Observational constraints suggest a smaller effective radiative forcing from aerosol–cloud interactions

Park, Chanyoung; Soden, Brian J.; Kramer, Ryan J.; L'Ecuyer, Tristan S.; He, Haozhe

doi:https://doi.org/10.5194/acp-25-7299-2025

Articles | Volume 25, issue 13

https://doi.org/10.5194/acp-25-7299-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-25-7299-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 25, issue 13

ACP Letters

| Highlight paper

|

14 Jul 2025

ACP Letters | Highlight paper |

| 14 Jul 2025

Observational constraints suggest a smaller effective radiative forcing from aerosol–cloud interactions

Chanyoung Park, Brian J. Soden, Ryan J. Kramer, Tristan S. L'Ecuyer, and Haozhe He

Supplement

https://doi.org/10.5194/acp-25-7299-2025-supplement

Data sets

Observational Constraints Suggest a Smaller Effective Radiative Forcing from Aerosol-Cloud Interactions (Data) Chanyoung Park et al. https://doi.org/10.5281/zenodo.15795553

Cloud droplet number concentration, calculated from the MODIS (Moderate resolution imaging spectroradiometer) cloud optical properties retrieval and gridded using different sampling strategies E. Gryspeerdt et al. https://doi.org/10.5285/864a46cc65054008857ee5bb772a2a2b

MODIS Atmosphere L3 Monthly Product S. Platnick et al. https://doi.org/10.5067/MODIS/MOD08_M3.061

MODIS Atmosphere L3 Monthly Product S. Platnick et al. https://doi.org/10.5067/MODIS/MYD08_M3.061

MERRA-2 inst3_3d_aer_Nv NASA https://doi.org/10.5067/LTVB4GPCOTK2

Download

Article (4805 KB)
Full-text XML

Executive editor

Aerosols moderate climate change by modifying cloud properties to make them more reflective to sunlight, but the magnitude of the effect remains very uncertain, with important implications for future climate change. This study combines satellite observations and reanalysis data to calculate a much weaker radiative forcing due to aerosol-cloud interactions than previous studies. The implication is that aerosols may play a smaller role in climate change than has been widely supposed.

Short summary

This study addresses the long-standing challenge of quantifying the impact of aerosol–cloud interactions. Using satellite observations, reanalysis data, and a "perfect-model" cross-validation, we show that explicitly accounting for aerosol–cloud droplet activation rates is key to accurately estimating ERFaci (effective radiative forcing due to aerosol–cloud interactions). Our results indicate a smaller and less uncertain ERFaci than previously assessed, implying the reduced role of aerosol–cloud interactions in shaping climate sensitivity.