Exploring the geoengineering of climate using stratospheric sulfate aerosols: The role of particle size
Article first published online: 26 JAN 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 2, January 2008
How to Cite
2008), Exploring the geoengineering of climate using stratospheric sulfate aerosols: The role of particle size, Geophys. Res. Lett., 35, L02809, doi:10.1029/2007GL032179., , and (
- Issue published online: 26 JAN 2008
- Article first published online: 26 JAN 2008
- Manuscript Accepted: 19 DEC 2007
- Manuscript Revised: 26 NOV 2007
- Manuscript Received: 1 OCT 2007
- climate change;
- global warming
 Aerosols produced in the lower stratosphere can brighten the planet and counteract some of the effects of global warming. We explore scenarios in which the amount of precursors and the size of the aerosol are varied to assess their interactions with the climate system. Stratosphere-troposphere exchange processes change in response to greenhouse gas forcing and respond to geoengineering by aerosols. Nonlinear feedbacks influence the amount of aerosol required to counteract the warming. More aerosol precursor must be injected than would be needed if stratosphere troposphere exchange processes did not change in response to greenhouse gases or aerosols. Aerosol particle size has an important role in modulating the energy budget. A prediction of aerosol size requires a much more complex representation and assumptions about the delivery mechanism beyond the scope of this study, so we explore the response when particle size is prescribed. More aerosol is required to counteract greenhouse warming if aerosol particles are as large as those seen during volcanic eruptions (compared to the smaller aerosols found in quiescent conditions) because the larger particles are less effective at scattering incoming energy, and trap some outgoing energy. About 1.5 Tg S/yr are found to balance a doubling of CO2 if the particles are small, while perhaps double that may be needed if the particles reach the size seen following eruptions.