This little-known factoid might change your mind: an all out nuclear war has less than 1 in 10,000 chance of wiping out mankind[0].
[0] http://www.overcomingbias.com/2012/11/nuclear-winter-and-hum...
[0] http://www.overcomingbias.com/2012/11/nuclear-winter-and-hum...
I was point out how difficult it is to wipe out ~7 billion people, even with extremely advanced technology. Nuclear winter is just a convenient benchmark of that. The same resilience mankind has against nuclear winter is also applicable against genetic engineering, climate change, and nano-tech disasters.