Assessment of Regional Disparities in Stratospheric Aerosol Geoengineering Strategies
Due to the slow pace of mitigation, geoengineering, a deliberate modification of the climate system, has been considered a possible supplement to emission reduction. However, most previous research has been focused on a global scale. In this thesis, five existing strategies are investigated. And a comprehensive study of regional inequalities in existing geoengineering strategies is provided through an evaluation of temperature and precipitation changes in 26 Giorgi regions covering the majority of the Earth’s continental area. Geoengineering Large Ensemble (GLENS) is found to be the best single strategy with minimum Root-mean-square (RMS) for both temperature and precipitation residual. Moreover, GLENS is almost better than any other combination of strategies under different objectives. This thesis also uses the Pareto criterion and scaling to find the optimal level of geoengineering that can minimize average regional disparities. Results show that regional equity comes at the cost of inefficient global cooling. The level of geoengineering leading to minimum average temperature residual is 95 percent of the amount of geoengineering that would restore global mean temperature to its baseline value. This level shrinks to 70- 80 percent for precipitation metrics. Moreover, for most metrics, a moderate amount of geoengineering can restore almost every region closer to the baseline than no geoengineering scenario (up to 90 percent for temperature target and decreasing with the weight of precipitation).