Did you know that the volcano that exploded in Iceland was most likely because of global warming? I didn’t either, but an expert says it is “just the beginning“:

Hooper [“an expert on Iceland’s volcanoes at Delft University in Holland”] warned that the eruption may be only a taste of the future if climate change causes ice sheets to melt further. As the last ice age ended, volcanic activity in Iceland increased 30-fold because of reduced pressure on the earth’s mantle.
“Since the 19th century the ice caps in Iceland have been shrinking yet further,” said Hooper. “This will lead to additional magma generation, so we should expect more frequent voluminous eruptions in the future.”

So there you go. The global warming mechanism thingie takes the ice caps off the earth’s surface, which makes it lighter, and more likely to explode!
Poof!
The theory is explained in more detail here, although the scientists caution that AGW might not have causes Eyjafjallajokull to erupt. The point is, it should be a warning!

Eyjafjallajokull, although the 5th largest glacier in Iceland, is considered too small and light to affect local geology. This does not detract from research done by Freysteinn Sigmundsson, a vulcanologist at the University of Iceland, who confirms that “eventually there will be either somewhat larger eruptions or more frequent eruptions in Iceland in coming decades.”
He said that global warming melts ice and this can influence magmatic systems pointing out that the end of the Ice Age 10,000 years ago coincided with a surge in volcanic activity in Iceland. This apparently as a result of the land rising while huge ice caps thinned out.
His team are of the view that the thinning of the ice is not materially responsible for triggering the volcano below Eyjafjallajokull because relatively speaking it is an eruption under a thin ice cap.
The concerns are not limited to Iceland with Carolina Pagli, a geophysicist at the University of Leeds in England, confirming that there were risks that climate change could also trigger volcanic eruptions or earthquakes in places such as Mount Erebus in Antarctica, the Aleutian islands of Alaska or Patagonia in South America.

The more I think about this, the more I’m convinced that reduced pressure on the earth’s mantle would also mean more earthquakes!
Bring back the Ice Age now or we’re all gonna die!
MORE: It appears that the scientists have it wrong. According to Iranian Ayatollah Kazem Sedighi, it’s actually human sexual misbehavior which causes earthquakes:

“Many women who dress inappropriately … cause youths to go astray, taint their chastity and incite extramarital sex in society, which increases earthquakes,” Ayatollah Kazem Sedighi told worshippers at overnight prayers in Tehran.
“Calamities are the result of people’s deeds,” he was quoted as saying by reformist Aftab-e Yazd newspaper.
“We have no way but conform to Islam to ward off dangers.”

He doesn’t mention volcanoes, but I’m sure the same principle is involved.
Via Glenn Reynolds who alludes to the mechanics of shaking but is silent about volcanic eruptions.