I think some people completely miss the point of past natural warming events. All past events were naturally triggered and as a consequence of this initial warming, atmospheric CO2 levels rose and amplified the warming. The natural triggers would have included, inter alia, orbital changes and ocean circulation changes.
This round of climate change is different. We humans have dumped and continue to dump, massive quantities of CO2 into the atmosphere. This time it is atmospheric [CO2] initiating the warming event.
There has never been a climate change like this one.
