"A 'greenhouse Earth' is a period during which no continental glaciers exist anywhere on the planet... Earth has been in a greenhouse state for about 85% of its history... Earth is now in an icehouse state, and ice sheets are present in both poles simultaneously."
You don't warm the earth rapidly (which at this point we undeniably are) and then magically get back "normal" fern forests and dinosaurs or whatnot. What you get is a mass extinction.
Eventually, things will evolve to forests or the equivalent. You'll be unlikely to have the same kinds of dinosaurs as before, but as the old saying goes, nature like carcination. There will probably be new variants of crabs.
You seem to be saying the equivalent of e.g. "It's OK to kill all the elephants because in a few million years something else will have filled the niche". That seems ridiculous to me.
Does your logic extend to all species? All ecosystems? Our species?
In fact what you're describing is exactly the disconnect: libertarianism is very much not "conservative" by traditional standards. The fact that they live in the same party in the modern US is an accident; it doesn't follow from their philosophies at all.