There wont be another world war. There will be a war between two or three countries but not world war. At worst if that happens then it will be an end of humans because it will be a nuclear war. If miners stops mining the bitcoin then bitcoin will have no value. I hope WW3 wont happen
Yes, in the event of a global war with the use of weapons of mass destruction, I think it will be the end of the world and not just Bitcoin.
A world war cannot be predicted, but there is a possibility that it will happen.
As for the power outages, they can be replaced by alternative energy to continue mining Bitcoin, In the event that armies target places of power generation.