Henry et al. (2025) Marine Cloud Brightening to Cool the Arctic: An Earth System Model Comparison

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

Identification

• Journal: Earth s Future
• Year: 2025
• Date: 2025-12-01
• Authors: Matthew Henry, Haruki Hirasawa, Jim Haywood, Philip J. Rasch
• DOI: 10.1029/2025ef006508

Research Groups

Not explicitly stated in the abstract.

Short Summary

This study is the first multi-model comparison of Arctic marine cloud brightening (MCB) via sea-salt aerosol (SSA) injections, demonstrating that this geoengineering technique can substantially cool the Arctic, maintain sea ice, and preserve the Atlantic Meridional Overturning Circulation without causing robust precipitation changes outside the Arctic.

Objective

• To compare the efficacy and impacts of Arctic marine cloud brightening (MCB) using multiple Earth System Models (ESMs), specifically evaluating a scenario designed to maintain near present-day annual-mean Arctic surface air temperature under a moderate greenhouse gas emissions scenario.

Study Configuration

• Spatial Scale: Global, with a specific focus on the Arctic region.
• Temporal Scale: Long-term climate simulations, assessing annual-mean conditions and scaled-up interventions over time.

Methodology and Data

• Models used: Multiple Earth System Models (ESMs)
• Data sources: Model simulations of sea-salt aerosol injections.

Main Results

• Sea-salt aerosol injection induces cloud and sky brightening, leading to substantial cooling in the Arctic across all three models.
• The mass of sea-salt aerosol required for cooling varies greatly between models due to uncertainties in aerosol-cloud interactions.
• Arctic MCB successfully maintains Arctic sea ice under a moderate greenhouse gas emissions scenario.
• No robust precipitation changes are observed outside of the Arctic, contrary to expectations of large tropical rainfall shifts from hemispheric cooling.
• The Atlantic Meridional Overturning Circulation (AMOC) is shown to be maintained, though the models may not represent all driving processes.

Contributions

• First multi-model comparison of Arctic marine cloud brightening, providing a more robust assessment of its potential.
• Demonstrates the potential for Arctic MCB to mitigate regional warming impacts (e.g., sea ice loss) without significant remote precipitation changes or disruption to the AMOC.
• Highlights the significant inter-model uncertainty in the required aerosol mass for effective cooling, emphasizing areas for future research.

Funding

Not explicitly stated in the abstract.

Citation

@article{Henry2025Marine,
  author = {Henry, Matthew and Hirasawa, Haruki and Haywood, Jim and Rasch, Philip J.},
  title = {Marine Cloud Brightening to Cool the Arctic: An Earth System Model Comparison},
  journal = {Earth s Future},
  year = {2025},
  doi = {10.1029/2025ef006508},
  url = {https://doi.org/10.1029/2025ef006508}
}