Sunday, November 1, 2009

A Saviour to the Rescue of Climate Change Models

The Toronto Star highlights a Bower award winner in Physics.

The sub-hed reads: "His insights into nature's diverse systems help prove the validity of climate change models." Wow, all those models used by the IPCC, increasingly under attack both for lacking robust data in the first place, and for failing to predict anything meaningful, are vindicated in one fell swoop by one big picture theorist.

Let's read on:

"THE WAY IN WHICH we try to prove to ourselves that the models have predictive capability ... is to apply the same models to epochs in the past," Peltier says.

"We take the same models which are being used to make future climate predictions and we ask `do they predict what we know to have been characteristic of the climate at this earlier time?'"

Make no mistake, Peltier says. For the sophisticated climate change skeptic, the models now used to predict future temperatures, glacial melting and rising ocean levels are global warming's Achilles' heel.

Based on scientific suppositions about past climates and the complex sun and earth conditions that caused them, they are too prone to error, too dependent on seas of suppositions to reliably forecast our future.

But this makes it sound like ... all those other models are wrong. All of them. Only Peltier has saved the day.

Amazingly, he has studied the geology of one precise period, in great detail, applied a mathematical model, and successively extrapolated his findings to other periods, presumably including our own. The article is frustratingly vague on some points:

Numbers and mathematical theorems are the tools of the theoretical physics that Peltier employs to communicate his disparate disciplines.

With them, Einstein could describe the potential power that lies within an atomic nucleus. Or with them, Peltier could pixelate a snapshot of a glacier's edge, 21,000 years ago, at the end of the last great ice age.

What was the solid earth doing at that time? How were the oceans behaving? What were the glaciers like just then, at the very end of their onslaught?

Providing precise answers to these questions has been the crowning achievement of Peltier's career so far, he says.

And it's those answers that are now used to prove that the monumentally complex computer models being used to predict future climate change are accurate.

Back to the beginning again. All of the models are accurate, even though on their own they have so far failed to predict anything?

To build his picture of the ice age world, where glaciers stood four kilometres high over much of what's now Canada and Europe, Peltier employed his own mathematical theorems and supercomputers to crunch millions of pieces of data.

That data included everything from ice core samples to satellite imagery of the ground rebounding still from its long-gone glacial loads.

And the picture Peltier painted with it was so precise and elegant that it become the proving ground for today's predictive climate change models.

"If the model doesn't pass the past climate test, then you should be very, very concerned about the future predictions you're making," he says.

Many of them have passed, and those successes, Peltier says, stand as the key rebuke to climate change skeptics. "The work that I do is exactly to counter these arguments that the models can't be trusted."

Many of them. Many of them have passed. Some, I guess, have not. Some may even be, dare I say it, elegant nonsense. But there are no details as to what has passed and what has not, what specific periods have been successfully predicted, or anything. What periods has Peltier himself studied, to show that his model from one specific time and place can be applied to other times and places, and fit actual data?

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