Thecarbon cycleis the biogeochemical cycle by whichcarbonis exchanged among thebiosphere ,pedosphere,geosphere,hydrosphere, and atmosphereof the Earth. Along with thenitrogen cycleand thewater cycle, the carbon cycle comprises a sequence of events that are key to making the Earth capable of sustaining life; it describes the movement of carbon as it is recycled and reused throughout thebiosphere.
Theglobal carbon budgetis the balance of the exchanges (incomes and losses) of carbon between the carbon reservoirs or between one specific loop (e.g., atmosphere ↔ biosphere) of the carbon cycle. An examination of the carbon budget of a pool or reservoir can provide information about whether the pool or reservoir is functioning as a source or sink for carbon dioxide.
The carbon cycle was initially discovered by Joseph PriestleyandAntoine Lavoisier, and popularized byHumphry Davy.
