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## Confusion over the Basics

Many people ask questions about some quite basic concepts. Which is wonderful.

I have introduced this page to capture the many articles on science basics and “alternative theories”.

Many of these articles reduce the “problem” down to the absolute simplest basics. That doesn’t mean climate science treats the subject as a simplistic problem – but the easiest way to demonstrate the flaw in a point of view is to consider the simplest model that demonstrates an error.

This section has a vague arrangement but from a visitor’s point of view is in no particular order – pick your problem and work from there..

The “Greenhouse” Effect Explained in Simple Terms – summarizing the effect, attempting to “make it simple but not too simple” with many links to other articles

### Physics and Thermodynamics Basics

Heat Transfer Basics – Part Zero – a few examples of heat transfer, simple stuff but often misunderstood.

Heat Transfer Basics and Non-Radiative Atmospheres – a few minor comments on “Heat Transfer Basics”

Sensible Heat, Latent Heat and Radiation – the relative importance of different components in the surface energy balance

The Dull Case of Emissivity and Average Temperatures – how “emissivity” changes with surface type or why the earth is really quite close to a “blackbody”

The Amazing Case of “Back Radiation” – Part Three – the radiation from the atmosphere, and why it is absorbed by the surface, see also Part Two on how we know it comes from the “trace gases” like CO2 and water vapor, and Part One on the actual values.

The First Law of Thermodynamics

Do Trenberth and Kiehl understand the First Law of Thermodynamics? – examines a very simple (non-climate) model to demonstrate a simple yet important principle. Temperatures inside a system can be much higher than the boundary temperature. And this doesn’t violate any thermodynamics laws. And Part Two –  small addition to Part One, showing the dynamic results of how equilibrium is reached.

Do Trenberth and Kiehl understand the First Law of Thermodynamics? Part Three – The Creation of Energy?

Do Trenberth and Kiehl understand the First Law of Thermodynamics? Part Three and a Half – The Creation of Energy?

Plus Interesting Refutation of Some Basics – as another blog explains why I have got it so wrong..

And not quite on the first law but a convenient place to park What’s the Palaver? – Kiehl and Trenberth 1997 – some basic comments on this simple paper which has somehow become a lightning rod for everyone unhappy about stuff to do with climate science.

The Second Law of Thermodynamics

A law very misunderstood..

The Real Second Law of Thermodynamics – explaining how entropy is calculated with a few simple examples. How entropy increases – in accordance with this law – when energy is transferred by radiation from colder to hotter bodies, as well as the reverse, so long as net heat transfer is in the right direction.

Amazing Things we Find in Textbooks – The Real Second Law of Thermodynamics – simple but necessary – pages from six heat transfer textbooks to confirm the stuff that so many people dispute.

Kramm & Dlugi On Illuminating the Confusion of the Unclear – Kramm & Dlugi step up as skeptics of the “greenhouse” effect, fans of Gerlich & Tscheuschner and yet clarify that colder atmospheric radiation is absorbed by the warmer earth..

Kramm & Dlugi On Dodging the “Greenhouse” Bullet – Kramm & Dlugi demonstrate that the “greenhouse” effect doesn’t exist by writing a few words in a conclusion but carefully dodging the actual main point throughout their entire paper. However, they do recover Kepler’s laws and point out a few errors in a few websites.

The Three Body Problem – a simple example with three bodies to demonstrate how a “with atmosphere” earth vs a “without atmosphere earth” will generate different equilibrium temperatures.

“Blah blah blah” vs Equations – a prediction that inappropriately-named “skeptics” of the “greenhouse” effect will not be able to produce an equation.

Absorption of Radiation from Different Temperature Sources – explaining how it is impossible that energy from lower temperature sources can’t be absorbed by higher temperature sources.

Intelligent Materials and the Imaginary Second Law of Thermodynamics and The First Law of Thermodynamics Meets the Imaginary Second Law– all continuing an in-depth look at the second law of thermodynamics

The Imaginary Second Law of Thermodynamics – looking at the “problem” from one point of view.

Radiation Basics and the Imaginary Second Law of Thermodynamics – considering this second law “problem” from the point of view of one question asked by a commenter.

The Sun and Max Planck Agree – Part Two – shortwave (solar) and longwave (terrestrial) radiation and how they can be easily distinguished.

Misc

The Hoover Incident – what the earth’s climate might be like if all of the gases like CO2 and water vapor were “hoovered up” so that the atmosphere didn’t absorb or emit any radiation

### Commentary on Alternative Theories

New Theory Proves AGW Wrong! – a guide to the steady stream of new “disproofs” of the “greenhouse” effect or of AGW. And why you can usually only be a fan of – at most – one of these theories.

Gerlich & Tscheuschner

Miskolczi

Lunar Madness and Physics Basics – a look at the effect of heat capacity of the moon’s surface on its temperature, and why average temperature can easily confuse.

On Missing the Point by Chilingar et al (2008) – a good demonstration of how to mislead people..

Things Climate Science has Totally Missed? – Convection

Paradigm Shifts in Convection and Water Vapor? – reviewing a paper that claims to show huge problems in the basic ideas of climate science on water vapor. A paper where, surprisingly yet helpfully, the author shows up to clarify his own lack of basic understanding of maths.

Venusian Mysteries – does the high pressure of the Venusian atmosphere (due to its huge mass) create the high surface temperatures?

Venusian Mysteries – Part Two – a more in-depth and technical look at Venus under certain artificial conditions

The Rotational Effect – why the rotation of the earth has absolutely no effect on climate, or so a parody article explains..

Water Vapor vs CO2 as a “Greenhouse” Gas – if only climate science had realized..

American Thinker – the Difference between a Smoking Gun and a Science Paper – comments on theAmerican Thinker article “The AGW Smoking Gun” – and following comments by the author – American Thinker Smoking Gun – Gary Thompson’s comments examined

### 38 Responses

1. […] of the surface for reasons that are a confused mangle of the second law of thermodynamics. See Science Roads Less Travelled and especially Amazing Things we Find in Textbooks – The Real Second Law , The Real Second Law […]

2. […] so many people on blogs around the internet believe this idea violates the second law of thermodynamics I thought it would be helpful to these readers to let them know to put Kramm & Dlugi 2011 on […]

3. By the way, as a suppliment to your excellent articles, are you aware of this experiment?

• Phil,

Thanks, I was not aware of it.

I wrote 2 comments there. My first disappeared. My second (shorter version) disappeared, but that time I kept a copy:

I wrote a long comment with many specifics about how this experiment write up was not clear.

Then I hit preview.

The comment disappeared.

Short version – The experiment writeup is not clear and as a result probably demonstrates nothing to people who are confused about heat transfer basics. Different descriptions for the same item. Text within the graphics cannot be read. Statements that are unclear. References to “earlier posts” that provide no link or actual reference. Etc.

So it could be a great experiment with a decent writeup..

• Comments work form me! even preview.
Please be as critical as you like .

If a problem then send an email to me be_very_careful[at]hotmaildotcom.
I will see if iI can update tonight

All posts should make it – no captcha I only delete spam or defamatory

• A difficulty with all laboratory level experiments is that they tell about the real atmosphere only trough theory. They are meaningful to those who accept the theory, but people who accept the theory know that all the required experiments needed to validate it have already been done. They know that a simple laboratory experiment may demonstrate the theory but not add significantly to the evidence.

Simple experiments have been proposed to prove a point by people who wish to convert skeptics. They never succeed as the skeptics are always free to dismiss the evidence as wrong or irrelevant, because they don’t accept the theory that might make them relevant.

The evidence for the present theories has been built on a huge amount of past experiments. The totality of that information is the proof. If that’s denied, then nothing can be done to convert a person who does not want to learn from standard sources and who dismisses all valid explanations.

Teaching is possible, because the students do mostly accept the content as valid and are willing to learn. That does not require that they are not critical. On the contrary being critical is required for reaching deeper understanding, but being critical is not the same as dismissing outright everything not understood immediately.

• on March 5, 2013 at 3:02 pm DeWitt Payne

Pekka,

The results of some experiments that confirm strongly held beliefs will be accepted no matter how poorly the experiment was carried out. A classic example of this is the 1909 Wood experiment. It’s extremely poorly documented and the results were rejected by no less than Charles Greeley Abbot in the same journal a few months later. Wood wrote a more detailed theoretical paper the same year, but it had a fundamental flaw which invalidated the result, as was pointed out in a rebuttal published shortly thereafter. And yet you find people quoting Wood as if he actually proved something about radiative transfer physics. One could only obtain the results he did if his boxes weren’t equally well insulated. That was actually inadvertently demonstrated by one of the Sky Dragon crowd recently.

• DeWitt,

People use all kind of arguments, but I don’t think that anyone is influenced by the Wood experiment. That applies both to skeptics, who are no more skeptics based on that experiment, and to to those who trust in main stream science, whose trust is not diminished the least by references to that paper.

• Pekka/DeWitt: The most convincing experiments are those whose results are not known at the time when scientists are debating which theory applies to an experimental situation or perhaps how theory should be applied.

Could someone who agrees believes radiation emitted by a cooler source is scattered, rather than absorbed, by a warmer surface collaborate with someone who believes in conventional physics to design an experiment which would unambiguously give different results depending on which theory was correct? Then could both parties carry out parallel experiments? Obviously both parties would want to be exceptionally careful in designing all aspects of the experiment, because the “winner” of the first experiment might be reluctant to agree to refinements or modifications for a second experiment which might change the agreed upon conclusion. Every time I design and carry out a experiment, I usually have a number of improvements I want to make in the second. In addition, there would certainly be a tendency to “cheat” by trying to perform the experiment before deciding whether or not an agreed-upon experiment will answer the question.

Some possible experiments are a modification of Wood’s experiment or an experiment to demonstrate whether pyrometers do or do not measure DLR.

At one time, there was a very vocal argument between several future Nobel Prize winners in chemistry concerning why certain reactions took place much faster than others. The establishment believed that the transition state energy for the fast reaction was reduced by electronic effects. The challenger believed that the transition state for the slower reaction was raised by crowding. The contenders eventually agreed upon new test systems and found that the crowding hypothesis explained rate differences in some cases. It didn’t resolve the debate about the explanation for the unmodified classic reactions; that was eventually resolved by observation of the intermediate, which had the structure anticipated for stabilization by electronic effects.

As best I can tell, the radical skeptics have too much invested in what seems to be their religion to act like real scientists.

• Frank,

Whenever a potentially important new theory or hypothesis is introduced it’s natural to search for experiments that can make a distinction between the new theory and the alternatives unless someone can point out earlier empirical data that’s conclusive enough without new experiments.

That’s as it should be. The “new” physical ideas that pop out in the climate debate belong, however, almost uniformly to those that have already been proven wrong by earlier experiments. That’s more or less unavoidable, if the ideas lead to significantly different outcome than the standard theory, because the standard physical theories have been so thoroughly verified over past decades.

By the above I don’t refer to all model results about the atmosphere, because the models are not accurate and may in some cases represent very badly the fundamental principles. The atmosphere ant the wider Earth system are complex and very much remains incompletely known and understood. It’s, however, virtually certain that all the fundamental laws of physics that are significant for these systems are known well enough and will not change in the future.

How radiation interacts with matter under conditions that are relevant for the atmosphere is known perfectly well and confirmed by a huge number of empirical observations. Nothing can change that. People tend to ask for the specific experiment that proves such claims as I made. That’s, however, not the nature of the empirical support for the best understood parts of physics. For these parts the evidence comes from the success in applying the physical knowledge successfully time after time and without a single confirmed contradiction. There must be rather tens of thousands or hundreds of thousands of empirical observations than mere thousands on the interaction of IR radiation with gases.

The huge HITRAN database is based on such observation while it contains also some additional data derived from models for lines that are not important enough to warrant direct empirical measurements. Much of the remote sensing work is based on the understanding of these phenomena and would rapidly lead to contradictory results, if the theory would be wrong.

Specific confirmatory experiments are usually done only at the early phase of understanding and rapidly superseded by the further development that has new goals either in science or in applications.

• Pekka wrote: “How radiation interacts with matter under conditions that are relevant for the atmosphere is known perfectly well and confirmed by a huge number of empirical observations. Nothing can change that.”

Speaking as the devil’s advocate, the response is: The fact that heat never flows from cold to hot is known perfectly well and confirmed by a huge number of empirical observations”. Radiation transfer is certainly heat. Your theory says that heat flows from cold to hot, contradicting the 2LoT. How does one decide which theory applies to this situation? Of course, the answer we both agree upon is that the 2LoT has been misapplied to this situation; it only applies to the net flux of radiation. What experiment has been performed or might be performed which unambiguously demonstrates that the 2LoT applies only to the NET radiative flux? Answering such questions makes us better scientists.

• Frank,

Looking for an experiment to confirm the right interpretation does not seem to the relevant way of approaching this issue as nobody really disagrees in a well defined way on the fact that the Second law is about the net flow of heat. Disagreeing on that is not a common skeptical argument either, and I doubt we can find anybody who could tell what a hypothetical disagreeing theory would predict. If nobody can provide an alternative prediction we have nothing to test empirically.

We have seen many comments where it’s claimed that radiation cannot proceed from a colder body to a warmer one at all, but that’s not presented in a way that leads to alternative predictions to test. Many people have accepted the correct formula for the net energy transfer, i.e. a formula where a difference of two terms is calculated, but denying that the two terms would represent radiative heat transfer that occurs in both directions. They insist, however, that the result is due to a reduction in the number of photons that transfer energy from warm to cold rather than an outcome of two fluxes that partially cancel each other. This kind of claims cannot be countered by measurements of heat transfer as they are correct on that.

We have also the claims that a colder body cannot influence the temperature of a warmer body at all, but these claims are typically presented for setups that cannot be brought to laboratory as they rely on having empty space in the background. When we start to introduce cold walls etc. we have new setups that need not be accepted as relevant.

My point is that we know the correct answers from the theory. The theory has been validated in many ways but not by exactly those setups that are brought up, because those setups cannot be created. Trying to introduce some equivalent setups is useless, because they are not really equivalent with best attempt. That brings us back to the situation that we have already tested the theory, and we know that it works. We cannot, however, prove anything to a person who has decided not to believe in the theory. We cannot do it with the help of any experiments either.

On this site we have certainly also readers who are willing to learn. My view is that the best way to help them is through introduction to the present best understanding of physics. All unnecessary complications should be avoided in that, but at the same the issues should be presented correctly without such shortcuts that make real understanding impossible and allow for justified criticism.

• Pekka: There are a variety of alternative explanations to disprove.

Some believe that upward and downward radiation partially “cancel” (as electric and magnetic fields do cancel). This can be addressed by measurements of the upward and downward flux, which show that they don’t cancel. The pyrometers normally used to make such measurements have been challenged, but there should be alternative instruments or possibly experiments to demonstrate that pyrometers actually measure what they were designed to measure. (This is beyond my scope of expertise.) Furthermore, if radiation is composed of waves, waves don’t cancel when two waves pass directly through each other. If radiation is composed of photons, the QED doesn’t produce cancellation either. If cancellation occurs because photons collide and annihilate each other, they wouldn’t repeatedly pass through each other.

Other believe that photons emitted by colder sources are somehow scattered when they have the opportunity to be absorbed by warmer objects (to prevent “violation” of the 2LoT), while photons from hotter sources are absorbed in the manner predicted by the object’s absorptivity. This hypothesis can be tested experimentally. (How about heating samples in an infrared spectrophotometer to see if their absorption disappears at high temperature? Warning, the IR source in a conventional IR spectrophotometer is electrically heated to 1000-1800 degC.)

You write: “The totality of that information is the proof”; a classic appeal to authority. You correctly point out that huge chunks of accepted physics will have to be abandoned if either of the above interpretations is correct. I don’t recognize presence of the type of irreconcilable conflict between theory and experiment that previously gave birth to such scientific revolutions. But when respected physicists say that “the universe may be stranger than we can imagine”, perhaps we should dispose of these hypotheses in the normal scientific manner, with scientific experiments that directly address the hypotheses. Unfortunately, IMO (and possibly yours), the skeptics who reject conventional radiation physics are thinking/behaving in a manner incompatible with normal scientific discourse and consistent alternative ways of trying to understand the world: religion, the postulates underlying geometry, belief systems underlying ethics, and certain aspects of economics and politics. People working in these areas don’t believe that experiments can: prove whether God exists, determine “ethical” behavior, rule out non-Euclidean geometry, determine optimum economic policy, or prove that DLR doesn’t violate the 2LoT.

• Frank,

All experiments are dependent of theory. Combining theory and an experimental setup we can test, whether the whole is in agreement with the observations, but we cannot test anything special unless we accept a lot of theory. To use pyrgeometers we need the theory of pyrgeometers, the same is true for any other empirical setup that observes radiation. The theory required in the interpretation of such experiments is sufficient for predicting the outcome of the experiment.

Saying in another way. If the result is contrary to standard physics, and assuming that we really trust the empirical part, we can conclude that something in our understanding failed, but we cannot tell what, because it all hangs together. It may equally well be understanding of the devices than understanding the object of the experiment.

We can create all kind of setups of hot and cold bodies. Standard physics can be used to predict the outcomes assuming that the setups are well known and not too complex. Again we can test that the theory as whole leads to right predictions, but the experiment is about a single issue only, if we trust all the rest of the theory, but doubt only a single issue. I don’t think that that’s a logical assumption in any relevant case.

Too many things are dependent on the theory that involves the second law and of other theories of radiation to allow for separating a specific question as decisive for any experiment that is really of interest.

Of course we can look back and think what led to the Second law, i.e. observations like that heat conduction goes from warmer to colder or that a perpetum mobile of the second kind is impossible. None of these was about radiation, but the results do apply also to radiative heat transfer.

• Pekka: If one put a pyrgeometer on dry ice or in liquid nitrogen to reduce the background signal from the radiation emitted by the instrument itself, would this eliminate the complaints about how this devise works?

I rebel at the suggestion that the world is so complex and dependent upon theory that clean, clear-cut demonstrations are impractical. However, my opinion is worthless in the absence of a good proposal. There are other devices for measuring IR, but they all must be kept very cold to minimize the blackbody radiation emitted by the instrument itself.

• Frank,

I don’t want to say or imply that empirical observations are of little value for the science. What I try to explain is that the claims to be proven should be much easier to understand and accept than the value of any new experiments that are supposed to prove them.

All the required evidence and much more is very well known and verified many more times than needed. If that plentiful and very strong existing evidence is not accepted, it would be only illogical to accept the new one.

• on October 28, 2019 at 9:26 pm ThermalIntelligenceAgency

But still, there’s not a single experiment that shows that co2 can warm anything. Just that it can be warmed. Heat absorption is not warming, when heat is absorbed from a hot surface, it cools the surface. The colder something is, the more heat it absorbs.

4. on March 5, 2013 at 8:45 pm | Reply Phil Scadden

SoD – just to make it clear – I am just pointing out for interest. I am not in any way associated with the experiment or the write up. Good to see the author show up.

Pekka – the advantage of the experiment is that for someone who is confused about thermodynamics, they will predict an different outcome from that observed. If you are sure that you understand 2nd law and climate theory has it wrong, then a lab test that fails your intuition is a good reality check. Time to get the text book out again.

5. SoD, and anyone else!

Have changed the posting. I would really appreciate a critique and suggestions for textural improvements or how to improve the experiment.

If any of the science is wrong it is essential to correct it!!

Mike

6. on March 7, 2013 at 10:00 pm | Reply Phil Scadden

” nobody really disagrees in a well defined way on the fact that the Second law is about the net flow of heat.”

Nobody with a real science background, but the argument is more common than think. Over at SkepticalScience.com, the 2nd Law thread is I think the longest one there. It is also full of thought-experiments being used to push one case or another. I think a real experiment is welcome.

• Phil,

The words “in a well defined way” are an essential part of my argument.

All kind of ideas can be promoted, when the question is ill defined, but no experiment can answer such questions. My view is that the issue stays alive, because the alternatives are always ill defined and therefore cannot really be answered by anything, be it experiment or anything else.

The only way to resolve the question in a specific case is to make the participants understand, what they are talking about and to define well their ideas. A few of the participants may ultimately reach that point, most never will.

7. on March 8, 2013 at 12:05 am | Reply Phil Scadden

If someone thinks radiative physics violates the Second law, then they should use their understanding of physics to predict the outcome of this experiment. If your prediction doesn’t match the result, then its a huge hint that just maybe your understanding the physics is in doubt. That is what I see as the value of this experiment.

8. Pekka’s perspective is a good one – that proponents of the “imaginary law of thermodynamics” should put forward a falsifiable theory.

Unfortunately, as we have seen in this blog, it won’t happen – because so far on this blog (more than 2 years) not a single proponent of the theory has been able to articulate it in either:

a) one or more equations
b) explaining what happens to the atmospheric energy that “reaches the ground”

The obvious conclusion to reach is that the proponents of said imaginary theory have no idea about physics basics, even those who claim degrees for themselves.

My working hypothesis, therefore, is that people who understand physics have no idea what motivates “physics-lite” people to reconsider their views.

And armed with this hypothesis, we should attempt to make the most out of the experiment of thefordprefect. And experiments of others. Why not?

Having said that, I also comment on my own failed hypotheses.

My first hypothesis: Demonstrating via measurement of flux and spectral intensity that back radiation reaches the ground – and combining this with the first law of thermodynamics – should convince everyone that atmospheric radiation affects the temperature of the surface.

It failed.

My second hypothesis: Demonstrating the increased entropy when the colder atmosphere increases the surface temperature of the warmer surface should convince everyone that the “greenhouse” effect doesn’t violate the second law of thermodynamics.

It failed.

However, Leon Festinger, father of the theory of cognitive dissonance, would be very happy.

• SoD,

My point is not exactly that the skeptics should present their formulas and falsifiable theories. It’s not reasonable to ask that much from everybody. The point is rather that no experiment is going to impress them as they can get around any outcome. After all they have not presented anything falsifiable.

For this reason I consider futile all attempts to convince by experiments (real or thought ones) people who fundamentally don’t want to accept conventional theories.

That does not mean that describing thought experiments and perhaps also some real experiments would more generally be futile as there are certainly many others who wish to learn. Most of these people do not participate actively in the discussion. They may feel too uncertain, but their comments might be valuable for improving the explanations.

In most cases the comments we see tell immediately, whether they are written by someone who’s willing to learn or by someone who is strongly in denial. There’s a third group, as we see often people who write polite comments where they ask for clarification, but who show soon that their only goal is to confuse and mislead others. (These people may know the correct answers but they never accept them in their comments as that would be against their goals.)

• SoD,

first of all, just thank you – this site has given me a real insight into climate science.

secondly, on convincing others. My hypothesis is simple:
It is impossible to convince a climate skeptic to change their mind.

By climate skeptic, I mean specifically someone who is sufficiently motivated to post on internet forums. The internet provides an ecosystem for people with fringe beliefs to reinforce one another; those here are already totally convinced. The motivation of sceptics is, I think, a belief that climate science threatens their core personal values, typically but not exclusively a right wing ideology.

My only attempt to gain insight on what this means is to try and put myself in their shoes. In a scenario where my core beliefs were threatened by science, how would I behave?

Let’s say that consensus political science research showed very strongly that people living under dictatorship were happier and more prosperous than in democracies. Further research shows clearly that arbitrary detention and torture helps these dictatorships prosper. It is therefore proposed that a dictator is appointed in the UK (where I live) and the rule of law is suspended.

Would I accept this research? No. I would highlight the studies which showed chinks in this. I would argue that liberty was threatened. I would challenge the definitions of happiness and prosperity. I would question the very integrity of the researchers and their motivations. *Nothing* would ever convince me this was a good thing. Not historical studies of dictatorships, not current information on trends of happiness, not models of how society would evolve in future. I would, I think, be quite genuinely convinced that the research was flawed and that I knew better. Sounds familiar?

I don’t know what your motivation is in putting so much time into this endeavour, but I’d suggest that your audience should be people who are genuinely interested in the science of climate. It’s valuable purely for that. Skeptics are not interested, other than to search for chinks in the arguments. Any sceptics who change their views as a result are an unlikely bonus.

thank you again and please continue!

• verytallguy,

I started the blog because there are many people trying to understand climate science and global warming. Including me.

Of course, there are people with ideas that will never change and often I spend a lot of time (too much time?) debating with them.

One sensible reason is to help the many undecided readers see the bankruptcy of their ideas.

Another sensible reason is to try to understand what failed hypothesis sits in their mind so I can present better arguments that address confused ideas that they and other unclear people might think.

And a third reason, less sensible, is sheer boneheaded stupidity on my part.

I prefer a different definition of ‘skeptic’ because I believe I am one myself. A skeptic is one who questions ideas and asks for proof, who weighs up theories and thinks for themselves.

Don’t accept the consensus because it is the consensus, ask for evidence.

But using your definition of skeptic, there is a broad church of skeptics. Some don’t understand any science at all. Some understand a little and some understand a lot.

There is a world of difference between someone valiantly claiming that the ‘greenhouse’ effect doesn’t exist because the second law of thermodynamics says it can’t – yet unable to produce an entropy calculation, or even understand why one is required – and someone who questions whether climate models are accurate to the level required of them. Or someone questioning whether the natural climate variability observed in the past outweighs changes caused by increases in ‘greenhouse’ gases.

In the end, every theory is up for discussion because this is a skeptical blog. (I have reined it in a little, by excluding physics basics as a subject for discussion).

Just because 10 or 100 or 1000 climate papers claim the same result doesn’t mean we can’t question them. Of course, that’s different from blindly refusing to accept their results because we don’t like them. Or claiming they are wrong because we haven’t invested the time in studying – and understanding – the standard theories in textbooks and papers.

• Also,

Let’s not pigeon hole all ‘skeptics’ and/or ‘deniers’ into one catagory. I’m a stauch skeptic/denier of the positive feedback case, but I don’t embrace arguments claiming the GHE violates the 2nd Law or there is no GHE, and other nonsensical things like that.

The real scientific debate is (and should be) about the magnitude of the (theoretical) effect.

9. verytallguy – that is an interesting insight. However, I think climate has some important differences. Firstly, it should not involve a value clash. Its the proposed solutions that involve a value clash and so I think that if proposed solutions conflict with your values, then you need better solutions. So far libertarians have been too deep in denial to consider alternatives.
Secondly, reality intrudes, in a way that doesnt happen with your political debate. However, I notice that many farmers screaming about drought are also adamant it isnt climate change but I think that is slowly changing.

10. Second experiment carried out – still need improvement.

This time a isolated plate is heated with constant power.
An external plate at ambient or warmed is adjacent to an IR window facing the heated plate.

Heated plate temperature rises when warm plate is in position.

11. A lnk to the post mentioned

A Cool Object Reduces Energy loss from a Hot Object

http://climateandstuff.blogspot.co.uk/2013/03/a-cool-object-reduces-energy-loss-from.html

12. Generally ill, have trouble recovery, feel itchy, blurry vision? And so do pharmaceutical companies
which will make billions of dollars from diabetics.
You intend to understand how to cure diabetes.

13. SOD and other friends: I ran into a dilemma that I couldn’t resolve. I often hear that the GHE must exist because [B(lamba,T) – I_0] is generally negative and increasing n makes dI more negative:

dI = n*o*[B(lamba,T2) – I_0]*ds = n*o*[B(lamba,T2) – B(lamba,T1)]*ds

Let’s consider a “composite temperature” T1 for all of the locations that contributed to I_0. (The earth’s blackbody equivalent temperature is a similar composite.)

dI = n*o*[B(lamba,T2) – B(lamba,T1)]*ds

Assuming a graybody, the integral of B(lamba,T) over all wavelengths is eoT^4. Setting T2-T1 = -t, and capitalizing the S-B constant (O)

dI = n*o*e*(OT2^4-OT1^4) = n*o*e*O*(-4T^3*t)*ds

(I’ve dropped terms with lower powers of t and replaced T2 with a generic T.) For a constant lapse rate (r) and a mean free path (d), t = r*d. In general, the mean free path is inversely proportional to the density of GHG (n): d = k/n. making t = r*k/n

dI = -4*o*e*O*k*rT^3)*ds

Now dI appears to not depend upon the density of GHGs. If we call the GHE the difference between surface and TOA flux the GHE and we integrate dI from the surface to space, we have a GHE that doesn’t vary with GHGs (n)! (Unless we add so much GHG that the path to space gets much longer – as it is when we compare Earth and Venus).

I recognize that this result is due to saturation and that most of the GHE on our planet occurs at wavelengths where the mean free path is long enough to reduce the probability of escaping to space (or the surface for DLR) by about 50%. I don’t doubt the output from MODTRAN. However, saying that I_0 is greater than B(lamba,T) and therefore that increasing n must reduce dI appears to be an oversimplification. This argument only applies when B(lamba,T2) – I_0 is not inversely proportional to n!

dI = n*o*[B(lamba,T) – I_0]*ds

Comments (especially corrections) would be appreciated.

PS. If I could devise a situation where the lapse rate decreased with n, we would have a situation where the increasing GHGs would increase the flux to space. That could be caused by GHGs that absorb some SWR, like ozone, and perturb the lapse rate. (:))

• Frank,

The original equation, e.g. equation 11 in Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Six – The Equations is:

dI/ds = nσ.(Bλ(T) – Iλ)

1. You have replaced Iλ with I0.

Iλ changes along the path s, which is why it is the subject of the differential equation in the first place.
I should probably have written Is,λ but it starts to get clunky, however, I is a function of the wavelength, λ and the path, s.

I0 [by which it looks like you mean Iλ0, i.e., the monochromatic radiation] – is the intensity at the surface, not the intensity of the radiation when it reaches the layer of the atmosphere we are considering.

All the rest of the problems in your derivation appear to come from this original problem.

You can see in equation 16 of the cited article that we have to solve the equation by integration of equation 11 vs height (or optical thickness) to get Is,λ as a function of I0,λ.

• SOD: Thanks for pointing out a problem in notation. I’ve been mistakenly using I_0 to refer to the radiation entering the path increment ds or dz. If one integrates from z1 to z2 (which I never do personally), it clearly it makes more sense to call I_0 the intensity at z1. Perhaps I can put it more clearly by expressing dependence on altitude explicitly:

dI(z)/dz = n(z)*σ*[B(lamba,T) – I(z)] in general at one wavelength lamba

dI(z2)/dz = n(z)*σ*[B(lamba,T2) – B(lamba,T1)]

where T1 is a composite temperature or blackbody equivalent temperature for the molecules that emitted the average photon traveling upward to reach z2. T1 is the temperature about one mean free path below z2. The greater the density of absorber, the smaller the mean free path and the closer T1 and T2 will be. Things would be simpler if all photons traveled exactly one mean free path.

The rest of the derivation starting with “assuming a graybody” doesn’t change. (Changing to a greybody approximation simplifies the math.)

• Frank,

I didn’t realize it was just a notation issue.

Let’s look at it as a difference equation at a specific location instead of a general differential equation, with temperatures T1 & T2:

ΔIλ/Δz = nλσ.[Bλ(T1) – Bλ(T2)]

Now you are suggesting to integrate over all wavelengths? You have to integrate outside:

∫ {ΔIλ/Δz} . dλ = ∫ {nλσ.[Bλ(T1) – Bλ(T2)]} . dλ

So the problem that I see with what you did originally –

You have integrated only the expression inside the square brackets, which is not possible unless n is a constant. However, it is a function of λ. And also a function of height, although we have fixed this in the revised difference equation.

The whole solution depends on the fact that we can calculate the change in intensity of radiation based on the initial radiation, the number of absorbers as a function of height and the temperature of the gas as a function of height – only when we consider monochromatic radiation (for new readers – “one wavelength at a time”).

Once you try integrating across all wavelengths at each height to get total flux you have lost the key information you need to calculate the absorption at the next height.

• SOD: Thank you for your help. You are right. There was a lot of hand waving going in when I “integrated” over all wavelengths and replaced B(lamba,T) with oT4.

If I (intensity) is integrated over all wavelengths, the result is power flux (W/m2). Does integrating dI(z,λ)/dz over all wavelengths give dW(z)/dz, where W(z) is the power flux at altitude z? If I express the derivative as a limit, is the integral of the limit, the limit of the integral. That question is beyond my mathematical comfort zone.

On the other side, you wrote n(λ) where I am using n(z) – hopefully correctly – for the density of an GHG at altitude z. For purposes of integrating over all wavelengths, n(z) is a constant. o is a function of wavelength, o(λ). I can move the former outside the integral, but not the latter.

dW(z)/dz = n(z)*o*[Int{B(λ,T2)}dλ – Int{B(λ,T1)}dλ] wrong?
dW(z)/dz = n(z)*o*O*[T2^4 – T1^4] wrong?

dW(z)/dz = n(z)*[Int{o(λ)*[B(λ,T2)dλ} – Int{o(λ)*[B(λ,T1)}dλ] right

This is appears to be a dead end. So I’ll pull a rabbit out of my hat and say that the absorption cross-section of my GHG is a constant (o) everywhere within within the range wavelengths integrated and zero outside. Now the equations labeled “wrong?” could be right. So for this artificial GHG, increasing the amount of the GHG won’t change the outward power flux.

An alternative could be do numerical integrations while increase the mixing ratio for the GHG and see if

Int{o(λ)*[B(λ,T) – I(z)}dλ

begin to vary with the inverse of the mixing ratio when the mixing ratio is high enough. It is my hypothesis that it will for part of the path to space, but every atmosphere gets thin at some altitude.

• Frank,

Yes, you are correct, my mistake – n is a function of height,z, and σ is a function of λ.

n(z)
σ(λ)

In answer to the other questions I would have to sit down for a while and be very precise about the units in each term.

Without thinking about it too hard, reviewing the simpler version, the difference version now corrected:

ΔIλ/Δz = nσλ.[Bλ(T1) – Bλ(T2)]

We can see that if we just multiply both sides by Δz we have:

ΔIλ = (nΔz) . σλ.[Bλ(T1) – Bλ(T2)]

(nΔz) = number of absorbers in the path (whereas n = per unit volume)

so the LHS = change in monochromatic radiation and RHS = emitted monochromatic radiation – absorbed monochromatic radiation

which is what we expect.

Once again, if we integrate across all wavelengths for a specific location (or difference of heights) we will get the right answer but it won’t be any use. That is, we can’t integrate it after this with respect to height.

There’s also a tidying up requirement in that Iλ is spectral intensity and not spectral emissive power, so you either have to integrate over all solid angles, or use the plane parallel approximation.

14. What link is about whether molecules in a higher energy state have a higher temperature?

Thanks.