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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Mr. Eschenbach, you’re being too kind. Many of those mistakes, too many, you can do ten times or more before you teach yourself to automatically check for them. It actually gets harder near the end of the list, since as you become more aware of the mistakes you can do, you realize how many times you did the end ones without even realizing it.
Keith Minto (14:37:42), you point out an interesting distinction:
Keith, what Bejan said does not mean that the flow follows the “path of least resistance”. This is because the flows are not all in the channel.
Consider a river as an example. In addition to the flow in the channel, there is a large and unceasing flow to and from the subterranean water table surrounding the river, as well as surface flows over the same area.
So as always, things are more complex than they seem. The system is evolving to maximize the flow to/from the water table/surrounding land, while at the same time evolving to maximize the flow from the top of the hill to the ocean. This “double maximization”, where the system is not maximizing one variable (e.g. “least resistance”) but two, is a distinguishing characteristic of the constructal analysis.
w.
kadaka (15:16:28) : edit
I agree wholeheartedly. You see these white hairs on my head? …
OK, maybe I’m feeding the troll but, assuming he has packed up and moved along, I did want to point out the chutzpah in his last post:
“They call themselves skeptics, which implies having an open mind, but on the contrary, their minds are completely shut down.”
He says this after saying of this link, “Um, no, it’s not from models, it’s from actual data.” But, the site explicitly says it is: “using best-known corrections to systematic errors”. Where did those corrections come from, if not a model? He should call himself “ObtuseBeing”. I don’t know about the rest of you, but the single word “corrections” has become enough to convince me that the data I am about to view was very likely pulled from some dank orifice somewhere.
Then, he completely ignores the contradictory direct evidence from Smokey (12:07:57) culled from the same site. And, then he takes his ball and goes home (yay!).
I’ve come across the troll named Ed Darrell elsewhere, too. I am convinced he is not a real person, but a random phrase generator.
“…data I am about to view were very likely…”
I rewrote the sentence several times to get in in a form I liked, the subject and verb agreed in the penultimate case, and I missed it in the last scrub. Just don’t want some troll suggesting my seeming lack of command of the English language is evidence of overall intellectual deficiency.
Willis Eschenbach (19:59:09)
Your earlier reply to MrAce:
“Because of the slow changes of the Milankovich cycles. These change the insolation in an odd way, that seems to lead to a bi-stable state of glaciation and interglacials…
This implies a thermostat mechanism of some kind. … It may not be the mechanism I postulate, but if not, what is your alternate explanation?”
Your own article answers this question. In describing the Constructal law you state that: “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 achieve.” As I’m sure you are aware, the preferential state you refer to is known as an “attractor” or sometimes “strange attractor” in the study of non-equilibrium pattern formation at the boundary of chaos. Why strange? Because the system is attracted to a certain small region of the phase space of the system without there being any obvious reason why. A system can have more than one strange attractor. Sometimes the metaphor of landscape is used to describe attractors, a landscape of mountains, ridges and valleys, with height representing the inverse of probability or improbability (a.k.a. Richard Dawkins’ “climbing mount improbable”) so that peaks are the least probable states and valleys the most probable states. Major valleys are the attractors according to this analogy. The phase space of a system (multidimensional set of all possible states) can have several attractors. However if these valleys are separated by high mountains or ridges, movement from one valley to another is difficult. But such a transition can be facilitated by a high “mountain pass” or what is geometrically called a saddle.
Once one gets a feel for these systems it becomes of course obvious that, in the earth’s climate, the glacial and integlacial states are strange attractors. As you point out, cyclically varying perturbations such as Milankovitch cycles, and other possible influences such as solar and oceanic cyclical phenomena, periodically push the system from one valley to the other. This situation pertains while the earth is in a glacial phase, which of course has been only for a fraction of its history. Tectonic movement placing a lot of land surface near one or both poles seems to tip the climate into sometimes a continuous ice age of tens of millions of years (single dominant attractor) or as in the present time a bistable state flipping between glacial and interglacial (two attractors with an accessible route from one to the other).
Once one is attuned to the nature of such system you can recognise them everywhere in the natural world. It then becomes frustrating that others cant see what is happening. A good book for a general and very accessible introduction to such systems is “Deep Simplicity” by John Gribben, Random House, NY.
The recognition of non-equilibrium pattern formation at the boundary of chaos has the potential to give new insight to many scientific disciplines where systems are highly complex, notably biology. However scientific research has historically focused on systems that are of an equilibrium nature and “linear”, perhaps simply because the familiar tools of mathematical analysis give more fruitful results in such systems (ironically the exceptional linear, equilibrium systems have acted as chaotic “attractors” for scientists).
But the response of science to the real world reality of non-linear non-equlilbrium pattern dynamics, with its associated unfamiliar phenomena of attractors, limit cycles etc, should not be to (a) ignore them and look for something else to study, or (b) try pointlessly to study them with linear equilibrium type analytical tools, but to start to develop a new set of analytical tools and approaches based on the actual extent to which such systems can be analysed or at least informatively observed.
A river is always a bit tricky to use as a role-playing model because it is itself so powerful:
The river-earth boundary both guides the flow (as the banks restrict the river to the previous path) but the flowing water carves and gouges only one side of the bank.
The water flow scoops away dirt and mud “easily” on the outside of a curve (looking downriver) but deposits it on the slower inside part of the curve downstream a little (but variable) distance. Change the water flow with an upstream snow melt, large storm or flood from a tributary, and the downstream stretches of the river change yet again.
But this formula is itself too simple: Add a higher hill on side, and the bank won’t erode. Put a rock formation or upthrust fault across the path, and it will either cut through the weaker rock keeping the same notch at the same location as the land rises over millions of years, or flow around it for thousands of years.
For these reasons, I prefer your “pour water down a flat plate” comparison better. Good job, and thank you.
…—…
More generally,
Wanting to control Western civilization and – more important in the short term – western economic growth and money, and the liberal/environmental/socialist/hate-capitalism movement cannot afford the time to study or understand the “randomness” and subtle causes affecting the climate.
They “need” – immediately and urgently to impose their “solution” (tax carbon and send the money to the UN) because they have sold themselves on that “faith” … But they have never had the “science” behind them, and cannot afford to let any one else have the time or podium to tell the truth.
They cannot afford to let others (skeptics and realists of any degree) speak freely, because the imperial “consensus” is their strength. Well, that and a docile, muzzled, subservient, liberal mainstream press “corpse.”
Willis,
Maybe this will work on those two guys: click
ThinkingBeing,
On my 3rd repetition, we can only come to the conclusion that you are avoiding the question because you, like the IPCC and the rest of the world’s alarmists, are unable to answer it:
“Exactly what is the evidence that man’s CO2 is causing global warming ?
Please also give a page number reference to the latest IPCC report where this evidence is presented.”
No evidence means AGW is fools’, scammers’ and politicians nonsense. Which category are you ThinkingBeing ?
Everyone else, if he is unable to decipher the message above, DO NOT FEED THE TROLL. Let him blather on, but do not answer him. Let him wallow in his own idiocy, but please don’t reply to him.
Yeah, for me it’s almost always “one and out” when it comes to trolls, unless they really just perfectly T one up later. Anything longer than a one-liner isn’t worth it though it’s sometimes hard to restrain and resist.
MikeF (09:44:14) :
“Let’s do simple thought experiment. Assume that you want to make river’s life easier by taking some of it’s resistance out. Let’s cut a bypass through one of the existing loops. This should be less “resistive” to the river then going the long way, agree? Not only would it make river shorter, you would line the new canal with nice slippery concrete so it flows easier. Well, as it turns out, the river will create extra loop elsewhere and maintain its length. It looks like it is not “interested” in least resistance as much as in maintaining its “status quo”.”
At one time, I owned a rural property that had a meandering stream running through it. To all appearances, the course of the stream was stable, and had been for some time. At one point, the banks had been lowered and rocks placed in the stream to create a ford. The tracks to and from the ford ran on both sides of the stream.
We replaced the ford with a small bridge that had concrete abutments, but otherwise made no other changes.
Within weeks of finishing the bridge, part of the bank, upstream of the bridge started to subside, so we planted a Willow to stabilize it. That worked, except that the opposite bank started to subside, not only upstream of the bridge, but also downstream. We planted two more Willows, and then several more, … you get the picture.
Finally, the course of the stream shifted significantly in a heavy rain storm, and we were left with a bridge to nowhere, and a whole lot of stranded willows.
There is a message here: don’t mess with nature unless you are absolutely sure that it’s broke.
Willis,
Just a few general thoughts on Constructal Law.
In trying to understand GW, we all come from different disciplines. I come from a biological background and can see and reason with your argument about climate ‘complexity’.
Adrian Bejan is a mechanical engineer was using designs from nature (trees, lungs) to formulate CL primarily for efficient cooling system designs for microprocessors.
Where we each come from in our training does not matter,it is how far we travel but it does color our view of the workings of the climate system. I am a bit of a Lovelockian in that I see the land/sea biota as a regulating factor in climate stability. Bejan sees a flow system as one that aims for low resistance and builds nature into his Law.
Quote….”The effort to improve the performance of an entire system rests on the ability to minimise all internal flow resistances…….. and maximise system performance”…… this leads to “entropy generation is spread optimally”.
Possibly this is correct but as this is not the place to discuss this at length, I see as a biologist, problems discussing tree shape,lungs and elephants ears in terms of resistance minimisation efficiency only.
Bejan , a mech. engineer, with heat sinks in mind, sweeps designs from nature into his Constructal Law and fails to see biological complexity that (to me) encompasses much more than resistance minimisation.
Then again, I lack knowledge of physical engineering.
Very thoughtful topic, Willis.
Willis Eschenbach (00:40:49) :
Nui mana
Maori: Much respect
Keith Minto (20:06:58)
Excellent issues, Keith. The Constructal Law (CL) has had great success at deriving ab initio a variety of formulas for things in nature that were previously only known as practical heuristic formulas. These include such things as the relationship between metabolic rate and body size.
You are correct that such things as “tree shape,lungs and elephants ears” cannot be analyzed using resistance minimization.
However, it is not correct to say that CL involves “resistance minimization”. As I mentioned above, constructal calculations generally involve a double maximization (or minimization). It is not simply minimizing resistance, or maximizing entropy, or the like.
Instead, as I mentioned above, it generally involves a double maximization (minimization) of two separate variables. Mathematically solving for both of these simultaneously yields deep insights into the natural phenomena, including the solution of previously unsolvable problems.
Regards,
w.
Rereke Whakaaro (20:43:40) : edit
As someone who has spent a good chunk of his life living on small South Pacific islands, I can only say “Nui mana” in return.
w.
An excellent essay sets one thinking. Would you allow another example to the two you gave at the start? It’s simple.
Why does the surface atmospheric pressure, being the weight of air above a point, vary? Why has it not settled to give a global equilibrium at each point?
(If it was not for geometry, there would be no point in Life).
Willis Eschenbach (03:16:54) :
A meandering stream would yes, not have a simple path stream. It is meandering because it doesn’t have the force to cut through an obstical in its path. It is making a path of least resistances. It is just wandering, looking for your equilibrium. But weather and climate does not work that way (except maybe occasionally at the equator).
I understand the concept, and it may work in a lab setting. But I can’t see how it can be used to show climate and weather changes regarding our earth. The fact is, we can not do anything to forecast the climate right now because we are doing it with a preset thought.
Anyway, kudos to you for looking for an answer.
Willis Eschenbach (03:16:54) :
Oh, and one more thing regarding the meandering river…..plate tectonics.
Well, I am sorry for troll-feeding, but some outrageous statements need at least a temporary engagement in order to set the record straight for others reading. And personally, I love ARGO. Never before did the alarmists shoot their own theory down so effectively… and no whitewash is more obvious once you point it out to someone.
Seems to me, as others have pointed out, we ought to be RELIEVED there is no cAGW… instead “we” hide the evidence.
Willis, now the troll has gone, could you please address my comment of yesterday (08:13:51) in which I reflect on your central thesis that:
“Because climate is a flow system far from equilibrium… there is no ‘physics-based’ reason to assume that increasing CO2 will make any difference to the global temperature, and … the ‘simple physics’ relationship between CO2 and global temperature is something that we cannot simply assume to be true.”
Yes right, but it is actually the physics that tells us this as much as complexity theory. In far-from-equilibrium states it is often something simple and physical that finally triggers a bifurcation. e.g. increased flow rate will cause the river to burst its banks, or extra snow on a slope will trigger an avalanche. No matter how complex the system, surely it can be something simple and physical that causes catastrophic change into a new attractor. Yes, there is massive underlying complexity that needs to be understood, but surely the trigger, when it comes, is sometimes down to ‘simple physics’. Of course most of the time the parameters will be within normal tolerances and the river will happily meander, the snow slope will allow happy skiing, and the climate will oscillate in its natural cycles. It is on, or near, the edge of chaos that things get difficult – the river busts its banks, the slope avalanches, the climate lurches into an ice age or warming phase.
I don’t at all believe that CO2 is a trigger, but there is at least no theoretical reason why it shouldn’t be, at the edge of chaos. I am probably not using the terms correctly, but our arguments must be based on sound theoretical foundations.
Willis,
[quote]The earth has seen some astounding changes in forcings. Meteor strikes, millennium long volcanic eruptions, changes in ocean chemistry, huge forest fires, and a 25% increase in solar energy have not changed the temperature by more than a few percent. How do you explain this without some kind of thermostatic mechanism? And since the Constructal Law says that every flow system has such a mechanism, that every flow system actively tends towards a preferred state, why should we assume that the climate is somehow unique and different?[/quote]
Yet the climate *has* changed, and has remained changed at higher or lower temperatures than now for periods of up to hundreds of millions of years in the past. All that is being argued for now is a meagre 1.5-4.5C in 100 years or so which is well within what has repeatedly happened in the past.
Yes there is some sort of thermostat. For example, evidence would suggest that high temperatures reduce levels of CO2 in the atmosphere by more rapid rock weathering (CO2 forms carbonic acid in rain which reacts with rocks forming insoluble carbonates which are eventually deposited at the bottom of oceans). Low temperatures allow CO2 to build up through slower rock weathering – including because the rocks are encased in ice and it is too cold for rain that would wash the CO2 out into the rocks. This process won’t work fast enough to prevent AGW.
I won’t be surprised if constructal law tells us interesting things about the earth’s thermodynamics. I don’t think it will tell us that the earth cannot be warmer or cooler than now any more than I expect it to tell us that mammals larger than an elephant or smaller than a shrew cannot exist due to constraints on their design.
I am a hydrologist, and find your examples oversimplified to the point of being useless, especially the meandering of rivers–if the water flowed on plywood (or in concrete channels) and did not carry sediment, they would not form meanders and the forms typical of an alluvial valley. The water, by the way, continues to flow downgradient. “Downhill” is a loose term that has little meaning (especially if ground water is under discussion).
Actually, “simple physics” is adequate. The difficulty is in recognizing how many “simple physics” terms need to be included, and gathering adequate data on each of the terms. A model can adequately explain a complex system to the degree necessary to understand it and, if appropriate, to recommend action to take. Furthermore, a model can be refined as additional data are obtained–an excellent example is seen in the use of climate models, which have gone well beyond inputting concentrations of carbon dioxide and outputting global temperature. Other terms are input, and the models have been refined as more data and greater understanding have become available.
Mark Duigon (07:04:56) : Your perspective is valid, however, the climate models do not work. The modelers insist on incorporating terms for things like forcing for CO2 that are too high, and have no observational/empirical basis. You can refine all day, but if your basic assumptions are wrong, the model will never work.
Mark Dugion- When you say “actually ‘simple physics’ is adequate” I assume you also acknowledge that there is such a thing as the three body (or n-body) problem which makes extreme computational demands on any realistic projection of climate into the future. My understanding is that; yes, “a model can adequately explain a complex system to the degree necessary” – provided you have enough computational power. To me the question becomes how much power is that? Hadley already has at it’s disposal one of the biggest and fastest supercomputers available. I suspect they acknowledge they would like and need even more power.
My understanding of climate models is that they work great matching existing data as long as the modelers are given enough parameter space. Parameters which may not have any basis in reality.
“Give me four parameters, and I can fit an elephant. Give me five, and I can wiggle its trunk” – John von Neumann
Robin (02:54:16)
Without the troll the air is cleaner, the sky is bluer, and it’s new years eve. Let’s get to it.
You are talking about a system in a state of what is sometimes called “self-organized criticality”. A well-studied example is a pile of sand to which we add a grain of sand at a time. At some point, we add “the straw that broke the camel’s back”, and a landslide (sandslide?) occurs.
While it is clearly “simple physics” that triggers the actual slide, predicting in advance which grain of sand will be the one to cause the next slide is far from simple physics.
The whole argument about “tipping points” is common. And while it is true that something tips the earth into and out of ice ages and into and out of Dansgaard-Oeschger events, we have a very hard time determining what that is even in retrospect. And at present we have no hope of doing it prospectively. Why? Because it is as far from “simple physics” as you can get. The difficulty is that every grain of sand is just about identical … so which one will cause the tipping point?
w.