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Loading the Dice

Rolling snake eyes on the earth's delicate surface



Bill McGuire's book Waking the Giant: How a Changing Climate Triggers Earthquakes, Tsunamis, and Volcanoes is an edge-of-your-seat science tour and wake-up call.

McGuire, professor of geophysical and climate hazards at University College London, underscores the testimony of scientist Richard Alley to the House of Representatives in 2010, warning that a critical tipping point may be reached within 10 years and that "what is going on in the Arctic right now is the biggest and fastest thing nature has ever done."

Is fast so bad? Based on Earth's history and on emerging studies of surface reactions, McGuire's informed guess is yes.

We've been warned that ice melt leads to a rise in the level of the ocean, but McGuire's sobering data shows how ice melt also causes the redistribution of weight on the lithosphere, the rocky crust of the planet. The loss of ice weight on land causes a spring-back motion, comparable to a sofa cushion rising just after the person sitting there has gotten off the couch. This "post-glacial rebound," as scientists call it, has been historically linked to earthquakes up to magnitude 7. And earthquakes that trigger landslides, writes McGuire, in "a watery environment can produce tsunamis . . . destructive and lethal many thousands of kilometers from their source."

And then there are volcanoes. As all this weight is being shifted around and temperatures changing, those volcanoes already primed for a blast are sensitive "to even small changes in the environment." Yet even the nonprimed volcanoes can be triggered by weather events, through interrelationships and "feedback loops" quite complex and still under study.

Recent findings by volcanologists suggest that the weight of sustained rises in sea level redistributed from ice melt to the base of volcanoes creates enough pressure to potentially "promote expulsion of magma" or cause volcanic flanks to collapse. (Mount St. Helens exploded from flank collapse in 1981.)

Just as volcanic eruptions can be triggered by climate change, these eruptions in turn can contribute to further climate changes with gasses, heat and ash spewed from below. McGuire—with the caution characteristic of scientists and Brits alike—does not claim simple cause and effect but does assert that it would be "astonishing" if rapid climate change did not modify the "picture of global volcanic activity."

McGuire aligns himself with Alley's testimony to the (apparently deaf) Congress. We are, McGuire claims, "loading the dice in favor of increased geological mayhem at a time when we can most do without it." Our future outlook is grim, he warns, unless "there is a dramatic and completely unexpected turn around in the way in which the human race manages itself and the planet."

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