# Robustness of Gaian Feedbacks to Climate Perturbations

## TL;DR

This study investigates how Gaia-like biospheres respond to climate perturbations, finding that gradual environmental changes are less disruptive and that Gaia feedbacks can maintain habitability despite planetary disturbances.

## Contribution

It introduces climate perturbations into the ExoGaia model to assess the resilience of Gaia feedbacks under realistic planetary disturbances.

## Key findings

- Gradual climate changes allow biospheres to survive larger perturbations.
- Rapid perturbations are more likely to disrupt Gaia feedbacks.
- The magnitude of environmental change impacts biosphere resilience more than the change's sign.

## Abstract

The Gaia hypothesis postulates that life regulates its environment to be favorable for its own survival. Most planets experience numerous perturbations throughout their lifetimes such as asteroid impacts, volcanism, and the evolution of their host star's luminosity. For the Gaia hypothesis to be viable, life must be able to keep the conditions of its host planet habitable, even in the face of these challenges. ExoGaia, a model created to investigate the Gaia hypothesis, has been previously used to demonstrate that a randomly mutating biosphere is in some cases capable of maintaining planetary habitability. However, those model scenarios assumed that all non-biological planetary parameters were static, neglecting the inevitable perturbations that real planets would experience. To see how life responds to climate perturbations to its host planet, we created three climate perturbations in ExoGaia: one rapid cooling of a planet and two heating events, one rapid and one gradual. The planets on which Gaian feedbacks emerge without climate perturbations are the same planets on which life is most likely to survive each of our perturbation scenarios. Biospheres experiencing gradual changes to the environment are able to survive changes of larger magnitude than those experiencing rapid perturbations, and the magnitude of change matters more than the sign. These findings suggest that if the Gaia hypothesis is correct, then typical perturbations that a planet would experience may be unlikely to disrupt Gaian systems.