Guest Post by Willis Eschenbach
Short answer? Of course not, that would violate the Second Law of Thermodynamics … BUT it can leave the hot object warmer than it would be if the cold object weren’t there. Let me explain why this is so.
Let me start by introducing the ideas of individual flows and net flows. Suppose I owe you twenty-five dollars. I run into you, but all I have is a hundred dollar bill. You say no problem, you have seventy-five in cash. I give you the hundred, you give me the seventy-five, and the debt is paid.
Now, there are two equally valid ways to describe that transaction. One way looks at both of the individual flows, and the other way just looks at the net flow. Here they are:
Figure 1. Net flows and individual flows. The individual flows are from me to you, $100, and from you to me, $75. The net flow is from me to you, $25.
What does this have to do with cold and warm objects? It points out a very important distinction, that of the difference between individual flows of energy and the net flow of energy, and it relates to the definition of heat.
Looking at Figure 1, instead of exchanging dollars, think of it as two bodies exchanging energy by means of radiation. This is what happens in the world around us all the time. Every solid object gives off its own individual flow of thermal radiation, just as in the upper half of Figure 1. We constantly radiate energy that is then being absorbed by everything around us, and in turn, we constantly absorb energy that is being radiated by the individual objects around us.
“Heat”, on the other hand, is not those individual flows of energy. Heat is the net flow of energy, as represented in the bottom half of Figure 1. Specifically, a heat flux is the net flow of energy that occurs spontaneously as a result of temperature differences.
Now, the Second Law of Thermodynamics is only about net flows. It states that the net flow of thermal energy which we call “heat” goes from hot to cold each and every time without exception. However, the Second Law says nothing about the individual flows of energy, only the net flow. Heat can’t flow from cold to hot, but radiated energy absolutely can.
When an object emits radiation, that radiation goes on until it hits something that absorbs it, whereupon it is converted to thermal energy. The individual temperatures of the emitting and absorbing objects are not significant because these are individual energy flows, and not the net energy flow called “heat”. So there is no violation of the Second Law.
Here’s the thing that keeps it all in balance. If I can see you, you can see me, so there are no one-way energy flows.
Which means that if I am absorbing radiation from you, then you are absorbing radiation from me. If you are warmer than me, then the net flow of energy will always be from you to me. But that says nothing about the individual flows of energy. Those individual flows only have to do with the temperature of the object that is radiating.
So how do we calculate this net energy flow that we call “heat”? Simple. Gains minus losses. Energy is conserved, which means we can add and subtract flows of energy in exactly the same way that we can add and subtract flows of dollars. So to figure out the net flow of energy, it’s the same as in Figure 1. It’s the larger flow minus the smaller flow.
With all of that as prologue, let me return to the question that involves thermal radiation. Can a cold object leave a warm object warmer than it would be without the cold object?
While the answer is generally no, it can do so in the special case when the cold object is hiding an even colder object from view.
For example, if a person walks between you and a small campfire, they hide the fire from you. As soon as the fire is hidden, you can feel the immediate loss of the radiated energy. At that moment, you are no longer absorbing the radiated energy of the fire. Instead, you are absorbing the radiated energy of the person between you and the fire.
And the same thing can happen with a cold object. If there is a block of wood between you and a block of ice, if you remove the wood, you’ll get colder because you will be absorbing less radiation from the ice than you were from the wood. You no longer have the wood to shield you from the ice.
Why is all of this important? Let me offer up another graphic, which shows a simple global energy budget.
Figure 2. Greatly simplified global energy budget, patterned after the Kiehl/Trenberth budget. Unlike the Kiehl/Trenberth budget, this one is balanced, with the same amount of energy entering and leaving the surface and each of the atmospheric layers. Note that the arrows show ENERGY flows and not HEAT flows.
These ideas of individual flows, net flows, and being shielded from radiation are important because people keep repeating over and over that a cold atmosphere cannot warm the earth … and they are right. The temperature and the radiation are related to each other by the Stefan-Boltzmann equation. When we apply the S-B equation to the 321 W/m2 of downwelling “back radiation” shown in the graphic above, it tells us that the effective radiating level is somewhere around freezing, much colder than the surface.
BUT a cold atmosphere can leave the earth warmer than it would be without the atmosphere because it is hiding something even colder from view, the cosmic microwave background radiation that is only a paltry 3 W/m2 …
And as a result, with the cold atmosphere shielding us from the nearly infinite heat sink of outer space, the earth ends up much warmer than it would be without the cold atmosphere.
To summarize …
• Heat cannot flow from cold to hot, but radiated energy sure can.
• A cold atmosphere radiates about 300-plus W/m2 of downwelling radiation measured at the surface. This 300-plus W/m2 of radiated energy leaves the surface warmer than it would be if we were exposed to the 3 W/m2 of outer space.
My best regards to all,
w.
My Usual Request: When you comment, please QUOTE THE EXACT WORDS THAT YOU ARE DISCUSSING, so that we can all understand the nature of your objections.
My Second Request: Please keep it civil. Speculation about the other person’s motives and cranial horsepower are greatly discouraged.
Further Reading: My post entitled “The Steel Greenhouse” looks at how the poorly-named “greenhouse effect” work, based on the principles discussed above.
Math Notes: There’s an excellent online calculator for net energy flow between two radiating bodies here. It also has the general equation used by the calculator, viz:
with the following variables:
and Q-dot (left-hand side of the equation) being the net flow.
Now, when the first object is totally enclosed by the second object, then area A2 is set to a very large number (I used a million) and the view factor F12 is set to 1. This is the condition of the earth completely surrounded by the atmosphere. For the general case, I’ve set area A1 to 1 square metre. Finally, I’ve made the usual simplifying assumption that thermal IR emissivity is 1.0 for the surface and the atmosphere. The emissivity values are greater than 0.9 in both cases, so the error is small. With those usual assumptions, the equation above simplifies as follows, courtesy of Mathematica:
But sigma T ^ 4 is simply the Stefan-Boltzmann radiation for the given temperature. That is why, in the energy budget above, we can simply add and subtract the energy flows to produce the budget and check to see if it is balanced.
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Willis, here are the five heat reservoirs in your picture.
1. sun
2. surface
3. troposphere
4. stratosphere
5. space
The sun is a tiny speck in the sky, the rest is some 186 thousand times larger. However, it is hot (5778 K), while space is cold (several kelvins), so radiative energy coming from the sun is millions of times larger than all the rest due to the fourth power in radiation law. Both heat reservoirs (1 &. 5) can be considered infinite on scales relevant to the climate system.
As for the rest, heat capacity of the surface (including oceans) is vastly larger than any one of your atmospheric layers.
About 30% of incoming solar radiation is rejected by the Earth system, it goes back to space without thermal interaction (albedo effect). That is, only 237 W/m2 gets thermalized in some part of the climate system and from then on it acts like heat (because it is heat), so “back radiation” has no meaning at all, only net heat transfer by radiation, which is an entirely different beast.
Albedo of the Earth system is strictly regulated. We know this, because annual integrated incoming solar radiation is exactly the same for the two hemispheres (due to a peculiar property of Keplerian orbits). Now, absorbed heat is also measured to be the same for the two hemispheres (for decades now, by satellites), in spite of the fact that clear sky albedo of the Southern hemisphere is much lower due to prevalence of oceans there (under clear sky conditions it reflects some 6 W/m2 less back to space than the Northern hemisphere). Not so under all sky conditions, which means there must be more clouds in the Southern hemisphere and by an amount required by an exact match.
This regulation is neither understood nor replicated by computational climate models. Therefore we have no idea what effect increasing level of atmospheric greenhouse gases may have on it, if any. However, temperature obviously depends on albedo in first approximation.
Another interesting notion is that radiative heat transfer from surface to troposphere is next to insignificant, it is 18 W/m2 compared to 98 W/m2 by convection. Therefore heat transfer between the surface and troposphere is hardly affected by greenhouse gases.
As there is no convective heat transfer to and from the other heat reservoirs, the rest of it is purely radiative.
But it is hard to tell, what effect of changing greenhouse gas levels may have on them. For example we do know the stratosphere is cooling lately (TLS: Temperature Lower Stratosphere).
http://images.remss.com/data/msu/graphics/TLS/plots/RSS_TS_channel_TLS_Global_Land_And_Sea_v03_3.png
However, it does not necessarily mean that the 147 W/m2 radiative heat transfer from here to space is decreasing, because outgoing heat radiation of a body depends not only on its temperature, but also on its emissivity. Which, for the stratosphere, is clearly increasing due to increasing greenhouse levels, because it equals to absorptivity under LTE (Local Thermodynamic Equilibrium) according to Kirchhoff’s Law, a defining feature of greenhouse gases.
Willis, here are the five heat reservoirs in your picture.
1. sun
2. surface
3. troposphere
4. stratosphere
5. space
The sun is a tiny speck in the sky, the rest is some 186 thousand times larger. However, it is hot (5778 K), while space is cold (several kelvins), so radiative energy coming from the sun is millions of times larger than all the rest due to the fourth power in radiation law. Both heat reservoirs (1 &. 5) can be considered infinite on scales relevant to the climate system.
As for the rest, heat capacity of the surface (including oceans) is vastly larger than any one of your atmospheric layers.
About 30% of incoming solar radiation is rejected by the Earth system, it goes back to space without thermal interaction (albedo effect). That is, only 237 W/m2 gets thermalized in some part of the climate system and from then on it acts like heat (because it is heat), so “back radiation” has no meaning at all, only net heat transfer by radiation, which is an entirely different beast.
Albedo of the Earth system is strictly regulated. We know this, because annual integrated incoming solar radiation is exactly the same for the two hemispheres (due to a peculiar property of Keplerian orbits). Now, absorbed heat is also measured to be the same for the two hemispheres (for decades now, by satellites), in spite of the fact that clear sky albedo of the Southern hemisphere is much lower due to prevalence of oceans there (under clear sky conditions it reflects some 6 W/m2 less back to space than the Northern hemisphere). Not so under all sky conditions, which means there must be more clouds in the Southern hemisphere and by an amount required by an exact match.
This regulation is neither understood nor replicated by computational climate models. Therefore we have no idea what effect increasing level of atmospheric greenhouse gases may have on it, if any. However, temperature obviously depends on albedo in first approximation.
Another interesting notion is that radiative heat transfer from surface to troposphere is next to insignificant, it is 18 W/m2 compared to 98 W/m2 by convection. Therefore heat transfer between the surface and troposphere is hardly affected by greenhouse gases.
As there is no convective heat transfer to and from the other heat reservoirs, the rest of it is purely radiative.
But it is hard to tell, what effect of changing greenhouse gas levels may have on them. For example we do know the stratosphere is cooling lately (TLS: Temperature Lower Stratosphere).
http://images.remss.com/data/msu/graphics/TLS/plots/RSS_TS_channel_TLS_Global_Land_And_Sea_v03_3.png
However, it does not necessarily mean that the 147 W/m2 radiative heat transfer from here to space is decreasing, because outgoing heat radiation of a body depends not only on its temperature, but also on its emissivity. Which, for the stratosphere, is clearly increasing due to increasing greenhouse levels, because it equals to absorptivity under LTE (Local Thermodynamic Equilibrium) according to Kirchhoff’s Law, a defining feature of greenhouse gases.
“annual integrated incoming solar radiation is exactly the same for the two hemispheres.” I thought that the Southern Hemisphere was getting more (we are closer to the Sun during the Southern summer). Link, please.
Journal of Climate, Volume 26, Issue 2 (January 2013)
The Observed Hemispheric Symmetry in Reflected Shortwave Irradiance
Aiko Voigt, Bjorn Stevens, Jürgen Bader and Thorsten Mauritsen
Kepler’s second law
A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
It means angular speed is inversely proportional to the square of distance to the Sun. On the other hand radiation flux coming from the Sun is also inversely proportional to the same quantity. Therefore incoming radiation integrated for a given angle is constant. The angle between equinoxes is 180 degrees (not counting precession, which is slow anyway and gives a negligible contribution – 25 arc seconds between equinoxes).
Between the spring and fall equinoxes the Northern hemisphere gets as much incoming solar radiation at ToA (Top of Atmosphere) as the Southern one between the fall and spring equinoxes and vice versa.
Q.E.D.
But the point is, annual reflected, consequently absorbed radiation is also the same.
Peter, thank you, you are 100% right. Let’s get to numbers. The Northern hemisphere gets as much solar radiation in 186 days as the Southern hemisphere gets in 178 days. While the total is the same, the Southern hemisphere should be a little warmer – that’s what I meant.
Annual mean temperature of the Southern hemisphere is in fact a bit lower, in spite of it is getting the same amount of energy input on annual bases.
https://data.giss.nasa.gov/gistemp/graphs/
This is why outgoing longwave radiation is not so balanced, the inter hemispheric difference is at least an order of magnitude larger (the Northern hemisphere radiates more to space).
To compensate for it, there is about 256 TW net heat transfer from the Southern hemisphere to the Northern one, mainly by oceanic currents. The difference comes out to be roughly 1 W/m^2.
Is the difference basically due to the absorption of so much more water in the SH?
@A C Osborn November 27, 2017 at 4:22 am
Yes, this is why clear sky albedo of the Southern hemisphere is 1.75% lower than that of the Northern one. Deep water (like oceans) is very dark, except for shallow incidence angles, when water surface acts like a mirror. If the light ray is perpendicular to the surface, only 2% is reflected, while the rest is absorbed at some depth. On the other hand, small water droplets (like ones in clouds) are white.
This is how albedo is regulated to the extent annual average absorbed shortwave radiation be the same for the two hemispheres.
Some say regulation is done by the exact positioning of the ITCZ (Inter Tropical Convergence Zone), which is cloudy indeed.
http://slideplayer.com/slide/7741637/25/images/8/ITCZ+JULY+ITCZ+JANUARY.jpg
However, it can’t be the whole story, because on average the ITCZ lies mostly in the Northern hemisphere, so the Southern one has to have abundant cloud cover elsewhere as well.
Yep. It is average cloudiness between July 2002 and April 2015 as measured by MODIS on NASA’s Aqua satellite.
https://www.nasa.gov/image-feature/cloudy-earth
Thank you.
This diagram appears to show the ITCZ going right through the middle of the Sahara desert in Summer.
I do not think it is accurate
Berenyi
Very illuminating and compelling.
I’ve always felt that normalising adaptation of a complex-chaotic (plus open and dissipative) system such as climate must be taking place.
Your discussion of unity of thermal budgets in both hemispheres is a strong pointer that this is indeed the case.
There is a theoretical proof, that in reproducible closed (but not isolated) non equilibrium thermodynamic systems the MEPP (Maximum Entropy Production Principle) holds.
A system is reproducible iff microstates belonging to the same macrostate can’t evolve into different macrostates, that is, the system is kinda macrostate-preserving.
If the terrestrial climate system were of this kind, Earth would be pitch black as seen from space (it would have low albedo), because most of the entropy production happens, when incoming shortwave radiation gets absorbed and thermalized.
Earth is obviously not black, its albedo is about 30%.
Therefore it can’t be reproducible, that is, it must have at least two microstates belonging to the same macrostate, that can evolve into different macrostates in a short time.
Indeed it is irreproducible, for the climate system is chaotic, because there are turbulent flows in it. True, it is not turbulent below the Kolmogorov length scale, an order-of-magnitude estimate for which is about 1 mm in the atmosphere. However, the atmosphere contains some 5×10^27 cells of this size, with 2.5×10^16 molecules in each (1.5×10^17 degrees of freedom). With that many cells for example average energy per degrees of freedom (temperature) in a cell is expected to fluctuate by one part in ten million. Which, due to the butterfly effect, contradicts reproducibility.
BTW, we would need some 10^22 times more computing power to skip turbulence in computational climate models, which is impossible. So models have to be parametrized in this respect, but, unfortunately, there is no way to validate the parametrization. An Earth sized wind channel would be way too expensive and also, impossible.
The sum of this is that the chaotic nature of the terrestrial climate system not only makes exact calculations impossible, but also determines the color of Earth (light blue, as opposed to black). Also, theory of irreproducible systems (where Jaynes entropy can’t even be defined) is one of the few uncharted territories of classical physics, so we have no idea how albedo is regulated. The only thing we know, it is.
As albedo is a major player in determining surface temperature, the end result is it’s a bit early to construct computational models, because the theoretical foundations are lacking. And building expensive policies on non existent models is beyond insanity.
If only climate scientists would make actual science instead of being mindless advocates in a policy debate, it could turn out better. For example, someone should do experiments on an irreproducible closed thermodynamic system, obviously on one which is a small enough member of this broad class to fit into a lab setup. There are plenty of such systems and we may even learn something important by studying them. Furthermore, it is not a computational exercise for sure.
JOURNAL OF PHYSICS A: MATHEMATICAL AND GENERAL 38 (2005) pp 371–381
doi: 10.1088/0305-4470/38/21/L01
Received 22 December 2004, in final form 13 April 2005
Published 10 May 2005
Maximum entropy production and the fluctuation theorem
R.C.Dewar
Peter, a great explanation, thanks.
There’s a crucial difference between the valid explanation given here in terms of the PRESENCE of a cold atmosphere, whose backradiation reduces RADIATIVE cooling of the surface, and the customary explanation of the so-called GHE, which attributes the ENTIRE increase in surface temperature solely to GHGs.
In fact, an atmosphere without any GHGs would still be warmed by thermal convection and conduction, reducing the cooling rate of the surface by those non-radiative mechanisms. And if water vapor were the sole GHG in the atmosphere, the surface temperature would not be greatly different from what is experienced now.
1sky1
The consensus view is that the reduction in cooling from the presence of GHGs accounts for the entire observed warming above S-B which is usually quantified as 33C.
You are correct that even a radiatively inert atmosphere would have conduction, convection and a surface temperature enhancement with radiation to space going out from the surface alone and the surplus surface KE being cycled up and down indefinitely and switched between KE and PE in convective overturning.
What happens if you then introduce radiative material of any kind, whether water vapour or not, is that some of the energy needed to go out to space comes from within the atmosphere so that less needs to go out from the surface.
In theory that would require a lower surface temperature but instead the lapse rate slope becomes less steep, the vigour of convection falls and energy is taken up by convection from the surface less fast so that the surface stays at the same temperature.
That is how one should integrate the thermal effects of radiative and non radiative processes.
Stephen Wilde
November 25, 2017 at 2:02 pm: Thankyou, Stephen.
Everything over 0K seems to radiate kinetically. If that has no effect, then what does that mean if anything for the spectra measured and touted by warmista?
There were only very shallow convection in an atmosphere completely transparent in IR, only to make latitudinal heat transfer possible. Otherwise temperature would be uniform above a pretty low altitude.
However, between Earth’s surface and troposphere only 15% of heat transfer happens radiatively, but there is a vigorous convection driven by radiative cooling at the top of troposphere. If radiative transfer decreased inside it, heat flux would still remain constant, because convective transfer would increase driven by a greater temperature difference.
Therefore greenhouse gases only have an effect in the upper troposphere and lower stratosphere, where convection is thwarted.
In an atmosphere completely transparent to IR all radiation to space would have to be from the surface and the vigour of convection would have to be at its fastest possible in order to get KE back to the surface in time to equalise radiation out to space with radiation in to space.
You would still have a temperature gradient along the pressure gradient due to the conversion of KE (sensible heat) to PE (non sensible heat) in uplift and the opposite in descent. Due to uneven surface heating and consequent density differentials in the horizontal plane an isothermal atmosphere would be impossible.
If you then add GHGs which provide an additional route for radiation to space from within the atmosphere then those GHGs also distort the adiabatic lapse rate slope to the warm side which reduces the vigour of convection which would otherwise be needed for convection to match surface radiation to space with radiation in from space. The GHGs are then assisting the shedding of radiation to space so that convection doesn’t work so fast.
Due to less vigorous convection the GHGs radiate to space more effectively from a lower warmer height along the lapse rate slope than would otherwise have been the case.
The net outcome is to neutralise any potential for surface warming from those GHGs.
That is why all planets with atmospheres can keep their atmospheres in hydrostatic equilibrium indefinitely regardless of the proportion of GHGs present.
Convection always adjusts to neutralise internal radiative imbalances.
The AGW radiative theory is fatally flawed.
@Stephen Wilde November 28, 2017 at 11:26 am
Why would the atmosphere get colder upwards, if only the surface is cooling?
If it is not getting colder, no convection is possible.
In fact it should be getting colder at least at the adiabatic lapse rate, otherwise a parcel rising would get colder (and denser) than its environment, so the atmosphere would be stable against convection.
FYI: I’m on a physics forum trying to get some answers. Seems Postma is banned from commenting on WUWT, but is aware of this thread. Too bad, he should be able to contribute his view of things.
I used to think all this banning on all sides of the debates was a bad thing but about 10% of the regular contributors on here are repeatedly rude / insulting in comments so I am now thinking we could have a better debate if at least 100 more were banned.
TRB,
I agree wth you. In fact, I would like to suggest to Mr Watts that the best way forward with this particular topic – with is absolutely fundamental to the ‘CO2 = CAGW’ debate – would be to have a closed debate where, for example, a selection of around 8 people only are allowed to post whilst everyone else merely views. To be fair, I would try to arrange the posters to be equally representing the Warmist, Luke-Warmist, Sceptical and Denier groups. All chosen debaters would have to agree to debate without resorting to personal attacks, ridicule, sarcasm etc.
I for one would just love to see an intellectual debate between polite, knowledgeable and respectful protagonists with maybe one other person (ideally unbiased) as referee. Finalising the chosen debaters would be challenging but worthwhile, in my opinion.
As a starting premise or proposition, I would suggest: “There is no valid physical mechanism by which a change in atmospheric Carbon Dioxide can measurably affect the Earth’s average temperature.”
J. Richard Wakefield, Mr. Postma does not “contribute” to discussions, he pollutes them. That’s why he’s unwelcome.
Anthony is very broad-minded about commenting at WUWT, and he welcomes commenters with a wide variety of viewpoints. (It’s a nice contrast to the heavy-handed censorship prevalent at most alarmist climate blogs.) But even Anthony’s great patience has its limit.
I strongly recommend that you stay away from Principia-Scientific (PSI). It is a disinformation site, run by nutjobs.
They mix truth and fiction, which just makes their web site even more dangerously deceptive than those hideous hoax/parody sites, because it makes the fiction harder to recognize.
“Falsehood is never so false as when it is very nearly true.”
– G.K. Chesterton
Much of the material on the PSI site is good articles which they have simply copied from other sources. But the material which they wrote themselves is mostly deceptive, or nuts, or both.
The four main authors at PSI are John O’Sullivan (CEO) [not to be confused with “the good John O’Sullivan,” who writes for National Review, and who the PSI John O’Sullivan occasionally impersonates], Joe Olson, Joe Postma, and Pierre Latour. In addition to the web site, they also have a book, entitled “Slaying the Sky Dragon.” So they are often referred to as “Sky Dragon Slayers,” or just “Slayers.”
Joe Olson and John O’Sullivan are the two most prolific author at Principia-Scientific, and Postma is #3. A google site search for Olson name finds 723 hits (down from 1760 in July). John O’Sullivan has 986 (down from 1030 in July), Joseph Postma has 236 (down from 453 in July), and Pierre Latour has 193 (down from 288 in July):
https://www.google.com/search?q=%28joe+OR+joseph%29+olson+site%3Aprincipia-scientific.org
They used to have a 5th prolific author, Douglas Cotton, but he had a falling out with the others:
https://www.google.com/search?q=%28doug+OR+douglas%29+cotton+site%3Aprincipia-scientific.org
When I say those guys are nuts, I don’t mean they are just a little bit odd. I mean they are stark, raving, clinically insane. For example, this is a quote from a April 17, 2015 email from Joe Olson:
> “9/11 Conspircy Solved, Names, Connections, Details” and my interview
> with Dr James Fetzer, “Unequivocal 9/11 Nukes” are both on youtube.
Yes, you read that correctly. Joe Olson, one of the top two authors at Principia-Scientific, claims to know that the 9-11-2001 attacks were an “inside job” by the Bush Administration, and that the Twin Towers at the World Trade Center were destroyed with nuclear weapons. (If you care to do so you can search for those titles and find his youtube videos; if you are a masochist you can watch them, but I would not advise it.)
For the sake of your sanity, I strongly recommend that you stay away from Principia-Scientific, their web site, and their idiotic “Sky Dragon” book — and that includes Postma.
daveburton: [“When I say those guys are nuts, I don’t mean they are just a little bit odd. I mean they are stark, raving, clinically insane.”]
I consider your post to be utterly distasteful and not worthy of this blog or this debate. I am sure J Richard Wakefield is capable of rising above your personal opinion in making his own mind up.
Moderators – what were you thinking?
[distasteful, yes, but when somebody claims 9/11 was an inside job caused by nuclear weapons, it tends to support Mr. Burton’s opinion that their views on climate aren’t to be trusted.
Mr. Postma seems to be an equal-opportunity hater. read this https://climateofsophistry.com/2017/09/13/the-walking-braindead-flat-earther-science-denier-list/ -mod]
Right Dave,
Postma believes in the stark raving mad position that heat only transfers from warm objects to cold objects per the Second Law and radiative heat flow equation.
Quite a radical belief system.
Postma has at least 7 peer-reviewed publications in legitimate science journals as well. And Dave has how many scientific publications?
Many years ago I declined an invitation to join PSI because I found a certain lack of rationality.
The mass induced surface warming effect based on atmospheric mass and the gas laws via conduction and convection seemed too simple for them since it made them look as misguided as the AGW alarmists.
Given his foul-mouthed abusive posts to anyone who disagrees with he should definitely not be allowed to post his trash on here!
Willis:
Blackbody Radiation in Optically Thick Gases?
Pierre-Marie Robitaille
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.58
http://hockeyschtick.blogspot.co.nz/2014/05/new-paper-questions-basic-physics.html
EXCELLENT! Both highly relevant – well worth reading.
This reminds me of the joke
https://en.wikipedia.org/wiki/Will_Rogers_phenomenon
1. Radiative flux is not a conserved quantity. You cannot add algebraically the radiative flux intensities from two different sources and use the arithmetic result to derive the sink temperature via S-B.
2. Radiation from objects is electro-magnetic with a range of frequencies (with an upper limit) and NOT a stream of little ping pong ball like elementary particles (just stop it with the “photons”, you are confusing yourselves!).
3. If your mind is still boggling and you fancy a diversion down a different less traveled path but with the same destination try this;http://www2.ups.edu/physics/faculty/evans/Pictet%27s%20experiment.pdf
4. The ERL (Effective Radiating Level) is NOT a real physical location (level/layer) from which radiation zaps off to outer space. If you have even the slightest idea that it is please go and research the origin of the term.
Definitions:
Heat – is simply the transfer of energy from a hot object to a colder object. (hence a cold object by definition cannot transfer heat to a hotter object)
Temperature – (hot & cold) a measure of the average kinetic energy of the particles in an object.
Second Law – is about the quality of energy. It states that as energy is transferred or transformed, more and more of it is wasted. The Second Law also states that there is a natural tendency of any isolated system to degenerate into a more disordered state. In simple terms, entropy always increases.
Entropy – is defined as a state of disorder or decline into disorder.
Seems some here are thinking that hot mean heat. That IR radiation is a form of heat, which it is not when the IR is from a colder object than the warmer object interacting with the IR.
It’s the Watts wot done it! Radiative flux in WATTS/m2, people think its like their heaters, 2kW convector or WATT-eva. (Not Anthony’s fault, and probably not his parents’ either).
Superb post! Thank you.
Willis is a brave man to take this on. Willis is right, but this shows that the argument that global warming is simple physics is simply wrong. So many people do not understand this “simple” physics, so the physics is not so simple.
Figure 1 at the top and WE’s explanation of it are a very good start to explaining the Second Law of Thermodynamics. It explains that the law is about net flows. Flow is an amount of something over time, so the diagram could show the two boxes as radiators/absorbers of money over some time period like a day or year. It could even show coins going back and forth to represent photons; maybe that’s taking the analogy too far. Cash flow works to show how net flow is important. It also shows that there is no problem in a poor person sending money to a rich person; it does make the rich person richer.
However, the example does not explain the Second Law of Thermodynamics. There is nothing in the analogy which says the rich person has to radiate more money to the poor one, with a net cash flow of rich to poor.
The Second Law of Thermodynamics was formulated at first from observations, before they even knew what heat was. The theory of why it is so came later and it is not simple
WE, thanks. Unlike usual, skipped all comments to just say much appreciated post. Goes far to clarifying many here commented misconceptions. Well done, in layman’s English.
l am going back over 50 years in my memory but we had thermo course or courses first then had heat transfer courses and it all seemed simple and logical and followed in steps.
In certain circumstances, a second object can slow the cooling of a warmer object.
Only H2O has the capacity to do this in our atmosphere.
Thought about this all night. The issue is the definition of the word “Warming.” “Warming” does not mean Cooling more Slowly, it means the Hot thing actually gets Hotter.
This is impossible, as, since the Hot thing gets Hotter from the Cool thing, the Cool thing will Get Hotter too, making the Hot thing also Hotter, Perpetual Motion.
This should do it for any sophisticated audience.
Micheal Moon wrote, “Thought about this all night… “Warming” does not mean Cooling more Slowly, it means the Hot thing actually gets Hotter.”
Wrong.
Instead of thinking about it all night, you should have opened the door and checked the temperature outside.
On most nights, in most places, the temperature drops as the night progresses, then rises again during the day. If, thanks to GHGs in the atmosphere, or cloud cover, or anything else that retards cooling, the rate of cooling at night is slowed, then the temperature at dawn is warmer than it otherwise would have been.
So in this context “warming” and “cooling more slowly” are equivalent: they make air temperatures warmer than they otherwise would be.
Michael Moon wrote, “This is impossible, as, since the Hot thing gets Hotter from the Cool thing, the Cool thing will Get Hotter too, making the Hot thing also Hotter, Perpetual Motion.”
Wrong.
Have you never snuggled up with a pretty girl on a chilly night (“for warmth” you told her)?
http://c8.alamy.com/comp/BYAG9P/man-and-woman-snuggling-under-blanket-BYAG9P.jpg
Or… have you never built a campfire, or a fire with charcoal briquettes?
If you separate the burning coals, they soon cool too much to sustain combustion. But if you pile several coals together, near each other, they will keep each other hot enough to continue burning much longer.
.webp
Gonna be a wise ass and point out that the microwave (IR) background radiation at 2.75 W/m2 is somewhat stronger than the ~2 W/m2 from increased CO2.
The burning question here is does earth radiation in the atmospheric window make space warmer than it would otherwise be?
Does cosmic background radiation make the earth warmer than it would otherwise be?
And, if any of you would like to argue that Preventing Cooling, or even Slowing Cooling, is the same as Warming, then you have no place in this discussion…
Cooling more slowly is not the same thing as getting hotter. Are we clear? If not, go back to school…
Cooling more slowly involves the temperature going Down. Getting hotter involves the temperature going Up. Clear then?
One more time, going down more slowly is not the same thing as going up. Congratulate Willis on his idiocy several more times, or ruin this blog…
Michael Moon, repeating the same wrong statement over and over does not make it less erroneous. In the context of the Earth’s climate (and in many other contexts) cooling more slowly is exactly equivalent to heating.
Everything on Earth is constantly gaining energy from some sources and losing it from others. It matters not a whit whether you increase the rate of energy gain or slow the rate of energy loss, if you do either then the thing gets warmer.
What’s more, accusing Willis Eschenbach(!) of “idiocy” is an expeditious way to prove beyond a doubt that you’re as dumb as HotWhoppers’ Miriam O’Brien (a/k/a Slandering Sou from Bundangawoolarangeera), who is the only other person I can think of who is foolish enough to say something like that.
From where comes a photon/EM wave? It comes from moving charge, as in a shock from static electricity. Yes, static electricity and light are virtually the same thing. So, photons, come from charge being forced to change direction, as in moving molecules bumping into each other. If one is moving faster than the other one, the resulting EM/photons cannot necessarily catch up to the faster moving one, hence, no heat transfer from cooler to warmer.
“There are more things between Heaven and Earth Horatio than are dreamed of in your philosophy…”
Just one more! If a cool thing could heat a hotter thing, the hotter thing, being hotter now, would heat the cool thing more, which now would get hotter, and heat the hotter thing a little more, and now we have positive feedback, everything keeps getting hotter, perpetual motion, no need to dig up more coal or oil or Nat-Gas, pretty sweet! Good luck with that…
The precept here is that a cool thing can retard cooling of a hotter thing, not that it can make it hotter.
Why is that so hard for some people to understand?
RW:
Exactly.
“everything keeps getting hotter, perpetual motion”
How about you address the problem that your beliefs on the physics of the GHE lead inevitably to that conclusion.
Perhaps, just perhaps, YOUR Beliefs in the scince are therefore wrong….. and indeed the “problem”.
Just a thought you understand.
They are in denial.
Yet they all claim to have minds open to evidence.
They all see the evidence but can always construct a path to ignore…misrepresent misunderstand or reject the evidence.
That relates directly to the character of all skeptics.
Michael & Toneb, surely you are familiar with the concept of a “convergent series”. This sort of feedback may or may not lead to some infinite runaway result. Can you somehow prove the series diverges? Or are you simply picking one answer more or less at random?
“This sort of feedback may or may not lead to some infinite runaway result. ”
Err – I don’t remember saying anything about a “runaway result”.
Just that the GHE is real.
No, Steven Mosher, it relates to the character of all mankind. Well, most of mankind, anyhow — certainly most climate activists.
It is amazing to me how evidence, even overwhelming evidence, so rarely causes people to waver in their opinions. E.g., when I show climate alarmists good news, like the fact that the 30% increase in atmospheric CO2 over the last 70 years has caused no significant increase in the rate of sea-level rise, they should be glad.
http://www.sealevel.info/120-012_Warnemunde_1916-2016_smoothed.png
Wouldn’t you think that people who claim to be concerned about climate change would be relieved at such excellent news?
Strangely, they rarely are. Usually, good news upsets them. They’re apparently so emotionally wedded to their dystopian nightmare that they’ve come to want it to come to pass. No matter how conclusively it is proven, they reject the best scientific evidence, and cling doggedly to dystopian fantasies. They’d rather be right than safe. They’d rather believe their children are doomed than accept that they were wrong. So when you show them good news, they get mad, and respond with angry insults!
That’s pathological. I wonder if it is connected in some way to the strange popularity of horror movies. Maybe it’s the cats.
Steven Mosher
“That relates directly to the character of all skeptics.”
I’m skeptical of that, I’m an engineer, I have a BSC, I am qualified in electrical engineering, computer maintenance and networks, 25+ years programing experience, I owned a professional web design company and built an office/workshop servicing computer and office equipment for local business before even google existed, I have built schools, collages, homes and businesses in an engineering capacity. I have also worked for about 10 bands as a crew member, involving the production and the setting up of equipment including the programing and servicing of robotic lighting systems in hundreds of venues around the UK and Ireland, I am also qualified in horticulture I hold a hfe cert in numeracy. I have studied astronomy, solar physics and planetary mechanics, I have no criminal record, I am personally very polite, well mannered and have an awesome sense of humor and my mum says I’m good looking. Two years ago I ran into a burning building 3 times in an attempt to save a dogs life.
For the past 3 years I have worked as an electronics engineer for a security company and have been working on a project designing and building a portable security system, it’s kinda top secret…
I’m not sure that I can even begin to do myself any justice in a quick comment, but you would be the last person I would ever ask for a character reference.
Sparks, you neglected to mention that your excrement is odorless.
Sorry, Toneb. I must have misread your comment.
So, Sparks, do you have a significant other in your life?
Asking for a friend . . .
“have been working on a project designing and building a portable security system, it’s kinda top secret…”
DOH !!!!! Not any more it isn’t …
I think we can all agree that the people here commenting, at least those that agree with whatever position we hold on some issue or another, are the bestest of the bestest that humanity has to offer.
But not the ones that we disagree with, nosirree Bob…nope. They are rotten to the core…and probably dress silly, have bad hair, and stinky breath.
I can pert near guarantee it.
MM:
Apologies – In haste
I see you are on the “physics” side of the discussion.
Michael,
No perpetual motion, no more than adding insulation to my house causes that. Keep it simple. Insulation is a cool thing, it slows heat transfer from the warm house to the cold outside. Keeping all else equal (furnace heat output to the house held fixed), the house will warm.
Find the fault with this.
The Sun is the furnace.
The GHGs in the atmosphere are the insulation.
(You’ve got to be *very* specific with these bozos, Nate. And even then it rarely makes any difference…)
Uncle Gus.
Yes it is a shame that those same Insulating GHGs are between the Furnace and the Earth isn’t it?
Half the time the biggest GHG ie Water droplets and water vapour are cooling the Earth, are they not?
Or have you never noticed how much colder it is on a Cloudy day?
Or is it a shame, would we want the same daytime temperatures as the Moon?
AC,
“Or have you never noticed how much colder it is on a Cloudy day?
Beg to differ. It can go either way.
This time of year cloudy days can be warmer—indicative that warm moist air has moved in aloft. Late in the day, and at night, clouds block radiative cooling to space, keeping temps elevated.
Michael Moon November 25, 2017 at 10:00 pm
Just one more! If a cool thing could heat a hotter thing, the hotter thing, being hotter now, would heat the cool thing more, which now would get hotter, and heat the hotter thing a little more, and now we have positive feedback, everything keeps getting hotter, perpetual motion, no need to dig up more coal or oil or Nat-Gas, pretty sweet! Good luck with that…
Not if it’s a convergent series in which case a new steady state is reached.
It actually is convergent. If you do the math, it reduces to a really nice Taylor series expansion of
1/(1-h).
where h is the percentage of upwelling that is returned to the surface.
You can easily show that the energy returned to the surface is
[(1/(1-h)-1] of the incoming. So if h=0 nothing returns and if it is 1, the planet blows up.
Willis,
You are abysmally ignorant. You are not stupid, but you do not belong in the deep end of this pool, seriously. You are doing more harm than good with your profound misunderstanding of radiation and Heat Transfer. I beg you, withdraw from these questions, Mann will mock you and the entire blog..
Stop digging, please.
Michael Moon. Those are strong words, and unprettily abusive. But it is you who has missed the point. After the title Can a cold object warm a hot object?, Willis’ opening words were:
Short answer? Of course not, that would violate the Second Law of Thermodynamics … BUT it can leave the hot object warmer than it would be if the cold object weren’t there.
All of your comments have been misdirected, because they have addressed the first part of the above where you seem to have failed to notice that Willis agrees with you (“Of course not“), whereas virtually the entire article addressed the second part (“it can leave the hot object warmer than it would be if the cold object weren’t there“).
Thank you Willis, for an excellent and easy to understand explanation of a challenging subject. However, I think two conditions should be added to make the explanation more stringent.
Firstly, the question should be “Can a Cold Object Warm a Hot Object by means of radiation only
Without this condition, the answer would be “Yes, of course, just take on some clothes and you will soon notice the effect of warming from insulation”.
The second condition is that you have to take into account the effect of reflection. You describe the interaction as if all the bodies were perfect IR absorbers and perfect IR emitters. I know it is to make the description simple, but here I think you are oversimplifying.
A cold object can warm a hotter object by either shielding the warm object from an even colder object, or by being painted in a more reflective surface.
I think the situation easiest to understand is if both the cold and the warm object is rigged in a way so that they initially have a fixed temperature. Say that object A is 40 Celsius which is 20 Celsius warmer than object B because it is heated from an internal source, for instance a lightbulb.
The distance between A and B is so large that only heat exchange by radiation need to be taken in account.
Can we then do something with object B, so that the temperature in A increases?
Yes, we can for instance paint B in a more reflective paint.
Another way to increase the temperature in A is to place another object with a temperature of 30 C between A and B, but with enough distance from A to avoid any heat exchange other than radiation.
/Jan
Jan: “[A cold object can warm a hotter object by either shielding the warm object from an even colder object…”]
Seriously? When have you ever put hot coffee into a Thermos flask to find the coffee gets warmer with time?
Arfurbryant,
Many people here are giving their own examples, such as you have here, substituting them for the original post. The problem is when these examples remove key factors from the original post, that make all the difference.
Your thermos example: you need to compare the coffees temp over timme in the thermos to what it would be if the coffee was in a regular cup. Answer: it will be warmer in the thermos.
Nate,
Thanks for your input. I agree that examples used should be clear. Words are important in this debate.
Hence, Jan’s statement is just plain wrong. You are obviously aware that insulation does not make the warm object warmer. It does, however, retard the rate of cooling of that warm object. No argument with that.
But to imply that my ‘example’ somehow is not correct or even relevant is also not true.
In this context, you should be saying (as Willis did in the first paragraph of the OP) that a cold object can make an object warmer than it would have been if the cold object was not there. But instead you choose to use the phrase ‘warmer in the thermos’. You mean warmer in comparison with no thermos! To be clear, you should say that it is cooling slower than if there was no thermos. The coffee will NEVER be warmer.
Am I being pedantic? Yes. Am I wrong? No.
Does Willis answer his own question “Can a cold object warm a hot object?” Yes in the short answer but he then subtly changes the goalposts by answering a different question with a BUT in the second part of the answer.
Adding a cold object (insulation in this context) in NO WAY makes the warm object even hotter.
Cooling more slowly is not the same as warming.
CO2 is not an effective insulator and it is not in sufficient quantities to insulate, even if it was effective. Adding CO2 at the rate of just over one ppm per year should not be compared to any form of insulating material such as steel, blankets, overcoats etc.
I hope this clarifies my point.
Regards,
Arfur
Arfurbryant,
I do not think you read my example before you responded so I repeat it here:
“I think the situation easiest to understand is if both the cold and the warm object is rigged in a way so that they initially have a fixed temperature. Say that object A is 40 Celsius which is 20 Celsius warmer than object B because it is heated from an internal source, for instance a lightbulb.
The distance between A and B is so large that only heat exchange by radiation need to be taken in account.
Can we then do something with object B, so that the temperature in A increases?
Yes, we can for instance paint B in a more reflective paint. “
Do you disagree with this?
/Jan
OK, however. in the GHE, there is a continuous heat source, the sun. Again this source of heat is conveniently left out of many examples. In your coffee example that is equivalent to having an immersion heater supplying a steady power to the cup. In that case the coffee WILL BE warmer in the better insulated thermos, as compared to a regular cup.
Hi Jan,
Yes I did read your comment and the part that I objected to mostly was the phrase “A cold object can warm a hotter object by either shielding the warm object from an even colder object…”
As to your further point about object A being made warmer by either the addition of reflective paint on object B or by adding a third object C at intermediate temperature (30C) well, YES, I completely disagree with you!
In your examples, there is NO WAY that object A can be made warmer by either painting object B or by adding object C.
Kind regards,
Arfur
Arfurbryant
Imagine a poor homeless person freezing in the streets a winter night. His body temperature has fallen to 35 C and he is desperate because unless he recover his body temperature he will die. Then he finds some thick good insulating winter clothes.
Should he bother to take them on?
According to you, a colder object, the clothes, can never help him recover his body temperature.
Of course, he will be warmer because the insulation help him lose less heat and more of the energy from his body functions will then stay in his body and warm it up.
This is similar to object A, which will warm up because more of the energy from its inner energy source, the lightbulb, will stay in the box when some of the radiation is reflected back.
/Jan
Hi Jan,
You are wrong.
The homeless person will not recover his body temperature by putting more clothes on. All that would do is make him ‘feel warmer’ by reducing his rate of cooling. Unfortunately for him, as far as his body (core) temperature is concerned, all the extra clothes do is to delay his impending death from hypothermia.
By the way, this is not to say putting the clothes on is a bad idea! It would buy him (or her) more time…
Seriously, just try sleeping outside tonight with a really thick sleeping bag around you. Take your body temperature before you get into the bag and take it again in the morning. Without adding any form of external or internal heat, you will find your body temperature is colder in the morning. If you start to feel cold during the night, simply add another sleeping bag and again take your temperature in the morning. You will still be colder in the morning…
Kind regards,
Arfur
Arfurbryant
Do you really mean this?
Well, you are wrong, and I honestly think you are far off now, but let me try one more:
Imagine, as a thought experiment, that the new warm clothes are perfectly insulating. No heat escapes from his body after he takes them on.
Since he is not dead, his body functions must burn some calories, which create some heat, where do you think that heat will go?
/Jan
Hi Jan,
Yes, i really meant that. People who sleep outside will have a lower body temperature in the morning, irrespective of how much clothing they have. If you doubt me, please speak to either a physicist or a medical professional. Don’t take my word for it.
Now, to your thought experiment…
The trouble with ‘thought experiments’ is that people don’t usually think them through.
The direct answer to your question (where does the heat go?) is this:
If the insulation is truly 100% then there will be no heat loss from inside the insulation but, equally, there will be no heat gain by the body. (Can I assume there is an air gap between the body and the insulation?)
However, the person will die relatively quickly because he/she will be unable to breathe once the air inside the 100% insulation is exhausted (and the O2 is replaced by CO2). In addition, the body functions you refer to will use up stored energy, which is of a finite amount and is irreplaceable without compromising the 100% insulation. Once the stored energy is depleted he/she will die.
Either way, ‘thoughtfully’ covering a homeless person with 100% insulation is not going to do him any favours and his body core temperature will not increase at any point.
Sorry if you disagree but please ask someone else. I see no point in discussing this further but I genuinely wish you all the best in the future.
Kind regards,
Arfur
Goodbye Arfur
I had never though that I would ever meet a person who think that putting on insulating clothes in a cold day will not make you warmer.
Now I have.
All the best
Jan
Jan Kjetil Andersen, after patiently, but fruitlessly, trying to explain a little bit of basic science to arfurbryant, wrote, “I had never though that I would ever meet a person who think that putting on insulating clothes in a cold day will not make you warmer.”
In The Road Less Traveled, psychiatrist Scotty Peck defined mental health as dedication to reality. A mentally healthy person is a person who tries very hard to understand the world clearly. He is willing, even anxious, to revise his internal “map” of reality, when new information conflicts with previously held opinions.
Just like the leftists who blather on about “my truth” and “our realities,” as if reality were a matter of perspective, the slayers are not mentally healthy. Evidence, logic, and and even frequently repeated personal experience — as when they put on a coat every day before going outdoors in the winter — are irrelevant to slayers like arfurbryant, Michael Moon, skepticgonewild, “the bad John O’Sullivan,”† Joe Olson, Joe Postma, Pierre Latour, et al.
The “slayer” nonsense is such pure, refined ignorance that it inspired me to wax poetic, which is rare for me. With apologies to the late, great Ogden Nash, I give you:
† “The bad John O’Sullivan” is the Chief Slayer, i.e., CEO of PSI. He should not be confused with “the good John O’Sullivan,” who writes for National Review, and whose identity the bad John O’Sullivan has been known to borrow, when convenient.
“The bad” John O’Sullivan and his comrades cannot be trusted. Here’s a particular infuriating example of their dishonesty:
In 2015 O’Sullivan & Pierre Latour blatantly lied on the PSI web site, and also in emails, about Dr. S. Fred Singer’s views. The web site article was entitled, “Singer Concurs with Latour: CO2 Doesn’t Cause Global Warming.”
After several people objected, in email O’Sullivan wrote, “Fred Singer has now come over to PSI’s view that CO2 can only cool. I suggest you contact him.”
So I did. I forwarded that to Prof. Singer, who was then 90 years old, and asked him:
Prof. Singer replied succinctly:
That’s what I expected. I forwarded it to O’Sullivan & the other slayers, plus some of the people who had been trying to persuade PSI to remove the dishonest article, including Dr. Singer’s friend, Lord Christopher Monckton. But O’Sullivan still refused to to remove the dishonest article from the PSI web site.
Prof. Singer elaborated in a subsequent email:
Jo Nova weighed in, and appealed to O’Sullivan (and cc’d the other three), to do the right thing:
Joe Postma defended O’Sullivan’s and Latour’s dishonesty. He wrote:
Eventually, after Lord Monckton threatened legal action, PSI finally did edit and tone down the article, making it less flagrantly false. It now says “Singer Converges on ZERO Climate Carbon Forcing.”
Sorry about that. that mess is the result of typing <blockquote> when I intended to type </blockquote> Sigh.
[fixed-mod]
Thank you for the support Dave, your poetic verse is hilarious
/Jan
Thanks Dave. That was quite hilarious.
Please explain how 341 W/m2 of solar insolation at the TOA gets magically multiplied to 494 W/m2 at the earth’s surface when the sun is the ONLY source of energy to heat the earth.
Crickets………..
Arfur,
‘Seriously, just try sleeping outside tonight with a really thick sleeping bag around you. Take your body temperature before you get into the bag and take it again in the morning. Without adding any form of external or internal heat, you will find your body temperature is colder in the morning.’
Nice. Next time my toddler has a dangerously high fever, I will just put him in a sleeping bag and put him outside!
Jan, the poor homeless person (unless he is a lizard) has a self-warming body. As long as he has sugar to burn, he will be able to regain a normal body temperature after putting on the insulating clothes.
If you were to find a statue, made of bronze or stone, and put insulating clothes on it, the statue would not get warmer.
skepticgonewild wrote, “Please explain…”
Such simple stuff is left as an exercise for the reader.
Should have stuck to No … There will ALWAYS BE SOMETHING THERE … And never nothing … Unprovable and who cares … Its called insulation … Rate of cooling is NOT heating
Except for a few details, I agree with this way to represent the Earth radiative behaviour.
Indeed what really radiativeley matters is the net radiative energy transfer(~71W/m2).
It has no physical meaning, and is uninformative, to be 392-321W.
I prefer an alternative explanation. It relies on the spectral properties of the atmosphere.
The atmosphere does not behave like a black-body. Its spectrum, seen from the ground, is not a neat black-body spectrum.
Plotted in the frequency domain, it is partly opaque, with a transparent zone.
The radiation of the ground, if there were no “ghg” gasses, would be lower than it actually is, so that most of the power would fall into the opaque zone. Its energy, and temperature, increases until it radiates enough in the transparent zone to reach an energy equilibrium (not a radiative equilibrium).
If you increase the width of the opaque zone, with more water vapor or more CO2, temperatures will increase.
CO2 bands width increase very little with increased CO2 concentrations. Water vapor varies widely and thus has a far greater influence as we very well know.
On Mars there is more CO2 but less water vapor. In a cold and tenuous atmosphere CO2 absorption rays are fine. The ground is cold and emits in the transparent part of the atmosphere.
Paul Aubrin November 25, 2017 at 11:43 pm says:
Except for a few details, I agree with this way to represent the Earth radiative behaviour [Willis’s energy balance diagram]. Indeed what really radiatively matters is the net radiative energy transfer(~71W/m2). It has no physical meaning, and is uninformative, to be 392-321W.
I am open-mouthed with amazement…
You are suggesting that that, although you like the 71W/m^2 result, and 392W/m^2 upward radiation minus 321W/m^2 downward radiation exactly equals 71W/m^2, nevertheless this correct subtraction of two important measured radiation values ‘has no physical meaning’.
So you did the subtraction. You liked the 71W/m^2 result. And then you said that the result is not physically dependent on the two numbers that have generated the result.
What rubbish! Do you not understand that the reason that the upward actual transfer of energy from surface to atmosphere is 71W/m^2, rather than the 392W/m^2 asserted by the surface (due to its temperature) is because the atmosphere (being warm but not as warm as the surface) is moderating the rate of transfer of energy by an opposite assertion of 321W/m^2? This is straightforward 101 physics.
Not content with this blunder, you go one to make an even odder statement:
The radiation of the ground, if there were no “ghg” gasses, would be lower than it actually is…
On the contrary, if there were no GHG gases, the 169W/m^2 of sunlight that is absorbed at the earth’s surface energy would have to be balanced by outgoing radiation only from the surface of exactly 169W/m^2 directly to space. And last time I checked 169W/m^2 was considerably greater than 71W/m^2.
Where do you get these utterly bizarre notions from?
If the ground was at a lower temperature it would emit less, there is no discussion about this.
The 392 anW/m2) energy flux. The temperature of the ground is mostly defined by the wave number range of the “atmospheric window”. The ground must be warm enough to emit through it what is not evacuated by sensible or latent heat.
The net emission (71W/m2) is required for the energy equilibrium at the surface. The difference 382-321 is casual, 382 depends mostly on the wavelength at which H20 and CO2 molecules absorb.
The concept of shielding from a cold object is incoherent – its a misleading way of putting it. What happens, in the case of the wood and iceblock, is not that the wood shields from the iceblock, as if the iceblock were somehow emitting cold. What happens is that the wood is warmer, and radiates back to me. It also absorbs my own radiation, warms, and radiates back accordingly.
The example is right. A cold object between me and a still colder one will indeed lessen my heat loss. But not because its ‘shielding’ me from cold. Because its radiating more back to me, and also absorbing my heat radiation, warming, and then radiating that back.
The dubious concept here is “back”. Any object above 0K will radiate toward all its visible neighbours.
Yes, quite right – its a seductive misleading way of speaking!
Michel: if iceblock is not emitting cold why do you add ice cubes to your coke? Heat flows from hot to cold. It flows from you to wood and from wood to iceblock. You are cooling according to Newton’s law of cooling. The rate of your cooling depends on the temperature difference, which is smaller between you and wood than between you and iceblock. Therefore in the presence of wood between you and the iceblock you are cooling slower than in the absence of it. No backradiation.
If you sit next to a large block of Ice why do you feel the Cold coming off of it?
Why do you not feel warmer?
I have no problem with “Energy making things warmer or slowing their warming” but there are many things that do not fit the scenario.
Why does a hot object cool faster than a cooler object is a classic example.
Another that I have noticed is that the light from an LED Street Light makes the cars frost over quicker, why doesn’t it slow the cooling?
A C Osborn November 26, 2017 at 7:00 am
Another that I have noticed is that the light from an LED Street Light makes the cars frost over quicker, why doesn’t it slow the cooling?
Because for a street light emitting the same amount of visible light an incandescent light will emit even more IR whereas an LED will emit no IR, one reason why they are less expensive to operate.
Phil, I am sorry that I was not clear enough, the cars with LED shining on them do not cool quicker “Compared” to some other kind of light, they do so compared to “Not having LED light shining on them”.
ie the car directly under the light was over 2C colder compared to a car 15 feet away not directly under the light and it got there quicker.
It seems to be something to do the “frosting over” process at night. Dew or condensing moisture in the Air perhaps?
I hope the neighbors did not me sneaking around with my Electronic Thermometer.
ps I have tested an LED light shining on a very close object (a few millimetres) and it warms the object a little (0.5C)
https://en.m.wikipedia.org/wiki/Frost
So many variables. Two cars made of different metals, slight elevation differences, moisture differencs in the air moving around/between cars, length of time each car had been parked there cooling after being driven last, the directional property of LED lights rather than diffuse…etc.
Not to mention differing amounts of insulation under the hood of each car.
pps this was near midnight, I did not go back in the dead of night to see if the car not under the light got down to the same temp as the one under it.