Fossil fuels implies, that at one time, that the same carbon was not fixed, but was part of the earth's carbon cycle. The CO2 was sequestered by life, which then dies, decays to make fossil fuel. At one time all the fossil fuels, including what is still in the ground was part of the active carbon cycle of the earth. Life was still able to evolve and the earth was not destroyed.
Sequestering the original high concentrations of CO2, by life, changed the planet. If we had been around when the CO2 was really high; before any fossil fuels had formed, and we saw life sequestering the carbon, the liberals would be afraid of that. They would correlate extremely high CO2 with what is supposed to be normal, while not taking into account earth's evolution base on life.
Fossil fuels formed beginning about 300 million years ago accord to the DOE. The quote s from their web site.
Below is CO2 and temperature data for the relationship between atmospheric CO2 and Temperature, when the carbon cycle contain far more CO2 than today such as before any fossil fuels has formed. I expected much high temperatures based on the 100 year computer models. If we burnt all the fossil fuels in the earth global temperature will peak at 25C. This same temperature was reached even with 250 million years of carbon sequestered and stored as fossil fuels. How is that possible using the current logic?
Methane, the peak of a Milankovitch cycle and complete loss of polar ice.