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Somehow I find that thought uncomfortable that the complexity of factors impacting something as complex as climate is getting reduced to a wind tunnel test. On

by stfu 15y ago

Somehow I find that thought uncomfortable that the complexity of factors impacting something as complex as climate is getting reduced to a wind tunnel test. One is a highly controlled scenario where all(most all) the externalities can be controlled. The other some extremely complex modeling, which will, at least in my view, always depend on some consensus among the participants which factors are more important than others. I am far from a climate change skeptic, but the best example for the fundamental failure of grasping complex scenario with some factor-based prediction systems has been demonstrated with the complete failure of economics in predicting something as "simple" as the financial crisis. But then again, I am coming from a social science perspective assuming that as soon as humans are involved data and data analysis will always be subjective.

trevelyan 15y ago
You are not "far from a climate change skeptic". You are a climate change skeptic. At best, your post is the vague claim that complex systems cannot be modeled or tested empirically, and is empirically wrong in its claim that no-one predicted the financial crisis.
- ThomBot 15y ago
  Based on the second claim of stfu’s post, “as soon as humans are involved data and data analysis will always be subjective”, I think he is really trying to highlight the unpredictability of a model that must generalize human choices using statistics. Since even conservative scientists will agree that climate change has some anthropogenic dimension, we should understand the limitations of modeling it. Being skeptical of the model, however, does not prohibit you from accepting what the model is suggesting. Historical data and scientific opinion can be enough to convince us that climate change is occurring. But no model can predict how our reaction to that knowledge will affect climate change in the future.
- Produce 15y ago
  Call me a skeptic too in that case. Chaotic systems are inherently unpredictable to us, though they are ofcourse deterministic. The climate is chaotic (http://www.mendeley.com/research/nonlinearities-feedbacks-and-critical-thresholds-within-the-earths-climate-system/ http://www.mendeley.com/research/nonlinearities-feedbacks-an...). Chaotic systems have a horizon of predictability (http://www.britannica.com/EBchecked/media/3227/Sensitivity-of-a-chaotic-number-sequence-to-initial-value-illustrating http://www.britannica.com/EBchecked/media/3227/Sensitivity-o...), so climate models are still useful to an extent. They will tell us, with some degree of accuracy, roughly what will happen in the near future. The long term remains a mystery and there's little that can be done about that.
  - scarmig 15y ago
    It goes much too far to say that the climate is chaotic and therefore totally unpredictable in the long run. After all, if you buy that whole hog, you're also led to say that if you moved the Earth to Mercury's orbit it would be impossible to predict that the Earth would get hotter, in the long term. This results from the flaw of confusing weather (which is indeed chaotic) with statistics about weather (i.e. climate). A butterfly flapping its wings can cause a hurricane. But it can also prevent a hurricane. All those perturbations don't change the fact that, within an order of magnitude, we can predict how many hurricanes will occur in a given year. Alternatively, think about the classical three body problem: even though it's the preeminent example of a chaotic system, you can still make broad predictions about it. Center of mass, average speed of the bodies, average collision time. This isn't some obscure controversial field, either: in physics, these emergent statistical properties form the basis of statistical mechanics and therefore thermodynamics as a whole. Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system.
    - Produce 15y ago
      >Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system. But we can't tell what the weather will be in 45 days in New York. One of the attributes of chaotic systems is their self-similarity. The behavior on one level is similar to the behavior on another - in this case weather is similar to climate. We can make predictions about the weather in the next few days, just as we can with climate, but in the next few months or years (or centuries or millenia for climate) is another story. The tiny pertrubations in the system which we do not model (the butterflies) end up throwing our predictions off in the long run.
      - xyzzyz 15y ago
        Yes, and that's why nobody is claiming to be able to predict the weather in the long run. Nevertheless, some things still can be predicted, even in chaotic systems. What is your point?
Anon84 15y ago
Predicting the financial crisis is probably orders of magnitude more complex that climate change. Climate science is based on well known (although complex) systems of equations and laws that have been studied independently from each other for hundreds of year (heat diffusion, fluid flow, etc...). The tricky part is combining all the pieces is a system the size of the planet where a lot of quantities are still relatively unknown. Compare that with the financial crisis where there are no hard laws and the behavior of the system depends directly and inextrinsibly from how a large group of people scattered around the world will reach to certain hypothetical scenario in an unknown point in history. Will investor A be rational? Panic? How about B? What happens if B sees A panicking? Or vice versa? I'm not an economist, by can give you an example on epidemiology I worked on recently. Starting with one of the simplest epidemic models (SIR), as soon as you add a simple behavioral assumption (people can become afraid of the disease and behave more carefully) the behavior of the systems changes completely.
- eli_gottlieb 15y ago
  Predicting the financial crisis is probably orders of magnitude more complex that climate change. Orders of magnitude simpler, I'd think. "If real wages and household incomes keep dropping while household indebtedness keeps rising, you will eventually have a financial crisis." Marx never needed any math to work this out, just the good sense to realize that money never appears out of thin air.
  - Anon84 15y ago
    Don't mistake a bubble with a financial crisis.
  - deleted 15y ago
    [deleted]
  - neutronicus 15y ago
    There's as much content to that prediction as there is to the prediction "if you release carbon dioxide into the environment at an accelerated rate, the average temperature of the Earth will increase". What people are meaning by "prediction" here is something much more specific than what you mean and you know it.
astrec 15y ago
Complete failure of neoclassical economics, perhaps. There were plenty of people who predicted the GFC with varying degrees of accuracy; Steve Keen being but one.
- hesitz 15y ago
  The problem is that these people (and others) don't know enough to realize their economic predictions are worthless. There is truth to the old saw, "Economists are good at predicting recessions. They've predicted eight of the last three. . . " In many cases the prognosticators are fully aware that their predictions are worthless but persist in the facade to build up a reputation. It takes only a few lucky coincidences to get set up for life. People love to hear bold predictions.
khafra 15y ago
> One is a highly controlled scenario where all(most all) the externalities can be controlled. The other some extremely complex modeling, which will, at least in my view, always depend on some consensus among the participants which factors are more important than others. You do know that precisely modeling just a few seconds of turbulent flow would take more computer time than all the climate simulations in history, right? They're both approximations of intractably complex situations.
xixi77 15y ago
It will never be possible to credibly predict financial crises: if you learn that in a month your stocks are going to drop 50% you will try to sell them now. But, since other people have heard the same prediction, they will do the same, and the drop would happen today, rather than in a month. Such a prediction can only be possible if it's made by someone people do not believe. Which is, accidentally, completely in agreement with very classic economic theory. That being said, you are right in that climate models are woefully inadequate.
- eli_gottlieb 15y ago
  Predicting the precise moment of the "crisis", the pop, is semi-impossible due to markets being anti-inductive, yes. Spotting the structural, macroeconomic factors that will create a financial crisis is actually pretty easy.
jballanc 15y ago
The mathematics of economies falls in the field of evolutionary dynamics. This is a relatively young field, having its origins in the 1960-1970 time frame, and much of the fundamental principles are still being worked out. For one thing, evolutionary dynamics necessarily involves quite a bit of graph theory, much of which is difficult or impossible to describe with continuous functions. The mathematics of climate, on the other hand, falls in the field of statistical mechanics. While still a rather complicated field, statistical dynamics is much older, starting with Boltzmann in the late 19th century, and considerably more of the principles have been worked out. Statistical dynamics also deals more with continuous functions which, while not exactly easy to work with, can still be manipulated more easily than graphs.
roc 15y ago
Are you seriously arguing the analogy? As long as they are producing testable hypotheses and gathering new data to (in)validate their predictions, they are doing science. And if their theories make accurate predictions, it literally does not matter if those theories came from computer modelling, mathematical proofs, inspiration or divination. If we could make accurate predictions about the function of the universe by casting chicken bones, that would be science. Even though we wouldn't have the first clue what mechanisms might make it so. There's no shortage of such situations in science, where theories produce useful results despite no understanding of the underlying, clearly complex systems that drive them. e.g. The Placebo Effect, Gravity, etc. You seem to be arguing that every time science approaches a complex situation, which it doesn't understand and can't explain from first principles, that we cannot apply the Scientific Method. And that is patently false. That is exactly how we have come as far as we have. By creating falsifiable hypotheses, testing their predictions and refining those hypotheses. Your hand-waving doubts and fears about complexity and methods is fundamentally anti-science. You are not only a 'climate skeptic', you are apparently skeptical of man's ability to use science to investigate and understand the universe at all.

by stfu 15y ago

trevelyan 15y ago

You are not "far from a climate change skeptic". You are a climate change skeptic. At best, your post is the vague claim that complex systems cannot be modeled or tested empirically, and is empirically wrong in its claim that no-one predicted the financial crisis.

ThomBot 15y ago
Based on the second claim of stfu’s post, “as soon as humans are involved data and data analysis will always be subjective”, I think he is really trying to highlight the unpredictability of a model that must generalize human choices using statistics. Since even conservative scientists will agree that climate change has some anthropogenic dimension, we should understand the limitations of modeling it. Being skeptical of the model, however, does not prohibit you from accepting what the model is suggesting. Historical data and scientific opinion can be enough to convince us that climate change is occurring. But no model can predict how our reaction to that knowledge will affect climate change in the future.
Produce 15y ago
Call me a skeptic too in that case. Chaotic systems are inherently unpredictable to us, though they are ofcourse deterministic. The climate is chaotic (http://www.mendeley.com/research/nonlinearities-feedbacks-and-critical-thresholds-within-the-earths-climate-system/ http://www.mendeley.com/research/nonlinearities-feedbacks-an...). Chaotic systems have a horizon of predictability (http://www.britannica.com/EBchecked/media/3227/Sensitivity-of-a-chaotic-number-sequence-to-initial-value-illustrating http://www.britannica.com/EBchecked/media/3227/Sensitivity-o...), so climate models are still useful to an extent. They will tell us, with some degree of accuracy, roughly what will happen in the near future. The long term remains a mystery and there's little that can be done about that.
- scarmig 15y ago
  It goes much too far to say that the climate is chaotic and therefore totally unpredictable in the long run. After all, if you buy that whole hog, you're also led to say that if you moved the Earth to Mercury's orbit it would be impossible to predict that the Earth would get hotter, in the long term. This results from the flaw of confusing weather (which is indeed chaotic) with statistics about weather (i.e. climate). A butterfly flapping its wings can cause a hurricane. But it can also prevent a hurricane. All those perturbations don't change the fact that, within an order of magnitude, we can predict how many hurricanes will occur in a given year. Alternatively, think about the classical three body problem: even though it's the preeminent example of a chaotic system, you can still make broad predictions about it. Center of mass, average speed of the bodies, average collision time. This isn't some obscure controversial field, either: in physics, these emergent statistical properties form the basis of statistical mechanics and therefore thermodynamics as a whole. Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system.
  - Produce 15y ago
    >Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system. But we can't tell what the weather will be in 45 days in New York. One of the attributes of chaotic systems is their self-similarity. The behavior on one level is similar to the behavior on another - in this case weather is similar to climate. We can make predictions about the weather in the next few days, just as we can with climate, but in the next few months or years (or centuries or millenia for climate) is another story. The tiny pertrubations in the system which we do not model (the butterflies) end up throwing our predictions off in the long run.
    - xyzzyz 15y ago
      Yes, and that's why nobody is claiming to be able to predict the weather in the long run. Nevertheless, some things still can be predicted, even in chaotic systems. What is your point?

Anon84 15y ago

Predicting the financial crisis is probably orders of magnitude more complex that climate change. Climate science is based on well known (although complex) systems of equations and laws that have been studied independently from each other for hundreds of year (heat diffusion, fluid flow, etc...). The tricky part is combining all the pieces is a system the size of the planet where a lot of quantities are still relatively unknown. Compare that with the financial crisis where there are no hard laws and the behavior of the system depends directly and inextrinsibly from how a large group of people scattered around the world will reach to certain hypothetical scenario in an unknown point in history. Will investor A be rational? Panic? How about B? What happens if B sees A panicking? Or vice versa? I'm not an economist, by can give you an example on epidemiology I worked on recently. Starting with one of the simplest epidemic models (SIR), as soon as you add a simple behavioral assumption (people can become afraid of the disease and behave more carefully) the behavior of the systems changes completely.

eli_gottlieb 15y ago
Predicting the financial crisis is probably orders of magnitude more complex that climate change. Orders of magnitude simpler, I'd think. "If real wages and household incomes keep dropping while household indebtedness keeps rising, you will eventually have a financial crisis." Marx never needed any math to work this out, just the good sense to realize that money never appears out of thin air.
- Anon84 15y ago
  Don't mistake a bubble with a financial crisis.
- deleted 15y ago
  [deleted]
- neutronicus 15y ago
  There's as much content to that prediction as there is to the prediction "if you release carbon dioxide into the environment at an accelerated rate, the average temperature of the Earth will increase". What people are meaning by "prediction" here is something much more specific than what you mean and you know it.

astrec 15y ago

Complete failure of neoclassical economics, perhaps. There were plenty of people who predicted the GFC with varying degrees of accuracy; Steve Keen being but one.

hesitz 15y ago
The problem is that these people (and others) don't know enough to realize their economic predictions are worthless. There is truth to the old saw, "Economists are good at predicting recessions. They've predicted eight of the last three. . . " In many cases the prognosticators are fully aware that their predictions are worthless but persist in the facade to build up a reputation. It takes only a few lucky coincidences to get set up for life. People love to hear bold predictions.

khafra 15y ago

> One is a highly controlled scenario where all(most all) the externalities can be controlled. The other some extremely complex modeling, which will, at least in my view, always depend on some consensus among the participants which factors are more important than others. You do know that precisely modeling just a few seconds of turbulent flow would take more computer time than all the climate simulations in history, right? They're both approximations of intractably complex situations.

xixi77 15y ago

It will never be possible to credibly predict financial crises: if you learn that in a month your stocks are going to drop 50% you will try to sell them now. But, since other people have heard the same prediction, they will do the same, and the drop would happen today, rather than in a month. Such a prediction can only be possible if it's made by someone people do not believe. Which is, accidentally, completely in agreement with very classic economic theory. That being said, you are right in that climate models are woefully inadequate.

eli_gottlieb 15y ago
Predicting the precise moment of the "crisis", the pop, is semi-impossible due to markets being anti-inductive, yes. Spotting the structural, macroeconomic factors that will create a financial crisis is actually pretty easy.

jballanc 15y ago

The mathematics of economies falls in the field of evolutionary dynamics. This is a relatively young field, having its origins in the 1960-1970 time frame, and much of the fundamental principles are still being worked out. For one thing, evolutionary dynamics necessarily involves quite a bit of graph theory, much of which is difficult or impossible to describe with continuous functions. The mathematics of climate, on the other hand, falls in the field of statistical mechanics. While still a rather complicated field, statistical dynamics is much older, starting with Boltzmann in the late 19th century, and considerably more of the principles have been worked out. Statistical dynamics also deals more with continuous functions which, while not exactly easy to work with, can still be manipulated more easily than graphs.

roc 15y ago

Are you seriously arguing the analogy? As long as they are producing testable hypotheses and gathering new data to (in)validate their predictions, they are doing science. And if their theories make accurate predictions, it literally does not matter if those theories came from computer modelling, mathematical proofs, inspiration or divination. If we could make accurate predictions about the function of the universe by casting chicken bones, that would be science. Even though we wouldn't have the first clue what mechanisms might make it so. There's no shortage of such situations in science, where theories produce useful results despite no understanding of the underlying, clearly complex systems that drive them. e.g. The Placebo Effect, Gravity, etc. You seem to be arguing that every time science approaches a complex situation, which it doesn't understand and can't explain from first principles, that we cannot apply the Scientific Method. And that is patently false. That is exactly how we have come as far as we have. By creating falsifiable hypotheses, testing their predictions and refining those hypotheses. Your hand-waving doubts and fears about complexity and methods is fundamentally anti-science. You are not only a 'climate skeptic', you are apparently skeptical of man's ability to use science to investigate and understand the universe at all.