Global Carbon Cycle Model

A quantitative model of the biogeochemical cycling of carbon (in Gigatons, GtC) among the atmosphere, biosphere, hydrosphere, and geosphere. Total mass is conserved.

System Reservoirs & Fluxes

Values in GtC (Pools) and GtC/yr (Fluxes)
Atmosphere 800 Terrestrial Biosphere 2000 Hydrosphere (Ocean) 38000 Geosphere (Fossil/Soil) 4000

Controls

Adjust the rate of human carbon extraction and combustion. Notice the effect on the atmosphere and ocean over time.

Total System Mass: 44800 GtC (Conserved)

Scientific Context (HS-ESS2-6)

Carbon cycles continuously between the atmosphere, terrestrial biosphere (plants, soil), hydrosphere (oceans), and geosphere (fossil fuels, rocks). Photosynthesis removes CO₂ from the atmosphere, while respiration and decay return it. The ocean acts as a massive sink, dissolving CO₂ directly from the air. Before human industrialization, these fluxes were largely in equilibrium. The rapid extraction and combustion of fossil fuels transfers carbon from the slow-moving geosphere pool directly into the rapid-moving atmosphere pool, overwhelming the natural sinks and driving climate change.