[ESAC Seminar] Perrin Davidson

“Hierarchical Organization of Earth System Dynamics”

We analyze Earth system dynamics reconstructed from isotopic proxy records of the climate-carbon cycle over the last 6.6 × 10^7 yr. These records reveal a hierarchical organization of all analyzed climate-carbon cycle fluctuations across timescales of 1 × 10^3 < T < 5 × 10^6 yr. Across this hierarchy, a simple damping mechanism saturates with fluctuation magnitude, apparently contradicting previous theories which assume that the restoring tendency is proportional to the system’s departure from equilibrium. Here, we propose a new theory that predicts the cumulative distributions and power spectra of all analyzed climate-carbon cycle fluctuations in agreement with empirical estimates within their uncertainties. The theory assumes a hierarchy of carbon cycle elements with rates inversely proportional to carbon age. It predicts that fluctuation variance increases linearly with carbon age in the absence of climate damping mechanisms but becomes independent of age when those mechanisms are present. Together, the observations and theory suggest that this shared structure across fluctuation timescales reflects primary control by the carbon cycle, to which climatic processes respond.

ESAC Early-Career Seminar Series —

A forum for students and postdocs to share recent research, hone presentation skills, and build community among peers, sponsored by the EAPS Student Advisory Committee. Open to current EAPS graduate and undergraduate students and postdocs. Typically hosted on Thursdays during the semester, including pizza lunch.

Contact: esac.officers@gmail.com