In all the current carbon cycle models,geological processes (including karst) are considered as long term and negligible. The ammount of Carbon in world carbonate rocks is 10exp16 tonnes and makes 99.55% of the total carbon reservoir on the Earth. Because 120 Kg of carbon is removed from the atmosphere for every tonne of limestone rock dissolved, and vice versa, whether karst processes are slow and long term or not become essential for the estimation of CO2 change in the atmosphere,i.e, the so-called carbon sink and source problem. The works of the UNESCO/IUGS IGCP 379 "Karst processes and the Carbon cycle" showed that the Karst Dynamics System is very sensitive to environmental changes,including the change of CO2 in atmosphere, i.e, the increase of CO2 in atmosphere will enhance the dissolution of carbonate rock, and thus increase the CO2 uptake from the atmosphere. Global carbonate rocks are buffering the change of CO2 in the atmosphere.