The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration to and release from carbon sinks. Carbon sinks in the land and the ocean each currently take up about one-quarter of anthropogenic carbon emissions each year. Humans have disturbed the biological carbon cycle for many centuries by modifying land use, and moreover with the recent industrial-scale mining of fossil carbon (coal, petroleum, and gas extraction, and cement manufacture) from the geosphere. Carbon dioxide in the atmosphere had increased nearly 52% over pre-industrial levels by 2020, forcing greater atmospheric and Earth surface heating by the Sun. The increased carbon dioxide has also increased the acidity of the ocean surface by about 30% due to dissolved carbon dioxide, carbonic acid and other compounds, and is fundamentally altering marine chemistry. The majority of fossil carbon has been extracted over just the past half century, and rates continue to rise rapidly, contributing to human-caused climate change. The largest consequences to the carbon cycle, and to the biosphere which critically enables human civilization, are still set to unfold due to the vast yet limited inertia of the Earth system. Restoring balance to this natural system is an international priority, described in both the Paris Climate Agreement and Sustainable Development Goal 13. Main components The carbon cycle was first described by Antoine Lavoisier and Joseph Priestley, and popularised by Humphry Davy. The global carbon cycle is now usually divided into the following major reservoirs of carbon interconnected by pathways of exchange: The atmosphere The terrestrial biosphere The ocean, including dissolved inorganic carbon and living and non-living marine biota The sediments, including fossil fuels, freshwater systems, and non-living organic material. The Earth's interior (mantle and crust). These carbon stores interact with the other components through geological processes. The carbon exchanges between reservoirs occur as the result of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the