EGU2020-2379, updated on 13 Sep 2023
EGU General Assembly 2020
© 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, Jon Robson2, Richard Allan3, Ben Booth4, Christophe Cassou5, Guillaume Gastineau1, Jonathan Gregory2,4, Dan Hodson2, Colin Jones6, Juliette Mignot1, Mark Ringer4, Rowan Sutton2, Laura Wilcox2, and Rong Zhang7
Matthew Menary et al.
  • 1LOCEAN, Sorbonne Université, Paris, France
  • 2NCAS, Department of Meteorology, University of Reading, UK
  • 3Department of Meteorology, University of Reading, UK
  • 4Met Office Hadley Centre, Met Office, Exeter, UK
  • 5CECI CNRS-Cerfacs, Toulouse, France
  • 6NCAS, School of Earth and the Environment, University of Leeds, UK
  • 7NOAA/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. Reliable simulations of its decadal to century-timescale evolution are key to providing skilful predictions of future regional climate, and to understanding the likelihood of a potential AMOC collapse. However, there remains considerable uncertainty even in past AMOC evolution. Here, we show that the multi-model mean AMOC strengthened by approximately 10% to 1985 in new historical simulations for the 6th Coupled Model Inter-comparison Project (CMIP6), contrary to results obtained from CMIP5. The simulated strengthening is due to a stronger anthropogenic aerosol forcing, in particular due to aerosol-cloud interactions. However, comparison with an observed sea surface temperature fingerprint of AMOC evolution during 1850-1985, and the shortwave forcing during 1985-2014, suggest that anthropogenic forcing and the subsequent AMOC response may be overestimated in some CMIP6 models.

How to cite: Menary, M., Robson, J., Allan, R., Booth, B., Cassou, C., Gastineau, G., Gregory, J., Hodson, D., Jones, C., Mignot, J., Ringer, M., Sutton, R., Wilcox, L., and Zhang, R.: Aerosol-forced AMOC changes in CMIP6 historical simulations., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2379,, 2020.