Regional Scale Analysis of Climate Extremes in an SRM Geoengineering Simulation, Part 1:Precipitation Extremes

In this study, we examine the statistics of precipitation extreme events in a model simulation of solar radiation management (SRM) geoengineering. We consider both intensity and frequency-based extreme indices for precipitation. The analysis is performed over both large-scale domains as well as regional scales (22 Giorgi land regions). We find that precipitation extremes are substantially reduced in geoengineering simulation: the magnitude of change is much smaller than those that occur in a simulation with elevated atmospheric CO₂ alone. In the geoengineered climate, though the global mean of the intensity of extreme precipitation events is slightly less than in control climate, substantial changes remain on regional scales. We do not find significant changes in the frequency of precipitation extremes in geoengineering simulation compared to control simulation on global and regional scales. We infer that SRM schemes are likely to reduce precipitation extremes and the associated impacts on a global scale. However, we note that a comprehensive assessment of moral, social, ethical, legal, technological, economic, political and governance issues is required for using SRM methods to counter the impacts of climate change.