Who knows if climate change will be an extinction event for humanity? When things get dire humanity turns to war and there's a lot of nuclear armaments at our disposal. Would it be insane to wage such warfare? Yes. But when crops are failing, cattle are dying and our civilization is undergoing extreme duress don't rule out our resorting to the insane. I think the hope is we're 50-150 years (or more) from things getting that dire and perhaps we'll have a technological solution to the problem. I hope so, but hope is not a strategy.