Assessing the stability of glacial-interglacial cycles: a stochastic model analysis of Earth system resilience
- 1Potsdam Institute for Climate Impact Research, Member of the Leibnitz Association, 14473 Potsdam, Germany
- 2Niels Bohr Institute, University of Copenhagen, Copenhagen, DK-1165, Denmark
- 3Stockholm Resilience Centre, Stockholm University, SE-106 91 Stockholm, Sweden
- 4High Meadows Environmental Institute, Princeton University, Princeton, USA
- 5Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam, Germany
Earth system stability commonly denotes the continuation of the Holocene's relatively stable climatic and ecological conditions essential for human civilisation, whereas Earth resilience describes the Earth system’s ability to recover from significant disturbances, such as the transgression of any of the nine planetary boundaries. Given the nature of the Earth system as a non-autonomous, stochastic, non-linear system, it is not clear what exactly constitutes stable states, semi-stable states or mere transients. An alternative approach is to regard the glacial-interglacial cycle as a stable attractor and thus ask, how stable or resilient is this cycle to perturbations? The answer could provide insights relevant for contextualising the embedded transitions of critical tipping points happening on much shorter time scales.
In this study, we explore the stability and resilience of the glacial-interglacial cycle using a conceptual climate model developed by Talento and Ganopolski (2021), based on atmospheric CO2 concentration, global mean temperature, and global ice volume. The model is driven by astronomical forcing and replicates the ice age cycles of the last 800,000 years with a correlation of 0.86. Following the classical idea of Hasselmann, we have extended this model with additive noise to represent unresolved processes. An analysis of an ensemble of trajectories reveals periods of significant divergence and convergence, indicating that the model’s sensitivity to noise varies in response to astronomical forcing. We have further applied a transfer operator approach in an attempt to identify stable and decaying states of the model and to study their evolution with changes in astronomical forcing. Findings shed light on the complexity and sensitivity of the Earth system's dynamics.
References:
Talento, S., & Ganopolski, A. (2021). Reduced-complexity model for the impact of anthropogenic CO2 emissions on future glacial cycles. Earth System Dynamics, 12(4), 1275-1293.
How to cite: Harteg, J. S., Wunderling, N., Klose, A. K., and Donges, J. F.: Assessing the stability of glacial-interglacial cycles: a stochastic model analysis of Earth system resilience, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15457, https://doi.org/10.5194/egusphere-egu24-15457, 2024.
