Yesterday's spectacular explosion of Iceland's Eyjafjallajökul volcano partly melted the glacier above and not only caused a major flood resulting in the evacuation of seven hundred people, but has also left air passengers stranded across six continents!

The ice-capped volcano initially erupted on March 20th, but did not cause much damage. Just as that was petering off, this new eruption which spewed from a different vent has caused three holes in the glacier and managed to grind to a halt the world's busiest air routes, thanks to the large spews of ash that have engulfed a large part of Europe.

When the Eyjafjallajökul glacier last erupted in 1821, it spewed lava and ash on and off for over a year. While this could be a problem, the scientists are more worried that if the lava continues to flow and melts the top of its neighboring glacier, Katla - it could also blow up and cause an even bigger eruption, one that could not only disrupt air traffic, but also, result in global cooling. That's because when volcanic ash reaches the stratosphere, it remains there for a long time, blocking the sunrays from getting to Earth.

The extent of global cooling will depend on how high the ash plumes get. When Chile's Mount Pinatubo erupted in 1991,its ash spewed over 700,000 feet into the stratosphere and resulted in cooling down temperatures worldwide by four degrees Celsius for a whole year!

Formed by a series of volcanic eruptions about 20 million years ago, Iceland is home to 130 volcanic mountains. While only 18 of them have been active since it was first inhabited, they are responsible for spewing out a third of the world's total lava output - And it looks like they are just getting warmed up!

sources:usatoday.com,wikipedia.com, washington.com, online.wsj.com