Holistic Assessment of SO2 Injections Using CESM1(WACCM): Introduction to the Special Issue. Issue 2 (17th January 2019)

• Record Type: Journal Article
• Authors: Kravitz, Ben; MacMartin, Douglas G.; Tilmes, Simone; Richter, Jadwiga H.; Mills, Michael J.; Lamarque, Jean‐Francois; Tribbia, Joseph; Large, William
• Is Part Of: Journal of geophysical research. Volume 124:Issue 2(2019)
• Page Start: 444
• Page End: 450
• Publication Date: 2019-01-17
• Subjects: geoengineering -- climate engineering -- CESM -- WACCM; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2018JD029293
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: We introduce a special issue on a holistic assessment of solar geoengineering via stratospheric SO2 injection in the state‐of‐the‐art climate model, Community Earth System Model, version 1 with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1(WACCM)). This model has numerous complexities that allow it to represent some of the most important nonlinearities associated with stratospheric SO2 injection, including aerosol microphysical growth and stratospheric chemistry. The studies described herein represent the steps toward and first attempt in a state‐of‐the‐art climate model to use solar geoengineering to meet multiple simultaneous objectives via SO2 injection at multiple locations. First, a set of simulations was carried out to better understand the response of the model to variations in latitude, altitude, and amount of sulfur dioxide injections. Subsequently, in a century‐long simulation, a feedback algorithm was employed to meet specific objectives and manage uncertainty, wherein the injection amount at each location was adjusted every model year. Most of the analyses contained in this special issue focus on surface climate and stratospheric changes in the simulations. In addition, 20 ensemble members of the feedback simulation have been carried out and provided to the community (the Geoengineering Large Ensemble) to expand the scope of analyses to low signal‐to‐noise ratio fields, including regional effects, impacts assessment, and extreme events. The demonstration provided by these simulations is a step toward understanding the space of achievable climate objectives via solar geoengineering or, phrased differently, determining what solar geoengineering can do and what it cannot do. Key Points: CESM1(WACCM) is a state‐of‐the‐art climate model suitable for stratospheric aerosol geoengineering studies Feedback can manage uncertainty even in complicated, nonlinear Earth System Models Further research is needed to understand the space of achievable climate objectives via geoengineering