An existential risk (or x-risk) is a risk posing permanent large negative consequences to humanity which can never be undone. In Nick Bostrom's seminal paper on the subject 1, he defined an existential risk as:
One where an adverse outcome would either annihilate Earth-originating intelligent life or permanently and drastically curtail its potential.
The total negative impact of an existential risk is one of the greatest negative impact known. Such event could not only annihilate life as we value it from earth, but would also severely damage all Earth-originating intelligent life potential....