The physical universe is composed of matter, energy and space.
Our Creator placed energy sources in the universe, and specifically in the earth, for man to use in his creative and productive acts.
Fossil Fuels do not exist. The crude oil and natural gas was placed in the earth by our Creator. They are not the product of decomposition but of purposeful provision.
Our Creator placed a perfect balance in the earth so that as CO2 increases so does plant life which converts the CO2 back to O2 for human and animal usage.