[finnman69]

Your post demonstrates an almost complete lack of knowledge regarding the past climate history of the planet.

You want to offer a correction then or was that just a hit and run?

[cogitator]

but there is no obvious correlation between atmospheric CO2 and planetary temperature over the last 600 million years, so why would such relatively tiny amounts suddenly become a critical factor now?

It's hard to figure out where to start, but this will be a start:

CO2 and Climate Change

Concluding comments: "The first-order agreement between the CO2 record and continental glaciation continues to support the conclusion that CO2 has played an important role in long-term climate change. The Veizer et al. data, if correct, could be considered a Phanerozoic extension of a possible dilemma long known for the early and mid-Cenozoic. To weigh the merits of the CO2 paradigm, it may be necessary to expand the scope of climate modeling. For factors responsible for the presence or absence of continental ice, the CO2 model works very well. In contrast, there are substantial gaps in our understanding of how climate models distribute heat on the planet in response to CO2 changes on tectonic time scales. Given the need for better confidence in some of the paleoclimate data and unanticipated complications arising from altered tectonic boundary conditions, it may be hazardous to infer that existing discrepancies between models and data cloud interpretations of future anthropogenic greenhouse gas projections."