Whatever…

Chaos

I noticed that Edward Lorenz died the other day. He was a meteorologist. He was not a summer visitor, he did not enjoy quahoging in Antier’s Pond or walking at Squibnocket. He was not a longtime member of the Barnacle Club. He was the guy who originated and helped develop chaos theory. It has nothing to do with the homely tensions among parents and children that all of us experience as chaos. It has a lot to do with things like weather forecasting, and maybe even end of the world, global warming theory.

Lorenz is known for the “butterfly effect.” Unlike the practice by the same name that was popularized a few years ago in the TV series L.A.Law, Lorenz’s idea was that, meteorologically speaking, a tiny waggling, like the flap of a butterfly’s wings might have enormous consequences, planet-wise, for the weather.

He had written some computer modeling programs that were to simulate the ingredients of weather. The goal was to develop a way to confidently predict what tomorrow, or a week from tomorrow, might be like. He ran the program one day, then decided to let it continue its run. So, he input some output developed earlier in the simulation, As the NYT explains it, “The computer program was the same, so the weather patterns of the second run should have exactly followed those of the first. Instead, the two weather trajectories quickly diverged on completely separate paths.”

Lorenz did what all of us do. He blamed it on the computer, or the office computer geek. But, he realized that the numbers he had inserted, numbers produced by the first simulation, had been rounded in the machine’s printed output from six decimal places to three. Inserting the rounded numbers, dropping three decimal places - whatever the three are after tens, hundreds, thousands - a discrepancy of less than one tenth of a percent changed the model’s weather. He concluded ultimately that perfect weather prediction is a fantasy. A sub-fractional “twiddling” (the NYT’s word) of the numbers in such a computer model could make big changes, so, what might have been expected to be a series of weather events that ought to have replicated themselves became chaotic and random.

Of course, the key here is that it was the computer model’s output that was chaotic. It wasn’t the weather itself. The weather was doing what it does, unpredictably.