Friday, May 1, 2009

A Simple Cloud

Physicist Freeman Dyson sounds reasonably skeptical about climate change, reported reasonably well in Scientific American:

"Too much of the science of climate change relies on computer models, he [Dyson] argued, and those models are crude mathematical approximations of the real world. After all, a simple cloud—small in scale, big in climate effects, the product of evaporation and condensation, all of which it is difficult to create equations for—eludes the most sophisticated climate models.

So climate modelers turn to what they call parameters or, as Dyson likes to call them: "fudge factors." These are approximations, such as the average cloudiness of a particular spot at a particular time, that are then applied globally. With the help of about 100 of these parameters, models can now closely match the world's present day climate, Dyson says. These models then, like the one developed at Princeton University where Dyson is a professor emeritus, are "useful for understanding climate but not for predicting climate."

That's too much of a temptation for scientists working on the problem, however. "If you live with models for 10 to 20 years, you start to believe in them," Dyson said."

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