Tuesday, November 21, 2017

At Least Climate Change Doesn't Cause Earthquakes... Right?

Climate change doesn't cause hurricanes, but it can increase the frequency and ferocity of them.  Climate change doesn't cause droughts, but it can increase the severity and persistence of them.  Climate change doesn't cause earthquakes, either.
Or does it?
A geophysicist, Chris Milliner of NASA's JPL at CalTech, noted that when 53 inches of rain fell on Huston during hurricane Harvey, the town sank by 2 cm. Those 53" represented 33 trillion gallons of water.  Water weighs 8.34 lbs per gallon.  Do the math.  That's 137 billion, 610 million tons.  No wonder Houston sank.[1]
Okay, and then when the water receded, Houston rose back up again.  That's a good thing, right?  Well, it depends on how fault-ridden the bedrock under Houston is.  Turns out Houston is not a seismically active region, so there were no significant earthquakes detected.
A book by Bill McGuire titled Waking the Giant discusses the effects of climate change on the Earth's crust. [2] At the end of the last ice age, 20,000 years ago, kilometers thick sheets of ice covered much of North America and Europe, sea levels were 425 feet lower, and the average global temperature was 11°F cooler.  Then the rapid melting of ice caps and filling of ocean basins shifted the distribution of enormous weight on the crust of the Earth.  This caused earthquakes, volcanoes, underwater landslides, and tsunamis.  But not all of the glaciers melted and the global temperature stabilized.  Until humans discovered coal and the Industrial Age began.  We are now on track, with human-caused rapid global warming, to see these things resume.
California is a different story than Houston.  According to Warren Cornwall of Reuters, shifting water weight can trigger small earthquakes in California.[3]  During the driest time of year, late summer and early fall, the weight of water in California is minimal.  Then come the rains.  Reservoirs begin to fill.  Ground water is replenished.  And the weight of water on California's network of criss-crossing geologic faults increases.  This causes a pattern of increased frequency of earthquakes during certain times of year.
As the climate changes, oceans warm, storms pick up more water and become much more violent, and unprecedented volumes of water weigh down on California's faults.  Earthquakes are going to be the result.
As if that isn't a dire enough prediction, we may even see some new volcanoes![4]

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