image: Left column shows the change in SSP2-4.5 (mean of 2091-2100) relative to the baseline (mean of 2015-2024); middle column shows the change in MCB (mean of 2091-2100) relative to the baseline; right column shows the change in MCB relative to SSP2-4.5: (A-C) Drought intensity (DI), (D-F) Drought severity (DS), (G-I) Drought frequency (DF) (unit: months per year), (J-L) Drought duration (DD) (unit: months), and (M-O) Drought occurrence (DO). Hatched areas indicate regions where changes are not statistically significant at the 95% confidence level using Welch’s t-test.
Credit: ©Science China Press
This study is led by Dr. Long Cao from the School of Earth Sciences at Zhejiang University and Dr. Jiu Jiang from the College of Geography and Remote Sensing Sciences at Xinjiang University. Based on the Community Earth System Model version 2 (CESM2), the researchers conduct a series of multi-member ensemble simulations under the intermediate emission pathway SSP2-4.5 to comprehensively investigate the response of global terrestrial drought to marine cloud brightening (MCB), a representative solar radiation modification (SRM) intervention. The simulations prescribe sea salt aerosol injection over three subtropical ocean regions, collectively accounting for approximately 12% of the global ocean area.
In this study, the researchers systematically examine the responses of drought-relevant climatic variables and multiple drought characteristics to MCB forcing, and further compare the spatial heterogeneity of drought stress across different terrestrial regions. Their findings reveal that regional deployment of MCB would exert a profound influence on global terrestrial drought patterns.
By the end of the 21st century, MCB could induce a global mean cooling of approximately 0.9°C, which generally alleviates the global land drying trend under the SSP2-4.5 scenario. This is manifested as reductions in global mean drought intensity, severity, frequency, and impacted area. The alleviation is primarily attributed to the substantial suppression of terrestrial potential evapotranspiration driven by MCB-induced cooling.
However, the regional drought responses exhibit considerable complexity. In most tropical and subtropical regions including the African Sahel, South Asia, and Australia, MCB effectively mitigates or even overcompensates for warming-induced drought stress. In contrast, parts of eastern South America and portions of Eurasia would experience exacerbated drought conditions relative to SSP2-4.5. These results indicate that the design of MCB strategies should account for the divergent responses of global and regional drought characteristics.
This study helps to improve the understanding of the overall climate impacts induced by MCB and provides a theoretical foundation for developing regionally tailored climate adaptation strategies aimed at mitigating drought risks.
See the article:
Jiang J, Fang Y, Cao L, Yu X. 2026. Simulated response of global terrestrial drought to regional deployment of marine cloud brightening. Science China Earth Sciences, 69(8): 2824–2838, https://doi.org/10.1007/s11430-025-1837-2
Journal
Science China Earth Sciences