INDUBITABLY

I always like to contemplate: The future to anticipate.
Although it may not be too subtle,: I'm always there with this rebuttal:
For those who fear the atom's blast: I'd say that judging from the past,
The human race is here to last: Indefinitely.
They've weathered plagues, invasions, pain,: Famine from draught and flood by rain,
So I'm convinced some will remain: Indubitably.