Most of the planet's carbon reservoires are stored in the lithosphere, such as in limestone, containing calcareous skeletons of marine organisms, and in sedimentary rocks originating from organic carbon from formerly living creatures. If the remains of dead living organisms accumulate faster than they would decay, in the right environment they might be converted into crude oil, coal or natural gas.
Slow carbon cycle means the lasting transformation of coal between rock, soil, atmosphere, and ocean taking place through hundreds of millions of years. Carbon cycles regulate the Earth's climate as a thermostat. Without human intervention, fossil fuels would be released into the atmosphere in slow cycles over millions of years as a result of volcanic activity. However, as humans extract the coal reserves accumulated over hundreds of millions of years by burning oil, coal and natural gas, or even virgin forests, carbon reservoires release into the fast cycle and increase the carbon dioxide level of the atmosphere, which also causes irreversible changes in the climate. Human activity is responsible for 100-300 times of the present volcanic carbon dioxide emissions.

The energy surplus of coal, oil, and natural gas has made it possible for the lifestyles of modern technological societies to evolve based upon the ideologies prevalent in the last century: endless acceleration, development and accumulation. The societies of the 'Capitalocene' have begun to extract the energy and material resources accumulated in the ecosystem at tremendous concentration and speed. Earth has huge 'cheap' reserves of fossil fuels, human species have less to fear about the depletion of reservoires than the loss of their own living conditions as a result of burning those fossil fuels.