The carbon cycle describes the movement and exchange of carbon among the atmosphere, oceans, biosphere and geosphere. Carbon is stored in major pools including the atmosphere, terrestrial plants, soils, fossil fuels, oceans and sedimentary rocks. Carbon is continuously transferred between pools through natural processes like photosynthesis, respiration, decomposition, combustion and weathering. Human activities like burning fossil fuels have increased the amount of carbon dioxide in the atmosphere, impacting the global climate.