Triggering A Climate Change Dominated "Anthropocene": Is It Common Among Exocivilizations?

TL;DR

This paper models the coupled evolution of planets and civilizations to determine if climate-driven anthropocene states are a common outcome of technological development, highlighting the role of energy harvesting and planetary feedbacks.

Contribution

It introduces a coupled model of planet-civilization evolution that predicts climate degradation due to energy harvesting, exploring conditions leading to anthropocene-like states.

Findings

Civilizations often trigger climate-dominated anthropocene states.

Planetary feedbacks can truncate civilization growth.

High $CO_2$ levels are detrimental to habitability.

Abstract

We seek to model the coupled evolution of a planet and a civilization through the era when energy harvesting by the civilization drives the planet into new and adverse climate states. In this way we ask if triggering "anthropocenes" of the kind humanity is experiencing now might be a generic feature of planet-civilization evolution. In this study we focus on the effects of energy harvesting via combustion and vary the planet's initial atmospheric chemistry and orbital radius. In our model, energy harvesting increases the civilization's population growth rate while also, eventually, leading to a degradation of the planetary climate state (relative to the civilization's habitability.) We also assume the existence of a Complex Life Habitable Zone in which very high levels of $CO_2$ are detrimental to multi-cellular animal life such as those creating technological civilizations. Our models show that the civilization's growth is truncated by planetary feedback (a "climate dominated anthropocene") for a significant region of the initial parameter space.