I don't know of any scientists who have claimed CO2 caused the last five major extinctions. As nobody was around to witness them, we can only postulate what caused those mass extinction events. Rapid changes in the climate do rank highly as contenders though.It does not matter why the climate changes rapidly to have mass extinctions, only that it does. We know CO2 influences the climate, and we know it is causing rapid changes in the climate now. What kind of dodo says "CO2 did not definitely cause the last 5 mass extinction events on Earth, so why should we worry"?
