The same applies to glaciers. Some melt away exposing ancient forests.
So I think the whole climate change discussion should be about the influence of humans on the speed of the change. We know climate was different in our history. But when the climate changes too fast we can't prepare for it.
If the planet had been stable for a couple hundred million years, we'd know there are strong negative feedbacks that keep it stable. Instead we see instability and positive feedbacks.
For example, we see minor amounts of warming caused by orbital variations, followed by massive releases of greenhouse gases bringing several degrees of additional warming. So we know that we only have to warm the planet a little, e.g. by our own greenhouse releases, to tip the planet into a warming cycle that does much more damage than we directly did ourselves.
That's why people keep talking about thresholds and carbon budgets and deadlines. If we take things too far, it will be out of our hands; the planet will keep warming even if we stop our own emissions entirely.
A great introductory source on the geological history of climate, and the evidence for it, is Hansen's Storms of My Grandchildren.
http://news.mit.edu/2019/carbon-threshold-mass-extinction-07...