Effects of stratospheric sulfate aerosol geo-engineering on cirrus clouds
Article first published online: 4 DEC 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 23, 16 December 2012
How to Cite
2012), Effects of stratospheric sulfate aerosol geo-engineering on cirrus clouds, Geophys. Res. Lett., 39, L23803, doi:10.1029/2012GL053797., , and (
- Issue published online: 4 DEC 2012
- Article first published online: 4 DEC 2012
- Manuscript Accepted: 2 NOV 2012
- Manuscript Revised: 26 OCT 2012
- Manuscript Received: 5 SEP 2012
- aerosol effects;
- cirrus clouds;
 Cooling the Earth through the injection of sulphate into the stratosphere is one of the most discussed geo-engineering (GE) schemes. Stratospheric aerosols can sediment into the troposphere, modify the aerosol composition and thus might impact cirrus clouds. We use a global climate model with a physically based parametrization for cirrus clouds in order to investigate possible microphysical and dynamical effects. We find that enhanced stratospheric aerosol loadings as proposed by several GE approaches will likely lead to a reduced ice crystal nucleation rate and thus optically thinner cirrus clouds. These optically thinner cirrus clouds exert a strong negative cloud forcing in the long-wave which contributes by 60% to the overall net GE forcing. This shows that indirect effects of stratospheric aerosols on cirrus clouds may be important and need to be considered in order to estimate the maximum cooling derived from stratospheric GE.