-Overpopulation - too many people; no food, water, housing, etc.
-Pollution - environmental damages
-Global Warming - chlorofluorocarbons, etc.
-War - people killing each other for bad reasons
-Stupidity - general population becoming less concerned with education
-Obesity/Disease - people dying from poor decisions or bad luck
-Habitat Destruction - people destroy nature to make room for more people
-Species Extinction - above practices causing diversity of life to diminish
-Religion - People believe many conflicting ideas