1. Machine intelligence, traditionally called artificial intelligence, which surpasses human intelligence.
2. Your category (b) is generally the primary concern in these types of discussions.
3. The anecdote of the progress of humanity. Compare the impact of human life/intelligence vs. evolutionary relatives like chimpanzees. I do not know that chimps have hunted species out of existence, for instance, but people have. We have also incidentally wiped out populations in efforts to make our lives better (via things like leveling forests, etc.)
2. Your category (b) is generally the primary concern in these types of discussions.
3. The anecdote of the progress of humanity. Compare the impact of human life/intelligence vs. evolutionary relatives like chimpanzees. I do not know that chimps have hunted species out of existence, for instance, but people have. We have also incidentally wiped out populations in efforts to make our lives better (via things like leveling forests, etc.)