He et al. (2025) Stratospheric aerosol injection does not cause stronger Asian monsoon drying than greenhouse gas mitigation

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Environmental Research Letters
• Year: 2025
• Date: 2025-11-21
• Authors: Chao He, Yifeng Peng, Pengfei Yu
• DOI: 10.1088/1748-9326/ae2282

Research Groups

The study involved six climate models participating in the Geoengineering Model Intercomparison Project Phase 6 (GeoMIP6). Specific research groups or institutions are not detailed in the abstract.

Short Summary

This study investigates the impact of Stratospheric Aerosol Injection (SAI) on Asian Monsoon (ASM) rainfall, finding that equatorial SAI causes no additional drying compared to greenhouse gas (GHG) mitigation for the same global mean surface temperature (GMST) cooling, and suggests that well-designed SAI strategies can minimize monsoon failure risk.

Objective

• To determine if equatorial Stratospheric Aerosol Injection (SAI) substantially reduces Asian Monsoon (ASM) rainfall beyond what would occur from greenhouse gas (GHG) mitigation for an equivalent global mean surface temperature (GMST) cooling, and to understand the underlying mechanisms and inter-model variability.

Study Configuration

• Spatial Scale: Global climate simulations, with a specific focus on the Asian Monsoon (ASM) region.
• Temporal Scale: Long-term climate response, assessed through idealized simulations.

Methodology and Data

• Models used: Six climate models participating in the Geoengineering Model Intercomparison Project Phase 6 (GeoMIP6).
• Data sources: Idealized simulations from the participating climate models.

Main Results

• Both greenhouse gas (GHG) mitigation and equatorial Stratospheric Aerosol Injection (SAI) lead to an overall reduction in Asian Monsoon (ASM) rainfall, primarily due to thermodynamic effects associated with decreased atmospheric moisture as global mean surface temperature (GMST) cools.
• Equatorial SAI produces no additional drying over the ASM region compared with GHG mitigation for the same magnitude of GMST cooling.
• Relative to a baseline with comparable GMST, all six models show no substantial drying over the ASM region beyond internal variability.
• A major part of the inter-model spread in ASM rainfall response arises from differences in changes to the meridional insolation gradient, which is influenced by the spatial distribution of aerosols.
• Smaller (larger) insolation reductions over the ASM region relative to the equator favor enhanced (suppressed) ascent air motion and rainfall over the ASM region.
• Single-model simulations with aerosol injections at varying latitudes confirmed the relationship between meridional insolation gradient and ASM rainfall.

Contributions

• Provides evidence that equatorial Stratospheric Aerosol Injection (SAI) does not exacerbate Asian Monsoon (ASM) drying beyond what is expected from greenhouse gas (GHG) mitigation for equivalent global mean surface temperature (GMST) cooling.
• Identifies the meridional insolation gradient as a critical factor explaining inter-model spread in ASM rainfall response to SAI and influencing regional atmospheric circulation.
• Suggests that carefully designed SAI deployment strategies, potentially involving specific aerosol injection latitudes, could effectively minimize the risk of monsoon failure.

Funding

Funding information is not provided in the abstract.

Citation

@article{He2025Stratospheric,
  author = {He, Chao and Peng, Yifeng and Yu, Pengfei},
  title = {Stratospheric aerosol injection does not cause stronger Asian monsoon drying than greenhouse gas mitigation},
  journal = {Environmental Research Letters},
  year = {2025},
  doi = {10.1088/1748-9326/ae2282},
  url = {https://doi.org/10.1088/1748-9326/ae2282}
}