Tuesday, December 29, 2009

An unstable world

In 1915, an astronomer/meteorologist named Alfred Wegener suggested that the very ground people stood on was unstable. Whole continents had drifted over geologic time to their present-day positions but the map as we knew it was not always the map as we knew it. Though the idea made sense of a great deal of circumstantial data collected about past histories of the world, continental drift was a radical idea that many in the public and scientific community alike scoffed at. Wegener died before his ideas were catalyzed into the theory of Plate Tectonics and became widely accepted in scientific circles.

Why was the concept so radical and roundly criticized during his lifetime? One of many reasons was that it fundamentally challenged our understanding of the structure of the world around us. Continental drift started from the assumption that Earth's crust was dynamic and changing, not stable.

In many ways, the same sorts of critiques are being leveled at the concept of global warming. Among the so-called skeptics, there is a consistent incredulity that people have the capability to change something so large, so complicated, so fundamental as the atmosphere. How can people possibly alter something as vast as the atmosphere or the oceans?

Humans tend to have a problem with our ability to comprehend the abstract end to perceived abundance and understand that we play a role in changing the world around us. At one time, passenger pigeons were so abundant in the US that single flocks were estimated at a billion birds each. Audubon noted in 1813:

"…the light of noon-day was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow; and the continued buzz of wings had a tendency to lull my senses to repose.

Before sunset I reached Louisville, Kentucky. The pigeons passed in undiminished number, and continued to do so for three days in succession. The people were all in arms. The banks of the Ohio were crowded with men and boys, incessantly shooting at the pilgrims, which flew lower as they passed over the river. Multitudes were thus destroyed. For a week or more, the population fed on no flesh other that of pigeons, and talked of nothing but pigeons."

Similar stories can be told of American bison, boundless forests, and endless expanses of tallgrass prairie that was once a terrifying barrier. But the passenger pigeon is now extinct, the bison a novelty, forests fragmented, and tallgrass prairie confined to reserves. Is it so hard to imagine that people have fundamentally reshaped the world? It's what we do.

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