More Co2 = less brains?

[Ricardo Segurado]

>Human beings only use 20% of the air they breathe in anyway so even if the
>percentage oxygen in the atmosphere halves (would require *HUGE* raise in
>CO2 levels) then we would still be okay.  

>What i am saying is that unless there is a 3-4000%+ rise in CO2 levels we
>are safe! :)

 This point will bring us way off subject, but plants
would find it hard to photosynthesise with an even modest
(5%) rise in atmospheric CO2. I can't recall the exact
details, but it is a fact. (some plant biochemist please
help me out here...) I'd say a 3000% rise would be
fairly catastrophic: to all life.
 (not that it's going to happen..:)
 r
-- 
 "And I know I was wrong when I said it was
true that it could have been me or been her
inbetween without you."