The impact of geoengineering aerosols on stratospheric temperature and ozone

By P. Heckendorn, D. Weisenstein, S. Fueglistaler, B. Luo, Eugene V. Rozanov, M. Schraner, L. Thomason, T. Peter. 2009

255 citations recorded by the source corpus.

Anthropogenic greenhouse gas emissions are warming the global climate at an unprecedented rate. Significant emission reductions will be required soon to avoid a rapid temperature rise. As a potential interim measure to avoid extreme temperature increase, it has been suggested that Earth’s albedo be increased by artificially enhancing stratospheric sulfate aerosols. We use a 3D chemistry climate model, fed by aerosol size distributions from a zonal mean aerosol model, to simulate continuous injection of 1–10 Mt/a into the lower tropical stratosphere. In contrast to the case for all previous work, the particles are predicted to grow to larger sizes than are observed after volcanic eruptions. The reason is the continuous supply of sulfuric acid and hence freshly formed small aerosol particles, which enhance the formation of large aerosol particles by coagulation and, to a lesser extent, by condensation. Owing to their large size, these particles have a reduced albedo. Furthermore, their sedimentation results in a non-linear relationship between stratospheric aerosol burden and annual injection, leading to a reduction of the targeted cooling. More importantly, the sedimenting particles heat the tropical cold point tropopause and, hence, the stratospheric entry mixing ratio of H2O increases. Therefore, geoengineering by means of sulfate aerosols is predicted to accelerate the hydroxyl catalyzed ozone destruction cycles and cause a significant depletion of the ozone layer even though future halogen concentrations will be significantly reduced.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/c0198cc9641269e5bd01e1cbb9006794e7605aa0

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Citations in the corpus

An overview of the Earth system science of solar geoengineering (2016, background): “This gas then oxidizes over a period of weeks to form sulfuric acid, which condenses to form aerosol particles.(54) Once the aerosols are formed, particles begin to coagulate, and gaseous precursors condense onto existing aerosol particles, resulting in larger aerosol sizes.”
The Climate Response to Stratospheric Aerosol Geoengineering Can Be Tailored Using Multiple Injection Locations (2017, methodology): “For this study, we inject SO2, as in a variety of previous studies (e.g., Aquila et al., 2014; English et al., 2012; Heckendorn et al., 2009; Niemeier & Timmreck, 2015; Pitari et al., 2014).”
Stratospheric ozone response to sulfate geoengineering: Results from the Geoengineering Model Intercomparison Project (GeoMIP) (2014, background): “ULAQ-CCM is the only model included in this study which can represent aerosol microphysical growth; it shows a substantial increase in sulfate aerosol effective radius, consistent with past studies [Heckendorn et al., 2009; English et al., 2012].”
The Regional Hydroclimate Response to Stratospheric Sulfate Geoengineering and the Role of Stratospheric Heating (2019, background): “…radiation and therefore act to cool the surface and the troposphere, but can also absorb infrared radiation (e.g., Stenchikov et al., 1998), resulting in a warming of the lower stratosphere where they reside (e.g., Ammann et al., 2010; Ferraro et al., 2011; Heckendorn et al., 2009; Robock, 2000).”
Photophoretic levitation of engineered aerosols for geoengineering (2010, background): “This substantially limits the radiative forcing produced by large sulfur injections and can make it difficult to produce a radiative forcing sufficient to offset the radiative effect of a CO2 doubling (4).”