I did not follow the complete doomsday theory just in case you noticed. (Destruction of life on earth due to Venus atmosphere conditions).
My doomsday theory goes at max that if we humans dally on long enough, we'll hit conditions that send our civilization, comfort, technology, whatever you name it, reeling back to the level of hundreds or thousands of years ago in most places of the earth, along with some serious disasters in the process.
IMHO there are still going to be pockets that may be so-so-okay, notably on areas with protection of natural barriers.
(When the crap goes on the loose,the biggest danger may be other humans....for some)