Global Warming causes......

Earthquakes!

That's right, folks.  When the temperature of the air warms up a few degrees, the effect on geologic faults that lie 6 miles below the surface of the earth is immediate and severe.  The huge tectonic plates begin to cavort wildly, and presto! Severe earthquakes.

OK, this is obviously silly.

But the actual claim by the Global Warming Mongers is not much more valid.

In the wake of the horrific tragedy in Japan, the media weave into the reports of earthquake damage the claim that increased seismic activity is one of the threats posed by Climate Change.  This, of course, is  part of the strategy to 'never let a good crisis go to waste'.

They must advance to mantra of Global Warming, no matter how absurd or in poor taste. (Thousands are dead, but never mind that.  We must advance the cause!)

The theory is as follows:  Huge glaciers sit atop the land, and the immense weight of the ice is pressing down on the rock.  As warming causes the ice to melt, the weight is released, causing the land to rise.  This rise will then trigger increased activity along seismic fault lines, and we will have more earthquakes.

The Facts:  The glaciers do, in fact, push down on the bedrock with enormous weight, pushing the land down.  When the weight of the ice is released, the land does spring back to it's previous level.  It does this on a geologic time scale, ie, over tens of thousands of years.

One place where we see this is the Canadian Shield.  Having been compressed during the last ice age, it is in the process of rebounding, rising a few centimeters per year.  It has been doing this for some 10,000 years, since the time when mile-thick glaciers covered the northern hemishpere.

There is no evidence that this effect causes earthquakes.  And since the last ice age ended over 10,000 years ago, if the rebound effect did cause earthquakes it would be causing what we consider the 'normal' amount of earthquakes, as we do not have records during a time when the earth was not rebounding.

But none of this matters, because these minor changes in the level of the plates are NOT what causes major earthquakes. (We will only consider major earthquakes here, as minor ones are of no consequence to human life. There are thousands of tiny earthquakes everyday, and they are picked up only on the most sensitive instruments.)

Earthquakes are cause by plate tectonics. This is the process by which the major land masses float around on the molten surface of the earth's core, colliding with one another and causing vibrations in the crust as they ride atop one another, or slip past each other.  The plates move at rates of several centimeters a year. They get stuck in certain spots where stress builds up.  When something breaks, the plates snap forward to release the stress.

When the movement is large (measured in meters) we get large earthquakes.

This only applies when motion of the plate is opposed by another plate. There is nothing to stop the upward movement of the land as it rebounds from the weight of the glaciers, so they don't get 'stuck' when moving like this.

So the idea that global warming causes earthquakes is stupid and has no basis in science. It is an example of the vast over reach of the GW crowd.  They are so desperate to scare people into supporting their ideas, they are wildly overplaying their hand. 

The next time you hear something is caused by global warming, don't believe it.