A simple model of the anthropogenically forced CO2 cycle

W. Weber, H.-J. Lüdecke, C. O. Weiss
2015 Earth System Dynamics Discussions  
<p><strong>Abstract.</strong> From basic physical assumptions we derive a simple linear model of the global CO<sub>2</sub> cycle without free parameters. It yields excellent agreement with the observations reported by the carbon dioxide information analysis center (CDIAC) as time series of atmospheric CO<sub>2</sub> growth, of sinks in the ocean and of absorption by the biosphere. The agreement extends from the year 1850 until present (2013). Based on anthropogenic CO<sub>2</sub> emission
more » ... sub> emission scenarios until 2150, future atmospheric CO<sub>2</sub> concentrations are calculated. As the model shows, and depending on the emission scenario, the airborne fraction of CO<sub>2</sub> begins to decrease in the year ~ 2050 and becomes negative at the latest in ~ 2130. At the same time the concentration of the atmospheric CO<sub>2</sub> will reach a maximum between ~ 500 and ~ 900 ppm. As a consequence, increasing anthropogenic CO<sub>2</sub> emissions will make the ocean and the biosphere the main reservoirs of anthropogenic CO<sub>2</sub> in the long run. Latest in about 150 years, anthropogenic CO<sub>2</sub> emission will no longer increase the CO<sub>2</sub> content of the atmosphere.</p>
doi:10.5194/esdd-6-2043-2015 fatcat:5ivpragwizf5lnyfyaacyzbzb4