as per the theory of co2 precipitating the Permian extinction, i am aware of some very recent research that makes the claim that the extinction entirely happened during an 80,000 year ice age on the border of the Permian and Triassic periods. (https://www.sciencedaily.com/releases/2017/03/170306091927.h...)
if the data are correct, it seems pretty convincing to me that it wasn't the warming that caused that extinction.
btw, your point about the planet not being destroyed is well taken. i guess what i'm trying to understand is how the positive feedback loop of temp->co2->temp is broken if trace amounts of co2 is such a massive forcing. when the earth had 4000+ ppm of co2 in the atmosphere, there had to be some other, much stronger, forcing to bring the temperature back down.
> but, if this were really how it happened and co2 is the overwhelmingly main forcing for temperature increase, then why wasn't the planet already destroyed back when we had 10x+ the amount of carbon in the atmosphere than what we are doing today?
A sharp increase in CO2 is thought to be one of the precipitating factors in the Permian extinction, which wiped out >70% of land-dwelling vertebrates and >90% of all marine species. No credible person is saying the planet is threatened by climate change, they're saying humans are. This planet, and even life itself, will go on no matter what happens - cold comfort taken against the damage it could cause to our species.