- biogeochemical cycle moving carbon through atmosphere, biosphere, ocean, and lithosphere
- photosynthesis fixes atmospheric CO2 into organic molecules using solar energy
- respiration and decomposition release CO2 back to the atmosphere
- oceans absorb and release CO2 at the surface, store it in deep waters
- combustion of fossil fuels transfers geological carbon to the atmosphere rapidly
- weathering of silicate rocks consumes CO2 over geological timescales
- volcanic outgassing from plate tectonics returns deep carbon to the atmosphere
- soil holds more carbon than the atmosphere and all plant life combined
- connected to water cycle through dissolved inorganic carbon transport
- disruption of this cycle drives climate change through greenhouse forcing
- thermodynamics governs every transformation in the cycle