out to space. I do believe that people have looked at what would happen in that situation.
To me, talk about a greenhouse effect is wrong. What we have is a planet with an atmosphere that cools the surface by convection and evaporation. The atmosphere is cooled by IR radiation to space from clouds and IR active gases and the surface is also partly cooled by direct radiation to space. It is just a "simple" heat transfer situation that should be solved by the normal methods of solution of all the equations of heat transfer and fluid flow, in 3-dimensions and over time . There is no need to define a greenhouse effect - it is just a bit of propaganda to fool people into thinking that here is a unique phenomenon that humans are interfering with. What happens is just bog-standard heat transfer and fluid flow.
Phillip Bratby
What happens is just bog-standard heat transfer and fluid flow.
Yes, of course.
Martin A
Watts addresses the transfer of heat energy from cooler to warmer objects.
http://wattsupwiththat.com/2013/05/28/slaying-the-slayers-with-watts-part-2/
http://wattsupwiththat.com/2013/05/27/new-wuwt-tv-segment-slaying-the-slayers-with-watts/
rotationalfinestructure
How many times have we had this canard of "heat energy cannot flow from colder to hotter objects" which is patently and demonstrably false. It's said by people who fundamentally misunderstand the idea of energy flux. Both myself and Martin and others have described why it is wrong in immense detail using a variety of analogues for the hard of physics to understand. But it has no effect. Wrongheadedness and dare I say stupidity masquerades as free-thinkers and revolutionaries. I've tried and tried.
But like herpes, no matter what you do, it keeps coming back.
I'm starting to think it's a sort of mathematical dyslexia, beloved of a certain type of person who confuses their own inability to understand a concept with the truth of that concept.
It must stop.
TheBigYinJames
TBYJ
Perhaps sites like this, first one on a Google search should be put right?
http://electron6.phys.utk.edu/101/CH7/Heat%20Flow.htm
Without an external agent doing work, heat will always flow from a hotter to a cooler object. Two objects of different temperature always interact. There are three different ways for heat to flow from one object to another.
Personally I'm overly interested in this discussion, but having a go a posters here when most educational sites will at best say something like
The Stefan-Boltzmann law tells you how much energy is radiated from an object at temperature T. It can also be used to calculate how much energy is absorbed by an object in an environment where everything around it is at a particular temperature :The net energy change is simply the difference between the radiated energy and the absorbed energy. This can be expressed as a power by dividing the energy by the time. The net power output of an object of temperature T is thus:
We've looked at the three types of heat transfer. Conduction and convection rely on temperature differences; radiation does, too, but with radiation the absolute temperature is important. In some cases one method of heat transfer may dominate over the other two, but often heat transfer occurs via two, or even all three, processes simultaneously.
doesn't seem to be a good way of going about convincing people.
SandyS
SandyS,
I take on the point that shouting at people doesn't usually lend itself to convincing them... but....
This isn't the first time. This discussions thread area is littered with the debris of discussions where we have quietly and gently rebuffed the various alleged 'demolition' theories about regarding pressure, temperature, the laws of Thermodynamics, black body radiation, experimental truth, measurements, thought-experiments... etc etc ad nauseam.
I have personally spend many hours, along with others here, trying to help out people rather than lambast them. but what good has it done? People don't even have to go to independent physics sources now, the explanations are all here, one or two clicks away from the front page. If the explanations are not convincing, them it is not OK just to say you are not convinced. Vague feelings of uneasiness are not the same thing as finding a fault. At some point when a person has no more logic to argue against my explanations, they either have to accept that I am right or else they don't understand it. If I was wrong, they would be able to find a flaw in my logic, but there isn't one.
But that's not what happens. When the logical argument reaches a conclusion they do not emotionally like, then the goalposts get changed, simplifications in the analogy I am using to demonstrate a relationship get pointed out as fatal flaws, or name-calling starts, ad-hominems, appeals to he authority of whoever wrote the offending article. etc.
At no point has anyone on these threads ever thrown the towel in and admitted they had it wrong. It's a form of stubbornness which is as admirable as it is deadly to logic. For every 20 or 30 hours I've spend constructing arguments and analogies to demonstrate where they have gone wrong, you will find the proponent moving on to another thread, with exactly the same name, in the vain hope I will have gotten bored or gone away. If I'm wrong about anything I've said, point it out to me and I will admit it. But it never happens. They assume the doublethink position of having been argued to a logical standstill but YET still clinging to the hope that it's all wrong.
That's why I get annoyed.
And as you point out, it doesn't help that many science communicators, in an attempt to simplify a mathematical scientific domain problem, will use language in a way which can imply something completely different to the lay reader. Examples of these are 'greenhouse effect' and the 'heat cannot flow from cold to hot' and 'back-radiation', none of which describe what is actually going on - all of which are arithmetical sums of vector properties. All of which suggest a physical process which seems nonsensical.
Saying 'heat cannot flow from cold to hot' is a slack, messy, inaccurate way of saying that the net flow of energy is always from hot to cold. It is not saying that heat energy does not flow in both directions, which it quite obviously does. it is not saying that the hotter object cannot be at any time after the start of the experiment hotter than it would be if it was just left to cool on its own with no cool object nearby.
In some ways its counter intuitive, but it's not that hard to grasp. People who cannot grasp it suggest to me wilful ignorance.
TheBigYinJames
I'll change my user name to Zoster and apologise for my innumeracy. Later
BigYin
To pick up a comment from Unthreaded:
The real pity of this site is that it attracts people who do not understand physics who like to lecture those of us who do understand physics how close-minded we are. You make us look stupid.The real pity of this thread (though I wouldn't phrase it quite like that) is that it attracts people like a couple of pals of mine from school.
Very bright, both with top marks at A-level Physics; one went on to be more than competent in his field (though not a household name), the other I lost touch with.
Both totally incapable of understanding that 90% of the human race are not interested and need anything to do with physics reduced to words of one syllable. So the average layman "knows" that if you put a warm object next to a cool object the warm object will get cooler and the cool object will get warmer till both are at the same temperature as their surroundings.
You can argue the physics of that activity till you are blue in the face. As far as the average layman is concerned hot flows to cold which is — in effect — what it does. Yes?
You get pissed off because people (like me?) use layman's language to describe phenomena.
People (like me?) get pissed off because we're trying to make sense of the world about us and you're more concerned with the technicalities of what happens than with the end result.
{Perhaps at this stage I ought to point out that "you" is not meant to be taken personally!}
People (like me?) also have to face the problem that "our" scientists are every bit as reluctant as the Climateers to listen to hypotheses that don't fit their belief system.
So you insist on clinging to the "greenhouse effect" even though we all know that is a misnomer and every paper that comes out of (eg) Principia Scientifica is sneered at every bit as much as the climate activists sneer at the GWPF output.
"It has to be CO2" for us every bit as much as for them in spite of various papers from various sources arguing otherwise. Rightly or wrongly? We don't know, because the minute anyone says "it's not CO2" or "it's not back radiation" the blinds come down and the mind switches off.
So, humour us laymen, BigYin, just once more.
Let's stick to a couple of simple points.
1. What basic physics has Casey got wrong?
2. He produces a well-argued (to my mind) case that we don't need a "greenhouse effect" to account for the state of the earth's climate. Where does that case fail?
3. And remember, this is for laymen! Pretend I'm Ernest Rutherford's famous barmaid!
SandyS
A timely quote!
Gunning Fog Index: 16.48. Anything above 12 is considered as university standard!
Mike Jackson
"...Convection transfers heat via the motion of a fluid which contains thermal energy. In an environment where a constant gravitational force F = mg acts on every object of mass m, convection develops naturally because of changes in the fluids density with temperature. When a fluid, such as air or water, is in contact with a hotter object, it picks up thermal energy by conduction. Its density decreases. For a given volume of the fluid, the upward buoyant force equals the weight of this volume of cool fluid. The downward force is the weight of this volume of hot fluid. The upward force has a larger magnitude than the downward force and the volume of hot fluid rises. Similarly, when a fluid is in contact with a colder object, it cools and sinks. When a volume of fluid such as air or water starts to move, the surrounding fluid has to rush in to fill the void. Otherwise large pressure differences would develop. This sets up a convection current and the looping path that follows is a convection cell. Since fluid can not pile up at some point in space without creating a high-pressure area, it will flow in a closed loop.......Nuclei and electrons are charged particles. When charged particles accelerate, they emit electromagnetic radiation and loose energy. Vibrating particles are always accelerating since their velocity is always changing. They therefore always emit electromagnetic radiation. Charged particles also absorb electromagnetic radiation. When they absorb the radiation they accelerate. Their random kinetic energy increases. In thermal equilibrium, the amount of energy they loose to radiation equals the amount of energy they gain from radiation. But hotter objects emit more radiation than they absorb from their cooler environment. Radiation can therefore transport heat from a hotter to a cooler object...."
Gosh - at last a clear explanation of the basic physical principles of heat transfer.
Martin A
Here is another paper to consider; what is wrong with this ?
http://principia-scientific.org/publications/New_Concise_Experiment_on_Backradiation.pdf
Ross Lea
...1. What basic physics has Casey got wrong?
...
Dec 1, 2015 at 2:52 PM Mike Jackson
Mike, I find it painful to read his stuff in any case.
But whenever I'm trying to read something technical, as soon as I come across one single significant misconception in basic physics, that tells me there is no point reading further.
He says "...has successfully obfuscated the weakest and most important part of that proposition. Namely, that terrestrial heat radiated into the atmosphere is there absorbed and re-emitted back to earth to raise surface temperatures beyond what is possible from the incident radiation alone..."
The misconception I put in bold means that there is no point, as BYIJ said, wasting further heartbeats reading the rest of what he says. As I said to JF, he takes a dodgy wrong explanation of the GHE and then proceeds to say that, because it's wrong, the GHE does not exist.*
If you start from first principles, switch on the Sun, and work out from first principles what happens as the Earth warms up to its equilibrium state, you find that all (ALL!) the heating is done by incoming radiation from the Sun.
It is perfectly true that some "terrestrial heat radiated into the atmosphere is there absorbed and re-emitted back to earth". However just means that some energy that arrived from the Sun did not escape back out to space at the first attempt. So the Sun's incoming radiation continues to warm the Earth until finally, the total radiation that *does* make it back out to space, both from the ground and from the atmosphere, balances the incoming solar radiation.
*It's standard Dragon Slayer stuff: (1) Give an incorrect explanation of the GHE (2) Point out that it's nonsense (3) declare that therefore the GHE does not exist.
Martin A
Ross Lea - same as the above.
Martin A
I'm not doing it Mike. I can tell you it will be one of the following:
1. Casey has got it wrong, inadvertently and earnestly, and is claiming something that is not true.
2. Casey has described the correct physics in a way that implies something else to the lay reader.
3. Casey is correct and physics must now be overturned
As a courtesy, I read the abstract, and here are my thoughts
This article explores the "Greenhouse Effect" in contemporary literature and in the frame of physics, finding a conspicuous lack of clear thermodynamic definition.
Unfortunately for him, the greenhouse effect, no matter how ill-named, is defined completely understood. If he was unable to find a definition of it then he should visit the discussion section of this very blog.
Then this:
However, since the composition of a body, isolated from thermal contact by a vacuum, cannot affect mean body temperature, the "Greenhouse Effect" has, in fact, no material foundation.
Which is nonsense. The greenhouse effect does not affect the mean body temperature of the earth and nor has it ever been argued to have done. The mean temperature of the earth (as a whole unit) is determined completely by the solar insolation, as he says isolated in a vacuum it cannot be any other way. Earth must emit as much heat as it receives, so the temperature of the earth is determined completely by the sun.
But the greenhouse effect is not about the mean temperature of the earth as a body, it is only about the temperature differences between the components, and specifically about the temperature gradient between the top of the atmosphere and the ground. Remember that the average temperature of the earth is controlled by the sun, but the relative temperatures of the parts which make up this average (air and ground) can be wildly different from this mean value. The air is cooler than the ground, and the higher air is cooler than the lower air, thanks to the lapse rate.
If he misunderstands this incredibly basic concept, then this paper is doomed.
He compounds this error:
Compositional variation can change the distribution of heat within a body in accordance with Fourier's Law, but it cannot change the overall temperature of the body
And that is exactly what the greenhouse effect is saying. Not that the earth is warming up with the addition of greenhouse gas, but that the lower atmosphere is warming up in comparison with the upper atmosphere (which is cooling). The average of the two is still the same. To argue that greenhouse theory posits the earth is getting warmer is dishonest and is called a straw-man argument in logic. Either that or he has misunderstood it.
Then he tries to get meaty:
Arrhenius' Backradiation mechanism did, in fact, duplicate the radiative heat transfer component by adding this component to the conductive heat flow between the earth's surface and the atmosphere, when thermal conduction includes both contact and radiative modes of heat transfer between bodies in thermal contact
What he is trying to say here is that since "thermal conduction between earth and atmosphere" as a concept already includes both kinetic (or as he calls it, contact) and radiative modes, then there is no need for pesky Arrhenius to add another one called back-radiation. Watch the pea. Back-radiation is not from the earth to the atmosphere. It is in the opposite direction. So it is perfectly legitimate to add it into the mix, because it is a NEW amount of radiation, not previously included in the two modes which left the earth for the atmosphere.
If you give your son £10 a week by placing it on the dining table on a Monday morning, and every week your son decides to give you £5 back for his keep, and puts it on the dining table on Monday morning, then every week after the first one there is £15 on the table every Monday morning. Temperature is a measurement of the amount of energy bouncing through a cube of matter. It doesn't care whence it came.
And now the sleight of hand:
Moreover, the temperature of the earth's surface and the temperature in a greenhouse are adequately explained by elementary physics.
The coup-de-grace of the straw-man. We all know that the greenhouse effect is mis-named. Greenhouses work mostly by preventing convection. We all know this is not how the atmosphere works. But this dishonest gambit tries to conflate the two, if one is explained by simple physics, so is the other. Bad show. but is he doing is dishonestly, or an honest mistake?
A clue:
Consequently, the dubious explanation presented by the "Greenhouse Effect" hypothesis is an unnecessary complication
So here he's saying, not that it isn't true, but that it's an unnecessary complication, which is somehow dubious. This sentence is known as hedging your bets. The greenhouse theory is either correct or incorrect. It's not dubious, because nobody is doubting it (not with a scientific take-down anyway) and whether it is necessary or not is a completely unscientific discussion. This sentence is just a swipe at it, not a scientific statement. it's saying "I don't like it" I'm starting to believe he knows what he's doing.
And then:
Furthermore, this hypothesis has neither direct experimental confirmation nor direct empirical evidence of a material nature.
Which is nonsense. I'm not sure what the difference is between "direct experimental confirmation" and "direct empirical evidence of a material nature" so I expect he was just being tautological for effect. There are many experiments and measurements which prove IR radiation is coming back down from the atmosphere. Where does he think it goes?
And his "finisher"
Thus the notion of "Anthropogenic Global Warming", which rests on the "Greenhouse Effect", also has no real foundation.
Unfortunately he hasn't managed to demolish greenhouse theory, he's just told some fibs, made some mistakes, and conjoined some concepts which deserve to be separate. And then come to a lousy conclusion.
AND THAT WAS JUST THE ABSTRACT!
Sheesh!
TheBigYinJames
After having spent most of my working life in the energy industry, I was subsequently amazed how many people making policy and in the renewable energy industry didn't know thew difference between energy and power - and worse, didn't want to know.
After having spent a lot of time involved in heat transfer and fluid flow, I was subsequently amazed at how many climate "scientists" and others didn't know the difference between energy and heat - and worse, don't want to know. Net energy transfer by EM radiation goes from a hot body to a cold body - photons are bosons.
Phillip Bratby
The important word being net, which is an arithmetic sum, which says nothing about the sizes of the parts which made it up. Both hot and cold bodies are heating each other, the hotter one is just heating the cooler one much more than vice versa, so the NET effect is the hot one cools and the cool one heats. But there is energy both ways.
TheBigYinJames
Precisely. I had never heard of back-radiation and never considered back-radiation in all my work, because it didn't do anything - it is cancelled by exactly the same forward-radiation. So it should never be considered and anybody who considers it is being deceptive.
Phillip Bratby
TBYJ / MartinA
Sorry to have ruined your afternoon. ☺
I must be very stupid so I shall refrain from troubling you further.
Mike Jackson
As with Phillip Bratby, I was only considering the NET energy flow which must be from a hoter to a cooler body I except that interchange may take place.
Ross Lea
I mean accept of course before someone picks it up
Ross Lea
Martin A, TBYJ
Can I refer you to Rhoda Dec 1, 2015 at 5:10 PM unthreaded. That is exactly what I maintain.
Ross Lea
This is Rhoda's post referred to by Ross Lea
TBYJ, you may need to clarify your terms. RADIANT energy does what you say. Heat energy used in that context isn't really right. The exchange of radiant energy results in a change of heat energy always from hot to cold. If you know of any situation in which it goes the other way, net, you need to work out a way to market it.
The situation with the second law is simple but many misunderstand it in the context of GHE. The second law is not being broken. Net energy flow is always 'hot' to 'cold'. Only the rate of flow is slowed in the GH scenario. And that may be described as 'warming' although it really isn't. The entire effect is only to slow cooling. To make the night-time minimum a little warmer, a little later. To make the coldest times of winter less cold. That's why 'global warming' isn't scary.
I sometimes wonder whether the entire result of increased CO2 just delays the escape of heat for a few seconds or minutes.
Dec 1, 2015 at 5:10 PM | Unregistered Commenterrhoda
SandyS
Posted on Unthreaded.
http://greenhouse.geologist-1011.net/
Seems to me that Tyndall, Arrhenius and Fourier are at the heart of this.
From RR:
"Jolly Farmer: very interesting, with a lot to mull over. Odd how it more or less gels with much of what I have said, in my non-scientific musings."
From Martin A:
"From a superficial look, he seems to take dodgy explanations of the greenhouse effect, and, from their dodginess, conclude that the greenhouse effect does not exist. If I'm correct that that is his conclusion, he has to be put into the category "crank".
From me:
"RR, thanks for your reply.
Martin A, no thanks for this:
"From a superficial look, he seems to take dodgy explanations of the greenhouse effect".
No-one is obliged to reply. Anyone who does reply should base that on more than a "superficial look". And should not base that upon what the guy "seems" to be saying.
My enquiry is genuine. A desire to learn. "Seems to take dodgy explanations" is not very helpful."