Interpreting differences in radiative feedbacks from aerosols versus greenhouse gases

Salvi, P., Ceppi, P. and Gregory, J. M. ORCID: https://orcid.org/0000-0003-1296-8644 (2022) Interpreting differences in radiative feedbacks from aerosols versus greenhouse gases. Geophysical Research Letters, 49 (8). e2022GL097766. ISSN 0094-8276 doi: 10.1029/2022GL097766

Abstract/Summary

Experiments with seven Coupled Model Intercomparison Project phase 6 models were used to assess the climate feedback parameter for net historical, historical greenhouse gas (GHG) and anthropogenic aerosol forcings. The net radiative feedback is found to be more amplifying (higher effective climate sensitivity) for aerosol than GHG forcing, and hence also less amplifying for net historical (GHG + aerosol) than GHG only. We demonstrate that this difference is consistent with their different latitudinal distributions. Historical aerosol forcing is most pronounced in northern extratropics, where the boundary layer is decoupled from the free troposphere, so the consequent temperature change is confined to low altitude and causes low-level cloud changes. This is caused by change in stability, which also affects upper-tropospheric clear-sky emission, affecting both shortwave and longwave radiative feedbacks. This response is a feature of extratropical forcing generally, regardless of its sign or hemisphere.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/104789
Identification Number/DOI	10.1029/2022GL097766
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS
Publisher	American Geophysical Union
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