Modeling the far-reaching climate responses of regional geoengineering proposals - Thesis

[Geoengineering News]

https://escholarship.org/uc/item/52k6b1kq#author

Authors: Wan, Jessica Shen Yi

2025

Abstract 

As the impacts of climate change worsen, it is becoming increasingly challenging to avoid irreversible climate damages through greenhouse gas emissions reduction alone. In response, research on a set of proposals to counteract the effects of global warming called solar geoengineering (SG) has substantially grown in the past decade. Marine cloud brightening (MCB) is one proposed SG strategy that would cool the planet by adding aerosols to the lower atmosphere to form brighter marine clouds. While most MCB studies have targeted global mean temperature, interventions for regional climate risk reduction might present a more plausible pathway for future deployment. However, it is uncertain the degree to which regional MCB could achieve local climate benefits and avoid unintended side effects outside of the target region. These uncertainties surrounding regional geoengineering form the foundation for this dissertation. Chapter 1 explores the efficacy of regional MCB in the North Pacific to alleviate extreme heat stress in the Western U.S. By brightening both a remote mid-latitude region and a proximate subtropical patch near the Western U.S., I demonstrate the impact of MCB on teleconnections and regional climate. Chapter 2 dives deeper into the idea of geoengineering teleconnections by modeling the response of El Niño-Southern Oscillation (ENSO) to MCB in the Southeast Subtropical Pacific. By deliberately targeting climate variability, I reframe the possible objectives for SG strategies and identify a plausible strategy for MCB to weaken El Niño consistent with current forecasting capabilities. Chapter 3 expands on the concept of targeted intervention for regional impacts reduction by quantifying the societal impacts of MCB on ENSO. Using the climate model experiments from Chapter 2 and interdisciplinary metrics for economic losses, coral reef bleaching, and marine habitat viability, I demonstrate the potential economic and marine ecosystem benefits of damping El Niño with targeted MCB.

Source: eScholarship