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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In reading this post I immediately thought of my area of specialty- economics- and my belief that most economics vastly under-models the complexity of emergent and chaotic systems, and operates at a level of mathematics that comforts those that seek certainty but annoys those that seek truth.
I’m about to go looking, but does anyone have Constructal Law application in the field of economics?
The Unbearable Complexity of Climate.
Exceeded only by the Unbearably Absurd Linear Climate Predictions of the IPCC and their list of clueless subscribers of the models.
If ever there was a clear choice of agencies to cut funding for, the subscribers have recently stuck out like a sore thumb.
to be clear: Climate is now the great menace or boon, as the case may be, since civilisation has exhausted every other conceivable ideology and political creed.
It seems people en masse need a cause and a doom scenario that can be fought for, whether imaginary or not, although the purpose is generaly considered to be finer than the reality behind it.
Originally I stated:
“A lot of hydrothermal activity goes on at these spreading centers. The process involves downward migration of ocean water through the broken basalt along the flanks of the spreading centers and expulsion of that water as heated, mineral-rich hydrothermal fluids adjacent to the spreading axis in a continuous flow.”
Which got this response:
Louis Hissink (22:15:02) :
“Er, no, the water cycle as envisaged by standard plate tectonics theory requires the suspension of gravity for starters, (less dense matter cannot descend into more dense matter), and it is more likely that the water coming out of the spreading ridges comes from the asthenosphere itself. Remember that igenous quartz crystals of the milky white color contain water in their crystal lattices – quartz without water is transparent – like a wine glass or the glass thermometer Willis used in his personalised experiment…”
So my responses are:
Response: Any theory that requires “suspension of gravity for starters” is a non-starter; it obviously doesn’t apply to the real world. Basalt formed and cooled at the spreading ridges is highly fractured and very porous (remember columnar basalt?)—the seawater in which it finds itself is heavier than this same water that is heated by contact with the hot or molten basalt, which sets up major convective cells involving seawater.
Response: If “it is more likely that the water coming out of the spreading ridges comes from the asthenosphere itself”, the volume of the ocean would double in about 8 million years, which flat out doesn’t happen.
Response to: “Remember that igenous quartz crystals of the milky white color contain water in their crystal lattices”. Problem with that argument is that mid-oceanic ridge basalt (MORB) contains precious little quartz (they are unsaturated with respect to SiO2), so it cannot be invoked as a transfer mechanism.
That there is some virgin water from the asthenosphere added to the ocean is not argued, but seawater water takes the dominant role in transferring copious amounts of heat (and minerals) from MORB to the overlying oceans. As long as the spreading center is found in the ocean, the system is innundated with seawater at fairly high pressures.
What virgin water is introduced from the asthenosphere at the spreading centers is balanced with that consumed as the oceanic plate is taken back into the asthenosphere along subduction zones; much of the incorporated water is expelled in the subduction process because the ocean volume has remained fairly steady for much of earth’s history.
And sorry to disappoint Al Gore—but there are no naturally-occurring temperatures approaching millions of degrees anywhere in the earth. That’s another fantasy he entertains, apparently.
Might not the five major subsystems, “atmosphere, ocean, cryosphere, lithosphere, and biosphere” be better described as “atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere” because (a) there are important large bodies of water which are not marine and (b) it sounds niftier?
Richard Patton (23:40:56) :
Tsonis et al, a paper discussed here, made an analogue neural net of the climate assuming deterministic chaos, and gave predictions using the ocean and air current cycles. Their model foresees a cooling/stasis.
Les Francis (et al.):
but see: http://www.news.cornell.edu/releases/March00/APS_Wang.hrs.html:
Louis Hissink (01:18:22) :
re. dust devils and electricity, I don’t see the connection?
I would have thought a dust devil is an air vortex induced by a rapidly ascending parcel of warm air, caused by localised heating of ground layer air by the sun. Commonly seen in rangelands.
Great explanation Willis.
I am boned up on the political arguements about AGW but not the science so much.
I would suggest like myself that everyone who reads WUWT writes to your local/national newspapers letters section and express your doubts about AGW.
I get published quite a lot.
Nobody wants bad news and that is all the ‘Warmists’ have got to offer.
We sceptics however, have good news for the majority to hear.
Get writing.
Recently (DEC 09), Gavin Schmidt has even ramped up his estimates of CO2’s climate sensitivity. Because they can’t explain the Pliocene warm period any other way.
http://www.nature.com/ngeo/journal/v3/n1/abs/ngeo706.html
This is a risky bet on their part. If current climate doesn’t get really warm real soon now, their models will break even harder than they did in the past. Now if you’re a politician funding them toying around there and the results get ever more unbelievable how long will you go on footing their bill?
magicjava (20:46:54) :
The Illuminati fighting to death in favor of “settled science”?
Wikipedia Woes –
Pending Crisis as Editors Leave in Droves
http://www.thunderbolts.info/thunderblogs/davesmith_au.htm
I think the solution would be to allow articles from dissenting authors on a same topic.
You did an excellent job of explaining the complexity of the world’s climate system. This is probably why the AGW advocates use computer climate models. Nature is messy. It doesn’t always behave as one expects. When the unexpected happens, one needs to re-evaluate ones hypothesis and go where the data leads. Computer models, once fully debugged, are clean. With them, you define the rules. There are no surprises. Computer models are great investigative tools, but there is no way one can consider the output from climate models evidence.
The IPCC not only presents the results of climate models as evidence, but states, “The fact that climate models are only able to reproduce observed global mean temperature changes over the 20th century when they include anthropogenic forcing, and that they fail to do so when they exclude anthropogenic forcing, is evidence for the influence of humans on global climate.” (IPCC-Working Group 1, The Physical Basis of Climate Change, 9.4.1.2, p684). ). The IPCC is actually saying that the absence of evidence of natural causes of the climate change is actually “evidence for the influence of humans on global climate.” This logical contortion is best described in Wikipedia, “The argument from ignorance, also known as argumentum ad ignorantiam (“appeal to ignorance”), argument by lack of imagination, or negative evidence, is a logical fallacy in which it is claimed that a premise is true only because it has not been proven false, or is false only because it has not been proven true.”
In a Climategate email in April of this year, Steve Colman, professor of Geological Science at the University of Minnesota Duluth, told scores of climate scientists “most people seem to accept that past history is the only way to assess what the climate can actually do (e.g., how fast it can change). However, I think that the fact that reconstructed history provides the only calibration or test of models (beyond verification of modern simulations) is under-appreciated.” (From a post by Terence Corcoran) In light of the Climategate emails, “under-appreciated” is probably one of the greatest understatements in scientific history. The foundation on which the climate models were built has suddenly turned to quicksand.
Can the evidence of anthropogenic global warming be any weaker? It is not evidence of a cause, but the evidence of absence, manufactured by computer models calibrated to questionable data.
Great post. It’s still “simple physics” — simple NON-LINEAR physics. And simple should never be confused with easy in physics. Nothing is as relative in physics as the word “simple.”
Jeffery D. Kooistra
Mathematically simple: If you remove CO2, at the beginning you remove money from peoples´wallets, then you remove people…
Great article Willis.
Let’s look at the climate over the last 350,000 years; the last three ice ages. It doesn’t follow the forcings.
It doesn’t match 3.0C per doubling, it doesn’t match the 100,000 year orbital cycle and it doesn’t match the high-latitude summer solar insolation Milankovitch Cycles either. It is mostly chaotic ice-albedo-feedback driving the climate.
http://img51.imageshack.us/img51/2127/last3iceages.png
http://img109.imageshack.us/img109/9195/milkanvsiceages.png
Instead of removing CO2 from the atmosphere it would be advisable to remove ideology from science.
Geoff Sherrington (03:02:33) : …and here we are dealing with earth´s nutrition and excretion process.
This is something that has bugged me a lot also. If it were a matter of just one equation, there would be no argument and no money spent on climate models. I tried to leave a comment on Lubos’ web site about this in response to someone who trotted out the Arrhenius equation for the 1000th time , but didn’t have a proper account.
Thermostat Effect ?
Knowledge it is neither esoteric nor hidden, it is out there for those who don´t reject it. Trouble is that ideology makes them “believe”, and behind passionate ideology there is some grade of psychological instability, to say the least, and consequently, biased perception of reality.
In the millions of years of man´s existence on earth can you imagine that a complete explanation of cosmos has not been achieved?.
Just cool it down and you will see the light! 🙂
This explanation of the complexity is exactly what I’ve been wishing for, thanks.
I enjoy the chaos pendulums on YouTube, one in particular that has “Synchronisation of 5 coupled metronomes done in Lancaster University” titled Synchronization.
These thought experiments above make me think of trying to synchronize hundreds of metronomes while the size of the soda cans underneath gradually changes, or attempting the same thing floating on water subject to random wave action.
Mike Borgelt (22:47:50) :
Leif Svalgaard (20:40:16) :
“Unfortunately, while the physics is simple, the climate is far from simple
That is because the Earth basically is cold without being too cold. Heat it up enough [say to 10,000 degrees] or cool it a couple hundred degrees, and simple physics takes over.”
Oh you mean like a star or the sun? Simple physics, totally predictable????
Mike: well, if there were no magnetic fields a star or the Sun would be nice and easy. My third year undergraduate students used to be able to produce decent models of quite realistic stars on an old BBC microcomputer in the 1980s; the global properties (ignoring magnetic fields) are not too difficult since the physics is not too complicated.
Introduce magnetic fields though and then you can get all sorts of complicated stuff, as we see with sunspots, flares, coronal loops, and so on. Another complex (and not too well understood) system; in the case of stars it’s the magnetic field that clobbers the simple models.
Great post, Willis.
Now we finally know what Willis was talkin’ ’bout.
Just sitting here in Houston, ready to start another relatively complex CFD (computational fludi dynamics) model (likely ~5 MM hexhedral cells, yikes) when I read this post.
Brilliant stuff.
Anybody can teach advanced concepts to highly qualified grad students (my materials prof, ex-Chalk River Nuke guy, who wrote on the blackboard (!) with his left hand, and in the next motion erased with his right, comes to mind)
I find that it takes the brighest minds to clearly explain complex concepts to the Rest Of Us.
OTOH I wouldn’t expect less from Science Blog of the Year.
This one gets forwarded to all the usual suspects.
This is one of the goofiest posts I’ve ever read on this topic.
First, the ‘author’ demonstrates how all solids are not alike in conducting heat (everyone who has had basic physics understands this). Then the ‘author’ goes on to show how humans (who are over 90% water and have active temperature adjustment mechanisms) don’t seem to follow the same principle. Doh!
Then he tries to confuse us about gravity and meandering streams. Erosion and deposition are indeed simple processes, but we are not supposed to think about them lest the ‘author’ fails to get his point across.
Based on these poorest of premises, the ‘author’ attempts a distant but failed leap at a conclusion that there is absolutely no way that the climate can be modeled in any shape or form.
Such is the fodder for little minds, but having both experience in physics and computer modeling, I find such a conclusion to be arm-waving at best, desperate denialism at worst.
[Reply: You are welcome to submit your own article explaining how well computer climate models work. ~dbstealey, mod.]