Like the water cycle, carbon takes different forms as it cycles through the ocean, land and atmosphere.
In the gaseous form — carbon dioxide — it is absorbed by vegetation, which in turn is eaten by animals. At death, the carbon is returned to the soil as organic matter — accumulating over the eons into coal and oil deposits.
Since the onset of the industrial revolution, however, burning of these fossil fuels has created an imbalance in the cycle leading to a steady increase in atmospheric CO2.
Preindustrial CO2 … » More …