Carbon Stores and Flows

Building on the overview of the global carbon cycle, this lesson examines each of the four major carbon stores — the lithosphere, atmosphere, hydrosphere, and biosphere — in greater detail, analysing the flows (fluxes) between them and the factors that control the rate and direction of carbon transfers. Understanding the magnitude of stores and the speed of flows is essential for evaluating human impacts on the carbon cycle and predicting future climate change trajectories.

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The Lithospheric Carbon Store

The lithosphere is overwhelmingly the largest carbon store on Earth, containing approximately 65,000,000 GtC in sedimentary rocks alone. This carbon is effectively locked away from the active carbon cycle for millions of years.

Carbonate Rocks