We are a lot of people, tied to hard built cities, and depend on a lot of things running smoothly (food, comunications, world peace, and more). Disrupt that (an

We are a lot of people, tied to hard built cities, and depend on a lot of things running smoothly (food, comunications, world peace, and more). Disrupt that (and the way the climate is changing will disrupt everything) and you won't be able to sustain a civilization like ours. And as AIDS, it won't kill you, but it may put you in a position where otherwise minor problems may become lethal (wars, plagues, self-destructive social trends, etc)