What the problem of a nuclear apocalypse?
Radiation and cold temperature due to nuclear winter :
- Mars has no magnetosphere, meaning radiation on it are already deadly for humans.
- Mars has lower temperature than a nuclear winter on earth can produce.
So, at the very best, living on Mars is as bad as living on earth after a nuclear apocalypse.
Add the absence of life form needed to sustain cultures (insects, bacteria, nutriments produced by billions of years of lifeform on earth, etc)
Add the impossibility to breath.
Add the lower access to energetic ressources (oil, sun, coal, etc)
No mention to the total lack of logistic.
End result, to avoid the effect of a nuclear apocalypse, you think sending people in a place way worse than a nuclear apocalypse is a good idea?
At this point, better to create shelters on earth to save humanity from a nuclear apocalypse.
So again, how sending people to mars will help humanity?