These numbers look like a "What COULD kill us all" rather than a "what WILL kill us all".
Yeah, that's kind of the entire point.
That's not what the OP implied.
What do you think is going to kill off humanity?
Kinda implies "could" and personal opinion.
Yeah but what I got is more of a "This is the most likely scenario" when the list really reads like "This is the most likely to kill humans if it happened."
Or to put it another way:
OP: How likely is this to happen?
Me: If this happened, how likely would it wipe out humanity?
A nanotech weapon is so sci-fi that we have no clue how to deal with it. And like the atom bomb, we'd likely make the weapon before we figured out how to stop it. And since our fleshy bodies are likely not able deal with a nanotech, it could wipe us out before we can deal with it. Remember, washing your hands won't stop the nanites.
Do we have anything similar to nanotech at this time? I always thought nanomachines and the like were in the realm of sci-fi.
http://www.popularmechanics.com/science/health/a14381/this-nanoinjector-inserts-dna-into-cells/Yes.