Guest Post by Willis Eschenbach
Figure 1. The Experimental Setup
I keep reading statements in various places about how it is indisputable “simple physics” that if we increase the amount of atmospheric CO2, it will inevitably warm the planet. Here’s a typical example:
In the hyperbolic language that has infested the debate, researchers have been accused of everything from ditching the scientific method to participating in a vast conspiracy. But the basic concepts of the greenhouse effect is a matter of simple physics and chemistry, and have been part of the scientific dialog for roughly a century.
Here’s another:
The important thing is that we know how greenhouse gases affect climate. It has even been predicted hundred years ago by Arrhenius. It is simple physics.
Unfortunately, while the physics is simple, the climate is far from simple. It is one of the more complex systems that we have ever studied. The climate is a tera-watt scale planetary sized heat engine. It is driven by both terrestrial and extra-terrestrial forcings, a number of which are unknown, and many of which are poorly understood and/or difficult to measure. It is inherently chaotic and turbulent, two conditions for which we have few mathematical tools.
The climate is composed of six major subsystems — atmosphere, ocean, cryosphere, lithosphere, biosphere, and electrosphere. All of these subsystems are imperfectly understood. Each of these subsystems has its own known and unknown internal and external forcings, feedbacks, resonances, and cyclical variations. In addition, each subsystem affects all of the other subsystems through a variety of known and unknown forcings and feedbacks.
Then there is the problem of scale. Climate has crucially important processes at physical scales from the molecular to the planetary and at temporal scales from milliseconds to millennia.
As a result of this almost unimaginable complexity, simple physics is simply inadequate to predict the effect of a change in one of the hundreds and hundreds of things that affect the climate. I will give two examples of why “simple physics” doesn’t work with the climate — a river, and a block of steel. I’ll start with a thought experiment with the block of steel.
Suppose that I want to find out about how temperature affects solids. I take a 75 kg block of steel, and I put the bottom end of it in a bucket of hot water. I duct tape a thermometer to the top end in the best experimental fashion, and I start recording how the temperature changes with time. At first, nothing happens. So I wait. And soon, the temperature of the other end of the block of steel starts rising. Hey, simple physics, right?
To verify my results, I try the experiment with a block of copper. I get the same result, the end of the block that’s not in the hot water soon begins to warm up. I try it with a block of glass, same thing. My tentative conclusion is that simple physics says that if you heat one end of a solid, the other end will eventually heat up as well.
So I look around for a final test. Not seeing anything obvious, I have a flash of insight. I weigh about 75 kg. So I sit with my feet in the bucket of hot water, put the thermometer in my mouth, and wait for my head to heat up. This experimental setup is shown in Figure 1 above.
After all, simple physics is my guideline, I know what’s going to happen, I just have to wait.
And wait … and wait …
As our thought experiment shows, simple physics may simply not work when applied to a complex system. The problem is that there are feedback mechanisms that negate the effect of the hot water on my cold toes. My body has a preferential temperature which is not set by the external forcings.
For a more nuanced view of what is happening, let’s consider the second example, a river. Again, a thought experiment.
I take a sheet of plywood, and I cover it with some earth. I tilt it up so it slopes from one edge to the other. For our thought experiment, we’ll imagine that this is a hill that goes down to the ocean.
I place a steel ball at the top edge of the earth-covered plywood, and I watch what happens. It rolls, as simple physics predicts, straight down to the lower edge. I try it with a wooden ball, and get the same result. I figure maybe it’s because of the shape of the object.
So I make a small wooden sled, and put it on the plywood. Again, it slides straight down to the ocean. I try it with a miniature steel shed, same result. It goes directly downhill to the ocean as well. Simple physics, understood by Isaac Newton.
As a final test, I take a hose and I start running some water down from the top edge of my hill to make a model river. To my surprise, although the model river starts straight down the hill, it soon starts to wander. Before long, it has formed a meandering stream, which changes its course with time. Sections of the river form long loops, the channel changes, loops are cut off, new channels form, and after while we get something like this:
Figure 2. Meanders, oxbow bends, and oxbow lakes in a river system. Note the old channels where the river used to run.
The most amazing part is that the process never stops. No matter how long we run the river experiment, the channel continues to change. What’s going on here?
Well, the first thing that we can conclude is that, just as in our experiment with the steel block, simple physics simply doesn’t work in this situation. Simple physics says that things roll straight downhill, and clearly, that ain’t happening here … it is obvious we need better tools to analyze the flow of the river.
Are there mathematical tools that we can use to understand this system? Yes, but they are not simple. The breakthrough came in the 1990’s, with the discovery by Adrian Bejan of the Constructal Law. The Constructal Law applies to all flow systems which are far from equilibrium, like a river or the climate.
It turns out that these types of flow systems are not passive systems which can take up any configuration. Instead, they actively strive to maximize some aspect of the system. For the river, as for the climate, the system strives to maximize the sum of the energy moved and the energy lost through turbulence. See the discussion of these principles here, here, here, and here. There is also a website devoted to various applications of the Constructal Law here.
There are several conclusions that we can make from the application of the Constructal Law to flow systems:
1. Any flow system far from equilibrium is not free to take up any form as the climate models assume. Instead, it has a preferential state which it works actively to approach.
2. This preferential state, however, is never achieved. Instead, the system constantly overshoots and undershoots that state, and does not settle down to one final form. The system never stops modifying its internal aspects to move towards the preferential state.
3. The results of changes in such a flow system are often counterintuitive. For example, suppose we want to shorten the river. Simple physics says it should be easy. So we cut through an oxbow bend, and it makes the river shorter … but only for a little while. Soon the river readjusts, and some other part of the river becomes longer. The length of the river is actively maintained by the system. Contrary to our simplistic assumptions, the length of the river is not changed by our actions.
So that’s the problem with “simple physics” and the climate. For example, simple physics predicts a simple linear relationship between the climate forcings and the temperature. People seriously believe that a change of X in the forcings will lead inevitably to a chance of A * X in the temperature. This is called the “climate sensitivity”, and is a fundamental assumption in the climate models. The IPCC says that if CO2 doubles, we will get a rise of around 3C in the global temperature. However, there is absolutely no evidence to support that claim, only computer models. But the models assume this relationship, so they cannot be used to establish the relationship.
However, as rivers clearly show, there is no such simple relationship in a flow system far from equilibrium. We can’t cut through an oxbow to shorten the river, it just lengthens elsewhere to maintain the same total length. Instead of being affected by a change in the forcings, the system sets its own preferential operating conditions (e.g. length, temperature, etc.) based on the natural constraints and flow possibilities and other parameters of the system.
Final conclusion? Because climate is a flow system far from equilibrium, it is ruled by the Constructal Law. As a result, there is no physics-based reason to assume that increasing CO2 will make a large difference to the global temperature, and the Constructal Law gives us reason to think that it may make no difference at all. In any case, regardless of Arrhenius, the “simple physics” relationship between CO2 and global temperature is something that we cannot simply assume to be true.
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Harry Eagar (11:09:30): Edward Lorenz (in the Danz Lectures) said he didn’t know whether it was or not.
This does not really matter. What matters is that our understanding of the climate involves mathematical equations, namely the Navier-Stokes equations, are known to be chaotic in nature.
The Navier-Stokes equations for fluid flow are at the heart of climate models.
http://physicsworld.com/cws/article/print/26946
To be frank, we can never prove that anything is chaotic. The reason is that we can never observe anything with the sufficient accuracy. In a strict mathematical sense, chaos is, as beauty, in the eye of the beholder.
However, we can suspect that weather and climate is chaotic by the power scale invariance that is characteristic for both our climate and the Navier-Stokes equations that is our understanding of it.
JP (10:44:16)
See my WUWT post on this subject here.
ThinkingBeing (10:02:11) :
“You belittle all of climate science by acting like scientists are oh so silly and foolish to not see the obvious that you and yours can see.”
The point of the post is to provide a basis by which non-technically oriented people may grasp that complex systems behave in anti-intuitive ways. It is not that the climate scientists do not understand that they are dealing with a complex system, it is that they are selling it to lay people as being simple and straightforward, when it is not.
Was that really so difficult for you to understand?
@Allan M (12:05:52) :
“Q: Eighty percent of the heat radiated back from the surface is absorbed in the first 30 feet by water vapor…”
The greenhouse effect is determined by the temperature difference of the earth and the gas emitting the infrared radiation to outer space. The first 30 feet of the earth has about the same temperature as the earth, so it radiates at the same intensity. No greenhouse effect there.
The temprature of the highest gas in the atmosphere absorbing a certain frequency of infrared determines the actual radiation to outer space for that frequency. Since CO2 is located high in the atmosphere where it is colder, it radiates less intense then the earth, thus resulting in an greenhouse effect.
Hank Henry (11:03:07)
Not so. Consider a pan of water. There is a basic principle that if we turn up the heat under the pan, there “must be a degree of warming” of the water. Which works well up to a point, that point being the boiling point of water. At that point, all of the heat is going into evaporation, and despite the simplistic claim that “there must be a degree of warming”, the water doesn’t warm.
Now, this is exactly what happens with the oceans. There is no part of the ocean on the planet which is much warmer than 30C. Why not? Same reason. At a certain point, the increased energy input to the ocean (from any forcing, solar, CO2 whatever) just increases the evaporation and the clouds and the thunderstorms, so the ocean doesn’t get any warmer. See my post on this subject here.
I say again, “simple physics” doesn’t apply to complex systems.
Ref Anna V
Hear hear.
Could not agree more about the failure of such modelling, which is why of course unless you impose constraints which don’t exist in the real world, the model collapses into a puddle by slamming over to its limits quite quickly: from what I understand usually about 3 to 6 months. No matter the thing is useless even if you could estimate the probability of the reliability of the forecast, which effectually you cannot, It would still be useless in terms of predicting outcomes in the longer term, that is years.
As recent studies have shown, the various models simply don’t work. Their predictive power measured against each other turns out to be zero. You would do as well if not better with my beautiful ancient tarot cards, which I got back from the restorer just before Christmas. And don’t even ask how much he charged.
As to use of analogue computing about which I know something it would do a much better job than digital techniques because of its speed, with a suitable set up you could compare in a year not millions of runs but billions and tens of billions of them.
Moreover you would have a much better idea of the sensitivity of the model to slight changes than digital machines can offer. And technically there would be no problem today of building such a machine.
But I am far from sure in the end it would get you anywhere. There is so much we do not know about the climate system and its complexities that I for one cannot see how it can be modelled at the moment.
We simply do not understand enough about the great natural forces that drive the climate. Perhaps we never will.
But of this I am certain, those who proclaim that they can predict the climate and endorse the AGW effect exhibit an astonishing mixture of arrogance and ignorance.
Kindest Regards
Harry Eagar (11:09:30): Edward Lorenz (in the Danz Lectures) said he didn’t know whether it was or not.
This does not really matter. What matters is that our understanding of the climate involves mathematical equations, namely the Navier-Stokes equations, which are known to be chaotic. The reason this is important is that climate models may then be unable to predict our climate.
The Navier-Stokes equations for fluid flow are at the heart of climate models.
http://physicsworld.com/cws/article/print/26946
To be frank, we can never prove that anything is chaotic. The reason is that we can never observe anything with the sufficient accuracy. In a strict mathematical sense, chaos is, as beauty, in the eye of the beholder.
However, we can suspect that weather and climate is chaotic by the inverse power law scale invariance that is characteristic for both our climate and the Navier-Stokes equations that is our understanding of it.
“This article is ridiculously disingenuous. To start, it implies that climate science applies “simple physics” with no consideration for complexity, like a child thinking that anything that is brown is chocolate. It’s not true, and you know it. You belittle all of climate science by acting like scientists are oh so silly and foolish to not see the obvious that you and yours can see.”
Saying “The Science Is Settled” is a wee bit simplistic, is it not? Not to say ridiculously disingenuous.
Oh, and a lie.
[snip – no valid email address “a@a.com” not valid – see policy page]
I’ll go one better (more simple) than this. What is the definition of global temperature? If one postulates global warming one needs to know what global temperature is. I remember a couple years back when I became quite suspicious of Global warming when Al Gore wouldn’t shut his yap about it that I tried to ask this question on a different board and was referred to as a mass murderer for trying to define terms. I had hoped for a discussion of different temperature data sets, the understanding that these data sets are only a small sample of the Earth’s temperature at any one time, the limitiations, precision and accuracy of the data, how the methodology for sampling temperature may have altered over years, decades, centuries. Never got that far of course, but even saying one knows global temperature with any degree of accuracy needs to be demonstrated. From there can one determine with any confidence, given changes in methodology, past trends in temperature. From there can one make predictive models of temperature change (and have they been confirmed!!) especially on the scale of decades and centuries, as this seems to be the idea underlying much of “the sky is falling, the sky is falling … give us your money” political discourse of late. If one ever confirmed that future temperature trends were accurately being predicted, would one have any confidence that they understood the underlying causes and from there the necessary changes (ie the “give us your money” part). Funny that the solution proffered to a postulated future trend in global temperature, is an attempt at man-made global cooling.
Finally, one should recognize when surrogates are being used in place of actual temperature readings, i.e. tree ring data might reflect not just temperature but for instance CO2 concentration, coral reefs, local predator populations, ice cover, ocean salinity and ice particulate content etc, etc.
I would think given the complexity of the climate the last thing anyone would want is some global treaty to attempt anthropogenic climate change.
[snip – no valid email address “a@a.com” not valid]
“The question is not whether something is happening. It is whether CO2 is the secret global thermostat that adjusts the earth’s temperature … which is a much harder question to answer. In particular, it cannot be answered by “simple physics”.”
Of course not, that’s why we have GCMs. If it could be answered by simple physics then GCMs would be unnecessary.
Simple physics alone show significant warming from a doubling of co2. The point there being that co2 caused warming isn’t just some myth invented by politicians, it has a physical basis, it’s a result that requires detail to dismiss – even if that can be done. A scientist would ask why a 3.7wm-2 radiative imbalance caused by a doubling of co2 would result in no increase in temperature?
If we want to get no warming from a doubling of co2 we require the forcing to be completely offset by an increase in albedo, possibly by reducing sunlight reaching the Earth. But such an increase in albedo and reduction in absorbed sunlight is a climate change causedin itself. Either way doubling co2 causes significant climate change. There’s no way of getting around this and it’s why co2 is such an issue.
Willis
So if there is any warming from CO2, it is likely to be considerably less than 0.3K per doubling … and that’s my “it’s too small” argument.
What’s wrong with these calculations then?
http://www.sciencebits.com/OnClimateSensitivity
@Willis Eschenbach (12:52:28) :
How come the thermostat in your article could not prevent the glacial – interglacial temperature difference of about 6C
“PD (13:10:58) :
…
I would think given the complexity of the climate the last thing anyone would want is some global treaty to attempt anthropogenic climate change.”
Governments want a global treaty so that they can print carbon permits and auction them off. It’s a new kind of money.
Okay, but how do you explain the Hiller???
Dave UK
Which planet are you on. The media thrives on bad news and alarmism – plane crashes, end of the world etc. Don’t try and confuse them with boring facts. Thats why they are slowly going out of business.
Sadly, people do not understand greenhouses. The energy comes in through the windows of the greenhouse, gets absorbed by what is in it and the stuff radiates according to Plank’s Law. What does not happen in a greenhouse is convection of the heated air in the greenhouse to the cooler air outside the greenhouse. The use of the word greenhouse in relation to IR absorbent materials is close to a fraud. People have walked into their various gardening store greenhouses and then think that CO2, etc. work the same way. Nothing could be further from the truth. To call CO2, CH4, etc. greenhouse gasses is a perversion of the meaning of greenhouse so that the AGW folks can sell the concept to people with the brains of a slime mold, i.e. other AGW folks. That is not to say that CO2 cannot cause lower atmospheric warming. But the propaganda minster Mr. Al Goebbels has repeated the untruth so often that trying to explain what is really going on with the equations of radiative transfer, convection, and all the rest. And that is even before we get to things like the AMO, PDO, volcanoes, sunspots and so forth.
Personally I would love to see Gorge hauled up on a RICO and reduced to penury.
“cthulhu (13:21:16) :
[…]
Of course not, that’s why we have GCMs. If it could be answered by simple physics then GCMs would be unnecessary.
[…]If we want to get no warming from a doubling of co2 we require the forcing to be completely offset by an increase in albedo, possibly by reducing sunlight reaching the Earth. But such an increase in albedo and reduction in absorbed sunlight is a climate change causedin itself. ”
1.) Current GCMs don’t include clouds.
2.) Clouds change the albedo, see Willis’ post:
http://wattsupwiththat.com/2009/06/14/the-thermostat-hypothesis/
–> The current GCM’s are useless to explain the energy balance.
There are more reasons why AGW is all a wacked mockery of science but this suffices to discard the GCM’s. It’s a pity. So much work and all for nothing.
“DirkH (13:47:16) :
It’s a pity. So much work and all for nothing.”
And i’m NOT being sarcastic here. I’m a computer programmer and i love a good simulation. I really hoped these guys were on to something.
J.Peden (10:40:05) :
“Ok, if what you just said is correct, why hasn’t water vapor alone already done the same thing? Why does CO2 do what water vapor couldn’t do? If water vapor alone couldn’t do what CO2 does, why would water vapor help CO2?”
The answer to these questions are available to anyone that bothers to do a little research, and has the basic scientific education to understand what they read. If you don’t know the answers to these questions, you disqualify yourself from the right to debate the issue.
Galen Haugh (10:21:59) :
“So you’re saying these “models” of yours can forecast anything when they can’t even backcast anything?”
No, I never said any such thing and you know it. First, they can’t forecast anything, but they can reliably forecast an increase in temperatures due to CO2. Secondly, they can “backcast” things, and doing so is one technique used to validate the models.
Jim (10:46:21) :
“I get the “being” part. But I’m not seeing much thinking.”
Ah, pointless, empty insults. Perfect.
Invariant (10:48:01) :
“How do you know that climate models are useful when they only reproduce the observations they are based on?”
This statement is false, hence the question is meaningless. The models do not “only reproduce the observations they are based on.” The models incorporate known complex physical (and sometimes statistical) relationships in an attempt to confirm the correctness of the underlying physical model, and then to project the general outcomes of specific parametric changes. But I’m not going to argue the validity of the models on these pages with anyone here. This is the land of zealots who have already made up their minds, then, with their minds closed, have chosen to very heroically label themselves as “skeptics.” So there’s no way to educate them, and no point in trying.
Hank Henry (11:03:07) :
“I also believe that most of the direst predictions result from speculations about positive feedbacks such as increases in methane from melting permafrost and reduced albedo due to lessened snow cover.”
This is not true. The predictions come from the very simple fact that an increase in CO2 will raise temperatures 0.5C, and an increase of 0.5C in temperature will increase the amount of moisture in the atmosphere in a way that will increase temperatures by another 3C (which no, does not further increase temperatures… the effects are not simple and additive, and the 3C already takes into account any such progression). Changes in surface albedo and the such are things that are NOT included in the 3C, and as such are an area of additional difficulty if they should kick in.
“I can speculate too though. Perhaps there is a homeostatic “iris effect” at work where warmer temperature makes for more clouds and more clouds make for less sunlight and less sunlight makes for less insolation – resulting in a cooling effect.”
And this is the magic I was talking about. Speculation, because you’d like it to be so. Lindzen has been saying this for decades without being able to prove it would happen. It would be nice, but it’s a hope and a prayer, not science.
Willis Eschenbach (12:37:06) :
“I won’t and don’t discuss science with anyone who calls me a liar. I may very well be wrong, I’ve been wrong many times before, but I am an honest man. Please take your slimy accusations elsewhere, all you have revealed here is the paucity of your arguments.”
And I have no interest in discussing science with you, not because you may be wrong, but because I believe that you are purposely misleading people. This analogy, and many others, are gravely flawed, and I believe you know it, but you have a personal agenda aimed at sewing confusion about climate science and global warming, and you pursue it with pseudo science that impresses the willfully ignorant.
As to revealing the “paucity of my arguments”… how so? I’m wrong simply because you say I’m wrong? Hooray for you. Well done.
Willis Eschenbach (12:52:28) :
“Now, this is exactly what happens with the oceans. There is no part of the ocean on the planet which is much warmer than 30C. Why not? Same reason. At a certain point, the increased energy input to the ocean (from any forcing, solar, CO2 whatever) just increases the evaporation and the clouds and the thunderstorms, so the ocean doesn’t get any warmer. See my post on this subject here.
I say again, “simple physics” doesn’t apply to complex systems.”
Please provide links to your posts on this, but off the top of my head, your argument above is silly. The ocean is no where close to absorbing all of the heat it is capable of absorbing, but it has absorbed an incredible amount of additional heat in the last twenty years. Comparing the oceans to a pot of water that has reached boiling point? Are you serious? This is such a weak understanding of physics and science that I am now appalled that I ever bothered to post a comment on your post. It’s beneath me.
And again, it’s not “simple physics,” it’s applicable physics and science. Your constant attempts to label it as simple just to make climate scientists sound childish is, itself, further proof of how disingenuous you are.
Hmm,
The behaviour of a small dust devil is chaotic but scale it up to a hurricane sized object that moves slowly wrt to an observer and the behaviour becomes non chaotic, and somewhat predictable.
And if you use the equations of Lorentz and Maxwell to model an hurricane, then, like a spiral galaxy, the modeling works (Peratt’s particle-in-cell mtehod). But use solar powered thermal drivers then you have the mess associated with chaotic behaviour associated with the Navier-Stokes equations. And of course the obvious fact that during night time the solar driver disappears, raising the question of how a hurricane could maintain its state.
MrAce (12:47:32) :
@Allan M (12:05:52) :
“Q: Eighty percent of the heat radiated back from the surface is absorbed in the first 30 feet by water vapor…”
I was merely quoting “the Father of Climatology.” But, sadly, you can’t take it up with him anymore.
The greenhouse effect is determined by the temperature difference of the earth and the gas emitting the infrared radiation to outer space. The first 30 feet of the earth has about the same temperature as the earth (Why?), so it radiates at the same intensity. No greenhouse effect there.
The temperature of the highest gas in the atmosphere absorbing a certain frequency of infrared determines the actual radiation to outer space for that frequency. Since CO2 is located high in the atmosphere where it is colder, it radiates less intense then the earth, thus resulting in an greenhouse effect.
Since CO2 is located high in the atmosphere…
And everywhere else too.
Having been a visitor to this site for several years now, I have come across most of the arguments.
This is an excellent post. I will highlight a further example where “simple physics” doesn’t suffice, from my own work at Sandia National Labs. You might think that “simple physics” are involved in running a huge current through a small cylindrical array of wires, causing them to vaporize and collapse into eachother. (This collapse produces x-rays which are used for fusion generation)
“Oh, that’s simple attraction of current-carrying wires. Any set of parallel wires you run current through will attract!” Yes, but that does not accurately represent what’s going on *in this case*. Back in reality, the wires have a measurable thickness, and varying density, so the outer parts of a wire vaporize before the inner parts, and some sections vaporize faster than others. Different parts of the plasma move toward the center at different speeds and reach the center at different times, and various turbulent phenomena occur in the plasma to break the simple symmetry and reduce the final effect. None of that is noticed by a “simple physics” analysis, but is necessary for the practical purposes.
Simple physics is simply useless for anything but introductory education.
Further to (13:55:07)
MrAce (12:47:32)
Always, always, always the radiative explanations. Like a band that can only play one tune.