Greenhouse Effect: Misunderstanding Entropy Means Misunderstanding the 2nd Law

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Having “cracked the textbook” once again, I’d like you to “get” why entropy is so important.

Consider two billiard balls. We use billiard balls since they give you the right mental model of what is happening. When they hit, very little energy is lost and the most is conserved as Kinetic Energy.

First, let’s consider the fundamental laws of classical physics. There are three conservation laws, laws that say something must always exist unchanged.

One is the conservation of mass. Over time, mass doesn’t disappear. It may change forms and move around, but it isn’t created or destroyed. (Relativity aside, of course, which merely shows that mass and energy are interchangeable.)

Two is the conservation of momentum. No matter what happens in a collision, the net momentum of all the particles is always going to stay the same. Momentum is mass times velocity, which includes direction and speed. A bullet coming out of a gun has a lot of momentum even though it is small. A truck barreling down the freeway also has a lot of momentum because it is massive, even though it is much slower than a bullet.

Einstein’s theory of relativity shows us that light particles are more than just waves, they actually have momentum and can slow or speed things up.

Three is conservation of energy. Energy is the sum total of work done. Work, in the physical sense, is force times distance. Energy is one of those concepts that takes a long time to “get”, but once you understand how energy works, it makes a lot of things much easier to think about.

OK, back to the billiard balls. When two billiard balls hit each other, those three measures are conserved. No matter what happens, the total mass, total momentum, and total energy is conserved.

What about when two billiard balls of the same mass approach each other at the same speed? At the end of the collision, both billiard balls bounce off each other. Each billiard ball leaves the way it came. This is important, for reasons you’ll see in a moment.

Now, let’s talk about temperature. For a long time, temperature was one of those things that puzzled physicists. That’s because the various models they came up with to describe temperature were unsuccessful in describing actual phenomena. Over time, physicists realized that there was some other quantity that was being conserved, although what it was, exactly, they couldn’t exactly say. However, they came up with an equation that looked something like this:

internal energy = temperature x (magical quantity) - pressure * volume

Chemists will quickly realize that an important term is missing. That’s the term that has to do with chemical or phase energy. Don’t worry, we can add it back in later. We’ll just ignore state or chemical changes for now, and pretend that we are working with an ideal gas.

With this equation, all the phenomena that real gasses exhibit are mostly predictable. Things make sense, and you can start finding new conservation laws.

What this describes is that as you put energy in or take energy out, something has to give. Either the pressure or volume changes, or the temperature changes. But the temperature doesn’t change in the same way all the time—it changes in proportion to this magical quantity. But what is interesting is that the magical quantity seems to suck energy and never give it back.

This magical quantity is named “entropy”, which comes from Greek. The “en” part means “internal”, and the “tropy” part means “turning”. This describes how some of the energy you put into your system is “turned” to “internal” energy that is lost forever.

It wasn’t until later that someone was able to build a statistical model of what is actually happening inside the ideal gas that entropy could be described mathematically. Naturally, curious physicists looked at the math and tried to make sense of it. This is where we get the idea of “disorder”. Entropy represents the statistical probability that the particles are doing one thing and not another.

After all, you could imagine that all the gas were on one side of the chamber, leaving a perfect vacuum on the other. All the quantities (mass, momentum, and energy) would be conserved, and so this is a certainly possible state. However, our statistical understanding say that this isn’t likely to happen at all, and so we won’t see that in practice.

That is, you won’t see it after some time has passed. You can certainly start things off with the gas all on one side, but over time, things will get more disordered.

And this is where the 2nd Law of Thermodynamics comes from. It is stated in two forms. One is “Entropy increases or stays the same over time.” No process will reduce total entropy, and at best, you can only keep it constant. The second form, which took some time to realize, is “Heat doesn’t flow from cold to hot (without additional work added.)”

To understand what the second statement means, we need to understand what heat really is. Heat is a kind of energy, but not energy in the normal sense. It’s a magical kind of energy that doesn’t exist at a molecular level. It obeys a whole different set of laws.

Heat is energy transferred (in what form, we can’t say) from something hot to something cold. That is, energy is lost from the hot thing and energy is added to the cold thing. Heat does not flow from a lower temperature to a higher temperature. Heat is not radiation, it is not collisions, it is not air currents or anything else like that.

Now, you can think of heat as being made up of all those microscopic interactions including radiation and convection and conduction and whatever else you can think of. That’s because, at the molecular level, when two systems meet, the particles of each do interact. But if you try to work the other way, from the molecular on up, you are going to miss an important aspect of temperature and heat.

What follows is the entire point of the post.

Let me describe this for you. There is a way to transfer energy into a system and cool it. Strategically radiating something, you can actually cause its temperature to decrease. You can even decrease the entropy of the system. Let me explain what I mean.

You may have heard of Maxwell’s Daemon. Imagine two chambers of gas connected by a tiny hole that only one molecule could pass through at a time. That hole has a door which can be open or closed at any time. A tiny daemon sits at that hole and opens the door or closes it in an instant according to how he likes to.

Let’s suppose that the daemon decides to open the door when a fast particle were approaching from the left, or when a slow particle approached from the right, and keep it shut otherwise.

If the door is open when a fast particle approaches from the left, then the right side increases its total energy by the energy of that particle, and the left side loses the same amount of energy.

If the door is open when a slow particle approaches from the right, then the left side increases its total energy by the energy of the particle, and the right side loses the same.

Over time, net energy would flow from the left to the right. All of the laws of conservation would be satisfied—except the 2nd Law of Thermodynamics. That’s because the right side would increase in temperature, while the left would cool. Heat would be flowing from cold to hot.

Such a situation could be possible if such a daemon could exist. But more importantly, on the microscopic level, we see that not all energy transferred will heat the system it is transferred to. Sometimes, the energy transferred cools the system it is transferred to. Yes, adding energy to a system can cool it!

Well, we can invent other scenarios that behave much like the above. What if the daemon had a set of mirrors. He used these mirrors to direct light from the sun to strike fast particles in such a way as to reduce their momentum. All the conservation laws would be satisfied—except the 2nd Law of Thermodynamics. But the earth would cool as more radiation flowed from the sun.

Of course, Maxwell’s Daemons don’t exist except in our imagination, as far as we know. We don’t even know how such a thing could be built. Such a thing would have God-like powers, the power to create and destroy entire universes.

But Maxwell’s Daemon does show something important. That is that not all photons from the sun increase the temperature of the earth. However, thanks to our understanding of probability and our understanding of that magical quantity entropy, we know that when the earth is cold and the sun is hot, the vast majority of photons do increase the temperature of the earth. But as the earth warms, more and more photons are actually cooling the earth. If the earth were to reach the same temperature as the sun, then the energy flowing from the sun would neither heat nor cool the earth.

This is why heat cannot flow from cold to hot. And this is also why looking at energy alone is a futile exercise. We must use the generalizations that Thermodynamics give us and abandon our microscopic model and understanding when we think about temperature and heat.

42 Responses to “Greenhouse Effect: Misunderstanding Entropy Means Misunderstanding the 2nd Law”

  1. demo kid Says:

    Bravo! You have written a long post here… that contradicts absolutely nothing I’ve said.

    NET heat flow can, in almost every rational situation, never be from “cold to hot”. However, in every single discussion here, we’ve NEVER been talking about the NET heat flow, only an individual component of the system as a whole. Likewise, your statement:

    If the earth were to reach the same temperature as the sun, then the energy flowing from the sun would neither heat nor cool the earth.

    is correct, but it doesn’t imply that the Earth would magically “know” when it’s the same temperature as the Sun. Instead, the energy balance provides a “steady state” where the energy coming in would be balanced by the energy being emitted. Radiation doesn’t magically stop here; it’s just balanced.

    That’s the root of this problem, and why you’ve been consistently wrong with your dispute of the greenhouse effect. Don’t confuse changes in entropy due to ONE component of the system to changes in entropy as a whole.

    • Jonathan Gardner Says:

      NET heat flow

      No such thing as net heat flow exists. Heat is not a real energy expressed in microscopic terms. Heat is an imaginary energy that sums up all of the interactions between two systems.

      Instead, the energy balance provides a “steady state” where the energy coming in would be balanced by the energy being emitted.

      In other words, heat flow would stop. The earth and sun don’t have to be intelligent to know when to stop transferring heat—probability does all the work for us.

      Don’t confuse changes in entropy due to ONE component of the system to changes in entropy as a whole.

      I’m wondering what you mean by this. Is it important to your argument? I can’t tell.

  2. demo kid Says:

    In other words, heat flow would stop. The earth and sun don’t have to be intelligent to know when to stop transferring heat—probability does all the work for us.

    As I’ve mentioned before. But while “heat flow” would stop, the radiation would not. In this case, it would represent a balance of inputs and outputs between the two.

    And again, you consistently ignore the fact that NET energy transfer is not the same as individual inputs and outputs of energy. Radiation as an input and output just doesn’t stop here; it’s just balanced. To understand the total system, you would need to know the inputs from radiation between the cold and warm body, just as you would need to know the inputs from the warm to the cold body.

    • Jonathan Gardner Says:

      As long as you confuse energy, radiation or otherwise, with heat flow, you will be confused.

      If you want to look at the microscopic actions, you have to consider a lot more than what you are considering. It’s never as simple as you think it is. Only Thermodynamics allows us to simplify what is actually happening and talk about things in terms of temperature, pressure, volume and so forth. So if you’re going to talk about these things, you have to talk about it in the language of thermodynamics.

      • demo kid Says:

        As long as you confuse energy, radiation or otherwise, with heat flow, you will be confused.

        This is getting silly. If you have an object in deep space, like the Sun or some wayward astronaut, and that object emits EM radiation because of its temperature, that radiation will reduce the energy found in that object and can increase the temperature of another object.

        Thermodynamics is very specific about the THREE types of heat transfer: conduction, convection, and radiation. When you’re calculating heat in Carnot engines, radiation is negligible… but it doesn’t mean that it fails to exist in the real world.

        In fact, in space — where the Earth and the Sun are located — the only method of heat transfer is radiation. All of those science fiction TV shows and movies where people are flash-frozen if thrown out into space? Complete fiction. Being in space is like being in a Thermos bottle, meaning that you’d only be frozen to the temperature of deep space once you radiated all of your heat away, which takes far more time. Convection and conduction are not the driving forces in energy transfer between the Sun and the Earth, meaning that any discussion of the heat from solar energy has to involve radiation.

        Does radiation just not exist in your world? Do you believe that the Sun transfers its energy to the Earth through convection through the aether? I’m not arguing foreign, alien principles here… I’m discussing principles of heat transfer that are relevant to atmospheric dynamics, and you have yet to show at any point that I’m wrong, or come up with a rational explanation as to why Dr. Spencer’s thought experiment wouldn’t work.

      • Jonathan Gardner Says:

        Does radiation just not exist in your world?

        Radiation exists, along with a whole lot of other methods of heat transfer. They are just irrelevant in the big picture that Thermodynamics is concerned with.

        And you are wrong. Radiation is not the only way that systems transfer heat to space. Space is hardly empty. There is pleny of stuff in space, especially in the vicinity of our sun. Atmospheres can, and do, “boil” into space. even solid substances lose some of their mass to space.

        The point I am trying to make, and the point you keep missing, is that when heat is transferred, the method of transfer is not important. It doesn’t matter whether heat was transferred via radiation or convection or some combination of the two. The calculations remain the same.

        Again, if you think about the microscopic forces involved in heat transfer, you are going to make a lot of wrong assumptions.

  3. tensor Says:

    Radiation exists, along with a whole lot of other methods of heat transfer.

    OK, either “a whole lot” somehow became “two”, or some methods of heat transfer other than “conduction” and “convection” exist. Which is it?

    They are just irrelevant in the big picture that Thermodynamics is concerned with.

    You’re aware that Thermodynamics was defined (by Isaac Asimov, if I recall properly) as “the physics of energy transfer,” right?

    There is pleny of stuff in space, especially in the vicinity of our sun. Atmospheres can, and do, “boil” into space. even solid substances lose some of their mass to space.

    Neither of which is even remotely relevant to the the model of global warming based primarily upon radiative heat transfer.

    The point I am trying to make, and the point you keep missing, is that when heat is transferred, the method of transfer is not important.

    Well, if the heat is adding to global warming, then we need to recognize that radiative heat transfer is the main way energy enters and leaves our biosphere. Now, as you’ve noted, there are other methods. For example, a solar flare recently erupted, showering the earth with a billion tons of charged particles. The Second Law suggests that some of this energy will remain in our biosphere as heat. (Tell me, what’s it like to have your own cited claim contradict your point?)

    It doesn’t matter whether heat was transferred via radiation or convection or some combination of the two. The calculations remain the same.

    If you’re talking strictly about the First Law of Thermodynamics, yes. If you’re talking about the exact methods of heat transfer, no. Conduction of heat is directly proportional to the temperature differential, whilst radiative transfer is proportional to the fourth power of that differential.

    • Jonathan Gardner Says:

      When you discuss thermodynamics, the heat transfer methods really are irrelevant. It doesn’t matter that the heat gets transferred through one method or another, only that the heat transfer occurs. You can measure the insulative effects of different materials and systems, and that helps you determine what the temperature should be for systems at equilibrium. Since adding CO2 to the atmosphere only has a slight cooling effect, then we don’t need to worry about adding CO2 to the atmosphere. It certainly doesn’t create a feedback that would dramatically change the insulation of the atmosphere.

  4. tensor Says:

    Since adding CO2 to the atmosphere only has a slight cooling effect, then we don’t need to worry about adding CO2 to the atmosphere.

    You know what? I’m going to assume, purely for the sake of this discussion, to assume that your groundless claim about carbon dioxide is correct. I’m also not going to correct your omission of NOx gasses. I won’t even talk about all of the heat released from combustion of fossil fuels.

    I can ignore all of that, because your conclusion simply does not follow from your claims:

    It certainly doesn’t create a feedback that would dramatically change the insulation of the atmosphere.

    Assuming all of our carbon emissions have cooled the earth, that means the net influx of radiative energy will dramatically increase, because the rate of radiative heat transfer is proportional to the fourth power of the temperature differential. Therefore, even a small cooling of the earth could cause a rise in the amount of radiant energy received here.

    As the amount of radiant energy received increases, the temperature will rise, because the Second Law says some of that energy will become heat. There’s no reason to assume, as you have here, that the earth will reach a new thermodynamic equilibrium with the sun and space, especially as we keep adding the very factor, carbon dioxide, which caused the disequilibrium in the first place. How would a world with rapid and unpredictable changes in global temperature look from a food-production standpoint, hm?

    The best part of your feckless statement about feedback and systems comes from the very first chaotic system ever described in mathematical detail: the weather. You chose the worst possible example for your groundless claim! (Congratulations, I think.)

    • Jonathan Gardner Says:

      I’m going to assume, purely for the sake of this discussion, to assume that your groundless claim about carbon dioxide is correct.

      Hardly groundless when it is based on actual measurements of the real CO2 gas. See here.

    • Jonathan Gardner Says:

      Therefore, even a small cooling of the earth could cause a rise in the amount of radiant energy received here. As the amount of radiant energy received increases, the temperature will rise

      Let me try to follow you here. Cooling -> X -> Warming. Is that what you just said?

      I’m really trying to understand why you refuse to apply simple thermodynamic principles. You do understand what a derivative is, and why we use that funny squiggly delta (δ) for some quantities and not others?

      If you make a small change in the system, say, decreasing the insulation between two systems by adding CO2, then that would correspond to some change in the heat flow and thus temperatures of the systems. Are you saying that more CO2 means more heat flow from the sun to the earth?

      Again, you’re making the mistake of trying to think about radiation apart from all other heat transfer methods, and that means you’re missing the big picture, which is temperature.

      You can’t fool me by trying to make things more complicated than they are. Stop trying.

  5. tensor Says:

    Again, you’re making the mistake of trying to think about radiation apart from all other heat transfer methods,

    There are only three known methods of heat transfer: conduction, convection, and radiation. (If you know of another, please publish your paper, and become known as one of the greatest physicists of all time.) Heat transfers through a solid (or a contiguous intersection of solids) via conduction; heat is moved via a nonsolid medium via convection, and heat transfers without medium via radiation.

    Now, no solid object connects the earth to space, so conduction is not involved in global warming. Convection usually stops at the top of the earth’s atmosphere; last week, when we received the billion tons of charged particles from the solar flare, was one of the few exceptions. (No convective heat transfer away from the earth has ever been recorded.) That leaves radiation.

    Are you saying that more CO2 means more heat flow from the sun to the earth?

    The rate of net radiative heat transfer from one body to another is proportional to the fourth power of the temperature differential between them. If the earth cools, then the rate of heat transfer from the sun to the earth would increase. If the earth cools, then the rate of heat transfer from the earth to space would decrease. The net result would be an increase in the heat stored in the earth.

    Now, once the earth heated, we might expect these effects to reverse, but, since the rate of heat transfer is very nonlinear (fourth power), we have no assurance it would ever stabilize. We could see a future of rapidly changing global temperatures. How would crop production work in that case?

    We don’t need a meltdown to have global catastrophe. Erratic temperature fluctuations, driven by fossil-fuel emissions, could cause mass deaths as well. That’s why we take this problem seriously.

    You can’t fool me by trying to make things more complicated than they are. Stop trying.

    Yes, we need to stop talking about conduction, convection, and the Second Law. They’re really irrelevant here (except that the Second Law favors warming). Please stick to the basic mechanism of heat transfer to and from the earth: radiation.

    • Jonathan Gardner Says:

      There are only three known methods of heat transfer: conduction, convection, and radiation. (If you know of another, please publish your paper, and become known as one of the greatest physicists of all time.)

      Fourth method: mass transfer! I’m the greatest physicist of all time!

      Bonus question: What fundamental force is used to transfer heat in conduction, convection, and radiation?

      Triple bonus question: Does the earth lose mass to space? If so, how much energy is transferred through this non-radiative atmospheric evaporation?

      Heat transfers through a solid (or a contiguous intersection of solids) via conduction; heat is moved via a nonsolid medium via convection, and heat transfers without medium via radiation.

      OK, I want you to take a deep breath. Examine, carefully, the fundamental equations of Thermodynamics that describes internal energy. Now point to the part of the equation that describes radiation, the part that describes convection, and the part that describes conduction. Ready?

      U = TS - pV + chemical energy

      Now notice how heat transfer is really irrelevant because you can’t find any terms related to particular heat transfer methods. You can do the same for the potential and kinetic energies, noticing how force just disappears from the equation altogether.

      Thinking about radiation when you are describing how heat flows is like thinking about EM forces when you are describing the state of a system after a collision in classical mechanics. We don’t need to know what happened during the heat transfer, just that it did happen.

      Now, if you argued with me that mass was not conserved during a plastic collision because the forces involved, I would screw my face up into a knot and ask, “Wha?” That’s because you don’t consider individual forces that way. All you have to do is catalog each force, notice how mass is conserved for each one, and then solve the general case for any force being applied and derive the energy formulas which no longer rely on individual forces. That’s what you are doing when you are talking about radiation and then talking about temperature. The two don’t relate to each other that way, any more than EM forces relate to kinetic energy.

      The rate of net radiative heat transfer from one body to another is proportional to the fourth power of the temperature differential between them. If the earth cools, then the rate of heat transfer from the sun to the earth would increase. If the earth cools, then the rate of heat transfer from the earth to space would decrease. The net result would be an increase in the heat stored in the earth.

      You missed my point, If a temperature decrease means that the heat transfer increases to the point that the temperature increases, then the temperature didn’t decrease did it? We have a field of math to help us understand how small changes in one variable affect other variables (calculus). You can’t have the same small change both increase and decrease another variable.

      Now, once the earth heated, we might expect these effects to reverse, but, since the rate of heat transfer is very nonlinear (fourth power), we have no assurance it would ever stabilize. We could see a future of rapidly changing global temperatures. How would crop production work in that case?

      One day, a farmer goes outside and it is snowing. Another day, he goes outside and it is hot. Do all farmers put their hands up and give up when they realize that two days of the year can be so different? Of course not.

      Yes, we can’t predict what’s going to happen, and we can barely predict the 5-day forecast. However, that’s ok. We’ve learned to adapt.

      Since you agree with me that climate and weather are fundamentally unpredictable, does that mean you’ve joined the climate skeptics? Or do you still think severely harming our economy is justifiable despite the inherently chaotic nature of weather and climate?

      Yes, we need to stop talking about conduction, convection, and the Second Law.

      I’d like to correct the record here. I was the one saying that conduction, convection, and radiation are irrelevant, and you only need the 2nd Law to see that the Greenhouse Effect is bogus. Our are you now claiming that only the 2nd Law needs to be examined? If so, please explain how heat can reflect or be stored?

  6. tensor Says:

    OK, I want you to take a deep breath. Examine, carefully, the fundamental equations of Thermodynamics that describes internal energy.

    The entire reason global warming exists, and is a problem, is because that equation is more relevant than it used to be. Our atmosphere used to be more transparent to radiant energy than it now is. Humans have added certain gasses to the atmosphere, making the conversion of radiant energy into heat easier. Thus, more sunlight now becomes heat, and more of the energy the earth attempts to radiate away into space remains here. That’s really all there is to global warming, and your pointless flailing does nothing to change that.

    Hardly groundless when it is based on actual measurements of the real CO2 gas. See here.

    Did you even read that page before you supplied the link? Here’s some of what it says:

    Probably as the result of my recent post explaining in simple terms my “skepticism” about global warming being mostly caused by carbon dioxide emissions, I’m getting a lot of e-mail traffic from some nice folks who are trying to convince me that the physics of the so-called Greenhouse Effect are not physically possible.

    More specifically, that adding CO2 to the atmosphere is not physically capable of causing warming.

    These arguments usually involve claims that “back radiation” can not flow from the cooler upper layers of the atmosphere to the warmer lower layers. This back radiation is a critical component of the theoretical explanation for the Greenhouse Effect.

    Sometimes the Second Law of Thermodynamics, or Kirchoff’s Law of Thermal Radiation, are invoked in these arguments against back radiation and the greenhouse effect.

    His response to one “Jonathan Gardner” is priceless:

    Jonathan, I really don’t think you read (or understood) what I wrote. No one is claiming convection isn’t important, and I do discuss its role. Yes, a real (glass) greenhouse shows the importance of convective heat transfer…I even say what the average effect is in degrees of surface temperature for the atmosphere with and without convection.

    If you want to object to something specific I said, then do so. But don’t assume you know what I said based upon your preconceptions.

    Finally,

    Since you agree with me that climate and weather are fundamentally unpredictable, does that mean you’ve joined the climate skeptics?

    I don’t agree, so stop saying I did. Tip: you’ll find science is a lot easier when you start with the facts, and reason your way to the conclusions. Starting with what you want to believe, then throwing misunderstood bits of science and math at it, will fail you every time.

    • Jonathan Gardner Says:

      Let me quote the comment for you, since you missed it even though I supplied a link straight to it:

      However, when one considers the work of Plass and others (about 1955 vintage), and Dr. Elsasser’s section 12, which show CO2 as a (on balance) UPFLUX agent in the Stratosphere, and thus a net COOLING AGENT…I for one, am mystified where the “tropospheric warming” effect of CO2 comes from.

      Does this help you understand? When you ACTUALLY MEASURE the effects of increasing CO2 in the atmosphere, it tends to COOL THE EARTH.

      Regarding my comment, others addressed his reply better than I could.

      Since you agree with me that climate and weather are fundamentally unpredictable, does that mean you’ve joined the climate skeptics?

      I don’t agree, so stop saying I did.

      So you are saying that climate and weather is predictable? How did you manage to solve the differential equations regarding fluid flow? I’m very interested in this, because all of my math and science education point me to the conclusion that those equations cannot be solved.

      Tip: you’ll find science is a lot easier when you start with the facts, and reason your way to the conclusions.

      I agree.

      Fact: Increasing CO2 in the atmosphere tends to cool the earth.

      Fact: A bunch of scientists are claiming such a thing as the Greenhouse Effect exists, when it is undocumented anywhere in any coherent way that doesn’t violate the 2nd Law of Thermodynamics, and actual measurements show increasing CO2 would cool the earth.

      I don’t think you should be arguing from science when your own reasoning is built on such a flimsy basis.

  7. tensor Says:

    Let me quote the comment for you, since you missed it even though I supplied a link straight to it

    I didn’t miss it. I merely read Dr. Spencer’s immediately-following reply, which described exactly how the comment you cited was wrong:

    In Hugh Elsasser’s quote you provided, he only mentions that the atmospheric CO2 layer as SOURCE of IR has no net directional preference, which is true. But his statement is a non sequitor, because he does not address the effect of the layer as an ABSORBER. BOTH are necessary to say anything about temperature.

    Yes, carbon dioxide in the atmosphere can have both a cooling and warming effect. By ignoring the warming effect, one can say it is purely a coolant. But ignoring reality makes one wrong about reality. Can you please understand that now?

    Dr. Spencer also takes care to demolish your entire line of reasoning here:

    The 2nd Law of Thermodynamics: Can Energy “Flow Uphill”?
    In the case of radiation, the answer to that question is, “yes”. While heat conduction by an object always flows from hotter to colder, in the case of thermal radiation a cooler object does not check what the temperature of its surroundings is before sending out infrared energy. It sends it out anyway, no matter whether its surroundings are cooler or hotter.

    Yes, thermal conduction involves energy flow in only one direction. But radiation flow involves energy flow in both directions.

    If you’re trying to convince us that you’re right about science, you might not want to link to a post by a practicing scientist who repeatedly shows how you’re wrong. Just sayin’.

    • Jonathan Gardner Says:

      Dr. Spencer didn’t clarify the matter one bit with his careful wording. Don’t think for a moment that the thermal equations don’t take into account the back-radiation. After all, when you put a warm body against a cool body, the cool body is transferring energy to the warm body. Yet we don’t have to even think about this as we calculate heat flow and temperature and pressure and volume.

      If heat flows, heat flows and you can measure that. If something in the CO2 causes heat to flow more slowly, then we can measure that. Why is it, then, that actual measurements don’t show the Greenhouse Effect? Where is the experimental data to demonstrate the Greenhouse Effect? Certainly, if it is called an “Effect”, then not only the physics behind it but the observed phenomena must be common knowledge? And yet, both are lacking.

  8. tensor Says:

    Dr. Spencer described exactly how conduction fundamentally differs from radiation, and then you revert to describing conduction, and trying to reason by analogy from it:

    After all, when you put a warm body against a cool body, the cool body is transferring energy to the warm body.

    Conduction is the only method of heat transfer which is exclusively from a hotter body to a colder one. Convection can, and radiation does, transfer heat from cold to hot all of the time. While the net heat transfer, over time, will be from hot to cold, only via conduction is this net transfer immediate and exclusive. Since radiation and convection are the main methods of heat transfer in our climate, reasoning from conduction simply does not work.

    Yet we don’t have to even think about this as we calculate heat flow and temperature and pressure and volume.

    Maybe you don’t think about it, but a climate scientist must. The equation for thermodynamic energy of a fluid, which you have elsewhere quoted, does indeed say nothing about the methods via which energy transferred to and from the fluid, or how the fluid stored the energy. Your refusal to consider these questions is why you failed to understand climate, or the changes thereof.

    If heat flows, heat flows and you can measure that. If something in the CO2 causes heat to flow more slowly, then we can measure that.

    More specifically, carbon dioxide gas does trap and store heat which would otherwise have escaped the biosphere, thus causing the global temperature to rise, yes.

    Why is it, then, that actual measurements don’t show the Greenhouse Effect?

    I was going to describe the global phenomena of receding glaciers, melting polar ice caps, and the increased surface temperatures of the oceans driving more (and more powerful) storms, but you can watch “An Inconvenient Truth” yourself, and read the scientific papers upon which Mr. Gore based his presentation. We already know how you will react, since you’ve done it. You regurgitated the baseless smears of a failed administration against an honorable and innocent scientist, and you described the world-wide community of climate scientists as pathetic dupes of a few evil, Svengali-like master criminals masquerading as honest scientists. All your drivel demonstrated was your abject ignorance of how humans practice science.

    • Jonathan Gardner Says:

      Conduction is the only method of heat transfer which is exclusively from a hotter body to a colder one.

      So, to use your arguments, how do the molecules in the colder end of the metal rod know not to bump into the molecules in the hotter end of the metal rod? The same goes for any heat transfer method. Yes, energy flows both ways in all heat transfer methods, but heat, which is not energy in the normal sense, does not flow in both directions.

      And, please note, that’s not what the 2nd Law states. It doesn’t matter what the heat conduction method is, heat does not flow from cold to hot. There is no such thing as “net” heat transfer, and no one ever talks about it except those who don’t understand Thermodynamics. Please, please understand that violating the 2nd Law of Thermodynamics is the #1 mistake that all crackpots and wannabe great physicists make.

      Yet we don’t have to even think about this as we calculate heat flow and temperature and pressure and volume.

      Maybe you don’t think about it, but a climate scientist must.

      My point exactly. This is why climate science regarding AGW is all wrong. They have to consider something that violates the very laws of nature to extrapolate that CO2 is bad and we should all abandon civilization and climb back up the trees.

      More specifically, carbon dioxide gas does trap and store heat

      NOTHING can trap or store heat. That would violate the 2nd Law of Thermodynamics. Stop inventing physical properties that don’t exist. If CO2 were such a substance, we would line our thermos with it and insulate our refrigerators with it. Getting to absolute zero would be tremendously easy if we just put the substance next to a block of CO2. Using this substance, we could invent perpetual motion machines, draw energy out of nothing at all, and solve all the world’s problems. Of course, this is absurd, which is why nothing can “trap or store heat”.

      you can watch “An Inconvenient Truth” yourself, and read the scientific papers upon which Mr. Gore based his presentation.

      I’m glad you brought it up because it shows how pathetic you are at reasoning and logic. Star Wars has better science than that movie. Even AGW advocates have refuted practically all the claims in the movie. Whatever papers he claims to cite he cites wrongly.

      You regurgitated the baseless smears of a failed administration against an honorable and innocent scientist, and you described the world-wide community of climate scientists as pathetic dupes of a few evil, Svengali-like master criminals masquerading as honest scientists. All your drivel demonstrated was your abject ignorance of how humans practice science.

      And you just made another gaping logical fallacy—argumentum ad hominem, attacking the messenger rather than the message. That means you have run out of legitimate arguments, and my point stands: The Greenhouse Effect is not an effect, isn’t observed in nature, and isn’t based on sound physics, most notably violating the Second Law of Thermodynamics.

      Bravo! It was fun debating you, but you must admit defeat now since you have no arguments to base anything on anymore.

      You really, really need to read what skeptics write. At the very least, you wouldn’t make truly pathetic attempts to defend AGW. You could at least engage the skeptic with language that he understands, and perhaps help a few people see the error in their ways. As it is, AGW is built on a mountain of logical fallacies, such as your argumentum ad hominem and the infamous argumentum ad populum “every scientist agrees with the claims of AGW.”

  9. demo kid Says:

    Dr. Spencer didn’t clarify the matter one bit with his careful wording.

    Nor did you. Answer the question: why was his experiment wrong?

    • Jonathan Gardner Says:

      Dr. Spencer’s experiment was wrong because there isn’t a block of metal floating in space next to the earth, and nothing to suggest a tiny amount of CO2 would create such a block. If he wants to demonstrate the Greenhouse Effect, he should use CO2 and radiation and actual temperature measurements to do so.

  10. tensor Says:

    So, to use your arguments, how do the molecules in the colder end of the metal rod know not to bump into the molecules in the hotter end of the metal rod?

    Um, because they’re embedded in opposite ends of the rod, and therefore cannot touch each other?

    The same goes for any heat transfer method.

    No, in convection, the molecules can move, and collide. In radiation, they can transfer heat without touching.

    Yes, energy flows both ways in all heat transfer methods…

    No, in conduction, energy flows only one way, from hot to cold. In convection, heat may flow both ways, and in radiation, heat does flow both ways. So long as the amount of heat flowing from hot to cold is greater than the amount flowing from cold to hot, the flow can occur.

    …heat, which is not energy in the normal sense…

    Please provide a thermodynamic definition of “energy in the normal sense.” We’ve found heat pretty much everywhere we’ve ever looked, and so it would seem to be a pretty normal phenomenon.

    There is no such thing as “net” heat transfer…

    That statement is as intellectually (and morally) good as you borrowing $10 from me, eventually repaying $5, and then declaring you owed me nothing, because “there is no such thing as ‘net’ cash transfer.”

    They have to consider something that violates the very laws of nature to extrapolate that CO2 is bad and we should all abandon civilization and climb back up the trees.

    While your amusing claim about scientists worldwide not understanding how they’ve misunderstood reality was pretty funny, I rather suspect actual scientists would advocate we develop and deploy more efficient sources of energy, because the research and development required would provide jobs for scientists.

    NOTHING can trap or store heat.

    Actually, black holes seem to do this pretty well.

    Stop inventing physical properties that don’t exist.

    While I’d really like to have a Nobel Prize in physics, I’m pretty sure I’m not the originator of the concept of heat capacitance. But please, write to Stockholm and so nominate me. I’m sure the awesome understanding of science you’re showing here would convince them in my favor.

    How do conduction or convection occur? In each, a material must trap some heat, long enough to move it along (conduction) or around (convection).

    Getting to absolute zero would be tremendously easy if we just put the substance next to a block of CO2.

    Only you are claiming CO2 is a superconductor with infinite heat capacity. I merely claimed it had some heat transfer capacity, and this capacity could suffice to warm the earth. You have yet to disprove this.

    Using this substance, we could invent perpetual motion machines…

    A perpetuum mobile would also violate the First Law of Thermodynamics, so no.

    …draw energy out of nothing at all…

    Ditto. (You really don’t understand thermodynamics at all, do you?)

    Even AGW advocates have refuted practically all the claims in the movie. Whatever papers he claims to cite he cites wrongly.

    (Examples of which include SHUT UP THAT’S WHY, and et cetera, and also, too. Did we mention that algore is fat?)

    And you just made another gaping logical fallacy—argumentum ad hominem, attacking the messenger rather than the message.

    I accurately described how you dismissed all evidence and conclusions you didn’t like, by smearing anyone who collected the evidence and formed the conclusions. That behavior is very relevant to evaluating your supposed claims about science. However, it’s good to see you admitting how your own ad hominem attacks upon scientists have discredited you. Bravo, or whatever.

    …most notably violating the Second Law of Thermodynamics.

    You know, The Second Law is not some version of Maxwell’s Silver Hammer, which you can swing to smash all pesky scientists and their inconvenient truths. We should take a moment here and actually examine it.

    It can be stated in several ways. The simplest version relating to entropy is:

    In a system, a process that occurs will tend to increase the total entropy of the universe.

    The earth is a small part of a very big universe, connected thermodynamically to it via radiation. Plenty of seemingly-impossible things can happen here, if the net effect is to increase the entropy of the universe.

    The statement of The Second Law to which you seem to be clinging, with ever-increasing desperation, is the one about heat flow:

    Heat generally cannot flow spontaneously from a material at lower temperature to a material at higher temperature.

    Note the word “spontaneously”: heat can indeed flow from cold to hot, but needs to be driven somehow. The sun can be a pretty big driver, connected thermodynamically to the earth via radiation.

    Anyway, thanks for showing how far global-warming denialists need go to keep their belief system intact. (“NOTHING can trap or store heat” will keep me chuckling for awhile.) Have you all applied for tax-exempt status with the IRS? After all, the strength of your belief in the inexplicable seems pretty strong.

    P.S.:

    Dr. Spencer’s experiment was wrong because there isn’t a block of metal floating in space next to the earth…

    I think these folks might disagree. Then again, they’re scientists; what could they possibly know?

    • Jonathan Gardner Says:

      About the rod… are you saying that there is a gap between every part of the rod, so that no part of the rod is touching another? I don’t understand how you can say that the cold end doesn’t touch the warm end. If you admit that the cold end does touch the warm end, and that the cold end isn’t at absolute zero, then the cold end would vibrate or bump into or otherwise transfer some energy to the warm end. This energy is not heat, but it is kinetic or potential energy.

      On convection, sure you have a situation where mass is transferred, but that’s already accounted for as well in the fundamental laws of thermodynamics. That’s why we classify a group of problems related to heat transfer when no mass is transfer, and another class where mass can freely transfer.

      Ultimately, every heat transfer method boils down to two particles interacting with some force, and that force is usually the electromagnetic force.

      Your analogy of cash to heat is flawed. Heat doesn’t behave that way. It isn’t something that is stored and it only transfers from the hot to the cold.

      On black holes and the Second Law, Dr. Hawking discovered that black holes radiate. See http://en.wikipedia.org/wiki/Black_hole_thermodynamics for an interesting discussion on how the 2nd Law applies even to black holes.

      Heat capacitance is a new term I’ve never heard before. Heat Capacity, however, is something I have heard of, and it describes how quickly heat transfer will change the temperature of the substance, not how much heat is stored. Again, no one talks about storing heat because it is absurd.

      I think you were missing my point about heat and the 2nd Law. If the 2nd Law is violated by heat flowing from cold to hot, or by a substance capable of storing heat, then everything in physics breaks down and nothing applies anymore. This is what I mean when I say it is absurd—it leads to results which make no sense at all. I’ve described some of the absurd results, which you seem to agree are absurd.

      So do you agree then that nothing can store heat and heat is transferred from hot to cold without additional work? In other words, do you agree that the 2nd Law is inviolable?

      If we agree, then we can have a reasonable discussion. If we don’t agree, then I’ll keep showing you how absurd you are for thinking that the 2nd Law can be violated.

      If you agree with the 2nd Law, then tell me, once again, because I keep missing it, how heat flows from the cooler atmosphere to the earth. Which cycle is used to add additional work to transfer heat from the cold atmosphere to the warm ground? If it helps, perhaps you can give me precise names for each step of the process, something that reads like the Carnot Cycle.

      On the moon, I would ask you this: How does changing the amount of CO2 in the atmosphere change the heat properties of the moon? I’m genuinely curious, because the way you make it sound, doubling the amount of CO2 in the atmosphere is like putting a large block of metal in space near the earth. How does the moon relate to this?

  11. tensor Says:

    About the rod… are you saying that there is a gap between every part of the rod, so that no part of the rod is touching another?

    No, I considered it to be a solid bar, at a range of temperatures far below the metal’s melting point. You wrote:

    …how do the molecules in the colder end of the metal rod know not to bump into the molecules in the hotter end of the metal rod?

    The molecules at one end cannot make direct physical contact with the molecules at the other end; this is part of the definition of “solid”. Their only method of heat transfer is via the intermediate molecules. They accept heat energy only from their immediate neighbors. This is part of the definition of conductive heat transfer.

    If you admit that the cold end does touch the warm end…

    The cold end does not touch the warm end. Therefore, heat transfer between them is only via conduction through intermediate molecules.

    …then the cold end would vibrate or bump into or otherwise transfer some energy to the warm end.

    No, the molecules at the cold end would only accept heat from their neighbors. They would not transfer it back until and unless the entire bar was at the same temperature, at which point every molecule in the bar would give and receive heat in equal measure. This is what we mean by the same temperature, and by thermodynamic equilibrium, within a solid.

    This energy is not heat, but it is kinetic or potential energy.

    Please use your terms with care. Kinetic energy on the microscopic scale is heat; on the macroscopic scale it can be work.

    On convection, sure you have a situation where mass is transferred,

    Convection is the physical carriage of heat from one place to another by a fluid. This may or may not involve a net mass transfer.

    It isn’t something that is stored and it only transfers from the hot to the cold.

    Have you never walked by a brick wall at the end of a hot Summer day? The bricks have absorbed solar radiation all day, and are now radiating it to their (now cooler) ambient air. Of course the bricks store heat.

    Yes, spontaneous heat transfer will generally be from hot to cold; that is what The Second Law of Thermodynamics clearly states. You seem to have ignored the two adjectives I just italicized. If we have a sufficiently large convective system, we may see some local, limited transfer from cold to hot, so long as the overall heat transfer in the system is from hot to cold. Put another way, we may see some local and limited reductions in entropy, so long as the entire system in question sees some net increase in entropy.

    But note carefully: the Second Law applies only to a closed system. If the system is constantly receiving (or losing) energy to the outside universe, then the Second Law merely requires the entire universe to undergo an increase in entropy. The local system can see a constant decrease in entropy, so long as the universe records an increase in entropy.

    The earth is not a closed system; it interacts thermodynamically with the entire known universe, via the mechanism of radiation. So long as the entire universe experiences a net reduction in entropy, heat can flow from cold to hot everywhere on the earth. (Of course, we would not expect to see such a large, spontaneous reduction very often, or even at all; but it could happen.)

    On black holes and the Second Law, Dr. Hawking discovered that black holes radiate. See http://en.wikipedia.org/wiki/Black_hole_thermodynamics for an interesting discussion on how the 2nd Law applies even to black holes.

    Yes, I am aware of Dr. Hawking’s idea of black hole dissipation; I find it comforting, to say the least. But I never claimed that the Second Law does not apply to black holes, only that a black hole can absorb a huge amount of heat (and everything else) in the short term.

    Heat Capacity, however, is something I have heard of, and it describes how quickly heat transfer will change the temperature of the substance,

    Correct.

    … not how much heat is stored.

    Wow, what a non sequitor! A substance with a large heat capacity will absorb more heat for a given temperature increase, precisely because it stores more heat!

    Please note that you have two variables there: the heat capacity of the substance (which in a fluid is normally measured at constant volume, Cv, and the heat conductivity of the substance. These values determine how quickly heat will saturate a given amount of substance. For instance, metal has high values of both, meaning it will quickly absorb a large amount of heat; water has a high heat capacity (Cv), but a low conductivity, meaning a large amount of heat will still take a long time to flow to or from liquid water.

    I think you were missing my point about heat and the 2nd Law. If the 2nd Law is violated by heat flowing from cold to hot, or by a substance capable of storing heat, then everything in physics breaks down and nothing applies anymore.

    I agree. Please understand that, under the correct circumstances, heat can flow from cold to hot.

    I’ve described some of the absurd results, which you seem to agree are absurd.

    No, I think your examples are wrong.

    So do you agree then that nothing can store heat…

    Pretty much any material can store heat.

    and heat is transferred from hot to cold without additional work…

    Of course it is. But heat can also be transferred from cold to hot without additional work, and without violating any law of thermodynamics.

    If we don’t agree, then I’ll keep showing you how absurd you are for thinking that the 2nd Law can be violated.

    Never have I claimed The Second Law of Thermodynamics can be violated. I have merely claimed that your interpretation of The Second Law is not correct. You have ignored the conditions clearly stated, and have interpreted them as absolutes.

    If you agree with the 2nd Law, then tell me, once again, because I keep missing it, how heat flows from the cooler atmosphere to the earth.

    I never claimed this.

    Which cycle is used to add additional work to transfer heat from the cold atmosphere to the warm ground?

    Neither the ground nor the air has a uniform temperature, only an average temperature. Where a local temperature difference exists, heat will there spontaneously flow from hot to cold. (Have you never, here in the Pacific Northwest, felt a cold breeze on a warm day?)

    On the moon, I would ask you this: How does changing the amount of CO2 in the atmosphere change the heat properties of the moon?

    You made this statement:

    Dr. Spencer’s experiment was wrong because there isn’t a block of metal floating in space next to the earth…

    Your statement is wrong. There is a large “block” (“sphere”) of metal orbiting the earth. As you can see with your own eyes, it reflects sunlight to the earth, sunlight which would otherwise pass into deep space. The earth also sends reflected light to the moon, which reflects some of it back:

    On certain nights, when the angles are right, and the moon is a slender crescent, its circle shows in a ghostly glow of earthly luminescence…

    Thus, the earth receives more solar energy than it would without the moon, and the earth keeps more energy than it would without the moon. This is Dr. Spencer’s point.

    …doubling the amount of CO2 in the atmosphere is like putting a large block of metal in space near the earth. How does the moon relate to this?

    Because any material near the surface of the earth (maybe even a black hole!) will have this property, even if it is (like the moon) inherently colder than the earth.

    • Jonathan Gardner Says:

      The molecules at one end cannot make direct physical contact with the molecules at the other end; this is part of the definition of “solid”. Their only method of heat transfer is via the intermediate molecules.

      OK, let’s back up and try this again. Do you agree that when heat conduction is occurring, there is a heat gradient across the bar? That is, if you move along the bar from the warm to the cold end, the temperature you measure would get progressively colder?

      Consider any slice of the rod. On one side, the temperature is cooler than on the other side.

      Now, these molecules are vibrating and electrons (since it is a good conductor) are moving about and colliding in one way or another with each other.

      Can you say that the colder side doesn’t transfer some kinetic or potential energy to the warmer side? I’m not talking about heat, I’m talking about microscopic interactions between particles—atoms and electrons.

      If you can say this, then I have shown how conduction exhibits the same properties of radiation. That is, there is some energy transfer from cold to hot, and some energy transfer from hot to cold. I am demonstrating how examining energy transfer alone makes understanding heat transfer more difficult unless you consider everything.

      That is why we don’t think about the heat transfer methods, specifically, when we think about thermodynamics. We only need to consider heat transfer as a whole. We observe that heat doesn’t transfer from cold to hot (unless work is added), and we observe that there is no reflected heat.

      Please use your terms with care. Kinetic energy on the microscopic scale is heat; on the macroscopic scale it can be work.

      I could ask the same of you. I think you are thoroughly confused now, because work is any force applied at a distance, at any scale, microscopically or macroscopically. Individual electrons can work against individual electrons, just like a block of metal can work against another block of metal. The energy transferred may end up as kinetic energy or potential energy or a combination of both.

      Kinetic energy plus potential energy (think of how the particles affect each other with the electromagnetic potentials) are components of the internal energy, which in thermodynamics we need not distinguish.

      A substance with a large heat capacity will absorb more heat for a given temperature increase, precisely because it stores more heat!

      OK, half of your statement is correct, and the other half is incorrect. Again, heat transferred isn’t store as heat. There is no heat potential. It doesn’t work that way. Because of how the internal energy of a system is stored, you can’t store heat as heat. Take the same block of metal that just absorbed a certain amount of heat, and try to extract it again and you will find that it cannot always be done. Some heat goes somewhere, disappearing from the universe forever, because it can no longer be extracted. It isn’t even converted into some other form of energy, it is simply gone. This is why “entropy” got its name—“internal warmth”.

      We can’t build heat capacitors or heat batteries. We can watch energy entering a system as heat change into temperature, entropy, pressure, volume, or chemical energy, or some combination thereof.

      These properties are uncovered if you simply carry out the same experiments that those scientists who discovered these curious properties of heat have done. The laws of thermodynamics are absolute, as far as we can see, and are not to be trifled with.

      But heat can also be transferred from cold to hot without additional work, and without violating any law of thermodynamics.

      Please, please tell me how this is done. Show me, and I will shut up.

      If you have discovered this, you have solved the universe’s energy shortage. See, we can take the warmer substance, move it away from the colder substance, and use it to extract some mechanical or electrical power. When it is cold again, we move it back next to the colder substance and have it warmed again.

      Which cycle is used to add additional work to transfer heat from the cold atmosphere to the warm ground?

      Neither the ground nor the air has a uniform temperature, only an average temperature. Where a local temperature difference exists, heat will there spontaneously flow from hot to cold. (Have you never, here in the Pacific Northwest, felt a cold breeze on a warm day?)

      OK, I think you missed my point. One of the ideas behind the Greenhouse Effect is that the colder air reflects back some heat to the warmer ground, keeping the ground and lower atmosphere warmer than it otherwise would be.

      I asked you how this was done, and you’ve made the absurd statement that cold objects transfer heat to warmer objects. If you can reveal to me the process whereby this is done, I would gladly like to hear it!

      How does changing the amount of CO2 in the atmosphere change the heat properties of the moon?

      You made this statement:

      Let me try once again. I asked, “How does adding CO2 to the atmosphere compare to Dr. Spencer’s experiment of adding a block of metal?”

      You responded with a link that pointed to the moon as having an effect on our climate.

      So I asked, “How does adding CO2 to the atmosphere change the heat properties of the moon?”

      And you said, “You made this statement.”

      I am thoroughly confused. So I ask again, “How does Dr. Spencer’s experiment have anything to do with adding CO2 to the atmosphere?”

      I understand that the moon does have an effect, but I would like to know what the relationship between the moon and CO2 is.

  12. tensor Says:

    Me bad:

    So long as the entire universe experiences a net reduction in entropy, heat can flow from cold to hot everywhere on the earth.

    That should have read “net increase in entropy”. Whoops!

  13. tensor Says:

    … because work is any force applied at a distance, at any scale, microscopically or macroscopically.

    Wrong. Random microscopic vibrations in a solid are heat. The Second Law clearly states that not all of this random motion can be spontaneously recovered as work.

    Can you say that the colder side doesn’t transfer some kinetic or potential energy to the warmer side? I’m not talking about heat, I’m talking about microscopic interactions between particles—atoms and electrons.

    If you can say this, then I have shown how conduction exhibits the same properties of radiation.

    If you’re not talking about heat, then you can’t draw any conclusions about heat transfer methods, such as conduction or radiation. Conduction does not exhibit the same properties as radiation: conduction happens only by direct contact in a physical medium; radiation can travel across vast distances of vacuum.

    Take the same block of metal that just absorbed a certain amount of heat, and try to extract it again and you will find that it cannot always be done. Some heat goes somewhere, disappearing from the universe forever, because it can no longer be extracted.

    That would be a per se violation of the First Law of Thermodynamics, especially as it concerns the Law of the Conservation of Energy. Heat is energy, and energy cannot be created nor destroyed. The Second Law puts restrictions on how much heat can be extracted as work, but heat stored within a body remains unless it can transfer away somehow.

    I understand that the moon does have an effect, but I would like to know what the relationship between the moon and CO2 is.

    The ability of the moon to reflect radiant energy to the earth means the earth receives more solar energy than it would without the moon, and it loses less radiant energy to space than it would without the moon. The addition of carbon dioxide to the atmosphere means the atmosphere retains more heat than it did before this addition, and the earth radiates less heat away to space, because the carbon dioxide gas can reflect the earth’s infrared radiation back to the surface of the earth.

    Finally, I’d like to note that understanding the Second Law isn’t that important to understanding global warming. We really need only the First Law and the knowledge of the properties of the greenhouse gasses. If we want to understand all of the effects of global warming, then thermodynamics is important. For example, the surface temperature of the oceans drives hurricanes, thus effecting a limited and local conversion of heat to organized motion in the atmosphere. So long as the entropy of the entire earth-sun-space system increases, hurricanes can happen. A rise in the surface temperature of the oceans thus drives more (and more violent) storms, an effect we’re seeing now.

    • Jonathan Gardner Says:
      … because work is any force applied at a distance, at any scale, microscopically or macroscopically.

      Wrong. Random microscopic vibrations in a solid are heat. The Second Law clearly states that not all of this random motion can be spontaneously recovered as work.

      Remember you’re trying to claim there is a scientific foundation for the Greenhouse Effect that doesn’t contradict any of the fundamental laws of Physics. Arguing that work is not force applied over a distance is not helping your cause.

      Please re-read the scientific definition of heat. It differs a little bit from what we call heat colloquially. Let me quote from a textbook on the subject, conveniently quoted and cited at Wikipedia:

      In physics and thermodynamics, heat is the process of energy transfer from one body or system to another due to thermal contact, which in turn is defined as an energy transfer to a body in any other way than due to work performed on the body.

      Some heat goes somewhere, disappearing from the universe forever, because it can no longer be extracted.

      That would be a per se violation of the First Law of Thermodynamics, especially as it concerns the Law of the Conservation of Energy.

      You are right to wonder where that energy goes, but you are wrong to assume that all the energy in every thermodynamic reaction can be reused. Yes, conservation of energy applies. However, entropy increases due to the interaction, and there is no process whereby entropy can be reduced if you look at the system as a whole. This energy that becomes entropy is irrecoverable.

      Keep in mind that when physicists were first observing and measuring the interactions of bodies with temperature, they had to add entropy because the conservation of energy required that the lost energy go somewhere. It wasn’t originally discovered because of statistical calculations, but because of actual observations. That is the way physics works: observe, then reason.

      To sum up, once again, there is no experiment to date that demonstrates the claimed Greenhouse Effect. It simply exists in your imagination and the imaginations of a lot of misguided scientists. This misunderstanding is caused by their inability to see how the Second Law applies to their theories, which you are beautifully demonstrating here. The Second Law applies to every thermodynamic interaction, and is inviolate. Because of the Second Law, a lot of great theories have had to be scrapped and a lot of crackpots have been exposed.

      Heat is not reflected, it is not focused. It only transfers from one system or body to another. That is inarguable.

      And without additional work, heat cannot flow from cold to hot. That is also inarguable.

      The warmth of the earth, radiating as heat, is not reflected back to the earth because of CO2. The earth will not get warmer if more CO2 is added because the heat characteristics of CO2 is that it makes a better heat conductor compared to other atmospheric gasses.

      Until someone can demonstrate the Greenhouse Effect, and explain it in a way that doesn’t contradict the 2nd Law, it doesn’t exist.

  14. tensor Says:

    Arguing that work is not force applied over a distance is not helping your cause.

    I made no such argument. I merely noted how your formulation, “work is any force applied at a distance, at any scale, microscopically or macroscopically”, was wrong. Random forces at the microscopic scale produce heat, not work, and the Second Law limits how much of the first may be turned into the other. (How can you gas on at this length about the importance of the Second Law, and miss this elementary distinction?)

    Please re-read the scientific definition of heat. It differs a little bit from what we call heat colloquially.

    My use of the term ‘heat’ has been completely consonant with thermodynamics throughout this discussion.

    Let me quote from a textbook on the subject, conveniently quoted and cited at Wikipedia:

    Well, you could have just provided a link, but since you didn’t do that (what do you think this is, tensor, a blog?), I’ll have to note from inspection the definition of heat is wrong:

    … heat is the process of energy transfer …

    Dead flat wrong. Heat is not a ‘process’ of any kind whatsoever. It is energy. The rest of the entry is therefore totally worthless.

    You are right to wonder where that energy goes…

    I did no such thing. You claimed it disappeared from the universe; I replied that the heat remained in the material unless it somehow transferred (to another part of the universe). You’re the one left helplessly wondering where it went.

    … you are wrong to assume that all the energy in every thermodynamic reaction can be reused.

    I made no such assumption. Indeed, the Second Law tells us that not all of the energy resident in a system can be recovered as work (I assume this is what you meant by “can be reused”).

    However, entropy increases due to the interaction, and there is no process whereby entropy can be reduced if you look at the system as a whole.

    If you’re referring to a closed system, yes. If the system can obtain energy from the outside, then the entropy within can be reduced via application of work. (However, we have now created a larger system, within which entropy must increase. In the case of earth’s climate, this larger system is the sun, earth, moon, and all of known space. That’s a lot of opportunities to increase entropy outside of the earth, whilst reducing it here.)

    This energy that becomes entropy is irrecoverable.

    Energy cannot become entropy; it can only remain energy, albeit in some other form — heat, work, matter. Entropy is a function of a system. Please stop making this elementary mistake.

    That is the way physics works: observe, then reason.

    We’ve observed the temperature of the earth increasing. We’ve found a reason for it. You’re the one denying all that.

    To sum up, once again, there is no experiment to date that demonstrates the claimed Greenhouse Effect.

    That’s because the physical data more than suffices.

    Because of the Second Law, a lot of great theories have had to be scrapped and a lot of crackpots have been exposed.

    Not every one of them understands his exposure, obviously.

    And without additional work, heat cannot flow from cold to hot. That is also inarguable.

    Yes, that is exactly what I have been saying all along. And the sun provides plenty of workable energy to drive this flow.

    The warmth of the earth, radiating as heat, is not reflected back to the earth because of CO2.

    Of course not. That would make global warming possible, and as you’ve repeatedly said, this is doubleplusunpossible in extremis. QED.

    Heat is not reflected, it is not focused.

    I’ve got an experiment for you. Take a giant concave fun-house mirror, maybe ten feet across, and set it up so the interior curve faces south. Then, on a bright, sunny Summer’s day, stand at the mirror’s focus. If “heat is not reflected, it is not focused,” then you have nothing to fear. Stand there all day. Please.

    • Jonathan Gardner Says:

      I merely noted how your formulation, “work is any force applied at a distance, at any scale, microscopically or macroscopically”, was wrong. Random forces at the microscopic scale produce heat, not work, and the Second Law limits how much of the first may be turned into the other. (How can you gas on at this length about the importance of the Second Law, and miss this elementary distinction?)

      I think you need to back up and review what work and energy really are. What part of my definition of work is wrong? Section 23-7 of HRK contains an interesting discussion of what is happening at the molecular level in a gas. This is hardly uncommon knowledge that physics students who already understand collisions cannot grasp.

      However, all of that is largely irrelevant to the discussion at hand, except to say that radiation is not a magical force that violates any of Newton’s laws.

      My use of the term ‘heat’ has been completely consonant with thermodynamics throughout this discussion.

      I’ve been using the textbook definition of heat, and you’ve been using something else. See Halliday, Resnick and Krane’s textbook “Physics”, 4th Edition, page 547. Or the wikipedia article on “heat”.

      Without agreeing on what heat is, we cannot agree on the 2nd Law, and we will never agree on whether the Greenhouse Effect violates that law.

      Please let me know what you think heat is, and what textbook or source you’ve been using.

  15. tensor Says:

    As I mentioned already, the wikipedia article you cited is worthless, because heat is not a process. The Encyclopedia Britannica defines heat as “energy that is transferred from one body to another as the result of a difference in temperature.” The article on thermodynamics clarifies this a bit: “The key concept is that heat is a form of energy corresponding to a definite amount of mechanical work.” Annoyingly, neither definition introduces entropy, and the attendant irreversibility of converting work to heat, but they’ll do for us here. I claim that everything I’ve written was consonant with these definitions.

    Meanwhile, I’d really like to know what you meant by:

    “Heat is energy transferred (in what form, we can’t say) from something hot to something cold.”

    Why can’t we say? It’s a set of random motions on the microscopic scale. isn’t it? You mentioned the conservation of momentum; if we imagine molecules as little marbles, bouncing off of each other in random directions, endlessly conserving momentum, then we can visualize heat, can we not?

    “Heat is a kind of energy, but not energy in the normal sense.”

    What is the “normal sense” of energy, and how does heat fail to meet this definition? As I mentioned, we’ve found heat everywhere in the universe we’ve looked, which would make it very “normal” indeed, under the lay person’s definition of that word.

    “Heat is not reflected, it is not focused.”

    It seems pretty focused in places like the sun, and in the core of the earth. Legend says Archimedes used giant mirrors to set ships ablaze, and we use this same principle in some solar heat engines. Why do you ascribe to heat the absence of these properties?

    “NOTHING can trap or store heat. That would violate the 2nd Law of Thermodynamics.”

    The very concept of “heat capacity” argues against your first point, and I fail to see how the Second Law prohibits heat storage by a body. If heat cannot be reflected, as you say, and nothing can store it, how then does it transfer from one body to another? One body can’t even store any heat to transfer to another, right?

    You’ve bemoaned the supposed lack of laboratory evidence, but the absorptive and radiative properties of carbon dioxide and methane have been measured in tightly controlled experiments. This is why we call them “greenhouse gasses.”

    Finally, I note that you seem to have a huge amount of trouble with all basic concepts in physics:

    …radiation is not a magical force that violates any of Newton’s laws.

    Again, from the Britannica: ” Nevertheless, Newton’s laws continue to give an accurate account of nature, except for very small bodies such as electrons or for bodies moving close to the speed of light.”

    Radiative heat transfer takes place via photons, usually of the infra-red frequency. As photons are particles of light, and thus move with the speed of light, you managed to pick the only case of heat transfer we’ve been discussing which does indeed not obey Newton’s Laws of motion.

    • Jonathan Gardner Says:

      Why can’t we say?

      The reason we can’t say is because there is too much randomness involved. Was a particular particle influenced by the Van der Waals interaction between two particles? Was it caused by electromagnetic radiation? Who knows? The great thing is we don’t have to know. All of that randomness is summarized quite nicely in the equations, as long as we are ready to sacrifice specificity.

      What is the “normal sense” of energy, and how does heat fail to meet this definition?

      When talking about Energy in Physics, there are really two kinds that are useful. One is Kinetic Energy (KE)—1/2 mv^2. This is the energy of moving particles. The other is Potential Energy (PE), which depends on the force fields or potentials and position of the particle. Normally, you exchange one for the other in a sort of universal economy of energy. As the cart rolls uphil, its PE increases so its KE must decrease in direct proportion. When two charged particles of similar charge approach each other, PE is increased ans so their KE must decrease, and so on and so forth.

      There are other forces and energies at work, but they are annoying and difficult to deal with. For instance, friction. We know from experience that things slow down and eventually stop due to friction. Well, the KE had to go somewhere, and it wasn’t PE, so we have to invent a new bag to throw that energy into. Unfortunately, unlike PE and KE, that energy is not recoverable. That is, we can’t exchange that energy into PE or KE and get the cart rolling again. So this kind of energy is clearly not “normal” because it is a greedy participant in the universal energy economy, always consuming yet never producing.

      Heat is a tricky sort of energy that is imaginary in one way. It represents a transfer of energy (again, of what sort we can’t and won’t say) and some of the energy transferred is lost forever. We don’t treat heat the same way we treat PE or KE (the normal energies) because it doesn’t behave like them at all. Heat goes in one direction, heat can be irreversible, and heat can be lossy.

      “Heat is not reflected, it is not focused.”

      It seems pretty focused in places like the sun, and in the core of the earth. Legend says Archimedes used giant mirrors to set ships ablaze, and we use this same principle in some solar heat engines. Why do you ascribe to heat the absence of these properties?

      You are talking about something that I do not call heat. Of course you are not going to agree with me about its properties because you don’t even agree with me about the definition of the word.

      On Archimedes’ burning ships, can you tell me whether the ships will burn at a temperature greater than or less than the temperature of the surface of the sun? This is important, because he clearly wasn’t adding work to transfer heat from cold to hot.

      The very concept of “heat capacity” argues against your first point,

      Please, please please stop being absurd. As we’ve already covered, heat capacity has nothing to do with storing heat. It describes how quickly a substance changes in temperature according to heat transferred.

    • Jonathan Gardner Says:

      You’ve bemoaned the supposed lack of laboratory evidence, but the absorptive and radiative properties of carbon dioxide and methane have been measured in tightly controlled experiments. This is why we call them “greenhouse gasses.”

      Absorption and reflection have very little to do with thermal resistance.

      Please cite your sources. I am very interested in measurements of the heat properties of CO2, not its radiative properties. As I’ve already described, whether or not a material absorbs or reflects certain wavelengths of light has little to do with its heat properties and cannot create a substance that will not transfer heat nor violate the 2nd Law of Thermodynamics.

      Radiative heat transfer takes place via photons, usually of the infra-red frequency.

      As I’ve said before, an analysis of the forces and energies transferred during heat exchange will not give you an accurate picture of how the systems transfer heat. That is why you have to consider things at a different scale and entirely ignore whether energy is transferred via one process or another.

  16. tensor Says:

    I’ve been using the textbook definition of heat, and you’ve been using something else.

    Please give that definition of heat (your link went only to the Amazon.com ad for the book), and show how it supports the many statements you’ve here made:

    Heat is an imaginary energy that sums up all of the interactions between two systems.

    NOTHING can trap or store heat.

    Heat is not reflected, it is not focused.

    Heat is a kind of energy, but not energy in the normal sense. It’s a magical kind of energy that doesn’t exist at a molecular level. It obeys a whole different set of laws.

    “[Heat] seems pretty focused in places like the sun, and in the core of the earth.”

    You are talking about something that I do not call heat.

    What do you call heat? Please give us your definition.

  17. tensor Says:

    The wikipedia definition is not good enough, because it calls heat a “process”. Heat is energy.

    You cited (but did not quote) the definition of “heat” from a textbook. Please quote that full definition here, and show how your interesting statements about heat storage follow from that definition. (You may also wish to quote that textbook’s definition of “calorie”, as it most certainly pertains to heat capacity.)

    • Jonathan Gardner Says:

      OK, one more comment and then I’m really done with this topic.

      HRK, 4th edition, volume 1 pp 547-8: “Heat is energy that flows between a system and its environment by virtue of a temperature difference between them.” “Heat is similar to work in that both represent a means of the transfer of energy. Neither heat nor work is an intrinsic property of a system; that is, we cannot say that a system “contains” a certain amount of work or heat.”

      Wikipedia is absolutely correct, because energy that flows is a process.

      Now seeing as how I am using the textbook definition of heat, and you are using something else, it stands that I am correct and you are not. There is no such thing as the Greenhouse Effect because it would violate the 2nd Law of Thermodynamics if it existed and because it has never been observed.

      A calorie is a measure of energy or work. 1 cal = 4.19 J. (Food labeling, I believe, uses a different unit for calories the Calorie, which is 1000 calories. Confusing? Yes.

  18. Fred Staples Says:

    Tensor, how John Gardner has the patience I cannot imagine.

    Next time you pass a power station, have a look at tthe cooling towers, and ask yourself what they are for.

    Then ask how we could make use of that waste energy. Recycle it through the turbines? No. Warm up a cold house? Possibly.

    One vaguely similar parallel that occurs to me is Newton’s law of action and reaction. Push hard against a wall, and you will feel the wall push back. Now consider the push and the reaction separately. Be careful though. If you push too hard the wall will push you over.

    Most of what is written to justify AGW is second law violating nonsense.

    The only exception is the “higher is colder” theory that depends on the lapse rate. The lapse rate is a pressure phenomenon which depends on specific heat and gravity – nothing to do with radiation, or atmospheric content for that matter.

    The idea is that additional CO2 in the (dry) upper atmosphere impedes radiation to space, and the effective emission point move up to higher altitudes, which are colder. The rate of energy emission is reduced (fourth power law), incoming energy does not change, so everything warms up to compensate.

    It is at least plausible. Is it true? I don’t know. The evidence is against it, and it is never quantified, but it is difficult to disprove.

  19. Jackson Says:

    Wow. I randomly encountered this page whilst looking for something else. It’s a good thing that neither Jonathan Gardner nor Fred Staples are in positions where they make energy policy. As Jonathan Gardner correctly points out “…we know that when the earth is cold and the sun is hot, the vast majority of photons do increase the temperature of the earth.” However, “as the earth warms, more and more photons are actually cooling the earth” is not correct. In any case “If the earth were to reach the same temperature as the sun, then the energy flowing from the sun would neither heat nor cool the earth” is correct, but if you check the temperature of the Earth currently and the temperature of the Sun currently, you might figure out that we will have no discussions of global warming, or anything else if the temperature of the Earth were to equal the temperature of the Sun. Fortunately, there is no known mechanism for that to happen in the next 5 billion years. Global warming is concerned with ones or tens of degrees. Warming the Earth to the Sun’s temperature is a change of millions of degrees.

    And, Mr. Staples, good luck with getting the wall to push you over. Equal and opposite means that the net acceleration is zero.

    • Jonathan Gardner Says:

      There is some semblance of logic here, worthy of a reply.

      So you have two statements you agree with: (a) “When the earth is cold and the sun is hot, the vast majority of photons increase the temperature of the earth” (b) “If the earth were to reach the same temperature as the sun, then the energy flowing from the sun would neither heat nor cool the earth.”

      And one you don’t agree with: (c) “As the earth warms, more and more photons are actually cooling the earth”.

      I don’t see how you can have (a) and (b) be true without (c) being true also. Note carefully, I am not saying “all” photons cool the earth. I am only saying that some photons heat and some photons cool, and that the proportion changes as the relative temperatures change. We both agree on two extremes (a) and (b), but you disagree that (c) lies between the two.

      I don’t know what relevance your bringing up the fact that if the earth were the temperature of the sun, it would be very, very hot. Red herring.

      • Jackson Says:

        Jonathan: You are being charitable finding a semblance of logic there.

        Perhaps I misspoke by saying that a vast majority of the photons from the sun increase the temperature of the earth. More precisely, all photons from the sun (or anywhere else) add energy to the earth, with the net energy gain (or loss) being a function of the energy of the photons received minus the energy of the photons released [simply because photons cannot have negative energy]. I used “vast majority” instead of “all” because there is a (vanishingly) small probability that a set of photons from the sun might interact with the earth such that the energy of ejected photons is greater than the energy of the absorbed photons. My guess is that this probably happens less than once a day over the entire surface of the earth and can thus be ignored.

        Since the net gain (or loss) of energy from photon emission and absorption is a function of how many photons of what energy are emitted, it is relevant to compare the relative temperatures of the sun and earth. The sun’s surface is around 5700 kelvin, while the earth’s surface is everywhere below 350 kelvin (the max recorded). The ill effects of climate change, if you believe all of the science behind it, would occur with just less than a 10 kelvin difference. So, if we’re trying to figure out, as a society, how to deal with a potential movement from 300 kelvin to 310 kelvin, we don’t have to discuss the case of what happens when the earth’s surface reaches 5700 kelvin.

      • Jonathan Gardner Says:

        I think you’re missing the point altogether.

        There is a statistical interpretation of thermodynamics that reduces the thermodynamic laws into classical statistical mechanics. It does not, however, contradict it, and your poor understanding of how the connection is made doesn’t make you right to interpret things in the way you have.

        In other words:

        You can choose to look at thermodynamics in terms of pressure, volume, temperature, heat, and such. Under this interpretation, the methods of heat transfer are irrelevant and do not change the results. All you need to know is whether heat transfer occurs at all and by how much. We have already measured the thermodynamic properties of CO2, and we have already made the measurements otherwise. No Greenhouse Effect exists.

        Or, you can choose to look at particles and energy and momentum. Under this interpretation, you can think about radiation and such, but you must also consider all other forms of energy transfer. This system inevitably reduces to the previous system of pressure, volume, temperature and heat, without contradiction. If it did contradict it, then the statistical interpretation would be wrong, not the other way around.

        You must admit that an energetic particle from one system does not necessarily transfer its kinetic energy or momentum to another system. You must include the probability of whether that particle ends up gaining or losing momentum from a more or less energetic particle in the other system. As such, you must also admit that radiation — the interaction between two particles of two systems — does not contradict this result. If you, instead, think of the radiation as something separate, it still cannot contradict this. If it does, your ideas are wrong, not thermodynamics.

        Thinking in terms of the second, statistical mechanical interpretation is very, very difficult. It took a long time before all the details were hammered out and the experimental results that gave us the first interpretation were derived. Notice I say “derived”. The first interpretation is based solely on observation and a little bit of math. The second interpretation is all theory, with a little bit of observation (Brownian Motion and such, for instance.) If the second interpretation does not agree with the first, then the second is wrong, not the other way around.

        In neither case can you analyze a thermodynamic system, such as the earth, by exclusively analyzing one method of heat transfer when other methods of heat transfer are known to occur. You have to measure the temperature of the sun, the temperature of the earth, and the heat transfer between the two.

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