Griffo & Dude there are two points you seem to want to ignore. 1-Most of the historical climate changes you allude to took place over very long periods of time so life had time to adapt. 2- The ones that were sudden wiped out a very large % of life on earth.
One hundred years over the geological time scale is a blink of the eye. You don't have time to grow fins and learn to live in an acidic sea. A 2-6 deg average temp rise (no matter how much FGD135 wants to deny it) over the whole planet is a very large change and no one really knows how it will play out. I do think it's like messing with a mother-in-law - not worth doing.
Cheers RA