A bio-physically-based model of the human-Earth System applicable to long timescales

Abstract:

The study of humans has largely been carried out in isolation from the study of the non-human Earth system. This isolation has encouraged the development of incompatible philosphical, aspirational, and methodological approaches that have proven very difficult to integrate with those used for the non-human remainder of the Earth system. Consequently, it has proven difficult to develop an integrated understanding of how human goals can be most successfully pursued within the physical constraints of the Earth system, impeding policy development. Here, a simple global model is used to illustrate a new approach, intended to facilitate integration with non-human processes by striving for a consistent physical basis, and intended to provide a birds-eye view of the global human-Earth system on long timescales. The model focuses on properties at the population rather than the individual level, resolves dynamics related to the allocation of time amongst available activities according to state-dependent motivations, and includes quantitative metrics for neural processes and human experience. The illustrative model simulates two waking activities: providing food, and doing something else. Although the illustrative model is a gross simplification of reality, the results suggest a simple relationship to predict first order changes in human population, and shows how neural characteristics and subjective experience can emerge from model dynamics. The approach, which could be called Earth System Economics, provides a flexible strategy that aims to provide physically-based assessments of the past and present, as well as future projections that are oriented towards improving human well-being.