[cftm]

A million years? I think you over-estimate how insignificant we are to this planet.

I'm not advocating we destroy the environment, but we really can't do a whole darn lot to it. Can we set off every nuclear weapon at once? Sure, but even that will likely just ruin the surface for 50,000 - 100,000 years. Life will continue, just not humans and most likely nothing of any size.

If we manage to throw the planet into a run-away greenhouse cycle like Venus, yeah, life's done here but that seems like a tall order (though I am not well read or well versed on this subject matter so I could be wrong on this count.

Ok, off the soap-box, you were making the same point as me :)