Hiroshima justified? (was Enola Gay: Burnt flesh and other magnificent technological achievements)

" but when we're talking about a strategy capable of wiping
out the entire human race, this villager refuses to concede any moral
authority to the pro-atomic position."


Question: Wouldn't it take an awful lot of A bombs to accomplish wiping
out the human race?? Then with the A bomb or now with the current
nuclear weaponry?? What percentage of Japan land and / or humans did
the bombing in the two cities wipe out compared to the total land mass
and / or population? I did a Yahoo search and the two cities seem to
still be there and thriving , hotels and all. So the physical land
seems to be still there. I know the Japanese weren't completely wiped
out back then but could it be done today? Do we really have that kind
of arsenal? I mean a country that size literally wiped clean?? Is it
necessary with the current accuracy of what we do have, nuclear or
conventional? Why develop the daisy cutter or that other huge bomb they
recently tested in Florida?? ( I forget it's name at the moment. ) I
guess it would be a question of volume of bombs as compared to the power
of a single bomb.

Those against using the A bomb make it sound like a single nuclear
bomb dropped today would literally disintegrate half of the world. Or
are they more concerned that a nuclear bomb would kill life when coupled
with winds blowing radioactive death along with a bunch of other ripe
conditions to carry the effects of the bomb beyond it's minimal
effectiveness?

Growing up I learned in school that a single bomb could destroy the
whole world. Bad, bad, bad. Reading these current threads, I have seen
that one didn't do it. A second one made Japan surrender, but the
country is still there along with the rest of the world, so the second
one didn't do it. The effects seem relatively localized.