Sunday 14 February 2021

"The Amazing Case of 'Back Radiation' – Part Three"

I dipped back into Science of Doom again for a giggle and ended up at this fine article, it's the third article in a series which is basically a long list of things which are undisputed. The series builds up to this:

Wavelength Dependence on the Temperature of the Source

Of course, radiation from different temperature sources do have significant differences – in aggregate. What most, or all, believers in the imaginary second law of thermodynamics haven’t appreciated is how similar different temperature Planck curves can be:

Notice the similarity between the 10°C and the -10°C radiation curves. Alert readers who have pieced together these basics will already be able to see why the imaginary second law is not the real second law. If a 0°C surface can absorb radiation from 10°C radiation, it must be able to absorb radiation from -10°C radiation. And yet this would violate the imaginary second law of thermodynamics...

Conclusion

[Downward longwave radiation] is emitted by the atmosphere, reaches the surface and is absorbed by the surface. This absorption of energy changes the surface temperature. The physics behind this are [sic] very basic and have been known for around 100 years. Proving that the surface doesn’t absorb DLR should be a walk in the park for anyone with a small amount of cash. But only if it’s true.


Say what now?

Let's assume the ground is zero degrees C. Case A: air from the south wafts in which is +10 C. We'd expect the ground to warm up a bit (and the air to cool a bit). Case B: air from Siberia wafts in which is -10C. A sane and rational person would expect the ground to cool further (and the air to be a bit less cold), but apparently, the ground will warm up almost as much as if the air were +10C rather than -10C. This would to energy appearing out of nowhere (because the air is also getting less cold) and so is clearly impossible.

And I'm not aware that the Second Law says that objects can't absorb radiation from cooler objects. That is a red herring and neither here nor there - if the warmer object is emitting more than it is absorbing, it is cooling down. What the 'Law' says, among many other things, is that heat goes from warm objects to cold objects. Whether that is due to conduction or radiation or anything else is a secondary issue. The word "radiation" only appears once in the very lengthy Wiki article (and once again in the footnotes). Rather conveniently for the forces of common sense and reason, it's in the following sentence:

The second law is concerned with the direction of natural processes. It asserts that a natural process runs only in one sense, and is not reversible. For example, when a path for conduction and radiation is made available, heat always flows spontaneously from a hotter to a colder body.

They seem to be trying to convince themselves of something that in their hearts they know is not true.
---------------------------------------
The Alarmists sometimes use the warming effect of clouds, which is noticeable at night, as evidence to support this nonsense.

That is a different effect. The clouds are emitting their own 'colder' radiation (which has no effect), and also reflecting 'warmer' radiation emitted by the surface back to the surface (which does have an effect), at exactly the same 'warm' frequencies (colours don't change when reflected in a mirror) which the surface absorbs, reducing the net energy radiated away by the surface, thus warming it up (or at least, slows down the cooling process).

Even if you go with the Alarmist theory, if clouds reflect 60% of radiation at all frequencies, this makes it (say) 5 degrees warmer. CO2 can't re-emit downwards more than half of one-tenth of frequencies of radiation, so pro rata, that means about 0.42 degrees of warming and it can never be more than this, no matter how much CO2 there is.

Furthermore, if we are dabbling in crude radiation calculations, CO2 emits at 14 - 16 microns. Using Wien's Displacement Law, this is the peak radiation emitted by a blackbody which is only about 200K, i.e. about negative 70 degrees C. Which sure as heck can't warm the surface, that's just not happening.

63 comments:

Dinero said...

In case B the Ground would cool down slower because the -10 Deg air would warm up and emit IR towards the Ground and the ground would absorb that.

Mark Wadsworth said...

Din, ?

Dinero said...

The ground would cool down slower with -10 Deg air compared with -20 Deg air. And so at any particular time the ground is warmer due to the presence of air even though the air is cooler than the ground.

Mark Wadsworth said...

Din, yes, the ground cools down more slowly with -10 than with -20, ultimately it will drop to -10 rather than to -20. It certainly doesn't get warmer than 0 in either case.

Dinero said...

The warmer the air is the warmer the ground is even though the air is cooler than the ground.

Mark Wadsworth said...

Din, they said "This absorption of energy changes the surface temperature".

They imply that it INCREASES the surface temperature. It only does so if the air is warmer than the ground.

So yes, -10 air "changes the surface temperature"... it makes it colder!

Dinero said...

" They said. " Well , A lot of articles on the net on these subjects are poor.

The point they are trying to make , although maybe badly , is the heat source is the ground and the air is cooler than the ground. And for that scenario the ground is warmer for a warmer air temp even though the air is at a lower temp than the ground.

Mark Wadsworth said...

Din, "A lot of articles on the net on these subjects are poor."

My suspicion is that SoD is ostensibly sincerely Alarmist, but their claims are so obviously full of holes, that maybe it is one of these Big Oil funded greenwash sites that makes Alarmists and hence Alarmism in general look really stupid.

I have spent a whole year genuinely looking for a half-way decent and plausible explanation for Man Made Global Warming and still haven't found a single one that shows CO2 to be the culprit (if there is a reason, it's ozone depletion). It's like searching for that elusive KLN that will knock LVT out of the park, it just doesn't exist.

"the ground is warmer for a warmer air temp even though the air is at a lower temp than the ground."

Well yes, but that is stating the bleeding obvious and not the point they are trying to make. Their claim is that air at -10C will warm ground that is 0 C to warmer than 0 C.

Dinero said...

Their claim is not that air at - 10 Deg will warm the ground to above 0 deg C . The article is outlining DLR downward longwave radiation. As you acknowledge that the ground being warmer for a warmer air temp even though the air is at a lower temp than the ground is ,as you say obvious, then you are pretty much in agreement with the article as that is what DLR describes. ie the -10 Deg air would warm up from the IR from the ground and subsequently emit IR towards the Ground and the ground would absorb that. Thus cooling more slowly.

Mark Wadsworth said...

Din, I completely agree on "cooling more slowly".

Try reading the series, it is a load of Alarmist mumbo jumbo that they don't understand themselves. The point they are trying to make is that back radiation from GHGs WARMS the surface, and doesn't just slow down cooling of the surface.

You don't need to invoke 'radiation' to explain this undisputed effect. If you have surface with a layer of gas over it (GHG or non-GHG), it will cool more slowly than if it's in a vacuum. There's just more stuff there to cool down. But that is f- all evidence for MMGW because it applies to non-GHGs as well.

Dinero said...

You agree on "cooling more slowly". Well you are in agreement with the effect of DLR because that is what it is . If an object cools more slowly then it is, at any particular time , as I said in the first comment, therefore warmer.

Bayard said...

"ie the -10 Deg air would warm up from the IR from the ground and subsequently emit IR towards the Ground and the ground would absorb that. Thus cooling more slowly."

No it wouldn't. If it did, you would have energy travelling from a colder source, the air, to a warmer sink, the ground, which would violate the second law of thermodynamics.

Dinero said...

>Bayard

It Does not violate the second law of thermodynamics because the hotter object is not getting any hotter . It is only cooling down more slowly and is ,therefore at any particular time, warmer than it would otherwise be.

Mark Wadsworth said...

B, we are agreed on "cooling more slowly"

But that applies whether the atmosphere above the surface is GHG or non-GHG so it's a complete non-issue and no "evidence".

They put Argon in double glazing to slow the cooling/radiation, Argon is not a GHG. They make vacuum flasks, not CO2 flasks. Etc.

Dinero said...

It does not apply if the gas is not a GHG . Specifically if a gas that decreases heat loss to space then it is a GH gas.


Vacuum flasks have a silvered surface and So IR is not part of the heat transfer process of the gas in the walls of the flask . They make such flasks with a vacuum rather than C02 because the Co2 would only radiate half the IR towards the inner flask. While the Vacuum would not conduct it at all. The IR is reflected by the silvered surface.

Mark Wadsworth said...

Din, you have ground which is zero degrees C. You waft a load of pure nitrogen or other non-GHG over it at +10 C or -10 C. The ground either cools or warms. Waft some CO2 or other GHG over it which is +10 C or - 10 C, and EXACTLY the same cooling or warming happens.

Don't tell me that CO2 at +10C will warm it faster than +10C nitrogen (once you have adjusted for specific heat capacity and all that stuff).

You now introduce this idea about "heat loss to space" which is a different thing to the interaction between warmer things and colder things i.e. at the boundary layer and the surface.

Dinero said...

No the same thing does not happen, because with the GH gas the IR from the ground is absorbed by the gas, heating the Gas. This gas then emits IR and that adds Ir to the ground and so the ground cools more slowly. And so at any particular time the ground is warmer due to the presence of the GH gas.

Mark Wadsworth said...

Din, you are a bit brainwashed.

Let's start again with frozen ground, you waft pure nitrogen over it which has been pre-cooled to -10 C. Would the nitrogen warm up a bit and cool the ground a bit? Of course it would!

Dinero said...

Yes the ground would cool and the nitrogen would warm. But that is not DLR. And don't jump to talking about folks being brainwashed. I have a BSC and MSC in science topics and have researched this topic, that is to say I am no winging it , ie ,I know what the terms mean. I think the problem is that in physics and so climate discussions cooling down slower and warming are synonymous beacuase all object obove 0 deg kelvin without heat input , are cooling but the distinction should not be used interchangeably.

Mark Wadsworth said...

Din, warming is warming is warming. Atoms and molecules couldn't care less whether the means of heat transfer is conduction or radiation.

"Yes the ground would cool and the nitrogen would warm. But that is not DLR."

The Alarmists just focus on "radiation" because they know it is hideously complicated and you can't apply normal maths. And it sounds scary.

Dinero said...
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Dinero said...

> Mark

The principle is simple.

Take a hot brick (A) put it next to another cold brick (B).

Take another hot brick (C) and put it somewhere in the absence of any another brick.


The Brick (A) remains over the period of the observation warmer than brick (C) because of the presence of brick (B)

Bayard said...

"It Does not violate the second law of thermodynamics because the hotter object is not getting any hotter . It is only cooling down more slowly and is ,therefore at any particular time, warmer than it would otherwise be."

That's not what the second law states. It states that heat cannot travel from a colder source to a warmer sink. You said,

" subsequently emit IR towards the Ground and the ground would absorb that. "

"Emitting IR towards the ground" is the heat in the form of infra-red radiation travelling from a colder source, the air, to a warmer sink, the ground. It matters not what the effect of that heat is, it is the direction of travel in this case that breaks the law.

Dinero said...

> Bayard

There is no "travel" in the second law. It is referring to the temperature of the destinations.

Mark Wadsworth said...

Din, what do bricks radiating at each other from a distance have to do with the transfer of heat by good old fashioned conduction between a gas and a solid which are in direct contact?

How does that prove MMGW even if you gave me the necessary information on dimensions, distances, temperatures, medium in which the bricks are suspended etc to be able to calculate it.

Facts:
1. Conduction is a far quicker and stronger method of heat transfer than radiation. Put you hand NEAR a pan of boiling water and IN a pan of boiling water and you will notice this.
2. Warm argon will warm a solid object in exactly the same way and by the same amount as warm CO2.

B, to be fair, the cooler object is radiating at the warmer one and the warmer one is absorbing it. But as the warmer object is emitting more radiation of its own, it is of necessity cooling down. That is the Alarmist sleight of hand - to imply that this can mean the warmer object warming up further.

Dinero said...

Mark back radiation DLR does not "imply" that an object warms up further rather it is that the temperature that it reaches is warmer than it would otherwise be.

Mark Wadsworth said...

Din, I know it doesn't imply that, where did I say that?

It was SoD who implied that cooler objects can warm warmer objects. That is the whole thrust of their article - slagging off the "imaginary second law of thermodynamics". Read it. What do you think they mean by "believers in the imaginary second law of thermodynamics"?

All this "DLR" is completely irrelevant bollocks anyway.

It is the start temperatures of the atmosphere and surface which matter*. Most of the heat transfer is by conduction/convection. And if some is by radiation, so what? There is only so much (thermal) energy in the atmosphere or the surface, if it radiates a bit then there's less to be transferred by conduction.

* Those are dictated by incoming sunlight and must be in balance. Just about everything else in the atmosphere can be explained without resorting to "DLR" or "ULR" or anything else with "R" in the abbreviation. The only time that you need to take radiation into account is when clouds are reflecting surface radiation back down, and that effect is fairly minor as the night time warming is always slightly less than daytime cooling.

Dinero said...

There is a demonstration of infrared re emission from gas surrounding a warm object and the subsequent absorption by that object on this Royal Society page -
https://royalsocietypublishing.org/doi/10.1098/rsos.192075

Lola said...

MW / Din - my brain hurts.

Is it not a 'fact' that during the day the land (and oceans) warms up because sunbeams and / or heat transfer from warm air? And at night cools down because no sunshine and cooler air? i.e. at night land / oceans radiates heat and conducts heat to the air?

And I have stood on a hard non reflective surface like a road on a hot sunny day and you can feel the heat rising into the air.

And is it not also a 'fact' that the reason we have a nice cozy planet - not too warm not to cold - is because we have a nice insulating atmosphere?

And - I think - what MW is disputing (and I am deeply suspicious of) is that CO2 is adding to that insulation so significantly that sunbeam heat can't escape? leading to us getting hotter ad hotter?

Just askin'.

Mark Wadsworth said...

L, good summary.

Mark Wadsworth said...

Din, that's a proper experiment with a proper write up.

Like all similar experiments, all it shows is that CO2 is a better insulator than normal air.

This is why there was a temperature gradient in the CO2 balloon but not in the normal air balloon. After 20 minutes, the temperature difference was negligible. Remember that the earth's surface is in cooling mode more than half the time!

Like most similar experiments, they compared normal air with CO2 and did not do a control experiment with Argon, which has similar properties to CO2 (specific heat capacity, mass/mole, insulation etc).

Also, they give the temperature of the heating element but not of the gas itself. I assume that the normal air reached the same temperature as the heating element, even though is cannot absorb 'radiation', so as per usual, conduction is the main method of heat transfer.

Bayard said...

"There is no "travel" in the second law. It is referring to the temperature of the destinations."

Oh no?

From Wikipedia: "The first rigorous definition of the second law based on the concept of entropy came from German scientist Rudolph Clausius in the 1850s including his statement that heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time." and I quote:

"subsequently emit IR towards the Ground and the ground would absorb that."

i.e, that the heat, in the form of infra red radiation, is passing from a colder (the air) to a warmer body (the ground).






Dinero said...

>Bayard

In those type of renditions of the 2nd Law The word "heat" is a vague concept .i.e. "Heat" itself cannot flow as it is a measurement , not a substance. Science now knows about conduction convection diffusion and radiation. What it means is that the temperature of a warm object cannot be increased in the specific case when a colder object is introduced to its vicinity that was not there when the first temperature reading was taken.
What it * Does NOT * mean is that IR cannot flow from a cold object to a warm object. Therefore the Presence of C02 can in principle result in the surface reaching a higher temperature or being at a higher average steady temperature.
The mechanism is often called "back radiation" and have a look at its demonstration here on this Royal Society page -
https://royalsocietypublishing.org/doi/10.1098/rsos.192075

Dinero said...

> Mark

Do you concur that an object going through cycles of warming and cooling repeatedly, will be at an average higher temperature due to the presence of CO2.

Bayard said...

Din, your arguments are much more suited to theology than science. "Heat" is not a "vague concept". What is, is "back radiation" and anything else that "disproves" the second law, or do you have a perpetual motion machine to sell me?

Dinero said...

Bayard
No Theology.
You do not like " Vague concept " fair enough . A better phrase is " Ill defined." Heat when the law was worded in the time of steam engines was not as well defined as it is now.
Back radiation does not disprove the second law because the second law does not prevent it.
I am surprised this demonstration was not done years ago. Read it and you will see a demonstration of the mechanism.
https://royalsocietypublishing.org/doi/10.1098/rsos.192075

Bayard said...

Din, it doesn't matter what you call it, what you are positing here is energy moving from an area of lower energy density, therefore higher entropy, the cold air, to an area of higher energy density, therefore lower entropy, the warmer ground. It does not matter the mechanism by which this is done, nor the form which the energy takes, what you are positing in a reduction in entropy without an corresponding and connected increase elsewhere, which is the basis of a perpetual motion machine. This, the second law of thermodynamics says, is impossible.

Dinero said...

Bayard
Care to put that another way. I can not see what you are getting at. The infrared from any object above 0 deg Kelvin directed towards any other, second object that is at any temperature will add to the incident IR upon that second object. Nothing disputable there.

Mark Wadsworth said...

Din: "Do you concur that an object going through cycles of warming and cooling repeatedly, will be at an average higher temperature due to the presence of [any gas with better insulating properties than N2 or O2, such as Ar or CO2]?"

Yes of course I concur. It's common sense and the experiment you linked shows exactly that effect, as I already said.

Dinero said...

> Mark
Argon?
You seem to be missing point.

Do you recognize that an object going through cycles of warming and cooling repeatedly, will be at an average higher temperature due to the mechanism of IR absorption and re-emission of an adjacent cooler gas . ie "Back radiation"

Mark Wadsworth said...

Din, that experiment shows that some gases are better thermal insulators than others. CO2 and Argon have similar thermal insulation properties. That is my point. It is pretty simple and obvious. Some clever scientists re-ran these lab experiments comparing air, CO2 and Argon and got almost exactly the same results for CO2 and Argon.

Anyway, some Alarmist purists say that back radiation is a red herring, it's all about the "effective emitting layer", see today's post.

Dinero said...

"Some clever scientists re-ran these lab experiments" Have you got a reference for that.

" some gases are better thermal insulators than others. CO2 and Argon have similar thermal insulation properties. "

What are you getting at there . Gases are not thermal insulators except for the infrared properties. Conduction and convection makes things colder . It does not not insulate.

Mark Wadsworth said...

Din, some gases conduct less than others. That's why they fill double glazing with Argon. That's a real world example for you. There are tables for thermal conductivity of gases.

I found the write up of the experiment embedded in a comment on a blogsite. It looks pukka but there is no link directly to it.

Dinero said...

So are you thinking the concept of temperature establishment by the inclusion of back radiation is reasonable or not.

Mark Wadsworth said...

Din, gases can slow down transfer of thermal energy and/or of radiation, see today's post. Those are both real things.

The only way to tell which effect you are actually measuring is to do a control with Argon (clearly not a GHG).

Dinero said...

Well could could envision different experiments.

As i asked before are you thinking the concept of temperature establishment by the inclusion of back radiation is reasonable or not.

Mark Wadsworth said...

Din, in practice, radiation and conduction are very similar.

So an object surrounded by gas at 10 degree will end up warmer than one surrounded by gas at -10 degrees, whatever the object's starting temperature is. Whether you explain heat transfer by radiation or by conduction is irrelevant.

But if you want to call it "back radiation" instead of "conduction or radiation", feel free to do so. I just think it's a pointless overcomplication of something that is relatively simple.

Dinero said...

> Mark

You Still have not got it

"So an object surrounded by gas at 10 degree will end up warmer than one surrounded by gas at -10 degrees, whatever the object's starting temperature is. Whether you explain heat transfer by radiation or by conduction is irrelevant."

That is wrong.

An object at -10 that warms its surrounding gas to -20 will not be made warmer By Conduction but it will be made warmer by Infrared radiation. The infrared radiation warming of the source is in the opposite direction to conduction.

Mark Wadsworth said...

Din, my first statement is irrefutably correct.

"An object at -10 that warms its surrounding gas to -20 will not be made warmer By Conduction but it will be made warmer by Infrared radiation. The infrared radiation warming of the source is in the opposite direction to conduction."

??

I will repeat again, everything emits radiation. Cool emits towards warm and warm emits towards cool. I have not disputed that.

The key here is that the net flow is from warmer to colder. The object at -10 will become cooler if it is surrounded by gas that has a starting temp of colder than -10.

Common sense tells us this. If not, you could start with a -10 object and -20 gas and have them constantly warm each other to infinity.

I refer you to my quote from Wiki. Transfer of energy by conduction and radiation go in the same direction.

Dinero said...

Here is a step by step description of the mechanism.

What step do you think you want to question.

1> Object A is heated from a remote source.

2> object A emits IR

3> object B absorbs IR emitted by A

4> object A absorbs IR emitted from B

5> object A Is warmer due to the presence of object B

Moggo said...
This comment has been removed by the author.
Moggo said...

I try to give a simple explanation why Greenhouse gases can heat up the earth.

The sun is hot and emits visible light to the earth. The earth warms up but stays much colder than the sun. So, the earth is only emitting infrared light and not visible light. The earth heats up until it emits the same amount of light that it absorbs. Earth and sun are in balance.

How can this balance be disturbed, so that earth is heating up again?
Either the earth must absorb more, or earth must emit less light.
Has absorption of the earth increased? Has the atmosphere changed in such a way that there are fewer reflection losses? People think not, so they assume that the earth must be emitting less instead. When the earth is emitting less, it is heating up until it emits again the same amount of infrared light and is again in balance with the sun.

So, you can compare two versions of the earth. Both emit the same amount of infrared light but have different temperature. What is the difference between these two earths? Why is one emitting infrared light less efficiently than the other? What is currently the best explanation why the earth is emitting less efficiently? Greenhouse gases prevent the earth from emitting some part of the infrared light into space.

Mark Wadsworth said...

M, I am perfectly familiar with this explanation.

"What is currently the best explanation why the earth is emitting less efficiently?"

Wrong question. The best explanation is ozone depletion in the stratosphere. That leads to cooling in the stratosphere, and the UVB that now gets into the troposphere and hits the surface warms it up. There is a very good negative correlation between temperature and ozone levels, starting in late 1970s.

UVB is several orders of magnitude more powerful than any long wave IR.

Mark Wadsworth said...

B "5> object A Is warmer due to the presence of object B"

A is still cooler than it was when your experiment started. It might cool ever so slightly slower, but the end temperature is the same as if there were no object B.

Bayard said...

Din, I don't want to question any of the steps, but the overall effect is to contradict the second law of thermodynamics.

There are two possibilities:

1) this is an observable, repeatable effect and the second law of thermodynamics is wrong, it is possible to have an energy transfer which results in a decrease in entropy overall. Hurrah, break out the champagne! Nobel prizes beckon. Our energy problems are solved for ever.

2) it is the sort of complete bollocks that results from starting with a theory and selecting data to support it.

“It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.”

― Sir Arthur Conan Doyle, Sherlock Holmes

I'm with Sherlock on this one.

Bayard said...

M, "What is currently the best explanation why the earth is emitting less efficiently?" is very reminiscent of that famous question, "Have you stopped beating your wife?"

Dinero said...

> Mark

" A is still cooler than it was when your experiment started."

No that is not right.
A is warmer at the end of the steps because it is still being heated from the remote source in step 1.

Dinero said...
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Dinero said...
This comment has been removed by the author.
Dinero said...

> Bayard
if you are thinking that warm objects cannot be kept warm by cooler surroundings. Well consider that must be wrong as the Human body temperature is 37 Deg C but the Temperature maintained by central heating is 21 Deg C.

Mark Wadsworth said...

Din: "A is warmer at the end of the steps because it is still being heated from the remote source in step 1."

In that case you are completely and utterly wrong, I'm not replying any more.

Oh and by the way, animals warm themselves from inside. If they die, they cool to whatever the surrounding temperature is. Surely you know that?

Dinero said...

What are you thinking is wrong about it. As the combined fluxes are greater the steady temperature of the object is greater. Thats it.

And animals - the internal heat generation is a heat input.

Mark Wadsworth said...

Din, you claim that you can make a warm object warmer by putting a cold object near it. Just think about that for a second.