Marine Cloud Brightening: A Science Agenda for Scalable Climate Intervention

Marine Cloud Brightening: A Path to Scalable Climate Intervention

Marine Cloud Brightening (MCB) is a geoengineering approach designed to enhance the reflectivity of marine clouds by introducing targeted aerosols, primarily sea salt, into the atmosphere. A 2026 study published in AGU Advances proposes a structured framework to evaluate MCB’s feasibility, risks, and scalability across multiple scales of research.

Understanding Marine Cloud Brightening

MCB operates on the principle that increasing the albedo (reflectivity) of marine clouds can reflect more sunlight back into space, thereby reducing global temperatures. This process relies on the careful injection of sea salt aerosols, which act as cloud condensation nuclei, altering cloud properties and longevity. However, the success of MCB depends on a deep understanding of how aerosols interact with clouds and their surrounding environment throughout their life cycle.

A Framework for Assessing MCB Viability

In their study, Doherty et al. [2026] present a comprehensive framework for studying MCB across different scales, from small-scale experiments to large-scale field studies. The proposed approach includes:

• Characterizing aerosol life cycles: Systematic study of how aerosols evolve from emission to deposition, including their interactions with clouds.
• Analyzing cloud processes: Investigation of the diurnal cycles of cloud formation, development, and dissipation, and how these are influenced by aerosol additions.
• Evaluating aerosol application parameters: Assessment of how varying the magnitude, duration, and type of aerosol injection affects cloud properties and behavior.
• Monitoring environmental impacts: Detection and mitigation of potential harmful effects, such as unintended regional changes in temperature or precipitation patterns.

Stage III Studies: Measuring Local Cloud Responses

The study outlines a possible configuration for a Stage III study, which would focus on measuring local-scale cloud responses to a single plume of generated sea salt aerosol. This stage is critical for understanding the immediate and localized effects of MCB before scaling up to broader applications. The proposed methodology includes:

• Dispersing a controlled plume of sea salt aerosols sized appropriately for marine cloud brightening.
• Monitoring cloud responses in real-time using advanced remote sensing and in-situ measurement techniques.
• Comparing observed cloud properties with baseline data to quantify the impact of aerosol injection.

Key Findings and Implications

The framework proposed by Doherty et al. [2026] emphasizes the need for a multi-scale, iterative approach to MCB research. By systematically characterizing aerosol-cloud interactions and their environmental impacts, scientists can better assess the potential of MCB as a climate intervention strategy. The study also highlights the importance of transparency and collaboration among researchers to ensure that findings are reproducible and scalable.

Citation and Credits

Citation: Doherty, S. J., Diamond, M. S., Wood, R., Hirasawa, H. (2026). Defining scales of field studies and experiments to assess marine cloud brightening. AGU Advances, 7, e2025AV001939. https://doi.org/10.1029/2025AV001939

Editor: Ana P. Barros, AGU Advances

© 2026. The authors. CC BY-NC-ND 3.0

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