Not kooky. The state of environments and their constituent organisms is a dynamic thing, which depends greatly on the physical conditions. The state of the atmosphere is one of them. Rainfall and temperature are others.
Consider what happened to the Sahara desert. It seems to flip back and forth from being a desert as it is today to being a fairly well-watered plain, on a timescale of a few thousand years, maybe even just 1000 years. In that time it goes from an ecosystem of grass and trees with elephants and rhinos to now, where in much of it the highest life form is the jerboa (desert rat).
The reason for that seems to be linked to global temperatures. For instance Sahara rainfall seems to have greatly increased during the “little ice age”, the 16th-18th centuries, and much of it turned green.
Oh come on. The sahara flipped green to brown over and over WAY before the industrial revolution!! Go away....
The more CO2 the better. At the current 430PPM we could double it in 100 years if we try hard enough.