Global Warming "Volcano" argument...help needed

[Flarney]

Whenever I'm talking to global warming deniers they usually trot out the "volcano" argument as their trump card. It goes something like "when a volcano erupts it spews a thousand times more CO2 and other greenhouse gasses into the environment than humans ever could" or some such. Does anyone have a link handy that debunks that?

I know it's bunk, I just don't know how to argue it...I need some ammo. :-)

The obvious argument is that we've always had volcanoes, but have only been burning fossil fuels for ~150 years, which charts closely to the rise in CO2 levels and average temperatures, so the Earth could obviously handle volcanos...

Thanks!