ESDD

Earth System Dynamics Discussions

ESDD

Earth Syst. Dynam. Discuss.

2190-4995

Göttingen, Germany

10.5194/esd-2023-21

Gaia: Complex systems prediction for time to adapt to climate shocks

Hunt

Allen G.

¹ Sahimi

Muhammad

² Faybishenko

Boris

³ Egli

Markus

https://orcid.org/0000-0002-1528-3440

⁴ Kabala

Zbigniew J.

https://orcid.org/0000-0002-3502-7081

⁵ Ghanbarian

Behzad

⁶ Yu

Fang

⁷

Department of Physics, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA

Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA

Energy Geosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA

Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland

Department of Civil & Environmental Engineering, Duke University, Durham, NC 27708, USA

Porous Media Research Lab, Department of Geology, Kansas State University, Manhattan, KS 66506, USA

Department of Forestry, Beihua University, 3999 Binjiangdong Road, Jilin, China, 132013

27 09 2023

2023 1 13

2023

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://esd.copernicus.org/preprints/esd-2023-21/

The full text article is available as a PDF file from https://esd.copernicus.org/preprints/esd-2023-21/esd-2023-21.pdf

Earth’s climate has undergone significant fluctuations in the geologic past. We focus on the glacial episodes that followed the major waves of invasion of land plants. Twice in Earth’s history the impacts of land plant innovations on the atmosphere through increased CO2 drawdown have precipitated sufficient cooling to produce ice ages. Each time, however, adaptation of soil ecosystems eventually helped re-establish apparent steady-state conditions, i.e., new equilibrium temperature and atmospheric CO2 content, ending each of the glacial episodes. In each case, the time interval between the initial innovation and the emergence from the glacial episode was approximately 60 Myr. The consistency of the time scale of the response invites an explanation in terms of a universal rate of dispersal of genetic information that encapsulates the biogeochemical cycle of cellulose production and decay. In this paper, we postulate that the long time for adaptation is a consequence of the time required for the spread of an entire clade though the soil to continental scale. Although 60 Myr appears to be a long time, it is very short compared to the time required for diffusion to transport even molecules like HCO3− or sugar through the soil over a continental distance of 5,000 km, which is between 1014 and 1016 years for solutes with such soil diffusion constants in the range 10−11 m2 s−1. Horizontal solute transport through heterogeneous media by advection might be considered as a dispersal mechanism, but is also known to require enormous time scales (ca. 150 Myr for 500 m). We also seek a relevant mechanism in the known scaling of plant and fungal growth rates as a function of time, which can facilitate as well the movement of bacteria, and predicted these rates theoretically on the basis of the universal optimal 2D paths tortuosity from percolation. Comparison with actual data pairs (7,000) for plant and fungal growth rates were used to verify these predictions over 13 orders of magnitude of time, from about one minute to 100 kyr; extrapolation over less than three additional orders of time yields a continental-scale transport time of 80 Myr. We now interpret this prediction in terms of Margulis’ understanding of emergent behavior of coupled (soil and plant) ecosystems responding to climate shocks induced by plant innovations.