Carbon cycle[edit]
The carbon cycle describes the fluxes of carbon dioxide (CO
2) between the oceans, terrestrial biosphere, lithosphere,[15] and theatmosphere. Human activities such as the combustion of fossil fuels and land use changes have led to a new flux of CO
2 into the atmosphere. About 45% has remained in the atmosphere; most of the rest has been taken up by the oceans,[16] with some taken up by terrestrial plants.[17]