The Doomsday Vault

They are building a doomsday vault in the Arctic. Meter-thick walls of reinforced concrete, two airlocks, high security blast-proof doors will protect the seeds from natural disasters. Or nuclear war.

(35, 000 warheads still aiming at each other.
Immediate environment:
blast
thermal pulse
neutrons
x- and gamma rays
radiation
electromagnetic pulse
ionization of the upper atmosphere.
Blast effect:
ground shock
water shock
blueout
tens of millions of degrees
centigrade
cratering
dust
radioactive fallout)

Or in a thousand years the reinforced walls crack on the melting permafrost and the winds carry the spoils out into an uninhabited world.