It's not a matter of optimism, it's a matter of not repeating our parents' mistakes. Whatever the inevitability of warming, we should fight for every 0.1°C, because there's a big difference for our kids if the average is 2 or 5 or 6 degrees higher.
You can be as pessimistic as you feel the need to, as long as that doesn't stop you from acting.
It's not a matter of optimism, it's a matter of not repeating our parents' mistakes. Whatever the inevitability of warming, we should fight for every 0.1°C, because there's a big difference for our kids if the average is 2 or 5 or 6 degrees higher.
You can be as pessimistic as you feel the need to, as long as that doesn't stop you from acting.