Publication Abstracts

Thornhill et al. 2020, accepted

Thornhill, G., W. Collins, D. Olivié, A. Archibald, S. Bauer, R. Checa-Garcia, S. Fiedler, G. Folberth, A. Gjermundsen, L. Horowitz, J.-F. Lamarque, M. Michou, J. Mulcahy, P. Nabat, V. Naik, F.M. O'Connor, F. Paulot, M. Schulz, C.E. Scott, R. Seferian, C. Smith, T. Takemura, S. Tilmes, and J. Weber, 2020: Climate-driven chemistry and aerosol feedbacks in CMIP6 Earth system models. Atmos. Chem. Phys., accepted.

Feedbacks play a fundamental role in determining the magnitude of the response of the climate system to external forcing, such as from anthropogenic emissions. The latest generation of Earth system models include aerosol and chemistry components that interact with each other and with the biosphere. These interactions introduce a complex web of feedbacks which it is important to understand and quantify.

This paper addresses the multiple pathways for aerosol and chemical feedbacks in Earth system models. This is achieved by extending previous formalisms which include CO2 concentrations as a state variable to a formalism which in principle includes the concentrations of all climate-active atmospheric constituents. This framework is demonstrated by applying it to the Earth system models participating in CMIP6 with a focus on the non-CO2 reactive gases and aerosols (methane, ozone, sulphate aerosol, organic aerosol and dust).

We find that the overall climate feedback through chemistry and aerosols is negative in the CMIP6 Earth system models due to increased negative forcing from aerosols with warmer temperatures. Through diagnosing changes in methane emissions and lifetime we find that if Earth system models were to allow methane to vary interactively, methane positive feedbacks (principally wetland methane emissions and biogenic VOC emissions) would offset much of the aerosol feedbacks.

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BibTeX Citation

  author={Thornhill, G. and Collins, W. and Olivié, D. and Archibald, A. and Bauer, S. and Checa-Garcia, R. and Fiedler, S. and Folberth, G. and Gjermundsen, A. and Horowitz, L. and Lamarque, J.-F. and Michou, M. and Mulcahy, J. and Nabat, P. and Naik, V. and O'Connor, F. M. and Paulot, F. and Schulz, M. and Scott, C. E. and Seferian, R. and Smith, C. and Takemura, T. and Tilmes, S. and Weber, J.},
  title={Climate-driven chemistry and aerosol feedbacks in CMIP6 Earth system models},
  journal={Atmos. Chem. Phys.},

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RIS Citation

ID  - th01200v
AU  - Thornhill, G.
AU  - Collins, W.
AU  - Olivié, D.
AU  - Archibald, A.
AU  - Bauer, S.
AU  - Checa-Garcia, R.
AU  - Fiedler, S.
AU  - Folberth, G.
AU  - Gjermundsen, A.
AU  - Horowitz, L.
AU  - Lamarque, J.-F.
AU  - Michou, M.
AU  - Mulcahy, J.
AU  - Nabat, P.
AU  - Naik, V.
AU  - O'Connor, F. M.
AU  - Paulot, F.
AU  - Schulz, M.
AU  - Scott, C. E.
AU  - Seferian, R.
AU  - Smith, C.
AU  - Takemura, T.
AU  - Tilmes, S.
AU  - Weber, J.
PY  - 2020
TI  - Climate-driven chemistry and aerosol feedbacks in CMIP6 Earth system models
JA  - Atmos. Chem. Phys.
ER  -

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