EAPS

PAOC colloquium: Dan Rothman
Date Time Location
December 3rd, 2018 12:00pm-1:00pm
Title


Earth's Excitable Carbon Cycle


Abstract


The history of the carbon cycle is punctuated by enigmatic transient changes in the ocean's store of carbon. Mass extinction is always accompanied by such a disruption, but most disruptions are relatively benign. The less calamitous group exhibits a characteristic carbon flux whereas greater surges accompany mass extinctions. But why?

Analysis of a two-component dynamical system suggests that disruptions are initiated by perturbation of a permanently stable steady state beyond a threshold. The ensuing excitation exhibits the characteristic surge of real disruptions. In this view, the excitation threshold and the characteristic flux are properties of the carbon cycle itself rather than its perturbation. Surges associated with mass extinction, however, require additional inputs from external sources such as massive volcanism. Modern inputs from anthropogenic emissions may exceed the excitation threshold during the present century.