Mass extinctions are a natural event on planet earth. Earths climate has been changing since day one. Technically we are coming out of a nice age, and between glacial periods. The overwhelming vast majority of all creatures and plant fauna that has ever lived on Earth is extinct, and went extent before modern humans evolved. If you put earth existence on a clock, with 00:00 being the second earth was formed, and 12:00 being right now, then modern man didn't appear until 11:52, and when I say modern man I mean people with spears.
"When the people fear their government, there is tyranny; when the government fears the people, there is liberty."