[obvioustroll]

> All the CO2 currently sequestered in fossil fuels used to be part of our atmosphere.

That's an interesting assertion. I'm not a biologist, but I suspect quite a lot of the carbon in hydrocarbons was locked into other carbon compounds before being taken up by plants and animals.

Consider: the carbonaceous compounds in the shells of mollusks do not come from C02 but from other disolved carbon compounds in the water.

You could just as easily argue that all the carbon in limestone used to be in the atmosphere.