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The Unbearable Complexity of Climate

38 points| azgolfer | 16 years ago |wattsupwiththat.com | reply

36 comments

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[+] Retric|16 years ago|reply
Saying, "I don't understand what's going on" does not mean that nobody understands what's going on.

PS: If you actually carried out the experiment using the picture as a guide you would measure a rise in body temperature. The human body trys to maintain constant temperature, but it can't ignore the laws of physics.

[+] petewarden|16 years ago|reply
Amen. This is a long opinion piece, with no evidence cited that the Constructal Law is a better predictor of the climate's response to increased CO2 than existing techniques. The one relevant paper linked to is an intriguing but underdeveloped model:

http://homepage.mac.com/williseschenbach/.Public/Constructal...

The paper doesn't back up the author's claim that "there is no physics-based reason to assume that increasing CO2 will make any difference to the global temperature". It includes an assumed factor y=0.4 for the infrared reflectance 'greenhouse factor', and any increase in that value will affect the expected results.

If anything applying the Constructal Law would be more worrying than current models, since there's potentially a more chaotic response to increased CO2 levels, increasing the risk of dramatic climate changes.

[+] jcnnghm|16 years ago|reply
"does not mean that nobody understands what's going on."

What are all the inputs and outputs? Which are significant? Does anybody know the answer to either of these questions? You can build a model without knowing all the inputs and outputs, but it's called a guess.

[+] Tichy|16 years ago|reply
"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 any difference to the global temperature, and the Constructal Law gives us reason to think that it may make no difference at all."

Sorry, but that is stupid. Just because changing one thing (ie making a short cut in the river) doesn't change one other thing doesn't imply that no matter what you change, nothing will change. Also, the author never seems to have seen a redirected river in a bed of concrete.

It's been nice to have learned about the constructional law, but other than that, I have to take this article with a grain of salt. It clearly doesn't seem to be neutral in motivation.

[+] andrewcooke|16 years ago|reply
is this kosher?

it starts out fine, explaining how complex systems are, well, complex. but then it starts to seem a bit odd because it ignores statistical properties (you can't predict the movement of every gas molecule in a box, but you can know the average temperature pretty damn accurately). and then suddenly it jumps to "constructal law":

> The Constructal Law applies to all flow systems which are far from equilibrium, like a river or the climate.

wtf? how can something as vague as "the climate" follow a law? and what's the constructal law? and so you go to wikipedia - http://en.wikipedia.org/wiki/Constructal_theory - and it all starts to look a bit flakey...

[edit: less flippant]

[+] DaniFong|16 years ago|reply
Heh.

The human body is a 'flow system far from equilibrium.' So while it's true that if you dunk the feet of a healthy person in hot water and wait, the temperature of their forehead may not increase by that much, it does not imply that the temperature of their feet won't increase, it does not imply that the forehead temperature of a hypothermic person won't increase, and it does not imply that the forehead temperature of a healthy person exposed to a flamethrower will not increase...

Does the Constructal law say anything about the environment were the Sun to suddenly disappear?

[+] vannevar|16 years ago|reply
I wonder if Mr Eschenbach realizes that the effectiveness of America's entire nuclear arsenal relies on the computer models he so casually dismisses. Nuclear weapons testing is virtual, and has been since 1992.

Contrary to the article, climate models don't assume a relationship between CO2 and global warming; rather, they reflect what we know about the physical properties of CO2 in the atmosphere, as born out in laboratory experiments and field measurements. The relationship with global warming emerges from the models, not the other way around.