未来能源研究所-太阳能地球工程对温度归因死亡率的影响（英）-2023.5-26页

Summary of "Impact of Solar Geoengineering on Temperature-Attributable Mortality"

Introduction

This paper analyzes the impact of solar geoengineering (SG) on temperature-attributable mortality and compares it to equivalent cooling from emissions reductions. It addresses key uncertainties and risks associated with SG deployment, emphasizing the need for comprehensive risk-risk assessments in climate policy.

Key Findings

• Climate Response: SG reduces temperature-attributable mortality more effectively than emissions reductions per degree of global cooling. SG overcools equatorial regions and undercools polar regions, altering temperature variability, which may better mitigate heat stress risks in populated areas.
• Empirical Impact: Globally, SG reduces temperature-attributable mortality by approximately 17 deaths per 100,000 per year per 1°C of cooling, compared to 9-18 deaths for emissions reductions. Regionally, 68% of the global population benefits from reduced mortality risk, with the greatest benefits in poorer regions, while 32% experience increased risk (higher in Global North regions).
• Risk Comparison: Benefits from reduced mortality risk outweigh direct human mortality risks from sulfate aerosol injection (around 0.3 deaths per 100,000 per year per °C on average), making SG a potential supplement to emissions reductions despite introducing new risks.
• Limitations and Uncertainties: Uncertainties arise from empirical models, climate simulations, and assumptions about income growth, adaptation, and model-specific limitations. Findings are robust to various scenarios, but results depend on regional heterogeneity in climate response and socioeconomic factors.

Conclusion

SG shows potential to significantly reduce climate-related mortality risks, especially with differences in cooling distribution, but it cannot replace emissions reductions due to long-term risks. Further research is needed for comprehensive risk assessments and policy guidance.