Solar geoengineering impacts on precipitation under projected climate change in Pakistan - Preprint

[Geoengineering News]

https://www.researchsquare.com/article/rs-7552383/v1

Authors: Hassaan Sipra, Muhammad Latif, Nabeel Ahmed, Athar Hussain

08 September 2025

https://doi.org/10.21203/rs.3.rs-7552383/v1

Abstract

The spatiotemporal impacts of sulfate injection into the lower stratosphere under the Geoengineering Model Intercomparison Project (GeoMIP) G4 scenario are studied for Pakistan on projected precipitation relative to the Coupled Model Intercomparison Project Phase 5 (CMIP5)-based Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios. The 69-year projection period (2021 − 2089) is divided into three equal 23-year sub-periods, corresponding to sulfate injection being turned on, ongoing, and turned off. Six state-of-the-art climate models and their ensemble mean revealed high inter-model variability. In G4 relative to RCP 4.5, the Beijing Normal University Earth System Model (BNU-ESM) projected a wetter climate for the 69-year period, at the extremes, and during winter. In contrast, the Commonwealth Scientific and Industrial Research Organization Mark 3L (CSIRO-Mk3L-1-2), Hadley Centre Global Environment Model 2 -Earth System (HadGEM2-ES), and the ensemble mean (Goddard Earth Observing System Chemistry-Climate Model, GEOSCCM) projected a drier (wetter) climate at the lower extreme for assorted sub-periods. In G4 relative to RCP 8.5, the ensemble mean projected a significantly drier climate for all sub-periods, at the extremes, and during summer and winter. At the lower extreme, the Model for Interdisciplinary Research on Climate Earth System Model (MIROC-ESM) projected a significantly drier (wetter) climate during the second (third) sub-period, while at the higher extreme, HadGEM2-ES, MIROC-ESM, and its Chemistry-Climate Model version (MIROC-ESM-CHEM) (BNU-ESM) projected significantly wetter (drier) climates in latter sub-periods. During summer (winter), HadGEM2-ES and MIROC-ESM (BNU-ESM) projected significantly drier climates. These changes in precipitation under G4 are of concern for Pakistan, particularly for policy planning on climate change, extreme precipitation, and seasonal variations linked to flooding and droughts. Further research at the South Asia level can clarify sulfate solar geoengineering’s impacts on regional precipitation patterns.

Source: ResearchSquare