Models Methods Software

Dan Hughes

This looks Interesting

I just ran across info about this new book over at Prometheus;

Useless Arithmetic
Why Environmental Scientists Can’t Predict the Future
BY: Orrin H. Pilkey and Linda Pilkey-Jarvis
Columbia University Press, New York, 2007.

The main Web page

An excerpt

Near the bottom of the excerpt the authors say, “Without resorting to mathematics, we make our point that applied quantitative mathematical models of earth processes cannot produce accurate answers.”

One reviewer blurb says;

“Orrin H. Pilkey and Linda Pilkey-Jarvis argue that many models are worse than useless, providing a false sense of security and an unwarranted confidence in our scientific expertise. Regardless of how one responds to their views, they can’t be ignored. A must-read for anyone seriously interested in the role of models in contemporary science and policy.”
—Naomi Oreskes, professor, Department of History, University of California, San Diego

All this is somewhat depressing.

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February 20, 2007 - Posted by | Uncategorized |

7 Comments »

  1. Is there a computer model of a complex system, in any field of study, that does not diverge from reality as time progresses in the model?

    I constantly ask scientists and informed people this question. To date nobody has shown me an example of such a model. Any readers know of such a model?

    Comment by Reid | February 21, 2007 | Reply

  2. re: #1. My personal experience is limited to applications for which a week would be the general range of the longest time span. And the boundary conditions were well-known and correctly specified for the calculations. The physical phenomena and processes are definitely inherently complex; multi-scale, multi-phase transient flows of compressible fluids in the very complex geometry of engineering equipment. Validation of the calculations by comparisons with experimental data were also very successful.

    The time range for my experiences pale in comparison to those that are encountered in say climate change. I think knowing the boundary conditions and the evolution over decades of very important processes that are not fully modeled in these analyses are among the important unresolved issues.

    I continue to hold an optimistic and deterministic outlook on all modeling endeavors.

    I quess we might need to narrow the field relative to examples of models validated over extensive ranges of time. Certainly the motions of the planets. for example, can be accurately calculated for millions of years. Do you have specific application areas in mind.

    Comment by Dan Hughes | February 21, 2007 | Reply

  3. Re #2:

    I’m not sure the motion of the planets would be considered a complex system. Celestial mechanics consists of a small set of elegant equations. I wouldn’t trust planetary motion calculations for millions of years. Gravitational forcings external to the solar system may introduce significant perturbations that can’t be predicted.

    I believe the current state of mathematics and computer science is too immature to accurately model complex systems beyond a short initial period. A good analogy is how Einstein’s theory of general relativity fell into place once he was introduced to elliptic geometry by his friend Marcel Grossman. There is a yet to be discovered mathematics beyond the stacks of partial differential equations that are used in GCM’s. If and when the new math is discovered it may yield accurate complex models.

    Comment by Reid | February 21, 2007 | Reply

  4. Why depressing? The only thing that is depressing is that climate models are taken seriously at all.

    A couple of days ago on the BBC (the fount of climate alarmism in the UK) came this report:

    Wind shifts devastate ocean life
    By Jonathan Fildes
    Science and technology reporter, BBC News, San Francisco

    The delicate interplay between the oceans and atmosphere is changing with catastrophic consequences.

    Entire marine ecosystems have been wiped out, devastating populations of sea birds and larger marine mammals.

    These “dead zones” occur where there are disturbances to the nutrient-rich ocean currents, which are driven by coastal winds.

    Extreme marine suffocations have occurred off the west coast of the US every year for the last five years.

    The most intense event, which left the ocean floor littered with the carcasses of crabs, happened in 2006.

    Right at the bottom of this came this incredible statement:

    In the meantime, they say, we must change our approach to managing and using these ecosystems, particularly for fish stocks.

    “The most prudent course of action is to begin to think differently about what is happening,” said Dr Lubchenco.

    “Climate models predict increasing uncertainty with wild fluctuations. We should expect more surprises.

    As Jon Stewart would say: “Waaaaaah?”

    Climate models appear to be capable of predicting anything, even “increasing uncertainty with wild fluctuations”. Its time that climate models started to justify their existence rather than as an intelectual battering ram to all rational conversations about climate.

    Back to you, Dan.

    Comment by John A | February 21, 2007 | Reply

  5. re: #3. “Celestial mechanics consists of a small set of elegant equations.” But accurate numerical integration over enormous time scales is an extremely difficult problem. Special-purpose computers have been built to do the job.

    Otherwise, Reid, you’re on a whole nother plane than I am.

    Comment by Dan Hughes | February 21, 2007 | Reply

  6. re: #3 ps, Reid I asked, “Do you have specific application areas in mind.” I guess you do not. We could look for applications if you’ll give us a hint.

    Comment by Dan Hughes | February 22, 2007 | Reply

  7. Re #6:

    I have no particular application areas in mind. I am not a scientist but do have BS in Physics. When I studied physics and computer science in the 1980’s on the undergraduate level I learned about the limits of computer modeling and numerical computation. Hence I have been stunned by what I see as blatant misrepresentation of GCM capabilities by both scientists, politicians, the media and the environmental community.

    I have followed your comments on Climate Audit and other blogs and found them to be right on the money. A few months ago you posted on Climate Audit a litany of problems with the AOLGCM’s. That post should be required reading for all scientists who think who multi-decadal climate have real-world predictive value.

    To sum up where I’m coming from, I believe climate science has been corrupted by big government money and now should more accurately be called Political Climate Science.

    Comment by Reid | February 22, 2007 | Reply


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