Reply #4: I don't understand how nukes can be so cost effective if the eventuality that something goes wrong

[Shagbark Hickory]

happens, it ends up costing billions of dollars between the damage to agriculture, evacuations, repairs, all kinds of specialists being brought in from all over the world, health costs from all the cancer.

It really isn't cost effective. For this kind of money you could figure a way to have windmills suspended in the air.