Professor Ian Plimer could not have said it better! If you've read his book you will agree, this is a good summary.

Okay, here's the bombshell. The volcanic eruption at Iceland's Eyjafjallajokull volcano, since its first spewed volcanic ash, in just FOUR DAYS, NEGATED EVERY SINGLE EFFORT you have made in the past five years to control CO2 emissions on our planet - all of you. And now with Iceland's Grimsvotn volcano erupting on May 21, 2011, it has been a losing battle. Of course you know about this evil carbon dioxide that we are trying to suppress - it's that vital chemical compound that every plant requires to live and grow and to synthesize into oxygen for us humans and all animal life. I know, it's very disheartening... http://rense.com/general94/onevol.htm