thats also true
but thats the reason why we're warming up, too.
the sun causes ice ages.
it warms up after a period of time (becoming more active) and goes into a less-active state, cooling the world down.
we never used to have ice ages, but now we do, due to the Co2 being below 1%. if we bring it up, we would never have ice ages.
but, simply, we still cannot affect the Co2 levels. lemme tell you:
humans alone release some 32 billion tons of Co2 a year. now nature? some 26 billion GIGATONS a year.
what does that tell you?