I'm by no means knowledgeable on climatology, but a couple layman's observations.
Firstly climate change. There have been many periods of extreme climate change, ice core samples at the poles have shown this as have fossil records. Homo sapiens had not yet even evolved so it wasnt us who caused them.
As for extinctions, these have occurred throughout prehistory, there was the extinction aound 350 million years ago where 95% of species dissappeared, again evidence in fossil records, and of course the dinosaur extinction which was more recent. None of these were due to homo sapiens.
I don't think we have enough data on our climate, most is no more than 100 years which is a blink of an eye in climatology, to make any predictions.
The last ice age finished about 10 000 years ago, we could just be going through the normal warming cycle. Who knows?
Just my 2c worth I claim no expert knowledge in this area.