Overview

The global carbon cycle is a key aspect of life on Earth, linking together the living and the non-living, coupling the land, atmosphere, ocean and human spheres. Importantly, the carbon cycle also unites or integrates processes on timescales of seconds (photosynthesis itself) to the geological (formation and weathering of carbon-bearing rock and oil deposits). Because one of the phases of carbon in the Earth System, carbon dioxide, is a potent greenhouse gas, carbon plays a central role in the Earth's climate. As the backbone of most biotic compounds, carbon also plays the central chemical role in life on planet Earth. Carboniferous fossil fuels are our civilisation's primary energy source, making the carbon cycle a central feature of socio-economic processes and politics. All this makes the carbon cycle one of the great intellectual and practical subjects of science in the latter 20th and 21st centuries. In this chapter, I will review the basic structure of the carbon cycle, the contemporary carbon budget, some practical implications of the way the carbon cycle works and how...