Impact on cloud properties of reduced-sulphur shipping fuel in the Eastern North Atlantic

Mace, Gerald G.; Benson, Sally; Gombert, Peter; Smallwood, Tiffany

doi:10.5194/acp-26-1041-2026

Articles | Volume 26, issue 2

https://doi.org/10.5194/acp-26-1041-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-26-1041-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 2

ACP Letters

| Highlight paper

|

22 Jan 2026

ACP Letters | Highlight paper |

| 22 Jan 2026

Impact on cloud properties of reduced-sulphur shipping fuel in the Eastern North Atlantic

Gerald G. Mace, Sally Benson, Peter Gombert, and Tiffany Smallwood

Supplement

https://doi.org/10.5194/acp-26-1041-2026-supplement

Data sets

Microwave Radiometer, 3 Channel (MWR3C) M. Cadeddu et al. https://doi.org/10.5439/1025248

Ka ARM Zenith Radar (KAZR2CFRGE) Y.-C. Feng et al. https://doi.org/10.5439/1891991

Balloon-Borne Sounding System (SONDEWNPN) E. Keeler et al. https://doi.org/10.5439/1595321

Cloud Condensation Nuclei Particle Counter (AOSCCN2COLASPECTRA). A. Koontz et al. https://doi.org/10.5439/1323896

Micropulse Lidar (MPLPOLFS) P. Muradyan et al. https://doi.org/10.5439/1320657

MODIS atmosphere L2 cloud product (06_L2), Terra, NASA MODIS Adaptive Processing System S. Platnick et al. https://doi.org/10.5067/MODIS/MOD06_L2.006

NASA/LARC/SD/ASDC. (2014). CERES Single Scanner Footprint (SSF) TOA/Surface Fluxes, Clouds and Aerosols Terra-FM2 Edition4A NASA/LARC/SD/ASDC https://doi.org/10.5067/TERRA/CERES/SSF-FM2_L2.004A

NASA/LARC/SD/ASDC. (2014). CERES Single Scanner Footprint (SSF) TOA/Surface Fluxes, Clouds and Aerosols Aqua-FM3 Edition4A NASA/LARC/SD/ASDC https://doi.org/10.5067/AQUA/CERES/SSF-FM3_L2.004A

Surface Meteorological Instrumentation (MET) J. Kyrouac et al. https://doi.org/10.5439/1786358

Model code and software

mpact on cloud properties of reduced sulfur fuel in the Eastern North Atlantic, Dataset S. Benson and G. G. Mace https://doi.org/10.7278/S5d-ppzy-3nkj

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Following the 2020 global reduction in shipping fuel sulphur, a natural experiment revealed significant changes in marine boundary layer (MBL) cloud properties over the Eastern North Atlantic. These new observations show a ~15% drop in cloud condensation nuclei, leading to fewer but larger cloud droplets. Normally, this would change how clouds reflect sunlight, but an increase in liquid water path (LWP) counteracted these effects. As a result, cloud optical depth and albedo changed very little. Simultaneous shifts in large-scale meteorology, including weaker inversion strength and increased dry air mixing, further complicated attribution of the observed cloud changes. The study suggests that overall, the cooling influence of marine boundary layer clouds seems to be weakening with implications for future climate feedbacks.