photo: AP/Icelandic Coastguard
Just to reassure the more apocalyptic leaning readership we may have: According to scientists from the University of Colorado, Boulder the vast volcanic ash plume coming out of Iceland's Eyjafjallajökull, currently disrupting air travel into and across Europe, will likely dissipate in the next few days and doesn't pose a threat to world climate. Phew...But more seriously, CU's Professor Brian Toon said,
The amount of sulfur dioxide spewed by the volcano so far poses no threat to world climate as determined by an instrument aboard NASA's Aura satellite. But...an apparently larger eruption of an Icelandic volcano in 1783 --which was written about by Benjamin Franklin -- caused some climate issues in Europe by creating smog-like conditions in London that partially blocked out the sun and persisted through the summer months.
Toon suggested though that had the plume been higher, while air travel wouldn't have been disrupted, the threat could have been greater: "Fortunately, the plume...is below the stratosphere, where volcanic gases can have global effects because the lack of rain there prohibits the removal of volcanic material."
Some Geoengineering Schemes Propose Just This...
To bring up a slightly less immediate concern: Consider that some of the wilder geoengineering schemes propose doing just what Toon says isn't happening here and that being a good thing--mimicking a massive volcanic explosion to try to cool the planet.
More on Natural Disasters:
Iceland's Volcanic Eruption: More Tourists, Colder US Winter
Volcanic Haze Closes British Airports, Continent Cut Off
Alaskan Volcanoes to be Surveyed, Tapped for Geothermal Power