A Model Study Exploring the Decision Loop Between Unilateral Stratospheric Aerosol Injection Scenario Design and Earth System Simulations

[Geoengineering News]

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024EF005455

Authors

Chenrui Diao, Patrick W. Keys, Curtis M. Bell, Elizabeth A. Barnes, James W. Hurrell

First published: 14 May 2025

https://doi.org/10.1029/2024EF005455

Abstract

Stratospheric aerosol injection (SAI) is being discussed as a possible approach to reduce future global warming in addition to emission cuts, and numerous scenarios and Earth system model (ESM) experiments have been developed to explore its effectiveness and risks. Given the complex geopolitical, economic, and strategic considerations among countries, global cooperation in SAI deployment will be challenging. Unilateral SAI deployment has thus been highlighted as an important research topic, although it has been explored very little in scenario design and ESM studies. Inspired by a novel game theory model and a newly developed framework for identifying geopolitically plausible SAI initiator(s), this paper builds a framework for integrating unilateral SAI scenario design, geopolitical game theory, ESM simulation, and climate analyses into a single decision loop. We design and simulate a geopolitically plausible scenario of the initiation of unilateral SAI using the Community Earth System Model, and explore two independent plausible unilateral SAI reaction scenarios following the climate storylines under the initiator scenario. Our work demonstrates an approach to explore the complex feedbacks between unilateral SAI deployment scenarios and the simulation of the subsequent climate storylines.

Key Points

We design a framework to explore the complex feedback loop between unilateral stratospheric aerosol injection (SAI) scenarios and climate storyline simulations

The framework integrates scenario design, geopolitical game theory, climate modeling, and climate analyses into one decision loop

We use simulations to demonstrate how the feedback loop can be applied to explore scenarios and storylines under unilateral SAI deployment

Plain Language Summary

Stratospheric aerosol injection (SAI) is widely discussed as a possible way to help reduce some of the impacts of global warming. Given the complicated geopolitical, economic, and strategic considerations among countries, it may be more likely that one country could initiate SAI deployment alone rather than through global cooperation. Past work has designed a geopolitical game theory model to identify plausible unilateral SAI initiators. Inspired by this work, we build a framework that combines geopolitical game theory and climate modeling into one decision loop. Using this approach, we design plausible unilateral SAI scenarios and explore the climate storylines under them. The framework introduces an approach to better explore complex unilateral SAI problems by linking geopolitical game theory and climate modeling together.

Source: AGU