Solar geoengineering involves deliberately modifying the amount of solar radiation that reaches Earth’s surface, and it has been proposed as a means of counteracting some of the negative impacts of climate change. Because large-scale geoengineering experiments, such as deploying giant mirrors to reflect sunlight away from Earth’s surface, are not generally practical, global climate models are the best available tools for assessing the potential consequences of such actions.
Of the many solar geoengineering methods that have been proposed, one considered the most feasible is the injection of sulfur dioxide into the stratosphere. This process mimics the cooling effects of volcanic eruptions by adding a substantial amount of reflective particulates to this atmospheric layer. But because the effects of these injections are not always clear, previous models have been unable to paint a complete picture of their potential consequences.
To address this challenge, Kravitz et al. have introduced the state-of-the-art Community Earth System Model (CESM1), which utilizes the Whole Atmosphere Community Climate Model (WACCM) to perform global chemistry modeling. Unlike other climate models, CESM1 includes some of the most important processes associated with stratospheric sulfur injections, including stratospheric chemical reactions.
This special issue includes a series of studies that explore how variations in altitude, latitude, and the size of the injections can alter the simulation results and improve our understanding of the resulting changes to the surface climate and the stratosphere. Collectively, these articles represent an important first attempt to evaluate whether stratospheric sulfur dioxide injections can be designed to meet precise climate objectives. By better elucidating what these injections and potentially other climate interventions can—and cannot—accomplish, this issue offers a new road map for assessing the effects of solar geoengineering. (Journal of Geophysical Research: Atmospheres, https://doi.org/10.1029/2018JD029293, 2019)
—Terri Cook, Freelance Writer