EGU21-8693, updated on 13 Sep 2023
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Aerosol-forced AMOC changes in CMIP6 historical simulations.

Matthew Menary1,2, Richard Allan4, Jon Robson3, Ben Booth5, Christophe Cassou6, Jonathan Gregory3,5, Dan Hodson3, Colin Jones7, Juliette Mignot1, Mark Ringer5, Rowan Sutton3, Laura Wilcox3, Rong Zhang8, and Guillaume Gastineau1
Matthew Menary et al.
  • 1LOCEAN, Sorbonne Université, Paris, France (
  • 2LMD, Ecole Normale Supérieure, France
  • 3NCAS, Department of Meteorology, University of Reading, UK
  • 4Department of Meteorology, University of Reading, UK
  • 5Met Office Hadley Centre, Met Office, UK
  • 6CECI CNRS-Cerfacs, France
  • 7NCAS, School of Earth and the Environment, University of Leeds, UK
  • 8NOAA/GFDL, Princeton, USA

The Atlantic Meridional Overturning Circulation (AMOC) has been, and will continue to be, a key factor in the modulation of climate change both locally and globally. However, there remains considerable uncertainty in recent AMOC evolution. Here, we show that the multi-model mean AMOC strengthened by approximately 10% from 1850-1985 in new simulations from the 6th Coupled Model Inter-comparison Project (CMIP6), a larger change than was seen in CMIP5. Across the models, the strength of the AMOC trend up to 1985 is related to a proxy for the strength of the aerosol forcing. Therefore, the multi-model difference is a result of stronger anthropogenic aerosol forcing on average in CMIP6 than CMIP5, which is primarily due to more models including aerosol-cloud interactions. However, observational constraints - including a historical sea surface temperature fingerprint and shortwave radiative forcing in recent decades - suggest that anthropogenic forcing and/or the AMOC response may be overestimated.

How to cite: Menary, M., Allan, R., Robson, J., Booth, B., Cassou, C., Gregory, J., Hodson, D., Jones, C., Mignot, J., Ringer, M., Sutton, R., Wilcox, L., Zhang, R., and Gastineau, G.: Aerosol-forced AMOC changes in CMIP6 historical simulations., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8693,, 2021.


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