Your conclusion is not supported by your premise. Reversion to a mean implies convergence to a stable, unmoving equilibrium. This requires that all forces are restoring forces in the vicinity of that equilibrium. While Earth's climate does have several restoring forces around the current equilibrium, there is one force in particular that is being relatively rapidly shifted away from the current equilibrium: the greenhouse effect. Both simulation and observation provide evidence that this force is sufficiently strong to destabilize the current climate equilibrium.
You are traveling towards a concrete wall at 100 mph. It's all fine, we've been here before... moving at 1 mph.
Yes, Earth had been hotter and cooler, oceans had been higher and way lower... What is objectively novel is velocity of the current climate change. That is terrifying because we don't know if planetary feedback mechanisms can handle that. Looking at Venus, the worst case scenario is pretty bleak, but probably unlikely given further distance from the sun.
Venus's atmosphere is 96.5% carbon dioxide, orders of magnitude more than the 0.04% found on Earth.
Most of Earth's original CO2 is tied up in the kilometers of carbonate rocks that cover a substantial portion of the Earth's surface. That's not going anywhere.
I would love to know more about that, what resources would you recommend? Concur that mostly CO2 atmosphere is highly unlikely, what do you think about melting Siberian permafrost releasing localized methane and accelerating melting feedback loop?
