Constraining Adversity: Linear Optimization Methods for Regional Climate Risk Mitigation Using Solar Geoengineering

Abstract

Solar geoengineering presents a powerful set of tools for global climate alteration, with the potential ability to reduce the negative impacts of anthropogenic climate change. While a growing body of geoengineering literature examines mechanisms designed to achieve a large-scale objective such as global mean temperature change reduction, little research has been conducted on the modification of regional climate outcomes through geoengineering. In this paper, I utilize the output of geoengineering simulations conducted in the HadCM3L atmospheric-ocean global climate model to analyze the ability of linear programming optimization methods to modify regional climate objectives. These model simulations utilize Lagrange polynomials and seasonal forcing to construct 12 orthogonal solar geoengineering forcing patterns and approximate the climate outcomes produced by each pattern. To analyze this output, I first conduct a climate objective variance analysis to identify climate outcomes that can be altered through a modification of forcing patterns. I then perform a least-squares regression analysis comparing climate outcomes in target regions to global outcome distributions, in order to assess the covariance between regional outcomes and identify inter-regional climate tradeoff systems. Using the results of these tests, I propose and analyze the effectiveness of mathematical optimization techniques to assess and reduce regional climate risks, using a modified solar geoengineering mechanism constructed from a combination of the HadCM3L dataset’s orthogonal forcing patterns. Finally, I run a series of experiments with the optimized forcing in the high-resolution CESM global climate model, in order to assess the ability of linear optimization performed on a simple climate model to approximate and predict local climate effects in a more complex climate system. Ultimately, the objective of this work is to investigate the possibility of utilizing geoengineering to improve local climate outcomes, with a particular focus on regions susceptible to human-, agriculture- and wildlife-related damage as a result of further climate alteration.