Friday, April 3, 2009

Time is of the Essence

The models being used to predict and quantify the effects of environmental change fall short when it comes to understanding time, according to MacArthur award winner Alan Hastings, a professor of environmental science and policy at UC-Davis. He spoke Thursday at the French Family Science Center.

According to Hastings, time and space are essential to our understanding of ecological systems. However, “the classical approach to ecological models and theory ignores time scale issues,” he noted. “If we’re focusing on global change, we can’t ignore time scale issues.”

Another consideration is the relativity of time to living organisms. For instance, the last glaciation occurred 10,000 years ago. To a human, this represents a significant amount of time. However, to an organism such as a redwood tree, with a lifespan ranging from 500-2,000 years, that expanse of time is only a few generations.

Certainly, the earth works in mysterious ways. Hastings emphasized how even the most complex models cannot compensate for the natural complexity of ecosystems.

“Sudden changes may occur,” Hastings said. They don’t even have to be driven by external pressures. As a result, “complex behavior occurs even in very simple ecological models.”

The inherent unpredictability of earth processes can be frustrating. The key, Hastings said, is to know what can and cannot be predicted. Weather conditions for the next 1-5 days can be predicted with reasonable accuracy. However, any forecasting beyond that period becomes much more difficult. It’s just not possible to predict whether average rainfall or temperature for the next year will be above or below average, Hastings said.

Maybe we should cut the weatherman some slack.

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